EP3374477A1

EP3374477A1 - Lubricating compositions for preventing or reducing abnormal combustion in a motor vehicle engine

Info

Publication number: EP3374477A1
Application number: EP16798662.9A
Authority: EP
Inventors: Thomas Roussel
Original assignee: Total Marketing Services SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2015-11-12
Filing date: 2016-11-10
Publication date: 2018-09-19
Also published as: US20180371356A1; FR3043691A1; WO2017081116A1; CN108350382A

Abstract

The invention relates to the use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing or reducing abnormal combustion in a motor vehicle engine.

Description

LUBRICATING COMPOSITIONS FOR PREVENTING OR REDUCING ABNORMAL COMBUSTION IN A MOTOR VEHICLE ENGINE

The invention relates to the use of a lubricant composition for preventing or reducing abnormal combustion in a motor vehicle engine. More particularly, the invention relates to the use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing or reducing the abnormal combustion in a motor vehicle engine.

The present invention also relates to a method for preventing or reducing abnormal combustion in a motor vehicle engine, using this lubricant composition.

The present invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing the abnormal combustion of fuel in a motor vehicle engine.

Technological background

Under ideal conditions, normal combustion in a spark-ignition engine occurs when a mixture of fuel, and in particular fuel and air, is ignited in the combustion chamber inside the cylinder by the production of a fuel. spark from a spark plug. Such normal combustion is generally characterized by expanding the flame front through the combustion chamber in an orderly and controlled manner. However, in some cases, the air / fuel mixture may be prematurely ignited by a source of ignition prior to ignition by the spark of the spark plug, resulting in an abnormal combustion phenomenon known as pre-ignition. .

However, it is preferable to reduce or even eliminate this phenomenon of abnormal combustion, including pre-ignition as this usually results in the presence of a sharp increase in temperatures and pressures in the combustion chamber, and thus have an impact significant negative impact on the efficiency and overall performance of an engine. In addition, the phenomenon of abnormal combustion, including pre-ignition can cause significant damage cylinders, pistons, spark plugs and valves in the engine and in some cases can even lead to engine failure or even engine failure.

Recently, low-speed pre-ignition (LSPI) has been identified, particularly by car manufacturers, as a potential problem for smaller engines (or downsized engines). LSPI generally occurs at low speeds and high loads, and can cause serious damage to the pistons and / or cylinders.

Solutions for decreasing the calcium content or increasing the zinc dithiophosphate or molybdenum dithiocarbamate content in a lubricant have been described (Takeuchi et al, "Investigation of Engine Oil Effect on Abnormal Combustion in Turbocharged Direct Injection - Spark Ignition Engines, "SAE Int J. Fuels Lubr 5 (3): 1017-1024, 2012; Hirano et al," Investigation of Engine Oil Effect on Abnormal Combustion in Turbocharged Direct Injection - Spark Ignition Engines (Part 2), "SAE Technical Paper 2013-01 -2569, 2013). However, these solutions are still insufficient to significantly reduce pre-ignition and difficult to implement, especially in countries where a high level of basicity is required on fuels. In addition, problems of lubricant stability or compatibility with post-treatment systems are associated with these solutions.

The application WO 2015023559 describes a method for reducing the pre-ignition by adding, in a lubricant composition, an additive for retarding ignition, said additive being chosen from organic compounds comprising at least one aromatic nucleus. However, these light organic compounds could cause an excessive increase in lubricant volatility.

Knocking is another phenomenon of abnormal combustion that can occur in a spark ignition engine of vehicles, and more particularly in a spark ignition engine of motor vehicles and is due to the self-ignition of fuel upstream of the front flame in the combustion chamber.

This auto-ignition propagates at a very high speed in the combustion chamber and causes vibrations at high frequencies of the gaseous mass and thermal overload of the engine, which can lead to serious mechanical incidents. Solutions commonly used by engine manufacturers to avoid this phenomenon, such as reduced ignition timing, significantly reduce the efficiency of spark ignition engines.

Documents US2763613, US2898359 have notably described the use of anti-knock compounds selected from organometallic compounds, and more particularly ferrocene compounds in a lubricating composition. Furthermore, the document WO2004 / 101717 describes the use of organometallic compounds based on manganese in a lubricant composition to reduce the phenomenon of rattling in an engine.

However, the use of such organometallic compounds promotes deposits in the combustion chamber and can thus cause abnormal combustion such as hot-spot ignition which can cause significant mechanical failure. In addition, they may pose a risk to human health.

Thus it would be desirable to have a lubricant that can prevent or reduce the risk of abnormal combustion in a motor vehicle engine, and in particular the risk of pre-ignition, including the LSPI or the clatter in a motor vehicle engine .

An object of the present invention is therefore to provide compounds as well as a lubricating composition comprising these compounds which overcomes all or part of the aforementioned drawbacks.

Another object of the present invention is to provide a lubricant composition for preventing or reducing abnormal combustion in a motor vehicle engine and whose formulation is easy to implement.

Another object of the present invention is to provide a lubricant composition for preventing or reducing abnormal combustion in a motor vehicle engine while retaining satisfactory or improved lubrication properties.

Another object of the present invention is to provide a lubrication method for preventing or reducing abnormal combustion in a motor vehicle engine. Summary of the invention

The invention thus relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the abnormal combustion of the fuel in a motor vehicle engine.

Surprisingly, the Applicant has found that the presence of at least one fatty amine in a lubricant composition allows the lubricating composition, once implemented in an engine, to prevent or reduce the abnormal combustion of the fuel in a fuel. motor vehicle engine.

Thus, the present invention makes it possible to formulate lubricant compositions having both good stability and good properties for preventing or reducing the abnormal combustion of the fuel when used in a motor vehicle engine.

Advantageously, the lubricant compositions according to the invention have good properties for prevention or reduction of pre-ignition, and in particular of low-speed pre-ignition (LSPI) once implemented in a motor vehicle engine.

Advantageously, the lubricant compositions according to the invention have good pre-ignition prevention or reduction properties when used in a motor vehicle engine without the need to associate them with other technical solutions for preventing or preventing ignition. to reduce the pre-ignition, and in particular technical solutions requiring to reduce the calcium or magnesium content or causing an excessive increase in the volatility of the lubricant composition.

Advantageously, the lubricant compositions according to the invention have good properties for preventing or reducing knocking when used in a motor vehicle engine.

