Fuel compositions comprising additives and related methods and uses thereof

Abstract

A fuel composition comprising as an additive a polymer of formula (I): # imgabs0 # wherein n is at least 4, x may be 0 or a positive integer, y may be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, with the proviso that at least 10% of all R groups are not hydrogen.

Description

[0001] The present invention relates to methods and uses of additives to improve the performance of fuel compositions. The present invention relates to diesel fuel and gasoline fuel compositions suitable for use in modern engines where the fuel injectors are exposed to high temperatures and high pressures. In particular, the present invention relates to additives for diesel fuel compositions, especially additives for diesel engines having high pressure fuel systems.

[0002] Diesel engines have become more fuel efficient, with improved performance and reduced emissions in recent years, due to consumer demand and legislation.

[0003] These improvements in performance and emissions are brought about by improvements in the combustion process. In order to achieve the fuel atomization necessary for this improved combustion, fuel injection equipment has been developed that uses higher injection pressures and reduced fuel injector nozzle hole diameters. Fuel pressures at the nozzle now typically exceed 1500 bar (1.5x10 8 Pa). The work that must be done on the fuel to achieve these pressures also increases the temperature of the fuel. These high pressures and temperatures can cause fuel degradation. Additionally, the timing, quantity, and control of fuel injection are becoming increasingly precise. This precise fuel metering must be maintained to achieve optimal performance.

[0004] Diesel engines with high pressure fuel systems may include, but are not limited to, heavy duty diesel engines and smaller passenger car diesel engines. Heavy duty diesel engines may include very powerful engines such as the MTU Series 4000 diesel, which has a 20 cylinder variant and is designed primarily for marine and power generation, with a power output of up to 4300 kW, or engines such as the Renault dXi 7, which has 6 cylinders and a power output of approximately 240 kW. A typical passenger car diesel engine is the Peugeot DW10, which has 4 cylinders and a power output of 100 kW or less, depending on the variant.

[0005] A common problem with diesel engines is injector (particularly injector bodies) and injector nozzle fouling. Fouling can also occur in fuel filters. Injector nozzle fouling occurs when the nozzle becomes clogged with deposits in the diesel fuel. Fuel filter fouling can be associated with the recirculation of fuel back into the fuel tank. Deposits increase as the fuel deteriorates. Deposits can be in the form of carbonaceous coke-like residues, varnish, or sticky or gummy residues. The more diesel fuel is heated, especially under pressure, the more unstable it becomes. Therefore, diesel engines with high-pressure fuel systems may experience increased fuel degradation. In recent years, the need to reduce emissions has led to the continuous redesign of injection systems to help meet lower targets. This has led to injectors that are increasingly complex and less tolerant of deposits.

[0006] Injector fouling can occur when using any type of diesel fuel. However, certain fuels may be more susceptible to fouling or may occur more quickly when using these fuels. For example, fuels containing biodiesel and fuels containing metallic species may cause increased deposits.

[0007] When an injector becomes clogged or partially clogged, fuel delivery becomes less efficient and the fuel-air mixture becomes poorer. Over time, this can lead to a loss of engine power, increased exhaust emissions and reduced fuel economy.

[0008] Deposits are known to occur in the spray passages of injectors, resulting in reduced flow and power losses. As the size of the injector nozzle orifice decreases, the relative impact of deposit buildup becomes more significant. Deposits are also known to occur at the injector tip. Here they affect the fuel spray pattern and result in reduced combustion efficiency, and associated increased emissions and increased fuel consumption.

[0009] In addition to these "external" injector deposits in the nozzle bore and at the injector tip causing reduced flow and power loss, deposits can also occur within the injector body causing further problems. These deposits may be referred to as internal diesel injector deposits (or IDIDs). IDIDs appear on critical moving parts further up inside the injector. They can impede the movement of these parts, affecting the timing and amount of fuel injected. Since modern diesel engines operate under very precise conditions, these deposits can have a significant impact on performance.

[0010] IDID can cause a number of problems, including a loss of power and reduced fuel economy due to less than ideal fuel metering and combustion. Initially, the engine may experience cold start problems and / or a rough running engine. These deposits can lead to more serious injector sticking. This occurs when the deposits prevent the injector parts from moving and therefore the injector stops working. When several or all injectors stick, the engine may fail completely.

[0011] Industry insiders consider IDID to be a serious problem and the industry group European Coordination Committee (CEC) has developed a new engine test. The IDID DW10C test was developed to be able to differentiate between fuels that do not produce measurable deposits and fuels that produce deposits that cause unacceptable starting performance issues. The purpose of this test is to differentiate between fuels that differ in their ability to produce IDID in a direct injection common rail diesel engine.

[0012] Diesel injector internal deposits are known to contain a variety of components. In addition to carbonaceous deposits, the presence of varnish and / or carboxylate residues can also lead to injector sticking.

[0013] Lacquer is a varnish-like deposit that is insoluble in fuel and common organic solvents. Some lacquers that occur have been found to contain amide functional groups, and it has been proposed that they are formed due to the presence of low molecular weight amide-containing species in the fuel.

[0014] Carboxylate residues may come from a variety of sources. Carboxylate residues refer to salts of carboxylic acids. These may be short-chain carboxylic acids, but more commonly, long-chain fatty acid residues are present. Carboxylic acid residues may be present in the form of ammonium salts and / or metal salts. Carboxylic acids and metals from a variety of sources may coexist in diesel fuel. Carboxylic acids may be produced as a result of oxidation of the fuel, may be formed during the combustion process; and are often added to fuels as lubricity additives and / or corrosion inhibitors. Residual fatty acids may be present in the fatty acid methyl esters contained in biodiesel; and they may also be present as by-products in other additives. Derivatives of fatty acids may also be present, and these derivatives may react or decompose to form carboxylic acids.

[0015] Various metals may be present in fuel compositions. This may be due to contamination of the fuel during manufacture, storage, transport or use, or due to contamination of fuel additives. Metallic substances may also be intentionally added to fuels. For example, transition metals are sometimes added as fuel-based catalysts to improve the performance of diesel particulate filters.

[0016] The inventors believe that one of the many causes of injector sticking is the reaction of metal or ammonium species in the fuel with carboxylic acid species. One example of injector sticking is due to sodium contamination in the fuel. Sodium contamination can occur for a variety of reasons. For example, sodium hydroxide may be used in the washing step in the hydrodesulfurization process and may cause contamination. Sodium may also be present due to the use of sodium-containing corrosion inhibitors in the pipeline. Another example may be caused by the presence of calcium, such as calcium generated by interaction with lubricants or contamination with it, or from calcium chloride used in the salt drying process in the refinery. Other metal contamination may occur, such as during transportation, due to water deposits (bottoms).

[0017] Metal contamination of diesel fuel and the resulting formation of carboxylates are considered to be a significant cause of injector sticking. Varnish formation is another major cause of injector sticking.

[0018] One approach to combating IDID and injector sticking caused by carboxylates is to try to eliminate the source of the metal contamination and / or carboxylic acid, or to try to ensure that the particularly problematic carboxylic acid is eliminated. This approach has not been completely successful and requires the addition of additives to control IDID.

[0019] Deposit control additives are often added to the fuel to eliminate deposits in the injector nozzles or at the injector tips. These may be referred to herein as "external injector deposits". Additives are also used to control deposits on vehicle fuel filters. However, it has been found that additives that can be used to control "external deposits" and fuel filter deposits are not always effective in controlling IDID. One challenge facing additive formulators is to provide more effective detergents.

[0020] The object of the present invention is to provide methods and uses for improving the performance of diesel engines, especially diesel engines with high pressure fuel systems. For example, this can be achieved by preventing or reducing the formation of IDIDs and / or reducing or removing existing IDIDs. The present invention provides methods and uses for controlling "external injector deposits" and / or fuel filter deposits.

[0021] Another object of the present invention is to provide an additive suitable for gasoline compositions that reduces the formation of deposits in spark ignition engines, particularly direct injection spark ignition (or DISI) engines. These are also referred to as direct injection gasoline (DIG) or gasoline direct injection (GDI) engines. These engines include an injection system in which the fuel is injected directly into the combustion chamber. Although such a system is conducive to reliable combustion, this injection strategy means that the fuel injector is subjected to high temperatures and pressures, thereby increasing the possibility of deposits formed due to high temperature degradation of the fuel. The fact that the injector is located in the combustion chamber also exposes the injector to combustion gases that may contain partially oxidized fuel and / or soot particles, which may accumulate, thereby increasing the level of deposits. The ability to provide good fuel atomization and precise control of the fuel flow rate and the duration of injection is essential for the optimal performance of these engines. Therefore, it is very important to control deposits in this area.

[0022] Reducing or preventing the formation of deposits may be considered to provide a "keep clean" property. Reducing or removing existing deposits may be considered to provide a "clean up" property. It is an object of the present invention to provide a "keep clean" and / or "clean up" property.

[0023] There are many different types of compounds known in the art that can be used as detergent additives in fuel oil compositions for controlling deposits in engines. Examples of common detergents include hydrocarbyl-substituted amines; hydrocarbyl-substituted succinimides; Mannich reaction products and quaternary ammonium salts. All of these known detergents are nitrogen-containing compounds.

[0024] The present invention particularly relates to nitrogen-free polymeric detergent compounds for diesel or gasoline fuels. Such compounds are rarely used as detergents.

[0025] According to a first aspect of the present invention, there is provided a fuel composition comprising as an additive a polymer of formula (I):

[0026]

[0027]

[0028] wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

[0029] According to a second aspect of the present invention, there is provided a method for improving engine performance, the method comprising burning in an engine a fuel composition comprising as an additive a polymer of formula (I):

[0030]

[0031] wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

[0032] According to a third aspect of the present invention, there is provided the use of a polymer of formula (I):

[0033]

[0034] It is used as an additive for a fuel composition to improve the performance of an engine burning the fuel composition; wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbon group, provided that at least 10% of all R groups are not hydrogen.

[0035] The method of the second aspect preferably involves combusting the composition of the first aspect in an engine.

[0036] Preferred features of the first, second and third aspects of the invention will now be described.Any feature of any aspect may be combined with any feature of any other aspect as appropriate.

[0037] The present invention relates to compositions, methods and uses related to polymeric fuel additives. The polymeric additive may be referred to herein as the "additive of the present invention."

[0038] The additive of the present invention can be prepared by polymerizing a dicarboxylic acid of formula (II) or its anhydride and then esterifying the polymerized diacid:

[0039]

[0040] In a preferred embodiment, the polymer additive of the present invention is prepared by polymerizing the reaction product of a dicarboxylic acid compound of formula (II) or its anhydride and an alcohol. Therefore, the additive of the present invention is preferably prepared by forming an ester of a dicarboxylic acid of formula (II) and an alcohol of formula ROH; then polymerizing the ester.

[0041] The polymerization is preferably carried out by a free radical initiated method.

[0042] The dicarboxylic acid compound of formula (II) comprises a free carboxylic acid group and / or anhydride group.

[0043] When the compounds of formula (II) contain anhydride groups, they may be internal cyclic anhydrides, where two carboxylic acid groups within the structure of formula (II) react together to form an anhydride, for example as shown in formula (III):

[0044]

[0045] Such a cyclic anhydride group can be considered to be equivalent to two free carboxylic acid groups.

[0046] In some embodiments, the anhydride can be an acyclic anhydride.

[0047] When anhydrides are used, the polymer may optionally be hydrolyzed to provide the acid residues. Suitable hydrolysis conditions will be known to those skilled in the art.

[0048] The additive of the present invention is a polymer of formula (I):

[0049]

[0050] n is at least 4. Preferably, n is at least 6, more preferably at least 8, for example at least 10. Suitably, n is from 10 to 200, preferably from 15 to 80, more preferably from 20 to 60, for example 25 to 50.

[0051] x may be 0-10, such as 0-6, 0-4 or 0-2.

[0052] y may be 0-10, such as 0-6, 0-4 or 0-2.

[0053] Preferably, x+y is at least 1. Preferably, x+y is less than 20, preferably less than 15, more preferably less than 10. Preferably, x+y is less than 8, preferably less than 6.

[0054] Preferably, x+y is 1-10, more preferably 1-6, such as 1-4.

[0055] Preferably, x is 0 and y is at least 1. Preferably, y is 1 to 10, preferably 1 to 6.

[0056] In some preferred embodiments, x is 0 and y is 1-4, preferably 1-3.

[0057] Most preferably, x+y=1.

[0058] For the avoidance of doubt, the definitions of x and y apply to the structures represented by Formula (I), Formula (II) and Formula (III).

[0059] Some preferred dicarboxylic acid compounds for use in preparing the additives of the present invention are itaconic acid, itaconic anhydride, 2-methyleneglutaric acid, 2-methyleneglutaric anhydride, 2-methyleneadipic acid, 2-methyleneadipic anhydride, and isomers and / or mixtures thereof.

[0060] A particularly preferred dicarboxylic acid compound for use herein is itaconic acid, which has the formula (IV):

[0061]

[0062] A preferred anhydride is itaconic anhydride, which has formula (V):

[0063]

[0064] The additive of the present invention is preferably a polymerization product of a dicarboxylic acid or its anhydride and an alcohol.

[0065] Suitably, the alcohol has from 1 to 60 carbon atoms. Preferably, the alcohol has at least 4 carbon atoms.

[0066] Any suitable alcohol, preferably an alcohol having at least 4 carbon atoms, may be used to prepare the additives of the present invention.

[0067] The alcohol may be a monohydric alcohol or a polyhydric alcohol. Monohydric alcohols are preferred.

[0068] Preferably, the alcohol is of the formula H-(OR 2 ) m -OR 1 A compound wherein R 2 is an optionally substituted alkylene or arylene group; R 1 is hydrogen or an optionally substituted hydrocarbon group; and m is 0 or a positive integer; provided that when R 1 When it is hydrogen, m is not 0.

[0069] In the polymer additive of formula (I) of the present invention, each group R is suitably hydrogen or a group of formula (OR 2 ) m OR 1 The group.

[0070] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, which is well known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:

[0071] (i) hydrocarbon groups, i.e., aliphatic (which may be saturated or unsaturated, straight chain or branched, e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic (including aliphatic and alicyclic substituted aromatic) substituents, as well as cyclic substituents wherein the ring is completed by another part of the molecule (e.g., two substituents together form one ring);

[0072] (ii) substituted hydrocarbon groups, i.e. substituents containing non-hydrocarbon groups which, in the context of the present invention, do not alter the predominantly hydrocarbon nature of the substituent (e.g. halogen (e.g. chlorine, fluorine or bromine), hydroxy, alkoxy (e.g. C1 to C4 alkoxy), keto, acyl, cyano, mercapto, amino, amide, nitro, nitroso, sulfoxide, nitryl and carboxyl);

[0073] (iii) heterosubstituents, i.e., in the context of the present invention, substituents which, although predominantly hydrocarbon in nature, contain elements other than carbon in a ring or chain which otherwise consists of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and include substituents such as pyridyl, furyl, thienyl and imidazolyl. Generally, no more than two non-hydrocarbon substituents, and preferably no more than one non-hydrocarbon substituent, will be present for every ten carbon atoms in the hydrocarbyl group; usually, no non-hydrocarbon substituents will be present in the hydrocarbyl group.

[0074] In some embodiments, m is 0, and the additive of the present invention can be represented by the formula R 1 In such embodiments, R 1 is an optionally substituted hydrocarbon group. 1 is an optionally substituted alkyl, alkenyl, aryl, alkaryl or aralkyl group.

[0075] In some preferred embodiments, R 1 is an optionally substituted hydrocarbon group having at least 4 carbon atoms. 1 is an optionally substituted hydrocarbon group having 5 to 200 carbon atoms, suitably 6 to 50 carbon atoms, preferably 8 to 30 carbon atoms.

