| abstract |
A lubricating oil formulation is described which is useful in internal combustion engines. More particularly, lubricating oil compositions for internal combustion engines are described with comprise (A) a major amount of oil of lubricating viscosity, and minor amounts of (B) at least one carboxylic derivative com-position produced by reacting (B-l) at least one substi-tuted succinic acylating agent with (B-2) from one equiv-alent up to about 2 moles, per equivalent of acylating agent, of at least one amine compound characterized by the presence within its structure of at least one HN< group, and wherein said substituted succinic acylating agent consists of substituent groups and succinic groups wherein the substituent groups are derived from a poly-alkene, said polyalkene being characterized by an Mn value of about 1300 to about 5000 and an Mw/Mn value of about 1.5 to about 4.5, 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 partial fatty acid ester of a polyhydric alcohol, 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, and (D-2) the metal is a Group II metal, aluminum, tin, iron, cobalt, lead, molybdenum, manganese, nickel or copper. 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. In one embodiment, the oil compositions of the present invention contain the above additives in amounts sufficient to enable the oil to meet all the performance requirements of API Service Classification identified as "SG", and in another embodiment the oil compositions of the invention will contain the above additives and other additives described in this application in amounts sufficient to enable the oils to satisfy the requirement of the API Service Classification identified as "CE". |