Advantageously, the lubricant compositions according to the invention have good properties for reducing or even suppressing the pinging phenomenon. once implemented in a motor vehicle engine without the need to add a high content of anti-rattling compound in the lubricant composition. Advantageously, the lubricant compositions according to the invention have good properties of reducing or even suppressing the knocking phenomenon once implemented in a motor vehicle engine without the need to add other anti-knock additives, and in particular no anti-knock additives selected from organometallic compounds.

Advantageously, the lubricant compositions according to the invention have good properties for preventing or reducing the abnormal combustion of the fuel when used in a motor vehicle engine and whose formulation is easy to implement.

Ri represents a saturated or unsaturated hydrocarbon group, linear or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom chosen from nitrogen, sulfur or oxygen,

R ₂ , R ₄ or R ₅ independently represents a hydrogen atom or a saturated or unsaturated hydrocarbon group, linear or branched, and optionally comprising at least one heteroatom chosen from nitrogen, sulfur or oxygen,

R ₃ represents a saturated or unsaturated hydrocarbon group, linear or branched, comprising one or more carbon atom (s), and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen, preferably oxygen,

N represents an integer greater than or equal to 1, more preferably between 1 and 10, even more preferably between 1 and 6, still advantageously representing 1, 2 or 3; a mixture of fatty polyalkylamines comprising one or more polyalkylamines of formulas (III) and / or (IV):

in which

R, identical or different, represents a linear or branched alkyl group comprising from 8 to 22 carbon atoms,

N and z, independently of each other, represent 0, 1, 2 or 3, and

• when z is greater than 0, o and p, independently of each other, represent 0, 1, 2 or 3,

said mixture comprising at least 3% by weight of branched compounds such that at least one of n or z is greater than or equal to 1, or of their derivatives, or

mixtures of fatty amines of formulas (I), (III) and / or (IV). Preferably, the fatty amine is of formula (I)

R 1 - [(NR ₂ ) -R ₃ ] n -NR ₄ R ₅ ,

(I)

in which,

R ₂ , R 4 or R ₅ independently represents a hydrogen atom or a linear or branched, saturated or unsaturated hydrocarbon group, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen,

n is greater than or equal to 0, preferably represents an integer greater than or equal to 1, more preferably between 1 and 10, still more preferably between 1 and 6, still advantageously represents 1, 2 or 3.

Preferably, the fatty amine is a mixture of fatty polyalkylamines comprising one or more polyalkylamines of formulas (III) and / or (IV):

in which

· N and z, independently of one another, represent 0, 1, 2 or 3, and

said mixture comprising at least 3% by weight of branched compounds such that at least one of n or z is greater than or equal to 1, or of their derivatives. In the context of the present invention, unsaturated alkyl is understood to mean an alkyl comprising at least one carbon-carbon double bond.

In another embodiment of the invention, the fatty amine is of formula (I) in which:

R 1 represents a linear or branched, saturated or unsaturated alkyl group comprising from 12 to 22 carbon atoms, preferably from 14 to 22 carbon atoms, and optionally at least one heteroatom chosen from nitrogen, sulfur or oxygen, and / or

R ₂ , R ₄ or R ₅ independently represents a hydrogen atom; a saturated or unsaturated, linear or branched alkyl group comprising between 1 and 22 carbon atoms, preferably between 14 and 22 carbon atoms, more preferably between 16 and 22 carbon atoms; or a group (R ₆ -O) _p -H in which R ₆ is a saturated alkyl group, linear or branched, comprising at least 2 carbon atoms, preferably between 2 and 6 carbon atoms, more preferably between 2 and 4 carbon atoms and p represents an integer greater than or equal to 1, preferably between 1 and 6, more preferably between 1 and 4, and / or

• R ₃ represents a saturated or unsaturated alkyl group, linear or branched, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms.

• n is 1, 2 or 3,

R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising from 12 to 20 carbon atoms, preferably from 14 to 20 carbon atoms, advantageously from 16 to 20 carbon atoms and optionally at least one heteroatom selected from 1 nitrogen, sulfur or oxygen,

R ₂ independently represents a hydrogen atom or a saturated, linear or branched alkyl group comprising from 1 to 20 carbon atoms, preferably from 16 to 20 carbon atoms, more preferably from 16 to 18 carbon atoms, R ₃ represents a saturated and linear alkyl group comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms,

R ₄ and R ₅ represent a hydrogen atom or a methyl group, preferably a hydrogen atom.

• n is equal to 3,

R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising from 12 to 20 carbon atoms, preferably from 14 to 20 carbon atoms, more preferably from 16 to 20 carbon atoms, and optionally at least one chosen heteroatom; among nitrogen, sulfur or oxygen,

R ₂ independently represents a hydrogen atom or a linear or branched, saturated alkyl group comprising from 16 to 18 carbon atoms,

R ₃ represents an ethyl or propyl group,

• R ₄ and R ₅ represent a hydrogen atom.

• n is 1, 2 or 3,

R 1 represents a linear or branched, saturated or unsaturated alkyl group comprising from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms,

R ₂ , R 4 and R ₅ independently represent a hydrogen atom or a group (R ₆ -O) _p -H in which R ₆ is a linear saturated alkyl group comprising between 2 and 6 carbon atoms, more preferably between 2 and 4 carbon atoms and p representing an integer between 1 and 6, more preferably between 1 and 4,

R ₃ represents a saturated and linear alkyl group comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms. In another embodiment of the invention, the fatty amine is of formula (I) in which:

• n is equal to 3,

R ₂ , R 4 and R ₅ independently represent a hydrogen atom or a group (R ₆ -O) _p -H in which R ₆ is a linear saturated alkyl group comprising between 2 and 4 carbon atoms and p representing an integer between 1 and 4,

• R ₃ represents an ethyl or propyl group.

In another embodiment of the invention, the fatty amine represents from 0.1 to 5% by weight, preferably from 0.1 to 3% by weight relative to the total weight of the lubricating composition.

In another embodiment of the invention, the fuel is mixed with air.

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the pre-ignition in a motor vehicle engine.

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing pre-ignition at low speed in a motor vehicle engine.

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing rattling in a motor vehicle engine.

The invention also relates to a method for preventing or reducing the abnormal combustion of the fuel in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above. above. The invention also relates to a method for preventing or reducing preignition in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above.

The invention also relates to a method for preventing or reducing pre-ignition at low speed in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above. above.

The invention also relates to a method for preventing or reducing rattling in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above.

The invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing the abnormal combustion of fuel in a motor vehicle engine.

