Research On Dynamic Effects Of Engine Connecting Rod Bearing

With the development of social economy,it is required to enhance the performance of the engine.Therefore,it is of great significance to accurately analyze the dynamics of the engine connecting rod,consider the lubrication characteristics of the connecting rod bearing to improve the service life of the engine and reduce the energy consumption.Connecting rod plays the role of transferring the combustion pressure in the engine cylinder to the crank to drive the operation of the crankshaft.In the process of power transmission,the connecting rod bearing is an important part of the connecting rod assembly,which directly affects the process of power transmission to the crankshaft.Thus,this dissertation will consider the lubrication characteristics of the connecting rod bearing,and carry out the research on the dynamic effects of connecting rod bearing.A simplified model of the crank slider mechanism was established in combination with an engine,the forces of each component were analyzed,and the differential equation of motion was established.The kinematics and dynamic parameters of the entire mechanism were obtained by solving the simultaneous equation using Runge-Kutta method.For the hydrodynamic lubrication analysis of sliding bearings,there may be some problems such as non-convergence or low accuracy in the calculation of oil film pressure distribution in the existing research.An optimization algorithm is proposed in this dissertation,based on the combination of finite difference and dynamic design variable method.The main thought is take the grid node of the oil film pressure as design variables,in order to meet the difference equation to establish the objective function of each grid node,then the problem of pressure distribution of oil film in bearing is transformed into an unconstrained optimization problem,some non-convergence conditions in existing calculation methods will be solvedFor the solution of the center orbit of connecting rod bearing,this dissertation combines the solution of dynamics and hydrodynamic lubrication,takes the mechanical parameters obtained from the dynamics calculation as the external load of the bearing,obtains the pressure distribution through the optimization algorithm,and then uses the numerical integration method to obtain the oil film reaction force,and establishes the dynamic relationship with the external load.In the process of balancing with the external force,the orbital path of the axis is determined,and the lubrication performance of the bearing during the movement of the connecting rod is mastered.In this dissertation,the dynamic numerical calculation method is combined with the optimization algorithm to solve the oil film pressure of the journal bearing,and the dynamic and lubrication characteristic parameters of the connecting rod are obtained by compiling the Visual Basic 6.0 program.