[0076] R 1 It may be an optionally substituted alkyl, alkenyl or aryl group having at least 5 carbon atoms.

[0077] In some embodiments, R 1 is an optionally substituted C5 to C 200 Alkyl or alkenyl, preferably C6 to C50 Alkyl or alkenyl, preferably C8 to C 30 Alkyl or alkenyl.

[0078] R 1 It may be substituted by one or more groups selected from the following: halogen (e.g., chlorine, fluorine or bromine), nitro, hydroxy, thiol, sulfoxide, amino, nitroxyl, acyl, carboxyl, alkyl (e.g., C1 to C4 alkyl), alkoxy (e.g., C1 to C4 alkoxy), amide, keto, sulfoxide and cyano.

[0079] In some embodiments, R 1 has at least 6 carbon atoms. 1 Can have more than 8 carbon atoms. In some embodiments, R 1 There may be more than 10 carbon atoms, such as more than 12 carbon atoms, more than 14 carbon atoms, or more than 16 carbon atoms.

[0080] In some embodiments, R 1 Having less than 30 carbon atoms, preferably less than 28 carbon atoms, suitably less than 26 carbon atoms.

[0081] In some preferred embodiments, R 1 It is an alkyl or alkenyl group having 6 to 50 carbon atoms, preferably 8 to 30 carbon atoms.

[0082] Preferably, R 1 is an unsubstituted alkyl or alkenyl. In some preferred embodiments, R 1 is an unsubstituted alkenyl group.

[0083] R 1 Can be straight chain or branched. In some embodiments, R 1 is an unsubstituted straight-chain or branched alkyl or alkenyl group having 4 to 50 carbon atoms, preferably 6 to 30 carbon atoms.

[0084] In some embodiments, R 1 is an optionally substituted alkyl, alkenyl, aryl, alkaryl or aralkyl group having less than 20 carbon atoms, suitably less than 16 carbon atoms.

[0085] In some embodiments, R 1 It is an alkyl group, alkenyl group, aryl group, alkaryl group or aralkyl group having 6 to 16 carbon atoms.

[0086] In some embodiments, R 1 is an unsubstituted alkyl, aryl, alkaryl or aralkyl group having less than 16 carbon atoms.

[0087] In some embodiments, R 1is an unsubstituted alkyl, aryl, alkaryl or aralkyl group having less than 12 carbon atoms, suitably less than 10 carbon atoms.

[0088] In some embodiments, R 1 It is an alkylaryl group.

[0089] In one embodiment, R 1 It's benzyl.

[0090] In some embodiments, R 1 The alkyl group is preferably an unsubstituted alkyl group having 6 to 50 carbon atoms, preferably 8 to 30 carbon atoms, for example 12 to 24 carbon atoms.

[0091] In some embodiments, R 1 For the group CH3(CH2) x , wherein x is 4 to 23, preferably 9 to 19.

[0092] In some preferred embodiments, R 1 C 12 To C 18 alkyl.

[0093] R 1 The alkyl group may be linear, branched or cyclic.

[0094] Alcohol R suitable for use herein 1 OH includes hexanol, octanol, nonanol, decanol, dodecanol, tetradecanol, cetyl alcohol, stearyl alcohol, 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol, isotridecanol, cyclohexanol, cyclooctanol and benzyl alcohol.

[0095] In some embodiments, R 1 It is an alkenyl group, preferably an unsubstituted alkenyl group having 5 to 36 carbon atoms, more preferably 10 to 30 carbon atoms, suitably 10 to 24 carbon atoms.

[0096] R 1 It can be a straight chain, branched or cyclic alkenyl. Suitable alkenyl alcohols include citronellol, oleyl alcohol, 9-decene-1-ol, cis-3-hexene-1-ol, trans-2-hexene-1-ol, 5-hexene-1-ol, 6-methyl-5-heptene-2-ol, 1-octen-3-ol, trans-2-octen-1-ol and 10-undecene-1-ol.

[0097] In some embodiments, alkenyl alcohols can be obtained from naturally occurring fatty acids, such as by chemical reduction. Such materials can include mixtures of alkenyl alcohols. Examples include oleyl alcohol, linoleyl alcohol, and fatty alcohols derived from fatty acids, such as tall oil, coconut oil, or palm kernel oil fatty acids.

[0098] In some embodiments, the alkenyl alcohol may be derived from a terpene. Examples of such alkenyl alcohols include linalool, fenchol, terpineol, borneol, isoborneol, citrol, geraniol, citronellol, phytol, and nerol.

[0099] In some preferred embodiments, the alcohol is C 18 Alcohols, such as stearyl alcohol or oleyl alcohol.

[0100] In some embodiments, oleyl alcohol is particularly preferred.

[0101] In some preferred embodiments, R 1 is a branched saturated alkyl group, for example a branched saturated C5 to C 24 alkyl.

[0102] Suitable branched alcohols for use herein include 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol and isotridecanol.

[0103] In some embodiments, 2-ethylhexanol is particularly preferred.

[0104] In some embodiments, R 1 is a short chain hydrocarbon group, such as a C1 to C3 alkyl group. In such an embodiment, the alcohol may be selected from methanol, ethanol, propanol and isopropanol.

[0105] In some embodiments, mixtures of alcohols can be used. In some embodiments, mixtures of alcohols can be used that include at least one short chain alcohol having 1 to 3 carbon atoms and at least one alcohol having 4 or more carbon atoms, such as at least one alcohol having 1 to 3 carbon atoms and at least one alcohol having 6 to 50 or 8 to 30 carbon atoms.

[0106] In a preferred embodiment, a mixture of isopropanol and 2-ethylhexanol is used. Preferably, the molar ratio of isopropanol to 2-ethylhexanol is from 4:1 to 1:4.

[0107] Those skilled in the art will appreciate that the formula R 1 Commercial sources of OH alcohols will typically contain mixtures of compounds, such as mixtures of isomers and / or mixtures of homologs.

[0108] Some alcohols suitable for use herein include mixed C 16 To C 18 A monounsaturated alcohol called cetearyl alcohol.

[0109] In some embodiments, m is not 0, and the additive of the present invention can be suitably represented by the formula H-(OR 2 ) m -OR 1 of alcohol formed.

[0110] In such embodiments, R 1 R is hydrogen or an optionally substituted hydrocarbon group. 1 May be as defined above.

[0111] R 2 is an optionally substituted arylene or alkylene. 2 is an optionally substituted alkylene group.

[0112] Preferably, R 2 is an unsubstituted alkylene group.

[0113] Preferably, R 2 is an optionally substituted alkylene group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, suitably 1 to 10 carbon atoms, for example 2 to 6 or 2 to 4 carbon atoms.

[0114] Preferably, R 2 is an unsubstituted alkylene group having 1 to 50 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, suitably 2 to 6 carbon atoms, for example 2 to 4 carbon atoms. R may be linear or branched.

[0115] Appropriately, R 2 It can be ethylene, propylene, butylene, pentylene or hexylene. 2 When there are more than 2 carbon atoms, any isomers may exist. Preferably, R 2 It is ethylene or propylene, and most preferably is propylene.

[0116] R 2 May contain mixed isomers. For example, when R 2 In the case of propylene, the polyol may contain -CH2CH(CH3)- and -CH(CH3)CH2- moieties in any order within the chain.

[0117] R 2 Mixtures of different groups may be included, for example ethylene, propylene or butylene units. In such embodiments, block copolymer units are preferred.

[0118] R 2 Preferably, ethylene, propylene or butylene. R can be n-propylene or n-butylene or isopropylene or isobutylene. For example, R 2 It may be -CH2CH2-, -CH2CH(CH3)-, -CH2C(CH3)2, -CH(CH3)CH(CH3)- or -CH2CH(CH2CH3)-.

[0119] Preferably, R 2 More preferably, R 2 is -CH2CH2- or -CH(CH3)CH2-. Most preferably, R 2 It is -CH(CH3)CH2-.

[0120] In some embodiments, m is at least 1. Preferably, n is 1 to 200, preferably 1 to 50, more preferably 1 to 30, more preferably 1 to 24, preferably 1 to 20, suitably 1 to 16.

[0121] In some preferred embodiments, m is from 8 to 20.

[0122] Those skilled in the art will appreciate that the formula H-(OR 2 ) m -OR 1 Commercial sources of alcohols typically contain mixtures of compounds, for example wherein m may be from 10 to 20.

[0123] In some preferred embodiments, wherein m is not 0, R 1 is an optionally substituted alkyl, alkenyl or aryl, suitably an optionally substituted alkyl or alkenyl. 1 It has 4 to 50 carbon atoms, preferably 4 to 40 carbon atoms, and more preferably 10 to 30 carbon atoms. 1 It can be straight chain or branched. Preferably, R 1 For straight chain.

[0124] In some embodiments, R 1 is a substituted alkyl or alkenyl group, suitably a substituted alkyl group. Suitable substituents are hydroxyl and ester groups. In some embodiments, R 1 is 2-hydroxyalkyl, alkenyl or aryl.

[0125] Appropriately, R 1 is an unsubstituted alkyl or alkenyl group. 1 It is an alkyl group, preferably an unsubstituted alkyl group.

[0126] Appropriately, R 1It is selected from an alkyl group having 1 to 40, preferably 6 to 30, more preferably 10 to 20 carbon atoms.

[0127] In some embodiments, R 1 is a C4 to C30 alkyl or alkenyl group, m is not 0, and the additive of the present invention is prepared from an alkyl or alkenyl ether of a polyol, such as an ether of polyethylene glycol, polypropylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol or tripropylene glycol.

[0128] Some particularly preferred alcohols for use in preparing the additives of the present invention have the formula CH3(CH2) a O(CH2CH(CH3)O) b H or an isomer thereof, wherein a is 4 to 30, preferably 8 to 20, more preferably 10 to 15, and b is 1 to 30, preferably 5 to 25, more preferably 10 to 20. In a preferred embodiment, a is 13 and b is 15.

[0129] In some embodiments, m is 1, R 1 is hydrogen and R 2 Selected from ethylene, propylene and 2-hydroxypropylene. Thus, the alcohol may be a short-chain polyol having 2 or 3 carbon atoms, preferably selected from ethylene glycol, propylene glycol and glycerol.

[0130] Formula H-(OR 2 ) m -OR 1 The alcohol may be selected from:

[0131] - short-chain alcohols having 1 to 3 carbon atoms;

[0132] - short-chain polyols having 2 or 3 carbon atoms;

[0133] -Formula CH3(CH2) a OH-alkanol or its isomers, wherein a is 4 to 23;

[0134] - a branched or cyclic alkyl alcohol, wherein m is 0 and R 1 having 6 to 24 carbon atoms;

[0135] -alkenyl alcohol, wherein n is 0 and R 1 having 6 to 24 carbon atoms;

[0136] - glycol ethers, wherein m is not 0; and

[0137] - mixtures thereof.

[0138] Formula H-(OR 2 ) m -OR 1 The alcohol may be selected from:

[0139] -Formula CH3(CH2) a OH-alkanol or its isomers, wherein a is 4 to 23;

[0140] - a branched or cyclic alkyl alcohol, wherein m is 0 and R 1 having 6 to 24 carbon atoms;

[0141] -alkenyl alcohol, wherein n is 0 and R 1 has 6 to 24 carbon atoms; and

[0142] - glycol ethers, wherein m is not zero.

[0143] Preferred formula CH3(CH2) a The OH-containing alkanols include stearyl alcohol, myristyl alcohol, cetyl alcohol, octanol, hexanol, nonanol, decanol, and dodecanol.

[0144] Preferred branched or cyclic alkyl alcohols wherein m is 0 include cyclohexanol, cyclooctanol, 2-propylheptanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-ethyl-1-butanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol and isotridecanol.

[0145] Preferred alkenyl alcohols wherein m is 0 include citronellol, oleyl alcohol, 9-decen-1-ol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, 5-hexen-1-ol, 6-methyl-5-hepten-2-ol, 1-octen-3-ol, trans-2-octen-1-ol and 10-undecen-1-ol.

[0146] Preferred glycol ethers wherein m is not 0 include those of the formula CH3(CH2) a O(CH2CH(CH3)O) b H or an isomer thereof, wherein a is 10 to 15 and b is 10 to 20.

[0147] The additives of the present invention can be prepared by polymerizing a dicarboxylic acid and then esterifying some or all of the acid groups on the polymerized acid.

[0148] Preferably, the additive of the present invention is prepared by reacting dicarboxylic acid compounds with alcohols, and then polymerizing the resulting esters. In some embodiments, dicarboxylic acid and alcohol are preferably reacted in a molar ratio of 15:1 to 1:15, suitably 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, such as 1.5:1 to 1:1.5 or 1.2:1 to 1:1.2. For the avoidance of doubt, molar ratio refers to the molar number of each type of molecule reacted, rather than the number of functional groups reacted. Therefore, a molar ratio of 1:1 refers to the reaction of one mole of dicarboxylic acid compounds with one mole of alcohols, regardless of the number of acid / hydroxyl groups present in each compound.

[0149] In some particularly preferred embodiments, the dicarboxylic acid compound and the alcohol are reacted in a molar ratio of about 1 : 1. Unless otherwise indicated herein, "about" means within 10% of the specified value.

[0150] In some preferred embodiments, the dicarboxylic acid compound and the alcohol are reacted in a molar ratio of at least 1:1.5, preferably at least 1:1.6, more preferably at least 1:1.7, suitably at least 1:1.8, for example at least 1:1.9. The dicarboxylic acid compound and the alcohol can be reacted in a ratio of 1:1.5 to 1:2.5, for example 1:1.8 to 1:2.2.

[0151] In some preferred embodiments, the dicarboxylic acid compound and the alcohol are reacted in a ratio of about 1: 2. In such embodiments, substantially all of the acid groups are esterified.

[0152] The dicarboxylic acid compound and the alcohol react to form an ester. In some preferred embodiments, the dicarboxylic acid and the alcohol react in a molar ratio of about 1:1. The reaction product of the dicarboxylic acid and the alcohol may include a mixture of compounds. Preferably, the reaction product mainly comprises monoesters. However, in addition to unreacted diacids, some diesters may also be present. When x≠y, two different monoesters can be formed even with a single alcohol. Alcohol mixtures may also be used to produce additional mixtures in the product.

[0153] The reaction product obtained after the reaction of the dicarboxylic acid and the alcohol is then polymerized.

[0154] According to a fourth aspect of the present invention, there is provided a method for preparing an additive of formula (I):

[0155]

[0156] The method comprises the following steps:

[0157] (i) reacting a dicarboxylic acid of formula (II) or its anhydride with an alcohol:

[0158]

[0159] (ii) the reaction product obtained in the polymerization step (i);

[0160] wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

[0161] According to a fifth aspect of the present invention, there is provided a method for preparing a fuel composition, the method comprising quantitatively adding a polymer additive of formula (I) to the fuel:

[0162]

[0163] wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

[0164] Preferably, the method of the fifth aspect involves the following steps:

[0165] (i) reacting a dicarboxylic acid of formula (II) or its anhydride with an alcohol:

[0166]

[0167] (ii) polymerizing the reaction product defined in step (ii) to provide an additive of formula (I);

[0168]

[0169] (iii) dosing the additive into the fuel;

[0170] wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

[0171] Preferred features of the fourth and fifth aspects are as defined in relation to the first, second and third aspects.

[0172] Preferred features of the invention will now be further described.

[0173] In the polymer additive of formula (I) of the present invention, at least 10% of all R groups are not hydrogen. Thus, at least 10% of all acid residues in the molecule are esterified. For the avoidance of doubt, the number of esterified groups is a molar ratio rather than a weight ratio.

