Fault Diagnostic Studies Of Marine Multi-cylinder Diesel Based On Instantaneous Speed Signal

It is of great significance to research on the Fault diagosis in diesel engine by using instantaneous speed signal, which has a good economic performance and adaptability for long-term online monitoring and fault diagnosis. Currently, the method is widly uesd in the diesel which has seldom cylinders and long Ignition interval angle.As for multi-cylinder, it’s too many cylinders that power storkd superimpose on each other, which has a great coupling effect. It’s too hard to diagnose the fault degree and the location of the fault cylinder by using normal waveform feature parameters in the diesel engine which has a large imbalance among cylinders. According to the working principle of diesel engine, this paper calculate the simulation signal and measure the instantaneous speed signal through the experiment, research on the application of fault diagnosis in multi-cylinder by using crankshaft speed fluctuations.(1) First, analysis the principle of the crank mechanism, establish a simplified model and a rigid model. Compute the simulation signals by two models, and compare with the real instantaneous speed to find the better one as the final simulation model.(2) Then, sum up the regular among the degree of fault, the location of fault cylinder and the speed signal. Find out the parameters that contain the fault infromation, and bulid up the fault diagnosis standard by using the parameters. Discuss the influence of the volatility of factors on parameters.(3) Next, mesure the instantaneous speed signal, and anlysis the original signal. Extract a few common characteristic parameters, comapre the regular of different parameters and fin out the best one as the fault diagnosis parameter.(4) Finaly, statistic the sample data and get the thersholds of various states, establish the fault dianosis model. Test and verify the accuracy of the model by using the data in test sample library.