The use as a piston varnish controlling additive in a fuel composition for a spark-ignition internal combustion engine or a compression-ignition gasoline internal combustion engine of a combination of: a. a hydrocarbyl-substituted aromatic compound; and b. a polyalkylene amine. The fuel composition may also be used for controlling power output, fuel economy, engine wear, piston ring sticking and blow-by.

A quaternary ammonium compound of formula (I): ##STR00001##
wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R.sup.5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R.sup.5 is hydrogen.

A quaternary ammonium compound of formula (I): ##STR00001##
wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R.sup.5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R.sup.5 is hydrogen.

Described herein are associative polymers capable of controlling one or more physical and/or chemical properties of non-polar compositions and related compositions, methods and systems.

The invention relates to a fuel composition based on a diesel fraction, having a sulphur content of less than 10 mg/kg with the boiling range of 180-360° C., characterized in that said fuel composition contains organic peroxides as ignition promoters, which are selected from the group: di-tert-butyl peroxide, 1,1-di-(tert-butylperoxy)cyclohexane, dicumyl peroxide, tert-butyl cumyl peroxide, isobutyl cumyl peroxide, n-butyl cumyl peroxide, isopropyl cumyl peroxide, ethyl cumyl peroxide and methyl cumyl peroxide, and contains an anti-wear additive based on carboxylic acids having the following ratio of components, wt %: 0.01-0.5 organic peroxide, 0.005-0.1 anti-wear additive, and up to 100 being the diesel fraction. The proposed diesel fuel composition allows producing diesel fuel which meets quality performance requirements.

The invention relates to a fuel composition based on a diesel fraction, having a sulphur content of less than 10 mg/kg with the boiling range of 180-360° C., characterized in that said fuel composition contains organic peroxides as ignition promoters, which are selected from the group: di-tert-butyl peroxide, 1,1-di-(tert-butylperoxy)cyclohexane, dicumyl peroxide, tert-butyl cumyl peroxide, isobutyl cumyl peroxide, n-butyl cumyl peroxide, isopropyl cumyl peroxide, ethyl cumyl peroxide and methyl cumyl peroxide, and contains an anti-wear additive based on carboxylic acids having the following ratio of components, wt %: 0.01-0.5 organic peroxide, 0.005-0.1 anti-wear additive, and up to 100 being the diesel fraction. The proposed diesel fuel composition allows producing diesel fuel which meets quality performance requirements.

A fuel composition comprising a base fuel and at least one viscosity index (VI) improving additive, wherein the viscosity index (VI) improving additive is a star-shaped polyisoprene-based polymer. The viscosity index improving additive can be used in a fuel composition to provide improved lubricity as well as providing improved power output and/or acceleration characteristics.

A fuel composition comprising a base fuel and at least one viscosity index (VI) improving additive, wherein the viscosity index (VI) improving additive is a star-shaped polyisoprene-based polymer. The viscosity index improving additive can be used in a fuel composition to provide improved lubricity as well as providing improved power output and/or acceleration characteristics.

Lubricity additives for hydrocarbon fuels are provided according to formula I:

##STR00001##

wherein n is 1 or 0; each Q is independently selected from oxygen and sulfur; each R is independently selected from C8-C60 alkenyl groups which are substituted or unsubstituted; and L is a linking group comprising 0-20 carbons which may be substituted or unsubstituted and may optionally comprise catenary heteroatoms. Fuel mixtures comprising a hydrocarbon fuel; and a lubricity additive according to the present disclosure are also provided. Methods of making lubricity additives comprise reacting an alkenyl succinic anhydrides (ASA's) with certain bisamides or bisthioamides.

Lubricity additives for hydrocarbon fuels are provided according to formula I:

##STR00001##

wherein n is 1 or 0; each Q is independently selected from oxygen and sulfur; each R is independently selected from C8-C60 alkenyl groups which are substituted or unsubstituted; and L is a linking group comprising 0-20 carbons which may be substituted or unsubstituted and may optionally comprise catenary heteroatoms. Fuel mixtures comprising a hydrocarbon fuel; and a lubricity additive according to the present disclosure are also provided. Methods of making lubricity additives comprise reacting an alkenyl succinic anhydrides (ASA's) with certain bisamides or bisthioamides.