Experimental Research On Intake System Noise And Orthogonal Design Optimization

With the improvement of people’s living standards, global automotive industry is developing rapidly and the car ownership increase constantly. Along with it come noise pollutions, environmental issues, energy consumption and other issues. The demand of seeking comfortable car performance is more and more intense at the moment. One of the main methods to reduce noise is to constraint the engine intake noise effectively. And many countries are beginning to draw restrict regulations on engine intake noise. But the structural parameters of intake silencer elements are numerous, which not only influence the noise elimination performance, but also affect the performance of engine. Therefore, how to efficiently matching silencer elements become the emphasis and difficulty in the premise of ensuring silencing capacity and engine performance. According to the characteristics of engine intake noise emission, the design method of orthogonal test is put up forward to optimize and improve the intake muffler.Firstly, the mechanism of intake noise is analyzed. The categories of silencer are described. It is pointed out that reactive muffler should be applied in engine intake system to decrease intake noise, according to the frequency characteristics of intake noise. But because the silencer element anechoic performance is great affected by its structure parameters and the performance of engine would decline if it changes slightly. So the intake pressure loss of intake system is used as the standard of the reasonable selection of intake mufflers.Secondly, the engine model matched the bench test is established in GT-Power software and the intake noise is simulated, furthermore the frequency band corresponding noise cusp is obtained. The paper presents the optimization and improvement direction of the engine intake muffler elements by analyzing the pressure loss of original engine intake system and the performance of air filter on flow field characteristics and acoustic properties.Intake silencer elements are applied in this paper which mainly includes air filter, Helmholtz resonator and quarter wave length pipe. And their acoustic properties can be detailed analysis by using Virtual.lab software. Several groups of intake silencer elements’ parameters can be initially identified by use transmission loss. The above parameters are quickly shaped by orthogonal design by taking the insertion loss of intake silencer elements as the text index, which reduce the number of test numbers and improve the design efficiency of the intake silencer elements. Furthermore under the condition that intake pressure loss is less than 3kPa, the paper analysis the intake silencers’ installation by Fluent software targeted the pressure loss. And it is shown that the scheme cannot only meet the requirements of the intake noise, but also the impaction of engine power is within the scope of the project license by analyzing and verifying the determined silencer elements.