Lubricating oil composition for internal combustion engines (LAW651)
OwnerKatsuya Koganei, Makoto Kanbarainventors
Life of this patent
Estimating the term…
Abstract
A synthetic lubricating oil composition for internal combustion engines, comprises an organomolybdenum compound, a zinc dithiophosphate and a base stock obtained by blending an ester having a kinematic viscosity of from 8 cSt to 35 cSt at 100° C. and a saponification value of 200 mg-KOH/g or smaller with a poly (α-olefin) and/or a highly-refined mineral oil.
Claims7
A lubricating oil composition for internal combustion engines, said composition comprising an ester-blended base stock, an organomolybdenum compound and a zinc dithiophosphate, wherein said ester-blended base stock comprises:
- from 10 wt. % to 30 wt. % based on the whole weight of the base stock of an ester having a kinematic viscosity of from 8 cSt to 35 cSt at 100° C. and a saponification value of 200 mg-KOH/g or lower;
- and
- from 90 wt. % to 70 wt. % based on the whole weight of the base stock of a poly (α-olefin) and/or a highly-refined mineral oil having a sulfur content of 5 ppm or lower and an aromatic hydrocarbon content of 1 wt. % or less.
The lubricating oil composition of claim 1, 3 or 8 wherein the organomolybdenum compound is present in an amount in the range of 100 ppm to 1,000 ppm in terms of molybdenum and the zinc dithiophosphate is present in an amount in the range of 800 ppm to 1,800 ppm in terms of phosphorus.
A method for forming a lubricating oil having a lowered coefficient of friction comprising combining an ester based lubricating oil base stock, an organomolybdenum compound and a zinc dithiophosphate, wherein the ester based lubricating oil basestock is a mixture of a synthetic ester having a kinematic viscosity of from 8 cSt to 35 cSt at 100° C. and a saponification value of 200 mg-KOH/g or less and a poly (α-olefin) and/or a highly refined mineral oil having a sulfur content of 5 ppm or less and an aromatic hydrocarbon content of 1 wt. % or less and wherein said ester comprises 10 to 30 wt. % of said ester based lubricating oil base stock.
Dependencies are inferred from the claim text.