The Influence of Soot and Dispersant on ZDDP Film Thickness and Friction

The effect of dispersed soot in engine oils is an increasingly important issue in terms of both engine durability and fuel efficiency. Using carbon black as a soot analogue, a study has been carried out to investigate the main factors that determine the impact of soot on friction and ZDDP film formation in formulated oils. It has been found that dispersed carbon black can rapidly remove ZDDP reaction films by abrasion. However, this removal can be prevented or limited by the choice of an optimal dispersant additive.