Design And Performance Analysis Of Exhaust Muffler For Passenger Vehicle

With the rapid development of automobile industry technology, the number of cars in city has been increasing year by year. While bringing convenience to people’s daily life, the automobiles also lead to a series of problems, such as traffic accidents, environmental pollution, noise hazards and so on. The noise caused by car not only affects the comfort of passengers, but also the work efficiency, people’s physical and mental health. Thus it has become one main goal to reduce automobile noise in the auto industry. Automobile exhaust noise accounts for almost a third of the vehicle noise, and the main method of controlling exhaust noise is to install noise elimination devices in the exhaust system. So it can effectively reduce the exhaust noise by designing a kind of muffler with good performance.Firstly, according to the national and enterprise norms, build up test platform of the engine for the exhaust noise as well as back pressure. And set out bench testing of exhaust system without a muffler, record its engine power, torque, shell and stern noise of steady and transient operating conditions. Then establish a one-dimensional pipe model of the engine and exhaust system coupling with GT-Power, and verify the model. Via the comparison and analysis between the calculation results of simulation model and the experimental results of test platform, ensure that the established coupling model can effectively apply to the acoustics and the flow field analysis about the design of engine exhaust muffler.Secondly, by comparing the test data and the enterprise target value, ensure the design goal. Give priority to acoustic performance of main muffler, based on the theory of muffler design, preliminary confirm several structure. And pick out the best solution by comparing the acoustics and flow field performance of different schemes. Carry out orthogonal test for the specific solution, select the optimal parameter combination by statistical analysis on experimental results, ascertain the muffler structure scheme according to one-dimensional simulation analysis. Implement simulated analysis of the airflow speed within muffler, turbulent kinetic energy, temperature and pressure using fluid calculation software Fluent. Enlarge the calculation frequency range of muffler transmission loss with three-dimensional virtual sound field analysis software Virtual.Lab, explore its acoustical characteristics of high frequency.In the light of the conclusion of three-dimensional analysis, put forward the improved scheme and compare it with the original one about sound field and flow field performance. Import the above improved theme into GT-Power, calculate and analyze the stern noise and insert loss. After the indicators meet the design value, carry out the bench test on the muffler sample and get its acoustic characteristics. Compared with straight pipe, gain its acoustic and flow field characteristics. Therefore on the basis of one-dimensional orthogonal design and three-dimensional performance analysis as well as improvement, the design solutions which this paper shows provide reference for the development of muffler.