Fuel composition

Abstract

Use of a deposit control additive composition in a diesel fuel composition, wherein the deposit control additive composition comprises an imide containing quaternary ammonium salt ('imide quat'), wherein the imide quat comprises the reaction product of: (a) a quaternizable compound that is the reaction product of: (i) a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent has a number average molecular weight ranging from 100 to 10000, and (ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl- substituted acylating agent to form an imide, and further having at least one quaternizable amino group; and (b) a quaternizing agent suitable for converting the quaternizable amino group of the nitrogen containing compound to a quaternary nitrogen, for reducing the measured regeneration frequency of a diesel particulate filter in a vehicle combusting the diesel fuel composition.

Description

[0001] SP3167

[0002] 1

[0003] FUEL COMPOSITION

[0004] Field of the Invention

[0005] The present invention relates to the use of a fuel composition for reducing the measured regeneration frequency of a diesel particulate filter in a vehicle combusting a diesel fuel composition. Background of the Invention

[0006] Diesel engines commonly result in combustion contaminants and particulates that tend to be undesired for a variety of reasons . The contaminants and particulates are often due to the incomplete combustion that tends to be inherent in the diesel engine and often results in small soot particles. A diesel particulate filter or DPF is a filtration device employed on modern vehicles combusting diesel fuel to remove the particulate and soot from the exhaust gas stream of the diesel engine.

[0007] During normal use, the DPF accumulates soot and particulate on or in the filter media. The filter can either be replaced or, more commonly, regenerated to burn off the accumulated soot. Regeneration is often achieved by increasing exhaust gas temperatures either through passive or active means in conjunction with injecting excess fuel into the cylinders. Such extra injections of fuel can lead to reductions in fuel economy. It would therefore be desirable to find ways of reducing the regeneration frequency of the diesel particulate filter.

[0008] US11, 685,871 B2 relates to a method for reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel and to the use of one or more diesel performance additives to reduce measured regeneration frequency and improve fuel economy. SP3167

[0009] 2

[0010] US2017 / 0114296 relates to imide containing quaternary ammonium salts having a hydrocarbyl substituent of number average molecular weight ranging from 300 to 750, and the use of such quaternary ammonium salts in fuel compositions to improve the water shedding performance of the fuel composition .

[0011] US2018 / 0355267 relates to ultra-low molecular weight imide containing quaternary ammonium salts having short hydrocarbon tails of average molecular weight of less than 300, and the use of such quaternary ammonium salts to improve additive package stability. Summary of the Invention

[0012] According to the present invention there is provided the use of a deposit control additive composition in a diesel fuel composition, wherein the deposit control additive composition comprises an imide containing quaternary ammonium salt ( 'imide quat' ) , wherein the imide quat comprises the reaction product of:

[0013] (a) a quaternizable compound that is the reaction product of :

[0014] (i) a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent has a number average molecular weight ranging from 100 to 10000, and

[0015] (ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl- substituted acylating agent to form an imide, and further having at least one quaternizable amino group; and

[0016] (b) a quaternizing agent suitable for converting the quaternizable amino group of the nitrogen containing compound to a quaternary nitrogen, SP3167

[0017] 3 for reducing the measured regeneration frequency of a diesel particulate filter in a vehicle combusting the diesel fuel composition .

[0018] According to the present invention, there is further provided a method for reducing the measured regeneration frequency of a diesel particulate filter in a diesel vehicle which comprises a compression ignition internal combustion engine and a diesel particulate filter wherein the method comprises :

[0019] (A) fuelling the compression ignition internal combustion engine with a diesel fuel composition comprising a diesel base fuel and a deposit control additive composition, wherein the deposit control additive composition comprises an imide containing quaternary ammonium salt ( 'imide quat' ) , wherein the imide quat comprises the reaction product of:

[0020] (a) a quaternizable compound that is the reaction product of :

[0021] (i) a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent has a number average molecular weight ranging from 100 to 10000, and

[0022] (ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl- substituted acylating agent to form an imide, and further having at least one quaternizable amino group; and

[0023] (b) a quaternizing agent suitable for converting the quaternizable amino group of the nitrogen containing compound to a quaternary nitrogen;

[0024] (B) combusting the diesel fuel composition in the compression ignition internal combustion engine;

[0025] (C) regenerating the diesel particulate filter while combusting the diesel fuel composition; and SP3167

[0026] 4

[0027] (D) comparing the frequency of regeneration of the diesel particulate filter when combusting the diesel fuel composition with the frequency of regeneration of the diesel particulate filter when combusting an analogous diesel fuel composition which does not comprise the deposit control additive composition, wherein the frequency of regeneration per 1000 miles of the diesel particulate filter when combusting the diesel fuel composition comprising the deposit control additive composition is lower than a frequency of regeneration per 1000 miles of the diesel particulate filter when combusting an analogous diesel fuel composition which does not comprise the deposit control additive composition.

[0028] It has surprisingly been found that the diesel fuel composition comprising said imide quat provides reduced DPF regeneration frequency. Detailed Description of the Invention

[0029] The present invention relates to the use of a deposit control additive composition in a diesel fuel composition comprising imide containing quaternary ammonium salts (referred to herein as 'imide quat' ) having a hydrocarbyl substituent of number average molecular weight of 100 to 10000 for reducing the frequency of diesel particulate filter regeneration.

[0030] DPF regeneration is the process of reducing the accumulated soot content in the diesel particulate filter, where soot content has been created during combustion and captured by the DPF. It involves burning off the accumulated excess soot and other particles to allow for the DPF to continue to control the particulate emissions from diesel engines .

[0031] As used herein, the term "reducing the frequency of diesel particulate filter (DPF) regeneration" refers to decreasing the number of regeneration events triggered, SP3167

[0032] 5 either actively or passively, by the vehicle over a given mileage, total fuel consumption, or through the lifetime of the DPF.

[0033] The frequency of DPF regeneration can be measured using any suitable method known to those skilled in the art. For example, this can be done by operating a vehicle equipped with a DPF either with an existing or custom transient cycle, or at a stable load point with constant speed, such cycle can be designed to include a specific number of DPF regeneration events, measuring the distance required to trigger each regeneration event to compare the influence of different fuels on the DPF regeneration cycle.

[0034] During this cycle, soot formation at the engine outlet could be monitored, regeneration events in the DPF could be measured by using a pressure differential probe or by tracking the temperature within the DPF. The regeneration events could be monitored by observing the pressure build-up in the DPF until a maximum pressure is reached, at which point the vehicle actively triggers a DPF regeneration event to remove the soot and reduce the pressure build-up.

[0035] In parallel, temperature and fuel consumption could be monitored. The active regeneration event requires extra fuel to be injected after the combustion in the combustion chamber to ensure the fuel burns the soot captured in the DPF. This process increases the temperature during regeneration events, which then returns to a baseline condition once the regeneration event is completed. By knowing when a Regeneration Event starts and finishes, the distance required from the last regeneration event to the new regeneration event can be measured which ultimately is the important factor to differentiate between different fuels.

