Engine noise source identification is essential for making noise reduction strategies.Predominant noise sources of engines are normally identified as some cover components such as oil pan, valve cover and front gear cover etc. The radiated noise sources of a 6-cylinder construction diesel engine are identified with two methods-lead covering technique and surface vibration technique,and the ranking of the major cover on the basis of acoustic power is presented in this paper. Firstly the sound power level of these cover components and their contributions to the total acoustic power are determined with lead covering method under hemi-anechoic condition. Then the vibration characteristics of these components are investigated. The sound power level of various components is predicted via the mean square area average vibration. Both results basically agree well and verify the effectiveness of both techniques in engineering field.
