Alternative fuels are being proposed for improving ambient air quality, particularly in the urban environment. City buses powered by diesel engines are targeted for lowering particulate emissions earlier than truck engines because of public demand for improved air quality. The characteristics of alternative fuels including methanol, ethanol, natural gas, and propane for use in diesel based engines are reviewed. Engine design options and considerations are discussed for different fuel options. The impact of fuel energy density on extra vehicle weight, range, and fueling logistics are presented. Development and field experience are presented for a compressed natural gas (CNG) Cummins L10 engine used in urban bus and utility vehicles. Results show that the engine performance and bus emission goals for U.S. EPA in 1993 are achieved. CNG L10 is proceeding to limited production. New components developed and supporting technology needs are highlighted. (A)
Samenvatting