Subpart B - Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures

§86.101 General applicability.

(a) General provisions. This subpart describes test procedures for measuring exhaust, evaporative, and refueling emissions from motor vehicles subject to emission standards under subpart S of this part. This generally includes light-duty vehicles, light-duty trucks, and complete heavy-duty vehicles at or below 14,000 pounds GVWR. The following provisions apply for all testing under this subpart:

(1) Provisions of this subpart apply to tests performed by both the Administrator and manufacturers.

§86.102 Definitions.

The definitions in §86.1803 apply to this subpart.

[79 FR 23692, Apr. 28, 2014]

§86.103 Abbreviations.

The abbreviations in subpart A apply to this subpart.

[45 FR 14508, Mar. 5, 1980]

§86.104 Section numbering; construction.

(a) The model year of initial applicability is indicated by the section number. The two digits following the hyphen designate the first model year for which a section is effective. A section remains effective until superseded.

Example.

Section 86.111-78 applies to the 1978 and subsequent model years until superseded. If a §86.111-81 is promulgated it would take effect beginning with the 1981 model year; §86.111-78 would apply to model years 1978 through 1980.

(b) A section reference without a model year suffix refers to the section applicable for the appropriate model year.

(c) Unless indicated otherwise, all provisions in this subpart apply to petroleum-fueled, natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled vehicles.

[42 FR 32954, June 28, 1977. Redesignated at 45 FR 14508, Mar. 5, 1980, as amended at 54 FR 14499, Apr. 11, 1989; 59 FR 48504, Sept. 21, 1994]

§86.105 Introduction; structure of subpart.

(a) This subpart describes the equipment required and the procedures to follow in order to perform gaseous exhaust, particulate, and evaporative emission tests on light-duty vehicles and light-duty trucks. Subpart A of this part sets forth testing requirements and test intervals necessary to comply with EPA certification procedures. Not all emission measurement techniques described in this subpart will be necessary for all vehicles. Subpart A of this part defines the conditions under which vehicles may be exempted from measuring methane and/or waived from measuring particulate matter.

(b) Three topics are addressed in this subpart. Sections 86.106 through 86.115 set forth specifications and equipment requirements; §§86.116 through 86.126 discuss calibration methods and frequency; test procedures and data requirements are listed in §§86.127 through 86.157.

[56 FR 25760, June 5, 1991, as amended at 59 FR 16295, Apr. 6, 1994; 59 FR 48504, Sept. 21, 1994]

§86.106-96 Equipment required; overview.

(a) This subpart contains procedures for exhaust emission tests on petroleum-fueled, natural gas-fueled, liquefied petroleum gas-fueled, and methanol-fueled light-duty vehicles and light-duty trucks, and for evaporative emission tests on gasoline-fueled, natural gas-fueled, liquefied petroleum gas-fueled, and methanol-fueled light-duty vehicles and light-duty trucks. Certain items of equipment are not necessary for a particular test, e.g., evaporative enclosure when testing petroleum-fueled diesel vehicles. Alternate equipment, procedures, and calculation methods may be used if shown to yield equivalent or superior results, and if approved in advance by the Administrator. Equipment required and specifications are as follows:

(1) Evaporative emission tests, gasoline-fueled vehicles. The evaporative emission test is closely related to and connected with the exhaust emission test. All vehicles tested for evaporative emissions must undergo testing according to the test sequences described in §86.130-96; however, the Administrator may omit measurement of exhaust emissions to test for evaporative emissions. The Administrator may truncate a test after any valid emission measurement without affecting the validity of the test. Further, unless the evaporative emission test is waived by the Administrator under §86.090-26 or §86.1810, as applicable, all vehicles must undergo both tests. (Petroleum-fueled diesel vehicles are excluded from the evaporative emission standard.) Section 86.107 specifies the necessary equipment.

(2) Exhaust emission tests. All vehicles subject to this subpart are subject to testing for both gaseous and particulate exhaust emissions using the CVS concept (see §86.109), except where exemptions or waivers are expressly provided in subpart A of this part. Vehicles subject to the “Tier 0” (i.e., phase-out) standards described under subpart A of this part are exempted from testing for methane emissions. Otto-cycle vehicles subject to the “Tier 0” standards are waived from testing for particulates. For vehicles waived from the requirement for measuring particulate emissions, use of a dilution tunnel is not required (see §86.109). The CVS must be connected to the dilution tunnel if particulate emission sampling is required (see §86.110). Petroleum- and methanol-fueled diesel-cycle vehicle testing requires that a PDP-CVS or CFV-CVS with heat exchanger be used. (This equipment may be used with methanol-fueled Otto-cycle vehicles; however, particulates need not be measured for vehicles that are waived from the requirement). All vehicles equipped with evaporative canisters are preconditioned by loading the canisters with hydrocarbon vapors. Petroleum-fueled diesel vehicles are excluded from this requirement.

(3) Fuel, analytical gas, and driving schedule specifications. Fuel specifications for exhaust and evaporative emission testing and for mileage accumulation for petroleum-fueled and methanol-fueled vehicles are specified in §86.113. Analytical gases are specified in §86.114. The Urban Dynamometer Driving Schedule (UDDS), US06, and SC03 driving schedules, for use in exhaust emission tests, and the New York City Cycle (NYCC), for use with the UDDS in running loss tests, are specified in §§86.115, 86.130, 86.159, 86.160, and appendix I to this part.

(b) [Reserved]

[58 FR 16026, Mar. 24, 1993, as amended at 59 FR 48504, Sept. 21, 1994; 60 FR 43888, Aug. 23, 1995; 64 FR 23921, May 4, 1999; 79 FR 23692, Apr. 28, 2014]

§86.107-96 Sampling and analytical systems; evaporative emissions.

(a) Testing enclosures- (1) Diurnal emission test. The enclosure shall be readily sealable, rectangular in shape, with space for personnel access to all sides of the vehicle. When sealed, the enclosure shall be gas tight in accordance with §86.117-96. Interior surfaces must be impermeable and nonreactive to hydrocarbons (and to methanol, if the enclosure is used for methanol-fueled vehicles). The temperature conditioning system shall be capable of controlling the internal enclosure air temperature to follow the prescribed temperature versus time cycle as specified in §86.133-96 and appendix II of this part, within an instantaneous tolerance of ±3.0°F of the nominal temperature versus time profile throughout the test, and an average tolerance of 2.0°F over the duration of the test (where the average is calculated using the absolute value of each measured deviation). The control system shall be tuned to provide a smooth temperature pattern that has a minimum of overshoot, hunting, and instability about the desired long-term ambient temperature profile. Interior surface temperatures shall not be less than 40°F at any time during the diurnal emission test. To accommodate the volume changes due to enclosure temperature changes, either a variable-volume or fixed-volume enclosure may be used for diurnal emission testing:

(i) Variable-volume enclosure. The variable-volume enclosure expands and contracts in response to the temperature change of the air mass in the enclosure. Two potential means of accommodating the internal volume changes are movable panel(s), or a bellows design, in which impermeable bag(s) inside the enclosure expand and contract in response to internal pressure changes by exchanging air from outside the enclosure. Any design for volume accommodation must maintain the integrity of the enclosure as specified in §86.117-96 over the specified temperature range. Any method of volume accommodation shall limit the differential between the enclosure internal pressure and the barometric pressure to a maximum value of ±2.0 inches of water. The enclosure shall be capable of latching to a fixed volume. A variable-volume enclosure must be capable of accommodating a ±7 percent change from its “nominal volume” (see §86.117-96(b)), accounting for temperature and barometric pressure variation during testing.

(ii) Fixed-volume enclosure. The fixed-volume enclosure shall be constructed with rigid panels that maintain a fixed enclosure volume, and meet the following requirements.

(A) The enclosure shall be equipped with a mechanism to maintain a fixed internal air volume. This may be accomplished either by withdrawing air at a constant rate and providing makeup air as needed, or by reversing the flow of air into and out of the enclosure in response to rising or falling temperatures. If inlet air is added continuously throughout the test, it should be filtered with activated carbon to provide a relatively low and constant hydrocarbon level. Any method of volume accommodation shall maintain the differential between the enclosure internal pressure and the barometric pressure to a maximum value of ±2.0 inches of water.

(B) The equipment shall be capable of measuring the mass of hydrocarbon and methanol (if the enclosure is used for methanol-fueled vehicles) in the inlet and outlet flow streams with a resolution of 0.01 gram per hour. A bag sampling system may be used to collect a proportional sample of the air withdrawn from and admitted to the enclosure. Alternatively, the inlet and outlet flow streams may be continuously analyzed using an on-line FID analyzer and integrated with the flow measurements to provide a continuous record of the mass hydrocarbon and methanol removal.

(2) Running loss test. The enclosure shall be readily sealable, rectangular in shape, with space for personnel access to all sides of the vehicle. When sealed, the enclosure shall be gas tight in accordance with §86.117-96. The enclosure may be equipped with a personnel door, provided that the enclosure can still meet the requirements of §86.117-96 with the door installed. Interior surfaces must be impermeable and nonreactive to hydrocarbons and to methanol (if the enclosure is used for methanol-fueled vehicles). Interior surface temperatures shall not be less than 40°F. If a running loss enclosure meets all the requirements of paragraph (a)(1) of this section, it may be used as a diurnal evaporative emission enclosure. The enclosure must contain a dynamometer that meets the requirements of §86.108. Provisions shall be made to remove exhaust gases from the enclosure. During the running loss test, ambient temperatures must be maintained at 95±5°F (95±2°F on average). An air or oxygen cylinder with an attached self-contained breathing apparatus may be provided for the vehicle operator. The air required for vehicle operation shall be provided by one of the following methods:

(i) The running loss enclosure may be equipped to supply air to the vehicle, at a temperature of 95±5°F, from sources outside of the running loss enclosure directly into the operating engine's air intake system. Supplemental air requirements (e.g., for an air pump) shall be supplied by drawing air from the engine intake source.

(ii) If it is shown to yield equivalent or superior results, the running loss enclosure may be designed with an air makeup system that brings outside air into the enclosure to accommodate the aspiration needs of the engine and any auxiliary devices. The makeup air shall be monitored to establish the background hydrocarbon levels (or hydrocarbon and methanol, levels, if applicable) of the makeup air. A filter may be used to provide dry air with a stable concentration of background hydrocarbon. The makeup-air vent shall be readily sealable for calibration of the enclosure and other purposes. For calculation of running loss emissions, it may be assumed that the hydrocarbon and methanol concentration in the air consumed by the vehicle is the same as that of the rest of the air in the enclosure.

(3) Hot soak test. The hot soak test may be conducted by holding the vehicle in an enclosure that meets the requirements for either diurnal emission or running loss tests. The enclosure shall be configured to provide an internal enclosure ambient temperature of 95±10°F for the first 5 minutes, and 95±5°F (95±2°F on average) for the remainder of the hot soak test.

(i) If the hot soak test is conducted in the same enclosure as the immediately preceding running loss test, interior surface temperatures shall not be below 70°F for the last 55 minutes of the hot soak test.

(ii) If the hot soak test is not conducted in the same enclosure as the immediately preceding running loss test, interior surface temperatures shall not be below 70°F for the duration of the hot soak test.

(b) Evaporative emission hydrocarbon and methanol analyzers. (1) For gasoline fueled, natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled vehicles a hydrocarbon analyzer utilizing the hydrogen flame ionization principle (FID) shall be used to monitor the atmosphere within the enclosure (a heated FID (HFID)(235°±15°F (113±8°C)) is recommended for methanol-fueled vehicles). For natural gas-fueled vehicles, the FID may be calibrated using methane, or if calibrated using propane the FID response to methane shall be determined and applied to the FID hydrocarbon reading. Provided evaporative emission results are not effected, a probe may be used to detect or verify hydrocarbon sources during a running loss test. Instrument bypass flow may be returned to the enclosure. The FID shall have a response time to 90 percent of final reading of less than 1.5 seconds.

(2) For methanol-fueled vehicles, a methanol sampling and analyzing system is required in addition to the FID analyzer. The methanol sampling equipment shall consist of impingers for collecting the methanol sample and appropriate equipment for drawing the sample through the impingers. The analytical equipment shall consist of a gas chromatograph equipped with a flame ionization detector.

(3) The methanol sampling system shall be designed such that, if a test vehicle emitted the maximum allowable level of methanol (based on all applicable standards) during any phase of the test, the measured concentration in the primary impinger would exceed either 25 mg/l or a concentration equal to 25 times the limit of detection for the GC analyzer, and such that the primary impinger collects at least 90 percent of the analyte in the samples. The remaining analyte shall be collected by the secondary impinger. This requirement does not apply to dilution air samples, since they do not require secondary impingers, or to samples in which the concentrations approach the limit of detection. The provisions of this paragraph apply to the design of sampling systems, not to individual tests.

(c) Evaporative emission hydrocarbon and methanol data recording system.(1) The electrical output of the FID used for measuring hydrocarbons (or hydrocarbons plus methanol, as appropriate) shall be recorded at least at the initiation and termination of each running loss and hot soak test, and at least at the initiation and termination of the enclosure sampling period(s) for the diurnal emission test, as described in §86.133. The recording may be taken by means of a strip chart potentiometric recorder, by use of an on-line computer system or other suitable means. In any case, the recording system must have operational characteristics (signal-to-noise ratio, speed of response, etc.) equivalent to or better than those of the signal source being recorded, and must provide a permanent record of results. The record shall show a positive indication of the initiation and completion of each hot soak, running loss, or diurnal emission test (including initiation and completion of sampling period(s)), along with the time elapsed during each soak.

(2) For the methanol sample, permanent records shall be made of the following: the volumes of deionized water introduced into each impinger, the rate and time of sample collection, the volumes of each sample introduced into the gas chromatograph, the flow rate of carrier gas through the column, the column temperature, and the chromatogram of the analyzed sample.

(d) Fuel temperature control system. Fuel temperatures of the test vehicle shall be controlled, as specified in §86.134(g)(1)(xv), with the following combination of fans. The control system shall be tuned and operated to provide a smooth and continuous fuel temperature profile that is representative of the on-road temperature profile. The running loss test configuration should be designed to avoid heating or cooling the fuel tank's vapor space in a way that would cause vapor temperature behavior to be unrepresentative of the vehicle's on-road profile.

(1) A vehicle cooling fan shall discharge air to the front of the vehicle. The fan shall be a road-speed modulated fan that is controlled to a discharge velocity that follows the dynamometer roll speed, at least up to speeds of 30 mph, throughout the driving cycle. If a warning light or gauge indicates that the vehicle's engine coolant has overheated, subsequent test runs on the vehicle must include a vehicle cooling fan that follows the dynamometer roll speed at all speeds throughout the test cycle. The fan may direct airflow to both the vehicle radiator air inlet(s) and the vehicle underbody.

(2) An additional fan may be used to discharge airflow from the front of the vehicle directly to the vehicle underbody to control fuel temperatures. Such a fan shall provide a total discharge airflow not to exceed 8,000 cfm.

(3) Additional fans may be used to route heating or cooling air directly at the bottom of the vehicle's fuel tank. The air supplied to the tank shall be between 85° and 160°F, with a total discharge airflow not to exceed 4,000 cfm. For exceptional circumstances, manufacturers may direct up to 6,000 cfm at the bottom of the fuel tank with the advance approval of the Administrator.

(4) Direct fuel heating may be needed for canister preconditioning, as specified in §86.132(j)(2), Also, under exceptional circumstances in which airflow alone is insufficient to control fuel temperatures during the running loss test, direct fuel tank heating may be used (see §86.134-96(g)(1)(v)). The heating system must not cause hot spots on the tank wetted surface that could cause local overheating of the fuel. Heat must not be applied directly to the tank's vapor space, nor to the liquid-vapor interface.

(e) [Reserved]

(f) Pressure recording system. A strip chart potentiometric recorder, an on-line computer system, or other suitable means, shall be used to record the enclosure gage pressure for any testing in an enclosure, as well as the vehicle's fuel tank pressure during the running loss test and the outdoor driving procedure specified in §86.129-94(d). Fuel tank pressure measurement and recording equipment are optional during the running loss test. The recording system shall record each pressure at least once every minute. The recording system shall be capable of resolving time to ±15 s and capable of resolving pressure to ±0.1 inches of water. The pressure recording system (recorder and sensor) shall have an accuracy of ±1.0 inch of water. The recorder (data processor) shall have a time accuracy of ±15 s and a precision of ±15 s. The pressure transducer shall be installed to measure the pressure in the vapor space of the fuel tank.

(g) Purge blower. One or more portable or fixed blowers shall be used to purge the enclosure. The blowers shall have sufficient flow capacity to reduce the enclosure hydrocarbon and/or methanol concentration from the test level to the ambient level between tests. Actual flow capacity will depend upon the time available between tests.

(h) Mixing blower. Blowers or fans shall be used to mix the enclosure contents during evaporative emission testing. The inlets and outlets of the air circulation blower(s) shall be configured to provide a well dispersed air circulation pattern that produces effective internal mixing and avoids significant temperature or hydrocarbon stratification. Maintenance of uniform concentrations throughout the enclosure is important to the accuracy of testing.

(1) Diurnal emission test. Blowers or fans shall have a capacity of 0.8±0.2 cfm per cubic foot of the nominal enclosure volume for mixing in the enclosure. Additional fans may be used to maintain a minimum wind speed of 5 mph (8 km/h) under the fuel tank of the test vehicle.

(2) Running loss test. Blowers or fans shall have a total capacity of at least 1.0 cfm per cubic foot of the nominal enclosure volume.

(3) Hot soak test. Blowers or fans must have a capacity of 0.8±0.2 cfm per cubic foot of the nominal enclosure volume. Circulated air shall not be aimed directly at the vehicle.

(i) Point-source running loss measurement facility. Some system requirements pertain specifically to running loss testing by the point-source method, in which emissions from potential sources are collected and routed to a sampling system. Emissions are sampled with the same equipment and techniques as for exhaust emission measurement. The test environment must contain a dynamometer that meets the requirements of §86.108. During the running loss test, ambient temperatures must be maintained at 95±5°F (95±2°F on average). An air or oxygen cylinder with an attached self-contained breathing apparatus may be provided for the vehicle operator.

(1) The running loss vapor vent collection system shall be configured to collect all running loss emissions from each of the discrete point sources that function as vehicle fuel system vapor vents, and transport the collected vapor emissions to a CFV- or PDP-based dilution and measurement system. The collection system shall consist of a collector at each vehicle vapor vent, lengths of heated sample line connecting each collector to the inlet of the heated sample pump, and lengths of heated sample line connecting the outlet of the heated sample pump to the inlet of the running loss fuel vapor sampling system. Up to 3 feet of unheated line connecting each of the vapor collectors to the heated sample lines shall be allowed. Each heated sample pump and its associated sample lines shall be maintained at a temperature between 175°F and 200°F to prevent condensation of fuel vapor in the sample lines. The heated sample pump(s) and its associated flow controls shall be configured and operated to draw a flow of ambient air into each collector at a flow rate of at least 0.67 cfm. The flow controls on each heated sampling system shall include an indicating flow meter that provides an alarm output to the data recording system if the flow rate drops below 0.67 cfm by more than 5 percent. The collector inlet for each discrete vapor vent shall be placed in proximity to the vent as necessary to capture any fuel vapor emissions without significantly affecting flow or pressure of the normal action of the vent. The collector inlets shall be designed to interface with the configuration and orientation of each specific vapor vent. For vapor vents that terminate in a tube or hose barb, a short length of tubing of an inside diameter larger throughout its length than the inside diameter of the vent outlet may be used to extend the vent into the mouth of the collector. For those vapor vent designs that are not compatible with such collector configurations, the vehicle manufacturer shall supply a collector that is configured to interface with the vapor vent design and that terminates in a fitting that is capable of capturing all vapor emitted from the vent. The Administrator may test for running losses by the point-source method without heating sample lines or pumps.

(2) The running loss fuel vapor sampling system shall be a CFV- or PDP-based dilution and measurement system that further dilutes the running loss fuel vapors collected by the vapor vent collection system(s) with ambient air, collects continuously proportional samples of the diluted running loss vapors and dilution air in sample bags, and measures the total dilute flow through the sampling system over each test interval. In practice, the system shall be configured and operated in a manner that is directly analogous to an exhaust emissions constant volume sampling system, except that the input flow to the system is the flow from the running loss vapor vent collection system(s) instead of vehicle exhaust flow. The system shall be configured and operated to meet the following requirements:

(i) The running loss fuel vapor sampling system shall be designed to measure the true mass of fuel vapor emissions collected by the running loss vapor vent collection system from the specified fuel vapor vents. The total volume of the mixture of running loss emissions and dilution air shall be measured and a continuously proportioned sample of volume shall be collected for analysis. Mass emissions shall be determined from the sample concentration and total flow over the test period.

(ii) The PDP-CVS shall consist of a dilution air filter and mixing assembly, heat exchanger, positive-displacement pump, sampling system, and associated valves, pressure and temperature sensors. The PDP-CVS shall conform to the following requirements:

(A) The gas mixture temperature, measured at a point immediately ahead of the positive-displacement pump, shall be within ±10°F of the designed operating temperature at the start of the test. The gas mixture temperature variation from its value at the start of the test shall be limited to ±10°F during the entire test. The temperature measuring system shall have an accuracy and precision of ±2°F.

(B) The pressure gauges shall have an accuracy and precision of ±1.6 inches of water (±0.4 kPa).

(C) The flow capacity of the CVS shall not exceed 350 cfm.

(D) Sample collection bags for dilution air and running loss fuel vapor samples shall be sufficient size so as not to impede sample flow.

(iii) The CFV sample system shall consist of a dilution air filter and mixing assembly, a sampling venturi, a critical flow venturi, a sampling system and assorted valves, and pressure and temperature sensors. The CFV sample system shall conform to the following requirements:

(A) The temperature measuring system shall have an accuracy and precision of ±2°F and a response time of 0.100 seconds of 62.5 percent of a temperature change (as measured in hot silicone oil).

(B) The pressure measuring system shall have an accuracy and precision of ±1.6 inches of water (0.4 kPa).

(C) The flow capacity of the CVS shall not exceed 350 cfm.

(D) Sample collection bags for dilution air and running loss fuel vapor samples shall be of sufficient size so as not to impede sample flow.

(3) An on-line computer system or strip-chart recorder shall be used to record the following additional parameters during the running loss test sequence:

(i) CFV (if used) inlet temperature and pressure.

(ii) PDP (if used) inlet temperature, pressure, and differential pressure.

[58 FR 16027, Mar. 24, 1993, as amended at 59 FR 48505, Sept. 21, 1994; 60 FR 34335, June 30, 1995; 60 FR 43888, Aug. 23, 1995; 79 FR 23692, Apr. 28, 2014]

§86.107-98 Sampling and analytical system.

Section 86.107-98 includes text that specifies requirements that differ from §86.107-96. Where a paragraph in §86.107-96 is identical and applicable to §86.107-98, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.107-96.” Where a corresponding paragraph of §86.107-96 is not applicable, this is indicated by the statement “[Reserved].”

(a)(1)-(a)(3) [Reserved]. For guidance see §86.107-96.

(a)(4) Refueling emissions test. The requirements detailed in §86.107-90 (a)(1) shall apply. Alternatively, an enclosure meeting the specifications detailed in §86.107-96 (a)(1), (2), or (3) may be used if approved in advance by the Administrator. In addition, the enclosure shall have one or more access ports leading to flexible, automatic sealing boots, in the wall(s) of the enclosure. The function of the access port(s) and boots shall be to allow fueling of the test vehicle from a fuel nozzle and hose located outside of the enclosure, with only the spout of the nozzle passing through the automatic sealing opening of the boot during fueling. There shall be no loss in the gas tightness of the enclosure at the opening of the boot either when the nozzle is inserted or when the nozzle is not inserted.

(b)-(d) [Reserved]. For guidance see §86.107-96.

(e) Temperature recording system- (1) For all emission testing. A strip chart potentiometric recorder, an on-line computer system, or other suitable means shall be used to record enclosure ambient temperature during all evaporative emission test segments, as well as vehicle fuel tank temperature during the running loss test. The recording system shall record each temperature at least once every minute. The recording system shall be capable of resolving time to ±15 s and capable of resolving temperature to ±0.75°F (±0.42°C). The temperature recording system (recorder and sensor) shall have an accuracy of ±3°F (±1.7°C). The recorder (data processor) shall have a time accuracy of ±15 s and a precision of ±15 s. Enclosures shall be equipped with two ambient temperature sensors, connected to provide one average output, located 3 feet above the floor at the approximate mid-length of each side wall of the enclosure and within 3 to 12 inches of each side wall. For diurnal emission testing, an additional temperature sensor shall be located underneath the vehicle to provide a temperature measurement representative of the temperature of the air under the fuel tank. For running loss testing, an ambient temperature sensor shall be located at the inlet to the fan that provides engine cooling. Manufacturers shall arrange that vehicles furnished for testing at federal certification facilities be equipped with temperature sensors for measurement of fuel tank temperature. Vehicles shall be equipped with 2 temperature sensors installed to provide an average liquid fuel temperature. The temperature sensors shall be placed to measure the temperature at the mid-volume of the liquid fuel at a fill level of 40 percent of nominal tank capacity. An additional temperature sensor may be placed to measure vapor temperatures approximately at the mid-volume of the vapor space, though measurement of vapor temperatures is optional during the running loss test. In-tank temperature sensors are not required for the supplemental two-diurnal test sequence specified in §86.130-96 or for the refueling test specified in §86.151-98.

(2) Refueling emission testing only. In addition to the enclosure ambient temperature recording system described in paragraph (e)(1) of this section, strip chart recorder(s) or automatic data processor shall be used to record vehicle soak area ambient temperature and dispensed fuel temperature at the nozzle during the test. The temperature recorder(s) or data processor shall record each temperature at least once every 20 seconds (the soak area ambient temperature recorder may be a continuous recording system). The recording system shall be capable of resolving time to ±15s and be capable of resolving temperature to ±0.75°F (0.42°C).

(f)-(h)(3) [Reserved]. For guidance see §86.107-96.

(h)(4) Refueling emission test. Blowers or fans must have a capacity of 0.8±0.2 cfm per cubic foot of the nominal enclosure volume. Circulated air shall not be aimed directly at the vehicle.

(5) Spilled fuel mixing blower; refueling emission test. An explosion-proof blower of 100-200 ft ³/min (2.8-5.7 m ³/min) capacity is required to enhance mixing of vapors from spilled fuel through the enclosure atmosphere during tests. The discharge from this blower shall be directed toward the region of the enclosure floor where fuel spillage during fueling may occur.

(i) [Reserved]. For guidance see §86.107-96.

(j) Refueling equipment. The refueling equipment shall consist of a fuel delivery system with temperature control equipment, fuel flow safety switch, dispensing pump, hose, nozzle and a meter to measure the dispensed fuel volume. The dispensing nozzle shall be a commercial model, not equipped with vapor recovery hardware. A fuel recirculation system may be utilized to avoid trapping of unheated fuel in the hose. The fuel delivery system must be capable of delivering fuel at 67±1.5°F (19.4±0.8°C) and a constant flow rate between 4.2 and 9.8 gal/min (15.9 and 37.1 liter/min) with a tolerance of ±0.3 gal/min (±1.1 liter/min) during the refueling emissions measurement phase of the test. The accuracy of the meter for measuring the dispensed fuel volume shall be ±2 percent at the test flow rate.

[59 FR 16295, Apr. 6, 1994, as amended at 60 FR 43890, Aug. 23, 1995]

§86.108-00 Dynamometer.

(a) The dynamometer shall simulate the road load force and inertia specified for the vehicle being tested, and shall determine the distance traveled during each phase of the test procedure.

(b) Two types of dynamometer roll configurations are currently approved by the Administrator:

(1) A small twin-roll dynamometer that has a nominal roll diameter of 8.65 inches and a nominal roll spacing of 17 inches; and

(2)(i) An electric dynamometer that has a single roll with a nominal diameter of 48 inches (1.20 to 1.25 meters).

(ii)(A) The dynamometer must be capable of dynamically controlling inertia load during the US06 test cycle as a function of a vehicle throttle position signal if a manufacturer desires using the following test option. Any time the duration of throttle operation greater than or equal to 85% of wide open throttle (WOT) is greater than or equal to eight seconds, the test inertia load may be adjusted during any of five EPA specified acceleration events by an amount of load that will eliminate additional throttle operation greater than or equal to 85% of WOT.

(B)(1) The specific US06 schedule accelerations time periods where inertia load adjustments may be applied are:

(i) 49 through 69 seconds;

(ii) 83 through 97 seconds;

(iii) 135 through 165 seconds;

(iv) 315 through 335 seconds; and

(v) 568 through 583 seconds.

(2) During these five time intervals when inertia load adjustment is occurring, inertia load adjustment is discontinued when throttle operation is less than 85% of WOT or at the end of the specified time interval.

(C) Each type of generic application for implementing this concept must receive the Administrator's approval before a manufacturer may use these inertia adjustments for official US06 schedule certification tests.

(c) Other dynamometer configurations may be used for testing if it can be demonstrated that the simulated road load power and inertia are equivalent, and if approved in advance by the Administrator.

(d) An electric dynamometer meeting the requirements of paragraph (b)(2) of this section, or a dynamometer approved as equivalent under paragraph (c) of this section, must be used for all types of emission testing in the following situations.

(1)(i) Gasoline vehicles which are part of an engine family which is designated to meet the phase-in of SFTP compliance required under the implementation schedule of table A00-1 of §86.000-08, or table A00-3, or table A00-5 of §86.000-09.

(ii) Diesel LDVs and LDT1s which are part of an engine family which is designated to meet the phase-in of SFTP compliance required under the implementation schedule of table A00-1 of §86.000-08, or table A00-3, or table A00-5 of §86.000-09.

(2) Starting with the 2002 model year, any light-duty vehicle or light light-duty truck which uses any regulated fuel.

(3) Starting with the 2004 model year, any heavy light-duty truck which uses any regulated fuel.

[61 FR 54890, Oct. 22, 1996]

§86.109-94 Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements.

(a)(1) General. The exhaust gas sampling system described in this paragraph is designed to measure the true mass of gaseous emissions in the exhaust of either Otto-cycle light-duty vehicles or light-duty trucks which are waived from requirements for the measurement of particulate emissions. In the CVS concept of measuring mass emissions, two conditions must be satisfied: the total volume of the mixture of exhaust and dilution air must be measured, and a continuously proportioned volume of sample must be collected for analysis. Mass emissions are determined from the sample concentration and total flow over the test period.

(2) Vehicle tailpipe to CVS Duct. For methanol-fueled vehicles, cooling of the exhaust gases in the duct connecting the vehicle tailpipe to the CVS shall be minimized. This may be accomplished by:

(i) Using a duct of unrestricted length maintained at a temperature above the maximum dew point of the exhaust, but below 250°F (121°C); heating and possibly cooling capabilities are required; or

(ii) Using a short duct (up to 12 feet long) constructed of smooth wall pipe with a minimum of flexible sections, maintained at a temperature above the maximum dew point of the exhaust, but below 250°F (121°C), prior to the test and during the 10 minute hot soak segment and uninsulated during the test (insulation may remain in place and/or heating may occur during testing provided maximum temperature is not exceeded); or

(iii) Using smooth wall duct less than five feet long with no required heating. A maximum of two short flexible connectors are allowed under this option; or

(iv) Omitting the duct and performing the exhaust gas dilution function at the vehicle tailpipe exit.

(3) Positive displacement pump. The Positive Displacement Pump-Constant Volume Sampler (PDP-CVS), Figure B94-1 satisfies the first condition by metering at a constant temperature and pressure through the pump. The total volume is measured by counting the revolutions made by the calibrated positive displacement pump. The proportional samples for the bag sample, and for methanol-fueled vehicles, the methanol sample (Figure B94-2) and the formaldehyde sample (Figure B94-3), are achieved by sampling at a constant flow rate. For methanol-fueled vehicles, the sample lines for the methanol and formaldehyde samples are heated to prevent condensation. The temperature of the sample lines shall be more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C). (Note: For 1990 through 1994 model year methanol-fueled vehicles, methanol and formaldehyde sampling may be omitted provided the bag sample (hydrocarbons and methanol) is analyzed using a HFID calibrated with methanol.)

(4) Critical flow venturi. The operation of the Critical Flow Venturi-Constant Volume Sampler (CFV-CVS) sample system, Figure B94-4, is based upon the principles of fluid dynamics associated with critical flow. Proportional sampling throughout temperature excursions is maintained by use of small CFVs in the sample lines (for methanol-fueled vehicles, one line supplies sample for the bag sample, another line supplies sample for the methanol sample, and a third line supplies sample for the formaldehyde sample.) The methanol and formaldehyde sample lines are heated to prevent condensation. The temperature of the sample lines shall be more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C). Care should be taken to ensure that the CFVs of the sample probes are not heated since heating of the CFVs would cause loss of proportionality. The variable mixture flow rate is maintained at sonic velocity, is inversely proportional to the square root of the gas temperature, and is computed continuously. Since the pressure and temperature are the same at all venturi inlets, the sample volume is proportional to the total volume. (Note: For 1990 through 1994 model year methanol-fueled vehicles, methanol and formaldehyde sampling may be omitted provided the bag sample (hydrocarbons and methanol) is analyzed using a HFID calibrated with methanol.)

(5) Electronic flow control. The Critical Flow Venturi-Electronic Flow Control-Constant Volume Sampler (CFV-EFC-CVS) system is identical to the CFV-CVS system described in paragraphs (a)(4) and (c) of this section, except that it maintains proportional sampling for methanol and formaldehyde by measuring the CVS flow rate, and electronically controlling sample flow rates. For methanol-fueled vehicles, the samples lines for the methanol and formaldehyde samples are heated to prevent condensation. The temperature of the sample lines shall be more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C).

(6) Other systems. Other sampling systems may be used if shown to yield equivalent or superior results, and if approved in advance by the Administrator.

(b) Component description, PDP-CVS. The PDP-CVS, Figure B94-1, consists of a dilution air filter and mixing assembly, heat exchanger, positive displacement pump, sampling systems (see Figure B94-2 for methanol sampling system and Figure B94-3 for formaldehyde sampling system) sampling lines which are heated to a temperature that is more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C) in the case of the methanol-fueled vehicles (heating of the sample lines may be omitted, provided the methanol and formaldehyde sample collection systems are close coupled to the probes thereby preventing loss of sample due to cooling and resulting condensation in the sample lines), and associated valves, pressure and temperature sensors. The PDP-CVS shall conform to the following requirements:

(1) Static pressure variations at the tailpipe(s) of the vehicle shall remain within ±5 inches of water (1.2 kPa) of the static pressure variations measured during a dynamometer driving cycle with no connection to the tailpipe(s). (Sampling systems capable of maintaining the static pressure to within ±1 inch of water (0.25 kPa) will be used by the Administrator if a written request substantiates the need for this closer tolerance.)

(2) The gas mixture temperature, measured at a point immediately ahead of the positive displacement pump, shall be within ±10°F (±5.6°C) of the designed operating temperature at the start of the test. The gas mixture temperature variation from its value at the start of the test shall be limited to ±10°F (±5.6°C) during the entire test. The temperature measuring system shall have an accuracy and precision of ±2°F (1.1°C).

(3) The pressure gauges shall have an accuracy and precision of ±1.6 inches of water (0.4 kPa).

(4) The flow capacity of the CVS shall be large enough to completely eliminate water condensation in the dilution and sampling systems. (300 to 350 cfm (0.142 to 0.165 m ³/s) is sufficient for most petroleum-fueled vehicles. Higher flow rates are required for methanol-fueled vehicles and may be required for natural gas-fueled and liquefied petroleum gas-fueled vehicles. Procedures for determining CVS flow rates are detailed in “Calculation of Emissions and Fuel Economy When Using Alternative Fuels,” EPA 460/3-83-009.) (Copies may be obtained from U.S. Department of Commerce, NTIS, Springfield, Virginia 22161; order #PB84104702.) Dehumidifying the dilution air before entering the CVS is allowed. Hearing the dilution air is also allowed, provided:

(i) The air (or air plus exhaust gas) temperature does not exceed 250°F.

(ii) Calculation of the CVS flow rate necessary to prevent water condensation is based on the lowest temperature encountered in the CVS prior to sampling. (It is recommended that the CVS system be insulated when heated dilution air is used.)

(iii) The dilution ratio is sufficiently high to prevent condensation in bag samples as they cool to room temperature.

(5) Sample collection bags for dilution air and exhaust samples shall be of sufficient size so as not to impede sample flow. A single dilution air sample, covering the total test period, may be collected for the determination of methanol and formaldehyde background (methanol-fueled vehicles).

(6) The methanol sample collection system and the formaldehyde sample collection system shall each be of sufficient capacity so as to collect samples of adequate size for analysis without significant impact on the volume of dilute exhaust passing through the PDP. The systems shall also comply with the following requirements that apply to the design of the systems, not to individual tests.

(i) The methanol system shall be designed such that, if a test vehicle emitted the maximum allowable level of methanol (based on all applicable standards) during the first phase of the test, the measured concentration in the primary impinger would exceed either 25 mg/l or a concentration equal to 25 times the limit of detection for the GC analyzer. Sampling systems for all phases shall be identical.

(ii) The formaldehyde system shall be designed such that, if a test vehicle emitted formaldehyde at a rate equal to twenty percent of the maximum allowable level of NMHCE (i.e., 0.05 g/mi for a 0.25 g/mi NMHCE standard), or the maximum formaldehyde level allowed by a specific formaldehyde standard, whichever is less, during the first phase of the test, the concentration of formaldehyde in the DNPH solution of the primary impinger, or solution resulting from the extraction of the DNPH cartridge, shall exceed either 2.5 mg/l or a concentration equal to 25 times the limit of detection for the HPLC analyzer. Sampling systems for all phases shall be identical.

(iii) The methanol and formaldehyde impinger systems shall be designed such that the primary impinger collects at least 90 percent of the analyte in the samples. The remaining analyte shall be collected by the secondary impinger. This requirement does not apply to dilution air samples, since they do not require secondary impingers, or to samples in which the concentrations approach the limit of detection.

(c) Component description, CFV-CVS. The CFV-CVS sample system, Figure B94-4, consists of a dilution air filter and mixing assembly, a cyclone particulate separator, unheated sampling venturies for the bag samples, and for the methanol and formaldehyde samples from methanol-fueled vehicles, samples lines heated to a temperature that is more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C) for the methanol and formaldehyde samples from methanol fueled vehicles (heating of the sample lines may be omitted provided, the methanol and formaldehyde sample collection systems are close coupled to the probes thereby preventing loss of sample due to cooling and resulting condensation in the sample lines), a critical flow venturi, and assorted valves, and pressure and temperature sensors. The CFV sample system shall conform to the following requirements:

(1) Static pressure variations at the tailpipe(s) of the vehicle shall remain within ±5 inches of water (1.2 kPa) of the static pressure variations measured during a dynamometer driving cycle with no connection to the tailpipe(s). (Sampling systems capable of maintaining the static pressure to within ±1 inch of water (0.25 kPa) will be used by the Administrator if a written request substantiates the need for this closer tolerance.)

(2) The temperature measuring system shall have an accuracy and precision of ±2°F (1.1°C) and a response time of 0.100 seconds to 62.5 percent of a temperature change (as measured in hot silicone oil).

(3) The pressure measuring system shall have an accuracy and precision of ±1.6 inches of water (0.4 kPa).

(4) The flow capacity of the CVS shall be large enough to completely eliminate water condensation in the dilution and sampling systems. (300 to 350 cfm (0.142 to 0.165 m ³/s) is sufficient for most petroleum-fueled vehicles. Higher flow rates are required for methanol-fueled vehicles and may be required for natural gas-fueled and liquefied petroleum gas-fueled vehicles. Procedures for determining CVS flow rates are detailed in “Calculation of Emissions and Fuel Economy When Using Alternative Fuels,” EPA 460/3-83-009.) Dehumidifying the dilution air before entering the CVS is allowed. Heating the dilution air is also allowed, provided:

(i) The air (or air plus exhaust gas) temperature does not exceed 250°F (121°C).

(ii) Calculation of the CVS flow rate necessary to prevent water condensation is based on the lowest temperature encountered in the CVS prior to sampling. (It is recommended that the CVS system be insulated when heated dilution air is used.)

(iii) The dilution ratio is sufficiently high to prevent condensation in bag samples as they cool to room temperature.

(5) Sample collection bags for dilution air and exhaust samples shall be of sufficient size so as not to impede sample flow. A single dilution air sample, covering the total test period, may be collected for the determination of methanol and formaldehyde background (methanol-fueled vehicles).

(6) The methanol sample collection system and the formaldehyde sample collection system shall each be of sufficient capacity so as to collect samples of adequate size for analysis without significant impact on the volume of dilute exhaust passing through the CVS. The systems shall also comply with the following requirements that apply to the design of the systems, not to individual tests.

(i) The methanol system shall be designed such that, if a test vehicle emitted the maximum allowable level of methanol (based on all applicable standards) during the first phase of the test, the measured concentration in the primary impinger would exceed either 25 mg/l or a concentration equal to 25 times the limit of detection for the GC analyzer. Sampling systems for all phases shall be identical.

(ii) The formaldehyde system shall be designed such that, if a test vehicle emitted formaldehyde at a rate equal to twenty percent of the maximum allowable level of NMHCE (i.e., 0.05 g/mi for a 0.25 g/mi NMHCE standard), or the maximum formaldehyde level allowed by a specific formaldehyde standard, whichever is less, during the first phase of the test, the concentration of formaldehyde in the DNPH solution of the primary impinger, or solution resulting from the extraction of the DNPH cartridge, shall exceed either 2.5 mg/l or a concentration equal to 25 times the limit of detection for the HPLC analyzer. Sampling systems for all phases shall be identical.

(iii) The methanol and formaldehyde systems shall be designed such that the primary impinger collects at least 90 percent of the analyte in the samples. The remaining analyte shall be collected by the secondary impinger. This requirement does not apply to dilution air samples, since they do not require secondary impingers, or to samples in which the concentrations approach the limit of detection.

(d) Component description, CFV-EFC-CVS. The CVS sample system is identical to the system described in paragraph (c) of this section, plus includes a means of electronically measuring the CVS flow rate, and electronic mass flow controllers for the methanol and formaldehyde sample lines. The EFC sample system shall conform to all of the requirements listed in paragraph (c), except that the methanol and formaldehyde samples must both be drawn from a static probe. It also must comply with the following additional requirements:

(1) The ratio of the CVS mass flow rate to the sample mass flow rate shall not deviate from the design ratio by more than ±5 percent. (The volumetric sample flow rate shall be varied inversely with the square root of the bulk stream temperature.)

(2) Flow meters to totalize sample volumes for methanol and/or formaldehyde samples shall meet the accuracy specifications of §86.120. Total sample volumes may be obtained from the flow controllers, provided that the controllers meet the accuracy specifications of §86.120.

[56 FR 25760, June 5, 1991, as amended at 59 FR 48505, Sept. 21, 1994; 60 FR 34336, June 30, 1995]

§86.110-94 Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate emissions measurements.

Section 86.110-94 includes text that specifies requirements that differ from §86.110-90. Where a paragraph in §86.110-90 is identical and applicable to §86.110-94, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.110-90.” Where a corresponding paragraph of §86.110-90 is not applicable, this is indicated by the statement “[Reserved].”

(a) General. The exhaust gas sampling system described in this paragraph is designed to measure the true mass of both gaseous and particulate emissions in the exhaust of either diesel-cycle or Otto-cycle light-duty vehicles and light-duty trucks. This system utilizes the CVS concept (described in §86.109) of measuring mass emissions. The mass of gaseous emissions is determined from the sample concentration and total flow over the test period. The mass of particulate emissions is determined from a proportional mass sample collected on a filter and from the total flow over the test period. General requirements are as follows:

(1) This sampling system requires the use of a PDP-CVS, CFV-CVS (or a CFV-EFC-CVS), sample system with heat exchanger connected to a dilution tunnel. The heat exchanger is not required for the CFV-CVS or EFC-CFV-CVS if electronic flow controllers are used to maintain proportionality for the particulate sample. Figure B94-5 is a schematic drawing of the PDP system. Figure B94-6 is a schematic drawing of the CFV-CVS system. (Methanol-fueled Otto-cycle vehicles may be tested using this test equipment, without measuring particulate emissions.)