[0036] The reduction in the frequency of DPF regeneration can encompass any degree of reduction, for example, a reduction SP3167

[0037] 6 of at least 10%, or at least 20%, or at least 30%, or at least 50%, or at least 60%, compared to the frequency of DPF regeneration experienced by an analogous diesel fuel composition not containing the deposit control additive composition described herein.

[0038] The diesel fuel composition used in the present invention comprises a diesel base fuel and a deposit control additive composition. The deposit control additive composition comprises an imide containing quaternary ammonium salt ( 'imide quat' ) . As used herein, the phrase 'deposit control additive' refers to the 'imide quat' itself. The deposit control additive composition is a composition which comprises the deposit control additive (the 'imide quat' ) . The imide quat comprises the reaction product of (a) a quaternizable compound and (b) a quaternizing agent. The quaternizable compound is a reaction product of (i) a hydrocarbyl-substituted acylating agent having a number average molecular weight ranging from 100 to 10000, and (ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl-substituted acylating agent to form an imide, and further having at least one quaternizable amino group. The quaternizing agent is a compound which is suitable for converting the quaternizable amino group of the nitrogen-containing compound to a quaternary nitrogen.

[0039] The number average molecular weight of the materials described herein is measured using gas permeation chromatography (GPC) using a Waters GPC 2000 equipped with a refractive index detector and Waters Empower (RTM) data acquisition and analysis software. The columns are polystyrene (PL gel, 5 micron, available from Agilent / Polymer Laboratories, Inc. ) . For the mobile phase, individual samples are dissolved in THF and filtered with PTFE filters SP3167

[0040] 7 before they are injected into the GPC port. The Waters GPC 2000 Operating Conditions are as follows:

[0041] Injector, Column and Pump / Solvent compartment temperatures: 40°C.

[0042] Autosampler Control: Run time: 40 minutes

[0043] Injection volume: 300 microliter

[0044] Pump: System pressure: approx.. 90 bars (Max. pressure limit: 270 bars, Min. pressure limit: 0 psi)

[0045] Flow rate: 1.0 ml / minute

[0046] Differential Refractometer (RI) : Sensitivity: -16; Scale factor: 6 Production of imide quat

[0047] The imide quat is produced according to the method provided in US2017 / 0114296A1 , incorporated herein by reference in its entirety. US2017 / 0114296A1 discloses the production of imide quats wherein the hydrocarbyl substituent of the hydrocarbyl-substituted acylating agent used in the production process, and described above, has a number average molecular weight ranging from 100 to 10000. Imide quats wherein the hydrocarbyl substituent of the hydrocarbyl- substituted acylating agent used in the production process has a number average molecular weight of less than 300 or a number average molecular weight of greater than 750, can also be produced by the methods provided in US2018 / 0355267 , incorporated herein by reference in its entirety.

[0048] The term 'imide quat' as used herein can be used interchangeably with the term 'Deposit Control Additive' . In one embodiment, the imide quat used herein may be described as the reaction product of (a) a quaternizable compound, and (b) a quaternizing agent. As used herein, reference to imide quat (s) includes reference to the mixture of compounds having a number average molecular weight ranging from 100 to 10000, including a quaternary ammonium salt or SP3167

[0049] 8 salts as described herein, as well as referring to the quaternary ammonium salt itself.

[0050] The quaternizable compound of (a) used to prepare the imide quat itself may be the reaction product of (i) a hydrocarbyl-substituted acylating agent, and (ii) a nitrogencontaining compound. More particularly, the hydrocarbyl- substituted acylating agent is functionalized with a hydrocarbyl substituent having a number average molecular weight in the range from 100 to 10000, more preferably in the range from 225 to 1000, most preferably in the range from 300 to 750.

[0051] The hydrocarbyl-substituted acylating agent employed to prepare the quaternizable compound can be the reaction product of the precursor to the hydrocarbyl substituent, which isa long chain hydrocarbon, generally a polyolefin, with a monounsaturated carboxylic acid reactant such as (i) a, p-monounsaturated C4 to C19 dicarboxylic acid such as fumaric acid, itaconic acid, maleic acid; (ii) derivatives of (i) such as anhydrides or Ci to C5 alcohol derived mono- or di-esters of (i) .

[0052] The hydrocarbyl substituent is a long chain hydrocarbyl group having a number average molecular weight in the range from 100 to 10000. In one embodiment, the hydrocarbyl group has a number average molecular weight (Mn) of 225 to 1000. In a preferred embodiment, the hydrocarbyl group has a number average molecular weight in the range from 300 to 750. The Mn of the hydrocarbyl substituent can also be from 350 to 700, and in some cases from 400 to 600, or 650. In yet another embodiment, the hydrocarbyl substituent may have a number average molecular weight of 550. In an embodiment, the hydrocarbyl substituent can be any compound containing an olefinic bond represented by the general formula (I) :

[0053] (R1(R2) C=C (R6) (CH (R7) (R8) ) (I) SP3167

[0054] 9 wherein each of R1and R2is, independently, H or a hydrocarbon based group. Each of R6, R7and R8is, independently, H or a hydrocarbon based group; preferably at least one is a hydrocarbon based group containing at least 20 carbon atoms.

[0055] Olefin polymers for reaction with the monounsaturated carboxylic acids can include polymers comprising a major molar amount of C2 to C20, e.g. C2 to C5 monoolefin. Such olefins include ethylene, propylene, butylene, isobutylene, pentene, octene-1, or styrene. The polymers can be homopolymers such as polyisobutylene as well as copolymers of two or more of such olefins such as copolymers of : ethylene and propylene; butylene and isobutylene; propylene and isobutylene. Other copolymers include those in which a minor molar amount of the copolymer monomers e.g. 1 to 10 mole% is a C4 to Cis diolefin, e.g. a copolymer of isobutylene and butadiene; or a copolymer of ethylene, propylene and 1,4- hexadiene .

[0056] In one embodiment, at least one R of formula (I) is derived from polybutene, that is, polymers of C4 olefins, including 1-butene, 2-butene and isobutylene. C4 polymers can include polyisobutylene. In another embodiment, at least one R of formula (I) is derived from ethylene-alpha olefin polymers, including ethylene-propylene-diene polymers. Ethylene-alpha olefin copolymers and ethylene-lower olefindiene terpolymers are described in numerous patent documents, including European patent publication EP 0 279 863 and the following U.S. Pat. Nos. 3,598,738; 4, 026,809; 4, 032,700; 4,137,185; 4, 156,061; 4,320,019; 4,357,250; 4, 658,078; 4,668,834; 4, 937,299; 5,324,800 each of which are incorporated herein by reference for relevant disclosures of these ethylene based polymers. SP3167

[0057] - 10 -

[0058] In another embodiment, the olefinic bonds of formula (I) are predominantly vinylidene groups, represented by the following formulas:

[0059] (ID wherein R is a hydrocarbyl group

[0060] (III) wherein R is a hydrocarbyl group.

