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Major technical advances have been introduced in the area of engine controls over the last several years. General Motors has applied many of these product advances including a digital microcomputer to coordinate the major control functions of the engine’s operation: fuel, spark advance, idle speed, EGR, and transmission. Motivation for these advances is based upon maximizing fuel economy and driveability for the customer while achieving effective emission control performance. This paper will provide a description of the systems that have been introduced nationwide in 1981 and 1982 and highlight some of the production activities that were undertaken to ensure quality and reliability.

Systematically reviewed are the fundamentals of Electronic Fuel Management (EFM). Included is a discussion of five EFM areas: 1) air sensing concepts 2) fuel metering concepts 3) fuel delivery to the cylinders 4) fuel preparation with the air 5) calculation hardware (ECM) Presented as a part of the air sensing section is a summary of the physical principles that may be applied to compressible fluid mass air flow rate measurement. Finally, an example of digital computer control of a timed speed density system is reviewed.

Presented is a technical description of the significant features of the General Motors developed Throttle Body Fuel Injection System in production on the 1980 Cadillac Eldorado and Seville passenger cars. TBI fuel system discussion is divided into the 69 kPa (10 psi) fuel system, injector performance, fuel pump, sensors, electronic control module and system fuel control philosophy based upon speed density. Since achievement of low operating pressure for the fuel injection system is a significant technical accomplishment, the TBI fuel system design to accommodate hot fuel conditions will be reviewed.

The use of a laboratory simulator to evaluate the performance of wheel slip control systems under controlled operating conditions is reported. It is shown how an analog computer can be interconnected with a hydraulic brake system and wheel slip control hardware to form a hybrid simulation of a vehicle installation. An analog computer can also be used to simulate vehicle dynamics and tire-to-road friction characteristics. Simulator accuracy is established by correlating laboratory results with road data. Advantages and disadvantages of using the simulator in lieu of experimental road testing are pointed out.