['Air Programs']
['Air Emissions']
06/26/2024
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This subpart I specifies how to apply the test procedures of this part for light-duty vehicles, light-duty trucks, and heavy-duty vehicles at or below 14,000 pounds GVWR that are subject to chassis testing for exhaust emissions under 40 CFR part 86, subpart S. For these vehicles, references in this part 1066 to the standard-setting part include subpart H of this part and this subpart I.
(a) Use the procedures detailed in this subpart to measure vehicle emissions over a specified drive schedule in conjunction with subpart E of this part. Where the procedures of subpart E of this part differ from this subpart I, the provisions in this subpart I take precedence.
(b) Collect samples of every pollutant for which an emission standard applies, unless specified otherwise.
(c) This subpart covers the following test procedures:
(1) The Federal Test Procedure (FTP), which includes the general driving cycle. This procedure is also used for measuring evaporative emissions. This may be called the conventional test since it was adopted with the earliest emission standards.
(i) The FTP consists of one Urban Dynamometer Driving Schedule (UDDS) as specified in paragraph (a) of appendix I to 40 CFR part 86, followed by a 10-minute soak with the engine off and repeat driving through the first 505 seconds of the UDDS. Note that the UDDS represents about 7.5 miles of driving in an urban area. Engine startup (with all accessories turned off), operation over the initial UDDS, and engine shutdown make a complete cold-start test. The hot-start test consists of the first 505 seconds of the UDDS following the 10-minute soak and a hot-running portion of the UDDS after the first 505 seconds. The first 505 seconds of the UDDS is considered the transient portion; the remainder of the UDDS is considered the stabilized (or hot-stabilized) portion. The hot-stabilized portion for the hot-start test is generally measured during the cold-start test; however, in certain cases, the hot-start test may involve a second full UDDS following the 10-minute soak, rather than repeating only the first 505 seconds. See §§1066.815 and 1066.820.
(ii) Evaporative emission testing includes a preconditioning drive with the UDDS and a full FTP cycle, including exhaust measurement, followed by evaporative emission measurements. In the three-day diurnal test sequence, the exhaust test is followed by a running loss test consisting of a UDDS, then two New York City Cycles as specified in paragraph (e) of appendix I to 40 CFR part 86, followed by another UDDS; see 40 CFR 86.134. Note that the New York City Cycle represents about 1.18 miles of driving in a city center. The running loss test is followed by a high-temperature hot soak test as described in 40 CFR 86.138 and a three-day diurnal emission test as described in 40 CFR 86.133. In the two-day diurnal test sequence, the exhaust test is followed by a low-temperature hot soak test as described in 40 CFR 86.138-96(k) and a two-day diurnal emission test as described in 40 CFR 86.133-96(p).
(iii) Refueling emission tests for vehicles that rely on integrated control of diurnal and refueling emissions includes vehicle operation over the full FTP test cycle corresponding to the three-day diurnal test sequence to precondition and purge the evaporative canister. For non-integrated systems, there is a preconditioning drive over the UDDS and a refueling event, followed by repeated UDDS driving to purge the evaporative canister. The refueling emission test procedures are described in 40 CFR 86.150 through 86.157.
(2) The US06 driving cycle is specified in paragraph (g) of appendix I to 40 CFR part 86. Note that the US06 driving cycle represents about 8.0 miles of relatively aggressive driving.
(3) The SC03 driving cycle is specified in paragraph (h) of appendix I to 40 CFR part 86. Note that the SC03 driving schedule represents about 3.6 miles of urban driving with the air conditioner operating.
(4) The hot portion of the LA-92 driving cycle is specified in paragraph (c) of appendix I to 40 CFR part 86. Note that the hot portion of the LA-92 driving cycle represents about 9.8 miles of relatively aggressive driving for commercial trucks. This driving cycle applies for heavy-duty vehicles above 10,000 pounds GVWR and at or below 14,000 pounds GVWR only for vehicles subject to Tier 3 standards.
(5) The Highway Fuel Economy Test (HFET) is specified in appendix I to 40 CFR part 600. Note that the HFET represents about 10.2 miles of rural and freeway driving with an average speed of 48.6 mi/hr and a maximum speed of 60.0 mi/hr. See §1066.840.
(6) Cold temperature standards apply for NMOG+NO X (or NMHC), PM, and CO emissions when vehicles operate over the FTP at a nominal temperature of −7 °C. See subpart H of this part.
(7) Emission measurement to determine air conditioning credits for greenhouse gas standards. In this optional procedure, manufacturers operate vehicles over repeat runs of the AC17 test sequence to allow for calculating credits as part of demonstrating compliance with CO 2 emission standards. The AC17 test sequence consists of a UDDS preconditioning drive, followed by emission measurements over the SC03 and HFET driving cycles. See §1066.845.
(8) The mid-temperature intermediate soak FTP is specified as the procedure for Partial Soak Emission Testing in Section E4.4 of California ARB's PHEV Test Procedures for plug-in hybrid electric vehicles, in Part II Section I.7 of California ARB's LMDV Test Procedures for other hybrid electric vehicles, and in Part II, Section B.9.1 and B.9.3 of California ARB's LMDV Test Procedures for other vehicles (both incorporated by reference, see §1066.1010).
(9) The early driveaway FTP is specified as the procedure for Quick Drive-Away Emission Testing in Section E4.5 of California ARB's PHEV Test Procedures for plug-in hybrid electric vehicles, in Part II Section I.8 of California ARB's LMDV Test Procedures for other hybrid electric vehicles, and in Part II, Section B.9.2 and B.9.4 of California ARB's LMDV Test Procedures for other vehicles (both incorporated by reference, see §1066.1010). Additionally, vehicle speed may not exceed 0.0 mi/hr until 7.0 seconds into the driving schedule and vehicle speed may not exceed 2.0 mi/hr from 7.1 through 7.9 seconds.
(10) The high-load PHEV engine starts US06 is specified in Section E7.2 of California ARB's PHEV Test Procedures using the cold-start US06 Charge-Depleting Emission Test (incorporated by reference, see §1066.1010).
(d) The following provisions apply for all testing:
(1) Ambient temperatures encountered by the test vehicle must be (20 to 30) °C, unless otherwise specified. Where ambient temperature specifications apply before or between test measurements, the vehicle may be exposed to temperatures outside of the specified range for up to 10 minutes to account for vehicle transport or other actions to prepare for testing. The temperatures monitored during testing must be representative of those experienced by the test vehicle. For example, do not measure ambient temperatures near a heat source.
(2) Do not operate or store the vehicle at an incline if good engineering judgment indicates that it would affect emissions.
(3) If a test is void after collecting emission data from previous test segments, the test may be repeated to collect only those data points needed to complete emission measurements. You may combine emission measurements from different test runs to demonstrate compliance with emission standards.
(4) Prepare vehicles for testing as described in §1066.810.
(e) The following figure illustrates the FTP test sequence for measuring exhaust and evaporative emissions:
Figure 1 to Paragraph (e)—FTP Test Sequence
[79 FR 23823, Apr. 28, 2014, as amended at 80 FR 9123, Feb. 19, 2015; 81 FR 74213, Oct. 25, 2016; 86 FR 34583, Jun. 29, 2021; 89 FR 28213, Apr. 18, 2024]
['Air Programs']
['Air Emissions']