Application of a Continuous Wavelet Transform for the Diagnosing of Excessive Valve Clearance of the Combustion Engine

Abstract

Combustion engines are the components of means of transport which during service are exposed to the occurrence of excessive clearances. The diagnosing of the condition of the engine requires developing methods which could be useful during both continuous and single checks of the engine. Application of measurements and acoustic signal processing may facilitate a quick diagnosis of the engine without any additional disassembly work. As part of the study, research was conducted to develop a non-invasive method of diagnosing excessive clearance of the combustion engine. Based on the recorded acoustic signals of the combustion engine and reference signals of the momentary crankshaft position, a method was developed to diagnose an increased valve clearance in the combustion engine. In this method, processing of the recorded acoustic signals by means of the continuous wavelet transform was applied together with a comparison of their instantaneous energy, depending on the crankshaft rotation angle and timing angles, as well as the scale parameters of time and frequency distributions.

Failure Progress of 3D Reinforced GFRP Laminate during Static Bending, Evaluated by Means of Acoustic Emission and Vibrations Analysis

“…On the basis of the further tests performed by the authors, [ 66 ] presents a new method of vibration signal separation in classic laminate samples. It considers signal processing with the use of a continuous wavelet transform [ 67 ], signal separation in the domain of the frequency scale [ 68 ] and, next, calculation of the averaged signals and kurtosis, as an energy spot measure of the information included in the vibration signal. The schematic algorithm used in this method is presented in Figure 14 .…”

The Use of Denoising and Analysis of the Acoustic Signal Entropy in Diagnosing Engine Valve Clearance

“…This type of research was also conducted by the authors of [10], which analysed various types of damage to fuel injectors as well as damage to one or two injectors. In [11,12] damage to the hydraulic tensioner of the timing chain system was studied and in [13][14][15][16][17][18] the excessive valve clearance of the combustion engine. Vibroacoustic signals were also used in [19,20], where excessive clearance between the piston and the cylinder sleeve of the engine was detected.…”

“…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. The authors of [13][14][15][16][17][18] presented the possibility of using signal filtration in order to separate components related to the increased valve clearance from components resulting from the combustion process. On the other hand, in [15,16] discrete and continuous wavelet transforms were used for diagnosing the valve clearance based on recorded acoustic signals.…”

“…The authors of [13][14][15][16][17][18] presented the possibility of using signal filtration in order to separate components related to the increased valve clearance from components resulting from the combustion process. On the other hand, in [15,16] discrete and continuous wavelet transforms were used for diagnosing the valve clearance based on recorded acoustic signals. These methods enabled the separation of components which contain noise and to leave for further analyses low-energy components which contain information on the change in the value of the valve clearance.…”

Analysis of vibroacoustic estimators for a heavy-duty diesel engine used in sea transport in the aspect of diagnostics of its environmental impact

“…The originality pertains to the research method, its application in marine transport, research conditions and the approach to the diagnostic evaluation. The incorporation of the actual operating conditions of the object [3][4][5][6][7][8][9] and new variables of the fuel injection process (injector design, fuel feed conditions, reception of the measurement signal from the injector and the cylinder wall and injector wear) only add to the originality of the authors' approach to the study on the research problem supplemented by the application of vibroacoustic signal in this type of analyses.…”