Motor Vehicles in the 1990s: Emerging Environmental Constraints on Current Fuels, and Emissions and Energy Trade-Offs Related to Nonpetroleum Alternatives.

摘要

Manufacturers of motor vehicles and engines may face substantial compliance challenges because of existing or proposed environmental regulations. Among the challenges due to existing regulations is the need for improved control of evaporative emissions from gasoline vehicles and emissions of particulate matter from heavy-duty diesel trucks. Potential future challenges could arise from the need to control refueling emissions and from more stringent emission standards for hydrocarbons and oxides of nitrogen. Virtually all of these regulations require technological changes to vehicles and engines, assuming that gasoline and diesel fuel remain as the operating fuels. However, recent speculation has centered on the possibility of meeting some or all of these regulatory challenges with alternative fuels such as natural gas or methanol. This study addresses that possibility by examining current and potential standards, characterizing vehicles that use alternative fuels, and assessing -- via an informal canvass of manufacturers -- the likelihood of meeting the regulations with both conventional and alternative fuels. A selective literature review compares emissions, energy use, and costs associated with both types of fuels. Finally, a plausible scenario of introducing methanol- fueled autos and light trucks by the early 1990s is defined as the basis for examining changes in emission levels nationally. While the overall reduction -- from all transportation sources -- of reactive hydrocarbons and oxides of nitrogen due to these vehicles is less than 1% by 1997, the potential remains for greater levels of reduction within urbanized areas, especially if tax-based incentives and other measures are used to encourage the use of vehicles powered by alternative fuels. 68 refs., 2 figs., 23 tabs. (ERA citation 13:054122)