The Study On Pass-by Accelerating Noise Control Of Vehicle

As the state limit pass-by accelerating noise data greatly, it is important project to control the automobiles noise for automotive enterprise. The cause of pass-by accelerating noise is so complex that the noise control is difficult. To control the noise effectively, the major noise must be identified first, and than taking various economical measures to reduce the major noise.This paper study the development and methods of vehicle pass-by noise control technology in and out of China. Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.By studying on pass-by accelerating noise control of vehicle, the pass-by noise of SC7080A and SC6360B is attenuated apparently. The pass-by noise of SC7080A is obviously decreased from 81.0dB(A) to 72.0dB(A) and the SC6360B is decreased from 75.5dB(A) to 73.7dB(A). The noise index has met with the second stage of latest rule of law. Through the research on this project, a suit of applied technology and method of pass-by accelerating noise control of vehicle is built up, which also can be extended to noise control engineering in different cars.