The present invention relates to the use of at least one, optionally alkylated diarylamine in a fuel or a fuel additive for cleaning the combustion chamber of an internal combustion engine, in particular of a motor vehicle engine. A further aspect relates to a method for cleaning the combustion chamber of an internal combustion engine during the operation of the internal combustion engine by burning a fuel, wherein the fuel contains a fuel additive comprising at least one, optionally alkylated diarylamine.

Disclosed herein are paraffin suppressant compositions, and methods of making and using them. The compositions comprise a paraffin inhibitor, a hydrocarbon-soluble hydrotrope equivalent, and optionally one or more additional paraffin dispersants. When added to hydrocarbon media such as crude oils to form crude oil compositions, the suppressant compositions inhibit the precipitation of paraffin waxes in the crude oil compositions. The suppressant compositions, added to hydrocarbon media such as hydrocarbon solvents or crude oils, exhibit reduced precipitation, gelling, and/or crystallization of paraffin inhibitor from the hydrocarbon media, when the media are subjected to sustained temperatures between 4 C. and 60 C.

The present invention describes alkoxylated amines as fuel additives for reducing injector deposits in direct injection gasoline engines.

A quaternary ammonium salt of formula (I): wherein X is a linking group; Y is O, NH or NR.sup.1 wherein R.sup.1 is H or an optionally substituted hydrocarbyl group; Q.sup.+ is a moiety that includes a quaternary ammonium cation; A.sup. is an anion; R.sup.2 is an optionally substituted alkylene group; R.sup.3 is hydrogen or an optionally substituted hydrocarbyl group; and n is 0 or a positive integer; provided that n is not 0 when R.sup.3 is hydrogen.

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Fuel additive compositions that include synergistic mixtures of one or more neutral lubricity additives and one or more monoacidic lubricity additives to provide wear and/or friction reduction in fuels.

Additive compositions comprising (a) a hydroxycarboxylic acid; and (b) a compound derived from a hydrocarbyl-substituted succinic acid or anhydride wherein the ratio of (a) to (b) in the additive composition ranges from 1:9 to 9:1. The additive compositions may be added to a fuel. Methods of reducing wear in an engine comprising operating the engine using a fuel composition have the additive composition therein. The use of an additive composition in a fuel composition to reduce the fuel composition's coefficient of friction or to reduce wear in an engine.

Method for reducing intake valve deposits in a spark ignition internal combustion engine which is fuelled with a gasoline fuel composition, wherein the method comprises introducing into the engine an aqueous based composition, wherein the aqueous based composition comprises (i) water, (ii) from 0 vol % to 40 vol % freezing point suppression agent, (iii) from 0 vol % to 10 vol % of surfactant, and (iv) an amine compound in a blending amount of from 0 ppmw to 1000 ppmw.

Method for reducing intake valve deposits in a spark ignition internal combustion engine which is fuelled with a gasoline fuel composition, wherein the method comprises introducing into the engine an aqueous based composition, wherein the aqueous based composition comprises (i) water, (ii) from 0 vol % to 40 vol % freezing point suppression agent, (iii) from 0 vol % to 10 vol % of surfactant, and (iv) an amine compound in a blending amount of from 0 ppmw to 1000 ppmw.

Fuel additive compositions having at least one acylated detergent, at least one Mannich detergent, and at least one polyether and/or polyetheramine. The acylated detergent may be the reaction product of a hydrocarbyl-substituted acylating agent and a nitrogen containing compound having at least one amino group, that may optionally be quaternizable, and at least one oxygen or nitrogen atom capable of reacting with the hydrocarbyl-substituted acylating agent. The compositions are useful for reducing the formation of carbonaceous deposits and/or cleaning carbonaceous deposits in an engine, such as a gasoline direct injection engine.

Fuel additive compositions having at least one acylated detergent, at least one Mannich detergent, and at least one polyether and/or polyetheramine. The acylated detergent may be the reaction product of a hydrocarbyl-substituted acylating agent and a nitrogen containing compound having at least one amino group, that may optionally be quaternizable, and at least one oxygen or nitrogen atom capable of reacting with the hydrocarbyl-substituted acylating agent. The compositions are useful for reducing the formation of carbonaceous deposits and/or cleaning carbonaceous deposits in an engine, such as a gasoline direct injection engine.