中文摘要：

针对柴油机噪声源的特点，以柴油机的表面辐射噪声信号为依据，应用层次分析法对发动机的噪声源进行了识别。建立具有目标层、频率层和噪声源层3个层次的结构模型，在各个频率段，比较柴油机不同部件的表面噪声信号，构造层次判断矩阵，计算各噪声源对噪声评价点影响的权值，考虑噪声辐射表面积后进行总排序，识别出柴油机的主要噪声源为齿轮室罩，是降噪的重点。

英文摘要：

In view of the characteristics of diesel engine noise source, and based on the radiated noise signals on diesel engine surface, the noise sources of engine are identified by applying analytic hierarchy process technique. A hierarchy model with three layers （objective layer, frequency layer and noise source layer） is built. The surface noise signals on different components of engine at different frequency segment are compared, and a hierarchy judgment matrix is constructed. The weighting factors for the effects of noise source on noise evaluation points are calculated, and after taking into account the area of noise radiating surface, the overall order in terms of noise contribution rate is sorted. Finally the major noise source of diesel engine identified is gear set cover, being the focus of noise reduction.