Analysis And Improvement Of A SUV Intake Noise

The intake noise is the main noise source when engine runs at slow-speeds orduring acceleration. There are a number of embarrassing moments for traditionalparallel and serial connected resonator, due to its feature of low reduction and bigmounting space. Therefore, a new composite silencer combined with air cleaner ispresented for improving noise attenuation in this paper, using resistance andreactance method, which may has significance for improving the comfort and maybenefit for engineering application.Focus on the intake noise of a domestic SUV, the design, simulation andanalysis of intake silencer for noise reduction are investigated in detail as follows.Firstly, the sound attenuation mechanism of air cleaner, quarter-wave tube andtraditional Helmholtz resonator are researched in detail, then the effect ontransmission loss and resonance frequency of them are computed and analyzed byprogramming in software Matlab, based on the theory of plane wave.Secondly, the acoustic performance of Helmholtz resonator is analyzed, thenthree dimensional acoustical finite element model of traditional, parallel and coupledconnected resonators are established, and the calculation equation of transmissionloss is derived based on transfer matrix method and the assumption of plane wave inthe main duct only; acoustic attenuation performance of them are computed,analyzed and comprised, the effect of size parameters on resonance frequency andtransmission loss of Helmholtz resonator is analyzed especially.Finally, acoustic FEM model of the SUV intake system is established, the effectof filter on acoustic performances of silencer is studied, and the passing frequencyand main frequency bandwidth for attenuating noise are fined. Based on the acousticmodel analysis theory, absorbing material is attached on the air cleaner surface ofhigh sound pressure. A new composite silencer consist of optimized air cleaner,quarter-wave tube and coupled Helmholtz resonator is presented according to thetransmission loss characteristic of primitive silencer.The simulation results show that the present coupling resonator is superior tothe traditional serial and parallel connected resonators for noise reduction and thenew composite silencer can significantly reduce the intake noise.