Uses and methods

Abstract

Use of a nitrogen-containing compound as an additive in a diesel fuel composition to reduce the impact of deposits on a post-combustion system of a diesel engine when the diesel fuel composition is combusted. The nitrogen-containing compound comprises at least 4% by mass of nitrogen atoms, and in some embodiments, less than 5 N-H bonds.

Description

[0001] The present invention relates to methods and uses for improving the performance of diesel engines. In particular, the present invention relates to reducing the effects of deposits in the after-combustion system of a diesel engine, especially a modern diesel engine having a high pressure fuel system.

[0002] The addition of detergent additives to clean deposits in diesel engine combustion systems (eg, fuel injection systems) is well known and a variety of detergents have been developed for this purpose.

[0003] Attempts have also been made to reduce deposits in the exhaust gas recirculation system of a diesel engine. However, little work has been done to remove deposits in the afterburning system. However, the presence of deposits in the afterburning system of a diesel engine can have a significant detrimental effect on the performance of the diesel engine, especially modern diesel engines with high pressure fuel systems.

[0004] The afterburning system of a diesel engine typically includes a series of components through which the exhaust gas must flow before exiting the vehicle. The afterburning system may include a turbocharger, a diesel oxidation catalyst, a diesel particulate filter, a selective catalytic reduction unit, and an ammonia oxidation catalyst. It would be desirable to be able to eliminate deposits in any or all of these components.

[0005] The formation of deposits in the afterburning system may involve the accumulation of soot on components of the afterburning system. Specifically, the formation of deposits in the afterburning system may involve the accumulation and / or capture of soot in a diesel particulate filter of the afterburning system.

[0006] Prevent and / or reduce deposits on sensors within the post-combustion system (e.g. NO x Deposits on sensors, temperature sensors and / or pressure sensors) would also be helpful.

[0007] It would also be beneficial to prevent and / or reduce the accumulation of soot on components of an aftercombustion system and / or to prevent and / or remove soot from a diesel particulate filter of an aftercombustion system.

[0008] Surprisingly, the present inventors have discovered that the addition of certain compounds as fuel additives can remove the effects of deposits in the after-combustion system of a diesel engine.

[0009] According to a first aspect of the present invention, there is provided the use of one or more nitrogen-containing compounds as an additive in a diesel fuel composition to reduce the impact of deposits in the after-combustion system of a diesel engine when burning the diesel fuel composition, wherein the one or more nitrogen-containing compounds contain at least 4% by mass nitrogen atoms.

[0010] According to a second aspect of the invention, there is provided a method for reducing the effects of deposits in a diesel engine aftercombustion system, the method comprising burning in the engine a diesel fuel composition comprising one or more nitrogen-containing compounds as additives, wherein the nitrogen-containing compounds comprise at least 4 mass % nitrogen atoms.

[0011] The present invention relates to a method and use for reducing the effects of deposits in an afterburning system. The presence of deposits on one or more components of a diesel engine afterburning system typically has a negative impact on the performance of the engine. Reducing the effects of deposits may involve reducing or preventing the formation of deposits and / or removing existing deposits and / or changing the properties of deposits. Nitrogen-containing compounds may be referred to herein as afterburning deposit control additives.

[0012] Reducing the effects of deposits may involve changing the properties of the deposits. This means that the structure or composition of the deposits formed may be different so as to cause less damage to the performance of the engine, for example by increasing the ignitability and / or thermal conductivity of the deposits. Increasing the ignitability of the deposits may have the advantage of making the deposits easier to remove. When the deposits in question are deposits on a diesel particulate filter in an engine that is configured to regenerate the diesel particulate filter by periodically increasing the temperature of the exhaust gas flowing through the diesel particulate filter, the use of the nitrogen-containing compounds of the present invention may allow the filter to be regenerated using a lower temperature exhaust gas and / or may allow the frequency of the filter regeneration process to be reduced.

[0013] In preferred embodiments, reducing the effects of deposits involves reducing and / or preventing the formation of deposits and / or removing existing deposits.

[0014] In a preferred embodiment, reducing the effects of deposits involves reducing and / or preventing the formation of deposits in an after-combustion system of a diesel engine.

[0015] Thus, a first aspect of the present invention preferably provides the use of a nitrogen containing compound as defined herein as an additive in a diesel fuel composition to reduce the formation of deposits in the after-combustion system of a diesel engine when combusting said diesel fuel composition.

[0016] A second aspect of the invention preferably provides a method of reducing deposit formation in a diesel engine aftercombustion system, the method comprising combusting in the engine a diesel fuel composition comprising as an additive one or more nitrogen containing compounds as defined herein.

[0017] Preferred features of the first and second aspects of the invention will now be described.

[0018] The present invention relates to the use of additives for diesel fuel compositions to reduce the effects of deposits in post-combustion systems. The additive is one or more nitrogen-containing compounds containing at least 4 mass % of nitrogen atoms. Such additives may be referred to herein as post-combustion deposit control additives.

[0019] For the avoidance of doubt, unless otherwise stated, the post-combustion deposit control additive used in the present invention may include a mixture of compounds, and reference to an additive or the additive includes a mixture. In particular, mixtures of isomers and mixtures of homologues are within the scope of the present invention. Those skilled in the art will appreciate that some commercial sources of additive compounds and / or reagents for forming additive compounds described herein may include mixtures of isomers and / or mixtures of homologues.

[0020] The nitrogen-containing compounds used in the present invention contain at least 4% by mass of nitrogen atoms. This means that at least 4% of the molecular weight of the nitrogen-containing compound is provided by nitrogen atoms, preferably by number average molecular weight. The mass content of nitrogen in such compounds can be calculated by standard methods or determined by elemental analysis. Since the nitrogen-containing compound can be a mixture of compounds, for example isomers, homologues and / or structurally similar compounds produced by the reaction used to form the nitrogen-containing compound, the nitrogen mass percentages mentioned above are suitably average values ​​of such a mixture of nitrogen-containing compounds.

[0021] Preferably, the nitrogen-containing compound comprises at least 5 mass % nitrogen atoms, preferably at least 7 mass % or at least 10 mass %.

[0022] Suitably, the nitrogen containing compound comprises at most 50 mass % nitrogen atoms or at most 40 mass %. Suitably, the nitrogen containing compound comprises at most 35 mass % nitrogen atoms, suitably at most 30 mass %.

[0023] Suitably, the nitrogen-containing compound comprises 4 to 50 mass % nitrogen atoms, suitably 4 to 40 mass %. In a preferred embodiment, the nitrogen-containing compound comprises 4 to 35 mass % nitrogen atoms, suitably 5 to 30 mass % or 10 to 30 mass %.

[0024] The present inventors have discovered that the presence of this relatively high proportion of nitrogen atoms in the additive is required to provide the beneficial effects in the diesel engine aftercombustion systems described herein.

[0025] The nitrogen-containing compounds used in the present invention preferably contain no more than 12 NH bonds. NH bonds may be referred to as "free" NH bonds. Preferably, the nitrogen-containing compound contains less than five NH bonds, less than four NH bonds or less than three NH bonds. Preferably, the above-mentioned limit on the number of NH bonds applies only to NH bonds on amino groups in the nitrogen-containing molecule. For example, NH bonds of amide groups and / or NH bonds of nitrogen atoms in aromatic heterocycles are not included in the NH bond limits described herein.

[0026] The present inventors have discovered that this relatively small number of such free NH bonds in an additive containing a relatively high proportion of nitrogen may be required for the nitrogen-containing compound to provide a beneficial effect in the afterburning system of a diesel engine as described herein.

[0027] Suitable nitrogen-containing compounds are the reaction products of a) a hydrocarbyl substituting agent and b) a nitrogen-containing agent.

[0028] In some embodiments, the nitrogen-containing compound is the reaction product of:

[0029] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0030] b) nitrogen-containing reagents;

[0031] As further described below.

[0032] In some embodiments, the nitrogen-containing compound is the reaction product of:

[0033] a) amines or polyamines containing hydrocarbon groups;

[0034] b) nitrogen-containing reagents; and

[0035] c) aldehydes;

[0036] As further described below.

[0037] The nitrogen-containing compound can be a mixture of the reaction product of a) a hydrocarbyl substitution agent and b) a nitrogen-containing agent. For example, the nitrogen-containing compound can include the reaction product of:

[0038] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0039] b) nitrogen-containing reagents;

[0040] and the reaction products of:

[0041] a) amines or polyamines containing hydrocarbon groups;

[0042] b) nitrogen-containing reagents; and

[0043] c) aldehydes;

[0044] As further described below.

[0045] When the nitrogen-containing compound is the reaction product of a) a hydrocarbyl substitution agent and b) a nitrogen-containing agent, the nitrogen-containing agent b) suitably comprises a nitrogen-containing group A. The hydrocarbyl substitution agent a) suitably comprises a hydrocarbyl group R 1 .

[0046] The A group suitably provides a significant amount of the required nitrogen content of the additive, and R 1 The group may be a solubilizing group which provides sufficient solubility for the additive in diesel fuel so that the additive can be used effectively. 1 The group is used to provide the desired nitrogen content of at least 4 mass % in the nitrogen-containing compound.

[0047] In some embodiments, the nitrogen-containing reagent b) suitably comprises a nitrogen-containing heterocyclic group. The heterocyclic group suitably provides a significant amount of the required nitrogen content of the additive. In such embodiments, the A group of the nitrogen-containing reagent b) is a nitrogen-containing heterocyclic group.

[0048] The nitrogen-containing heterocyclic group can be any aromatic or aliphatic heterocyclic group containing at least one nitrogen atom. The nitrogen-containing heterocyclic group can contain other heteroatoms, such as at least one oxygen atom or at least one sulfur atom, preferably at least one oxygen atom. In some embodiments, the nitrogen-containing heterocyclic group does not contain other heteroatoms except nitrogen. The nitrogen-containing heterocyclic group of the A group can be selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, five-membered heterocycle (such as pyrazole or imidazole) or benzo-fused five-membered heterocycle (such as benzimidazole) and derivatives thereof. Suitable selection of nitrogen-containing heterocyclic groups, with R 1 Any additional nitrogen atoms present in the group together provide the required nitrogen content of at least 4 mass %.

[0049] Preferably, the A group is selected from an optionally substituted five-membered nitrogen-containing heterocycle or a benzo-fused five-membered nitrogen-containing heterocycle and derivatives thereof. Preferably, the A group is an optionally substituted benzotriazole, indazole, triazole, tetrazole, imidazole, benzimidazole or imidazoline, or a derivative thereof. Suitable A groups are optionally substituted benzotriazole, benzimidazole, indazole, triazole or tetrazole.

[0050] In some embodiments, the A group is a non-cyclic nitrogen-containing group. In such embodiments, the A group can be an amine or a polyamine. Suitable polyamines can have formula (II):

[0051]

[0052] wherein n is 1 to 10. The nitrogen-containing compound may be a mixed compound having different n numbers in the "A" group. Thus, n is suitably the average of the different n numbers present in the mixture. Thus, n may be a non-integer value, being 1 to 10, i.e. 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4, or 1 to 3.

[0053] Thus, the A group may be provided by ethylenediamine, diethylenetriamine (DETA) or triethylenetetramine (TETA) or tetraethylenepentamine (TEPA). Preferably, the A group is provided by TETA or TEPA.

[0054] R of the hydrocarbon substitution reagent a) 1 The group preferably has a molecular weight (Mn) of at most 1,000, at most 600 or at most 400. 1 The group preferably has a molecular weight of at least 50, at least 100 or at least 150. 1 It preferably has a molecular weight in the range of 50 to 500, preferably 100 to 400 or 150 to 350.

[0055] In some embodiments, R 1 The group is a hydrocarbyl group. The term "hydrocarbyl" as used herein means a group having a carbon atom directly connected to the remainder of the molecule and having mainly aliphatic hydrocarbon characteristics. Suitable hydrocarbyl groups may contain non-hydrocarbon moieties. For example, they may contain up to one non-hydrocarbyl group per ten carbon atoms, as long as the non-hydrocarbyl group does not significantly change the main hydrocarbon characteristics of the group. Those skilled in the art will appreciate that such groups include, for example, hydroxyl, oxygen, halogen (especially chlorine and fluorine), alkoxy, alkyl mercapto, alkyl sulfoxide, etc. Preferred hydrocarbyl substituents are pure aliphatic hydrocarbons in nature and do not contain such groups.

