The Effect of Added Rotation on Crosshead Bearing Performance

Abstract

Crosshead bearings in two stroke engines operate under severe conditions of lubrication since the sliding velocity of the bearing parts is very low and oscillatory. A computational model is developed to find the effect of intermittently increasing the speed of rotation by indexing the pin through a few degrees of rotation at some part of the 360 deg cycle. It is found that the best position for added rotation is at bottom dead center and that the improvement in minimum film thickness is approximately proportional to the amount of extra rotation. Quite small amounts of pin indexing (ten degrees) can produce a worthwhile increase in film thickness.