Research On Performance Optimization Of Vehicle Diesel Exhaust Muffler System

Diesel engine,with its excellent comprehensive performance is widely used in various passenger cars,as the city traffic surge in vehicle exhaust noise becomes one of the main factors of environmental pollution,noise muffler is a major part of the inhibition of sound field transmission,most in finished products have a large optimization space,using computer simulation technology and bench test is an important approach to develop high quality muffler.The design theory,hardware structure,variation law of internal flow field and internal transmission loss of diesel engine resistance muffler were studied in depth,and the multi-objective optimization scheme of target muffler was developed with the help of key technologies of computer joint simulation.The variation law of the internal flow field and the pressure loss under different structural parameters were quantified,and the distribution characteristics of the flow field of the target muffler were calculated on Fluent platform to study the distribution characteristics of the flow field under different structural parameters.In addition,the obtained flow field grid data was imported into the acoustic finite element software Virtual Lab for operation,and the transfer losses of each flow field were analyzed to obtain the sound field transfer losses of the target muffler under the flow field effect.A computer-aided design method that is generally applicable to the resistant muffler was explored through the study.The muffler structure is obtained by using the statistical principle,designing the orthogonal experiment.The results show that the improved muffler has good muffler performance through computer simulation experiment and bench test.Under the same working condition,the average noise value of the improved muffler is 62.49 db,while the average noise value of the original muffler is 67.62 db.The noise value is reduced by 5.13 db,and the reduction rate is increased by 7.5%.Under the working condition of high speed,install the original muffler exhaust noise of mean value is 86.46 d B,install the exhaust muffler noise average after optimization is 80.39 d B,noise value decreased 3.07 d B,decline increased by 7.02%,normal working conditions,installation of the original muffler exhaust noise average is 75.96 d B,install the exhaust muffler noise average after optimization is 69.87 d B,noise value decreased 6.09 d B,a drop by 8.01%.