Patent ID: 7612025
Filing Date: 2009-11-03
Classification: C10M,C10N

Abstract:
1. A lubricating oil composition for an internal combustion engine which comprises a lubricating base oil, (A) an alkali metal or alkaline earth metal salicylate containing at least one type of compound selected from those represented by formula (1) below and/or an overbased or basic salt of the salicylate, (B) a phosphorus-containing anti-wear agent, (C) an ashless dispersant comprising a boron-containing succinimide having a boron/nitrogen mass ratio (B/N) of 0.7 to 1, and (D) an ashless anti-oxidant, as the essential components, and containing boron in an amount of 0.01 to 0.15 percent by mass, phosphorus in an amount of greater than 0.02 to 0.08 percent by mass, and sulfur in a total amount of 0.3 percent by mass or less, based on the total mass of the composition: wherein R 1 and R 2 are each independently hydrogen or a hydrocarbon group having 1 to 40 carbon atoms, which hydrocarbon group may contain oxygen or nitrogen, at least either one of R 1 or R 2 is the hydrocarbon group having 1 to 40 carbon atoms, M is an alkali metal or alkaline earth metal, and n is an integer of 1 or 2 depending on the valence of the metal; wherein Component (A) has a metal ratio of 3 or less and is (A-1) an alkali metal or alkaline earth metal salicylate wherein the component ratio of the monoalkylsalicylate having one secondary alkyl group having 10 to 40 carbon atoms is 85 percent by mol or more and the component ratio of the compound represented by formula (1) wherein R and wherein Component (B) is at least one compound selected from the group consisting of zinc salts of phosphorus compounds represented by formulas (3) and (4): wherein X 1 , X 2 , and X 3 are each independently oxygen or sulfur, and R 5 , R 6 , and R 7 are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms; and wherein X 4 , X 5 , and X 6 are each independently oxygen or sulfur, or one or two of X 4 , X 5 and X 6 are a single bond or a (poly)oxyalkylene group and the other(s) are oxygen or sulfur, X 7 is oxygen, R 8 , R 9 , and R 10 are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, and one or two of R 8 , R 9 , and R 10 is a hydrocarbon group.