abstract |
To provide a lubricating oil composition capable of improving lubricating performance in a diesel engine provided with an exhaust gas recirculation (EGR) device. A lubricating oil composition having a sulfur content of less than about 0.3% by weight comprising: (a) a large amount of oil of lubricating viscosity; and (b) a small amount of one or more (i) monovinyl aromas. A copolymer of an aromatic hydrocarbon hydrogenated polymer and a conjugated diene polymer, wherein the hydrogenated polymer portion of the monovinyl aromatic hydrocarbon is at least about 20% by mass of the copolymer, (ii A high molecular weight polymer comprising a) an olefin copolymer containing an alkyl or arylamine or amide group, a nitrogen-containing heterocyclic group or an ester bond, and / or a derivative of an acrylate or alkyl acrylate copolymer having a dispersing group; (C) a neutral and / or overbased phenate detergent that can be provided to the lubricating oil composition at a rate of about 6 to about 50 mmol of phenate surfactant per kg of final oil. In the lubricating oil composition comprising a phenate detergent, the lubricating oil composition in the lubricating oil composition that contains a salicylate surfactant of less than 1mmol per finished oil 1 kg. [Selection figure] None |