FUEL-EFFICIENT ENGINE OIL COMPOSITION

摘要

The present invention provides am engine oil composition with excellent fuel saving properties, which comprises a lubricating base oil with a saturate content of 70 percent by mass or more and a viscosity index of 90 or greater and a star polymer as a viscosity index improver in an amount of at least 4 percent by mass or more on the basis of the total mass of the engine oil composition, the ratio (B/A) of (B) the high temperature high shear viscosity at 1 x 10 7 /s shear rate and 100ºC to (A) the high temperature high shear viscosity at 1 x 10 6 /s shear rate and 100ºC being 0.85 or less.