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The importance of reducing NOx emissions in many urban areas has led to the development of compressed natural gas (CNG) engines for transit bus applications. These lower emission vehicles have led potential operators to question the applicability of this new technology in service. To address the concerns of transit operators, especially those with small systems, Yolo County Transit Authority (YCTA) put into service four CNG-powered BIA-Orion V buses with Cummins L10G engines. Performance data were collected for these four vehicles and four control diesel buses over an 18-month period. The results demonstrated that CNG vehicles can be successfully incorporated into small operator fleets and can perform as well as or better than their diesel counterparts.

As part of the California Alternative-Fueled Truck Demonstration, sponsored by the California Energy Commission (CEC) and the South Coast Air Quality Management District (SCAQMD), a methanol-fueled Ford 6.6L MX engine was installed in an 8-bay bottled water delivery truck operated by Arrowhead Drinking Water Company in Los Angeles, California. The engine was an in-line 6-cylinder, naturally aspirated, spark-ignited, four-stroke engine rated at 170 hp (127 kW). The truck operated in regular service at Arrowhead from August 1990 through January 1992. Arrowhead personnel recorded daily operating data on mileage, engine hours, and fuel consumption for the methanol truck, as well as for an equivalent diesel truck used for experimental control. The methanol truck was fueled at a nearby commercial M85 fueling station.

Urban areas in Taiwan frequently experience unhealthy levels of particulate, ozone, and carbon monoxide. The Taiwan Environmental Protection Administration, formed in 1987, has begun an aggressive program to improve air quality by addressing all major sources of air pollution. Mobile emissions sources are responsible for over 90 percent of CO, NOx, and HC emissions in the Taipei area. New emissions standards for light-duty vehicles and motorcycles took effect in 1990 and 1991, respectively; these standards are expected to significantly reduce emissions from these vehicle classes as the new models are phased into the vehicle population. However, additional reductions may be needed in Taipei and other urban areas. Alternative fuels-including liquefied petroleum gas (LPG), natural gas, methanol, ethanol, and electricity-represent a promising strategy for achieving these reductions. Vehicle technology for these fuels is being developed rapidly throughout the world.

Possible fuel efficiency improvements of light-duty methanol engines are reviewed in comparison to gasoline engines. This comparison outlines improvements resulting from differences in fuel properties and engine configurations. Methanol engines evaluated included those with higher compression and those using lean-burn, stratified charge. Higher compression yields about a 10 percent improvement over gasoline engines. Lean-burn concepts result in 13 percent increases over gasoline engines operated stoichiometrically. Fuel economy for the California dedicated methanol fleet is evaluated and compared to existing baseline gasoline fuel economy. Data for both carburetted and fuel-injected 1983 Ford Escorts are presented. Fuel economy for the carburetted vehicles used in a variety of fleets ranged from 20.9 to 26.0 mpg on a gasoline equivalent basis.

The California Energy Commission (CEC) and the South Coast Air Quality Management District (SCAQMD) have embarked upon a program to demonstrate the use of methanol in heavy-duty truck application in the state of California. This program is in response to the growing environmental concerns in the major metropolitan areas of California. Methanol engines from five engine manufacturers, Caterpillar, Cummins, DDC, Navistar and Ford will be evaluated in a cross section of applications in public and private fleets. The engines will be used in dump trucks, refuse trucks, beverage delivery, and tractor trailer rigs. The demonstration program will collect data on fuel economy, vehicle performance, vehicle emissions, engine durability and driver response. Several additional methanol fueling facilities will be built at the host sites.

Emission control options for heavy-duty engines are evaluated for meeting the recently promulgated NOX and particulate standards. Particulate options to meet these standards are evaluated in terms of emissions reduction, cost, and cost effectiveness. Control options include particulate trap, clean diesel fuel (low sulfur, low arontatics), methanol, and gasoline. The cost effectiveness for particulate control range from $3,000/ton to over $18,000/ton. These costs, however, are lower than many stationary measures.

American and European technology is being used to demonstrate the suitability of neat methanol as a fuel for transit buses. The project is sponsored by the California Energy Commission (CEC), and transit buses are being operated by the Golden Gate Bridge, Highway and Transportation District (GGTD). Project management and bus testing are performed by Acurex Corporation. Test data are being obtained on performance, fuel consumption, exhaust emissions, noise levels, and operational suitability. One of the coaches was obtained from General Motors Corporation and the other from M.A.N. in Germany. The GM coach employs a Detroit Diesel Allison 6V-92TA two-stroke-cycle engine, which burns methanol by compression ignition. The M.A.N. engine is a spark-assisted diesel, operating on a four-stroke cycle. Both buses are being tested in parallel with diesel-powered counterparts. In comparing diesel with methanol fuel, road performance is nearly identical for each pair of buses.