| abstract |
Provided is a lubricating oil composition which can meet the demand for such fuel-saving performance as exceeds the fuel-saving performance of a conventional low-viscosity lubricating oil composition. This lubricating oil composition is characterized by: comprising (A) a lube base oil which has a %C A value of 2 or less and in which the kinematic viscosity at 100°C is adjusted to 1.5 to 4.5mm 2 /s and (B) a viscosity index improver which comprises (B1) 1 to 10 mass% of a poly(meth)acrylate having a weight-average molecular weight of 50,000 or less and (B2) 0.1 to 5 mass % of a poly(meth)acrylate having a weight-average molecular weight of 100,000 to 250,000, each mass% being relative to the whole composition; exhibiting, at 80°C, a ratio (Vs/Vk) of high-shear viscosity (Vs: mPa·s) to kinematic viscosity (Vk: mm 2 /s) of less than 1; and having a coefficient of traction of 0.02 or less as determined under the condition of 40°C, average speed of 3.0m/s, slip ratio of 10% and contact pressure of 0.4GPa. |