The invention also relates to the use of a fatty amine in a lubricant composition to prevent or reduce pre-ignition in a motor vehicle engine.

The invention also relates to the use of a fatty amine in a lubricant composition to prevent or reduce pre-ignition at low speed in a motor vehicle engine.

The invention also relates to the use of a fatty amine in a lubricant composition to prevent or reduce rattling in a motor vehicle engine.

The invention thus relates to the use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the abnormal combustion of gas in a motor vehicle engine. Detailed description of the invention

The percentages given below correspond to percentages by mass of active ingredient.

The lubricating composition used according to the invention comprises at least one fatty amine.

The term "fatty amine" according to the invention means an amine of formula (I) comprising one or more hydrocarbon groups, saturated or unsaturated, linear or branched, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen, preferably oxygen.

In one embodiment of the invention, the fatty amine is of formula (I)

(I)

in which,

R ₂ , R 4 or R ₅ independently represents a hydrogen atom or a saturated or unsaturated hydrocarbon group, linear or branched, and optionally comprising at least one heteroatom chosen from nitrogen, sulfur or oxygen,

N is greater than or equal to 0, preferably represents an integer greater than or equal to 1, more preferably between 1 and 10, even more preferably between 1 and 6, still advantageously represents 1, 2 or 3. In a preferred embodiment of the invention, the fat lily is of formula (I) in which:

In a more preferred embodiment of the invention, the fatty amine is of formula (I) in which:

• n is 1, 2 or 3,

R ₂ independently represents a hydrogen atom or a saturated, linear or branched alkyl group comprising from 1 to 20 carbon atoms, preferably from 16 to 20 carbon atoms, more preferably from 16 to 18 carbon atoms,

R ₃ represents a saturated and linear alkyl group comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms, R ₄ and R ₅ represent a hydrogen atom or a methyl group, preferably a hydrogen atom.

Advantageously, the fatty amine is of formula (I) in which:

• n is equal to 3,

R ₂ independently represents a hydrogen atom or a saturated alkyl group, linear or branched, comprising from 16 to 18 carbon atoms,

R ₃ represents an ethyl or propyl group,

• R ₄ and R ₅ represent a hydrogen atom.

In another preferred embodiment of the invention, the fatty amine is of formula (I) in which:

• n is 1, 2 or 3,

R ₃ represents a saturated and linear alkyl group comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms.

• n is equal to 3, R 1 represents a linear or branched, saturated or unsaturated alkyl group comprising from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms,

• R ₃ represents an ethyl or propyl group.

In general, the fatty amines according to the invention are mainly obtained from carboxylic acids. These acids are dehydrated in the presence of ammonia to give nitriles, and then undergo catalytic hydrogenation to lead in particular to fatty amines.

For the purposes of the invention, the fatty amine of formula (I) is obtained from at least one carboxylic acid, preferably at least one fatty acid.

For the purposes of the invention, the alkyl group of the fatty amine has a number of carbon atoms corresponding to the number of carbon atoms of the carbon chain of the carboxylic acid, preferably corresponding to the number of carbon atoms. carbon of the carbon chain of the fatty acid

For the purposes of the invention, a same fatty amine of formula (I) may be substituted with several alkyl groups obtained from several identical or different carboxylic acids, preferably obtained from several identical or different fatty acids.

According to one particular embodiment of the invention, the alkyl group is obtained from fatty acid chosen from caprylic, pelargonic, capric, undecylenic, lauric, tridecylenic, myristic, pentadecylic, palmitic, margaric, stearic and nonadecylic acids. arachic, henicosanoic, behenic, tricosanoic, lignoceric, pentacosanoic, cerotic, heptacosanoic, montanic, nonacosanoic, melissic, hentriacontanoic, laceroic, and their derivatives or unsaturated fatty acids such as palmitoleic acid, oleic acid, erucic acid, nervonic acid, linoleic acid, -linolenic, c-linolenic, di-homo-c-linolenic, arachidonic, eicosapentaenoic, docosahexanoic, and their derivatives. Preferably, the fatty acids are derived from the hydrolysis of triglycerides present in vegetable and animal oils, such as coconut oil, palm oil, olive oil, peanut oil, rapeseed oil, sunflower oil, soya oil, of cotton, flax, beef tallow. Natural oils may have been genetically modified to enrich their content of certain fatty acids, for example rapeseed oil or oleic sunflower oil. In general, the fatty amine of formula (I) according to the invention is preferably obtained from natural, vegetable or animal resources. Treatments for producing fatty amines from natural oils can lead to mixtures of primary, secondary and tertiary polyamines.

According to a particular embodiment of the invention, when several fatty amines are used to prevent or reduce the abnormal combustion of the fuel in a motor vehicle engine, said fatty amines form a mixture of fatty amines comprising in variable proportions, all or a part of the compounds corresponding to the following formulas (Ia), (Ib), (Ie) and (Id):

R 1 - [(NR ₂ ) -R ₃ ] -NR ₄ R ₅ (Ib),

R 1 - [(NR ₂ ) -R ₃ ] ₂ -NR ₄ R 5 (le),

R 1 - [(NR ₂ ) -R ₃ ] 3 -NR ₄ R 5 (Id),

in which,

R 1 represents a saturated or unsaturated hydrocarbon group, linear or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom chosen from nitrogen, sulfur or oxygen,

R ₃ represents a saturated or unsaturated hydrocarbon group, linear or branched, comprising one or more carbon atom (s), and optionally comprising at least one heteroatom chosen from nitrogen, sulfur or oxygen, preferably oxygen; , The preferences and advantages for the definitions of the groups R 1, R ₂ , R ₃ , R ₄ , R ₅ and R ₆ of the fatty amines of formulas (Ia), (Ib), (Ic) and (Id) are as defined above for the fatty amine of formula (I) according to the invention.

In another embodiment of the invention, the mixture of fatty amines is in a purified form, that is to say comprising predominantly a single type of amine of formula (Ia), (Ib), ) or (Id), for example predominantly monoamines of formula (Ia), diamines of formula (Ib), triamines of formula (Ia) or still predominantly tetramines of formula (Id). In particular, the mixture of fatty amines comprises predominantly tetramines of formula (Id).

In another embodiment of the invention, the fatty amine mixture mainly comprises:

monoamines of formula (Ia), or

diamines of formula (Ib), or

triamines of formula (Ic), or

tetramines of formula (Ic),

wherein, the groups R 1, R ₂ , R 3, R ₄ , R 5 and R ₆ are as defined above.

