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The need for expert systems in the Heavy Truck and Bus Industry is rapidly approaching a critical point in time. This time reference is the revised emission standards and requirements for heavy duty diesels. This need is related to the influx of electronically controlled engines and their companion the electronically controlled transmission as well as the present shortage of skilled mechanics. This paper discusses the conceptual approach and reasons that expert systems are well suited as a diagnostic aid for vehicular repair. This paper also discusses the implementation of a commercially available expert system for the diagnosis of class 7 and 8 vehicles. The body of this paper will be divided into four discussions. First, applicability of AI/KB programs used for vehicle diagnostics. Second, the use of expert systems to diagnose electronically controlled power modules and their related interactivities with the vehicle.

Through the clean air act and other various federal and state legislation, fleets are facing greater pressures to use alternate fuels. This is not because alternate fuels are so desireable, but that they are potentially the fuels, used with recent engine developments, which can meet the future emission standards of the E.P.A.. These alternates are: liquified natural gas, compressed natural gas, methanol and ethanol. Currently there is no national or local publically available infrastructure system for the distribution of these fuels. Despite the weakness in the infrastructure system, alternate fuel usage seems certain to grow in the future. This paper will outline two micro-tests conducted in Chicago using biodiesel as an alternate fuel for in-service motorcoaches. This was an exploratory investigation to determine the effects of the fuel on the engine, the performance characteristics and the infrastructure requirements needed to use this fuel.

The subject of alternate fuels has been addressed for the past 20 years in an effort to solve emissions and world fuel supply concerns. A recent study of the available literature and technology to date pointed out a need for a single source of information for the fleet operator. This paper will be divided into discussions of emissions requirements, world fuel supplies, alternate fuel options and the technical concerns to the fleet operator.

Emission standards derived to protect the environment have driven engine manufacturers to accelerate their efforts in engine emission development in order to meet the mandated standards. This paper will outline the current and upcoming emission standards, the technology involved in accomplishing the requirements and the solutions to in-service engines meeting their emission standards. The paper targets the fleet operator to provide a single source of information in an effort to alert them to upcoming requirements and what can be expected when specifying equipment for procurement. The technology discussed in this paper varies in its application for several engine makes and models. Since technology transfers from application to application it is vital that these ideas and concepts be explained.

For over a decade engine manufacturers have been pursuing alternative fuel strategies for vehicle powertrains. First came the discussion of fuel selection. Next, whether or not these alternative fuels can provide the utility offered by traditional diesel. Finally, the footrace of technology and hardware to provide utility, reliability and maintainability with the use of alternative fuels. Now the day has come where many alternative fuels are a practical reality. The body of this paper will discuss the utilization of natural gas as an alternative fuel. This paper targets the fleet operator in an effort to provide a single source of information in a concise format. A discussion of emission standards, engine operational strategies, component technology, fuel characteristics and the utility of using natural gas as a fuel will be addressed. The understanding of present and future engine development is of great importance to a successful fleet operation.

In July, 1992 The Environmental Protection Agency (EPA) issued its final rule of section 604 of the Clean Air Act Amendments of 1990. The rule limits the usage, production and servicing of air-conditioning systems using CFC-12 (R-12) and HCFC-22 (R-22) refrigerants. The purpose of this action is to limit the deterioration of the stratospheric ozone layer. The reduction of the ozone allows ultraviolet radiation, type-B (UV-B), to penetrate and project down onto the earth. The act will affect the fleet operator in ways that may not have yet been explored. Specifically, operators will be faced with spending thousands of dollars on technology, as an industry and as individuals, to facilitate the necessary air-conditioning system conversions to provide compliance with the law and comfort for passengers. The need to develop an acceptable R-12 retrofit program has become a reality. This paper will outline the techniques for a successful R-12 to R-134a refrigerant conversion.