某乘用车车内噪声与方向盘振动分析与改进

Analysis and Improvement of the Excessive Interior Noise and Steering Wheel Vibration of a Passenger Vehicle

对某MPV样车(多功能乘用车)进行整车NVH测试,结果表明怠速工况下空调开启时的车内前排噪声和方向盘振动不满足设计要求。通过传递路径分析方法进行试验排查,发现该工况下,车辆前围板(膨胀阀安装位置)在发动机第4阶频率处振动异常是问题的主要原因。经过进一步验证,确定需对样车前围板进行结构改进。接下来通过有限元分析方法对前围板进行结构仿真优化,并在样车上进行优化后的试验验证。试验结果证实优化方案可行,车内前排噪声和方向盘振动得到有效控制。

In the process of the NVH testing of a MPV(multi-purpose vehicle),it is found that the interior vehiclenoise and the steering wheel vibration cannot meet the design requirements under the idling operation condition with the airconditioner switched on.Through the troubleshooting with transfer path analysis,the dash board abnormal vibration isdetected in the4th order frequency of engine rotational speed at the expansion valve position.It is determined further thatthe dash board needs a structural modification.Afterwards,the finite element method is adopted to optimize the dash boardstructure and the modified dash board is mounted in the vehicle for testing.Results of the test show that the optimizationscheme is feasible and the interior vehicle noise and the steering wheel vibration are controlled effectively.