EP3523407B1 - Lubricanting composition for a marine engine or a stationary engine - Google Patents

Description

The present invention is applicable to the field of lubricating compositions, and more particularly to the field of lubricating compositions for a marine engine, in particular for a four-stroke or two-stroke marine engine, preferably for a four-stroke marine engine, or for a stationary engine. More particularly, the present invention relates to lubricating compositions the use of which promotes fuel savings (Fuel Eco or FE or even Gas Eco or GE) and having good engine cleanliness properties, in particular crankcase cleanliness. The present invention also relates to a process for reducing the fuel consumption, in particular fuel oil, of a ship or of a power plant using this lubricating composition.

In the automotive sector, due to environmental concerns, more and more efforts are being made to reduce polluting emissions and to save fuel. The nature of motor lubricants for automobiles has an influence on these two phenomena, and motor lubricants for automobiles known as “fuel-eco” (in English terminology) have emerged. It is mainly the quality of the lubricating bases, alone or in combination with polymers which improve the viscosity index and / or friction modifying additives, which gives the lubricant its “fuel-eco” properties. The fuel savings generated by “fuel-eco” engine lubricants are essentially achieved during cold starts, when the engine is not yet in stabilized mode, and not at high temperature in stabilized mode. In general, the consumption savings in the NEDC cycle (New European Driving Cycle or New European Driving Cycle) according to European directive 70/220 / EEC are cold (urban cycle) of 5%, hot (extra cycle). -urban) of 1.5%, for average gains of 2.5%.
However, in the field of marine lubricants, marine engines operate at a stabilized speed, there are few cold starts. "Fuel-eco" solutions adapted to automobile engines are therefore not adapted to marine engines. In particular, the savings in consumption obtained in the automobile sector cannot be obtained in the marine sector.
In addition, the “fuel-eco” issue is also highlighted in stationary power plant motors.

Furthermore, the formulation of a “fuel-eco” and / or “gas-eco” lubricant must not be done to the detriment of the other performances of the lubricant. In particular, the resistance to wear, demulsion, neutralization capacity, and the cleanliness of the engine (piston and / or crankcase) must not be impaired.

We know in particular of WO 2007/121039 a lubricating composition comprising a copolymer comprising an olefin block and a vinyl aromatic block and in particular its use for reducing engine fouling. We also know of WO 2013/045648 a composition comprising at least one olefin copolymer, at least one hydrogenated styrene-isoprene copolymer, at least one glycerol ester and its use to improve Fuel Eco and limit engine fouling. We finally know of WO 2014/135596 a lubricating composition comprising at least one alkoxylated fatty amine and at least one copolymer of styrene and hydrogenated isoprene, and its use to improve Fuel Eco and limit engine fouling.
WO2004087849 discloses a lubricating composition comprising a base oil, a copolymer (A) comprising ethylene units and a copolymer (B) comprising a vinyl aromatic block and a hydrogenated diene block.

There is therefore an advantage in having a lubricating composition for a marine engine or for a stationary engine which allows satisfactory reductions in fuel consumption (fuel oil and / or gas), in particular fuel oil, while maintaining the other performances of the engine. lubricating composition, in particular the cleanliness of the engine, more specifically the cleanliness of the crankcase.
There is also an advantage in having a lubricating composition for a marine engine or for a stationary engine having good thermal resistance under severe conditions of use, and more particularly in the presence of fuel (fuel oil and / or gas), in particular of fuel. Indeed, during the combustion of fuel oil or gas within the engine, residues and unburnt combustion can pollute the lubricating composition and thus alter its thermal resistance and its detergency properties.

An objective of the present invention is therefore to provide a lubricating composition which overcomes all or part of the aforementioned drawbacks. In particular, an objective of the present invention is to provide a lubricating composition for a marine engine or for a stationary engine allowing a saving of fuel (fuel oil and / or gas), in particular a saving of Fuel Eco (FE), while maintaining engine cleanliness. .

Another objective of the present invention is to provide a lubrication process allowing savings in fuel (fuel oil and / or gas), in particular fuel oil, while maintaining good engine cleanliness.
Still other objectives will become apparent on reading the description of the invention which follows.

• au moins une huile de base ;
• au moins un détergent, choisi parmi les détergents sels de métaux alcalins ou alcalino-terreux de carboxylate, sulfonate, salicylate, ou phénate en une teneur allant de 10% à 30% en masse par rapport à la masse totale de ladite composition lubrifiante ;
• 0,01 à 5% en masse par rapport à la masse totale de ladite composition lubrifiante d'au moins un copolymère oléfine ;
• 0,01 à 8% en masse par rapport à la masse totale de ladite composition lubrifiante d'au moins un copolymère styrène/butadiène hydrogéné et linéaire.

The subject of the invention is thus a lubricating composition comprising:

• at least one base oil;
• at least one detergent, chosen from detergents which are alkali metal or alkaline earth metal salts of a carboxylate, sulphonate, salicylate or phenate in a content ranging from 10% to 30% by mass relative to the total mass of said lubricating composition;
• 0.01 to 5% by mass relative to the total mass of said lubricating composition of at least one olefin copolymer;
• 0.01 to 8% by mass relative to the total mass of said lubricating composition of at least one hydrogenated linear styrene / butadiene copolymer.

Surprisingly, the Applicant has observed that it was possible to formulate lubricating compositions for marine engines or for stationary engines making it possible to significantly reduce the consumption of fuels (fuel oil and / or gas), in particular fuel (Fuel Eco), while by maintaining or even improving engine cleanliness, in particular crankcase cleanliness, compared to conventional lubricating compositions for marine engines or for stationary engines. This is made possible by a lubricating composition comprising at least one base oil, at least one detergent, at least one olefin copolymer and at least one hydrogenated and linear styrene-butadiene copolymer.

Thus, the present invention makes it possible to formulate lubricating compositions for a 4-stroke or 2-stroke, preferably 4-stroke, marine engine, or for a stationary engine, making it possible to combine both engine cleanliness and fuel savings (fuel and fuel). / or gas), in particular fuel (Fuel Eco).

Advantageously, the lubricating compositions according to the invention exhibit improved thermal resistance under severe conditions, and more particularly in the presence of fuel, in particular fuel oil.

Advantageously, the lubricating compositions according to the invention exhibit improved storage stability as well as a viscosity which does not vary or very little over time.

