Identification of Mechanical Sources of Noise in a Diesel Engine: Sound Emitted from the Valve Mechanism

Abstract

The sound emitted from the valve mechanism of a diesel engine was investigated by standard methods of sound and vibration analysis augmented by correlation of incidence of individual transient components. This latter technique makes use of information obtained from the tuned output of the noise signal focusing attention on the incidence of single-frequency transients. Three distinct sources of noise were exposed: valve-gear transmission mechanism, valve impact, and the flow of air through the valve gaps. The characteristics, relative contributions, and effects of these sources are discussed in detail, and insight is gained into the mechanism of noise generation and radiation.