[0056] The hydrocarbyl substituent is preferably predominantly saturated, that is, contains no more than one carbon-carbon unsaturated bond for every ten carbon-carbon single bonds present.

[0057] The hydrocarbyl group preferably contains at least 10 carbon atoms, more preferably at least 14 carbon atoms or at least 18 carbon atoms. Preferably, the hydrocarbyl group contains up to 30 carbon atoms, preferably up to 28 carbon atoms or up to 26 carbon atoms. The hydrocarbyl group may contain 10 to 30 carbon atoms, 14 to 26 carbon atoms, 18 to 26 carbon atoms or more preferably 20 to 24 carbon atoms.

[0058] The hydrocarbyl substituent may be a mixture of hydrocarbyl groups having an average of the above range of carbon atoms. Thus, the molecular weight of the hydrocarbyl group is suitably defined as the number average molecular weight (Mn). The Mn of the hydrocarbyl group is preferably 50 to 500, preferably 100 to 400 or 150 to 350.

[0059] Those skilled in the art will be familiar with standard techniques for measuring number average molecular weight, such as by vapor pressure osmometry, end group titration, proton nuclear magnetic resonance, boiling point elevation, freezing point depression (cryometry), and gel permeation chromatography (GPC).

[0060] The hydrocarbyl substituent may be an olefin having the carbon number and / or Mn as described above.

[0061] Hydrocarbyl substituents can be made from homopolymers or interpolymers (e.g., copolymers, terpolymers) of monoolefins and diolefins having 2 to 10 carbon atoms, such as ethylene, propylene, butane-1, isobutylene, butadiene, isoprene, 1-hexene, 1-octene, etc. Preferably, these olefins are 1-monoolefins. Hydrocarbyl substituents can also be derived from halogenated (e.g., chlorinated or brominated) analogs of such homopolymers or interpolymers. Alternatively, substituents can be made from other sources, such as monomeric high molecular weight olefins (e.g., 1-tetradecene) and their chlorinated and hydrochlorinated analogs, aliphatic petroleum fractions, such as paraffin and its cracked and chlorinated analogs and hydrochlorinated analogs, white oils, synthetic olefins (e.g., produced by Ziegler-Natta process) (e.g., polyethylene grease) and other sources known to those skilled in the art. If desired, any unsaturation in the substituent can be reduced or eliminated by hydrogenation according to procedures known in the art.

[0062] The hydrocarbyl substituent may be a polyisobutylene, preferably having the carbon number and / or Mn described above. Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention. Highly reactive polyisobutylenes are defined herein as polyisobutylenes in which at least 50%, preferably 70% or more, of the terminal olefinic double bonds are of the vinylidene type, as described in EP 0 565 285. Particularly preferred polyisobutylenes are polyisobutylenes having greater than 80 mol % and up to 100% terminal vinylidene groups, such as the polyisobutylenes described in EP 1 344 785.

[0063] Other preferred hydrocarbyl groups include those having an internal olefin, such as those described in applicant's published application WO 2007 / 015080.

[0064] As used herein, internal olefins refer to any olefin containing primarily non-alpha double bonds, i.e., beta or higher olefins. Preferably, such materials are substantially entirely beta olefins or higher olefins, e.g., containing less than 10% by weight of alpha olefins, more preferably less than 5% by weight or less than 2% by weight. Typical internal olefins include Neodene 1518IO available from Shell.

[0065] Internal olefins are sometimes referred to as isomerized olefins and can be prepared from alpha olefins by isomerization processes known in the art, or can be obtained from other sources. The fact that they are also referred to as internal olefins reflects that they do not necessarily have to be prepared by isomerization.

[0066] The reaction of the hydrocarbyl substituent a) with the nitrogen-containing reagent b) is preferably carried out in the presence of a nitrogen-containing group A and a hydrocarbyl R 1 A linking group L is formed between them. The L group can be a bond, an amine, an amide, a succinimide, a succinic acid or an amide of a succinic acid.

[0067] The nitrogen-containing compound is the reaction product of a) a hydrocarbyl substituting agent and b) a nitrogen-containing reagent, which suitably has formula (I):

[0068] ALR 1

[0069] (I)

[0070] in:

[0071] A is a nitrogen-containing group;

[0072] L is a bond or a linking group; and

[0073] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000. Groups A, L and R 1 Preferably as defined above.

[0074] Therefore, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (I).

[0075] In some embodiments, the nitrogen-containing compound is the reaction product of a) a hydrocarbyl substituting agent and b) a nitrogen-containing agent, wherein a) is a hydrocarbyl-substituted carboxylic acylating agent.

[0076] Thus, in such embodiments, the nitrogen-containing compound is preferably the reaction product of:

[0077] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0078] b) Nitrogen-containing reagents.

[0079] In such embodiments, the hydrocarbon group R 1 The linking group L between the nitrogen-containing group A is provided by an amide of succinic acid or a succinic acid derivative, as further described below.

[0080] Suitably, component a) comprises a group R as defined above 1 Suitably, component a) comprises a hydrocarbyl group as defined above, preferably a polyisobutylene or olefin group as defined above.

[0081] Component a) suitably has the formula (aI):

[0082]

[0083] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

[0084] R 1 Preferred are hydrocarbyl groups as described above, preferably having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0085] R 1 It may be a polyisobutylene group or an internal olefin group having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0086] In some embodiments, component a) is polyisobutenyl succinic anhydride. These compounds are commonly referred to as "PIBSA" and are well known to those skilled in the art. Suitably, the polyisobutylene group of the PIBSA is as defined above.

[0087] PIBSA can be prepared by reacting a suitable polyisobutylene with maleic anhydride.

[0088] The preparation of polyisobutenyl substituted succinic anhydrides (PIBSA) is well documented in the art. Suitable methods include thermally reacting polyisobutene with maleic anhydride (see, for example, US-A-3,361,673 and US-A-3,018,250), and reacting halogenated, especially chlorinated polyisobutene (PIB) with maleic anhydride (see, for example, US-A-3,172,892). Alternatively, polyisobutenyl succinic anhydride can be prepared by mixing a polyolefin with maleic anhydride and passing chlorine through the mixture (see, for example, GB-A-949,981).

[0089] In some embodiments, component a) is a PIB having a Mn of 250-270.

[0090] In some embodiments, component a) is alkenyl succinic anhydride. These compounds are commonly referred to as "ASA" and are well known to those skilled in the art. Suitably, the olefin group of ASA is as defined above. Preferably, ASA is C16 to C18 alkenyl succinic anhydride (ASA), such as Pentasize 68.

[0091] The reaction of component a) with component b) suitably forms an amide bond, an imide bond or a mixture thereof.

[0092] Component b) preferably contains reactive amino groups or reactive nitrogen, and the reactive nitrogen is part of a nitrogen-containing heterocyclic compound.

[0093] In some embodiments, component b) includes a nitrogen-containing heterocycle, preferably selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, 2-aminoimidazoline, 5-phenyl-2-aminoimidazoline, 5-methyl-2-aminoimidazole, 5-aminoindazole, 6-aminoindazole, 2-aminobenzimidazole, a five-membered heterocycle or a benzo-fused five-membered heterocycle. Preferably, component b) includes a five-membered heterocycle (e.g., pyrazole or imidazole), a benzo-fused five-membered heterocycle (e.g., benzimidazole), an amino-substituted five-membered heterocycle or an amino-substituted benzo-fused five-membered heterocycle. Preferably, component b) includes benzotriazole, indazole, triazole or tetrazole. Component b) can be selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole.

[0094] In some embodiments, component b) comprises an amine or polyamine compound. Suitable component b) is a polyamine. Suitable component b) has formula (bI):

[0095]

[0096] wherein n is 1 to 10. The nitrogen-containing compound may be a mixed compound having different n numbers in the "A" group. Thus, n is suitably the average of the different n numbers present in the mixture. Thus, n may be a non-integer value, being 1 to 10, i.e. 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4, or 1 to 3.

[0097] Component b) may be selected from ethylenediamine, diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). Component b) may be selected from ethylenediamine, diethylenetriamine (DETA) and triethylenetetramine (TETA).

[0098] Preferably, the nitrogen-containing compound is the reaction product of:

[0099] a) polyisobutenyl succinic anhydride or alkenyl succinic anhydride; and

[0100] b) a polyamine selected from ethylenediamine, diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA); or a nitrogen-containing heterocycle selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole.

[0101] In such embodiments, the nitrogen-containing compound formed by the reaction of a) and b) may have the structure described below, for example as the major component in the mixture of compounds resulting from the reaction.

[0102] The L group of the nitrogen-containing compound of formula (I) can be provided by an amide of succinic acid or a succinic acid derivative. In such embodiments, the nitrogen-containing compound formed by the reaction of a) and b) can have formula (III):

[0103]

[0104] in:

[0105] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0106] A is a nitrogen-containing group; and

[0107] R 2 OH, NH2, OR 4 ,OM,NHR 4 or NR 4 R 5 , or is a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 R is independently selected from optionally substituted C1-6 alkyl or alkenyl. 4 and R 5 Quaternary ammonium groups may be included independently.

[0108] Therefore, in some embodiments, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (III).

[0109] In some preferred embodiments, R 2 is OH, so the L group is the amide of succinic acid.

[0110] R 1 The solubilizing group may be bonded to any carbon atom between the acid group and the amide group. 1 A mixture of isomers that differ in the position of the radicals.

[0111] In such embodiments, R 1 Preferred are hydrocarbyl groups as described above, preferably having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0112] In such embodiments, R 1 It may be a polyisobutylene group or an internal olefin group having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0113] In some embodiments of the nitrogen-containing compound of formula (III), the nitrogen-containing group A can be selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, five-membered heterocycle such as pyrazole or imidazole or benzo-fused five-membered heterocycle such as benzimidazole, and derivatives thereof. Preferably, the A group is selected from optionally substituted five-membered heterocycle or benzo-fused five-membered heterocycle, or derivatives thereof. Preferably, the A group is optionally substituted benzotriazole, indazole, triazole or tetrazole.

[0114] In such an embodiment, the A group is suitably tetrazole. Thus, the nitrogen-containing compound may preferably have the formula (IV):

[0115]

[0116] Where R 1 and R 2 As defined above.

[0117] In such embodiments, the compound of formula (IV) may also exist in the form of an imide having formula (IVb):

[0118]

[0119] In such embodiments, the nitrogen-containing compound may have formula (IVc), which is an isomer of formula (IV):

[0120]

[0121] Where R 1 and R 2 As defined above.

[0122] In such embodiments, the nitrogen-containing compound may be a mixture of compounds of formula (IV), (IVb), and (IVc).

[0123] In such embodiments, R 2 Preferably OH or O - X + , wherein X is a cation, such as a metal cation such as an ammonium ion.

[0124] In such embodiments, R 1 Preferred are hydrocarbyl groups having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0125] For example, R 1 It may be polyisobutylene or an olefin having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0126] In some embodiments, R 1is a polyisobutylene group, so the nitrogen-containing compound has the formula (IV-A), (IVb-A) or (IVc-A), or a mixture thereof:

[0127]

[0128] wherein n is from 1 to 3. The nitrogen-containing compound may be a mixed compound having different n numbers in the polyisobutylene group. Thus, n is suitably the average of the different n numbers present in the mixture. Thus, n may be a non-integer value, from 1 to 3, i.e., such that n is from 1.0 to 3.0.

[0129] In some embodiments, R 1 is a C10-24 olefin group, preferably a C12-22 olefin group or a C16-18 olefin group. In such embodiments, the nitrogen-containing compound may have formula (IV-B), (IVb-B) or (IVc-B), or a mixture thereof:

[0130]

[0131] Each R 3 is an alkyl group and is independently selected to provide an R having 12 to 22 carbon atoms 1 Group.

[0132] In some embodiments of the nitrogen-containing compound of formula (III), the A group is a non-cyclic nitrogen-containing group as described above, such as an amine or polyamine group. In such embodiments, the main component of the nitrogen-containing compound can be a cyclic imide, wherein R 2 is a bond to the A group, suitably a bond to the amine group of the A group. Thus the nitrogen-containing compound may have formula (IIIb)

[0133]

[0134] Where R 1 As defined above.

