Additive Effects on Lubricant Fuel Economy

Bench and engine tests were used to determine the effects of typical lubricating oil components on the fuel economy performance of energy conserving oils. The bench studies identified negative fuel economy effects of zinc dialkyldithiophosphates and positive effects of overbased sulfonates. The Sequence VI dynamometer test quantified viscometric influences on fuel economy; results indicated that SAE 5W-30 oils are not always more fuel efficient than 10W-30 analogs, and that viscosity index improver type has a large impact on fuel economy. These effects were integrated with additive effects on other formulation criteria to design an overall system.