FR2964115A1 - ENGINE LUBRICANT - Google Patents

Abstract

The subject of the invention is a lubricating composition comprising: (a) one or more base oils, (b) at least one comb polymer formed of a polyalkyl (meth) acrylate main chain, and hydrocarbon side chains comprising at least one 50 carbon atoms, (c) at least one nitrogen-containing organic friction modifier selected from fatty amines, optionally alkoxylated, fatty amides or imides obtained by condensation of fatty amines and carboxylic acids, alone or as a mixture, (d) ) optionally, one or more organometallic friction modifiers of organomolybdenum type. Use for the lubrication of gasoline or diesel 4-stroke engines of light vehicles, preferably hybrid vehicles.

Description

1 LUBRICANT ENGINE

TECHNICAL FIELD The present invention relates to lubricating compositions for gasoline vehicle engines or diesel vehicles, enabling a reduction in the fuel consumption of said vehicles.

Technological Background Energy efficiency and reduced fuel consumption of 10 engines is a growing concern. It is known that the engine lubricants used in said vehicles have an important role in this regard. Frictional energy losses between the various engine components occur, depending on the engine parts, either in hydrodynamic, elastohydrodynamic, or limit friction regimes. The choice of viscosity index improving (VI improvers) bases and polymers has an influence on the hydrodynamic and elastohydrodynamic losses, while the choice of friction modifiers influences the limit friction friction losses. . However, the formulation of a fuel-saving engine lubricant is not limited to the selection of these different components independently of each other. The interactions between the different components must be taken into account, and the other lubricant performances, such as the stability of the viscosity, the inhibition of the corrosion, the dispersing power ... must not be altered. Examples of engine lubricant formulations combining organometallic friction modifiers and / or various organic friction modifiers and VI improving polymers are known. Thus, engine lubricating compositions which make it possible to achieve fuel savings (known as "fuel eco") can be formulated by the combination of GTL-type bases with organic fatty acid and polyol type organic friction modifiers. and polybutene-type VI improvers, ethylene propylene copolymers, polyacrylates or polymethacrylates, AB Block copolymers obtained by copolymerization of diene such as butadiene and isoprenes with vinyl aromatics such as styrene. Such compositions are disclosed, for example, in WO 2008/124191. Such bases, however, have the disadvantage of a high cost and it is desirable to develop an additivation to formulate fuel saving lubricants or fuel eco (FE) with bases mostly conventional. R: \ 31900 \ 31942 TFE \ 31942--100722_text depot bis.docx Organometallic friction modifiers can also be associated. The application EP 2078745 thus discloses a lubricating composition for petrol and diesel engines, associating molybdenum dithiocarbamates and zinc dithiophosphates, and making it possible to obtain fuel savings in vehicles equipped with these engines. These formulas, however, contain a high level of sulfur, metals, phosphorus that can be detrimental to particulate emissions and post-treatment systems. Eco-fueled motor lubricants comprising a mixture of organomolybdenum friction modifiers such as molybdenum dithiocarbamates, and organic friction modifiers such as monoesters of fatty acids and polyols are described in application WO 2004/053033. WO 93/21288 discloses FE motor lubricants also combining ethoxylated amine friction modifiers with partial esters of fatty acids and polyols, and VI improvers of polyester type, polymethacrylates, polyacrylates, polyolefins. Application EP 0955353 also describes fuel-oil motor lubricant formulas combining organomolybdenum friction modifiers (DTCMo) with ethoxylated fatty amine-type organic friction modifiers, optionally in combination with VI-improving polymers of polymethacrylate, polyolefin, styrene type. diene copolymers. The fuel savings achieved by the engine lubricant must be evaluated globally over an entire standard engine cycle representative of the average conditions of use.

However, a significant part of the energy losses occurs in the cold phase of the engine cycle, at startup. This is particularly true for urban vehicles, especially for new hybrid engines that operate with a stop and start system, where the engine is stopped and restarted a significant number of times.

There is therefore a need for engine lubricants to achieve fuel savings greater than or equivalent to existing formulas, and in particular on the cold phase of the engine cycle. The lubricant compositions according to the invention make it possible to achieve significant fuel savings, in particular in the cold-urban cycle, thanks to a combination of VI-improving polymers and specific friction modifiers. Brief Description of the Invention: The present invention relates to a lubricant composition comprising: (a) one or more base oils, (b) at least one a comb polymer formed of a polyalkyl (meth) acrylate main chain, and hydrocarbon side chains having at least 50 carbon atoms, (c) at least one nitrogen-containing organic friction modifier selected from fatty amines, optionally alkoxylated, fatty amides or imides obtained by condensation of fatty amines and carboxylic acids, alone or as a mixture, (d) Optionally, one or more organometallic friction modifiers of organomolybdenum type.

