基于相干功率谱分析的复杂柴油机噪声源识别

噪声源识别是降噪的前提和基础，基于相干功率谱分析方法，并结合层次识别理论能够对柴油机复杂噪声源进行识别。识别中对振动和噪声信号进行相干功率谱分析，并构建柴油机噪声的复杂噪声层次诊断结构图和层次判断矩阵，进而通过层次排序识别出柴油机的主要噪声辐射源。结果发现：低频段噪声主要是供油泵、齿轮、配气机构等运动部件的机械噪声，齿轮室罩、气门室罩等薄壁件是噪声的主要辐射部件；而高频段主要为燃烧噪声，油底壳则是降噪的重点。

Identification of Complex Noise Source of Diesel Engine Based on Coherent Power Spectrum Analysis

Noise sources identification is essential for the reduction of engine noises. In this paper, identification of complex noise source of diesel engine based on coherent power spectrum analysis and hierarchy diagnosis is presented. For investigating the noise source, the hierarchy diagnosis chart and hierarchy judgment matrix are provided. By taking noise source identification, the main source of radiated noise was identified. The result showed that the noise with low frequency belt was mainly from mechanical noise in oil pump, gear and valve mechanism etc. , and thin-walled part like gear cover and valve cover etc. are major radiated sources; while the noise with high frequency belt was mainly from combustion noise. Reduction noise in oil pan is key to the reduction of engine noise.