[0135] In such an embodiment, the A group may be polyethyleneimine. Thus the nitrogen-containing compound may have formula (V):

[0136]

[0137] wherein n is 1 to 10. The nitrogen-containing compound may be a mixed compound having different n numbers in the "A" group. Thus, n is suitably the average of the different n numbers present in the mixture. Thus, n may be a non-integer value, being 1 to 10, i.e. 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4, or 1 to 3.

[0138] In such embodiments, the nitrogen-containing compound may include some ring-opened analogs having formula (Vb):

[0139]

[0140] Where R 2 Preferably OH or O - X + , wherein X is a cation, such as a metal cation or an ammonium ion.

[0141] In such embodiments of compounds of Formula (V) and / or (Vb), R 1 Preferred are hydrocarbyl groups having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0142] For example, R 1 It may be polyisobutylene or an olefin having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0143] In some embodiments, R 1 is a polyisobutylene group, so the nitrogen-containing compound has the formula (VA) and / or (Vb-A):

[0144]

[0145] wherein n is 1 to 10; and wherein m is 1 to 3. Preferably, n is 1 to 4 or 1 to 3. As described above, n and m may be average values, wherein there are mixtures of compounds containing different n and m numbers. Thus, n and m may be non-integer values ​​representing average values, i.e., n is 1.0 to 10.0; and wherein m is 1.0 to 3.0.

[0146] In some embodiments, R 1 It is a C10-24 olefin group, preferably a C12-22 olefin group or a C16-18 olefin group. Therefore, the nitrogen-containing compound has the formula (VB) and / or the formula (Vb-B) or a mixture thereof:

[0147]

[0148] wherein n is from 1 to 10 and may be a non-integer average; and

[0149] Each R 3 is an alkyl group and is independently selected to provide an R having 12 to 22 carbon atoms 1 Preferably, n is 1 to 4 or 1 to 3.

[0150] In some embodiments of the present invention, the nitrogen-containing compound is the reaction product of a) a hydrocarbyl substitution reagent and b) a nitrogen-containing reagent, wherein a) is an amine or polyamine containing a hydrocarbyl group. In such embodiments, the nitrogen-containing compound can be the product of a Mannich reaction involving an aldehyde. Thus, the nitrogen-containing compound can be the reaction product of:

[0151] a) amines or polyamines containing hydrocarbon groups;

[0152] b) nitrogen-containing reagents; and

[0153] c) Aldehydes.

[0154] In such embodiments, the hydrocarbon group R 1 The connection between the group L and the nitrogen-containing group A is provided by a bond, as further described below.

[0155] Suitably, component a) comprises a group R as defined above 1 Suitably, component a) is an alkylamine as defined above, preferably having the formula NHR 7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. Therefore, component a) is preferably a dialkylamine. Preferably, R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl group may be branched, straight chain or cyclic alkyl. Preferably branched or straight chain alkyl. Preferably R 7 and R 8 The same and selected from C1-20 alkyl, preferably C2-20 alkyl.

[0156] Component a) may be selected from diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, bis(2-ethylhexyl)amine or dicocoalkylamine.

[0157] Component b) is preferably a nitrogen-containing reagent comprising a nitrogen-containing heterocycle. Preferably, component b) is selected from an optionally substituted five-membered nitrogen-containing heterocyclic compound or a benzo-fused five-membered nitrogen-containing heterocyclic compound. Preferably, component b) is selected from an optionally substituted triazole, tetrazole, indole, indazole or benzotriazole. Preferably, component b) is selected from triazole, tetrazole, indole, indazole or benzotriazole, preferably triazole, tetrazole or benzotriazole.

[0158] Component c) is suitably an aliphatic aldehyde. Preferably, the aldehyde has from 1 to 10 carbon atoms. Most preferably, the aldehyde is formaldehyde or a source of formaldehyde.

[0159] In a preferred embodiment, the nitrogen-containing compound is the reaction product of:

[0160] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0161] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and

[0162] c) Formaldehyde or a formaldehyde source.

[0163] In such embodiments, the nitrogen-containing compound formed by the reaction of a), b), and c) may have the structure described below, for example as the major component in the mixture of compounds resulting from the reaction.

[0164] In some embodiments of the present invention, in the nitrogen-containing compound of formula (I), L may be a bond. In such embodiments, the nitrogen-containing compound may have formula (VI):

[0165]

[0166] in:

[0167] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0168] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH, which may be optionally substituted where appropriate; and

[0169] The compound optionally comprises a cycloalkyl or aromatic ring connecting Y and Z.

[0170] Therefore, in some embodiments, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (VI).

[0171] R 1 The solubilizing group may be bonded to any suitable atom of the nitrogen-containing heterocyclic group. 1 A mixture of isomers having different radical positions. 1 Combined with the nitrogen of the nitrogen-containing heterocyclic group.

[0172] In this embodiment, R 1 Preferred are aminoalkyl groups having a molecular weight (Mn) of up to 1,000. The molecular weight (Mn) of the aminoalkyl group is preferably from 50 to 500, preferably from 50 to 350 or from 50 to 300.

[0173] R 1 May have the formula -CH2NR7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl group may be a branched or straight chain alkyl group. Preferably R 7 and R 8 are the same and are selected from C1-20 alkyl, preferably C2-20 alkyl. 7 and R 8 Each is independently selected from C1-12 alkyl, preferably C2-10 alkyl.

[0174] In some embodiments of the nitrogen-containing compound of formula (VI), the heterocyclic group is an optionally substituted five-membered nitrogen-containing heterocycle. In such embodiments, W, X, Y and Z are each independently selected from CH, C, N and NH. In such embodiments, the heterocyclic group is preferably selected from an optionally substituted triazole or tetrazole. For example, the nitrogen-containing compound can have formula (VII):

[0175]

[0176]

[0177] Where R 7 and R 8 Each is independently selected from optionally substituted C1-20 alkyl, preferably optionally substituted C2-20 alkyl. 7 and R 8 Each is independently selected from optionally substituted C1-12 alkyl, preferably selected from optionally substituted C2-10 alkyl.

[0178] The nitrogen-containing compound may have the formula (VIIIa) and / or (VIIIb) or a mixture thereof:

[0179]

[0180] Where R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The nitrogen-containing compound may be a mixture of these compounds. For example, the nitrogen-containing compound may be a mixture of compounds of formula (VIII) and (VIIIb) in a ratio of 1:10 to 10:1, suitably 1:5 to 5:1,

[0181] In some embodiments of the nitrogen-containing compound of formula (VI), the heterocyclic group is an optionally substituted benzo-fused five-membered nitrogen-containing heterocyclic ring. In such embodiments, the nitrogen-containing compound has formula (IX):

[0182]

[0183] in:

[0184] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0185] W and X are each independently selected from C and N; and

[0186] Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

[0187] Preferably, each R 6 For H.

[0188] In this embodiment, R 1 Preferred are aminoalkyl groups having a molecular weight (Mn) of up to 1,000. The molecular weight (Mn) of the aminoalkyl group is preferably from 50 to 500, preferably from 50 to 350 or from 50 to 300.

[0189] As mentioned above, R 1 Preferably, the compound has the formula -CH2NR 7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl group may be a branched alkyl, a straight chain alkyl or a cyclic alkyl. Preferably, it is a branched alkyl or a straight chain alkyl. Preferably, R 7 and R 8 The same and selected from C1-20 alkyl, preferably C2-20 alkyl.

[0190] Thus the nitrogen-containing compound may have the formula (X):

[0191]

[0192] in:

[0193] W and X are each independently selected from C and N;

[0194] Each R 6 are independently selected from H, C1-6 alkyl or C1-6 alkenyl; and

[0195] R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl.

[0196] In some embodiments, the nitrogen-containing heterocycle is an optionally substituted benzotriazole, and the nitrogen compound has the formula (XI):

[0197]

[0198] in:

[0199] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0200] Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

[0201] In a preferred embodiment, the nitrogen compound has the formula (XII):

[0202]

[0203] in:

[0204] Each R 6 are independently selected from H, C1-6 alkyl or C1-6 alkenyl; and

[0205] R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl.

[0206] The nitrogen-containing compounds used in the first and second aspects of the present invention may be present in an additive composition. The additive composition may contain other components in addition to one or more nitrogen-containing compounds. For example, the additive composition may include a solvent and / or other fuel additives, as further described below.

[0207] Thus, the present invention may provide the use of an additive composition comprising a nitrogen-containing compound as an additive in a diesel fuel composition to reduce the effects of deposits in the after-combustion system of a diesel engine when the diesel fuel composition is combusted, wherein the nitrogen-containing compound comprises at least 4 mass % nitrogen atoms.

[0208] Similarly, the present invention may provide a method of reducing the effects of deposits in a diesel engine aftercombustion system, the method comprising combusting in the engine a diesel fuel composition comprising an additive composition, wherein the additive composition comprises a nitrogen-containing compound comprising at least 4 mass % nitrogen atoms.

[0209] Preferably, the additive composition comprises at least 20 wt% nitrogen-containing compound, preferably at least 30 wt% or at least 45 wt% nitrogen-containing compound.

[0210] In such an embodiment, it may be convenient to refer to the mass percentage of nitrogen atoms in the entire additive composition. Most of the nitrogen content in the additive composition is suitably provided by nitrogen-containing compounds. Preferably, the additive composition comprises at least 5 mass % nitrogen atoms, preferably at least 6 mass % or at least 7 mass %.

[0211] Suitably, the additive composition comprises up to 35 mass % nitrogen atoms, suitably up to 30 mass % or up to 25 mass %.

[0212] In a preferred embodiment the additive composition comprises from 4 to 35 mass % nitrogen atoms, suitably from 5 to 30 mass % or from 6 to 25 mass %.

[0213] In such an embodiment, the additive composition can be a direct product of a reaction for forming a nitrogen-containing compound. Due to the reaction for forming a nitrogen-containing compound, this direct product may contain other components. Therefore, the additive composition may include a solvent, such as a relatively low volatility solvent, by-products of the reaction, unreacted starting materials, and isomers or analogs of the nitrogen-containing compound formed in the reaction. The reaction can be as described above, i.e., a reaction of components a) and b) or a reaction of components a), b) and c).

[0214] In some embodiments, the additive composition may contain additional components that are subsequently added to the reaction to form the nitrogen-containing compound. For example, the additive composition may include additional solvents or additional fuel additives, as described in more detail below.

[0215] In summary, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably a reaction product of the following substances:

[0216] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0217] b) nitrogen-containing reagents;

[0218] or the reaction product of:

[0219] a) amines or polyamines containing hydrocarbon groups;

[0220] b) nitrogen-containing reagents; and

[0221] c) Aldehydes.

[0222] The nitrogen-containing compound used in the first and second aspects of the present invention is preferably the reaction product of the following substances:

[0223] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0224] b) nitrogen-containing reagents;

[0225] It has the formula (III):

[0226]

[0227] in:

[0228] A is a nitrogen-containing group;

[0229] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0230] R 2 OH, NH2, OR 4 ,OM,NHR 4 or NR 4 R 5 , or is a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 Independently selected from optionally substituted C1-6 alkyl or alkenyl, and may independently contain a quaternary ammonium group;

[0231] or the reaction product of:

[0232] a) amines or polyamines containing hydrocarbon groups;

[0233] b) nitrogen-containing reagents; and

[0234] c) aldehydes;

[0235] It has formula (VI):

[0236]

[0237] in:

[0238] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0239] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and

[0240] The compound optionally comprises a cycloalkyl or aromatic ring connecting Y and Z.

[0241] The nitrogen-containing compound used in the first and second aspects of the present invention is suitably of formula (I):

[0242] ALR 1

[0243] (I)

[0244] in:

[0245] A is a nitrogen-containing group;

[0246] L is a bond or a linking group; and

[0247] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0248] Where A is selected from:

[0249] 1) optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocycle (eg, pyrazole or imidazole), or a benzo-fused five-membered heterocycle (eg, benzimidazole); or

[0250] 2) A non-cyclic nitrogen-containing group having formula (II):

[0251]

[0252] Wherein n is 1 to 10.