In one embodiment of the invention, the linear hydrogenated styrene / butadiene copolymer can be chosen from styrene / hydrogenated butadiene block copolymers or statistical styrene / hydrogenated butadiene copolymers, or mixtures thereof.

Advantageously, the linear hydrogenated styrene / butadiene copolymer has a content of hydrogenated butadiene units ranging from 50% to 98% by mass, preferably from 60% to 98%, more preferably from 60% to 90%, relative to to the mass of linear hydrogenated styrene / butadiene copolymer.

Advantageously, the linear hydrogenated styrene / butadiene copolymer has a content of hydrogenated butadiene units, ranging from 50% to 98% by moles, preferably from 60% to 98%, more preferably from 70 to 97%, more preferably from 70% to 95%, based on the number of moles of the linear hydrogenated styrene / butadiene copolymer.

Advantageously, the linear hydrogenated styrene / butadiene copolymer has a content of styrene units ranging from 2% to 50%, preferably from 2% to 40%, more preferably from 10% to 40% by mass relative to the mass of linear hydrogenated styrene / butadiene copolymer.

Advantageously, the hydrogenated linear styrene / butadiene copolymer has a content of styrene units ranging from 2% to 50%, preferably from 2% to 40%, more preferably from 5% to 30% by mole relative to the number of moles of the linear hydrogenated styrene / butadiene copolymer.

In one embodiment of the invention, the hydrogenated linear styrene / butadiene copolymer according to the invention has a weight average molecular mass Mw ranging from 80,000 to 500,000 daltons, preferably from 80,000 to 250,000 daltons, plus preferably from 80,000 to 200,000 daltons, even more preferably from 80,000 to 150,000 daltons.

In one embodiment of the invention, the linear hydrogenated styrene / butadiene copolymer according to the invention has a polydispersity index ranging from 0.8 to 1.4, preferably from 0.8 to 1.2.

In one embodiment of the invention, the hydrogenated butadiene units are formed from 5 to 40% by mass of addition 1-4 butadiene, preferably from 20 to 40% relative to the mass of butadiene units in the copolymer linear hydrogenated styrene / butadiene and from 20 to 60% by mass of addition 1-2 butadiene, preferably from 30 to 60% relative to the mass of butadiene units in the styrene / hydrogenated and linear butadiene copolymer.

In another embodiment of the invention, the hydrogenated butadiene units are formed from 10 to 60 mole% of addition 1-4 butadiene, preferably 20 to 50% based on the number of moles of butadiene units in the linear hydrogenated styrene / butadiene copolymer and from 30 to 80% by mole of addition 1-2 butadiene, preferably from 40 to 60% relative to the number of moles of butadiene units in the styrene / hydrogenated and linear butadiene copolymer .

As examples of a linear hydrogenated styrene / butadiene copolymer according to the invention, mention may be made of the linear hydrogenated styrene / butadiene polymers sold by the company Lubrizol.

In one embodiment of the invention, the content by weight of linear hydrogenated styrene / butadiene copolymer in the lubricating composition according to the invention is from 0.01% to 8% by mass, relative to the total mass of the lubricating composition, preferably from 0.1% to 5%, more preferably from 0.1% to 2%, advantageously from 0.1 to 1%. This quantity is understood as a quantity of active polymer material. In fact, the linear hydrogenated styrene / butadiene copolymer used in the context of the present invention can be in the form of a dispersion in a mineral or synthetic oil, and more particularly in a group I oil according to the API classification.

Preferably, the olefin copolymer is an ethylene-propylene copolymer.
These olefin copolymers are conventionally copolymers based on ethylene units and on propylene units, or optionally copolymers based on units. ethylene, propylene units and diene units (EPDM). Preferably, the olefin copolymer according to the invention is an ethylene / propylene copolymer.
The olefin copolymer according to the invention is in linear or star form, preferably in linear form. The olefin copolymer according to the invention is in the form of blocks or in random form.
The olefin copolymer according to the invention advantageously has a content of ethylene units, ranging from 30% to 80% by mass, relative to the mass of olefin copolymer, preferably from 30% to 70%, more preferably from 40%. at 70%.
The olefin copolymer according to the invention also advantageously has a content of ethylene units, ranging from 40% to 90% by mole, relative to the number of moles of olefin copolymer, preferably from 40% to 80%, more preferably from 50% to 80%.

The olefin copolymer according to the invention advantageously has a content of propylene units, ranging from 20% to 70% by mass, relative to the mass of olefin copolymer, preferably from 20% to 60%, more preferably from 20%. at 50%.
The olefin copolymer according to the invention also advantageously has a content of propylene units, ranging from 10% to 60% by mole, relative to the number of moles of olefin copolymer, preferably from 20% to 60%, more preferably from 20% to 50%.

The olefin copolymer according to the invention advantageously has a weight-average molecular mass Mw of between 40,000 and 220,000 daltons, preferably between 60,000 and 220,000 daltons, more preferably between 100,000 and 220,000 daltons, even more preferably between 140,000 and 210,000 daltons.

The olefin copolymer according to the invention advantageously has a polydispersity index of between 1.5 and 5, preferably between 2 and 5, more preferably between 2 and 4, even more preferably between 2 and 3.5.

The amount of olefin copolymer in the lubricating composition according to the invention is from 0.01% to 5% by mass, relative to the total mass of the lubricating composition, preferably from 0.01% to 2%, more preferably from 0.01% to 1%, even more preferably from 0.1% to 1%. This quantity is understood as a quantity of dry polymer material. Indeed, the olefin copolymer used in the context of the present invention is sometimes found in dilution in a mineral or synthetic oil (most often a group 1 oil according to the API classification).

In one embodiment, the lubricating composition according to the invention can comprise at least one detergent.

