Lubricating fluids based on at least partially re-refined lubricating oils

Abstract

The present application relates to the use of a composition based on at least one at least partially re-refined lubricating oil as a lubricating fluid. It also relates to a method for lubricating and advantageously for lubricating and cooling the members of a propulsion system of an electric or hybrid vehicle, the method comprising at least one step of bringing a composition based on at least one at least partially re-refined lubricating oil into contact with same in the propulsion system.

Description

[0001] Description

[0002] TITLE: LUBRICATING FLUIDS BASED ON AT LEAST PARTIALLY RE-REFINED LUBRICATING OILS

[0003] Technical field

[0004] The present invention relates to the field of lubricating fluids. More specifically, the present invention relates to the use of re-refined lubricating oils for the formulation of a lubricating and possibly cooling fluid for a propulsion system of electric or hybrid vehicles, in particular for the formulation of a single fluid for the lubrication and cooling of a propulsion system of electric vehicles.

[0005] Prior art

[0006] The evolution of international standards for reducing CO2 emissions, but also for reducing energy consumption, is pushing car manufacturers to offer alternative solutions to combustion engines.

[0007] One solution identified by car manufacturers is to replace combustion engines with electric motors. Research into reducing CO2 emissions has therefore led to the development of electric and hybrid vehicles by several car companies.

[0008] Generally speaking, it is necessary to use lubricating compositions, also known as "lubricating fluids", in vehicles for the main purpose of reducing the friction forces between the various parts of the vehicle's propulsion system, in particular between the moving metal parts in the engines. These lubricating compositions are also effective in preventing premature wear or even damage to these parts, and in particular to their surface. Electric motors generate heat during operation. If the amount of heat generated is greater than the amount of heat normally dissipated to the environment, it is necessary to ensure cooling of the motor. Generally speaking, cooling is carried out on one or more parts of the motor that generate heat and / or the parts of the motor that are sensitive to heat, in order to avoid reaching dangerous temperatures.

[0009] This cooling can be done by direct cooling or indirect cooling. Due to the increasing power density of electric motors, it will be necessary to develop and improve the direct cooling method of the electric motor where the lubricating fluid of the transmission part will also serve to cool the hot parts of the electric motor.

[0010] Water is commonly used as a base liquid for coolants due to its natural availability and the lack of environmental impact of its use. In fact, water is an excellent carrier of thermal energy due to its high specific heat capacity, high thermal conductivity, and low viscosity. A significant limitation of using water as a heat transfer fluid is that it freezes at a relatively high temperature of 0°C, making it unsuitable for use in many systems requiring operating temperatures below 0°C. In addition, water-based fluids are naturally corrosive and can cause significant damage to the systems in which they operate.To overcome these limitations, a large number of coolants have been developed in which freezing point depressants are added to the water to lower its freezing temperature, along with various additives to control corrosion.

[0011] Mineral oils derived from petroleum refining have also been proposed as base liquids for coolants, particularly for applications in systems in which the fluid is likely to be heated to high temperatures. A non-aqueous lubricating composition is typically composed of one or more base oils, to which are generally associated several additives dedicated to boosting the lubricating performance of the base oil, for example friction modifier additives.

[0012] However, a large amount of crude oil is generally required to obtain refined oils. Typically, to extract 1 liter of refined oil, 37 liters of crude oil are required. Furthermore, oil refining processes are very energy-intensive. However, current environmental protection and resource conservation issues are pushing manufacturers to offer more eco-friendly alternatives to conventional oils.

[0013] For reasons of economy and ease of implementation, it would be advantageous to have a composition that could simultaneously meet the lubrication and cooling needs of a propulsion system (engine, battery, etc.) of an electric vehicle. Unfortunately, these two properties, lubrication and cooling, impose opposing constraints at first glance.

[0014] A particularly useful type of performance for a lubricating composition in electric vehicle propulsion systems consists of having good mechanical durability properties, properties which are systematically part of the prerogatives to be respected in the manufacturers' specifications.

[0015] In addition, this type of lubricating composition must be able to cool the propulsion systems of electric vehicles, in particular the electric vehicle battery.

[0016] It is therefore an object of the present invention to provide a single fluid (single lubricating composition) which is more environmentally friendly, while having excellent durability and cooling properties and which can be implemented in all the components of a propulsion system of an electric or hybrid vehicle. Description of the invention

[0017] The present invention aims to propose new lubricating fluids meeting these expectations.

[0018] The invention relates to the use of a composition comprising at least one at least partly re-refined lubricating oil as a lubricating fluid for the lubrication of the components of a propulsion system of an electric or hybrid vehicle.

[0019] The invention may have one or more of the following characteristics:

[0020] - the composition is used as a lubricating fluid for the geared motor and as a cooling fluid for the battery; and / or

[0021] - the composition is used as the sole fluid for the lubrication and cooling of all the components of a propulsion system of an electric vehicle; and / or

[0022] - the composition makes it possible to improve the mechanical durability properties, preferably both the mechanical durability properties and the cooling properties; and / or

[0023] - the at least partly re-refined lubricating oil comes from a used lubricant having been subjected to one or more prior stages of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material; and / or

[0024] - the at least partly re-refined lubricating oil comprises one or more polyalphaolefins (PAOs) comprising less than 40 carbon atoms, and preferably comprising 30 carbon atoms; and / or

[0025] - the composition has a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, preferably 15 to 25 mm 2 / s, preferably still from 20.5 to 24 mm 2 / s, or even 21 to 24 mm 2 / s ; and / or

[0026] - the composition comprises: from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a first re-refined lubricating oil having a kinematic viscosity at 40°C ranging from 5 to 20 mm 2 / s, preferably 10 to 16 mm 2 / s, and from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a second re-refined lubricating oil having a kinematic viscosity at 40°C ranging from 21 to 35 mm 2 / s, preferably 25 to 32 mm 2 / s, relative to the total weight of the composition; and / or

[0027] - the composition presents: a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, especially 15 to 25 mm 2 / s, and a thermal conductivity, measured at 90°C and atmospheric pressure, ranging from 115 to 140 mW / mK, in particular from 120 to 130 mW / mK; and / or

[0028] - the composition has a sulfur content of between 0.001% and 0.2% by mass, preferably between 0.01% and 0.2% by mass, relative to the total mass of said at least partly re-refined lubricating oil; and / or

[0029] - the composition has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said at least partly re-refined lubricating oil; and / or

[0030] - the composition has a density less than or equal to 870 kg / m 3 , notably between 830 and 870 kg / m 3 , more particularly between 840 and 860 kg / m3 ; and / or

[0031] - the composition has a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than or equal to 115 mW / mK, more particularly between 115 and 140 mW / mK; and / or

[0032] - the composition has an alkylphenol(s) content of between 5 and

[0033] 3,200 ppm; and / or

[0034] - the composition has an alkylphenol(s) content of between 10 and

[0035] 2,000 ppm, preferably between 15 and 1,500 ppm; and / or

[0036] - the composition has an alkylphenol(s) content of between 10 and 300 ppm, preferably between 15 and 250 ppm; and / or - the composition has an alkylphenol(s) content of between 150 and 2,000 ppm, preferably between 200 and 1,500 ppm; and / or

[0037] - the composition comprises one or more base oils distinct from the at least partly re-refined lubricating oil and / or one or more additives, in particular chosen from anti-corrosion additives, friction modifying additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, and mixtures thereof; and / or

[0038] - the composition comprises more than 80% by mass, in particular between 90% and 100% by mass of one or more lubricating oils at least partly re-refined, relative to the total mass of said composition.