Preferably, the hydrocarbon side chains of the comb polymers (b) are obtained by polymerization or copolymerization of olefins, preferentially chosen from optionally substituted styrenes, and comprising from 8 to 17 carbon atoms, butadiene, added to 1-4. or 1-2, or the monomers of formula (I) X2 where X1 and X2 are independently either hydrogen or alkyl groups having from 1 to 18 carbon atoms. According to one embodiment, the comb polymers (b) are obtained by copolymerization of macromonomers of formula (II) OR 'R1 + AJ (A') + CH2CH2-OCC-CH2 nm with acrylic or methacrylic monomers of formula (III ): R 'O 30 H2C-CC-OR2 (III) Where:

Each R 'is independently hydrogen or methyl

R1 is an alkyl or aryl residue having from 1 to 6 carbon atoms; R1 is an alkyl residue having from 1 to 26 carbon atoms

A is formed by the 1,4-addition of butadiene, optionally substituted by alkyl groups comprising 1 to 6 carbon atoms, or by the vinyl addition of styrene, optionally substituted by alkyl groups comprising 1 to 6 atoms

of carbon,

A 'is formed by the addition of 1,2 butadiene optionally substituted with alkyl groups comprising 1 to 6 carbon atoms, or by the vinyl addition of styrene, optionally substituted with alkyl groups comprising 1 to 6 carbon atoms,

n and m are integers greater than or equal to zero, and n + m is an integer between 7 and 3000, preferably between 10 and 3000.

According to another embodiment, the comb polymers (b) are obtained by copolymerization of macromonomers of formula (IV) ## STR5 ## CH2-CH-HCH2-C-CH2-CH2-O-CC = CH2 PI q I r

X3 (IV) with acrylic or methacrylic monomers of formula (II): R 'O H2C = C-C-OR2 Where:

Each R 'is independently hydrogen or methyl

R1 is an alkyl or aryl residue having from 1 to 6 carbon atoms

R2 is an alkyl residue having from 1 to 26 carbon atoms

X1, X2, X3 are independently either hydrogen or alkyl groups having from 1 to 18 carbon atoms.

p, q, r are integers greater than or equal to zero, and p + q + r is an integer between 7 and 3000, preferably between 10 and 3000. According to one embodiment of the compositions according to the invention, at least one modifier Nitrogenous organic rubbing (c) is selected from fatty amines of formula (V): R: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx R4, n

Where R 3, R 4, n, R 5 are independently either hydrogen or aliphatic chains comprising from 1 to 150 carbon atoms, preferably from 1 to 32 carbon atoms, and at least one of the chains R3, R4, n, or R5 is a fatty aliphatic chain comprising at least 7 carbon atoms,

n is an integer greater than or equal to 1, preferably between 1 and 2. According to another embodiment of the compositions according to the invention, at least one nitrogen-containing organic friction modifier (c) is chosen from alkoxylated amines corresponding to in the formulas (VI) or (VII) below: ## STR1 ## (R7O) R6 HZ (ORs) R9-i (R80) qH Rio (Rs0) pH (VII)

Wherein R6 and R10 are, independently, fatty aliphatic chains, comprising between 7 and 150, preferably between 7 and 32 carbon atoms, preferably between 12 and 18 carbon atoms,

R7 and R8 are, independently, hydrocarbon radicals comprising from 2 to 6 carbon atoms, preferentially from 2 to 4, preferably 2 carbon atoms

R9 is a hydrocarbon radical comprising from 1 to 6 carbon atoms,

x, y, p, q and z are integers between 0 and 50, satisfying: 0 <x + y <(or equal) 50 and 0 <p + q + z <(or equal) 50. Preferably, when at least a nitrogen-containing organic friction modifier (c) is selected from ethoxylated amines, said friction modifier is selected from the diéthano-lamines of formula (VIII): R11 -N 's'''C2H4OH (VIII) Where R11 is a fatty aliphatic chain comprising from 7 to 150 carbon atoms, preferably from 7 to 32 carbon atoms, preferably from 12 to 18 carbon atoms. In another embodiment of the compositions according to the invention, at least one nitrogen-containing organic friction modifier (c) is chosen from amides or imides. fatty compounds obtained by condensation of a dicarboxylic acid of formula (IX) ## STR1 ## where R12 and R13 are independently hydrogen or a hydrocarbon group, or the hydrocarbon groups R12 and R13 form a ring, with an amine of formula (X) R14R15NH Where R14 and R15 independently represent hydrogen or an aliphatic chain comprising between 1 and 150 carbon atoms, preferably from 1 to 32 carbon atoms, preferably from 1 to 26 carbon atoms, and at least one of the chains R1 or R2 is a fatty aliphatic chain comprising at least 7 carbon atoms. According to a preferred embodiment, the lubricant compositions according to the invention comprise at least one nitrogen-containing organic friction modifier (c) as described above and at least one organometallic friction modifier (d).

