Research On The Scuffing Fault Diagnosing Considering The Particle Effect

The operating condition of modern diesel engines continues to become more severe andpistons are more likely to expose to scuffing fault.Its short-term occurrence make the on-line diagnosishard to identify,but once it happens the harm is serious to the diesel engine.Therefore,it is very important to study the mechanism of scuffing fault and the online diagnosis method.The scuffing fault is mainly caused by the failure lubrication of piston rings,so in this study the effects of solid particles on the piston rings' lubrication was investigated based on the traditional model,and the relationship between friction force of piston rings andtorsional vibration of shaftas well as that between friction force of piston rings and vibration was studied in order to find method to diagnose the scuffing fault.The following contents are involved.Based on the average Reynolds equation,the liquid-solid biphase lubrication model was established by introducing single particle contact,multi particle contact,particle bearing capacity,and effect of particle effects on viscosity and particle causing friction force.The liquid-solid biphase lubrication model is verified by using high speed reciprocating friction machine,by comparing the friction force measured experimentally and that calculated by the present model in this study and the traditional model.It is found that friction force calculated by the established model is more close to the measured friction force.The effects of particle diameter,particle concentration,particle yield strength,particle density,particle elastic modulus and Poisson's ratioon the lubrication performance of piston ring was studiedThe scuffing fault test was carried out,and shaft torsionalvibrationand machine surface's vibrationwere studied under the scuffing fault condition.Finally the relationship between friction force and shaft torsional vibration was fond,as well as the relationship between friction force and machine surface's vibration.Thereforethe scuffing fault of diesel enginecan be diagnosedthrough this relationship.Besides the friction force under different conditions were obtained through the method of Load identification which means different lubrication conditions of piston ringscan be separated.Therefore this method can also be used to diagnose the scuffing fault.