Coupling effect between dynamic behavior and lubricating behavior of cylinder-piston system in internal combustion engine

A model was established to analyze the coupling effect between the dynamic behavior and the lubricating behavior of the cylinder-piston system in an internal-combustion engine. Software ANSYS and FORTRAN program were combined to carry out the numerical simulation of the model. Thus the finite element method model of the cylinder was established and its transient dynamic response was computed with the ANSYS software. The lubrication of the cylinder-piston pair was simulated with an average Reynolds equation considering the second-vibration of the piston. The time-dependent minimum film thickness, friction force and friction power loss were calculated by making use of the sequential field-coupling analysis. It was found that the coupling action between the lubricating behavior and the dynamic behavior of the cylinder-piston system had significant effects on the lubricating characteristics as compared with the analytical results excluding the vibration of the cylinder. Namely, in consideration of the cylinder vibration, the cylinder-piston system registered larger friction force, friction power loss and oil film thickness variation.