[0061] In one embodiment, the vinylidene content of formula (I) can comprise at least 30 mole % vinylidene groups, at least 50 mole % vinylidene groups, or at least 70 mole % vinylidene groups . Such material and methods for preparing them are described in U.S. Pat. Nos. 5,071, 919; 5,137, 978; 5,137,980; 5,286,823, 5,408,018, 6,562, 913, 6, 683,138, 7,037, 999 and U.S. Publication Nos. 20040176552A1 , 20050137363 and 20060079652A1, which are expressly incorporated herein by reference, such products are commercially available by BASF, under the trade name GLISSOPAL® and by Texas PetroChemical LP, under the trade name TPC 1105™ and TPC 595™.

[0062] In other embodiments, the hydrocarbyl-substituted acylating agent may be a "conventional" vinylidene SP3167

[0063] - 11 - polyisobutylene (PIB) wherein less than 20% of the head groups are vinylidene head groups as measured by nuclear magnetic resonance (NMR) . Alternatively, the hydrocarbyl- substituted acylating agent may be a mid-vinylidene PIB or a high-vinylidene PIB. In mid-vinylidene PIBs, the percentage of head groups that are vinylidene groups can range from greater than 20% to 70%. In high-vinylidene PIBs, the percentage of head groups that are vinylidene head groups is greater than 70%.

[0064] Methods of making hydrocarbyl substituted acylating agents from the reaction of the monounsaturated carboxylic acid reactant and the compound of formula (I) are well known in the art and disclosed in the following patents: U.S. Pat. Nos. 3,361, 673 and 3, 401, 118 to cause a thermal "ene" reaction to take place; U.S. Pat. Nos. 3,087, 436; 3,172,892; 3,272,746, 3,215,707; 3,231,587; 3, 912,764; 4,110,349; 4,234,435; 6,077, 909; 6,165,235 and are hereby incorporated by reference. Nitrogen Containing Compound

[0065] The composition of the present invention contains a nitrogen containing compound having a nitrogen atom capable of reacting with the acylating agent and further having a quaternizable amino group. A quaternizable amino group is any primary, secondary or tertiary amino group on the nitrogen containing compound that is available to react with a quaternizing agent to become a quaternary amino group.

[0066] In one embodiment, the nitrogen containing compound can be represented by the following formulas: SP3167

[0067] - 12 - wherein X is an alkylene group containing 1 to 4 carbon atoms; R2is hydrogen or a hydrocarbyl group; and R3and R4are hydrocarbyl groups.

[0068] Examples of the nitrogen containing compound capable of reacting with the acylating agent can include but is not limited to: dimethylaminopropylamine, N, N-dimethyl- aminopropylamine , N, N-diethyl-aminopropylamine , N, N-dimethyl- aminoethylamine ethylenediamine, 1, 2-propylenediamine, 1,3- propylene diamine, isomeric amines, including butylenediamines, pentanediamines, hexanediamines, and heptanediamines, diethylenetriamine, dipropylenetriamine, dibutylene triamine , triethylene tetramine , tetraethylenepentamine , pentaethylenehexamine , hexamethylenetetramine, and bis (hexamethylene ) triamine, the diaminobenzenes, the diaminopyridines, N-methyl-3-amino-l- propylamine, or mixtures thereof. The nitrogen containing compounds capable of reacting with the acylating agent and further having a quaternizable amino group can further include aminoalkyl substituted heterocyclic compounds such as 1- (3-aminopropyl) imidazole and 4- (3-aminopropyl) morpholine, 1- (2-aminoethyl) piperidine, 3, 3-diamino-N- methyldipropylamine . In some embodiments, dimethylaminopropylamine is the preferred nitrogen containing compound. In some embodiments, the nitrogen containing compound excludes dimethylaminopropylamine.

[0069] In one embodiment, the nitrogen containing compound can be an imidazole, for example, as represented by the following formula : imidazole SP3167

[0070] - 13 -

[0071] (IX) wherein R is an amine capable of condensing with said hydrocarbyl-substituted acylating agent and having from 3 to 8 carbon atoms .

[0072] In one embodiment, the nitrogen containing compound can be represented by formula X: wherein each X can be, individually, a Ci to Ce hydrocarbylene group, and each R can be, individually, a hydrogen or a Ci to Ce hydrocarbyl group. In one embodiment, X can be, for example, a Ci, C2 or C3 alkylene group. In the same or different embodiments, each R can be, for example, H or a Ci, C2 or C3 alkyl group.

[0073] Quaternizable Compound

[0074] The hydrocarbyl substituted acylating agents and nitrogen containing compounds described above are reacted together to form a quaternizable compound. Methods and process for reacting the hydrocarbyl substituted acylating agents and nitrogen containing compounds are well known in the art.

[0075] In embodiments, the reaction between the hydrocarbyl substituted acylating agents and nitrogen containing compounds can be carried out at temperatures of greater than SP3167

[0076] 14

[0077] 80° C. , or 90° C. , or in some cases 100° C. , such as between 100 and 150 or 200° C. , or 125 and 175° C. At the foregoing temperatures water may be produced during the condensation, which is referred to herein as the water of reaction. In some embodiments, the water of reaction can be removed during the reaction, such that the water of reaction does not return to the reaction and further react.

[0078] The hydrocarbyl substituted acylating agents and nitrogen containing compounds may be reacted at a ratio of 1:1, but the reaction may also containing the respective reactants (i.e. , hydrocarbyl substituted acylating agent : nitrogen containing compound) from 3:1 to 1:1.2, or from 2.5:1 to 1:1.1, and in some embodiments from 2:1 to 1:1.05.

[0079] Quaternizing Agent

[0080] The quaternary ammonium salt can be formed when the quaternizable compound, that is, the reaction products of the hydrocarbyl substituted acylating agent and nitrogen containing compounds described above, are reacted with a quaternizing agent. Suitable quaternizing agents can include, for example, dialkyl sulfates, alkyl halides, hydrocarbyl substituted carbonates; hydrocarbyl epoxides, carboxylates, alkyl esters, and mixtures thereof.

[0081] In one embodiment, the quaternizing agent can include alkyl halides, such as chlorides, iodides or bromides; alkyl sulfonates; dialkyl sulfates, such as, dimethyl sulfate and diethyl sulfate; sulfones; alkyl phosphates; such as, Cl-12 trialkylphosphates; di Cl-12 alkylphosphates; borates; Cl-12 alkyl borates; alkyl nitrites; alkyl nitrates; dialkyl carbonates, such as dimethyl oxalate; alkyl alkanoates, such as methylsalicylate; O,O-di-Cl-12 alkyldithiophosphates; or mixtures thereof. SP3167

[0082] - 15 -

[0083] In one embodiment, the quaternizing agent may be derived from dialkyl sulfates such as dimethyl sulfate or diethyl sulfate, N-oxides, sulfones such as propane and butane sulfone; alkyl, acyl or aryl halides such as methyl and ethyl chloride, bromide or iodide or benzyl chloride, and a hydrocarbyl (or alkyl) substituted carbonates. If the alkyl halide is benzyl chloride, the aromatic ring is optionally further substituted with alkyl or alkenyl groups.

