US20180371356A1

US20180371356A1 - Lubricating compositions for preventing or reducing abnormal combustion in a motor vehicle engine

Info

Publication number: US20180371356A1
Application number: US15/775,304
Authority: US
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: 2018-12-27
Also published as: EP3374477A1; WO2017081116A1; FR3043691A1; CN108350382A

Abstract

Disclosed is a method for preventing and/or reducing abnormal combustion of fuel in a motor vehicle engine that includes the use of a lubricating composition including at least one base oil and at least one fatty amine.

Description

The invention relates to the use of a lubricating 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 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 that makes use of this lubricating 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 motor fuel in a motor vehicle engine.

TECHNOLOGICAL BACKGROUND

Under ideal conditions, a normal combustion in a spark ignition engine is brought about when a mixture of fossil fuel, and in particular motor fuel and air is ignited in the combustion chamber within the interior of the cylinder by the production of a spark from a spark plug. Such a normal combustion is generally characterised by the expansion of the flame front through the combustion chamber in an orderly and controlled manner.
However, in certain cases, the air/motor fuel mixture may be prematurely ignited by an ignition source before ignition by the spark of the spark plug, which leads to a phenomenon of abnormal combustion referred to as pre-ignition.
However, it is preferable to reduce or even eliminate this phenomenon of abnormal combustion, in particular of pre-ignition, as this results generally in the presence of a strong increase in temperature and pressure levels in the combustion chamber, and thus has a significant negative impact on the efficiency and overall performance of the engine. In addition, the phenomenon of abnormal combustion, and in particular of pre-ignition can cause significant damage to the cylinders, pistons, spark plugs and valves in the engine and in certain cases, could even lead to engine failure or indeed to engine break down.
Recently, Low Speed Pre-Ignition (or “LSPI” as per the accepted English terminology) has been identified, in particular by automobile manufacturers as a potential problem for small-sized engines (or downsized engines). The LSPI phenomenon generally occurs at low speeds and high loads, and can lead to serious damage to the pistons and/or to the cylinders.
Solutions that consist of decreasing the calcium content or increasing the content of zinc dithiophosphate or molybdenum dithiocarbamate 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, to date these solutions continue to be insufficient in order to significantly reduce pre-ignition and remain difficult to effectively implement, in particular in countries where a high level of alkalinity is required for motor fuels. Furthermore, problems related to stability of lubricants or compatibility with post-treatment systems are associated with these solutions.
The patent application WO 2015023559 describes a method for reducing pre-ignition by the addition, in a lubricating composition, of an additive that makes it possible to delay the ignition, the said additive being selected from among organic compounds comprising at least one aromatic ring. However, these light organic compounds could result in an excessive increase in the volatility of the lubricant.
Knocking is another abnormal combustion phenomenon that can occur in a spark-ignition engine of vehicles, and more particularly in a spark ignition engine of motor vehicles and which is due to self-ignition of the fuel upstream of the flame front in the combustion chamber.
This self-ignition spreads at very high speed within the combustion chamber and causes vibrations at high frequencies of the gas mass and the thermal overloading of the engine that could rise to the level of serious mechanical incidents or problems.
The solutions commonly used by motorists in order to prevent this phenomenon, such as reducing the spark advance, significantly reduce the performance of spark ignition engines.
The documents U.S. Pat. No. 2,763,613 and U.S. Pat. No. 2,898,359 have in particular described the use of anti-knock compounds selected from among organometallic compounds, and more particularly ferrocene-like compounds in a lubricating composition.
Furthermore, the document WO2004/101717 describes the use of manganese based organometallic compounds in a lubricating composition for reducing the phenomenon of knocking in an engine.
However, the use of such organometallic compounds promotes deposits in the combustion chamber and can thus result in abnormal combustion phenomena such as hot spot ignition that can cause significant mechanical failures. In addition, they may present a risk to human health.
Thus it would be desirable to have a lubricant that is able to prevent or reduce the risk of abnormal combustion in a motor vehicle engine, and in particular the risk of pre-ignition, including LSPI or even knocking in a motor vehicle engine.
One object of the present invention is therefore to provide compounds as well as a lubricating composition that comprises these compounds which overcome the aforementioned drawbacks in whole or part.
Another object of the present invention is to provide a lubricating composition that makes it possible to prevent or reduce abnormal combustion in a motor vehicle engine and the formulation of which is easy to implement.
Another object of the present invention is to provide a lubricating composition that makes it possible to prevent or reduce abnormal combustion in a motor vehicle engine while also retaining the satisfactory or even improved lubrication properties.
Another object of the present invention is to provide a lubrication method that makes it possible to prevent or reduce abnormal combustion in a motor vehicle engine.

SUMMARY OF THE INVENTION

The object of 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 motor fuel in a motor vehicle engine.
In a surprising manner, the Applicant has found that the presence of at least one fatty amine in a lubricating composition allows for the lubricating composition, upon operational application thereof in an engine, to prevent or reduce the abnormal combustion of motor fuel in a motor vehicle engine.
Thus the present invention makes it possible to formulate lubricating compositions that present both good stability and good properties for prevention or reduction of abnormal combustion of motor fuel upon operational application thereof in a motor vehicle engine.
Advantageously, the lubricating compositions according to the invention present good properties for prevention or reduction of pre-ignition, and in particular low speed pre-ignition (LSPI), upon operational application thereof in a motor vehicle engine.
Advantageously, the lubricating compositions according to the invention present good properties for prevention or reduction of pre-ignition upon operational application thereof in a motor vehicle engine, without the need to combine them with other technical solutions that make it possible to prevent or reduce pre-ignition, and in particular with technical solutions that necessitate reducing the calcium or magnesium content or that result in an excessive increase in the volatility of the lubricating composition.
Advantageously, the lubricating compositions according to the invention present good properties for prevention or reduction of knocking upon operational application thereof in a motor vehicle engine.
Advantageously, the lubricating compositions according to the invention present good properties for reduction or even elimination of the phenomenon of knocking upon operational application thereof in a motor vehicle engine without the need to add a high content of anti-knock compound in the lubricating composition.
Advantageously, the lubricating compositions according to the invention present good properties for reduction or even elimination of the phenomenon of knocking upon operational application thereof in a motor vehicle engine without the need to add other anti-knock additives, and in particular any anti-knock additives selected from among organometallic compounds.
Advantageously, the lubricating compositions according to the invention present good properties for prevention or reduction of the abnormal combustion of motor fuel, upon operational application thereof in a motor vehicle engine and the formulation thereof is easy to implement.
In one embodiment of the invention, the fatty amine is selected from among:

