【作者】 李伟；

【导师】 邓兆祥； 汪正胜；

【作者基本信息】 重庆大学 ， 车辆工程， 2006， 硕士

【摘要】 由于国家对汽车加速行驶车外噪声限值日益严格,目前汽车生产企业把降噪看作是主要的科技攻关项目之一。汽车所产生的车外加速噪声成因复杂,分析困难,要有效地控制汽车车外加速噪声,首先要能准确地确定各声源所产生的部位从而寻求主声源,再结合各主声源噪声产生机理和传播途径,制定经济有效、切实可行的降噪措施。本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施,在此基础上,结合SC7080A和SC6350B汽车的车外加速噪声水平及现状,综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法,对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案,针对SC7080A,主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器,抑制空气滤清器壳体表面和进气口两处的噪声辐射,根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器,并进行了工程化设计和试制;针对SC6360B,主要改善了排气消声器在高频段的消声性能,对罩壳类零件进行了结构改进,降低了其表面噪声的辐射,并对发动机舱进行了吸声、隔声处理,设计了发动机隔声罩。通过对SC7080A和SC6360B汽车车外加速噪声的控制研究,取得了较为满意的噪声控制效果,使加速噪声评价值显著下降,SC7080A由改进前的81.0dB(A)下降至72.0dB(A)左右,SC6360B由改进前的75.5dB(A)降到73.7dB(A),达到了最新限制法规的第二阶段74dB(A)的限值要求。通过本项目的研究,最终形成了一套实用的汽车车外噪声分析研究和控制的方法与技术,适合推广应用到其它相关车型的噪声控制工程实践中去。更多还原

【Abstract】 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.更多还原