(2) Bag, continuous HFID (required for petroleum-fueled diesel-cycle and optional for methanol-fueled, natural gas-fueled and liquefied petroleum gas-fueled diesel-cycle vehicles), and particulate sampling capabilities as shown in Figure B94-5 (or Figure B94-6) are required to provide both gaseous and particulate emissions sampling capabilities from a single system.

(3) Petroleum-fueled diesel-cycle vehicles require a heated flame ionization detector (HFID) (375°±20°F (191°±11°C)) sample for total hydrocarbon (THC) analysis. The HFID sample must be taken directly from the diluted exhaust stream through a heated probe in the dilution tunnel.

(4) Methanol-fueled vehicles require the use of a heated flame ionization detector (HFID) (235°±15°F (113°±8°C)) for hydrocarbon analysis. With an HFID, the hydrocarbon analysis can be made on the bag sample and the methanol and formaldehyde analyses are performed on the samples collected for these purposes (Figures B94-2 and B94-3).

Note:

For 1990 through 1994 model year methanol-fueled vehicles, methanol and formaldehyde sampling may be omitted provided the bag sample is analyzed using a HFID calibrated with methanol.

(5) For methanol-fueled vehicles, the vehicle tailpipe-to-dilution tunnel connection shall be made by:

(i) A tailpipe to dilution tunnel duct of unrestricted length maintained at a temperature above the dew point of the mixture, but below 250°F (121°C) through heating and cooling as required; or

(ii) Using a short duct (up to 12 feet long) constructed of smooth wall pipe with a minimum of flexible sections maintained at a temperature above the dew point of the mixture, but below 250°F (121°C) prior to the test and during breaks in testing (insulation may remain in place and or heating may occur during the testing provided the maximum temperature is not exceeded); or

(iii) Using smooth wall duct less than five feet long with no required heating. A maximum of two short flexible connectors are allowed under this option; or

(iv) By omitting the duct and performing the exhaust gas dilution function at the vehicle tailpipe exit.

(6) For natural gas-fueled and liquefied petroleum gas-fueled diesel vehicles either a heated flame ionization detector (HFID) [375°±20°F (191°±11°C)] or a non-heated flame ionization detector may be used for hydrocarbon analysis.

(7) Since various configurations can produce equivalent results, exact conformance with these drawings is not required. Additional components such as instruments, valves, solenoids, pumps, and switches may be used to provide additional information and coordinate the functions of the component systems.

(8) Other sampling systems may be used if shown to yield equivalent or superior results and if approved in advance by the Administrator.

(b) Component description - petroleum-fueled, natural gas-fueled and liquefied petroleum gas-fueled vehicles. The components necessary for petroleum-fueled, natural gas-fueled and liquefied petroleum gas-fueled vehicle exhaust sampling shall meet the following requirements:

(1) The PDP-CVS, Figure B94-5, shall contain a proportional particulate sampling system, and shall conform to all of the requirements listed for the exhaust gas PDP-CVS (§86.109(b)), with one exception: a flow rate of sufficient volume is required to maintain the diluted exhaust stream, from which the particulate sample flow is taken, at a temperature of 125°F (52°C) or less.

(2) The CFV sample system, Figure B94-6, shall contain a proportional particulate sampling system, and shall conform to all of the requirements listed for the exhaust gas CFV sample system (§86.109(c)), except for the following:

(i) A flow rate of sufficient volume is required to maintain the diluted exhaust stream, from which the particulate sample flow is taken, at a temperature of 125°F (52°C) or less.

(ii) If a constant volume particulate sample is collected, a heat exchanger is required.

(iii) If a heat exchanger is used, the gas mixture temperature, measured at a point immediately ahead of the critical flow venturi, shall be within ±20°F (11°C) of the designed operating temperature at the start of the test. The gas mixture temperature variation from its value at the start of the test shall be limited to ±20°F (11°C) during the entire test. The temperature measuring system shall have an accuracy and precision of ±2°F (1.1°C).

(iv) The cyclonic separator is optional.

(3) For gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled Otto-cycle and petroleum-fueled, natural gas- fueled and liquefied petroleum gas-fueled diesel-cycle vehicles, the transfer of heat from the vehicle exhaust gas shall be minimized between the point where it leaves the vehicle tailpipe(s) and the point where it enters the dilution tunnel airstream. To accomplish this, a short length (not more than 12 feet (365 cm) if uninsulated, or not more than 20 feet (610 cm) if insulated) of smooth stainless steel tubing from the tailpipe to the dilution tunnel is required. This tubing shall have a maximum inside diameter of 4.0 inches (10.2 cm). Short sections of flexible tubing at connection points are allowed.

(4) The vehicle exhaust shall be directed downstream at the point where it is introduced into the dilution tunnel.

(5) The dilution air shall be between 68°F (20°C) and 86°F (30°C) during the test.

(6) The dilution tunnel shall be:

(i) Sized to permit development of turbulent flow (Reynolds No. >>4000) and complete mixing of the exhaust and dilution air between the mixing orifice and each of the two sample probes (i.e., the particulate probe and the heated THC sample probe). It is recommended that uniform mixing be demonstrated by the user.

(ii) At least 8.0 inches (20.3 cm) in diameter.

(iii) Constructed of electrically conductive material which does not react with the exhaust components.

(iv) Grounded.

(7) The temperature of the diluted exhaust stream inside of the dilution tunnel shall be sufficient to prevent water condensation. However, the sample zone dilute exhaust temperature shall not exceed 125°F (52°C) at any time during the test.

(8) The particulate sample probe shall be:

(i) Installed facing upstream at a point where the dilution air and exhaust are well mixed (i.e., near the tunnel centerline, approximately 10 tunnel diameters downstream from the point where the exhaust enters the dilution tunnel).

(ii) Sufficiently distant (radially) from the THC probe (when the THC probe is required) so as to be free from the influence of any wakes or eddies produced by the THC probe.

(iii) 0.5 inch (1.27 cm) minimum inside diameter.

(iv) The distance from the sampling tip to the filter holder shall be at least 5 probe diameters (for filters located inside of the tunnel), but not more than 40.0 inches (102 cm) for filters located outside of the dilution tunnel.

(v) Free from sharp bends.

(vi) Configured so that a clean particulate filter (including back-up filter) can be selected simultaneously with the selection of an empty gaseous emissions bag.

(9) The flow rate through the particulate probe shall be maintained to a constant value within ±5 percent of the set flow rate.

(10) The particulate sample pump shall be located sufficiently distant from the dilution tunnel so that the inlet gas temperature is maintained at a constant temperature (±5.0°F (2.8°C)).

(11) The gas meters or flow instrumentation shall be located sufficiently distant from the tunnel so that the inlet gas temperature remains constant (±5.0°F (2.8°C)).

(12) The THC probe (when the THC probe is required) shall be:

(i) Installed facing upstream at a point where the dilution air and exhaust are well mixed (i.e., approximately 10 tunnel diameters downstream from the point where the exhaust enters the dilution tunnel).

(ii) Sufficiently distant (radially) from the particulate probe so as to be free from the influence of any wakes or eddies produced by the particulate probe.

(iii) Heated and insulated over the entire length to maintain a 375°±20°F (191°±11°C) wall temperature.

(iv) 0.19 in. (0.48 cm) minimum inside diameter.

(13) It is intended that the THC probe be free from cold spots (i.e., free from spots where the probe wall temperature is less than 355°F). This will be determined by a temperature sensor located on a section of the probe wall outside of the dilution tunnel. The temperature sensor shall be insulated from any heating elements on the probe. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(14) The dilute exhaust gas flowing in the THC sample system shall be:

(i) At 375°F±10°F (191°C±6°C) immediately before the heated filter. This will be determined by a temperature sensor located immediately upstream of the filter. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(ii) At 375°F±10°F (191°C ±6°C) immediately before the HFID. This will be determined by a temperature sensor located at the exit of the heated sample line. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(15) It is intended that the dilute exhaust gas flowing in the THC sample system be between 365°F and 385°F (185°C and 197°C).

(c) Component description - methanol-fueled vehicles. The components necessary for methanol-fueled vehicle exhaust sampling shall meet the following requirements:

(1) The PDP-CVS, Figure B94-5, shall contain a proportional particulate sampling system, and shall conform to all of the requirements listed for the exhaust gas PDP-CVS (§86.109), with one exception: a flow rate of sufficient volume is required to maintain the diluted exhaust stream, from which the particulate sample flow is taken, at a temperature of 125°F (52°C) or less.

(2) The CFV-CVS sample system, Figure B94-6, shall contain a proportional particulate sampling system, and shall conform to all of the requirements listed for the exhaust gas CFV sample system (§86.109), except for the following:

(i) A flow rate of sufficient volume is required to maintain the diluted exhaust stream, from which the particulate sample flow is taken, at a temperature of 125°F (52°C) or less.

(ii) If a constant volume particulate sample is collected, a heat exchanger is required.

(iii) If a heat exchanger is used, the gas mixture temperature, measured at a point immediately ahead of the critical flow venturi, shall be within ±20°F (11°C) of the designed operating temperature at the start of the test. The gas mixture temperature variation from its value at the start of the test shall be limited to ±20°F (11°C) during the entire test. The temperature measuring system shall have an accuracy and precision of ±2°F (1.1°C).

(iv) The cyclonic separator is optional.

(3) The EFC-CFV-CVS sample system shall conform to all of the requirements listed for the exhaust gas EFC sample system (§86.109) with three exceptions:

(i) A flow rate of sufficient volume is required to maintain the diluted exhaust stream, from which the particulate sample flow is taken, at a temperature of 125°F (52°C) or less.

(ii) A proportional particulate sample shall be collected using an electronic flow controller that meets the performance criteria listed in §86.109 for methanol and formaldehyde EFC systems.

(iii) The cyclonic separator is optional.

(4) Losses of methanol due to condensation of water in the duct connecting the vehicle tail pipe to the dilution tunnel must be eliminated. This may be accomplished by:

(i) The use of a duct of unrestricted length maintained at a temperature above the maximum dew point of the exhaust, but below 250°F (121°C), through heating and cooling as required; or

(ii) The use of a short duct (up to 12 feet long) constructed of smooth wall pipe with a minimum of flexible sections maintained at a temperature above the maximum dew point of the exhaust, but below 250°F (121°C), prior to the test and during breaks in testing (insulation may remain in place and/or heating may occur during testing provided maximum temperature is not exceeded); or

(iii) Using smooth wall duct less than five feet long with no required heating. A maximum of two short flexible connectors are allowed under this option; or

(iv) Omitting the duct and performing the exhaust gas dilution function at the vehicle tailpipe exit.

(5) The vehicle exhaust shall be directed downstream at the point where it is introduced into the dilution tunnel.

(6) The dilution air shall be between 68°F (20°C) and 86°F (30°C) during the test (unless the requirements of §86.109-94(b)(4) are also met).

(7) The dilution tunnel shall be:

(i) Sized to permit development of turbulent flow (Reynold's No. >>4000) and complete mixing of the exhaust and dilution air between the mixing orifice and the particulate sample probe. It is recommended that uniform mixing be demonstrated by the user.

(ii) At least 8.0 inches (20.3 cm) in diameter.

(iii) Constructed of electrically conductive material which does not react with the exhaust components.

(iv) Grounded.

(8) The temperature of the diluted exhaust stream inside of the dilution tunnel shall be sufficient to prevent water condensation. However, the sample zone dilute exhaust temperature shall not exceed 125°F (52°C) at any time during the test.

(9) The particulate sample probe shall be:

(i) Installed facing upstream at a point where the dilution air and exhaust are well mixed (i.e., near the tunnel centerline, approximately 10 tunnel diameters downstream from the point where the exhaust enters the dilution tunnel).

(ii) Sufficiently distant (radially) from the THC probe so as to be free from the influence of any wakes or eddies produced by the THC probe.

(iii) 0.5 inch (1.27 cm) minimum inside diameter.

(iv) The distance from the sampling tip to the filter holder shall be at least five probe diameters (for filters located inside the tunnel), but not more than 40.0 inches (102 cm) for filters located outside of the dilution tunnel.

(v) Free from sharp bends.

(vi) Configured so that a clean particulate filter (including back up filter) can be selected simultaneously with the selection of an empty gaseous emissions bag.

(10) The flow rate through the particulate probe shall be maintained to a constant value within ±5 percent of the set flow rate.

(11) The particulate sample pump shall be located sufficiently distant from the dilution tunnel so that the inlet gas temperature is maintained at a constant temperature (±5.0°F (2.8°C)).

(12) The gas meters or flow instrumentation shall be located sufficiently distant from the tunnel so that the inlet gas temperature remains constant (±5.0°F (2.8°C)).

(13) The hydrocarbon probe shall be:

(i) Installed facing upstream at a point where the dilution air and exhaust are well mixed (i.e., approximately ten tunnel diameters downstream from the point where the exhaust enters the dilution tunnel).

(ii) Sufficiently distant (radially) from the particulate probe so as to be free from the influence of any wakes of eddies produced by the particulate probe.

(iii) Heated and insulated over the entire length to maintain a wall temperature more than 5°F (3°C) above the maximum dew point of the sample, but below 250°F (121°C).

(iv) 0.19 in. (0.48 cm) minimum inside diameter.

(14) It is intended that the THC probe be free from cold spots (i.e., free from cold spots where the probe wall temperature is less than 5°F (3°C) above the maximum dew point of the sample.) This will be determined by a temperature sensor located on a section of the probe wall outside of the dilution tunnel. The temperature sensor shall be insulated from any heating elements on the probe. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(15) The dilute exhaust gas flowing in the hydrocarbon sample system shall be:

(i) At 235°F ±15°F (113°C ±8°C) immediately before the heated filter. This will be determined by a temperature sensor located immediately upstream of the filter. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(ii) At 235° ±15°F (113°C ±8°C) immediately before the HFID. This will be determined by a temperature sensor located at the exit of the heated sample line. The sensor shall have an accuracy and precision of ±2°F (1.1°C).

(16) It is intended that the dilute exhaust gas flowing in the hydrocarbon sample system between 220°F and 250°F (105°C and 121°C).

(17) For methanol-fueled vehicles, bag sampling procedures for the measurement of hydrocarbons as described in §86.109 may be employed.

(d) Filters, particulate sampling. Use fluorocarbon-coated glass fiber filters or fluorocarbon-based (membrane) filters to collect particulate matter, as follows:

(1) Use primary and back-up test filters as follows for particulate measurements:

(i) During each phase of the UDDS, sample dilute exhaust simultaneously with paired primary and back-up test filters.

(ii) Position the back-up filter holder 3 to 4 inches downstream of the primary filter holder.

(iii) Determine the net weight of particulate material collected on each primary test filter and each back-up test filter using the procedure described in §86.139.

(iv) Determine a ratio of net weights using the following formula:

(v) If the ratio is greater than 0.95, base the particulate emission calculations on the net weight of the primary filter only.

(vi) If the ratio is less than 0.95, base the particulate emission calculations on the combined net weights of the back-up test filter and the primary test filter.

(2) The particulate filter must have a 47 mm diameter (37 mm stain area).

[56 FR 25767, June 5, 1991, as amended at 59 FR 48505, Sept. 21, 1994; 60 FR 34342, June 30, 1995; 79 FR 23692, Apr. 28, 2014]

§86.111-94 Exhaust gas analytical system.

Section 86.111-94 includes text that specifies requirements that differ from §86.111-90. Where a paragraph in §86.111-90 is identical and applicable to §86.111-94, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.111-90.” Where a corresponding paragraph of §86.111-90 is not applicable, this is indicated by the statement “[Reserved].”

(a) Schematic drawings. Figure B94-7 is a schematic drawing of the exhaust gas analytical system for samples from bag sampling systems for analysis of total hydrocarbon (THC) (hydrocarbon plus methanol in the case of methanol-fueled vehicles), methane (CH₄) (for vehicles subject to the NMHC and NMHCE standards), carbon monoxide (CO), carbon dioxide (CO₂), and oxides of nitrogen (NO_X). The schematic diagram of the continuous THC analysis train (and for THC plus methanol for methanol-fueled diesel-cycle vehicles) is shown as part of Figure B94-5 (or Figure B94-6). Since various configurations can produce accurate results, exact conformance with either drawing is not required. Additional components such as instruments, valves, solenoids, pumps, and switches may be used to provide additional information and coordinate the functions of the component systems.

(b) Major component description. The exhaust gas analytical system, Figure B94-7, consists of a flame ionization detector (FID) (heated, 235° ±15°F (113° ±8°C) for methanol-fueled vehicles) for the determination of THC, a methane analyzer (consisting of a gas chromatograph combined with a FID) for the determination of CH₄, non-dispersive infrared analyzers (NDIR) for the determination of CO and CO₂, a chemiluminescence analyzer (CL) for the determination of NO_X, and an analyzer meeting the requirements specified in 40 CFR 1065.275 for the determination of N₂O. A heated flame ionization detector (HFID) is used for the continuous determination of THC from petroleum-fueled diesel-cycle vehicles (may also be used with methanol-fueled diesel-cycle vehicles), Figure B94-5 (or B94-6). The analytical system for methanol consists of a gas chromatograph (GC) equipped with a flame ionization detector. The analysis for formaldehyde is performed using high-pressure liquid chromatography (HPLC) of 2,4-dinitrophenylhydrazine (DNPH) derivatives using ultraviolet (UV) detection. The exhaust gas analytical system shall conform to the following requirements:

(1) The CL requires that the nitrogen dioxide present in the sample be converted to nitric oxide before analysis. Other types of analyzers may be used if shown to yield equivalent results and if approved in advance by the Administrator.

(2) The carbon monoxide (CO) NDIR analyzer may require a sample conditioning column containing CaSO₄, or indicating silica gel to remove water vapor, and containing ascarite to remove carbon dioxide from the CO analysis stream.

(i) If CO instruments which are essentially free of CO₂ and water vapor interference are used, the use of the conditioning column may be deleted, see §§86.122 and 86.144.

(ii) A CO instrument will be considered to be essentially free of CO₂ and water vapor interference if its response to a mixture of 3 percent CO₂ in N₂ which has been bubbled through water at room temperature produces an equivalent CO response, as measured on the most sensitive CO range, which is less than l percent of full scale CO concentration on ranges above 300 ppm full scale or less than 3 ppm on ranges below 300 ppm full scale, see §86.122.

(3) For petroleum-fueled diesel vehicles (and if selected, for methanol-fueled, natural gas-fueled and liquefied petroleum gas-fueled diesel vehicles) a continuous hydrocarbon sample shall be measured using a heated analyzer train as shown in Figure B90-5 (or B90-6). The train shall include a heated probe, a heated continuous sampling line, a heated particulate filter and a heated hydrocarbon instrument (HFID) complete with heated pump, filter and flow control system.

(i) The response time of this instrument shall be less than 1.5 seconds for 90 percent of full scale response.

(ii) The continuous THC sample system may use an “overflow” zero and span system; see §86.140-82(b)(4). In this type of system (figures B82-3A and B82-4A), zero or span gas is introduced into the heated sample line at a flow rate that exceeds the sample flow rate to the HFID. The excess gas overflows the sample probe into the dilution tunnel. This method assures that the reference gas enters HFID in the same concentration as the injected reference gas and at the same rate as the sample exhaust gas. In addition to zero and span checks, it may also be used to calibrate the THC analyzer per §86.121-82(b). The overflow gas flow rate into the sample line shall be greater than 125 percent of the HFID flow rate with the CVS blower operating. A lower flow rate may be used if it has been experimentally shown to produce equivalent results and current documentation is maintained. The overflow gases shall enter the heated sample line as close as practicable to the outside surface of the dilution tunnel.

(iii) No other analyzers may draw a sample from the continuous THC sample probe, line, or system, unless a common sample pump is used of all analyzers and the single sample line system design reflects good engineering practice.

(iv) Sample transport time from sampling point to inlet of instrument shall be less than 4 seconds.

(v) For petroleum-fueled, natural gas-fueled and liquefied petroleum gas-fueled diesel vehicles, the sample line and filter shall be heated to maintain a sample gas temperature of 375° ±10°F (191° ±6°C) before the filter and before the HFID.

(vi) For methanol-fueled diesel-cycle vehicles, the sample line and filter shall be heated to maintain a sample gas temperature of 235°±15°F (113°±8°C) before the filter and before the HFID.

(vii) Using a methane analyzer consisting of a gas chromatograph combined with a FID, measure methane according to SAE J1151 (incorporated by reference in §86.1).

(c) Other analyzers and equipment. Other types of analyzers and equipment may be used if shown to yield equivalent or superior results and if approved in advance by the Administrator.

[56 FR 25771, June 5, 1991, as amended at 58 FR 33209, June 16, 1993; 59 FR 48505, Sept. 21, 1994; 59 FR 50073, Sept. 30, 1994; 75 FR 25677, May 7, 2010; 77 FR 63152, Oct. 15, 2012; 79 FR 23693, Apr. 28, 2014]

§86.112-91 Weighing chamber (or room) and microgram balance specifications.

(a) Ambient conditions- (1) Temperature. The temperature of the chamber in which the particulate filters are conditioned and weighed shall be maintained to within ±10°F (6°C) of a set point between 68°F (20°C) and 86°F (30°C) during all filter conditioning and filter weighing. A continuous recording of the temperature is required.

(2) Humidity. The relative humidity of the chamber in which the particulate filters are conditioned and weighed shall be maintained to within ±10 percent of a set point between 30 and 70 percent during all filter conditioning and filter weighing. A continuous recording of the temperature is required.

(3) The environment shall be free from any ambient contaminants (such as dust) that would settle on the particulate filters during their stabilization.

(4) It is required that two unused reference filters remain in the weighing room at all times in covered (to reduce dust contamination) but unsealed (to permit humidity exchange) petri dishes. These reference filters shall be placed in the same general area as the sample filters. These reference filters shall be weighed within 4 hours of, but preferably just prior to, the pre- and post-test sample filter weighings.

(5) If the weight of either of the reference filters changes between pre- and post-test sample filter weighings by more than ±2.0 percent of the test average primary filter loading (recommended minimum of 0.5 milligrams) or ±0.010 milligrams, whichever is greater, then the post-test sample filter weights are invalid. However, the post-test weighing procedure can be repeated to obtain valid weights within the time limits as specified in §86.139.

(6) The reference filters shall be changed at least once per month, but never between pre- and post-test weighings of a given sample filter. The reference filters shall be the same size and material as the sample filters.

(b) Microgram balance specifications. The microgram balance used to determine the weights of all filters shall have a precision (standard deviation) and a readability of one microgram.

(c) Other procedures and equipment. Other procedures and equipment may be used if shown to yield equivalent or superior results and if approved in advance by the Administrator.

[56 FR 25773, June 5, 1991]

§86.113-04 Fuel specifications.

This section includes text that specifies requirements that differ from §86.113-94. Where a paragraph in §86.113-94 is identical and applicable to this section, this will be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.113-94.”.

(a) Gasoline fuel.(1) Gasoline meeting the following specifications, or substantially equivalent specifications approved by the Administrator, must be used for exhaust and evaporative testing:

(2) Manufacturers may use California test fuels, as follows:

(i) [Reserved]

(ii) For model year 2015 and later, manufacturers may certify 50-state Tier 2 vehicles based on testing used to meet California's LEV III standards, subject to the following provisions:

(A) Manufacturers may perform exhaust and evaporative emission tests using California Phase 2 gasoline or California LEV III gasoline. The Administrator may use or require the use of test fuel meeting the specifications in paragraph (a)(1) of this section for confirmatory testing, selective enforcement auditing and in-use testing.

(B) All evaporative testing with California fuel must be conducted with temperatures meeting the specifications adopted by the California Air Resources Board.

(C) The vehicles must also meet exhaust and evaporative emission standards at high-altitude conditions as specified in §§86.1811-17 and 86.1813-17, except that testing is based on the fuel specified in paragraph (a)(1) of this section.

(D) The vehicle must meet the applicable cold temperature standards using test fuel specified for cold temperature testing in §86.213.

(3)(i) Unless otherwise approved by the Administrator, gasoline representative of commercial gasoline that will be generally available through retail outlets must be used in service accumulation. Unless otherwise approved by the Administrator, where the vehicle is to be used for evaporative emission durability demonstration, such fuel must contain ethanol as required by §86.1824-08(f)(1).

(ii) Unless otherwise approved by the Administrator, the octane rating of the gasoline used must be no higher than 1.0 Retail octane number above the lowest octane rating that meets the fuel grade the manufacturer will recommend to the ultimate purchaser for the relevant production vehicles. If the manufacturer recommends a Retail octane number rather than a fuel grade, then the octane rating of the service accumulation gasoline can be no higher than 1.0 Retail octane number above the recommended Retail octane number. The service accumulation gasoline must also have a minimum sensitivity of 7.5 octane numbers, where sensitivity is defined as the Research octane number minus the Motor octane number.

(iii) The Reid Vapor Pressure of the gasoline used must be characteristic of the motor fuel used during the season in which the service accumulation takes place.

(4) The specification range of the gasoline to be used under this paragraph (a) must be reported in accordance with §§86.094-21(b)(3) and 86.1844-01.

(b)-(g) [Reserved]. For guidance see §86.113-94.

[65 FR 6848, Feb. 10, 2000, as amended at 75 FR 25678, May 7, 2010; 79 FR 23693, Apr. 28, 2014; 86 FR 34365, Jun. 29, 2021; 89 FR 28156, Apr. 18, 2024]

§86.113-15 Fuel specifications.

(a) Gasoline fuel. This paragraph (a) describes how to transition to an ethanol-blend test fuel for vehicles certified under subpart S of this part. You may use the test fuels specified in §86.113-04(a) for vehicles that are not yet subject to testing with the new fuel. You may use the specified ethanol-blend test fuel anytime earlier than we specify as long as you use the corresponding procedures for measuring and calculating emission results. See 40 CFR 600.117 for special provisions that apply for emission measurements related to fuel economy and greenhouse gases. Manufacturers must certify using E10 test fuel as specified in 40 CFR part 1065, subpart H, and service accumulation fuel meeting applicable specifications as follows:

(1) Except as allowed under paragraph (a)(2) of this section, Use E10 test fuel to demonstrate compliance with the Tier 3 exhaust emission standards as specified in §86.1811 and 86.1816, and to demonstrate compliance with the Tier 3 evaporative emission standards as specified in §86.1813.

(2) You may use California test fuels to demonstrate compliance with Tier 3 emission standards as follows:

(i) For vehicles certified for 50-state sale, you may instead use California Phase 3 gasoline (E10) as adopted in California's LEV III program for exhaust emission testing. Through model year 2019, we will also use this E10 fuel for any low-altitude exhaust emission testing with such vehicles. Starting in model year 2020, we may use test fuel meeting either California Phase 3 gasoline (E10) or the gasoline (E10) test fuel specified in this paragraph (a). For cold temperature testing and for exhaust emission tests at high-altitude conditions, you may certify vehicles through model year 2019 based on testing with the gasoline (E0) test fuel specified in §86.113-04(a); for such vehicles, we may use test fuel meeting either the gasoline (E0) test fuel specified in §86.113-04(a) or the gasoline (E10) test fuel specified in this paragraph (a).

(ii) For vehicles that were certified to SULEV exhaust emission standards with a 150,000 mile useful life under California's LEV II program and that are eligible to use that carryover data for continued certification, you may use that carryover data to demonstrate compliance with the exhaust emission standards that apply for Bin 30 vehicles under §86.1811-17 for model years 2015 through 2019. The test fuel specifications that applied for the original emission measurements under the LEV II program also apply for any additional exhaust testing under the Tier 3 program, including confirmatory testing, selective enforcement auditing, and in-use testing. For vehicles certified under this paragraph (a)(2)(ii), use the E10 test fuel specified in 40 CFR 1065.710 for cold temperature testing and high-altitude testing.

(iii) For vehicles certified for 50-state sale, you may instead use California test fuel for evaporative emission testing as follows:

(A) If you originally certified vehicles in California in model year 2015 or 2016 to PZEV standards with California Phase 2 gasoline, you may use that data with carryover vehicles to certify to the Tier 3 evaporative emission standards through model year 2019. We will use this same fuel to measure diurnal, hot soak, running loss, and SHED rig emissions at low-altitude conditions for such vehicles. For refueling, spitback, and high-altitude testing, you may use test fuel meeting either the gasoline (E0) test fuel specified in §86.113-04(a) or the gasoline (E10) test fuel specified in this paragraph (a); we may use either of the specified fuels for our testing. For leak testing, you must use the gasoline (E10) test fuel specified in this paragraph (a).

(B) If you certify vehicles to LEV III standards with California Phase 3 gasoline (E10), you may use that collection of data to certify to the Tier 3 evaporative emission standards. Through model year 2019, we will use this same fuel to measure diurnal, hot soak, running loss, SHED rig, and canister bleed emissions (as appropriate) at low-altitude conditions; starting in model year 2020, we may use either California Phase 3 gasoline (E10) or the gasoline (E10) test fuel specified in this paragraph (a) for our testing with such vehicles. For refueling, spitback, high-altitude, and leak testing, you must use the gasoline (E10) test fuel specified in this paragraph (a), except that you may instead use the gasoline (E0) test fuel specified in §86.113-04(a) for model year 2015 and 2016; we will use your selected fuel for our testing. Note that you may no longer certify vehicles to the Tier 3 standards based on California's rig-testing procedures after model year 2021, as described in §86.1813-17(g).

(C) For evaporative emission testing with California test fuels, perform tests based on the test temperatures specified by the California Air Resources Board.

(3) Except as specified in paragraph (a)(2)(iii) of this section and in this paragraph (a)(3), use E10 test fuel to demonstrate compliance with the refueling and spitback emission standards for any vehicles that must be certified to meet the diurnal plus hot soak standards with E10 test fuel under paragraphs (a)(1) and (2) of this section. You may delay using E10 test fuel until model year 2022 for incomplete heavy-duty vehicles not certified to refueling emission standards.

(4) If a vehicle uses E10 test fuel for evaporative emission testing and E0 is the applicable test fuel for exhaust emission testing, exhaust measurement and reporting requirements apply over the course of the evaporative emission test, but the vehicle need not meet the exhaust emission standards during the evaporative emission test run.

(5) For service accumulation, use a commercially available fuel, subject to the additional specification in §86.1824-08(f) for evaporative emissions.

(b) Diesel fuel. For diesel-fueled engines, use the ultra low-sulfur diesel fuel specified in 40 CFR 1065.703.

(c) Other fuels. For fuels other than gasoline or diesel fuel, use the appropriate test fuel as specified in 40 CFR part 1065, subpart H.

[79 FR 23694, Apr. 28, 2014; 89 FR 28156, Apr. 18, 2024]

§86.113-27 Fuel Specifications.

Use the fuels specified in 40 CFR part 1065 to perform valid tests, as follows:

(a) For service accumulation, use the test fuel or any commercially available fuel that is representative of the fuel that in-use vehicles will use.

(b) For diesel-fueled engines, use the ultra low-sulfur diesel fuel specified in 40 CFR part 1065.703 for emission testing.

(c) The following fuel requirements apply for gasoline-fueled engines:

(1) Use the appropriate E10 fuel specified in 40 CFR part 1065.710(b) to demonstrate compliance with all exhaust, evaporative, and refueling emission standards under subpart S of this part.

(2) For vehicles certified for 50-state sale, you may instead use California Phase 3 gasoline (E10) as adopted in California's LEV III program as follows:

(i) You may use California Phase 3 gasoline (E10) as adopted in California's LEV III program for exhaust emission testing.

(ii) If you certify vehicles to LEV III evaporative emission standards with California Phase 3 gasoline (E10), you may use that collection of data to certify to evaporative emission standards. For evaporative emission testing with California test fuels, perform tests based on the test temperatures specified by the California Air Resources Board. Note that this paragraph (c)(2)(ii) does not apply for refueling, spitback, high-altitude, or leak testing.

(iii) If you certify using fuel meeting California's specifications, we may perform testing with E10 test fuel meeting either California or EPA specifications.

(d) Interim test fuel specifications apply for model years 2027 through 2029 as described in 40 CFR 600.117.

(e) Additional test fuel specifications apply as specified in subpart S of this part.

[89 FR 28156, Apr. 18, 2024]

§86.113-94 Fuel specifications.

(a) [Reserved]

(b) Petroleum diesel test fuel. (1) The petroleum fuels employed for testing diesel vehicles shall be clean and bright, with pour and cloud points adequate for operability. The petroleum diesel fuel may contain nonmetallic additives as follows: Cetane improver, metal deactivator, antioxidant, dehazer, antirust, pour depressant, dye, dispersant and biocide. Fuels specified for emissions testing are intended to be representative of commercially available in-use fuels.

(2) A diesel fuel designated as “Type 2-D” grade meeting the following specifications, or substantially equivalent specifications approved by the Administrator, must be used for exhaust emission testing:

(3) A diesel fuel designated as “Type 2-D” grade meeting the following specifications, or substantially equivalent specifications approved by the Administrator, must be used for service accumulation:

(4) Other petroleum distillate fuels may be used for testing and service accumulation provided:

(i) They are commercially available; and

(ii) Information, acceptable to the Administrator, is provided to show that only the designated fuel would be used in customer service; and

(iii) Use of a fuel listed under paragraphs (b)(2) and (b)(3) of this section would have a detrimental effect on emissions or durability; and

(iv) Written approval from the Administrator of the fuel specifications is provided prior to the start of testing.

(5) The specification range of the fuels to be used under paragraphs (b)(2), (b)(3) and (b)(4) of this section shall be reported in accordance with §86.094-21(b)(3) or §86.1844-01 as applicable.

(c) Methanol fuel. (1) Methanol fuel used for exhaust and evaporative emission testing and in service accumulation shall be representative of commercially available methanol fuel and shall consist of at least 50 percent methanol by volume.

(i) Manufacturers shall recommend the methanol fuel to be used for testing and service accumulation.

(ii) The Administrator shall determine the methanol fuel to be used for testing and service accumulation.

(2) Other methanol fuels may be used for testing and service accumulation provided:

(i) They are commercially available; and

(ii) Information, acceptable to the Administrator, is provided to show that only the designated fuel would be used in customer service; and

(iii) Use of a fuel listed under paragraph (c)(1) of this section would have a detrimental effect on emissions or durability; and

(iv) Written approval from the Administrator of the fuel specifications must be provided prior to the start of testing.

(3) The specification range of the fuels to be used under paragraphs (c)(1) and (c)(2) of this section shall be reported in accordance with §86.094-21(b)(3) or §86.1844-01 as applicable.

(d) [Reserved]

(e) Natural gas. (1) A natural gas fuel meeting the following specifications, or substantially equivalent specifications approved by the Administrator, must be used for exhaust and evaporative emission testing:

(2) The natural gas at ambient conditions must have a distinctive odor potent enough for its presence to be detected down to a concentration in air of not over one-fifth of the lower limit of flammability.

(3) Natural gas representative of commercially available natural gas fuel generally available through retail outlets shall be used in service accumulation for natural gas-fueled vehicles.

(4) A natural gas fuel meeting different specifications may be used for testing and service accumulation if all the following conditions are met:

(i) The alternate test fuel is commercially available.

(ii) Information acceptable to the Administrator is provided to show that only the designated fuel will be used in customer service.

(iii) The Administrator must provide advance written approval for the alternate test fuel.

(f) Liquefied petroleum gas fuel. (1) Liquefied petroleum gas fuel used for exhaust and evaporative emission testing and in service accumulation shall be commercially available liquefied petroleum gas fuel.

(i) Manufacturers shall recommend the liquefied petroleum gas fuel to be used for testing and service accumulation.

(ii) The Administrator shall determine the liquefied petroleum gas fuel to be used for testing and service accumulation.

(2) Other liquefied petroleum gas fuels may be used for testing and service accumulation provided:

(i) They are commercially available; and

(ii) Information, acceptable to the Administrator, is provided to show that only the designated fuel would be used in customer service; and

(iii) Written approval from the Administrator of the fuel specifications must be provided prior to the start of testing.

(3) The specification range of the fuel to be used under paragraphs (f)(1) and (2) of this section shall be measured in accordance with ASTM D2163 (incorporated by reference in §86.1).

(g) Fuels not meeting the specifications set forth in this section may be used only with the advance approval of the Administrator.

[59 FR 48506, Sept. 21, 1994, as amended at 60 FR 34342, June 30, 1995; 62 FR 47120, Sept. 5, 1997; 63 FR 24448, May 4, 1998; 64 FR 23921, May 4, 1999; 65 FR 8277, Feb. 18, 2000; 79 FR 23694, Apr. 28, 2014; 79 FR 36657, June 30, 2014]

§86.114-94 Analytical gases.

(a) Analyzer gases. (1) Gases for the CO and CO₂ analyzers shall be single blends of CO and CO₂ respectively using nitrogen as the diluent.

(2) Gases for the THC analyzer shall be:

(i) Single blends of propane using air as the diluent; and

(ii) Optionally, for response factor determination, single blends of methanol using air as the diluent.

(3) Gases for the methane analyzer shall be single blends of methane using air as the diluent.

(4) Gases for the NO_X analyzer shall be single blends of NO named as NO_X. with a maximum NO₂ concentration of 5 percent of the nominal value, using nitrogen as the diluent.

(5) Fuel for FIDs and HFIDs and the methane analyzer shall be a blend of 40 ±2 percent hydrogen with the balance being helium. The mixture shall contain less than one ppm equivalent carbon response. 98 to 100 percent hydrogen fuel may be used with advance approval by the Administrator.

(6) The allowable zero gas (air or nitrogen) impurity concentrations shall not exceed 1 ppm equivalent carbon response, 1 ppm carbon monoxide, 0.04 percent (400 ppm) carbon dioxide, and 0.1 ppm nitric oxide.

(7) “Zero grade air” includes artificial “air” consisting of a blend of nitrogen and oxygen with oxygen concentrations between 18 and 21 mole percent.

(8) The use of precision blending devices (gas dividers) to obtain the required calibration, as defined below, is acceptable, provided that the calibration curves they produce name a calibration gas within 2 percent of its certified concentration. This verification shall be performed at between 15 and 50 percent of the full scale concentration of the range and shall be included with each gas calibration incorporating a blending device. Alternative procedures to verify the validity of the analyzer calibration curves generated using a gas divider are acceptable provided the procedures are approved in advance by the Administrator.

(b) Calibration gases (not including methanol) shall be traceable to within one percent of NIST (formerly NBS) gas standards, or other gas standards which have been approved by the Administrator.

(c) Span gases (not including methanol) shall be accurate to within two percent of true concentration, where true concentration refers to NIST (formerly NBS) gas standards, or other gas standards which have been approved by the Administrator.

(d) Methanol in air gases used for response factor determination shall:

(1) Be traceable to within ±2 percent of NIST (formerly NBS) gas standards, or other standards which have been approved by the Administrator; and

(2) Remain within ±2 percent of the labeled concentration. Demonstration of stability shall be based on a quarterly measurement procedure with a precision of ±2 percent (two standard deviations), or other method approved by the Administrator. The measurement procedure may incorporate multiple measurements. If the true concentration of the gas changes by more than two percent, but less than ten percent, the gas may be relabeled with the new concentration.

[56 FR 25773, June 5, 1991, as amended at 60 FR 34342, June 30, 1995]

§86.115-78 EPA dynamometer driving schedules.

(a) The driving schedules for the Urban Dynamometer Driving Schedule, US06, SC03, and the New York City Cycles are specified in appendix I of this part. The driving schedules are defined by a smooth trace drawn through the specified speed vs. time relationships. They each consist of a distinct non-repetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates.

(b) The driver should attempt to follow the target schedule as closely as possible (refer to §86.128 for additional cycle driving instructions). The speed tolerance at any given time for these schedules, or for a driver's aid chart approved by the Administrator, are as follows:

(1) The upper limit is 2 mph (3.2 km/h) higher than the highest point on the trace within 1 second of the given time.

(2) The lower limit is 2 mph (3.2 km/h) lower than the lowest point on the trace within 1 second of the given time.

(3)(i) Speed variations greater than the tolerances (such as may occur during gear changes or braking spikes) are acceptable, provided they occur for less than 2 seconds on any occasion and are clearly documented as to the time and speed at that point of the driving schedule.

(ii) When conducted to meet the requirements of §86.129-94 or §86.153-98(d), up to three additional occurrences of speed variations greater than the tolerance are acceptable, provided they occur for less than 15 seconds on any occasion, and are clearly documented as to the time and speed at that point of the driving schedule.

(4) Speeds lower than those prescribed are acceptable, provided the vehicle is operated at maximum available power during such occurrences.

(5) When conducted to meet the requirements of §86.129-94, §86.132-96, §86.146-96, or §86.153-98(d), the speed tolerance shall be as specified above, except that the upper and lower limits shall be 4 mph (6.4 km/h).

(c) Figures B78-4(a) and B78-4(b) show the range of acceptable speed tolerances for typical points. Figure B78-4(a) is typical of portions of the speed curve which are increasing or decreasing throughout the 2-second time interval. Figure B78-4(b) is typical of portions of the speed curve which include a maximum or minimum value.

[42 FR 32954, June 28, 1977, as amended at 43 FR 52920, Nov. 14, 1978; 58 FR 16030, Mar. 24, 1993; 59 FR 16296, Apr. 6, 1994; 79 FR 23695, Apr. 28, 2014]

§86.116-94 Calibrations, frequency and overview.

(a) Calibrations shall be performed as specified in §86.117 through §86.126.

(b) At least yearly or after any maintenance which could alter background emission levels, evaporative enclosure background emission measurements shall be performed.

(c) At least monthly or after any maintenance which could alter calibration, the following calibrations and checks shall be performed:

(1) Calibrate the THC analyzers (both evaporative and exhaust instruments), methane analyzer, carbon dioxide analyzer, carbon monoxide analyzer, and oxides of nitrogen analyzer (certain analyzers may require more frequent calibration depending on particular equipment and uses).

(2) Calibrate the dynamometer. If the dynamometer receives a weekly performance check (and remains within calibration) the monthly calibration need not be performed.

(3) Perform an organic gas retention and calibration on the evaporative emissions enclosure (see §86.117-90(c)).

(4) Calibrate the gas meters or flow instrumentation used for providing total flow measurement for particulate sampling.

(5) Check the oxides of nitrogen converter efficiency.

(d) At least weekly or after any maintenance which could alter calibration, the following calibrations and checks shall be performed:

(1) [Reserved]

(2) Perform a CVS system verification, and

(3) Run a performance check on the dynamometer. This check may be omitted if the dynamometer has been calibrated within the preceding month.

(e) The CVS positive displacement pump or Critical Flow Venturi shall be calibrated following initial installation, major maintenance, or as necessary when indicated by the CVS system verification (described in §86.119).

(f) Sample conditioning columns, if used in the CO analyzer train, should be checked at a frequency consistent with observed column life or when the indicator of the column packing begins to show deterioration.

(g) The Administrator, upon request, may waive the requirement to comply with the specified methanol recovery tolerance (e.g., ±2 percent in §§86.117-90 and 86.119-90), and/or the specified methanol retention tolerance (e.g., ±4 percent in §86.117-90), and instead require compliance with higher tolerances (not to exceed ±6 percent for recoveries and ±8 for retention), provided that:

(1) The Administrator determines that compliance with these specified tolerances is not practically feasible; and

(2) The manufacturer makes information available to the Administrator which indicates that the calibration tests and their results are consistent with good laboratory practice, and that the results are consistent with the results of calibration testing conducted by the Administrator.

[56 FR 25774, June 5, 1991, as amended at 58 FR 58422, Nov. 1, 1993; 59 FR 33913, July 1, 1994; 60 FR 34342, June 30, 1995]

§86.117-96 Evaporative emission enclosure calibrations.