The detergents used in the lubricating compositions according to the present invention are well known to those skilled in the art.
Detergents commonly used in the formulation of lubricating compositions are typically anionic compounds having a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation is typically a metallic cation of an alkali or alkaline earth metal.
The detergents according to the invention are chosen from alkali metal or alkaline earth metal salts of carboxylic acids, sulphonates, salicylates and phenates taken alone or as a mixture. Detergents are named after the nature of the hydrophobic, carboxylate, sulfonate, salicylate or phenate chain.
The alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium or barium, more preferably calcium.
The detergents used will not be overbased (or neutral) or overbased. We speak of non-overbased or "neutral" detergents when the metal salts contain the metal in approximately stoichiometric quantity. We speak of overbased detergents, when the metal is in excess (in an amount greater than the stoichiometric amount). The excess metal imparting the overbased character to the detergent is in the form of oil-insoluble metal salts. The overbased detergents are thus in the form of micelles composed of insoluble metal salts maintained in suspension in the lubricating composition by the detergents in the form of oil-soluble metal salts. These micelles can contain one or more types of insoluble metal salts, stabilized by one or more types of detergents. The overbased detergents will be said to be of mixed type if the micelles include several types of detergents, which are different from one another by the nature of their hydrophobic chain.
The preferred detergents are the carboxylates, the sulphonates and / or the phenates, taken alone or as a mixture, in particular the carboxylates, the sulphonates and / or the calcium phenates.
The amount of detergents in the lubricating composition according to the invention is from 1% to 30% by mass, relative to the total mass of the lubricating composition, preferably from 1% to 25%, more preferably from 1% to 20% , even more preferably from 3% to 20%.

Preferably, the amount of detergents in the lubricating composition according to the invention is from 10% to 30%, preferably from 10% to 25%, and more preferably from 10% to 20%, by mass relative to the total mass of said lubricating composition.

The BN (Base Number measured according to ASTM D-2896) of the lubricating compositions according to the present invention is totally or partly provided by neutral or overbased detergents based on alkali or alkaline earth metals.
The BN value of the lubricating compositions according to the present invention, measured according to ASTM D-2896 can vary from 3 to 140 mg of KOH / g, preferably from 3 to 80 mg of KOH / g, more preferably from 4 to 60 mg of KOH / g. The BN value will be chosen as a function of the conditions of use of the lubricating compositions and in particular according to the sulfur content of the fuel used.
Thus, for heavy fuel oils with a sulfur content ranging from 0.1% to 3.5% by weight, the BN value of the composition will be between 20 and 80 mg of KOH / g, more preferably between 20 and 65 mg of KOH / g. These compositions are preferably used in 4T marine engines or in stationary engines.
Thus also for heavy fuel oils with a sulfur content ranging from 0.1% to 3.5% by weight, the BN value of the composition will be between 20 and 140 mg of KOH / g, more preferably between 20 and 100 mg. of KOH / g. These compositions are preferably used in 2-stroke marine engines, in particular for cylinder oils.
For gas oils with a sulfur content ranging from 0.05% to 2% by weight, the BN value of the composition is between 5 and 30 mg of KOH / g, more preferably between 10 and 20 mg of KOH / g. These compositions are preferably used in 4T marine engines or in stationary engines.
For gases, the BN value of the composition is less than 10 mg of KOH / g, more preferably between 2 and 8 mg of KOH / g. These compositions are preferably used in 4T marine engines or in stationary engines.

In the remainder of the present invention, essential additives will be referred to as the additives described above, that is to say a) at least one olefin copolymer, b) at least one copolymer of styrene and of hydrogenated and linear butadiene, c ) at least one detergent as defined above.

In general, the base oils used for the formulation of lubricating compositions according to the invention can be chosen from oils of mineral, synthetic or vegetable origin as well as their mixtures.

The mineral or synthetic oils generally used in the marine engine oil application belong to one of the classes defined in the API classification as summarized in the table below. Saturated content Sulfur content Viscosity index (VI) Group I Mineral oils <90% > 0.03% 80 ≤ VI <120 Group II Hydrocracked oils > 90% ≤ 0.03% 80 ≤ VI <120 Group III Hydro-isomerized oils > 90% ≤ 0.03% ≥ 120 Group IV Poly-alpha-olefins (PAO) Group V Other bases not included in groups I to IV bases

Group I mineral oils can be obtained by distillation of selected naphthenic or paraffinic crudes followed by purification of these distillates by processes such as solvent extraction, solvent or catalytic dewaxing, hydrotreatment or hydrogenation. Group I mineral bases are, for example, bases called Neutral Solvant (such as 150NS, 330NS, 500NS or 600NS) or Brightstock.
The oils of Groups II and III are obtained by more stringent purification processes, for example a combination of hydrotreatment, hydrocracking, hydrogenation and catalytic dewaxing.
Examples of Group IV and V synthetic bases include poly-alpha olefin, polybutenes, polyisobutenes, alkylbenzenes.
These base oils can be used alone or as a mixture. Mineral oil can be combined with synthetic oil.

In a preferred embodiment of the invention, the lubricating base oil is chosen from the base oils of group I or of group II, taken alone or as a mixture.

In one embodiment of the invention, the lubricating composition according to the invention can be characterized by a viscosimetric grade SAE-20, SAE-30, SAE-40, SAE-50 or SAE-60 according to the SAEJ300 classification, preferably SAE-30 or SAE-40, advantageously SAE-30.
Grade 20 oils have a kinematic viscosity at 100 ° C between 5.6 and 9.3 cSt. Grade 30 oils have a kinematic viscosity at 100 ° C between 9.3 and 12.5 cSt. Grade 40 oils have a kinematic viscosity at 100 ° C between 12.5 and 16.3 cSt. Grade 50 oils have a kinematic viscosity at 100 ° C between 16.3 and 21.9 cSt. Grade 60 oils have a kinematic viscosity at 100 ° C between 21.9 and 26.1 cSt.
Kinematic viscosity is measured according to ASTM D7279 at 100 ° C.

In a preferred embodiment, the lubricating composition according to the invention has a kinematic viscosity measured according to standard ASTM D7279 at 100 ° C of between 5.6 and 26.1 cSt, preferably between 9.3 and 21.9 cSt , more preferably between 9.3 and 16.3 cSt.

In one embodiment of the invention, the content by weight of base oil in the lubricating composition according to the invention is from 40% to 95%, preferably from 50% to 95%, more preferably from 60% to 95%, advantageously from 60 to 85% relative to the total weight of the lubricating composition.

In one embodiment, the lubricating composition is not in the form of an emulsion.

In addition to the essential additives as described above, the composition according to the invention can comprise at least one optional additive, in particular chosen from those commonly used by a person skilled in the art. For example, the optional additive can be selected from dispersant additives, antiwear additives, antioxidants, friction modifiers, pour point improvers, defoamers, thickeners, fatty amines and theirs. mixtures. These are well known to those skilled in the art.

