| abstract |
The present invention provides a lubricating oil composition, which is capable to maintain sufficient low-friction (i.e. fuel saving performance) even when the lubricating oil is contaminated with soot and metal abrasion powder, which is excellent in durability with regard to anti-wear property and detergency, as well as oxidation stability, and which is capable to lower the ash content and to sufficiently maintain the performance of exhaust-gas after-treatment device for a long term. The lubricating oil composition comprises a lubricant base oil containing a base oil (X) of which % C P is 70 or more, % C A is 1 or less, viscosity index is 115 or more, and CCS viscosity at −35° C. is 3000 mPa·s or less, wherein the lubricant base oil, to total mass of the composition, contains following components (A)˜(D): n (A) 0.01˜10 mass % of ashless friction modifier; n (B) 0.01˜0.2 mass % of phosphorus-containing anti-wear agent as phosphorous content; n (C) 0.01˜1 mass % of metallic detergent as metal content; and n (D) 0.01˜0.4 mass % of ashless dispersant having 3000˜20000 of weight-average molecular weight as nitrogen content. |