[0174] Preferably, at least 15% of all R groups in the additive of formula (I) are not hydrogen, more preferably at least 20%, suitably at least 25%, more preferably at least 30%, for example at least 35% or at least 40% of all R groups in the additive of formula (I) are not hydrogen.

[0175] Up to 100% of all R groups may be non-hydrogen, for example up to 95%, suitably up to 90%, preferably up to 80%, more preferably up to 75%, for example up to 70%, up to 65% or up to 60% of all R groups in the additive of formula (I) are non-hydrogen.

[0176] R groups other than hydrogen are optionally substituted hydrocarbyl groups as previously defined herein.

[0177] In some preferred embodiments, 30% to 70%, preferably 40% to 60%, more preferably 45% to 55% of all R groups in the additive of formula (I) are not hydrogen.

[0178] In this preferred embodiment, about half of all R groups in the additive of formula (I) are not hydrogen. Thus, about half of the acid groups in the additive of formula (I) are esterified.

[0179] In those preferred embodiments, wherein the additive of formula (I) is prepared by polymerizing the reaction product of a dicarboxylic acid and an alcohol, the additive is prepared by polymerizing primarily a monoester.

[0180] In such embodiments of the structure represented by formula (I), preferably one R group in each monomer unit is hydrogen and the other is an optionally substituted hydrocarbyl group.

[0181] In some preferred embodiments, at least 90%, preferably at least 95%, and more preferably at least 99% of all R groups in the additive of formula (I) are not hydrogen.

[0182] In this preferred embodiment, substantially all of the R groups in the additive of formula (I) are not hydrogen. Thus, a majority of the acid groups present in the additive of formula (I) are esterified.

[0183] In such embodiments of the structure represented by formula (I), in each monomer unit, each R group is an optionally substituted hydrocarbyl group.

[0184] Suitable conditions for carrying out the esterification reaction of step (i) of the process of the fourth aspect will be known to those skilled in the art.In some preferred embodiments, an acid catalyst is used.

[0185] Step (ii) of the process of the fourth aspect and a preferred embodiment of the fifth aspect involves polymerising the reaction product obtained in step (i).

[0186] The polymerization may be suitably achieved by the addition of a free radical initiator. Suitable free radical initiators will be known to those skilled in the art and include: azo compounds such as azobisisobutyronitrile (AIBN); hydroperoxides such as cumene hydroperoxide, tert-butyl hydroperoxide, methyl ethyl ketone hydroperoxide; peroxides such as di-tert-butyl peroxide, tert-butyl peroxypivalate, diisopropylbenzene peroxide, benzoyl peroxide 1,1'azobis(cyclohexanecarbonitrile) (ABCN); and persulfates such as ammonium persulfate, sodium persulfate or potassium persulfate.

[0187] Suitable amounts of free radical initiators and reaction conditions will be known to those skilled in the art.

[0188] The additive of the present invention is preferably a polymerization product of a carboxylic acid and an alcohol.

[0189] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) or its anhydride and a dicarboxylic acid compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an optionally substituted hydrocarbon group having 6 to 30, preferably 6 to 24 carbon atoms.

[0190] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) or its anhydride and a dicarboxylic acid compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is a (preferably branched) alkyl radical having 6 to 30, preferably 6 to 24 carbon atoms.

[0191] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) or its anhydride and a dicarboxylic acid compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an optionally substituted alkyl or alkenyl group having 6 to 30, preferably 6 to 24 carbon atoms.

[0192] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) (preferably wherein x+y is less than 6) or an anhydride thereof and a dicarboxylic acid compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 It is an alkenyl group having 6 to 30, preferably 6 to 24 carbon atoms.

[0193] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) or its anhydride and a dicarboxylic acid compound of formula H-(OR 2 ) m -OR 1 The polymerization product of an alcohol wherein n is 1 to 24, R 2 is ethylene, propylene or isopropylene, and R 1It is an unsubstituted alkyl group having 6 to 30, preferably 6 to 24 carbon atoms.

[0194] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) (preferably wherein x+y is less than 6) or an anhydride thereof and a dicarboxylic acid compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an alkyl group having 1 to 3 carbon atoms.

[0195] In some embodiments, the additive of the present invention is a dicarboxylic acid compound of formula (II) or its anhydride and a dicarboxylic acid compound of formula H-(OR 2 ) m -OR 1 The polymerization products of alcohols wherein n is 1, R 2 is ethylene, propylene or 2-hydroxypropylene, and R 1 For hydrogen.

[0196] In some embodiments, the additive of the present invention is a polymerization reaction product of itaconic acid or its anhydride and an alcohol selected from 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol and isotridecanol.

[0197] In some embodiments, the additive of the present invention is itaconic acid or its anhydride and a compound of formula H-(OR 2 ) m -OR 1 The polymerization product of an alcohol of 1 It is an unsubstituted alkyl group having 6 to 30, preferably 6 to 24 carbon atoms.

[0198] In some embodiments, the additive of the present invention is a polymerization reaction product of itaconic acid or its anhydride and an enol selected from citronellol, oleyl alcohol, 9-decen-1-ol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, 5-hexen-1-ol, 6-methyl-5-hepten-2-ol, 1-octen-3-ol, trans-2-octen-1-ol and 10-undecen-1-ol.

[0199] In some embodiments, the additive of the present invention is a polymerization reaction product of itaconic acid or its anhydride and an enol selected from the group consisting of methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, and glycerol.

[0200] In some embodiments, the additive of the present invention is a polymerization reaction product of itaconic acid or its anhydride and citronellol or oleyl alcohol (preferably oleyl alcohol).

[0201] In some particularly preferred embodiments, the additive of the present invention is the polymerization product of itaconic acid or its anhydride and 2-ethylhexanol.

[0202] In some particularly preferred embodiments, the additive of the present invention is the polymerization reaction product of itaconic acid or its anhydride and a mixture of isopropanol and 2-ethylhexanol.

[0203] In a preferred embodiment, the additive of the present invention is a polymerization reaction product of itaconic acid or its anhydride and 2-ethylhexanol, wherein the weight average molecular weight of the polymer is 2000 to 50000, preferably 4000 to 30000, more preferably 5000 to 20000, for example 6000 to 15000, suitably 8000 to 12000.

[0204] The weight average molecular weight can be measured by gel permeation chromatography.

[0205] Suitably, the polymer additive of the present invention is present in the diesel fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 5 ppm, suitably at least 10 ppm, preferably at least 15 ppm.

[0206] Suitably, the polymer additive of the invention is present in the fuel composition in an amount of less than 10000 ppm, preferably less than 1000 ppm, preferably less than 500 ppm, preferably less than 300 ppm, for example less than 250 ppm or less than 200 ppm, or less than 150 ppm.

[0207] Suitably, the polymer additive is present in the fuel composition in an amount of from 1 to 10000 ppm, preferably from 5 to 1000 ppm, more preferably from 10 to 500 ppm or from 10 to 200 ppm.

[0208] In this specification, any reference to ppm refers to parts per million by weight. Treat rate values ​​given in parts per million (ppm) represent the amount of active agent present in the composition and do not include any diluents, carriers or other materials that may be present.

[0209] The diesel fuel composition of the invention may comprise a mixture of two or more polymeric additives as defined herein. In such embodiments, the amounts stated above refer to the total amount of all such additives present in the composition.

[0210] The polymer additive compound may be prepared from a monomer mixture including a mixture formed by reacting a mixture of different alcohols with a dicarboxylic acid compound and / or a mixture formed by reacting an alcohol with a mixture of dicarboxylic acid compounds and / or a compound formed by reacting a mixture of alcohols with a mixture of dicarboxylic acid compounds.

[0211] It will be appreciated by those skilled in the art that even if prepared from a single acid and a single alcohol, the polymer will contain a mixture of compounds.

[0212] The use of a mixture may result from the availability of starting materials, or a particular mixture may be deliberately chosen for the benefit to be gained. For example, a particular mixture may result in improved processing capabilities, an overall improvement in performance, or a synergistic improvement in performance.

[0213] In this specification, any reference to the "additive" or "the additive" of the present invention includes embodiments in which a mixture of compounds is present. In embodiments in which two or more compounds are present, a mixture may be present due to a mixture of starting materials used to prepare the additive compounds. Alternatively and / or additionally, two or more preformed polymer additive compounds may be mixed into the fuel composition.

[0214] The fuel composition of the first aspect of the present invention may be a diesel fuel composition or a gasoline fuel composition.

[0215] Additives can be added to fuel at any convenient point in the supply chain. For example, additives can be added to fuel at a refinery, distribution terminal, or after the fuel leaves a distribution terminal. If additives are added to fuel after the fuel leaves a distribution terminal, this is known as an aftermarket application. Aftermarket applications include situations where additives are added to fuel in a transport tanker, directly to a customer's bulk storage tank, or directly to the end user's vehicle tank. Aftermarket applications can include providing fuel additives in small bottles suitable for direct addition to fuel storage tanks or vehicle tanks.

[0216] In some preferred embodiments, the fuel composition is a diesel fuel composition.

[0217] Diesel fuel includes 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.

[0218] The diesel fuel composition used in the present invention may include a petroleum-based fuel oil, especially a middle distillate fuel oil. Such distillate fuel oils typically have a boiling point between 110° C. and 500° C., such as 150° C. and 400° C. The diesel fuel may include atmospheric or vacuum distillates, cracked gas oils or a mixture of straight run and refinery streams in any proportion, such as thermal and / or catalytic cracking and hydrocracked fractions.

[0219] 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).

[0220] The diesel fuel composition may include a renewable fuel, such as a biofuel composition or a biodiesel composition.

[0221] Diesel fuel compositions may include first generation biodiesel. First generation biodiesel contains esters of, for example, vegetable oils, animal fats and waste cooking oils. This form of biodiesel can be obtained by transesterifying oils (for example, rapeseed oil, soybean oil, canola oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow, coconut oil, jatropha oil, sunflower oil, waste cooking oil, hydrogenated vegetable oil or any mixture thereof) with alcohols (typically monohydric alcohols) in the presence of a catalyst.

[0222] The diesel fuel composition may comprise 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, such as using hydroprocessing, such as the H-Bio process developed by Petrobras. The properties and qualities of second generation biodiesel may be similar to petroleum-based fuel oil streams, such as renewable diesel produced from vegetable oils, animal fats, etc., and is sold by ConocoPhillips as Renewable Diesel and by Neste as NExBTL.

[0223] The diesel fuel composition may comprise third generation biodiesel. Third generation biodiesel utilizes gasification and Fischer-Tropsch technologies, including those described 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) and thereby broaden the feedstock base.

[0224] The diesel fuel composition may contain mixtures of any or all of the above diesel fuel compositions.

[0225] In some embodiments, the diesel fuel composition can be a mixed diesel fuel that comprises biodiesel. In this type of mixture, biodiesel can exist with for example 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99% amount at the most.

[0226] In some embodiments, the fuel composition may comprise pure biodiesel.

[0227] In some preferred embodiments, the fuel composition comprises at least 5 wt. % biodiesel.

[0228] In some embodiments, the fuel composition may include neat GTL fuel.

[0229] In some embodiments, the fuel composition may include a mixture of first generation biodiesel and second generation biodiesel (or renewable diesel), for example a mixture including 80% by volume first generation biodiesel and 20% by volume second generation biodiesel.

[0230] 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.

[0231] The diesel fuel composition used in the present invention may contain a relatively high sulphur content, for example greater than 0.05% by weight, such as 0.1% or 0.2%.

[0232] 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%, especially at most 0.015%. Fuels with even lower levels of sulphur are also suitable, for example fuels with less than 50 wtppm, preferably less than 20 wtppm, for example 10 wtppm or less sulphur.

[0233] The diesel fuel composition of the present invention preferably comprises at least 5 wt% biodiesel and less than 50 ppm sulphur.

[0234] Diesel fuel compositions of the present invention may comprise one or more additional additives, such as those common in diesel fuels. 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 respective appropriate amounts of these types of additives will be known to those skilled in the art.

[0235] In some embodiments, the diesel fuel compositions of the present invention comprise a corrosion inhibitor. Suitable corrosion inhibitors are commercially available and known to those skilled in the art.

[0236] In some embodiments, the diesel fuel composition of the present invention comprises a lubricity improver. Suitable lubricity improvers are commercially available and known to those skilled in the art. The lubricity improvers preferably used herein include tall oil fatty acids and ester compounds. Examples of suitable ester compounds include the reaction product of glycerol monooleate and ethylene glycol with alkenyl-substituted succinic anhydride.

[0237] In some embodiments, the diesel fuel compositions of the present invention comprise an antifoam additive. Suitable antifoam additives are commercially available and known to those skilled in the art.

[0238] In some preferred embodiments, the diesel fuel composition of the present invention comprises one or more additional detergents. Preferred are nitrogen-containing detergents.

[0239] One or more additional detergents may be added to the fuel separately from the polymeric additive of formula (I).In some embodiments, one or more additional detergents may be dosed into the fuel together with the polymeric additive of formula (I) as part of an additive composition.

[0240] According to a sixth aspect of the present invention, there is provided an additive composition comprising: a polymer of formula (I):

[0241]

[0242] wherein n is at least 4, x may be 0 or a positive integer, y may be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen;

[0243] one or more additional cleaning agents, preferably one or more additional nitrogen-containing cleaning agents; and a diluent or carrier.

[0244] Preferred features of the invention described in relation to the first to fifth aspects apply appropriately to the sixth aspect.Further preferred features of all aspects of the invention will now be described.

[0245] One or more additional cleaning agents may be selected from:

[0246] (i) quaternary ammonium salt additives;

[0247] (ii) products of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol;

[0248] (iii) the reaction product of a carboxylic acid derived acylating agent and an amine;

[0249] (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine;

[0250] (v) salts formed by reaction of carboxylic acids with di-n-butylamine or tri-n-butylamine;

[0251] (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine compound or salt, the product comprising at least one aminotriazole group;

[0252] (vii) substituted polycyclic aromatic hydrocarbon detergent additives; and

[0253] (viii) Partial esters of substituted succinic acids.

[0254] Preferably, the one or more additional cleaning agents are selected from one or more of the following:

[0255] (i) quaternary ammonium salt additives;

[0256] (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and

[0257] (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

[0258] The weight ratio of the additive of the present invention to the nitrogen-containing detergent is suitably from 10:1 to 1:10, preferably from 5:1 to 1:5, preferably from 2:1 to 1:2.

[0259] In some embodiments, the diesel fuel composition further comprises (i) a quaternary ammonium salt additive.

[0260] The quaternary ammonium salt additive is suitably the reaction product of a nitrogen-containing material having at least one tertiary amine group and a quaternizing agent.

[0261] The nitrogen-containing substance may be selected from:

[0262] (7) a hydrocarbon-substituted acylating agent and a tertiary amine group and a primary amine, a secondary amine or

[0263] reaction products of compounds having an alcohol group;

[0264] (y) a Mannich reaction product comprising a tertiary amine group; and

[0265] (z) Polyalkylene-substituted amines having at least one tertiary amine group.

[0266] Examples of quaternary ammonium salts and methods for their preparation are described in the following patents, which are incorporated herein by reference: US2008 / 0307698, US2008 / 0052985, US2008 / 0113890, and US2013 / 031827.

[0267] 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.

[0268] 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.

[0269] The preparation of nitrogen-containing substances including quaternary ammonium salt additives of component (z) is described, for example, in US 2008 / 0113890.

[0270] To form the quaternary ammonium salt additive (i), the nitrogen-containing substance having a tertiary amine group is reacted with a quaternizing agent.

[0271] The quaternizing agent may be suitably selected from esters and non-esters.

[0272] 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.

[0273] Particularly preferred additional quaternary ammonium salts for use herein are formed from methyl salicylate or dimethyl oxalate reacted with the reaction product of polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight of 700 to 1300 and dimethylaminopropylamine.

