Low ash 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 2 wt % of at least one ashless nitrogen- or ester-containing dispersant, (B) an antioxidant effective amount of at least one oil soluble antioxidant material, and (C) at least one oil soluble dihydrocarbyl dithiophosphate antiwear material wherein the hydrocarbyl groups contain an average of at least 3 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 wt:dispersant wt ratio of from about 0.01 to about 0.2:1.