- fatty amines having the formula (I)

R₁—[(NR₂)—R₃]_n—NR₄R₅ (I)

- wherein
  - R₁represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₂, R₄or R₅independently represents, a hydrogen atom or a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained 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 that is greater than or equal to 1, more preferably comprised between 1 and 10, even more preferably between 1 and 6, indeed advantageously represents 1, 2 or 3;
  - a mixture of fatty polyalkylamines comprising one or more polyalkylamines having the formulas (III) and/or (IV):

- wherein
  - R, being either identical or different, represents an alkyl group, which is linear straight-chained or branched, comprising from 8 to 22 carbon atoms;
  - 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 one another, represent 0, 1, 2 or 3;
- the 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 derivatives thereof; or
  - mixtures of fatty amines having the formulas (I), (III) and/or (IV).

Preferably the fatty amine is of the formula (I)
R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)

- wherein
  - R₁represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₂, R₄or R₅independently represents, a hydrogen atom or a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained 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 is greater than or equal to 0, preferably represents an integer that is greater than or equal to 1, more preferably comprised between 1 and 10, even more preferably between 1 and 6, indeed advantageously represents 1, 2 or 3.
Preferably, the fatty amine is a mixture of fatty polyalkylamines comprising one or more polyalkylamines having the formulas (III) and/or (IV):

- wherein
  - R, being either identical or different, represents an alkyl group, which is linear straight-chained or branched, comprising from 8 to 22 carbon atoms;
  - 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 one another, represent 0, 1, 2 or 3;

the 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 derivatives thereof.
In the context of this present invention the term unsaturated alkyl is understood to mean an alkyl that comprises at least one carbon-carbon double bond.
In one other embodiment of the invention, the fatty amine is of the formula (I) wherein:

- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 22 carbon atoms, preferably from 14 to 22 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen, and/or
- R₂, R₄or R₅independently represents, a hydrogen atom; a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 22 carbon atoms, preferably between 14 and 22 carbon atoms, more preferably between 16 and 22 carbon atoms; or a (R₆—O)_p—H group, wherein R₆is a saturated alkyl group, which is linear straight-chained 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 that is greater than or equal to 1, preferably comprised between 1 and 6, more preferably comprised between 1 and 4 and/or
  - R₃represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms.

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

- n is equal to 1, 2 or 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, 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 nitrogen, sulfur or oxygen;
- R₂independently represents a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 20 carbon atoms, preferably from 16 to 20 carbon atoms, more preferably from 16 to 18 carbon atoms;
- R₃represents a saturated and linear alkyl group, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms;
- R₄and R₅represent a hydrogen atom or a methyl group, preferably a hydrogen atom.

- n is equal to 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, 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 heteroatom selected from nitrogen, sulfur or oxygen;
- R₂independently represents a hydrogen atom, or a saturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 18 carbon atoms;
- R₃represents an ethyl or propyl group;
- R₄and R₅represent a hydrogen atom.

- n is equal to 1, 2 or 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms;
- R₂, R₄and R₅independently represents, a hydrogen atom or a (R₆—O)_p—H group, wherein R₆is a saturated linear alkyl group, comprising between 2 and 6 carbon atoms, more preferably between 2 and 4 carbon atoms, and with p representing an integer comprised between 1 and 6, more preferably comprised between 1 and 4;
- R₃represents 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;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms;
- R₂, R₄and R₅independently represents, a hydrogen atom or a (R₆—O)_p—H group, wherein R₆is a saturated linear alkyl group, comprising between 2 and 4 carbon atoms, and with p representing an integer comprised between 1 and 4;
- R₃represents an ethyl or propyl group.

In one other embodiment of the invention, the fatty amine represents from 0.1 to 5% by weight, preferably from 0.1 to 3% by weight in relation to the total weight of the lubricating composition.
In one other embodiment of the invention, the motor fuel is mixed with air.
The invention also 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 pre-ignition in a motor vehicle engine.
The invention also 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 low speed pre-ignition in a motor vehicle engine.
The invention also 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 knocking in a motor vehicle engine.
The invention also relates to a method for preventing or reducing abnormal combustion of motor fuel in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
The invention also relates to a method for preventing or reducing pre-ignition in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
The invention also relates to a method for preventing or reducing low speed pre-ignition in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
The invention also relates to a method for preventing or reducing the knocking in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
The invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing the abnormal combustion of motor fuel in a motor vehicle engine.
The invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing pre-ignition in a motor vehicle engine.
The invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing low speed pre-ignition in a motor vehicle engine.
The invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing the knocking in a motor vehicle engine.
The object of 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 abnormal combustion of the gas in a motor vehicle engine.

DETAILED DESCRIPTION OF THE INVENTION

The percentages indicated here below correspond to the percentages by weight of active material.
The lubricating composition used according to the invention comprises at least one fatty amine.
The term “fatty amine” according to the invention, is used to refer to an amine having the formula (I) that comprises one or more saturated or unsaturated hydrocarbon groups, which is linear straight-chained or branched, and optionally comprises at least one heteroatom selected from nitrogen, sulfur or oxygen, preferably oxygen.
In one embodiment of the invention, the fatty amine is of the formula (I)
R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)

- wherein
  - R₁represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₂, R₄or R₅independently represents, a hydrogen atom, or a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising or more carbon atom(s), and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen, preferably oxygen;
  - n is greater than or equal to 0, preferably represents an integer that is greater than or equal to 1, more preferably comprised between 1 and 10, even more preferably between 1 and 6, indeed advantageously represents 1, 2 or 3.

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

- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 22 carbon atoms, preferably from 14 to 22 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen, and/or
- R₂, R₄or R₅independently represents, a hydrogen atom; a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 22 carbon atoms, preferably between 14 and 22 carbon atoms, more preferably between 16 and 22 carbon atoms; or a (R₆—O)_p—H group, wherein R₆is a saturated alkyl group, which is linear straight-chained or branched, comprising at least 2 carbon atoms, preferably between 2 to 6 carbon atoms, more preferably between 2 and 4 carbon atoms and p represents an integer that is greater than or equal to 1, preferably comprised between 1 and 6, more preferably comprised between 1 and 4; and/or
- R₃represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms.