[0274] 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.

[0275] 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.

[0276] In some particularly preferred embodiments, the diesel fuel composition comprises a quaternary ammonium salt additive (ia) which is the quaternization reaction product of a hydrocarbyl-substituted succinic acid derived acylating agent and a compound capable of reacting with the acylating agent and which includes a tertiary amine group; wherein each hydrocarbyl-substituted succinic acid derived acylating agent molecule includes an average of at least 1.2 succinic acid moieties.

[0277] The preferred hydrocarbyl substituent is polyisobutylene. Such compounds are known to those skilled in the art.

[0278] The preferred hydrocarbyl substituted succinic acid derived acylating agent used to prepare additive (ia) is polyisobutenyl substituted succinic anhydride or PIBSA. Particularly preferred PIBSAs are those having a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 1300.

[0279] Hydrocarbyl-substituted succinic acid derived acylating agents are suitably prepared by reacting maleic anhydride with an olefin (e.g. polyisobutylene). The product obtained (e.g. PIBSA) still contains double bonds. Maleic anhydride is present in the resulting molecule as a succinic acid moiety.

[0280] The monomaleated PIBSA may have structure (A) or (B):

[0281]

[0282] The double bond in the monomaleated product can react with another molecule of maleic anhydride to form a bismaleated PIBSA having structure I or (D):

[0283]

[0284] Thus, a hydrocarbyl group substituted with more than one succinic acid moiety may be provided. In such embodiments, the hydrocarbyl-substituted succinic acid derived acylating agent comprises more than one succinic acid moiety per molecule.

[0285] Those skilled in the art will appreciate that the additive will typically comprise a mixture of compounds and will be prepared from a mixture of monomaleated PIBSA and bismaleated PIBSA.PIBSA can be defined according to its level of bismaleation.

[0286] One way this level can be determined is to calculate the average number of succinic acid moieties per molecule of acylating agent.

[0287] Monomaleated PIBSA has one succinic acid moiety per module.

[0288] Bismaleated PIBSA has two succinic acid moieties per molecule.

[0289] A mixture comprising monomaleated PIBSA and bismaleated PIBSA in a 1:1 molar ratio contained an average of 1.5 succinic acid moieties per PIBSA molecule.

[0290] The invention is particularly directed to the use of quaternary ammonium salts derived from hydrocarbyl-substituted acylating agents comprising an average of at least 1.2 succinic acid moieties per molecule.

[0291] Those skilled in the art will appreciate that a single molecule cannot have 1.2 succinic acid moieties. At least 1.2 succinic acid moieties refers to the average number of succinic acid moieties per molecule of acylating agent, which is equal to the sum of all succinic acid moieties present in the sample divided by the total number of acylating agent molecules having one or more succinic acid moieties present in the sample.

[0292] Preferably, the hydrocarbyl-substituted succinic acid derived acylating agent comprises an average of at least 1.21 succinic acid moieties per molecule, more preferably an average of at least 1.22 succinic acid moieties per molecule.

[0293] In some embodiments, the hydrocarbyl-substituted succinic acid derived acylating agent may comprise at least 1.23 or at least 1.24 succinic acid moieties per molecule.

[0294] In some embodiments, the hydrocarbyl-substituted succinic acid derived acylating agent may comprise at least 1.25, at least 1.26, or at least 1.27 succinic acid moieties per molecule.

[0295] In some embodiments, the hydrocarbyl-substituted succinic acid derived acylating agent may comprise at least 1.28, at least 1.29, or at least 1.30 succinic acid moieties per molecule.

[0296] The succinic acid moiety is meant to include the succinic acid residue in either the diacid or anhydride form.

[0297] In some embodiments, the quaternary ammonium compound is the quaternization reaction product of a fatty acid (eg, oleic acid) and dimethylaminopropylamine.

[0298] The hydrocarbyl-substituted succinic acid derived acylating agent is reacted with a compound capable of reacting with the acylating agent and comprising a tertiary amine group. The tertiary amine group is quaternized to provide a quaternary ammonium salt additive.

[0299] Preferably, the compound capable of reacting with the hydrocarbyl-substituted succinic acid derived acylating agent and comprising a tertiary amine group is an amine of formula I or (D):

[0300]

[0301] Where R 2 and R 3 are the same or different alkyl, alkenyl, aryl, alkaryl or aralkyl groups having 1 to 22 carbon atoms; X is a bond or an optionally substituted alkylene group having 1 to 20 carbon atoms; n is 0 to 20; m is 1 to 5; and R 4 is hydrogen or C1 to C 22 alkyl.

[0302] When using the compound of formula I, R 4 Preferably hydrogen or C1 to C 16 Alkyl, preferably C1 to C 10 alkyl, more preferably C1 to C6 alkyl. 4 When R is an alkyl group, it may be straight chain or branched. For example, it may be substituted, for example, by hydroxyl or alkoxy substituents. Preferably, R 4 More preferably, R 4 is selected from hydrogen, methyl, ethyl, propyl, butyl and isomers thereof. Most preferably, R 4 For hydrogen.

[0303] When a compound of formula (D) is used, m is preferably 2 or 3, most preferably 2; n is preferably 0 to 15, preferably 0 to 10, more preferably 0 to 5. Most preferably, n is 0 and the compound of formula (D) is an alcohol.

[0304] Preferably, a hydrocarbyl-substituted acylating agent is reacted with a diamine compound of Formula I.

[0305] Examples of compounds of Formula I suitable for use herein include 1-aminopiperidine, 1-(2-aminoethyl)piperidine, 1-(3-aminopropyl)-2-piperidin, 1-methyl-(4-methylamino)piperidine, 4-(1-pyrrolidinyl)piperidine, 1-(2-aminoethyl)pyrrolidine, 2-(2-aminoethyl)-1-methylpyrrolidine, N,N-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-dibutylethylenediamine, N,N-diethyl-1,3-diaminopropane, N,N-dimethyl-1,3-diaminopropane, N,N,N'-trimethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine, N,N-diethyl-N'-methylethylenediamine, N,N,N'-triethyl Ethylenediamine, 3-dimethylaminopropylamine, 3-diethylaminopropylamine, 3-dibutylaminopropylamine, N,N,N'-trimethyl-1,3-propylenediamine, N,N,2,2-tetramethyl-1,3-propylenediamine, 2-amino-5-diethylaminopentane, N,N,N',N'-tetraethyldiethylenetriamine, 3,3'-diamino-N-methyldipropylamine, 3,3'-iminobis(N,N-dimethylpropylamine), 1-(3-aminopropyl)imidazole and 4-(3-aminopropyl)morpholine, 1-(2-aminoethyl)piperidine, 3,3-diamino-N-methyldipropylamine, 3,3-aminobis(N,N-dimethylpropylamine), 3-(2-(dimethylamino)ethoxy)propylamine or a combination thereof.

[0306] In some preferred embodiments, the compound of formula I is selected from N,N-dimethyl-1,3-diaminopropane, N,N-diethyl-1,3-diaminopropane, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, 3-(2-(dimethylamino)ethoxy)propylamine or a combination thereof.

[0307] Examples of compounds of formula (D) suitable for use herein include alkanolamines, including but not limited to triethanolamine, N,N-dimethylaminopropanol, N,N-diethylaminopropanol, N,N-diethylaminobutanol, triisopropanolamine, 1-[2-hydroxyethyl]piperidine, 2-[2-(dimethylamino)ethoxy]-ethanol, N-ethyldiethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, N,N-diethylaminoethanol, N,N-dimethylaminoethanol ... -dimethylamino-2-methyl-1-propanol, N,N,N'-trimethyl-N'-hydroxyethyl-bisaminoethyl ether; N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine; N-(3-dimethylaminopropyl)-N,N-diisopropanolamine; N'-(3-(dimethylamino)propyl)-N,N-dimethyl-1,3-propanediamine; 2-(2-dimethylaminoethoxy)ethanol and N,N,N'-trimethylaminoethylethanolamine.

[0308] In some preferred embodiments, the compound of formula (D) is selected from triisopropanolamine, 1-[2-hydroxyethyl]piperidine, 2-[2-(dimethylamino)ethoxy]-ethanol, N-ethyldiethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, N,N-diethylaminoethanol, N,N-dimethylaminoethanol, 2-dimethylamino-2-methyl-1-propanol or a combination thereof.

[0309] A particularly preferred compound of formula (C) is N,N-dimethyl-1,3-diaminopropane (dimethylaminopropylamine).

[0310] When the compound of formula (D) reacts with a succinic acylating agent, the resulting product is a succinic ester. 4 When the succinic acylating agent reacts with a compound of formula I in which R 4 When a compound of formula I other than hydrogen is reacted, the resulting product is an amide.

[0311] To form the quaternary ammonium salt additive (ai), a hydrocarbyl-substituted succinic acid derived acylating agent is reacted with a compound capable of reacting with the acylating agent and comprising a tertiary amine group. The reaction product is then reacted with a quaternizing agent for quaternization.

[0312] The reaction product of the acylating agent and the compound comprising a tertiary amine group is preferably reacted with at least one molar equivalent of quaternizing agent per mole of tertiary amine groups present in the reaction product.

[0313] Preferably, the reaction product of the acylating agent and the compound comprising a tertiary amine group is reacted with more than one molar equivalent of quaternizing agent per mole of tertiary amine groups present in the reaction product, preferably at least 1.2 molar equivalents of quaternizing agent per mole of tertiary amine groups, more preferably at least 1.5 molar equivalents of quaternizing agent, suitably at least 1.7 molar equivalents of quaternizing agent, for example at least 1.9 molar equivalents of quaternizing agent per mole of tertiary amine groups.

[0314] Preferably, the reaction product of the acylating agent and the compound containing tertiary amine groups is reacted with two or more molar equivalents of quaternizing agent per mole of tertiary amine groups present in the reaction product, preferably at least 2.1 molar equivalents of quaternizing agent.

[0315] In some embodiments, the reaction product of the acylating agent and the compound comprising a tertiary amine group is reacted with more than 2.2 molar equivalents of quaternizing agent per mole of tertiary amine groups present in the reaction product, e.g., 2.3 to 4 molar equivalents, 2.3 to 3 molar equivalents, or 2.3 to 2.7 or 2.5 to 3 molar equivalents.

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

[0317] Suitable quaternizing agents include esters of carboxylic acids, dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides (optionally in combination with an acid), alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl substituted borates, alkyl nitrites, alkyl nitrates, hydroxides, N-oxides, chloroacetic acid or salts thereof, or mixtures thereof.

[0318] In some preferred embodiments, the quaternizing agents used to form the quaternary ammonium salt additives of the present invention are esters.

[0319] Preferred ester quaternizing agents are compounds of formula I:

[0320]

[0321] wherein R is an optionally substituted alkyl, alkenyl, aryl or alkaryl group, and R1 is a C1 to C22 alkyl, aryl or alkaryl group. The compound of formula I is suitably an ester of a carboxylic acid capable of reacting with a tertiary amine to form a quaternary ammonium salt.

[0322] Suitable quaternizing agents include esters of carboxylic acids having a pKa of 3.5 or less.

[0323] The compound of formula I is preferably an ester of a carboxylic acid selected from substituted aromatic carboxylic acids, α-hydroxycarboxylic acids and polycarboxylic acids.

[0324] In some preferred embodiments, the compound of formula I is an ester of a substituted aromatic carboxylic acid, and thus R is a substituted aryl group.

[0325] Preferably, R is a monosubstituted aryl. Preferably, R is an ortho-substituted aryl. Suitably, R is substituted by a group selected from OH, NH2, NO2 or COOMe. Preferably, R is substituted by an OH or NH2 group. Suitably, R is a hydroxy-substituted aryl. Most preferably, R is 2-hydroxyphenyl.

[0326] Preferably, R 1 is an alkyl group, an aralkyl group or an alkaryl group. 1 It may be a C1 to C16 alkyl group, preferably a C1 to C10 alkyl group, and suitably a C1 to C8 alkyl group. 1 It may be a C7 to C16 aralkyl group or an alkaryl group, and preferably a C7 to C10 aralkyl group or an alkaryl group. 1 It can be methyl, ethyl, propyl, butyl, pentyl, benzyl or an isomer thereof. 1 is benzyl or methyl. Most preferably, R 1 It is methyl.

[0327] Particularly preferred compounds of formula (III) are lower alkyl esters of salicylic acid, such as methyl salicylate, ethyl salicylate, n-propyl salicylate and isopropyl salicylate, and butyl salicylate, preferably methyl salicylate.

[0328] In some embodiments, the compound of formula I is an ester of an alpha-hydroxycarboxylic acid. In such embodiments, the compound has the following structure:

[0329]

[0330] wherein R7 and R8 are the same or different and are each selected from hydrogen, alkyl, alkenyl, aralkyl or aryl. Compounds of this type suitable for use herein are described in EP1254889.

[0331] In some embodiments, the compound of formula I is an ester of a polycarboxylic acid. This limitation refers to carboxylic acids including dicarboxylic acids and having more than two acidic moieties. In such embodiments, RCOO preferably exists in the form of an ester, that is, one or more additional acid groups present in the group R are in esterified form. However, embodiments in which not all acid groups are esterified are also within the scope of the present invention. Mixed esters of polycarboxylic acids may also be used. Preferred esters are C1 to C4 alkyl esters.

[0332] The ester quaternizing agent may be selected from the group consisting of diesters of oxalic acid, diesters of phthalic acid, diesters of maleic acid, diesters of malonic acid or diesters of citric acid.An especially preferred compound of formula (III) is dimethyl oxalate.

[0333] In a preferred embodiment, the compound of formula I is an ester of a carboxylic acid having a pKa of less than 3.5. In embodiments where the compound contains more than one acid group, we refer to the first dissociation constant.

[0334] The ester quaternizing agent may be selected from esters of carboxylic acids, wherein the carboxylic acids are selected from one or more of oxalic acid, phthalic acid, salicylic acid, maleic acid, malonic acid, citric acid, nitrobenzoic acid, aminobenzoic acid and 2,4,6-trihydroxybenzoic acid.

[0335] Preferred ester quaternizing agents include dimethyl oxalate, methyl 2-nitrobenzoate and methyl salicylate.

[0336] In some preferred embodiments, the quaternizing agent used to form the quaternary ammonium salt additive of the present invention is an ester selected from dimethyl oxalate, methyl 2-nitrobenzoate and methyl salicylate, preferably dimethyl oxalate and methyl salicylate.

[0337] Suitable non-ester quaternizing agents include dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides (optionally in combination with an acid), alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl substituted borates, alkyl nitrites, alkyl nitrates, hydroxides, N-oxides, chloroacetic acid or salts thereof, or mixtures thereof.

[0338] Suitable hydrocarbyl substituted epoxides have the formula:

[0339]

[0340] wherein R1, R2, R3 and R4 are each independently hydrogen or a hydrocarbon group having 1 to 50 carbon atoms. Examples of suitable epoxides include ethylene oxide, propylene oxide, butylene oxide, styrene oxide and stilbene oxide. Hydrocarbyl epoxides are used as quaternizing agents, optionally in combination with an acid.

[0341] The hydrocarbyl-substituted succinic acylating agent comprises two acyl groups. In some embodiments, only one of these groups reacts with the compound of formula (I) or formula (II) to form a compound having an ester or amide functionality and a free carboxylic acid. In these embodiments, if an epoxide is used as the quaternizing agent, there is no need to add a separate acid. However, in other embodiments, an acid such as acetic acid may be used.

[0342] Particularly preferred epoxide quaternizing agents are propylene oxide and styrene oxide, optionally in combination with an additional acid.

[0343] Preferred quaternizing agents for use herein include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate, chloroacetic acid or its salts, and styrene oxide or propylene oxide, optionally in combination with an additional acid.

