Noise Analysis And Muffler Design Of Intake And Exhaust System Of A Vehicle

With the popularization of automobile,the competition of automobile market is becoming more and more big,people also pay more and more attention to the comfort of automobile,vibration and noise is an important index to evaluate the comfort of an automobile.The research object of this paper is a certain model of SUV(Sports Utility Vehicle).Noise analysis is conducted on the intake system turbocharger and exhaust system,and finite element acoustic analysis is conducted to design and optimize the muffler.The main work is as followsFirstly,the slight surge noise of turbochargers is studied.When turbochargers work,the acceleration process of vehicles is accompanied by"hiss" sound,and there is obvious ear pressure sensation.The subjective experience of drivers is poor.The noise level of turbocharger near field and driver's inner ear was tested by road test.The results show that the main noise frequency band is between 700-1600Hz.After analysis,it can be determined that the turbocharger has a slight surge.The corresponding muffler is designed based on the finite element analysis,and the transmission loss of the muffler is calculated.The results show that the transmission loss of the muffler in the 700-1600Hz frequency band was more than lOdB.finally,a real car test is carried out,and the slight surge noise in the car was obviously improved after the muffler is installedThen,the interior acceleration noise is studied.In the process of acceleration,the car is accompanied by obvious roar,and the subj ective experience of the driver is poor The noise in driver's inner ear is tested by road test,and the exhaust system was identified as the noise source by means of noise source identification.According to the calculation,the noise is 42Hz low frequency noise.The corresponding muffler was improved based on the finite element analysis,and the transmission loss of the muffler was calculated.The results showed that the transmission loss of the muffler reached 20dB at 42Hz.Finally,a real car test was carried out.After the muffler was replaced,the interior noise disappearedFinally,in order to examine the influence of the optimized muffler on the structure and performance of the exhaust system,static analysis and modal analysis are carried out on the optimized exhaust system.The results showed that the stress and strain of the exhaust system increased slightly after optimization,the strength and stiffness were in line with the design requirements,and there was almost no significant difference in the natural frequency and vibration mode of the exhaust system,and the suspension point position of the exhaust system was determined according to ADDOFD(Average Driving DOF Displacement).