Control of Emissions of Air Pollution From 2004 and Later Model Year Heavy-Duty Highway Engines and Vehicles; Revision of Light-Duty Truck Definition

摘要

We are proposing to take several actions relating to emission standards and test procedures for heavy-duty engines and vehicles intended for operation on roads and highways. The proposed provisions are for the 2004 and later model years. First, we are proposing new more stringent emissions standards and related provisions for all heavy-duty Otto-cycle (e.g., gasoline-fueled) engines and vehicles. Vehicles in this category include large full size pick-up trucks, full size cargo and passenger vans, and the largest sport utility vehicles. For heavy-duty Otto-cycle engines and vehicles, today's proposal would reduce the standards for oxides of nitrogen and hydrocarbons by approximately 75 percent from current standards. Second, we propose to reaffirm that the NMHC+NO X standard promulgated in October, 1997 for diesel heavy-duty engines is both necessary and feasible. This standard represents about a 50 percent reduction in emissions of nitrogen oxides, as well as reductions in hydrocarbons, from diesel trucks and buses. Third, we are proposing to require on-board diagnostics systems for all heavy-duty vehicles and engines at or below 14,000 lbs gross vehicle weight rating (GVWR), and t