[0039] The invention also relates to a method for lubricating, preferably for lubricating and cooling, the components of a propulsion system of an electric vehicle, comprising at least one step of bringing into contact at the level of said system a composition based on at least one at least partly re-refined lubricating oil, in particular as defined in the invention, in particular having one or more of the following characteristics:

[0040] - the at least partly re-refined lubricating oil comes from a used lubricant having been subjected to one or more prior stages of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material; and / or

[0041] - the at least partly re-refined lubricating oil comprises one or more polyalphaolefins (PAOs) comprising less than 40 carbon atoms, and preferably comprising 30 carbon atoms; and / or

[0042] - the composition has a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, preferably 15 to 25 mm 2 / s, preferably still from 20.5 to 24 mm 2 / s, or even 21 to 24 mm 2 / s ; and / or

[0043] - the composition comprises: from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a first lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 5 to 20 mm 2 / s, preferably 10 to 16 mm 2 / s, and from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a second lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 21 to 35 mm 2 / s, preferably 25 to 32 mm 2 / s, relative to the total weight of the composition; and / or

[0044] - the composition presents: a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, especially 15 to 25 mm 2 / s, and a thermal conductivity, measured at 90°C and at atmospheric pressure, ranging from 115 to 140 mW / mK, in particular from 120 to 130 mW / mK; and / or the composition has an alkylphenol(s) content of between 5 and

[0045] 3,200 ppm; and / or the composition has an alkylphenol(s) content of between 10 and

[0046] 2,000 ppm, preferably between 15 and 1,500 ppm; and / or the composition has an alkylphenol(s) content of between 10 and 300 ppm, preferably between 15 and 250 ppm; and / or the composition has an alkylphenol(s) content of between 150 and 2,000 ppm, preferably between 200 and 1,500 ppm; and / or

[0047] - the composition has a sulfur content of between 0.001% and 0.2% by mass, preferably between 0.01% and 0.2% by mass, relative to the total mass of said at least partly re-refined lubricating oil, and / or

[0048] - the composition has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said at least partly re-refined lubricating oil; and / or - the composition has a density less than or equal to 870 kg / m 3 , notably between 830 and 870 kg / m 3 , more particularly between 840 and 860 kg / m 3 ; and / or

[0049] - the composition has a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than or equal to 115 mW / mK, more particularly between 115 and 140 mW / mK; and / or

[0050] - the composition comprises one or more base oils distinct from the at least partly re-refined lubricating oil and / or one or more additives, in particular chosen from anti-corrosion additives, friction modifying additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, and mixtures thereof; and / or

[0051] - the composition comprises more than 80% by mass, in particular between 90% and 100% by mass of one or more lubricating oils at least partly re-refined, relative to the total mass of said composition.

[0052] More particularly, the inventors have discovered that the recycled lubricating base oils are particularly suitable for use as lubricating fluids to improve the durability of the fluid, more specifically, the inventors have discovered that the recycled lubricating base oils are particularly suitable for use as lubricating fluids and cooling fluids. Thus, the inventors have discovered that the recycled lubricating base oils are particularly suitable for use as a single fluid that can be used in all the components of a propulsion system of an electric vehicle.

[0053] Thus, the invention relates, according to a first of its aspects, to the use of a composition based on at least one at least partly re-refined lubricating oil as a lubricating fluid for the lubrication of the components of a propulsion system of an electric vehicle, preferably as a lubricating fluid and cooling fluid for the lubrication and cooling of the components of a propulsion system of an electric vehicle. In the context of the present invention, the expression "at least partly re-refined lubricating oil", also referred to more simply in the remainder of the text as "re-refined oil", "regenerated oil" or "recycled oil", designates an oil originating at least partly from a used lubricating composition having been subjected to one or more treatment steps known as a re-refining treatment.

[0054] According to the invention, the term "used lubricating composition" (or more simply "used lubricant" or "used lubricating oil") is intended to denote any lubricating composition that has been used for the lubrication of moving parts, in particular metal parts, of a mechanical system, such as, but not limited to, bearings, gears or motors.

[0055] Used lubricating oil can come from different sources. In particular, as detailed in the rest of the text, it can be a lubricant used for the lubrication of a motorization system, in particular "mobile", or for the lubrication of a so-called industrial system, in particular "stationary".

[0056] Due to their origin, used lubricating oils, especially engine lubricating oils, include a number of degradation products derived from the oil itself or the additives it contains, as well as metal particles, metal oxides and other elements, for example from the engine. Used oil may contain, in particular, a high content of undesirable elements, for example calcium (Ca), iron (Fe), magnesium (Mg), sodium (Na), nickel (Ni), phosphorus (P), silicon (Si), chlorine (Cl), zinc (Zn) etc.

[0057] Methods for re-refining or reconditioning used lubricating oils have been developed to regenerate these oils and enable their subsequent reuse.

[0058] A re-refined lubricating oil is thus an oil obtained at the end of one or more stages of treatment of a used lubricant, aimed at eliminating, at least in part, a certain number of contaminating elements present therein, such as dust, water, fuel fractions, metallic elements and other residues resulting from the degradation of the additives present in the lubricant.

[0059] To the inventors' knowledge, it has never been proposed to use a recycled lubricating oil to formulate a lubricating and cooling fluid for the lubrication and cooling of the components of a propulsion system of an electric or hybrid vehicle.

[0060] The use according to the invention of a re-refined lubricating oil as a lubricating fluid, advantageously as a lubricating fluid and cooling fluid, proves to be advantageous in several respects.

[0061] On the one hand, as illustrated in the examples which follow, the inventors have shown that the composition based on one or more re-refined lubricating oils has particularly advantageous durability properties, as well as particularly advantageous thermo-physical properties, in particular in terms of density and thermal conductivity, which make them particularly suitable as lubricating and cooling fluids.

[0062] Surprisingly, recycled lubricating oils even exhibit durability and thermo-physical properties for their use as lubricating and cooling fluids, identical or even superior to those of refined base oils, in other words virgin or new base oils.

[0063] A refined base oil, also called "virgin" or "new" base oil, unlike re-refined lubricating oils, is an oil directly derived from petroleum refining and which has not yet been used.

[0064] On the other hand, advantageously, the implementation of recycled lubricating oils as lubricating fluids meets current expectations for reducing environmental impact and conserving resources. Thus, the use of lubricating fluids based on regenerated lubricating oils advantageously reduces the carbon footprint of products, compared to the use of virgin base oils. In addition, the use of a single fluid to both lubricate and cool the components of a propulsion system of an electric or hybrid vehicle also reduces the carbon footprint.

[0065] As detailed in the remainder of the text, said re-refined lubricating oil(s) may be used as such, i.e. alone, in other words without additives, as a lubricating fluid. In a particular embodiment, the invention thus relates to the use of at least one at least partly re-refined lubricating oil as a lubricating fluid for the lubrication of the components of a propulsion system of an electric or hybrid vehicle, preferably an electric vehicle.

[0066] Said re-refined lubricating oil(s) may still be used in combination with one or more other ingredients. In particular, they may be supplemented with one or more additives, for example intended to promote the compatibility of the lubricating fluid with the materials of the system for which it is intended, such as, for example and without limitation, anti-corrosion additives, antioxidant additives, etc.

