| abstract |
Lubricating oil compositions for internal combustion engines which comprise (A) a major amount of oil of lubricating viscosity, and minor amounts of (B) at least one carboxylic derivative composition produced by reacting (B-1) at least one substituted succinic acylating agent with (B-2) at least one amine compound characterized by the presence within its structure of at least one HN< group, said acylating agents being characterized by the presence within their structure of an average of at least 1.3 succinic groups for each equivalent weight of substituent groups, (C) at least one basic alkali metal salt of sulfonic or carboxylic acid, and (D) at least one metal salt of a dihydrocarbyl dithiophosphoric acid wherein (D-1) the dithiophosphoric acid is prepared by reacting phosphorus pentasulfide with an alcohol mixture comprising at least 10 mole percent of isopropyl alcohol, secondary butyl alcohol, or a mixture of isopropyl and secondary butyl alcohols, and at least one primary aliphatic alcohol containing from about 3 to about 13 carbon atoms. The oil compositions also may contain (E) at least one carboxylic ester derivative composition, and/or (F) at least one neutral or basic alkaline earth metal salt of at least one acidic organic compound and/or (G) at least one partial fatty acid ester of a polyhydric alcohol. |