Search Results

Design factors influencing fuel economy include: engine design and size, drivetrain design, vehicle weight, and body size and shape. Data are presented which illustrate some of the basic interactions which occur among these parameters. Relationships between fuel economy and exhaust emissions are also discussed. It is concluded that emission constraints are important and can limit the effectiveness of some design changes to improve fuel economy.

This paper describes the results of a study to evaluate the relationship of compression ratio on fuel energy conservation with the constraint of the 1977 Federal emission standards (1.5 HC, 15.0 CO and 2.0 NOx). The influence of the energy losses in the refinery process to produce higher octane fuels was considered as well as the effect of compression ratio on engine efficiency. Two different emission control systems were evaluated; a catalytic converter-EGR system and a manifold reactor-EGR system. These systems were evaluated on six vehicles; three intermediate size with 350 CID engines at compression ratios of 7.4, 8.3 and 9.2:1 and three sub-compact size with 151 CID engines at the same three compression ratios. Based upon total energy conservation, there does not appear to be an incentive for increasing unleaded or leaded fuel octane levels to allow for the use of higher compression ratios with converter-EGR or reactor-EGR control systems at the 1977 Federal emission standards.

A matrix of cars at three different inertia weights and various displacements were tailored to determine the optimum engine size for best fuel economy within emission and driveability constraints. Two emission standards were considered: 1.5 HC/15 CO/2.0 Nox and .41 HC/3.4 CO/2.0 Nox. The engine size for best fuel economy varied with vehicle inertia weight and emission standard.

A fleet of nearly 250 cars equipped with experimental catalytic converter systems were tested in taxi, police, state, and municipal fleets in various cities throughout the country. This provided a diversified range of customer service and altitude and climatic conditions. The objective was to evaluate the performance and durability in high mileage field service of experimental catalytic emission control systems. The fleet comprised groups of cars with hardware and calibration variations designed toward the 1975 Federal and California and more advanced emission requirements. The converter systems evaluated were primarily a 260 cubic inch underfloor converter and a 140 cubic inch manifold converter. Both bead and monolith substrate catalysts were examined. Test results showed that on the average the systems successfully controlled emissions to below the 1975 Federal and California requirements for greater than 50,000 miles.

The present spark ignition, reciprocating piston, gasoline engine is examined against the basic requirements for an automotive powerplant. The important requirement of emission control is shown to affect these basic requirements. The emission potential of this engine and the prospect of reducing its emissions to an acceptable level are explored. The effect of these factors on future gasoline engines is discussed.

The General Motors Air Injection Reactor System meets the California standards for hydrocarbon and carbon monoxide emission and will be installed on most 1966 GM cars and light trucks sold in California. The various components of the system are described along with their calibration for optimum emission control, and the special techniques used to analyze the system performance on the California Cycle emission test.

A method has been developed to estimate from engineering tests the fuel economy that will be observed by customers in normal car service. Trip length, horsepower, weight, temperature, and type of driving are used to predict customer fuel economy.