The present invention relates to a method of inhibiting corrosion experienced during use of a base oil or lubricant by the addition of a polyester corrosion inhibitor. More especially, the polyester corrosion inhibitor is the reaction product of an alk(en)yl substituted succinic anhydride wherein the average number of succinic groups per alk(en)yl group is less than 3.0, and at least one polyol. There is also provided a composition comprising such a polyester corrosion inhibitor and use of such a composition as a corrosion inhibitor, as well as a base oil or lubricant comprising such a polyester corrosion inhibitor.

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 lubricant composition includes a base lubricant and a plurality of lubricant additive molecules functioning as precursor molecules to induce tribopolymerization and forming in situ protective tribofilm with desirable robustness and low shear resistance. Each lubricant additive molecule includes one or more surface-active groups attractable to target surface, and a carbon containing component operable connected to the one or more surface active groups. The carbon containing component comprise a carbon ring structure having a high ring strain that is metastable and activatable with a ring-opening reaction. A less stable carbon ring structure is more readily activated to the intermediate state, preferable to form more active fragments. Increasing the adsorption strength further is beneficial to prolonging the residence time of additive molecules on the target surface, thereby facilitating the dissociation of molecules and subsequent polymerization.

A method of lubricating the contact between a first surface coated with a hydrogenous carbon film or coating of type a-C:H, ta-C:H, a-C:H:Me or a-C:H:X, as classified by VDI-Standard VDI 2840 and a second ferrous, preferably steel surface. The method comprises supplying to said contact a lubricating oil composition comprising a major amount of an oil of lubricating viscosity and (a) an oil-soluble or oil-dispersible molybdenum compound in an amount such as to provide between 150 and 1000 ppm by weight of molybdenum to the lubricating oil composition, and (b) between 0.1 and 5% by weight with respect to the weight of the lubricating oil composition of a polymeric organic friction modifier, the organic friction modifier being the reaction product of (i) a functionalised polyolefin, (ii) a polyether, (iii) a polyol and (iv) a monocarboxylic acid chain terminating group.

Disclosed are pour point depressants used in compositions and methods for achieving the cold flow properties of synthetic feedstock derived from plastic.

A polyalkylene glycol-based compound may have formula (1):

##STR00001##

wherein R.sup.1 is a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms; R.sup.2 is a monovalent aromatic hydrocarbon group having 6 to 42 carbon atoms or a hydrogen atom; R.sup.3 is a divalent hydrocarbon group having 2 to 4 carbon atoms; and m is a number in a range of from 1 to 40.

A lubricant composition includes a base lubricant and a plurality of lubricant additive molecules functioning as precursor molecules to induce tribopolymerization and forming in situ protective tribofilm with desirable robustness and low shear resistance. Each lubricant additive molecule includes one or more surface-active groups attractable to target surface, and a carbon containing component operable connected to the one or more surface active groups. The carbon containing component comprise a carbon ring structure having a high ring strain that is metastable and activatable with a ring-opening reaction. A less stable carbon ring structure is more readily activated to the intermediate state, preferable to form more active fragments. Increasing the adsorption strength further is beneficial to prolonging the residence time of additive molecules on the target surface, thereby facilitating the dissociation of molecules and subsequent polymerization.

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.

Disclosed is a lubricating oil composition comprising: a major amount of an oil of lubricating viscosity, and an salicylate compound derived from isomerized normal alpha olefin (NAO) having from about 10 to about 40 carbon atoms, wherein the TBN of the salicylate compound is at least 600 mg KOH/g on an actives basis, and wherein the lubricating oil composition contains from about 0.12 to about 0.17 wt. % of calcium and is substantially free of magnesium. Also provided is a method of lubricating an engine with said lubricating oil composition.

The present invention relates to a lubricated system comprising: a) a component comprising a first surface which is a diamond-like carbon (DLC) surface; b) a component comprising a second surface; and c) a lubricant formulation interposed between the first surface and second surface. The lubricant formulation comprises: i) a base stock; ii) a molybdenum compound; iii) an organic polymer comprising a hydrophobic polymeric sub unit selected from polyesters and functionalised polyolefins and a hydrophilic polymeric sub unit selected from polyethers; and iv) optionally, other additives. The combination of the molybdenum compound and the organic polymer in the lubricant formulation reduces the wear on one or more of the surfaces in the lubricated system when compared with using the molybdenum containing friction modifier alone.