Prediction of Excitation Forces and Powerplant Vibration in a Horizontally Opposed Engine

A useful analysis method of excitation forces and powerplant vibration caused by engine operations has been developed, intended for a powerplant which consists of a horizontally opposed 4-cylinder engine and a longitudinally mounted transmission. The developed method uses a commercial mechanical dynamics solver to calculate the excitation forces which involve the effects of crankshaft vibration and main journal clearances. Also a vibration analysis model of the powerplant is built using the results of experimental modal analysis, for the prediction of powerplant vibration levels. The calculated result was verified by the measured vibration data, and it was confirmed that this analysis method can predict the low order components of powerplant vibration with reasonable accuracy.