MARINE DIESEL ENGINE FAULT DIAGNOSIS BASED ON VIBRATION MONITORING

Timely diagnosis of incipient malfunctions of diesel engines is desirable for avoiding costly unanticipated shutdown as well as preventing severe damage to the engine. The fault diagnosis of marine diesel engine based on vibration monitoring is investigated in this paper. The characteristics of the exciting sources of engine surface vibration and the features of piston impacts are described, the properties of engine surface vibration signals under different working conditions are discussed, and some criteria suitable for marine diesel engine vibration monitoring and fault diagnosis are presented. The analytic and experimental results show that the principal exciting source of cylinder block surface vibration is the piston impact. The changes of vibration character parameters of cylinder block can be used to diagnose the variations in cylinder liner clearance and the conditions of the components inside the cylinders. The relationships between the character parameters of surface vibration and the working conditions of cylinder liner, crankpin and main bearings are presented and discussed. Experimental investigations were carried out on a medium speed four-stroke turbo-charged main diesel engine while the ship was in operation. The results show that it is effective to detect the working conditions of the components inside the cylinders of diesel engine based on surface vibration signal monitoring.