A Study of Reducing the Contribution of a Diesel Engine 1st Order Excitation for Vehicle Noise and Vibration

For 4-cylinder 4-stroke engine, the main low order excitation comes from its 2nd order excitation. But there is still a big 1st order excitation besides the 2nd order excitation caused by combustion characteristics and the vibration intensity of the diesel engine, which results in isolation performance does not meet our expectations. Because of design and process, above phenomenon is more common in the domestic engine. This paper presents a new mount design idea, which is to both reduce the impact from the road and the 1st order excitation via matching the relationship among mount system loss angle, 1st order excitation and road impact. The new design hydraulic mount has been used in an upcoming MPV, which significantly increase isolation of mounting system performance and reduce noise and vibration inside the MPV.