Research On Noise Of Engine Distribution Mechanism For CG125 Motorcycle

With the development of industry, transportation and society, the higher demand for decreasing the noise of engine which acts as original main power source is bring forward. Noise index has become an important aspect in evaluating engine's performance, and the research for analysis and controlling engine noise is significance. Fundamental theories about vibration and noise especially precedential research on engine noise are summarized. On the basis of analyzing engine's structure and working principle, the origination mechanism, transfer path, influential factors and control measures of engine noise are analyzed in details. Some methods of noise source identification are also discussed. Proceeding from the distribution mechanism of CG125 engine series, its motion law is researched, especially the changing law of valve clearance with the engine temperature is researched deeply; Finally the improvement measures for reducing valve clearance change are put forward, and is validated to be good effective by the experiments in decreasing the noise of distribution mechanism of CG125 motorcycle engine series.