Provided is a mineral base oil that conforms to viscosity grades VG22 to VG100 as defined in ISO 3448 and exhibits a distillation curve with a temperature gradient Δ|DT| of distillation temperature between two points of 2.0 vol % and 5.0 vol % of distillation amount being 6.8° C./vol % or less. A vacuum pump oil containing the mineral base oil is excellent in vacuum characteristics and can conform to viscosity grades VG22 to VG100 as defined in ISO 3448.

The present invention is able to provide a lubricating oil composition for compression refrigerating machine having excellent thermal/chemical stability even when used for a compression refrigerating machine using a saturated fluorinated hydrocarbon refrigerant having a low carbon number and a low global warming potential, by using a refrigerant containing a saturated fluorinated hydrocarbon having from 1 to 3 carbon atoms, which uses, as a base oil, an oxygen-containing organic compound composed of at least one member selected from a polyoxyalkylene glycol, a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol and a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol monoether and a polyvinyl ether, and a polyol ester, each having a hydroxyl value of not more than 15 mgKOH/g.

Lubricating oil compositions may include a base oil, a succinimide compound, and a thioheterocyclic compound. Such compositions may have a sulfur content of 0.10 mass % to 1.00 mass % based on a total amount of the composition. A phosphorus content represented by P in mass % and a sulfated ash content represented by M in mass %, based on the total amount of such compositions, may satisfy any of conditions A to C: condition A: P<0.03, and M<0.3; condition B: P<0.03 and 0.3≦M≦0.6; and condition C: 0.03≦P≦0.06 and M<0.3.

Provided are compositions and their use as dispersant and/or detergent additives for lubricants. The compositions comprise an amine alkoxylate of the formula I: (I) wherein R.sup.1-R.sup.7, R.sup.1′-R.sup.7; x, x′, A, A′ and A″ are as defined herein. ##STR00001##

The present invention provides a refrigerating machine oil comprising, as a base oil, at least one oxygen-containing oil having a carbon/oxygen molar ratio of 2.5 or more and 5.8 or less, wherein the refrigerating machine oil is used with a refrigerant comprising 15% by mass or more of difluoromethane, 15% by mass or more of pentafluoroethane, 15% by mass or more of 2,3,3,3-tetrafluoropropene and 15% by mass or more of 1,1,1,2-tetrafluoroethane based on the total amount of the refrigerant.

The invention provides a lubricating composition containing an aromatic compound and an oil of lubricating viscosity. The invention further relates to the use of the lubricating composition in an internal combustion engine. The invention further relates to the use of the aromatic compound as an antiwear agent.

A lubricating composition for use in the crankcase of an engine comprising (i) a base oil; (ii) one or more organo-molybdenum compounds at a level sufficient to provide from 100 to 1000 ppmw of molybdenum; and (iii) from 0.2 wt % to 5.0 wt %, by weight of the lubricating composition, of one or more organic polymeric friction reducing additives, wherein the one or more organic polymeric friction reducing additives has a molecular weight ranging from 1000 to 30000 Daltons and is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a hydrophobic polymer selected from polyolefins, polyacrylics and polystyrenyls; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers, polyesters, polyamides; c) optionally at least one backbone moiety capable of linking together polymeric sub units; and d) optionally a chain terminating group. The lubricating composition provides improvements in terms of reduced friction and wear, in addition to improved fuel economy performance.

The invention provides a method of lubricating a compression-ignition internal combustion engine with a maximum laden mass over 2,700 kg comprising supplying to the engine a lubricating composition comprising: an oil of lubricating viscosity, a 300 TBN or higher alkaline earth metal sulphonate detergent having a metal ratio of 10 to 40, 0.1 wt % to 4 wt % of a borated polyisobutylene succinimide dispersant, wherein the polyisobutylene from which the borated polyisobutylene succinimide is derived has a number average molecular weight of 550 to 1150, and 0.1 wt % to 6 wt % of a polyisobutylene succinimide, wherein the polyisobutylene from which polyisobutylene succinimide is derived has a number average molecular weight of 1550 to 2500, 0 wt % to 0.2 wt % of a phenolic based detergent, wherein the total amount of soap delivered by the alkaline earth metal sulphonates (typically calcium sulphonate) is 0.4 to 1 wt % of the lubricating composition, and wherein the lubricating composition has a sulphated ash content of not more than 1.5 wt %.

A lubricating oil composition of the invention contains: a base oil; at least one of acid phosphate represented by formulae (1) and (2) below; and an antioxidant.

##STR00001##

In the above formulae: R.sup.1, R.sup.2 and R.sup.3 are alkyl groups; and at least one of R.sup.1 and R.sup.2 has 20 to 30 carbon atoms while R.sup.3 has 20 to 30 carbon atoms.

A lubricating oil including a lubricating oil base stock as a major component; and a mixture of (i) one or more protected lubricating oil additives having a first performance function, and (ii) one or more unprotected lubricating oil additives having a second performance function, as a minor component. The first performance function and the second performance function are the same. The one or more protected lubricating oil additives are inactive with respect to their performance function. The one or more protected lubricating oil additives are converted into one or more unprotected lubricating oil additives in the lubricating oil in-service in an engine or other mechanical component. A method for controlled release of one or more lubricating oil additives into a lubricating oil. A method for improving oxidative stability of a lubricating oil and extending performance life of one or more lubricating oil additives.