Research On The Sound Insulation Theory And Experiment Based On Noise Of Motorcycle

Noise is one of the most important criterions to evaluate the quality of vehicles. With public attention increasing and limitation becoming more and more rigid, motorcycle noise control has become an important and urgent task in motorcycle industrial development. Aimed at the current situation of the research on motorcycle vibration and noise, and taking an example of 125-C motorcycle, this paper mainly discussed on main-noise-source diagnosis, noise characteristic analysis. Based on the sound insulation theory and experimental technology, a modification design on the fairing cover of motorcycle engine intake was executed for the purpose of reducing noise of motorcycle.The paper first analyzed the category of motorcycle engine noise, generation mechanism, and summarized noise controlling method, the main-noise-source diagnosing identification method. All of these works made a wonderful preparationfor the noise control of motorcycle.Secondly, by the means of noise-source diagnosis identification methods, including near field sound pressure measurement, sound intensity measurement, and order track analysis, and taking 125-C motorcycle as an example, a detailed research on noise source distribution and main noise sources identification was presented. Based on the conclusion of diagnosis that the induction noise was one of the most important noise sources of motorcycle, this paper put forward an efficient solution to reduce the induction noise - applying sound insulation technology to the fairing cover of motorcycle engine intake.Thirdly, a detailed analysis and comparison among sorts of acoustic materials including sound insulation material, sound absorption material, damping material and composite material, had been conducted. Based on comparison, developed a sound insulation model which was used as the basis of experimental research.Final, by a series of compare experiments on the material and structure of the fairing cover, the conclusion showed the fairing cover of motorcycle engine intake should be improved basing on sound insulation theory. Moreover, in considering economy, feasibility and function requests, this paper put forward a practical scheme.By experimental analysis, the final fairing cover model achieved a wonderful acoustic effect of reducing noise by 1.2dB. Combining air-in filters design, they may reduce the induction noise effectively considering the request of sound insulation theory and engine intake ventilation.