Abstract
The paper presents a method for processing acoustic signals which allows the extraction, from a very noisy signal, of components which contain diagnostically useful information on the increased valve clearance of a combustion engine. This method used two-stage denoising of the acoustic signal performed by means of a discrete wavelet transform. Afterwards, based on the signal cleaned-up in this manner, its entropy was calculated as a quantitative measure of qualitative changes caused by the excessive clearance. The testing and processing of the actual acoustic signal of a combustion engine enabled clear extraction of components which contain information on the valve clearance being diagnosed.
Highlights
Combustion engines are very important components of means of transport and their reliable operation during service is vital
The paper presents a new method for processing vibroacoustic signals which enables diagnosing excessive combustion engine valve clearance by using two-stage signal denoising and entropy calculation
The developed method made it possible to remove irrelevant components of the acoustic signal of the engine and to leave only these components which are responsible for carrying information on the diagnosed clearance
Summary
Combustion engines are very important components of means of transport and their reliable operation during service is vital. An interesting application of vibration signal processing methods was presented in [19], where the use of the continuous wavelet decomposition made it possible to separate signals caused by the combustion process and those caused by the excessive clearance of the piston in the cylinder sleeve. As part of the research presented in the paper the authors propose the use of a new complex acoustic signal processing method developed in order to diagnose excessive valve clearance. This method used denoising [45,46,47] of the acoustic signal realized in two-stage performed by means of a discrete wavelet transform [48,49,50,51]. The testing and processing of the actual acoustic signal of a combustion engine enabled the clear exposition of its significant components which contain information on the diagnosed valve clearance
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