Transient Engine Testing by Computer Control

This paper describes a computer-controlled engine test cell being developed at the General Motors Research Laboratories. The object is to combine the advantages of the controlled experimental conditions possible in an engine test cell with the dynamic capabilities of a vehicle driven on the road or on a chassis dynamometer to produce a unique research and development tool. The overall system, consisting of an IBM 1800 process control computer linked to an electric dynamometer and engine in an engine test cell, is introduced.

A description is given of the test cell control and data acquisition instrumentation and of the pallet system which permits prebuilding of engine experimental packages for rapid installation in the test cell. An overview of the computer programs, with emphasis on user interaction, is presented. The throttle and speed control algorithms, which apply road or chassis dynamometer load conditions to the engine in the engine test cell, are discussed. Typical engine torque, speed, and exhaust emission results are shown for a 1970 California cycle run on an engine in the test cell.