[0344] In some embodiments, mixtures of two or more quaternizing agents may be used.

[0345] To form some preferred quaternary ammonium salt additives (ia) for use in the present invention, a compound of formula I is reacted with a compound formed by reacting a hydrocarbyl-substituted succinic acylating agent and an amine of formula I or (D).

[0346] Suitably about one equivalent of amine is added per succinic acid moiety present in the acylating agent.Thus, the proportion of amine used will generally depend on the average number of succinic acid moieties present per molecule of the acylating agent.

[0347] Particularly preferred quaternary ammonium salts (ia) for use herein are formed by reacting methyl salicylate or dimethyl oxalate with the reaction product of polyisobutylene-substituted succinic anhydride having a PIB molecular weight of 700 to 1300 and dimethylaminopropylamine; wherein the polyisobutylene-substituted succinic anhydride contains an average of at least 1.2 succinic acid moieties per molecule.

[0348] In some embodiments, the diesel fuel composition used in the present invention comprises 1 to 500 ppm, preferably 5 to 250 ppm of the additive of the present invention, and 1 to 500 ppm, preferably 5 to 250 ppm of a quaternary ammonium additive (i), preferably a quaternary ammonium additive (ia).

[0349] 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.

[0350] 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.

[0351] Amines suitable for preparing Mannich additives include monoamines and polyamines. One suitable monoamine is butylamine.

[0352] 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.

[0353] 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 of 400 to 2500, for example 500 to 1500.

[0354] In some embodiments, the diesel fuel composition of the present invention comprises from 1 to 500 ppm, preferably from 5 to 250 ppm of the additive of the present invention and from 1 to 500 ppm, preferably from 5 to 250 ppm of the Mannich additive (ii).

[0355] In some embodiments, the diesel fuel composition further comprises (iii) the reaction product of a carboxylic acid derived acylating agent and an amine.

[0356] These may also be collectively referred to herein as acylated nitrogen-containing compounds.

[0357] 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.

[0358] 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.

[0359] Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention.

[0360] Particularly preferred PIBSAs are those having a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 1300.

[0361] 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.

[0362] 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 having from 2 to about 9 amino nitrogen atoms, preferably from about 2 to about 8 nitrogen atoms, and from about 1 to about 8 ethylene groups per ethylene polyamine, wherein the number average molecular weight (Mn) of the polyisobutylene substituents is between 170 and 2800. These acylated nitrogen compounds are suitably formed by reacting an acylating agent:amino compound 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 particularly preferred embodiments, the acylated nitrogen compound is formed by reacting an acylating agent to 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.

[0363] 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.

[0364] In some embodiments, the diesel fuel composition of the present invention comprises 1 to 500 ppm, preferably 5 to 250 ppm of the additive of the present invention, and 1 to 500 ppm, preferably 5 to 250 ppm of additive (iii) which is the reaction product of an acylating agent and an amine.

[0365] In some embodiments, the diesel fuel composition comprises (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine.

[0366] Suitably, the additive comprises the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine.

[0367] Preferably, the hydrocarbon group of the hydrocarbon-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 of 200 to 2500, preferably 800 to 1200.

[0368] Hydrazine has the formula NH2-NH2. Hydrazine can be hydrated or non-hydrated. Monohydrated hydrazine is preferred.

[0369] The reaction between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine produces a variety of products, such as disclosed in US 2008 / 0060259.

[0370] 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.

[0371] Such additives may suitably be of the formula [R'(COOH) X ] y' The di-n-butylamine salt 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.

[0372] In a preferred embodiment, the carboxylic acid comprises tall oil fatty acid (TOFA).

[0373] Further preferred features of such additives are described in EP1900795.

[0374] 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.

[0375] Further preferred features of such additive compounds are as defined in US 2009 / 0282731.

[0376] In some embodiments, the diesel fuel composition further comprises (vii) a substituted polycyclic aromatic hydrocarbon detergent additive.

[0377] 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.

[0378] Further preferred features of these cleaners are described in EP1884556.

[0379] In some embodiments, the diesel fuel composition further comprises (viii) a partial ester of a substituted succinic acid.

[0380] Such preferred compounds are ester compounds, which are esters of a hydrocarbyl-substituted succinic acid or a hydrocarbyl-substituted succinic anhydride and an alcohol or a ester of the formula H-(OR) n -OR 1 wherein R is an optionally substituted alkylene group; R 1 is hydrogen or an optionally substituted hydrocarbon group, and n is 0 or a positive integer; wherein when R 1 When it is hydrogen, n is not 0.

[0381] Further preferred features of these cleaning agents are described in the applicant's co-pending applications WO2018 / 178680, WO2018 / 178678, WO2018 / 178695 and WO2018 / 178674.

[0382] The additive composition of the sixth aspect of the present invention comprises a diluent or carrier. Suitable diluents and carriers will be known to those skilled in the art. Aromatic diluents are preferably used.

[0383] The additive composition of the sixth aspect of the invention may comprise one or more further additives.

[0384] In some embodiments, the additive composition of the sixth aspect comprises a corrosion inhibitor.

[0385] In some embodiments, the additive composition of the sixth aspect comprises a lubricity improver.

[0386] In some embodiments, the additive composition of the sixth aspect comprises an anti-foam additive.

[0387] In some preferred embodiments, the additive composition of the sixth aspect comprises a polymer additive of formula (I) and an additional nitrogen-containing detergent additive selected from (i) a quaternary ammonium salt additive; (iii) a reaction product of a carboxylic acid-derived acylating agent and an amine; and mixtures thereof.

[0388] In some particularly preferred embodiments, the first aspect of the invention relates to a diesel fuel composition comprising the additive of the invention and a quaternary ammonium salt additive. The preferred quaternary ammonium salt additive is the reaction product of a nitrogen-containing substance having at least one tertiary amine group and a quaternizing agent, wherein the nitrogen-containing substance is 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. Preferably, the quaternizing agent is an ester quaternizing agent.

[0389] In some particularly preferred embodiments, a second aspect of the invention relates to a method for improving engine performance comprising burning a diesel fuel composition comprising the additive of the invention and a quaternary ammonium salt additive in an engine. Preferably, the quaternary ammonium salt additive is the reaction product of a nitrogen-containing substance having at least one tertiary amine group and a quaternizing agent, wherein the nitrogen-containing substance is 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. Preferably, the quaternizing agent is an ester quaternizing agent.

[0390] In some particularly preferred embodiments, a third aspect of the invention relates to the use of a combination of an additive of the invention and a quaternary ammonium salt additive in a fuel composition to improve the performance of an engine burning the fuel composition. The preferred quaternary ammonium salt additive is the reaction product of a nitrogen-containing substance having at least one tertiary amine group and a quaternizing agent, wherein the nitrogen-containing substance is a reaction product of an acylating agent substituted with a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group. Preferably, the quaternizing agent is an ester quaternizing agent.

[0391] In some embodiments, the fuel composition is a gasoline composition.

[0392] Thus, a first aspect of the present invention may relate to a gasoline fuel composition.

[0393] The term "gasoline" refers to a liquid fuel for spark-ignition engines (usually or preferably containing primarily or only C4-C12 hydrocarbons) and meeting international gasoline specifications, such as ASTM D-439 and EN 228. The term includes mixtures of distillate hydrocarbon fuels with oxygenated components (e.g., alcohols or ethers such as methanol, ethanol, butanol, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE)), as well as distillate fuels themselves.

[0394] In some embodiments, the gasoline fuel composition of the present invention may contain one or more additional gasoline detergents. The additional gasoline detergent may be selected from the following:

[0395] (p) hydrocarbyl-substituted polyoxyalkylene amines or polyether amines;

[0396] (q) an acylated nitrogen compound which is the reaction product of an acylating agent derived from a carboxylic acid and an amine;

[0397] I hydrocarbyl-substituted amines, wherein the hydrocarbyl substituent is substantially aliphatic and contains at least 8 carbon atoms;

[0398] (s) Mannich base additives including nitrogen-containing condensates of phenols, aldehydes and primary or secondary amines;

[0399] (t) aromatic esters of polyalkylphenoxyalkanols;

[0400] (u) additional quaternary ammonium salt additives; and

[0401] (v) Tertiary hydrocarbyl amines having up to 30 carbon atoms.

[0402] Suitable hydrocarbyl-substituted polyoxyalkylene amines or polyetheramines (p) are described in US 6217624 and US 4288612. Other suitable polyetheramines are those taught in US 5089029 and US 5112364.

[0403] The gasoline composition of the present invention may contain as an additive an acylated nitrogen compound (q) which is the reaction product of a carboxylic acid derived acylating agent and an amine. Such compounds are preferably as defined herein before in relation to component (iii) of the additives which may be added to the diesel fuel composition of the present invention.

[0404] The hydrocarbyl substituted amines I suitable for use in the gasoline fuel composition of the present invention are well known to those skilled in the art and are described in a number of patents, including U.S. Pat. Nos. 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433 and 3,822,209. These patents describe hydrocarbyl amines suitable for use in the present invention, including methods for their preparation.

[0405] The Mannich additive(s) comprises a nitrogen-containing condensate of a phenol, an aldehyde and a primary or secondary amine and is suitably as defined in relation to component (ii) of the additive suitable for use in a diesel fuel composition.

[0406] The gasoline composition of the present invention may further contain (t) an aromatic ester of a polyalkylphenoxyalkanol as an additive.

[0407] The aromatic ester component useful as the additive composition is an aromatic ester of a polyalkylphenoxyalkanol and has the following general formula:

[0408]

[0409] or a fuel-soluble salt thereof, wherein R is hydroxy, nitro or -(CH2)x-NR5R6, wherein R5 and R6 are independently hydrogen or a lower alkyl group having 1 to 6 carbon atoms, and x is 0 or 1;

[0410] R1 is hydrogen, hydroxy, nitro or -NR7R8, wherein R7 and R8 are independently hydrogen or a lower alkyl group having 1 to 6 carbon atoms;

[0411] R2 and R3 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; and

[0412] R4 is a polyalkyl group having an average molecular weight of about 450 to 5,000.

[0413] Preferred features of these aromatic ester compounds are as described in WO2011141731.

[0414] The additional quaternary ammonium salt additive (u) is suitably as defined in relation to component (i) of the additives suitable for use in diesel fuel compositions.

[0415] The tertiary hydrocarbon amine (v) suitable for use in the gasoline fuel composition of the present invention is of the formula R 1 R 2 R3 N tertiary amine, where R 1 , R 2 and R 3 Is the same or different C1-C 20 The tertiary alkyl amines are preferably tertiary alkyl amines, wherein the tertiary alkyl amines are tertiary alkyl amines, and the total number of carbon atoms does not exceed 30. Suitable examples are N,N-dimethyl-n-dodecylamine, 3-(N,N-dimethylamino)propanol and N,N-di(2-hydroxyethyl)oleylamine. Preferred features of these tertiary alkyl amines are as described in US2014 / 0123547.

[0416] The gasoline composition may also contain a carrier oil.

[0417] The carrier oil may have any suitable molecular weight. The preferred molecular weight is from 500 to 5000.

[0418] In one embodiment, the carrier oil may include oils of lubricating viscosity, including natural or synthetic oils of lubricating viscosity, oils derived from hydrocracking, hydrogenation, hydrofinishing, unrefined, refined and re-refined oils, or mixtures thereof.

[0419] Natural oils include animal oils, vegetable oils, mineral oils or mixtures thereof.Synthetic oils may include hydrocarbon oils, such as those produced by the Fischer-Tropsch reaction, and may typically be hydroisomerized Fischer-Tropsch hydrocarbons or waxes.

[0420] In another embodiment, the carrier oil may include a polyether carrier oil. In a preferred embodiment, the polyether carrier oil is a mono-terminated polyalkylene glycol, especially a mono-terminated polypropylene glycol. This type of carrier oil will be known to those skilled in the art.

[0421] The gasoline fuel composition of the present invention may contain one or more additional additives conventionally added to gasoline, such as other detergents, dispersants, antioxidants, antifreeze agents, metal deactivators, lubricity additives, friction modifiers, defogging agents, corrosion inhibitors, dyes, marking agents, octane improvers, anti-valve seat recession additives, stabilizers, demulsifiers, defoamers, odor masking agents, conductivity improvers and combustion improvers.

[0422] A second aspect of the invention relates to a method of improving engine performance.

[0423] A third aspect of the invention relates to the use of an additive in a fuel composition to improve the performance of an engine combusting the fuel composition.

[0424] Preferred features of the additives used in the second and third aspects of the invention are as defined in relation to the first aspect.

[0425] References herein to improved performance and / or elimination of deposits may apply to the second aspect and / or the third aspect of the invention.

[0426] The second and third aspects of the present invention can improve the performance of a diesel engine and / or a gasoline engine.

[0427] Preferably, the method and use of the present invention can improve the performance of a diesel engine. Such performance improvement is suitably selected from one or more of the following:

[0428] -Reduce engine power loss;

[0429] - Reduce external diesel injector deposits;

[0430] - Reduce internal diesel injector deposits;

[0431] - Improve fuel economy;

[0432] - Reduce fuel filter deposits;

[0433] - Reduce emissions; and

[0434] -Extended maintenance intervals.

[0435] In addition to the benefits listed above, the additives of the present invention may also provide other benefits. For example, the additives may provide lubricity benefits and / or corrosion inhibition and / or cold flow improvements.

[0436] In some embodiments, combinations of the additives of the present invention with additional additives can provide synergistic improvements in performance.

[0437] For example, the use of an additive of the present invention in combination with a cold flow improver can provide unexpected improvements in detergency and / or cold flow performance compared to the performance of using only one additive alone.

[0438] In some embodiments, use of the additives of the present invention may enable the use of lower treat rates of cold flow improvers.

[0439] For example, the use of an additive of the present invention in combination with a corrosion inhibitor may provide unexpected improvements in detergency and / or corrosion inhibition as compared to the performance of either additive alone.

[0440] In some embodiments, use of the additives of the present invention may enable the use of lower treat rate corrosion inhibitors.

[0441] For example, the use of the additives of the present invention in combination with a lubricity improver can provide unexpected improvements in detergency and / or lubricity compared to the performance of either additive alone.

[0442] In some embodiments, use of the additives of the present invention may enable the use of lower treat rates of lubricity improvers.

[0443] For example, the use of the additives of the present invention in combination with a defoaming additive can provide unexpected improvements in defoaming performance compared to the performance of using only one additive alone.

[0444] In some embodiments, use of the additives of the present invention may enable the use of lower treat rates of antifoam additives.

[0445] In some embodiments, the additives of the present invention may provide "defoam enhancing properties." This means that adding the additives of the present invention to a composition comprising a defoaming additive improves the defoaming properties.

[0446] In some preferred embodiments, the diesel fuel composition of the present invention comprises one or more additional detergents. Preferred are nitrogen-containing detergents.

[0447] The one or more additional detergents may provide a synergistic benefit such that improved performance is observed when using the combination of the additive of the present invention and the nitrogen-containing detergent as compared to using an equivalent amount of either additive alone.

[0448] The combined use of the additives of the present invention and nitrogen-containing detergents can also eliminate deposits and improve the performance of conventional diesel engines.

[0449] In some embodiments, the combination of the additives of the present invention and nitrogen-containing cleaning agents can provide improvements in defoaming performance (defoam enhancement).

[0450] In some embodiments, the combination of the additives of the present invention and nitrogen-containing detergents can provide improvements in lubricity.

[0451] In some embodiments, the combination of the additives of the present invention and nitrogen-containing cleaners can provide improvements in corrosion inhibition performance.

[0452] The improved performance of the second and third aspects of the invention is preferably achieved by eliminating deposits in the engine.