In one embodiment, the lubricating composition according to the invention can also comprise a dispersant.
Dispersants are well known additives used in the formulation of lubricating compositions, in particular for application in the marine field. Their role the first is to maintain in suspension the particles initially present or appearing in the lubricating composition during its use in the engine. They prevent their agglomeration by playing on steric hindrance. They can also exhibit a synergistic effect on neutralization.
Dispersants used as lubricant additives typically contain a polar group, associated with a relatively long hydrocarbon chain, generally containing from 50 to 400 carbon atoms. The polar group typically contains at least one element nitrogen, oxygen or phosphorus.

In one embodiment of the invention, the dispersant can be chosen from derivatives of succinic acid. Among the succinic acid derivatives, within the meaning of the invention, is meant the esters of succinic acid or the amide esters of succinic acid. Preferably, the dispersant is chosen from compounds comprising at least one succinimide group.

These compounds can then be treated with various compounds including sulfur, oxygen, formaldehyde, carboxylic acids and compounds containing boron or zinc to produce for example borated succinimides or succinimides blocked with zinc.

In a preferred embodiment of the invention, the dispersant is chosen from borated compounds comprising at least one succinimide group.
In a preferred embodiment of the invention, the dispersant can be chosen from borated compounds comprising at least one substituted succinimide group or borated compounds comprising at least two substituted succinimide groups, the succinimide groups possibly being linked at their summit. carrying a nitrogen atom via a polyamine group.
For the purposes of the present invention, the term “substituted succinimide group” means a succinimide group of which at least one of the vertices is substituted by a hydrocarbon group comprising from 8 to 400 carbon atoms.

Advantageously, the dispersant is chosen from borated compounds comprising at least one succinimide group substituted with a polyisobutene group.

Advantageously, the dispersant is chosen from borate compounds comprising at least two succinimide groups each substituted by a polyisobutene group.

• Une masse moléculaire en nombre du polyisobutène supérieure à 2000 Daltons, de préférence allant de 2000 à 5000 Daltons, avantageusement de 2000 à 3000 Daltons,
• Une teneur massique en élément bore supérieure ou égale à 0,35% par rapport à la masse totale du dispersant.

More advantageously, the dispersant is chosen from borated compounds comprising at least two succinimide groups each substituted by a polyisobutene group and characterized by:

• A number molecular mass of the polyisobutene greater than 2000 Daltons, preferably ranging from 2000 to 5000 Daltons, advantageously from 2000 to 3000 Daltons,
• A boron element mass content greater than or equal to 0.35% relative to the total mass of the dispersant.

Mannich bases, obtained by polycondensation of phenols substituted with alkyl groups, formaldehyde and primary or secondary amines, can also be used as a dispersant in the lubricating composition according to the invention.

In one embodiment of the invention, the content by weight of dispersant is at least 0.1%, preferably from 0.1% to 10%, advantageously from 1% to 6% relative to the total weight of the mixture. lubricating composition.

Anti-wear additives protect rubbing surfaces by forming a protective film adsorbed on these surfaces. There is a wide variety of antiwear additives. Mention may thus be made of phospho-sulfur additives, such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates (or ZnDTP). The alkyl groups of these zinc dialkyldithiophosphates preferably contain from 1 to 18 carbon atoms. Amine phosphates and polysulphides, in particular sulfur-containing olefins, are also commonly used anti-wear additives. Nitrogenous and sulfur-containing anti-wear additives are also encountered, such as, for example, metal dithiocarbamates, in particular molybdenum dithiocarbamates. The preferred antiwear additive is ZnDTP.

The content by weight of anti-wear additive in the lubricant according to the invention is from 0.1% to 5%, preferably from 0.2% to 4%, more preferably from 0.2% to 2% relative to to the total weight of the lubricating composition.

For example, for pour point improvers additives, polymethacrylates (PMA) can be used.

The lubricating composition according to the invention can also comprise friction modifiers. Friction modifiers help reduce friction between engine parts as much as possible. These additives help prevent engine damage while increasing fuel economy. They can be chosen from organic molecules having a polar function at one end: carboxylic acid and derivatives, glycerol ester, imides, fatty amides, fatty amines and derivatives, phosphoric or phosphonic acid derivatives (phosphite or amine phosphate ). They act by chemical reaction on the metal surface or by absorption at the metal surface (hydrogen bonding).
Another type of friction modifier can be selected from organometallic compounds: molybdenum disthiophosphate, molybdenum dithiocarbamate, copper oleate, copper salicylate.
Finally, the friction modifier can be a solid compound: the most common being molybdenum disulfide MoS2, Boron nitride, polytetrafluoroethylene (PTFE). The content by weight of the friction modifier in the lubricant according to the invention is from 0.1% to 5%, preferably from 0.2% to 4%, more preferably from 0.2% to 2% relative to the weight total lubricant composition.

The anti-foam additives can be chosen from polar polymers such as polymethylsiloxanes or polyacrylates.
These additives are generally present at a content by weight of 0.01 to 3% relative to the total weight of the lubricating composition.

• R₁ représente un groupement hydrocarboné saturé ou insaturé, linéaire ou ramifié, comprenant au moins 12 atomes de carbone, et optionnellement au moins un hétéroatome choisi parmi l'azote, le soufre ou l'oxygène,
• R₂, R₄ ou R₅ représente indépendamment, un atome d'hydrogène ou un groupement hydrocarboné saturé ou insaturé, linéaire ou ramifié, et comprenant optionnellement au moins un hétéroatome choisi parmi l'azote, le soufre ou l'oxygène,
• R₃ représente un groupement hydrocarboné saturé ou insaturé, linéaire ou ramifié, comprenant un ou plusieurs atome(s) de carbone, et comprenant optionnellement au moins un hétéroatome choisi parmi l'azote, le soufre ou l'oxygène, de préférence l'oxygène,
• n est supérieur ou égal à 0, de préférence n est supérieur ou égal à 1, plus préférentiellement est un entier compris entre 1 et 10, encore plus préférentiellement entre 1 et 6, avantageusement est choisi parmi 1, 2 ou 3.

