Lubricant composition

Abstract

A lubricating oil composition including a base oil (A) containing an olefin-based polymer (A1), a viscosity index improver (B), and an imide-based dispersant (C), in which a first olefin-based polymer (A1-1) having a kinematic viscosity at 100° C. of 3.0 mm2/s or more is contained as the olefin-based polymer (A1), a second olefin-based polymer (A1-2) having a kinematic viscosity at 100° C. of less than 3.0 mm2/s is not contained as the olefin-based polymer (A1), a content of a resin component (B1) derived from the viscosity index improver (B) is 0.01% by mass or more based on a total amount of the lubricant composition, and a content of nitrogen atoms derived from the imide-based dispersant (C) is 0.06% by mass or more based on the total amount of the lubricant composition.

1 . A lubricating oil composition, comprising:
 a base oil (A) containing an olefin-based polymer (A1), a viscosity index improver (B), and an imide-based dispersant (C);   wherein a first olefin-based polymer (A1-1) having a kinematic viscosity at 100° C. of 3.0 mm 2 /s or more is contained as the olefin-based polymer (A1), and a content of the first olefin-based polymer (A1-1) is 30% by mass or more based on a total amount of the base oil (A);   a second olefin-based polymer (A1-2) having a kinematic viscosity at 100° C. of less than 3.0 mm 2 /s is not contained as the olefin-based polymer (A1), or is contained in a content of less than 18.5% by mass based on the total amount of the base oil (A);   a content of a resin component (B1) derived from the viscosity index improver (B) is 0.01% by mass or more based on a total amount of the lubricating oil composition;   a content of nitrogen atoms derived from the imide-based dispersant (C) is 0.06% by mass or more based on the total amount of the lubricating oil composition; and   a content ratio of the resin component (B1) derived from the viscosity index improver (B) and the first olefin-based polymer (A1-1) [(B1)/(A1-1)] is more than 0.001 in terms of a mass ratio;   wherein the lubricating oil composition has a kinematic viscosity at 100° C. that is 5.0 mm 2 /s or more and less than 7.1 mm 2 /s; and   an aniline point that is 95° C. or higher.   
     
     
         2 : The lubricating oil composition according to  claim 1 , wherein the base oil (A) contains at least one oil selected from the group consisting of a mineral oil (A2) and a synthetic oil (A3), wherein the mineral oil (A2) and the synthetic oil (A3) are different than the first olefin-based polymer (A1-1) and the second olefin-based polymer (A1-2). 
     
     
         3 . The lubricating oil composition according to  claim 2 , wherein a content of the mineral oil (A2) is 50% by mass or less based on the total amount of the base oil (A). 
     
     
         4 : The lubricating oil composition according to  claim 1 , wherein a high-temperature high-shear (HTHS) viscosity at 150° C. is 2.0 mPa·s or more and less than 2.3 mPa·s. 
     
     
         5 : The lubricating oil composition according to  claim 1 , wherein a mass average molecular weight (Mw) of the resin component (B1) is 200,000 or more. 
     
     
         6 . The lubricating oil composition according to  claim 1 , further comprising a metal-based detergent (D). 
     
     
         7 . The lubricating oil composition according to  claim 1 , further comprising zinc dithiophosphate (E). 
     
     
         8 - 9 . (canceled) 
     
     
         10 . A method for lubricating an internal combustion engine using the lubricating oil composition according to  claim 1 . 
     
     
         11 . The method according to  claim 10 , wherein the internal combustion engine is an internal combustion engine equipped with a forced-induction device. 
     
     
         12 . An internal combustion engine powered by the lubricating oil composition according to  claim 1 . 
     
     
         13 . An internal combustion engine equipped with a forced-induction device powered by the lubricating oil composition according to  claim 1 .