[0253] The nitrogen-containing compound used in the first and second aspects of the present invention preferably has the formula (III):

[0254]

[0255] in:

[0256] A is a nitrogen-containing group;

[0257] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0258] R 2 OH, NH2, OR 4 ,OM,NHR 4 or NR 4 R 5 , or is a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 are independently selected from optionally substituted C1-6 alkyl or alkenyl, and R 4 and R 5 may independently contain quaternary ammonium groups;

[0259] Or having formula (VI):

[0260]

[0261] in:

[0262] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0263] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and wherein the compound optionally comprises a cycloalkyl or aromatic ring connecting Y and Z.

[0264] According to a third aspect of the present invention, there is provided a fuel additive composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compound comprises at least 4 mass % of nitrogen atoms.

[0265] The nitrogen-containing compound of the fuel additive composition of the third aspect may have any suitable features and advantages described above in relation to the nitrogen-containing compounds used in the first and second aspects.

[0266] The nitrogen-containing compound preferably contains less than five NH bonds.

[0267] In some embodiments, the nitrogen-containing compound is a compound of formula (I):

[0268] ALR 1

[0269] (I)

[0270] in:

[0271] A is a nitrogen-containing group;

[0272] L is a bond or a linking group; and

[0273] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0274] Where A is selected from:

[0275] 1) optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocycle (eg, pyrazole or imidazole), or a benzo-fused five-membered heterocycle (eg, benzimidazole); or

[0276] 2) A non-cyclic nitrogen-containing group having formula (II):

[0277]

[0278]

[0279] Wherein n is 1 to 10.

[0280] The fuel additive composition may have any suitable features and advantages described above in relation to the additive composition used in the first and second aspects.

[0281] In some embodiments of the third aspect, the nitrogen-containing compound is one or more of:

[0282] A) The reaction product of:

[0283] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0284]

[0285] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0286] b) a nitrogen-containing reagent selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole;

[0287] and

[0288] C) the reaction product of:

[0289] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0290] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and.

[0291] c) Formaldehyde or a formaldehyde source.

[0292] The nitrogen containing compound is suitably present in the fuel additive composition in an amount of from 1 to 60 wt %, suitably from 2 to 50 wt % or from 5 to 45 wt %, based on the weight of the fuel additive composition.

[0293] The detergent additive comprised in the fuel additive composition of the third aspect is suitably provided by one or more of:

[0294] (i) quaternary ammonium salt additives;

[0295] (ii) products of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol;

[0296] (iii) the reaction product of a carboxylic acid derived acylating agent and an amine;

[0297] (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine;

[0298] (v) salts formed by the reaction of carboxylic acids with di-n-butylamine or tri-n-butylamine;

[0299] (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine compound or salt, said product comprising at least one aminotriazole group; and

[0300] (vii) Substituted polycyclic aromatic detergent additives.

[0301] Preferably, the detergent additive is selected from one or more of the following:

[0302] (i) quaternary ammonium salt additives;

[0303] (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and

[0304] (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

[0305] The ratio of nitrogen-containing compound to cleaning agent is suitably from 9:1 to 1:9, preferably from 5:1 to 1:5, preferably from 2:1 to 1:2.

[0306] Preferably, the detergent additive is selected from one or more compounds (iii) reaction products of a hydrocarbyl-substituted carboxylic acid derived acylating agent and an amine.

[0307] The preferred hydrocarbyl substituted acylating agent is polyisobutenyl succinic anhydride.These compounds are commonly referred to as "PIBSA" and are well known to those skilled in the art.

[0308] Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention.

[0309] Particularly preferred PIBSAs are those having a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 1300.

[0310] In a preferred embodiment, the reaction product of a hydrocarbyl-substituted carboxylic acid derived acylating agent and an amine comprises at least one primary or secondary amine group.

[0311] Preferred acylated nitrogen compounds for use herein are prepared by reacting a polyisobutylene-substituted succinic acid-derived acylating agent (e.g., anhydrides, acids, esters, etc.) with a mixture of ethylene polyamines, wherein the polyisobutylene substituent has a number average molecular weight (Mn) of 170 to 2800, and the ethylene polyamines have 2 to about 9 amino nitrogen atoms, preferably about 2 to about 8 nitrogen atoms, and about 1 to about 8 ethylene groups per ethylene polyamine. These acylated nitrogen compounds are suitably formed by reacting an acylating agent: amino compound in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, and most preferably 2:1 to 1:1. In a particularly preferred embodiment, the acylated nitrogen compound is formed by reacting an acylating agent with an amino compound in a molar ratio of 1.8:1 to 1:1.2, preferably 1.6:1 to 1:1.2, more preferably 1.4:1 to 1:1.1, and most preferably 1.2:1 to 1:1. Acylated amino compounds of this type and their preparation are well known to the person skilled in the art and are described, for example, in EP 0 565 285 and US Pat. No. 5,925,151.

[0312] In some preferred embodiments, the composition comprises a cleaning agent of the type formed by the reaction of an acylating agent derived from a polyisobutylene-substituted succinic acid and a polyethylene polyamine. Suitable compounds are described, for example, in WO2009 / 040583.

[0313] A particularly preferred detergent additive is the reaction product of a carboxylic acid derived acylating agent and an amine, wherein the detergent additive is the reaction product of PIBSA and tetraethylenepentamine (TEPA), wherein the PIBSA has a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 130.

[0314] In some preferred embodiments, the detergent additive is selected from one or more compound (i) quaternary ammonium salt additives.

[0315] To form the quaternary ammonium salt additive (i), the nitrogen-containing substance having a tertiary amine group is reacted with a quaternizing agent.

[0316] The quaternizing agent may suitably be selected from esters and non-esters.

[0317] Preferred quaternizing agents for use herein include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate, and styrene oxide or propylene oxide, optionally in combination with an additional acid.

[0318] Particularly preferred quaternary ammonium salt detergent additives for use herein are formed from the reaction of methyl salicylate or dimethyl oxalate with the reaction product of a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight (Mn) of 700 to 1300 and dimethylaminopropylamine.

[0319] The detergent additive is suitably present in the fuel additive composition in an amount of from 1 to 60 wt %, suitably from 2 to 50 wt % or from 5 to 45 wt %, based on the weight of the fuel additive composition.

[0320] According to a fourth aspect of the present invention, there is provided a diesel fuel composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compound comprises at least 4 mass % nitrogen atoms.

[0321] The nitrogen-containing compound and detergent additive of this fourth aspect are as described above in relation to the first, second and third aspects of the invention.

[0322] The nitrogen-containing compound used in the first and second aspects of the invention is suitably a post-combustion deposit control additive. The post-combustion deposit control additive is present in the diesel fuel composition in an amount of at least 1 ppm, preferably at least 10 ppm, more preferably at least 20 ppm, suitably at least 30 ppm, preferably at least 40 ppm, for example at least 50 ppm or at least 60 ppm.

[0323] Suitably, the post combustion deposit control additive is present in the diesel fuel composition in an amount of up to 20000 ppm, suitably up to 10000 ppm, preferably up to 9000 ppm, suitably up to 8000 ppm, for example up to 7000 ppm.

[0324] In some preferred embodiments, the post combustion deposit control additive is present in the diesel fuel composition in an amount less than 1000 ppm, preferably less than 700 ppm, more preferably less than 500 ppm, suitably less than 400 ppm, for example less than 350 ppm or less than 300 ppm.

[0325] In some embodiments, the post combustion deposit control additive is present in the diesel fuel composition in an amount from 50 to 6000 ppm.

[0326] In some embodiments, the post combustion deposit control additive is present in the diesel fuel composition in an amount from 50 to 3000 ppm, more preferably from 50 to 2000 ppm.

[0327] In some embodiments, the post combustion deposit control additive is present in the diesel fuel composition in an amount from 50 to 750 ppm.

[0328] Preferably, the post combustion deposit control additive is present in the diesel fuel composition in an amount of from 50 to 350 ppm.

[0329] In some particularly preferred embodiments, the post combustion deposit control additive is present in the diesel fuel composition in an amount of 50 to 300 ppm.

[0330] In this specification, any reference to ppm refers to parts per million by weight.

[0331] The diesel fuel composition used in the present invention may contain a mixture of two or more post combustion deposit control additives. In such embodiments, the above amounts refer to the total amount of all such additives present in the composition.

[0332] Post-combustion deposit control additives can be added to diesel fuel at any convenient point in the supply chain. For example, the additive can be added to the fuel at a refinery, at a distribution terminal, or after the fuel has left a distribution terminal. If the additive is added to the fuel after the fuel has left a distribution terminal, this is known as an aftermarket application. Aftermarket applications include situations where the additive is added to the fuel in a transportation tank truck, directly to a customer's bulk storage tank, or directly to the end user's vehicle tank. Aftermarket applications may include supplying the fuel additive in a vial suitable for direct addition to a fuel storage tank or vehicle tank.

[0333] Diesel fuel is defined as any fuel suitable for use in a diesel engine, whether for on-road or off-road use. This includes, but is not limited to, fuels described as diesel, marine diesel, heavy fuel oil, industrial fuel oil, etc.

[0334] The diesel fuel composition used in the present invention may include petroleum-based fuel oils, especially middle distillate fuel oils. Such distillate fuel oils generally have a boiling point of 110° C. to 500° C., such as 150° C. to 400° C. The diesel fuel may include atmospheric or vacuum distillates, cracked gas oil, or a blend of straight run and refinery streams (e.g., thermal and / or catalytic cracking and hydrocracking fractions) in any proportion.

[0335] The diesel fuel composition may include non-renewable Fischer-Tropsch fuels, such as those described as GTL (gas-to-liquids) fuels, CTL (coal-to-liquids) fuels, and OTL (oil sands-to-liquids) fuels.

[0336] The diesel fuel composition may comprise a renewable fuel, such as a biofuel composition or a biodiesel composition.

[0337] Diesel fuel compositions can comprise first generation biodiesel.First generation biodiesel contains esters such as vegetable oil, animal fat and waste edible fat or oil.This form of biodiesel can be obtained by the transesterification of oil and alcohol (usually monohydric alcohol) usually carried out in the presence of a catalyst, and the oil is for example rapeseed oil, soybean oil, canola oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow, coconut oil, jatropha oil (jatropha oil), sunflower oil, waste edible oil, hydrogenated vegetable oil or any mixture thereof.

[0338] The diesel fuel composition may include second generation biodiesel. Second generation biodiesel is derived from renewable resources such as vegetable oils and animal fats, and is typically processed in a refinery, for example using hydroprocessing such as the H-Bio process developed by Petrobras. Second generation biodiesel may be similar in properties and quality to petroleum-based fuel oil streams, such as renewable diesel produced from vegetable oils, animal fats, etc. and sold by ConocoPhillips under the name Renewable Diesel and Neste under the name NExBTL.

[0339] The diesel fuel composition may comprise third generation biodiesel. Third generation biodiesel utilizes gasification and Fischer-Tropsch technologies, including those known as BTL (biomass to liquid) fuels. Third generation biodiesel is not much different from some second generation biodiesels, but is designed to utilize whole plants (biomass), thereby expanding the feedstock base.

[0340] In some embodiments, the diesel fuel composition may include a pyrolysis oil, such as a plastic pyrolysis oil or a biomass (wood, vegetable oil, algae) pyrolysis oil.

[0341] The diesel fuel composition may contain a mixture of any or all of the above diesel fuel compositions.

[0342] In some embodiments, the diesel fuel composition can be a mixed diesel fuel comprising biodiesel. In such blends, biodiesel can exist in an amount of, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99% at the most.

[0343] In some embodiments, the fuel composition may comprise pure biodiesel.

[0344] In some preferred embodiments, the fuel composition comprises at least 5 wt. % biodiesel.

[0345] In some embodiments, the fuel composition may include a GTL fuel or be pure GTL fuel.

[0346] In some embodiments, the diesel fuel composition may contain a secondary fuel, such as ethanol. Preferably, however, the diesel fuel composition does not contain ethanol.

[0347] The diesel fuel composition used in the present invention may contain a relatively high sulphur content, for example greater than 0.05 wt%, such as 0.1 wt% or 0.2 wt%.