Preferably, in the lubricant compositions according to the invention containing organometallic friction modifiers (d), these are chosen from dithiocarbamates, dithiophosphates, dithiophosphinates, xanthates and thioxanthates of molybdenum. Preferably, the organometallic friction modifier (d) is a molybdenum dithiocarbamate of formula (XI): wherein R 16, R 17, R 18, R 19 are alkyl chains having from 8 to 13 carbon atoms. Preferably, the lubricant compositions according to the invention comprise: from 65 to 90% by weight of one or more base oils (a), from 2 to 15% by weight of polymer (b), of from 0.01 to at 2% by weight of friction modifiers (c). In a particularly preferred manner, the lubricating compositions according to the invention comprise at least one isoparaffinic mineral base oil (a) obtained by hydroisomerization of a filler. n-paraffinic solvent from solvent dewaxing or catalytic dewaxing, or at least one isoparaffinic synthetic base oil (a) obtained by hydroisomerization of a paraffinic n load consisting of a Fisher Tropsh wax. According to one embodiment, the lubricant compositions according to the invention are of OW20 or OW30 grade according to the SAEJ300 classification. According to a particularly preferred embodiment, the lubricating compositions according to the invention are 4-stroke petrol or diesel engine oils of motor vehicles, preferably light vehicles, preferably diesel.

The present invention also relates to the use of lubricating compositions as described above for the lubrication of gasoline or diesel 4-stroke engines of light vehicles, preferably of hybrid vehicles. According to a preferred mode, this use is made in a diesel engine.

DETAILED DESCRIPTION: The lubricant compositions according to the invention make it possible to achieve fuel savings, in particular in the urban cold cycle, thanks to a specific combination of VI improving polymers and friction modifiers.

VI Improving Polymer (b): The VI improving polymers are compounds for minimizing the variations in viscosity deviation with temperature, i.e., to maintain an oil film sufficient to protect the parts in friction at high temperature, and preventing an excessive increase in viscosity when cold. Known viscosity index improvers are typically polyalkyl methacrylates (PMAs), polyacrylates, polyolefins, olefin copolymers (dienes) with vinyl aromatics (styrene). US Pat. Nos. 5,565,130 and 5,597,871 and the application US2008 / 0194443 describe, as VI-improving polymer, polymers having a comb-like structure formed by copolymerization of acrylate or methacrylate macromonomers comprising a hydrocarbon-based chain, for example of the olefin copolymer type, with acrylate or methacrylate monomers. Depending on whether the monomers are of the acrylate or methacrylate type, these polymers will be called polyacrylate (comb PA) or comb polymethacrylate (comb PMA) polymers, respectively. According to the IUPAC Compendium of Chemical Technology, 2nd Edition, 1997, a comb polymer is a polymer composed of comb macromolecules, which are macromolecules consisting of a main chain with multiple branch points of degree 3, each of which is the starting point of a linear side chain. This comb structure distinguishes the polymers of US Pat. Nos. 5,565,130 and 5,597,871 and of Application US2008 / 0194443 from polyacrylates and polymethacrylates (PMA) usually used as VI improvers in lubricant compositions of the prior art, in particular those described in applications EP 0955353 and WO 93/21288. The lubricant compositions according to the invention comprise, as VI-improving polymer, such a "comb polymer", or polymer with a comb structure, such as for example described in patents US 5,565,130 and US 5,597,871, and the application US2008 / 0194443 of the present application.

The lubricating compositions according to the invention thus contain, as VI-improving polymer, comb polyacrylates (comb PA) or comb polymethacrylates (comb PMA) which are comb polymers formed of a main chain polyalkyl (meth) acrylates, and long hydrocarbon side chains having at least 50 carbon atoms.

Preferentially, these hydrocarbon side chains have between 50 and 25,000 carbon atoms, preferably between 80 and 20000 carbon atoms, typically of the order of 10,000 carbon atoms.

According to a preferred embodiment, the hydrocarbon side chains are obtained by polymerization or copolymerization of olefins, for example styrene-type monomers, optionally substituted, and comprising from 8 to 17 carbon atoms, butadiene, added to 1-4 or 1-2, ethylene, propylene, isobutene and more generally monomers of formula (I): X 2 X-C CI-12 (I) Where X 1 and X 2 are independently either hydrogen or alkyl groups having 1 to 18 carbon atoms. According to one embodiment, the compositions according to the invention contain a comb-polymer obtained by copolymerization of macromonomers of formula (II) R: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx OR 'R1 + AJ (A '± CH2CH2-OCC = CH2 nm with acrylic or methacrylic monomers of formula (III): R' O H2C = CC-OR2 Where:

Each R 'is independently hydrogen or methyl

R1 is an alkyl or aryl residue having 1 to 6 carbon atoms R2 is an alkyl residue having 1 to 26 carbon atoms

A is formed by the 1,4-addition of butadiene, optionally substituted with

alkyl groups having 1 to 6 carbon atoms, or by the vinyl addition of styrene, optionally substituted by alkyl groups comprising 1 to 6 carbon atoms,

A 'is formed by the addition of 1,2 butadiene optionally substituted with alkyl groups having 1 to 6 carbon atoms, or by the addition

styrene vinyl, optionally substituted with alkyl groups having 1 to 6 carbon atoms,

n and m are integers greater than or equal to zero, and n + m is an integer between 7 and 3000, preferably between 10 and 3000.