In another particular embodiment of the invention, the fatty amine mixture mainly comprises monoamines of formula (Ia) in which:

R 1 represents a linear or branched, saturated or unsaturated alkyl group comprising from 12 to 20 carbon atoms, preferably from 14 to 20 carbon atoms, more preferably from 16 to 20 carbon atoms,

R ₄ and R ₅ independently represent a hydrogen atom or a linear or branched, saturated alkyl group comprising from 1 to 5 carbon atoms, preferably from 1 to 3 carbon atoms, more preferably a methyl group.

In another particular embodiment of the invention, the fatty amine mixture mainly comprises diamines of formula (Ib) in which:

Ri represents a linear or branched, saturated or unsaturated alkyl group comprising from 12 to 20 carbon atoms, preferentially from 14 to 20 carbon atoms, more preferably from 16 to 20 carbon atoms,

R ₂ represents a saturated, linear or branched alkyl group comprising from 1 to 5 carbon atoms, preferably from 1 to 3 carbon atoms, more preferably a methyl group,

R ₃ represents an ethyl or propyl group,

In a preferred embodiment of the invention, the mixture of fatty amines comprises mainly monoamines of formula RrNH ₂ (Ma), diamines of formula R 1 NR 1 -Raj-NH 2 (Mb), triamines of formula R ₁ - [(NR ₂ ) -R ₃ ] ₂ -NH ₂ (Mb), or tetramines of formula R ₁ - [(NR ₂ ) -R ₃ ] 3 -NN-1 ₂ (lld), wherein:

R 1 or R ₂ represents at least one alkyl group, saturated or unsaturated, obtained from a fatty acid derived from tallow fat, or soybean oil, or coconut oil, or from sunflower oil (oleic), and

• R ₃ represents a saturated or unsaturated hydrocarbon group, linear or branched, comprising at least 2 carbon atoms.

In the context of the invention, when R 1 or R ₂ represents a saturated alkyl group, said saturated alkyl is obtained from a saturated fatty acid or from a hydrogenated unsaturated fatty acid, in particular from the whole of these double bonds.

Advantageously, the mixture of fatty amines comprising predominantly tetramines of formula R [(NR ₂ ) -R ₃ ] 3 -NH ₂ (IId) is in the form:

at least one fatty amine of formula (IId) in which R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising from 14 to 16 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a linear saturated alkyl group comprising from 2 to 6 carbon atoms

at least one fatty amine of formula (IId) in which R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising at least 18 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a linear saturated alkyl group comprising from 2 to 6 carbon atoms, and

at least one fatty amine of formula (IId) in which R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising at least 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a linear saturated alkyl group comprising from 2 to 6 carbon atoms.

In particular, the mixture of fatty amines comprising predominantly tetramines of formula R ₁ - [(NR ₂ ) - R 3] 3 -NH ₂ (IId) is in the form:

at least one fatty amine of formula (IId) in which R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising from 14 to 16 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a saturated, linear alkyl group comprising from 2 to 6 carbon atoms,

at least one fatty amine of formula (IId) in which R 1 represents a saturated or unsaturated, linear or branched alkyl group comprising at least 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a saturated, linear alkyl group comprising from 2 to 6 carbon atoms,

the sum of the weight content of said fatty amines of formula (IIc) being greater than 90% relative to the weight of said mixture of fatty amines.

Advantageously, the mixture of fatty amines comprising predominantly tetramines of formula R ₁ - [(NR ₂ ) -R ₃ ] ₃ -NH ₂ (IId) is also in the form:

at least one fatty amine of formula (IId) in which R1 represents a linear or branched unsaturated alkyl group comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a linear saturated alkyl group comprising from 2 to 6 carbon atoms and at least one fatty amine of formula (IId) in which R1 represents a linear or branched saturated alkyl group comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a linear saturated alkyl group comprising from 2 to 6 carbon atoms.

at least one fatty amine of formula (IId) in which R1 represents a linear or branched unsaturated alkyl group comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a saturated, linear alkyl group comprising from 2 to 6 carbon atoms,

at least one fatty amine of formula (IId) in which R1 represents a linear or branched saturated alkyl group comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R ₂ represents a hydrogen atom; and R ₃ represents a saturated, linear alkyl group comprising from 2 to 6 carbon atoms,

the sum of the weight content of said fatty amines of formula (IId) being greater than 90% relative to the weight of said mixture of fatty amines.

Preferably, the fatty amine mixture does not include fatty amines other than fatty amines of formula (IId).

According to a particular embodiment of the invention, when a single fatty amine is used to prevent or reduce the abnormal combustion of the fuel in a motor vehicle engine, said fatty amine corresponds to one of the following formulas:

a monoamine of formula (IIa), or

a diamine of formula (Mb), or

a triamine of formula (Mb), or

a tetramine of formula (IIc),

in which,

Ri represents a linear or branched saturated hydrocarbon group comprising at least 14 carbon atoms, R ₂ independently represents a hydrogen atom or a saturated hydrocarbon group, linear or branched, comprising at least 14 carbon atoms,

• R ₃ represents a linear saturated hydrocarbon group comprising at least 2 carbon atoms.

In this embodiment, the fatty amine is preferably a tetramine of formula (IId) in which,

Ri represents a linear or branched saturated alkyl group comprising between 14 and 18 carbon atoms,

R ₂ independently represents a hydrogen atom or a saturated hydrocarbon group, linear or branched, comprising between 14 and 18 carbon atoms,

• R ₃ represents a saturated hydrocarbon group, linear, comprising between 2 and 6 carbon atoms.

In this embodiment, the fatty amine is advantageously a tetramine of formula (IId) in which,

Ri represents a linear or branched saturated alkyl group comprising between 16 and 18 carbon atoms,

R ₂ independently represents a hydrogen atom or a saturated hydrocarbon group, linear or branched, comprising between 16 and 18 carbon atoms,

• R ₃ represents an ethyl or propyl group.

Preferably, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the polyalkylamine mixtures comprise at least 5% by weight of compounds having a pure linear structure, since these compounds have been found to have an acceptable viscosity profile.

According to one embodiment, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the polyalkylamine mixtures comprise at least 4% by weight (% m / m), preferably at least 5% w / w, preferably at least 6% w / w, preferably more than 7% w / w, preferably more than 7.5% w / w, preferably more than 10% w / w, preferably more than 20 w / w% of branched compounds of which at least one of n or z is greater than or equal to 1.

