EP2814917B1 - Additives for improving the resistance to wear and to lacquering of diesel or biodiesel fuels - Google Patents

Description

The present invention relates to the use of additives to improve the resistance to lacquering of fuels of the (bio) diesel type of superior quality.

The sulfur content of diesel (B0) or biodiesel (Bx) fuels has been reduced in many countries for environmental reasons, in particular to reduce SO ₂ emissions. For example, in Europe, the maximum sulfur content of road diesel fuels is currently 10 ppm by mass.

The processes for preparing low-sulfur diesel or diesel fuel bases, for example hydrotreatment processes, in addition to reducing the sulfur content, also reduce the content of these diesel fuel bases in polycyclic aromatic compounds and in polar compounds. . However, it is known that diesel fuels or diesel with low (less than 100 ppmm) or even very low sulfur content have a reduced ability to lubricate the injection system of the engine, which means that for example the injection pump of engine fuel may fail early in the life of the engine, such as failure in high pressure fuel injection systems, such as high pressure rotary distributors, in-line pumps , combined pumps, with injectors and injectors.

Lubricants and / or antiwear additives for fuel oils have been described in EP 680 506 ; these additives include an ester of a carboxylic acid and an alcohol, in which the acid has from 2 to 50 carbon atoms, and the alcohol has one or more atoms; one of the preferred additives is glycerol monooleate (GMO).

1. a) un ester obtenu par réaction d'un acide monocarboxylique insaturé et d'un alcool polyhydroxylé
2. b) un ester obtenu par réaction d'un acide monocarboxylique insaturé et d'un alcool polyhydroxylé ayant au moins 3 groupes hydroxy,

les esters a) et b) étant différents. Outre leurs propriétés lubrifiantes, ces mélanges d'esters présentent une filtrabilité (mesurée selon la norme IP 387) particulièrement bonne ; les mélanges d'esters préférés sont les mélanges comprenant majoritairement du monooléate de glycérol et de monolinoléate de glycérol, de préférence en proportions sensiblement égales.In EP 839174 are described lubricant additives comprising:

1. a) an ester obtained by reaction of an unsaturated monocarboxylic acid and a polyhydroxy alcohol
2. b) an ester obtained by reaction of an unsaturated monocarboxylic acid and a polyhydric alcohol having at least 3 hydroxy groups,

the esters a) and b) being different. In addition to their lubricating properties, these mixtures of esters have a particularly good filterability (measured according to standard IP 387); the preferred ester mixtures are the mixtures mainly comprising glycerol monooleate and glycerol monolinoleate, preferably in substantially equal proportions.

In EP 915,944 are described anti-wear additives for diesel fuels with low sulfur content constituted by a combination of at least one aliphatic monocarboxylic hydrocarbon, saturated or unsaturated, of linear chain between 12 and 24 carbon atoms and at least one hydrocarbon compound polycyclic chosen from the group consisting of natural resin acids, and carboxylate derivatives of amines, esters and nitriles of these acids. These additives can for example be derived from tall oil (in English "tall oil"). In US 2012/0010112 A1 , additives are described to improve the resistance to lacquering of diesel fuels.

However, diesel or diesel fuels and in particular higher quality fuels additivated with these anti-wear additives have sometimes been found to have unsatisfactory lacquering resistance properties.

Diesel fuels sold must comply with national or supranational specifications (for example the EN 590 standard for diesel fuels in the EU). For commercial fuels, there is no legal obligation concerning the incorporation of additives (chemical compounds incorporated into fuels to improve their properties, for example additives improving cold resistance); oil companies, distributors are free to add or not additives to their fuels. From a commercial point of view, in the field From the distribution of fuels, a distinction is made between “first price” fuels, with little or no additives, and higher quality fuels in which one or more additives are incorporated to improve their performance (beyond regulatory performance). For the purposes of the present invention, the term “high quality fuel of the diesel or biodiesel type” means any diesel fuel or biodiesel additive with at least 50 ppm by mass of at least one compound chosen from deposit reducers, detergents, dispersants.

A distinction is made between diesel fuels of type B0, which do not contain an oxygenated compound, and biodiesel fuels of type Bx which contain x% (v / v) of vegetable oil esters or fatty acids, most often methyl esters. (EMHV or EMAG)
It has been found that certain higher quality diesel or biodiesel fuels are sometimes the cause of deposits on the injector needles of diesel engine injection systems, in particular those of the Euro 3 to Euro 6 type.

This deposit phenomenon is also known under the English term lacquering which will be used in the description which follows or under the English acronym IDID (internai diesel injector deposits). Within the meaning of the present invention, the phenomenon of lacquering does not relate to deposits external to the injection system relating to coking (coking in English) or clogging of injection nozzles (nozzle coking or fouling) as simulated for example by the standard engine test CEC F098-08 DW10B, in particular when the fuel tested is contaminated with metallic zinc.

The lacquering phenomenon can be localized on the end of the injector needles, both on the head and on the body of the needles of the fuel injection system but also in the whole control system of the lifting of needles (valves) of the injection system, for the engines of vehicles running on diesel or biodiesel fuel, and in particular for higher quality (bio) diesel fuels. This lacquering phenomenon can ultimately generate a loss of flow of injected fuel and therefore a loss of engine power.

1. 1. des dépôts plutôt blanchâtres et pulvérulents ; par analyse, on constate que ces dépôts consistent essentiellement en des savons de sodium (carboxylate de sodium, par exemple) et/ou de calcium (dépôts de type 1) ;
2. 2. des dépôts organiques assimilables à des vernis colorés localisés sur le corps de l'aiguille (dépôts de type 2).

There are generally 2 types of lacquering type deposits:

1. 1. rather whitish and powdery deposits; by analysis, it can be seen that these deposits consist essentially of sodium soaps (sodium carboxylate, for example) and / or of calcium (type 1 deposits);
2. 2. organic deposits similar to colored varnishes located on the body of the needle (type 2 deposits).

• les catalyseurs de transestérification des huiles végétales pour la production des esters de type esters (m)éthyliques d'acides gras tel que le méthanoate de sodium ;
• une autre source possible de sodium peut provenir des inhibiteurs de corrosion utilisés pour le transport de produits pétroliers dans certains tuyaux (en anglais « pipes »), tel que le nitrite de sodium ;
• enfin des pollutions exogènes accidentelles, via l'eau ou l'air par exemple, peuvent contribuer à introduire du sodium dans les carburants (le sodium étant un élément très répandu).