The calibration of evaporative emission enclosures consists of three parts: initial and periodic determination of enclosure background emissions (hydrocarbons and methanol); initial determination of enclosure internal volume; and periodic hydrocarbon and methanol retention check and calibration. Ethanol retention checks may be performed instead of methanol retention checks. Alcohol retentions may be omitted if no alcohol-fueled vehicles will be tested in the evaporative enclosure. For evaporative and refueling emission tests with ethanol-gasoline blends that have less than 25% ethanol by volume, if you account for ethanol with a mathematical adjustment as described in §86.1813-17(a)(1)(iv) instead of measuring ethanol, the testing specifications and diagnostic requirements in this part 86 that are specific to ethanol-gasoline blends do not apply. Alternate calibration methods may be used if shown to yield equivalent or superior results, and if approved in advance by the Administrator; specifically, more extreme temperatures may be used for determining calibration without affecting the validity of test results.

(a) Initial and periodic determination of enclosure background emissions. Prior to its introduction into service, annually thereafter, and after any repair that can affect the enclosure background emissions, the enclosure shall be checked to determine that it does not contain materials that will themselves emit hydrocarbons or methanol. When methanol as well as hydrocarbons are present in the evaporative enclosure, the HFID hydrocarbon concentration measurement includes the partial response of the HFID to methanol plus the hydrocarbons. Determination of the HFID response to methanol, §86.121, prior to its being placed in service is required for the determination of hydrocarbons. Proceed as follows:

(1) Prepare the enclosure. (i) Variable-volume enclosures may be operated in either latched or unlatched volume configuration, as described in paragraph (b)(1) of this section. Ambient temperatures shall be maintained at 96±3°F throughout the 4-hour period.

(ii) Fixed-volume enclosures may be operated with inlet and outlet flow streams either closed or open; if inlet and outlet flow streams are open, the air flowing into and out of the enclosure must be monitored in accordance with §86.107-96(a)(1)(i)(B). Ambient temperatures shall be maintained at 96±3°F throughout the 4-hour period.

(iii) For running loss enclosures ambient temperatures shall be maintained at 95±3°F throughout the 4-hour period. For running loss enclosures designed with a vent for makeup air, the enclosure shall be operated with the vent closed.

(2) The enclosure may be sealed and the mixing fan operated for a period of up to 12 hours before the 4-hour background sampling period begins.

(3) Zero and span (calibrate if required) the hydrocarbon analyzer.

(4) Prior to the background determination, purge the enclosure until a stable background hydrocarbon reading is obtained.

(5) Turn on the mixing blower (if not already on).

(6) Seal enclosure and measure background hydrocarbon concentration, background methanol, temperature, and barometric pressure.

These are the initial readings C_HCi, C_CH3_OHi, and P_Bi, T_i for the enclosure background determination.

(7) Allow the enclosure to stand undisturbed for four hours.

(8) Measure the hydrocarbon concentration on the same FID and the methanol level. These are the final concentrations, C_HCf and C_CH3_OHf. Also measure final temperature and barometric pressure.

(9) Calculate the mass change of methanol, hydrocarbons, and hydrocarbons plus methanol in the enclosure according to the equations in paragraph (d) of this section.

(i) Diurnal enclosures. The enclosure background emissions (hydrocarbons plus methanol) shall not be greater than 0.05g for the 4 hours.

(ii) Running loss enclosures. The enclosure background emissions (hydrocarbons plus methanol) shall not be greater than 0.2 grams for the 4 hours.

(b) Initial determination of enclosure internal volume. Prior to its introduction into service the enclosure internal volume shall be determined by the following procedure:

(1) Carefully measure the internal length, width and height of the enclosure, accounting for irregularities (such as braces) and calculate the internal volume. For variable-volume enclosures, latch the enclosure to a fixed volume when the enclosure is held at a constant temperature; this nominal volume shall be repeatable within ±0.5 percent of the reported value.

(2)-(3) [Reserved]

(c) Hydrocarbon and methanol (organic gas) retention check and calibration. The hydrocarbon and methanol (if the enclosure is used for methanol-fueled vehicles) retention check provides a check upon the calculated volume and also measures the leak rate. The enclosure leak rate shall be determined prior to its introduction into service, following any modifications or repairs to the enclosure that may affect the integrity of the enclosure, and at least monthly thereafter. The methanol retention check must be performed only upon initial installation and after major maintenance, consistent with good engineering judgment. If six consecutive monthly retention checks are successfully completed without corrective action, the enclosure leak rate may be determined quarterly thereafter as long as no corrective action is required.

(1) An enclosure to be used for the diurnal emission test (see §86.133-96) shall be calibrated according to the following procedure. Calibration for hydrocarbon and methanol may be conducted simultaneously or in sequential test runs.

(i) Zero and span (calibrate if required) the hydrocarbon analyzer.

(ii) Purge the enclosure until a stable background hydrocarbon reading is obtained.

(iii) Turn on the mixing blowers (if not already on).

(iv) [Reserved]

(v) Turn on the ambient temperature control system (if not already on) and adjust it for an initial temperature of 96°F (36°C). On variable-volume enclosures, latch the enclosure to the appropriate volume position for the set temperature. On fixed-volume enclosures close the outlet and inlet flow streams.

(vi) When the enclosure stabilizes at 96±3°F (36±2°C), seal the enclosure and measure background hydrocarbon concentration, background methanol, temperature, and barometric pressure. These are the initial readings C_HCi, C_CH3_OHi, T_i, and P_Bi for the enclosure calibration.

(vii) Inject into the enclosure 0.5 to 1.0 grams of pure methanol at a recommended temperature of at least 150°F (65°C) and/or 0.5 to 1.0 grams of pure propane at lab ambient temperature. The injected quantity may be measured by volume flow or by mass measurement. The method used to measure the quantity of methanol and propane must have an accuracy of ±0.5 percent of the measured value (less accurate methods may be used with the advance approval of the Administrator).

(viii) After a minimum of 5 minutes of mixing, analyze the enclosure atmosphere for hydrocarbon and methanol content, also record temperature and pressure. These measurements are the final readings for the enclosure calibration as well as the initial readings for the retention check.

(ix) To verify the enclosure calibration, calculate the mass of propane and the mass of methanol using the measurements taken in paragraphs (c)(1)(vi) and (viii) of this section. See paragraph (d) of this section. This quantity must be within ±2 percent of that measured in paragraph (c)(1)(vii) of this section for propane and ±5 percent for methanol. Evaluate long-term trends using good engineering judgment to minimize measurement bias. Keep records to document such evaluations and make them available to EPA upon request.

(x) For variable-volume enclosures, unlatch the enclosure from the nominal volume configuration. For fixed-volume enclosures, open the outlet and inlet flow streams.

(xi) Start cycling the ambient temperature from 96°F to 72°F and back to 96°F over a 24-hour period, according to the profile specified in §86.133-96 and appendix II of this part, within 15 minutes of sealing the enclosure.

(xii) At the completion of the 24-hour cycling period, analyze the enclosure atmosphere for hydrocarbon and methanol content; determine the net withdrawn methanol (in the case of diurnal emission testing with fixed volume enclosures); record temperature and barometric pressure. These are the final readings for the hydrocarbon and methanol retention check. The final hydrocarbon and methanol mass, calculated in paragraph (d) of this section, shall be within three percent of that determined in paragraph (c)(1)(viii) of this section. (For 1991-1995 calendar years, the difference may exceed ±3 percent for methanol, provided it does not exceed ±6 percent.)

(2) An enclosure to be used for the running loss test (see §86.134-96) shall meet the calibration and retention requirements of §86.117-90(c).

(3) Enclosures calibrated according to the procedures specified in either paragraph (c)(1) or (c)(2) of this section may be used for hot soak testing (see §86.138).

(d) Calculations.(1) The calculation of net methanol and hydrocarbon mass change is used to determine enclosure background and leak rate. It is also used to check the enclosure volume measurements. The methanol mass change is calculated from the initial and final methanol samples, the net withdrawn methanol (in the case of diurnal emission testing with fixed-volume enclosures), and initial and final temperature according to the following equation:

Where:

M_CH3OH = Methanol mass change, μg.

V_n = Enclosure volume, in ft ³ , as measured in paragraph (b)(1) of this section.

TE = Temperature of sample withdrawn, R.

f = Final sample.

C_MS = GC concentration of test sample.

1 = First impinger.

AV = Volume of absorbing reagent in impinger (ml).

2 = Second impinger.

V_E = Volume of sample withdrawn, ft ³ . Sample volumes must be corrected for differences in temperature to be consistent with determination of V_n, prior to being used in the equation.

T_SHED = Temperature of SHED, R.

i = Initial sample.

M_CH3OH,out = mass of methanol exiting the enclosure, in the case of fixed volume enclosures for diurnal emission testing, μg.

M_CH3OH,in = mass of methanol exiting the enclosure, in the case of fixed volume enclosures for diurnal emission testing, μg.

(2) The hydrocarbon mass change is calculated from the initial and final FID readings of hydrocarbon concentration, methanol concentration with FID response to methanol, the net withdrawn hydrocarbon and methanol (in the case of diurnal emission testing with fixed-volume enclosures), and initial and final temperature and pressure according to the following equation:

Where,

(i) M_HC = Hydrocarbon mass change, g.

(ii) C_HC = FID hydrocarbon concentration as ppm carbon, that is, ppm propane × 3, including FID response to methanol in the sample.

(iii) C_CH3OH = Methanol concentration as ppm carbon

(iv) V = Enclosure volume ft ³ (m ³), as measured in paragraph (b)(1) of this section.

(v) r = FID response factor to methanol.

(vi) P_B = Barometric pressure, in. Hg. (kPa).

(vii) T = Enclosure ambient temperature, R(K).

(viii) i = Indicates initial reading.

(ix) f = Indicates final reading.

(x)(A) k = 3.05.

(B) For SI units, k = 17.60.

(xi) M_{HC, out} = mass of hydrocarbon exiting the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, g.

(xii) M_{HC, in} = mass of hydrocarbon entering the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, g.

(3) For variable-volume enclosures, defined in §86.107(a)(1)(i), the following simplified form of the hydrocarbon mass change equation may be used:

(e) Calibration of equipment for point-source testing of running losses. For the point-source method, the running loss fuel vapor sampling system shall be calibrated as a CVS system, as specified in §86.119, with the additional specification that the vapor sampling system verification be conducted as follows:

(1) The following “gravimetric” technique can be used to verify that the vapor sampling system and analytical instruments can accurately measure a mass of gas that has been injected into the system. If the vapor sampling system will be used only in the testing of petroleum-fueled engines, the system verification may be performed using propane. If the vapor sampling system will be used with methanol-fueled vehicles as well as petroleum-fueled vehicles, the system verification performance check must include a methanol check in addition to the propane check. (Verification can also be accomplished by constant flow metering using critical flow orifice devices.)

(i) Obtain a small cylinder that has been charged with pure propane gas. Obtain another small cylinder that has been charged with pure methanol if the system will be used for methanol-fueled vehicle testing. Since this cylinder will be heated to 150-155°F, care must be taken to ensure that the liquid volume of methanol placed in the cylinder does not exceed approximately one-half of the total volume of the cylinder.

(ii) Determine a reference cylinder weight to the nearest 0.01 grams.

(iii) Operate the vapor sampling system in the normal manner and release a known quantity of pure propane into the most frequently used fuel vapor collector during the sampling period (approximately 5 minutes).

(iv) Continue to operate the vapor sampling system in the normal manner and release a known quantity of pure methanol into the system during the sampling period (approximately 5 minutes).

(v) The calculations of §86.144 are performed in the normal way, except in the case of propane. The density of propane (17.30 g/ft ³/carbon atom (0.6109 kg/m ³/carbon atom)) is used in place of the density of exhaust hydrocarbons. In the case of methanol, the density of 37.71 g/ft ³ (1.332 kg/m ³) is used.

(vi) The gravimetric mass is subtracted from the vapor sampling system measured mass and then divided by the gravimetric mass to determine the percent accuracy of the system.

(vii) The cause for any discrepancy greater than ±2 percent must be found and corrected.

(2) This procedure shall be conducted in the point-source running loss test environment with the collector installed in a vehicle in the normal test configuration. The fuel of the test vehicle shall either be diesel, or it shall be kept under 100°F (38°C). Two to six grams of pure propane and two to six grams of pure methanol shall be injected into the collector while the vehicle is operated over one Urban Dynamometer Driving Schedule (UDDS), as described in §86.115 and appendix I of this part. The propane and methanol injections shall be conducted at the ambient temperature of 95±5°F (35±3°C).

[58 FR 16030, Mar. 24, 1993, as amended at 60 FR 34343, June 30, 1995; 60 FR 43890, Aug. 23, 1995; 70 FR 72927, Dec. 8, 2005; 73 FR 38293, July 3, 2008; 79 FR 23695, Apr. 28, 2014; 88 FR 4474, Jan. 24, 2023]

§86.118-00 Dynamometer calibrations.

(a) The dynamometer shall be calibrated at least once each month or performance verified at least once each week and then calibrated as required.

(b) For large single roll electric dynamometers or equivalent dynamometer configurations, the dynamometer adjustment settings for each vehicle's emission test sequence shall be verified by comparing the force imposed during dynamometer operation with actual road load force.

[61 FR 54891, Oct. 22, 1996]

§86.119-90 CVS calibration.

The CVS is calibrated using an accurate flowmeter and restrictor valve. Measurements of various parameters are made and related to flow through the unit. Procedures used by EPA for both PDP and CFV are outlined below. Other procedures yielding equivalent results may be used if approved in advance by the Administrator. After the calibration curve has been obtained, verification of the entire system can be performed by injecting a known mass of gas into the system and comparing the mass indicated by the system to the true mass injected. An indicated error does not necessarily mean that the calibration is wrong, since other factors can influence the accuracy of the system, e.g., analyzer calibration. A verification procedure is found in paragraph (c) of this section.

(a) PDP calibrations.(1) The following calibration procedure outlines the equipment, the test configuration, and the various parameters which must be measured to establish the flow rate of the CVS pump. All the parameters related to the pump are simultaneously measured with the parameters related to a flowmeter which is connected in series with the pump. The calculated flow rate ft ³/min (at pump inlet absolute pressure and temperature) can then be plotted versus a correlation function which is the value on a specific combination of pump parameters. The linear equation which relates the pump flow and the correlation function is then determined. In the event that a CVS has a multiple speed drive, a calibration for each range used must be performed.

(2) This calibration procedure is based on the measurement of the absolute values of the pump and flowmeter parameters that relate the flow rate at each point. Three conditions must be maintained to assure the accuracy and integrity of the calibration curve. First, the pump pressures should be measured at taps on the pump rather than at the external piping on the pump inlet and outlet. Pressure taps that are mounted at the top center and bottom center of the pump drive headplate are exposed to the actual pump cavity pressures, and therefore reflect the absolute pressure differentials. Secondly, temperature stability must be maintained during the calibration. The laminar flowmeter is sensitive to inlet temperature oscillations which cause the data points to be scattered. Gradual changes (±2°F (1.1°C)) in temperature are acceptable as long as they occur over a period of several minutes. Finally, all connections between the flowmeter and the CVS pump must be absolutely void of any leakage.

(3) During an exhaust emission test the measurement of these same pump parameters enables the user to calculate the flow rate from the calibration equation.

(4) Connect a system as shown in Figure B90-8. Although particular types of equipment are shown, other configurations that yield equivalent results may be used if approved in advance by the Administrator. For the system indicated, the following data with given accuracy are required:

(5) After the system has been connected as shown in Figure B90-8, set the variable restrictor in the wide open position and run the CVS pump for 20 minutes. Record the calibration data.

(6) Reset the restrictor valve to a more restricted condition in an increment of pump inlet depression (about 4 in. H₂O (1.0 kPa) that will yield a minimum of six data points for the total calibration. Allow the system to stabilize for 3 minutes and repeat the data acquisition.

(7) Data analysis:

(i) The air flow rate, Q_s, at each test point is calculated in standard cubic feet per minute from the flowmeter data using the manufacturer's prescribed method.

(ii) The air flow rate is then converted to pump flow, V_o, in cubic feet per revolution at absolute pump inlet temperature and pressure:

V_o = (Q_s/n) × (T_p/528) × (29.92/P_p)

Where:

(A) V_o = Pump flow ft ³/rev (m ³/rev) at T_p, P_p.

(B) Q_s = Meter air flow rate in standard cubic feet per minute, standard conditions are 68°F, 29.92 in. Hg (20°C, 101.3 kPa).

(C) n = Pump speed in revolutions per minute.

(D)(1) T_p = Pump inlet temperature,°R(°K) = PTI + 460.

(2) For SI units, T_p = PTI + 273.

(E)(l) P_p = Absolute pump inlet pressure, in. Hg. (kPa) = P_B − PPI (SP.GR./13.57).

(2) For SI units, P_p = P_B − PPI.

Where:

(F) P_B = barometric pressure, in. Hg. (kPa).

(G) PPI = Pump inlet depression, in. fluid (kPa).

(H) SP.GR. = Specific gravity of manometer fluid relative to water.

(iii) The correlation function at each test point is then calculated from the calibration data:

Where:

(A) X_o = correlation function.

(B) Δ P_p = the pressure differential from pump inlet to pump outlet, in. Hg (kPa) = P_e − P_p.

(C)(1) P_e = Absolute pump outlet pressure, in Hg, (kPa) = _PB + PPO (SP.GR./13.57).

(2) For SI units, P_e = P_B + PPO.

Where:

(D) PPO = Pressure head at pump outlet, in. fluid (kPa).

(iv) A linear least squares fit is performed to generate the calibration equations which have the forms:

V_o = D_o − M(X_o)

n = A − B(Δ P_p)

D_o, M, A, and B are the slope-intercept constants describing lines.

(8) A CVS system that has multiple speeds should be calibrated on each speed used. The calibration curves generated for the ranges will be approximately parallel and the intercept values, D_o, will increase as the pump flow range decreases.

(9) If the calibration has been performed carefully, the calculated values from the equation will be within ±0.50 percent of the measured value of V_o. Values of M will vary from one pump to another, but values of D_o for pumps of the same make, model, and range should agree within ±3 percent of each other. Particulate influx from use will cause the pump slip to decrease as reflected by lower values for M. Calibrations should be performed at pump start-up and after major maintenance to assure the stability of the pump slip rate. Analysis of mass injection data will also reflect pump slip stability.

(b) CFV calibration. (1) Calibration of the CFV is based upon the flow equation for a critical venturi. Gas flow is a function of inlet pressure and temperature:

Where:

(i) Q_s = Flow.

(ii) K_v = Calibration coefficient.

(iii) P = Absolute pressure.

(iv) T = Absolute temperature.

The calibration procedure described below establishes the value of the calibration coefficient at measured values of pressure, temperature and air flow.

(2) The manufacturer's recommended procedure shall be followed for calibrating electronic portions of the CFV.

(3) Measurements necessary for flow calibration are as follows:

(4) Set up equipment as shown in Figure B90-9 and check for leaks. Any leaks between the flow measuring device and the critical flow venturi will seriously affect the accuracy of the calibration.

(5) Set the variable flow restrictor to the open position, start the blower, and allow the system to stabilize. Record data from all instruments.

(6) Vary the flow restrictor and make at least 8 readings across the critical flow range of the venturi.

(7) Data analysis: The data recorded during the calibration are to be used in the following calculations:

(i) The air flow rate, Q_s, at each test point is calculated in standard cubic feet per minute from the flow meter data using the manufacturer's prescribed method.

(ii) Calculate values of the calibration coefficient for each test point:

Where:

(A) Q_s = Flow rate in standard cubic feet per minute, standard conditions are 68°F 29.92 in. Hg (20°C, 101.3 kPa).

(B) T_v = Temperature at venturi inlet,°R(°K).

(C)(1) P_v = Pressure at venturi inlet, mm Hg (kPa) = P_B − PPI (SP.GR./13.57).

(2) For SI units, P_v = P_B − PPI.

Where:

(D) PPI = Venturi inlet pressure depression, in. fluid (kPa).

(E) SP.GR. = Specific gravity of manometer fluid, relative to water.

(iii) Plot K_v as a function of venturi inlet pressure. For sonic flow K_v will have a relatively constant value. As pressure decreases (vacuum increases), the venturi becomes unchoked and K_v decreases. See Figure B90-10.

(iv) For a minimum of 8 points in the critical region calculate an average K_v and the standard deviation.

(v) If the standard deviation exceeds 0.3 percent of the average K_v take corrective action.

(8) Calculation of a parameter for monitoring sonic flow in the CFV during exhaust emissions tests:

(i) Option 1. (A) CFV pressure ratio. Based upon the calibration data selected to meet the criteria for paragraphs (d)(7) (iv) and (v) of this section, in which K_v is constant, select the data values associated with the calibration point with the lowest absolute venturi inlet pressure. With this set of calibration data, calculated the following CFV pressure ratio limit, Pr_ratio-lim:

Where:

P_in-cal = Venturi inlet pressure (PPI in absolute pressure units), and

P_out-cal = Venturi outlet pressure (PPO in absolute pressure units), measured at the exit of the venturi diffuser outlet.

(B) The venturi pressure ratio (Pr_ratio-i) during all emissions tests must be less than, or equal to, the calibration pressure ratio limit (Pr_ratio-lim) derived from the CFV calibration data, such that:

Where:

P_in-i and P_out-i are the venturi inlet and outlet pressures, in absolute pressure units, at each i-th interval during the emissions test.

(ii) Option 2. Other methods: With prior Administrator approval, any other method may be used that assure that the venturi operates at sonic conditions during emissions tests, provided the method is based upon sound engineering principles.

(c) CVS System Verification. The following “gravimetric” technique can be used to verify that the CVS and analytical instruments can accurately measure a mass of gas that has been injected into the system. If the CVS and analytical system will be used only in the testing of petroleum-fueled engines, the system verification may be performed using either propane or carbon monoxide. If the CVS and analytical system will be used with methanol-fueled vehicles as well as petroleum-fueled vehicles, system verification performance check must include a methanol check in addition to either the propane or carbon monoxide check. (Verification can also be accomplished by constant flow metering using critical flow orifice devices.)

(1) Obtain a small cylinder that has been charged with pure propane or carbon monoxide gas (CAUTION - carbon monoxide is poisonous).

(2) Determine a reference cylinder weight to the nearest 0.01 grams.

(3) Operate the CVS in the normal manner and release a quantity of pure propane or carbon monoxide into the system during the sampling period (approximately 5 minutes).

(4) Following completion of step (3) in this paragraph (c) (if methanol injection is required), continue to operate the CVS in the normal manner and release a known quantity of pure methanol (in gaseous form) into the system during the sampling period (approximately five minutes). This step does not need to be performed with each verification, provided that it is performed at least twice annually.

(5) The calculations of §86.144 are performed in the normal way, except in the case of propane. The density of propane (17.30 g/ft ³/carbon atom (0.6109 kg/m ³/carbon atom)) is used in place of the density of exhaust hydrocarbons. In the case of carbon monoxide, the density of 32.97 g/ft ³ (1.164 kg/m ³) is used. In the case of methanol, the density of 37.71 g/ft ³ (1.332 kg/m ³) is used.

(6) The gravimetric mass is subtracted from the CVS measured mass and then divided by the gravimetric mass to determine the percent accuracy of the system.

(7) The cause for any discrepancy greater than ±2 percent must be found and corrected. (For 1991-1995 calendar years, discrepancies greater than ±2 percent are allowed for the methanol test, provided that they do not exceed ±8 percent for 1991 testing or ±6 percent for 1992-1995 testing.)

[54 FR 14518, Apr. 11, 1989, as amended at 60 FR 34344, June 30, 1995; 62 FR 47121, Sept. 5, 1997; 63 FR 24448, May 4, 1998; 65 FR 8278, Feb. 18, 2000]

§86.120-94 Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.

(a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters or flow instrumentation to determine flow through the particulate filters, methanol impingers and formaldehyde impingers. These instruments shall receive initial and periodic calibrations as follows:

(1)(i) Install a calibration device in series with the instrument. A critical flow orifice, a bellmouth nozzle, a laminar flow element or an NBS traceable flow calibration device is required as the standard device.

(ii) The flow system should be checked for leaks between the calibration and sampling meters, including any pumps that may be part of the system, using good engineering practice.

(2) Flow air through the calibration system at the sample flow rate used for particulate, methanol, and formaldehyde testing and at the backpressure which occurs during the test.

(3) When the temperature and pressure in the system have stabilized, measure the indicated gas volume over a time period of at least five minutes or until a gas volume of at least ±1 percent accuracy can be determined by the standard device. Record the stabilized air temperature and pressure upstream of the instrument and as required for the standard device.

(4) Calculate air flow at standard conditions as measured by both the standard device and the instrument(s). (Standard conditions are defined as 68°F (20°C) and 29.92 in Hg (101.3 kPa).)

(5) Repeat the procedures of paragraphs (a)(2) through (4) of this section using at least two flow rates which bracket the typical operating range.

(6) If the air flow at standard conditions measured by the instrument differs by ±1.0 percent of the maximum operating range or ±2.0 percent of the point (whichever is smaller), then a correction shall be made by either of the following two methods:

(i) Mechanically adjust the instrument so that it agrees with the calibration measurement at the specified flow rates using the criteria of paragraph (a)(6) of this section; or

(ii) Develop a continuous best fit calibration curve for the instrument (as a function of the calibration device flow measurement) from the calibration points to determine corrected flow. The points on the calibration curve relative to the calibration device measurements must be within ±1.0 percent of the maximum operating range of ±2.0 percent of the point (whichever is smaller).

(b) Other systems. A bell prover may be used to calibrate the instrument if the procedure outlined in ANSI B109.1-1973 is used. Prior approval by the Administrator is not required to use the bell prover.

[60 FR 34344, June 30, 1995]

§86.121-90 Hydrocarbon analyzer calibration.

The hydrocarbon analyzers shall receive the following initial and periodic calibration. The HFID used with petroleum-fueled diesel vehicles shall be operated at a temperature of 375°F±10°F (191°±6°C). The HFID used with methanol-fueled vehicles shall be operated at 235°±15°F (113±8°C).

(a) Initial and periodic optimization of detector response. Prior to its introduction into service and at least annually thereafter, the FID and HFID hydrocarbon analyzers shall be adjusted for optimum hydrocarbon response. Alternate methods yielding equivalent results may be used, if approved in advance by the Administrator.

(1) Follow the manufacturer's instructions or good engineering practice for instrument startup and basic operating adjustment using the appropriate FID fuel and zero-grade air.

(2) Optimize on the most common operating range. Introduce into the analyzer a propane (methane as appropriate) in air mixture (methanol in air mixture for methanol-fueled vehicles when optional methanol calibrated HFID procedure is used during the 1994 model year) with a propane (or methane or methanol as appropriate) concentration equal to approximately 90 percent of the most common operating range.

(3) One of the following is required for FID or HFID optimization:

(i) For all FIDs and HFIDs, the procedures specified by the applicable FID or HFID manufacturer.

(ii) For Beckman 400 FIDs only, implementation of the recommendations outlined in Society of Automotive Engineers (SAE) paper No. 770141, “Optimization of Flame Ionization Detector for Determination of Hydrocarbons in Diluted Automobile Exhaust”; author, Glenn D. Reschke.

(iii) For HFIDs only, the following peaking procedure. (A) With the fuel and air flow rates set in the manufacturer's recommendations, determine the analyzer response from the difference between the span-gas response and the zero gas response. Incrementally adjust the fuel flow above and below the manufacturer's specification. Record the span and zero response at these fuel flows. A plot of the difference between the span and zero response versus the fuel flow will be similar to the one shown in Fig. B87-11. Adjust the fuel-flow rate to the highest setting that produces the maximum analyzer response.

(B) To determine the optimum air flow, use the fuel flow setting determined in paragraph (a)(3)(iii)(A) of this section and vary air flow.

(iv) Alternative procedures may be used if approved in advance by the Administrator.

(4) To determine the optimum air flow, use the FID fuel flow setting determined above and vary air flow.

(5) After the optimum flow rates have been determined, record them for future reference.

(b) Initial and periodic calibration. Prior to its introduction into service and monthly thereafter the FID or HFID hydrocarbon analyzers shall be calibrated on all normally used instrument ranges, and, if testing methanol vehicles under the procedure described in §86.107-90(a)(2)(ii) or §86.110-90(a)(4), the methanol response factor shall be determined (paragraph (c) of this section). Use the same flow rate as when analyzing sample.

(1) Adjust analyzer to optimize performance.

(2) Zero the hydrocarbon analyzer with zero-grade air.

(3) Calibrate on each normally used operating range with propane in air calibration gases (either methanol or methane in air as appropriate) having nominal concentrations of 15, 30, 45, 60, 75 and 90 percent of that range. For each range calibrated, if the deviation from a least squares best-fit straight line is two percent or less of the value at each data point, concentration values may be calculated by use of a single calibration factor for that range. If the deviation exceeds two percent at any point, the best-fit non-linear equation which represents the data to within two percent of each test point shall be used to determine concentration.

(c) FID response factor to methanol. When the FID analyzer is to be used for the analysis of hydrocarbon samples containing methanol, the methanol response factor of the analyzer shall be established. The methanol response factor shall be determined at several concentrations in the range of concentrations in the exhaust sample, using either bag samples or gas bottles meeting the requirements of §86.114.

(1) The bag sample of methanol for analysis in the FID, if used, shall be prepared using the apparatus shown in Figure B90-11. A known volume of methanol is injected, using a microliter syringe, into the heated mixing zone (250°F (121°C)) of the apparatus. The methanol is vaporized and swept into the sample bag with a known volume of zero grade air measured by a gas flow meter meeting the performance requirements of §86.120.

(2) The bag sample is analyzed using the FID.

(3) The FID response factor, r, is calculated as follows:

r = FIDppm/SAMppm

Where:

(i) r = FID response factor.

(ii) FIDppm = FID reading in ppmC.

(iii) SAMppm = methanol concentration in the sample bag, or gas bottle, in ppmC. SAMppm for sample bags

Where:

(iv) 0.02406 = Volume of one mole at 29.92 in. Hg and 68°F, m ³.

(v) Fuel injected = Volume of methanol injected, ml.

(vi) Fuel density = Density of methanol, 0.7914 g/ml.

(vii) Air volume = Volume of zero grade air, m ³.

(viii) Mol. Wt. CH₃OH = 32.04.

(d) FID response factor to methane. When the FID analyzer is to be used for the analysis of gasoline, diesel, methanol, ethanol, liquefied petroleum gas, and natural gas-fueled vehicle hydrocarbon samples, the methane response factor of the analyzer must be established. To determine the total hydrocarbon FID response to methane, known methane in air concentrations traceable to the National Institute of Standards and Technology (NIST) must be analyzed by the FID. Several methane concentrations must be analyzed by the FID in the range of concentrations in the exhaust sample. The total hydrocarbon FID response to methane is calculated as follows:

r_CH4 = FIDppm/SAMppm

Where:

(1) r_CH4 = FID response factor to methane.

(2) FIDppm = FID reading in ppmC.

(3) SAMppm = the known methane concentration in ppmC.

[54 FR 14525, Apr. 11, 1989, as amended at 59 FR 48508, Sept. 21, 1994; 60 FR 34345, June 30, 1995; 70 FR 40433, July 13, 2005]

§86.122-78 Carbon monoxide analyzer calibration.

The NDIR carbon monoxide analyzer shall receive the following initial and periodic calibrations:

(a) Initial and periodic interference check. Prior to its introduction into service and annually thereafter the NDIR carbon monoxide analyzer shall be checked for response to water vapor and CO₂:

(1) Follow the manufacturer's instructions for instrument startup and operation. Adjust the analyzer to optimize performance on the most sensitive range to be used.

(2) Zero the carbon monoxide analyzer with either zero-grade air or zero-grade nitrogen.

(3) Bubble a mixture of 3 percent CO₂ in N₂ through water at room temperature and record analyzer response.

(4) An analyzer response of more than 1 percent of full scale for ranges above 300 ppm full scale or of more than 3 ppm on ranges below 300 ppm full scale will require corrective action. (Use of conditioning columns is one form of corrective action which may be taken.)

(b) Initial and periodic calibration. Prior to its introduction into service and monthly thereafter the NDIR carbon monoxide analyzer shall be calibrated.

(1) Adjust the analyzer to optimize performance.

(2) Zero the carbon monoxide analyzer with either zero-grade air or zero-grade nitrogen.

(3) Calibrate on each normally used operating range with carbon monoxide in N₂ calibration gases having nominal concentrations of 15, 30, 45, 60, 75, and 90 percent of that range. Additional calibration points may be generated. For each range calibrated, if the deviation from a least-squares best-fit straight line is 2 percent or less of the value at each data point, concentration values may be calculated by use of a single calibration factor for that range. If the deviation exceeds 2 percent at any point, the best-fit non-linear equation which represents the data to within 2 percent of each test point shall be used to determine concentration.

§86.123-78 Oxides of nitrogen analyzer calibration.

The chemiluminescent oxides of nitrogen analyzer shall receive the following initial and periodic calibration.

(a) Prior to introduction into service and at least monthly thereafter the chemiluminescent oxides of nitrogen analyzer must be checked for NO₂ to NO converter efficiency. Figure B78-9 is a reference for paragraphs (a) (1) through (11) of this section.

(1) Follow the manufacturer's instructions for instrument startup and operation. Adjust the analyzer to optimize performance.

(2) Zero the oxides of nitrogen analyzer with zero-grade air or zero-grade nitrogen.

(3) Connect the outlet of the NO_X generator to the sample inlet of the oxides of nitrogen analyzer which has been set to the most common operating range.

(4) Introduce into the NO_X generator analyzer-system an NO in nitrogen (N₂) mixture with an NO concentration equal to approximately 80 percent of the most common operating range. The NO₂ content of the gas mixture shall be less than 5 percent of the NO concentration.

(5) With the oxides of nitrogen analyzer in the NO mode, record the concentration of NO indicated by the analyzer.

(6) Turn on the NO_X generator O₂ (or air) supply and adjust the O₂ (or air) flow rate so that the NO indicated by the analyzer is about 10 percent less than indicated in step (5). Record the concentration of NO in this NO + O₂ mixture.

(7) Switch the NO_X generator to the generation mode and adjust the generation rate so that the NO measured on the analyzer is 20 percent of that measured in step (5). There must be at least 10 percent unreacted NO at this point. Record the concentration of residual NO.

(8) Switch the oxides of nitrogen analyzer to the NO_X mode and measure total NO_X. Record this value.

(9) Switch off the NO_X generation but maintain gas flow through the system. The oxides of nitrogen analyzer will indicate the NO_X in the NO + O₂ mixture. Record this value.

(10) Turn off the NO_X generator O₂ (or air) supply. The analyzer will now indicate the NO_X in the original NO in N₂ mixture. This value should be no more than 5 percent above the value indicated in step (4).

(11) Calculate the efficiency of the NO_X converted by substituting the concentrations obtained into the following equation:

Percent Efficiency = [1 + (a − b)/(c − d)] × 100

where:

a = concentration obtained in step (8).

b = concentration obtained in step (9).

c = concentration obtained in step (6).

d = concentration obtained in step (7).

If converter efficiency is not greater than 90 percent corrective action will be required.

(b) Initial and periodic calibration. Prior to its introduction into service and monthly thereafter the chemiluminescent oxides of nitrogen analyzer shall be calibrated on all normally used instrument ranges. Use the same flow rate as when analyzing samples. Proceed as follows:

(1) Adjust analyzer to optimize performance.

(2) Zero the oxides of nitrogen analyzer with zero-grade air or zero-grade nitrogen.

(3) Calibrate on each normally used operating range with NO in N2 calibration gases having nominal concentrations of 15, 30, 45, 60, 75, and 90 percent of that range. For each range calibrated, if the deviation from a least-squares best-fit straight line is 2 percent or less of the value at each data point, concentration values may be calculated by use of a single calibration factor for that range. If the deviation exceeds 2 percent at any point, the best-fit non-linear equation which represents the data to within 2 percent of each test point shall be used to determine concentration.

(c) When testing methanol-fueled vehicles, it may be necessary to clean the analyzer frequently to prevent interference with NO_X measurements (see EPA/600/S3-88/040).

[42 FR 32954, June 28, 1977, as amended at 42 FR 45652, Sept. 12, 1977; 52 FR 47869, Dec. 16, 1987; 58 FR 58422, Nov. 1, 1993; 60 FR 34347, June 30, 1995]

§86.124-78 Carbon dioxide analyzer calibration.

Prior to its introduction into service and monthly thereafter the NDIR carbon dioxide analyzer shall be calibrated:

(a) Follow the manufacturer's instructions for instrument startup and operation. Adjust the analyzer to optimize performance.

(b) Zero the carbon dioxide analyzer with either zero-grade air or zero-grade nitrogen.

(c) Calibrate on each normally used operating range with carbon dioxide in N₂ calibration gases with nominal concentrations of 15, 30, 45, 60, 75, and 90 percent of that range. Additional calibration points may be generated. For each range calibrated, if the deviation from a least-squares best-fit straight line is 2 percent or less of the value at each data point, concentration values may be calculated by use of a single calibration factor for that range. If the deviation exceeds 2 percent at any point, the best-fit non-linear equation which represents the data to within 2 percent of each test point shall be used to determine concentration.

§86.125-94 Methane analyzer calibration.

Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated:

(a) Follow the manufacturer's instructions for instrument startup and operation. Adjust the analyzer to optimize performance.

(b) Zero the methane analyzer with zero-grade air.

(c) Calibrate on each normally used operating range with CH₄ in air with nominal concentrations of 15, 30, 45, 60, 75, and 90 percent of that range. Additional calibration points may be generated. For each range calibrated, if the deviation from a least-squares best-fit straight line is 2 percent or less of the value at each data point, concentration values may be calculated by use of a single calibration factor for that range. If the deviation exceeds 2 percent at any point, the best-fit non-linear equation which represents the data to within 2 percent of each test point shall be used to determine concentration.

[56 FR 25774, June 5, 1991]

§86.126-90 Calibration of other equipment.

Other test equipment used for testing shall be calibrated as often as required by the manufacturer or as necessary according to good practice. Specific equipment requiring calibration are the gas chromatograph and flame ionization detector used in measuring methanol and the high pressure liquid chromatograph (HPLC) and ultraviolet detector for measuring formaldehyde.

[54 FR 14527, Apr. 11, 1989]

§86.127-00 Test procedures; overview.

Applicability. The procedures described in this and subsequent sections are used to determine the conformity of vehicles with the standards set forth in subpart A or S of this part (as applicable) for light-duty vehicles and light-duty trucks. Except where noted, the procedures of paragraphs (a) through (b) of this section, §86.127-96 (c) and (d), and the contents of §§86.135-94, 86.136-90, 86.137-96, 86.140-94, 86.142-90, and 86.144-94 are applicable for determining emission results for vehicle exhaust emission systems designed to comply with the FTP emission standards, or the FTP emission element required for determining compliance with composite SFTP standards. Paragraphs (f) and (g) of this section discuss the additional test elements of aggressive driving (US06) and air conditioning (SC03) that comprise the exhaust emission components of the SFTP. Section §86.127-96(e) discusses fuel spitback emissions and paragraphs (h) and (i) of this section are applicable to all vehicle emission test procedures. Section 86.127-00 includes text that specifies requirements that differ from §86.127-96. Where a paragraph in §86.127-96 is identical and applicable to §86.127-00, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.127-96.”

(a) The overall test consists of prescribed sequences of fueling, parking, and operating test conditions. Vehicles are tested for any or all of the following emissions:

(1) Gaseous exhaust THC, CO, NO_X. CO₂ (for petroleum-fueled and gaseous- fueled vehicles), plus CH₃OH and HCHO for methanol-fueled vehicles, plus CH₄ (for vehicles subject to the NMHC and NMHCE standards).

(2) Particulates.

(3) Evaporative HC (for gasoline-fueled, methanol-fueled and gaseous-fueled vehicles) and CH₃OH (for methanol-fueled vehicles). The evaporative testing portion of the procedure occurs after the exhaust emission test; however, exhaust emissions need not be sampled to complete a test for evaporative emissions.

(4) Fuel spitback (this test is not required for gaseous-fueled vehicles).

(b) The FTP Otto-cycle exhaust emission test is designed to determine gaseous THC, CO, CO₂, CH₄, NO_X, and particulate mass emissions from gasoline-fueled, methanol-fueled and gaseous-fueled Otto-cycle vehicles as well as methanol and formaldehyde from methanol-fueled Otto-cycle vehicles, while simulating an average trip in an urban area of 11 miles (18 kilometers). The test consists of engine start-ups and vehicle operation on a chassis dynamometer through a specified driving schedule (see paragraph (a), EPA Urban Dynamometer Driving Schedule, of appendix I to this part). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(c)-(e) [Reserved]. For guidance see §86.127-96.

(f) The element of the SFTP for exhaust emissions related to aggressive driving (US06) is designed to determine gaseous THC, NMHC, CO, CO₂, CH₄, and NO_X emissions from gasoline-fueled or diesel-fueled vehicles (see §86.158-00 Supplemental test procedures; overview, and §86.159-00 Exhaust emission test procedures for US06 emissions). The test cycle simulates urban driving speeds and accelerations that are not represented by the FTP Urban Dynamometer Driving Schedule simulated trips discussed in paragraph (b) of this section. The test consists of vehicle operation on a chassis dynamometer through a specified driving cycle (see paragraph (g), US06 Dynamometer Driving Schedule, of appendix I to this part). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(g)(1) The element of the SFTP related to the increased exhaust emissions caused by air conditioning operation (SC03) is designed to determine gaseous THC, NMHC, CO, CO₂, CH₄, and NO_X emissions from gasoline-fueled or diesel fueled vehicles related to air conditioning use (see §86.158-00 Supplemental federal test procedures; overview and §86.160-00 Exhaust emission test procedure for SC03 emissions). The test cycle simulates urban driving behavior with the air conditioner operating. The test consists of engine startups and vehicle operation on a chassis dynamometer through specified driving cycles (see paragraph (h), SC03 Dynamometer Driving Schedule, of appendix I to this part). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler. The testing sequence includes an approved preconditioning cycle, a 10 minute soak with the engine turned off, and the SC03 cycle with measured exhaust emissions.

(2) The SC03 air conditioning test is conducted with the air conditioner operating at specified settings and the ambient test conditions of:

(i) Air temperature of 95°F;

(ii) 100 grains of water/pound of dry air (approximately 40 percent relative humidity);

(iii) Simulated solar heat intensity of 850 W/m ² (see §86.161-00(d)); and

(iv) air flow directed at the vehicle that will provide representative air conditioner system condenser cooling at all vehicle speeds (see §86.161-00(e)).

(3) Manufacturers have the option of simulating air conditioning operation during testing at other ambient test conditions provided they can demonstrate that the vehicle tail pipe exhaust emissions are representative of the emissions that would result from the SC03 cycle test procedure and the ambient conditions of paragraph (g)(2) of this section. The Administrator has approved two optional air conditioning test simulation procedures AC1 and AC2 (see §86.162-00) for only the model years of 2000 through 2002. If a manufacturer desires to conduct simulation SC03 testing for model year 2003 and beyond, the simulation test procedure must be approved in advance by the Administrator (see §§86.162-00 and 86.163-00).

(h) Except in cases of component malfunction or failure, all emission control systems installed on or incorporated in a new motor vehicle shall be functioning during all procedures in this subpart. Maintenance to correct component malfunction or failure shall be authorized in accordance with §86.098-25 or §86.1834-01 as applicable.

(i) Background concentrations are measured for all species for which emissions measurements are made. For exhaust testing, this requires sampling and analysis of the dilution air. For evaporative testing, this requires measuring initial concentrations. (When testing methanol-fueled vehicles, manufacturers may choose not to measure background concentrations of methanol and/or formaldehyde, and then assume that the concentrations are zero during calculations.)

[61 FR 54891, Oct. 22, 1996, as amended at 64 FR 23921, May 4, 1999]

§86.127-12 Test procedures; overview.