According to another embodiment, the compositions according to the invention contain a comb polymer obtained by copolymerization of macromonomers of formula (IV) ## STR2 ## CH2-CH2-O-CC = CH2 X3 with acrylic or methacrylic monomers of formula (III): R 'O H2C = CC-OR2 Where: Each R' is independently hydrogen or a methyl Rl is an alkyl or aryl residue having 1 to 6 carbon atoms R2 is an alkyl residue having from 1 to 26 carbon atoms

X1, X2, X3 are independently either hydrogen or alkyl groups having from 1 to 18 carbon atoms. p, q, r are integers greater than or equal to zero, and p + q + r is an integer between 7 and 3000, preferably between 10 and 3000.

In the compositions according to the invention, these comb polymers are advantageously used in combination with other VI improving polymers well known to those skilled in the art. These well-known polymers are for example chosen from the category of hydrogenated styrene diene copolymers, for example hydrogenated styrene butadiene copolymers (SBH) or styrene isoprene, which are well known to those skilled in the art, preferably hydrogenated styrene butadiene. These latter improving polymers of VI, without having any influence on the fuel eco performance, nevertheless make it possible to provide the viscosity making it possible to formulate oils of grade 30. In the compositions according to the invention, the VI (b) improving polymers are typically present. at contents of between 2 and 20% by weight relative to the total weight of the composition, or between 2 and 15%, or between 5 and 15% by weight relative to the total weight of the composition. When the polymers (b) are used in combination with other VI improving polymers, the total VI improving polymer content is in the same ranges (between 2 and 20%, or between 2 and 15%, or between 5 and 10%). and 15% by weight of the VI-improving polymers relative to the total weight of the composition).

Friction Modifiers: Nitrogen Organic Scrub Modifier (c): The nitrogen-containing organic friction modifiers of the compositions according to the invention are fatty amines, optionally alkoxylated, or amine or imide-type fatty amine derivatives obtained by condensation of fatty amines with (di) carboxylic acids.

Fatty amines The fatty amines used in the lubricants according to the present invention are primary, secondary or tertiary monoamines, or polyamines, comprising one or more fatty chains. The term "fatty chain" denotes here noncyclic aliphatic hydrocarbon chains containing at least 7 carbon atoms, saturated or unsaturated, optionally branched. Fatty amines are mainly obtained from fatty acids (fatty-chain carboxylic acids), which are generally derived from the hydrolysis of triglycerides contained in oils. vegetable and animal, such as coconut, palm, olive, peanut, rapeseed, sunflower, soy, cotton, flax, beef tallow.

The fatty acids which make it possible to obtain the fatty amines of the compositions according to the invention generally comprise from 7 to 32 carbon atoms, preferably from 8 to 24 carbon atoms, preferably from 10 to 20, and preferably from 12 to 18 carbon atoms.

These are, for example, caprylic, pelargonic, capric, undecylenic, lauric, tridecylenic, myristic, pentadecyl, palmitic, margaric, stearic, isostearic, nonadecylic, arachic, henicosanoic, behenic, tricosanoic, lignoceric, pentacosanoic, cerotic, heptacosanoic, montanic, nonacosanoic, melissic, hentriacontanoic, laceroic or unsaturated fatty acids such as palmitoleic, oleic, erucic, nervonic, linoleic, a-linolenic, c-linolenic, di-homo-c-linolenic, arachidonic, eicosapentaenoic, docosahexanoic.

These acids are dehydrated in the presence of ammonia to give nitriles, which then undergo catalytic hydrogenation to lead to primary, secondary or tertiary amines.

The fatty amines used as compound (c) in the lubricating compositions according to the invention correspond to the general formula (V): R 4, n

Where R3, R4, n, R5 are independently either hydrogen or aliphatic chains

Comprising from 1 to 150 carbon atoms, preferably from 1 to 32 carbon atoms, and at least one of the R3, R4, n or R5 chains is a fatty aliphatic chain comprising at least 7 carbon atoms,

n is an integer greater than or equal to 1, preferably between 1 and 2.

The fatty amines used in the lubricants according to the invention are

Preferentially obtained from natural, plant or animal resources. Treatments that result in fatty amines from natural oils can result in mixtures of secondary and tertiary primary monoamines and polyamines. In the lubricating compositions according to the invention, mono or polyalkoxylated fatty amines, for example monoamines, may be used as compound or polyethoxylated, obtained from the fatty amines described above.