With regard to type 1 deposits, the sources of sodium in biodiesel fuels of type Bx can be multiple:

• vegetable oil transesterification catalysts for the production of esters of the (m) ethyl ester type of fatty acids such as sodium methanoate;
• another possible source of sodium can come from corrosion inhibitors used for the transport of petroleum products in certain pipes (in English "pipes"), such as sodium nitrite;
• Finally, accidental exogenous pollution, via water or air for example, can contribute to the introduction of sodium into fuels (sodium being a very widespread element).

• ∘ les acides résiduels des biocarburants (voir la norme EN14214 qui fixe un taux maximal d'acides autorisé)
• ∘ les inhibiteurs de corrosion utilisés pour le transport de produits pétroliers dans certains tuyaux (en anglais « pipes ») tels que le DDSA (anhydride dodécénylsuccinique) ou le HDSA (anhydride hexadécénylsuccinique) ou certains de leurs dérivés fonctionnels tels que les acides.

The possible sources of acids in type Bx fuels can be multiple, for example:

• ∘ residual acids from biofuels (see standard EN14214 which sets a maximum authorized acid level)
• ∘ corrosion inhibitors used for the transport of petroleum products in certain pipes (in English "pipes") such as DDSA (dodecenylsuccinic anhydride) or HDSA (hexadecenylsuccinic anhydride) or some of their functional derivatives such as acids.

With regard to type 2 organic deposits, certain publications state that they may in particular arise from reactions between deposit reducers / dispersants (for example of polyisobutylenesuccinimide type (PIBSI)) and acids (which would be present inter alia as impurities of fatty acid esters of biodiesel).

In the publication SAE 880493, Reduced Injection Needle Mobility Caused by Lacquer Deposits from Sunflower Oil, the authors M Ziejewski and HJ Goettler describe the phenomenon of lacquering and its harmful consequences for the operation of engines running on sunflower oils as fuel.

In SAE 2008-01-0926, Investigation into the Formation and Prevention of Internal Diesel Injector Deposits, the authors J Ullmann, M Geduldig, H Stutzenberger (Robert Bosch GmbH) and R Caprotti, G Balfour (Infineum) also describe the reactions between acids and deposit reducers / dispersants to explain type 2 deposits.

Furthermore, in the publication SAE International, 2010-01-2242, Internal Injector Deposits in High-Pressure Common Rail Diesel Engines, the authors S. Schwab et al., explain that the internal parts of the injectors are generally covered by a slightly colored deposit visible to the naked eye. Their analyzes made it possible to determine that they were mainly sodium salts of alkenyl- (hexadecenyl- or dodecenyl-) - succinic acids; sodium from desiccants, caustic water used in refineries, tank bottom water or sea water, and succinic diacids being used as corrosion inhibitors or present in multifunctional additive packages. Once formed, these salts are insoluble in diesel fuels with low sulfur content, and as they exist in the form of fine particles, pass through diesel filters and come to settle inside the injectors. In this publication, the development of an engine test is described and makes it possible to reproduce the deposits. The publication insists that only diacids generate deposits, unlike mono carboxylic acids or neutral esters of organic acids.

In the publication SAE International, 2010-01-2250, Deposit Control in Modem Diesel Fuel Injection System, the authors, R.Caprotti, N. Bhatti and G. Balfour , are also studying the same type of internal deposits in the injectors and claim that the appearance of deposits is not specifically linked to a type of fuel (B0 or containing EMAG (Bx)) or to a type of vehicle (light vehicles or heavy goods vehicles) equipped with modern engines (common rail). They show the performance of a new deposit reducer / dispersant, effective on all types of deposits (coking and lacquering).

The document DE 10 2004 055589 describes esters obtained from carboxylic acids comprising from 11 to 21 carbon atoms and from diglycerol, oligoglycerols and / or polyglycerols. These esters are used to improve the lubricity of diesel fuel. This document does not concern the improvement of the resistance to lacquering of fuels of the (bio) diesel type of superior quality.

The deposits due to the lacquering phenomenon are insoluble in low sulfur diesel fuels and biodiesel fuels. These deposits exist in the form of fine particles and can pass through diesel filters and settle inside the injectors.

• un ralentissement de la réponse de l'injecteur de carburant,
• le collage des pièces internes, ce qui peut entraîner une perte de contrôle du temps d'injection ainsi que de la quantité de carburant fournie par injection,
• une perte de maniabilité du véhicule,
• des variations de puissance,
• une augmentation de la consommation de carburant,
• une augmentation des polluants,
• une perturbation de la combustion, puisque la quantité de carburant injectée ne sera pas celle prévue en théorie et le profil de l'injection sera différent,
• un ralenti instable du véhicule,
• une augmentation du bruit produit par le moteur,
• une baisse de la qualité de la combustion sur le long terme,
• une baisse de la qualité de la pulvérisation.

The accumulation of lacquering deposits as described above can lead to the following disadvantages:

• a slower response from the fuel injector,
• sticking of the internal parts, which can lead to a loss of control over the injection time and the amount of fuel supplied by injection,
• loss of handling of the vehicle,
• power variations,
• increased fuel consumption,
• an increase in pollutants,
• a combustion disturbance, since the quantity of fuel injected will not be that predicted in theory and the profile of the injection will be different,
• unstable vehicle idling,
• an increase in the noise produced by the engine,
• a decrease in the quality of combustion in the long term,
• a decrease in spray quality.

In the event that there is a strong lacquering-type deposit, the vehicle could have great difficulty starting, or even not starting at all, since the needle allowing the injection would be blocked.

The present invention overcomes the drawbacks indicated above.

The present invention provides additives capable of tangibly improving not only the wear resistance of (bio) diesel or bio (diesel) fuels with low sulfur content, typically less than 100 ppm by mass, but also the resistance to lacquering. high quality (bio) diesel fuels, ie additives with at least 50 ppm by mass of at least one compound chosen from deposit reducers, detergents, dispersants.

The present invention relates to the use of additives to improve the lacquering resistance of fuels of the (bio) diesel type of superior quality, said additives comprising at least 50% by mass of monoester (s) and / or diester (s) of polyglycerols, said polyglycerols having from 2 to 5 glycerol units per molecule and the ester units being derived from fatty acid (s), the fatty acid or acids optionally having one or more ethylenic unsaturations, and more than 50% by number of fatty chains comprising between 12 and 24 carbon atoms.

For the purposes of the present invention, the term “superior quality fuel of the diesel or biodiesel type” means any diesel or biodiesel fuel, in which one or more additives are incorporated to improve its performance (beyond regulatory performance), preferably, any diesel fuel or biodiesel additive with at least 50 ppm by mass of minus one compound chosen from deposit reducers, detergents, dispersants.

