Lubricant composition

Abstract

An object of the present invention is to provide a lubricating oil composition which, even while exhibiting an excellent friction reducing effect by combining plural types of molybdenum-based friction modifiers, has excellent high-temperature detergency, oxidation stability and copper corrosion resistance. The object has been achieved by a lubricating oil composition containing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from the group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3); the metal-based detergent (C) contains a sulfur atom; the ash-free dispersant (D) contains a nitrogen atom; the acid value derived from the binuclear molybdenum dithiocarbamate (B1) and the trinuclear molybdenum dithiocarbamate (B2) is less than 0.04 mgKOH/g; the content ratio of a sulfur content (C) derived from the metal-based detergent (C) to a nitrogen content (D) derived from the ash-free dispersant (D), [(C)/(D)] is 0.30 to 0.85 in terms of the mass ratio; and the phosphorus content based on the total amount of the lubricating oil composition is more than 0.04% by mass and less than 0.10% by mass.