The Numerical Simulation Research On Acoustic Performance Of Exhaust Muffler Of Automotive

The exhaust noise of automotive engine is one of main noise sources of automobile noise. The most effective measure to control exhaust noise is using muffler in exhaust system. Designing a muffler with high anechoic performance and low resistance loss has become an important subject on exhaust noise control.Complicated muffler was composed by a number of noise basic structure. Using one-dimensional fluid dynamics software GT-Power to numerical simulated and analysed reactive muffler basic structure and its parameters. After discussed the effect of muffler anechoic performance such as resistive muffler unit, the existence of inserted tube muffler unit, insert a tube bias of muffler unit, the existence of straight-through perforated pipe muffler unit and so on. Then focused analysis on the structural parameters on the muffler performance of noise, such as the expansion proportion, expansion chamber length, numbers of expansion chamber, perforated baffle, inserted pipe, pipe offset, perforated pipe and other properties, which affected to the anechoic performance of the reactive muffler was nailed down.Based on the muffler design and improve theory and principles, calculated 4JB1 diesel engine exhaust muffler transmission loss, according to the weak point of muffler performance, two plans were taken to design and improve muffler structure. Through software simulation results show that plan A has made the muffler performance greatly improved.The numerical simulation of exhaust muffler in this thesis can provide reference and new method for muffler design. It is of important instructional significance for improving the design and analysis of muffler.