Application Research Of Fault Diagnosis Technique In Locomotive Condition Monitoring Based On Instantaneous Speed

As Chinese railway transportation developing to higher speed and heavier load rapidly, monitoring the operation timely and accurately, predicting the potential malfunction or diagnosing the existing fault for the locomotive diesel become more and more important considering the safety and the economic benefits in the integrated management of the locomotive. Meanwhile, the condition monitoring and fault diagnosis is an important issue of diesel engine research, especially the online monitoring of the operating conditions and the real-time diagnosis of the working status of each cylinder,based on the instantaneous speed of the diesel engine, has become the leading research field of many scholars at home and abroad.In the technique of fault diagnosis based on instantaneous speed, it is essential to extract the diesel engine fault diagnosis principle by means of the inherent characteristics of the instantaneous speed. The basic method is trying to set up the diagnostic model of the instantaneous speed, carry on the corresponding waveform simulation and data analysis, and pick up the latent parameters, which reflected the uneven power capability of the cylinder, to achieve on-line monitoring, real-time diagnosis and accurate fault positioning of the diesel engines.The thesis is on the basics of the cylinder condition monitoring instrument, which is researched and developed by the Marine Automation Laboratory, Wuhan University of Technology. Combined with the practical application problems and the difficult research process, it has established the dynamic model of diesel engine crankshaft and conducted the application research of the fault diagnosis technique in the 16V240 locomotive condition monitoring based on the instantaneous speed. In this paper, it has completed the following tasks:1.Based on the analytic simplified model concerned on the diesel engine crank shaft, it discussed the nonlinear, coupling, damper, branch shaft, load fluctuations and other factors of torsion vibration, and analyzed the affect reasons of the abnormal fluctuations in instantaneous speed;2. According to the dynamic of the engine crank shaft, considering the physical structure of 16V240ZJB diesel engine, it has built the shaft equivalent models. What's more, it has simulated the instantaneous speed of diesel engine and compared the waveform with the simplified model;3. Relying on the equivalent model established, it has compared the model simulation waveforms with the measured waveforms collected from the scene, contrasted the similarities and differences between the normal and the fault waveform, deduced the fault diagnosis theory based on the instantaneous speed and analyzed the practical application of the fault diagnosis technique;4. In view of the current diagnostic problems reflected, integrated with the market feedback information, it has improved the hardware and software of the 16V240 locomotive diagnostic system, completed the Linux application porting platform and set up the condition monitoring system of locomotive diesel engine.