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

- n is equal to 1, 2 or 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, 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 nitrogen, sulfur or oxygen;
- R₂independently represents a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 20 carbon atoms, preferably from 16 to 20 carbon atoms, more preferably from 16 to 18 carbon atoms;
- R₃represents a saturated and linear alkyl group, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms;
- R₄and R₅represent a hydrogen atom or a methyl group, preferably a hydrogen atom.

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

- n is equal to 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, 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 heteroatom selected from nitrogen, sulfur or oxygen;
- R₂independently represents a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 18 carbon atoms;
- R₃represents an ethyl or propyl group;
- R₄and R₅represent a hydrogen atom.

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

- n is equal to 1, 2 or 3;
- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 20 carbon atoms, advantageously from 16 to 20 carbon atoms;
- R₂, R₄and R₅independently represents, a hydrogen atom or a (R₆—O)_p—H group, wherein R₆is a saturated linear alkyl group, comprising between 2 and 6 carbon atoms, more preferably between 2 and 4 carbon atoms, and with p representing an integer comprised between 1 and 6, more preferably comprised between 1 and 4;
- R₃represents a saturated and linear alkyl group, comprising between 2 and 6 carbon atoms, preferably between 2 and 4 carbon atoms.

In a general manner, the fatty amines according to the invention are mainly obtained from carboxylic acids. These acids are dehydrated in the presence of ammonia in order to give nitriles, and then subjected to a catalytic hydrogenation process so as to yield in particular fatty amines.
Pursuant to the scope and context of the invention, the fatty amine having the formula (I) is obtained from at least one carboxylic acid, preferably from at least one fatty acid.
Pursuant to the scope and context of the invention, the alkyl group of the fatty amine presents a number of carbon atoms that corresponds to the number of carbon atoms of the carbon chain of the carboxylic acid, and preferably corresponds to the number of carbon atoms of the carbon chain of the fatty acid.
Pursuant to the scope and context of the invention, a same given fatty amine having the formula (I) may be substituted with a plurality of alkyl groups obtained from a plurality of carboxylic acids, which are identical or different, preferably obtained from a plurality of fatty acids, which are identical or different.
According to one particular embodiment of the invention, the alkyl group is obtained from a fatty acid selected from among caprylic acid, pelargonic acid, capric acid, undecylenic acid, lauric acid, tridecylenic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecyl acid, arachic acid, heneicosanoic acid, behenic acid, tricosanoic acid, lignoceric acid, pentacosanoic acid, cerotic acid, heptacosanoic acid, montanic acid, nonacosanoic acid, melissic acid, hentriacontanoic acid, laceroic acid, and derivatives thereof, or unsaturated fatty acids such as palmitoleic acid, oleic acid, erucic acid, nervonic acid, linoleic acid, a-linolenic acid, c-linolenic acid, di-homo-c-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and derivatives thereof.
Preferably, the fatty acids are derived from the hydrolysis of triglycerides found in plant and animal oils, such as coconut oil, palm oil, olive oil, peanut oil, rapeseed oil, sunflower oil, soybean oil, cotton seed oil, flax seed oil, beef tallow. The natural oils may have been genetically modified so as to enrich their content of certain fatty acids, for example rapeseed oil or oleic sunflower oil.
In a general manner, the fatty amine having the formula (I) according to the invention is preferably obtained from natural, plant or animal resources. The treatment processes that make it possible to obtain fatty amines from natural oils may lead to mixtures of primary, secondary and tertiary polyamines.
According to one particular embodiment of the invention, when a plurality of fatty amines are used to prevent or reduce abnormal combustion of motor fuel in a motor vehicle engine, the said fatty amines form a mixture of fatty amines comprising in variable proportions, all or part of the compounds having the formulas (Ia), (Ib), (Ic) and (Id) below:
R₁—NR₄R₅ (Ia);
R₁—[(NR₂)—R₃]—NR₄R₅ (Ib);
R₁—[(NR₂)—R₃]₂—NR₄R₅ (Ic);
R₁—[(NR₂)—R₃]₃—NR₄R₅ (Id);

- wherein;
  - R₁represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 12 carbon atoms, and optionally at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₂, R₄or R₅independently represents, a hydrogen atom or a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen;
  - R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising one or more carbon atom(s), and optionally comprising at least one heteroatom selected from nitrogen, sulfur or oxygen, preferably oxygen;

The preferences and advantages for the definitions of the groups R₁, R₂, R₃, R₄, R₅and R₆of the fatty amines having the formulas (Ia), (Ib), (Ic) and (Id) are as defined here above for the fatty amine having the formula (I) according to the invention.
In one other 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 having the formula (Ia), (Ib), (Ic) or (Id), for example predominantly monoamines having the formula (Ia), diamines having the formula (Ib), triamines having the formula (Ic), or even predominantly tetramines having the formula (Id). In particular, the mixture of fatty amines comprises predominantly tetramines having the formula (Id).
In one other embodiment of the invention, the mixture of fatty amines predominantly comprises:

- monoamines having the formula (Ia); or
- diamines having the formula (Ib); or
- triamines having the formula (Ic); or
- tetramines having the formula (Ic);

wherein the groups R₁, R₂, R₃, R₄, R₅and R₆are as defined here above.
In another particular embodiment of the invention, the mixture of fatty amines comprises predominantly monoamines having the formula (Ia) wherein:

- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 20 carbon atoms, preferably from 14 to 20 carbon atoms, more preferably from 16 to 20 carbon atoms;
- R₄and R₅independently represent a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, 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 mixture of fatty amines predominantly comprises diamines having the formula (Ib) wherein:

- R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 20 carbon atoms, preferably from 14 to 20 carbon atoms, more preferably from 16 to 20 carbon atoms;
- R₂represents a saturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 5 carbon atoms, preferably from 1 to 3 carbon atoms, more preferably a methyl group;
- R₃represents an ethyl or propyl group;
- R₄and R₅independently represent a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 5 carbon atoms, preferably from 1 to 3 carbon atoms, more preferably a methyl group.