Applicability. The procedures described in this subpart are used to determine the conformity of vehicles with the standards set forth in subpart A or S of this part (as applicable) for light-duty vehicles, light-duty trucks, and medium-duty passenger vehicles. Except where noted, the procedures of paragraphs (a) through (d) of this section, and the contents of §§86.135-00, 86.136-90, 86.137-96, 86.140-94, 86.142-90, and 86.144-94 are applicable for determining emission results for vehicle exhaust emission systems designed to comply with the FTP emission standards, or the FTP emission element required for determining compliance with composite SFTP standards. Paragraph (e) of this section discusses fuel spitback emissions. Paragraphs (f) and (g) of this section discuss the additional test elements of aggressive driving (US06) and air conditioning (SC03) that comprise the exhaust emission components of the SFTP. Paragraphs (h) and (i) of this section are applicable to all vehicle emission test procedures.

(a) The overall test consists of prescribed sequences of fueling, parking, and operating test conditions. Vehicles are tested for any or all of the following emissions, depending upon the specific test requirements and the vehicle fuel type:

(1) Gaseous exhaust THC, NMHC, NMOG, CO, NO_X, CO₂, N₂O, CH₄, CH₃OH, C₂H₅OH, C₂H₄O, and HCHO.

(2) Particulates.

(3) Evaporative HC (for gasoline-fueled, methanol-fueled and gaseous-fueled vehicles) and CH₃OH (for methanol-fueled vehicles). The evaporative testing portion of the procedure occurs after the exhaust emission test; however, exhaust emissions need not be sampled to complete a test for evaporative emissions.

(4) Fuel spitback (this test is not required for gaseous-fueled vehicles).

(b) The FTP Otto-cycle exhaust emission test is designed to determine gaseous THC, NMHC, NMOG, CO, CO₂, CH₄, NO_X, N₂O, and particulate mass emissions from gasoline-fueled, methanol-fueled and gaseous-fueled Otto-cycle vehicles as well as methanol and formaldehyde from methanol-fueled Otto-cycle vehicles, as well as methanol, ethanol, acetaldehyde, and formaldehyde from ethanol-fueled vehicles, while simulating an average trip in an urban area of approximately 11 miles (approximately 18 kilometers). The test consists of engine start-ups and vehicle operation on a chassis dynamometer through a specified driving schedule (see paragraph (a) of appendix I to this part for the Urban Dynamometer Driving Schedule). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(c) The diesel-cycle exhaust emission test is designed to determine particulate and gaseous mass emissions during the test described in paragraph (b) of this section. For petroleum-fueled diesel-cycle vehicles, diluted exhaust is continuously analyzed for THC using a heated sample line and analyzer; the other gaseous emissions (CH₄, CO, CO₂, N₂O, and NO_X) are collected continuously for analysis as in paragraph (b) of this section. For methanol- and ethanol-fueled vehicles, THC, methanol, formaldehyde, CO, CO₂, CH₄, N₂O, and NO_X are collected continuously for analysis as in paragraph (b) of this section. Additionally, for ethanol-fueled vehicles, ethanol and acetaldehyde are collected continuously for analysis as in paragraph (b) of this section. THC, methanol, ethanol, acetaldehyde, and formaldehyde are collected using heated sample lines, and a heated FID is used for THC analyses. Simultaneous with the gaseous exhaust collection and analysis, particulates from a proportional part of the diluted exhaust are collected continuously on a filter. The mass of particulate is determined by the procedure described in §86.139. This testing requires a dilution tunnel as well as the constant volume sampler.

(d) The evaporative emission test (gasoline-fueled vehicles, methanol-fueled and gaseous-fueled vehicles) is designed to determine hydrocarbon and methanol evaporative emissions as a consequence of diurnal temperature fluctuation, urban driving and hot soaks following drives. It is associated with a series of events that a vehicle may experience and that may result in hydrocarbon and/or methanol vapor losses. The test procedure is designed to measure:

(1) Diurnal emissions resulting from daily temperature changes (as well as relatively constant resting losses), measured by the enclosure technique (see §86.133-96);

(2) Running losses resulting from a simulated trip performed on a chassis dynamometer, measured by the enclosure or point-source technique (see §86.134-96; this test is not required for gaseous-fueled vehicles); and

(3) Hot soak emissions, which result when the vehicle is parked and the hot engine is turned off, measured by the enclosure technique (see §86.138-96).

(e) Fuel spitback emissions occur when a vehicle's fuel fill neck cannot accommodate dispensing rates. The vehicle test for spitback consists of a short drive followed immediately by a complete refueling event. This test is not required for gaseous-fueled vehicles.

(f) The element of the SFTP for exhaust emissions related to aggressive driving (US06) is designed to determine gaseous THC, NMHC, CO, CO₂, CH₄, and NO_X emissions from gasoline-fueled or diesel-fueled vehicles (see §86.158-08 Supplemental test procedures; overview, and §86.159-08 Exhaust emission test procedures for US06 emissions). The test cycle simulates urban driving speeds and accelerations that are not represented by the FTP Urban Dynamometer Driving Schedule simulated trips discussed in paragraph (b) of this section. The test consists of vehicle operation on a chassis dynamometer through a specified driving cycle (see paragraph (g), US06 Dynamometer Driving Schedule, of appendix I to this part). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(g)(1) The element of the SFTP related to the increased exhaust emissions caused by air conditioning operation (SC03) is designed to determine gaseous THC, NMHC, CO, CO₂, CH₄, and NO_X emissions from gasoline-fueled or diesel fueled vehicles related to air conditioning use (see §86.158-08 Supplemental Federal test procedures; overview and §86.160-00 Exhaust emission test procedure for SC03 emissions). The test cycle simulates urban driving behavior with the air conditioner operating. The test consists of engine startups and vehicle operation on a chassis dynamometer through specified driving cycles (see paragraph (h), SC03 Dynamometer Driving Schedule, of appendix I to this part). A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler. The testing sequence includes an approved preconditioning cycle, a 10 minute soak with the engine turned off, and the SC03 cycle with measured exhaust emissions.

(2) The SC03 air conditioning test is conducted with the air conditioner operating at specified settings and the ambient test conditions of:

(i) Air temperature of 95°F;

(ii) 100 grains of water/pound of dry air (approximately 40 percent relative humidity);

(iii) Simulated solar heat intensity of 850 W/m ² (see §86.161-00(d)); and

(iv) Air flow directed at the vehicle that will provide representative air conditioner system condenser cooling at all vehicle speeds (see §86.161-00(e)).

(3) Manufacturers have the option of simulating air conditioning operation during testing at other ambient test conditions provided they can demonstrate that the vehicle tail pipe exhaust emissions are representative of the emissions that would result from the SC03 cycle test procedure and the ambient conditions of paragraph (g)(2) of this section. The simulation test procedure must be approved in advance by the Administrator (see §§86.162-03 and 86.163-00).

(h) Except in cases of component malfunction or failure, all emission control systems installed on or incorporated in a new motor vehicle shall be functioning during all procedures in this subpart. Maintenance to correct component malfunction or failure shall be authorized in accordance with §86.007-25 or §86.1834-01 as applicable.

(i) Background concentrations are measured for all species for which emissions measurements are made. For exhaust testing, this requires sampling and analysis of the dilution air. For evaporative testing, this requires measuring initial concentrations. (When testing methanol-fueled vehicles, manufacturers may choose not to measure background concentrations of methanol and/or formaldehyde, and then assume that the concentrations are zero during calculations.)

[75 FR 25678, May 7, 2010]

§86.128-79 Transmissions.

(a) All test conditions, except as noted, shall be run according to the manufacturer's recommendations to the ultimate purchaser, Provided, That: Such recommendations are representative of what may reasonably be expected to be followed by the ultimate purchaser under in-use conditions.

(b) Vehicles equipped with free wheeling or overdrive, except as noted, shall be tested with these features operated according to the manufacturer's recommendations to the ultimate purchaser.

(c) Idle modes less than one minute in length shall be run with automatic transmissions in “Drive” and the wheels braked; manual transmissions shall be in gear with the clutch disengaged, except for the first idle mode (see §§86.134, 86.136, and 86.137). The first idle mode and idle modes longer than one minute in length may be run with automatic transmissions in “Neutral;” manual transmissions may be in “Neutral” with the clutch engaged (clutch may be disengaged for engine start-up). If an automatic transmission is in “Neutral” during an idle mode, it shall be placed in “Drive” with the wheels braked at least 5 seconds before the end of the idle mode. If a manual transmission is in “Neutral” during an idle mode, it shall be placed in gear with the clutch disengaged at least 5 seconds before the end of the idle mode.

(d) The vehicle shall be driven with appropriate accelerator pedal movement necessary to achieve the speed versus time relationship prescribed by the driving schedule. Both smoothing of speed variations and excessive accelerator pedal perturbations are to be avoided.

(e) Accelerations shall be driven smoothly following representative shift speeds and procedures. For manual transmissions, the operator shall release the accelerator pedal during each shift and accomplish the shift with minimum time. If the vehicle cannot accelerate at the specified rate, the vehicle shall be operated at maximum available power until the vehicle speed reaches the value prescribed for that time in the driving schedule.

(f) The deceleration modes shall be run in gear using brakes or accelerator pedal as necessary to maintain the desired speed. Manual transmission vehicles shall have the clutch engaged and shall not change gears from the previous mode. For those modes which decelerate to zero, manual transmission clutches shall be depressed when the speed drops below 15 mph (24.1 km/h), when engine roughness is evident, or when engine stalling is imminent.

(g)(1) In the case of test vehicles equipped with manual transmissions, the transmission shall be shifted in accordance with procedures which are representative of shift patterns that may reasonably be expected to be followed by vehicles in use, in terms of such variables as vehicle speed or percent rated engine speed. At the Administrator's discretion, a test vehicle may also be shifted according to the shift procedures recommended by the manufacturer to the ultimate purchaser, if such procedures differ from those which are reasonably expected to be followed by vehicles in use.

(2) A manufacturer may recommend to the ultimate purchaser shift procedures other than those used in testing by the EPA, Provided that: All shift procedures (including multiple shift speeds) which the manufacturer proposes to supply to the ultimate purchaser are provided to the Administrator as part of the manufacturer's application for certification, or as an amendment to such application, under §86.079-32, §86.079-33, §86.082-34, or §86.1844-01 as applicable.

(h) Downshifting is allowed at the beginning of or during a power mode in accordance with the shift procedure determined in paragraph (g)(1) of this section.

[43 FR 52921, Nov. 14, 1978, as amended at 58 FR 16033, Mar. 24, 1993; 64 FR 23921, May 4, 1999; 79 FR 23696, Apr. 28, 2014]

§86.129-00 Road load power, test weight, and inertia weight class determination.

Applicability. Section 86.129-94 (a) applies to all vehicle testing. Section 86.129-80 (b) and (c) are applicable to vehicles from engine families which are not required to meet SFTP requirements, although a manufacturer may elect to use the requirements in paragraphs (e) and (f) of this section instead of 86.129-80 (b) and (c) on any vehicle. Section §86.129-94(d) which discusses fuel temperature profile, is applicable to evaporative emission running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine families required to comply with SFTP requirements. Section 86.129-00 includes text that specifies requirements that differ from §86.129-80 or §86.129-94. Where a paragraph in §86.129-80 or §86.129-94 is identical and applicable to §86.129-00, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.129-80.” or “[Reserved]. For guidance see §86.129-94.”

(a) [Reserved]. For guidance see §86.129-94.

(b)-(c) [Reserved]. For guidance see §86.129-80.

(d) [Reserved]. For guidance see §86.129-94.

(e)(1) For each test vehicle from an engine family required to comply with SFTP requirements, the manufacturer shall supply representative road load forces for the vehicle at speeds between 15 km/hr (9.3 mph) and 115 km/hr (71.5 mph). The road load force shall represent vehicle operation on a smooth level road, during calm winds, with no precipitation, at an ambient temperature of 20°C (68°F), and atmospheric pressure of 98.21 kPa. Road load force for low speed may be extrapolated. Manufacturers may, at their option, use road load forces meeting the objectives of paragraph (f) of this section for any vehicle.

(2) The dynamometer's power absorption shall be set for each vehicle's emission test sequence such that the force imposed during dynamometer operation matches actual road load force at all speeds.

(3) The 10 percent adjustment in road load power for air conditioning discussed in §86.129-80(b)(3), is not applicable when road load forces are determined for dynamometer testing using paragraphs (e)(1) and (e)(2) of this section.

(f)(1) Required test dynamometer inertia weight class selections for the test elements of FTP, US06, and SC03 are determined by the test vehicles test weight basis and corresponding equivalent weight as listed in the tabular information of §86.129-94(a). With the exception of the fuel economy test weight information in footnote 4 to the table in §86.129-94(a), none of the other footnotes to the tabular listing apply to emission tests utilizing an approved single roll dynamometer or equivalent dynamometer configuration. All light-duty vehicles and light light-duty trucks are to be tested at the inertia weight class corresponding to their equivalent test weight.

(i) For light-duty vehicles and light light-duty trucks, test weight basis is loaded vehicle weight, which is the vehicle weight plus 300 pounds.

(ii) For heavy light-duty trucks, the definition of test weight basis varies depending on the SFTP test element being tested.

(A) For the aggressive driving cycle (US06), the test weight basis is the vehicle curb weight plus 300 pounds.

(B) For the FTP and the air conditioning (SC03) element of the SFTP, the test weight is the average of the curb weight plus GVWR.

(C) Regardless of other requirements in this section relating to the testing of HLDTs, for Tier 2 and Tier 3 HLDTs, the test weight basis for FTP and SFTP testing (both US06 and SC03), if applicable, is the vehicle curb weight plus 300 pounds. For MDPVs certified to standards in bin 11 in Tables S04-1 and 2 in§86.1811-04, the test weight basis must be adjusted loaded vehicle weight (ALVW) as defined in this part.

(2) Dynamic inertia load adjustments may be made to the test inertia weight during specific US06 acceleration events when wide open throttle operation is equal to or greater than eight (8) seconds (see §86.108-00). The dynamic inertia weight adjustment procedure must be approved in advance of conducting official US06 testing. The Administrator will perform confirmatory US06 testing using the same dynamometer inertia adjustment procedures as the manufacturer if:

(i) The manufacturer submits a request to the Administrator; and

(ii) The manufacturer provides the dynamometer hardware and/or software necessary for these adjustments to the Administrator.

Editorial Note: At 64 FR 23921, May 4, 1999, §86.129-00 was amended by revising footnote 4 to the table in paragraph (a) and by revising paragraph (d)(1)(iv). Since both paragraphs (a) and (d) of §86.129-00 were reserved and contained no text, these amendments could not be made.

[61 FR 54892, Oct. 22, 1996, as amended at 65 FR 6850, Feb. 10, 2000; 86 FR 34366, Jun. 29, 2021]

§86.129-80 Road load power, test weight, and inertia weight class determination.

(a) [Reserved]

(b) Power absorption unit adjustment - light-duty trucks.(1) The power absorption unit shall be adjusted to reproduce road load power at 50 mph true speed. The indicated road load power setting shall take into account the dynamometer friction. The relationship between road load (absorbed) power and indicated road load power for a particular dynamometer shall be determined by the procedure outlined in §86.118 or other suitable means.

(2) The road load power listed in the table above shall be used or the vehicle manufacturer may determine the road load power by an alternate procedure requested by the manufacturer and approved in advance by the Administrator.

(3) Where it is expected that more than 33 percent of a car line within an engine-system combination will be equipped with air conditioning per §86.080-24(g)(2), the road load power listed above or as determined in paragraph (b)(2) of this section shall be increased by 10 percent, up to a maximum increase of 1.4 horsepower, for testing all test vehicies representing that car line within that engine-system combination if those vehicles are intended to be offered with air conditioning in production. The above increase for air conditioning shall be added prior to rounding off as instructed by notes 2 and 3 of the table.

(c) Power absorption unit adjustment - light-duty vehicles.(1) The power absorption unit shall be adjusted to reproduce road load power at 50 mph true speed. The dynamometer power absorption shall take into account the dynamometer friction, as discussed in §86.118.

(2) The dynamometer road load setting is determined from the equivalent test weight, the reference frontal area, the body shape, the vehicle protuberances, and the tire type by the following equations.

(i) For light-duty vehicles to be tested on a twin roll dynamometer.

Hp = aA + P + tW

where:

Hp = the dynamometer power absorber setting at 50 mph (horsepower).

A = the vehicle reference frontal area (ft ²). The vehicle reference frontal area is defined as the area of the orthogonal projection of the vehicle; including tires and suspension components, but excluding vehicle protuberances, onto a plane perpendicular to both the longitudinal plane of the vehicle and the surface upon which the vehicle is positioned. Measurements of this area shall be computed to the nearest tenth of a square foot using a method approved in advance by the Administrator.

P = the protuberance power correction factor from table 1 of this paragraph (horsepower).

W = vehicle equivalent test weight (lbs) from the table in paragraph (a).

a = 0.43 for fastback-shaped vehicles; = 0.50 for all other light duty vehicles.

t = 0.0 for vehicles equipped with radial ply tires; = 3 × 10^{− 4} for all other vehicles.

A vehicle is considered to have a fastback shape if the rearward projection of that portion of the rear surface (A_b) which slopes at an angle of less than 20 degrees from the horizontal is at least 25 percent as large as the vehicle reference frontal area. In addition, this surface must be smooth, continuous, and free from any local transitions greater than four degrees. An example of a fastback shape is presented in Figure 1.

The protuberance frontal area, A_p, is defined in a manner analogous to the definition of the vehicle reference frontal area, i.e., the total area of the orthogonal projections of the vehicle mirrors, hood ornaments, roof racks, and other protuberance onto a plane(s) perpendicular to both the longitudinal plane of the vehicle and the surface upon which the vehicle is positioned. A protuberance is defined as any fixture attached to the vehicle protruding more than 1 inch from the vehicle surface and having a projected area greater than 0.01 ft ² with the area calculated by a method approved in advance by the Administrator. Included in the total protuberance frontal area shall be all fixtures which occur as standard equipment. The area of any optional equipment shall also be included if it is expected that more than 33 percent of the car line sold will be equipped with this option.

(ii) The dynamometer power absorber setting for light-duty vehicles shall be rounded to the nearest 0.1 horsepower.

(iii) For light-duty vehicles to be tested on a single, large roll dynamometer.

Hp = aA + P + (5.0 × 10 ⁻⁴ + 0.33t)W

All symbols in the above equation are defined in paragraph (c)(2)(i) of this section. The rounding criteria of paragraph (c)(2)(i) also apply to this paragraph.

(3) The road load power calculated above shall be used or the vehicle manufacturer may determine the road load power by an alternate procedure requested by the manufacturer and approved in advance by the Administrator.

(4) Where it is expected that more than 33 percent of a car line within an engine-system combination will be equipped with air conditioning, per §86.080-24(g)(2), the road load power as determined in paragraph (c) (2) or (3) of this section shall be increased by 10 percent up to a maximum increment of 1.4 horsepower, for testing all test vehicles of that car line within that engine-system combination if those vehicles are intended to be offered with air conditioning in production. This power increment shall be added to the indicated dynamometer power absorption setting prior to rounding off this value.

[42 FR 45653, Sept. 12, 1977, as amended at 43 FR 52921, Nov. 14, 1978; 79 FR 23696, Apr. 28, 2014]

§86.129-94 Road load power, test weight, inertia weight class determination, and fuel temperature profile.

Section 86.129-94 includes text that specifies requirements that differ from §86.129-80. Where a paragraph in §86.129-80 is identical and applicable to §86.129-94, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.129-80.” Where a corresponding paragraph of §86.129-80 is not applicable, this is indicated by the statement “[Reserved].”

(a) Flywheels, electrical, or other means of simulating test weight as shown in the following table shall be used. If the equivalent test weight specified is not available on the dynamometer being used, the next higher equivalent test weight (not to exceed 250 pounds) available shall be used:

(b)-(c) [Reserved]. For guidance see §86.129-80.

(d) Fuel temperature profile- (1) General requirements.(i) To be tested for running losses, as specified in §86.134, a vehicle must have a fuel temperature profile. The following procedure is used to generate the fuel temperature profile, which serves as a target for controlling fuel temperatures during the running loss test. This profile represents the fuel temperature change that occurs during on-road driving. If a vehicle has more than one fuel tank, a profile shall be established for each tank. Manufacturers may also simultaneously generate a profile for vapor temperatures.

(ii) If a manufacturer uses a vehicle model to develop a profile to represent multiple models, the vehicle model selected must have the greatest expected fuel temperature increase during driving of all those models it represents. Also, manufacturers must select test vehicles with any available vehicle options that increase fuel temperatures during driving (for example, any feature that limits underbody airflow).

(iii) Manufacturers may conduct testing to develop fuel temperature profiles in a laboratory setting, subject to approval by the Administrator. The laboratory facility should simulate outdoor testing to reproduce fuel and vapor temperature behavior over the specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind velocities around and underneath the test vehicle. Indoor testing to develop the fuel temperature profiles must be conducted with little or no vehicle-specific adjustment of laboratory parameters. Manufacturers would need to maintain an ongoing demonstration of correlation between laboratory and outdoor measurement of fuel temperatures. Specifically, fuel temperatures and pressures from indoor driving should be at least as high as measured when driving outdoors according to the procedures described in this section.

(iv) Small-volume manufacturers, as defined in §86.094-14(b)(1), may use an alternate method for generating fuel temperature profiles, subject to the approval of the Administrator.

(v) The Administrator may conduct testing to establish any vehicle's temperature profiles or to verify compliance with fuel tank pressure requirements.

(2) Vehicle instrumentation. (i) The vehicle must be equipped with temperature sensors and pressure transducers, as described in §86.107-96 (e) and (f), and a driver's aid, which shall be configured to provide the test driver with the desired vehicle speed vs. time trace and the actual vehicle speed.

(ii) A computer, data logger, or strip chart data recorder shall record the following parameters at a minimum during the test run:

(A) Desired speed;

(B) Actual speed;

(C) Instantaneous average liquid fuel temperature (T_liq); and

(D) Vapor space pressure (the Administrator may omit measurement of fuel tank pressure).

(iii) The data recording system described in paragraph (d)(2)(ii) of this section shall be capable of resolving time to ±1 s, capable of resolving temperature to ±2°F, capable of resolving pressure to ±1.0 inch of water, and capable of resolving speed to ±1 mph. The temperature and pressure signals shall be recorded at intervals of up to 1 minute; speed signals shall be recorded at intervals of up to 1 second.

(3) Ambient conditions. The procedure shall be run under the following ambient conditions. Conditions should be representative of sunny summer days.

(i) Starting ambient temperature (T_{amb, o}) shall be at least 95°F, steady or increasing (no more than 2°F drop) during the procedure. Ambient temperature shall be measured and recorded in regular intervals of at least once every 5 minutes. Measure ambient temperature with the following requirements (based on Federal Standard for Siting Meteorological Sensors at Airports, FCM-S4-1987). The sensors shall be mounted 5 ±1 feet (1.5 ±0.3 meters) above ground level. The sensors shall be protected from radiation from the sun, sky, earth, and any other surrounding objects, but at the same time be adequately ventilated. The sensors shall be installed in such a position as to ensure that measurements are representative of the free air circulation in the locality and not influenced by artificial conditions such as large buildings, cooling towers, and expanses of concrete and tarmac. Keep any grass and vegetation within 100 feet (30 meters) of the sensor clipped to a height of about 10 inches (25 centimeters) or less.

(ii) Wind conditions shall be calm to light with maximum wind speed of 15 mph. In the case of temporary gusting, wind speeds between 15 and 25 mph may occur for up to 5 percent of the total driving time without invalidating the data collection. Wind speed shall be measured and recorded in regular intervals of at least once per minute. Measure wind speed with the following requirements (based on Federal Standard for Siting Meteorological Sensors at Airports, FCM-S4-1987). The site should be relatively level, but small gradual slopes are acceptable. The sensor shall be mounted 30 to 33 feet (9 to 10 meters) above the average ground height within a radius of 500 feet (150 meters). The sensor height shall not exceed 33 feet, except as necessary to be at least 15 feet (5 meters) above the height of any obstruction (e.g. vegetation, buildings, etc.) within a 500 foot (150 meter) radius. An object is considered to be an obstruction if the included lateral angle from the sensor to the ends of the object is 10 degrees or more.

(iii) Road surface temperature shall be at least 125°F throughout the driving period. Pavement temperature shall be measured and recorded in regular intervals of at least once per minute. The track temperature may be measured with an embedded sensor, a portable temperature probe, or an infrared pyrometer that can provide an accuracy of ±2°F. Temperatures must be measured on a surface representative of the surface where the vehicle is driven.

(iv) Conditions shall be sunny or mostly sunny with a maximum cloud cover of 25 percent.

(v) Reported cloud cover, wind speed, and ambient temperature should be consistent with that reported by the nearest weather station; the Administrator may request justification of any discrepancy.

(4) Profile determination procedure.(i) Drain the fuel tank(s) and fill with test fuel to the “tank fuel volume” defined in §86.082-2. The test fuel should meet the specifications of §86.113, except that fuel with a lower volatility may be used, subject to Administrator approval. Manufacturers using a lower volatility fuel must generate a vapor temperature profile for demonstrating compliance with the limit on fuel tank pressure during the running loss test (see §86.134-96).

(ii) The vehicle shall be moved to the location where the data is to be collected. It may be driven a maximum distance of 5 miles and may also be transported by other means. The vehicle shall be stabilized by one of the following methods:

(A) The vehicle shall be parked for a minimum of 12 hours in an open area on a surface that is representative of the test road, without any artificial heating or cooling of the fuel. The orientation of the front of the vehicle during parking (e.g., N, SW, etc.) shall be documented.

(B) The vehicle may be soaked in a temperature-controlled environment to stabilize fuel temperatures. Before starting the drive, the vehicle shall be stabilized with fuel temperatures 95 ±3°F for at least one hour. The fuel temperature may not exceed 98°F at any time before the beginning of the driving schedule, during which only whole-vehicle heating and cooling may be used to control fuel temperatures. If a manufacturer uses the provisions of paragraph (d)(7)(v) of this section to establish a lower initial fuel temperature for the running loss test, the fuel in the test vehicle may not be stabilized at a temperature higher than the newly established initial fuel temperature.

(iii) Once the ambient conditions specified in paragraph (d)(3) of this section are met and the vehicle has been stabilized according to paragraph (d)(4)(ii) of this section, the vehicle's engine may be started. The vehicle's air conditioning system (if so equipped) shall be set to the “normal” air conditioning mode and adjusted to the minimum discharge air temperature and high fan speed. Vehicles equipped with automatic temperature controlled air conditioning systems shall be set to operate in “automatic” temperature and fan modes with the system set at 72°F.

(iv) The vehicle may be operated at minimum throttle for a period up to 60 seconds prior to the start of the driving schedule, as necessary to move from the parking location onto the road surface. The driver's aid shall be started and the vehicle operated over the driving cycle specified in §86.134-96(b) with the transmission operated in the same manner as specified in §86.128-79. The data recording system shall provide a record of the required parameters over the entire period of driving.

(5) Records required. In addition to the vehicle data recording, the following parameters shall be documented for the determination of the fuel temperature profile:

(i) Date and time of vehicle fueling;

(ii) Odometer reading at vehicle fueling;

(iii) Date and time vehicle was parked, parking location and orientation;

(iv) Odometer reading at parking;

(v) Date and time engine was started;

(vi) Time of initiation of first UDDS;

(vii) Time of completion of the driving cycle;

(viii) Ambient temperatures throughout the period of driving (T_amb);

(ix) Wind speed throughout the period of driving;

(x) Track surface temperatures throughout the period of driving cycle (T_sur);

(xi) Percent cloud cover during the period of driving; and

(xii) Ambient temperature, wind speed, and percent cloud cover reported by the nearest weather station for the time corresponding most closely to the period of driving.

(6) Fuel tank pressure. Tank pressure shall not exceed 10 inches of water at any time during the temperature profile determination unless a pressurized system is used and the manufacturer demonstrates that vapor would not be vented to the atmosphere upon fuel cap removal.

(7) Calculation of temperature profiles.(i) The traces from the driving schedule shall be verified to meet the speed tolerance requirements of §86.115. The following conditions shall be verified:

(A) T_{amb, i}≥T_{amb, o}−2°F.

Where,

(1)i = instantaneous measurement throughout the drive; and

(2)o = initial measurement at the start of the specified driving schedule.

(B) T_{amb, o}≥95°F.

(C) T_{sur, i}−T_{amb, i}≥30°F.

(D) W_max≤15 mph.

(ii) Failure to comply with any of these requirements shall result in invalidation of the data and require that the procedure be repeated, beginning with the fuel drain at paragraph (d)(4)(i) of this section.

(iii) If all these requirements are met, the following calculations shall be performed to determine a profile for liquid fuel temperatures and, if applicable, for vapor temperatures:

T_{i, profile} = T_i-T_o.

Where:

(A) Ti,_profile = the series of temperatures that comprise the relative temperature profile.

(B) T_i = the series of observed liquid fuel or vapor temperatures during the drive.

(C) T_o = the liquid fuel or vapor temperature observed at the start of the specified driving schedule.

(iv) The relative temperature profile consists of the set of temperatures at each 1-minute interval. If temperatures are sampled more frequently than once per minute, the temperature data points may represent a rolling average of temperatures sampled for up to one-minute intervals. If multiple valid test runs are conducted for any model, then all the collected data shall be used to calculate a composite profile, based on the average temperatures at each point. The absolute temperature profile is determined by adding 95°F (35°C) to each point of the relative profile. Other methodologies for developing corrected liquid fuel and vapor space temperature profiles may be used if demonstrated to yield equivalent results and approved in advance by the Administrator.

(v) Manufacturers may use a lower initial fuel temperature for the running loss test, if approved in advance by the Administrator. To demonstrate the need for such an adjustment, manufacturers would be expected to determine the maximum fuel temperature experienced by a vehicle during an extended park or after driving one UDDS cycle when exposed to the ambient conditions described in paragraph (d)(3) of this section. To use this provision, manufacturers would have to show maximum fuel temperatures no greater than 92°F.

[56 FR 25775, June 5, 1991, as amended at 58 FR 16033, Mar. 24, 1993; 59 FR 39649, Aug. 3, 1994; 60 FR 43891, Aug. 23, 1995; 65 FR 59956, Oct. 6, 2000]

§86.130-96 Test sequence; general requirements.

Paragraphs (a) through (d) of this section are applicable to vehicles tested for the FTP test. Paragraph (e) of this section is applicable to vehicles tested for the SFTP supplemental tests of air conditioning (SC03) and aggressive driving (US06). Paragraph (f) of this section is applicable to all emission testing.

(a)(1) Gasoline- and methanol-fueled vehicles. The test sequence shown in Figure 1 of 40 CFR 1066.801 shows the steps encountered as the test vehicle undergoes the procedures subsequently described to determine conformity with the standards set forth. The full three- diurnal sequence depicted in Figure 1 of 40 CFR 1066.801 tests vehicles for all sources of evaporative emissions. The supplemental two-diurnal test sequence is designed to verify that vehicles sufficiently purge their evaporative canisters during the exhaust emission test. Sections 86.132-96, 86.133-96, and 86.138-96 describe the separate specifications of the supplemental two-diurnal test sequence.

(2) Gaseous-fueled vehicles. The test sequence shown in Figure 1 of 40 CFR 1066.801 shows the steps encountered as the test vehicle undergoes the procedures subsequently described to determine conformity with the standards set forth, with the exception that the fuel drain and fill and precondition canister steps are not required for gaseous-fueled vehicles. In addition, the supplemental two-diurnal test and the running loss test are not required.

(b) The vehicle test for fuel spitback during fuel dispensing is conducted as a stand-alone test (see §86.146). This test is not required for gaseous-fueled vehicles.

(c) Ambient temperature levels encountered by the test vehicle shall be not less than 68°F nor more than 86°F, unless otherwise specified. If a different ambient temperature is specified for soaking the vehicle, the soak period may be interrupted once for up to 10 minutes to transport the vehicle from one soak area to another, provided the ambient temperature experienced by the vehicle is never below 68°F. The temperatures monitored during testing must be representative of those experienced by the test vehicle.

(d) The vehicle shall be approximately level during all phases of the test sequence to prevent abnormal fuel distribution.

(e) The supplemental tests for exhaust emissions related to aggressive driving (US06) and air conditioning (SC03) use are conducted as stand-alone tests as described in §§86.158 through 86.160. These tests may be performed in any sequence that maintains the appropriate preconditioning requirements as specified in §86.132.

(f) If tests are invalidated after collection of emission data from previous test segments, the test may be repeated to collect only those data points needed to complete emission measurements. Compliance with emission standards may be determined by combining emission measurements from different test runs. If any emission measurements are repeated, the new measurements supersede previous values.

[58 FR 16034, Mar. 24, 1993, as amended at 59 FR 48509, Sept. 21, 1994; 60 FR 43893, Aug. 23, 1995; 79 FR 23696, Apr. 28, 2014; 86 FR 34366, June. 29, 2021]

§86.131-96 Vehicle preparation.

(a) For gasoline- and methanol-fueled vehicles prepare the fuel tank(s) for recording the temperature of the prescribed test fuel, as described in §86.107-96(e).

(b) Provide additional fittings and adapters, as required, to accommodate a fuel drain at the lowest point possible in the tank(s) as installed on the vehicle.

(c) For preconditioning that involves loading the evaporative emission canister(s) with butane, provide valving or other means as necessary to allow purging and loading of the canister(s).

(d) For vehicles to be tested for running loss emissions, prepare the fuel tank(s) for measuring and recording the temperature and pressure of the fuel tank as specified in §86.107-96 (e) and (f). Measurement of vapor temperature is optional during the running loss test. If vapor temperature is not measured, fuel tank pressure need not be measured.

(e) For vehicles to be tested for running loss emissions, prepare the exhaust system by sealing or plugging all detectable sources of exhaust gas leaks. The exhaust system shall be tested or inspected to ensure that detectable exhaust hydrocarbons are not emitted into the running loss enclosure during the running loss test.

(f) For vehicles to be tested for aggressive driving emissions (US06), provide a throttle position sensing signal that is compatible with the test dynamometer. This signal provides the input information that controls dynamometer dynamic inertia weight adjustments (see §§86.108-00(b)(2)(ii) and 86.129-00(f)(2)). If a manufacturer chooses not to implement dynamic inertia adjustments for a portion or all of their product line, this requirement is not applicable.

(g) You may disable any AECDs that have been approved solely for emergency vehicle applications under paragraph (4) of the definition of defeat device in §86.1803. The emission standards do not apply when any of these AECDs are active.

[58 FR 16037, Mar. 24, 1993, as amended at 60 FR 43895, Aug. 23, 1995; 79 FR 23696, Apr. 28, 2014]

§86.132-00 Vehicle preconditioning.

Applicability. Section 86.132-96 (a) through (c)(1) and (d) through (m) and paragraph (c)(2) of this section are applicable to FTP and evaporative emission testing. Paragraphs (n) and (o) of this section are applicable to vehicles tested for the SFTP supplemental tests of aggressive driving (US06) and air conditioning (SC03). Section 86.132-00 includes text that specifies requirements that differ from §86.132-96. Where a paragraph in §86.132-96 is identical and applicable to §86.132-00, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.132-96.”

(a)-(c)(1) [Reserved]. For guidance see §86.132-96.

(c)(2)(i) Once a test vehicle has completed the refueling and vehicle soak steps specified in §86.132-96(b) and (c)(1), these steps may be omitted in subsequent testing with the same vehicle and the same fuel specifications, provided the vehicle remains under laboratory ambient temperature conditions for at least 6 hours before starting the next test. In such cases, each subsequent test shall begin with the preconditioning drive specified in §86.132-96(c)(1). The test vehicle may not be used to set dynamometer horsepower.

(ii) The SFTP test elements of aggressive driving (US06) and air conditioning (SC03) can be run immediately or up to 72 hours after the official FTP and/or evaporative test sequence without refueling provided the vehicle has remained under laboratory ambient temperature conditions. If the time interval exceeds 72 hours or the vehicle leaves the ambient temperature conditions of the laboratory, the manufacturer must repeat the refueling operation.

(d)-(m) [Reserved]. For guidance see §86.132-96.

(n) Aggressive Driving Test (US06) Preconditioning. (1) If the US06 test follows the exhaust emission FTP or evaporative testing, the refueling step may be deleted and the vehicle may be preconditioned using the fuel remaining in the tank (see paragraph (c)(2)(ii) of this section). The test vehicle may be pushed or driven onto the test dynamometer. Acceptable cycles for preconditioning are as follows:

(i) Preconditioning may consist of a 505, 866, highway, US06 or SC03 test cycles.

(ii) [Reserved]

(iii) If a manufacturer has concerns about fuel effects on adaptive memory systems, a manufacturer may precondition a test vehicle on test fuel and the US06 cycle. Upon request from a manufacturer, the administrator will also perform the preconditioning with the US06 cycle.

(iv) The preconditioning cycles for the US06 test schedule are conducted at the same ambient test conditions as the certification US06 test.

(2) Following the preconditioning specified in paragraphs (n)(1)(i), (ii), and (iii) of this section, the test vehicle is returned to idle for one to two minutes before the start of the official US06 test cycle.

(o) Air Conditioning Test (SC03) Preconditioning. (1) If the SC03 test follows the exhaust emission FTP or evaporative testing, the refueling step may be deleted and the vehicle may be preconditioned using the fuel remaining in the tank (see paragraph (c)(2)(ii) of this section). The test vehicle may be pushed or driven onto the test dynamometer. Acceptable cycles for preconditioning are as follows:

(i) If the soak period since the last exhaust test element is less than or equal to two hours, preconditioning may consist of a 505, 866, or SC03 test cycles.

(ii) If the soak period since the last exhaust test element is greater than two hours, preconditioning consists of one full Urban Dynamometer Driving Cycle. Manufacturers, at their option, may elect to use the preconditioning in paragraph (o)(1)(i) of this section when the soak period exceeds two hours.

(2) Following the preconditioning specified in paragraphs (o)(1)(i) and (ii) of this section, the test vehicle is turned off, the vehicle cooling fan(s) is turned off, and the vehicle is allowed to soak for 10 minutes prior to the start of the official SC03 test cycle.

(3) The preconditioning cycles for the SC03 air conditioning test and the 10 minute soak are conducted at the same ambient test conditions as the SC03 certification air conditioning test.

[61 FR 54893, Oct. 22, 1996, as amended at 74 FR 61547, Nov. 25, 2009]

§86.132-96 Vehicle preconditioning.

(a) Prepare the vehicle for testing as described in this section. Store the vehicle before testing in a way that prevents fuel contamination and preserves the integrity of the fuel system. The vehicle shall be moved into the test area and the following operations performed.

(b)(1) Gasoline- and Methanol-Fueled Vehicles. Drain the fuel tank(s) and fill with test fuel, as specified in §86.113, to the “tank fuel volume” defined in §86.082-2. Install the fuel cap(s) within one minute after refueling.

(2) Gaseous-Fueled Vehicles. Fill fuel tanks with fuel that meets the specifications in §86.113. Fill the fuel tanks to a minimum of 75 percent of service pressure for natural gas-fueled vehicles or a minimum of 75 percent of available fill volume for liquefied petroleum gas-fueled vehicles. However, if you omit the refueling event in paragraph (f) of this section, refuel the vehicles to 85 percent instead of 75 percent. Draining the fuel tanks at the start of the test is not required if the fuel in the tanks already meets the specifications in §86.113.

(c)(1) Gasoline- and methanol-fueled vehicles shall be soaked for at least 6 hours after being refueled. Petroleum-fueled diesel vehicles and gaseous-fueled vehicles shall be soaked for at least 1 hour after being refueled. Following this soak period, the test vehicle shall be placed, either by being driven or pushed, on a dynamometer and operated through one Urban Dynamometer Driving Schedule (UDDS), specified in §86.115 and appendix I of this part.

(2) Once a test vehicle has completed the refueling and vehicle soak steps specified in paragraphs (b) and (c)(1) of this section, these steps may be omitted in subsequent testing with the same vehicle and the same fuel specifications, provided the vehicle remains under laboratory ambient temperature conditions for at least 6 hours before starting the next test. In such cases, each subsequent test shall begin with the preconditioning drive specified in this paragraph. The test vehicle may not be used to set dynamometer horsepower.

(d) For unusual circumstances where the need for additional preconditioning is demonstrated by the manufacturer, such preconditioning may be allowed with the advance approval of the Administrator.

(e) The Administrator may also choose to conduct or require to be conducted additional preconditioning to ensure that the evaporative emission control system is stabilized in the case of gasoline-fueled and methanol-fueled vehicles, or to ensure that the exhaust system is stabilized in the case of petroleum- and methanol-fueled diesel vehicles. The preconditioning shall consist of one of the following:

(1) For gasoline- and methanol-fueled vehicles. (i) Additional preconditioning shall consist of no more than 50 miles of mileage accumulation under typical driving conditions, either on the road or on a dynamometer.

(ii) In the case of repeat testing on a flexible-fueled vehicle, in which the test fuel is changed, the following preconditioning procedure shall be used. This additional preconditioning allows the vehicle to adapt to the new fuel before the next test run.

(A) Purge the vehicle's evaporative canister for 60 minutes at 0.8 cfm.

(B) Drain the fuel tank(s) and fill with 3 gallons of the test fuel.

(C) Start the vehicle and allow it to idle for 1 minute.

(D) Drain the fuel tank(s) and fill with the new test fuel to the “tank fuel volume” defined in §86.082-2. The average temperature of the dispensed fuel shall be less than 60°F.

(E) Conduct a heat build according to the procedure specified in §86.133-90.

(F) The vehicle shall be placed, either by being driven or pushed, on a dynamometer and operated through one UDDS, specified in §86.115 and appendix I of this part.

(G) Following the dynamometer drive, the vehicle shall be turned off for 5 minutes, then restarted and allowed to idle for 1 minute. The vehicle shall then be turned off for 1 minute, and allowed to idle again for 1 minute.

(H) After the vehicle is turned off the last time, it may be tested for evaporative and exhaust emissions, starting with paragraph (a) of this section.

(2) For petroleum-fueled diesel, methanol-fueled diesel, and gaseous-fueled vehicles. The preconditioning shall consist of either of the following:

(i) An initial one hour minimum soak and, one, two, or three driving cycles of the UDDS, as described in paragraph (c) of this section, each followed by a soak of at least one hour with engine off, engine compartment cover closed and cooling fan off. The vehicle may be driven off the dynamometer following each UDDS for the soak period; or

(ii) For abnormally treated vehicles, as defined in §86.085-2 or §86.1803-01 as applicable, two Highway Fuel Economy Driving Schedules, found in 40 CFR part 600, appendix I, run in immediate succession, with the road load power set at twice the value obtained from §86.129-80.

(f) Drain and then fill the vehicle's fuel tank(s) with test fuel, as specified in §86.113, to the “tank fuel volume” defined in §86.082-2. Refuel the vehicle within 1 hour after completing the preconditioning drive. Install fuel cap(s) within 1 minute after refueling. Park the vehicle within five minutes after refueling. However, for the following vehicles you may omit this refueling event and instead drive the vehicle off the dynamometer and park it within five minutes after the preconditioning drive:

(1) Diesel-fueled vehicles.

(2) Gaseous-fueled vehicles.

(3) Fuel economy data vehicles.

(4) In-use vehicles subject to testing under §86.1845.

(g) The vehicle shall be soaked for not less than 12 hours nor more than 36 hours before the cold start exhaust emission test. The soak period starts at the end of the refueling event, or at the end of the previous drive if there is no refueling.

(h) During the soak period for the three-diurnal test sequence described in §86.130-96, precondition any evaporative canisters as described in this paragraph (h); however, canister preconditioning is not required for fuel economy data vehicles. For vehicles with multiple canisters in a series configuration, the set of canisters must be preconditioned as a unit. For vehicles with multiple canisters in a parallel configuration, each canister must be preconditioned separately. If production evaporative canisters are equipped with a functional service port designed for vapor load or purge steps, the service port shall be used during testing to precondition the canister. In addition, for model year 1998 and later vehicles equipped with refueling canisters, these canisters shall be preconditioned for the three-diurnal test sequence according to the procedure in paragraph (j)(1) of this section. If a vehicle is designed to actively control evaporative or refueling emissions without a canister, the manufacturer shall devise an appropriate preconditioning procedure, subject to the approval of the Administrator.

