某客车噪声故障分析及优化

针对某客车的噪声异常问题,通过试验,查找并确定故障源,分析故障产生机理并进行优化。噪声异常客车驾驶室存在怠速拍频,原因为空气压缩机1.12阶次与发动机曲轴1.00阶次能量干涉,导致振动、噪声异常,舒适度降低;客车内存在显著打鼓声,原因为进气系统设计不合理及空压机激励大,导致的进气系统声腔共振。通过更换离合器降低1.00阶次异常振动,消除了室内拍频;通过增加进气消音器,降低了激励源的能量,消除了打鼓声。优化后进行试验验证,整车噪声、振动、声振粗糙度(noise,vibration,harshness,NVH)水平得到明显提升,主观感受整车舒适性得到极大改善,为同类NVH问题的解决提供了参考。

Noise fault analysis and optimization of a bus

Aiming at the abnormal noise problem of a bus,the fault source is found and determined by the test method,and the mechanism of the fault is analyzed.Indoor idle beat frequency is analyzed as energy interference of 1.12 harmonic frequency of air compressor and 1.00 harmonic frequency of engine crankshaft,which leads to abnormal vibration and noise and makes people feel uncomfortable.There is a significant“drumming”sound inside the vehicle.The analysis shows that the sound cavity resonance of the air intake system is caused by unreasonable design of the air intake system and large excitation of the air compressor.The indoor beat frequency problem is eliminated by replacing the clutch to reduce 1.00 order abnormal vibration,and the energy of an excitation source is reduced by adding an air intake silencer.After optimization,the test shows that the NVH level of the vehicle is obviously improved and the subjective comfort of the vehicle is greatly improved,which provides a reference for the solution of similar NVH problems.