Lubrication Analysis Coupling With Shaft Dynamics Of Internal-combustion Engine Main Bearing

Internal combustion engine is a typical complex friction system in which the lubrication characteristics of crankshaft-bearing system has a great influence on its dynamic properties. Because of the work characteristics of the internal combustion engine, the crankshaft has a unique dynimic characteristics under complex curved and torsion loading. The crankshaft's dynamic motion and main bearing's lubrication interactions together to achieve stable power output of the engine. At present, most of scholars at home and abroad regards internal combustion engine friction system as shaft dynamics and bearing lubrication separately,coupling analysis of the study also did not fully consider all the loads of engine shaft, a variety of lubrication factors as well. On this basis,the article regards the crankshaft and bearing as a whole system,taking Shantuo 295G diesel engine as an example, establish the virtual prototype model of its shaft system, then the analysis the main bearing lubrication properties United MATLAB and ADAMS dynamics in consideration of the action of the crankshaft dynamics. The main contents are as follows:First of all, summary the fundamental theory of fluid lubrication and the development of the main bearing lubrication of internal combustion engine. The present existing insufficient and problems in the research as shown above. Explicit the research content of this paper:analysis the theoretical basis coupled of main bearing lubrication and shaft dynamics, simulation and analysis the 295G diesel engine.Analysis the feasibility of theoretical analysis about the main bearing lubrication of internal combustion engine with the crankshaft's dynamics. Derived the Reynolds equation of journal misalignment bearing of according to the general form of Reynolds equation, oil film reaction force, the film anti-torque, friction coefficient and oil leakage are also given the numerical integration formula.Introduce steps and methods of numerical calculate of the journal misalignment bearing's Reynolds equation, developing a transient state journal bearing lubrication analysis software of MATLAB on the theory.The funddamental model of internal-combustion engine main bearing lubrication characteristic undering crankshaft dynamics is raised. First, create a virtual flexible model prototype of the internal combustion engine crankshaft in ADAMS, then, create main bearing lubrication analysis module,and assemble "Engine Shaft - Bearing" open-loop feedback control system in Simulink,controlling the virtual prototype real-time at the feedback of open loop control by ADAMS/Controls.Analysis the main loads of flexible crankshaft, and the calculation formula of the different stress are respectively derived.Finally, according to the the above theory with 295G diesel engine, introducing the modeling steps of internal combustion engine main bearing coupling with coupling crankshaft dynamics in detail. The detailed steps as follows:first, establish crankshaft of flexible body model by connection with ANSYS and ADAMS. Then,external load forces are applied to the various parts of flexible crankshaft model, establish the crankshaft motion analysis module by ADAMS/Control.at last, building the "Engine Shaft - Bearing" open-loop feedback control system in Simulink. Performance and simulation the main bearing lubrication of the 295G diesel engine, analysis of the simulation results prove it is feasible that the method of analysis bearing lubrication of internal combustion engine coupling dynamics theory combined MATLAB and ADAMS.