CG125型摩托车主要噪声源识别及排气噪声控制研究

【作者】 姜勇；

【导师】 张建武； 史重九；

【作者基本信息】 上海交通大学 ， 车辆工程， 2008， 硕士

【摘要】 噪声水平是评价机动车辆等级水平的重要指标之一。摩托车噪声作为机动车的一种,噪声对其品质影响较大,且具有环境危害性。目前国内外不断加严摩托车噪声标准,发达国家正在斥巨资研究摩托车加速行驶噪声的控制。我国虽然从上世纪80年代起也逐渐重视这一工作,在标准制定和法规管理上逐步与国际接轨,但我国摩托车行业整体水平仍相对落后,对摩托车噪声的控制研究尚处于初级阶段。本文阐述了摩托车的噪声产生的机理和摩托车主要噪声源的识别方法。在此基础上,采用Beamforming声场全息成像技术和SONAH统计学优化近场声全息技术对一典型的125摩托车的主要噪声源进行定位,并分析排气噪声的频谱特性,确定发动机的排气噪声是该车型主要噪声源。在噪声试验的基础上,本文根据排气噪声产生的机理以及消声器的消声原理,确定改进优化设计方案。建立排气消声器的CAD模型和声学数值模型,运用声学仿真软件SYSNOISE确定排气消声器的传递损失,并提出使用回转迷宫式消声腔和使用穿孔管等消声单元来消除噪声通过频率的改进思路。通过对摩托车加速行驶噪声试验以及整车动力性能试验,验证了新设计的排气消声器满足了该摩托车消声性能的要求,使整车加速噪声达到了最新国家标准的要求。同时,新设计的排气消声器也符合整车动力性能的要求,这证实了对排气消声器所采用的优化改进方法的合理性。更多还原

【Abstract】 The noise level is an important index in the process of evaluating the quality of motor vehicles. As a kind of the motor vehicles, the noise of motorcycle plays an important role in the noise pollution. With more stringent statutory establishments to the pass-by noise in home and abroad, the noise control of motorcycle has became more urgent, but, in China, it’s still at a primary stage.In this paper, the generating principle of noise and the identification of noise source of motorcycle are introduced, respectively. Based on these principles, the test of the noise source identification of a typical 125cc motorcycle is carried out using Beamforming and SONAH technologies, simultaneously, the frequency spectrum of the exhaust noise is analyzed. According to the above test results, the exhaust noise of the engine is considered as the main noise source of the motorcycle. Based on the test and the muffling principle, the optimizing program to the exhaust noise is determined. Firstly, the CAD modeling and the acoustic numerical modeling of the muffler of the motorcycle are established; secondly, the transmission loss of the muffler is calculated by SYSNOISE. In terms of the test and simulation results, the muffler acoustic units of the labyrinthic chamber and perforated pipe are employed to improve the muffling performance of the muffler.The new exhaust muffler shows good acoustic performance in the pass-by noise test, and does not reduce the engine power, which validate the rationality of the optimization methods to the muffler and make the exhaust noise of the motorcycle satisfy the latest national standards,更多还原