The alkoxylated amines used in the lubricant compositions according to the invention correspond, for example, to formulas (VI) and (VII) below: ## STR2 ## (R 7) (R 7 O) X H R 6 H 2 (ORs) 1 R 9 -i (R 80) qH Rio (Rs0) pH (VII)

Where R 6 and R 10 are, independently, fatty aliphatic chains, comprising between 7 and 150, preferably between 7 and 32 carbon atoms, preferably between 12 and 18 carbon atoms, R 7 and R 8 are, independently, hydrocarbon radicals comprising 2 to 6 carbon atoms, preferably 2 to 4, preferably 2 carbon atoms R 9 is a hydrocarbon radical comprising 1 to 6 carbon atoms, x, y, p, q and z are integers between 0 and 50, satisfying : 0 <x + y <(or equal) 50 and 20 0 <p + q + z <(or equal) 50. Preferentially, R5 and R9 are aliphatic fatty chains, optionally substituted with aryl groups. In a particularly preferred manner, they comprise between 7 and 30 carbon atoms, preferentially between 10 and 20, preferably between 12 and 18 carbon atoms. Preferentially, R6 and R7 are aliphatic chains, preferably alkyl, containing from 2 to 6 carbon atoms, preferably from 2 to 4, preferentially 2 carbon atoms. Preferentially, R8 is an aliphatic chain, preferably an alkyl chain, containing from 1 to 6 carbon atoms, preferably from 2 to 4, preferably 3 to 30 carbon atoms.

Particularly preferred compounds are diethanolamines of formula (VIII): ## STR1 ## C2H4OH R11 -N C2H4OH (VIII)

Where R 11 is an aliphatic chain containing from 7 to 150 carbon atoms, preferably from 7 to 32 carbon atoms, preferably from 12 to 18 carbon atoms

Fatty amides and imides: The nitrogen-containing organic friction modifiers (c) of the lubricating compositions according to the invention may be amides or imides obtained by condensation of the fatty amines described above and of carboxylic acids, such as, for example, oleylamides. , in particular primary oleylamides. According to one embodiment, the organic friction modifiers (c) are amides or imides obtained by condensation of fatty amines and of optionally hydroxylated aliphatic or aromatic dicarboxylic acids, such as for example malonic or succinic acids, malic, tartaric, phthalic, isophthalic, preferentially tartaric acid.

According to one embodiment, the organic friction modifiers (c) are fatty amides or imides obtained by condensation of a dicarboxylic acid of formula (IX) ## STR1 ## where R12 and R13 are independently hydrogen or a grouping wherein R14 and R15 independently represent hydrogen or an aliphatic chain comprising between 1 and 150 carbon atoms, preferably from 1 to 150 carbon atoms, preferably from 1 to 32 carbon atoms, preferably 1 to 26 carbon atoms, and at least one of the chains R1 or R2 is a fatty aliphatic chain comprising at least 7 carbon atoms. Such friction modifiers are described in US application 2006/0079413, paragraphs [0025] to [028]. R: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx Organometallic friction modifiers (d): Optionally, the lubricating compositions according to the invention may contain one or more organomolybdenum compound as a friction modifier. These compounds are well known to those skilled in the art. These are, for example compounds also containing sulfur or phosphorus, such as dithiophosphates, dithiocarbamates, dithiophosphinates, xanthates, thioxanthates of molybdenum molybdenum. Organomolybdenum compounds which are suitable for the lubricant compositions according to the present invention are for example described in the application EP 2,078,745, [0036] to [062].

In the compositions according to the invention, the nitrogen-containing organic friction modifiers (c) are typically present at contents of between 0.01 and 2% by weight relative to the total weight of the composition, or between 0.1 and 1 %, or between 0.3 and 0.8% by weight relative to the total weight of the composition. When the nitrogen organic friction modifiers (c) are used in combination with other organometallic friction modifiers (d), the total content of friction modifiers is in the same ranges (between 0.01 and 2%, or between 0.1 and 1%, or between 0.5 and 0.8% by weight of the friction modifiers relative to the total weight of the composition).

Base oils (a): The lubricant compositions according to the present invention comprise one or more base oils, generally representing at least 60% by weight of the lubricating compositions, generally at least 65% by weight, and up to 90% by weight and more.

The base oil (s) used in the compositions according to the present invention may be oils of mineral or synthetic origin of groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) as summarized herein. below, alone or mixed.

Saturated content Sulfur content Viscosity index Group I Mineral oils <90%> 0.03% 80 VI <120 Group II Oils> _90% 0.03% 80VI <120 hydrocracked Group III 90% 0.03% 120 Hydrocracked or hydro-isomerized oils Group IV PAO Polyalphaolefins Group V Esters and other bases not included in groups I to IV R: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx These oils may be oils of vegetable, animal or mineral origin. The mineral base oils according to the invention include all types of bases obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, desalphating, solvent dewaxing, hydrotreatment, hydrocracking and hydroisomerization, hydrofinishing. The base oils of the compositions according to the present invention may also be synthetic oils, such as certain esters of carboxylic acids and alcohols, or polyalphaolefins. The polyo-olefins used as base oils, for example, are obtained from monomers having from 4 to 32 carbon atoms (for example octene, decene), and have a viscosity at 100 ° C of between 1.5 and 15 Cst. Their weight average molecular weight is typically between 250 and 3000. Mixtures of synthetic and mineral oils may also be employed. Preferably, the lubricant compositions according to the invention are formulated with Group III and / or IV bases. According to one preferred embodiment, the lubricant compositions according to the invention comprise at least one isoparaffinic mineral base oil, obtained by hydroisomerization of an n-paraffinic charge, resulting from solvent dewaxing or catalytic dewaxing operations. Such bases are Group III mineral bases referred to as Group III + bases. According to another preferred embodiment, the lubricant compositions according to the invention comprise at least one isoparaffinic synthetic base oil, obtained by hydroisomerization of an n-paraffinic filler such as a Fisher Tropsh wax. According to a particularly preferred embodiment, the lubricant compositions according to the invention contain 65 to 90% by weight of such isoparaffinic bases. According to one embodiment, the lubricant compositions according to the invention exclusively contain so-called Group III + mineral bases or bases obtained by hydroisomerization of a Fisher Tropsh wax as a base oil, in a proportion of between 65 and 90%. in mass. Preferably, the compositions according to the present invention have a kinematic viscosity at 100 ° C. of between 5.6 and 16.3 Cst, measured by the ASTM D445 standard (grade SAE 20, 30 and 40), preferably between 9.3 and 12.5 Cst (grade 30).

