【作者】 张志强；

【导师】 高文志； 吴坚；

【作者基本信息】 天津大学 ， 动力工程（内燃机）（专业学位）， 2014， 硕士

【摘要】 随着社会的发展和科技的进步,人们对汽车的舒适度提出了更高的要求,其中最重要的一方面就是汽车的振动噪声问题。发动机是汽车的动力核心,同时也是最主要的振动噪声源,因此,发动机的振动噪声控制受到了国内外学者的广泛关注。研究发现,当噪声强度降低到一定程度时,声压级的高低已不能继续反映人们对于噪声信号的主观感受,因此对于声品质的研究具有很强的现实意义。本文首先采用基于声信号的内燃机测试分析技术对汽油机的噪声源识别展开研究,以某车用2.0D汽油机作为研究对象,采用独立成分分析的方法对九点噪声信号进行盲源分离,分析各独立成分的幅值和频率随时间的变化特性,并结合汽油机的结构和噪声辐射机理,成功识别出汽油机各主要噪声源。与此同时,利用声阵列法在特定频率下对汽油机进行可视化声源定位测试,以验证独立成分分析的计算结果。为了研究各噪声源对声品质的影响,对典型工况下的噪声样本进行带阻滤波处理,得到8个不同的噪声样本,并计算其心理声学参数和感觉满意度系数,得到各主要噪声源信号对声品质的影响。为了研究噪声信号的频率分布和阶次对声品质的影响,本文选用声品质表现较好的丰田Corolla汽油机进行噪声对标实验,分析两台汽油机各稳态工况的频率分布差异,并对2.0D汽油机进行315Hz—1250Hz频率段和3150Hz—6300Hz频率段的带阻滤波处理,计算滤波后声音样本的心理声学参数和感觉满意度系数,得出频率成分对声品质的影响;对比两台汽油机加速工况阶次噪声的能量大小和分布情况,得出阶次噪声对声品质的影响。最后,利用GT-Power软件对2.0D汽油机的进气口噪声进行仿真优化,并建立发动机进、排气系统和表面辐射噪声声品质仿真优化流程,同时创新性的提出在原始设计阶段提升声品质的想法,并给出声品质正向开发流程。更多还原

【Abstract】 Along with the development of society and the progress of science and technology, people have higher demands for the comfort of vehicle, one of the most important aspect is the problem of noise, vibration and harshness. Engine is the key power of vehicle, and it’s also the main source of noise and vibration, therefore, the issue of noise and vibration control has become the focus of research area. At the same time, the study found that when the noise intensity decreased to a certain degree, the subjective feeling for the sound cannot be reflected by the sound pressure level, so it has an important practical meaning for studying the sound quality.In this paper, noise source identification of gasoline engine was studied based on acoustic signal test and analysis. An automotive gasoline engine 2.0DCVVT was taken as a study object, independent component analysis(ICA) was used to blind source separation(BSS) of noise signal and the independent components(ICs) were obtained. Then analyzed each IC time-frequency characteristics, and combined with the structure of gasoline engine and noise generated principle to identify each IC correspond to noise source. Meanwhile, the acoustic array technology was used to take the experiment of noise source identification at a particular frequency, so that it can verify the results of independent component analysis.In order to study the effects of noise source on the sound quality, the typical noise sample was chosen to do the band-stop filter processing, and 8 different samples were obtained. After calculated and compared the coefficient of psychoacoustics parameters and sensory pleasantness, the result can be obtained.In order to investigate effects of the frequency and order distribution on sound quality, the Toyota Corolla gasoline engine was selected to take the contrast noise experiments, the difference of frequency of the two engines can be analyzed. The frequency ranging from 345 Hz to 1250 Hz and 3450 Hz to 6300 Hz were filtered from 2.0D noise samples. After calculated and compared the coefficient of psychoacoustics parameters and sensory pleasantness, the influence of frequency components on sound quality can be obtained. After compared the order distribution of two engines speed up conditions, the influence of order distribution on sound quality can be obtained.Finally, the GT-Power software was used to optimize the intake noise sound quality of 2.0D gasoline engine, after that, the engine intake and exhaust system and the surface radiation noise sound quality simulation and optimization process were established. There is also an innovative idea that to improve the sound quality during the original design stage, and the sound quality development process was established.更多还原