Patent ID: 8420583

Claim:
A lubricating oil composition for lubricating an internal combustion engine comprising: a major amount of oil of lubricating viscosity; and a minor amount of at least one highly grafted, multi-functional olefin copolymer made by reacting an acylating agent with an olefin copolymer comprising a copolymer of ethylene and one or more C 3 -C 23 alpha olefins having a number average molecular weight greater than about 10,000 up to about 50,000 in the presence of a free radical initiator to provide an acylated olefin copolymer having a degree of grafting (DOG) of the acylating agent on the olefin copolymer of from above about 1.5 to about 3.0 wt. %, and reacting the acylated olefin copolymer with a mixture of aliphatic and aromatic amines to provide the highly grafted, multi-functional olefin copolymer, wherein the aromatic amine in the mixture of amines comprises from about 40 to about 75 percent by weight of the total weight of the mixture of amines and the aliphatic amine in the mixture comprises from about 25 to about 60 percent by weight of the total weight of the mixture of amines.