ABSTRACT
Sources of Engine Noise The following sources contributing to overall engine noise levels can be identified: 1. Radiation from engine casing and connected structures (crankcase,
sump, rocker covers, etc.) 2. Air intake (including noise from turbocharger) 3. Exhaust 4. Cooling fan and auxiliaries (injection pump, generator, etc.) It is not intended to discuss methods of noise reduction at source, since this is extensively covered in technical literature. The relative significance of each noise source and the engine design and operating characteristics which affect noise emission are discussed in general terms. Different types of engines may have very different noise characteristics. The noise level data given is intended as a guide only, for initial design purposes or in the absence of manufacturers’ data.
