Section 1051.501 - What procedures must I use to test my vehicles or engines?This section describes test procedures that you use to determine whether vehicles meet the emission standards of this part. See § 1051.235 to determine when testing is required for certification. See subpart D of this part for the production-line testing requirements.
(a)Snowmobiles. For snowmobiles, use the equipment and procedures for spark-ignition engines in 40 CFR part 1065 to determine whether your snowmobiles meet the duty-cycle emission standards in § 1051.103 . Measure the emissions of all the pollutants we regulate in § 1051.103 . Measure CO2, N2O, and CH4 as described in § 1051.235 . Use the duty cycle specified in § 1051.505 .(b)Motorcycles and ATVs. For motorcycles and ATVs, use the equipment, procedures, and duty cycle in 40 CFR part 86, subpart F, to determine whether your vehicles meet the exhaust emission standards in § 1051.105 or § 1051.107 . Measure the emissions of all the pollutants we regulate in § 1051.105 or § 1051.107 . Measure CO2, N2O, and CH4 as described in § 1051.235 . If we allow you to certify ATVs based on engine testing, use the equipment, procedures, and duty cycle described or referenced in the section that allows engine testing. For motorcycles with engine displacement at or below 169 cc and all ATVs, use the driving schedule in paragraph (b) of appendix I to 40 CFR part 86 . For all other motorcycles, use the driving schedule in paragraph (a) of Appendix I to part 86. With respect to vehicle-speed governors, test motorcycles and ATVs in their ungoverned configuration, unless we approve in advance testing in a governed configuration. We will only approve testing in a governed configuration if you can show that the governor is permanently installed on all production vehicles and is unlikely to be removed in use. With respect to engine-speed governors, test motorcycles and ATVs in their governed configuration. Run the test engine, with all emission-control systems operating, long enough to stabilize emission levels; you may consider emission levels stable without measurement if you accumulate 12 hours of operation.(c)Permeation testing.(1) Use the equipment and procedures specified in § 1051.515 to measure fuel tank permeation emissions.(2) To measure fuel-line permeation emissions, use the equipment and procedures specified in SAE J30 as described in 40 CFR 1060.810 . Prior to permeation testing, precondition the fuel line by filling it with the fuel specified in paragraph (d)(3) of this section, sealing the openings, and soaking it for 4 weeks at (23 ±5) °C. Use the fuel specified in paragraph (d)(3) of this section. Perform daily measurements for 14 days, except that you may omit up to two daily measurements in any seven-day period. Maintain an ambient temperature of (23 ±2) °C throughout the sampling period, except for intervals up to 30 minutes for weight measurements.(d)Fuels. Use the fuels meeting the following specifications:(1)Exhaust. Use the fuels and lubricants specified in 40 CFR part 1065, subpart H, for all the exhaust testing we require in this part. For service accumulation, use the test fuel or any commercially available fuel that is representative of the fuel that in-use engines will use. The following provisions apply for using specific fuel types: (i) For gasoline-fueled engines, use the grade of gasoline specified in 40 CFR 1065.710(c) for general testing. You may alternatively use ethanol-blended fuel meeting the specifications described in 40 CFR 1065.710(b) for general testing without our advance approval. If you use the ethanol-blended fuel for certifying a given engine family, you may also use it for production-line testing or any other testing you perform for that engine family under this part. If you use the ethanol-blended fuel for certifying a given engine family, we may use the ethanol-blended fuel or the specified neat gasoline test fuel with that engine family.(ii) For diesel-fueled engines, use either low-sulfur diesel fuel or ultra low-sulfur diesel fuel meeting the specifications in 40 CFR 1065.703 . If you use sulfur-sensitive technology as defined in 40 CFR 1039.801 and you measure emissions using ultra low-sulfur diesel fuel, you must add a permanent label near the fuel inlet with the following statement: "ULTRA LOW SULFUR FUEL ONLY".(2)Fuel tank permeation.(i) For the preconditioning soak described in § 1051.515(a)(1) and fuel slosh durability test described in § 1051.515(d)(3) , use the fuel specified in 40 CFR 1065.710(b) , or the fuel specified in 40 CFR 1065.710(c) blended with 10 percent ethanol by volume. As an alternative, you may use Fuel CE10, which is Fuel C as specified in ASTM D471 (see 40 CFR 1060.810 ) blended with 10 percent ethanol by volume.(ii) For the permeation measurement test in § 1051.515(b) , use the fuel specified in 40 CFR 1065.710(c) . As an alternative, you may use any of the fuels specified in paragraph (d)(2)(i) of this section.(3)Fuel hose permeation. Use the fuel specified in 40 CFR 1065.710(b) , or the fuel specified in 40 CFR 1065.710(c) blended with 10 percent ethanol by volume for permeation testing of fuel lines. As an alternative, you may use Fuel CE10, which is Fuel C as specified in ASTM D471 (see 40 CFR 1060.810 ) blended with 10 percent ethanol by volume.(e)Engine stabilization. Instead of the provisions of 40 CFR 1065.405 , you may consider emission levels stable without measurement after 12 hours of engine operation.(g)Special procedures for engine testing.(1) You may use special or alternate procedures, as described in § 1065.10 of this chapter.(2) We may reject data you generate using alternate procedures if later testing with the procedures in part 1065 of this chapter shows contradictory emission data.(3) You may test engines using a test speed based on the point of maximum power if that represents in-use operation better than testing based on maximum test speed.(h)Special procedures for vehicle testing.(1) You may use special or alternate procedures, as described in paragraph (f)(3) of this section.(2) We may reject data you generate using alternate procedures if later testing with the otherwise specified procedures shows contradictory emission data.(3)(i) The test procedures specified for vehicle testing are intended to produce emission measurements equivalent to those that would result from measuring emissions during in-use operation using the same vehicle configuration. If good engineering judgment indicates that use of the procedures in this part for a vehicle would result in measurements that are not representative of in-use operation of that vehicle, you must notify us. If we determine that using these procedures would result in measurements that are significantly unrepresentative and that changes to the procedures will result in more representative measurements that do not decrease the stringency of emission standards or other requirements, we will specify changes to the procedures. In your notification to us, you should recommend specific changes you think are necessary.(ii) You may ask to use emission data collected using other test procedures, such as those of the California Air Resources Board or the International Organization for Standardization. We will allow this only if you show us that these data are equivalent to data collected using our test procedures.(iii) You may ask to use alternate procedures that produce measurements equivalent to those obtained using the specified procedures. In this case, send us a written request showing that your alternate procedures are equivalent to the test procedures of this part. If you prove to us that the procedures are equivalent, we will allow you to use them. You may not use alternate procedures until we approve them.(iv) You may ask to use special test procedures if your vehicle cannot be tested using the specified test procedures (for example, it is incapable of operating on the specified transient cycle). In this case, send us a written request showing that you cannot satisfactorily test your engines using the test procedures of this part. We will allow you to use special test procedures if we determine that they would produce emission measurements that are representative of those that would result from measuring emissions during in-use operation. You may not use special procedures until we approve them.67 FR 68347, Nov. 8, 2002, as amended at 69 FR 2442, Jan. 15, 2004; 70 FR 40499, July 13, 2005; 73 FR 59253, Oct. 8, 2008; 74 FR 56511, Oct. 30, 2009; 80 FR 9113, Feb. 19, 2015; 86 FR 34516, June 29, 2021; 88 FR 4666, Jan. 24, 2023 86 FR 34516, 7/29/2021; 88 FR 4666, 3/27/2023