METHOD FOR IMPROVING ENGINE FUEL EFFICIENCY

摘要

A method for improving fuel efficiency, while maintaining or improving wear protection, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil having a HTHS viscosity of less than 2.6 cP at 150° C. In one form, the formulated oil has a composition that includes a lubricating oil base stock as a major component, and zinc dialkyl dithio phosphate, a mixture of (i) at least two alkali metal detergents, (ii) at least two alkaline earth metal detergents, or (iii) one or more alkali metal detergents and one or more alkaline earth metal detergents; and a viscosity index improver, as minor components. The lubricating oil has a HTHS viscosity of less than 2.6 cP at 150° C. The composition contains less than 2 weight percent of the viscosity index improver, based on the total weight of the formulated oil or lubricating engine oil.