The deposit reducer / detergent / dispersant is chosen from:
∘ substituted succinic acid anhydrides, in particular polyisobutenyl succinic anhydrides, often called PIBSA, in which the polyisobutylene group (also called polyisobutene) has a molecular mass of between 140 and 5000 and preferably between 500 and 2000 or preferably between 750 and 1250,

Another subject of the invention relates to (bio) diesel fuels of superior quality and of improved lacquering resistance, additives with at least 50 ppm m / m of at least one compound chosen from deposit reducers, detergents, dispersants and with at least one additive as defined in the present invention.

These problems of resistance to wear of (sulfur) -fuel (bio) diesel fuels and resistance to lacquering of fuels (Bx or biodiesel) are resolved by the use of at least one additive which comprises at least 50% in mass of monoester (s) and / or diester (s) of polyglycerols, said polyglycerols having from 2 to 5 glycerol units per molecule and the esters being derived from fatty acid (s), the fatty acid (s) optionally having one or more ethylenic unsaturations, and the majority, that is to say more than 50% by number of fatty chains comprises between 12 and 24 carbon atoms.

The selective conversion of glycerol into polyglycerols (PG) and into polyglycerol esters (EPG) is an important reaction leading, as indicated above, to various biodegradable surfactants very widely used in industry. Polyglycerols can be obtained by oligomerization of glycerol. Generally, the reaction is carried out in the presence of homogeneous or heterogeneous acidic or basic catalysts.

In general, polyglycerols are mixtures of close homologues with a majority targeted molecule. Thus for example the diglycerol marketed by the company Fluka has the following distribution with 87% diglycerol and 10% tri- and tetraglycerol.

The synthesis of mono- and diesters of fatty acid (s) and polyglycerol (s) is known per se; they can for example be prepared by esterification of fatty acid (s) and of diglycerol in the case of the mono- and diesters of diglycerol (or of triglycerol in the case of the mono- and diesters of triglycerol). The product resulting from this esterification reaction comprises a mixture of mono-, di-; polyglycerol tri- and tetra-esters (for example diglycerol, triglycerol, mixture of di- and triglycerol), as well as small amounts of fatty acid (s) and polyglycerol, (for example diglycerol, triglycerol, mixture of di- and triglycerol) which have not reacted.

For example, the patent EP 1,679,300 describes a process for producing fatty acid esters and polyglycerol, in which glycerol is added to a reaction mixture obtained by a direct esterification reaction between polyglycerol and a fatty acid at a temperature ranging from 60 ° C to below 180 ° C, and the glycerol phase containing unreacted polyglycerols is separated and removed.

Esters of fatty acid (s) and polyglycerols have long been known as nonionic surfactants; being biodegradable and biocompatible, they are used in particular for food and personal care.

In US 5,632,785 , polyglycerol esters are described as “Fuel Economy” additives for any type of fuel; only decaglycerol tetraoleate is exemplified in a petrol fuel as a "Fuel Economy" additive.

où n ≥ 2, représente le nombre de motifs glycérol du polyglycérol.Polyglycerols can be represented by one of the following general formulas:

where n ≥ 2, represents the number of glycerol units of the polyglycerol.

Polyglycerols (PG) are characterized by their molecular mass, their number of hydroxyl groups and their hydroxyl number, as mentioned in the table below. polyglycerol not Molecular weight Number of OH Hydroxyl number (mg KOH / g) diglycerol 2 166 4 1352 triglycerol 3 240 5 1169 tetraglycerol 4 314 6 1071 pentaglycerol 5 388 7 1012

The fatty acids from which the polyglycerol esters according to the invention are derived can be chosen from stearate, isostearate, oleate, linoleate, linolenate, behenate, arachidonate, ricinoleate, palmitate, myristate, laurate, caprate, and their mixtures and the corresponding esters such as the Diglyceryl monostearate mixture ( CAS 12694-22-3 ), Polyglyceryl - 2 diisostearate, or diglyceryl diisostearate ( CAS 67938-21-0 ), Polyglyceryl-2 isostearate ( CAS 73296-86-3 ), Polyglyceryl-2 isostearate ( CAS 81752-33-2 ), Polyglyceryl-2 oleate ( CAS 96499-68-2 ), Diglyceryl monooleate ( CAS 49553-76-6 ), Polyglyceryl-2 triisostearate ( CAS 120486-24-0 ), 3-polyglyceryl caprate ( CAS 133654-02-1 ), Triglyceryl caprate ( CAS 51033-30-8 ), Polyglyceryl-3 distearate ( CAS 94423-19-5 ), Polyglyceryl-3 isostearate ( CAS 127512-63-4 ), Polyglyceryl-3 diisostearate ( CAS 66082-42-6 ), 3-polyglyceryl monooleate ( CAS 33940-98-6 ), Polyglyceryl-3 dioleate ( CAS 79665-94-4 ), Polyglycerol-3 trioleate ( CAS 79665-95-5 ).

The fatty acids can come from the transesterification or saponification of vegetable oils and / or animal fats. The preferred vegetable oils and / or animal fats will be chosen as a function of their oleic acid concentration. We can refer for example to Table 6.21 of chapter 6 of the book Carburants & Moteurs by JC Guibet and E. Faure, 2007 edition in which the compositions of several vegetable oils and animal fats are indicated.

The fatty acids may also come from fatty acids derived from tall oil (in English "tall oil fatty acid" TOFA) which comprise a majority amount of fatty acids, typically greater than or equal to 90% by mass as well as resin acids and unsaponifiable in a minority quantity, ie in quantities generally less than 10% by mass.

Preferred additives according to the invention capable of improving the wear resistance of low sulfur (bio) diesel fuels and the lacquering resistance of high quality (bio) diesel fuels include partial esters of diglycerol or triglycerol with at least 50% by mass of monoester - and / or diester (s) of oleic acid and diglycerol, therefore of mono-oleate (s) of diglycerol (DGMO) and / or dioleate (s) of diglycerol (DGDO).

Other preferred additives comprise at least 50% by mass of mono-and / or diester (s) of oleic acid and of triglycerol, therefore of mono-oleate (s) of triglycerol and / or of dioleate (s) of triglycerol.

Other preferred additives comprise at least 50% by mass of mono-and / or diester (s) of oleic acid and diglycerol and / or triglycerol.

The use of these additives makes it possible to improve the lubricating power of diesel or biodiesel fuels with low sulfur content for compression engines in which they are incorporated. The use of these additives in (bio) diesel fuels makes it possible to reduce the rate of wear in the fuel intake or injection system, in particular on the injection pump.

