Effect of surface treatment and lubricant additives on valve train performance

The performance of roller follower valve train depends on the proper rolling of roller on the cam lobe. Slip of rollers may result in increased sliding friction and effects the overall performance of valve train. An advanced roller finger follower valve train was used to study the effects of roller surface treatment, oil additives and their combined effects on roller slip and the valve train performance. Improved lubrication film was observed at cam-roller mating due to micro dimples on the roller outer race due to Wonder Process Craft (WPC) surface treatment. WPC surface treated rollers exhibited lesser roller sliding as compared to non-treated pure steel rollers. The synthetic oil reduced the roller slip and friction in contrast to the mineral oil. The combination of WPC treated rollers with friction modifier oil resulted in the reduced roller slip and improved valve train efficiency.