Dynamic analysis of piston slap coupled with connecting rod, crankshaft and engine block

This paper presents the analytical method to evaluate the impact force induced by piston slap considering the dynamic effect of motion and vibration of piston, connecting rod, crank shaft and engine block. The inertia force of connecting rod in vertical, horizontal and rotational direction are taken into consideration and the effects of these inertia forces on the piston impact force and main bearing impact force of crank shaft are discussed comparing with the conventional simulation method in which the inertia force of connecting rod is idealized as the added mass to the piston and crank pin. The difference of the wave form of piston slap force is recognized between the present method and the conventional method. Moreover, influences of motion and vibration of piston and connecting rod upon the crank shaft vibration and main bearing impact force are examined. The effect of the coupled vibration is seen in the wave form of the torsional vibration of the crank shaft and main bearing impact force in the horizontal direction.