Reducing Noise from Heavy Diesel Trucks by Engine Compartment Shielding

A large number of laboratory tests on diesel engines have proved that noise emission can be reduced by more than 10 dB by applying insulation directly to the engine or by totally enclosing the engine. However, the application of these methods on trucks involves appreciable difficulty and time-consuming design modifications.

This paper describes how significant noise reduction can be attained merely by soundly designed shielding, without the need for modifying the basic design of the truck. The method is based upon experience from other types of vehicles which, for a number of years, have already been equipped as standard with similar insulation.

The reduction attained in the noise emission is approximately 6 dB(A). Inconvenience during repairs and service has been reduced to a minimum by a well-planned design and simple mounting of the shields as well as ample exposure of the engine when the cab is tilted.