Dynamic Responses of Clearance Induced Impacts in Big End Bearing Condition Monitoring of Diesel Engines

Enlarged clearance in connecting rod big end bearing is known to be a typical fault in internal Combustion (IC) engines such as diesel engines. Enlarged clearance causes inefficient operation that leads to reduced performance of the engine. In this work, the influence of enlarged clearances in big end bearing on the vibration of the system is studied. The kinematics and dynamics of the big end bearing were explored using numerical simulation to investigate the effect of the clearance on the associated response of acceleration signals obtained by multiply the simulated bearing forces with frequency response function (FRF). Different clearance and engine speed conditions were simulated for analysis of various degree of bearing clearance fault. Results obtained for these cases are evaluated for vibration analysis which shows that simulation model developed is able to simulate the vibration signals issuing from the dynamics of engine system with various clearance phenomenon.