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The importance of the fuel in providing improved vehicle performance and reduced emissions has become widely recognized in the past ten years. However, few if any systematic analyses of gasoline quality have ever been published. A methodology has been developed for analyzing the vehicle performance and emissions characteristics of gasolines. It has been applied to data obtained from surveys of United States' service station gasoline samples obtained in 23 cities during 1996. Results are presented for: gasoline type (California RFG - reformulated gasoline, Federal RFG, low RVP - Reid Vapor Pressure, and conventional); gasoline grade (regular, intermediate and premium); individual cities; individual brands (coded); and for sulfur content, the fuel property with the greatest current interest. It is concluded that large differences exist among commercial gasolines for all of the items evaluated.

Although exhaust gas odorants are generally a product of engine and fuel parameters, it is the vehicle that the public associates with exhaust odor. The vehicle and its movements have a large influence on the dispersion of exhaust odorants and, therefore, on the actual public exposure to exhaust odor. A considerable amount of public exposure to vehicle exhaust odor results from municipal operation of diesel-powered buses, especially during the bus-stop sequence. Panel test procedures were developed for field evaluation of full-scale vehicle exhaust odor intensity during the idle and acceleration portions of a simulated bus-stop sequence. Odor tests, based on natural dilution of the vehicle exhaust to the odor threshold, were conducted in a controlled environment, indoors in large buildings. Different degrees of exhaust dilution were achieved by randomly varying the distance from the test vehicle to the panelists.

Emission rates of benzene-soluble matter (tar), benzo (a) pyrene (BaP), and benz (a) anthracene (BaA) were determined for gasoline engines and automobiles in simulated city driving, and for a diesel engine in simulated city bus operation. A study of the effects of operating conditions and fuel factors indicated that for minimum exhaust emission of polynuclear aromatic hydrocarbons, engines should be operated with minimum lubricating oil in the combustion chamber or exhaust system, maximum air/fuel ratio, and minimum aromatics (especially polynuclear aromatics) in the fuel. On a concentration basis, emissions of BaP and BaA from gasoline engines were greatest during decelerations, and on a mass emission basis were greatest during accelerations. For a group of 25 cars, the average BaP emission rates were 6.6 ug/M3 exhaust or 169 ug/gal gasoline. BaA concentrations were approximately four times higher. Tar emission was approximately 0.2 gm/mile.

The importance of the fuel in providing improved vehicle performance and reduced emissions has become widely recognized, especially in the past ten years. In 1998, an SAE paper was presented providing a systematic analyses of 1996 United States gasoline quality. This paper extends the methodology of that paper to include the impact of fuel composition on evaporative emissions, and it provides analyses of gasoline quality for the years of 1996, 1997 and 1998. The vehicle performance and emissions characteristics of gasolines were determined using data from surveys of United States' service station gasoline samples. Results are presented for: gasoline type (California RFG - reformulated gasoline, Federal RFG, low RVP - Reid Vapor Pressure, and conventional); gasoline grade (regular, intermediate and premium); individual cities; individual brands (coded); and for sulfur content.

This paper summarizes the history and most significant accomplishments of the GMR-GMR&D Fuels and Lubricants Department from its predecessor organization starting about 100 years ago to its demise during a reorganization in the late 1990s. It covers: Combustion research to improve engine efficiency and reduce emissions, Development of chemical, bench, engine, and vehicle tests to improve fuel and lubricant quality, Development of technology to reduce vehicle emissions, Research to understand and reduce air pollution, and Evaluation of alternative fuels and lubricants. In total, the above activities helped not only GM and the worldwide auto industry, but also society. They improved the operation of vehicles and the quality of the air in the United States and around the globe, favorably affecting the lives of hundreds of millions of people. They also created the recognition of and the reputation of the Fuels and Lubricants Department as the best of its kind in the world.