Additives of the lubricating composition can also be chosen from fatty amines and in particular from at least one fatty amine of formula (I):

R ₁ - [(NR ₂ ) -R ₃ ] _n -NR ₄ R ₅ ,

in which,

• R ₁ represents a saturated or unsaturated, linear or branched hydrocarbon group 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, linear or branched hydrocarbon group, and optionally comprising at least one heteroatom chosen from nitrogen, sulfur or oxygen,
• R ₃ represents a saturated or unsaturated, linear or branched hydrocarbon group comprising one or more carbon atom (s), and optionally comprising at least one heteroatom chosen from nitrogen, sulfur or oxygen, preferably oxygen ,
• n is greater than or equal to 0, preferably n is greater than or equal to 1, more preferably is an integer between 1 and 10, even more preferably between 1 and 6, advantageously is chosen from 1, 2 or 3.

dans lesquelles

• R, identique ou différent, représente un groupe alkyle, linéaire ou ramifié, comprenant de 8 à 22 atomes de carbone,
• n et z, indépendamment l'un de l'autre, représentent 0, 1, 2 ou 3, et
• quand z est supérieur à 0, o et p, indépendamment l'un de l'autre, représentent 0, 1 ,2 ou 3,

ledit mélange comprenant au moins 3% en poids de composés ramifiés tels que au moins un de n ou z est supérieur ou égal à 1, ou de leurs dérivés.Preferably, the fatty amine can be chosen from mixtures of fatty polyalkylamines comprising one or more polyalkylamines of formulas (II) and / or (III):

in which

• R, identical or different, represents an alkyl group, linear or branched, 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.

In one embodiment, the percentage by weight of fatty amine is between 1 and 15% relative to the total weight of the lubricating composition, preferably between 1 and 10%.

• la quantité de copolymère styrène/butadiène hydrogéné et linéaire s'entend en quantité de matière active de polymère ;
• la quantité de copolymère oléfine s'entend en quantité de matière active de polymère.

As mentioned above:

• the amount of linear hydrogenated styrene / butadiene copolymer is understood to mean the amount of active polymer material;
• the amount of olefin copolymer is understood as the amount of active polymer material.

Advantageously, the lubricating composition according to the invention allows a fuel gain (Fuel Eco and / or Gas Eco) greater than 0.7% to 75% load, preferably at least 0.8% to 75% load, more preferably at least 0.9% to 75% load.

Advantageously, the lubricating composition according to the invention also allows a saving in fuel (Fuel Eco and / or Gas Eco) of at least 0.9% to 100% of load, preferably of at least 1% to 100 % dump.

The lubricating composition according to the invention can be advantageously used in 4-stroke or 2-stroke marine engines, preferably 4-stroke, or stationary engines.
In a preferred embodiment, the lubricating composition is used in fast or semi-fast 4-stroke engines, which operate respectively with distillates and bunker or heavy fuel oils and also with gas. They can also be used as power generation units on board large ships or implemented in stationary engines of diesel-electric power stations.

In particular, the lubricating composition is suitable for 4-stroke engines as a quill piston engine oil also called TPEO oil.

In particular, the lubricating composition is suitable for 2-stroke engines as system oil or cylinder oil.

In particular, the lubricating composition is suitable for stationary engines as a piston oil for a quill piston engine also called TPEO oil.

Thus, a subject of the invention is also an oil for a cylinder piston engine, also called TPEO oil (trunk piston engine oil in English) comprising a lubricating composition as defined above.
The term “piston oil for a quill piston engine, also called TPEO oil according to the invention, is understood to mean any lubricating composition intended for the lubrication of 4-stroke marine engines or stationary engines, in particular of the crankcase and of the cylinders.

The invention also relates to a cylinder oil comprising a lubricating composition as defined above.
By cylinder oil according to the invention is meant any lubricating composition intended for lubricating the cyclinders of 2-stroke marine engines.

The invention also relates to a system oil comprising a lubricating composition as defined above.
The term “system oil according to the invention” is understood to mean any lubricating composition intended for lubricating the lower part of 2-stroke marine engines, in particular the crank pins, the camshaft and the crankshaft bearings. System oil also protects the crankcase and cools the piston heads.
In addition, it also serves as a hydraulic fluid.

A subject of the invention is also the use of a lubricating composition as defined above for the lubrication of 4-stroke or 2-stroke marine engines or of stationary engines. In a preferred embodiment, the invention relates to the use of a lubricating composition as defined above for the lubrication of 4-stroke marine engines or of stationary engines.
All of the characteristics and preferences presented for the lubricating composition apply to the above use.

The invention also relates to the use of a lubricating composition as defined above for reducing the consumption of fuel (fuel oil and / or gas), in particular fuel oil, in an engine, in particular 4-stroke or 2-stroke marine engines. time or stationary engines, while improving engine cleanliness, preferably crankcase cleanliness.
In a preferred embodiment, the invention relates to the use of a lubricating composition as defined above for reducing fuel consumption, in particular fuel from 4-stroke marine engines or stationary engines, while improving the fuel efficiency. engine cleanliness, preferably crankcase cleanliness.
The reduction in fuel consumption, in particular fuel oil, is evaluated in particular by tests on an engine bench or by evaluation of the traction coefficient on a test machine, in particular on an MTM machine (Mini Traction Machine).
Engine cleanliness is assessed in particular by continuous ECBT methods.
All of the characteristics and preferences presented for the lubricating composition apply to the above use.

The compounds as defined above contained in the lubricating composition according to the invention, and more particularly the olefin copolymer and the styrene / hydrogenated butadiene copolymer can be incorporated into the lubricating composition as separate additives, in particular by separate addition of these in base oils. However, they can also be integrated into a concentrate of additives for a marine lubricating composition or for a stationary engine lubricating composition.

• au moins un détergent,
• au moins copolymère oléfine,
• au moins un copolymère styrène/butadiène hydrogéné et linéaire.

Thus, there is also disclosed a composition of the additive concentrate type comprising:

• at least one detergent,
• at least olefin copolymer,
• at least one hydrogenated linear styrene / butadiene copolymer.

All the characteristics and preferences presented for the detergent, the olefin copolymer and the hydrogenated and linear styrene / butadiene copolymer also apply to the above composition.

The composition of the additive concentrate type can be added to at least one base oil to obtain a lubricating composition according to the invention.

A method of reducing fuel consumption, in particular fuel oil, and improving engine cleanliness, in particular crankcase cleanliness, is also disclosed, comprising contacting the lubricating composition as defined above or obtained from concentrate as defined above, with a marine engine or a stationary engine.

All the characteristics and preferences presented for the lubricating composition or for the composition of the additive concentrate type also apply to the lubrication process according to the invention.

