Research On Fault Diagnosis Of The Gas Engine Cylinder And Its Application

As one kind of diesel engine, the gas engine plays an important role in the professions of petroleum, chemical industry, shipping, vehicle and aerospace. It provides power for them and its operating period and status are closely related to the reliability of the system and the efficiency of enterprises. If there is a safety incident of gas engine, it will bring significant impacts on many aspects. With the development of the centrifugal engine, people started to pay more attention on reciprocating engines. Because of this, further development of engine fault diagnosis is particularly necessary. At the present, the main methods for diagnosis of engine include vibration monitoring, liquid analysis, state parameters monitoring, instantaneous angular speed monitoring and intelligent methods. The vibration monitoring and instantaneous angular speed monitoring are widely applied.The vibration signals are one of the common signals in diagnose faults because the signals contain a wealth of information. In this paper, we monitor the vibration signals of a four-stroke-eight-cylinder engine and add the signals together in angular domain. Then we make the igniting order and the crank angle correspond. So we can know the fault cylinder number from the crank angle directly and early warning of misfire fault is achieved. On the other hand, owing to the number of sensors cutting down, the input costs are reduced obviously.The instantaneous angular speed signals are also one of the common signals in diagnose faults because the signals are rich with information and easy to measure. In this article, we use the relationship between cylinder pressure and instantaneous angular speed to simulate the wave chart of instantaneous angular speed, juxtapose the normal wave with the faulty wave and use the characteristic parameters to diagnose the misfire fault. At the same time, we use BP neural network to realize the early warning.