According to a particularly preferred embodiment, the compositions according to the present invention are OW30 or OW20 grade multigrade oils according to the SAEJ300 classification. The compositions according to the present invention also preferably have a VI viscosity index greater than 130, preferably greater than 150, preferably greater than 160. Preferably, the compositions of the present invention also have a VI viscosity index greater than 130. Lubricants according to the invention are engine oils for petrol or diesel vehicles, preferably for diesel vehicles, preferably in accordance with the specifications ACEA C2 or JASO DL1 well known to those skilled in the art.

Other additives: The lubricant compositions according to the invention may also contain any type of additive adapted to their use. These additives can be added individually, or in the form of packets of additives, guaranteeing a certain level of performance to the lubricating compositions, as required, for example for a diesel lubricant ACEA (European car manufacturers) or JASO (Japan Automobile Standards Organization). ). These are for example and not limited to: Dispersants, generally representing between 5 and 8% by weight of the lubricating compositions. Dispersants such as succinimides, PIB (polyisobutene) succinimides, Mannich bases ensure the maintenance in suspension and evacuation of insoluble solid contaminants formed by the secondary oxidation products that are formed when the engine oil is in use. Antioxidants generally represent between 0.5 and 2% by weight of the lubricating compositions. Antioxidants delay the degradation of oils in service, which can result in the formation of deposits, the presence of sludge, or an increase in the viscosity of the oil. They act as free radical inhibitors or destroyers of hydroperoxides. Among the commonly used antioxidants are phenolic antioxidants, sterically hindered amines. Another class of antioxidants is that of oil-soluble copper compounds, for example copper thio or dithiophosphate, copper and carboxylic acid salts, copper dithiocarbamates, sulphonates, phenates, acetylacetonates. Copper salts I and II, succinic acid or anhydride are used. Antiwear additives, generally representing between 1 and 2% by weight of the lubricating compositions. The anti-wear additives protect the friction surfaces by forming a protective film adsorbed on these surfaces. The most commonly used is Zinc di thiophosphate or DTPZn. This category also contains various phosphorus, sulfur, nitrogen, chlorine and boron compounds. Detergents generally represent between 2 and 4% by weight of the lubricating compositions. Detergents are typically alkali metal or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, as well as the salts of phenates. They typically have a BN according to ASTM D2896 greater than 40, or 80 mg KOH / gram of detergent, and are most often overbased, with BN values typically of the order of 150 and more, or even 250 or 400 or more. (expressed as mg KOH per gram of detergent).

And also defoamers, pour point depressants, corrosion inhibitors ...

Examples: Preparation of oils: Several OW30 diesel engine oils were prepared from a diesel engine performance additive package to meet ACEA C2 / JASO DL1 specifications, including antioxidants. , corrosion inhibitors, dispersants, detergents, antiwear agents, pour point depressants, corrosion inhibitors.

The compositions (in% by weight) of these oils are given in Table 1 below: ABCDEF Base group III + 79.2 73.0 72.7 - - 79.9 Synthetic base - - - 72.8 72.3 - Package additives 11.9 12.2 12.2 12.2 12.2 12.4 Reducer of - - - 0.2 0.2 - flow point SBH 2.6 14.3 14.3 13.5 14.8 - Comb PMA 5.8 - - - - - PMA 6.7 Amide and Imide 0.5 0.5 0.5 0.5 0.5 1 Fat Tartaric Acid MoDTC - 0.3 0.3 - - (ppm Mo) (300 ppm) (300 ppm) Total 100.0 100.0 100.0 100.00 100.00 100.00 Table 1: Mass compositions of OW30 grade motor oils