[0084] The hydrocarbyl (or alkyl) groups of the hydrocarbyl substituted carbonates may contain 1 to 50, 1 to 20, 1 to 10 or 1 to 5 carbon atoms per group. In one embodiment, the hydrocarbyl substituted carbonates contain two hydrocarbyl groups that may be the same or different. Examples of suitable hydrocarbyl substituted carbonates include dimethyl or diethyl carbonate.

[0085] In another embodiment, the quaternizing agent can be a hydrocarbyl epoxide, for example, as represented by the following formula: wherein R1, R2,R3and R4can be independently H or a hydrocarbyl group contain from 1 to 50 carbon atoms. Examples of hydrocarbyl epoxides include: ethylene oxide, propylene oxide, butylene oxide, styrene oxide and combinations thereof. In one embodiment the quaternizing agent does not contain any styrene oxide .

[0086] In some embodiments, the hydrocarbyl epoxide can be an alcohol functionalized epoxide, C4 to C14 epoxides, and mixtures thereof. Exemplary C4 to C14 epoxides are those of formula XII where R1, R2, R3and R4can be independently H or a C2to C 12 hydroca rby 1 group. In an embodimentrthe epoxides can be C4 to C14 epoxides. Epoxides suitable as quaternizing agents in the present technology can include, for example, C4 to C14 epoxides having linear hydrocarbyl substituents, such as, for example, 2 -ethyloxirane , 2-propyloxirane, and the like, and C4 to C14 epoxides having branched and cyclic or aromatic substituents, such as, for example, styrene oxide. C4 to C14 epoxides can also include epoxidized triglycerides, fats or oils; epoxidized alkyl esters of fatty acids; and mixtures thereof. In yet another embodiment, the hydrocarbyl epoxide may be a C4-C20 epoxide.

[0087] Exemplary alcohol functionalized epoxides can include those of formula XII where R1, R2, R3and R4can be independently H or a hydroxyl containing hydrocarbyl group. In an embodiment, hydroxyl containing hydrocarbyl group can contain from 2 to 32, or from 3 to 28, or even from 3 to 24 carbon atoms. Exemplary alcohol functionalized epoxide derivatives can include for example, glycidol and the like. In some embodiments the hydrocarbyl epoxide can be employed in combination with an acid. The acid used with the hydrocarbyl epoxide may be a separate component, such as acetic acid. In other embodiments, a small amount of an acid component may be present, but at <0.2 or even <0.1 moles of acid per mole of hydrocarbyl acylating agent. These acids may also be used with the other quaternizing agents described above, including the hydrocarbyl substituted carbonates and related materials described below.

[0088] In some embodiments the quaternizing agent does not contain any substituent group that contains more than 20 carbon atoms.

[0089] In another embodiment the quaternizing agent can be an ester of a carboxylic acid capable of reacting with a tertiary amine to form a quaternary ammonium salt, or an 17 ester of a polycarboxylic acid. In a general sense such materials may be described as compounds having the structure:

[0090] Ris-C (=0)-OR2° (XIII) where R19is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group and R20is a hydrocarbyl group containing from 1 to 22 carbon atoms.

[0091] Suitable compounds include esters of carboxylic acids having a pKa of 3.5 or less. In some embodiments the compound is an ester of a carboxylic acid selected from a substituted aromatic carboxylic acid, an a-hydroxycarboxylic acid and a polycarboxylic acid. In some embodiments the compound is an ester of a substituted aromatic carboxylic acid and thus R19is a substituted aryl group. R19may be a substituted aryl group having 6 to 10 carbon atoms, a phenyl group, or a naphthyl group. R19may be suitably substituted with one or more groups selected from carboalkoxy, nitro, cyano, hydroxy, SR' or NR'R" where each of R' and R" may independently be hydrogen, or an optionally substituted alkyl, alkenyl, aryl or carboalkoxy groups. In some embodiments R' and R" are each independently hydrogen or an optionally substituted alkyl group containing from 1 to 22, 1 to 16, 1 to 10, or even 1 to 4 carbon atoms .

[0092] In some embodiments R19in the formula above is an aryl group substituted with one or more groups selected from hydroxyl, carboalkoxy, nitro, cyano and NH2. R19may be a poly-substituted aryl group, for example trihydroxyphenyl, but may also be a mono-substituted aryl group, for example an ortho substituted aryl group. R19may be substituted with a group selected from OH, NH2, NO2, or COOMe . Suitably R19is a hydroxy substituted aryl group. In some embodiments R19is a 2 -hydroxyphenyl group. R20may be an alkyl or alkylaryl SP3167

[0093] 18 group, for example an alkyl or alkylaryl group containing from 1 to 16 carbon atoms, or from 1 to 10, or 1 to 8 carbon atoms. R20may be methyl, ethyl, propyl, butyl, pentyl, benzyl or an isomer thereof. In some embodiments R20is benzyl or methyl. In some embodiments the quaternizing agent is methyl salicylate. In some embodiments the quaternizing agent excludes methyl salicylate.

[0094] In some embodiments the quaternizing agent is an ester of an alpha-hydroxycarboxylic acid. Compounds of this type suitable for use herein are described in EP 1254889. Examples of suitable compounds which contain the residue of an alphahydroxycarboxylic acid include (i) methyl-, ethyl-, propyl-, butyl-, pentyl-, hexyl-, benzyl-, phenyl-, and allyl esters of 2-hydroxyisobutyric acid; (ii) methyl-, ethyl-, propyl-, butyl-, pentyl-, hexyl-, benzyl-, phenyl-, and allyl esters of 2-hydroxy-2-methylbutyric acid; (iii) methyl-, ethyl-, propyl-, butyl-, pentyl-, hexyl-, benzyl-, phenyl-, and allyl esters of 2 -hydroxy-2 -ethylbutyric acid; (iv) methyl-, ethyl- , propyl-, butyl-, pentyl-, hexyl-, benzyl-, phenyl-, and allyl esters of lactic acid; and (v) methyl-, ethyl-, propyl- , butyl-, pentyl-, hexyl-, allyl-, benzyl-, and phenyl esters of glycolic acid. In some embodiments the quaternizing agent comprises methyl 2 -hydroxyisobutyrate .

