Research On Fault Diagnosis Of Engine Piston Striking Based On Wavelet Packet Transform

The mechanical fault diagnosis is more and more inclined to analyze and process the fault by analyzing the vibration signal of mechanical equipment.The engine body surface vibration is an important source of piston knock,so the engine piston stroke monitoring can ensure the normal operation of the engine,while improving the safety and reliability of the engine.Two order motion and the piston piston knocking fault of the class,so the vibration characteristics of the two order motion and the piston knocking fault monitoring,it can be very good for the piston to make an accurate judgment of fault and state.In this paper,the piston knocking fault of the engine is taken as the research center,and the characteristics of the piston striking and the piston striking are studied deeply.The processing method of the vibration signal,the processing method of wavelet packet transform,simulation process and vibration signal processing method by some signal,compared with other methods,shows the advantages of wavelet packet transform.In the study of the piston knocking fault analysis and processing,establish such as piston and cylinder model dynamics,the obtained parameters of processing,two order motion simulation software AVL EXCITE Piston&Ring competed with the gamma of piston is analyzed into,and the fault set,get the vibration signal of the frequency of piston knocking.The degree of fault feature is estimated by the processing of wavelet vibration waveform.Finally,through the data and results of the wear trend of piston cylinder liner of fault prediction,wear characteristics from that of piston percussion vibration further analysis and discussion,finally summarizes the relationship between the wear characteristics of piston in the piston cylinder liner.Piston liner wear general,is knocking at the factory will have a larger energy,but with the expansion of the gap appears on the wear energy decreases,and finally with the enlarging gap of piston cylinder liner of the percussive energy will gradually become larger,which will obviously knock fault show.Based on the above research,it provides a theoretical basis for the follow-up diagnosis of piston knocking fault.