In the field of lubricating compositions for motor vehicles, there is disclosed a lubricating composition of a grade according to the SAEJ300 classification defined by the formula (X) W (Y) wherein X represents 0 or 5 and Y represents an integer ranging from 4 to 20. This lubricating composition includes at least one polyalphaolefinic oil (PAO), from 10 to 80% by weight of the composition of at least one oil of group V and at least one comb polymer. Also isclosed is the use of this lubricating composition for improving the Fuel Eco (FE) of a lubricant or for reducing the fuel consumption of an engine, in particular a motor vehicle engine, notably a motor of a hybrid vehicle.

The lubricating oil composition for a refrigerator of the present invention is used with a refrigerant containing carbon dioxide, and contains a base oil (A) containing a polyoxyalkylene glycol as a major component, and an alcohol (B) having at least one hydroxy group, in which a total number of the hydroxy group and an ether bond is from 2 to 3 (provided that the number of an ether bond may be 0).

A lubricant contains alcohol initiated propylene oxide homopolymer, an oil soluble polyalkylene glycol other than the alcohol initiated propylene oxide homopolymer, and a calcium salt of dinonylnaphthalene sulphonate where the lubricant is further characterized by containing less than ten weight-percent of polyol esters based on total lubricant weight is useful as a lubricant for compressors.

A lubricant contains alcohol initiated propylene oxide homopolymer, an oil soluble polyalkylene glycol other than the alcohol initiated propylene oxide homopolymer, and a calcium salt of dinonylnaphthalene sulphonate where the lubricant is further characterized by containing less than ten weight-percent of polyol esters based on total lubricant weight is useful as a lubricant for compressors.

Compositions, methods, systems, and applications herein are directed to lubricant blends that balance solubility and viscosity of a refrigerant, where in some cases the lubricant blends herein help reduce solubility of a refrigerant. A lubricant blend includes a mixture of two or more different types of lubricants to reduce refrigerant solubility.

The refrigerating machine oil according to the present invention comprises a polyalkylene glycol represented by the following formula (1):
R.sup.1(OR.sup.3).sub.nOR.sup.2(1)
[R.sup.1 and R.sup.2 may be the same or different from each other and each represent a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R.sup.3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 2500] the polyalkylene glycol having a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.15, the refrigerating machine oil being used with a mildly flammable hydrofluorocarbon refrigerant.

A fluid contains a base oil consisting of an alcohol-initiated polyalkylene glycol where polyalkylene glycol component is selected from a homopolymer of 1,2-butylene oxide and copolymer of 1,2-butylene oxide and propylene oxide; a glycerol-initiated unsaturated ester that is free of tertiary carbon atoms and quaternary carbon atoms; and an antioxidant.

A fluid contains a base oil consisting of an alcohol-initiated polyalkylene glycol where polyalkylene glycol component is selected from a homopolymer of 1,2-butylene oxide and copolymer of 1,2-butylene oxide and propylene oxide; a glycerol-initiated unsaturated ester that is free of tertiary carbon atoms and quaternary carbon atoms; and an antioxidant.

An antioxidant package composition including a combination of: (i) at least one hindered phenolic antioxidant, and (ii) at least one polyether sulphide; a lubricant composition including: (a) the antioxidant package composition and (b) at least one base oil; a process for preparing the antioxidant package composition; and a process for preparing the lubricant composition.

An antioxidant package composition including a combination of: (i) at least one hindered phenolic antioxidant, and (ii) at least one polyether sulphide; a lubricant composition including: (a) the antioxidant package composition and (b) at least one base oil; a process for preparing the antioxidant package composition; and a process for preparing the lubricant composition.