Application Of Noise Signal In Fault Diagnosis Of The Mini-diesel

Application of Noise Signal in Fault Diagnosis of the Mini-dieselIn recent years, the technique of mechanical fault diagnosis is quickly developed in domestic and overseas. As an important part of machine, it is significant to diagnose faults of the mini-diesel. At the same time, acoustical diagnosis technique has been paid more and more attention because of its maneuverability. In this paper, characteristic information of faults is accessed from diesel engine noise signal by using new method, wavelet-package, on the basis of former achievements and valid results.This paper attempts to research profoundly fault mechanism, fault feature extraction and fault diagnosis method of diesel engine from the view of practical application. Its research object is mini-diesel and its academic foundation is test technology, signal processing, wavelet analysis, pattern recognition and etc. the results show that it is effective and feasible to diagnose faults of mini-diesel engine by means of un-disassembly using surface acoustical signal. The paper consists following parts:1. The feasibility of the fault diagnosis by the noise signal of mini-diesel is demonstrated from the points of the choice of measure objects, measure position and relative parameters. And the relative equipments and parameters of the lab are chose. At the same time, I also studied the familiar fault of the KM178F mini-diesel such as the abnormal of the drain tap, the low pressure of the in gas, the obstruction of the oil-tube from the analysis of time series and frequency. The study indicates that the noise signal can be used to diagnose the fault of the mini-diesel without disassemble the diesel.2. The technology of wavelet-package is applied to abstract the character of the noise signals considering the special trait of the mini-diesel. And the method is applied to the KM178F mini-diesel. During the studying, the FFT is used to analyze the trait of frequency of the noise signal. The parameters of the wavelet-package analyze are chose base on the result of the FFT analysis. Considering the specialty of the KM178F diesel, the Db4 wavelet function is chose. The result of analysis testified that the identification of noise signal could be realized by using the characteristic vectors of the wavelet-package analysis result.In order to diagnose the fault of the mini-diesel automatically, the study uses the Euclidean to analyze and class the result of the wavelet-package. Finally, this method is applied in the fault diagnosis of the KM178F mini-diesel. The rate of the correction can reach 84.375%, and the effect is testified.3. Finally, the blue print of the fault diagnosis system of mini-diesel based on noise signal is put forward. The truss of the software is also advanced. The effect is also testified by putting it into the use on the fault diagnosis of the KM178F mini-diesel.The application testified that it can identify the working state of the mini-diesel by using the noise signal of the KM178F mini-diesel, thus, the automatic fault diagnosis of the KM178F mini-diesel is realized. As the...