Road Noise Improvement Method for Battery Electric Vehicles Based on Bushing Stiffness Optimization

<div>The chassis bushing is one of the key components affecting the vibration isolation efficiency of a vehicle, and a comprehensive optimization method combining the experimental process and transmission path analysis (TPA) is proposed to reduce the low- and medium-frequency road noise response in the passenger compartment of a battery electric vehicle (BEV). First, the noise signals were obtained in the vehicle road noise test under two working conditions of 40 and 60 km/h at uniform speeds on rough road surfaces. Then, the excitation transmission path was analyzed based on the structural noise transmission model, and the chassis bushing parts with more considerable vibration isolation contribution were screened out. By matching the stiffness values of the chassis bushings in the optimization problem through experimental methods, the optimization scheme reduces the stiffness of the front swing arm bushing and the rear longitudinal arm bushing by 30%. Additionally, a flexible connection is adopted for the rear subframe attachment point, and the tire uniformity parameters are corrected. The results show that the optimization scheme can effectively reduce the road noise response in the low- and medium-frequency bands of BEVs and has been successfully applied to production models in the market.</div>