Provided herein are compositions comprising at least one estolide compound of formula: ##STR00001##
in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R.sub.1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R.sub.2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R.sub.3 and R.sub.4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided are uses of the compositions described herein.

A lubricant composition includes a lubricating base oil, a controlled release friction modifier, a dispersant, a viscosity modifier and a cleanliness booster. The controlled release friction modifier is an ashless, dispersant-stabilized, borated controlled release friction modifier including an ionic tetrahedral borate compound including a cation and a tetrahedral borate anion, wherein the tetrahedral borate anion includes a boron atom having two bidentate di-oxo ligands of C.sub.18 tartrimide.

A lubricant composition includes a lubricating base oil, a controlled release friction modifier, a dispersant, a viscosity modifier and a cleanliness booster. The controlled release friction modifier is an ashless, dispersant-stabilized, borated controlled release friction modifier including an ionic tetrahedral borate compound including a cation and a tetrahedral borate anion, wherein the tetrahedral borate anion includes a boron atom having two bidentate di-oxo ligands of C.sub.18 tartrimide.

A lubricating oil composition with enhanced deposit control capability is disclosed for engines operating under sustained high load conditions, such as natural gas engines and low-speed or medium-speed diesel engines. The composition comprises (a) a first base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100? C. of from 8.5 to 15 mm.sup.2/s; and (b) a second base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100? C. of from 4.0 to less than 8.5 mm.sup.2/s; wherein the weight ratio of the first base oil component to the second base oil component is in a range of from 1:10 to 1:1.15.

A lubricating oil composition with enhanced deposit control capability is disclosed for engines operating under sustained high load conditions, such as natural gas engines and low-speed or medium-speed diesel engines. The composition comprises (a) a first base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100? C. of from 8.5 to 15 mm.sup.2/s; and (b) a second base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100? C. of from 4.0 to less than 8.5 mm.sup.2/s; wherein the weight ratio of the first base oil component to the second base oil component is in a range of from 1:10 to 1:1.15.

Provided are a viscosity modifier for lubricating oils for obtaining an additive composition for lubricating oils having excellent fluidity in a wide temperature range from low temperature to high temperature; and said additive composition for lubricating oils. Further provided are a viscosity modifier for lubricating oils for obtaining a lubricating oil composition capable of reducing viscosity in good balance in a wide temperature range from low temperature to high temperature; and said lubricating oil composition. The viscosity modifier for lubricating oils includes an ethylene -olefin copolymer (A) which includes 30 to 50 mole % of structural units derived from at least one -olefin selected from -olefins having 4 and 5 carbon atoms and 50 to 70 mole % of structural units derived from ethylene (with the proviso that the total of all structural units of said copolymer is 100 mole %) and which satisfies specific requirements (a), (b), and (c).

Provided are a viscosity modifier for lubricating oils for obtaining an additive composition for lubricating oils having excellent fluidity in a wide temperature range from low temperature to high temperature; and said additive composition for lubricating oils. Further provided are a viscosity modifier for lubricating oils for obtaining a lubricating oil composition capable of reducing viscosity in good balance in a wide temperature range from low temperature to high temperature; and said lubricating oil composition. The viscosity modifier for lubricating oils includes an ethylene -olefin copolymer (A) which includes 30 to 50 mole % of structural units derived from at least one -olefin selected from -olefins having 4 and 5 carbon atoms and 50 to 70 mole % of structural units derived from ethylene (with the proviso that the total of all structural units of said copolymer is 100 mole %) and which satisfies specific requirements (a), (b), and (c).

Provided herein are compositions comprising at least one estolide compound of formula:

##STR00001##

in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R.sub.1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R.sub.2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R.sub.3 and R.sub.4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided are uses of the compositions described herein.

A lubricant composition may be of use in lubrication of an internal combustion engine. A method of utilizing such a lubricant composition may include: lubricating an internal combustion engine using a lubricant composition comprising: from about 30.0 mass % to about 99.8 mass % of an oil base stock, based on a total mass of the lubricant composition, the oil base stock comprising at least one polyol ester; and from 1.0 mass % to 30.0 mass % polyisobutylene, based on a total mass of the lubricant composition; and combusting a fuel in the internal combustion engine.

The lubricating oil composition for four-stroke cycle engine of the present invention includes a base oil (A) and from 0.5 to 10% by mass of a polyolefin (B) having at least an isobutene-derived constituting unit and having a number average molecular weight of 500 to 10,000, with a sulfated ash content being from 0.3 to 1.2% by mass.