(1)(i) Prepare the evaporative emission canister for the canister purging and loading operation. The canister shall not be removed from the vehicle, unless access to the canister in its normal location is so restricted that purging and loading can only reasonably be accomplished by removing the canister from the vehicle. Special care shall be taken during this step to avoid damage to the components and the integrity of the fuel system. A replacement canister may be temporarily installed during the soak period while the canister from the test vehicle is preconditioned.

(ii) The canister purge shall be performed with ambient air of humidity controlled to 50±25 grains per pound of dry air. This may be accomplished by purging the canister in a room that is conditioned to this level of absolute humidity. The flow rate of the purge air shall be maintained at a nominal flow rate of 0.8 cfm and the duration shall be determined to provide a total purge volume flow through the canister equivalent to 300 canister bed volume exchanges. The bed volume is based on the volume of adsorbing material in the canister.

(iii) The evaporative emission canister shall then be loaded by sending to the canister an amount of commercial grade butane vapors equivalent to 1.5 times its nominal working capacity. The canister shall be loaded with a mixture composed of 50 percent butane and 50 percent nitrogen by volume at a rate of 15±2 grams butane per hour. If the canister loading at that rate takes longer than 12 hours, a manufacturer may determine a new rate, based on completing the canister loading in no less than 12 hours. The new rate may be used for all subsequent canister loading according to paragraph (h) of this section. The time of initiation and completion of the canister loading shall be recorded.

(iv) The determination of a canister's nominal working capacity shall be based on the average capacity of no less than five canisters that are in a stabilized condition.

(A) For stabilization, each canister must be loaded no less than 10 times and no more than 100 times to 2-gram breakthrough with a 50/50 mixture by volume of butane and nitrogen, at a rate of 15 grams butane per hour. Each canister loading step must be preceded by canister purging with 300 canister bed volume exchanges at 0.8 cfm.

(B) For determining working capacity, each canister must first be purged with 300 canister bed volume exchanges at 0.8 cfm. The working capacity of each canister shall be established by determining the mass of butane required to load the canister from the purged state so that it emits 2 grams of hydrocarbon vapor; the canister must be loaded with a 50/50 mixture by volume of butane and nitrogen, at a rate of 15 grams butane per hour.

(2) For methanol-fueled and flexible-fueled vehicles, canister preconditioning shall be performed with a fuel vapor composition representative of that which the vehicle would generate with the fuel mixture used for the current test. Manufacturers shall develop a procedure to precondition the evaporative canister, if the vehicle is so equipped, for the different fuel. The procedure shall represent a canister loading equivalent to that specified in paragraph (h)(1) of this section and shall be approved in advance by the Administrator.

(i) [Reserved]

(j) During the soak period for the supplemental two-diurnal test sequence described in §86.130-96, precondition any evaporative canisters using one of the methods described in this paragraph (j); however, canister preconditioning is not required for fuel economy data vehicles. For vehicles with multiple canisters in a series configuration, the set of canisters must be preconditioned as a unit. For vehicles with multiple canisters in a parallel configuration, each canister must be preconditioned separately. In addition, for model year 1998 and later vehicles equipped with refueling canisters, these canisters shall be preconditioned for the supplemental two-diurnal test sequence according to the procedure in paragraph (j)(1) of this section. Canister emissions are measured to determine breakthrough. Breakthrough is here defined as the point at which the cumulative quantity of hydrocarbons emitted is equal to 2 grams.

(1) Butane loading to breakthrough. The following procedure provides for emission measurement in an enclosure. Breakthrough may also be determined by measuring the weight gain of an auxiliary evaporative canister connected downstream of the vehicle's canister, in which case, the following references to the enclosure can be ignored. The auxiliary canister shall be well purged prior to loading. If production evaporative canisters are equipped with a functional service port designed for vapor load or purge steps, the service port shall be used during testing to precondition the canister.

(i) Prepare the evaporative/refueling emission canister for the canister loading operation. The canister shall not be removed from the vehicle, unless access to the canister in its normal location is so restricted that purging and loading can only reasonably be accomplished by removing the canister from the vehicle. Special care shall be taken during this step to avoid damage to the components and the integrity of the fuel system. A replacement canister may be temporarily installed during the soak period while the canister from the test vehicle is preconditioned.

(ii) The evaporative emission enclosure shall be purged for several minutes. Warning: If at any time the concentration of hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 ppm C the enclosure should be immediately purged. This concentration provides at least a 4:1 safety factor against the lean flammability limit.

(iii) The FID hydrocarbon analyzer shall be zeroed and spanned immediately prior to the canister loading procedure.

(iv) If not already on, the evaporative enclosure mixing fan shall be turned on at this time.

(v) Place the vehicle in a sealed enclosure and measure emissions with a FID.

(vi)(A) For gasoline-fueled vehicles, load the canister with a mixture composed of 50 percent butane and 50 percent nitrogen by volume at a rate of 40 grams butane per hour.

(B) For methanol-fueled and flexible-fueled vehicles, canister preconditioning shall be performed with a fuel vapor composition representative of that which the vehicle would generate with the fuel mixture used for the current test. Manufacturers shall develop a procedure to precondition the evaporative canister, if the vehicle is so equipped, for the different fuel.

(vii) As soon as the canister reaches breakthrough, the vapor source shall be shut off.

(viii) Reconnect the evaporative/refueling emission canister and restore the vehicle to its normal operating condition.

(2) Load with repeated diurnal heat builds to breakthrough. The following procedure provides for emission measurement in an enclosure. Breakthrough may also be determined by measuring the weight gain of an auxiliary evaporative canister connected downstream of the vehicle's canister, in which case, the following references to the enclosure can be ignored. The auxiliary canister shall be well purged with dry air prior to loading.

(i) The evaporative emission enclosure shall be purged for several minutes. Warning: If at any time the concentration of hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 ppm C the enclosure should be immediately purged. This concentration provides at least a 4:1 safety factor against the lean flammability limit.

(ii) The FID hydrocarbon analyzer shall be zeroed and spanned immediately prior to the diurnal heat builds.

(iii) If not already on, the evaporative enclosure mixing fan shall be turned on at this time.

(iv) The fuel tank(s) of the prepared vehicle shall be drained and filled with test fuel, as specified in §86.113, to the “tank fuel volume” defined in §86.082-2. The average temperature of the dispensed fuel shall be 60±12°F (16±7°C). The fuel tank cap(s) shall be installed within 1 minute after refueling.

(v) Within one hour of being refueled, the vehicle shall be placed, with the engine shut off, in the evaporative emission enclosure. The fuel tank temperature sensor shall be connected to the temperature recording system. A heat source, specified in §86.107-90(a)(4), shall be properly positioned with respect to the fuel tank(s) and connected to the temperature controller.

(vi) The temperature recording system shall be started.

(vii) The fuel may be artificially heated to the starting diurnal temperature.

(viii) When the fuel temperature reaches at least 69°F (21°C), immediately: turn off purge blower (if not already off); close and seal enclosure doors; and initiate measurement of the hydrocarbon level in the enclosure.

(ix) When the fuel temperature reaches 72±2°F (22±1°C), start the diurnal heat build.

(x) The fuel shall be heated in such a way that its temperature change conforms to the following function to within ±4°F (±3°C):

F = T_o + 0.4t; or

for SI units,

C = T_o + (2/9)t.

Where,

F = fuel temperature,°F;

C = fuel temperature,°C;

t = time since beginning of test, minutes; and

T_o = initial temperature in°F (°C for SI units).

(xi) As soon as breakthrough occurs or when the fuel temperature reaches 96°F (36°C), whichever occurs first, the heat source shall be turned off, the enclosure doors shall be unsealed and opened, and the vehicle fuel tank cap(s) shall be removed. If breakthrough has not occurred by the time the fuel temperature reaches 96°F (36°C), the heat source shall be removed from the vehicle, the vehicle shall be removed (with engine still off) from the evaporative emission enclosure and the entire procedure outlined in paragraph (j)(2) of this section shall be repeated until breakthrough occurs.

(xii) After breakthrough occurs, the fuel tank(s) of the prepared vehicle shall be drained and filled with test fuel, as specified in §86.113, to the “tank fuel volume” defined in §86.082-2. The fuel shall be stabilized to a temperature within 3°F of the lab ambient before beginning the driving cycle for the exhaust emission test.

(k) [Reserved]

(l) Vehicles to be tested for exhaust emissions only shall be processed according to §§86.135 through 86.137. Vehicles to be tested for evaporative emissions shall be processed in accordance with the procedures in §§86.133 through 86.138, starting with §86.135.

(m) Vehicles to be tested for evaporative emissions with the supplemental two-diurnal test sequence described in §86.130-96, shall proceed according to §§86.135 through 86.137, followed by the supplemental hot soak test (see §86.138-96(k)) and the supplemental diurnal emission test (see §86.133-96(p)).

(n) With prior approval of the Administrator, manufacturers may use an alternative canister loading method in lieu of the applicable canister loading method described in the provisions of paragraphs (h), (j)(1) and (j)(2) of this section, provided the alternative method is shown to be equivalent or result in a more fully loaded canister (a canister that has adsorbed an equal or greater amount of hydrocarbon vapors) than the applicable canister loading method required by the provisions of paragraphs (h), (j)(1) and (j)(2) of this section. Additionally, the Administrator may conduct confirmatory certification testing and in-use testing using the alternative canister loading method used by the manufacturer to test applicable certification and/or in-use vehicles or the appropriate method outlined in the provisions of paragraphs (h), (j)(1) and (j)(2) of this section.

[58 FR 16037, Mar. 24, 1993, as amended at 59 FR 16296, Apr. 6, 1994; 59 FR 48509, Sept. 21, 1994; 60 FR 43895, Aug. 23, 1995; 64 FR 23922, May 4, 1999; 70 FR 72927, Dec. 8, 2005; 79 FR 23696, Apr. 28, 2014; 89 FR 28156, Apr. 18, 2024]

§86.133-96 Diurnal emission test.

(a)(1) The diurnal emission test for gasoline-, methanol- and gaseous-fueled vehicles consists of three 24-hour test cycles following the hot soak test. Emissions are measured for each 24-hour cycle, with the highest emission level used to determine compliance with the standards specified in subpart A of this part. The Administrator may truncate a test after any 24-hour cycle without affecting the validity of the collected data. Sampling of emissions from the running loss and hot soak tests is not required as preparation for the diurnal emission test. The diurnal emission test may be conducted as part of either the three- diurnal test sequence or the supplemental two-diurnal test sequence, as described in §86.130-96.

(2) For the full three-diurnal test sequence, the diurnal emission test outlined in paragraphs (b) through (o) of this section follows the high-temperature hot soak test concluded in §86.138-96(j).

(3) For the supplemental two-diurnal test sequence, the diurnal emission test outlined in paragraph (p) of this section follows the alternate hot soak test specified in §86.138-96(k). This test is not required for gaseous-fueled vehicles.

(b) The test vehicle shall be soaked for not less than 6 hours nor more than 36 hours between the end of the hot soak test and the start of the diurnal emission test. For at least the last 6 hours of this period, the vehicle shall be soaked at 72°±3°F. The temperature tolerance may be waived for up to 10 minutes to allow purging of the enclosure or transporting the vehicle into the enclosure at the beginning of the diurnal emission test.

(c) The test vehicle shall be exposed to ambient temperatures cycled according to the profile specified in §86.133 and appendix II of this part.

(1) Temperatures measured with the underbody temperature sensor shall follow the profile with a maximum deviation of 3°F at any time and an average temperature deviation not to exceed 2°F, where the average deviation is calculated using the absolute value of each measured deviation. In addition, the temperature from the sidewall temperature sensors shall follow the profile with a maximum deviation of 5°F at any time.

(2) Ambient temperatures shall be measured at least every minute. Temperature cycling shall begin when time = 0 minutes, as specified in paragraph (i)(5) of this section.

(d) The diurnal enclosure shall be purged for several minutes prior to the test. Warning: If at any time the concentration of hydrocarbons, of methanol or of methanol and hydrocarbons exceeds 15,000 ppm C the enclosure should be immediately purged. This concentration provides at least a 4:1 safety factor against the lean flammability limit.

(e) The test vehicle, with the engine shut off and the test vehicle windows and luggage compartment(s) opened, shall be moved into the diurnal enclosure.

(f)-(g) [Reserved]

(h) Prior to sampling for emissions and throughout the period of cycled ambient temperatures, the mixing fan(s) shall circulate the air at a rate of 0.8±0.2 cfm per cubic foot of ambient volume. The mixing fan(s), plus any additional fans if needed, shall also maintain a minimum wind speed of 5 mph (8 km/hr) under the fuel tank of the test vehicle. The Administrator may adjust fan speed and location to ensure sufficient air circulation around the fuel tank. The wind speed requirement may be satisfied by consistently using a fan configuration that has been demonstrated to maintain a broad 5-mph air flow in the vicinity of the vehicle's fuel tank, subject to verification by the Administrator.

(i) Emission sampling may begin as follows:

(1) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned immediately prior to the sampling.

(2) Impingers charged with known volumes of pure deionized water shall be placed in the methanol sampling system (methanol-fueled vehicles only).

(3) Turn off purge blowers (if not already off).

(4) Close and seal enclosure doors (if not already closed and sealed).

(5) Within 10 minutes of closing and sealing the doors, analyze enclosure atmosphere for hydrocarbons and record. This is the initial (time = 0 minutes) hydrocarbon concentration, C_HCi, required in §86.143. Hydrocarbon emissions may be sampled continuously during the test period.

(6) Analyze the enclosure atmosphere for methanol, if applicable, and record. The methanol sampling must start simultaneously with the initiation of the hydrocarbon analysis and continue for 4.0±0.5 minutes. This is the initial methanol concentration, C_CH3_OHi, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses. If the test is conducted in a fixed-volume enclosure that allows airflow into and out of the enclosure, the effect of makeup air dilution must be factored into the analysis.

(j) If testing indicates that a vehicle design may result in fuel temperature responses during enclosure testing that are not representative of in-use summertime conditions, the Administrator may adjust air circulation and temperature during the test as needed to ensure that the test sufficiently duplicates the vehicle's in-use experience.

(k) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned immediately prior to the end of each emission sampling period.

(l) Fresh impingers shall be installed in the methanol collection system immediately prior to the end of each emission measurement, if applicable.

(m) The end of the first, second, and third emission sampling period shall occur 1440±6, 2880±6, 4320±6 minutes, respectively, after the beginning of the initial sampling, as specified in paragraph (i)(5) of this section.

(1) At the end of each emission sampling period, analyze the enclosure atmosphere for hydrocarbons and record. This is the final hydrocarbon concentration, C_HCf, required in §86.143. The emission measurement at the end of each period becomes the initial hydrocarbon concentration, C_HCi, of the next emission sampling period.

(2) Analyze the enclosure atmosphere for methanol, if applicable, and record. The methanol sampling must start simultaneously with the initiation of the hydrocarbon analysis and continue for 4.0±0.5 minutes. This is the final (time = 1440 minutes) methanol concentration, C_CH3_OHf, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses. If the test is conducted in a fixed-volume enclosure that allows airflow into and out of the enclosure, the effect of makeup air dilution must be factored into the analysis.

(n) At the end of the temperature cycling period the enclosure doors shall be unsealed and opened, the test vehicle windows and luggage compartments may be closed and the test vehicle, with the engine shut off, shall be removed from the enclosure.

(o) This completes the full three-diurnal evaporative emission test sequence described in §86.130-96.

(p) For the supplemental two-diurnal test sequence described in §86.130-96, the following steps shall be performed in lieu of the steps described in paragraphs (b) through (n) of this section.

(1) For the supplemental two-diurnal test sequence, the test vehicle shall be soaked for not less than 6 hours nor more than 36 hours between the end of the hot soak test described in §86.138-96(k), and the start of the two-diurnal emission test. For at least the last 6 hours of this period, the vehicle shall be soaked at 72±3°F.

(2) The vehicle shall be tested for diurnal emissions according to the procedures specified in paragraphs (c) through (n) of this section, except that the test includes only two 24-hour periods. Therefore the end of the first and second emission sampling periods shall occur 1440±6 and 2880±6 minutes, respectively, after the initial sampling.

(3) This completes the supplemental two-diurnal test sequence for evaporative emission measurement.

[58 FR 16039, Mar. 24, 1993, as amended at 59 FR 48509, Sept. 21, 1994; 60 FR 43896, Aug. 23, 1995]

§86.134-96 Running loss test.

(a) Overview. Gasoline- and methanol-fueled vehicles are to be tested for running loss emissions during simulated high-temperature urban driving; this test is not required for gaseous-fueled vehicles. During operation, tank temperatures are controlled according to a prescribed profile to simulate in-use conditions. If the vehicle is determined to have exceeded the standard before the end of the running loss test, the test may be terminated without invalidating the data. The test can be run either in a sealed enclosure or with the point-source method, as specified in paragraph (g) of this section. Measurement of vapor temperature is optional during the running loss test; however, if testing by the Administrator shows that a vehicle has exceeded an emission standard without measurement of vapor temperatures, the manufacturer may, utilizing its own resources, conduct subsequent testing on that vehicle to determine if the exceedance is attributable to inadequate control of vapor temperatures.

(b) Driving schedule. Conduct the running loss test by operating the test vehicle through one Urban Dynamometer Driving Schedule (UDDS), a 2-minute idle, two New York City Cycles, another 2-minute idle, another UDDS, then another 2-minute idle (see §86.115 and appendix I of this part). Fifteen seconds after the engine starts, place the transmission in gear. Twenty seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule. The transmission shall be operated according to the specifications of §86.128 during the driving cycles.

(c) Dynamometer operation. (1) The exhaust from the vehicle must be routed outside the test cell or enclosure. Exhaust gases may, but need not, be collected and sampled.

(2) Provisions of §86.135-90(c) shall apply.

(3) Practice runs over the prescribed driving schedule may not be performed at test point.

(4) Provisions of §86.135-90 (e) and (f) shall apply.

(5) If the dynamometer horsepower must be adjusted manually, it shall be set within 1 hour prior to the running loss test phase. The test vehicle shall not be used to make this adjustment. Dynamometers using automatic control of preselectable power settings may be set any time prior to the beginning of the emissions test.

(6) Dynamometer roll or shaft revolutions shall be used to determine the actual driving distance for the running loss test, D_RL, required in §86.143. The revolutions shall be measured on the same roll or shaft used for measuring the vehicle's speed.

(7) Provisions of §86.135-90(i) shall apply.

(8) The test run may be stopped if a warning light or gauge indicates that the vehicle's engine coolant has overheated.

(d) Engine starting and restarting. (1) Provisions of §86.136-90(a) shall apply.

(2) If the vehicle does not start after the manufacturer's recommended cranking time (or 10 continuous seconds in the absence of a manufacturer's recommendation), cranking shall cease for the period recommended by the manufacturer (or 10 seconds in the absence of a manufacturer's recommendation). This may be repeated for up to three start attempts. If the vehicle does not start after three attempts, the reason for failure to start shall be determined. If failure to start is an operational error, the vehicle shall be rescheduled for testing, starting with the soak period immediately preceding the running loss test.

(3) If failure to start is caused by a vehicle malfunction, corrective action of less than 30 minutes duration may be taken (according to §86.090-25), and the test continued, provided that the ambient conditions to which the vehicle is exposed are maintained at 95±5°F (35±3°C). When the engine starts, the timing sequence of the driving schedule shall begin. If failure to start is caused by vehicle malfunction and the vehicle cannot be started, the test shall be voided, the vehicle removed from the dynamometer, and corrective action may be taken according to §86.090-25. The reason for the malfunction (if determined) and the corrective action taken shall be reported to the Administrator.

(4) Provisions of §86.136-90(e) shall apply.

(e) Pressure checks. No pressure checks of the evaporative system shall be allowed. Under no circumstances will any changes/repairs to the evaporative emissions control system be allowed.

(f) Temperature stabilization. Immediately after the hot transient exhaust emission test, the vehicle shall be soaked in a temperature controlled area for a maximum of 6 hours until the fuel temperature is stabilized. The fuel may be heated or cooled to stabilize fuel temperatures, but the fuel heating rate must not exceed 5°F in any 1-hour interval during the soak period. A manufacturer may use a faster heating rate or a longer period for stabilizing fuel temperatures if the needed heating cannot be easily accomplished in the 6-hour period, subject to Administrator approval.

(1) Fuel temperatures must be held at 95 ±3°F for at least one hour before the start of the running loss test.

(2) If a vehicle's fuel temperature profile has an initial temperature lower than 95°F, as described in §86.129-94(d)(7)(v), the fuel in the test vehicle must be stabilized to within 3°F of that temperature for at least one hour before the start of the running loss test.

(g) Running loss test. The running loss test may be conducted either by the enclosure method, or by the point-source method.

(1) Enclosure method.(i) The running loss enclosure shall be purged for several minutes immediately prior to the test. Warning: If at any time the concentration of hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 ppm C the enclosure should be immediately purged. This concentration provides at least a 4:1 safety factor against the lean flammability limit.

(ii) The FID hydrocarbon analyzer shall be zeroed and spanned immediately prior to the test.

(iii) If not already on, the running loss enclosure mixing fan(s) shall be turned on at this time. Throughout the test, the mixing fan(s) shall circulate the air at a rate of at least 1.0 cfm per cubic foot of ambient volume.

(iv) The test vehicle, with the engine off, shall be moved onto the dynamometer in the running loss enclosure. The vehicle engine compartment cover shall be unlatched, but closed as much as possible, allowing for the air intake equipment specified in paragraph (g)(1)(vii) of this section. The vehicle engine compartment cover may be closed if alternate routing is found for the air intake equipment. Any windows, doors, and luggage compartments shall be closed. A window may be opened to direct cooling air into the passenger compartment of the vehicle, if the vehicle is not equipped with its own air conditioning.

(v) Fans shall be positioned as described in §§86.107-96 (d) and (h).

(vi) Set vehicle air conditioning controls as described in 40 CFR 1066.835.

(vii) Connect the air intake equipment to the vehicle, if applicable. This connection shall be made to minimize leakage.

(viii) The temperature and pressure recording systems shall be started. Measurement of vapor temperature is optional during the running loss test. If vapor temperature is not measured, fuel tank pressure need not be measured.

(ix) Turn off purge blowers (if not already off).

(x) The temperature of the liquid fuel shall be monitored and recorded at least every 15 seconds with the temperature recording system specified in §86.107-96(e).

(xi) Close and seal the enclosure doors.

(xii) When the ambient temperature is 95±5°F (35±3°C) and the fuel has been stabilized according to paragraph (f) of this section, the running loss test may begin. Measure the initial ambient temperature and pressure.

(A) Analyze enclosure atmosphere for hydrocarbons and record. This is the initial (time = 0 minutes) hydrocarbon concentration, C_HCi, required in §86.143. Hydrocarbon emissions may be sampled continuously during the test period.

(B) Analyze the enclosure atmosphere for methanol, if applicable, and record. The methanol sampling must start simultaneously with the initiation of the hydrocarbon analysis and continue for 4.0±0.5 minutes. This is the initial (time = 0 minutes) methanol concentration, C_CH3_OHi, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses.

(xiii) Start the engine and begin operation of the vehicle over the drive cycle specified in paragraph (b) of this section.

(xiv) The ambient temperature shall be maintained at 95±5°F (95±2°F on average) during the running loss test, measured at the inlet to the cooling fan in front of the vehicle; it shall be recorded at least every 60 seconds.

(xv) The fuel temperature during the dynamometer drive shall be controlled to match the fuel tank temperature profile determined in §86.129. Measured fuel temperatures must be within ±3°F of the target profile throughout the test run. Vapor temperatures, if measured, must be within ±5°F of the target profile during the first 4186 seconds of the running loss test, and within ±3°F for the remaining 120 seconds of the test run. For any vehicle complying with the test standards, vapor temperatures may be higher than the specified tolerances without invalidating test results. For testing by the Administrator, vapor temperatures may be lower than the specified tolerances without invalidating test results. If the test vehicle has more than one fuel tank, the temperatures for both fuel tanks shall follow the target profiles determined in §86.129. The control system shall be tuned and operated to provide smooth and continuous tank temperature profiles that are representative of the on-road profiles.

(xvi) Fuel tank pressure may exceed 10 inches of water during the running loss test only if the manufacturer demonstrates that vapor would not be vented to the atmosphere upon fuel cap removal. Note that this allows for temporary pressure exceedances for vehicles whose tank pressure otherwise remains below 10 inches of water.

(xvii) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned immediately prior the end of the test.

(xviii) Fresh impingers shall be installed in the methanol collection system immediately prior to the end of the test, if applicable.

(xix) The running loss test ends with the completion of the third 2-minute idle period.

(xx) At the end of the running loss test:

(A) Analyze the enclosure atmosphere for hydrocarbons and record. This is the final hydrocarbon concentration, C_HCf, required in §86.143.

(B) Analyze the enclosure atmosphere for methanol, if applicable, and record. The methanol sampling must start prior to the end of the test and continue for 4.0±0.5 minutes. The methanol sampling must be completed within 2 minutes after the end of the running loss test. This is the final methanol concentration, C_CH3_OHf, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses.

(C) Turn off all the fans specified in §86.107-96(d). Also, the time that the vehicle's engine compartment cover is open for removal of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the engine compartment.

(xxi) Turn off any CVS apparatus (if not already turned off).

(2) Point-source method. (i) The test vehicle, with the engine off, shall be moved onto the dynamometer. The vehicle engine compartment cover and any windows, doors, and luggage compartments shall be closed.

(ii) Fans shall be positioned as described in §§86.135-90(b) and §86.107-96(d).

(iii) The running loss vapor vent collection system shall be properly positioned at the potential fuel vapor vents or leaks of the vehicle's fuel system. Typical vapor vents for current fuel systems are the ports of the evaporative emission canister and the pressure relief vent of the fuel tank (typically integrated into the fuel tank cap).

(iv) The running loss vapor vent collection system may be connected to a PDP-CVS or CFV-CVS bag collection system. Otherwise, running loss vapors shall be sampled continuously with analyzers meeting the requirements of §86.107-96(b).

(v) Fans shall be positioned as described in §86.107-96(d).

(vi) Set vehicle air conditioning controls as described in 40 CFR 1066.835.

(vii) The temperature and pressure recording systems shall be started. Measurement of vapor temperature is optional during the running loss test. If vapor temperature is not measured, fuel tank pressure need not be measured.

(viii) The temperature of the liquid fuel shall be monitored and recorded at least every 15 seconds with the temperature recording system specified in §86.107-96(e).

(ix) When the ambient temperature is 95±5°F (35±3°C) and the fuel tank temperature is 95±3°F the running loss test may begin.

(x) The ambient temperature shall be maintained at 95±5°F (95±2°F on average) during the running loss test, measured at the inlet to the cooling fan in front of the vehicle; it shall be recorded at least every 60 seconds.

(xi) Fuel temperatures shall be controlled according to the specifications of paragraph (g)(1)(xv) of this section.

(xii) The tank pressure requirements described in paragraph (g)(1)(xvi) of this section apply also to running loss testing by the point source method.

(xiii) The running loss test ends with completion of the third 2-minute idle period.

(xiv) If emissions are collected in bags, the sample bags must be analyzed within 20 minutes of their respective sample collection phases, as described in §86.137-94(b)(15). The results of the analysis are used in §86.143 to calculate the mass of hydrocarbons emitted.

(xv) At the end of the running loss test, turn off all the fans specified in §86.107-96(d).

(3) With prior approval of the Administrator, manufacturers may use an alternative running loss test procedure, provided the alternative test procedure is shown to yield equivalent or superior emission results (in terms of quality control, accuracy and repeatability) for the running loss, hot soak and diurnal portions of the three diurnal-plus-hot-soak test sequence. Additionally, the Administrator may conduct certification and in-use testing using the test procedures outlined in paragraph (g)(1) of this section, paragraph (g)(2) of this section or the alternative running loss test procedure as approved for a specific vehicle.

(4) High-altitude testing. For testing under high-altitude conditions, decrease the target ambient and fuel temperatures by 5°F. For example, the fuel temperature profile should be adjusted downward based on a nominal starting temperature of 90°F, and the nominal temperature in the enclosure should be 90°F.

(h) Following the completion of the running loss drive, the vehicle may be tested for hot soak emissions as specified in §86.138-96.

[58 FR 16040, Mar. 24, 1993, as amended at 59 FR 48510, Sept. 21, 1994; 60 FR 43896, Aug. 23, 1995; 70 FR 72927, Dec. 8, 2005; 79 FR 23696, Apr. 28, 2014; 89 FR 28157, Apr. 18, 2024]

§86.135-12 Dynamometer procedure.

(a) Overview. The dynamometer run consists of two tests, a “cold” start test, after a minimum 12-hour and a maximum 36-hour soak according to the provisions of §§86.132 and 86.133, and a “hot” start test following the “cold” start by 10 minutes. Engine startup (with all accessories turned off), operation over the UDDS, and engine shutdown make a complete cold start test. Engine startup and operation over the first 505 seconds of the driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air in the dilution tunnel as shown in Figure B94-5 and Figure B94-6. A dilution tunnel is not required for testing vehicles waived from the requirement to measure particulates. Six particulate samples are collected on filters for weighing; the first sample plus backup is collected during the first 505 seconds of the cold start test; the second sample plus backup is collected during the remainder of the cold start test (including shutdown); the third sample plus backup is collected during the hot start test. Continuous proportional samples of gaseous emissions are collected for analysis during each test phase. For gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled Otto-cycle vehicles, the composite samples collected in bags are analyzed for THC, CO, CO₂, CH₄, NO_X, and N₂O. For petroleum-fueled diesel-cycle vehicles (optional for natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled diesel-cycle vehicles), THC is sampled and analyzed continuously according to the provisions of §86.110-94. Parallel samples of the dilution air are similarly analyzed for THC, CO, CO₂, CH₄, NO_X, and N₂O. For natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled vehicles, bag samples are collected and analyzed for THC (if not sampled continuously), CO, CO₂, CH₄, NO_X, and N₂O. For methanol-fueled vehicles, methanol and formaldehyde samples are taken for both exhaust emissions and dilution air (a single dilution air formaldehyde sample, covering the total test period may be collected). For ethanol-fueled vehicles, methanol, ethanol, acetaldehyde, and formaldehyde samples are taken for both exhaust emissions and dilution air (a single dilution air formaldehyde sample, covering the total test period may be collected). Parallel bag samples of dilution air are analyzed for THC, CO, CO₂, CH₄, NO_X, and N₂O.

(b) During dynamometer operation, a fixed speed cooling fan shall be positioned so as to direct cooling air to the vehicle in an appropriate manner with the engine compartment cover open. In the case of vehicles with front engine compartments, the fan shall be squarely positioned within 12 inches (30.5 centimeters) of the vehicle. In the case of vehicles with rear engine compartments (or if special designs make the above impractical), the cooling fan shall be placed in a position to provide sufficient air to maintain vehicle cooling. The fan capacity shall normally not exceed 5300 cfm (2.50 m ³/sec). However, if the manufacturer can show that during field operation the vehicle receives additional cooling, and that such additional cooling is needed to provide a representative test, the fan capacity may be increased, additional fans used, variable speed fan(s) may be used, and/or the engine compartment cover may be closed, if approved in advance by the Administrator. For example, the hood may be closed to provide adequate air flow to an intercooler through a factory installed hood scoop. Additionally, the Administrator may conduct certification, fuel economy and in-use testing using the additional cooling set-up approved for a specific vehicle.

(c) The vehicle speed as measured from the dynamometer rolls shall be used. A speed vs. time recording, as evidence of dynamometer test validity, shall be supplied on request of the Administrator.

(d) Practice runs over the prescribed driving schedule may be performed at test point, provided an emission sample is not taken, for the purpose of finding the appropriate throttle action to maintain the proper speed-time relationship, or to permit sampling system adjustment. Both smoothing of speed variations and excessive accelerator pedal perturbations are to be avoided. When using two-roll dynamometers a truer speed-time trace may be obtained by minimizing the rocking of the vehicle in the rolls; the rocking of the vehicle changes the tire rolling radius on each roll. This rocking may be minimized by restraining the vehicle horizontally (or nearly so) by using a cable and winch.

(e) The drive wheel tires may be inflated up to a gauge pressure of 45 psi (310 kPa) in order to prevent tire damage. The drive wheel tire pressure shall be reported with the test results.

(f) If the dynamometer has not been operated during the 2-hour period immediately preceding the test, it shall be warmed up for 15 minutes by operating at 30 mph (48 kph) using a non-test vehicle or as recommended by the dynamometer manufacturer.

(g) If the dynamometer horsepower must be adjusted manually, it shall be set within 1 hour prior to the exhaust emissions test phase. The test vehicle shall not be used to make this adjustment. Dynamometers using automatic control of pre-selectable power settings may be set anytime prior to the beginning of the emissions test.

(h) The driving distance, as measured by counting the number of dynamometer roll or shaft revolutions, shall be determined for the transient cold start, stabilized cold start, and transient hot start phases of the test. The revolutions shall be measured on the same roll or shaft used for measuring the vehicle's speed.

(i) Four-wheel drive and all-wheel drive vehicles may be tested either in a four-wheel drive or a two-wheel drive mode of operation. In order to test in the two-wheel drive mode, four-wheel drive and all-wheel drive vehicles may have one set of drive wheels disengaged; four-wheel and all-wheel drive vehicles which can be shifted to a two-wheel mode by the driver may be tested in a two-wheel drive mode of operation.

[75 FR 25679, May 7, 2010, as amended at 77 FR 63152, Oct. 15, 2012]

§86.135-90 Dynamometer procedure.

(a) The dynamometer run consists of two tests - a “cold” start test, after a minimum 12-hour and a maximum 36-hour soak according to the provisions of §§86.132 and 86.133, and a “hot” start test following the “cold” start by 10 minutes. Engine startup (with all accessories turned off), operation over the UDDS and engine shutdown make a complete cold-start test. Engine startup and operation over the first 505 seconds of the driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air in the dilution tunnel as shown in Figure B94-5 and Figure B94-6. A dilution tunnel is not required for testing vehicles waived from the requirement to measure particulate matter. Six particulate samples are collected on filters for weighing; the first sample plus backup is collected during the first 505 seconds of the cold-start test; the second sample plus backup is collected during the remainder of the cold-start test (including shutdown); the third sample plus backup is collected during the hot start test. Continuous or batch proportional samples of gaseous emissions are collected for analysis during each test phase. Use the following measurement procedures for each type of engine:

(1) For gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled Otto-cycle vehicles, the composite samples collected in bags are analyzed for THC, CO, CO₂, CH₄, and NO_X.

(2) For petroleum-fueled diesel-cycle vehicles (optional for natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled diesel-cycle vehicles), THC is sampled and analyzed continuously according to the provisions of §86.110. Parallel samples of the dilution air are similarly analyzed for THC, CO, CO₂, CH₄, and NO_X.

(3) For natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled vehicles, bag samples are collected and analyzed for THC (if not sampled continuously), CO, CO₂, CH₄, and NO_X.

(4) For methanol-fueled vehicles, methanol and formaldehyde samples are taken for both exhaust emissions and dilution air (a single dilution air formaldehyde sample, covering the total test period may be collected). Parallel bag samples of dilution air are analyzed for THC, CO, CO₂, CH₄, and NO_X.

(b) During dynamometer operation, a fixed speed cooling fan shall be positioned so as to direct cooling air to the vehicle in an appropriate manner with the engine compartment cover open. In the case of vehicles with front engine compartments, the fan shall be squarely positioned within 12 inches (30.5 centimeters) of the vehicle. In the case of vehicles with rear engine compartments (or if special designs make the above impractical), the cooling fan shall be placed in a position to provide sufficient air to maintain vehicle cooling. The fan capacity shall normally not exceed 5300 cfm (2.50 m3/sec). If however, the manufacturer can show that during field operation the vehicle receives additional cooling, and that such additional cooling is needed to provide a representative test, the fan capacity may be increased, additional fans used, variable speed fan(s) may be used, and/or the engine compartment cover may be closed if approved in advance by the Administrator. For example, the hood may be closed to provide adequate air flow to an intercooler through a factory installed hood scoop. Additionally, the Administrator may conduct certification, fuel economy and in-use testing using the additional cooling set-up approved for a specific vehicle.

(c) The vehicle speed as measured from the dynamometer rolls shall be used. A speed vs. time recording, as evidence of dynamometer test validity, shall be supplied on request of the Administrator.

(d) Practice runs over the prescribed driving schedule may be performed at test point, provided an emission sample is not taken, for the purpose of finding the appropriate throttle action to maintain the proper speed-time relationship, or to permit sampling system adjustment. Both smoothing of speed variations and excessive accelerator pedal perturbations are to be avoided. When using two-roll dynamometers a truer speed-time trace may be obtained by minimizing the rocking of the vehicle in the rolls; the rocking of the vehicle changes the tire rolling radius on each roll. This rocking may be minimized by restraining the vehicle horizontally (or nearly so) by using a cable and winch.

(e) The drive wheel tires may be inflated up to a gauge pressure of 45 psi (310 kPa) in order to prevent tire damage. The drive wheel tire pressure shall be reported with the test results.

(f) lf the dynamometer has not been operated during the 2-hour period immediately preceding the test, it shall be warmed up for 15 minutes by operating at 30 mph (48 kph) using a non-test vehicle or as recommended by the dynamometer manufacturer.

(g) If the dynamometer horsepower must be adjusted manually, it shall be set within 1 hour prior to the exhaust emissions test phase. The test vehicle shall not be used to make this adjustment. Dynamometers using automatic control of preselectable power settings may be set anytime prior to the beginning of the emissions test.

(h) The driving distance, as measured by counting the number of dynamometer roll or shaft revolutions, shall be determined for the transient cold start, stabilized cold start, and transient hot start phases of the test. The revolutions shall be measured on the same roll or shaft used for measuring the vehicle's speed.

(i) Four-wheel drive and all-wheel drive vehicles may be tested either in a four-wheel drive or a two-wheel drive mode of operation. In order to test in the two-wheel drive mode, four-wheel drive and all-wheel drive vehicles may have one set of drive wheels disengaged; four-wheel and all-wheel drive vehicles which can be shifted to a two-wheel mode by the driver may be tested in a two-wheel drive mode of operation.

[54 FR 14529, Apr. 11, 1989, as amended at 70 FR 72927, Dec. 8, 2005; 74 FR 61547, Nov. 25, 2009; 79 FR 23697, Apr. 28, 2014]

§86.136-90 Engine starting and restarting.

(a) Otto-cycle vehicles. Paragraph (a) of this section applies to Otto-cycle vehicles.

(1) The engine shall be started according to the manufacturer's recommended starting procedures in the owner's manual. The initial 20-second idle period shall begin when the engine starts.

(2) Choke operation: (i) Vehicles equipped with automatic chokes shall be operated according to the manufacturer's operating instructions in the owner's manual, including choke setting and “kick-down” from cold fast idle.

(ii) Vehicles equipped with manual chokes shall be operated according to the manufacturer's operating instructions in the owner's manual.

(3) The transmission shall be placed in gear 15 seconds after the engine is started. If necessary, braking may be employed to keep the drive wheels from turning.

(4) The operator may use the choke, accelerator pedal, etc., where necessary to keep the engine running.

(5) If the manufacturer's operating instructions in the owner's manual do not specify a warm engine starting procedure, the engine (automatic and manual-choke engines) shall be started by depressing the accelerator pedal about half way and cranking the engine until it starts.

(b) Diesel vehicles. The engine shall be started according to the manufacturers recommended starting procedures in the owners manual. The initial 20-second idle period shall begin when the engine starts. The transmission shall be placed in gear 15 seconds after the engine is started. If necessary, braking may be employed to keep the drive wheels from turning.

(c) If the vehicle does not start after the manufacturer's recommended cranking time (or 10 continuous seconds in the absence of a manufacturer's recommendation), cranking shall cease for the period recommended by the manufacturer (or 10 seconds in the absence of a manufacturer's recommendation). This may be repeated for up to three start attempts. If the vehicle does not start after three attempts, the reason for failure to start shall be determined. The gas flow measuring device on the constant volume sampler (usually a revolution counter) or CFV (and the hydrocarbon integrator and particulate sampling system when testing petroleum-fueled diesel vehicles and the particulate sampling system when testing methanol-fueled diesel vehicles, see §86.137) shall be turned off and the sampler selector valves, including the methanol sampler, placed in the “standby” position during this diagnostic period. In addition, either the CVS should be turned off, or the exhaust tube disconnected from the tailpipe during the diagnostic period. If failure to start is an operational error, the vehicle shall be rescheduled for testing from a cold start.

(d) If the engine “false starts” the operator shall repeat the recommended starting procedure (such as resetting the choke, etc.).

(e) Stalling. (1) If the engine stalls during an idle period, the engine shall be restarted immediately and the test continued. If the engine cannot be started soon enough to allow the vehicle to follow the next acceleration as prescribed, the driving schedule indicator shall be stopped. When the vehicle restarts, the driving schedule indicator shall be reactivated.

(2) If the engine stalls during some operating mode other than idle, the driving schedule indicator shall be stopped, the vehicle shall then be restarted and accelerated to the speed required at that point in the driving schedule and the test continued. During acceleration to this point, shifting shall be performed in accordance with §86.128.

(3) If the vehicle will not restart within one minute, the test shall be voided, the vehicle removed from the dynamometer, corrective action taken, and the vehicle rescheduled for test. The reason for the malfunction (if determined) and the corrective action taken shall be reported to the Administrator.

[54 FR 14530, Apr. 11, 1989, as amended at 58 FR 16042, Mar. 24, 1993; 59 FR 48510, Sept. 21, 1994]

§86.137-94 Dynamometer test run, gaseous and particulate emissions.

Section 86.137-94 includes text that specifies requirements that differ from §86.137-90. Where a paragraph in §86.137-90 is identical and applicable to §86.137-94, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see §86.137-90.” Where a corresponding paragraph of §86.137-90 is not applicable, this is indicated by the statement “[Reserved].”

(a) General. The dynamometer run consists of two tests, a cold start test, after a minimum 12-hour and a maximum 36-hour soak according to the provisions of §86.132, and a hot start test following the cold start test by 10 minutes. The vehicle shall be stored prior to the emission test in such a manner that precipitation (e.g., rain or dew) does not occur on the vehicle. The complete dynamometer test consists of a cold start drive of 7.5 miles (12.1 km) and simulates a hot start drive of 7.5 miles (12.1 km). The vehicle is allowed to stand on the dynamometer during the 10 minute time period between the cold and hot start tests. The cold start test is divided into two periods. The first period, representing the cold start “transient” phase, terminates at the end of the deceleration which is scheduled to occur at 505 seconds of the driving schedule. The second period, representing the “stabilized” phase, consists of the remainder of the driving schedule including engine shutdown. The hot start test, similarly, consists of two periods. The first period, representing the hot start “transient” phase, terminates at the same point in driving schedule as the first period of the cold start test. The second period of the hot start test, “stabilized” phase, is assumed to be identical to the second period of the cold start test. Therefore, the hot start test terminates after the first period (505 seconds) is run.

(b) The following steps shall be taken for each test:

(1) Place drive wheels of vehicle on dynamometer without starting engine.

(2) Open the vehicle engine compartment cover and position the cooling fan.

(3) For all vehicles, with the sample selector valves in the “standby” position, connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems.

(4) For methanol-fueled vehicles, with the sample selector valves in the “standby” position, insert fresh sample collection impingers into the methanol sample collection system, fresh impingers or a fresh cartridge into the formaldehyde sample collection system and fresh impingers (or a single cartridge for formaldehyde) into the dilution air sample collection systems for methanol and formaldehyde (background measurements of methanol and formaldehyde may be omitted and concentrations assumed to be zero for calculations in §86.144).

(5) Start the CVS (if not already on), the sample pumps (except the particulate sample pump, if applicable), the temperature recorder, the vehicle cooling fan, and the heated THC analysis recorder (diesel-cycle only). (The heat exchanger of the constant volume sampler, if used, petroleum-fueled diesel-cycle THC analyzer continuous sample line and filter, methanol-fueled vehicle THC, methanol and formaldehyde sample lines, if applicable, should be preheated to their respective operating temperatures before the test begins).

