| abstract |
An object of the present invention is to provide a low-sulfur lubricating oil composition excellent in friction reducing effect. A lubricating base oil comprises at least one selected from the group consisting of (A) a phosphorus compound represented by the formula (1) or (2), and a metal salt or an amine salt thereof, based on the total amount of the composition. 0.005 to 0.5% by mass in terms of phosphorus element, and / or (B) 0.05% by mass or less of zinc dithiophosphate in terms of phosphorus element, and (C) Ashless friction adjustment A lubricating oil composition comprising 0.1 to 1% by mass of an agent. (In the formula (1), X 1 , X 2 X 3 represents an oxygen atom or a sulfur atom, and at least two of them are oxygen atoms, and R 1 , R 2 , and R 3 are hydrogen It represents an atom or a hydrocarbon group having 1 to 30 carbon atoms.) (In the formula (2), X 4 , X 5 , X 6 X 7 represents an oxygen atom or a sulfur atom, and at least three of them are oxygen atoms, and R 4 , R 5 and R 6 are , A hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.) [Selection diagram] None |