[0095] In some embodiments the quaternizing agent comprises an ester of a polycarboxylic acid. In this definition we mean to include dicarboxylic acids and carboxylic acids having more than 2 acidic moieties. In some embodiments the esters are alkyl esters with alkyl groups that contain from 1 to 4 carbon atoms. Suitable examples include diesters of oxalic acid, diesters of phthalic acid, diesters of maleic acid, diesters of malonic acid or diesters or triesters of citric acid . SP3167

[0096] 19

[0097] In some embodiments the quaternizing agent is an ester of a carboxylic acid having a pKa of less than 3.5. In such embodiments in which the compound includes more than one acid group, we mean to refer to the first dissociation constant. The quaternizing agent may be selected from an ester of a carboxylic acid selected from one or more of oxalic acid, phthalic acid, salicylic acid, maleic acid, malonic acid, citric acid, nitrobenzoic acid, aminobenzoic acid and 2, 4, 6-trihydroxybenzoic acid. In some embodiments the quaternizing agent includes dimethyl oxalate, a terephthalate, such as dimethyl terephthalate, and methyl 2- nitrobenzoate .

[0098] Quaternizing agents capable of coupling more than one quaternizable compound also may be employed. By "coupling" more than one quaternizable compounds, it is meant that at least two quaternizable compounds react with the same quaternizing agent to form a compound of the at least two quaternizable compounds linked by the quaternizing agent. Such quaternizing agents may, in some instances, also be referred to as coupling quaternizing agents herein and can include, for example, polyepoxides, such as, for example, di- , tri-, or higher epoxides; polyhalides; epoxy-halides, aromatic polyesters, and mixtures thereof.

[0099] In one embodiment, the quaternizing agent can be a polyepoxide. Polyepoxides can include, for example, poly- glycidyls which can include, for example, di-epoxyoctane ; ethylene glycol diglycidyl ether; neopentyl glycol digycidyl ether; 1 , 4-butanediol diglycidyl ether; 3 (bis (glycidyl oxymethyl) -methoxy) -1, 2 -propanediol; 1, 4-cyclohexane dimethanol digylicidyl ether; diepoxycyclo-octane, bisphenol A diglycidyl ether 4-vinyl-l-cyclohexene diepoxide; N,N- Diglycidyl-4-4glycidyloxyaniline; 1, 6-hexane diglycidyl ether; trimethylolpropanetriglycidyl ether; SP3167

[0100] 20 polypropyleneglycol diglycidyl ether; polyepoxidized triglycerides, fats or oils; and mixtures thereof.

[0101] In one embodiment, the quaternizing agent may be derived from polyhalides, such as, for example, chlorides, iodides or bromides. Such polyhalides can include, but not be limited to, 1 , 5-dibromopentane ; 1 , 4-diiodobutane; 1,5- dichloropentane ; 1 , 12 -dichlorododecane ; 1 , 12-dibromododecane; 1 , 2 -diiodoethane ; 1 , 2 -dibromoethane ; and mixtures thereof.

[0102] In an embodiment, the quaternizing agent can be an epoxy-halide, such as, for example, epichlorohydrin and the like .

[0103] The quaternizing agent may also be a poly aromatic ester. Examples of poly aromatic esters can include, but not be limited to, 4 , 4 ' -oxybis (methylbenzoate ) ; dimethylterephthalate; and mixtures thereof.

[0104] In certain embodiments the molar ratio of the quaternizable compound to quaternizing agent is 1:0.1 to 2, or 1:1 to 1.5, or 1:1 to 1.3. In some embodiments, particularly when employing a coupling quaternizing agent, the ratio of the quaternizable compound to the quaternizing agent can be from 2:1 to 1:1.

[0105] Any of the quaternizing agents described above, including the hydrocarbyl epoxides, may be used in combination with an acid. Suitable acids include carboxylic acids, such as acetic acid, propionic acid, 2 -ethylhexanoic acid, and the like.

[0106] In some embodiments, the quaternizing agent can be employed in the presence of a protic solvent, such as, for example, 2-ethylhexanol, water, and combinations thereof. In some embodiments, the quaternizing agent can be employed in the presence of an acid. In yet another embodiment, the quaternizing agent can be employed in the presence of an acid and a protic solvent. In some embodiments, the acid can be an SP3167

[0107] 21 acid component in addition to the acid group present in the structure of the acylating agent. In further embodiments the reaction can be free of, or essentially free of, any additional acid component other than the acid group present in the structure of the acylating agent. By "free of" it is meant completely free, and by "essentially free" it is meant an amount that not materially affect the essential or basic and novel characteristics of the composition, such as, for example, less than 1% by weight.

[0108] While the process to prepare the quaternary ammonium salts can produce a mixture that is not readily definable apart from the process steps above, certain structural components may be expected in some circumstances. Further details of these structural components can be found in US2017 / 0114296 incorporated herein by reference.

[0109] Deposit Control Additive Composition

[0110] The deposit control additive composition comprises from 5 to 30 ppmw of imide quat, based on the weight of the total deposit control additive composition. In one embodiment, the deposit control additive composition comprises from 5 to 20 ppmw of imide quat. In another embodiment, the deposit control additive composition comprises from 10 to 30 ppmw of imide quat.

[0111] The deposit control additive composition can comprise one or more further additives suitable for use in a performance additive package, in addition to the imide quat. Such further additives can be included in the deposit control additive composition depending on the results desired and the application in which the deposit control additive composition will be used. US2018 / 0355267 , incorporated by reference herein, provides examples of further additives suitable for use in the deposit control additive composition in addition to the imide quat. Examples of suitable further additives SP3167

[0112] 22 include detergents, dispersants, demulsifiers, lubricity agents, cold flow improvers, antioxidants, foan inhibitors, metal deactivators, valve seat recession additives, biocides, antistatic agents, deicers, fluidizers, corrosion inhibitors, seal swelling agents, combustion improvers, wax control polymers, gas hydrate inhibitors, and mixtures thereof. One or more solvents may also be included in the deposit control additive composition in order to stabilise the composition, for example, Aromatic 150 solvent and ethyl hexyl alcohol.

[0113] In one embodiment herein, the deposit control additive composition comprises an imide quat and at least one other additive selected from a detergent, a dispersant, a demulsifier, a lubricity agent, a cold flow improver, an antioxidant, or a mixture thereof.

[0114] In a preferred embodiment, the deposit control additive composition comprises an amide quat and at least one other additive selected from hydrolysed succinic acids or anhydrides, foam inhibitors, and demulsifiers.

[0115] The hydrolyzed succinic acid or anhydride may have a molecular weight, M, ranging from 225 to 1000. In another embodiment, the hydrolyzed succinic acid or anhydride may have a molecular weight, M, of 1000 and comprise more than 70 mole % vinylidene groups ("high vinylidene") . In another embodiment, the hydrolyzed succinic acid or anhydride may have a M, of 550 and may comprise between 20 mole % and 70 mole % vinylidene groups ("mid vinylidene") . In yet other embodiments the hydrolyzed succinic acid or anhydride may have a M, of less than 550 and less than 20 mole % vinylidene groups ("conventional vinylidene") .

