Study On The Simulation And Testing Method Of Engine's Exhaust Noise

It is very important to research and test the intake noise and exhaust noise of engine because they are main noise resources of automobile.Based on the specifics of the gasoline engine researched in this paper an engine model has been established by using GT-Power software, in which the sub-models of intake system, exhaust system, air cleaner, mufflers and combustion are fine enough. The comparison of the performance results respectively from test and simulation shows that the engine model is accurate.Two methods have been applied to measure the exhaust noise of the engine. One is to measure the exhaust noise directly. The other one is to calculate the exhaust noise by the background noise and total noise measurements. An acoustic enclosure is applied in the testing and its insert loss is larger than 10 dB(A), which satisfies the testing requirement.The measurement shows that, with engine speed increasing the exhaust noise becomes stronger and the middle to high frequency noise increases more rapidly than low frequency noise. The exhaust noise and combustion noise and machine noise are coherent. The exhaust noise is one of main noise resources of engine, so it is effect for engine noise reduction to reduce the exhaust noise, especially when the engine working at high speed.The engine model established in this paper for exhaust noise prediction is accurate.