Diesel engine noise under acceleration

The diesel engine is now the most common powerplant for medium and heavy goods vehicles. In general diesel engines emit more noise than gasoline engines mainly because of their combustion processes and it is the diesel engined vehicle which produces the peak sound levels on our roads. Most of the published works on engine noise deal with engines which operate at steady full load conditions. Yet the noise regulations iso r362, ADR 28a and SAE j366b prescribe driveby test under acceleration, and frequently it is the sound of an accelerating truck which causes the greatest community disturbance. The aim of this paper is to promote a better understanding of the underlying engine parameters which control the noise during acceleration. To this purpose the combustion and fuel injection systems of three diesel engines are discussed together with their noise levels during acceleration.