Study on Performance of Automobiles Muffler Based on Sound Transfer Matrix Theory

摘要

According to the characteristics of automobiles exhaust noise of high pressure level and middle-low frequency, combining sound transfer matrix theory and FEM-Fluid analysis method, simulations of the transmission loss with non-insertion tube expansion chamber muffler, single insertion tube expansion chamber muffler and dual insertion tube expansion chamber muffler are carried out, which obtain the transmission loss curves of mufflers in different structures and different perforation rates. The results show that the max transmission loss and the average transmission loss of the muffler with perforation rate of 5% are greater than that of 3% and 10% below the low frequency of 200 Hz; dual insertion tube expansion chamber muffler not only can increase the transmission loss below the frequency of 4000 Hz, but also can effectively improve the performance of the mufflers in which have non-perforation tube and single insertion tube at some frequency points. The results of research can provide technical reference for exhaust muffler design of automotive.