Abstract: A method of removing deposits in a direct injection spark ignition engine, the method including combusting in the engine a gasoline fuel composition having a quaternary ammonium salt additive wherein the quaternary ammonium salt additive includes the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; in which each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

Abstract: A diesel fuel composition including (a) a quaternary ammonium salt additive; and (b) one or more nitrogen-free detergents; wherein the quaternary ammonium salt additive includes the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; wherein each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

Abstract: A method of cleaning up internal diesel injector deposits in a severely fouled engine, the method including combusting in the engine a diesel fuel composition having (a) a quaternary ammonium salt additive; and (b) one or more further nitrogen-containing detergents; in which the quaternary ammonium salt additive includes the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; in which each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

Abstract: The use of a nitrogen containing detergent as an additive in a diesel fuel composition to reduce the impact of deposits in a post combustion system of a diesel engine when combusting said diesel fuel composition.

Abstract: A method of cleaning up deposits in an indirect injection diesel engine, the method including combusting in the engine a diesel fuel composition having a quaternary ammonium salt additive; and optionally one or more further nitrogen-containing detergents; wherein the quaternary ammonium salt additive comprises the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; wherein each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

Abstract: A quaternary ammonium compound of formula (X): wherein R0, R1, R2 and R3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.

Abstract: A method of reducing deposits in a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising a detergent additive which is not a quaternary ammonium salt or a Mannich reaction product; and a quaternary ammonium salt additive comprising the reaction product of nitrogen containing species having at least one tertiary amine group and a quaternizing agent; wherein the nitrogen containing species is selected from: (i) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; (ii) a Mannich reaction product comprising a tertiary amine group; and (v) a polyalkylene substituted amine having at least one tertiary amine group.

Abstract: A quaternary ammonium compound which is the reaction product of: (a) a tertiary amine having a molecular weight of less than 1000; (b) an acid-activated alkylating agent; and (c) a diacid including an optionally substituted hydrocarbyl moiety having at least (5) carbon atoms.

Abstract: A quaternary ammonium compound of formula (X): wherein R0, R1, R2 and R3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.

Abstract: A quaternary ammonium compound of formula (X), wherein R0, R, R2 and R3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.

Abstract: A quaternary ammonium salt of formula wherein each of R1, R2, R3 and R4 is independently selected from an optionally substituted alkyl, alkenyl or aryl group having less than 8 carbon atoms and R5 is hydrogen or an optionally substituted hydrocarbyl group.

Abstract: A diesel fuel composition comprising a first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; wherein the quaternary ammonium salt additive (i) is formed by the reaction a quaternising agent which is not an ester and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R2 and R3 are the same or different alkyl, alkenyl or aryl groups having from 1 to 22 carbon atoms; X is a bond or alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C22 alkyl group; and wherein the Mannich reaction product additive (ii) is the product of a Mannich reaction between: (d) an aldehyde; (e) an amine; and (f) a substituted phenol; wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of between 200 and 3000.

Abstract: A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) (i) formed by the reaction of a compound of formula (A): and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R2 and R3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C36 alkyl group.

Abstract: A diesel fuel composition comprising a first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; wherein the quaternary ammonium salt additive (i) is formed by the reaction of a compound of formula (A): R O O R1 10 (A) and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): 15 N X R3 R2 NHR4 N X R3 R2 [O(CH2)m]nOH (B1) (B2) wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R1 is a C1 to C22 alkyl, aryl or alkylaryl group; wherein R2 and R3 are the same or different alkyl, alkenyl or aryl groups having from 1 to 22 carbon atoms; X is a bond or alkylene group having from 1 to 20 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C22 alkyl group; and wherein the Mannich reaction product additive (ii) is the product of a Mannich reaction between: (d) an aldehyde; (e) an amine; and25 (f) a substituted phenol; wherein the phe

Abstract: A quaternary ammonium salt of formula wherein each of R1, R2, R3 and R4 is independently selected from an optionally substituted alkyl, alkenyl or aryl group having less than 8 carbon atoms and R5 is hydrogen or an optionally substituted hydrocarbyl group.

Abstract: A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) (i) formed by the reaction of a compound of formula (A): and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R2 and R3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C36 alkyl group.

Abstract: A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) (i) formed by the reaction of a compound of formula (A): and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R2 and R3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C36 alkyl group.

Abstract: A method of removing deposits from a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising an engine cleaning additive, wherein the engine cleaning additive is the product of a Mannich reaction between: (a) an aldehyde; (b) ammonia, hydrazine or an amine; and (c) an optionally substituted phenol; wherein the or each substituent of the phenol component (c) has an average molecular weight of less than 400.

Abstract: A diesel fuel composition comprising a quaternary ammonium salt additive which additive is formed by the reaction of (1) a quaternising agent and (2) a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and at least 1.4 molar equivalents of an amine of formula (B1) or (B2), wherein R2 and R3 are the same or different alkyl, alkenyl or aryl groups having from 1 to 22 carbon atoms; X is a bond or alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C22 alkyl group.

Abstract: A quaternary ammonium compound of formula (X), wherein R0, R, R2 and R3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.