For the products of formula (III), this means that for the branched products, n must be greater than or equal to 1.

Preferably, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), when n, o, p or z is equal to 0, the hydrogen atom present at the end of the chain is covalently bound to the corresponding secondary nitrogen atom.

Preferably, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the mixture comprises compounds of formulas (III) and / or (IV) in which n, o, p and z when they are different from 0, are equal to 1 or 2, preferably when n, o, p and z are different from 0 they are equal to 1.

According to a preferred embodiment, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the mixture essentially comprises compounds of formulas (III) and / or (IV) for which n, o, p or z are independently 0, 1 or 2, preferably n, o, p or z are independently 0 or 1.

According to a preferred embodiment, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the mixture essentially comprises compounds of formulas (III) and / or (IV) and their derivatives for wherein n, o, p and z are independently 0, 1 or 2, preferably n, o, p and z are independently 0 or 1.

The derivatives of the compounds of formulas (III) and / or (IV) are described below.

According to a preferred embodiment, each R group is, independently of one another, a linear or branched alkyl group comprising from 14 to 22 carbon atoms, preferably from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms. In general, the fatty amines of formula (III) and (IV) according to the invention are mainly obtained from carboxylic acids. These acids are dehydrated in the presence of ammonia to give nitriles, and then undergo catalytic hydrogenation to lead in particular to fatty amines.

For the purposes of the invention, the fatty amines of formula (III) and (IV) are obtained from at least one carboxylic acid, preferably at least one fatty acid.

Within the meaning of the invention, the alkyl group of the fatty amines of formula (III) and (IV) has a number of carbon atoms corresponding to the number of carbon atoms of the carbon chain of the carboxylic acid, preferably corresponding to the number of carbon atoms of the carbon chain of the fatty acid

Although the two R groups may be different, they are, according to a preferred embodiment, identical, such compounds being produced more economically. Regardless of whether they are identical or not, one or both R groups, independently, are derived from chemical or natural raw material such as natural oils and fats. In particular, if a natural raw material is used, it means that each group R can have a particular distribution in the length of the carbon chain. Suitably, R is derived from oil or fat of animal or vegetable origin such as tallow, coconut oil and palm oil. Since the preparation of the di-alkyl fatty polyalkylamines according to the invention comprises a hydrogenation step, it may be advantageous during the process for preparing the products of the invention to use hydrogenated R groups. Advantageously, the group R is a group of tallow hydrogen. Preferably, the group R of the raw material is unsaturated and is (partially) hydrogenated during the process for preparing the fatty polyalkylamine.

According to a particular embodiment of the invention, when the fatty amine is a mixture of polyalkylamines of formulas (III) and / or (IV), the alkyl group R is obtained from fatty acid chosen from caprylic acids. , pelargonic, capric, undecylenic, lauric, tridecylenic, myristic, pentadecylic, palmitic, margaric, stearic, nonadecylic, arachic, henicosanoic, behenic, tricosanoic, lignoceric, pentacosanoic, cerotic, heptacosanoic, montanic, nonacosanoic, melissic, hentriacontanoic, laceroic, and their derivatives or unsaturated fatty acids such as palmitoleic acid, oleic acid, erucic acid, nervonic acid, linoleic acid, α-linolenic acid, β-linolenic acid, di-homo-α-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexanoic acid, and derivatives thereof.

Preferably, the fatty acids are derived from the hydrolysis of triglycerides present in vegetable and animal oils, such as coconut oil, palm oil, olive oil, peanut oil, rapeseed oil, sunflower oil, soya oil, of cotton, flax, beef tallow. Natural oils may have been genetically modified to enrich their content of certain fatty acids, for example rapeseed oil or oleic sunflower oil.

The di-alkyl fatty polyalkylamine derivative compositions of formulas (III) and / or (IV) according to the invention comprise compounds for which one or more NH fragments of the fatty polyalkylamine of the invention are methylated, alkoxylated, or two. Such compounds have been found to have advantageous solubility, particularly in lubricating oils. Advantageously, the alkoxylated derivatives are butoxylated, propoxylated and / or ethoxylated. If two or more alkoxylating agents are used, they may be used in any order, for example EO-PO-EO, and the different aikoxy units may be polyhedral in nature and / or randomly present. Advantageously, a primary -NH ₂ group is alkoxylated with one or more alkylene oxides in a conventional manner to form a -NH-AO-H group, where AO represents one or more alkylene-oxy units. The -NH-AO-H group obtained can be further alkoxylated to form -N (AO-H) _{2 units} . In particular, when large Amounts of alkylene oxide (ie more than 8 moles of alkylene oxides per mole of polyalkylamine) are used, generally one or more of the secondary amines, if present, are alkoxylated.

According to one embodiment, all the primary and secondary amine functions of the di-alkyl polyamine of formulas (III) and / or (IV) are alkoxylated. According to another embodiment, the di-alkyl fatty polyalkylamines are derived by methylation of one or more NH functions in a manner known to those skilled in the art, for example by reaction with formic acid and formaldehyde. According to one embodiment, one or more OH functions of the alkoxylated fatty di-alkyl polyalkylamines are conventionally methylated.

However, since it may be more economical to prepare polyalkylamine mixtures of formula (IV), the polyalkylamine mixtures of formula (IV) are preferred. If appropriate, polyalkylamine mixtures of formulas (III) and / or (IV) are used.

The branched polyalkylamines of the invention may be produced by any synthetic route known to those skilled in the art. A conventional method of production can be from a diamine and involves two or more cycles, preferably two for economic reasons, each cycle having a cyanoethylation step and a hydrogenation step. This process is subsequently named a two-step process. In an alternative process, one equivalent of di-alkyl diamine can react in one step with two or more equivalents of acrylonitrile, followed by hydrogenation. In this case, optional additional cycles involving cyanoethylation and hydrogenation steps may be considered. Such a one-step process may be advantageous since it requires fewer intermediate steps. In order to increase the branching in the two-step process, an acid catalyst is used such as HCl or acetic acid. On the other hand, increasing the reaction temperature during cyanoethylation also makes it possible to increase the branching in this process. When carrying out a multi-circle process, the temperature of a subsequent cyanoethylation step is greater than the temperature of a preceding cyanoethylation step, making it possible to obtain a compound with the desired branching. According to one embodiment, more than one mole of acrylonitrile per mole of initial polyamine is used, which also makes it possible to increase the branching of the expected product to the desired level. Suitably and in order to maintain a homogeneous reaction mixture, a solvent is used. Preferred solvents include C _1-4 alcohols and C _2-4 diols. Preferably, ethanol is used because it allows a particular ease of handling. Surprisingly, it has been shown that the Ci _-4 alcohols and diols C ₂ -4 are not of single solvents but also have a co-catalytic activity in the cyanoethylation step. The amount of solvent employed may vary over a wide range. For economic reasons, the amount employed is preferably minimal. The amount of solvent, particularly in the cyanoethylation step, is preferably less than 50, 40, 30 or 25% by weight based on the liquid reaction mixture. The amount of solvent, in particular in the cyanoethylation step, is preferably greater than 0.1, 0.5, 1, 5 or 10% by weight relative to the liquid reaction mixture.