[0453] The additives used in the present invention have been found to be particularly effective in modern diesel engines having high pressure fuel systems.Some features of such engines have been previously described herein.

[0454] Suitably, the present invention can eliminate deposits and / or improve the performance of a diesel engine having a high pressure fuel system. Suitably, the diesel engine has a pressure in excess of 1350 bar (1.35 x 10 8 Pa). Its pressure can be up to 2000 bar (2x10 8 Pa) or higher.

[0455] Two non-limiting examples of such high pressure fuel systems are: a common rail injection system, in which the fuel is compressed by a high pressure pump and supplied to the fuel injection valves via a common rail; and a unit injection system, which integrates 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.

[0456] 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.

[0457] In both systems, the fuel is present in the injector body prior to injection, where it is further heated by the heat of the combustion chamber. The fuel temperature at the injector tip can be as high as 250-350°C.

[0458] 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.

[0459] A common problem in diesel engines is injector fouling, particularly injector body and injector nozzle fouling. Fouling may also occur in the fuel filter. Injector nozzle fouling occurs when the nozzle becomes clogged with deposits from the diesel fuel. Fouling of the fuel filter may be associated with fuel recirculation back into the fuel tank. Deposits also increase as the fuel deteriorates. Deposits may be in the form of carbonaceous coke-like residues, varnish-like, or sticky or gummy residues. The more diesel fuel is heated, especially under pressure, the more unstable it becomes. Therefore, diesel engines with high-pressure fuel systems may experience increased fuel degradation. In recent years, the need to reduce emissions has led to the continuous redesign of injection systems to help meet lower targets. This has resulted in injectors becoming increasingly complex and less tolerant of deposits.

[0460] Injector fouling can be a problem when using any type of diesel fuel. However, some fuels may be particularly susceptible to fouling, or fouling may occur more quickly when using these fuels. For example, fuels containing biodiesel and fuels containing metallic substances may cause increased deposits.

[0461] When an injector becomes clogged or partially clogged, fuel is delivered less efficiently and the fuel mixes poorly with the air. Over time, this can lead to a loss of engine power, increased exhaust emissions and reduced fuel economy.

[0462] Deposits are known to form in the spray passages of injectors, resulting in reduced flow and power losses. The relative impact of deposit buildup becomes more significant as injector nozzle orifice size decreases. Deposits are also known to form at the injector tip. Here they affect the fuel spray pattern and result in reduced combustion efficiency and associated increased emissions and increased fuel consumption.

[0463] In addition to these "external" injector deposits in the nozzle bore and at the injector tip, which can cause reduced flow and power loss, deposits can also form within the injector body, causing further problems. These deposits may be referred to as internal diesel injector deposits (or IDIDs). IDIDs can appear on key moving parts inside the injector. They can impede the movement of these parts, affecting when and how much fuel is injected. Because modern diesel engines operate under very precise conditions, these deposits can have a significant impact on performance.

[0464] IDID can cause a number of problems, including loss of power and reduced fuel economy due to suboptimal fuel metering and combustion. Initially, users may experience cold start problems and / or a rough running engine. These deposits can lead to more serious injector sticking. This occurs when the deposits prevent injector parts from moving and therefore cause the injector to stop working. When multiple or all injectors stick, the engine may fail completely.

[0465] CEC recently introduced its in-house diesel injector deposit test, CEC F-110-16, to differentiate between fuels that differ in their ability to produce IDID in direct injection common rail diesel engines.

[0466] As mentioned above, injector fouling problems may be more likely to occur when using fuel compositions containing metal substances. A variety of metal substances may be present in the fuel composition. This may be due to contamination of the fuel during manufacture, storage, transportation or use, or due to contamination of the fuel additive. Metal substances may also be intentionally added to the fuel. For example, transition metals are sometimes added as fuel-borne catalysts, for example to improve the performance of diesel particulate filters.

[0467] Injector sticking problems may occur when metal or ammonium species (especially sodium species) react with carboxylic acid species in the fuel.

[0468] Sodium contamination of diesel fuel and the resulting formation of carboxylates is believed to be a major cause of injector sticking.

[0469] In some embodiments, the diesel fuel composition used in the present invention comprises sodium and / or calcium. Suitably, they comprise sodium. Sodium and / or calcium are generally present in an amount of 0.01 to 50 ppm, preferably 0.05 to 5 ppm, preferably 0.1 to 2 ppm, for example 0.1 to 1 ppm.

[0470] Other metal-containing substances may also be present as contaminants, for example, by corrosion of metal and metal oxide surfaces by acidic substances present in the fuel or from lubricating oils. During use, fuels (e.g., diesel fuels) 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.

[0471] The presence of metal-containing species may result in fuel filter deposits and / or external injector deposits, including injector tip deposits and / or nozzle deposits.

[0472] 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, a metal-containing fuel-borne catalyst material may be added to aid in the regeneration of a particulate filter. The presence of such a catalyst may also lead to injector deposits when the fuel is used in a diesel engine having a high pressure fuel system.

[0473] Metal-containing contaminants may be in the form of insoluble particulate matter or soluble compounds or complexes, depending on their source. Metal-containing fuel-borne catalysts are usually soluble compounds or complexes or colloidal substances.

[0474] In some embodiments, the diesel fuel may include a metal-containing substance including 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.

[0475] In some embodiments, the diesel fuel may include a metal-containing material including zinc. The zinc may be present in an amount of 0.01 to 50 ppm, preferably 0.05 to 5 ppm, more preferably 0.1 to 1.5 ppm.

[0476] Typically, the total amount of all metal-containing materials in the diesel fuel, expressed as the total weight of metals in the materials, is from 0.1 to 50 ppm, for example from 0.1 to 20 ppm, preferably from 0.1 to 10 ppm, based on the weight of the diesel fuel.

[0477] It is advantageous to provide a diesel fuel composition that prevents or reduces the occurrence of deposits in a diesel engine. In some embodiments, this deposit may include "external" injector deposits, such as deposits in and around the nozzle hole and at the injector tip. In some preferred embodiments, the deposit includes "internal" injector deposits or IDID. This type of fuel composition may be considered to have a "keep clean" function, i.e., they prevent or suppress fouling. It is also desirable to provide a diesel fuel composition that helps to clean up these types of deposits. This fuel composition can remove deposits when burning in a diesel engine, thereby achieving "cleaning" of fouled engines.

[0478] As with the "Stay Clean" feature, "cleaning" of a fouled engine can provide significant advantages. For example, good cleaning may result in increased power and / or improved fuel economy. In addition, removing deposits from the engine, particularly in the injectors, can result in an increase in the time between necessary injector maintenance or replacement, thereby reducing maintenance costs.

[0479] Although deposits in the injectors are a particular problem found in modern diesel engines having high pressure fuel systems for the reasons discussed above, it would still be desirable to provide a diesel fuel composition which would also provide effective cleaning power for older conventional diesel engines so that a single fuel supplied at the pump could be used for all types of engines.

[0480] It is also desirable to have a fuel composition that can reduce fouling of a vehicle's fuel filter. It would be useful to provide a composition that prevents or inhibits the appearance of fuel filter deposits, i.e., provides a "keep clean" function. It would be useful to provide a composition that can remove existing deposits from a fuel filter deposit, i.e., provides a "cleaning" function. Compositions that can provide both functions are particularly useful.

[0481] The method of the present invention is particularly effective for eliminating deposits in modern diesel engines having high pressure fuel systems.

[0482] Such diesel engines can be characterized in a number of ways.

[0483] 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.

[0484] Such engines are typically equipped with a fuel injector having a plurality of holes, each hole having an inlet and an outlet.

[0485] Such engines may be characterized in that the bore is tapered so that the inlet diameter of the injection bore is larger than the outlet diameter.

[0486] Such modern engines may be characterised in that the outlet diameter of the orifices 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.

[0487] Such modern diesel engines may be characterized by a hole in which the inner edge of the inlet is circular.

[0488] Such modern diesel engines may be characterised in that the injector has more than one hole, suitably more than 2 holes, preferably more than 4 holes, for example 6 holes or more.

[0489] Such modern diesel engines may be characterized by operating tip temperatures in excess of 250°C.

[0490] Such modern diesel engines may be characterized in that their fuel injection system provides a fuel pressure of greater than 1350 bar, preferably greater than 1500 bar, more preferably greater than 2000 bar. Preferably, the diesel engine has a fuel injection system comprising a common rail injection system.

[0491] The method of the present invention preferably eliminates deposits in an engine having one or more of the above-described characteristics.

[0492] Use of the present invention preferably improves engine performance by reducing deposits in the engine.

[0493] A second aspect of the invention is preferably directed to a method of improving engine performance by eliminating deposits in the engine. Eliminating deposits may involve reducing or preventing the formation of deposits in the engine compared to when the engine is operated using fuel without additives. This method may be viewed as achieving a "keep clean" performance.

[0494] Eliminating deposits may involve removing existing deposits in the engine. This may be considered to achieve a "cleaning" performance.

[0495] In particularly preferred embodiments, the method of the second aspect and the use of the third aspect of the invention may be used to provide "keep clean" and "clean up" performance.

[0496] As discussed above, deposits may occur at various locations within a diesel engine, such as a modern diesel engine.

[0497] The present invention is particularly useful for preventing or reducing or removing internal deposits in injectors of engines operating at high pressure and temperature, wherein fuel may be recirculated in the injector and the injector comprises a plurality of fine holes through which the fuel is delivered to the engine. The present invention is applicable to engines of heavy vehicles and passenger cars. For example, passenger cars equipped with high speed direct injection (or HSDI) engines may benefit from the present invention.

[0498] The present invention can also improve the performance of modern diesel engines with high pressure fuel systems by controlling external injector deposits (e.g., deposits occurring in the injector nozzle and / or at the injector tip). The ability to control both internal and external injector deposits is a useful advantage of the present invention.

[0499] Suitably, the present invention may reduce or prevent the formation of external injector deposits. Thus, it may provide a "keep clean" performance in relation to external injector deposits.

[0500] Suitably, the present invention can reduce or remove existing external injector deposits. Thus, it can provide a "cleaning" performance in relation to external injector deposits.

[0501] Suitably, the present invention may reduce or prevent the formation of internal diesel injector deposits. Thus, it may provide a "keep clean" performance in relation to internal diesel injector deposits.

[0502] Suitably, the present invention can reduce or remove existing internal diesel injector deposits. Thus, it can provide a "cleaning" performance in relation to internal diesel injector deposits.

[0503] The present invention can also eliminate deposits on vehicle fuel filters. This can include reducing or preventing the formation of deposits ("keep clean" performance) or reducing or removing existing deposits ("cleaning" performance).

[0504] A method by which fuel filter deposit control can be evaluated is described in Example 12.

[0505] According to the present invention, the removal or reduction of IDID will result in improved engine performance.

[0506] Improvements in diesel engine system performance can be measured in a variety of ways. The appropriate method will depend on the type of engine and whether "keep clean" and / or "clean-up" performance is being measured.

[0507] Improvements in "stay clean" performance can be measured by comparison to the base fuel. "Clean-up" performance can be observed by improvements in performance of an already fouled engine.

[0508] The effectiveness of fuel additives is often evaluated using controlled engine tests.

[0509] In Europe, the European Coordinating Committee (an industry body called CEC), which is responsible for developing performance tests for transportation fuels, lubricants and other fluids, has developed tests for additives for modern diesel engines (such as HSDI engines). The CEC F-98-08 test is used to evaluate whether diesel fuel is suitable for use in engines that meet the new EU emission regulations (called "Euro 5" regulations). The test is based on the Peugeot DW10 engine using Euro 5 injectors and is commonly referred to as the DW10B test. The test measures the engine power loss due to deposits on the injectors and is further described in Example 4. Any reference to the DW10B test herein, unless otherwise stated, refers to the method described in Example 4.

[0510] Preferably, use of the fuel composition of the invention results in a reduction in deposits in the DW10B test. For "stay clean" performance, a reduction in the occurrence of deposits is preferably observed.

[0511] For "clean-up" performance, removal of deposits is preferably observed. The DW10B test is used to measure the power loss of modern diesel engines with high pressure fuel systems.

[0512] Suitably, use of the fuel composition of the invention may provide a "keep clean" performance in modern diesel engines, that is to say the formation of deposits in the injectors of these engines may be inhibited or prevented. Preferably, this performance is such that less than 5%, preferably less than 2% power loss is observed after 32 hours, as measured by the DW10B test.

[0513] Suitably, use of the fuel composition of the invention may provide "clean-up" performance in modern diesel engines, that is, the removal of deposits from the injectors of a fouled engine. Preferably, this performance is such that the power of the fouled engine can be restored to within 1% of the level achieved with clean injectors within 16 hours, preferably within 12 hours, more preferably within 8 hours, as measured in the DW10B test.

[0514] In some preferred embodiments, cleaning can also provide a power increase.Thus, a fouled engine can be treated to remove existing deposits and provide additional power gains.

[0515] A cleaned injector may include a new injector or an injector that has been disassembled and physically cleaned (eg, in an ultrasonic bath).

[0516] The combination of the additive of the present invention and a quaternary ammonium salt additive can be particularly effective for improving the performance of modern diesel engines having high pressure fuel systems.

[0517] The CEC has also developed a new test, generally referred to as DW10C, for evaluating the ability of a fuel composition to prevent the formation of IDIDs that lead to injector sticking. This test is described in Example 5. A revised version of this test, which is suitable for measuring cleaning effectiveness, is described in Example 7. Any reference to the DW10C test herein, unless otherwise specified, refers to the method described in Example 5.

[0518] The DW10C test procedure was developed by the CEC as a "keep clean" procedure test and therefore can be used to measure the "keep clean" performance of an engine. However, it has often been revised and used as a clean-up procedure and therefore can also be used to measure the "clean-up" performance of an engine.

[0519] In some embodiments, the present invention provides a "keep clean" performance associated with IDID formation. This performance can be demonstrated by achieving a performance score of at least 7, preferably at least 8, and more preferably at least 9 as measured by the DW10C test.

[0520] In some embodiments, a performance score of at least 9.3, eg, at least 9.4, at least 9.5, at least 9.6, or at least 9.7, can be achieved.

[0521] Very surprisingly, it was found that the additives of the present invention performed exceptionally well in the DW10C test. In some cases, scores of over 9.8, such as over 9.9, were achieved. As described in Example 6, some additives of the present invention can achieve a score of 10 in the DW10C test.

[0522] In some embodiments, the present invention provides a "cleaning" feature associated with an IDID, whereby an existing IDID can be removed. This feature is demonstrated in the examples.

[0523] One of the parameters measured in the DW10C test is the temperature at the exhaust of each cylinder in the engine. The deviation of the exhaust temperature of a single cylinder from its normal steady state temperature range during normal operation indicates the formation of internal deposits in the corresponding fuel injector. Typically, when IDID forms, the exhaust temperatures of multiple cylinders of the engine will deviate from each other, depending on the relative position of each injector (that is, whether it is more open or closed) when injector sticking begins to occur. In the DW10C test, the exhaust temperature deviation can be defined as the temperature difference between the hottest cylinder exhaust and the coldest cylinder exhaust measured at any single time point within a 5 minute idle period after each cold start. The maximum exhaust temperature deviation can be defined as the maximum value of the exhaust temperature deviation that occurs within that same 5 minute idle period.

[0524] Preferably, the method and use of the invention results in a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C. In some cases, a maximum exhaust temperature deviation of less than 10°C may be achieved.