[0067] In the context of this embodiment variant, the lubricating fluid according to the invention is advantageously formed mainly from said re-refined lubricating oil(s). In particular, said re-refined lubricating oil(s) may represent more than 80% by mass of the total mass of the lubricating fluid, in particular more than 90% by mass of the total mass of the lubricating fluid.

[0068] Said re-refined lubricating oil(s) may also be used in combination with at least one new base oil.

[0069] The present invention also relates to the use of at least one at least partially re-refined lubricating oil for formulating or preparing a lubricating fluid for the lubrication of the components of a propulsion system of an electric or hybrid vehicle.

[0070] The present invention also relates to the use of at least one at least partially re-refined lubricating oil for formulating or preparing a lubricating and cooling fluid, also called a single fluid, for the lubrication and cooling of the components of a propulsion system of an electric or hybrid vehicle.

[0071] The present invention also relates to a process or method for preparing a lubricating fluid, in particular a lubricating and cooling fluid, comprising at least one step of obtaining an at least partly re-refined lubricating oil from a used lubricant.

[0072] The process for preparing a lubricating fluid according to the invention, in particular a lubricating and cooling fluid, may more particularly comprise the steps consisting of:

[0073] (i) preparing one or more at least partly re-refined lubricating oil(s) from a used lubricant;

[0074] (ii) optionally, mixing said at least partly re-refined lubricating oil(s) with one or more new base oils, distinct from re-refined lubricating oils, for example one or more mineral oils; and

[0075] (iii) optionally, supplementing said at least partly re-refined lubricating oil(s) from step (i), or the mixture of lubricating oils from step (ii), with at least one additive, in particular chosen from anti-corrosion additives, friction modifier additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, and mixtures thereof.

[0076] The invention also relates, according to another of its aspects, to the use of a lubricating fluid according to the invention, based on at least one at least partly re-refined lubricating oil, as the sole fluid for the lubrication and cooling of all the components of a propulsion system of an electric vehicle.

[0077] Furthermore, the invention also relates, according to another of its aspects, to the use of a lubricating fluid according to the invention, based on at least one at least partly re-refined lubricating oil, as lubricating fluid for the geared motor and as cooling fluid for the battery of a propulsion system of an electric vehicle.

[0078] The invention also relates to the improvement of mechanical durability properties, preferably the improvement of both mechanical durability properties and cooling properties by the use of a composition comprising one or more at least partly re-refined lubricating oils as defined in the present invention.

[0079] Other characteristics, variants and advantages of the use of at least partly re-refined lubricating oils for the formulation of a lubricating fluid according to the invention will become more apparent upon reading the description and examples which follow, given by way of illustration and not limitation of the invention.

[0080] The expressions "between ... and ...", "ranging from ... to ...", "formed from ... to ...", and "varying from ... to ...", must be understood inclusively, unless otherwise stated.

[0081] In the description and examples, unless otherwise indicated, percentages are percentages by mass. The percentages are therefore expressed by mass relative to the total mass of the composition.

[0082] Brief description of the figures

[0083] Figure 1 represents the two-dimensional chromatogram of a first re-refined lubricating oil according to the invention, oil I2 of the experimental part.

[0084] Figure 2 represents the two-dimensional chromatogram of a second re-refined lubricating oil according to the invention, oil 11 of the experimental part.

[0085] Figure 3 represents the two-dimensional chromatogram of another re-refined lubricating oil according to the invention, different from oils 11 and 12 of the experimental part.

[0086] Detailed description Lubricating oil at least partly re-refined

[0087] As previously specified, the oil used to formulate a lubricating fluid according to the invention is a lubricating oil that is at least partly re-refined, also called “regenerated oil” or “recycled oil”, in other words a lubricating oil from a used lubricating composition that has been subjected to one or more re-refining treatment steps can be used according to the invention.

[0088] It is understood that a used lubricating composition may be a mixture of several used lubricating compositions, from the same source or from several different sources.

[0089] Used lubricating compositions and, consequently, regenerated lubricating oils, comprise, in the majority quantity, one or more base oils conventionally used in the field of lubricants, such as mineral, synthetic or natural, animal or vegetable oils or their mixtures.

[0090] It can be a mixture of several base oils, for example a mixture of two, three, or four base oils.

[0091] These base oils may be of natural origin, for example from plants or animals, such as vegetable, animal, fish oils, and mixtures thereof. Examples of such oils are rapeseed oil, canola oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, animal fats, and mixtures thereof.

[0092] Advantageously, these base oils are oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in the following table, or their mixtures.

[0093] [Table 1]

[0094] In particular, the used lubricating composition, from which the regenerated lubricating oil used according to the invention is derived, may comprise at least 50% by weight of base oil(s) relative to its total weight, in particular at least 60% by weight of base oil(s), and more particularly between 60 and 99% by weight of base oil(s).

[0095] The re-refined lubricating oils used according to the invention advantageously have characteristics in terms of content of saturated compounds, sulfur content and viscosity index, satisfying the criteria defined by the API classification for oils of groups I, II, III, IV and / or V, in particular for oils of groups I, II, III and / or IV.

[0096] The invention thus aims at the use as a lubricating fluid of a composition formed in whole or in part from at least one lubricating oil at least partly re-refined, obtained at the end of one or more stages of treatment of a used lubricant based on one or more oils from groups I to V according to the API classification.

[0097] According to a particular embodiment, the re-refined lubricating oil used according to the invention may come from the treatment of a used lubricating composition having been used for the lubrication of a motorization system, in particular “mobile”, that is to say including light vehicles, heavy goods vehicles, so-called “off-road” mobile machines, or even marine vehicles.

[0098] According to another particular embodiment, the re-refined lubricating oil used according to the invention may come from the treatment of a used lubricating composition having been used for the lubrication of a so-called industrial system, in particular “stationary”, that is to say including, in a non-limiting manner, turbines, compressors, hydraulic systems, gears, or even forming or cutting machines.

[0099] A used lubricating composition, from which the reclaimed lubricating oil used according to the invention is derived, may contain various conventional additives in the field of lubricants, such as friction modifier additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant (PPD) additives, dispersing agents, anti-foaming agents, thickeners, and mixtures thereof.

[0100] As already mentioned above, the properties of the used lubricating composition are degraded due to its use, for a more or less long period, for the lubrication and / or cooling of a mechanical system, in particular a motorization system, such as a combustion engine.

[0101] Due to their origin, used lubricating compositions may thus contain one or more additives described above and impurities resulting from the degradation of additives originally present in the lubricant, or resulting from the wear of moving mechanical parts.

[0102] The composition of used lubricant can of course vary depending on the origin of the lubricant, its initial formulation and the fact that it may have been contaminated differently depending on its use.

[0103] The regenerated lubricating oil used according to the invention comes more particularly from a used lubricating composition having been subjected to one or more prior pre-treatment steps known in the field of re-refining used lubricants.

[0104] In particular, these treatment steps aim to remove, at least partially, water, solid particles, fuel and / or other contaminants, such as polycyclic aromatic hydrocarbons (PAHs), which are undesirable in the formulation of lubricants.

