Research On NVH Performance Optimization Of Automobile Intake System

According to relevant statistics,traffic noise accounts for 75% of urban noise pollution,and automobile noise is the main source of noise contribution.With the continuous advancement of automobile technology,More and more attention has been paid to the performance of vehicle N VH.Automobile engine noise,tire noise,exhaust noise,etc.are gradually being effectively controlled,which makes the influence of intake noise on vehicle NVH is getting more and more attention.Taking a passenger car in the late stage of development as the test object,troubleshoot NVH problems such as venting sounds and high interior noise caused by the intake system.Perform an accelerated test on the acoustic hub,the noise source is identified by the exclusion method and the modal analysis method.It is found through experiments that the cavity does not play the sound elimination function,the air filter is insufficient in rigidity,and its own mode induces the acoustic-vibration coupling resonance.After optimizing the resonant cavity and the air filter,the noise of the intake nozzle is reduced to some extent,but the noise in the vehicle is basically not improved.The transmission path method is used to analyze the interior noise caused by the excitation of the vehicle intake system.It is found that the vibration of the intake pipe was transmitted to the vehicle and caused the peak of the noise inside the vehicle.After the vibration reduction treatment,the peak of the interior noise was improved.The noise reduction effect of the fiber fabric tube and the broadband silencer was evaluated through experiments,the test results show that the air leakage sound of the intake pipe and the interior noise are obviously improved,however,the frequency cancel ation performance of the broadband muffler is not good.The choice of optimization algorithm directly determines the efficiency of the operation and the quality of the optimization results,compare the advantages and disadvantages of common optimization algorithms,established the optimization objective function,and propose two optimization schemes,the simulated annealing algorithm,genetic algorithm and adaptive genetic algorithm are used to optimize the silencer.The results show that the simulated annealing algorithm can get a better solution under the condition of good efficiency.Genetic algorithm needs multiple operations to adjust to the appropriate parameters,the computational efficiency is slightly worse than the simulated annealing algorithm.In theory,the quality of the solution obtained by the adaptive genetic algorithm is higher than that of the genetic algorithm,but it also needs to set the appropriate parameters,and its computational efficiency is too low,and the engineering application has no advantage.Traditional silencers are usually designed by experience and have poor noise cancellation performance.The transfer matrix method is used to derive the formula for calculating the transmission loss of multi-cavity perforated pipe muffler,the simulated annealing algorithm is used to optimize the structural parameters of the perforated silencer.The muffler acoustic model is established by the obtained structural parameters,the acoustic finite element simulation is carried out in Virtual.lab.Finally,the double load method is used for experimental analysis.the test shows that the silencer has better acoustic characteristics in the optimized frequency band.