This paper studies the characteristics of Diesel engine air-borne acoustic signals using time-frequency domain techniques. One analysis technique is investigated: Continuous Wavelet Transform (CWT) which is reviewed from the mathematical point of view, based on its developmental stages, drawbacks and the subsequent improvements.
The detection capabilities of this technique are evaluated using air-borne acoustic signals collected from diesel engine in acoustically untreated laboratory.
Some engine conditions and faults are investigated using CWT techniques. The achieved results prove the technique’s sensitivity to engine’s speed and load variations. More important, the CWT shows excellent capabilities in detecting engine’s injection process and lubrication related faults at early stages. At the end of the paper, summary is given.