Design of Muffler in Reducing Hiss Noise of Turbocharged Vehicles

The application of turbochargers in fuel vehicles brings high-frequency noise, which seriously affects the vehicle's ride comfort. The hiss noise of a turbocharged car is improved in this paper. Firstly, under different operating conditions and whether the air intake system is wrapped, the noise in the vehicle cabin and the driver's right ear is tested, and the noise sources and noise characteristics are identified. Then, the acoustic calculation model of the muffler is established, and the transmission loss (TL) of the original muffler behind the turbocharger (MBT) is calculated. The TL of the muffler is measured by the double-load impedance tube method. The finite element calculation model is verified by comparing the TL of muffler calculated with tested. Thirdly, the MBT is redesigned. The improved muffler significantly improves the performance of eliminating high-frequency noise, and its TL beyond 20 dB is expanded to the band of 1600 ~ 3500 Hz. The improved muffler is trial-manufactured and installed on the test vehicle, and the vehicle noise is tested again. The test results show that the noise in the frequency band of 1600 ~ 2400 Hz is obviously reduced in the near field of the MBT, and the maximum reduction is 9 dB. The subjective evaluation also shows that the high-frequency hiss noise also improved significantly in the car. This paper proposes a method of designing a muffler and optimizing its structure to reduce hiss noise of turbocharged vehicles. The influence of airflow on engine performance is considered. It can provide a reference for the application of engineering development of turbochargers.