Research On The Mechanism Of The Gap Failure Of Diesel Engine Working Components And The Self-healing Of The Coupling Misalignment Failure

In engineering practice,piston engine clearance faults are often caused by serious wear and tear or improper replacement.Many studies on the dynamics characteristics of connecting rod mechanisms considering clearance and component flexibility have not taken into account the working characteristics and mechanical characteristics of the engine,and the influence rules of the abnormal clearance of the engine connection pair on the oil film and vibration response under complex and variable working conditions are still not clear.At the same time,it is necessary to establish a high-precision model of connecting rod bearing with clearance in order to use the data-driven method to predict the clearance faults of engine connecting rod bearing.In this paper,the coupling characteristics of different types of clearance faults with other faults are revealed,and the hazards of clearance faults are quantitatively analyzed through fatigue and life of key contact surfaces.(1)Establish a high-precision dynamics simulation model for a diesel engine.First to establish a three-dimensional model of actuator components and parts flexibility,secondly expounds the theory of flexible body dynamics simulation process and the key modeling element,the mathematical model and finally by considering the driving mode,the flexible body parts just flexible and modal order number,that should be considered under different circumstances were analyzed,and the results have high precision and low time cost is compatible with the dynamics simulation model.(2)Considering the independent clearance faults of the connecting rod big-end bearing,small-end bearing and cylinder liner,the simulation is carried out for the clearance faults of different degrees under the separate clearance faults.With the increase of clearance,the oil film state and vibration intensity increase,and are significantly affected by the operating conditions.The failure test of the connecting rod bearing bush proves that the clearance of the bearing bush directly affects the vibration of the moving mechanism in the phase section of the specific angular domain.It lays a foundation for analysis of key clearance fault and vibration fault monitoring of diesel engine.(3)To solve the problem that the actual clearance faults of the unit are not independent clearance faults,the coupling research of clearance faults and other faults is carried out.Based on cylinder liner clearance failure,the first analysis of the piston force to offset the influence degree of the failure of clearance failure,next analyze many clearance fault offset and piston force coupling dynamic response,finally,the coupling fault quantitative analysis was carried out on the fatigue life of key components of the junction surface,to the actual unit on the sidelines of the coupling fault monitoring research lay the foundation.(4)aiming at problems in shaft system is wrong,to carry out the shafting self-healing of fault in the experimental study,through the sensor layout and parameter calculation for information,through the six degrees of freedom in experimental platform to achieve the process,get to the state and the static measurement,since the results more effective and reliable,and for the engine shafting self-healing of the feasible solutions are put forward.