The various subjects of the present invention and their applications will be better understood on reading the examples which follow. These examples are given as an indication, without a limiting nature.

Examples

The compositions C ₁ , C ₂ , L ₁ , L ₂ and L ₃ are obtained from the following components:
The olefin copolymer used in the examples comprises 67% by moles of ethylene units and 33% by moles of propylene units, 58% by mass of ethylene units and 42% by mass of propylene units, and has an average molecular mass by mass between 170,000 Da and 200,000 Da. It exhibits a viscosity at 100 ° C of 4500 cSt when diluted to a content of 7% by mass in a group 1 oil.
The commercial olefin copolymer is diluted to 5% by mass in a group 1 base oil for compositions L ₁ and L ₃ .
The commercial olefin copolymer is diluted to 2.3% by mass in a group 1 base oil for composition L ₂ .

The linear hydrogenated styrene-butadiene copolymer used in the examples comprises 82% by moles of hydrogenated butadiene units (including 32% by moles of 1-4 addition butadiene units and 50% by moles of addition butadiene units 1 -2) and 18% by moles of styrene units, 72% by mass of hydrogenated butadiene units (including 28% by mass of addition butadiene units 1-4 and 44% by mass of addition butadiene units 1-2) and 29% by weight of styrene units.
It has a mass average molecular mass of between 120,000 Da and 150,000 Da and has a polydispersity index of between 1 and 1.1.

• un paquet détergent 1 comprenant des détergents à base de carboxylates de calcium, de phénates de calcium, un additif anti-usure, le dithiophosphate de zinc (ZnDTP), un anti-mousse et un modificateur de frottement, le paquet étant dilué entre 40 et 60% en masse, dans une huile de base de groupe 1,
• un paquet détergent 2 comprenant des détergents à base de carboxylates de calcium, de phénates de calcium, un additif anti-usure, le dithiophosphate de zinc (ZnDTP), un anti-mousse, le paquet étant dilué entre 40 et 60% en masse, dans une huile de base de groupe 1,
• huiles de base de groupe 2, en particulier bases appelées 100R et 220R, respectivement de viscosité de 4,1 cSt et de 6,4 cSt à 100°C, et de 20,2 cSt et de 41,5 cSt à 40°C
• huiles de base de groupe 1, en particulier bases appelées Neutral Solvant 100NS et 150NS, respectivement de viscosité de 4,1 cSt et 5,3 cSt à 100°C, et de 20,2 cSt et 31,0 cSt à 40°C .

The commercial linear hydrogenated styrene-butadiene copolymer is diluted to 8% by mass in a group 1 base oil for compositions L ₁ , L ₂ and L ₃ .

• a detergent package 1 comprising detergents based on calcium carboxylates, calcium phenates, an anti-wear additive, zinc dithiophosphate (ZnDTP), an anti-foam and a friction modifier, the package being diluted between 40 and 60% by mass, in a group 1 base oil,
• a detergent package 2 comprising detergents based on calcium carboxylates, calcium phenates, an anti-wear additive, zinc dithiophosphate (ZnDTP), an anti-foam, the package being diluted between 40 and 60% by weight, in a group 1 base oil,
• Group 2 base oils, in particular bases called 100R and 220R, respectively with a viscosity of 4.1 cSt and 6.4 cSt at 100 ° C, and of 20.2 cSt and 41.5 cSt at 40 ° C
• base oils of group 1, in particular bases called Neutral Solvant 100NS and 150NS, respectively with a viscosity of 4.1 cSt and 5.3 cSt at 100 ° C, and of 20.2 cSt and 31.0 cSt at 40 ° C .

• un copolymère styrène/isoprène hydrogéné (SIH), étoilé, comprenant 90% en masse de motifs isoprène hydrogéné et 10% en masse de motifs styrène, de masse Mw égale à 605 000, de masse Mn égale à 439 500, d'indice de polydispersité égal à 1,4, le copolymère commercial est dilué à 10,7% en masse, dans une huile de base de groupe 1,
• une oléfine copolymère (OCP), linéaire, comprenant 50% en masse de motifs éthylène, de masse Mw égale à 171 700, de masse Mn égale à 91 120, d'indice de polydispersité égal à 1,9, le copolymère commercial est dilué à 12,5% en masse, dans une huile de base de groupe 1,
• un paquet comprenant des détergents à base de carboxylates de calcium, de sulfonates de calcium, et de phénates de calcium et un additif anti-usure, le dithiophosphate de zinc (ZnDTP), le paquet étant dilué à 50% en masse, dans une huile de base de groupe 1,
• huiles de base de groupe 1, en particulier bases appelées Neutral Solvant 150NS et 330NS, respectivement de viscosité à 40°C de 30 cSt et 66 cSt.

Composition C ₃ is obtained from the following components:

• a styrene / hydrogenated isoprene (SIH), star-shaped copolymer, comprising 90% by mass of hydrogenated isoprene units and 10% by mass of styrene units, of mass Mw equal to 605,000, of mass Mn equal to 439,500, of index of polydispersity equal to 1.4, the commercial copolymer is diluted to 10.7% by mass, in a group 1 base oil,
• an olefin copolymer (OCP), linear, comprising 50% by mass of ethylene units, of mass Mw equal to 171 700, of mass Mn equal to 91 120, of polydispersity index equal to 1.9, the commercial copolymer is diluted at 12.5% by mass, in a base oil of group 1,
• a package comprising detergents based on calcium carboxylates, calcium sulfonates, and calcium phenates and an anti-wear additive, zinc dithiophosphate (ZnDTP), the package being diluted to 50% by mass, in an oil basic group 1,
• base oils of group 1, in particular bases called Neutral Solvant 150NS and 330NS, respectively with a viscosity at 40 ° C of 30 cSt and 66 cSt.

The amounts in percentages of the various constituents are indicated in tables la and lb below, they are% by mass of the products used in dilution, and not% by mass of active material.

Example 1 : evaluation of the thermal resistance properties of lubricating compositions according to the invention

This involves evaluating the thermal resistance of lubricating compositions according to the invention by carrying out the continuous ECBT test, and thus simulating engine cleanliness in the presence of such compositions.

The following lubricating compositions were tested; the percentages indicated correspond to mass percentages.

