| abstract |
PROBLEM TO BE SOLVED: To provide a lubricating oil composition which maintains high antiwear properties, and has extremely excellent base number maintenance properties and high-temperature detergency. SOLUTION: The lubricating base oil has a thiophosphate or a metal salt of a phosphoric acid ester represented by the general formula (1), a thiophosphate or a phosphoric acid ester represented by the general formula (2), or a metal thereof. A lubricating oil composition comprising at least one compound selected from the group consisting of salts and amine salts. Embedded image (X 1 of the formula (1), X 2, X 3 and X 4: at least one oxygen atom or a sulfur atom is an oxygen atom, Y1 represents a divalent metal atom; X 11 and of the formula (2) X 12 : an oxygen atom or a sulfur atom, at least one of which represents an oxygen atom, and U represents a proton, a monovalent metal atom or an ammonium ion. |