[0525] The additives of the invention have been shown to be particularly effective for eliminating internal diesel injector deposits, even at low treat rates. Thus, the invention may also provide for the use of less than 150 ppm, for example 10 to 120 ppm, of the additives of the invention (particularly the reaction product of itaconic acid or its anhydride with an alkyl or alkenyl alcohol having 4 to 24 carbon atoms) to eliminate IDID, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0526] The present invention can also provide the use of less than 150 ppm (e.g., 10 to 120 ppm) of an additive to eliminate IDID, wherein the additive is itaconic acid or its anhydride and a compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an alkyl or alkenyl group having from 4 to 24 carbon atoms, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0527] The present invention can also provide for the use of less than 150 ppm (e.g., 10 to 120 ppm) of an additive to eliminate IDID, wherein the additive is itaconic acid and a compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an alkyl or alkenyl group having from 4 to 24 carbon atoms, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0528] The present invention can also provide for the use of less than 150 ppm (e.g., 10 to 120 ppm) of an additive to eliminate IDID, wherein the additive is itaconic anhydride and a compound of formula R 1 The polymerization products of OH alcohols, wherein R 1 is an alkyl or alkenyl group having from 4 to 24 carbon atoms, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0529] The present invention may also provide for the use of less than 150 ppm (e.g. 10 to 120 ppm) of an additive which is a polymeric reaction product of itaconic acid or its anhydride and an alcohol selected from 2-ethylhexanol, citronellol and oleyl alcohol to eliminate IDID, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0530] The present invention may also provide for the use of less than 150 ppm (e.g. 10 to 120 ppm) of an additive which is a polymeric reaction product of itaconic acid and an alcohol selected from 2-ethylhexanol, citronellol and oleyl alcohol to eliminate IDID, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0531] The present invention may also provide for the use of less than 150 ppm (e.g. 10 to 120 ppm) of an additive which is a polymeric reaction product of itaconic anhydride and an alcohol selected from 2-ethylhexanol, citronellol and oleyl alcohol to eliminate IDID, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0532] The present invention may also provide for the elimination of IDID using less than 150 ppm (e.g., 10 to 120 ppm) of an additive which is a polymerization reaction product of itaconic acid or its anhydride and an alcohol selected from 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol and 2-decyl-1-tetradecanol and isotridecanol, for example as evidenced by a maximum exhaust temperature deviation of less than 30°C, preferably less than 20°C, suitably less than 15°C in the DW10C test.

[0533] The present invention may also provide for the elimination of IDID using less than 150 ppm (e.g., 10 to 120 ppm) of an additive which is a polymerization reaction product of itaconic acid and an alcohol selected from 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol and 2-decyl-1-tetradecanol and isotridecanol, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0534] The present invention may also provide for the elimination of IDID using less than 150 ppm (e.g., 10 to 120 ppm) of an additive which is a polymerization reaction product of itaconic anhydride and an alcohol selected from 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol and 2-decyl-1-tetradecanol and isotridecanol, for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0535] The present invention can also provide the use of less than 150 ppm (e.g., 10 to 120 ppm) of an additive to eliminate IDID, wherein the additive is itaconic acid or its anhydride and a compound of the formula H-(OR 2 ) m -OR 1 The polymerization products of alcohols wherein R 2 is an optionally substituted alkylene group, R 1 is a C4 to C30 alkyl or alkenyl group, m is not 0 and the additive of the invention is prepared from an alkyl or alkenyl ether of a polyol (e.g. an ether of polyethylene glycol, polypropylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol or tripropylene glycol), for example as evidenced by a maximum exhaust temperature deviation in the DW10C test of less than 30°C, preferably less than 20°C, suitably less than 15°C.

[0536] The present invention may also provide for elimination of IDID using less than 150 ppm (e.g. 10 to 120 ppm) of an additive which is a polymerization reaction product of itaconic acid or its anhydride and an alcohol selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol and glycerol, for example as evidenced by a maximum exhaust temperature deviation of less than 30°C, preferably less than 20°C, suitably less than 15°C in the DW10C test.

[0537] The diesel fuel composition of the present invention may also provide improved performance when used with conventional diesel engines. Preferably, improved performance is achieved when the diesel fuel composition is used in a modern diesel engine having a high pressure fuel system and when the composition is used in a conventional diesel engine. This is important because it allows a single fuel to be provided that can be used for both new engines and older vehicles.

[0538] For older engines, the XUD9 test can be used to measure the improvement in performance. This test is described in relation to Example 8.

[0539] Suitably, use of the fuel composition of the invention may provide a "keep clean" performance in conventional diesel engines, that is to say may inhibit or prevent the formation of deposits on the injectors of these engines. Preferably, this performance is such that less than 50%, preferably less than 30% flow loss is observed after 10 hours, as measured by the XUD-9 test.

[0540] Suitably, the use of the fuel composition of the present invention can provide "cleaning" performance in conventional diesel engines, i.e., can remove deposits on the injectors of fouled engines. Preferably, this performance is such that the flow loss of the fouled engine can be reduced by 10% or more within 10 hours, as measured in the XUD-9 test.

[0541] The benefits provided by the present invention mean that the engine requires less frequent servicing, resulting in cost savings and increased maintenance intervals.

[0542] In a preferred embodiment, the present invention provides the use of a combination of a polymer additive of formula (I) and a quaternary ammonium salt additive for improving the performance of a conventional diesel engine as measured in the XUD-9 test.

[0543] Preferably, the present invention provides itaconic anhydride and formula R 1 Use of a combination of a polymerization product of an alcohol containing 1,2-dihydroxy- ... 1 OH in R 1 is an alkyl or alkenyl group having 4 to 24 carbon atoms, wherein the quaternary ammonium salt additive (ia) is a quaternary ammonium reaction product of a hydrocarbyl-substituted succinic acid-derived acylating agent and a compound capable of reacting with the acylating agent and comprising a tertiary amine group.

[0544] In a preferred embodiment, the present invention may involve itaconic anhydride and formula R 1 A combination of a polymerization product of an alcohol containing OH and a quaternary ammonium salt additive (ia), wherein R 1 is an alkyl or alkenyl group having 4 to 24 carbon atoms, preferably wherein the polymer comprises 6 to 150, preferably 8 to 120 monomer units, and the quaternary ammonium salt additive (ia) is formed by reacting methyl salicylate or dimethyl oxalate with a reaction product of polyisobutylene-substituted succinic anhydride and dimethylaminopropylamine having a PIB molecular weight of 700 to 1300.

[0545] The invention can improve the performance of gasoline engines.

[0546] The gasoline compositions of the present invention suitably achieve good control of deposits in spark ignition gasoline engines.They can provide deposit control for port fuel injection (PFI) gasoline engines.

[0547] Excellent deposit control is achieved even in the demanding environment of direct injection spark ignition gasoline engines.

[0548] Such deposit control may result in significant reductions in maintenance costs and / or increased power and / or improved fuel economy.

[0549] A second aspect of the invention may provide a method of improving performance by controlling deposits in a spark ignition engine.Preferably, the engine is a direct injection spark ignition gasoline engine.

[0550] The performance improvements of the second and third aspects of the present invention may relate to improving the efficiency of a direct injection spark ignition gasoline engine.

[0551] The performance improvements of the second and third aspects of the invention in a direct injection spark ignition gasoline engine may provide one or more of the following:-

[0552] Improve fuel economy

[0553] Reduced maintenance

[0554] Reduce the frequency of maintenance or replacement of injectors

[0555] Improved driving performance

[0556] Increase power

[0557] Improve acceleration performance

[0558] Any feature of the invention may be combined with any other feature as appropriate.

[0559] The invention will now be further described with reference to the following non-limiting examples. In the following examples, the treatment rate values ​​given in parts per million (ppm) represent the amount of active agent, rather than the amount of formulation added and containing the active agent. All parts per million are by weight.

[0560] General Procedure

[0561] The acid value was determined by non-aqueous titration using lithium methoxide (LiOMe).

[0562] Embodiment 1:

[0563] To a 1 L reaction vessel filled with 2-ethylhexanol (250 g, 1.918 moles) was added toluene (215.7 g) and heated to 90°C. To the stirred liquid was added itaconic acid (250 g, 1.921 moles) and p-toluenesulfonic acid (3.31 g). The reaction was heated to 120°C while removing water by distillation over 7 hours. The product was cooled to room temperature and unreacted itaconic acid and p-toluenesulfonic acid were removed by filtration and water washing. Toluene was removed on a rotary evaporator to give a yellow / orange liquid (2-ethylhexyl itaconate, 412.9 g)

[0564] Embodiment 2:

[0565] Additive A, a polymer additive of the present invention, is prepared as follows:

[0566] Cyclohexane (51.43 g) was added to a 250 ml reactor containing 2-ethylhexyl itaconate (120 g), and the reactor contents were sparged with nitrogen for 1 hour while heating to 80° C. Trigonox 25-C75 (0.685 g, 0.5 wt %, tert-butyl peroxypivalate) was added and mixed at 80° C. for 1 hour, then more Trigonox 25-C75 (0.685 g) was added and heated at 80° C. for another 3 hours. The cyclohexane was removed on a rotary evaporator, and Aromatic 150 (69.7 g) was added to give a clear amber viscous liquid (184.4 g, Mw 10932, acid number 2.4 mmol H+ / g).

[0567] Embodiment 3:

[0568] Additive B, a quaternary ammonium salt additive, is prepared as follows:

[0569] 700 g (0.7 mol) of polyisobutylene (M n 1000) is loaded into the jacketed reactor equipped with nitrogen flushing of overhead stirrer. Starting material is heated to 120 ℃ and nitrogen inertization is repeated under stirring. Reaction temperature is raised to 190 ℃, and maleic anhydride (82.4g, 0.84mol, 1.2 equivalents) is loaded in 1 hour. After temperature is maintained at 190 ℃ for another 1 hour, temperature is raised to 200-208 ℃ and kept in this range for 8 hours. Then vacuum (<30mbar) is applied for 2.5 hours, while maintaining reaction temperature, which reduces the content of residual maleic anhydride to ≤0.05 weight %. Reaction mass is cooled to ≤80 ℃, then discharged from reactor.

[0570] The resulting PIBSA was charged into a nitrogen flushed jacketed reactor equipped with an overhead stirrer and heated to 120°C. 3-(Dimethylamino)propylamine (DMAPA) (1 equivalent relative to the anhydride groups) was slowly added, maintaining the reaction temperature between 120-130°C. After stirring at 120°C for another hour, the reaction temperature was raised to 140°C and maintained for 3 hours while distilling water. Methyl salicylate (2.1 equivalents relative to the anhydride groups) was added in one portion and heating was continued at 140°C for 10 hours. The reaction mass was diluted with Aromatic 150 and then discharged from the reactor.

[0571] Embodiment 4:

[0572] Diesel fuel compositions were prepared by dosing the additive into an aliquot taken from the same batch of RF06 base fuel and contained 1 ppm zinc (as zinc neodecanoate).

[0573] Table 1 below shows the specifications of RF06 base fuel.

[0574] Table 1.

[0575]

[0576] The preparation of the composition is shown in Table 2:

[0577] Table 2.

[0578]

[0579] Embodiment 5:

[0580] The performance of the fuel composition of the present invention in a modern diesel engine with a high pressure fuel system was tested according to the CEC F-98-08 DW10 method. This is referred to herein as the DW10B test.

[0581] The engine used for injector fouling test is PSA DW10BTED4. In summary, the characteristics of this engine are:

[0582] Design: Inline four-cylinder, overhead camshaft, turbocharged with EGR

[0583] Displacement: 1998cm 3

[0584] Combustion chamber: Four valves, piston bowl, wall-guided direct injection

[0585] Power: 100kW@4000rpm

[0586] Torque: 320Nm@2000rpm

[0587] Injection system: Common rail with piezo-electronically controlled 6-hole injectors.

[0588] Maximum pressure: 1600bar(1.6x10 8 Pa). Proprietary design of SIEMENS VDO

[0589] Emission control: Complies with Euro IV limits when used in conjunction with exhaust aftertreatment system (DPF)

[0590] The engine was chosen as a representative design for a modern European high-speed direct injection diesel engine that is able to comply with current and future European emissions requirements. The common rail injection system uses a high-efficiency nozzle design with rounded inlet edges and tapered spray holes for optimal hydraulic flow. This type of nozzle, combined with high fuel pressures, results in improved combustion efficiency, reduced noise and reduced fuel consumption, but is sensitive to factors that can interfere with fuel flow, such as deposits forming in the spray holes. The presence of these deposits can lead to a significant loss of engine power and an increase in raw emissions.

[0591] The testing was conducted using a future injector design that is representative of expected Euro V injector technology.

[0592] Before commencing fouling testing, it was necessary to consider establishing a reliable baseline of injector conditions, therefore, a sixteen hour run-in schedule for the test injectors was specified using a non-fouling reference fuel.

[0593] Complete details of the CEC F-98-08 test method are available from the CEC. The coking cycle is summarized below.

[0594] 7. Perform a warm-up cycle (12 minutes) according to the following scheme:

[0595] step Duration (minutes) Engine speed (rpm) Torque(Nm) 1 2 Idle <5 2 3 2000 50 3 4 3500 75 4 3 4000 100

[0596] 2. The engine is run for 8 hours, including 8 repetitions of the following cycle

[0597] *For expected ranges, see CEC Method CEC-F-98-08

[0598] 3. Cool down to idle speed within 60 seconds and idle for 10 seconds

[0599] 4.4 hours heat preservation time

[0600] The standard CEC F-98-08 test method includes 32 hours of engine operation, corresponding to 4 repetitions of steps 1-3 above, and 3 repetitions of step 4. The total test time of 56 hours does not include warm-up and cool-down.

[0601] Table 3 shows the results of composition 1 and composition 2 when tested according to the above method:

[0602] Table 3.

[0603] Tested composition Power loss after 32 hours (%) 1 5.21 2 0.19

[0604] Embodiment 6:

[0605] Diesel Fuel Composition 3 was tested according to the CEC F-98-08DW10B test method described in Example 5, and modified to measure cleanup performance as described below.

[0606] The first 32 hour cycle was run using new injectors and RF-06 base fuel to which 1 ppm Zn (as neodecanoate) was added. This resulted in a power loss level of 5.1% due to injector fouling.

[0607] A second 32 hour cycle was then run as a "clean-up" phase. The dirty injectors from the first phase remained in the engine and the fuel was changed to RF-06 base fuel with 1 ppm Zn (as neodecanoate) added to it and the test additive. This restored the power to a loss of 1.5% compared to the power gained with the clean injectors.

[0608] Embodiment 7:

[0609] Diesel Fuel Composition 7 was tested according to the CEC F-98-08DW10B test method described in Example 5, and modified to measure cleanup performance as described below.

[0610] The first 32 hour cycle was run using new injectors and RF-06 base fuel to which 1 ppm Zn (as neodecanoate) was added. This resulted in a power loss level of 5.8% due to injector fouling.

[0611] A second 32 hour cycle was then run as a "clean-up" phase. The dirty injectors from phase one remained in the engine and the fuel was changed to RF-06 base fuel with 1 ppm Zn (as neodecanoate) added to it and the test additive. This restored power to a 0.3% gain over the power obtained with the clean injectors.

[0612] Embodiment 8:

[0613] The ability of the additives of the present invention to remove 'internal diesel injector deposits' (IDID) was measured according to test method CEC F-110-16 available from the Council for European Harmonisation. The test employs a PSA DW10C engine.

[0614] The engine features are as follows:

[0615]

[0616] The test fuel (RF06) was dosed with 0.5 mg / kg Na in the form of sodium naphthenate + 10 mg / kg dodecylsuccinic acid (DDSA).

[0617] The test procedure consisted of a main operating cycle followed by a soak period and then a cold start.

[0618] The main operating cycle consists of two speed and load set points, repeated for 6 hours, as shown below.

[0619] step Speed ​​(rpm) Torque(Nm) Duration(s) 1 3750 280 1470 1-Slope → 2 - - 30 2 1000 10 270 2-Slope → 1 - - 30

[0620] A ramp time of 30 s was included in the duration of each step.