In one preferred embodiment of the invention, the mixture of fatty amines predominantly includes monoamines having the formula R₁—NH₂(IIa), diamines having the formula R₁—[(NR₂)—R₃]—NH₂(IIb), triamines having the formula R₁—[(NR₂)—R3]₂NH₂(IIb), or tetramines having the formula R₁—[(NR₂)—R3]₃-NH₂(IId), wherein:

- R₁or R₂represents at least one saturated or unsaturated alkyl group, obtained from a fatty acid derived from tallow fat, or soybean oil, or coconut oil, or (oleic) sunflower oil; and
- R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 2 carbon atoms.

Pursuant to the scope and context of the invention, when R₁or R₂represents a saturated alkyl group, the said saturated alkyl is obtained from a saturated fatty acid or from an unsaturated fatty acid which has been subjected to a hydrogenation process, in particular of all of these double bonds.
Advantageously, the mixture of fatty amines comprising predominantly tetramines having the formula R₁—[(NR₂)—R3]₃-NH₂(IId) is present in the form:
of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 16 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms;

- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising at least 18 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms; and
- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising at least 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms.

In particular, the mixture of fatty amines comprising predominantly tetramines having the formula R₁—[(NR₂)—R3]₃-NH₂(IId) is present in the form:

- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 16 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms;
- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising at least 18 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms; and
- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising at least 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms;

the sum total of the content by weight of the said fatty amines having the formula (IIc) being greater than 90% in relation to the weight of the said mixture of fatty amines.
Advantageously, the mixture of fatty amines comprising predominantly tetra amines having the formula R₁—[(NR₂)—R3]₃-NH₂(IId) is also present in the form:

- of at least one fatty amine having the formula (IId) wherein R₁represents a unsaturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 20 carbon atoms, preferably 18 to 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms; and
- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms.

In particular, the mixture of fatty amines comprising predominantly tetra amines having the formula R₁—[(NR₂)—R3]₃-NH₂(IId) is present in the form:

- of at least one fatty amine having the formula (IId) wherein R₁represents a unsaturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms;
- of at least one fatty amine having the formula (IId) wherein R₁represents a saturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 20 carbon atoms, preferably from 18 to 20 carbon atoms; R₂represents a hydrogen atom; and R₃represents a saturated linear alkyl group, comprising from 2 to 6 carbon atoms;

the sum total of the content by weight of the said fatty amines having the formula (IId) being greater than 90% in relation to the weight of the said mixture of fatty amines.
Preferably the mixture of fatty amines does not include fatty amines other than fatty amines having the formula (IId).
According to one particular embodiment of the invention, when only one fatty amine is used for preventing or reducing abnormal combustion of motor fuel in a motor vehicle engine, the said fatty amine has one of the following formulas:

- a monoamine having the formula (IIa); or
- a diamine having the formula (IIb); or
- a triamine having the formula (IIb); or
- a tetra amine having the formula (IIc),

wherein
R₁represents a saturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 14 carbon atoms;

- R₂independently represents a hydrogen atom or a saturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 14 carbon atoms;
- R₃represents a saturated linear hydrocarbon group, comprising at least 2 carbon of carbon.

In this embodiment, the fatty amine preferably is a tetra amine having the formula (IId) wherein

- R₁represents a saturated alkyl group, which is linear straight-chained or branched, comprising between 14 and 18 carbon atoms;
- R₂independently represents a hydrogen atom, hydrogen or a saturated hydrocarbon group, which is linear straight-chained or branched, comprising between 14 and 18 carbon atoms;
- R₃represents a saturated linear hydrocarbon group comprising between 2 and 6 carbon atoms.

In this embodiment, the fatty amine is advantageously a tetra amine having the formula (IId) wherein,

- R₁represents a saturated alkyl group, which is linear straight-chained or branched, comprising between 16 and 18 carbon atoms;
- R₂independently represents a hydrogen atom, or a saturated hydrocarbon group, which is linear straight-chained or branched, comprising between 16 and 18 carbon atoms;
- R₃represents an ethyl or propyl group.

