Patent ID: 8691739

Claim:
A lubricating oil composition comprising a major amount of a base oil incorporated with 5.2 to 5.9 wt % of a dispersed type polymethacrylate-based viscosity index improver, wherein the base oil has an aniline point of about 107 to 116° C. or higher, and the polymethacrylate-based viscosity index improver has a weight-average molecular weight of about 460,000 and a peak area at a chemical shift between 3.4 and 3.7 ppm in a spectral pattern observed by nuclear magnetic resonance analysis ( 1 H-NMR) that accounts for about 10.5 to 12.6% of the total peak area, wherein shear viscosity at 100° C. of the lubricating oil composition is about 5.1 to 5.4 mPa·s or less and the shear viscosity at 150° C. is about 2.6 mPa·s, and wherein the base oil includes from 40 to 100 wt % hydrocracked mineral oil and from 0 to 60 wt % paraffinic mineral oil based on the total weight of the base oil used in the lubricating oil composition.