The Use of Specially Designed Covers and Shields to Reduce Diesel Engine Noise 730244
Possibilities of design and construction are presented by which the noise radiated by the surface of an engine can be reduced.
Vibration isolation, stiffening, or sound-reducing shells, can be applied within comparatively short time; however, their effect on reducing the total noise is restricted to about 5 dBA.
Total enclosure of the engine is highly effective. In this particular design, the space requirement is comparatively small, the weight increase is not too excessive, sound-absorbing material in the clearance is not required, and the noise reduction achieved is as high as 15-20 dBA.
New design concepts, taking into account acoustical principles right from the start, will be the most economical approach for the future. Knowledge of the structure-borne sound within the engine is essential in this respect; particularly, further knowledge gained through tests on the nonrunning engine, using a “banger rig” for simulating combustion excitation.