[0105] According to one embodiment, a re-refined lubricating oil implemented in the present invention comprises one or more alkylphenols. By "alkylphenol" is meant a phenolic compound with an alkyl group R 1 in the para position, and therefore of formula R 1 -C 6 H 4 -OH. The presence of alkylphenol is then characteristic of re-refined lubricating oils, given that native (unused) oils do not comprise alkylphenol.

[0106] Preferably, the content of alkylphenol(s) in the re-refined lubricating oil according to the present invention is between 5 and 3,200 ppm.

[0107] A re-refined lubricating oil used in the present invention may for example comprise from 10 to 2000 ppm, preferably from 15 to 1500 ppm, of alkylphenol(s).

[0108] According to one embodiment, a re-refined lubricating oil implemented in the present invention comprises from 10 to 300 ppm, preferably from 15 to 250 ppm, of alkylphenol(s).

[0109] According to one embodiment, a re-refined lubricating oil implemented in the present invention comprises from 150 to 2000 ppm, preferably from 200 to 1500 ppm, of alkylphenol(s).

[0110] The alkylphenol(s) content in re-refined lubricating oil can be measured according to the method described in the patent application filed under number FR2315133. This method is based on the implementation of liquid chromatography and mass spectrometry steps, using a standard compound which is 4-hexadecylphenol.

[0111] For the liquid chromatography steps, a particle-filled column composed of C8-bonded silica is used. Measurements are carried out at 40°C with a flow rate of 0.4 mL / min.

[0112] Here, a so-called reversed-phase column is used to separate the different components of the sample (here, re-refined lubricating oil to be analyzed) according to their polarity. The composition of the mobile phase is used to modify these interactions over time and thus gradually elute the different molecules of the sample analyzed (here, re-refined lubricating oil).

[0113] The mobile phase is used in the form of a gradient as shown in the table below, from a solution A comprising 50% water and 50% acetonitrile and a solution B comprising 100% methanol.

[0114] Using mass spectrometry detection, it is then possible to obtain the signal produced only by the molecules of interest, identified both by their mass and their retention time.

[0115] The ionization source used is preferably the electrospray ionization (ESI) source which allows the selective ionization of polar compounds. In the case of the method used here, the detection mode chosen is the negative detection mode because it allows the selective ionization of polar compounds with an acidic character. The range for mass / charge ratios (m / z) varies from 100 to 1200.

[0116] In particular, the method for measuring the alkylphenol content in the re-refined lubricating oil implemented in the present invention comprises a first step of preparing the standard solution (4-hexadecylphenol) and the solution to be analyzed (re-refined lubricating oil):

[0117] - preparation of a standard solution at different concentrations to obtain a calibration line as explained later, by dilution in THF with the addition of 2% ammonium hydroxide; and

[0118] - preparation of a solution of said re-refined lubricating oil by dilution in tetrahydrofuran (THF) with the addition of 3% ammonium hydroxide.

[0119] To establish the calibration curve, the intensity of the chromatographic peak associated with the 4-hexadecylphenol ion of the standard is recovered by plotting an extracted ion chromatogram (EIC). This allows to have an extracted chromatogram only for a given m / z ratio, namely here 317.28 for the standard molecule, the deprotonated form corresponding to the ion [C22H37O]'. The intensity of the EIC is therefore recovered for each of the analyses at the different concentrations tested.

[0120] The data obtained allow the construction of the calibration line. This calibration line is obtained by injecting several standard solutions at different concentrations: the line is constructed by linear regression, and the calculation of the correlation coefficient (R 2) allows to check the linearity of the detector and the correct preparation of the standard solutions.

[0121] The associated equation then allows us to predict the concentration of an unknown sample by entering the experimentally obtained y value. Here, the equation is: y = 1001.9x - 15309

[0122] To quantify the alkylphenols in the re-refined lubricating oil used in the present invention, the analysis method comprises a step of identifying the m / z ratios of the alkylphenol residues on the average mass spectrum by integrating the entire chromatogram. This average spectrum corresponds to an average of all the mass spectra obtained on the complete chromatographic run. This makes it possible to have all the compounds that were ionized during the analysis. From this average mass spectrum is extracted a mass list grouping together all the m / z ratios of the ions with the associated intensities.

[0123] The next step is to construct a Kendrick diagram with this mass list. This is a molecular map that allows us to identify series of compounds of the same type, but with different degrees of alkylation, by overcoming the mass defect of the hydrogens in the CH2 motif.

[0124] The Kendrick diagram can be made by calculating the following values:

[0125] 14,00000

[0126] KM=mass (IUPAC or EXPER)x — — v 7 14.01565 where KM corresponds to the Kendrick mass, IUPAC mass corresponds to the theoretical mass calculated from the sum of each element constituting the molecule of interest, here for the standard molecule hexadecylphenol of formula [C22H37O] the IUPAC mass = 317.284440 g.moh 1 , and EXPER mass corresponds to an experimental mass measurement, measured during an experiment.

[0127] The Kendrick mass KM is calculated for each peak of the average mass spectrum, determined previously as explained above.

[0128] Then, the Kendrick MKD mass defect is typically calculated according to the following equation:

[0129] KMD = NKM - KM where KMD corresponds to the Kendrick mass defect,

[0130] KM corresponds to the Kendrick mass, and

[0131] NKM is the nearest integer rounding of the Kendrick mass KM.

[0132] The Kendrick mass defect KMD is calculated for each peak (each peak corresponding for example to a compound present in re-refined lubricating oil). Kendrick diagrams correspond to a 2D molecular map representing KMDs as a function of NKMs. Homologous compounds varying in their degree of alkylation appear as a horizontal line.

[0133] The set of m / z ratios of the alkylphenols is obtained by applying a filter on the y-axis (KMD): this is the value KMD = 0.069. Once all the m / z ratios at KMD = 0.069 are identified, they are used to construct extracted ion chromatograms (EIC) as described for the standard molecule. This makes it possible to have a chromatogram dependent only on the requested m / z ratio. The intensities of the EIC of each m / z ratio corresponding to the alkylphenols are thus summed to have the total intensity (several alkylphenol type molecules are obtained on the spectra of re-refined lubricating oil used in the present invention, these molecules varying by the length of their alkyl chain).

[0134] To obtain a quantification, the sum of the intensities of the obtained EICs is used as the value of y for the equation of the calibration line. For example, if the obtained value is 2.45 E6, the quantification of alkylphenol residues in the re-refined lubricating oil I2 of the experimental part is: y = 1001,9x - 15309

[0135] > y + 15309 X" 1001 ,9 and therefore x is equal to 2460.6 ppm.

[0136] According to one embodiment, a re-refined lubricating oil implemented in the present invention comprises one or more polyalphaolefins (PAOs). The presence of polyalphaolefin(s) is then characteristic of re-refined lubricating oils, given that native (unused) oils do not comprise polyalphaolefins (PAOs).

[0137] Figures 1 to 3 represent two-dimensional chromatograms of three re-refined lubricating oils according to the present invention. The arrow in each of the figures indicates the characteristic peak of PAO (at C30), a marker of re-refined oils.

[0138] According to one embodiment, a re-refined lubricating oil implemented in the present invention comprises one or more polyalphaolefins (PAOs) comprising less than 40 carbon atoms, and preferably comprising 30 carbon atoms.

[0139] The presence of PAOs in re-refined lubricating oil can be determined, for example, using a method based on the implementation of comprehensive two-dimensional gas chromatography (GC x GC) and classification steps.