Diesel fuels (liquid fuels for compression engines) include middle distillates with a boiling temperature between 100 and 500 ° C; their starting crystallization temperature TCC is often greater than or equal to -20 ° C, generally between -15 ° C and + 10 ° C. These distillates are mixtures of bases which can be chosen, for example, from distillates obtained by direct distillation of petroleum or crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates from catalytic cracking and / or hydrocracking of vacuum distillates, distillates resulting from ARDS conversion processes ( by atmospheric residue desulfurization) and / or visbreaking.

Diesel fuels can also contain light cuts such as petrol obtained from distillation, catalytic or thermal cracking units, isomerization, desulphurization alkylation units, steam cracking units.

• les coupes les plus lourdes issues des procédés de craquage et de viscoréduction concentrées en paraffines lourdes, comprenant plus de 18 atomes de carbone,
• les distillats synthétiques issus de la transformation du gaz tels que ceux issus du procédé Fischer Tropsch,
• les distillats synthétiques résultant du traitement de la biomasse d'origine végétale et/ou animale, comme notamment le NexBTL, prise seule ou en mélange. La biomasse végétale ou animale et les huiles végétales ou animales pouvant être hydrotraitées ou hydrodésoxygénées,
• les gazoles de coker,
• les alcools, tels que méthanol, éthanol, butanols, les éthers, (MTBE, ETBE, ...) en général utilisés en mélange avec les carburants essence, mais parfois avec des carburants plus lourds de type gazole,
• les huiles végétales et/ou animales et/ou leurs esters, tels que les esters méthyliques ou éthyliques d'huiles végétales ou d'acides gras (EMHV, EEHV, EMAG),
• les huiles végétales et/ou animales hydrotraitées et/ou hydrocraquées et/ou hydrodéoxygénées (HDO),
• et/ou encore les biodiesels d'origine animale et/ou végétale.

In addition, diesel fuels can contain new sources of distillates, among which we can mention:

• the heaviest cuts resulting from cracking and visbreaking processes concentrated in heavy paraffins, comprising more than 18 carbon atoms,
• synthetic distillates from gas processing, such as those from the Fischer Tropsch process,
• synthetic distillates resulting from the treatment of biomass of plant and / or animal origin, such as in particular NexBTL, taken alone or as a mixture. Plant or animal biomass and vegetable or animal oils which can be hydrotreated or hydrodeoxygenated,
• coker gas oils,
• alcohols, such as methanol, ethanol, butanols, ethers, (MTBE, ETBE, ...) generally used in admixture with petrol fuels, but sometimes with heavier fuels of the diesel type,
• vegetable and / or animal oils and / or their esters, such as methyl or ethyl esters of vegetable oils or fatty acids (EMHV, EEHV, EMAG),
• hydrotreated and / or hydrocracked and / or hydrodeoxygenated (HDO) vegetable and / or animal oils,
• and / or biodiesel of animal and / or vegetable origin.

These new fuel and combustible bases can be used alone or in mixture with conventional petroleum middle distillates as fuel base (s); they generally comprise long paraffinic chains greater than or equal to 10 carbon atoms and preferably from C14 to C30.

In the context of the present invention, diesel fuels have a sulfur content less than or equal to 500 ppm by mass, advantageously less than or equal to 100 ppm by mass, and which can be lowered to a content less than or equal to 50 ppm by mass, or even even less than or equal to 10 ppm by mass (this is the case of diesel fuels for current vehicles whose sulfur level according to the European standard EN 590 currently in force must be less than or equal to 10 ppm by mass).

The wear resistance and lacquering resistance additives for diesel fuels according to the invention can be incorporated into fuels up to a value of up to 10% by mass, and advantageously so that the concentration of mono- and diglycerol and / or triglycerol di-ester (s) in the final fuel is between 20 and 1,000 ppm by mass, and preferably between 30 and 200 ppm by mass m / m, that is to say ppm by mass based on the total mass of the additive fuel.

According to one embodiment, the top quality (bio) diesel fuel compositions contain at least 50 ppm by mass of at least one compound chosen from deposit reducers, detergents, dispersants and contain at least one additive according to the invention. invention and optionally at least one or more other functional additives.

Those skilled in the art will easily adapt the additive additive rate according to the invention according to the possible dilution of the additive in a solvent, the possible presence of other components derived for example from the esterification reaction and / or other functional additives incorporated in the final fuel.

The anti-wear and anti-lacquering additives of the present invention can be used alone or in admixture with other functional additives, such as deposit reducers / dispersants, antioxidants, combustion improvers, corrosion inhibitors , cold-keeping additives (improving cloud point, sedimentation rate, filterability and / or cold flow), dyes, demulsifiers, metal deactivators, defoamers, agents improving the cetane number, co-solvents, compatibilizing agents, other anti-wear additives than those of the present invention, etc.

