Evaluation of methodology for determination of mechanical efficiency of spark ignition engine

Abstract

Measurement of total friction of the internal combustion engine typically requires accurate, crank angle resolved measurement of the cylinder pressure and simultaneous measurement of the brake torque. Instrumentation complexity and expenses limit such measurements to scientific research domain. Simplified commercial research or educational work require less expensive and less time consuming methods. Alternative method for engine friction measurement, Morse test, requires only measurement of the brake torque and engine speed. The results of the experimental measurement of the engine friction, obtained by indicated pressure analysis and Morse test are compared and discussed. The Morse test was found to be a sufficiently accurate method for friction measurement at low load conditions.