Acoustic Characteristics of Out-of-Phase and Split-Stream Rushing Muffler for Diesel Engine

To solve the problems of poor noise reduction in low-frequency domain and high exhaust resistance of traditional exhaust muffler,a new concept of engine exhaust muffler is proposed based on out-ofphase noise elimination and split-stream rushing.A mathematical model of the muffler for the new concept was established,and the relationship between performance and structural parameters is obtained.Three new mufflers with different parameters were designed and manufactured to test the consideration in a single-cylinder diesel engine.The sound level pressure dB(A),octave-band sound pressure level as well as detailed spectrum of exhaust noise of the tested diesel engine at five different speeds with three mufflers were measured and compared with that without muffler and with original muffler.The correctness of muffler principle is verified.