Lubricating oil composition
AssigneeIdemitsu Kosan Co., Ltd.
InventorHiroshi Oki
Life of this patent
Estimating the term…
Abstract
Provided is a lubricating oil composition containing a base oil (A) and a viscosity index improver (B) and satisfying the following requirements (I) and (II): Requirement (I): a kinematic viscosity at 80° C., V80 of the lubricating oil composition is 11.5 mm2/s or less; Requirement (II): a ratio [V80/T80] of a kinematic viscosity at 80° C., V80 (m2/s) to an oil film thickness measured at a sliding speed of 2.0 m/s, a maximum Hertz pressure of 0.8 GPa, and an oil temperature of 80° C., T80 (nm) of the lubricating oil composition is less than 0.105 ((m2/s)/nm). The lubricating oil composition is excellent in fuel saving properties and anti-wear properties even when it is used in a temperature environment of around 80° C. which is assumed to fall within a range where an engine is practically used.
Claims9
A lubricating oil composition, comprising:
- a paraffinic mineral oil (A1) having a viscosity index of 100 or more and a paraffin content (% CP) of 60 or more;
- and
- a viscosity index improver (B) selected from the group consisting of a polymethacrylate, a dispersion type polymethacrylate, an olefin-based copolymer, a dispersion type olefin-based copolymer, or a styrene-based copolymer and a comb-shaped polymer;
- wherein the lubricating oil composition satisfies requirements (I), (II) and (III):
- Requirement (I):
- a kinematic viscosity at 80° C., V80 of the lubricating oil composition is 11.5 mm2/s or less;
- Requirement (II):
- a ratio [V80/T80] of a kinematic viscosity at 80° C., V80 (mm2/s) to an oil film thickness measured at a sliding speed of 2.0 m/s, a maximum Hertz pressure of 0.8 GPa, and an oil temperature of 80° C., T80 (nm) of the lubricating oil composition is less than 0.105 ((mm2/s)/nm);
- Requirement (III):
- a high-temperature high-shear viscosity (HTHS viscosity) at 80° C. of the lubricating oil composition is from 4.7 to 7.6 mPa·s.
Dependencies are inferred from the claim text.