[0140] In particular, it is implemented via a chromatography device, the chromatography device comprising a comprehensive two-dimensional gas chromatography module comprising a first column A and a second column B, and capable of separating different compounds of the product according to their volatility and their polarity, the chromatography device further comprising a flame ionization detector capable of measuring an intensity of electric ionization current generated for each compound included in the product, the chromatography device being calibrated with at least one calibration product, making it possible to correct the retention time of the different compounds present in the product.

[0141] The method is further implemented by an electronic classification device, comprising the following steps: a. determining a table describing the intensity of the electric ionization current generated for each compound included in the product as a function of the corrected retention times in columns A and B, from a measurement carried out by the chromatography device on the product; b. assigning a class to the product, from among a plurality of classes, by applying a multivariate statistical algorithm to the table, said algorithm being trained on tables obtained from reference products. The chromatography device comprises a comprehensive two-dimensional gas chromatography module comprising a first column A and a second column B. The comprehensive two-dimensional gas chromatography modules (2D GC or GC x GC) that can be used in the context of the present disclosure are those described in the literature.

[0142] These modules generally include an injection module, a vaporization module, a first column A, a modulator, and a second column B. They allow a two-dimensional separation of complex mixtures, because the product is subjected to two separations, we then obtain a two-dimensional chromatogram as a function of the retention times of columns A and B and a table describing the intensity of the electric ionization current generated for each compound included in the product as a function of the corrected retention times in columns A and B.

[0143] According to one embodiment, the first column A and the second column B are columns based on polydimethylsiloxane partially functionalized with phenyl groups. The percentage of functionalization with phenyl groups can be between 2% and 50%.

[0144] According to a particular embodiment, the percentage of functionalization in phenyl group of column A is greater than the percentage of functionalization in phenyl group of column B.

[0145] Advantageously, the length of column A is greater than that of column B.

[0146] The diameter of the two columns A and B can be equivalent.

[0147] Both columns can have a film thickness of 0.1 pm suitable for the separation of low volatile samples.

[0148] According to one embodiment, the temperature gradient applied to the furnace is 2°C / min up to 400°C. A quantity of product is injected into the first column A to obtain a first separation, then via the modulator, into the second column B to obtain a second separation. The product can be injected directly without pretreatment, particularly in the case of lubricating oil analysis.

[0149] The GC x GC device is coupled to a flame ionization detector (FID). This is capable of measuring the intensity of the ionization electric current generated for each compound included in the product. The flame ionization detector is located at the outlet of the second column.

[0150] Following analysis by the flame ionization detector, a table describing the intensity of the ionization electric current generated for each compound included in the product, as a function of the corrected retention times in columns A and B, is determined. The table is therefore derived from a two-dimensional chromatogram obtained from a measurement carried out by the chromatography device on the product.

[0151] In addition, during this initial step, an external calibration is carried out to correct the retention time of the various compounds present in the product. This is carried out by injecting at least one calibration product. If the product to be classified is a lubricating oil, the calibration product may be a lubricating oil, preferably recycled.

[0152] According to one embodiment, the calibration product comprises at least one marker, preferably at least two markers. The marker can be selected from n-paraffins, polyalphaolefins, and their mixture. The correction of the retention times can be carried out by software.

[0153] At the end of this initial step, the classification device moves on to a next step, during which it assigns, via its product assignment module, a respective class from among the plurality of classes, by applying a multivariate statistical algorithm to the table, said algorithm being trained on tables obtained from reference products. The multivariate statistical algorithm used during the assignment step may be a multivariate statistical algorithm by partial least squares regression; the multivariate statistical algorithm preferably being chosen from the group consisting of: a partial least squares regression algorithm, and a partial least squares regression algorithm with discriminant analysis. The algorithm is typically a partial least squares regression algorithm, such as the PLS algorithm or the PLS-DA algorithm.

[0154] The multivariate statistical algorithm used during the attribution step is trained on tables obtained from reference products.

[0155] In Partial Least Squares Discriminant Analysis (PLS-DA), the prediction coefficient on a scale of 0 to 1 represents the probability or confidence of a sample belonging to a particular class.

[0156] Here is how this coefficient is calculated and used:

[0157] 1. Creation of latent variables:

[0158] PLS-DA creates latent variables (components) that capture the maximum variance of the X data (the predictors) while maximizing the covariance with the Y classes (the categorical responses).

[0159] 2. Calculation of scores:

[0160] Samples are projected onto these latent variables, producing scores that are used to discriminate between classes.

[0161] 3. Modeling:

[0162] A linear model is fitted to these scores to predict values ​​of Y. In the case of PLS-DA, Y is often binary encoded to represent classes (e.g., 0 for group A and 1 for group B).

[0163] 4. Prediction: When predicting for new samples, the scores of these samples are calculated and passed through the linear model to obtain a continuous prediction. This continuous prediction is then transformed into a probability on a scale of 0 to 1.

[0164] 5. Interpretation of probabilities:

[0165] These probabilities are then interpreted to assign the samples to the different classes.

[0166] For example :

[0167] - if the probability is strictly less than 0.4, the sample is classified in group A (here group of re-refined base oils); and

[0168] - if the probability is greater than or equal to 0.4, the sample is classified in group B (conventional base oil group).

[0169] According to a particular embodiment, the regenerated lubricating oil used according to the invention comes from a used lubricant having been subjected to one or more prior steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material, preferably as detailed below.

[0170] Thus, the invention relates to the use, as a lubricating fluid, in particular for the lubrication of the components of a propulsion system of an electric vehicle, of a composition based on at least one at least partly re-refined lubricating oil, in particular formed from at least one at least partly re-refined lubricating oil, preferably as described above, said at least partly re-refined lubricating oil being obtained from a used lubricating composition having been subjected to at least one or more steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of said used lubricating composition over an adsorbent material, preferably carried out under the conditions detailed below.

[0171] Thus, the invention relates to the use, as a lubricating and cooling fluid, in particular for the lubrication and cooling of the components of a propulsion system of an electric vehicle, of a composition based on at least one at least partly re-refined lubricating oil, in particular formed from at least one at least partly re-refined lubricating oil, preferably as described above, said at least partly re-refined lubricating oil being obtained from a used lubricating composition having been subjected to at least one or more steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of said used lubricating composition over an adsorbent material, preferably carried out under the conditions detailed below.

[0172] Thus, the invention relates to the use, as a single fluid for the lubrication and cooling of the components of a propulsion system of an electric vehicle, of a composition based on at least one at least partly re-refined lubricating oil, in particular formed from at least one at least partly re-refined lubricating oil, preferably as described above, said at least partly re-refined lubricating oil being obtained from a used lubricating composition having been subjected to at least one or more steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of said used lubricating composition over an adsorbent material, preferably carried out under the conditions detailed below.

[0173] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one dehydration step. This dehydration step makes it possible to eliminate any water possibly present in the used lubricant.

[0174] Advantageously, the regenerated lubricating oil used according to the invention thus comprises a water content of less than or equal to 10% by mass, in particular less than or equal to 5% by mass, in particular less than or equal to 2% by mass and more particularly less than or equal to 1% by mass, relative to the total mass of said regenerated lubricating oil. This dehydration can be carried out by any method known to those skilled in the art, for example by distillation, evaporation, decantation, heating or passing a flow of hot air through the used lubricating composition.

