改善车辆怠速噪声的排气系统结构改进方法

Improvement Method of Exhaust System Structure for Improving Vehicle Idling Noise

针对某防化车排气系统在怠速工况下存在轻微抖动和噪声值偏大的问题,对系统模态进行有限元分析和试验测试研究。根据模态振型分布,采用模态应变能控制、局部振型控制和系统刚度控制3种结构改进方法,并比较了上述3种改进方案的优劣,获得了排气系统模态与发动机怠速激励频率相接近时系统振动过大问题的一般解决方法。通过改进系统局部结构,结合仿真分析结果和实车试验测试结果,表明局部振型控制方法效果显著,能使怠速时的排气噪声下降3.2 d B,解决了原车排气系统怠速噪声过大问题。

For the slight jitter and noise problem of a vehicle exhaust system in the idle condition,the finite element analysis and test research are taken on system mode. The three optimization methods of the modal strain energy,controlling of local mode vibration and system improvement in stiffness are used. Meanwhile their advantages and disadvantages are compared. The general solutions to problems of vibration and noise caused by idling resonance are obtained. Combining the results of simulation analysis and the real vehicle test,it＇s proved that the method of local mode vibration control is most effective,by which the exhaust noise is reduced by 3. 2d B in idle condition among the three kinds optimization. The oversized noise problem of the original vehicle exhaust is solved effectively.