Acoustic Optimization for Intake System of Commercial Bus

Abstract

Based on simulation and test, a method for engine acoustical source characteristic extraction and acoustic optimization was presented. The intake noise of engine of commercial bus with four different acoustical loads was measured and the characteristic of the noise was extracted using the four-load method. The values of intake noise calculated by BEM were compared with the values measured in the vehicle intake noise test. The comparison result showed that the simulation values agreed with the experimental ones at most of the range which indicated that the extracted result was reliable. The anechoic frequency was determined by analyzing the intake noise spectrum measured in the vehicle intake noise test. Finally, an effective scheme adding a Helmholtz resonator and a quarter wave tube was proposed by simulation, applied to the real vehicle and verified in the test. The acoustic performance of the intake system was improved significantly.