The exhaust noise contains complex noise elements , including the exhaust noise with a base frequency measured in the number of exhausts in unit time , the resonance noise of the gas column in the pipe , the gas stream blowing noise at the exhaust manifold , the exhaust gas jetting and impact noise , the helmholtz resonance noise of the cylinder , the karman eddy noise and the turbulent noise inside the exhaust system 排气噪声包含了复杂的噪声成分：以单位时间内排气次数为基频的排气噪声、管道内气柱共振噪声、排气歧管处的气流吹气噪声、废气喷注和冲击噪声、汽缸的亥姆霍兹共振噪声、卡门涡流噪声及排气系统内部的湍流噪声等。