In one embodiment of the invention, the weight content of fatty amine, relative to the total weight of the lubricating composition, ranges from 0.1 to 5%, preferably from 0.1 to 3%, advantageously from 0.1 to 2%.

In a particular embodiment of the invention, the content by weight of fatty amine, relative to the total weight of the lubricating composition, ranges from 0.5 to 5%, preferably from 0.5 to 3%, advantageously from 0.5 to 2%.

The lubricating composition used according to the invention also comprises at least one base oil.

In general, the lubricant composition used according to the invention may comprise any type of mineral, synthetic or natural lubricating base oil, animal or vegetable, known to those skilled in the art.

The base oils used in the lubricant compositions according to the invention may be oils of mineral or synthetic origins belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) (Table A) or their mixtures. Content Content in Saturated Sulfur Viscosity Index (VI)

Group 1

<90%> 0.03% 80 <VI <120 Mineral oils

Group II

≥90% <0.03% 80 <VI <120 Hydrocracked oils

Group III

Hydrocracked oils ≥90% <0.03% ≥120 or hydro-isomerised

Group IV Polyalphaolefines (PAO)

Esters and other bases not included in groups 1

Group V

at IV

Table A

The mineral base oils according to the invention include all types of base oils obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, desalphating, solvent dewaxing, hydrotreatment, hydrocracking. , hydroisomerization and hydrofinition.

Mixtures of synthetic and mineral oils can also be used. There is generally no limitation on the use of different lubricating bases for producing the lubricating compositions used according to the invention, except that they must have properties, in particular viscosity, viscosity index, sulfur, oxidation resistance, adapted for use for engines or for vehicle transmissions.

The base oils of the lubricant compositions used according to the invention may also be chosen from synthetic oils, such as certain carboxylic acid esters and alcohols, and from polyalphaolefins. The polyalphaolefins used as base oils are, for example, obtained from monomers comprising from 4 to 32 carbon atoms, for example from octene or decene, and whose viscosity at 100 ° C. is between 1, 5 and 15 mm ² .s ^"1 according to ASTM D445 Their average molecular weight is generally between 250 and 3000 according to ASTM D5296.

Preferably, the base oils of the present invention are chosen from the above base oils whose aromatic content is between 0 and 45%, preferably between 0 and 30%. The aromatic content of the oils is measured according to UV Burdett method.

Advantageously, the lubricant composition used according to the invention comprises at least 50% by weight of base oils relative to the total mass of the composition.

More advantageously, the lubricant composition used according to the invention comprises at least 60% by weight, or even at least 70% by weight, of base oils relative to the total mass of the composition.

More particularly advantageously, the lubricant composition used according to the invention comprises from 60 to 99.5% by weight of base oils, preferably from 70 to 99.5% by weight of base oils, relative to the total mass of the composition.

Many additives can be used for this lubricant composition used according to the invention.

The preferred additives for the lubricant composition used according to the invention are selected from friction modifiers, detergents, antiwear additives, extreme pressure additives, viscosity index improvers, dispersants, antioxidants, improvers pour point, antifoams, thickeners and their mixtures.

Preferably, the lubricant composition used according to the invention comprises at least one antiwear additive, at least one extreme pressure additive or their mixtures.

Anti-wear additives and extreme pressure additives protect friction surfaces by forming a protective film adsorbed on these surfaces.

There is a wide variety of anti-wear additives. In a preferred manner for the lubricating composition according to the invention, the anti-wear additives are chosen from phosphosulfur additives such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates or ZnDTPs. The preferred compounds have the formula Zn ((SP (S) (OR ₇ ) (OR ₈ )) ₂ , in which R ₇ and R ₈ , which may be identical or different, independently represent an alkyl group, preferentially an alkyl group containing from 1 to 18 carbon atoms.

Amine phosphates are also anti-wear additives which can be used in the lubricating composition according to the invention. However, the phosphorus provided by these additives can act as a poison for the catalytic systems of automobiles because these additives are ash generators. These effects can be minimized by partially substituting amine phosphates with non-phosphorus additives, such as, for example, polysulfides, especially sulfur-containing olefins.

Advantageously, the lubricant composition according to the invention may comprise from 0.01 to 6% by weight, preferably from 0.05 to 4% by weight, more preferably from 0.1 to 2% by weight relative to the mass. total lubricating composition, anti-wear additives and extreme pressure additives.

Advantageously, the lubricant composition according to the invention may comprise at least one friction-modifying additive. The friction modifying additive may be chosen from a compound providing metal elements and an ash-free compound. Among the compounds providing metal elements, mention may be made of transition metal complexes such as Mo, Sb, Sn, Fe, Cu and Zn, the ligands of which may be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus. The ashless friction modifier additives are generally of organic origin and may be selected from monoesters of fatty acids and polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borate fatty epoxides; fatty amines or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group comprising from 10 to 24 carbon atoms.

Advantageously, the lubricant composition according to the invention may comprise from 0.01 to 2% by weight or from 0.01 to 5% by weight, preferably from 0.1 to 1.5% by weight or 0.1 at 2% by weight relative to the total mass of the lubricant composition, friction modifier additive. Advantageously, the lubricant composition according to the invention may comprise at least one antioxidant additive.

The antioxidant additive generally serves to retard the degradation of the lubricating composition in service. This degradation can notably result in the formation of deposits, the presence of sludge or an increase in the viscosity of the lubricant composition.

Antioxidant additives act in particular as radical inhibitors or destroyers of hydroperoxides. Among the antioxidant additives commonly used, mention may be made of antioxidant additives of phenolic type, antioxidant additives of amine type, antioxidant phosphosulfur additives. Some of these antioxidant additives, for example phosphosulfur antioxidant additives, can be ash generators. Phenolic antioxidant additives may be ash-free or may be in the form of neutral or basic metal salts. The antioxidant additives may especially be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted with at least one C ₁ -C ₁₂ alkyl group, Ν , Ν'-dialkyl-aryl diamines and mixtures thereof.