[0348] However, in a preferred embodiment, the sulphur content of the diesel fuel composition is at most 0.05 wt%, more preferably at most 0.035 wt%, in particular at most 0.015 wt%. Fuels with even lower sulphur contents are also suitable, for example fuels with less than 50 wtppm, preferably less than 20 wtppm, for example 10 wtppm or less sulphur.

[0349] The diesel fuel composition used in the present invention preferably comprises at least 5 wt% biodiesel and less than 50 ppm sulphur.

[0350] Various metal species may be present in diesel fuel compositions. This may be due to contamination of the fuel during manufacture, storage, transport or use, or due to contamination of fuel additives. Metal species may also be intentionally added to the fuel. For example, transition metals are sometimes added as fuel-borne catalysts to improve the performance of diesel particulate filters.

[0351] Other metal-containing species may also be present as contaminants, for example, by acidic species present in the fuel or from lubricating oils that corrode metal and metal oxide surfaces. During use, fuels (e.g., diesel) often come into contact with metal surfaces, for example, in vehicle refueling systems, fuel tanks, fuel transportation vehicles, etc. Typically, metal-containing contaminants may include transition metals, such as zinc, iron, and copper; Group I or Group II metals and other metals, such as lead.

[0352] In addition to the metal-containing contaminants that may be present in diesel fuel, metal-containing materials are sometimes intentionally added to the fuel. For example, as is known in the art, metal-containing fuel-borne catalyst materials may be added to aid in the regeneration of particulate traps. The presence of such catalysts may also lead to injector deposits when the fuel is used in a diesel engine with a high-pressure fuel system.

[0353] Metal-containing contaminants may be in the form of insoluble particles or soluble compounds or complexes, depending on their source. Metal-containing fuel-borne catalysts are usually soluble compounds or complexes or colloidal substances.

[0354] In some embodiments, the diesel fuel may include a metal-containing substance comprising a fuel-borne catalyst. Preferably, the fuel-borne catalyst comprises one or more metals selected from iron, cerium, platinum, manganese, Group I and Group II metals (e.g., calcium and strontium). Most preferably, the fuel-borne catalyst comprises a metal selected from iron and cerium.

[0355] Typically, the total amount of all metal-containing species in the diesel fuel, expressed as the total weight of metals in the species, is from 0.1 to 50 ppm by weight, such as from 0.1 to 20 ppm by weight, preferably from 0.1 to 10 ppm by weight, based on the weight of the diesel fuel.

[0356] The diesel fuel composition used in the present invention may include one or more other additives, such as those common in the diesel fuel. These include, for example, antioxidants, dispersants, detergents, metal deactivation compounds, wax anti-settling agents, cold flow improvers, cetane number improvers, demisters, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal deactivators, odor masking agents, drag reducers and conductivity improvers. The examples of the appropriate amounts of these types of additives will be known to those skilled in the art.

[0357] Suitable cetane number improvers can be selected from C2-24 alkyl nitrates and dialkyl peroxides, preferably decyl nitrate, 2-ethylhexyl nitrate and di-tert-butyl peroxide. Such cetane number improvers are suitably used in concentrations of 50-6,000 ppm, preferably 50-750 ppm, based on the diesel fuel composition.

[0358] In some preferred embodiments, the diesel fuel composition of the present invention comprises one or more detergents. Preferably, the detergent is a nitrogen-containing detergent.

[0359] The one or more cleaning agents may be selected from:

[0360] (i) quaternary ammonium salt additives;

[0361] (ii) products of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol;

[0362] (iii) the reaction product of a carboxylic acid derived acylating agent and an amine;

[0363] (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine;

[0364] (v) salts formed by the reaction of carboxylic acids with di-n-butylamine or tri-n-butylamine;

[0365] (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine compound or salt, said product comprising at least one aminotriazole group; and

[0366] (vii) Substituted polyaromatic detergent additives.

[0367] Preferably, the one or more cleaning agents are selected from one or more of the following:

[0368] (i) quaternary ammonium salt additives;

[0369] (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and

[0370] (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

[0371] Suitable ratios of post-combustion deposit control additive to detergent are from 9:1 to 1:9, preferably from 5:1 to 1:5, preferably from 2:1 to 1:2.

[0372] In some embodiments, the diesel fuel composition further comprises (i) a quaternary ammonium salt additive.

[0373] The quaternary ammonium salt additive is preferably the reaction product of a nitrogen-containing substance having at least one tertiary amine group and a quaternizing agent.

[0374] The nitrogen-containing substance may be selected from:

[0375] (x) 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;

[0376] (y) a Mannich reaction product comprising a tertiary amine group; and

[0377] (z) Polyalkylene-substituted amines having at least one tertiary amine group.

[0378] Examples of quaternary ammonium salts and methods of making them are described in the following patents, which are incorporated herein by reference: US2008 / 0307698, US2008 / 0052985, US2008 / 0113890, and US2013 / 031827.

[0379] The preparation of some suitable quaternary ammonium salt additives, in which the nitrogen-containing substance comprises component (x), is described in WO2006 / 135881 and WO2011 / 095819.

[0380] Component (y) is a Mannich reaction product with a tertiary amine. The preparation of quaternary ammonium salts formed from nitrogen-containing substances including component (y) is described in US 2008 / 0052985.

[0381] The preparation of quaternary ammonium salt additives in which the nitrogen-containing substance comprises component (z) is described, for example, in US 2008 / 0113890.

[0382] To form the quaternary ammonium salt additive (i), the nitrogen-containing substance having a tertiary amine group is reacted with a quaternizing agent.

[0383] The quaternizing agent may suitably be selected from esters and non-esters.

[0384] Preferred quaternizing agents for use herein include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate, and styrene oxide or propylene oxide, optionally in combination with an additional acid.

[0385] Particularly preferred additional quaternary ammonium salts for use herein are formed from methyl salicylate or dimethyl oxalate reacted with the reaction product of a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight (Mn) of 700 to 1300 and dimethylaminopropylamine.

[0386] Other suitable quaternary ammonium salts include quaternized terpolymers such as those described in US2011 / 0258917; quaternized copolymers such as those described in US2011 / 0315107; and acid-free quaternized nitrogen compounds disclosed in US2012 / 0010112.

[0387] Further suitable quaternary ammonium compounds suitable for use in the present invention include the quaternary ammonium compounds described in the applicant's co-pending applications WO2011095819, WO2013 / 017889, WO2015 / 011506, WO2015 / 011507, WO2016 / 016641 and PCT / GB2016 / 052312.

[0388] In some embodiments, the diesel fuel composition used in the present invention comprises 1 to 500 ppm, preferably 50 to 250 ppm of the quaternary ammonium salt additive (i).

[0389] In some embodiments, the diesel fuel composition further comprises (ii) a product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol. The Mannich reaction product is suitably not a quaternary ammonium salt.

[0390] Preferably, the aldehyde component used to prepare the Mannich additive is an aliphatic aldehyde. Preferably, the aldehyde has 1 to 10 carbon atoms. The most preferred aldehyde is formaldehyde.

[0391] Amines suitable for preparing Mannich additives include monoamines and polyamines. One suitable monoamine is butylamine.

[0392] The amine used to prepare the Mannich additive is preferably a polyamine. This can be selected from any compound comprising two or more amine groups. Preferably, the polyamine is a polyalkylene polyamine, preferably a polyethylene polyamine. Most preferably, the polyamine comprises tetraethylenepentamine or ethylenediamine.

[0393] The optionally substituted phenol component used to prepare the Mannich additive may be substituted on the aromatic ring by 0 to 4 groups (in addition to the phenolic OH). For example, it may be a hydrocarbyl-substituted cresol. Most preferably, the phenol component is a monosubstituted phenol. Preferably, it is a hydrocarbyl-substituted phenol. Preferred hydrocarbyl substituents are alkyl substituents having 4 to 28 carbon atoms, especially 10 to 14 carbon atoms. Other preferred hydrocarbyl substituents are polyalkenyl substituents. Such polyisobutylene substituents have a number average molecular weight (Mn) of 400 to 2500, for example 500 to 1500.

[0394] In some embodiments, the diesel fuel composition of the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm of the Mannich additive (ii).

[0395] In some embodiments, the diesel fuel composition further comprises (iii) the reaction product of a carboxylic acid derived acylating agent and an amine.

[0396] These may also be collectively referred to herein as acylated nitrogen-containing compounds.

[0397] Suitable acylated nitrogen compounds can be prepared by reacting a carboxylic acid acylating agent with an amine and are known to those skilled in the art.

[0398] The preferred hydrocarbyl substituted acylating agent is polyisobutenyl succinic anhydride.These compounds are commonly referred to as "PIBSA" and are well known to those skilled in the art.

[0399] Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention.

[0400] Particularly preferred PIBSAs are those having a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 1300.

[0401] In a preferred embodiment, the reaction product of a carboxylic acid derived acylating agent and an amine includes at least one primary or secondary amine group.

[0402] Preferred acylated nitrogen compounds for use herein are prepared by reacting a polyisobutylene-substituted succinic acid-derived acylating agent (e.g., anhydrides, acids, esters, etc.) with a mixture of ethylene polyamines, wherein the polyisobutylene substituent has a number average molecular weight (Mn) of 170 to 2800, and the ethylene polyamines have 2 to about 9 amino nitrogen atoms, preferably about 2 to about 8 nitrogen atoms, and about 1 to about 8 ethylene groups per ethylene polyamine. These acylated nitrogen compounds are suitably formed by reacting an acylating agent: amino compound in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, and most preferably 2:1 to 1:1. In a particularly preferred embodiment, the acylated nitrogen compound is formed by reacting an acylating agent with an amino compound in a molar ratio of 1.8:1 to 1:1.2, preferably 1.6:1 to 1:1.2, more preferably 1.4:1 to 1:1.1, and most preferably 1.2:1 to 1:1. Acylated amino compounds of this type and their preparation are well known to the person skilled in the art and are described, for example, in EP 0 565 285 and US Pat. No. 5,925,151.

[0403] In some preferred embodiments, the composition comprises a cleaning agent of the type formed by the reaction of an acylating agent derived from a polyisobutylene-substituted succinic acid and a polyethylene polyamine. Suitable compounds are described, for example, in WO2009 / 040583.

[0404] In some embodiments, the diesel fuel composition of the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm, of an additive which is the reaction product of an acylating agent and an amine (iii).

[0405] In some embodiments, the diesel fuel composition comprises (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine.

[0406] Suitably, the additive comprises the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine.

[0407] Preferably, the hydrocarbyl group of the hydrocarbyl-substituted succinic acid or anhydride comprises C8-C 36 Group, preferably C8-C 18 Alternatively, the hydrocarbon group may be a polyisobutylene group having a number average molecular weight (Mn) of 200 to 2500, preferably 800 to 1200.

[0408] Hydrazine has the formula NH2-NH2. Hydrazine can be hydrated or non-hydrated. Monohydrated hydrazine is preferred.

[0409] The reaction between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine produces a variety of products, such as disclosed in US 2008 / 0060259.

[0410] In some embodiments, the diesel fuel composition further comprises (v) a salt formed by reacting a carboxylic acid with di-n-butylamine or tri-n-butylamine. Exemplary compounds of this type are described in US 2008 / 0060608.

[0411] Such additives may suitably be of the formula [R'(COOH) X ] y' The di-n-butylamine or tri-n-butylamine salt of a fatty acid, wherein each R' is independently a hydrocarbon group having 2 to 45 carbon atoms, and x is an integer between 1 and 4.

[0412] In a preferred embodiment, the carboxylic acid comprises tall oil fatty acid (TOFA).

[0413] Further preferred features of additives of this type are described in EP1900795.

[0414] In some embodiments, the diesel fuel composition further comprises (vi) a reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt, the product comprising at least one aminotriazole group.

[0415] Further preferred features of additive compounds of this type are as defined in US 2009 / 0282731.

[0416] In some embodiments, the diesel fuel composition further comprises (vii) a substituted polycyclic aromatic detergent additive.

[0417] A preferred compound of this type is the reaction product of ethoxylated naphthol and paraformaldehyde which reaction product is then reacted with a hydrocarbyl-substituted acylating agent.