In a preferred manner, when the fatty amine is a mixture of polyalkylamines having the formulas (III) and/or (IV), the mixtures of polyalkylamines comprise at least 5% by weight of compounds having a pure linear structure, given that these compounds have been found to have an acceptable viscosity profile.
According to one embodiment, when the fatty amine is a mixture of polyalkylamines having the formulas (III) and/or (IV), the mixtures of polyalkylamines comprise at least 4% by weight (% w/w), 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 having the 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 having the 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 having the formulas (III) and/or (IV), the mixture comprises compounds having the formulas (III) and/or (IV) in which n, o, p and z, when they are other than 0, are equal to 1 or 2, preferably, when n, o, p and z are other than 0 they are equal to 1.
According to one preferred embodiment, when the fatty amine is a mixture of polyalkylamines having the formulas (III) and/or (IV), the mixture consists essentially of compounds having the formulas (III) and/or (IV) for which n, o, p, or z independently represent 0, 1 or 2, preferably n, o, p, or z independently represent 0 or 1.
According to one preferred embodiment, when the fatty amine is a mixture of polyalkylamines having the formulas (III) and/or (IV), the mixture consists essentially of compounds having the formulas (III) and/or (IV) and derivatives thereof for which n, o, p and z independently represent 0, 1 or 2, preferably, n, o, p and z independently represent 0 or 1.
The derivatives of the compounds having the formulas (III) and/or (IV) are described here below.
According to one preferred embodiment, each group R is, independently of each other, an alkyl group, which is linear straight-chained or branched, and comprises from 14 to 22 carbon atoms, preferably from 14 to 20 carbon atoms, preferably from 16 to 20 carbon atoms.
In a general manner, the fatty amines having the formula (III) and (IV) according to the invention are primarily obtained from carboxylic acids. These acids are dehydrated in the presence of ammonia to give nitriles, and then subjected to s catalytic hydrogenation process in order to yield in particular fatty amines.
Pursuant to the scope and context of the invention, the fatty amines having the formula (III) and (IV) are obtained from at least one carboxylic acid, preferably from at least one fatty acid.
Pursuant to the scope and context of the invention, the alkyl group of the fatty amines having the formula (III) and (IV) presents a number of carbon atoms that corresponds to the number of carbon atoms of the carbon chain of the carboxylic acid, and preferably corresponds to the number of carbon atoms of the carbon chain of the fatty acid.
Pursuant to the scope and context of the invention, a same given fatty amine having the formula (I) may be substituted with a plurality of alkyl groups obtained from a plurality of carboxylic acids, which are identical or different, preferably obtained from a plurality of fatty acids, which are identical or different.
Pursuant to the scope and context of the invention, a same given fatty amine having the formula (I) may be substituted with a plurality of alkyl groups obtained from a plurality of carboxylic acids, which are identical or different, preferably obtained from a plurality of fatty acids, which are identical or different.
Although the two R groups may be different, they are, according to one preferred embodiment, identical, such compounds being produced in a more economical manner. Regardless of whether they are identical or not, one or both of the R groups, independently, are derived from chemical or natural raw materials such as natural oils and fats. In particular, if a natural raw material is used, this means that each R group may have a particular distribution along the length of the carbon chain. In an appropriate manner, R is derived from oil or fat of animal or plant origin such as tallow, coconut oil, and palm oil. Since the preparation of di-alkyl fatty polyalkylamines according to the invention includes a hydrogenation step, it may be advantageous, during the preparation method for preparing the products of the invention to use hydrogenated R groups. In an advantageous manner, the R group is a hydrogenated tallow group. Preferably, the R group of the starting material is unsaturated and is (partially) hydrogenated during the method for preparation of the fatty polyalkylamine.
According to one particular embodiment of the invention, when the fatty amine is a mixture of polyalkyl amines having the formulas (III) and/or (IV), the alkyl group R is obtained from a fatty acid selected from among caprylic acid, pelargonic acid, capric acid, undecylenic acid, lauric acid, tridecylenic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecyl acid, arachic acid, heneicosanoic acid, behenic acid, tricosanoic acid, lignoceric acid, pentacosanoic acid, cerotic acid, heptacosanoic acid, montanic acid, nonacosanoic acid, melissic acid, hentriacontanoic acid, laceroic acid, and derivatives thereof, or unsaturated fatty acids such as palmitoleic acid, oleic acid, erucic acid, nervonic acid, linoleic acid, a-linolenic acid, c-linolenic acid, di-homo-c-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and derivatives thereof.
Preferably the fatty acids are derived from the hydrolysis of triglycerides found in plant and animal oils, such as coconut oil, palm oil, olive oil, peanut oil, rapeseed oil, sunflower oil, soybean oil, cotton seed oil, flax seed oil, beef tallow. The natural oils may have been genetically modified so as to enrich their content of certain fatty acids, for example rapeseed oil or oleic sunflower oil.
The compositions of derivatives of di-alkyl fatty polyalkylamines having the formulas (III) and/or (IV) according to the invention include compounds for which one or more NH moieties of the fatty polyalkylamine of the invention are methylates, alkoxylates, or both. It has been discovered that such compounds possess an advantageous solubility, in particular in lubricating oils. In an advantageous manner, the alkoxylated derivatives are butoxylates, propoxylates and/or ethoxylates. If two or more alkoxylating agents are used, they may be used in any order, for example EO-PO-EO, and the different alkoxy units may be polyhedral in nature and/or be present in random fashion. In an advantageous manner, a primary —NH₂group is alkoxylated with one or more alkylene oxides in a conventional manner in order to form a —NH-AO-H group, where AO represents one or more alkylene-oxy units. The —NH-AO-H group obtained in addition may be alkoxylated in order to form —N(AO-H)₂units. In particular, when large quantities of alkylene oxide (ie more than 8 moles of alkylene oxide per mole of polyalkylamine) are used, in general one or more secondary amines, if present, are alkoxylated.
According to one embodiment, all of the primary and secondary amine functions of the di-alkyl polyamine having the formulas (III) and/or (IV) are alkoxylated. According to one other embodiment, the di-alkyl fatty polyalkylamines are derived by methylation of one or more NH functions in a manner known to the person skilled in the art, for example by reaction with formic acid and formaldehyde. According to one embodiment, one or more OH functions of the di-alkyl alkoxylated fatty polyalkylamines are methylated in a conventional manner.
However, since it may be more economical to prepare mixtures of polyalkylamines having the formula (IV), the mixtures of polyalkylamines having the formula (IV) are preferred. If appropriate, mixtures of polyalkylamine having the formulas (III) and/or (IV) are used.
The branched polyalkylamines of the invention may be produced by any route of synthesis known to the person skilled in the art. A conventional method of production may be based on a diamine and involves two or more cycles, preferably two for economic reasons, each cycle comprising of a step of cyanoethylation and a step of hydrogenation. This process is subsequently referred to as the two-step process. In an alternative method, one equivalent of di-alkyl diamine may be reacted in one single step with two or more equivalents of acrylonitrile, followed by hydrogenation. In this case, optional additional cycles involving steps of cyanoethylation and hydrogenation may be envisaged. Such a one-step process may be advantageous because it necessitates 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. Furthermore, increasing of the reaction temperature during the cyanoethylation also makes it possible to increase the branching in this method. When carrying out a multi-cycle method, the temperature of a subsequent step of cyanoethylation is higher than the temperature of a preceding step of cyanoethylation, thereby 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. In an appropriate manner and in order to maintain a homogeneous reaction mixture, a solvent is used. The solvents preferred include C_1-4alcohols and C_2-4diols. In a preferred manner, ethanol is used because it provides for a particular ease of handling. In a surprising manner, it has been shown that the C_1-4alcohols and the C_2-4diols are not simple solvents but also have a co-catalytic activity during the step of cyanoethylation. The quantity of solvent employed may vary in accordance with a wide range. For economic reasons, the quantity employed is preferably minimal. The quantity of solvent, in particular in the step of cyanoethylation, is preferably less than 50, 40, 30 or 25% by weight in relation to the liquid reaction mixture. The quantity of solvent, in particular in the step of cyanoethylation is preferably greater than 0.1, 0.5, 1, 5 or 10% by weight in relation to the liquid reaction mixture.
In one embodiment of the invention, the content by weight of fatty amine, in relation 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 one particular embodiment of the invention, the content by weight of fatty amine, in relation 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 a general manner, the lubricating composition used according to the invention may comprise of any type of lubricating base oil derived from mineral, synthetic or natural, animal or plant sources, known to the person skilled in the art.
The base oils used in the lubricating compositions according to the invention may be oils of mineral or synthetic origin belonging to the Groups I to V according to the classes defined in the American Petroleum Institute (API) classification (or equivalents thereof according to the Association Technique de L′Industrie Européenne des Lubrifiants/Technical Association of the European Lubricants Industry (ATIEL) classification) (Table A) or mixtures thereof.

