The use of a complex ester obtainable by esterification reaction between aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acids, aliphatic linear or branched polyhydroxy alcohols with 3 to 6 hydroxyl groups, and, as chain stopping agents, aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acids or aliphatic linear or branched monobasic C.sub.1- to C.sub.30-alcohols, as an additive in a fuel for minimization of power loss in the operation of an internal combustion engine with this fuel.

Disclosed is a method of lubricating a gas engine using a lubricant including at least one mineral base oil and at least one ester selected from among the polyol esters. The composition includes at least 50% by weight of mineral base oil and at least 5% by weight of polyol ester relative to the total weight of the lubricant composition.

A manufacturing method of a lubricant composition includes mixing a composite ester A that contains polyester obtained by condensing trihydric or more polyhydric alcohol a1, a divalent or more polyvalent carboxylic acid a2, and at least one selected from monohydric alcohol a3 or a monovalent carboxylic acid a4, with a compound B having a hydroxyl number of greater than 50 mgKOH/g. A lubricant composition contains the composite ester A and the compound B.

A lubricant base oil composed of an ester. The ester includes a component (A) derived from trimethylolpropane in a molar percentage A.sub.mol% of 25 to 42 mol %; components (B) derived from monovalent straight-chain saturated fatty acids each having a carbon number of 8 to 12 in a molar percentage B.sub.mol% of 33 to 55 mol %: and a component (C) derived from adipic acid in a molar ratio C.sub.mol% of 12 to 34 mol %. The components (B) include lauric acid in a molar percentage of 5 to 50 mol %, and (B.sub.COOH+C.sub.COOH)/A.sub.OH is 0.90 to 1.02. A.sub.OH represents a hydroxyl equivalent of the component (A), B.sub.COOH represents a carboxyl group equivalent of the components (B); and C.sub.COOH represents a carboxyl group equivalent of the component (C).

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.

Levulinic-capped estolides having improved physical properties that make them more desirable and suitable as bio-based industrial or commercial products are disclosed. The physical properties of the disclosed estolide compositions have surprisingly low pour points that are substantially lower than previously known estolide compounds and superior to petroleum-based compounds designed for similar applications.

The invention refers to use of lubricant compositions comprising a specific diester and additives to reduce the fuel consumption of an engine.

The invention refers to lubricant compositions comprising a specific diester together with a viscosity index improver.

The use of a complex ester obtainable by esterification reaction between aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acids, aliphatic linear or branched polyhydroxy alcohols with 3 to 6 hydroxyl groups, and, as chain stopping agents, aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acids or aliphatic linear or branched monobasic C.sub.1- to C.sub.30-alcohols, as an additive in a fuel for minimization of power loss in the operation of an internal combustion engine with this fuel.

The present invention relates to a lubricating oil composition comprising polyglycerol partial esters of polyfunctional carboxylic acids and saturated or unsaturated, linear or branched fatty acids and/or poly(hydroxystearic acid) and the use thereof to lubricate an engine and reduce friction.