[0418] Further preferred features of these cleaners are described in EP1884556.

[0419] The present invention reduces the formation of deposits in the after-combustion system of a diesel engine.

[0420] The diesel engine may be a direct injection diesel engine or an indirect injection diesel engine.

[0421] In some embodiments, the engine may be a non-road engine, such as a marine, railroad, or stationary engine. Stationary engines include engines for power generation and engines for pumping.

[0422] Most preferably, the engine is a direct injection diesel engine.

[0423] The post combustion deposit control additives used in the present invention have been found to be particularly effective in modern diesel engines having high pressure fuel systems.

[0424] Suitably, the present invention may be used to reduce the formation of deposits in the afterburning system of a diesel engine having a high pressure fuel system. The fuel pressure of the diesel engine is suitably in excess of 1350 bar (1.35 x 10 8 Pa). Its pressure can be up to 2000 bar (2x10 8 Pa) or higher.

[0425] Such diesel engines can have a variety of features.

[0426] Such engines are typically equipped with fuel injection equipment that meets or exceeds "Euro 5" emissions regulations or equivalent regulations in the United States or other countries.

[0427] Such engines are typically equipped with a fuel injector having a plurality of holes, each hole having an inlet and an outlet.

[0428] Such engines are characterized in that the hole is tapered so that the inlet diameter of the injection hole is larger than the outlet diameter.

[0429] Such modern engines are characterised in that the outlet diameter of the holes is less than 500 μm, preferably less than 200 μm, more preferably less than 150 μm, preferably less than 100 μm, most preferably less than 80 μm or less.

[0430] A characteristic feature of modern diesel engines of this type is that the hole is rounded at the inner edge of the inlet.

[0431] Such modern diesel engines may feature an injector having more than one hole, suitably more than 2 holes, preferably more than 4 holes, for example 6 holes or more.

[0432] Such modern diesel engines may be characterized by operating tip temperatures in excess of 250°C.

[0433] Such modern diesel engines may be characterized in that the fuel injection system provides a fuel pressure greater than 1350 bar, preferably greater than 1500 bar, more preferably greater than 2000 bar.

[0434] Two non-limiting examples of such high pressure fuel systems are: common rail injection systems, in which the fuel is compressed by a high pressure pump to supply it to the fuel injection valves via a common rail; and unit injection systems, which integrate the high pressure pump and the fuel injection valves in one assembly, achieving pressures in excess of 2000 bar (2x10 8 In both systems, as the fuel is pressurized it heats up, typically to temperatures of about 100°C or more.

[0435] Preferably, the diesel engine has a fuel injection system which comprises a common rail injection system.

[0436] In a common rail system, the fuel is stored at high pressure in a central accumulator rail or in separate accumulators before being delivered to the injectors. Typically, some of the heated fuel is returned to the low-pressure side of the fuel system or to the fuel tank. In a unit injection system, the fuel is compressed within the injector to create a high injection pressure. This in turn increases the temperature of the fuel.

[0437] In both systems, the fuel resides within the injector body prior to injection where it is further heated due to the heat of the combustion chamber. The fuel temperature at the injector tip can be as high as 250-350°C.

[0438] Therefore, the pressure of the fuel before injection is 1350 bar (1.35x10 8 Pa) to 2000 bar (2x10 8 Pa) and temperatures of about 100°C to 350°C are sometimes recirculated back into the fuel system, increasing the time the fuel experiences these conditions.

[0439] Aftercombustion systems for diesel engines are provided in order to reduce the emission of pollutants such as particulate matter and noxious gases into the environment. The formation of deposits on aftercombustion system components can reduce the efficiency of the system and lead to increased emissions of particulate deposits and / or noxious gases.

[0440] In some embodiments, the effects of the deposits may be reduced by changing the properties of the deposits.

[0441] Preferably, the present invention reduces the formation of deposits in the post-combustion system.

[0442] Reducing the formation of deposits in a post combustion system means that when a fuel comprising a post combustion deposit reducing additive is combusted in an engine, reduced deposit levels are obtained compared to combusting an otherwise identical fuel except for the inclusion of the post combustion deposit reducing additive under the same conditions.

[0443] Suitably adding the nitrogen-containing compounds of the invention to diesel fuel combusted in an engine may reduce deposit formation in one or more components of the afterburner system by at least 0.01%, preferably at least 0.1%, for example at least 1% or at least 2%.

[0444] In some embodiments, adding a nitrogen-containing compound to a diesel fuel combusted in an engine can reduce the formation of deposits in one or more components of the post-combustion system by at least 3%, such as at least 4% or at least 5%.

[0445] The aftercombustion system of a diesel engine refers to any part of the engine through which the exhaust gases pass after they finally leave the combustion system. An exhaust gas recirculation (EGR) system is not considered part of the aftercombustion system within the meaning of this invention, as gases passing through the EGR system may enter the combustion chamber.

[0446] The afterburning system may include one or more components selected from a turbocharger, a diesel oxidation catalyst, a diesel particulate filter, a selective catalytic reduction unit, and an ammonia oxidation unit. The afterburning system may include these components in any order, and the order may vary from vehicle to vehicle. The present invention may reduce the effects of deposits in or on one or more of these components.

[0447] In some embodiments, the addition of nitrogen-containing compounds to diesel fuel combusted in an engine may suitably reduce deposit formation in a turbocharger by at least 0.01%, preferably at least 0.1%, such as at least 1% or at least 2%.

[0448] The present invention can reduce deposits on fixed geometry turbochargers or variable geometry turbochargers. Variable geometry turbochargers have moving parts that are controlled by the engine management system. This allows the aspect ratio of the turbocharger to be changed to optimize performance at different speeds. The formation of deposits can cause the components to stick. As a result, the turbocharger will not be able to provide the correct level of boost and may eventually fail. Therefore, reducing deposits on the turbocharger is very beneficial.

[0449] Preferably, the present invention reduces deposits on a turbine wheel of a turbocharger.

[0450] In some embodiments, adding a nitrogen-containing compound to a diesel fuel combusted in an engine can reduce the formation of deposits in a turbocharger by at least 3%, such as at least 4% or at least 5%.

[0451] In some embodiments, the addition of nitrogen containing compounds to diesel fuel combusted in an engine may suitably reduce deposit formation in a diesel oxidation catalyst by at least 0.01%, preferably at least 0.1%, such as at least 1% or at least 2%.

[0452] Diesel oxidation catalysts typically include a ceramic support structure coated with a metal such as palladium, platinum and / or rhodium. The formation of deposits in a diesel oxidation catalyst can result in reduced flow through the catalyst and / or poisoning of the catalyst.

[0453] In some embodiments, adding a nitrogen-containing compound to a diesel fuel combusted in an engine can reduce the formation of deposits in a diesel oxidation catalyst by at least 3%, such as at least 4% or at least 5%.

[0454] Suitably the addition of the nitrogen containing compound to the diesel fuel combusted in the engine may reduce the formation of deposits in the diesel particulate filter by at least 0.01%, preferably at least 0.1%, for example at least 1% or at least 2%.

[0455] Suitably the addition of a nitrogen containing compound to diesel combusted in an engine may reduce soot accumulation in a diesel particulate filter, suitably by at least 0.01%, preferably by at least 0.1%, for example by at least 1% or at least 2%.

[0456] Diesel particulate filters are designed to capture particles such as soot formed in the combustion chamber from the exhaust gases. These particles collect on the filter and are intermittently burned off by raising the exhaust gas temperature and injecting additional fuel. This process is called filter regeneration.

[0457] The use of the first aspect and / or the method of the second aspect may involve using one or more nitrogen-containing compounds as an additive in the diesel fuel composition to reduce the formation of deposits in a diesel particulate filter of the diesel engine.

[0458] In some embodiments, the use of the first aspect and / or the method of the second aspect involves using one or more nitrogen-containing compounds as an additive in the diesel fuel composition to reduce the formation of deposits in the diesel particulate filter of the diesel engine; wherein the one or more nitrogen-containing compounds are selected from one or more of the following:

[0459] A) The reaction product of:

[0460] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0461]

[0462] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0463] b) a nitrogen-containing reagent selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole;

[0464] B) The reaction product of:

[0465] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0466]

[0467] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0468] b) a nitrogen-containing reagent having the formula (bI):

[0469]

[0470] wherein n is from 1 to 10; and

[0471] C) the reaction product of:

[0472] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0473] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and

[0474] c) Formaldehyde or a formaldehyde source.

[0475] Suitably, the use or method reduces the accumulation of soot in a diesel particulate filter.

[0476] In some preferred embodiments, the use of the first aspect and / or the method of the second aspect comprises using one or more nitrogen-containing compounds as additives in the diesel fuel composition to reduce the formation of deposits in the diesel particulate filter of the diesel engine; wherein the one or more nitrogen-containing compounds are selected from one or more of the following:

[0477] A) The reaction product of:

[0478] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0479]

[0480] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0481] b) a nitrogen-containing reagent selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole

[0482] and

[0483] C) the reaction product of:

[0484] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0485] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and

[0486] c) Formaldehyde or a formaldehyde source.

[0487] Suitably, the use or method reduces the accumulation of soot in a diesel particulate filter.

[0488] In some preferred embodiments, the use of the first aspect and / or the method of the second aspect involves using one or more nitrogen-containing compounds as additives in the diesel fuel composition to reduce the formation of deposits in the diesel particulate filter of the diesel engine; wherein the one or more nitrogen-containing compounds are selected from one or more of the following:

[0489] A) The reaction product of:

[0490] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0491]

[0492] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0493] b) a nitrogen-containing reagent selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole.

[0494] Suitably, the use or method reduces the accumulation of soot in a diesel particulate filter.

[0495] In some preferred embodiments, the use of the first aspect and / or the method of the second aspect involves using one or more nitrogen-containing compounds as additives in the diesel fuel composition to reduce the formation of deposits in the diesel particulate filter of the diesel engine; wherein the one or more nitrogen-containing compounds are selected from one or more of the following:

[0496] B) The reaction product of:

[0497] a) a hydrocarbyl-substituted carboxylic acylating agent having the formula (aI):

[0498]

[0499] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0500] b) a nitrogen-containing reagent having the formula (bI):

[0501]

[0502] wherein n is from 1 to 10; and

[0503] Suitably, the use or method reduces the accumulation of soot in a diesel particulate filter.

[0504] In some preferred embodiments, the use of the first aspect and / or the method of the second aspect involves using one or more nitrogen-containing compounds as additives in the diesel fuel composition to reduce the formation of deposits in the diesel particulate filter of the diesel engine; wherein the one or more nitrogen-containing compounds are selected from one or more of the following:

[0505] C) the reaction product of:

[0506] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0507] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and

[0508] c) Formaldehyde or a formaldehyde source.

[0509] Suitably, the use or method reduces the accumulation of soot in a diesel particulate filter.

[0510] The present invention can increase the interval between regenerations. This can improve the fuel economy of the engine and reduce emissions. By reducing regeneration we mean reducing active, passive or parked regeneration of the diesel particulate filter. For example, the number of regeneration events per 1000 kilometers can be reduced.

[0511] In some embodiments, adding nitrogen-containing compounds to diesel fuel combusted in an engine can reduce the formation of deposits in a diesel particulate filter by at least 3%, such as at least 4% or at least 5%.

[0512] In some embodiments, adding nitrogen containing compounds to diesel fuel combusted in an engine may suitably reduce deposit formation in the selective catalytic reduction unit by at least 0.01%, preferably at least 0.1%, such as at least 1% or at least 2%.

[0513] Selective catalytic reduction for removal of NO from exhaust gas streams xand other harmful gases, and involves the use of ammonia as a reducing agent in the presence of a catalyst. The selective catalytic reduction unit comprises a porous ceramic support and a catalyst, typically comprising a metal or a zeolite.

[0514] The formation of deposits on the selective catalytic reduction unit may result in reduced flow rate through the unit and / or poisoning of the catalyst.

[0515] In some embodiments, adding nitrogen-containing compounds to diesel fuel combusted in an engine can reduce the formation of deposits in the selective catalytic reduction unit by at least 3%, such as at least 4% or at least 5%.

