Garg N., Bhattaccharya M., Jain S.

The paper describes an investigation of noise sources identification of a diesel engine carried out to obtain sound intensity and sound power level for five engine surfaces viz. front, right, left, back and top in the frequency range from 200Hz to 4000Hz. The work focuses on the investigation for the effect of two important operating parameters viz. engine speed and engine load on the over all levels of engine noise using sound intensity technique. With the sound intensity method, the major sources of the exterior radiation noise of the engine are surveyed. Intensity mapping and Sound Power spectrum have been developed for five engine surfaces using Noise Source Identification software. Sound Power radiation of important noise radiating components viz. flywheel, pulley and engine block etc. have been presented for different combinations of operating parameters. Finally significant noise radiating components have been identified and some methods to decrease the structure noise radiation have been discussed. The research provides a reliable basis for the engineering practice to reduce the vehicle noise level. Keywords: Diesel engine, sound intensity, sound power level, Noise sources identification.