The paper discusses the interior NVH problems caused by the exhaust system. It is found that the booming noise inside a vehicle at 3900 r/min rotational speed is caused by the exhaust structural vibration. The exhaust system modal parameters are identified by experimental modal analysis and finite element analysis, respectively, and the booming is found to be caused by the modal coupling effect of the hot end and the cold end of the exhaust system. The system is optimized by finite element analysis. A reinforced bracket between exhaust manifold and engine body is added and ball joint position at the cold end is adjusted and optimal results are obtained. Eventually, the test shows that the booming noise is significantly reduced.%阐述排气系统引起的车内NVH问题.通过运用排气系统振动噪声分离手段,得出某样车3900 r/min轰鸣噪声是排气系统结构噪声引起的.分别应用试验模态分析和有限元模态分析技术对排气系统模态参数进行识别,发现该轰鸣声是由于排气系统热端和冷端模态耦合引起.同时应用有限元模态分析技术对该问题进行优化分析,得出在排气歧管和发动机缸体之间增加加强支架和更改排气系统冷端球绞位置的方案.最后通过试验验证,该方案能够很好的解决车内轰鸣噪声问题.
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