客车排气系统振动特性分析及悬挂位置优化

Vibration Characteristic Analysis and Hanger Location Optimization of Bus Exhaust Systems

排气系统的振动与噪声是影响整车NVH水平的重要因素,良好的排气系统悬挂点布置及刚度匹配能够有效的降低排气系统与车体之间的振动能量传递。采用Hyperworks软件对某增程式电动客车的排气系统进行有限元建模,同时依据有限元理论对此排气系统进行静平衡分析和模态分析;通过静平衡分析获得悬挂的变形量,通过模态分析得到排气系统的固有频率及振型,依据平均驱动自由度理论,获得排气系统悬挂点的理论最优布置方案,并对分析结果进行评估,为排气系统悬挂吊耳刚度及位置的选择提供技术依据。

Noise and vibration of exhaust systems have a great impact on NVH performance of vehicles. Optimal hanger locations and stiffness of the exhaust systems can effectively reduce the vibration energy transfer between the exhaust system and the vehicle’s body. In this paper, the software Hyperworks was applied to establish the finite element model for an Extended-Range electric bus’s exhaust system. Based on the finite element theory, the modal analysis and static equilibrium analysis were completed. The hanger’s deformation was calculated by the static equilibrium analysis, while the natural frequencies and modal shapes were obtained by the modal analysis. According to the average driving DOF displacement theory, the theoretical optimal solution of the hanger’s location was obtained. Result of the analysis was evaluated. This work provides an effective technical basis for the selection of hanger’s stiffness and location.