某乘用车排气系统异响噪声分析和方案优化

Abnormal Noise Analysis and Plan Optimization of a Passenger Car's Exhaust System

针对某乘用车怠速时出现的异常噪声,采用听诊器、消去法以及频谱分析技术,锁定了异响声源,结果表明排气系统前消声器附件存在183 Hz的共振,吊钩的振动被放大,辐射噪声。提出了吊钩位置前移和排气系统管壁减薄方案,并对方案进行实车验证,结果表明,两个方案都能有效的解决异响问题,综合考虑选择排气系统管壁减薄方案,其有利于车辆的轻量化,并对整车的加速噪声无影响,且能降低后排的发动机4阶噪声。

Aiming at the abnormal noise that appears when a passenger car is idling,the stethoscope,elimination method and spectrum analysis technology have locked the source of the abnormal sound.The result shows that the front muffler attachment of the exhaust system resonates purely at 183 Hz,and the vibration of the hook is amplified and radiated noise.Proposed the plan of hook position forward and exhaust system pipe wall thinning,and verified the plan in real vehicle.The results show that the two schemes can effectively solve the abnormal noise problem,and comprehensive consideration is given to the choice of exhaust system pipe wall thinning.The solution is beneficial to the weight reduction of the vehicle,has no effect on the acceleration noise of the entire vehicle,and can reduce the fourth-order noise of the engine in the rear row.