| abstract |
The present invention provides a lubricating oil composition having excellent NOx resistance, anti-oxidation properties, base number retainability and detergency, suitably used for an internal combustion engine. The lubricating oil composition comprises a lubricating base oil, (A) a 2,2,6,6-tetraalkylpiperidine derivative and (B) an organic molybdenum compound and/or an organic tungsten compound and preferably further comprises (C) a hindered phenol-type anti-oxidant and/or an aromatic amine-type anti-oxidant or (D) at least one type of compound selected from the group of consisting of phosphorus compounds and metal salts or amine salts. Furthermore, the present invention also provides a method for lubricating a sliding material by contacting a specific lubricating oil composition selected from the above lubricating oil compositions with the sliding material while preventing elution of the copper and lead contained in the material. |