[0116] Foam inhibitors for use herein include those that may be useful in fuel and / or lubricant compositions including polysiloxanes, copolymers of ethyl acrylate and 2- SP3167

[0117] 23 ethylhexylacrylate and optionally vinyl acetate, fluorinated polysiloxanes, trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers. The deposit control additive composition may also a silicone-containing antifoam agent in combination with a C5-C17 alcohol.

[0118] Suitable demulsifiers for use in the deposit control additive composition include, but are not limited to, arylsulfonates and polyalkoxylated alcohol, such as, for example, polyethylene and polypropylene oxide copolymers and the like. Other suitable demulsifiers include nitrogen containing compounds such as oxazoline and imidazoline compounds and fatty amines, as well as Mannich compounds. Mannich compounds are the reaction products of alkylphenols and aldehydes (especially formaldehyde) and amines (especially amine condensates and polyalkylenepolyamines) . The materials described in the following U.S. patents are illustrative: U.S. Pat. Nos. 3, 036,003; 3,236,770; US 2018 / 0355267 Al, 3,414,347; 3,448,047; 3,461,172; 3,539, 633; 3,586, 629; 3,591,598; 3, 634,515; 3,725,480; 3,726,882; and 3, 980,569, herein incorporated by reference. Other suitable demulsifiers are, for example, the alkali metal or alkaline earth metal salts of alkylsubstituted phenol- and naphthalenesulfonates and the alkali metal or alkaline earth metal salts of fatty acids, and also neutral compounds such as alcohol alkoxylates, e.g. alcohol ethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylate or tert-pentylphenol ethoxylate, fatty acids, alkylphenols, condensation products of ethylene oxide (EO) and propylene oxide (P0) , for example including in the form of EO / PO block copolymers, polyethyleneimines or else polysiloxanes. Any of the commercially available demulsifiers may be employed, suitably SP3167

[0119] 24 in an amount sufficient to provide a treat level of from 5 to 50 ppm, more preferably from 5 to 25 ppm, and even more preferably from 5 to 20 ppm in the fuel, by total weight of the fuel. In one embodiment the fuel composition of the invention does not comprise a demulsifier. The demulsifiers may be used alone or in combination. Some demulsifiers are commercially available, for example from Nalco or Baker Hughes. Alternatively, demulsifiers comprising a hydrocarbyl- substituted dicarboxylic acid in the form of the free acid, or in the form of the anhydride which may be an intramolecular anhydride, such as succinic, glutaric, or phthalic anhydride, or an intermolecular anhydride linking two dicarboxylic acid molecules together. The hydrocarbyl substituent may have from 12 to 2000 carbon atoms and may include polyisobutenyl substituents having a number average molecular weight of 300 to 2800. Exemplary hydrocarbyl- substituted dicarboxylic acids include, but are not limited to, hydrocarbyl-substituted acids derived from malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, undecanedioic, dodecanedioic, phthalic, isophthalic, terphthalic, o- , m-, or p-phenylenediacetic, maleic, fumaric, or glutaconic acids.

[0120] In particular, Table 1 of US2018 / 0355267 provides specific examples of additive package compositions which comprise further additives suitable for use in a deposit control additive composition in addition to the imide quat (the latter is referred to as an Amide / Ester Quat in US2018 / 0355267 ) , e.g. Additive Package A and Additive Package D in Table 1 of US2018 / 0355267.

[0121] The deposit control additive composition is preferably present in the diesel fuel composition at a level from 1 ppmw to 1000 ppmw, more preferably from 100 ppmw to 1000 ppmw, SP3167

[0122] 25 even more preferably from 200 ppmw to 700 ppmw, based on the weight of the total diesel fuel composition.

[0123] Diesel base fuel / diesel fuel components

[0124] A diesel fuel composition prepared for use in the present invention may in general be any type of diesel fuel composition suitable for use in a compression ignition (diesel) engine. It may contain, in addition to the deposit control additive composition described above, other standard diesel fuel components. It may, for example, include a major proportion of a diesel base fuel, for instance of the types described below. Again a "major proportion" means typically 85 %w / w or greater based on the overall composition, more suitably 90 or 95 %w / w or greater, most preferably 98 or 99 or 99.5 %w / w or greater.

[0125] Thus, in addition to the deposit control additive composition, a diesel fuel composition prepared for use in the present invention may comprise one or more diesel fuel components of conventional type. Such components will typically comprise liquid hydrocarbon middle distillate fuel oil (s) , for instance petroleum derived gas oils. In general such fuel components may be organically or synthetically derived, and are suitably obtained by distillation of a desired range of fractions from a crude oil. They will typically have boiling points within the usual diesel range of 150 to 410°C or 170 to 370°C, depending on grade and use. Typically the fuel composition will include one or more cracked products, obtained by splitting heavy hydrocarbons.

[0126] A petroleum derived gas oil may for instance be obtained by refining and optionally (hydro) processing a crude petroleum source. It may be a single gas oil stream obtained from such a refinery process or a blend of several gas oil fractions obtained in the refinery process via different processing routes. Examples of such gas oil fractions are SP3167

[0127] 26 straight run gas oil, vacuum gas oil, gas oil as obtained in a thermal cracking process, light and heavy cycle oils as obtained in a fluid catalytic cracking unit and gas oil as obtained from a hydrocracker unit. Such gas oils may be processed in a hydrodesulphurisation (HDS) unit so as to reduce their sulphur content to a level suitable for inclusion in a diesel fuel composition.

[0128] A diesel base fuel may be or comprise a Fischer-Tropsch derived diesel fuel component, typically a Fischer-Tropsch derived gas oil. In the context of the present invention, the term "Fischer-Tropsch derived" means that a material is, or derives from, a synthesis product of a Fischer-Tropsch condensation process. The term "non-Fischer-Tropsch derived" may be interpreted accordingly. A Fischer-Tropsch derived fuel or fuel component will therefore be a hydrocarbon stream in which a substantial portion, except for added hydrogen, is derived directly or indirectly from a Fischer-Tropsch condensation process.

[0129] The Fischer-Tropsch reaction converts carbon monoxide and hydrogen (synthesis gas or syngas) into longer chain, usually paraffinic, hydrocarbons: n (CO+2H2) = (-CH2-) n+nH2O+heat, in the presence of an appropriate catalyst and typically at elevated temperatures (e.g. , 125 to 300° C. , preferably 175 to 250° C. ) and / or pressures (e.g. , 5 to 100 bar, preferably 12 to 50 bar) . Hydrogen : carbon monoxide ratios other than 2:1 may be employed if desired.

