摩托车进气噪声控制研究

【作者】 张蕾；

【导师】 汪鸿振； 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性能指标之一,摩托车噪声作为机动车噪声的一种,在其中占有相当的贡献量,具有很大的危害性。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。我国从上世纪80年代起也逐渐重视这一工作,但对摩托车发动机进气噪声的控制尚处于初级阶段。本文简单地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125mL级摩托车的主要噪声源进行定位,并分析进气噪声的频谱特性,指出发动机的进气噪声是该车型主要噪声源之一。发动机进气噪声大多属于低频噪声,研究结果表明提高空气滤清器1000Hz以下的消声特性是控制进气噪声的重要途径。本文根据进气噪声产生的机理以及扩张式消声器的消声原理,确定设计方案,建立空气滤清器的CAD模型和声学边界元模型,通过声学仿真的方法计算出空气滤清器的传递损失,设计了单扩张腔式空气滤清器。根据分析、研究结果,加工了新型空气滤清器模型,通过摩托车加速行驶噪声试验以及空气滤清器进气阻力试验,验证了新设计的空气滤清器满足了该摩托车消声性能的要求,使整车加速行驶噪声下降了1.1dB,同时新设计的空气滤清器也符合发动机空气动力性的要求。而且具有结构简单、消除低频噪声的性能良好和流动损失小的优点,说明对空气滤清器所采用的设计方法和原理是正确的。更多还原

【Abstract】 The noise is an important performance to evaluate the quality of motor vehicles. As one kind of the motor vehicles, the noise of motorcycle plays an important role in the noise pollution. Because of the more stringent statutory pass-by noise requirements at home and abroad, the developed country furnished funds for researching the noise control of motorcycle. Our country paid great attention to the research gradually after 1980’.This paper expounds the special generating mechanism of the motorcycle noise and the technique of distinguishing the motorcycle noise sources simply. Basing on these theories, we measured one representative motorcycle engine and induction noise spectrum by means of the Beamforming and SONAH measurement. The induction noise was one of the main noise sources, and it did an important contribution to the pass-by noise. Engine induction noise is mostly in the low frequency region. The conclusion can be got that the improvement of acoustic performance of air-in filter below 1000Hz is very important to reduce the induction noise. This paper designed the air-in filter with only one expand chamber according to enter creation mechanism of annoy the voice and extend type filter of a machine a principle into the spirit. The CAD model and the boundary element model were founded. The transmission loss was calculated based on the boundary element method.According the result of numerical simulation the CAD model was founded, then the physical model. The new air-in filter showed good acoustic performance in the pass-by noise tests, the pass-by noise descends 1.1dB, and do not to the power and the induction efficiency of the engine. Finally, it has inherent characteristics in reducing low frequency, small pressure loss and simple geometry, the methods and principles used in the course of filter design are correct and workable.更多还原