Abstract：Aiming at an idle abnormal noise of a middle-duty truck, several approaches, such as, spectral analysismethod, acoustics interaction filter, selective sound intersitymethod for surface source identification and physical separation ofnoise source base on expunctionmethodwere used to identifynoise source and rereal its spread and radiationmechanism. Analysis showed that the frequency range of the idle abnormal noise is from 274Hz to 330Hz; the air intake and the air cleaner shell of the intake system are the surface noise sources; while the intake noise of the air compressor is the essentialnoise source; the edle abnormalnoise can be eliminated bymodifying the intake system of the air compressor.
2009, Vol. 28 
