| abstract |
A lubricating oil composition has a major amount of an oil of lubricating viscosity, a minor amount of a carbonated sulfurized metal alkyl phenate and, a minor amount of a carbonated metal alkyl aryl sulfonate. The total base equivalents donated by the phenate is more than 85% of the total base equivalents donated by the phenate and sulfonate. The composition also has alkenyl or alkyl succinimide additives that are the reaction product of a high molecular weight alkenyl- or alkyl-substituted succinic anhydride and a polyalkylene polyamine having an average of greater than four nitrogen atoms per mole, wherein the reaction product is post-treated with a cyclic carbonate. |