[0516] In some embodiments, the addition of nitrogen containing compounds to diesel fuel combusted in an engine may suitably reduce the formation of deposits in the ammonia oxidation catalyst by at least 0.01%, preferably at least 0.1%, such as at least 1% or at least 2%.

[0517] The ammonia oxidation catalyst is used to oxidize any ammonia present in the exhaust gas after passing through the selective catalytic reduction unit.

[0518] The formation of deposits on the ammonia oxidation catalyst may result in reduced flow rate through the catalyst and / or poisoning of the catalyst.

[0519] In some embodiments, adding a nitrogen-containing compound to a diesel fuel combusted in an engine can reduce the formation of deposits in an ammonia oxidation catalyst by at least 3%, such as at least 4% or at least 5%.

[0520] In some embodiments, adding nitrogen containing compounds to diesel fuel combusted in an engine may suitably reduce the formation of deposits on sensors within the post combustion system by at least 0.01%, preferably at least 0.1%, such as at least 1% or at least 2%.

[0521] Sensors can be located in the post-combustion to measure temperature, pressure and / or gases in the exhaust such as NO x If deposits are present on or around the sensors, they may not function properly or may make inaccurate measurements, resulting in incorrect information being provided to the engine management system. This can result in poor engine performance.

[0522] In some embodiments, adding nitrogen-containing compounds to diesel fuel combusted in an engine can reduce the formation of deposits on sensors within a post-combustion system by at least 3%, such as at least 4% or at least 5%.

[0523] The reduction of deposits in the post-combustion system may be measured by any suitable method.

[0524] A simple method of determining the level of deposits in a component of an afterburner system may be by weighing that component of the system before and after use. One or more components of the system may be weighed.

[0525] Other less direct methods may also be used. For example, improved fuel economy may indicate longer intervals between regenerations of a diesel particulate filter. By improved fuel economy, it is meant that when a fuel comprising a post-combustion deposit reduction additive is combusted in an engine, improved fuel economy is achieved compared to combusting an otherwise identical fuel under the same conditions except for the inclusion of the post-combustion deposit reduction additive.

[0526] Preferably the invention provides an improvement in fuel economy of at least 0.1%, preferably at least 0.5%, suitably at least 1%, for example at least 2%.

[0527] The vehicle's engine management system can be queried to evaluate the performance of components such as the turbocharger, diesel particulate filter, diesel oxidation catalyst and selective catalytic reduction unit.

[0528] The invention may result in fewer error messages being provided to the driver by the engine management system.

[0529] Increased maintenance intervals required for catalytic components may also indicate improved performance due to reduced deposits.

[0530] The deposits formed in the post-combustion system can be analyzed. This can be achieved, for example, by extracting the deposits or a portion thereof into a solvent. The sample can be separated into soluble and insoluble fractions; these fractions can then be analyzed separately by methods known to those skilled in the art, such as elemental analysis, thermogravimetric analysis and / or gas chromatography mass spectrometry.

[0531] Thermogravimetric analysis (or TGA) involves measuring the mass of a sample over time during heating. The technique is well known to those skilled in the art, and the selection of an appropriate method and suitable equipment will be within the capabilities of those skilled in the art.

[0532] When the post-composite deposit contains soot, the soot density can be measured, for example using the AVL483 micro-soot sensor.

[0533] The particle size of the soot can be measured by techniques known to those skilled in the art.

[0534] Reducing deposits in the aftercombustion system of a diesel engine in accordance with the present invention has significant benefits.

[0535] These include, but are not limited to: increased power generation; increased torque; improved fuel economy; reduced emissions; reduced combustion chamber deposits; improved acceleration; improved drivability; reduced cold start issues; reduced soot formation; reduced lubricant degradation and / or performance loss; reduced diesel exhaust fluid and consumption, such as urea consumption; reduced wear of all aftercombustion components (including but not limited to turbochargers, oxidation catalysts, DPFs, SCR CATs, sensors and injectors within the aftercombustion system); increased service life of exhaust components; extended maintenance intervals for the engine and / or aftercombustion components; and protection of intake components downstream of the EGR, such as swirl flaps, throttle bodies and intake manifolds (due to reduced likelihood of clogging, etc.).

[0536] Any feature of the invention may be combined with any other feature as appropriate. Example

[0537] An example of a nitrogen-containing compound useful as an additive in a diesel fuel composition according to the present invention is prepared as follows.

[0538] Example 1 - PIB 260 SA 5-Amino-[1H]-tetrazolyl reaction products

[0539] Main components:

[0540]

[0541] The nitrogen-containing compound of Example 1 was prepared as follows. A highly reactive grade of 260 number average high reactive (HR) polyisobutylene (PIB 260 ) and maleic anhydride (MA) to obtain polyisobutylene succinic anhydride (PIB 260 SA) sample. PIB 260 SA was partially characterized by titration with lithium methoxide and its activity was found to be 2.38 mmol.g -1 .

[0542] PIB 260 SA sample (135.01 g, 321.3 mmol) and Caromax20 solvent (162.3 g) were charged into the reactor and heated to 90° C. 5-amino-[1H]-tetrazole monohydrate (33.10 g, 321.1 mmol) was added, and the contents of the flask were heated to above 100° C. for one hour. Subsequently, the temperature was raised to reach an internal temperature of 170° C., thereby promoting the formation of amides. ATR-FTIR was used to monitor the progress of the reaction.

[0543] The nitrogen content of three essentially identically prepared samples was analyzed using a Leco Flash 1112 series analyzer and found to range from 6.45 to 6.53 wt %. The theoretical nitrogen content of the target compound is 15.1 to 17.2 wt %.

[0544] Example 2-C 16 / C 18 ASA 5-amino-[1H]-tetrazolyl reaction product

[0545] Main components:

[0546]

[0547] Where R 3 The sum of the groups is C 13 H 28 or C 15 H 32 or a mixture thereof.

[0548] The nitrogen-containing compound of Example 2 was prepared as follows. The activity of a Pentasize 68 sample (commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.g -1 16.86 g (50 mmol active) of the highly aromatic solvent Innosol PP (20.256 g) was charged to the reaction flask. 5-Amino-[1H]-tetrazole monohydrate (5.164 g 50 mmol) was added and stirred to form a dispersion.

[0549] The dispersion was heated to a final internal temperature of 170° C. using a thermostatically controlled oil bath. The progress of the reaction was monitored intermittently using ATR-FTIR spectroscopy. The product contained approximately 50% by weight of the C16 / C18 ASA 5-amino-[1H]-tetrazole reaction product. The theoretical nitrogen content of the target compound was 16.1 to 17.8% by weight.

[0550] Example 3 - Imides from the reaction of C16 / C18 ASA with tetraethylenepentamine (TEPA)

[0551] Main components:

[0552]

[0553] Where R 3 The sum of the groups is C 13 H 28 or C 15 H 32 or a mixture thereof.

[0554] The nitrogen-containing compound of Example 3 was prepared as follows. The activity of a Pentasize 68 sample (commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.g -1 . To the reaction flask was added 150.02 g (446 mmol active) of Pentasize 68 and 2-ethylhexan-1-ol solvent (234.09 g). TEPA (84.40 gg, 446 mmol, 1.0 mole per anhydride group) was charged to the pressure-equalized dropping funnel. The contents of the flask were warmed in an oil bath controlled by a thermostat set at 70°C. The oil bath set point was raised to 175°C and the reactor contents were allowed to warm.

[0555] The progress of the reaction was monitored intermittently using ATR-FTIR spectroscopy. The product contained 49.88 wt % of the imide product. The theoretical nitrogen content of the target compound was 13.0 to 13.7 wt %.

[0556] Example 4 - Mannich Reaction Products of Diethylamine, Formaldehyde and Benzotriazole

[0557] Main components:

[0558]

[0559] The nitrogen-containing compound of Example 4 was prepared as follows. Diethylamine (21.945 g, 301 mmol) was added to methanol (100 cm3) according to the method of Katritzky et al. J Chem Soc Perkin Trans 1987, 2673. The mixture was cooled back to 3°C and 1H-benzotriazole (35.739 g, 301 mmol) was added. Aqueous formaldehyde (nominal 37 wt%, 24.324 g, 300 mmol, 1.0 equiv) was added to the reactor over 10 minutes and the reaction mixture was stirred for 50 minutes and then allowed to warm to ambient temperature while stirring overnight. The methanol was removed on a rotary evaporator and 58.441 g (expected 61.33) of a slightly viscous yellow oil was recovered.

[0560] The obtained product was confirmed by comparing the ATR-FTIR spectrum with the literature. 1 H NMR was consistent with the Katritzky reference, but indicated a 1-isomer to 2-isomer ratio of 3.71. The product was found to contain 62.24 wt% C, 7.55 wt% H, and 27.09 wt% N using a Thermoflash elemental analyzer. The theoretical nitrogen content of the target compound was 27.4 wt%.

[0561] A 63.5% by weight solution of the target compound in 2-ethylhexanol gives a clean and bright diesel fuel solution with an active substance content of up to 5% by weight.

[0562] Example 5 - Two-phase Mannich reaction product of diethylamine, formaldehyde and benzotriazole Main components:

[0563]

[0564] Benzotriazole powder (60.0 g, 0.504 mol) and solvent 150 (102.8 g) were loaded into a reaction flask. The slurry was heated to 30 ° C, and then diethylamine (15.1 g) was added. Then, formaldehyde solution (36.8 g 37 wt % formaldehyde solution) was added over a period of 25 minutes, maintaining the temperature at 40-47 ° C. After stirring for two hours at 40 ° C, the reactor contained two liquid phases, which were transferred to a separatory funnel after being heated to 70 ° C. The recovered aqueous phase contained 27.4 g of material. Additional water and some organic matter were removed by vacuum distillation at 70 ° C, 25 mBar, leaving a transparent organic solution.

[0565] The product structure was confirmed by FTIR. The theoretical N content of the product was 13.7 wt%.

[0566] Example 6 - Two-phase Mannich reaction product of benzotriazole, formaldehyde and bis(2-ethylhexyl)amine

[0567] Main components:

[0568]

[0569] The nitrogen-containing compound of Example 6 was prepared as follows. Benzotriazole powder (50.1 g, 0.421 mole) and 157 g Solvent 150 were charged to a reaction flask. The slurry was warmed to about 30° C. and then bis(2-ethylhexyl)amine (101.7 g) was added over 20 minutes, followed by 34.1 g of a 37 wt % active formaldehyde solution.

[0570] The reaction mixture was heated to 80°C and transferred to a separatory funnel and the organic layer was separated. Water was distilled off from the separated organic layer to obtain a clear organic phase whose FTIR spectrum was similar to that of the product of Example 5.

[0571] The theoretical nitrogen content of the target compound is 15.0% by weight.

[0572] Example 7 - Two-phase Mannich reaction product of 1,2,4-triazole, formaldehyde and di-n-butylamine

[0573] Main components:

[0574]

[0575] The nitrogen-containing compound of Example 7 was prepared as follows: 1,2,4-triazole (40.4 g, 0.585 mole) and 133.6 g of Solvent 150 were added to a reaction flask, followed by di-n-butylamine (75.6 g). After further heating (39° C.), the addition of aqueous formaldehyde (47.4 g, 37 wt % solution) was started.

[0576] The organic layer was separated from the reaction mixture and dried by vacuum distillation to produce 249.6 g of a product solution. The theoretical N content of the product mixture (including solvent) was 13.3 wt %, and the concentrate was analyzed to contain 13.0 wt % N, 60.8 wt % C, and 8.7 wt % H.

[0577] The theoretical nitrogen content of the target compound is 26.6% by weight.

