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Currently, several cost-per-mile calculators exist that can provide estimates of acquisition and operating costs for consumers and fleets. However, these calculators are limited in their ability to determine the difference in cost per mile for consumer versus fleet ownership, to calculate the costs beyond one ownership period, to show the sensitivity of the cost per mile to the annual vehicle miles traveled (VMT), and to estimate future increases in operating and ownership costs. Oftentimes, these tools apply a constant percentage increase over the time period of vehicle operation, or in some cases, no increase in direct costs at all over time. A more accurate cost-per-mile calculator has been developed that allows the user to analyze these costs for both consumers and fleets. Operating costs included in the calculation tool include fuel, maintenance, tires, and repairs; ownership costs include insurance, registration, taxes and fees, depreciation, financing, and tax credits.

A 1979 8V-71 model DDC two-stroke diesel transit bus engine was tested using ignition-improved methanol and ethanol. The testing was conducted using the Environmental Protection Agency heavy duty engine transient test procedure. The methanol and ethanol fuels were found to have very similar combustion characteristics and required the same percentage of ignition improver (7.5 volume percent) to obtain similar peak cylinder pressures and rates of pressure rise as were observed using diesel fuel. Emissions increased rapidly as the percentage of ignition improver was reduced below the optimum determined. Ignition-improved methanol and ethanol can greatly reduce fuel-produced particulate emissions with the trade-off of a small increase in total unburned fuel emissions. Carbon monoxide emissions were found to be dependent on stoichiometry only and not fuel type.

A study was conducted to determine the feasibility, performance, and emissions of a Detroit Diesel Corporation 8V-71 transit bus engine using ignition-improved methanol as fuel. Major objectives to be achieved by the study were: 1) to determine the minimum amount of ignition improver required for acceptable engine operation; and 2) to compare the exhaust emissions with ignition-improver methanol to emissions with diesel fuel. The engine was tested for emissions using the transient and 13-mode emission procedures and for smoke using the Federal smoke test. In addition to measurement of regulated emissions and smoke, cylinder pressure traces were obtained and compared with pressure traces from operation on diesel fuel. Minimum modifications were made to the engine in adapting it for operation on the methanol/additive mixture.

Advanced gas turbine (AGT) engines may exhibit widened fuel tolerance as well as improved thermal efficiency relative to current spark-ignition engines. However, the inherent adaptability of the engine to a variety of fuels may not be reflected in the practical fuels adaptability of gas turbine engine vehicles which are acceptable from commercial and regulatory perspectives. This paper presents the results of a study of the primary issues surrounding the fuels adaptability of commercial AGT vehicles. Topics addressed include candidate fuels and fuel characteristics, and AGT combustion and fuel system characteristics. Results of an analysis of relationships between engine characteristics and fuel properties are presented as well as observations concerning future research.

The concept of using alcohol fuels as alternatives to diesel fuel in diesel engines is a recent one. The scarcity of transportation petroleum fuels which developed in the early 1970's spurred many efforts to find alternatives. Alcohols were quickly recognized as prime candidates to displace or replace high octane petroleum fuels. However, alternatives to the large demand for diesel fuel in many countries were not as evident. Innovative thinking led to various techniques by which alcohol fuels can partially or completely displace diesel fuel in diesel transportation vehicles. The methods of using alcohol fuels in diesel engines (in order of increasing diesel fuel displacement) include solutions, emulsions, fumigation, dual injection, spark ignition, and ignition improvers. Power output, thermal efficiency and exhaust emissions can change significantly depending on the techniques employed. Reliability and durability still need to be demonstrated for most of these techniques.

With more and more fleet vehicles being converted to compressed natural gas operation, concerns have arisen about the safety of their fuel systems and the need for regulations to ensure safe operation. The potential for widespread operation of vehicles using compressed natural gas adds urgency to these concerns. Most of the safety concerns revolve around the high-pressure storage and fuel lines present in existing systems. Specific items in question are: the need for high-pressure automatic fuel cutoff switches, vehicle disablement during refueling, the need for methane sensors, cylinder specifications and venting requirements, location of refueling points, and system crash-worthiness. This paper examines these concerns.

Natural gas provides a current, low-cost alternative to the use of gasoline and diesel fuel for highway transportation vehicles. However, due to the capital costs required to use natural gas as a transportation fuel in either compressed (CNG) or liquefied (LNG) forms, some applications are more advantageous than others. Generally, fleets provide the best opportunity for conversion because of the sheer volume of fuel required and because most vehicles return to a single location each day. The advent of small compressors may make conversion to natural gas feasible for private individuals. Presently, the most popular conversions are to CNG due to the limited availability of liquefiers to produce LNG.

The direct utilization of minimally processed solid fuels (particularly coal) in transportation engines is assessed. Both highway and non-highway applications are considered. In general, solid fuels do not seem appropriate for highway transportation in the 1980-2000 time frame. Such fuels can be utilized for non-highway transportation with some engine types. Both technical and environmental issues are explored and a systems approach for studying the topical area is stressed. The paper features a brief historic review and current update on activities in the area of direct solid fuels utilization in transportation engines.