Formulation of a numerical simulation, accounting for the pressure fluctuation phenomena in an intake pipe of a 4-stroke, 4-cylinder engine, was the objective of the current study, which should deliver an efficient prediction on the volumetric efficiency, a key factor to the engine power. Engine tests were performed to find out the boundary conditions of the computer simulation, to compare and confirm several published data and finally to evaluate the accuracy of the program for cases of various engine loads and speeds: The pressure pulsation data obtained from the computer simulation gave better prediction at low speed and load conditions, providing the volumetric efficiency within about 5% accuracy. It was clear that there was relatively more room for improvement in the program on the exhaust side than the intake part. Nevertheless, the relatively large inaccuracy occurred in the exhaust pipe did not give a serious influence on the prediction of the volumetric efficiency.
