Vibration test analysis and powertrain vibration isolation optimization of pure electric bus

Vibration and noise characteristics of powertrain are greatly changed by vehicle electrification to bring new NVH problems, especially, the pure electric bus, as the main means of short distance passenger transport. Here, vibration transmission characteristics and vibration isolation optimization of a pure electric bus were studied based on real vehicle tests and theoretical simulation. Firstly, based on the software LMS Test. lab vibration and noise test platform, vibration signals of key points on the bus floor and chassis were collected to do vibration test analysis. According to vibration response characteristics of the vehicle interior floor, vibration contribution amounts of 18 vibration transfer paths were analyzed, respectively, and the contribution of each transfer path to vibration of the target point in the vehicle was calculated to determine the main contribution path of vibration. Secondly, according to the results of the transmission path analysis, the vibration isolation performance of the key link (Powertrain Mount) on the main contribution path was analyzed. It was shown that the poorer vibration isolation performance of the motor powertrain mounting system is the main reason for excessive vibration in the bus. Therefore, a 6-DOF powertrain optimization model was further established, and the multi-island genetic optimization method was used to do optimization and match design for parameters of the mounting system. Results showed that the mounting system's vibration isolation performance is significantly improved, and the problem of excessive vibration inside the pure electric busis effectively solved. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.