TABLE A

Saturates	Sulfur	Viscosity Index
Content	Content	(VI)

Group I	<90%	>0.03%	80 ≤ VI < 120
Mineral Oils
Group II	≥90%	≤0.03%	80 ≤ VI < 120
Hydrocracked Oils
Group III	≥90%	≤0.03%	≥120
Hydrocracked Or
Hydro-Isomerised Oils

Group IV	Polyalphaolefin (PAO)
Group V	Esters and Other Bases not included in Groups
	I to IV

The mineral base oils according to the invention include all types of base oils obtained by means of atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerisation, and hydrofinishing.
Mixtures of synthetic and mineral oils may also be used.
There is generally no limitation with respect to the use of various different base oils for producing the lubricating compositions according to the invention, other than that they must have properties, in particular as regards viscosity, viscosity index, sulfur content, and oxidation resistance, that are suitable for use in engines or for vehicle transmissions.
The base oils of the lubricating compositions used according to the invention may also be selected from among synthetic oils such as certain carboxylic acid esters and alcohol esters, 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 whereof the viscosity at 100° C. is comprised between 1.5 and 15 mm²·s⁻¹in accordance with the American Society for Testing and Materials standard ASTM D445. Their average molecular weight is generally comprised between 250 and 3000 in accordance with the ASTM D5296 standard.
In a preferred manner, the base oils of the present invention are selected from the base oils mentioned here above whereof the aromatic content is comprised between 0 and 45%, preferably between 0 and 30%. The aromatic content of the oils is measured according to the Burdett UV method.
In an advantageous manner, the lubricating composition used according to the invention comprises at least 50% by weight of base oils in relation to the total weight of the composition.
In a more advantageous manner, the lubricating composition used according to the invention comprises at least 60% by weight, or even at least 70% by weight, of base oils in relation to the total weight of the composition.
In a particularly more advantageous manner, the lubricating 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, in relation to the total weight of the composition.
A number of additives may be used for this lubricating composition used according to the invention.
The preferred additives for the lubricating composition used according to the invention are selected from among friction modifiers, detergents, anti-wear additives, extreme pressure additives, viscosity index improvers/enhancers, dispersants, antioxidants, pour point improvers, anti-foaming agents, thickeners and mixtures thereof.
In a preferred manner, the lubricating composition used according to the invention comprises at least one anti-wear additive, at least one extreme pressure additive or mixtures thereof.
The anti-wear additives and extreme pressure additives protect the surfaces in frictional contact by the formation of a protective film that is adsorbed on these surfaces.
There exists a wide variety of anti-wear additives. In a preferred manner, for the lubricating composition according to the invention, the anti-wear additives are selected from among phospho-sulfurised additives such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates or ZnDTP. The preferred compounds are those having the formula Zn((SP(S)(OR₇)(OR₈))₂, wherein R₇and R₈, which may be identical or different, independently represent an alkyl group, preferably an alkyl group having from 1 to 18 carbon atoms.
The amine phosphates are also anti-wear additives that may be employed in the lubricating composition according to the invention. However, the phosphorus provided by these additives may act as poison for the catalytic systems of the automobiles because these additives are prone to generating ashes. It is possible to minimise these effects by partially substituting the amine phosphates with additives that do not contribute any phosphorus, such as, for example, polysulfides, in particular sulfurised olefins.
In an advantageous manner, the lubricating 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 in relation to the total weight of the lubricating composition, of anti-wear additives and extreme pressure additives.
In an advantageous manner, the lubricating composition according to the invention may comprise at least one friction modifier additive. The friction modifier additive may be selected from a compound that provides metal elements and a compound free of ashes. Among the compounds providing metal elements, mention may be made of transition metal complexes such as Mo, Sb, Sn, Fe, Cu, Zn whose ligands may be hydrocarbon compounds containing atoms of oxygen, nitrogen, sulfur or phosphorus. The friction modifier additives that are ash-free are usually of organic origin and may be selected from among monoesters of fatty acids and of polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borated fatty epoxides; fatty amines, or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group having from 10 to 24 carbon atoms.
In an advantageous manner, the lubricating 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 from 0.1 to 2% by weight in relation to the total weight of the lubricating composition, of friction modifier additive.
In an advantageous manner, the lubricating composition according to the invention may comprise at least one antioxidant additive.
The antioxidant additive generally provides the means to delay the degradation of the lubricating composition in service. This degradation may in particular be reflected in the formation of deposits, by the presence of sludge or by an increase in the viscosity of the lubricating composition.
The antioxidant additives act in particular as free radical inhibitors or destroyers of hydroperoxides. Among the types of antioxidant additives commonly used, mention may be made of phenolic antioxidant additives, amine antioxidant additives, phosphorosulphur antioxidant additives. Certain of these antioxidant additives, such as phosphorosulphur antioxidant additives may be prone to generating ashes. The phenolic antioxidant additives may be ash-free or indeed in the form of neutral or basic metal salts. The antioxidant additives may be selected from among sterically hindered phenols, sterically hindered phenolic esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C₁-C₁₂alkyl group, N,N′-dialkyl-aryl diamines and mixtures thereof.
Preferably according to the invention, the sterically hindered phenols are selected from among compounds comprising a phenol group in which at least one carbon atom that is vicinal to the carbon bearing the alcohol function is substituted by at least one C₁-C₁₀alkyl group, preferably a C₁-C₆alkyl group, preferably a C₄alkyl group, preferably by the tert-butyl group.
Amine compounds are another class of antioxidant additives that may be used, possibly in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example, aromatic amines having the formula NR₉R₁₀R₁₁wherein R₉represents an aliphatic group or an aromatic group, possibly substituted, R₁₀represents an aromatic group, possibly substituted, R₁₁represents a hydrogen atom, an alkyl group, an aryl group, or a group having the formula R₁₂S(O)_zR₁₃wherein R₁₂represents an alkylene group or an alkenylene group, R₁₃represents an alkyl group, an alkenyl group or an aryl group, and z represents 0, 1 or 2.
Sulfurised alkyl phenols or the alkali metal salts and alkaline earth metal salts thereof may also be used as antioxidant additives.
Another class of antioxidant additives is that of copper compounds, for example thio- or dithio-phosphates of copper, copper salts and carboxylic acid salts, dithiocarbamates, sulphonates, phenates, copper acetylacetonates. Copper(I) and copper(II) salts, acid salts or succinic anhydride salts may also be used.
The lubricating composition according to the invention may contain all types of antioxidant additives known to the person skilled in the art.
In an advantageous manner, the lubricating composition comprises at least one ash-free antioxidant additive.
Also in an advantageous manner, the lubricating composition according to the invention comprises from 0.5 to 2% by weight in relation to the total weight of the composition, of at least one antioxidant additive.
The lubricating 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 metal parts by way of dissolving secondary products of oxidation and combustion.
The detergent additives used in the lubricating composition according to the invention are generally known to the person skilled in the art. The detergent additives may be anionic compounds comprising a lipophilic long 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 selected from among alkali metal salts or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, as well as the salts of phenates. The alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium or barium.
These metal salts generally contain the metal in a stoichiometric quantity or indeed in excess, hence in a quantity in excess of the stoichiometric quantity. These are then overbased detergent additives; the metal in excess providing the overbased character to the detergent additive is then generally in the form of an insoluble metal salt in the oil, for example a carbonate, a hydroxide, an oxalate, an acetate, a glutamate, preferably a carbonate.
In an advantageous manner, the lubricating composition of the invention may comprise from 2 to 4% by weight of detergent additive in relation to the total weight of the lubricating composition.
In an equally advantageous manner, the lubricating composition according to the invention may also comprise at least one pour point depressant additive.
By slowing down the formation of paraffin crystals, pour point depressant additives generally improve the cold temperature behaviour of the lubricating composition according to the invention.
By way of examples of pour point depressant additives mention may be made of alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, alkylated polystyrenes.
In an advantageous manner, the lubricating composition according to the invention may also comprise at least one dispersing agent.
The dispersing agent may be selected from Mannich bases, succinimides and derivatives thereof.
Also in an advantageous manner, the lubricating composition according to the invention may comprise from 0.2 to 10% by weight of dispersing agent in relation to the total weight of the lubricating composition.
The lubricating composition of the present invention may also comprise at least one additive that improves the viscosity index. By way of examples of additives that improve the viscosity index, mention may be made of polymeric esters, homopolymers or copolymers, either hydrogenated or non-hydrogenated, of styrene, butadiene and isoprene, polyacrylates, polymethacrylates (PMA) or even olefin copolymers, in particular ethylene/propylene copolymers.
The lubricating composition according to the invention may be presented in various forms. The lubricating composition according to the invention may in particular be an anhydrous composition.
In a preferred manner, the lubricating composition is not an emulsion.
The lubricating composition defined here above is used for preventing or reducing abnormal combustion of motor fuel in a motor vehicle engine.
The term ‘motor vehicle engine’ according to the invention is used to refer in particular to:

- petrol engines but also engines operating on gas and petrol (gas/petrol dual fuel engines) as well as engines operating on gas and diesel (gas/diesel dual fuel engines);
- engines for heavy goods (heavy duty) vehicles.

The term ‘abnormal combustion’ is used to refer to any phenomenon by which all or part of the fuel mixture is ignited in an uncontrolled manner within the combustion chamber of a motor vehicle engine.
The term ‘abnormal combustion according to the invention’ is used to refer more particularly to the following phenomena:

- pre-ignition, and in particular low speed pre-ignition (LSPI);
- knocking;
- super-knocking or mega-knocking which can follow a pre-ignition event.

The term ‘pre-ignition’ used according to the invention, includes the phenomenon of low frequency vibration that produces a sound effect akin to snoring (or “Rumble” as per the accepted terminology).
The term ‘motor fuel’ according to the invention, is used to refer more particularly to petrol or gas.
In one embodiment of the invention, the motor fuel is mixed with air.
In one particular embodiment of the invention, the lubricating composition is used for preventing and/or reducing abnormal combustion of motor fuel resulting from auto-ignition of the lubricating composition during the motor fuel compression cycle of the engine of the motor vehicle.
The object of the invention also 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 pre-ignition in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition, the fatty amine and the base oil described here above are equally applicable to this use.
Thus, the invention also 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 pre-ignition in a motor vehicle engine, the fatty amine being selected from among:

- fatty amines having the formula (I);

R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)

- a mixture of fatty polyalkylamines comprising one or more polyalkylamines having the formula (III) and/or (IV):

Preferably, the fatty amine is one having the formula (I);
R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)
All of the characteristic features and preferences relating to R₁, R₂, R₃, R₄and R₅described here above are equally applicable to this use.
The object of the invention also 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 low speed pre-ignition (LSPI) in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition, the fatty amine and the base oil described here above are equally applicable to this use.
Thus, the object of the invention also 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 low speed pre-ignition (LSPI) in an engine motor vehicle, the fatty amine being selected from among:

- fatty amines having the formula (I)

R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)

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

Preferably, the fatty amine is one having the formula (I);
R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)
All of the characteristic features and preferences relating to R₁, R₂, R₃, R₄and R₅described here above are equally applicable to this use.
The object of the invention also 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 knocking in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition, the fatty amine and the base oil described here above are equally applicable to this use.
The object of the invention also 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 abnormal combustion of the gas in a motor vehicle engine.
The term ‘motor vehicle engine’, is used to refer more particularly to engines for heavy goods (heavy duty) vehicles running on gas.
All of the characteristic features and preferences relating to the lubricating composition, the fatty amine and the base oil described here above are equally applicable to this use.
The object of the invention also relates to a method for preventing or reducing abnormal combustion of motor fuel in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
All of the characteristic features and preferences relating to the lubricating composition described here above are equally applicable to this method.
The object of the invention also relates to a method for preventing or reducing pre-ignition in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
All of the characteristic features and preferences relating to the lubricating composition described here above are equally applicable to this method.
The object of the invention also relates to a method for preventing or reducing low speed pre-ignition (LSPI) in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
All of the characteristic features and preferences relating to the lubricating composition described here above are equally applicable to this method.
The object of the invention also relates to a method for preventing or reducing the knocking in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
All of the characteristic features and preferences relating to the lubricating composition described here above are equally applicable to this method.
The object of the invention also relates to a method for preventing or reducing abnormal combustion of the gas in a motor vehicle engine, the said method comprising at least one contacting step for placing a mechanical part of an engine in contact with a lubricating composition as defined here above.
All of the characteristic features and preferences relating to the lubricating composition described here above are equally applicable to this method.
The object of the invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing abnormal combustion of motor fuel in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition and the fatty amine described here above are equally applicable to this use.
The object of the invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing pre-ignition in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition and the fatty amine described here above are equally applicable to this use.
The object of the invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing low speed pre-ignition b(LSPI) in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition and the fatty amine described here above are equally applicable to this use.
The object of the invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing the knocking in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition and the fatty amine described here above are equally applicable to this use.
The object of the invention also relates to the use of a fatty amine in a lubricating composition for preventing or reducing abnormal combustion of the gas in a motor vehicle engine.
All of the characteristic features and preferences relating to the lubricating composition and the fatty amine described here above are equally applicable to this use.