• ❖ les additifs améliorant de combustion ; pour les carburants de type gazole, on peut citer les additifs procétane, notamment (mais non limitativement) choisis parmi les nitrates d'alkyle, de préférence le nitrate de 2-éthyl hexyle, les peroxydes d'aryle, de préférence le peroxyde de benzyle, et les peroxydes d'alkyle, de préférence le peroxyde de di ter-butyle; pour les carburants de type essence, on peut citer les additifs améliorant l'indice d'octane; pour les combustibles tels que fioul domestique, fioul lourd, fioul marine, on peut citer le méthylcyclopentadiényl manganèse tricarbonyle (MMT) ;
• ❖ les additifs anti-oxydants, tels que des amines aliphatiques, aromatiques, les phénols encombrés, tels que BHT, BHQ ;
• ❖ les désémulsionnants ou désémulsifiants ;
• ❖ les additifs anti-statiques ou améliorants de conductivité ;
• ❖ les colorants ;
• ❖ les additifs anti-mousse, notamment (mais non limitativement) choisis par exemple parmi les polysiloxanes, les polysiloxanes oxyalkylés, et les amides d'acides gras issus d'huiles végétales ou animales; des exemples de tels additifs sont donnés dans EP 861 182 , EP 663 000 , EP 736 590 ;
• ❖ les additifs anti-corrosion tels que les sels d'ammonium d'acides carboxyliques ;
• ❖ les agents chélatants et/ou les agents séquestrants de métaux, tels que les triazoles, les disalicylidène alkylène diamines, et notamment le N,N' bis (salicylidène)propane diamine ;
• ❖ les additifs de tenue à froid et notamment les additifs améliorant le point de trouble, notamment (mais non limitativement) choisis dans le groupe constitué par les terpolymères oléfine à chaîne longue/ester (méth)acrylique/maléimide, et les polymères d'esters d'acides fumarique /maléique. Des exemples de tels additifs sont donnés dans EP 71 513 , EP 100 248 , FR 2 528 051 , FR 2 528 051 , FR 2 528 423 , EP1 12 195 , EP 1 727 58 , EP 271 385 , EP 291367 ; les additifs d'anti-sédimentation et/ou dispersants de paraffines notamment (mais non limitativement) choisis dans le groupe constitué par les copolymères acide (méth)acrylique/(méth)acrylate d'alkyle amidifié par une polyamine, les alkénylsuccinimides de polyamine, les dérivés d'acide phtalamique et d'amine grasse à double chaîne; des résines alkyl phénol/aldéhyde ; des exemples de tels additifs sont donnés dans EP 261 959 , EP 593 331 , EP 674 689 , EP 327 423 , EP 512 889 , EP 832 172 ; US 2005/0223631 ; US 5 998 530 ; WO 93/14178 ; les additifs polyfonctionnels d'opérabilité à froid choisis notamment dans le groupe constitué par les polymères à base d'oléfine et de nitrate d'alkényle tels que décrits dans EP 573 490 ;
• ❖ d'autres additifs améliorant la tenue à froid et la filtrabilité (CFI), tels que les copolymères EVA et/ou EVP ;
• ❖ les passivateurs de métaux, tels que les triazoles, les benzotriazoles alkylés ;
• ❖ les neutralisateurs d'acidité tels que les alkylamines cycliques ;
• ❖ les marqueurs, notamment les marqueurs imposés par la réglementation, par exemple les colorants spécifiques à chaque type de carburant ou combustible.
• ❖ les agents parfumants ou masquants d'odeurs, tels que ceux décrits dans EP 1 591 514 ;
• ❖ d'autres additifs de lubrifiance, agents anti-usure et/ou modificateurs de frottement que ceux décrits précédemment, notamment (mais non limitativement) choisis dans le groupe constitué par les acides gras et leurs dérivés ester ou amide, notamment le monooléate de glycérol, et les dérivés d'acides carboxyliques mono- et polycycliques; des exemples de tels additifs sont donnés dans les documents suivants: EP 680 506 , EP 860 494 , WO 98/04656 , EP 915 944 , FR2 772 783 , FR 2 772 784 .

In a non-exhaustive manner, the other functional additive (s) can be chosen from:

• ❖ combustion enhancing additives; for diesel fuels, procetane additives may be mentioned, in particular (but not limited to) chosen from alkyl nitrates, preferably 2-ethyl hexyl nitrate, aryl peroxides, preferably benzyl peroxide , and alkyl peroxides, preferably di-butyl peroxide; for petrol type fuels, there may be mentioned additives improving the octane number; for fuels such as heating oil, heavy fuel oil, marine fuel oil, mention may be made of methylcyclopentadienyl manganese tricarbonyl (MMT);
• ❖ antioxidant additives, such as aliphatic, aromatic amines, hindered phenols, such as BHT, BHQ;
• ❖ demulsifiers or demulsifiers;
• ❖ anti-static or conductivity improving additives;
• ❖ dyes;
• ❖ anti-foam additives, in particular (but not limited to) chosen for example from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides derived from vegetable or animal oils; examples of such additives are given in EP 861,182 , EP 663,000 , EP 736,590 ;
• ❖ anti-corrosion additives such as ammonium salts of carboxylic acids;
• ❖ chelating agents and / or metal sequestering agents, such as triazoles, disalicylidene alkylene diamines, and in particular N, N 'bis (salicylidene) propane diamine;
• ❖ cold-keeping additives and in particular additives improving the cloud point, in particular (but not limited to) chosen from the group consisting of long chain olefin terpolymers / (meth) acrylic ester / maleimide, and ester polymers fumaric / maleic acids. Examples of such additives are given in EP 71,513 , EP 100 248 , FR 2,528,051 , FR 2,528,051 , FR 2 528 423 , EP1 12,195 , EP 1,727,58 , EP 271,385 , EP 291367 ; paraffin anti-sedimentation additives and / or dispersants, in particular (but not limited to) chosen from the group consisting of (meth) acrylic acid / (meth) acrylate copolymers amidified by a polyamine, polyamine alkenyl succinimides, phthalamic acid and fatty double chain amine derivatives; alkyl phenol / aldehyde resins; examples of such additives are given in EP 261,959 , EP 593,331 , EP 674,689 , EP 327,423 , EP 512,889 , EP 832 172 ; US 2005/0223631 ; US 5,998,530 ; WO 93/14178 ; the polyfunctional cold operability additives chosen in particular in the group consisting of polymers based on olefin and alkenyl nitrate as described in EP 573,490 ;
• ❖ other additives improving cold resistance and filterability (CFI), such as EVA and / or EVP copolymers;
• ❖ metal passivators, such as triazoles, alkylated benzotriazoles;
• ❖ acidity neutralizers such as cyclic alkylamines;
• ❖ the markers, in particular the markers imposed by the regulations, for example the dyes specific to each type of fuel or combustible.
• ❖ perfuming agents or masks of odors, such as those described in EP 1,591,514 ;
• ❖ other lubricant additives, anti-wear agents and / or friction modifiers than those described above, in particular (but not limited to) chosen from the group consisting of fatty acids and their ester or amide derivatives, in particular glycerol monooleate , and derivatives of mono- and polycyclic carboxylic acids; examples of such additives are given in the following documents: EP 680 506 , EP 860,494 , WO 98/04656 , EP 915,944 , FR2 772 783 , FR 2,772,784 .

Any other additives are generally incorporated in amounts ranging from 50 to 1,500 ppm m / m, that is to say ppm by mass based on the total mass of the additive fuel.

These additives can be incorporated into fuels according to any known process; by way of example, the additive or the mixture of additives can be incorporated in the form of a concentrate comprising the additive (s) and a solvent, compatible with the (bio) diesel fuel, the additive being dispersed or dissolved in the solvent. Such concentrates generally contain from 20 to 95% by mass of solvents.

Solvents are organic solvents which generally contain hydrocarbon solvents. By way of example of solvents, mention may be made of petroleum fractions, such as naphtha, kerosene, heating oil; aliphatic and / or aromatic aromatic hydrocarbons such as hexane, pentane, decane, pentadecane, toluene, xylene, and / or ethylbenzene and alkoxyalkanols such as 2-butoxyethanol and / or mixtures of hydrocarbons such as mixtures of commercial solvents such as Solvarex 10, Solvarex LN, Solvent Naphta, Shellsol AB, Shellsol D, Solvesso 150, Solvesso 150 ND, Solvesso 200, Exxsol, ISOPAR and possibly polar dissolution aids, such as 2-ethylhexanol, decanol, isodecanol and / or isotridecanol.

