摘要 |
A diesel engine operating on a fuel containing from about 5 to about 100 wt. % bio-diesel components and being lubricated with a lubricating oil composition including a major amount of oil of lubricating viscosity, and a minor amount of at least one highly grafted, multi-functional olefin copolymer. The olefin copolymer is made by reacting an acylating agent with an olefin copolymer having a number average molecular weight greater than about 1,000 in the present 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 at least 0.5 wt. %, and reacting the acylated olefin copolymer with an amine to provide the highly grafted, multi-functional olefin copolymer. As used, the highly grafted, multi-functional olefin copolymer is effective to reduce a viscosity increase in the lubricating oil composition for the engine. |