[0130] An example of a Fischer-Tropsch based process is the Shell™ "Gas-to-liquids" or "GtL" technology (formerly known as the SMDS (Shell Middle Distillate Synthesis) and described in "The Shell Middle Distillate Synthesis Process", van der Burgt et al, paper delivered at the 5th Synfuels Worldwide Symposium, Washington DC, November 1985, and in the November SP3167

[0131] 27

[0132] 1989 publication of the same title from Shell International Petroleum Company Ltd, London, UK) . In the latter case, preferred features of the hydroconversion process may be as disclosed therein. This process produces middle distillate range products by conversion of a natural gas into a heavy long chain hydrocarbon (paraffin) wax which can then be hydroconverted and fractionated.

[0133] For use herein, a Fischer-Tropsch derived fuel component is preferably any suitable component derived from a gas to liquid synthesis (hereinafter a GtL component) , or a component derived from an analogous Fischer-Tropsch synthesis, for instance converting gas, biomass or coal to liquid (hereinafter an XtL component) . A Fischer-Tropsch derived component is preferably a GtL component. It may be a BtL (biomass to liquid) component. In general a suitable XtL component may be a middle distillate fuel component, for instance selected from diesel and gas oil fractions as known in the art; such components may be generically classed as synthetic process fuels or synthetic process oils. Preferably an XtL component for use as a diesel fuel component is a gas oil.

[0134] In order to produce renewable diesel fuel component via the Fischer-Tropsch process, the carbon monoxide and hydrogen (syngas) may themselves be derived from renewable sources. For example, in one embodiment, the renewable naphtha can be manufactured from renewable natural gas from agricultural, industrial and household wastes via a Fischer-Tropsch process. In another embodiment, the renewable naphtha is manufactured from renewable syngas via a Fischer-Tropsch process, wherein the syngas is derived from 'green' , 'blue' or 'pink' hydrogen, and the carbon dioxide is captured from either an industrial process or directly from the air. In one embodiment, the syngas is derived from 'green' hydrogen SP3167

[0135] 28 which is produced via electrolysis of water by which an electrical current is used to separate the hydrogen from the oxygen in water. In another embodiment, the syngas is derived from 'blue' hydrogen which is a common term for decarbonised hydrogen which is hydrogen that is manufactured by natural has reforming coupled with carbon capture and storage (CCS) . Examples of processes used for this are the Shell Blue Hydrogen Process (SBHP) , steam methane reforming (SMR) and autothermal reforming (ATR) . In another embodiment, the syngas is derived from 'pink' hydrogen which refers to hydrogen which is produced through electrolysis powered by nuclear energy. In yet another embodiment, the renewable naphtha is manufactured from renewable syngas via a Fischer-Tropsch process, wherein the syngas is derived from the gasification of waste biomass or other waste material.

[0136] The Fischer-Tropsch derived diesel fuel may be obtained directly from the Fischer-Tropsch reaction, or derived indirectly from the Fischer-Tropsch reaction, for instance by fractionation of Fischer-Tropsch synthesis products and / or by hydrotreatment of Fischer-Tropsch synthesis products.

[0137] Another diesel base fuel for use herein may be or may comprise a renewable diesel fuel. It may be or contain a so- called "biodiesel" fuel component such as a vegetable oil, hydrogenated vegetable oil or vegetable oil derivative (e.g. a fatty acid ester, in particular a fatty acid methyl ester) or another oxygenate such as an acid, ketone or ester. A preferred renewable diesel fuel for use herein is a renewable paraffinic diesel fuel such as Hydrotreated Esters and Fatty Acids (HEFA) .

[0138] In one embodiment, the diesel fuel composition comprises a diesel base fuel comprising a paraffinic diesel component selected from a Fischer-Tropsch derived paraffinic diesel component, a renewable paraffinic diesel component, and SP3167

[0139] 29 mixtures thereof. In one embodiment herein, the diesel base fuel comprises a Fischer-Tropsch derived paraffinic diesel component. In another embodiment, the diesel base fuel comprises a renewable paraffinic diesel component, especially Hydrotreated Esters and Fatty Acids (HEFA) .

[0140] Diesel fuel components contained in a composition prepared for use in the present invention will typically have a density of from 750 to 900 kg / m3, preferably from 800 to 860 kg / m3, at 15°C (ASTM D-4052 or EN ISO 3675) and / or a VK 40 of from 1.5 to 6.0 mm3 / s (ASTM D-445 or EN ISO 3104) .

[0141] In a diesel fuel composition prepared for use in the present invention, the base fuel may itself comprise a mixture of two or more diesel fuel components of the types described above.

[0142] A diesel fuel composition prepared for use in the present invention will suitably comply with applicable current standard specif ication ( s ) such as for example EN 590 (for Europe) or ASTM D-975 (for the USA) . By way of example, the overall fuel composition may have a density from 820 to 845 kg / m3at 15°C (ASTM D-4052 or EN ISO 3675) ; a T95 boiling point (ASTM D-86 or EN ISO 3405) of 360°C or less; a measured cetane number (ASTM D-613) of 51 or greater; a VK 40 (ASTM D- 445 or EN ISO 3104) from 2 to 4.5 mm3 / s; a sulphur content (ASTM D-2622 or EN ISO 20846) of 50 mg / kg or less; and / or a polycyclic aromatic hydrocarbons (PAH) content (IP 391 (mod) ) of less than 11 %w / w. Relevant specifications may, however, differ from country to country and from year to year, and may depend on the intended use of the fuel composition.

[0143] A diesel fuel composition for use herein suitably contains no more than 5000 ppmw (parts per million by weight) of sulphur, typically from 2000 to 5000 ppmw, or from 1000 to 2000 ppmw, or alternatively up to 1000 ppmw. The composition may, for example, be a low or ultra low sulphur fuel, or a SP3167

[0144] 30 sulphur free fuel, for instance containing at most 500 ppmw, preferably no more than 350 ppmw, most preferably no more than 100 or 50 or even 10 ppmw, of sulphur.

[0145] A diesel fuel composition prepared for use in the present invention, or a diesel base fuel used in such a composition, may be additivated (additive-containing) or unadditivated (additive-free) . If additivated, e.g. at the refinery, it will contain minor amounts of one or more additives selected for example from anti-static agents, pipeline drag reducers, flow improvers (e.g. ethylene / vinyl acetate copolymers or acrylate / maleic anhydride copolymers) , lubricity additives, viscosity index (VI) improvers, antioxidants and wax antisettling agents. Thus, the composition may contain a minor proportion (preferably 1 %w / w or less, more preferably 0.5 %w / w (5000 ppmw) or less and most preferably 0.2 %w / w (2000 ppmw) or less) , of one or more fuel additives, in addition to the deposit control additive composition described above.

[0146] The deposit control additive composition comprising an imide containing quaternary ammonium salt ( 'imide quat' ) is incorporated into a diesel fuel composition by blending with a diesel base fuel, or one or more diesel fuel blending components as described above.