The invention relates to the use of at least one composition of additives according to the invention incorporated in a diesel or biodiesel fuel of superior quality to improve resistance to lacquering, ie fouling on the head and / or on the body. of the needles of the fuel injection system but also throughout the system for controlling the lifting of needles (valves) of the injection system, in particular for engines fitted with fuel injection systems of Euro 4 to Euro 6 type.

The invention also relates to a method for improving lacquering resistance comprising the introduction of additives into a fuel of high quality (bio) diesel type, said additives comprising at least 50% by mass of monoester (s) and / or diester (s) of polyglycerols, said polyglycerols having from 2 to 5 glycerol units per molecule is the ester units being derived from fatty acid (s), the fatty acid (s) optionally having one or more ethylenic unsaturations, and more than 50% by number of fatty chains comprising between 12 and 24 carbon atoms.

• les carburants de type (bio)gazole de qualité supérieure ont un taux de soufre inférieur ou égal à 500 ppm,
• les additifs comprennent des esters partiels de diglycérol et/ou de triglycérol,
• les esters partiels de diglycérol et/ou de triglycérol comprennent au moins 50 % en masse de monoester - et/ou de diester(s) d'acide oléique et de diglycérol, donc de mono-oléate(s) de diglycérol (DGMO) et/ou de dioléate(s) de diglycérol (DGDO) soit au moins 50 % en masse de mono- et/ou de diester(s) d'acide oléique et de triglycérol, soit au moins 50 % en masse de mono- et/ou de diester(s) d'acide oléique et de diglycérol et/ou de triglycérol,
• les additifs comprennent en outre un ou plusieurs autres additifs fonctionnels, tels que les réducteurs de dépôt/dispersants, les anti-oxydants, les améliorants de combustion, les inhibiteurs de corrosion, les additifs de tenue à froid (améliorant le point de trouble, la vitesse de sédimentation, la filtrabilité et/ou l'écoulement à froid), les colorants, les désémulsionnants, les désactivateurs de métaux, les agents anti-mousse, les agents améliorant l'indice de cétane, les co-solvants, les agents compatibilisants, d'autres additifs de lubrifiance, agents anti-usure et/ou modificateurs de frottement, et éventuellement un ou plusieurs solvants.

Preferably, the method for improving the lacquering resistance according to the invention has the following characteristics:

• higher quality (bio) diesel fuels have a sulfur content of 500 ppm or less,
• the additives include partial esters of diglycerol and / or triglycerol,
• the partial esters of diglycerol and / or of triglycerol comprise at least 50% by mass of monoester - and / or of diester (s) of oleic acid and of diglycerol, therefore of mono-oleate (s) of diglycerol (DGMO) and / or diglycerol dioleate (s) (DGDO) or at least 50% by mass of mono- and / or oleic acid and triglycerol diester (s), or at least 50% by mass of mono- and / or diester (s) of oleic acid and diglycerol and / or triglycerol,
• the additives also comprise one or more other functional additives, such as deposit reducers / dispersants, antioxidants, combustion improvers, corrosion inhibitors, cold-resistance additives (improving the cloud point, the sedimentation rate, filterability and / or cold flow), dyes, demulsifiers, metal deactivators, anti-foaming agents, cetane index improving agents, co-solvents, compatibilizers, other lubricating additives, anti-wear agents and / or friction modifiers, and possibly one or more solvents.

According to a particular embodiment, the method of improving the lacquering resistance according to the invention also makes it possible to improve the resistance to wear, in particular of injectors, and the lubricity of (bio) diesel fuels having a rate of sulfur less than or equal to 500 ppm by mass.

• un ralentissement de la réponse de l'injecteur de carburant,
• le collage des pièces internes, ce qui peut entraîner une perte de contrôle du temps d'injection ainsi que de la quantité de carburant fournie par injection,
• une perte de maniabilité du véhicule,
• des variations de puissance,
• une augmentation de la consommation de carburant,
• une augmentation des polluants,
• une perturbation de la combustion, puisque la quantité de carburant injectée ne sera pas celle prévue en théorie et le profil de l'injection sera différent,
• un ralenti instable du véhicule,
• une augmentation du bruit produit par le moteur,
• une baisse de la qualité de la combustion sur le long terme,
• une baisse de la qualité de la pulvérisation.

The method of improving the lacquering resistance according to the invention makes it possible to avoid and / or reduce and / or delay:

• a slower response from the fuel injector,
• sticking of the internal parts, which can lead to a loss of control over the injection time and the amount of fuel supplied by injection,
• loss of handling of the vehicle,
• power variations,
• increased fuel consumption,
• an increase in pollutants,
• a combustion disturbance, since the quantity of fuel injected will not be that predicted in theory and the profile of the injection will be different,
• unstable vehicle idling,
• an increase in the noise produced by the engine,
• a decrease in the quality of combustion in the long term,
• a decrease in spray quality.

• Le moteur utilisé est un moteur quatre cylindres et 16 soupapes diesel à injection haute pression Common Rail d'une cylindrée de 1.500 cm³ et d'une puissance de 80 CV : la régulation de pression d'injection du carburant se faisant dans la partie haute pression de la pompe.
• Le point de puissance est de 40 h à 4.000 trs/min ; la position de l'injecteur dans la chambre est descendue de 1 mm par rapport à sa position nominale, ce qui d'une part favorise le dégagement d'énergie thermique de la combustion, et d'autre part rapproche l'injecteur de la chambre de combustion.
• Le débit de carburant injecté est ajusté de manière à obtenir une température à l'échappement de 750°C en début d'essai.
• L'avance à l'injection a été augmentée de 1,5° vilebrequin par rapport au réglage nominal (on passe de + 12,5° à + 14° vilebrequin) toujours dans le but d'augmenter les contraintes thermiques subies par la buse de l'injecteur.
• Enfin, pour augmenter les contraintes subies par le carburant, la pression d'injection a été augmentée de 10 MPa par rapport à la pression nominale (c'est-à-dire passage de 140 MPa à 150 MPa) et la température est régulée à 65°C en entrée pompe haute pression.

