Concept for a Chassis Mounted Capsule of Engine and Gearbox for Heavy Trucks

The proposed reduction of noise by international legislation will probably result in a limit of 80 dB(A), measured according to ISO R 362. In order to obtain a uniform noise level for all categories of vehicles, the 80 dB(A)-limit is also forecast for heavy trucks in about 5 to 10 years. With a high powered conventional Diesel-engine, this limit can only be reached by complete enclosure of engine and gearbox. In this paper, we present a capsule mounted on the chassis, adapted to the cramped space conditions in a European truck. The design has the advantage of ease of maintenance, since it is possible to attatch the upper capsule parts to the tipping-cab. The results of the noise and temperature measurements are also reported. The great reduction of the surface noise by the capsule requires the installation of a radiator-fan-system, which is designed to reduce noise considerably.