[0578] Example 8: Benzotriazole-formaldehyde-dibutylamine

[0579] Main components:

[0580]

[0581] In a 500 ml round bottom flask, benzotriazole (60.1 g, 0.505 mole, 1.0 equivalent) and A150 solvent (131.5 g) were added and heated to 30°C to form a white slurry. Dibutylamine (65.3 g, 1 equivalent, 0.505 mole) was added via a dropping funnel over 25 minutes. The mixture was heated to 31°C in a flask and formalin (37% w / w, 41.0 g, 0.505 mole, 1.0 equivalent) was started and carried out over a period of 15-20 minutes. A milky white liquid was formed immediately after the addition and the contents separated into two phases. The temperature of the reactor contents was then adjusted to 45-50°C and maintained at that temperature for 5 hours. The reaction mixture was allowed to cool overnight. To separate the reaction mixture, it was heated to 70°C. The separation was clear and the lower, now turbid, aqueous layer had flowed out. 30.9 g was collected, and the theoretical water content in the reaction was 34.9 g. The organic phase was heated to 75° C. and a vacuum of about 20 mbar was applied. 254.9 g of a clear, bright yellow liquid were isolated (about 50% active substance solution).

[0582] The theoretical nitrogen content of the target compound is 21.5% by weight.

[0583] Example 9: Benzotriazole-formaldehyde-Armeen 2C (dicocoyl alkylamine)

[0584] Main components:

[0585]

[0586] In a 500 ml round bottom flask, benzotriazole (26.0 g, 0.218 mole, 1.0 equiv) and A150 solvent (116.0 g) were added and heated to 90°C. Armeen 2C (87.4 g, 0.218 mole, 1 equiv [equivalent weight 401 g / mol]) (mixture of dicocoalkylamines where cocoalkyl = C6-18 alkyl) was added to the flask. Formalin (37% w / w, 0.218 mole, 1.0 equiv) was then added over 5 minutes and the reaction mixture was stirred at 90°C for 2.5 hours. The temperature in the reaction flask was raised to 119°C over 3 hours and water was removed by a Dean and Stark trap. When no more aqueous phase was collected and the product was clear and bright, the temperature was cooled to ambient temperature. 222.5 g of a clear, bright amber liquid (50% active substance solution) was collected.

[0587] Example 10: 1,2,4-Triazole-formaldehyde-bis(2-ethylhexyl)amine

[0588] Main components:

[0589]

[0590] Formalin (159.6 g, 26.6% active formaldehyde, 1.9447 mol, 0.995 eq) and 1,2,4-triazole (156.0 g, 1.9545 mol, 1.0 eq) were added and heated to 60°C. Bis-(2-ethylhexyl)amine (462.5 g, 1.9154 mol, 0.98 eq) was added to the water mixture at 60°C over 2.5 hours and the material was stirred for 1 hour to complete the reaction. The water and reaction water in the formalin solution were removed by vacuum distillation at 60-100°C (100-200 mbar). After water removal, the remaining volatiles and traces of water were removed by stripping under increasing vacuum and the product (615.4 g) was discharged as a pale yellow liquid through a filter.

[0591] The theoretical nitrogen content of the target compound is 17.4% by weight.

[0592] Engine testing

[0593] Engine testing was performed as described below to evaluate the performance of the nitrogen-containing additives of the present invention in reducing deposits in the aftercombustion system of a diesel engine.

[0594] Engine Details

[0595] A 2.0-liter HSDI engine that complies with the Euro 6 standard is connected to a test automation system and test bench equipped with an engine dynamometer. The engine is controlled by an ECU provided by the engine manufacturer. Before the first test, the engine had been used for more than 1,100 hours. Before the first test, the engine oil was changed.

[0596] Improve / Test Settings

[0597] 1. There is no SCR catalyst or related components in the exhaust system.

[0598] 2. The high pressure EGR cooler was artificially controlled at 40°C during the test.

[0599] The base fuel was RF-06-03 diesel fuel (Haltermann Carless, UK) with the following specifications:

[0600]

[0601] Test additives, treatment rate:

[0602] The nitrogen-containing compound of Example 9 was added to the base fuel to provide Test Fuel A at a dosage of 100 mg / kg.

[0603] Soot Deposition Measurement Method (DPF and EGR Soot Weight)

[0604] The amount of soot deposited in the DPF was determined by weighing both assemblies before and after each test.

[0605] Prior to the initial weighing, the DPF was passively regenerated on a test bench to remove any residual soot. Once regeneration was complete, the DPF was placed in an oven, preheated to 185°C, and mounted on a set of scales. After the scales had stabilized, the weight measurements were averaged over a 15-minute period. This weighing process was repeated at the end of the test. The difference between the weights measured before and after the test represents the change in mass due to soot deposition.

[0606] Testing Procedure

[0607] -[D] EGR cleaning and weighing

[0608] -[D]DPF+Slave EGR Installation

[0609] -Engine start + warm up

[0610] - Passive DPF regeneration is performed by varying engine speed and load until regeneration is complete. The differential pressure across the DPF is used to monitor the progress of regeneration.

[0611] - Engine stop

[0612] -Change the test fuel

[0613] -[C]DPF+slave EGR removed

[0614] -[C]DPF Start of Test (SOT) weighing

[0615] -[C]DPF+[C]EGR installation

[0616] -Engine start + warm up

[0617] -8 hours steady state test cycle

[0618] -1200RPM

[0619] -60Nm

[0620] - Engine stop

[0621] - [D]DPF removal and end-of-test (EOT) weighing

[0622] -[D] EGR removal and EGR test end weighing

[0623] [C] indicates a clean component

[0624] [D] indicates fouling component

[0625] result

[0626]

[0627] These results demonstrate that the use of the nitrogen-containing compounds described herein as additives in diesel fuel compositions can significantly reduce deposits in the aftercombustion system of a diesel engine combusting said fuel, and in particular reduce soot deposited on a diesel particulate filter of the aftercombustion system.

Claims

1. Use of one or more nitrogen-containing compounds as an additive in a diesel fuel composition to reduce the effect of deposits in the after-combustion system of a diesel engine when the diesel fuel composition is combusted, wherein the nitrogen-containing compound comprises at least 4% by mass of nitrogen atoms.

2. A method of reducing the effects of deposits in an after-combustion system of a diesel engine, the method comprising burning in the engine a diesel fuel composition comprising one or more nitrogen-containing compounds as additives, wherein the nitrogen-containing compounds comprise at least 4 mass % nitrogen atoms.

3. Use or method according to claim 1 or claim 2, which reduces the formation of deposits in the aftercombustion system of a diesel engine.

4. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound is the reaction product of a) a hydrocarbyl substitution agent and b) a nitrogen-containing agent.

5. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound has formula (I): A-L-R 1 (I) in: A is a nitrogen-containing group; L is a bond or a linking group; and R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

6. The use or method according to claim 5, wherein the nitrogen-containing group A is a nitrogen-containing heterocycle and is selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocycle such as pyrazole or imidazole or a benzo-fused five-membered heterocycle such as benzimidazole.

7. The use or method according to claim 5, wherein the A group is an acyclic nitrogen-containing group having formula (II): Wherein n is 1 to 10.

8. The use or method of any one of claims 5 to 7, wherein L is a bond, an amide, a succinimide, succinic acid or an amide of succinic acid.

9. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound is the reaction product of: a) a hydrocarbyl-substituted carboxylic acylating agent; and b) Nitrogen-containing reagents.

10. The use or method according to claim 9, wherein component a) has formula (al): Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

11. The use or method according to claim 9 or 10, wherein component b) is: is selected from optionally substituted benzotriazole, aminobenzotriazole, indazole, aminoindazole, triazole, aminotriazole, tetrazole or aminotetrazole; or Having formula (bI): Wherein n is 1 to 10.

12. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound has the formula (III): in: A is a nitrogen-containing group; R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and R 2 OH, NH2, OR 4 、NHR 4 or NR 4 R 5 , where R 4 and R 5 is independently selected from optionally substituted C1-6 alkyl or alkenyl, or is a bond to A.

13. The use or method of claim 12, wherein the nitrogen-containing compound has formula (IV), (IVb) or (IVc), or a mixture thereof: Where R 1 and R 2 As defined in claim 12.

14. The use or method of claim 12, wherein the nitrogen-containing compound has formula (V): wherein n is 1 to 3, or a mixture thereof; and Where R 1 As defined in claim 12.

15. The use or method according to any one of claims 1 to 6, wherein the nitrogen-containing compound is the reaction product of: a) amines or polyamines containing hydrocarbon groups; b) nitrogen-containing reagents; and c) Aldehydes.

16. The use or method according to claim 15, wherein: a) is a product having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl; b) is a nitrogen-containing reagent selected from optionally substituted triazole, tetrazole, indole, indazole or benzotriazole, and c) is formaldehyde or a formaldehyde source.

17. The use or method according to any one of claims 1 to 6, 15 or 16, wherein the nitrogen-containing compound has formula (VI): in: R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and The compound optionally comprises a cycloalkyl or aromatic ring connecting Y and Z.

18. The use or method of claim 17, wherein the nitrogen-containing compound has formula (IX): in: R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; W and X are each independently selected from C and N; and Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

19. The use or method according to claim 18, wherein R 1 CH2NR 7 R 8 And R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl.

20. The use or method of any preceding claim, wherein the nitrogen-containing compound comprises less than five NH bonds.

21. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises from 50 to 2000 ppm of one or more nitrogen containing compounds.

22. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises from 50 to 350 ppm of one or more nitrogen containing compounds.

23. Use or method according to any one of the preceding claims to reduce deposits in the after combustion system of a diesel engine at pressures exceeding 1350 bar.

24. Use or method according to any one of the preceding claims, which reduces the formation of deposits on a turbocharger of a post-combustion system.

25. Use or method according to any one of the preceding claims, which reduces the formation of deposits on a diesel oxidation catalyst of a post-combustion system.

26. Use or method according to any one of the preceding claims, which reduces the formation of deposits on a diesel particle filter of a post-combustion system.

27. Use or method according to any one of the preceding claims, which reduces the formation of deposits on a selective catalytic reduction unit of a post-combustion system.

28. Use or method according to any one of the preceding claims, which reduces the formation of deposits on an ammonia oxidation catalyst of a post-combustion system.

29. Use or method according to any one of the preceding claims to reduce the formation of deposits on sensors in a post combustion system.

30. Use or method according to any preceding claim, which reduces the formation of deposits in one or more components of a post-combustion system by at least 5%.

31. Use or method according to any one of the preceding claims, which allows reducing the temperature of the exhaust gases for regenerating a diesel particle filter of a post-combustion system.

32. Use or method according to any one of the preceding claims, which allows reducing the frequency of diesel particulate filter regeneration in the diesel engine.

33. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises one or more nitrogen-containing detergents.

34. The use or method of claim 33, wherein the one or more nitrogen-containing cleaning agents are selected from: (i) quaternary ammonium salt additives; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

35. Use or method according to any preceding claim, wherein the diesel engine is a non-road engine, such as a marine, railway or stationary engine.

36. The use or method of any of the preceding claims, providing one or more benefits selected from the group consisting of: increased power generation; increased torque; improved fuel economy; reduced emissions; reduced combustion chamber deposits; improved acceleration; improved drivability; reduced cold start issues; reduced soot formation; reduced lubricant degradation and / or performance loss; reduced diesel exhaust fluid and consumption, such as urea consumption; reduced wear of all after-combustion components; increased service life of exhaust components; extended maintenance intervals for the engine and / or after-combustion components; and protection of intake components downstream of the EGR, such as swirl flaps, throttle valves and intake manifolds.

37. A fuel additive composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compounds contain at least 4 mass % nitrogen atoms.

38. A diesel fuel composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compounds comprise at least 4 mass % nitrogen atoms.

39. A diesel fuel composition according to claim 38 comprising one or more additional additives selected from the group consisting of antioxidants, dispersants, detergents, metal deactivation compounds, wax anti-settling agents, cold flow improvers, cetane number improvers, demisters, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal deactivators, odor masking agents, drag reducers and conductivity improvers.

40. The fuel additive composition of claim 37 or the diesel fuel composition of claim 38 or claim 39, wherein the detergent additive is: The reaction product of a carboxylic acid-derived acylating agent and an amine, the detergent additive being the reaction product of tetraethylenepentamine (TEPA) and PIBSA, wherein the PIBSA has a PIB number average molecular weight (Mn) of 300 to 2800; or A quaternary ammonium salt formed by the reaction of methyl salicylate or dimethyl oxalate with the reaction product of dimethylaminopropylamine and polyisobutylene-substituted succinic anhydride, wherein the polyisobutylene-substituted succinic anhydride has a PIB number average molecular weight (Mn) of 700 to 1300.

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