Disclosed is the use of a lubricating composition including at least one base oil and at least one polyalkylene glycol (PAG) produced by polymerisation or copolymerisation of alkylene oxides including between 3 and 8 carbon atoms, at least one of which being a butylene oxide, for preventing or reducing pre-ignition in an engine, preferably in a vehicle engine.

The present disclosure concerns engine lubricant compositions including at least one base oil, at least one viscosity index improver polymer and at least one polyalkylene glycol, obtained by polymerization or copolymerization of alkylene oxides comprising from 3 to 8 carbon atoms, including at least one butylene oxide, the quantity of polyalkylene glycol being from 1 to 28% by mass with respect to the total mass of lubricant composition. Using at least one polyalkylene glycol, obtained by polymerization or copolymerization of alkylene oxides including from 3 to 8 carbon atoms, further including at least one butylene oxide in a base oil improves engine cleanliness while not increasing, or indeed while decreasing, the consumption of petrol or diesel fuels by the engine.

The present disclosure concerns engine lubricant compositions including at least one base oil, at least one viscosity index improver polymer and at least one polyalkylene glycol, obtained by polymerization or copolymerization of alkylene oxides comprising from 3 to 8 carbon atoms, including at least one butylene oxide, the quantity of polyalkylene glycol being from 1 to 28% by mass with respect to the total mass of lubricant composition. Using at least one polyalkylene glycol, obtained by polymerization or copolymerization of alkylene oxides including from 3 to 8 carbon atoms, further including at least one butylene oxide in a base oil improves engine cleanliness while not increasing, or indeed while decreasing, the consumption of petrol or diesel fuels by the engine.

An alkylene oxide derivative represented by formula (1), wherein a ratio Mz/Mw of a weight average molecular weight (Mw) and z average molecular weight (Mz) calculated from a chromatogram obtained by gel permeation chromatography measurement of the alkylene oxide derivative satisfies formula (2) below: $\begin{array}{cc}{Z-\left[O-{\left(PO\right)}_a-{\left(PO\right)}_b/\left(EO\right)c\right]-H]}_n& \left(1\right)\end{array}$$\begin{array}{cc}5M_z/M_{w}60& \left(2\right)\end{array}$
where Z, n, PO, EO, a, b and c are as defined herein; a+b+c10, and b/c=1/55/1; (PO).sub.b/(EO).sub.c indicates that PO and EO are randomly added; and a random ratio x of PO and EO satisfies 0.1x1.

An alkylene oxide derivative represented by formula (1), wherein a ratio Mz/Mw of a weight average molecular weight (Mw) and z average molecular weight (Mz) calculated from a chromatogram obtained by gel permeation chromatography measurement of the alkylene oxide derivative satisfies formula (2) below: $\begin{array}{cc}{Z-\left[O-{\left(PO\right)}_a-{\left(PO\right)}_b/\left(EO\right)c\right]-H]}_n& \left(1\right)\end{array}$$\begin{array}{cc}5M_z/M_{w}60& \left(2\right)\end{array}$
where Z, n, PO, EO, a, b and c are as defined herein; a+b+c10, and b/c=1/55/1; (PO).sub.b/(EO).sub.c indicates that PO and EO are randomly added; and a random ratio x of PO and EO satisfies 0.1x1.

The invention provides lubricating composition comprising: an oil of lubricating viscosity, and an oxyalkylated hydrocarbyl phenol, wherein the oxyalkylated hydrocarbyl phenol is substituted with at least one aliphatic hydrocarbyl group of 40 to 96 carbon atoms, and wherein the oxyalkylated hydrocarbyl phenol is substantially free of aromatic hydrocarbyl groups. The invention further relates to a method of lubricating a mechanical device (such as an internal combustion engine) with the lubricating composition. The invention further relates to the use of the oxyalkylated hydrocarbyl phenol in the lubricating composition to a passenger car internal combustion engine at least one of (i) control of fuel economy, (ii) control of corrosion, (iii) cleanliness, and (iv) control of bore wear.

A refrigeration cycle apparatus including a refrigeration circuit, the refrigeration circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve, wherein a refrigerant is sealed within the refrigeration circuit, the refrigerant contains trifluoroiodomethane, the compressor is filled with a refrigerator oil, and the refrigerator oil contains at least one of a first compound represented by the following chemical formula 1 and a second compound represented by the following chemical formula 2: ##STR00001##

A refrigeration cycle apparatus including a refrigeration circuit, the refrigeration circuit including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve, wherein a refrigerant is sealed within the refrigeration circuit, the refrigerant contains trifluoroiodomethane, the compressor is filled with a refrigerator oil, and the refrigerator oil contains at least one of a first compound represented by the following chemical formula 1 and a second compound represented by the following chemical formula 2: ##STR00001##

A lubricant comprising (a) an oil of lubricating viscosity; (b) a polyether of number average molecular weight 1000 to 10,000; said polyether comprising alkylene oxide monomer units, where the alkylene group contains 3 to 6 carbon atoms, and ethylene oxide monomer units; and (c) one or more anti-foam agents, where the lubricant has a sulfated ash content of less than about 0.7 percent, is useful for lubricating a stationary gas engine where the engine drives a compressor and where both the engine and the compressor are lubricated with the same lubricant.

A lubricant composition comprising (a) from 0.1 to 10 percent by weight of one or more polyalkylene glycols (PAG); and (2) one or more ester base oils selected from the group of natural esters, synthetic esters and combinations thereof; wherein the one or more PAG has a molecular weight in the range 1500 to 5000 g/mole, comprises from 10 to 40 percent by weight of units derived from ethylene oxide and from 90 to 60 percent by weight of units derived from propylene oxide; and wherein the one or more PAGs are in the form of block copolymer, reverse block copolymer or combinations thereof is provided. Also provided is a method of enhancing the hydrolytic stability of an ester base oil.