(6) Adjust the sample flow rates to the desired flow rate and set the gas flow measuring devices to zero.

(i) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17 cfm (0.08 1/sec).

(ii) For THC samples, the minimum FID (or HFID in the case of diesel-cycle and methanol-fueled Otto-cycle vehicles) flow rate is 0.066 cfm (0.031 1/sec).

(iii) For methanol samples, the flow rates shall be set such that the system meets the design criteria of §86.109 and §86.110. For samples in which the concentration in the primary impinger exceeds 0.5 mg/l, it is recommended that the mass of methanol collected in the secondary impinger not exceed ten percent of the total mass collected. For samples in which the concentration in the primary impinger does not exceed 0.5 mg/l, analysis of the secondary impingers is not necessary.

(iv) For formaldehyde samples, the flow rates shall be set such that the system meets the design criteria of §86.109 and §86.110. For impinger samples in which the concentration of formaldehyde in the primary impinger exceeds 0.1 mg/l, it is recommended that the mass of formaldehyde collected in the secondary impinger not exceed ten percent of the total mass collected. For samples in which the concentration in the primary impinger does not exceed 0.1 mg/l, analysis of the secondary impingers is not necessary.

(7) Attach the exhaust tube to the vehicle tailpipe(s).

(8) Carefully install a particulate sample filter into each of the filter holders. The filters must be handled only with forceps or tongs. Rough or abrasive filter handling will result in erroneous weight determination.

(9) Start the gas flow measuring device, position the sample selector valves to direct the sample flow into the “transient” exhaust sample bag, the “transient” methanol exhaust sample, the “transient” formaldehyde exhaust sample, the “transient” dilution air sample bag, the “transient” methanol dilution air sample and the “transient” formaldehyde dilution air sample (turn on the petroleum-fueled diesel-cycle THC analyzer system integrator, mark the recorder chart, start particulate sample pump No. 1, and record both gas meter or flow measurement instrument readings, if applicable), turn the key on, and start cranking the engine.

(10) Fifteen seconds after the engine starts, place the transmission in gear.

(11) Twenty seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule.

(12) Operate the vehicle according to the Urban Dynamometer Driving Schedule (§86.115).

Note:

During particulate testing, adjust the flow rate through the particulate sample probe to maintain a constant value within ±5 percent of the set flow rate. Record the average temperature and pressure at the gas meter or flow instrument inlet. If the set flow rate cannot be maintained because of high particulate loading on the filter, the test shall be terminated. The test shall be rerun using a lower flow rate, or larger diameter filter, or both.

(13) At the end of the deceleration which is scheduled to occur at 505 seconds, simultaneously switch the sample flows from the “transient” bags and samples to the “stabilized” bags and samples, switch off gas flow measuring device No. 1, switch off the No. 1 petroleum-fueled diesel hydrocarbon integrator and the No. 1 particulate sample pump, mark the petroleum-fueled diesel hydrocarbon recorder chart, and close valves isolating particulate filter No. 1, if applicable, start gas flow measuring device No. 2, and start the petroleum-fueled diesel hydrocarbon integrator No. 2 and the No. 2 particulate sample pump and open valves isolating particulate filter No. 2, if applicable. Before the acceleration which is scheduled to occur at 510 seconds, record the measured roll or shaft revolutions and reset the counter or switch to a second counter. As soon as possible transfer the “transient” exhaust and dilution air samples to the analytical system and process the samples according to §86.140 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample collection phase of the test.

(14) Turn the engine off 2 seconds after the end of the last deceleration (at 1,369 seconds).

(15) Five seconds after the engine stops running, simultaneously turn off gas flow measuring device No. 2 and if applicable, turn off the hydrocarbon integrator No. 2, mark the hydrocarbon recorder chart, turn off the No. 2 particulate sample pump and close the valves isolating particulate filter No. 2, and position the sample selector valves to the “standby” position (and open the valves isolating particulate filter No. 1, if applicable). Record the measured roll or shaft revolutions (both gas meter or flow measurement instrumentation readings), and reset the counter. As soon as possible, transfer the “stabilized” exhaust and dilution air samples to the analytical system and process the samples according to §86.140, obtaining a stabilized reading of the exhaust bag sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample period. (If it is not possible to perform analysis on the methanol and formaldehyde samples within 24 hours, the samples should be stored in a dark cold (4-10°C) environment until analysis. The samples should be analyzed within fourteen days.) If applicable, carefully remove both pairs of particulate sample filters from their respective holders, and place each in a separate petri dish, and cover.

(16) Immediately after the end of the sample period, turn off the cooling fan and close the engine compartment cover.

(17) Turn off the CVS or disconnect the exhaust tube from the tailpipe(s) of the vehicle.

(18) Repeat the steps in paragraphs (b)(2) through (b)(12) of this section for the hot start test, except only two evacuated sample bags, two methanol sample impingers, two formaldehyde sample impingers, and one pair of particulate sample filters, as appropriate, are required. The step in paragraph (b)(9) of this section shall begin between 9 and 11 minutes after the end of the sample period for the cold-start test.

(19) At the end of the deceleration scheduled to occur at 505 seconds, simultaneously turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1; mark the petroleum-fueled diesel hydrocarbon recorder chart and turn off the No. 1 particulate sample pump, if applicable) and position the sample selector valve to the “standby” position. (Engine shutdown is not part of the hot start test sample period.) Record the measured roll or shaft revolutions (and the No. 1 gas meter reading or flow measurement instrument). Carefully remove the third pair of particulate sample filters from the holder and place in a clean petri dish and cover, if applicable.

(20) As soon as possible, transfer the hot start “transient” exhaust and dilution air samples to the analytical system and process the samples according to §86.140, obtaining a stabilized reading of the exhaust bag sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample period. If it is not possible to perform analysis on the methanol and formaldehyde samples within 24 hours, the samples should be stored in a dark, cold (4-10°C) environment until analysis. Analyze the samples within fourteen days.

(21) As soon as possible, and in no case longer than one hour after the end of the hot start phase of the test, transfer the six particulate filters to the weighing chamber for post-test conditioning, if applicable.

(22) Disconnect the exhaust tube from the vehicle tailpipe(s) and drive the vehicle from dynamometer.

(23) The CVS or CFV may be turned off, if desired.

(24) This completes the test sequence for vehicles that do not need testing for evaporative emissions. Continue testing for evaporative emissions as follows:

(i) For the three-day diurnal test sequence, proceed according to §86.134.

(ii) For the two-day diurnal test sequence, proceed according to §86.138-96(k). The following additional provisions apply for heavy-duty vehicles:

(A) For vehicles with a nominal fuel tank capacity at or above 50 gallons, operate the vehicle over a second full FTP cycle before measuring evaporative emissions; exhaust emission measurement is not required for the additional FTP cycle.

(B) [Reserved]

[56 FR 25776, June 5, 1991, as amended at 60 FR 34347, June 30, 1995; 79 FR 23697, Apr. 28, 2014; 88 FR 4475, Jan. 24, 2023]

§86.138-96 Hot soak test.

(a)(1) Gasoline- and methanol-fueled vehicles. For gasoline- and methanol-fueled vehicles, the hot soak test shall be conducted immediately following the running loss test. However, sampling of emissions from the running loss test is not required as preparation for the hot soak test.

(2) Gaseous-fueled vehicles. Since gaseous-fueled vehicles are not required to perform a running loss test, the hot soak test shall be conducted within seven minutes after completion of the hot start exhaust test.

(b) The hot soak test may be conducted in the running loss enclosure as a continuation of that test or in a separate enclosure.

(1) If the hot soak test is conducted in the running loss enclosure, the driver may exit the enclosure after the running loss test. If exiting, the driver should use the personnel door described in §86.107-96(a)(2), exiting as quickly as possible with a minimum disturbance to the system. The final hydrocarbon and methanol concentration for the running loss test, measured in §86.134-96(g)(1)(xx), shall be the initial hydrocarbon and methanol concentration (time = 0 minutes) C_HCi and C_CH3_OHi, for the hot soak test.

(2) If the vehicle must be moved to a different enclosure, the following steps must be taken:

(i) The enclosure for the hot soak test shall be purged for several minutes prior to completion of the running loss test. WARNING: If at any time the concentration of hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 ppm C the enclosure should be immediately purged. This concentration provides at least a 4:1 safety factor against the lean flammability limit.

(ii) The FID hydrocarbon analyzer shall be zeroed and spanned immediately prior to the test.

(iii) Fresh impingers shall be installed in the methanol sample collection system immediately prior to the start of the test, if applicable.

(iv) If not already on, the mixing fan(s) shall be turned on at this time. Throughout the hot soak test, the mixing fan(s) shall circulate the air at a rate of 0.8±0.2 cfm per cubic foot of the nominal enclosure volume.

(v) Begin sampling as follows:

(A) Analyze the enclosure atmosphere for hydrocarbons and record. This is the initial (time = 0 minutes) hydrocarbon concentration, C_HCi, required in §86.143. Hydrocarbon emissions may be sampled continuously during the test period.

(B) Analyze the enclosure atmosphere for methanol, if applicable, and record. The methanol sampling must start simultaneously with the initiation of the hydrocarbon analysis and continue for 4.0±0.5 minutes. This is the initial (time = 0 minutes) methanol concentration, C_CH3_OHi, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses.

(vi) The vehicle engine compartment cover shall be closed (if not already closed), the cooling fan shall be moved, the vehicle shall be disconnected from the dynamometer and any sampling system, and then driven at minimum throttle to the enclosure for the hot soak test. These steps should be done as quickly as possible to minimize the time needed to start the hot soak test.

(vii) The vehicle's engine must be stopped before any part of the vehicle enters the enclosure.

(viii) The vehicle shall enter the enclosure; the enclosure doors shall be closed and sealed within 2 minutes of engine shutdown and within seven minutes after the end of the running loss test.

(ix) The test vehicle windows and any luggage compartments shall be opened (if not already open). The vehicle engine compartment cover shall be closed (if not already closed).

(c) [Reserved]

(d) The temperature recording system shall be started and the time of engine shutoff shall be noted on the evaporative emission hydrocarbon data recording system.

(e) For the first 5 minutes of the hot soak test, the ambient temperature shall be maintained at 95±10°F. For the remainder of the hot soak test, the ambient temperature shall be maintained at 95±5°F (95±2°F on average).

(f) The 60±0.5 minute hot soak begins when the enclosure doors are sealed (or when the running loss test ends, if the hot soak test is conducted in the running loss enclosure).

(g) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned immediately prior to the end of the test.

(h) Fresh impingers shall be installed in the methanol collection system immediately prior to the end of the test, if applicable.

(i) [Reserved]

(j) At the end of the 60±0.5 minute test period:

(1) Analyze the enclosure atmosphere for hydrocarbons and record. This is the final (time = 60 minutes) hydrocarbon concentration, C_HCf, required in §86.143.

(2) Analyze the enclosure atmosphere for methanol and record, if applicable. The methanol sampling must start simultaneously with the initiation of the hydrocarbon analysis and continue for 4.0±0.5 minutes. This is the final (time = 60 minutes) methanol concentration, C_CH3_OHf, required in §86.143. Record the time elapsed during this analysis. If the 4-minute sample period is inadequate to collect a sample of sufficient concentration to allow accurate GC analysis, rapidly collect the methanol sample in a bag and then bubble the bag sample through the impingers at the specified flow rate. The time elapsed between collection of the bag sample and flow through the impingers should be minimized to prevent any losses.

(k) For the supplemental two-diurnal test sequence (see§86.130-96), perform a hot soak test as described in this section, except that the test shall be conducted within seven minutes after completion of the hot start exhaust test and temperatures throughout the hot soak measurement period must be between 68° and 86°F. This hot soak test is followed by two consecutive diurnal heat builds, described in §86.133-96(p).

(l) If the vehicle is to be tested for diurnal emissions, follow the procedure outlined in §86.133-96.

[58 FR 16042, Mar. 24, 1993, as amended at 59 FR 48510, Sept. 21, 1994; 60 FR 43897, Aug. 23, 1995; 75 FR 22980, Apr. 30, 2010]

§86.139-90 Particulate filter handling and weighing.

(a) At least 8 hours, but not more than 56 hours before the test, place each filter in an open, but protected, petri dish and place in the weighing chamber which meets the humidity and temperature specifications of §86.112.

(b) At the end of the 8 to 56 hour stabilization period, weigh the filter on a balance having a precision of one microgram. Record this weight. This reading is the tare weight.

(c) The filter shall then be stored in a covered petri dish which shall remain in the weighing chamber until needed for testing.

(d)(1) If the filter is not used within one hour of its removal from the weighing chamber, it shall be reweighed.

(2) The one hour limit may be replaced by an eight-hour limit if one or both of the following conditions are met:

(i) A stabilized filter is placed and kept in a sealed filter holder assembly with the ends plugged, or

(ii) A stabilized filter is placed in a sealed filter holder assembly, which is then immediately placed in a sample line through which there is no flow.

(e) After the test, and after the sample filter is returned to the weighing room, condition it for at least 1 hour but not more than 56 hours. Then weigh a second time. This latter reading is the gross weight of the filter. Record this weight.

(f) The net weight (P_e) is the gross weight minus the tare weight.

Note:

Should the sample on the filter contact the petri dish or any other surface, the test is void and must be rerun.

[54 FR 14532, Apr. 11, 1989]

§86.140-94 Exhaust sample analysis.

The following sequence shall be performed in conjunction with each series of measurements:

(a) For CO, CO₂, CH₄, NO_X, and for Otto-cycle and methanol-fueled, natural gas-fueled and liquefied petroleum gas-fueled (if non-heated FID option is used) diesel vehicle HC:

(1) Zero the analyzers and obtain a stable zero reading. Recheck after tests.

(2) Introduce span gases and set instrument gains. In order to avoid errors, span and calibrate at the same flow rates used to analyze the test sample. Span gases should have concentrations equal to 75 to 100 percent of full scale. If gain has shifted significantly on the analyzers, check the calibrations. Show actual concentrations on chart.

(3) Check zeroes; repeat the procedure in paragraphs (a) (1) and (2) of this section if required.

(4) Check flow rates and pressures.

(5) Measure THC, CO, CO₂, CH₄, and NO_X concentrations of samples.

(6) Check zero and span points. If difference is greater than 2 percent of full scale, repeat the procedure in paragraphs (a) (1) through (5) of this section.

(b) For petroleum-fueled, natural gas-fueled and liquefied petroleum gas-fueled (if HFID is used) diesel vehicle HC:

(1) Zero HFID analyzer and obtain a stable zero reading.

(2) Introduce span gas and set instrument gains. Span gas should have concentration equal to 75 to 100 percent of full scale.

(3) Check zero as in paragraph (b)(1) of this section.

(4) Introduction of zero and span gas into the analyzer can be accomplished by either of the following methods:

(i) Close heated valve in THC sample (see Figures B94-5 or B94-6) and allow gases to enter HFID. Extreme care should be taken not to introduce gases under high pressure.

(ii) Connect zero and span line directly to THC sample probe and introduce gases at a flow rate greater than 125 percent of the HFID flow rate with the CVS blower operating (see Figures B94-5 or B94-6). Excess flow must be allowed to exit probe inlet.

Note:

In order to minimize errors, HFID flow rate and pressure during zero and span (and background bag reading) must be exactly the same as that used during testing.

(5) Continuously record (integrate electronically if desired) dilute THC emission levels during test. Background samples are collected in sample bags and analyzed as in paragraphs (b)(4) (i) or (ii) of this section.

(6) Check zero and span as in paragraphs (b) (1) through (4) of this section. If difference is greater than 2 percent of full scale, void test and check for THC “hangup” or electronic drift in analyzer.

(c) For CH₃OH (methanol-fueled vehicles), introduce test samples into the gas chromatograph and measure the concentration. This concentration is C_MS in the calculations.

(d) For HCHO (methanol-fueled vehicles), introduce formaldehyde test samples into the high pressure liquid chromatograph and measure the concentration of formaldehyde as a dinitrophenylhydrazine derivative in acetonitrile. This concentration is C_FS in the calculations.

(e) For CH₄ analysis:

(1) In the event that the procedure results in negative NMHC_wm values (as may occur with high methane fractions), any negative NMHC_wm value whose absolute value is less than 10 percent of the NMHC standard shall be rounded to zero. Negative NMHC_wm values whose absolute value is more than 10 percent of the NMHC standard shall require sample remeasurement. If the 10 percent criterion cannot be met after remeasurement, the test will be void.

(2) Other sampling procedures may be used if shown to yield equivalent or superior results and if approved in advance by the Administrator.

[56 FR 25777, June 5, 1991, as amended at 59 FR 48510, Sept. 21, 1994; 60 FR 34347, June 30, 1995]

§86.142-90 Records required.

The following information shall be recorded with respect to each test:

(a) Test number.

(b) System or device tested (brief description).

(c) Date and time of day for each part of the test schedule.

(d) Test results. Also include a comparison of drive cycle energy and target cycle energy relative to both inertia and road load forces as specified in 40 CFR 1066.425 for each drive cycle or test phase, as appropriate.

(e) Driver and equipment operator IDs.

(f) Vehicle. ID number, manufacturer, model year, standards, engine family, evaporative emissions family, basic engine description (including displacement, number of cylinders, turbo-/supercharger used, and catalyst usage), fuel system (including number of carburetors, number of carburetor barrels, fuel injection type, and fuel tank(s) capacity and location), engine code, gross vehicle weight rating, inertia weight class, actual curb weight at zero miles, actual road load at 50 mph (80 kph), transmission configuration, axle ratio, car line, system miles, idle rpm, and drive wheel tire pressure, as applicable.

(g) Dynamometer. Dynamometer ID, inertia weight setting, indicated power absorption setting, records to verify compliance with the vehicle speed versus time requirements of the test, and driving distance for each of the three phases of the test, calculated from the measured roll or shaft revolutions.

(h) Gas analyzers. Analyzer bench ID, analyzer ranges, recordings of analyzer output during zero, span, and sample readings.

(i) Recorder charts: Test number, date, vehicle ID, operator ID, and identification of the measurements recorded.

(j) Test cell barometric pressure, ambient temperature, and humidity.

Note:

A central laboratory barometer may be used: Provided, that individual test cell barometric pressures are shown to be within ±0.1 percent of the barometric pressure at the central barometer location.

(k) Temperatures. Records to verify compliance with the ambient temperature requirements throughout the test procedure and recordings of vehicle fuel temperature(s) during the diurnal test and of the enclosure temperatures during the diurnal and hot soak tests.

(l) CFV-CVS. Total dilute exhaust volume (Vmix) for each phase of the exhaust test.

(m) PDP-CVS. Test measurements required to calculate the Vmix. Total dilute exhaust volume (Vmix) for each phase of the exhaust test.

(n) The humidity of the dilution air.

Note:

If conditioning columns are not used (see §§86.122 and 86.144) this measurement can be deleted. If the conditioning columns are used and the dilution air is taken from the test cell, the ambient humidity can be used for this measurement.

(o) Additional records required for diesel vehicles. (1) Pressure and temperature of the dilute exhaust mixture (and background air if sampled) at the inlet to the gas meter used for particulate sampling.

(2) The temperature of the dilute exhaust mixture inside the dilution tunnel near the inlet of the particulate probe.

(3) The temperature of the gas flowing in the heated sample line before the heated filter, and also before the HFID, and the temperature of the control system of the heated hydrocarbon detector.

(4) Gas meter or flow measurement instrumentation readings at the start of each sample period and at the end of each sample period.

(5) The stabilized pre-test weight and post-test weight of each particulate sample and back-up filter.

(6) Continuous temperature and humidity recording of the ambient air in which the particulate filters were stabilized.

(p) Additional required records for methanol-fueled vehicles. (1) Specification of the methanol-fuel or methanol-fuel mixtures used during the test.

(2) Volume of sample passed through the methanol sampling system and the volume of deionized water in each impinger.

(3) The concentration of the GC analyses of the test samples (methanol).

(4) Volume of sample passed through the formaldehyde sampling system and the volume of DNPH solution used.

(5) The concentration of the HPLC analysis of the test sample (formaldehyde).

(6) The temperatures of the sample lines before the HFID and the impinger, the temperature of the exhaust transfer duct (as applicable), and the temperature of the control system of the heated hydrocarbon detector.

(7) A continuous measurement of the dew point of the raw and diluted exhaust. This requirement may be omitted if the temperatures of all heated lines are kept above 220°F, or if the manufacturer performs an engineering analysis demonstrating that the temperature of the heated systems remains above the maximum dew point of the gas stream throughout the course of the test.

(q) Additional required records for natural gas-fueled vehicles. Composition, including all carbon containing compounds; e.g. CO₂, of the natural gas-fuel used during the test. C₁ and C₂ compounds shall be individually reported. C₃ and heavier hydrocarbons, and C₆ and heavier compounds may be reported as a group.

(r) Additional required records for liquefied petroleum gas-fueled vehicles. Composition of the liquefied petroleum gas-fuel used during the test. Each hydrocarbon compound present, through C₄ compounds, shall be individually reported. C₅ and heavier hydrocarbons may be reported as a group.

[54 FR 14533, Apr. 11, 1989, as amended at 58 FR 58422, Nov. 1, 1993; 59 FR 48510, Sept. 21, 1994; 60 FR 34348, June 30, 1995; 79 FR 23697, Apr. 28, 2014]

§86.143-96 Calculations; evaporative emissions.

(a) The following equations are used to calculate the evaporative emissions from gasoline- and methanol-fueled vehicles, and for gaseous-fueled vehicles.

(b) Use the measurements of initial and final concentrations to determine the mass of hydrocarbons and methanol emitted. For testing with pure gasoline, methanol emissions are assumed to be zero.

(1) For enclosure testing of diurnal, hot soak, and running loss emissions:

(i) Methanol emissions:

Where:

M_CH3OH = Methanol mass change, μg.

V_n = Net enclosure volume, ft ³ , as determined by subtracting 50 ft ³ (volume of vehicle with trunk and windows open) from the enclosure volume. A manufacturer may use the measured volume of the vehicle (instead of the nominal 50 ft ³) with advance approval by the Administrator: Provided, the measured volume is determined and used for all vehicles tested by that manufacturer.

TE = Temperature of sample withdrawn, R.

f = Final sample.

C_MS = GC concentration of sample, μg/ml.

1 = First impinger.

AV = Volume of absorbing reagent in impinger.

2 = Second impinger.

V_E = Volume of sample withdrawn, ft ³ . Sample volumes must be corrected for differences in temperature to be consistent with determination of V_n, prior to being used in the equation.

T_SHED = Temperature of SHED, R.

i = Initial sample.

M_CH3OH,out = mass of methanol exiting the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, μg.

M_CH3OH,in = mass of methanol entering the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, μg.

(ii) Hydrocarbon emissions:

Where,

(A) M_HC = Hydrocarbon mass change, g.

(B) C_HC = FID hydrocarbon concentration as ppm including FID response to methanol (or methane, as appropriate) in the sample.

(C) C_CH3OH = Methanol concentration as ppm carbon.

(D) V_n = Net enclosure volume ft ³ (m ³) as determined by subtracting 50 ft ³ (1.42 m ³) (volume of vehicle with trunk and windows open) from the enclosure volume. A manufacturer may use the measured volume of the vehicle (instead of the nominal 50 ft ³) with advance approval by the Administrator, provided the measured volume is determined and used for all vehicles tested by that manufacturer.

(E) r = FID response factor to methanol.

(F) P_B = Barometric pressure, in Hg (Kpa).

(G) T = Enclosure temperature,°R(°K).

(H) i = initial reading.

(I) f = final reading.

(J) 1 = First impinger.

(K) 2 = Second impinger.

(L) Assuming a hydrogen to carbon ratio of 2.3:

(1) k = 2.97; and

(2) For SI units, k = 17.16.

(M) M_{HC, out} = mass of hydrocarbons exiting the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, g.

(N) M_{HC, in} = mass of hydrocarbons entering the enclosure, in the case of fixed-volume enclosures for diurnal emission testing, g.

(iii) For variable-volume enclosures, defined in §86.107(a)(1)(i), the following simplified form of the hydrocarbon mass change equation may be used:

(2) For running loss testing by the point-source method, the mass emissions of each test phase are calculated below, then summed for a total mass emission for the running loss test. If emissions are continuously sampled, the following equations can be used in integral form.

(i) Methanol emissions:

M_CH3_OH = ρ_CH3_OH V_mix ×

(C_CH3_{OH, rl}−C_CH3_{OH, d})

Where,

(A) M_CH3_OH = methanol mass change, µg.

(B) ρ_CH3,_OH = 37.71 g/ft ³, density of pure vapor at 68°F.

(C) V_mix = total dilute sample volume, in ft ³, calculated as appropriate for the collection technique used.

(D) C_CH3_{OH, rl} = methanol concentration of diluted running loss sample, in ppm carbon equivalent.

(E) C_CH3_{OH, d} = methanol concentration of dilution air, in ppm carbon equivalent.

(ii) Hydrocarbon emissions:

M_HC = ρ_HC V_mix10⁻⁶ × (C_{HC, rl}−C_{HC, d})

Where,

(A) M_HC = hydrocarbon mass change, g.

(B) ρ_HC = 16.88 g/ft ³, density of pure vapor at 68°F (for hydrogen to carbon ratio of 2.3).

(C) V_mix = total dilute sample volume, in ft ³, calculated as appropriate for the collection technique used.

(D) C_{HC, rl} = hydrocarbon concentration of diluted running loss sample, in ppm carbon equivalent.

(E) C_{HC, d} = hydrocarbon concentration of dilution air, in ppm carbon equivalent.

(c) If the test fuel contains at least 25% oxygenated compounds by volume, measure the concentration of oxygenated compounds directly using a photoacoustic analyzer specified in 40 CFR 1065.269 or using impingers as described in 40 CFR 1065.805(f). Calculate total hydrocarbon equivalent emissions with the following equation, using density values specified in 40 CFR 1066.1005(f):

Where:

m_THCE = the sum of the mass of THCE in the SHED.

m_THC = the mass of THC and all oxygenated hydrocarbons in the SHED, as measured by the FID. Calculate THC mass based on ρ_THC.

r_THC = the effective C₁-equivalent density of THC as specified in 40 CFR 1066.1005(f).

m_OHCi = the mass of oxygenated species i in the SHED.

r_OHCi = the C₁-equivalent density of oxygenated species i.

RF_{OHCi[THC-FID]} = the response factor of a THC-FID to oxygenated species i relative to propane on a C₁-equivalent basis as determined in 40 CFR 1065.845.

(d)(1) For the full three-diurnal test sequence, there are two final results to report:

(i) The sum of the adjusted total mass emissions for the diurnal and hot soak tests (M_DI + M_HS); and

(ii) The adjusted total mass emissions for the running loss test, on a grams per mile basis = M_RL/D_RL, where D_RL = miles driven for the running loss test (see §86.134-96(c)(6)).

(2) For the supplemental two-diurnal test sequence, there is one final result to report: the sum of the adjusted total mass emissions for the diurnal and hot soak tests (M_DI + M_HS), described in §§86.133-96(p) and §86.138-96(k), respectively.

[58 FR 16043, Mar. 24, 1993, as amended at 59 FR 48510, Sept. 21, 1994; 60 FR 34348, June 30, 1995; 60 FR 43897, Aug. 23, 1995; 79 FR 23698, Apr. 28, 2014; 81 FR 73979, Oct. 25, 2016; 88 FR 4475, Jan. 24, 2023]

§86.144-94 Calculations; exhaust emissions.

The final reported test results shall be computed by use of the following formula:

(a) For light-duty vehicles and light duty trucks:

Where:

(1) Y_WM = Weighted mass emissions of each pollutant, i.e., THC, CO, THCE, NMHC, NMHCE, CH₄, NO_X, or CO₂, in grams per vehicle mile.

(2) Y_ct = Mass emissions as calculated from the “transient” phase of the cold start test, in grams per test phase.

(3) Y_ht = Mass emissions as calculated from the “transient” phase of the hot start test, in grams per test phase.

(4) Y_s = Mass emissions as calculated from the “stabilized” phase of the cold start test, in grams per test phase.

(5) D_ct = The measured driving distance from the “transient” phase of the cold start test, in miles.

(6) D_ht = The measured distance from the “transient” phase of the hot start test, in miles.

(7) D_s = The measured driving distance from the “stabilized” phase of the cold start test, in miles.

(b) The mass of each pollutant for each phase of both the cold start test and the hot start test is determined from the following:

(1) Total hydrocarbon mass:

HC_mass = V_mix × Density_HC × (HC_conc/1,000,000)

(2) Oxides of nitrogen mass:

NOx_mass = V_mix × Density_NO2 × K_H × (NOx_conc/1,000,000)

(3) Carbon monoxide mass:

CO_mass = V_mix × Density_CO × (CO_conc/1,000,000)

(4) Carbon dioxide mass:

CO_2mass = V_mix × Density_CO2 × (CO_2conc/100)

(5) Methanol mass:

CH₃OH_mass = V_mix × Density_CH3OH × (CH₃OH_conc/1,000,000)

(6) Formaldehyde mass:

HCHO_mass = V_mix × Density_HCHO × (HCHO_conc/1,000,000)

(7) Total hydrocarbon equivalent mass:

THCE_mass = HC_mass + 13.8756/32.042 × (CH₃OH_mass) + 13.8756/32.0262 × (HCHO_mass)

(8) Non-methane hydrocarbon mass:

NMHC_mass = V_mix × Density_NMHC × (NMHC_conc/1,000,000)

(9) Non-methane hydrocarbon equivalent mass:

NMHCE_mass = NMHC_mass + 13.8756/32.042 × (CH₃OH_mass) + 13.8756/30.0262 × (HCHO_mass)

(10) Methane mass:

CH_4mass = V_mix = Density_CH4 = (CH_4conc/1,000,00)

(11) Nitrous Oxide Mass:

V_mix × Density_N2O × (N₂O_conc/1,000,000)

(c) Meaning of symbols:

(1)(i) HC_mass = Total hydrocarbon emissions, in grams per test phase.

(ii) Density_HC = Density of total hydrocarbon.

(A) For gasoline-fuel, diesel-fuel and methanol fuel; Density_HC = 16.33 g/ft ³−carbon atom (0.5768 kg/m ³−carbon atom), assuming an average carbon to hydrogen ratio of 1:1.85, at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(B) For natural gas and liquefied petroleum gas-fuel; Density_HC = 1.1771 (12.011 + H/C (1.008)) g/ft ³−carbon atom (0.04157(12.011 + H/C (1.008))kg/m ³−carbon atom), where H/C is the hydrogen to carbon ratio of the hydrocarbon components of the test fuel, at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) HC_conc = Total hydrocarbon concentration of the dilute exhaust sample corrected for background, in ppm carbon equivalent, i.e., equivalent propane × 3.

(B) HC_conc = HC_e−HC_d(1−1/DF).

Where:

(iv)(A) HC_e = Total hydrocarbon concentration of the dilute exhaust sample or, for diesel-cycle (or methanol-fueled vehicles, if selected), average hydrocarbon concentration of the dilute exhaust sample as calculated from the integrated THC traces, in ppm carbon equivalent.

(B) HC_e = FID HC_e−(r)C_CH³OHe.

(v) FID HC_e = Concentration of total hydrocarbon plus methanol in dilute exhaust as measured by the FID, ppm carbon equivalent.

(vi) r = FID response to methanol.

(vii) C_CH³OHe = Concentration of methanol in dilute exhaust as determined from the dilute exhaust methanol sample in ppm carbon. For vehicles not fueled with methanol, C_CH³OHe equals zero.

(viii)(A) HC_d = Total hydrocarbon concentration of the dilution air as measured, in ppm carbon equivalent.

(B) HC_d = FID HC_d−(r)C_CH³OHd.

(ix) FID HC_d = Concentration of total hydrocarbon plus methanol in dilution air as measured by the FID, ppm carbon equivalent.

(x) C_CH³OHd = Concentration of methanol in dilution air as determined from dilution air methanol sample in ppm carbon. For vehicles not fueled with methanol, C_CH³OHd equals zero.

(2)(i) NOx_mass = Oxides of nitrogen emissions, in grams per test phase.

(ii) Density_NO2 = Density of oxides of nitrogen is 54.16 g/ft3 (1.913 kg/m ³) assuming they are in the form of nitrogen dioxide, at 68°F (20°C) and 760 mm Hg (101.3kPa) pressure.

(iii)(A) NOx_conc = Oxides of nitrogen concentration of the dilute exhaust sample corrected for background, in ppm.

(B) NOx_conc = NOx_e−NOx_d(1−(1/DF)).

Where:

(iv) NOx_e = Oxides of nitrogen concentration of the dilute exhaust sample as measured, in ppm.

(v) NOx_d = Oxides of nitrogen concentration of the dilution air as measured, in ppm.

(3)(i) CO_mass = Carbon monoxide emissions, in grams per test phase.

(ii) Density_CO = Density of carbon monoxide is 32.97 g/ft ³ (1.164 kg/m3), at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) CO_conc = Carbon monoxide concentration of the dilute exhaust sample corrected for background, water vapor, and CO₂ extraction, in ppm.

(B) CO_conc = CO_e − CO_d(1 − (1/DF)).

Where:

(iv)(A) CO_e = Carbon monoxide concentration of the dilute exhaust volume corrected for water vapor and carbon dioxide extraction, in ppm.

(B) CO_e = (1 − 0.01925CO_2e-0.000323R)CO_em for petroleum fuel with hydrogen to carbon ratio of 1.85:1.

(C) CO_e = [1−(0.01 + 0.005HCR) CO_2e−0.000323R]CO_em for methanol-fuel or natural gas-fuel or liquefied petroleum gas-fuel, where HCR is hydrogen-to-carbon ratio as measured for the fuel used.

(v) CO_em = Carbon monoxide concentration of the dilute exhaust sample as measured, in ppm.

(vi) CO_2e = Carbon dioxide concentration of the dilute exhaust sample, in percent.

(vii) R = Relative humidity of the dilution air, in percent (see §86.142(n)).

(viii)(A) CO_d = Carbon monoxide concentration of the dilution air corrected for water vapor extraction, in ppm.

(B) CO_d = (1-0.000323R)CO_dm.

Where:

(ix) CO_dm = Carbon monoxide concentration of the dilution air sample as measured, in ppm.

Note:

If a CO instrument which meets the criteria specified in §86.111 is used and the conditioning column has been deleted, CO_em must be substituted directly for CO_e and CO_dm must be substituted directly for CO_d.

(4)(i) CO_2mass = Carbon dioxide emissions, in grams per test phase.

(ii) Density CO₂ = Density of carbon dioxide is 51.81 g/ft ³ (1.830 kg/m ³), at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) CO_2conc = Carbon dioxide concentration of the dilute exhaust sample corrected for background, in percent.

(B) CO_2conc = CO_2e − CO_2d(1 − (1/DF)). Where:

(iv) CO_2d = Carbon dioxide concentration of the dilution air as measured, in percent.

(5)(i) CH₃OH_mass = Methanol emissions corrected for background, in grams per test phase.

(ii) Density_CH3OH = Density of methanol is 37.71 g/ft ³-carbon atom (1.332 kg/m ³-carbon atom), at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) CH₃OH_conc = Methanol concentration of the dilute exhaust corrected for background, ppm.

(B) CH₃OH_conc = C_CH3OHe − C_CH3OHd(1 − (1/DF)).

Where:

(iv)(A) C_CH3OHe = Methanol concentration in the dilute exhaust, ppm.

(B)

(v)(A) C_CH3OHd = Methanol concentration in the dilution air, ppm.

(B)

(vi) T_EM = Temperature of methanol sample withdrawn from dilute exhaust,°R.

(vii) T_DM = Temperature of methanol sample withdrawn from dilution air,°R.

(viii) P_B = Barometric pressure during test, mm Hg.

(ix) V_EM = Volume of methanol sample withdrawn from dilute exhaust, ft ³.

(x) V_DM = Volume of methanol sample withdrawn from dilution air, ft ³.

(xi) C_S = GC concentration of sample drawn from dilute exhaust, µg/ml.

(xii) C_D = GC concentration of sample drawn from dilution air, µg/ml.

(xiii) AVS = Volume of absorbing reagent (deionized water) in impinger through which methanol sample from dilute exhaust is drawn, ml.

(xiv) AVD = Volume of absorbing reagent (deionized water) in impinger through which methanol sample from dilution air is drawn, ml.

(xv) 1 = first impinger.

(xvi) 2 = second impinger.

(xvii) 1 = first impinger.

(xviii) 2 = second impinger.

(6)(i) HCHO_mass = Formaldehyde emissions corrected for background, in grams per test phase.

(ii) Density_HCHO = Density of formaldehyde is 35.36 g/ft ³- carbon atom (1.249 kg/m ³-carbon atom), at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) HCHO_conc = Formaldehyde concentration of the dilute exhaust corrected for background, in ppm.

(B) HCHO_conc = C_HCHOe − C_HCHOd (1 − (1/DF)).

Where:

(iv)(A) C_HCHOe = Formaldehyde concentration in dilute exhaust, in ppm.

(B)

(v)(A) C_HCHOd = Formaldehyde concentration in dilution air in ppm.

(B)

(vi) C_FDE = Concentration of DNPH derivative of formaldehyde from dilute exhaust sample in sampling solution, µg/ml.

(vii) V_AE = Volume of sampling solution for dilute exhaust formaldehyde sample, ml.

(viii)(A) Q = Ratio of molecular weights of formaldehyde to its DNPH derivative.

(B) Q = 0.1429.

(ix) T_EF = Temperature of formaldehyde sample withdrawn from dilute exhaust,°R.

(x) V_SE = Volume of formaldehyde sample withdrawn from dilute exhaust, ft ³.

(xi) P_B = Barometric pressure during test, mm Hg.

(xii) C_FDA = Concentration of DNPH derivative of formaldehyde from dilution air sample in sampling solution, µg/ml.

(xiii) V_AA = Volume of sampling solution for dilution air formaldehyde sample, ml.

(xiv) T_DF = Temperature of formaldehyde sample withdrawn from dilution air, °R.

(xv) V_SA = Volume of formaldehyde sample withdrawn from dilution air, ft ³.

(7)(i) DF = 13.4/[CO_2e + (HC_e + CO_e) 10⁻⁴] for petroleum-fueled vehicles.

(ii) For methanol-fueled vehicles, where fuel composition is C_XH_yO_z as measured, or calculated, for the fuel used:

(iii)

for natural gas-fueled or liquefied petroleum gas-fueled vehicles where fuel composition is C_x H_y as measured for the fuel used.

(iv)(A) K_H = Humidity correction factor.

(B) K_H = 1/[1−0.0047(H−75)].

(C) For SI units, K_H = 1 × [1-0.0329(H × 10.71)].

Where:

(v)(A) H = Absolute humidity in grains (grams) of water per pound (kilogram) of dry air.

(B) H=[(43.478)R_a × P_d]/[P_B−(P_d × R_a/100)].

(C) For SI units, H=[(6.211)R_a × P_d]/[P_B × (P_d × R_a/100)].

(vi) R_a = Relative humidity of the ambient air, percent.

(vii) P_d = Saturated vapor pressure, mm Hg (kPa) at the ambient dry bulb temperature.

(viii) P_B = Barometric pressure, mm Hg (kPa).

(ix)(A) V_mix = Total dilute exhaust volume in cubic feet per test phase corrected to standard conditions (528°R (293°K) and 760 mm Hg (101.3 kPa)).

(B) For PDP-CVS, V_mix is:

(C) For SI units,

Where:

(x) V_o = Volume of gas pumped by the positive displacement pump, in cubic feet (m ³) per revolution. This volume is dependent on the pressure differential across the positive displacement pump.

(xi) N = Number of revolutions of the positive displacement pump during the test phase while samples are being collected.

(xii) P_B = Barometric pressure, mm Hg (kPa).

(xiii) P₄ = Pressure depression below atmospheric measured at the inlet to the positive displacement pump, in mm Hg (kPa) (during an idle mode).

(xiv) T_p = Average temperature of dilute exhaust entering positive displacement pump during test,°R(°K).

(8)(i) NMHC_conc = HC_conc − (r_CH4 × CH_4conc).

(ii) Density_NMHC = The density of non-methane hydrocarbon.

(A) For gasoline-fuel and diesel-fuel; Density_NMHC = 16.33 g/ft ³-carbon atom (0.5768 kg/m ³-carbon atom), assuming an average carbon to hydrogen ratio of 1:1.85 at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(B) For natural gas and liquefied petroleum gas fuel; Density_NMHC = 1.1771(12.011 + H/C(1.008))g/ft ³-carbon atom (0.04157(12.011 + H/C(1.008))kg/m ³-carbon atom), where H/C is the hydrogen to carbon ratio of the non-methane hydrocarbon components of the test fuel, at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(iii)(A) CH_4conc = Methane concentration of the dilute exhaust sample corrected for background, in ppm carbon equivalent.

(B) CH_4conc = CH_4e − CH_4d(1 − 1/DF)

Where:

(iv) CH_4e = Methane exhaust bag concentration in ppm carbon equivalent.

(v) CH_4d = Methane concentration of the dilution air in ppm carbon equivalent.

(vi) rCH4 = HC FID response to methane as measured in §86.121(d).

(9)(i) CH_4mass = Methane emissions, in grams per test phase.

(ii) Density_CH4 = Density of methane is 18.89 g/ft ³-carbon atom (0.6672 kg/m ³-carbon atom), at 68°F (20°C) and 760 mm Hg (101.3 kPa) pressure.

(10)(i) N₂O_mass = Nitrous oxide emissions, in grams per test phase.

(ii) Density_N2O = Density of nitrous oxide is 51.81 g/ft ³ (1.83 kg/m ³), at 68°F (20°C) and 760 mm Hg (101.3kPa) pressure.

(iii)(A) N₂O_conc = Nitrous oxide concentration of the dilute exhaust sample corrected for background, in ppm.

(B) N₂O_conc = N₂O_e − N₂O_d(1 − (1/DF)).

Where:

N₂O_e = Nitrous oxide concentration of the dilute exhaust sample as measured, in ppm.

N₂O_d = Nitrous oxide concentration of the dilution air as measured, in ppm.

(d) For petroleum-fueled vehicles, example calculation of mass values of exhaust emissions using positive displacement pump:

(1) For the “transient” phase of the cold start test assume the following: V_o = 0.29344 ft ³rev; N = 10,485; R = 48.0 pct; R_a = 48.2 percent; P_B = 762 mm Hg; P_d = 22.225 mm Hg; P₄ = 70 mm Hg; T_p = 570°R; HC_e = 105.8 ppm, carbon equivalent; NOx_e = 11.2 ppm; CO_em = 306.6 ppm; CO_2e = 1.43 percent; CH_4e = 10.74 ppm; HC_d = 12.1 ppm; NOx_d = 0.8 ppm; CO_dm = 15.3 ppm; CO_2d = 0.032 percent; CH_4d = 2.20 ppm; D_ct = 3.598 miles.

Then:

(i) V_mix = (0.29344)(10,485)(762-70)(528)/(760)(570) = 2595.0 ft ³ per test phase.

(ii) H = (43.478)(48.2)(22.225)/762 − (22.225)(48.2/100) = 62 grains of water per pound of dry air.

(iii) K_H = 1/[1 − 0.0047(62-75)] = 0.9424.

(iv) CO_e = [1-0.01925(1.43) − 0.000323(48)](306.6) = 293.4 ppm.

(v) CO_d = [1 − 0.000323(48)](15.3) = 15.1 ppm.

(vi) DF = 13.4/[1.43 + 10⁻⁴(105.8 + 293.4)] = 9.116.

(vii) HC_conc = 105.8-12.1(1 − 1/9.116) = 95.03 ppm.

(viii) HC_mass = (2595)(16.33)(95.03/1,000,000) = 4.027 grams per test phase.

(ix) NOx_conc = 11.2 − 0.8(1 − 1/9.116) = 10.49 ppm.

