Study on the Detection of Misfiring Cylinder in a Multi-Cylinder Diesel Engine Loaded on the Practical Machinery

摘要

As a motive power in heavy construction machineries including mining and various construction works, a multi-cylinders type of diesel engine is very often used because of its high cost performance. Steady maintaining of diesel engine's operation is substantial in view of economic demands and environmental concerns. To realize this, a practice of early diagnosis and early repair are essential. In our previous study using a V-12 type of diesel engine installed on a bench, we demonstrated that a misfiring cylinder could be detected by statistical analysis method using rms value of the acceleration waveforms measured on a single point of the engine block. In this paper, the same experimentation and analyses as in the previous study were conducted for two practical machineries that loaded the same type engine of the previous study. Even though the engine was loaded on a practical machinery, it was found that a misfiring cylinder could be detected by the same way as in the previous study. In addition to the analyzing method in the previous study, in this study, we employed a wavelet transform method with the Gabor function as a window, and analyzed the acceleration waveforms. The results of wavelet analysis revealed that a misfiring cylinder could be detected visually from time-frequency charts. With the aid of statistical analysis using rms value, a misfiring cylinder in a multi-cylinder diesel engine can be doubly checked by wavelet analysis.