Application Research On Fault Cylinder Diagnosis Of Motor Engine Based On Motor Car

With the developments of country economy and transportation, the motor is used extensively, and becomes one of the symbols of modern society. But the configuration of internal combustion engine is complicated , and it works at the serverely condition, and ICE has high failure rate and high price of maitaineance. So, it is necessary to find a simple and effective method of ICE fault diagnosis. Since the angular vibration signals of crankshaft contains a lot of information about power condition of ICE, based on the latest diagnosis theory of angular vibration, it carried out the diagnosis on fault cylinder with car sensor, which is simple and accurate and has more applied value.Through the measurements and analysis on the angular vibration of experimental engine, it showed that the minimum natural frequency of angular vibration is about 100Hz, and it meets the demands of the angular acceleration fluctuate method on the shafting rigidity at lower speeds, and also meets the 0.5 order phase diagnosemethod on the vibration mode of shafting angular vibration through out the working speed.The instantaneous speed measured by car sensor and the measuring system of angular vibration, can be differentiated to get angular acceleration, and the phase angle of 0.5 order angular vibration can be received from integrating and fourier transformation instaneous speed.After analyzing the ralation between the transient speed singal and anglar acceleration and fault cylinder, it showed that it is difficult to pick up diagnosis parameter of fault cylinder from instantaneous speed, and the angular acceleration has obvious curves corresponding to each cylinder. Therefore it presents two non dimention parametters-angular acceleration changeable index and area index, and diagnoses the fault cylinder, also compares the diagnosis effect of the two characteristic parameters which concluded that the area index has better diagnosis.On the basis of the property of angular vibration of F23B engine crankshaft.