Categories Of Mobile Machinery Fault Diagnosis

The technology of condition-detection and failure diagnosis of machinery equipment develops along with technologies of related fields such as modem testing technology, signal analysis and processing ,computer technology and theory of failure diagnosis .It receives great attention from companies /manufactures around the word ,and has been widely applied in industrial production. To adopt the technology of condition-detection and fault diagnosis ,company must above all estimate the present situation of equipments ,then decides the proper approach of maintenance according to it. As to the diagnosis method ,the theory and application of ATVFD ,Hibert Cepstrum are discussed in the thesis. The main subject of this paper is the fault diagnosis of diesel engines ,which drive the most port machineries .The vibration signal on cylinder surface of diesel engine is measured and combined with related characteristic parameters to realize the diagnosis of the trouble of the exhaust valve leakage and wear condition of piston and cylinder liner .Meanwhile ,the signal of cylinder pressure is restored indirectly by processing the vibration signal of cylinder head ,which has significant meaning in practical application. The signal of the crankshaft transient turning speed fluctuations is detected to reflect working condition of engine ,and by analyzing the speed waveform ,the operating conditions and related fault of the engine is obtained. The transient pressure signal of fuel oil-pipe is measured by using a clamp-on transducer on the injection line .Evaluation of the signal leads to estimation of the technical status of injection system and the diagnosis of the fuel system of the diesel engine.