Measurement of fuel consumption 25 Engine tests were used to evaluate the fuel savings achieved by a diesel engine whose engine is lubricated with these different oils. A 5W30 oil, comprising an ACEA Cl / JASO DL1 performance level additive package, a polyisoprene-enhanced polyisoprene-enhancing polymer formulated from Group III base oils serve as a reference for the test. Principle of the test: A Toyota Corolla Verso D4D Clean Power vehicle, equipped with a Common Rail 2AD injection engine, a Diesel Particulate-Nox reduction (DPNR) post-treatment system with 5th regeneration injector to lure (?) , placed in a B7 (?) environment, is subjected to a NEDC (New European Driving Cycle), also called MVEG (Motor Vehicle Emissions group) cycle. This cycle is designed to reproduce reproducibly the conditions encountered on European roads and is widely used to measure the fuel consumption and polluting emissions of vehicles. The characteristics of this cycle (velocity as a function of time) are given in figure 1. It includes a cold phase or cold urban phase (from 0 to 200 seconds), an intermediate phase or hot urban phase (from 200 to 725 seconds), a phase hot or extra urban phase (from 725 to 1200 seconds).

Implementation: The vehicle is placed on an E4 standard two-roll bench to reproducibly simulate the resistance encountered on the road due to aerodynamic drag and the mass of the vehicle. The tests are carried out with an ambient air temperature of 20 ° C, a hygrometry of 50%, a pressure of 1000 mbar. The calculation of consumption is done by a carbon balance after analysis of the exhaust gases. The fuel used for all tests is an EN590-B7 diesel. Results: Absolute fuel consumption is measured (in liters / 100 km), on the global cycle and per phase. The consumption differences (in%) with the reference passed immediately before the oil sample to be analyzed are also calculated.

The results are given in Table 2. Oil A is according to the invention. It contains as a friction modifier a mixture of amides and fatty imides of tartaric acid. It contains as an improvement polymer of VI PMA comb, and a smaller amount of SBH, intended to provide the viscosity necessary to obtain a grade 30 oil.

The oils B to F contain friction modifiers identical to the oils according to the invention, at comparable contents, but are formulated without a comb polymer. The amounts of VI improving polymer are adjusted to obtain the desired viscosimetric grade. R: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx The oil A according to the invention allows to save fuel compared to oils B, C, D, E, F, over the entire engine cycle and in particular in the cold phase and in the intermediate phase. A: \ 31900 \ 31942 TFE \ 31942--100722 text depot bis.docx Cold phase Intermediate phase Hot phase Total cy cons O Conso Dev / cons o Conso Dev / cons o Conso Dev / cons o Conso reference reference reference reference reference reference reference previous next previous previous previous previous previous 9,08 9,74 6,77% 7,97 8,25 3,39% 5,74 5,81 1,20% 6,67 6,86 9,62 9,74 1 , 23% 8.21 8.25 0.48% 5.94 5.81 -2.23% 6.92 6.86 9.39 9.71 3.29% 8.01 8.14 1.59% 5.73 5.84 1.88% 6.71 6.85 9.49 9.73 2.46% 8.18 8.38 2.38% 5.75 5.81 1.03% 6.78 6 , 90 9,43 9,71 2,88% 8,17 8,32 1,80% 5,76 5,78 0,34% 6,78 6,86 9,36 9,71 3,60% 8, 25 8,32 0,84% 5,78 5,78 0,00% 6,81 6,86 Table 2: fuel consumption 1942 TFE \ 31942--100722_text depot bis.docx

Claims (16)

