Numerical and Experimental Investigations of Noise and Vibration Characteristics for a Dual-Motor Hybrid Electric Vehicle

This paper investigates the abnormal noise and vibration of a hybrid electric vehicle during the electric-only driving mode. The sources of the noise and vibration are first identified through the frequency analysis, and then several measures are implemented to reduce the noise and vibration level. The experimental results have identified the gear meshing in the compound planetary gear set is the main source of the noise and vibration. The theoretical analysis demonstrates that gear pairs of the short planet-small sun gear and short planet-long planet in the compound planetary gear set contribute to the main noise and vibration of the hybrid system in the electric-only driving mode. This research also shows that the gear-meshing noise level in the compound planetary gear set can be decreased significantly by matching the engagement parameters, such as meshing stiffness, tooth error, and pitch error. The observation results in this paper are able to provide a practical reference for improving the ride comfort of hybrid electric vehicles in the future study.