Patent ID: 8921287

Claim:
A lubricating oil composition comprising a base oil and, on the basis of the total mass of the composition, (A) a calcium sulfonate detergent in an amount of 0.02 to 0.2 percent by mass in terms of metal (MeA); (B) a calcium salicylate detergent in an amount of 0.01 to 0.05 percent by mass, in terms of metal (MeB); and (C) a boron-containing succinimide type ashless dispersant in an amount of 0.005 to 0.02 percent by mass in terms of boron (BoC); (MeB)/(MeA) being 0.05 to 1.0, and (MeA)/(BoC) being from 2.5 to 7.3, wherein the composition further comprises (E) a friction modifier comprising at least one type selected from the group consisting of amine-, amide-, and fatty acid-type friction modifiers in an amount of 0.01 to 5 percent mass and (F) a phosphorus-containing anti-wear agent which is selected from the group consisting of phosphorous acid esters having an alkyl group having 4 to 20 carbon atoms and phosphorous acid esters having an (alkyl) aryl group having 6 to 12 carbon atoms in an amount of 0.01 to 0.06 percent by mass in terms of phosphorous; wherein the base oil is a mixture of (a) a base oil having a kinematic viscosity at 100° C. of 1.5 to 3.5 mm 2 /s and (b) a base oil having a kinematic viscosity at 100° C. of 3.5 to 6 mm 2 /s which are mixed in a mass ratio of (a):(b) of 10:90 to 90:10.