Tables Ia and Ib

Table the Compositions C ₁
(comparative) C ₂
(comparative) L ₁
(invention) L ₂
invention L ₃
invention Base oils group 1 64.20 70.20 71.77 - 72.27 Base oils group 2 - - - 65.76 - detergent package 1 - - 16.33 16.33 - detergent package 2 15.80 15.80 - 15.83 Linear hydrogenated styrene / butadiene copolymer (8% by weight in base oil) 20 6.9 6.9 6.9 Olefin copolymer (5% by weight in base oil) - 14 5 - 5 Olefin copolymer (2.3% by weight in base oil) - - - 11.01 - Table Ib Composition C ₃ (comparative) SIH 5 OCP 2.5 Detergent 12.7 ZnDTP 0.5 150NS 27.3 330NS 52.0

The physicochemical characteristics of the compositions of Tables Ia and Ib are described in Table II. Table II Compositions C ₁ (comparative) C ₂ (comparative) L ₁ (invention) L ₂ (invention) L ₃ (invention) C ₃ (comparative) Kinematic viscosity in mm ² / s (measured at 100 ° C according to ASTM D7279) 13.95 13.77 11.06 10.8 10.93 14.30 Kinematic viscosity in mm ² / s (measured at 40 ° C according to ASTM D7279) 87.28 92.24 72.34 66.8 69.69 109.3 Viscosity index (VI) (calculated according to ISO2908) 164.5 152 144 154 147 133 HTHS viscosity (in mPa.s according to ASTM D4683) 3.54 3.54 3.1 3.01 3.07 3.85 BN (measured according to ASTM D2896 in mgKOH / g) 30.1 30.2 29.7 30.5 29.8 29.8

The thermal resistance of the compositions was therefore evaluated using the continuous ECBT test, by which the mass of deposits (in mg) generated under conditions determined. The lower this mass, the better the thermal resistance and therefore the better the engine cleanliness.
This test simulates an engine piston heated to high temperature and onto which lubricant from the crankcase is sprayed.
The test uses aluminum beakers that simulate the shape of pistons. These beakers were placed in a glass container, maintained at a controlled temperature by circulating water at 20 ° C. The lubricant was placed in these containers, themselves equipped with a wire brush, partially immersed in the lubricant. This brush was driven in a rotary motion at a speed of 1000 revolutions per minute, which creates a projection of lubricant on the lower surface of the beaker. The beaker was maintained at a temperature of 310 ° C by an electric resistance heater, regulated by a thermocouple.
In the Continuous ECBT test, the test lasted 12 hours and the lubricant spray was continuous. This procedure simulates the formation of deposits in the piston-ring assembly. The result is the weight of deposits measured on the beaker.
A detailed description of this test is given in the publication entitled “Research and Development of Marine Lubricants in ELF ANTAR France - The relevance of laboratory tests in simulating field performance” by Jean-Philippe ROMAN, MARINE PROPULSION CONFERENCE 2000 - AMSTERDAM - 29-30 MARCH 2000.

The results are collated in Table III below. Table III Compositions C ₁ (comparative) C ₂ (comparative) L ₁ (invention) L ₂ (invention) L ₃ (invention) C ₃ (comparative) Continuous ECBT (mg) (mass deposit beaker) 453 779 471 553 433 600

The results show that the compositions according to the invention exhibit good thermal resistance and thus make it possible to improve engine cleanliness.
It should be noted that the lubricating compositions exhibit improved thermal resistance compared to lubricating compositions comprising an olefin copolymer alone and to lubricating compositions comprising an olefin copolymer in combination with a hydrogenated styrene-isoprene copolymer.

Example 2 : evaluation of the fuel consumption saving properties of lubricating compositions according to the invention

• charge sur la bille de 25N,
• vitesse d'entrainement de 1 m/s,
• SRR (ratio glissement/roulement) de 100%, ce ratio étant équivalent au ratio vitesse de glissement / vitesse de roulement,
• température de 90°C.

Ainsi, dans ces conditions, le coefficient de traction mesuré permet de prédire efficacement le gain en consommation de fuel d'une composition lubrifiante ; plus le coefficient de traction est bas, meilleur est le gain en consommation de fuel.It is a question here of determining, by simulation, the properties of economy of fuel consumption by the use of lubricating compositions according to the invention, by the evaluation of the coefficient of traction on machine MTM (Mini Traction Machine) according to the method described below The tests were carried out on an MTM PCS machine in contact with an ultra-polished 100C6 ball (AISI 52100 standard steel) with a diameter equal to 19.05 mm against a flat disc having the same characteristics of material and surface finish than the balls.
The following conditions have been determined for their representativeness of engine operation in the SPC (Piston Liner Segment) zone, the SPC zone being the engine zone in which most of the friction takes place and therefore the zone in which the gain in consumption of fuel can be maximized:

• load on the ball of 25N,
• drive speed of 1 m / s,
• SRR (slip / rolling ratio) of 100%, this ratio being equivalent to the sliding speed / rolling speed ratio,
• temperature of 90 ° C.

Thus, under these conditions, the measured traction coefficient makes it possible to effectively predict the gain in fuel consumption of a lubricating composition; the lower the traction coefficient, the better the gain in fuel consumption.

The compositions were evaluated according to the above method; the results representing the tensile coefficient of each composition are collated in Table IV. Table IV Compositions C ₁ (comparative) C ₂ (comparative) L ₁ (invention) L ₂ (invention) L ₃ (invention) Coefficient of traction 0.036 0.036 0.032 0.031 0.032

The tensile coefficient for the compositions according to the invention is reduced compared to the comparative compositions C ₁ and C ₂ .
It is therefore observed that the combination of an olefin copolymer and of a hydrogenated linear styrene-butadiene copolymer makes it possible to reduce the coefficient of traction and thus makes it possible to reduce friction.

Example 3 : evaluation of the fuel consumption saving properties of lubricating compositions according to the invention

• Rinçage du moteur et des circuits de lubrification avec le lubrifiant candidat,
• Rodage du moteur avec le lubrifiant candidat,
• Mesure de la consommation en fioul de type distillat (Marine Diesel Oil ― selon la spécification ISO8217). Les mesures sont répétées de façon à s'assurer de la précision,
• Les consommations de fioul obtenues avec le lubrifiant candidat sont comparées avec celles obtenues lorsqu'un lubrifiant de référence est testé dans les mêmes conditions,
• Les conditions d'opération du moteur sont :
  • o Vitesse : 1000 rpm,
  • o Puissance développée : 100%, 75% et 25% de la puissance maximale,
  • o Température du lubrifiant à l'entrée du moteur : 68-70°C,
  • o Volume de lubrifiant : 2 x 200 litres,
• Les tests sont organisés selon un protocole précis qui consiste à encadrer tout essai réalisé avec un lubrifiant candidat entre deux essais réalisés avec le lubrifiant de référence. Cela permet de garantir la stabilité d'opération du moteur ainsi que le caractère statistiquement significatif des différences de consommation mesurées entre lubrifiants,
• Dans le cas présent, le lubrifiant de référence est une huile commerciale pour moteur 4T semi-rapide de grade de viscosité SAE40 et de BN 30.