Preferably, according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group in which at least one vicinal carbon of the carbon bearing the alcohol function is substituted with at least one alkyl group containing ₁₀ carbon atoms, preferably an alkyl group containing CrC ₆ , preferably a C ₄ alkyl group, preferably by the ter-butyl group. Amino compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example aromatic amines of formula NR ₉ R ₁₀ wherein R ₉ represents an optionally substituted aliphatic or aromatic group, R ₁₀ represents an optionally substituted aromatic group, Ru represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R ₂ S (O) _z R 1 ₃ in which R ₁₂ represents an alkylene group or an alkenylene group, R ₁₃ represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

Sulfurized alkyl phenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

Another class of antioxidant additives is copper compounds, for example copper thio- or dithio-phosphates, copper and carboxylic acid salts, dithiocarbamates, sulphonates, phenates, copper acetylacetonates. Copper salts I and II, succinic acid or anhydride salts can also be used.

The lubricant composition according to the invention may contain all types of antioxidant additives known to those skilled in the art.

Advantageously, the lubricating composition comprises at least one ash-free antioxidant additive.

Also advantageously, the lubricating composition according to the invention comprises from 0.5 to 2% by weight relative to the total weight of the composition, of at least one antioxidant additive. The lubricant composition according to the invention may also comprise at least one detergent additive.

The detergent additives generally make it possible to reduce the formation of deposits on the surface of the metal parts by dissolving the secondary oxidation and combustion products.

The detergent additives that can be used in the lubricant composition according to the invention are generally known to those skilled in the art. The detergent additives may be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation may be a metal cation of an alkali metal or alkaline earth metal.

The detergent additives are preferably chosen from the alkali metal or alkaline earth metal salts of carboxylic acids, the sulphonates, the salicylates, the naphthenates and the phenate salts. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

These metal salts generally comprise the metal in stoichiometric amount or in excess, therefore in an amount greater than the stoichiometric amount. It is then overbased detergent additives; the excess metal bringing the overbased character to the detergent additive is then generally in the form of an oil insoluble metal salt, for example a carbonate, a hydroxide, an oxalate, an acetate, a glutamate, preferably a carbonate . Advantageously, the lubricant composition according to the invention may comprise from 2 to 4% by weight of detergent additive relative to the total mass of the lubricating composition.

Also advantageously, the lubricant composition according to the invention may also comprise at least one pour point depressant additive.

By slowing the formation of paraffin crystals, pour point depressant additives generally improve the cold behavior of the lubricant composition according to the invention.

As examples of pour point depressant additives, mention may be made of alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes and alkylated polystyrenes.

Advantageously, the lubricant composition according to the invention may also comprise at least one dispersing agent.

The dispersing agent may be chosen from Mannich bases, succinimides and their derivatives. Also advantageously, the lubricating composition according to the invention may comprise from 0.2 to 10% by weight of dispersing agent relative to the total mass of the lubricating composition.

The lubricating composition of the present invention may also comprise at least one viscosity index improving additive. Examples of additives improving the viscosity number include polymeric esters, homopolymers or copolymers, hydrogenated or non-hydrogenated, styrene, butadiene and isoprene, polyacrylates, polymethacrylates (PMA) or alternatively olefin copolymers, in particular ethylene / propylene copolymers. The lubricating composition according to the invention can be in various forms. The lubricant composition according to the invention may in particular be an anhydrous composition.

Preferably, this lubricating composition is not an emulsion.

The lubricating composition defined above is used to prevent or reduce the abnormal combustion of fuel in a motor vehicle engine.

Motor vehicle engine according to the invention more particularly means:

- gasoline engines but also gas and gasoline engines (dual fuel gas / gasoline engines) as well as engines running on gas and diesel (dual fuel gas / diesel engines);

- the engines of heavy goods vehicles.

Abnormal combustion means any phenomenon whereby all or part of the fuel mixture is ignited uncontrollably within the combustion chamber of a motor vehicle engine.

Abnormal combustion according to the invention more particularly means the following phenomena:

- pre-ignition, and in particular low-speed pre-ignition (LSPI),

- the rattling.

- the super-rattling or mega-rattling that may follow a pre-ignition event.

Pre-ignition according to the invention includes the phenomenon of low frequency vibration producing a sound effect of humming (or "Rumble" in English). By fuel according to the invention is more particularly meant gasoline or gas. In one embodiment of the invention, the fuel is mixed with air.

In a particular embodiment of the invention, the lubricant composition is used to prevent and / or reduce the abnormal combustion of the fuel resulting from the self-ignition of the lubricant composition during the fuel compression cycle of the motor vehicle engine .

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine to prevent and / or reduce pre-ignition in a motor vehicle engine.

All the characteristics and preferences relating to the lubricating composition, the fatty amine and the base oil described above also apply to this use.

Thus, the subject of the invention is also the use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the pre-ignition in a motor vehicle engine, the amine fat being selected from:

fatty amines of formula (I),

R 1 - [(NR ₂ ) -R ₃ ] n -NR ₄ R ₅ ,

(I)

a mixture of fatty polyalkylamines comprising one or more polyalkylamines of formulas (III) and / or (IV):

in which

N and z, independently of each other, represent 0, 1, 2 or 3, and

mixtures of fatty amines of formulas (I), (III) and / or (IV).

Preferably, the fatty amine is of formula (I),

R ₁ - [(NR ₂ ) -R ₃ ] _n -NR ₄ R 5,

(I)

The set of characteristics and preferences relating to Ri, R ₂ , R ₃ , R 4 and R ₅ described above also applies to this use.

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the low-speed pre-ignition (LSPI) in a motor vehicle engine . All the characteristics and preferences relating to the lubricating composition, the fatty amine and the base oil described above also apply to this use.

Thus, the subject of the invention is also the use of a lubricant composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the low speed pre-ignition (LSPI) in a motor. a motor vehicle, the fatty amine being chosen from:

fatty amines of formula (I)

R 1 - [(NR ₂ ) -R ₃ ] n -NR ₄ R ₅ ,

(I)

in which

n and z, independently of one another, represent 0, 1, 2 or 3, and when z is greater than 0, o and p, independently of each other, represent 0, 1, 2 or 3 said mixture comprising at least 3% by weight of branched compounds such that at least one of n or z is greater than or equal to 1, or of their derivatives, or

mixtures of fatty amines of formulas (I), (III) and / or (IV).

