Finite Element Study on Piston Assembly Dynamics in Multicylinder Internal Combustion Engine 2011-01-1075

The paper presents results of the multibody non linear dynamic analysis of the internal combustion engine to study the motions of the piston assembly components like piston, piston rings etc. The complete three dimensional CAD model of the multicylinder engine is developed using UG-Nx-3 modeling software and the finite element model along with the required boundary conditions to mimic the working conditions of the engine is obtained using HYERMESH preprocessor. The effect of hydrodynamic lubrication is imposed by solving Reynolds equation. The complete model is simulated using L.S.Dyna software and the results of simulation are used to study the dynamic phenomenon of the piston assembly components. The dynamic motions of the top, second, oil rings are demonstrated and it is found that there exists a difference in ring motions in different cylinders of the same engine. The results show that the piston tilt changes the sign during the operating cycle and also at top and bottom dead centers. The tilt of the pistons in cylinder land 2 are in opposite direction at the same crank angles. But the tilt of the pistons in cylinder 1 and 4 are almost same in magnitude and direction at the same crank angle. This new method adopted to study the piston assembly component dynamics can help the engine designer in the initial stages of the engine design where he needs to test number of design alternatives, which is difficult and time consuming if done experimentally