Research Trumpet-shaped Baffle Car Exhaust Muffler Noise Performance Influence

Automotive exhaust muffler is an important element to reduce automobile exhaust noise. It is very important for vehicle noise control to improve the noise reduction of automobile exhaust muffler. The main part of this article is the research which is about the partition of automotive exhaust muffler. Improving the structure of automobile exhaust muffler can improve the noise performance of the automobile exhaust muffler by changing the shape of the partition.There is only the noise reduction performance of muffler in this study. There isn’t any other performance of muffler. That is to say. there is only the analysis of the transmission loss of muffler.This article summarizes the previous research experience and describes the development history of muffler. This article introduces the composition of the internal combustion engine noise and makes the detailed narration of the composition, characteristics and mechanism of internal combustion engine exhaust noise. At last,it puts forward strategies from the noise source and noise transmission.The research object of this article is the partition of automobile exhaust muffler. According to acoustic theory and the element method, this article shows the working process of the muffler and explores how the trumpet-shaped partition affects the automobile exhaust muffler noise reduction. Get the best noise reduction effect of muffler scheme at last.The original model of this research is Isuzu muffler. Improve the muffler by using a disk type diaphragm to change into a trumpet-shaped partition. Entity model is established by UG and finite element model is established by HyperMesh. And calculate the transmission loss of muffler by SYSNOISE. Then draw the table function curves of transmission loss and compare between groups. At last, the conclusion is that:When the baffle’s opening and air’s intake are in the opposite direction, the transmission loss gets lower, then it increases with the increasing of the angle. When the baffle’s opening and air’s intake are in the same direction, the transmission loss of disc muffler is tower than the trumpet-shaped muffler’s.There is also experiment in this research in addition to software simulation. This experiment is truck accelerated test. The test place and test instruments or equipment are determined with the relevant provisions. Measure the greatest noise of outside of the truck when the truck is speeding up. And compare between groups to the optimal model. The experimental results show that: When the baffle’s opening and air’s intake are in the opposite direction, the maximum noise value outside the truck gets lower, then it increases with the increasing of the angle. When the baffle’s opening and air’s intake are in the same direction, the maximum noise value of disc muffler is lower than the trumpet-shaped muffler’s.The results indicate that the simulation results and experimental results are basically identical:When the baffle’s opening and air’s intake are in the opposite direction, the noise reduction gets better, then it gets worse. When the baffle’s opening and air’s intake are in the same direction, the noise reduction of disc muffler is better than the trumpet-shaped muffler’s.