| abstract |
Lubricating oil compositions for internal combustion engines are described 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) from about 0.70 equivalent up to less than one equivalent, per equivalent of acylating agent, of 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, and (C) at least one metal salt of a dihydrocarbyl dithiophosphoric acid wherein (C-1) the dithiophosphoric acid is prepared by reacting phosphorus pentasulfide with an alcohol mixture comprising at least 10 mole percent of iopropyl alcohol and at least one primary aliphatic alcohol containing from about 3 to about 13 carbon atoms, and (C-2) the metal is a Group II metal, aluminum, tin, iron, cobalt, lead, molybdenum, manganese, nickel or copper. |