Frequency Spectra of Diesel Engine Heat Release Rate, Pressure Development and Engine Noise: An Experimental Investigation of Cause and Effect Relationship

Experiments were performed to examine the cause and effect relationship between the Diesel Engine Heat Release Rate, Cylinder Pressure Development and Engine Noise. The periodic heat release rate, pressure development and the noise from the engine exhibited a very high degree of causal relationship at frequencies below 2 kHz and somewhat lower but still significant causality at higher frequencies. The results seem to show that the noise produced by the Diesel engine is essentially dominated by low frequency components of the pressure trace and therefore manipulation of the pressure trace will have only a limited effect on the noise of Diesel engines.