[0175] According to one embodiment, the dehydration step can be carried out at a temperature between 50°C and 250°C, preferably between 100°C and 200°C. In particular, it can be carried out at a pressure between 50,000 and 150,000 Pa, preferably at atmospheric pressure.

[0176] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one prior filtration step. This filtration can be carried out by any method known to those skilled in the art. This filtration step can be a particulate or non-particulate filtration step. It can, for example, be carried out by diatomaceous earth type systems.

[0177] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one distillation step, preferably following a prior dehydration step. Said distillation step(s) may be carried out by any technique known to those skilled in the art. It may be, for example, atmospheric distillation or distillation under reduced pressure. The distillations may, for example, be carried out at a temperature of between 100°C and 500°C, preferably between 200°C and 400°C, more preferably between 300°C and 380°C. In particular, they may be carried out at a pressure of between 25 and 2,000 Pa, preferably between 50 and 1,000 Pa, more particularly between 50 and 250 Pa.

[0178] Advantageously, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one prior step of passing said used lubricating composition over an adsorbent material. The adsorbent material advantageously makes it possible to selectively adsorb aromatic compounds, in particular PAHs.

[0179] In particular, passing over an adsorbent material, preferably over activated carbon, advantageously makes it possible to reduce the content of polycyclic aromatic hydrocarbons (PAHs), notably chosen from chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, dibenz[a,h]anthracene and / or benz[a]anthracene, of the used lubricating composition.

[0180] The term "passage of the used lubricating composition over an adsorbent material" means the flow of the used lubricating composition over the adsorbent support.

[0181] The adsorbent materials can be, for example, activated carbon, zeolites, clays or functionalized porous compounds. Preferably, it is activated carbon.

[0182] For example, the regenerated lubricating oil used in the method of the invention can be obtained from the treatment of a used lubricating composition according to the method described in document WO 2018 / 109208.

[0183] In the case of passing the used lubricating composition over activated carbon, the quantity of activated carbon used is preferably between 0.5 and 60 g of activated carbon per liter of used lubricating composition, preferably between 0.5 and 50 g / L, preferably from 1 to 50 g / L, preferably between 1 and 30 g / L, for example between 5 and 60 g / L, preferably between 5 and 50 g / L.

[0184] The flow rate of the used lubricating composition can be between 1 and 15 m 3 / h, for example between 5 and 10 m 3 / h.

[0185] Preferably, the activated carbon is characterized by a density between 200 and 500 kg / m 3 , for example measured according to ASTDM D2854.

[0186] Preferably, the activated carbon is a coal, preferably comprising from 70 to 95%, advantageously from 80 to 90% by weight of carbon. The step of passing the used lubricating composition onto an adsorbent support, preferably onto activated carbon, is advantageously preceded by the following preliminary steps:

[0187] - one or more distillation stages; and

[0188] - a filtration step, in particular as defined previously.

[0189] Advantageously, the regenerated lubricating oil used according to the invention can be obtained by subjecting a used lubricating composition to at least one prior hydrogenation (or hydrotreatment) step, preferably which follows a prior dehydration and / or distillation step. Said hydrogenation step(s) can be carried out by any technique known to those skilled in the art and generally consist of treating the lubricating oil with hydrogen, generally in the presence of a hydrotreatment catalyst. Such a catalyst can contain, for example, at least one oxide or sulfide of at least one group VI metal and / or at least one group VIII metal, such as molybdenum, tungsten, nickel or cobalt, and a support, for example alumina, silica-alumina or a zeolite.

[0190] Advantageously, the regenerated lubricating oil used according to the invention can be obtained by subjecting a used lubricating composition to at least one prior step of liquid / liquid extraction by a solvent, preferably which follows a prior step of dehydration and / or distillation. In particular, the liquid / liquid extraction by a solvent advantageously makes it possible to lighten a dark-colored used oil, to eliminate at least in part the bad odor or the aromatic compounds, in particular the PAHs. Said extraction step(s) can be implemented by any technique known to those skilled in the art. The extraction is generally carried out in a mixer-settler or in an extraction column, using a suitable extraction solvent.

[0191] Advantageously, the regenerated lubricating oil used according to the invention can be obtained by subjecting a used lubricating composition to at least one prior decantation step. Said decantation step(s) can be carried out by any technique known to those skilled in the art. It is understood that the invention is in no way limited to the use of regenerated oils obtained according to the treatment methods described above. Other at least partly re-refined lubricating oils, for example group I and / or II, resulting from treatment steps different from those described above, may be suitable for the invention.

[0192] In any event, a re-refined lubricating oil used according to the invention is distinguished from a used lubricating oil, in particular due to the reduced content of certain undesirable contaminating elements, for example water, fuel, metallic elements or even certain heteroatoms.

[0193] A regenerated lubricating oil used according to the invention is notably characterized by a silicon content of between 0 and 300 ppm, notably between 1 and 300 ppm.

[0194] A regenerated lubricating oil used according to the invention is in particular characterized by a phosphorus content of less than or equal to 100 ppm, in particular between 0 and 100 ppm, for example 0 ppm.

[0195] A regenerated lubricating oil used according to the invention may also be characterized by its content of one or more other elements chosen from chlorine, oxygen and nitrogen. It may, for example, have a chlorine content of between 0 and 50 ppm, for example 0 ppm.

[0196] The content of these elements can be assessed by any method known to those skilled in the art, for example by X-ray fluorescence (XRF), or by infrared or ultraviolet spectroscopy.

[0197] On the other hand, a regenerated lubricating oil used according to the invention is distinguished, due to its formation from a used lubricant, from a virgin or new base oil, oil directly derived from petroleum refining, or from native base oils, for example of natural origin, both in terms of its composition and its physicochemical properties. In particular, as indicated above, surprisingly, a regenerated lubricating oil has excellent thermophysical and hydraulic properties, in particular in terms of viscosity index, density, Noack volatility, flash point and / or thermal conductivity, and advantageously thermophysical and hydraulic properties superior to those of a virgin base oil.

[0198] Preferably, the kinematic viscosity measured at 100°C according to the ASTM D445 standard of the at least partly re-refined lubricating oil is greater than or equal to 3 mm 2 / s, for example between 3 and 10 mm 2 / s, especially between 3 and 8 mm 2 / s.

[0199] Advantageously, the at least partly re-refined lubricating oil used according to the invention has a kinematic viscosity measured at 40°C according to the ASTM D445 standard of between 10 and 40 mm 2 / s, especially between 12 and 30 mm 2 / s.

[0200] Preferably, an at least partly re-refined lubricating oil used according to the invention has a viscosity index greater than or equal to 110. The viscosity index of the at least partly re-refined lubricating oil can thus be between 110 and 130, in particular between 112 and 125.

[0201] The viscosity index can in particular be determined according to standard NF ISO 2909.

[0202] Preferably, a regenerated lubricating oil used according to the invention has a Noack volatility of less than or equal to 15%, or even strictly less than 12%. The Noack volatility of the at least partly re-refined lubricating oil can thus be between 8% and 15%, or even between 8% and 11.9%.

[0203] Noack volatility can be determined according to CEC L-40-93 at 250°C.

