Abstract: An electronic measurement system for monitoring and measuring indicated horsepower (IHP) of piston type engines which may be spark-ignition, diesel, steam or other power type, based on two or more cycles of operation. Indicated horsepower (IHP) is computed for each engine cylinder in sequential fashion and is based on measurements of cylinder pressure and crankshaft angle of rotation versus time. The system hereof is also operable to measure revolutions per minute of the engine shaft, as well as combustion and compression pressures (just before ignition).

Abstract: A method of measuring temperature utilizing resistance temperature detectors (RTDs) is disclosed. A number of RTDs are sequentially scanned and their resistance values are processed by zeroing and linearizing circuit techniques so that an output signal directly proportional to the temperature of each RTD is obtained. The scanning technique incorporates constant current excitation so that complete linearization of the resistance versus temperature function is made possible with very few high tolerance components.