Patent ID: 7867955
Filing Date: 2011-01-11
Classification: C10M,C10N

Abstract:
1. A method of reducing the occurrence of ring-sticking in a four-stroke internal combustion engine, which method comprises lubricating the crankcase of such an engine with a multigrade crankcase lubricating oil composition comprising, or made by admixing: (A) a major amount of oil of lubricating viscosity including at least 5 mass %, based on the mass of the oil composition, of mineral oil, and no greater than 25 mass % of Group I, Group II or Group IV oil, or any mixture thereof; and minor amounts of: (B) a non-hydrogenated olefin polymer in an amount of 1 to 15 mass %, based on the mass of the oil composition, said polymer having a number average molecular weight in the range of 100 to 5,000; (C) a dispersant; (D) a metal detergent; (E) one or more other lubricant additive components selected from anti-oxidants, anti-wear agents and friction modifiers; and (F) a viscosity modifier.