[0621]

[0622] Each cycle is repeated 6 times so that the entire main operation phase lasts 6 hours

[0623] During the main run, observe and record parameters including accelerator pedal position, ECU fault codes, injector balance factors, and engine stalls.

[0624] The engine was then held at ambient temperature for 8 hours.

[0625] After the warm-up period, the engine is restarted. The starter runs for 5 seconds; if the engine fails to start, the engine is left idle for 60 seconds before trying to start again. A maximum of 5 attempts are allowed.

[0626] If the engine is started, allow the engine to idle for 5 minutes. Monitor the individual exhaust temperatures and record the maximum temperature difference. An increase in exhaust temperature variation between cylinders is a good indication that the injectors are suffering from IDID. This is causing them to open slowly or remain open too long.

[0627] In the example below, all exhaust temperature deviations are less than 30°C, indicating no sticking caused by the IDID.

[0628] Maximum temperature deviation (℃) 13.7

[0629]

[0630] The full test included six cold starts (although zero-hour cold starts do not form part of the performance score) and five six-hour main operating cycles, totaling 30 hours of engine run time.

[0631] The recorded data is entered into a performance score sheet. This generates a score for the test. The highest score of 10 indicates no issues with the operation or operability of the engine for the duration of the test.

[0632] The following are examples:

[0633]

[0634] Composition 1 and Composition 2 were tested according to this method, and the results are shown in Table 4:

[0635] Table 4.

[0636] Tested composition Final performance score 1 8 2 10

[0637] Embodiment 9:

[0638] The ability of the additives of the present invention to clean IDID can be evaluated according to a modified version of the DW10C test described in Example 7.

[0639] The developed internal cleaning method first runs the engine with a reference diesel (RF06) dosing with 0.5mg / kg Na + 10mg / Kg DDSA until an exhaust temperature deviation (Delta) > 50°C is observed at cold start. This occurs repeatedly in the third cold start after the second main run, with a total engine run time of 12 hours.

[0640] Once the exhaust temperature delta increase was observed, the engine fuel supply was switched to reference diesel dosed with 0.5 mg / kg Na (as sodium naphthenate) + 10 mg / kg DDSA + candidate sample. The fuel was flushed into the engine and the next main run was started.

[0641] As testing continues, the ability of the candidate additive to prevent any further increase in deposits or to remove deposits can then be determined.

[0642] Composition 4 was tested in this way. After the soiling phase, a performance score of 8.4 was obtained. This value increased to 10 points when composition 4 was used.

[0643] Embodiment 10:

[0644] The effectiveness of the additives of the present invention in older conventional diesel engine types can be evaluated using a standard industry test - CEC Test Method No. CEC F-23-A-01.

[0645] This test measures injector nozzle coking using a Peugeot XUD9 A / L engine and provides a means of differentiating between fuels with different propensities to injector nozzle coking. Nozzle coking is caused by the formation of carbon deposits between the injector needle and the needle seat. The deposition of carbon deposits is caused by the exposure of the injector needle and seat to the combustion gases and can cause undesirable changes in engine performance.

[0646] The Peugeot XUD9 A / L engine is a 4-cylinder indirect injection diesel engine with a swept volume of 1.9 litres, obtained from Peugeot Citroen Motors built specifically for the CEC PF023 method.

[0647] The test engine was equipped with cleaned injectors, using uncrushed injector needles. The airflow at various needle lift positions was measured on a flow meter before testing. The engine was run under cyclic conditions for a period of 10 hours.

[0648] stage Time (seconds) Speed ​​(rpm) Torque(Nm) 1 30 1200±30 10±2 2 60 3000±30 50±2 3 60 1300±30 35±2 4 120 1850±30 50±2

[0649] The propensity of a fuel to promote deposit formation on a fuel injector is determined by measuring the injector nozzle airflow again at the end of the test and comparing these values ​​to those before the test. The results are expressed as a percentage reduction in airflow for all nozzles at each needle lift position. The average of the airflow reduction at 0.1 mm needle lift for all four nozzles is taken as the injector coking level for a given fuel.

[0650] Compositions 5 and 6 were tested and the results are shown in Table 5:

[0651] Table 5.

[0652] Tested composition Flow loss (%) 1 75.2 5 -0.1 6 1.7

[0653] For composition 5, a significant increase in flow rate of 0.1% was observed.

[0654] Embodiment 11:

[0655] The ability of composition 7 to remove deposits in a XUD-9 engine was measured by first performing the test described in Example 9 using a base fuel, then adding composition 3 to a dirty engine and repeating the test. Flow loss was reduced from 72% after the dirty stage to 35.5% after the addition of composition 7.

[0656] Embodiment 12:

[0657] The ability of the additives of the present invention to reduce fuel filter deposits was evaluated according to the following procedure:

[0658] Sodium dodecenylsuccinate was produced by heating a 2.5 wt% solution of sodium 2-ethylhexanoate and dodecenylsuccinic acid in RF06 fuel for 3 hours at 150° C. This was added to 650 g of RF06 reference fuel in an amount to achieve the desired concentration of sodium dodecenylsuccinate.

[0659] The additive of the present invention is dosed into the fuel sample at the desired treat rate.

[0660] The sample was then heated at 50°C overnight (approximately 16 hours).

[0661] The fuel is filtered through a 10 micron fuel filter with a 25mm diameter and a 600 mbar vacuum is used to pull the fuel through the filter.

[0662] The flow rate through the filter is determined by measuring the mass of fuel remaining in the original sample container over time.

[0663] Embodiment 13:

[0664] The method described in Example 12 was used to measure the flow rate of the compositions of Table 6 through a 10 micron fuel filter.

[0665] Table 6.

[0666]

[0667]

[0668] The results are shown in Table 7:

[0669] Table 7.

[0670]

[0671] Embodiment 14:

[0672] Additive C, another additive of the present invention, is prepared as follows: Step 1 - Esterification to 2-ethylhexyl itaconate

[0673] A clean 1 L oil jacketed reactor with an overhead stirrer was purged with nitrogen and charged with 2-ethylhexanol (300.91 g, 2.31 moles), Aromatic 150 (236.32 g) and stirred. Itaconic acid (250.51 g, 1.925 moles) and p-toluenesulfonic acid (1.54 g, 0.2 wt%) were added and the reaction was heated to 120° C. Water was distilled from the reaction as an azeotrope with A150 over 4 hours.

[0674] The reaction mixture was heated to 80°C, washed with water (2 x 150 ml), stirred for 10 minutes, allowed to separate for 1 hour, and the lower aqueous layer was drained. Residual water was removed under vacuum at 80°C within 1 hour.

[0675] Step 2-Polymerization to 2-ethylhexyl polyitaconate

[0676] The reaction mixture from step 1 was heated to 72°C and purged with nitrogen. Trigonox 25-C75 (6 x 2 g) was added over 5 hours, once every hour. The reaction was heated for an additional 6 hours and then diluted with more Aromatic A150 (207.42 g) to give a light amber viscous clear liquid (836.29 g).

[0677] Embodiment 15:

[0678] The prepared additive composition comprises the following components:

[0679] Table 8.

[0680] additive Composition I (wt% active) Composition II (wt% active) B 15.2 15.2 C 15.9 15.9 Defogging agent 2.7 2.7 Silicone-based defoaming additives 1.7 0.85 Aromatic solvents 21.4 22.5 2-Ethylhexanol 20 20 Other solvents, etc. Up to 100 Up to 100

[0681] A diesel fuel composition was prepared by adding the additive composition of Table 8 to a R-06B0 diesel base fuel as detailed in Table 9.

[0682] Table 9.

[0683]

[0684]

[0685] Embodiment 16:

[0686] The defoaming properties of the compositions in Table 9 were tested using an internal revision of the BNPé test procedure (Nf M 07-075). The results are shown in Table 10:

[0687] Table 10.

[0688]

[0689] Embodiment 17:

[0690] Diesel fuel compositions were prepared by dosing the additives into Coryton B0 fuel as detailed in Table 11.

[0691] Additive D is a commercially available lubricity improver which is the reaction product of a C16 to C18 alkenyl substituted succinic acid and at least 2 molar equivalents of ethylene glycol.

[0692] Additive E is glycerol monooleate.

[0693] Table 11.

[0694]

[0695] The lubricity of compositions 18 to 20 was evaluated using a high frequency reciprocating rig (HFRR) following the standard procedure specified in IP 450.

[0696] The results are shown in Table 12:

[0697] Table 12.

[0698] Composition Wear marks(μm) Basic fuel 630 18 450 19 410 20 270 21 290 22 460 23 270

[0699] Embodiment 18:

[0700] A diesel fuel composition was prepared comprising:

[0701] Table 13.

[0702] Composition Additive C Additive F 24 16.5 25 27.5 295

[0703] Additive F is a multi-component additive package that contains a quaternary ammonium cleaner, a Mannich cleaner, and a defoaming additive. It does not contain a corrosion inhibitor.

[0704] The corrosion inhibition performance of the composition of Table 13 was tested according to the standard test method ASTM D665. The results are shown in Table 14:

[0705] Table 14.

[0706] Composition corrosion,% corrosion,% NACE score (TM0172-2001) 24 <0.1 1 B+ 25 0 0 A

Claims

1. A fuel composition comprising as an additive a polymer of formula (I): wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

2. A method for improving engine performance, the method comprising burning in an engine a fuel composition comprising as an additive a polymer of formula (I): wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

3. Use of a polymer of formula (I) as an additive to a fuel composition for improving the performance of an engine burning said fuel composition: wherein n is at least 6, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

4. A method for preparing an additive of formula (I): The method comprises the following steps: (ii) reacting a dicarboxylic acid of formula (II) or its anhydride with an alcohol: and (ii) the reaction product obtained in the polymerization step (i); wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

5. A method for preparing a fuel composition, the method comprising quantitatively adding a polymer additive of formula (I) to a fuel: wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

6. The method according to claim 5, comprising the steps of: (i) reacting a dicarboxylic acid of formula (II) or its anhydride with an alcohol: (ii) polymerizing the reaction product defined in step (ii) to provide an additive of formula (I); (I); and (iii) dosing the additive into the fuel; wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

7. The method according to claim 4 or claim 6, wherein the dicarboxylic acid or its anhydride is selected from itaconic acid, itaconic anhydride, 2-methyleneglutaric acid, 2-methyleneglutaric anhydride, 2-methyleneadipic acid, 2-methyleneadipic anhydride and isomers and / or mixtures thereof.

8. The method of claim 4, 6 or 7, wherein the alcohol has the formula H-(OR 2 ) m -OR 1 And selected from: - short-chain alcohols having 1 to 3 carbon atoms; - short-chain polyols having 2 or 3 carbon atoms; -Formula CH3(CH2) a OH-alkanol or its isomers, wherein a is 4 to 23; - a branched or cyclic alkyl alcohol, wherein m is 0 and R 1 having 6 to 24 carbon atoms; -alkenyl alcohol, wherein n is 0 and R 1 having 6 to 24 carbon atoms; - glycol ethers, wherein m is not 0; and - A mixture thereof.

9. The method according to claim 4, 6, 7 or 8, wherein the alcohol is selected from the group consisting of hexyl alcohol, octanol, nonanol, decanol, dodecanol, tetradecanol, cetyl alcohol, stearyl alcohol, 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol, isotridecanol, cyclohexanol, cyclooctanol and benzyl alcohol.

10. An additive composition comprising: a polymer of formula (I): wherein n is at least 4, x may be 0 or a positive integer, y may be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen; one or more additional cleaning agents, preferably one or more additional nitrogen-containing cleaning agents; and a diluent or carrier.

11. The composition, method or use according to any one of the preceding claims, wherein n is from 10 to 200.

12. The composition, method or use according to any one of the preceding claims, wherein x is 0 and y is 1.

13. A composition, method or use according to any one of the preceding claims, wherein each R is hydrogen or (OR 2 ) m -OR 1 , where R 2 is an optionally substituted alkylene or arylene group; R 1 is hydrogen or an optionally substituted hydrocarbon group; and m is 0 or a positive integer; provided that when R 1 When it is hydrogen, m is not 0.

14. A composition, method or use according to any preceding claim, wherein each R is hydrogen or an unsubstituted linear or branched alkyl or alkenyl group having from 4 to 50 carbon atoms, preferably from 6 to 30 carbon atoms.

15. A composition, method or use according to any preceding claim, wherein 30% to 70% of all R groups in the additive of formula (I) are not hydrogen, preferably 40% to 60%, more preferably 45% to 55% are not hydrogen.

16. A composition, method or use according to any one of claims 1 to 14, wherein at least 90% of all R groups in the additive of formula (I) are not hydrogen, preferably at least 95%, more preferably at least 99% are not hydrogen.

17. A composition, method or use according to any preceding claim wherein the additive is present in the fuel in an amount of from 10 to 200 ppm.

18. A composition, method or use according to any preceding claim, wherein the additive of formula (I) is a polymerisation reaction product of itaconic acid or its anhydride and 2-ethylhexanol, wherein the polymer has a weight average molecular weight of from 2000 to 50000, preferably from 4000 to 30000, more preferably from 5000 to 20000, for example from 6000 to 15000, suitably from 8000 to 12000.

19. A composition, method or use according to any one of claims 1 to 3 or 5 to 18, wherein the fuel composition is a diesel fuel composition.

20. A composition, method or use according to claim 19, wherein the diesel fuel composition comprises one or more additional detergents 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.

21. A composition, method or use according to claim 20, wherein the diesel fuel composition comprises a quaternary ammonium salt additive (ia) which is the quaternization reaction product of a hydrocarbyl-substituted succinic acid derived acylating agent and a compound capable of reacting with the acylating agent and comprising a tertiary amine group; wherein each hydrocarbyl-substituted succinic acid derived acylating agent molecule comprises on average at least 1.2 succinic acid moieties.

22. A composition, method or use according to claim 20 or claim 21, wherein the weight ratio of the polymer additive of formula (I) to the nitrogen-containing detergent is from 10:1 to 1:10, preferably from 5:1 to 1:5, preferably from 2:1 to 1:

2.

23. A method or use according to any one of claims 2, 3 or 8 to 22, wherein the engine is a diesel engine.

24. A method or use according to any one of claims 2, 3 or 8 to 23 providing an improvement in the performance of a modern diesel engine having a high pressure fuel system and / or providing an improvement in the performance of a conventional diesel engine.

25. A method or use according to any one of claims 2, 3 or 8 to 23 wherein the improved performance is achieved by eliminating deposits in the engine.

26. The method of claim 25 which eliminates internal diesel injector deposits.

27. A method according to claim 25 or claim 26 which eliminates external diesel injector deposits including injector nozzle deposits and injector tip deposits.

28. A method according to any one of claims 25 to 27 which eliminates fuel filter deposits.

29. The method or use according to any one of claims 25 to 28, which achieves a "keep clean" performance.

30. The method or use according to any one of claims 25 to 29, which achieves a "clean-up" performance.

31. Use of a polymer of formula (I) for improving the lubricity of a diesel fuel composition: wherein n is at least 4, x may be 0 or a positive integer, y may be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbon group, provided that at least 10% of all R groups are not hydrogen; the diesel fuel composition comprises a lubricity improver and optionally one or more nitrogen-containing detergents, preferably a quaternary ammonium salt additive.

32. Use of a polymer of formula (I) in combination with a corrosion inhibitor for improving corrosion inhibition performance compared to the performance of using only one additive: wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

33. Use of a polymer of formula (I) for improving the defoaming properties of a diesel fuel composition comprising a defoaming additive: wherein n is at least 4, x can be 0 or a positive integer, y can be 0 or a positive integer, and each R is independently hydrogen or an optionally substituted hydrocarbyl group, provided that at least 10% of all R groups are not hydrogen.

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