The inventors have also developed a new reliable and robust method for evaluating the sensitivity of (bio) diesel fuels, in particular those of superior quality, lacquering. This method, unlike the methods described in the publications cited above, is not a laboratory method but is based on engine tests and therefore has a technical interest and makes it possible to quantify the effectiveness of additives or compositions of additives against lacquering. The method of measuring lacquering developed by the inventors is detailed below:

• The engine used is a four-cylinder, 16-valve diesel engine with common rail high pressure injection with a displacement of 1,500 cm ³ and a power of 80 CV: the fuel injection pressure regulation is done at the top pump pressure.
• The power point is 40 h at 4,000 rpm; the position of the injector in the chamber is lowered by 1 mm from its nominal position, which on the one hand promotes the release of thermal energy from combustion, and on the other hand brings the injector closer to the chamber combustion.
• The flow rate of injected fuel is adjusted so as to obtain an exhaust temperature of 750 ° C at the start of the test.
• The injection advance has been increased by 1.5 ° crankshaft compared to the nominal setting (we go from + 12.5 ° to + 14 ° crankshaft) always with the aim of increasing the thermal stresses undergone by the nozzle of the injector.
• Finally, to increase the stresses to which the fuel is subjected, the injection pressure has been increased by 10 MPa compared to the nominal pressure (i.e. passing from 140 MPa to 150 MPa) and the temperature is regulated at 65 ° C at high pressure pump inlet.

The technology used for the injectors requires a high fuel return, which promotes the degradation of the fuel since it can be subjected to several cycles in the high pressure pump and the Common Ball before being injected into the combustion chamber.

• Les 20 premières heures sont effectuées avec un gazole B7 de qualité supérieure (contenant du détergent de type PIBSA et un modificateur de frottement acide) connu pour sa tendance à générer du lacquering. Après 20h, deux des quatre injecteurs sont démontés et côtés afin de valider la quantité de dépôts qui sont présents et deux injecteurs neufs sont alors installés à la place.
• Les 20 dernières heures de l'essai sont réalisées avec le produit à évaluer. A la fin de l'essai (40h au total), les injecteurs sont démontés et côtés.

A variant of the method for testing the clean-up effect (ie cleaning of type 1 and / or type 2 deposits) has also been developed. It is based on the previous method but is separated into two parts of 20h:

• The first 20 hours are carried out with high-quality B7 diesel fuel (containing PIBSA type detergent and an acid friction modifier) known for its tendency to generate lacquering. After 8 p.m., two of the four injectors are dismantled and set aside in order to validate the quantity of deposits that are present and two new injectors are then installed instead.
• The last 20 hours of the test are carried out with the product to be evaluated. At the end of the test (40 hours in total), the injectors are removed and removed.

• Lot 1 : 2 injecteurs ayant vu 20h de carburant de qualité supérieure connu pour sa tendance à générer du lacquering.
• Lot 2 : 2 injecteurs ayant vu 20h de carburant de qualité supérieure connu pour sa tendance à générer du lacquering + 20h de produit à évaluer.
• Lot 3 : 2 injecteurs ayant vu 20h de produit à évaluer.

At the end of the test, three lots of two injectors are available:

• Lot 1: 2 injectors having seen 20 hours of high quality fuel known for its tendency to generate lacquering.
• Lot 2: 2 injectors having seen 20h of high quality fuel known for its tendency to generate lacquering + 20h of product to be evaluated.
• Lot 3: 2 injectors having seen 20 hours of product to be evaluated.

Expression of results

To ensure the validity of the result, various parameters are checked during the test: power, torque and fuel consumption indicate whether the injector is clogged or if its operation is deteriorated by the formation of deposits since the operating point is the same throughout the test.

The characteristic temperatures of the various fluids (coolant, fuel, oil) allow the validity of the tests to be checked. The fuel is regulated at 65 ° C at the pump inlet, the coolant is regulated at 90 ° C at the engine outlet.

The smoke values make it possible to control the timing of combustion at the start of the test (target value of 3FSN) and to ensure that it is well repeatable from one test to another.

• L'échelle des notes varie de -2,5 (cas d'un important dépôt) à 10 (cas d'une aiguille neuve sans aucun dépôt). La note finale est une moyenne pondérée des notes sur toutes les surfaces cotées de l'aiguille
• Surface totale : partie cylindre (suivant directement la partie conique) + partie conique : 100 %, dont pondération surfacique de la partie cylindre (suivant directement la partie conique) : 68 % et pondération surfacique de la partie conique : 32 % ; voir la figure 1 ci-jointe (les % indiqués correspondent au quart de la surface des aiguilles : la pondération surfacique globale est donc de 17^∗4 = 68 %)
• Un seuil de performance produit a été déterminé par rapport à cette procédure de cotation: Résultat < 4 = Mauvais, résultat > 4 = Satisfaisant.

The injectors are disassembled at the end of the test to view and rate the deposits formed along the needles. The procedure for rating needles is as follows:

• The scale of the notes varies from -2.5 (case of a large deposit) to 10 (case of a new needle without any deposit). The final grade is a weighted average of the grades on all of the needle's rated surfaces
• Total area: cylinder part (directly following the conical part) + conical part: 100%, of which surface weighting of the cylinder part (directly following the conical part): 68% and surface weighting of the conical part: 32%; see it figure 1 attached (the% indicated corresponds to a quarter of the surface of the needles: the overall surface weighting is therefore 17 ^∗ 4 = 68%)
• A product performance threshold has been determined in relation to this rating procedure: Result <4 = Poor, result> 4 = Satisfactory.

The following examples illustrate the invention without limiting it.

Example 1 - Preparation of anti-wear and anti-lacquering additives according to the invention

In the presence of a MeONa type catalyst, 90 g of diglycerol is reacted at 170 ° C. with 500 g of oleic sunflower oil (concentration in oleic acid equivalent under reduced pressure of 300 mbar (0.03 MPa)) for 6 hours.

The procedure is repeated above, a 2 ^nd time for preparing a ^2nd product sample.

The mass composition of the products obtained, measured by steric exclusion chromatography, is indicated in Table 1 below. Table 1 Component DGMO 1 DGMO 2 Diglycerol monoester 24.7 31.4 Diglycerol diester 41.2 30.2 Triester of diglycerol / Triglycerides 18.6 14.4 Diglycerol tetraester 6.6 6.4 Monoglyceride 2.4 nd Diglyceride 1 2.1 Diglycerol nd 3.3 Oleic sunflower methyl ester 5.3 6.4 na = not determined

Example 2- Wear resistance measurement (HFRR bench)

One of the additives according to the invention prepared in Example 1 is incorporated into a diesel fuel and the lubricating power of the fuel additive is measured according to the HFRR method described in standard ASTM 12156-1. The diesel used in this example is a "biofree" B0 fuel and devoid of lubricant additive, containing less than 10 ppm / m of sulfur, the aromatic character of which is not very pronounced (22% m / m) and the density relatively low (821.9 g / L).

