Search

In roller follower valve train, proper rolling of roller reduces the chances of fatigue failure and power losses. During engine operation, the roller does slip on the camshaft surface. The oil film thickness plays an important role on the roller sliding which necessitates experimental investigations. A modern gasoline engine valve train has been instrumented using advanced sensors for real time measurement of oil film thickness and roller slip, simultaneously. Rise in oil film thickness at cam/roller interface increased the tendency of roller slip. Drag due to shear of lubricant and rise in contact loading at very high camshaft speeds resulted in reduction of roller sliding. Presence of anti-wear agents and friction modifiers increased the tendency of roller sliding. • Modern engine valve train has been instrumented using advanced sensors for real time monitoring of oil film thickness and roller sliding. • Rise in oil film thickness increased the tendency of roller slip due to weak traction force. • Drag due to shearing of oil film and rise in contact loading resulted in reduction of roller sliding. • Presence of anti-wear agents and friction modifiers increased the tendency of roller sliding. • At elevated temperature and high operating speed, viscosity index improvers helped to reduce the roller sliding. [ABSTRACT FROM AUTHOR]