RESEARCH PROJECT FOR REDUCING THE NOISE OF TRUCK DIESEL ENGINES

The first efforts to attenuate noise from motor vehicles go back to the 1930s. Significant developments in noise attenuation research culminating in 1974 with the presentation (FVV-AVL) of a water-cooled and an air-cooled research engine enclosed in a close-fitting capsule are addressed.

Two basic studies are described as representative of individual research carried out by commercial vehicle manufacturers: body-mounted capsules for diesel truck engines and tests on close-fitting capsules performed on the test stand.

The enclosed water-cooled engine and a basic engine without a capsule were each mounted on a truck chassis in order to test the effectiveness of the capsule and to compare measurements taken with the enclosed engine on the test stand with those taken with the engine in the vehicle. Despite the discrepancies between the two sets of data, the results of the vehicle tests were satisfactory.