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., V.sub.80 of the lubricating oil composition is 11.5 mm.sup.2/s or less; Requirement (II): a ratio [V.sub.80/T.sub.80] of a kinematic viscosity at 80° C., V.sub.80 (m.sup.2/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., T.sub.80 (nm) of the lubricating oil composition is less than 0.105 ((m.sup.2/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.

The disclosed technology provides lubricating composition comprising: an oil of lubricating viscosity, a p-dodecyl-phenol-free detergent and an oxyalkylated hydrocarbyl phenol, wherein the oxyalkylated hydrocarbyl phenol is substituted with at least one aliphatic hydrocarbyl group of 1 to 250 carbon atoms (or 20 to 220, or 30 to 150 carbon atoms), and wherein the oxyalkylated hydrocarbyl phenol is substantially free of aromatic hydrocarbyl groups. The disclosed technology further relates to a method of lubricating a mechanical device (such as an internal combustion engine) with the lubricating composition. The disclosed technology further relates to the use of the of the lubricating composition in a passenger car internal combustion engine to improve control of at least one of the following (i) fuel economy, (ii) corrosion, (iii) cleanliness, and (iv) bore wear.

A lubricant composition for improving fuel economy of a vehicle having an internal combustion engine includes a base oil and a friction-reducing compound. The friction reducing compound has the following general formula:

##STR00001##

wherein R is an alkyl or alkenyl group having 8 or more carbon atoms, each le is an independently selected hydrocarbon group having 2 to 10 carbon atoms, and n is 1.

[Problem]

From the points of view of improving the fuel efficiency of automobiles and industrial machines and saving energies thereof, the present invention provides lubricants having outstanding shear stability and low-temperature viscosity characteristics.

[Solution]

A lubricant composition includes a lubricant base oil (A) having a kinematic viscosity at 100° C. of 1 to 10 mm.sup.2/s, and an ethylene/α-olefin copolymer (B) in which (B1) the peak top molecular weight is 3,000 to 10,000, (B2) the copolymer shows no melting peak, (B3) the value B is not less than 1.1 and (B4) the kinematic viscosity at 100° C. is 140 to 500 mm.sup.2/s. The lubricant composition has a kinematic viscosity at 100° C. of not more than 20 mm.sup.2/s, a peak top of molecular weight in the range of 3,000 to 10,000, and a weight fraction of components having a molecular weight not less than 20,000 of 1 to 10% relative to all components having a molecular weight not less than the molecular weight that gives the peak top.

A lubricant composition comprises an anti-wear and or/friction modifying additive which is an ester of a fatty acid and a polyol. At least 50% by weight of the additive is in the form of a mono-ester, and is preferably a mono-glyceride. The lubricant composition may be used in an internal combustion engine.

A lubricating oil composition comprising at least 50 percent by mass, based on the mass of the composition of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of a polymer comprising units (a) and one or both units (b) and (c):
—N(COR.sup.1)(CH.sub.2).sub.x—  (a)
—NH(CH.sub.2).sub.y—  (b)
—N(CH.sub.2CH.sub.2-k(CH.sub.3).sub.kCOOR.sup.2)(CH.sub.2).sub.z   (c) where the total number (n) of units (a), (b) and (c) is an integer between 4 and 500; wherein x, y and z are independently 2 or 3; wherein k is zero or 1. The polymer shows good solubility in the lubricating oil and provides friction modification. A method of synthesising a polymer is also disclosed.

An engine oil additive includes carbon nanotubes and boron nitride particulates dispersed within a fluid. The additive is configured to be mixed with a quantity of oil such that the quantity of oil has a concentration from 0.05 to 0.5 grams of carbon nanotubes and of boron nitride particulates per quart of oil to improve the lubricity of the oil. The additive improves the horsepower and torque of the engine while reducing fuel consumption. The carbon nanotubes have an —OH functionalized exterior surface. The carbon nanotubes have a diameter from 1 nanometer to 50 nanometers and have a length from 1 micron to 1000 microns. The boron nitride particulates are hex-boron nitride structures having an average size from 30 nanometers to 500 nanometers.

A lubricating oil composition with high thermal stability, corrosion resistance, and extreme-pressure performance is provided. The present invention have been completed by finding that a lubricating oil composition containing a particular primary aliphatic polysulfide has excellent thermal stability and extreme-pressure performance. A lubricating oil composition containing a base oil and an additive agent, wherein an aliphatic polysulfide constitutes as an additive agent 1% to 10% by mass of the lubricating oil composition, and a primary aliphatic polysulfide constitutes 1% to 50% by mass of the aliphatic polysulfide.

The invention provides a lubricating composition comprising a low viscosity base oil and a synergistic mixture of a functionalized ethylene-α-olefin copolymer, a poly(meth)acrylate polymer, and a metal-free anti-wear agent. The invention also provides a method of lubricating an internal combustion engine using such a lubricating composition.

A compound of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br, and I; X is independently selected from the group consisting of H, F, Cl, Br, and I; Y is independently selected from the group consisting of F, Cl, Br, and I; Z is independently selected from the group consisting of H, F, Cl, Br, and I; n is an integer from 1 to 8; and n′ is an integer from 1 to 12. ##STR00001##