Improved lubricant compositions for internal combustion engines.

摘要

In accordance with the present invention, there are provided low sulfated ash lubricating oil compositions which comprise an oil of lubricating viscosity as the major component and as the minor component (A) at least about 3 wt% of at least one ashless nitrogen- or ester-containing dispersant, (B) at least about 2 wt% of at least one sulfurized alkyl phenol, and (C) at least one metal dihydrocarbyl dithiophosphate wherein the hydrocarbyl groups contain an average of at least 6 carbon atoms, and wherein the lubricating oil is characterized by a total sulfated ash (SASH) level of from 0.01 to about 0.6 wt% and by a SASH:dispersant wt:wt ratio of from about 0.01 to about 0.2:1.