(x) NOx_mass = (2595)(54.16)(10.49/1,000,000)(0.9424) = 1.389 grams per test phase.

(xi) CO_conc = 293.4 − 15.1(1 − 1/9.116) = 280.0 ppm.

(xii) CO_mass = (2595)(32.97)(280/1,000,000) = 23.96 grams per test phase.

(xiii) CO_2conc = 1.43 − 0.032(1 − 1/9.116) = 1.402 percent.

(xiv) CO_2mass = (2595.0)(51.85)(1.402/100) = 1886 grams per test phase.

(xv) CH_4conc = 10.74 − 2.2 (1 − 1/9.116) = 8.78 ppm.

(xvi) NMHC_conc = 95.03 − 8.78 = 86.25 ppm.

(xvii) NMHC_mass = (2595)(16.33)(86.25)/1,000,000 = 3.655 grams per test phase.

(2) For the stabilized portion of the cold start test assume that similar calculations resulted in the following:

(i) HC_mass = 0.62 gram per test phase.

(ii) NOx_mass = 1.27 grams per test phase.

(iii) CO_mass = 5.98 grams per test phase.

(iv) CO_2mass = 2346 grams per test phase.

(v) D_s = 3.902 miles.

(vi) NMHC_mass = 0.50 gram per test phase.

(3) For the “transient” portion of the hot start test assume that similar calculations resulted in the following:

(i) HC_mass = 0.51 gram per test phase.

(ii) NOx_mass = 1.38 grams per test phase.

(iii) CO_mass = 5.01 grams per test phase.

(iv) CO_2mass = 1758 grams per test phase.

(v) D_ht = 3.598 miles.

(vi) NMHC_mass = 0.44 grams per test phase.

(4) Weighted mass emission results:

(i) HC_wm = 0.43[(4.027 + 0.62)/(3.598 + 3.902)] + 0.57[(0.51 + 0.62)/(3.598 + 3.902)] = 0.352 gram per vehicle mile.

(ii) NOx_wm = 0.43[(1.389 + 1.27)/(3.598 + 3.902)] + 0.57[(1.38 + 1.27)/(3.598 + 3.902)] = 0.354 gram per vehicle mile.

(iii) CO_wm = 0.43[(23.96 + 5.98)/(3.598 + 3.902)] + 0.57[(5.01 + 5.98)/(3.598 + 3.902)] = 2.55 grams per vehicle mile.

(iv) CO_2wm = 0.43[(1886 + 2346)/(3.598 + 3.902) + 0.57[(1758 + 2346)/(3.598 + 3.902)] = 555 gram per vehicle mile.

(v) NMHC_wm = 0.43[(3.655 + 0.50)/(3.598 + 3.902)] + 0.57[(0.44 + 0.50)/(3.598 + 3.902)] = 0.310 gram per vehicle mile.

(e) For methanol-fueled vehicles with measured fuel composition of CH_3.487 O_0.763, example calculation of exhaust emissions using positive displacement pump:

(1) For the “transient” phase of the cold start test assume the following: V₀ = 0.29344 ft ³ rev; N = 25,801; R = 37.5 pct; Ra = 37.5 percent; P_B = 725.42 mm Hg; P_d = 22.02 mm Hg; P₄ = 70 mm Hg; T_p 570 deg.R; FID HC_e = 14.65 ppm, carbon equivalent; r = 0.788; T_EM = 527.67 deg.R; V_EM = 0.2818 ft ³; C_S1 = 7.101; AV_S1 = 15.0 ml; C_S2 = 0.256; AV_S2 = 15.0 ml; T_DM = 527.67 deg.R; V_DM = 1.1389 ft ³; C_D1 = 0.439; AV_D1 = 15.0 ml; C_D2 = 0.0; AV_D2 = 15.0 ml; C_FDE = 8.970 µg/ml; V_AE = 5.0 ml; Q = 0.1429; T_EF = 527.67 deg.R; V_SE = 0.2857 ft ³; C_FDA = 0.39 µg/ml; V_AA = 5.0 ml; T_DF = 527.67 deg.R; V_SA = 1.1043 ft ³; NO_X. = 5.273 ppm; CO_em = 98.8 ppm; CO_2e = 0.469 pct; CH_4e = 2.825 ppm; FID HC_d = 2.771 ppm; NO_X. = 0.146 ppm; CO_dm = 1.195 ppm; CO_2d = 0.039 percent; CH_4d = 2.019 ppm; Dct = 3.583 miles.

Then:

(i) V_mix = (0.29344)(25,801)(725.42-70)(528)/(760)(570) = 6048.1.0 ft ³ per test phase.

(ii) H = (43.478)(37.5)(22.02)/[725.42-(22.02 × 37.5/100)] = 50 grains of water per pound of dry air.

(iii) K_H = 1/[1−0.0047(50−75)] = 0.8951.

(iv) CO_e = [1-(0.01 + 0.005 × 3.487) × 0.469)−0.000323(37.5)) × 98.8 = 96.332 ppm.

(v) CO_d = (1−0.000323(37.5)) × 1.195 = 1.181 ppm.

(vi) C_CH3OHe = (3.813 × 10⁻²)(527.67)[(7.101)(15.0) + (0.256)(15.0)]/(725.42)(0.2818) = 10.86 ppm.

(vii) HCe = 14.65−(0.788)(10.86) = 6.092.

(viii) DF = 100(1/[1 + (3.487/2) + 3.76(1 + (3.487/4) − (0.763/2))])/0.469 + (6.092 + 96.332 + 10.86 + 0.664)(10⁻⁴) = 24.939.

(ix) C_CH3OHd = (3.813 × 10⁻²)(527.67)[(0.439)(15.0) + (0.0)(15.0)]/(725.42)(1.1389) = 0.16 ppm.

(x) CH₃OH_conc = 10.86−0.16(1-1/24.939) = 10.71 ppm.

(xi) CH₃OH_mass = 6048.1 × 37.71 × (10.71/1,000,000) = 2.44 grams per test phase.

(xii) HC_conc = [14.65 − (0.788)(10.86)] − [2.771 − (0.788)(0.16)] (1-1/24.94) = 3.553 ppm.

(xiii) HC_mass = (6048.1)(16.33)(3.553/1,000,000) = 0.35 grams per test phase.

(xiv) C_HCHOe = 4.069 × 10⁻²(8.970)(5.0)(0.1429)(527.67)/(0.2857)(725.42) = 0.664 ppm.

(xv) C_HCHOd = 4.069 × 10⁻²(0.39)(5.0)(0.1429)(527.67)/(1.1043)(725.42) = 0.0075 ppm.

(xvi) HCHO_conc = 0.664-0.0075(1-1/24.939) = 0.6568 ppm.

(xvii) HCHO_mass = (6048.1)(35.36)(0.6568/1,000,000) = 0.1405 grams per test phase.

(xviii) THCE = 0.35 + (13.8756/32.042)(2.44) + (13.8756/ 30.0262)(0.1405) = 1.47 grams per test phase.

(xix) NO_Xconc = 5.273−(0.146)(1-1/24.939) = 5.13 ppm.

(xx) NO_Xmass = (6048.1)(54.16)(5.13/1,000,000)(0.8951) = 1.505 grams per test phase.

(xxi) CO_conc = 96.332−1.181(1-1/24.939) = 95.2 ppm.

(xxii) CO_mass = (6048.1)(32.97)(95.2/1,000,000) = 18.98 grams per test phase.

(xxiii) CO2_conc = 0.469-0.039(1-1/24.939) = 0.432 percent.

(xxiv) CO2_mass = (6048.1)(51.85)(0.432/100) = 1353 grams.

(xxv) CH4_conc = 2.825-2.019(1-1/24.939) = 0.89 ppm.

(xxvi) NMHC_conc = 3.553 ppm−0.89 ppm = 2.67 ppm.

(xxvii) NMHC_mass = (6048.1)(16.33)(2.67/1,000,000) = 0.263 grams per test phase.

(xxviii) NMHCE_mass = 0.263 + (13.8756/32.042)(2.44) + (13.8756/ 30.0262)(0.1405) = 1.39 grams per test phase.

(2) For the stabilized portion of the cold start test assume that similar calculations resulted in the following:

(i) THCE = 0.143 grams per test phase.

(ii) NO_Xmass = 0.979 grams per test phase.

(iii) CO_mass = 0.365 grams per test phase.

(iv) CO_2mass = 1467 grams per test phase.

(v) D_s = 3.854 miles.

(vi) NMHCE = 0.113 grams per test phase.

(3) For the “transient” portion of the hot start test assume that similar calculations resulted in the following:

(i) THCE = 0.488 grams as carbon equivalent per test phase.

(ii) NO_Xmass = 1.505 grams per test phase.

(iii) CO_mass = 3.696 grams per test phase.

(iv) CO_2mass = 1179 grams per test phase.

(v) D_ht = 3.577 miles.

(vi) NMHCE = 0.426 grams per test phase.

(4) Weighted emission results:

(i) THCE_wm = (0.43) × (1.473 + 0.143)/(3.583 + 3.854) + (0.57) × (0.488 + 0.143)/(3.577 + 3.854) = 0.142 grams as carbon equivalent per mile.

(ii) NOx_wm = (0.43) × (1.505 + 0.979)/(3.583 + 3.854) + (0.57) × (1.505 + 0.979)/3.577 + 3.854) = 0.344 grams per mile.

(iii) CO_wm = (0.43) × (18.983 + 0.365)/(3.583 = 3.854) + (0.57) × (3.696 + 0.365)/(3.577 + 3.854) = 1.43 grams per mile.

(iv) CO2_wm = (0.43) × (1353 + 1467)/(3.583 + 3.854) + (0.57) × (1179 + 1467)/(3.577 + 3.854) = 366 grams per mile.

(v) NMHCE_wm = (0.43) × (1.386 + 0.113)/(3.583 + 3.854) + (0.57) × (0.426 = 0.113)/(3.577 + 3.854) = 0.128 grams per mile.

[56 FR 25777, June 5, 1991, as amended at 59 FR 39649, Aug. 3, 1994; 59 FR 48511, Sept. 21, 1994; 60 FR 34349, June 30, 1995; 62 FR 47122, Sept. 5, 1997; 70 FR 40434, July 13, 2005; 75 FR 22980, Apr. 30, 2010; 76 FR 57376, Sept. 15, 2011]

§86.145-82 Calculations; particulate emissions.

(a) The final reported test results for the mass particulate (M_p) in grams/mile shall be computed as follows.

M_p = 0.43(M_p1 + M_p2)/(D_ct + D_s) + 0.57(M_p3 + M_p2)/(D_ht = D_s)

where:

(1) M_p1 = Mass of particulate determined from the “transient” phase of the cold start test, in grams per test phase. (See §86.110-82(c)(1) for determination.)

(2) M_p2 = Mass of particulate determined from the “stabilized” phase of the cold start test, in grams per test phase. (See §86.110-82(c)(1) for determination.)

(3) M_p3 = Mass of particulate determined from the “transient” phase of the hot start test, in grams per test phase. (See §86.110-82(c)(1) for determination).

(4) D_ct = The measured driving distance from the “transient” phase of the cold start test, in miles.

(5) D_s = The measured driving distance from the “stabilized” phase of the cold start test, in miles.

(6) D_ht = The measured driving distance from the “transient” phase of the hot start test, in miles.

(b) The mass of particulate for each phase of testing is determined as follows:

where:

(1) j = 1, 2 or 3 depending on which phase the mass of particulate is being determined for (i.e., the “transient” phase of the cold start test, the “stabilized” phase of the cold start test, or the “transient” phase of the hot start test).

(2) V_mix = Total dilute exhaust volume in cubic meters per test, corrected to standard conditions 528°R (293K) and 29.92 in Hg (101.3 kPa). V_mix is further defined in §86.144.

(3) P_e = mass of particulate per test on the exhaust filter(s), grams.

(4) P_b = mass of particulate on the “background” filter, grams.

(i) The background particulate level, P_b, inside the dilution air filter box at EPA is very low. P_b will be assumed = 0, and background particulate samples will not be taken with each exhaust sample. It is recommended that background particulate checks be made periodically to verify the low level.

(ii) Any manufacturer may make the same assumption without prior EPA approval.

(iii) If P_b is assumed = 0, then no background correction is made. The equation for particulate mass emissions then reduces to:

(6) V_ep = total volume of sample pulled through the filter, cubic feet at standard conditions.

where:

(i) V_ap = corrected (according to procedure specified in §85.120) dilute exhaust sample volume, cubic feet.

(ii) P_bar = barometric pressure, in Hg.

(iii) P_ip = pressure elevation above ambient measured at the inlet to the dilute exhaust sample gas meter or flow instrument, in Hg. (For most gas meters with unrestricted discharge P_ip is negligible and can be assumed = 0.)

(iv) T_ip = average temperature of the dilute exhaust sample at the inlet to the gas meter or flow instrument,°R.

(7) V_bp = total volume of the background sample, cubic feet at standard conditions. (V_bp is not required if P_b is assumed = 0.) It is calculated using the following formula:

where:

(i) V_ab = corrected (according to procedure specified in §85.120 background sample volume, cubic feet.

(ii) P_bar = barometric pressure, in. Hg.

(iii) P_ib = pressure elevation above ambient measured at the inlet to the background gas meter or flow instrument, in Hg. (For most gas meters with unrestricted discharge P_ib is negligible and can be assumed = 0.)

(iv) T_ib = average temperature of the background sample at the inlet to the gas meter or flow instrument,°R.

(8) DF = dilution factor. (DF is not required if P_b is assumed = 0.)

[45 FR 14523, Mar. 5, 1980, as amended at 46 FR 50494, Oct. 13, 1981, and 47 FR 49807, Nov. 2, 1982]

§86.146-96 Fuel dispensing spitback procedure.

(a) The vehicle is fueled at a rate of 10 gal/min to test for fuel spitback emissions. All liquid fuel spitback emissions that occur during the test are collected in a bag made of a material impermeable to hydrocarbons or methanol. The bag shall be designed and used so that liquid fuel does not spit back onto the vehicle body, adjacent floor, etc., and it must not impede the free flow of displaced gasoline vapor from the orifice of the filler pipe. The bag must be designed to permit passage of the dispensing nozzle through the bag. If the bag has been used for previous testing, sufficient time shall be allowed for the bag to dry out. The dispensing nozzle shall be a commercial model, not equipped with vapor recovery hardware.

(b) Ambient temperature levels encountered by the test vehicle shall be not less than 68°F nor more than 86°F. The temperatures monitored during testing must be representative of those experienced by the test vehicle. The vehicle shall be approximately level during all phases of the test sequence to prevent abnormal fuel distribution.

(c) Measure and record the mass of the bag to be used for collecting spitback emissions to the nearest 0.01 gram.

(d) Drain the fuel tank(s) and fill with test fuel, as specified in §86.113, to 10 percent of the reported nominal fuel tank capacity. The fuel cap(s) shall be installed immediately after refueling.

(e) The vehicle shall be soaked at 80±6°F (27±3°C) for a minimum of six hours, then placed, either by being driven or pushed, on a dynamometer and operated through one Urban Dynamometer Driving Schedule (specified in §86.115 and appendix I of this part). The test vehicle may not be used to set dynamometer horsepower.

(f) Following the preconditioning drive, the vehicle shall be moved or driven at minimum throttle to the refueling area.

(g) All areas in proximity to the vehicle fuel fill orifice and the dispenser nozzle itself shall be completely dry of liquid fuel.

(h) The fuel filler neck shall be snugly fitted with the vented bag to capture any fuel emissions. The fuel nozzle shall be inserted through the bag into the filler neck of the test vehicle to its maximum penetration. The plane of the nozzle's handle shall be perpendicular to the floor of the laboratory.

(i) The fueling procedure consists of dispensing fuel through a nozzle, interrupted by a series of automatic shutoffs. A minimum of 3 seconds shall elapse between any automatic shutoff and subsequent resumption of dispensing. Dispensing may not be manually terminated, unless the test vehicle has already clearly failed the test. The vehicle shall be fueled according to the following procedure:

(1) The fueling operation shall be started within 4 minutes after the vehicle is turned off and within 8 minutes after completion of the preconditioning drive. The average temperature of the dispensed fuel shall be 65 ±5°F (18 ±3°C).

(2) The fuel shall be dispensed at a rate of 9.8±0.3 gallons/minute (37.1±1.1 L/min) until the automatic shutoff is activated.

(3) If the automatic shutoff is activated before the nozzle has dispensed an amount of fuel equal to 70 percent of the tank's nominal capacity, the dispensing may be resumed at a reduced rate. Repeat as necessary until the nozzle has dispensed an amount of fuel equal to at least 70 percent of the tank's nominal capacity.

(4) Once the automatic shutoff is activated after the nozzle has dispensed an amount of fuel equal to 70 percent of the tank's nominal capacity, the fuel shall be dispensed at a rate of 5 ±1 gallons/minute (19 ±4 ℓ/min) for all subsequent dispensing. Dispensing shall be restarted two additional times.

(5) If the nozzle has dispensed an amount of fuel less than 85 percent of the tank's nominal capacity after the two additional dispensing restarts, dispensing shall be resumed, and shall continue through as many automatic shutoffs as necessary to achieve this level. This completes the fueling procedure.

(j) Withdraw the nozzle from the vehicle and the bag, holding the tip of the nozzle upward to avoid any dripping into the bag.

(k) Within 1 minute after completion of the fueling event, the bag shall be folded to minimize the vapor volume inside the bag. The bag shall be folded as quickly as possible to prevent evaporation of collected emissions.

(l) Within 5 minutes after completion of the fueling event, the mass of the bag and its contents shall be measured and recorded (consistent with paragraph (c) of this section). The bag shall be weighed as quickly as possible to prevent evaporation of collected emissions.

[58 FR 16045, Mar. 24, 1993, as amended at 60 FR 43898, Aug. 23, 1995]

§86.150-98 Refueling test procedure; overview.

(a) The refueling emissions test procedure described in this and subsequent sections is used to determine the conformity of vehicles with the refueling emissions standards set forth in subpart A of this part for light-duty vehicles and light-duty trucks. The refueling emissions test procedure may be performed as an individual test or in combination with the evaporative and exhaust emissions test sequences of §86.130-96.

(b) The refueling emissions test is designed to measure hydrocarbon emissions resulting from the generation or displacement of fuel tank vapor during vehicle refueling. The refueling emissions shall be measured by the enclosure technique.

(c) All emission control systems installed on or incorporated in a new motor vehicle shall be functioning during all procedures in this subpart except:

(1) In cases of component malfunction or failure; and

(2) during certain specified fuel drain and fill operations, at which times the refueling emission control canister is disconnected. Maintenance to correct component malfunction or failure shall be authorized in accordance with §86.098-25.

(d) For liquefied petroleum gas-fueled vehicles only. Refueling test procedures for light-duty vehicles and light-duty trucks operated on liquefied petroleum gas are described in §86.157.

[59 FR 16296, Apr. 6, 1994, as amended at 59 FR 48511, Sept. 21, 1994]

§86.151-98 General requirements; refueling test.

(a) The refueling emissions procedure, shown in Figure B98-12, starts with the stabilizing of the vehicle and the loading of the refueling emissions canister(s) to breakthrough, and continues with the vehicle drive for purging of the canister, followed by the refueling emissions measurement. The test is conducted following §§86.152-98 through 86.154-98 in order.

(b) Ambient temperature levels encountered by the test vehicle throughout the test sequence shall not be less than 68°F (20°C) nor more than 86°F (30°C).

(c) The vehicle shall be approximately level during all phases of the test sequence to prevent abnormal fuel distribution.

[59 FR 16296, Apr. 6, 1994]

§86.152-98 Vehicle preparation; refueling test.

(a) Provide additional fittings and adapters, as required, to accommodate a fuel drain at the lowest point possible in the tank(s) as installed on the vehicle. The canister shall not be removed from the vehicle, unless access to the canister in its normal location is so restricted that purging and loading can only reasonably be accomplished by removing the canister from the vehicle. Special care shall be taken during this step to avoid damage to the components and the integrity of the fuel system. A replacement canister may be temporarily installed during the soak period while the canister from the test vehicle is preconditioned.

(b) Optionally, provide valving or other means to allow the venting of the refueling vapor line to the atmosphere rather than to the refueling emissions canister(s) when allowed by this test procedure.

(c) For preconditioning that involves loading the vapor collection canister(s) with butane, provide valving or other means as necessary to allow loading of the canister(s).

[59 FR 16298, Apr. 6, 1994, as amended at 60 FR 43898, Aug. 23, 1995; 70 FR 72927, Dec. 8, 2006]

§86.153-98 Vehicle and canister preconditioning; refueling test.

(a) Vehicle and canister preconditioning. Vehicles and vapor storage canisters shall be preconditioned in accordance with the preconditioning procedures for the supplemental two-diurnal evaporative emissions test specified in §86.132-96 (a) through (j). For vehicles equipped with non-integrated refueling emission control systems, the canister must be loaded using the method involving butane loading to breakthrough (see §86.132-96(j)(1)).

(b) Seal test. The Administrator may choose to omit certain canister load and purge steps, and replace them with a bench purge of the refueling canister(s), in order to verify the adequacy of refueling emission control system seals. Failure of this seal test shall constitute a failure of the refueling emission control test. For integrated systems, this bench purge may be performed after the exhaust testing in order to obtain exhaust emission test results. Non-integrated system seal testing shall be performed using paragraph (b)(1) of this section.

(1) Without the exhaust emission test. The Administrator may conduct the canister preconditioning by purging the canister(s) with at least 1200 canister bed volumes of ambient air (with humidity controlled to 50±25 grains of water vapor per pound of dry air) maintained at a nominal flow rate of 0.8 cfm directly following the preconditioning drive described in §86.132-96 (c) through (e). In this case, the canister loading procedures and the vehicle driving procedures described in §86.132-96 (f) through (j) and in paragraphs (c) through (d) of this section shall be omitted, and the 10 minute and 60 minute time requirements of paragraph (e) of this section shall apply to time after completion of the bench purge. In the case of multiple refueling canisters, each canister shall be purged separately.

(2) With the exhaust emission test. The Administrator may conduct the canister preconditioning by purging the canister(s) directly after the exhaust test (see paragraph (c)(1) of this section). The canister shall be purged with at least 1200 canister bed volumes of ambient air (with humidity controlled to 50±25 grains of water vapor per pound of dry air) maintained at a nominal flow rate of 0.8 cfm. In this case, the vehicle driving procedures described in paragraphs (c)(2) through (d) of this section shall be omitted, and the 10 minute and 60 minute time requirements of paragraph (e) of this section shall apply to time after completion of the bench purge. In the case of multiple refueling canisters, each canister shall be purged separately.

(3) Manufacturers may use the procedures described in this paragraph (b) to demonstrate compliance with the seal test for vehicles with fuel tanks exceeding 35 gallons nominal fuel tank capacity, and for any incomplete vehicles.

(c) Canister purging; integrated systems. (1) Vehicles to be tested for exhaust emissions only shall be processed according to §§86.135-94 through 86.137-96. Vehicles to be tested for refueling emissions shall be processed in accordance with the procedures in §§86.135-94 through 86.137-96, followed by the procedures outlined in paragraph (c)(2) of this section.

(2) To provide additional opportunity for canister purge, conduct additional driving on a dynamometer, within one hour of completion of the hot start exhaust test, by operating the test vehicle through one UDDS, a 2 minute idle, two NYCCs, another 2 minute idle, another UDDS, then another 2 minute idle (see §86.115-78 and appendix I of this part). Fifteen seconds after the engine starts, place the transmission in gear. Twenty seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule. The transmission shall be operated according to the specifications of §86.128-79 during the driving cycles. The vehicle's air conditioner (if so equipped) shall be turned off. Ambient temperature shall be controlled as specified in §86.151-98. It is not necessary to monitor and/or control in-tank fuel temperatures.

(i) The fixed-speed fan specified in §86.135-94(b) may be used for engine cooling. If a fixed-speed fan is used, the vehicle's hood shall be opened.

(ii) Alternatively, the roadspeed-modulated fan specified in §86.107-96(d)(1) may be used for engine cooling. If a road-speed modulated fan is used, the vehicle's hood shall be closed.

(d) Canister purging: non-integrated systems. Within one hour of completion of canister loading to breakthrough, the fuel tank(s) shall be further filled to 95 percent of nominal tank capacity determined to the nearest one-tenth of a U.S. gallon (0.38 liter) with the fuel specified in §86.113-94. During this fueling operation, the refueling emissions canister(s) shall be disconnected, unless the manufacturer specifies that the canister(s) should not be disconnected. Following completion of refueling, the refueling emissions canister(s) shall be reconnected, if the canister was disconnected during refueling. Special care shall be taken during this step to avoid damage to the components and the integrity of the fuel system. Vehicle driving to purge the refueling canister(s) shall be performed using either the chassis dynamometer procedure or the test track procedure, as described in paragraphs (d)(1) and (d)(2) of this section. The Administrator may choose to shorten the vehicle driving for a partial refueling test as described in paragraph (d)(3) of this section. For vehicles equipped with dual fuel tanks, the required volume of fuel shall be driven out of one tank, the second tank shall be selected as the fuel source, and the required volume of fuel shall be driven out of the second tank.

(1) Chassis dynamometer procedure. (i) Vehicle driving on a chassis dynamometer shall consist of repeated drives with the UDDS until 85 percent of fuel tank capacity has been consumed. Driving in testing performed by manufacturers may be terminated before 85 percent of the fuel tank capacity has been consumed, provided that driving is not terminated partway through a UDDS cycle. Driving in testing performed by the Administrator may be terminated after the same number of UDDS cycles as driven in the manufacturer's certification testing.

(ii) Except with the advance approval of the Administrator, the number of UDDSs required to consume 85 percent of tank fuel capacity (total capacity of both tanks when the vehicle is equipped with dual fuel tanks) shall be determined from the fuel economy on the UDDS applicable to the test vehicle and from the number of gallons to the nearest 0.1 gallon (0.38 liter) that constitutes 85 percent of tank volume. If this “fuel consumed point” occurs partway through a UDDS cycle, the cycle shall be completed in its entirety.

(iii) For vehicles equipped with dual fuel tanks, fuel switching from the first tank to the second tank shall occur at the 10 percent volume of the first tank regardless of the point in the UDDS cycle at which this occurs.

(iv) If necessary to accommodate work schedules, the engine may be turned off and the vehicle parked on the dynamometer. The vehicle may be parked off of the dynamometer to facilitate maintenance or repairs if required.

(v) During the driving on the dynamometer, a cooling fan(s) shall be positioned as described in §86.135-94(b).

(2) Test track procedure. (i) Vehicle driving on a test track shall consist of repeated drives with the UDDS until 85 percent of fuel tank capacity has been consumed. Driving performed by manufacturers may be terminated before 85 percent of the fuel tank capacity has been consumed, provided that driving is not terminated partway through a UDDS cycle. Driving performed by the Administrator may be terminated after the same number of UDDS cycles as driven in the manufacturer's certification testing.

(ii) If the distance from the emission laboratory to the test track is less than 5 miles (8.05 km) the vehicle may be driven to the test track at a speed not to exceed 25 mph. If the distance is greater than 5 miles (8.05 km) the vehicle shall be moved to the test track with the engine off.

(iii) Except with the advance approval of the Administrator, the number of UDDSs required to consume 85 percent of tank fuel capacity (total capacity of both tanks when the vehicle is equipped with dual fuel tanks) shall be determined from the fuel economy on the UDDS applicable to the test vehicle and from the number of gallons to the nearest 0.1 gallon (0.38 liter) that constitutes 85 percent of tank volume. If this “fuel consumed point” occurs partway through a UDDS cycle, the cycle shall be completed in its entirety.

(iv) The vehicle shall be driven at a speed not to exceed 25 mph from the test track to the laboratory provided the distance from the test track to the laboratory does not exceed 5 miles (8.05 km). If the distance from the test track to the emission laboratory is greater than 5 miles (8.05 km) the vehicle shall be moved from the test track with the engine off.

(v) For vehicles equipped with dual fuel tanks, fuel switching from the first tank to the second tank shall occur at the 10 percent volume of the first tank regardless of the point in the UDDS cycle at which this occurs.

(vi) If necessary to accommodate work schedules, the engine may be turned off and the vehicle parked on the test track. The vehicle may be parked off of the test track to facilitate maintenance or repairs if required. If the vehicle is moved from the test track, it shall be returned to the track with the engine off when mileage accumulation is to be resumed.

(3) Drive schedule for partial refueling test. The Administrator may conduct a partial refueling test involving a shortening of the drive procedures described in paragraphs (d) (1) and (2) of this section and a modified soak and refueling procedure as described in paragraph (e) of this section and §86.154-98(e)(7)(i). The drive shall be performed as described in paragraph (d) (1) or (2) of this section except that the drive shall be terminated when at least 10 percent but no more than 85 percent of the fuel tank nominal capacity has been consumed and not partway through a UDDS cycle. The amount of fuel consumed in the drive shall be determined by multiplying the number of UDDSs driven by the mileage accumulated per UDDS and dividing by the fuel economy for the UDDS applicable to the test vehicle.

(e) Vehicle cool down- (1) Partial refueling test. If the Administrator is conducting the non-integrated system partial refueling test, after the driving procedure specified in paragraph (d)(3) of this section, the vehicle shall be parked (without starting the engine) and soaked at 80±3°F (27±1.7°C) for a minimum of 1 hour and a maximum of 6 hours.

(2) For all other refueling emission tests. Within 10 minutes of completion of refueling emissions canister stabilization (see paragraph (c) or (d) of this section), the refueling emissions canister(s) shall be disconnected, unless the manufacturer specifies that the refueling canister(s) should not be disconnected. Within 60 minutes of completion of refueling emissions canister stabilization (see paragraph (c) or (d) of this section), the vehicle fuel tank(s) shall be drained, the fuel tank(s) fueled to 10 percent of nominal tank capacity determined to the nearest one-tenth of a U.S. gallon (0.38 liter) with the specified fuel, and the vehicle parked (without starting the engine) and soaked at 80±3°F (27±1.7°C) for a minimum of 6 hours and a maximum of 24 hours.

[59 FR 16298, Apr. 6, 1994, as amended at 60 FR 43898, Aug. 23, 1995; 70 FR 72927, Dec. 8, 2005; 79 FR 23698, Apr. 28, 2014]

§86.154-98 Measurement procedure; refueling test.

(a) The refueling test measurement procedure described in this section immediately follows the vehicle and canister preconditioning described in §86.153-98.

(b) The refueling emission enclosure shall be purged for several minutes immediately prior to the test. Warning: If at any time the concentration of hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 ppm C, the enclosure should be immediately purged. This concentration provides a 4:1 safety factor against the lean flammability limit.

(c)(1) The FID (or HFID) hydrocarbon analyzer, and additional analyzer, if needed, shall be zeroed and spanned immediately prior to the test.

(2) For methanol-fueled vehicles only, impingers charged with known volumes of pure deionized water shall be placed in the methanol sampling system.

(d) If not already on, the enclosure mixing fan and the spilled fuel mixing blower shall be turned on at this time.

(e) The refueling emission measurement portion of the refueling test shall be performed as follows:

(1) The line from the fuel tank(s) to the refueling emissions canister(s) shall be connected.

(2) The test vehicle, with the engine shut off, shall be moved into the enclosure. The test vehicle windows and luggage compartment shall be opened if not already open.

(3) An electrical ground shall be attached to the vehicle. The vehicle fuel filler cap shall be removed and the enclosure door shall be closed and sealed within two minutes of cap removal. The FID (or HFID) trace shall be allowed to stabilize.

(4) The dispensed fuel temperature recording system shall be started.

(5)(i) Within 10 minutes of closing and sealing the doors, analyze enclosure atmosphere for hydrocarbons and record. This is the initial (time = 0 minutes) hydrocarbon concentration, C_HCi, required in §86.143-96.

(ii) For methanol-fueled vehicles only, measure the initial concentration of methanol as described in §86.133-96(i)(6).

(6) Within one minute of obtaining the initial FID (or HFID) reading, and methanol reading if applicable, the fuel nozzle shall be inserted into the filler neck of the test vehicle, to its maximum penetration, and the refueling operation shall be started. The plane of the nozzle's handle shall be approximately perpendicular to the floor of the laboratory. The fuel shall be dispensed at a temperature of 67±1.5°F (19.4±0.8°C) and at a dispensing rate of 9.8±0.3 gal/min (37.1±1.1 liter/min). In testing conducted by the Administrator, a lower dispensing rate (no lower than 4.0 gal/min (15.1 liter/min)) may be used.

(7)(i) Partial refueling test. If the Administrator conducts the non-integrated system partial refueling test, the fuel flow shall continue until the amount of fuel pumped is equal to the fuel consumed during the driving, as determined in accordance with §86.153-98(d)(3). The final volume of fuel dispensed must be within one-tenth of a U.S. gallon (0.38 liter) of the targeted amount. If automatic nozzle shut-off occurs prior to this point, the nozzle shall be reactivated within 15 seconds and fuel dispensing continued as needed. A minimum of 3 seconds shall elapse between any automatic shutoff and subsequent resumption of dispensing.

(ii) For all other refueling tests. The fuel flow shall continue until the refueling nozzle automatic shut-off is activated. The amount of fuel dispensed must be at least 85 percent of nominal fuel tank volume, determined to the nearest one-tenth of a U.S. gallon (0.38 liter). If automatic nozzle shut-off occurs prior to this point, the nozzle shall be reactivated within 15 seconds and fuel dispensing continued as needed. A minimum of 3 seconds shall elapse between any automatic shutoff and subsequent resumption of dispensing. Dispensing may not be manually terminated, unless the test vehicle has already clearly failed the test.

(8)(i) The final reading of the evaporative enclosure FID analyzer shall be taken 60±5 seconds following the final shut-off of fuel flow. This is the final hydrocarbon concentration, C_HCf, required in §86.143-96. The elapsed time, in minutes, between the initial and final FID (or HFID) readings shall be recorded.

(ii) For methanol-fueled vehicles only. Measure the final concentration of methanol as described in §86.133-96(m)(2).

(9) For vehicles equipped with more than one fuel tank, use good engineering judgment to apply the procedures described in this section for each fuel tank.

[59 FR 16299, Apr. 6, 1994, as amended at 60 FR 43898, Aug. 23, 1995; 88 FR 4475, Jan. 24, 2023]

§86.155-98 Records required; refueling test.

The following information shall be recorded with respect to each test:

(a) Test number.

(b) System or device tested (brief description).

(c) Date and time of day.

(d) Instrument operated.

(e) Operator.

(f) Vehicle: ID number, manufacturer, model year, engine family, evaporative/refueling emission family, refueling emission control system, refueling emissions canister continuous drive purge miles and number of UDDSs driven for non-integrated systems, fuel system (including fuel tank(s) capacity and location), basic engine description (including displacement, number of cylinders, turbocharger (if used), and catalyst usage), engine code, and odometer reading.

(g) All pertinent instrument information including nozzle and fuel delivery system description. As an alternative, a reference to a vehicle test cell number may be used, with advance approval of the Administrator, provided test cell calibration records show the pertinent instrument information.

(h) Recorder charts: Identify zero, span, and enclosure gas sample traces.

(i) Enclosure barometric pressure and ambient temperature: a central laboratory barometer may be used, provided that individual test cell barometric pressures are shown to be within ±0.1 percent of the barometric pressure at the central barometer location.

(j) Temperatures: Soak area; dispensed fuel, initial and final.

(k) Fuel dispensing rate(s).

(l) Dispensed fuel volume.

(m) For methanol-fueled vehicles:

(1) Volume of sample passed through the methanol sampling system and the volume of deionized water in each impinger.

(2) The methanol concentration in the reference sample and the peak area from the GC analysis of the reference sample.

(3) The peak area of the GC analyses of the test samples (methanol).

(n) All additional information necessary for the calculations specified in §86.156-98.

[59 FR 16300, Apr. 6, 1994]

§86.156-98 Calculations; refueling test.

(a) The calculation of the net hydrocarbon mass change and methanol mass change (if applicable) in the enclosure is used to determine refueling mass emissions. The mass is calculated from initial and final hydrocarbon and methanol (if applicable) concentrations in ppm carbon, initial and final enclosure ambient temperatures, initial and final barometric pressures, and net enclosure volume using the equations of §86.143-96. For vehicles with multiple tanks, the results for each tank shall be calculated and then summed to determine overall refueling emissions.

(b) The final results for comparison with the refueling control emission standard shall be computed by dividing the total refueling mass emissions by the total gallons of fuel dispensed in the refueling test (see §86.154-98(e)(7)(i)).

(c) The results of all emission tests shall be rounded, in accordance with ASTM E 29-67 (reapproved 1980) (as referenced in §86.094-28(a)(4)(i)(B)(2)(ii)) to the number of decimal places contained in the applicable emission standard expressed to one additional significant figure.

[59 FR 16300, Apr. 6, 1994]

§86.157-98 Refueling test procedures for liquefied petroleum gas-fueled vehicles.

(a) Equipment. (1) The sampling and analytical system shall meet the specifications in §86.107-98(a) through (i).

(2) The refueling equipment nozzle specifications shall meet the requirements described in §80.32.

(b) General requirements. (1) The refueling test procedure for light-duty liquefied petroleum gas-fueled vehicles and trucks starts with the preconditioning of the vehicle followed by a refueling emissions measurement. The test is conducted by following paragraphs (c) through (f) of this section in order.

(2) Ambient temperature levels encountered by the test vehicle throughout the test sequence shall not be less than 68°F (20°C) nor more than 86°F (30°C).

(3) The vehicle shall be approximately level during all phases of the test sequence to prevent abnormal fuel distribution.

(c) Vehicle preconditioning.(1) The vehicle fuel tanks are to be filled with fuel that meets the specifications in §86.113. Fuel tanks shall be filled to 10 percent of nominal fuel tank capacity, determined to the nearest one-tenth of a U.S. gallon (0.38 liter).

(2) The vehicle shall be parked (without starting the engine) within the temperature range specified in paragraph (a)(2) of this section for a minimum of one hour and a maximum of six hours.

(d) Measurement procedure. (1) The steps prior to the actual refueling event described in §86.154-98(b) through (e)(5) shall be performed.

(2) Within one minute of obtaining the initial FID (or HFID) reading, the dispensed fuel nozzle shall be attached to the vehicle fuel receptacle, and the refueling operation shall be started. If the vehicle is equipped with a fixed liquid level gauge or other gauge or valve which could be opened to release fuel or fuel vapor during refueling, and has not received an exemption as outlined in §86.098-28(h), §86.001-28(h) or §86.004-28(h), the fixed level gauge or other gauges or valves shall be opened after the dispensing nozzle is attached, but prior to the start of the refueling operation. The dispensed fuel must be at a temperature stabilized to approximately the same temperature as the vehicle was in paragraph (c)(2) of this section. The dispensing rate must be typical of in-use dispensing rates for liquefied petroleum gas into light-duty vehicles and trucks.

(3) The fuel flow shall continue until the amount of fuel dispensed is at least 85 percent of nominal fuel tank capacity, determined to the nearest one-tenth of a U.S. gallon (0.38 liter).

(4) Following the fuel shut-off the fixed liquid level gauge or other gauges or valves, if open, shall be closed and the nozzle disconnected.

(5) The final reading of the evaporative enclosure FID (or HFID) analyzer shall be taken 60 ±5 seconds following the disconnect of the refueling nozzle. This is the final hydrocarbon concentration, C_HCf, required in §86.143. The elapsed time, in minutes, between the initial and final FID (or HFID) readings shall be recorded.

(6) For vehicles equipped with more than one fuel tank, the procedures described in this section shall be performed for each fuel tank.

(e) Records required. (1) Test: test number, system or device tested (brief description), date and time of day, instrument operated, operator, enclosure barometric pressure and temperature, recorder charts (identify zero, span, and enclosure gas traces), fuel dispensing rate(s) and dispensed fuel volume.

(2) Vehicle: ID number, manufacturer, model year, engine family, evaporative/refueling emission family, fuel tank(s) capacity, basic fuel system description and odometer reading.

(3) All pertinent instrument information including nozzle and fuel delivery system description. As an alternative, a reference to a vehicle test cell number may be used, with advance approval of the Administrator, provided test cell calibration records show the pertinent instrument information.

(4) All additional information necessary for the calculations specified in paragraph (f) of this section.

(f) Calculations.(1) The calculation of the net hydrocarbon mass change in the enclosure is used to determine refueling mass emissions. The mass is calculated from initial and final hydrocarbon concentrations in ppm carbon, initial and final enclosure ambient temperatures, initial and final barometric pressures and net volume using the equations of §86.143. For vehicles with multiple tanks, the results for each tank shall be calculated and then summed to determine overall refueling emissions.

(2) The final results for comparison with the refueling control emission standard shall be computed by dividing the total refueling mass emissions by the total gallons of fuel dispensed in the refueling test (see paragraph (d)(3) of this section).

(3) The results of all emission tests shall be rounded, in accordance with ASTM E 29-67 to the number of decimal places contained in the applicable emission standard expressed to one additional significant figure. This procedure has been incorporated by reference (see §86.1).

[59 FR 48511, Sept. 21, 1994]

§86.158-00 Supplemental Federal Test Procedures; overview.

The procedures described in §§86.158-00, 86.159-00, 86.160-00, and 86.162-00 discuss the aggressive driving (US06) and air conditioning (SC03) elements of the Supplemental Federal Test Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle operation that tests exhaust emissions with a driving schedule (US06) that tests exhaust emissions under high speeds and accelerations (aggressive driving); and a sequence of vehicle operation that tests exhaust emissions with a driving schedule (SC03) which includes the impacts of actual air conditioning operation. These test procedures (and the associated standards set forth in subpart S of this part) are applicable to light-duty vehicles and light-duty trucks.

(a) Vehicles are tested for the exhaust emissions of THC, CO, NO_X. CH₄, and CO₂. For diesel-cycle vehicles, THC is sampled and analyzed continuously according to the provisions of §86.110.

(b) Each test procedure follows the vehicle preconditioning specified in §86.132-00.

(c) US06 Test Cycle. The test procedure for emissions on the US06 driving schedule (see §86.159-00) is designed to determine gaseous exhaust emissions from light-duty vehicles and light-duty trucks while simulating high speed and acceleration on a chassis dynamometer (aggressive driving). The full test consists of preconditioning the engine to a hot stabilized condition, as specified in §86.132-00, and an engine idle period of 1 to 2 minutes, after which the vehicle is accelerated into the US06 cycle. A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(d) SC03 Test Cycle. The test procedure for determining exhaust emissions with the air conditioner operating (see §86.160-00) is designed to determine gaseous exhaust emissions from light-duty vehicles and light-duty trucks while simulating an urban trip during ambient conditions of 95°F, 100 grains of water/pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W/m ². The full test consists of vehicle preconditioning (see §86.132-00 paragraphs (o) (1) and (2)), an engine key-off 10 minute soak, an engine start, and operation over the SC03 cycle. A proportional part of the diluted exhaust is collected continuously during the engine start and the SC03 driving cycle for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(e) The emission results from the aggressive driving test (§86.159-00), air conditioning test (§86.160-00), and a FTP test (§86.130-00 (a) through (d) and (f)) (conducted on a large single roll or equivalent dynamometer) are analyzed according to the calculation methodology in §86.164-00 and compared to the applicable SFTP emission standards in subpart A of this part (§§86.108-00 and 86.109-00).

(f) These test procedures may be run in any sequence that maintains the applicable preconditioning elements specified in §86.132-00.

[61 FR 54894, Oct. 22, 1996, as amended at 70 FR 40434, July 13, 2005]

§86.158-08 Supplemental Federal Test Procedures; overview.

The procedures described in §§86.158-08, 86.159-08, 86.160-00, and 86.162-00 discuss the aggressive driving (US06) and air conditioning (SC03) elements of the Supplemental Federal Test Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle operation that tests exhaust emissions with a driving schedule (US06) that tests exhaust emissions under high speeds and accelerations (aggressive driving); and a sequence of vehicle operation that tests exhaust emissions with a driving schedule (SC03) which includes the impacts of actual air conditioning operation. These test procedures (and the associated standards set forth in subpart S of this part) are applicable to light-duty vehicles and light-duty trucks.