The fuel-saving properties of the lubricating compositions according to the invention were validated by a test carried out on a bench equipped with a MAN 5L16 / 24 engine. The particular characteristics of this engine have been described in the publication entitled “INNOVATOR-4C, The cuttting-edge MAN B&W 5L16 / 24 test engine”, by D. Lançon, V. Doyen and J. Christensen, CIMAC Congress 2004, KYOTO (Paper 124 ).
A dedicated stabilized regime procedure has been developed to measure the “fuel eco” properties of lubricating compositions according to the description below. This procedure uses equipment that is usually found in engine bench test centers:

• Rinsing the engine and the lubrication circuits with the candidate lubricant,
• Engine break-in with candidate lubricant,
• Measurement of distillate type fuel oil (Marine Diesel Oil - according to ISO8217 specification). The measurements are repeated to ensure accuracy,
• The fuel oil consumptions obtained with the candidate lubricant are compared with those obtained when a reference lubricant is tested under the same conditions,
• The engine operating conditions are:
  • o Speed: 1000 rpm,
  • o Power developed: 100%, 75% and 25% of the maximum power,
  • o Temperature of the lubricant at the engine inlet: 68-70 ° C,
  • o Lubricant volume: 2 x 200 liters,
• The tests are organized according to a precise protocol which consists in supervising any test carried out with a candidate lubricant between two tests carried out with the reference lubricant. This makes it possible to guarantee the operating stability of the engine as well as the statistically significant nature of the differences in consumption measured between lubricants,
• In the present case, the reference lubricant is a commercial oil for semi-rapid 4-stroke engines of viscosity grade SAE40 and BN 30.

The comparative composition C ₃ and the composition according to the invention L ₁ were evaluated. The results, representing the gain in fuel consumption for the various engine loads tested, are collated in Table V. Table V Fuel consumption savings (%) C ₃ (comparative) L ₁ (invention) L ₂ (invention) L ₃ (invention) At 1 00% motor load nd 1.09 1.07 1.29 At 75% engine load 0.7 1.38 1.40 1.13 At 25% motor load nd 2.70 nd 2.72 nd: not determined

It is observed that the combination of a linear hydrogenated styrene / butadiene copolymer and of an olefin copolymer makes it possible, in the lubricating compositions L ₁ , L ₂ and L ₃ , to reduce the consumption of fuel oil by more than 1% at 75 % filler but also at 100% relative to the reference oil unlike composition C ₃ (comparative) comprising the combination of a styrene / hydrogenated isoprene copolymer and an olefin copolymer which only makes it possible to reduce by 0 , 7% fuel oil consumption at 75% load compared to the reference oil.

In addition, it was observed that the general appearance of the engine and crankcases after the test to demonstrate fuel savings show low fouling, in particular with visual ratings of 7.5 out of 10 for crankcase cleanliness and 69.3 out of 100 for piston cleanliness, which is consistent with the reference oil, in particular 4-stroke marine engines, which also have low fouling, in particular with visual ratings of 7.5 out of 10 for cleanliness crankcase and 69.2 out of 100 for piston cleanliness.

Thus, the above examples show that the lubricating compositions according to the invention exhibit both good thermal resistance, and therefore make it possible to improve engine cleanliness, while significantly reducing fuel consumption, in particular fuel oil.

Claims (10)

1. A lubricant composition comprising:

   - at least one base oil;

   - at least one detergent, chosen among detergent of alkaline or alkaline-earth metal salts of carboxylate, sulfonate, salicylate or phenate in an amount being from 10% to 30% by mass based on the total mass of said lubricant composition;

   - 0.01 to 5% by mass based on the total mass of said lubricant composition of at least one olefin copolymer; and

   - 0.01 to 8% by mass based on the total mass of said lubricant composition of at least one hydrogenated and linear styrene/butadiene copolymer.
2. The lubricant composition according to claim 1, wherein the detergent is chosen among carboxylate, sulfonate or phenate detergent.
3. The lubricant composition according to claim 1 or 2, wherein in the hydrogenated and linear styrene/butadiene copolymer, the content of hydrogenated butadiene units ranges from 50% to 98% by moles, preferably from 60% to 98%, more preferentially from 70% to 97%, as compared with the number of moles of hydrogenated and linear styrene/butadiene copolymer.
4. The lubricant composition according to any of claims 1 to 3, wherein the weight content of hydrogenated and linear styrene/butadiene copolymer is from 0.1% to 5% based on the total mass of said lubricant composition, more preferentially from 0.1% to 2%, advantageously from 0.1 to 1%.
5. The lubricant composition according to any of claims 1 to 4, wherein the olefin copolymer is an ethylene-propylene copolymer.
6. The lubricant composition according to claim 5, wherein the ethylene/propylene copolymer comprises a content of ethylene units ranging from 30% to 80% by mass based on the mass of copolymer olefin, preferably from 30% to 70%, more preferentially from 40% to 70%.
7. The lubricant composition according to any of claims 1 to 6, wherein the amount of olefin copolymer is from 0.01% to 2% by mass, based on the total mass of the lubricant composition, preferably from 0.01% to 1%, still more preferentially from 0.1% to 1%.
8. The lubricant composition according to any of claims 1 to 7, wherein the amount of detergents is from 10% to 25% by mass based on the total mass of the lubricant composition, and preferably from 10% to 20%.
9. The use of a lubricant composition according to any of claims 1 to 8 for lubricating 4-stroke or 2-stroke marine engines, preferably 4-stroke engines, or a stationary engine.
10. The use of a lubricant composition according to any of claims 1 to 8 for reducing the fuel consumption while improving the engine cleanliness of 4-stroke or 2-stroke marine engines, preferably 4-stroke engines, or of a stationary engine.