(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]