Effects of a Rapid Pressure Rise on Engine Vibration and Noise 900013
This paper describes the origins of I.C. engine noise induced by the rapid pressure rise due to combustion.
Comparative assessments are made of the magnitude and characteristics of the rapid pressure rise resulting from spontaneous combustion i.e. “knock”, and its effect on noise, in both diesel and spark ignition combustion systems. The response of both the combustion chamber cavity and the engine structure is defined and discussed.
The characteristics of the cylinder pressure developments of various diesel combustion systems, namely direct-injection, indirect-injection, and turbocharged, are classified in terms of the rates of pressure rise, the peak pressures, and the cylinder pressure spectra.
Reasons for the higher noise levels emitted by car diesel engines when compared to equivalent spark ignition engines, are postulated.