A versatile electronic engine indicator

Knowledge of the working pressures within the cylinder of an internal combustion engine is of great importance in engine development work. An outline of the history of devices for obtaining this information is given, followed by the requirements for a satisfactory indicator. The principles of operation, con struction and temperature sensitivity of a number of different types of transducers are discussed and examples described. A trolley-mounted cathode-ray engine indicator is described which is arranged in a novel layout for use with several types of transducers. Details are supplied of the pre-amplifiers and pre-circuits employed and special consideration is given to facilities for time or crank-angle sweep, crank-angle marking, beam blanking and photography. The practical operation of the indicator is outlined in order to illustrate how a wide range of measurements can be made.