By way of comparison, the same fuel is added on the one hand with an additive consisting essentially of glycerol mono-oleate (PC 60) and on the other hand with a TOFA, as described in EP 915,944 .

The details of each fuel composition tested, as well as the average wear diameter obtained on the HFRR bench are collated in Table 2. Table 2 Test No. 2-1 2-2 (comparison) 2-3 (comparison) 2-4 2-5 Additive added 0 glycerol monoleate (MGMO) TOFA DGMO 1 DGMO 2 @ 0 ppm (m / m) 680 µm 680 µm 680 µm 680 µm 680 µm @ 200 ppm (m / m) --- 298 µm 362 µm 279 µm 281 µm @ 500 ppm (m / m) --- 198 µm 320 µm 192 µm 171 µm @ 10,000 ppm (m / m) --- 176 µm 199 µm 207 µm 168 µm

Example 3- Wear resistance measurement (HFRR bench)

In a “biofree” B0 diesel fuel without lubricant additive, containing less than 10 ppm / m of sulfur and whose aromatic character is not very pronounced (22% m / m) and relatively low density (821.9 g / L), either a single lubricant additive (DGMO, MGMO or TOFA) is incorporated, or a mixture of at least 2 lubricant additives including one of the DGMO additives according to the invention of Example 1 and at least one additive known lubricity (TOFA) and / or glycerol mono-oleate on the other hand. The lubricating power of the product is measured according to the HFRR method described in ASTM 12156-1. AT.

The details of each fuel composition tested as well as the average wear diameter obtained on the HFRR bench and the friction coefficient are shown in Table 3 below.

Example 4- Lacquering resistance measurements

According to the lacquering resistance measurement procedure described above, the performance of several packets of additives introduced into a diesel matrix representative of the French market is evaluated (B7 = diesel produced in France containing 7% of EMAG (methyl ester of fatty acids) and meeting EN 590). The details of each fuel composition tested, as well as the results obtained are shown in Table 4. Tests G, G 'and G "correspond to the same test according to the procedure for measuring the resistance to lacquering clean-up version. The result G corresponds to the batch of injectors 1, G 'to the batch of injectors 2 and G "to the batch of injectors 3 according to the description given above.

The quantities indicated in table 4 are mass quantities (m / m) Table 4 Test No. AT B VS D E F G G ' G " Fuel B7 B7 B7 B7 B7 B7 B7 B7 B7 Diesel detergent type PIBSA --- 330 ppm 330 ppm 330 ppm 170 ppm 170 ppm 330 ppm 330 then 170 ppm 170 ppm TOFA --- 200 ppm --- --- 200 ppm --- 200 ppm 200 then 0 ppm --- MGMO --- --- 200 ppm --- --- --- --- --- --- DGMO --- --- --- 200 ppm --- 200 ppm --- 0 then 200 ppm 200 ppm Type 1 deposit rating 8.7 -1 1.7 9.0 5.0 8.0 1.9 7.9 8.0 Listing of type 2 deposits 7.1 -1 6.3 7.9 2.8 7.2 2.5 6.4 5.6 Overall rating 8.2 -1 3.2 8.7 2.8 7.8 2.1 7.9 7.3

Claims (11)

1. Use of additives for improving the lacquering resistance of diesel or biodiesel fuels comprising at least 50 ppm by weight of at least one component chosen from deposit reducers, detergents and dispersants, said additives comprising at least 50% by weight of polyglycerol monoester(s) and/or diester(s), said polyglycerols having from 2 to 5 glycerol units per molecule and the ester units being fatty acid derivatives, the fatty acid(s) optionally having one or more ethylenic unsaturations, and more than 50% by number of fatty chains comprising between 12 and 24 carbon atoms, and said component chosen from deposit reducers, detergents and dispersants being chosen from substituted succinic acid anhydrides.
2. Use according to claim 1, wherein the diesel or biodiesel fuels comprising at least 50 ppm by weight of at least one component chosen from deposit reducers, detergents and dispersants have a sulphur content less than or equal to 500 ppm by weight.
3. Use according to claim 1 or 2, wherein the additives comprise partial esters of diglycerol and/or triglycerol.
4. Use according to claim 3, wherein the partial esters of diglycerol and/or triglycerol comprise either at least 50% by weight of monoester(s) and/or diester(s) of oleic acid and diglycerol, therefore of diglycerol mono-oleate(s) (DGMO) and/or diglycerol dioleate(s) (DGDO) or at least 50% by weight of mono- and/or diester(s) of oleic acid and triglycerol, or at least 50% by weight of mono- and/or diester(s) of oleic acid and diglycerol and/or triglycerol.
5. Use according to any one of claims 1 to 4, wherein the additives further comprise one or more other functional additives and optionally one or more solvents.
6. Use according to claim 5, wherein the functional additives are chosen from deposit reducers/dispersants, anti-oxidants, combustion improvers, corrosion inhibitors, low temperature performance additives, colorants, de-emulsifiers, metal deactivators, anti-foaming agents, agents improving the cetane number, cosolvents, compatibilizing agents, other lubricant additives, anti-wear agents and/or friction modifiers.
7. Use according to claim 1, wherein the substituted succinic acid anhydrides are chosen from polyisobutenyl succinic anhydrides (PIBSA), in which the polyisobutylene group has a molecular mass comprised between 140 and 5000.
8. Use according to any one of claims 1 to 7 for further improving the wear resistance and the lubricity of diesel and biodiesel fuels having a sulphur content less than or equal to 500 ppm by weight.
9. Compositions of diesel or biodiesel fuel containing at least one additive as defined in any one of claims 1 and 3-6 and at least 50 ppm by weight of at least one component chosen from deposit reducers, detergents and dispersants, said component being chosen from substituted succinic acid anhydrides, said compositions having a concentration in mono- and di-ester(s) of diglycerol and/or of triglycerol comprised between 20 and 1000 ppm by weight.
10. Compositions of diesel or biodiesel fuel according to claim 9, wherein the substituted succinic acid anhydrides are chosen from polyisobutenylsuccinic anhydrides (PIBSA) in which the polyisobutylene group has a molecular mass comprised between 140 and 5000.
11. Compositions of diesel or biodiesel fuel according to any one of the claims 9 or 10 having a concentration in mono- and di-ester(s) of diglycerol and/or of triglycerol comprised between 30 and 200 ppm by weight.

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