[0204] Preferably, a regenerated lubricating oil used according to the invention has a sulfur content of between 0.001% and 0.2% by mass, preferably between 0.01% and 0.2% by mass, relative to the total mass of said regenerated lubricating oil. Preferably, a regenerated lubricating oil used according to the invention has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, relative to the total mass of said regenerated lubricating oil. The content of aromatic compound(s) in the regenerated lubricating oil may thus be between 1% and 25% by mass, in particular between 2.5% and 20% by mass, relative to the total mass of said regenerated lubricating oil.

[0205] The contents of these different elements can be determined using any method known to those skilled in the art, for example by X-ray fluorescence (XRF) or by infrared or ultraviolet spectroscopy.

[0206] At least one re-refined lubricating oil used according to the invention advantageously has at least one, at least two, at least three, or even all of the following characteristics:

[0207] - a kinematic viscosity measured at 100°C according to standard ASTM D445 greater than or equal to 2 mm 2 / s, for example between 2 and 12 mm 2 / s, more particularly between 3 and 10 mm 2 / s ;

[0208] - a viscosity index greater than or equal to 100, in particular between 105 and 130, in particular between 105 and 125;

[0209] - a Noack volatility less than or equal to 40%, in particular between 8% and 40%, more particularly between 10% and 38%;

[0210] - a sulfur content of between 0.001% and 0.2% by mass, preferably between 0.01% and 0.2% by mass, in particular between 0.015% and 0.1% by mass, relative to the total mass of said regenerated lubricating oil;

[0211] - a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular between 1% and 25% by mass, relative to the total mass of said regenerated lubricating oil;

[0212] - a silicon content ranging from 2 to 60 ppm, preferably from 4 to 50 ppm by mass, relative to the total mass of said regenerated lubricating oil.

[0213] Advantageously, a regenerated lubricating oil used according to the invention has a density less than or equal to 870 kg / m 3 , in particular less than or equal to 860 kg / m 3The density of the at least partly re-refined lubricating oil can thus be between 830 and 870 kg / m 3 , particularly between 840 and 860 kg / m 3 .

[0214] The density can in particular be determined according to standard NF EN ISO 12185 at 15°C.

[0215] Advantageously, a regenerated lubricating oil used according to the invention has a flash point greater than or equal to 180°C, in particular greater than or equal to 182°C. The flash point of the at least partly re-refined lubricating oil can thus be between 182°C and 245°C.

[0216] The flash point can in particular be determined according to standard NF EN ISO 2592.

[0217] Advantageously, a regenerated lubricating oil used according to the invention has a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than or equal to 115 mW / mK, in particular greater than or equal to 120 mW / mK. The thermal conductivity of the at least partly re-refined lubricating oil can thus be between 120 and 145 mW / mK, in particular between 125 and 145 mW / mK.

[0218] Thermal conductivity can be determined in particular according to ASTM D7896-19.

[0219] Due to these properties in terms of viscosity index, density, thermal conductivity, flash point, Noack volatility and density, the re-refined lubricating oils used according to the invention exhibit excellent performance both in terms of mechanical durability, cooling efficiency and hydraulic performance, and advantageously increased performance compared to virgin base oils.

[0220] A high viscosity index makes it possible in particular to have a lubricating fluid whose viscosity varies little with temperature, thus ensuring good hydraulic properties of the lubricating fluid. Thus, the lubricating fluid according to the invention can be used in systems which may be subject to large temperature variations, for example as a lubricating fluid, advantageously as a lubricating and cooling fluid, in vehicles, and remains pumpable over the temperature range in which it must circulate in said system.

[0221] In particular, re-refined lubricating oils advantageously have a low density, in particular lower than that of virgin base oils, and a high viscosity index, in particular higher than that of virgin base oils, which allows for reduced pumping costs, while having better thermal properties.

[0222] Lubricating fluid

[0223] As mentioned above, said re-refined lubricating oil(s) used according to the invention, in particular as defined and characterized above, can be used as such as a lubricating fluid, or be formulated in a composition intended to be used as a lubricating fluid.

[0224] As mentioned above, said re-refined lubricating oil(s) used according to the invention, in particular as defined and characterized above, can be used as such as a lubricating and cooling fluid, or be formulated in a composition intended to be used as a lubricating and cooling fluid.

[0225] The composition used as a lubricating fluid, advantageously as a lubricating and cooling fluid, may thus comprise one or more base oils distinct from the at least partly re-refined lubricating oil and / or one or more additives.

[0226] In a particular embodiment, said re-refined lubricating oil(s) may be formulated in combination with one or more distinct base oils, in particular one or more new base oils. The new base oils are in particular chosen from base oils conventionally used in the field of lubricants, such as mineral, synthetic or natural, animal or vegetable oils or mixtures thereof.

[0227] Advantageously, these base oils are oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in table 1 above, or their mixtures.

[0228] A composition implemented according to the invention may thus comprise, or even be formed from, a mixture of one or more at least partly re-refined lubricating oils and one or more new base oils, for example at least one mineral oil.

[0229] In particular, a composition used according to the invention may comprise between 0% and 80% by mass, in particular between 5% and 75% by mass of new base oil(s), distinct from re-refined lubricating oils required according to the invention and defined above, relative to the total mass of the composition.

[0230] According to a particular embodiment, a composition used as a lubricating fluid, advantageously as a lubricating and cooling fluid, according to the invention comprises less than 50% by mass of new base oil(s), distinct from re-refined lubricating oils, relative to the total mass of the composition.

[0231] Preferably, a composition used as a lubricating fluid according to the invention is formed mainly from said re-refined lubricating oil(s).

[0232] Thus, a composition used as a lubricating fluid according to the invention advantageously comprises more than 80% by mass, in particular between 90% and 100% by mass, of one or more lubricating oil(s) at least partly re-refined, relative to the total mass of the composition. In a particular embodiment, a composition used as a lubricating fluid according to the invention is completely free of base oil other than re-refined lubricating oils.

[0233] According to a preferred embodiment of the invention, the composition used as a lubricating fluid, and advantageously as a lubricating and cooling fluid, has a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, preferably 15 to 25 mm 2 / s, preferably still from 20.5 to 24 mm 2 / s, or even 21 to 24 mm 2 / s, typically measured according to ASTM D445.

[0234] The composition used as a lubricating fluid, and advantageously as a lubricating and cooling fluid, advantageously has at least one, at least two, or even all of the following characteristics:

[0235] - a kinematic viscosity measured at 100°C typically measured according to the ASTM D445 standard greater than or equal to 2 mm 2 / s, for example between 2 and 10 mm 2 / s, especially between 3 and 8 mm 2 / s ;

[0236] - a density at 15°C typically measured according to standard NF EN ISO 12185 less than or equal to 860 kg / m 3 , in particular between 830 and 860 kg / m 3 , particularly between 840 and 860 kg / m 3 ;

[0237] - a thermal conductivity, measured at 90°C and at atmospheric pressure, typically measured according to standard ASTM D7896-19, greater than or equal to 115 mW / mK, in particular between 115 and 140 mW / mK, in particular between 120 and 130 mW / mK.

[0238] According to a particular embodiment, the composition has:

[0239] - a kinematic viscosity typically measured according to ASTM D445 measured at 40°C ranging from 12 to 26 mm 2 / s, especially 15 to 25 mm 2 / s ; and

[0240] - a thermal conductivity, measured at 90°C and at atmospheric pressure, typically measured according to the ASTM D7896-19 standard, ranging from 115 to 140 mW / mK, in particular from 120 to 130 mW / mK. According to a preferred embodiment of the invention, the composition used as a lubricating fluid, and advantageously as a lubricating and cooling fluid, comprises:

[0241] - from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a first lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 5 to 20 mm 2 / s, preferably 10 to 16 mm 2 / s, typically measured according to ASTM D445; and

[0242] - from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a second lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 21 to 35 mm 2 / s, preferably 25 to 32 mm 2 / s, typically measured according to ASTM D445; relative to the total weight of the composition.

