Search Results

The characteristics of methanol and ethanol as highway motor vehicle fuels are contrasted with those of conventional gasolines and diesel fuels. The implications of the physical and chemical differences of these fuels for motor vehicle design and emissions are discussed. Potential material compatibility concerns, such as elastomer swelling and metal corrosion, and safety concerns, such as fire hazard, flame luminosity, and human toxicity are examined. A number of possible air quality impacts are examined including changes in ozone, carbon monoxide, oxides of nitrogen, particulate matter, toxic compounds (benzene, aldehydes, 1,3-butadiene), and global climate “greenhouse” gases (carbon dioxide, methane, nitrous oxide).

Apportionment of air pollution to sources requires knowledge of source emission strengths and/or chemical and physical characteristics. The literature is deficient in data useful for this purpose for heavy-duty motor vehicles, which can be important sources of air pollution in certain microenvironments. Emission factors are developed in this study for heavy-duty gasoline trucks using chassis dynamometer simulations of urban driving conditions. The sensitivity of the emissions to such considerations as the characteristics of the speed-time driving schedule, vehicle payload, and chassis configuration are examined. Emissions characterization includes total and individual hydrocarbons, aldehydes, carbon monoxide, oxides of nitrogen, total particulate matter, particulate organics, lead, bromine, chlorine, and the fraction of total particulate less than 2 μm. Preliminary comparisons of emissions obtained using transient engine and transient chassis test procedures are also reported.