| With the rapid development of automobile industry and transportation industry, people have more and more dependence on cars, thus car ownership in China greatly is increasing year by year. Now many cities are faced with more pressure and challenges on car noise control, at the same time, people have higher requirement in automobile comfort. There are many factors for noise produced by cars, but the engine exhaust noise produced by cars is about30%of the proportion in the whole noise. When people due with the engine exhaust noise, controlling the reduction of noise from the source noise is very limited. Therefore, the simplest and most effective noise reduction measures are to install the exhaust muffler in the engine exhaust system. Good mufflers can reduce the exhaust noise, on the other hand, on the other hand engine power loss should also be low. Traditionally, the test method in the study of muffler is an important means by automobile noise researchers, however, limited by test cost as well as the experimental study on a long cycle, these factors brought a lot of inconvenience for researchers. With the development of the computer and the further application of simulation technology in automobile, GT-POWER in the simulation calculation of motor performance has been widely used, a lot of practices has proved that using GT-POWER in muffler design has high reliability, the early stage of the muffler design and development,to a certain extent, can replace experimental study.In this paper, using GT-POWER software to build a model of a six-cylinder turbocharged engine and verify the exactness of the model of the engine power performance. Noise is analyzed in some rotating speeds of engine often used, the1/3octave, each order and tail pipe overall noise figure are analyzed, probe into its exhaust noise acoustic properties. According to the muffler design principles, through establishment and improvement from optimization, selecting1exhaust muffler, the scheme based on improved1, designing two different types of mufflers through improvement, coupling engine model to evaluate the performance of muffler noise reduction. Building transmission loss, insertion loss and pressure loss, analyzing the comparative study among3different types of mufflers. At the same time considering multiple factors, internal structure was reformed according to the simulation result of scheme1, and through the simulation calculation for the muffler to adjust the internal structure, establishing the principle of internal structure optimation. Finally, in consideration of the premise of noise reduction and the pressure loss, the simulation results show that the solution3is the best one in the overall effect, kinds of performances can all meet the request of the customer. |
