某新车型怠速噪声严重超标，通过仿真软件 GT-Power 和 Fluent 仿真分析明确了 消声器低频消声不足的原因及结构缺陷． 提出了横流穿孔结构的前消声器结构，并改进了 主消声器的穿孔形式． GT-Power 仿真和试验结果表明，消声器低频消声性能得到提高，无 载和带载怠速噪声分别降低超过4dB( A) 和3dB( A) ，三挡全油门尾管总噪声及排气背压 均满足技术要求． 

The tailpipe idle noise of a new car model severely exceeds the manufacture’s limits． The reason of inadequate lowfrequency anechoic performance and structural imperfection are obtained by analyzing the transmission loss of the muffler and the muffler’s interior flow field． The front muffler is optimized by using the crossflow perforation structure and the main muffler’s perforation form is improved． GT-Power simulation and test results show that lowfrequency anechoic performance of the muffler is improved，and the tailpipe idle noise decreases by more than 4dB( A) and 3dB( A) respectively at AC off and AC on cases． The total tailpipe sound pressure levels and the back pressure of the exhaust system at the 3WOT case satisfy the manufacture’s technical requirements．