A lubricant composition of an oil of lubricating viscosity; an esterified copolymer with a backbone comprising units derived from (i) an α-olefin monomer of at least about 6 carbon atoms and (ii) an ethylenically unsaturated carboxylic acid in a mole ratio of 1:3 to 3:1; and a polymer comprising olefin monomer units of 3 to 5 carbon atoms, wherein at least 50 percent by weight of such units contain fewer than 6 carbon atoms and wherein less than 5 percent by weight of such units are ethylene monomer units; exhibits good power transfer efficiency and elastohydrodynamic film thickness.

[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 comprising an oil of lubricating viscosity and 0.01 to 5 percent by weight of a substantially sulfur-free alkyl phosphate amine salt, where at least 30 mole percent of the phosphorus atoms are in an alkyl pyrophosphate salt structure, exhibits good antiwear performance. In the phosphate amine salt, at least 80 mole percent of the alkyl groups are typically secondary alkyl groups of 3 to 12 carbon atoms.

The present invention relates to the use of a lubricating composition comprising: —at least one base oil; and—at least one monoester which is separate from the base oil and formed between a linear, saturated or unsaturated C.sub.8-C.sub.14 monocarboxylic acid, and a branched, saturated or unsaturated C.sub.4-C.sub.16 monoalcohol to reduce the fuel consumption of a vehicle fitted with a transmission member, in particular a gearbox and/or an axle, which is lubricated by means of said composition.

The disclosed technology relates to a lubricant composition for automotive gears, axles and bearings, the lubricant composition containing an oil of lubricating viscosity and a metal thiophosphate compound, such as zinc dialkyldithiophosphate, as well as a method of obtaining extreme pressure performance in automotive gears, axles and bearings at lower sulfur content than is typical, by lubricating such automotive gears, axles and bearings with a lubricant composition containing a metal thiophosphate compound, such as zinc dialkyldithiophosphate.

The present invention relates to the use of a lubricating composition comprising: -at least one base oil; and -at least one monoester which is separate from the base oil and formed between a linear, saturated or unsaturated C.sub.8-C.sub.14 monocarboxylic acid, and a branched, saturated or unsaturated C.sub.4-C.sub.16 monoalcohol to reduce the fuel consumption of a vehicle fitted with a transmission member, in particular a gearbox and/or an axle, which is lubricated by means of said composition.

Lubricant compositions comprising (a) an oil of lubricating viscosity and (b) a phosphonate ester other than a zinc salt. The phosphonate ester may be the reaction product of (i) phosphonic acid or a monomeric ester thereof with (ii) a propanediol having hydroxy groups in both the 1 and 3 positions and one or more of the carbon atoms of the propyl units are substituted with one or more alkyl groups such that the total number of carbon atoms in the propanediol ranges from 4 to 12. The molar ratio of (i) to (ii) may be 0.9:1.1 to 1.1 to 0.9.

A transmission fluid composition contains a major amount of a lubricating oil basestock, and a minor amount of an additive package comprising: (i) a mixture comprising two or more phosphites and/or phosphates; (ii) one or more thioester compounds; (iii) one or more zinc dihydrocarbyl dithiophosphate compounds; and (iv) one or more oil-soluble or dispersible molybdenum-containing compounds. Such a transmission fluid may be used for controlling and/or reducing wear, e.g., in a manual transmission.

A lubricant composition of an oil of lubricating viscosity, a grafted copolymer viscosity modifier that is an ashless condensation reaction product of an olefin polymer, having a number average molecular weight of about 1000 to about 10,000, comprising carboxylic acid or equivalent functionality grafted onto the polymer backbone, with a monoamine or a polyamine often having a single primary amino group, which exhibits good dispersancy and viscometric performance in a driveline device.

The instant disclosure relates to hydrocarbyl- (e.g., alkyl-) benzene sulfonate detergents and their salts, where the hydrocarbyl group includes moieties equivalent to 5 to 10 carbon branched polyene compounds. Such compounds and their salts are useful as lubricant additives. The detergents disclosed herein may solve at least one problem of providing anti-wear performance, frictional performance, oxidation performance, viscosity performance, and detergency.