Claims

1-17. (canceled)

18. A method for preventing and/or reducing abnormal combustion of motor fuel in a motor vehicle engine comprising the step of lubricating the motor with a lubricating composition comprising at least one base oil and at least one fatty amine, wherein the fatty amine is selected from among:

fatty amines having the formula (I)

R₁—[(NR₂)—R₃]_n—NR₄R₅; (I)

wherein

R₁represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising at least 12 carbon atoms;

R₂, R₄or R₅independently represents, a hydrogen atom or a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched;

R₃represents a saturated or unsaturated hydrocarbon group, which is linear straight-chained or branched, comprising one or more carbon atom(s);

n represents an integer that is greater than or equal to 1;

a mixture of one or more polyalkylamines having the formulas (III) and/or (IV):

wherein

R, being either identical or different, represents an alkyl group, which is linear straight-chained or branched, comprising from 8 to 22 carbon atoms;

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 one another, represent 0, 1, 2 or 3;

the 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 derivatives thereof; or

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

19. The method according to claim 18, wherein:

R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 22 carbon atoms, and/or

R₂, R₄or R₅independently represents, a hydrogen atom; a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 22 carbon atoms; or a (R₆— O)_p—H group, wherein R₆is a saturated alkyl group, which is linear straight-chained or branched, comprising at least 2 carbon atoms, and p represents an integer that is greater than or equal to 1; and/or

R₃represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising between 2 and 6 carbon atoms.

20. The method according to claim 18, wherein:

n is equal to 1, 2 or 3;

R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 12 to 20 carbon atoms;

R₂independently represents a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 1 to 20 carbon atoms;

R₃represents a saturated and linear alkyl group, comprising between 2 and 6 carbon atoms;

R₄and R₅represent a hydrogen atom or a methyl group.

21. The method according to claim 18, wherein:

n is equal to 3;

R₂independently represents a hydrogen atom or a saturated alkyl group, which is linear straight-chained or branched, comprising from 16 to 18 carbon atoms;

R₃represents an ethyl or propyl group;

R₄and R₅represent a hydrogen atom.

22. The method according to claim 18, wherein:

n is equal to 1, 2 or 3;

R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 20 carbon atoms, advantageously from 16 to 20 carbon atoms;

R₂, R₄and R₅independently represents, a hydrogen atom or a (R₆— O)_p—H group, wherein R₆is a saturated linear alkyl group, comprising between 2 and 6 carbon atoms, and with p representing an integer comprised between 1 and 6;

R₃represents a saturated and linear alkyl group, comprising between 2 and 6 carbon atoms.

23. The method according to claim 18, wherein:

n is equal to 3;

R₁represents a saturated or unsaturated alkyl group, which is linear straight-chained or branched, comprising from 14 to 20 carbon atoms;

R₂, R₄and R₅independently represents, a hydrogen atom or a (R₆— O)_p— H group, wherein R₆is a saturated linear alkyl group, comprising between 2 and 4 carbon atoms, and with p representing an integer comprised between 1 and 4;

R₃represents an ethyl or propyl group.

24. The method according to claim 18, wherein the mixture of polyalkylamines having the formulas (III) and/or (IV) comprises at least 5% by weight of compounds having a pure linear structure.

25. The method according to claim 18, wherein the mixture of polyalkylamines having the formulas (III) and/or (IV) comprises at least 4% by weight, of branched compounds such that at least n or z is greater than or equal to 1.

26. The method according to claim 18, wherein the mixture of polyalkylamines having the formulas (III) and/or (IV) comprises at least polyalkylamines having the 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.

27. The method according to claim 18, wherein the mixture of polyalkylamines having the formulas (III) and/or (IV) comprises at least polyalkylamines having the formulas (III) and/or (IV) for which n, o, p, or z independently represent 0, 1 or 2.

28. The method according to claim 18, wherein the mixture of polyalkylamines having the formulas (III) and/or (IV) comprises at least polyalkylamines having the formulas (III) and/or (IV) and derivatives thereof for which n, o, p and z independently represent 0, 1 or 2.

29. The method according to claim 18, wherein the mixture of fatty amines having the formulas (I), (III) and/or (IV) represents from 0.1 to 15% by weight in relation to the total weight of the lubricating composition.

30. The method according to claim 18, wherein the fatty amine represents from 0.1 to 5% by weight in relation to the total weight of the lubricating composition.

31. The method according to claim 18, wherein the motor fuel is mixed with air.

32. A method for preventing and/or reducing pre-ignition in a motor vehicle engine comprising the step of lubricating the engine with a lubricating composition comprising at least one base oil and at least one fatty amine.

33. A method for preventing and/or reducing low speed pre-ignition (LSPI) in a motor vehicle engine comprising the step of lubricating the engine with a lubricating composition comprising at least one base oil and at least one fatty amine.

34. A method for preventing and/or reducing knocking in a motor vehicle engine comprising the step of lubricating the engine with a lubricating composition comprising at least one base oil and at least one fatty amine.

35. The method of claim 18, wherein R₁represents at least one heteroatom selected from nitrogen, sulfur or oxygen.

36. The method of claim 35, wherein R₂, R₄or R₅independently comprises at least one heteroatom selected from nitrogen, sulfur or oxygen.

37. The method of claim 36, wherein R₃comprises at least one heteroatom selected from nitrogen, sulfur or oxygen.