[0147] The invention is illustrated by the following nonlimiting examples. Examples

[0148] Two fuels (Fuels A and B) were tested in order to determine their impact on the diesel particulate filter (DPF) regeneration frequency in a diesel vehicle. All testing was carried out in a Volkswagen Passat 2.0 Euro 6d HOkW. Fuel A was a diesel base fuel. Fuel B was the same as Fuel A except for the addition of 520 ppmw of a fuel additive package / deposit control additive composition comprising an imide quat / deposit control additive. The imide quat was prepared according to the process described in US2017 / 0114296 (see in particular Example 4: Formation of a 550 M (g / mol) , PIBSA / DMAPA Quaternary Ammonium Salt using Propylene Oxide (an imide / propylene oxide quat) .

[0149] The present example can also be carried out using an imide quat prepared according to the process described in Example 15 of US2017 / 0114296 : (Prophetic) — Formation of a Conventional 550 M (g / mol) , PIBSA / DMAPA Quaternary Ammonium Salt using Propylene Oxide (an imide / propylene oxide quat) .

[0150] In order to prepare the deposit control additive composition, the imide quat is combined with other suitable additives, in particular those set out in Additive Package A or Additive Package D in Table 1 of US2018 / 0355267.

[0151] A custom steady-state cycle was developed to evaluate based on distance (km) the frequency of diesel particulate filter (DPF) regeneration events under controlled conditions while operating the vehicle in a randomized matrix with Fuel A and Fuel B. This cycle was designed to operate the vehicle at a constant engine operating point that favored soot formation. Due to the low engine-out exhaust temperature, passive regeneration was not achievable, necessitating active regeneration events.

[0152] To ensure consistency, a pre-conditioning step was included at the beginning of each cycle. This step ensured that the vehicle always started under the same conditions. The temperature during the cycle was controlled to reflect the yearly average temperature of Northern Europe .

[0153] Furthermore, the cycle consisted of a total of four DPF regeneration events, resulting in four regeneration intervals. This was desired as there is an adaptation period from fuel to fuel. The vehicle was operated continuously until all four regeneration events were triggered and measured. This setup simulated typical highway driving - 32 - conditions. The distance required from the last regeneration event to the new regeneration event was recorded. This distance is a critical factor for differentiating between different fuels.

[0154] The results are shown in Table 1 below.

[0155] Table 1 Discussion

[0156] The base fuel (Fuel A) had a lack of significant positive effect on the Diesel Particulate Filter (DPF) regeneration frequency. There is a noticeable influence on the frequency of Diesel Particulate Filter (DPF) regeneration events caused by the addition of the Deposit Control Additive package in the base fuel (Fuel B) . As can be seen from Table 1, for each loading interval, Fuel B required a longer distance to reach the loading interval than Fuel A.

Claims

SP316733C L A I M S1. Use of a deposit control additive composition in a diesel fuel composition, wherein the deposit control additive composition comprises an imide containing quaternary ammonium salt ( 'imide quat' ) , wherein the imide quat comprises the reaction product of:(a) a quaternizable compound that is the reaction product of :(i) a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent has a number average molecular weight ranging from 100 to 10000, and(ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl- substituted acylating agent to form an imide, and further having at least one quaternizable amino group; and(b) a quaternizing agent suitable for converting the quaternizable amino group of the nitrogen containing compound to a quaternary nitrogen, for reducing the measured regeneration frequency of a diesel particulate filter in a vehicle combusting the diesel fuel composition.

2. Use according Claim 2 wherein the quaternizable amino group is a primary, secondary or tertiary amino group .

3. Use according to Claim 1 or 2 wherein the hydrocarbyl-substituting acylating agent comprises at least one polyisobutenyl succinic anhydride or polyisobutenyl succinic acid.

4. Use according to any of Claims 1 to 3 wherein the reaction of (a) (i) with (a) (ii) is carried out at a temperature of greater than 80°C.SP3167345. Use according to any of Claims 1 to 4 wherein the nitrogen containing compound excludes dimethylaminopropylamine .

6. Use according to any of Claims 1 to 5 wherein the quaternizing agent comprises at least one dialkyl sulfate, alkyl halide, hydrocarbyl substituted carbonate, hydrocarbyl epoxide, carboxylate, alkyl ester or mixtures thereof .

7. Use according to any of Claims 1 to 6 wherein the quaternizing agent is a hydrocarbyl epoxide.

8. Use according to any of Claims 1 to 7 wherein the quaternizing agent is a hydrocarbyl epoxide in combination with an acid.

9. Use according to any of Claims 1 to 8 wherein the quaternizing agent is an oxalate or terephthalate.

10. Use according to any of Claims 1 to 9 wherein the quaternizing agent excludes methyl salicylate.

11. Use according to any of Claims 1 to 10 wherein the deposit control additive composition comprises at least one other additive.

12. Use according to Claim 11 wherein the at least one other additive comprises a detergent, a dispersant, a demulsifier, a lubricity agent, a cold flow improver, an antioxidant, or a mixture thereof.

13. Use according to any of Claims 1 to 12 wherein the diesel fuel composition comprises a diesel base fuel.

14. Use according to Claim 13 wherein the diesel base fuel comprises a paraffinic diesel component selected from a Fischer-Tropsch derived paraffinic diesel component or a renewable paraffinic diesel component.

15. Method for reducing the measured regeneration frequency of a diesel particulate filter in a diesel vehicle which comprises a compression ignition internalSP316735 combustion engine and a diesel particulate filter wherein the method comprises (A) fuelling the compression ignition internal combustion engine with a diesel fuel composition comprising a diesel base fuel and a deposit control additive composition, wherein the deposit control additive composition comprises an imide containing quaternary ammonium salt ( 'imide quat' ) , wherein the imide quat comprises the reaction product of:(a) a quaternizable compound that is the reaction product of :(i) a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent has a number average molecular weight ranging from 300 to 750, and(ii) a nitrogen containing compound having a nitrogen atom capable of reacting with said hydrocarbyl- substituted acylating agent to form an imide, and further having at least one quaternizable amino group; and(b) a quaternizing agent suitable for converting the quaternizable amino group of the nitrogen containing compound to a quaternary nitrogen;(B) combusting the diesel fuel composition in the compression ignition internal combustion engine;(C) regenerating the diesel particulate filter while combusting the diesel fuel composition; and(D) comparing the frequency of regeneration of the diesel particulate filter when combusting the diesel fuel composition with the frequency of regeneration of the diesel particulate filter when combusting an analogous diesel fuel composition which does not comprise the deposit control additive composition,Wherein the frequency of regeneration per 1000 miles of the diesel particulate filter when combusting the dieselS P3167- 36 - fuel compos ition comprising the deposit control additive composition i s lower than a frequency of regeneration per 1000 miles of the die sel particulate f ilter when combusting an analogous diesel fuel composition which doe s not comprise the deposit control additive composition .

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