['Air Programs']
['Mobile Emission Sources']
08/01/2024
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Manufacturers may generate credits applicable to the CO 2 fleet average program described in §86.1865-12 by implementing specific air conditioning system technologies designed to reduce air conditioning refrigerant leakage over the useful life of their passenger automobiles and/or light trucks (including MDPV); only the provisions of paragraph (a) of this section apply for non-MDPV heavy-duty vehicles. Credits shall be calculated according to this section for each air conditioning system that the manufacturer is using to generate CO 2 credits.
(a) Calculate an annual rate of refrigerant leakage from an air conditioning system as follows, expressed to the nearest 0.1 grams per year:
(1) Through model year 2026, calculate leakage rates according to the procedures specified in SAE J2727 FEB2012 (incorporated by reference, see §86.1). In doing so, the refrigerant permeation rates for hoses shall be determined using the procedures specified in SAE J2064 (incorporated by reference, §86.1). The procedures of SAE J2727 may be used to determine leakage rates for HFC-134a and HFO-1234yf; manufacturers should contact EPA regarding procedures for other refrigerants.
(2) For model years 2027 through 2030, calculate leakage rates according to the procedures specified in SAE J2727 SEP2023 (incorporated by reference, §86.1).
(b) The CO 2 -equivalent gram per mile leakage reduction used to calculate the total leakage credits generated by an air conditioning system shall be determined according to this paragraph (b), separately for passenger automobiles and light trucks, and rounded to the nearest tenth of a gram per mile:
(1) Passenger automobile leakage credit for an air conditioning system:
Equation 1 to Paragraph (b)(1)
Where:
MaxCredit is 12.6 (grams CO 2 -equivalent/mile) for air conditioning systems using HFC-134a, and 13.8 (grams CO 2 -equivalent/mile) for air conditioning systems using a refrigerant with a lower global warming potential.
LeakScore means the annual refrigerant leakage rate determined according to paragraph (a) of this section. If the calculated rate is less than 8.3 grams/year (or 4.1 grams/year for systems using only electric compressors), the rate for the purpose of this formula shall be 8.3 grams/year (or 4.1 grams/year for systems using only electric compressors).
GWPREF means the global warming potential of the refrigerant as indicated in paragraph (e) of this section or as otherwise determined by the Administrator.
HiLeakDis means the high leak disincentive, which is determined using the following equation, except that if GWPREF is greater than 150 or if the calculated result of the equation is less than zero, HiLeakDis shall be set equal to zero, or if the calculated result of the equation is greater than 1.8 g/mi, HiLeakDis shall be set to 1.8 g/mi:
Equation 2 to Paragraph (b)(1)
Where:
LeakThreshold = 11.0 for air conditioning systems with a refrigerant capacity less than or equal to 733 grams; or LeakThreshold = [ Refrigerant Capacity × 0.015] for air conditioning systems with a refrigerant capacity greater than 733 grams, where Refrigerant Capacity is the maximum refrigerant capacity specified for the air conditioning system, in grams.
(2) Light truck leakage credit for an air conditioning system:
Equation 3 to Paragraph (b)(2)
Where:
MaxCredit is 15.6 (grams CO 2 -equivalent/mile) for air conditioning systems using HFC-134a, and 17.2 (grams CO 2 -equivalent/mile) for air conditioning systems using a refrigerant with a lower global warming potential.
LeakScore means the annual refrigerant leakage rate determined according to paragraph (a) of this section. If the calculated rate is less than 10.4 grams/year (or 5.2 grams/year for systems using only electric compressors), the rate for the purpose of this formula shall be 10.4 grams/year (or 5.2 grams/year for systems using only electric compressors).
GWPREF means the global warming potential of the refrigerant as indicated in paragraph (e) of this section or as otherwise determined by the Administrator.
HiLeakDis means the high leak disincentive, which is determined using the following equation, except that if GWPREF is greater than 150 or if the calculated result of the equation is less than zero, HiLeakDis shall be set equal to zero, or if the calculated result of the equation is greater than 2.1 g/mi, HiLeakDis shall be set to 2.1 g/mi:
Equation 4 to Paragraph (b)(2)
Where:
LeakThreshold = 11.0 for air conditioning systems with a refrigerant capacity less than or equal to 733 grams; or LeakThreshold = [ Refrigerant Capacity × 0.015] for air conditioning systems with a refrigerant capacity greater than 733 grams, where Refrigerant Capacity is the maximum refrigerant capacity specified for the air conditioning system, in grams.
(c) Calculate the total leakage credits generated by the air conditioning system as follows:
(1) Calculate a total leakage credit in megagrams separately for passenger automobiles and light trucks using the following equation:
Equation 5 to Paragraph (c)(1)
Where:
Leakage = the CO 2 -equivalent leakage credit value in grams per mile determined in paragraph (b) of this section, subject to the maximum values specified in paragraph (c)(2) of this section.
Production = The total number of passenger automobiles or light trucks, whichever is applicable, produced with the air conditioning system to which to the leakage credit value from paragraph (b)(1) or (2) of this section applies.
VLM = vehicle lifetime miles, which for passenger automobiles shall be 195,264 and for light trucks shall be 225,865.
(2) Total leakage credits may not exceed the following maximum per-vehicle values in model years 2027 through 2030:
| Model year | Passenger automobiles | Light trucks |
|---|---|---|
| 2027 | 11.0 | 13.8 |
| 2028 | 8.3 | 10.3 |
| 2029 | 5.5 | 6.9 |
| 2030 | 2.8 | 3.4 |
(d) The results of paragraph (c) of this section, rounded to the nearest whole number, shall be included in the manufacturer's credit/debit totals calculated in §86.1865-12(k)(5).
(e) The following values for refrigerant global warming potential ( GWPREF), or alternative values as determined by the Administrator, shall be used in the calculations of this section. The Administrator will determine values for refrigerants not included in this paragraph (e) upon request by a manufacturer.
(1) For HFC-134a, GWPREF = 1430;
(2) For HFC-152a, GWPREF = 124;
(3) For HFO-1234yf, GWPREF 1; and
(4) For CO 2 , GWPREF = 1.
[77 FR 63165, Oct. 15, 2012, as amended at 81 FR 73996, Oct. 25, 2016; 86 FR 74525, Dec. 30, 2021; 89 FR 28194, Apr. 18, 2024]
['Air Programs']
['Mobile Emission Sources']