REVENDICATIONS1. A lubricating composition comprising: (a) one or more base oils, (b) at least one comb polymer formed of a polyalkyl (meth) acrylate main chain, and hydrocarbon side chains having at least 50 carbon atoms, (c) ) At least one nitrogen-containing organic friction modifier selected from fatty amines, optionally alkoxylated, fatty amides or imides obtained by condensation of fatty amines and carboxylic acids, alone or as a mixture, (d) Optionally, one or more modifiers organometallic friction of organomolybdenum type. 2. Lubricating composition according to claim 1, wherein the hydrocarbon side chains of the comb polymers (b) are obtained by polymerization or copolymerization of olefins, preferably chosen from optionally substituted styrenes, and comprising from 8 to 17 carbon atoms, butadiene. , added to 1-4 or 1-2, or the monomers of formula (I) X2 Where X1 and X2 are independently either hydrogen or alkyl groups having from 1 to 18 carbon atoms. 25 3. Lubricating composition according to claim 1 or 2, wherein the comb polymers (b) are obtained by copolymerization of macromonomers of formula (II) ## STR2 ## Acrylic or methacrylic monomers of formula (III): wherein each R 'is independently hydrogen or methyl R1 is an alkyl or aryl residue having from 1 to 6 carbon atoms R: R 1 is an alkyl residue having from 1 to 26 carbon atoms A is formed by the addition of 1,4 butadiene, optionally substituted with alkyl groups having 1 to 6 carbon atoms, or by the vinyl addition of styrene, optionally substituted with alkyl groups comprising 1 to 6 carbon atoms, A 'is formed by the addition of 1,2 butadiene optionally substituted with alkyl groups having 1 to 6 carbon atoms, or by the vinyl addition of styrene ene, optionally substituted with alkyl groups having 1 to 6 carbon atoms, n and m are integers greater than or equal to zero, and n + m is an integer between 7 and 3000, preferably between 10 and 3000. 4. Lubricating composition according to claim 1 or 2 wherein the comb polymers (b) are obtained by copolymerization of macromonomers of formula (IV) ## STR2 ## Embedded image with acrylic or methacrylic monomers of formula (III): ## STR2 ## Where: R 'is independently hydrogen or methyl R.sub.1 is a alkyl or aryl residue having 1 to 6 carbon atoms R2 is an alkyl residue having 1 to 26 carbon atoms X1, X2, X3 are independently either hydrogen or alkyl groups having 1 to 18 carbon atoms. P, q, r are integers greater than or equal to zero, and p + q + r is an integer between 7 and 3000, preferably between 10 and 3000. 5. Lubricating composition according to one of claims 1 to 4 wherein at least one nitrogen organic friction modifier (c) is selected from fatty amines of formula (V): R: \ 31900 \ 31942 TFE \ 31942--101214 where R3, R4, n, R5 are independently either hydrogen or aliphatic chains comprising from 1 to 150 carbon atoms, R3 - (- N CH2 -) - R5 n (V) preferably from 1 to 32 carbon atoms, and at least one of the chains R3, R4, n, or R5 is a fatty aliphatic chain comprising at least 7 carbon atoms, n is an integer greater than or equal to 1, preferably between 1 and 2. 6. Lubricating composition according to one of claims 1 to 4, wherein at least one nitrogen-containing organic friction modifier (c) is chosen from alkoxylated amines corresponding to formulas (VI) or (VII) below: ## STR3 ## R6 (R5) R6 (R5) R6 (R6) where R6 and R10 are, independently, fatty aliphatic chains, comprising from 7 to 150, preferably from 7 to 150, preferably from 7 to 150; and 32 carbon atoms, preferably between 12 and 18 carbon atoms, R7 and R8 are, independently, hydrocarbon radicals comprising from 2 to 6 carbon atoms, preferably from 2 to 4, preferably 2 carbon atoms R9 is a radical hydrocarbon comprising 1 to 6 carbon atoms, x, y, p, q and z are integers between 0 and 50, satisfying: 0 <x + y <(or equal) 50 and 0 <p + q + z <( or equal) 50. 7. Lubricating composition according to claim 6, wherein at least one nitrogen-containing organic friction modifier (c) is chosen from diethanolamines of formula (VIII): ## STR2 ## Where R11 is a fatty aliphatic chain having from 7 to 150 carbon atoms, preferably from 7 to 32 carbon atoms, preferably from 12 to 18 carbon atoms. 8. Lubricating composition according to one of claims 1 to 4 wherein at least one nitrogenous organic friction modifier (c) is selected from fatty amides or imides obtained by condensation of a dicarboxylic acid of formula (IX) O R120 OH R130 Where R12 and R13 are independently hydrogen or a hydrocarbon group, or the hydrocarbon groups R12 and R13 form a ring, With an amine of formula (X) R14R15NH Where R14 and R15 independently represent hydrogen or an aliphatic chain comprising between 1 and 150 carbon atoms, preferably from 1 to 32 carbon atoms, preferably from 1 to 26 carbon atoms, and at least one of the chains R1 or R2 is a fatty aliphatic chain comprising at least 7 carbon atoms. 9. Lubricating composition according to one of claims 1 to 8 comprising at least one nitrogenous organic friction modifier (c) and at least one organometallic friction modifier (d). The lubricating composition of claim 9 wherein the organometallic friction modifiers (d) are selected from dithiocarbamates, dithiophosphates, dithiophosphinates, xanthates, thioxanthates of molybdenum. 25 11. Lubricating composition according to one of claims 9 to 10 wherein the organometallic friction modifier (d) is a molybdenum dithiocarbamate of formula (XI): ## STR1 ## Embedded image R16, R17, R18, R19 are alkyl chains having from 8 to 13 carbon atoms. R17, R19, R17, R18, R19 are alkyl chains having from 8 to 13 carbon atoms. 12. Lubricating composition according to one of claims 1 to 11 comprising: - from 65 to 90% by weight of one or more base oils (a), - from 2 to 15% by weight of polymer (b), - from 0.01 to 2% by weight of friction modifiers (c). 13. lubricating composition according to one of claims 1 to 12 comprising at least one isoparaffinic mineral base oil (a) obtained by hydroisomerization of an n-paraffinic feedstock from solvent dewaxing or catalytic dewaxing, or at least one isoparafflic synthetic base oil (a) obtained by hydroisomerization of a paraffinic feedstock consisting of a Fisher Tropsh wax. 14. Lubricating composition according to one of claims 1 to 13 which is grade OW20 or OW30 according to the classification SAEJ300. 15. Use of a lubricant composition according to one of claims 1 to 14 for the lubrication of gasoline or diesel 4-stroke engines of light vehicles, preferably hybrid vehicles. 16. Use according to claim 15 wherein the engine is a diesel engine. R: \ 31900 \ 31942 TFE \ 31942--101214 modified rev game.docx