Evaporative Emission Regulations for Light Duty Vehicles and Trucks (6 gram standard): Revision to Environmental and Economic Impact Statement for the 1978 Evaporative Emission Regulations.

摘要

The regulation changes the current 'carbon trap' testing method for evaporative emissions set forth in the Code of Federal Regulations (40 CFR, 86.177-17) for light duty vehicles and light duty trucks. The current "carbon trap" method for measuring evaporative emissions has been found, through testing with a more accurate measurement method, to underestimate actual evaporative emissions by as much as fifteen times. The more accurate testing method is the Society of Automobile Engineers (SAW) recommended procedure for measuring evaporative emissions (SAE J171a) and evolves collecting the evaporative emissions in a large sealed enclosure containing the test vehicle. The results of the 1972 EPa Society of Automobile Engineers (SAW) by the enclosure method showed evaporative emissions to be at a 24 g/test level, which is about 12 times the 2 g/test standard which must currently be met when testing is done by the "carbon trap" method. Thus, the amount of control thought to exist for evaporative emissions does not in actuality exist.