Preferably, the fatty amine is of formula (I),

(I)

The set of characteristics and preferences relating to R _1; R ₂ , R ₃ , R 4 and R ₅ described above also applies to this use.

The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine to prevent and / or reduce rattling in a motor vehicle engine.

All the characteristics and preferences relating to the lubricating composition, the fatty amine and the base oil described above also apply to this use. The invention also relates to the use of a lubricant composition comprising at least one base oil and at least one fatty amine to prevent and / or reduce the abnormal combustion of gas in a motor vehicle engine.

Motor vehicle engine is more particularly the engines of heavy vehicles operating on gas.

The invention also relates to a method for preventing or reducing the abnormal combustion of fuel in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricating composition as defined above. All the characteristics and preferences relating to the lubricating composition described above also apply to this process.

The invention also relates to a method for preventing or reducing the pre-ignition in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above. .

All the characteristics and preferences relating to the lubricating composition described above also apply to this process.

The invention also relates to a method for preventing or reducing the low-speed preignition (LSPI) in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricating composition as defined above.

The invention also relates to a method for preventing or reducing rattling in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricant composition as defined above. .

The invention also relates to a method for preventing or reducing the abnormal combustion of gas in a motor vehicle engine, said method comprising at least one step of contacting a mechanical part of the engine with a lubricating composition as defined above.

All the characteristics and preferences relating to the lubricating composition described above also apply to this process. The invention also relates to the use of a fatty amine in a lubricant composition for preventing or reducing the abnormal combustion of fuel in a motor vehicle engine.

All the characteristics and preferences relating to the lubricating composition and the fatty amine described above also apply to this use.

The invention also relates to the use of a fatty amine in a lubricant composition to prevent or reduce the low-speed pre-ignition b (LSPI) in a motor vehicle engine.

The invention also relates to the use of a fatty amine in a lubricant composition for preventing or reducing the abnormal combustion of gas in a motor vehicle engine.

Claims

Use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the abnormal combustion of the fuel in a motor vehicle engine, wherein the fatty amine is chosen from:

fatty amines of formula (I)

R 1 - [(NR ₂ ) -R ₃ ] n -NR ₄ R ₅ ,

(I)

in which,

N represents an integer greater than or equal to 1, more preferably between 1 and 10, even more preferably between 1 and 6, still advantageously representing 1, 2 or 3;

a mixture of one or more polyalkylamines of formulas (I II) and / or (IV):

in which

n and z, independently of one another, represent 0, 1, 2 or 3, and when z is greater than 0, o and p, independently of each other, represent 0, 1, 2 or 3

Said at least 3% by weight of branched compounds such as at least one of n or z is greater than or equal to 1, or of their derivatives.

Use according to claim 1, wherein:

R ₂ , R 4 or R ₅ independently represents a hydrogen atom; a saturated or unsaturated, linear or branched alkyl group comprising between 1 and 22 carbon atoms, preferably between 14 and 22 carbon atoms, more preferably between 16 and 22 carbon atoms; or a group (R ₆ -O) _p -H in which R ₆ is a saturated alkyl group, linear or branched, comprising at least 2 carbon atoms, preferably between 2 and 6 carbon atoms, more preferably between 2 and 4 carbon atoms and p represents an integer greater than or equal to 1, preferably between 1 and 6, more preferably between 1 and 4, and / or

Use according to claim 1 or 2, wherein:

• n is 1, 2 or 3,

R ₃ represents a saturated and linear alkyl group comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms,

Use according to one of Claims 1 to 3, in which:

• n is equal to 3,

R ₃ represents an ethyl or propyl group,

• R ₄ and R ₅ represent a hydrogen atom. Use according to claim 1 or 2, wherein:

• n is 1, 2 or 3,

Use according to one of Claims 1, 2 or 5, in which:

• n is equal to 3,

• R ₃ represents an ethyl or propyl group.

Use according to claim 1, wherein the mixture of polyalkylamines of formulas (III) and / or (IV) comprises at least 5% by weight of compounds having a pure linear structure.

Use according to claim 1 or 7, wherein the mixture of polyalkylamines of formulas (III) and / or (IV) comprises at least 4%, preferably at least 5%, preferably at least 6%, preferably more than 7%. %, preferably more than 7.5%, preferably more than 10%, preferably more than 20% by weight of branched compounds such as at least n or z is greater than or equal to 1.

9. Use according to any one of claims 1, 7 and 8, wherein the mixture of polyalkylamines of formulas (III) and / or (IV) comprises at least polyalkylamines of formulas (III) and / or (IV) such that when n, o, p and z are not equal to 0, they are equal to 1 or 2, preferably they are equal to 1.

10. Use according to any one of claims 1 and 7 to 9, wherein the mixture of polyalkylamines of formulas (III) and / or (IV) comprises at least polyalkylamines of formulas (III) and / or (IV) for wherein n, o, p or z are independently 0, 1 or 2, preferably independently 0 or 1. 11. Use according to any one of claims 1 and 7 to 10, wherein the mixture of polyalkylamines of formulas (III) and / or (IV) comprises at least polyalkylamines of formulas (III) and / or (IV) and their derivatives for which n, o, p or z independently represent 0, 1 or 2, preferably they represent independently 0 or 1.

12. Use according to any one of claims 1 to 1 1, wherein the mixture of fatty amines of formulas (I), (III) and / or (IV) represents from 0.1 to 15%, preferably from 0.5 to 10%, preferably 0.5 to 8% or 3 to 10% by weight relative to the total weight of the lubricating composition.

13. Use according to any one of the preceding claims, wherein the fatty amine represents from 0.1 to 5% by weight, preferably from 0.1 to 3% by weight relative to the total weight of the lubricating composition. 14. Use according to any one of the preceding claims, wherein the fuel is mixed with air.

15. Use of a lubricant composition comprising at least one base oil and at least one fatty amine to prevent and / or reduce pre-ignition in a motor vehicle engine.

16. Use of a lubricating composition comprising at least one base oil and at least one fatty amine for preventing and / or reducing the low-speed pre-ignition (LSPI) in a motor vehicle engine. 17. Use of a lubricant composition comprising at least one base oil and at least one fatty amine to prevent and / or reduce rattling in a motor vehicle engine.