(a) Vehicles are tested for the exhaust emissions of THC, CO, NO_X, CH₄, and CO₂. For diesel-cycle vehicles, THC is sampled and analyzed continuously according to the provisions of §86.110.

(b) Each test procedure follows the vehicle preconditioning specified in §86.132-00.

(c) US06 Test Cycle. The test procedure for emissions on the US06 driving schedule (see §86.159-08) is designed to determine gaseous exhaust emissions from light-duty vehicles and light-duty trucks while simulating high speed and acceleration on a chassis dynamometer (aggressive driving). The full test consists of preconditioning the engine to a hot stabilized condition, as specified in §86.132-00, and an engine idle period of 1 to 2 minutes, after which the vehicle is accelerated into the US06 cycle. A proportional part of the diluted exhaust is collected continuously for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler. Optionally, as specified in §86.159-08 and in part 600 of this chapter, a proportional part of the diluted exhaust may be collected continuously in two bag samples, one representing US06 City driving and the other representing US06 Highway driving. If two bag samples are collected, for petroleum-fueled diesel-cycle vehicles for which THC is sampled and analyzed continuously according to the provisions of §86.110, the analytical system shall be configured to calculate THC for the US06 City phase and the US06 Highway phase as described in §86.159-08.

(d) SC03 Test Cycle. The test procedure for determining exhaust emissions with the air conditioner operating (see §86.160-00) is designed to determine gaseous exhaust emissions from light-duty vehicles and light-duty trucks while simulating an urban trip during ambient conditions of 95°F, 100 grains of water/pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W/m ². The full test consists of vehicle preconditioning (see §86.132-00 paragraphs (o)(1) and (2)), an engine key-off 10 minute soak, an engine start, and operation over the SC03 cycle. A proportional part of the diluted exhaust is collected continuously during the engine start and the SC03 driving cycle for subsequent analysis, using a constant volume (variable dilution) sampler or critical flow venturi sampler.

(e) The emission results from the aggressive driving test (§86.159-08), air conditioning test (§86.160-00), and FTP test (§86.130-00 (a) through (d) and (f)) (conducted on a large single roll or equivalent dynamometer) are analyzed according to the calculation methodology in §86.164-08 and compared to the applicable SFTP emission standards in subpart S of this part.

(f) These test procedures may be run in any sequence that maintains the applicable preconditioning elements specified in §86.132-00.

[71 FR 77920, Dec. 27, 2006]

§86.159-00 Exhaust emission test procedures for US06 emissions.

(a) Overview. The dynamometer operation consists of a single, 600 second test on the US06 driving schedule, as described in appendix I, paragraph (g), of this part. The vehicle is preconditioned in accordance with §86.132-00, to bring it to a warmed-up stabilized condition. This preconditioning is followed by a 1 to 2 minute idle period that proceeds directly into the US06 driving schedule during which continuous proportional samples of gaseous emissions are collected for analysis. If engine stalling should occur during cycle operation, follow the provisions of §86.136-90 (engine starting and restarting). For gasoline-fueled Otto-cycle vehicles, the composite samples collected in bags are analyzed for THC, CO, CO₂, CH₄, and NO_X. For petroleum-fueled diesel-cycle vehicles, THC is sampled and analyzed continuously according to the provisions of §86.110. Parallel bag samples of dilution air are analyzed for THC, CO, CO₂, CH₄, and NO_X.

(b) Dynamometer activities. (1) All official US06 tests shall be run on a large single roll electric dynamometer, or an approved equivalent dynamometer configuration, that satisfies the requirements of §86.108-00.

(2) Position (vehicle can be driven) the test vehicle on the dynamometer and restrain.

(3) Required US06 schedule test dynamometer inertia weight class selections are determined by the test vehicles test weight basis and corresponding equivalent weight as listed in the tabular information of §86.129-94(a) and discussed in §86.129-00 (e) and (f).

(4) Set the dynamometer test inertia weight and roadload horsepower requirements for the test vehicle (see §86.129-00 (e) and (f). The dynamometer's horsepower adjustment settings shall be set to match the force imposed during dynamometer operation with actual road load force at all speeds.

(5) The vehicle speed as measured from the dynamometer rolls shall be used. A speed vs. time recording, as evidence of dynamometer test validity, shall be supplied on request of the Administrator.

(6) The drive wheel tires may be inflated up to a gauge pressure of 45 psi (310 kPa), or the manufacturer's recommended pressure if higher than 45 psi, in order to prevent tire damage. The drive wheel tire pressure shall be reported with the test results.

(7) The driving distance, as measured by counting the number of dynamometer roll or shaft revolutions, shall be determined for the test.

(8) Four-wheel drive and all-wheel drive vehicles may be tested either in a four-wheel drive or a two-wheel drive mode of operation. In order to test in the two-wheel drive mode, four-wheel drive and all-wheel drive vehicles may have one set of drive wheels disengaged; four-wheel and all-wheel drive vehicles which can be shifted to a two-wheel mode by the driver may be tested in a two-wheel drive mode of operation.

(9) During dynamometer operation, a fixed speed cooling fan with a maximum discharge velocity of 15,000 cfm will be positioned so as to direct cooling air to the vehicle in an appropriate manner with the engine compartment cover open. In the case of vehicles with front engine compartments, the fan shall be positioned within 24 inches (61 centimeters) of the vehicle. In the case of vehicles with rear engine compartments (or if special designs make the above impractical), the cooling fan(s) shall be placed in a position to provide sufficient air to maintain vehicle cooling. The Administrator may approve modified cooling configurations or additional cooling if necessary to satisfactorily perform the test. In approving requests for additional or modified cooling, the Administrator will consider such items as actual road cooling data and whether such additional cooling is needed to provide a representative test.

(c) The flow capacity of the CVS shall be large enough to virtually eliminate water condensation in the system.

(d) Practice runs over the prescribed driving schedule may be performed at test point, provided an emission sample is not taken, for the purpose of finding the appropriate throttle action to maintain the proper speed-time relationship, or to permit sampling system adjustment.

(e) Perform the test bench sampling sequence outlined in §86.140-94 prior to or in conjunction with each series of exhaust emission measurements.

(f) Test activities. (1) The US06 consists of a single test which is directly preceded by a vehicle preconditioning in accordance with §86.132-00. Following the vehicle preconditioning, the vehicle is idled for not less than one minute and not more than two minutes. The equivalent dynamometer mileage of the test is 8.0 miles (1.29 km).

(2) The following steps shall be taken for each test:

(i) Immediately after completion of the preconditioning, idle the vehicle. The idle period is not to be less than one minute or not greater than two minutes.

(ii) With the sample selector valves in the “standby” position, connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems.

(iii) Start the CVS (if not already on), the sample pumps, the temperature recorder, the vehicle cooling fan, and the heated THC analysis recorder (diesel-cycle only). The heat exchanger of the constant volume sampler, if used, petroleum-fueled diesel-cycle THC analyzer continuous sample line should be preheated to their respective operating temperatures before the test begins.

(iv) Adjust the sample flow rates to the desired flow rate and set the gas flow measuring devices to zero.

(A) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17 cfm (0.08 liters/sec).

(B) For THC samples, the minimum FID (or HFID in the case of diesel-cycle vehicles) flow rate is 0.066 cfm (0.031 liters/sec).

(C) CFV sample flow rate is fixed by the venturi design.

(v) Attach the exhaust tube to the vehicle tailpipe(s).

(vi) Start the gas flow measuring device, position the sample selector valves to direct the sample flow into the exhaust sample bag, the dilution air sample bag, turn on the petroleum-fueled diesel-cycle THC analyzer system integrator, mark the recorder chart, and record both gas meter or flow measurement instrument readings, (if applicable).

(vii) Place vehicle in gear after starting the gas flow measuring device, but prior to the first acceleration. Begin the first acceleration 5 seconds after starting the measuring device.

(viii) Operate the vehicle according to the US06 driving schedule, as described in appendix I, paragraph (g), of this part. Manual transmission vehicles shall be shifted according to the manufacturer recommended shift schedule, subject to review and approval by the Administrator. For further guidance on transmissions see §86.128-00.

(ix) Turn the engine off 2 seconds after the end of the last deceleration (i.e., engine off at 596 seconds).

(x) Five seconds after the engine stops running, simultaneously turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1 and mark the petroleum-fueled diesel hydrocarbon recorder chart if applicable) and position the sample selector valves to the “standby” position. Record the measured roll or shaft revolutions and the No. 1 gas meter reading or flow measurement instrument.

(xi) As soon as possible, transfer the exhaust and dilution air bag samples to the analytical system and process the samples according to §86.140-94 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test.

(xii) Immediately after the end of the sample period, turn off the cooling fan, close the engine compartment cover, disconnect the exhaust tube from the vehicle tailpipe(s), and drive the vehicle from dynamometer.

(xiii) The CVS or CFV may be turned off, if desired.

[61 FR 54894, Oct. 22, 1996, as amended at 70 FR 40434, July 13, 2005; 70 FR 72928, Dec. 8, 2005]

§86.159-08 Exhaust emission test procedures for US06 emissions.

(a) Overview. The dynamometer operation consists of a single, 600 second test on the US06 driving schedule, as described in appendix I, paragraph (g), of this part. The vehicle is preconditioned in accordance with §86.132-00, to bring it to a warmed-up stabilized condition. This preconditioning is followed by a 1 to 2 minute idle period that proceeds directly into the US06 driving schedule during which continuous proportional samples of gaseous emissions are collected for analysis. US06 emissions may optionally be collected in two bag samples representing US06 City and US06 Highway emissions, as provided for in this section and in part 600 of this chapter. Emissions from seconds 0-130 and seconds 495-596 are collected in one bag to represent US06 City emissions, and emissions from seconds 130-495 are collected in a second bag to represent US06 Highway emissions. If engine stalling should occur during cycle operation, follow the provisions of §86.136-90 (engine starting and restarting). For gasoline-fueled Otto-cycle vehicles, the composite samples collected in bags are analyzed for THC, CO, CO₂, CH₄, and NO_X. For petroleum-fueled diesel-cycle vehicles, THC is sampled and analyzed continuously according to the provisions of §86.110. Parallel bag samples of dilution air are analyzed for THC, CO, CO₂, CH₄, and NO_X.

(b) Dynamometer activities. (1) All official US06 tests shall be run on a large single roll electric dynamometer, or an approved equivalent dynamometer configuration, that satisfies the requirements of §86.108-00.

(2) Position (vehicle can be driven) the test vehicle on the dynamometer and restrain.

(3) Required US06 schedule test dynamometer inertia weight class selections are determined by the test vehicles test weight basis and corresponding equivalent weight as listed in the tabular information of §86.129-94(a) and discussed in §86.129-00 (e) and (f).

(4) Set the dynamometer test inertia weight and roadload horsepower requirements for the test vehicle according to §86.129-00 (e) and (f). The dynamometer's horsepower adjustment settings shall be set to match the force imposed during dynamometer operation with actual road load force at all speeds.

(5) The vehicle speed as measured from the dynamometer rolls shall be used. A speed vs. time recording, as evidence of dynamometer test validity, shall be supplied on request of the Administrator.

(6) The drive wheel tires may be inflated up to a gauge pressure of 45 psi (310 kPa), or the manufacturer's recommended pressure if higher than 45 psi, in order to prevent tire damage. The drive wheel tire pressure shall be reported with the test results.

(7) The driving distance, as measured by counting the number of dynamometer roll or shaft revolutions, shall be determined for the test.

(8) Four-wheel drive and all-wheel drive vehicles may be tested either in a four-wheel drive or a two-wheel drive mode of operation. In order to test in the two-wheel drive mode, four-wheel drive and all-wheel drive vehicles may have one set of drive wheels disengaged; four-wheel and all-wheel drive vehicles which can be shifted to a two-wheel mode by the driver may be tested in a two-wheel drive mode of operation.

(9) During dynamometer operation, a fixed speed cooling fan with a maximum discharge velocity of 15,000 cfm will be positioned so as to direct cooling air to the vehicle in an appropriate manner with the engine compartment cover open. In the case of vehicles with front engine compartments, the fan shall be positioned within 24 inches (61 centimeters) of the vehicle. In the case of vehicles with rear engine compartments (or if special designs make the above impractical), the cooling fan(s) shall be placed in a position to provide sufficient air to maintain vehicle cooling. The Administrator may approve modified cooling configurations, additional cooling, variable speed fan(s), and/or a closed engine compartment cover if necessary to satisfactorily perform the test. In approving requests for additional or modified cooling, the Administrator will consider such items as actual road cooling data and whether such additional cooling is needed to provide a representative test. For example, the hood may be closed to provide adequate air flow to an intercooler through a factory installed hood scoop. Additionally, the Administrator may conduct certification, fuel economy and in-use testing using the additional cooling set-up approved for a specific vehicle.

(c) The flow capacity of the CVS shall be large enough to virtually eliminate water condensation in the system.

(d) Practice runs over the prescribed driving schedule may be performed at test point, provided an emission sample is not taken, for the purpose of finding the appropriate throttle action to maintain the proper speed-time relationship, or to permit sampling system adjustment.

(e) Perform the test bench sampling sequence outlined in §86.140-94 prior to or in conjunction with each series of exhaust emission measurements.

(f) Test activities. (1) The US06 consists of a single test which is directly preceded by a vehicle preconditioning in accordance with §86.132-00. Following the vehicle preconditioning, the vehicle is idled for not less than one minute and not more than two minutes. The equivalent dynamometer mileage of the test is 8.0 miles (1.29 km).

(2) The following steps shall be taken for each test:

(i) Immediately after completion of the preconditioning, idle the vehicle. The idle period is not to be less than one minute or greater than two minutes.

(ii) With the sample selector valves in the “standby” position, connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems.

(iii) Start the CVS (if not already on), the sample pumps, the temperature recorder, the vehicle cooling fan, and the heated THC analysis recorder (diesel-cycle only). The heat exchanger of the constant volume sampler, if used, petroleum-fueled diesel-cycle THC analyzer continuous sample line should be preheated to their respective operating temperatures before the test begins.

(iv) Adjust the sample flow rates to the desired flow rate and set the gas flow measuring devices to zero.

(A) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17 cfm (0.08 liters/sec).

(B) For THC samples, the minimum FID (or HFID in the case of diesel-cycle vehicles) flow rate is 0.066 cfm (0.031 liters/sec).

(C) CFV sample flow rate is fixed by the venturi design.

(v) Attach the exhaust tube to the vehicle tailpipe(s).

(vi) Start the gas flow measuring device, position the sample selector valves to direct the sample flow into the exhaust sample bag, the dilution air sample bag, turn on the petroleum-fueled diesel-cycle THC analyzer system integrator, mark the recorder chart, and record both gas meter or flow measurement instrument readings, (if applicable).

(vii) Place vehicle in gear after starting the gas flow measuring device, but prior to the first acceleration. Begin the first acceleration 5 seconds after starting the measuring device.

(viii) Operate the vehicle according to the US06 driving schedule, as described in appendix I, paragraph (g), of this part. Manual transmission vehicles shall be shifted according to the manufacturer recommended shift schedule, subject to review and approval by the Administrator. For further guidance on transmissions see §86.128-00.

(ix) Paragraphs (f)(2)(ix)(A) and (B) of this section apply to vehicles for which the manufacturer is collecting US06 City and US06 Highway emissions for subsequent analysis according to the provisions of part 600 of this chapter. Vehicles for which emissions are being collected in a single continuous sample for subsequent analysis must be tested according to paragraph (x) of this section, and this paragraph (f)(2)(ix) will not apply.

(A) At two seconds after the end of the deceleration which is scheduled to occur at 128 seconds (i.e., at 130 seconds), simultaneously switch the sample flows from the “US06 City” bags and samples to the “US06 Highway” bags and samples, switch gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1 and mark the petroleum-fueled diesel hydrocarbon recorder chart if applicable) to “standby” mode, and start gas flow measuring device No. 2 (and the petroleum-fueled diesel hydrocarbon integrator No. 2 if applicable). Before the acceleration which is scheduled to occur at 136 seconds, record the measured roll or shaft revolutions.

(B) At two seconds after the end of the deceleration which is scheduled to occur at 493 seconds (i.e., at 495 seconds), simultaneously switch the sample flows from the “US06 Highway” bags and samples to the “US06 City” bags and samples, switch off gas flow measuring device No. 2 (and the petroleum-fueled diesel hydrocarbon integrator No. 2 and mark the petroleum-fueled diesel hydrocarbon recorder chart if applicable), and start gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1 if applicable). Before the acceleration which is scheduled to occur at 500 seconds, record the measured roll or shaft revolutions and the No. 2 gas meter reading or flow measurement instrument. As soon as possible transfer the “US06 Highway” exhaust and dilution air bag samples to the analytical system and process the samples according to §86.140-94 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test.

(x) Turn the engine off 2 seconds after the end of the last deceleration (i.e., engine off at 596 seconds).

(xi) Five seconds after the engine stops running, simultaneously turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1 and mark the petroleum-fueled diesel hydrocarbon recorder chart if applicable) and position the sample selector valves to the “standby” position. Record the measured roll or shaft revolutions and the No. 1 gas meter reading or flow measurement instrument.

(xii) As soon as possible, transfer the exhaust and dilution air bag samples (or the US06 City exhaust and dilution air bag samples, if applicable) to the analytical system and process the samples according to §86.140-94 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test.

(xiii) Immediately after the end of the sample period, turn off the cooling fan, close the engine compartment cover, disconnect the exhaust tube from the vehicle tailpipe(s), and drive the vehicle from dynamometer.

(xiv) The CVS or CFV may be turned off, if desired.

[71 FR 77920, Dec. 27, 2006, as amended at 74 FR 61548, Nov. 25, 2009]

§86.160-00 Exhaust emission test procedure for SC03 emissions.

(a) Overview. The dynamometer operation consists of a single, 600 second test on the SC03 driving schedule, as described in appendix I, paragraph (h), of this part. The vehicle is preconditioned, in accordance with §86.132-00 of this subpart, to bring the vehicle to a warmed-up stabilized condition. This preconditioning is followed by a 10 minute vehicle soak (engine off) that proceeds directly into the SC03 driving schedule, during which continuous proportional samples of gaseous emissions are collected for analysis. The entire test, including the preconditioning driving, vehicle soak, and SC03 official test cycle, is either conducted in an environmental test facility or under test conditions that simulates testing in an environmental test cell (see §86.162-00 (a) for a discussion of simulation procedure approvals). The environmental test facility must be capable of providing the following nominal ambient test conditions of: 95°F air temperature, 100 grains of water/pound of dry air (approximately 40 percent relative humidity), a solar heat load intensity of 850 W/m ², and vehicle cooling air flow proportional to vehicle speed. Section 86.161-00 discusses the minimum facility requirements and corresponding control tolerances for air conditioning ambient test conditions. The vehicle's air conditioner is operated or appropriately simulated for the duration of the test procedure (except for the vehicle 10 minute soak), including the preconditioning. For gasoline-fueled Otto-cycle vehicles, the composite samples collected in bags are analyzed for THC, CO, CO₂, CH₄, and NO_X. For petroleum-fueled diesel-cycle vehicles, THC is sampled and analyzed continuously according to the provisions of §86.110. Parallel bag samples of dilution air are analyzed for THC, CO, CO₂, CH₄, and NO_X.

(b) Dynamometer activities. (1) All official air conditioning tests shall be run on a large single roll electric dynamometer or an equivalent dynamometer configuration that satisfies the requirements of §86.108-00.

(2) Position (vehicle can be driven) the test vehicle on the dynamometer and restrain.

(3) Required SC03 schedule test dynamometer inertia weight class selections are determined by the test vehicles test weight basis and corresponding equivalent weight as listed in the tabular information of §86.129-00(a) and discussed in §86.129-00 (e) and (f).

(4) Set the dynamometer test inertia weight and roadload horsepower requirements for the test vehicle (see §86.129-00 (e) and (f)). The dynamometer's horsepower adjustment settings shall be set such that the force imposed during dynamometer operation matches actual road load force at all speeds.

(5) The vehicle speed as measured from the dynamometer rolls shall be used. A speed vs. time recording, as evidence of dynamometer test validity, shall be supplied at request of the Administrator.

(6) The drive wheel tires may be inflated up to a gauge pressure of 45 psi (310 kPa), or the manufacturer's recommended pressure if higher than 45 psi, in order to prevent tire damage. The drive wheel tire pressure shall be reported with the test results.

(7) The driving distance, as measured by counting the number of dynamometer roll or shaft revolutions, shall be determined for the test.

(8) Four-wheel drive and all-wheel drive vehicles may be tested either in a four-wheel drive or a two-wheel drive mode of operation. In order to test in the two-wheel drive mode, four-wheel drive and all-wheel drive vehicles may have one set of drive wheels disengaged; four-wheel and all-wheel drive vehicles which can be shifted to a two-wheel mode by the driver may be tested in a two-wheel drive mode of operation.

(c) Vehicle and test activities for testing in a full environmental cell. The SFTP air conditioning test in an environmental test cell is composed of the following sequence of activities. Alternative procedures which appropriately simulate full environmental cell testing may be approved under the provisions of §§86.162-00(a) and 86.163-00.

(1) Drain and fill the vehicle's fuel tank to 40 percent capacity with test fuel. If a vehicle has gone through the drain and fuel sequence less than 72 hours previously and has remained under laboratory ambient temperature conditions, this drain and fill operation can be omitted (see §86.132-00(c)(2)(i)).

(2)(i) Position the variable speed cooling fan in front of the test vehicle with the vehicle's hood down. This air flow should provide representative cooling at the front of the test vehicle (air conditioning condenser and engine) during the SC03 driving schedule. See §86.161-00(e) for a discussion of cooling fan specifications.

(ii) In the case of vehicles with rear engine compartments (or if this front location provides inadequate engine cooling), an additional cooling fan shall be placed in a position to provide sufficient air to maintain vehicle cooling. The fan capacity shall normally not exceed 5300 cfm (2.50 m ³/s). If, however, it can be demonstrated that during road operation the vehicle receives additional cooling, and that such additional cooling is needed to provide a representative test, the fan capacity may be increased or additional fans used if approved in advance by the Administrator.

(3) Close all vehicle windows.

(4) Connect the emission test sampling system to the vehicle's exhaust tail pipe(s).

(5)(i) Set the environmental test cell ambient test conditions to the conditions defined in §86.161-00.

(ii) Turn on the solar heating system.

(iii) All vehicle test phases of preconditioning, soak, and the official SC03 test cycle are to be performed in this set of ambient test conditions.

(6) Set the air conditioning system controls as follows:

(i) A/C mode setting at Maximum.

(ii) Airflow setting at Recirculate, if so equipped.

(iii) Fan setting at Highest setting.

(iv) A/C Temperature setting at full cool (for automatic systems set at 72°F).

(v) Air conditioning controls should be placed in the “on” position prior to vehicle starting so that the air conditioning system is active whenever the engine is running.

(7) Start the vehicle (with air conditioning system on) and conduct a preconditioning cycle as discussed in §86.132-00(o)(1).

(i) If engine stalling should occur during any air conditioning test cycle operation, follow the provisions of §86.136-90 (Engine starting and restarting).

(ii) For manual transmission vehicles, the vehicle shall be shifted according the provisions of §86.128-00.

(8) Following the preconditioning cycle, the test vehicle (and consequently the air conditioning system) and cooling fan(s) are turned off and the vehicle is allowed to soak in the ambient conditions of paragraph (c)(5) of this section for 10 ±1 minutes.

(9) Start engine (with air conditioning system also running). Fifteen seconds after the engine starts, place vehicle in gear.

(10) Eighteen seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule.

(11) Operate the vehicle according to the SC03 driving schedule, as described in appendix I, paragraph (h), of this part.

(12) Turn the engine off 2 seconds after the end of the last deceleration (i.e., engine off at 596 seconds).

(d) Exhaust Emission Measurement Activities. The following activities are performed, when applicable, in order to meet the timing of the vehicle test and environmental facility activities.

(1) Perform the test bench sampling calibration sequence outlined in §86.140-94 prior to or in conjunction with each series of exhaust emission measurements.

(2) With the sample selector valves in the “standby” position, connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems.

(3) Start the CVS (if not already on), the sample pumps, the temperature recorder, the vehicle cooling fan, and the heated THC analysis recorder (diesel-cycle only). The heat exchanger of the constant volume sampler, if used, petroleum-fueled diesel-cycle THC analyzer continuous sample line should be preheated to their respective operating temperatures before the test begins.

(4) Adjust the sample flow rates to the desired flow rate and set the gas flow measuring devices to zero.

(i) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17 cfm (0.08 liters/sec).

(ii) For THC samples, the minimum FID (or HFID in the case of diesel-cycle vehicles) flow rate is 0.066 cfm (0.031 1/sec).

(iii) CFV sample flow rate is fixed by the venturi design.

(5) Attach the exhaust tube to the vehicle tailpipe(s).

(6) Start the gas flow measuring device, position the sample selector valves to direct the sample flow into the exhaust sample bag, the dilution air sample bag, turn on the petroleum-fueled diesel-cycle THC analyzer system integrator, mark the recorder chart, and record both gas meter or flow measurement instrument readings, if applicable.

(7) Start the engine (with air conditioning system also running). Fifteen seconds after the engine starts, place vehicle in gear.

(8) Twenty seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule.

(9) Operate the vehicle according to the SC03 driving schedule.

(10) Turn the engine off 2 seconds after the end of the last deceleration (i.e., engine off at 596 seconds).

(11) Five seconds after the engine stops running, simultaneously turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1 and mark the petroleum-fueled diesel hydrocarbon recorder chart if applicable) and position the sample selector valves to the “standby” position. Record the measured roll or shaft revolutions and the No. 1 gas meter reading or flow measurement instrument).

(12) As soon as possible, transfer the exhaust and dilution air bag samples to the analytical system and process the samples according to §86.140 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test.

(13) Immediately after the end of the sample period, turn off the cooling fan, disconnect the exhaust tube from the vehicle tailpipe(s), and drive the vehicle from dynamometer.

(14) The CVS or CFV may be turned off, if desired.

(e) NO_Xhumidity correction. Calculated NO_X exhaust emissions from air conditioning tests conducted in an environmental test cell at a nominal 100 grains of water/pound of dry air are to be corrected for humidity to 100 grains of water/pound of dry air (see the relationship of §86.164-00(d)).

[61 FR 54895, Oct. 22, 1996, as amended at 70 FR 40434, July 13, 2005; 70 FR 72928, Dec. 8, 2005]

§86.161-00 Air conditioning environmental test facility ambient requirements.

The goal of an air conditioning test facility is to simulate the impact of an ambient heat load on the power requirements of the vehicle's air conditioning compressor while operating on a specific driving cycle. The environmental facility control elements that are discussed are ambient air temperature and humidity, minimum test cell size, solar heating, and vehicle frontal air flow.

(a) Ambient air temperature. (1) Ambient air temperature is controlled, within the test cell, during all phases of the air conditioning test sequence to 95 ±2°F on average and 95 ±5°F as an instantaneous measurement.

(2) Air temperature is recorded continuously at a minimum of 30 second intervals. Records of cell air temperatures and values of average test temperatures are maintained by the manufacturer for all certification related programs.

(b) Ambient humidity. (1) Ambient humidity is controlled, within the test cell, during all phases of the air conditioning test sequence to an average of 100 ±5 grains of water/pound of dry air.

(2) Humidity is recorded continuously at a minimum of 30 second intervals. Records of cell humidity and values of average test humidity are maintained by the manufacturer for all certification related programs.

(c) Minimum test cell size. (1) The recommended minimum environmental exhaust emission test cell size is width 20 feet, length 40 feet, and height 10 feet.

(2) Test cells with smaller size dimensions may be approved by the Administrator if it can be shown that all of the ambient test condition performance requirements are satisfied.

(d) Solar heat loading. (1)(i) Acceptable types of radiant energy emitters that may be used for simulating solar heat load are:

(A) Metal halide;

(B) Quartz halogen with dichroic mirrors; and

(C) Sodium iodide.

(ii) The Administrator will approve other types of radiant energy emitters if the manufacturer can show they satisfy the requirements of this section.

(2) The height of the minimal cell size will dictate the type of radiant energy source that will satisfy the spectral distribution and uniformity definitions of this section.

(3) Radiant energy specifications. (i) Simulated solar radiant energy intensity is determined as an average of the two points measured at:

(A) Centerline of the test vehicle at the base of the windshield.

(B) Centerline of the vehicle at the base of the rear window (truck and van location defined as bottom of vertical window or where an optional window would be located).

(ii) The radiant energy intensity set point is 850 ±45 watts/square meter.

(iii) The definition of an acceptable spectral distribution is contained in the following table:

(iv) The angle of incidence of radiant energy is defined as 90 degrees from the test cell floor.

(v) The requirements for measuring the uniformity of radiant energy are:

(A) The radiant energy uniformity tolerance is ±15 percent of the radiant energy intensity set point of 850 watts/square meter.

(B) The uniformity of radiant energy intensity is measured at each point of a 0.5 meter grid over the entire footprint of the test vehicle at the elevation of one meter including the footprint edges.

(C) Radiant energy uniformity must be checked at least every 500 hours of emitter usage or every six months depending on which covers the shorter time period; and every time major changes in the solar simulation hardware occur.

(vi) The radiant energy intensity measurement instrument specifications (minimum) are:

(A) Sensitivity of 9 microvolts per watt/square meter;

(B) Response time of 1 second;

(C) Linearity of ±0.5 percent; and

(D) Cosine of ±1 percent from normalization 0-70 degree zenith angle.

(e) Vehicle frontal air flow. The Administrator will approve frontal air flow based on “blower in box” technology as an acceptable simulation of environmental air flow cooling for the air conditioning compressor and engine, provided the following requirements are satisfied.

(1) The minimum air flow nozzle discharge area must be equal or exceed the vehicle frontal inlet area. Optimum discharge area is 18 square feet (4.25 × 4.25), however, other sizes can be used.

(2) Air flow volumes must be proportional to vehicle speed. With the above optimum discharge size, the fan volume would vary from 0 cubic feet/minute (cfm) at 0 mph to approximately 95,000 cfm at 60 mph. If this fan is also the only source of cell air circulation or if fan operational mechanics make the 0 mph air flow requirement impractical, air flow of 2 mph or less will be allowed at 0 mph vehicle speed.

(3) The fan air flow velocity vector perpendicular to the axial flow velocity vector shall be less than 10 percent of the mean velocity measured at fan speeds corresponding to vehicle speeds of 20 and 40 mph.

(4)(i) Fan axial air flow velocity is measured two feet from nozzle outlet at each point of a one foot grid over the entire discharge area.

(ii) The uniformity of axial flow tolerance is 20 percent of the fan speeds corresponding to vehicle speeds of 20 and 40 mph.

(5) The instrument used to verify the air velocity must have an accuracy of 2 percent of the measured air flow speed.

(6) The fan discharge nozzle must be located 2 to 3 feet from the vehicle and 0 to 6 inches above the test cell floor during air conditioning testing. This applies to non-wind tunnel environmental test cells only.

(7) The design specifications discussed in paragraphs (e)(1) through (e)(5) of this section must be verified by the manufacturer prior to conducting certification air conditioning tests.

[61 FR 54897, Oct. 22, 1996, as amended at 70 FR 40434, July 13, 2005]

§86.162-03 Approval of alternative air conditioning test simulations.

(a) Upon petition from a manufacturer or upon the Agency's own initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test (SC03) described in §86.160-00 providing that the procedure can be run by the Administrator for SEA and in-use enforcement testing and providing that the following criteria are met:

(1) In deciding whether approvals will be granted, the Administrator will consider data showing how well the simulation matches environmental cell test data for the range of vehicles to be covered by the simulation including items such as the tailpipe emissions, air conditioning compressor load, and fuel economy.

(2) For any simulation approved under paragraph (a) of this section, the manufacturer must agree to be subject to an ongoing yearly correlation spot check as described in §86.163-00.

(3) Once a simulation is approved and used by a manufacturer for testing for a given vehicle, EPA agrees to use the simulation test procedure for all official testing conducted on that vehicle by the Agency for certification, SEA, and recall purposes, excluding spot check testing and vehicles which fail the spot check criteria as described in §86.163-00.

(4) EPA will moniter the aggregate results of spot check testing and full environmental test cells. If EPA determines, based on such aggregate results, that any simulation is producing test results consistantly below those from a full environmental test cell, EPA may review its approval of the simulation.

(b) [Reserved]

[61 FR 54899, Oct. 22, 1996]

§86.163-00 Spot check correlation procedures for vehicles tested using a simulation of the environmental test cell for air conditioning emission testing.

This section is applicable for vehicles which are tested using a simulation of the environmental test cell approved under the provisions of §86.162-00(a).

(a) The Administrator may select up to five emission data vehicles (one emission data vehicle for small volume manufacturers), including vehicles submitted for running change approval, each model year for any manufacturer undergoing the spot checking procedures of this section.

(b) Testing conducted under this section (including testing performed in an environmental test cell) will be considered as official data as described in §86.091-29 and used in determining compliance with the standards. Such testing must comply with all applicable emission standards of subpart A of this part. Retests for the purpose of emission compliance will be allowed using the procedures described in §86.091-29.

(c) Spot check procedures. (1) Subject to the limitations of paragraphs (a) and (d)(2)(iii) of this section, the Administrator may require that one or more of the test vehicles which use a simulation rather than actual testing in an environmental test cell for air conditioning emission testing be submitted at a place the Administrator will designate for air conditioning emission testing in an environmental test cell as described in §86.160-00. The Administrator may order this testing to be conducted at a manufacturer facility. All manufacturers which use a simulation instead of environmental cell testing must have access to an environment test cell meeting the requirements of §86.161-00 to perform this testing.

(2) An air conditioning emission test will be performed as described in §86.162-00 in a full environmental test cell.

(i) The results of the original simulation test and the full environmental test cell required in paragraph (c)(1) of this section are compared. In order to pass the spot check, the test results must pass both the following two criteria:

(A) The NO_X emission results of the simulation test must be at least 85% of the NO_X emission results of the environmental chamber test.

(B) The fuel consumption of the simulation test must be at least 95% of the fuel consumption of the environmental chamber test.

(ii) If either of two criteria of paragraph (c)(2)(i) of this section were not met, a retest is allowed. The manufacturer may elect to conduct either a retest of the simulation procedure or the environmental chamber testing. In order to pass the spot check, the test results must pass both the following two criteria using the retest test result.

(A) The NO_X emission results of the simulation test must be at least 85% of the NO_X emission results of the environmental chamber test.

(B) The fuel consumption of the simulation test must be at least 95% of the fuel consumption of the environmental chamber test.

(iii) If either of the two criteria of paragraph (c)(2)(ii) of this section were not met, a second retest is allowed. The procedure not selected for the first retest must be used for the second retest, yielding two test results for each procedure. In order to pass the spot check, the test results must pass both the following two criteria using the average test result for each procedure:

(A) The NO_X emission results of the simulation test must be at least 85% of the NO_X emission results of the environmental chamber test.

(B) The fuel consumption of the simulation test must be at least 95% of the fuel consumption of the environmental chamber test.

(iv) If the spot check criteria have not passed after any of the initial test, the first retest, or the second retest the spot check is considered failed.

(d) Consequences of failing a spot check. (1) If the emission results of the testing using the environmental test chamber passes all the applicable standards, those test results may be used to obtain a certificate of conformity.

(2) The Administrator will allow up to 60 days for the manufacturer to supply additional data addressing the correlation of the simulation with a full environmental test cell.

(i) If that data prove to the satisfaction of the Administrator that the simulation produces results that correlate sufficiently with the environmental test chamber, the Administrator may allow the continued use of the simulation.

(ii) Otherwise, the Administrator will determine that the simulation fails to meet adequate correlation levels with full environmental testing. As a consequence of this finding, all future air conditioning emission testing on the population of vehicles represented by the failing-spot-check test vehicle (which may include past model year configurations) will be conducted using an environment chamber or a different (or corrected) approved simulation procedure.

(iii) For each vehicle that fails a spot check, the Administrator may select up to two additional vehicles to test for the spot check that do not count against the five vehicle limit of paragraph (a) of this section.

(e) EPA will monitor the aggregate results of spot check testing and full environmental test cells. If EPA determines, based on such aggregate results, that any simulation (other than the AC1 and AC2 procedures described in paragraphs (b) and (c) of this section for the 2000, 2001, and 2002 model years) is producing test results consistently below those from a full environmental test cell, EPA may review its approval of the simulation.

[61 FR 54899, Oct. 22, 1996]

§86.164-00 Supplemental Federal Test Procedure calculations.

(a) The provisions of §86.144-94 (b) and (c) are applicable to this section except that the NO_X humidity correction factor of §86.144-94(c)(7)(iv) must be modified when adjusting SC03 environmental test cell NO_X results to 100 grains of water (see paragraph (d) of this section). These provisions provide the procedures for calculating mass emission results of each regulated exhaust pollutant for the test schedules of FTP, US06, and SC03.

(b) The provisions of §86.144-94(a) are applicable to this section. These provisions provide the procedures for determining the weighted mass emissions for the FTP test schedule (Y_wm).

(c)(1) When the test vehicle is equipped with air conditioning, the final reported test results for the SFTP composite (NMHC + NO_X) and optional composite CO standards shall be computed by the following formulas.

(i) Y_WSFTP = 0.35(Y_FTP) + 0.37(Y_SC03) + 0.28(Y_US06)

Where:

(A) Y_WSFTP = Mass emissions per mile for a particular pollutant weighted in terms of the contributions from the FTP, SC03, and US06 schedules. Values of Y_WSFTP are obtained for each of the exhaust emissions of NMHC, NO_X. and CO.

(B) Y_FTP = Weighted mass emissions per mile (Ywm) based on the measured driving distance of the FTP test schedule.

(C) Y_SC03 = Calculated mass emissions per mile based on the measured driving distance of the SC03 test schedule.

(D) Y_US06 = Calculated mass emissions per mile based on the measured driving distance of the US06 test schedule.

(ii) Composite (NMHC = NO_X) + Y_WSFTP(NMHC) W_SFTP(NO_X)

Where:

(A) Y_WSFTP(NMHC) = results of paragraph (c)(1)(i) of this section for NMHC.

(B) Y_WSFTP(NO_X) = results of paragraph (c)(1)(i) of this section for NO_X.

(2) When the test vehicle is not equipped with air conditioning, the relationship of paragraph (c)(1)(i) of this section is:

(i) Y_WSFTP = 0.72(Y_FTP) + 0.28(Y_US06)

Where:

(A) Y_WSFTP = Mass emissions per mile for a particular pollutant weighted in terms of the contributions from the FTP and US06 schedules. Values of Y_WSFTP are obtained for each of the exhaust emissions of NMHC, NO_X. and CO.

(B) Y_FTP = Weighted mass emissions per mile (Ywm) based on the measured driving distance of the FTP test schedule.

(C) Y_US06 = Calculated mass emissions per mile based on the measured driving distance of the US06 test schedule.

(ii) Composite (NMHC + NO_X) = Y_WSFTP(NMHC) + Y_WSFTP(NO_X)

Where:

(A) Y_WSFTP(NMHC) = results of paragraph (c)(2)(i) of this section for NMHC.

(B) Y_WSFTP(NO_X) = results of paragraph (c)(2)(i) of this section for NO_X.

(d) The NO_X humidity correction factor for adjusting NO_X test results to the environmental test cell air conditioning ambient condition of 100 grains of water/pound of dry air is:

K_H (100) = 0.8825/[1-0.0047(H-75)]

Where:

H = measured test humidity in grains of water/pound of dry air.

[61 FR 54900, Oct. 22, 1996, as amended at 70 FR 40434, July 13, 2005]

§86.164-08 Supplemental Federal Test Procedure calculations.

(a) The provisions of §86.144-94 (b) and (c) are applicable to this section except that the NO_X humidity correction factor of §86.144-94(c)(7)(iv) must be modified when adjusting SC03 environmental test cell NO_X results to 100 grains of water according to paragraph (d) of this section. These provisions provide the procedures for calculating mass emission results of each regulated exhaust pollutant for the test schedules of FTP, US06, and SC03.

(b) The provisions of §86.144-94(a) are applicable to this section. These provisions provide the procedures for determining the weighted mass emissions for the FTP test schedule (Y_wm).

(c)(1) When the test vehicle is equipped with air conditioning, the final reported test results for the SFTP composite (NMHC + NO_X) and optional composite CO standards shall be computed by the following formulas.

(i) Y_WSFTP = 0.35(Y_FTP) + 0.37(Y_SC03) + 0.28(Y_US06)

Where:

(A) Y_WSFTP = Mass emissions per mile for a particular pollutant weighted in terms of the contributions from the FTP, SC03, and US06 schedules. Values of Y_WSFTP are obtained for each of the exhaust emissions of NMHC, NO_X and CO.

(B) Y_FTP = Weighted mass emissions per mile (Y_WM) based on the measured driving distance of the FTP test schedule.

(C) Y_SC03 = Calculated mass emissions per mile based on the measured driving distance of the SC03 test schedule.

(D)(1) Y_US06 = Calculated mass emissions per mile based on the measured driving distance of the US06 test schedule; or,

(2) In the case of a 2-phase US06 test run according to the provisions of §86.159-08(f)(2) and part 600 of this chapter:

YUS06 = Calculated mass emissions per mile, using the summed mass emissions of the “US06 City” phase and the “US06 Highway” phase, based on the measured driving distance of the US06 test schedule. The “US06 City” phase shall be sampled during seconds 0-130 and from 495 seconds until five seconds after the engine stops running (e.g. 602 or 603 seconds) of the US06 driving schedule. The “US06 Highway” phase shall be sampled during seconds 130-495 of the US06 driving schedule),

(ii) Composite (NMHC + NO_X) = Y_WSFTP(NMHC) + Y_WSFTP(NO_X)

Where:

(A) Y_WSFTP(NMHC) = results of paragraph (c)(1)(i) of this section for NMHC.

(B) Y_WSFTP(NO_X) = results of paragraph (c)(1)(i) of this section for NO_X.

(2) When the test vehicle is not equipped with air conditioning, the final reported test results for the SFTP composite (NMHC + NO_X) and optional composite CO standards shall be computed by the following formulas.

(i) Y_WSFTP = 0.72(Y_FTP) + 0.28(Y_US06)

Where:

(A) Y_WSFTP = Mass emissions per mile for a particular pollutant weighted in terms of the contributions from the FTP and US06 schedules. Values of Y_WSFTP are obtained for each of the exhaust emissions of NMHC, NO_X and CO.

(B) Y_FTP = Weighted mass emissions per mile (Ywm) based on the measured driving distance of the FTP test schedule.

(C)(1) Y_US06 = Calculated mass emissions per mile based on the measured driving distance of the US06 test schedule; or,

(2) In the case of a 2-phase US06 test run according to the provisions of §86.159-08(f)(2) and part 600 of this chapter:

YUS06 = Calculated mass emissions per mile, using the summed mass emissions of the “US06 City” phase and the “US06 Highway” phase, based on the measured driving distance of the US06 test schedule. The “US06 City” phase shall be sampled during seconds 0-130 and from 495 seconds until five seconds after the engine stops running (e.g. 602 or 603 seconds) of the US06 driving schedule. The “US06 Highway” phase shall be sampled during seconds 130-495 of the US06 driving schedule),

(ii) Composite (NMHC + NO_X) = Y_WSFTP(NMHC) + Y_WSFTP(NO_X)

Where:

(A) Y_WSFTP(NMHC) = results of paragraph (c)(2)(i) of this section for NMHC.

(B) Y_WSFTP(NO_X) = results of paragraph (c)(2)(i) of this section for NO_X.

(d) The NO_X humidity correction factor for adjusting NO_X test results to the environmental test cell air conditioning ambient condition of 100 grains of water/pound of dry air is:

K_H (100) = 0.8825/[1-0.0047(H-75)]

Where:

H = measured test humidity in grains of water/pound of dry air.

[71 FR 77922, Dec. 27, 2006, as amended at 74 FR 61548, Nov. 25, 2009]

§86.166-12 [Reserved]