[0243] Preferably, according to this embodiment, the first lubricating oil, at least partly re-refined, has a kinematic viscosity at 40°C ranging from 5 to 20 mm 2 / s, preferably 10 to 16 mm 2 / s has one or more of the following characteristics:

[0244] - a kinematic viscosity at 100°C measured according to the ASTM D445 standard ranging from 2 to 6 mm 2 / s ; and / or

[0245] - a viscosity index measured according to standard NF ISO 2909 ranging from 105 to 120; and / or

[0246] - a flash point measured according to standard NF EN ISO 2592 ranging from 180°C to 210°C; and / or

[0247] - a sulfur content ranging from 0.01 to 0.05% by weight, relative to the total weight of the at least partly re-refined lubricating oil; and / or

[0248] - a Noack volatility measured according to the CEC L-40-93 standard at 250°C ranging from 15 to 40%.

[0249] Preferably, according to this embodiment using a mixture of two lubricating oils at least partly re-refined, the second lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 21 to 35 mm 2 / s, preferably 25 to 32 mm 2 / s, has one or more of the following characteristics:

[0250] - a kinematic viscosity at 100°C measured according to the ASTM D445 standard ranging from 4 to 10 mm 2 / s ; and / or

[0251] - a viscosity index measured according to standard NF ISO 2909 ranging from 110 to 130; and / or

[0252] - a flash point measured according to standard NF EN ISO 2592 ranging from 210°C to 240°C; and / or

[0253] - a sulfur content ranging from 0.02 to 0.2% by weight, relative to the total weight of the at least partly re-refined lubricating oil; and / or

[0254] - a Noack volatility measured according to the CEC L-40-93 standard at 250°C ranging from 8 to 11.9%.

[0255] In a particular embodiment, a composition used as a lubricating fluid according to the invention may comprise, in addition to said re-refined lubricating oil(s), one or more additives, in particular intended to promote the compatibility of the lubricating fluid with the materials of the system for which it is intended.

[0256] These additives may in particular be chosen from anti-corrosion additives, friction modifier additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, and mixtures thereof.

[0257] These additives may be added to the regenerated base oil(s) used according to the invention or to the mixture of the regenerated base oil(s) and at least one new base oil in an appropriate quantity, determined by a person skilled in the art. It is understood that the nature and quantity of the additives used are chosen in such a way that the advantageous properties, as a lubricating fluid, of the composition based on the re-refined lubricating oil(s), are not or are not substantially altered by the envisaged addition. A composition used as a lubricating fluid according to the invention may comprise between 0% and 20% by mass, in particular between 0.01% and 10% by mass, of additives, in particular as described above, relative to the total mass of the composition.

[0258] According to one embodiment, the invention thus relates to the use of a composition comprising at least one re-refined lubricating oil as a lubricating fluid for the lubrication of the components of a propulsion system of an electric or hybrid vehicle, the composition having a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than or equal to 115 mW / mK.

[0259] According to one embodiment, the invention thus relates to the use of a composition comprising at least one re-refined lubricating oil as a single lubricating fluid for the lubrication and cooling of all the components of a propulsion system of an electric vehicle, the composition having a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than 115 mW / mK, more particularly between 115 and 140 mW / mK.

[0260] The invention thus relates, according to another of its aspects, to a process or method for preparing a lubricating fluid, comprising at least one step consisting of obtaining a lubricating oil at least partly re-refined from a used lubricant.

[0261] Advantageously, such a process or method comprises at least the steps consisting of:

[0262] (i) having an at least partly re-refined lubricating oil obtained from a used lubricant, in particular formed by subjecting a used lubricant to at least one or more steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material, preferably as detailed previously;

[0263] (ii) optionally, mixing said at least partly re-refined lubricating oil with one or more new base oils, distinct from re-refined lubricating oils, for example one or more mineral oils; and (iii) optionally, supplementing said at least partly re-refined lubricating oil from step (i) or the mixture of lubricating oils from step (ii), with at least one additive, in particular as described above.

[0264] Applications

[0265] As mentioned above, an at least partially re-refined lubricating oil is suitable for use as a lubricating fluid, given its durability properties, particularly for the lubrication of components of a propulsion system of an electric or hybrid vehicle.

[0266] As mentioned above, the at least partly re-refined lubricating oil is also particularly suitable for use as a coolant, given its thermo-physical properties.

[0267] In particular, a fluid based on at least one re-refined lubricating oil according to the invention can be used for various systems and applications, in particular as a single fluid for the lubrication and cooling of the components of a propulsion system of an electric vehicle.

[0268] In particular, the present invention relates to the use of a composition based on at least one lubricating oil at least partly re-refined as a fluid for lubricating the components of a propulsion system of an electric vehicle.

[0269] Preferably, the composition based on at least one at least partially re-refined lubricating oil is used as a fluid for the lubrication and cooling of the components of a propulsion system of an electric vehicle.

[0270] More particularly, the composition based on at least one at least partially re-refined lubricating oil is used as the sole fluid for lubricating the geared motor and for cooling the battery of an electric vehicle.

[0271] The invention relates in particular to a method or process for lubricating, and preferably for lubricating and cooling, at least one component of a propulsion system of an electric or hybrid vehicle, preferably all of the components of a propulsion system of an electric vehicle, said method or process comprising at least one step of bringing into contact at said component, as lubricating fluid, advantageously lubricating and cooling fluid, a composition based on at least one at least partly re-refined lubricating oil, in particular as described above.

[0272] Such a process or such a method comprises in particular the steps consisting of: a) having a composition comprising, or even being formed from, one or more lubricating oil(s) at least partly re-refined, in particular as defined previously; b) implementing said composition of step a) at the level of a component of a propulsion system of an electric or hybrid vehicle, in particular as described previously; and c) circulating said composition to ensure lubrication and advantageously lubrication and cooling during the operation of said propulsion system of an electric or hybrid vehicle.

[0273] For the purposes of the present invention, the term "propulsion system" means a system comprising the mechanical parts necessary for the propulsion of a vehicle. The propulsion system more particularly includes a motor, for example an electric motor comprising the rotor-stator assembly of the power electronics (dedicated to speed regulation), a transmission and possibly a battery. The battery itself is generally made up of a set of electrical accumulators, called cells.

[0274] Also, a lubricating fluid based on at least one re-refined lubricating oil according to the invention can further be used as a cooling fluid to cool the battery present in an electric or hybrid vehicle.

[0275] As an example of application, a lubricating fluid according to the invention based on at least one re-refined lubricating oil can be used for the lubrication and cooling of a propulsion system of an electric or hybrid vehicle, and more particularly of the engine, the power electronics, the transmission and / or the battery.

[0276] A composition according to the invention based on at least one re-refined lubricating oil makes it possible to jointly achieve good properties in terms of cooling and lubrication of parts in a propulsion system of an electric or hybrid vehicle, such as an electric motor of an electric or hybrid vehicle, as well as in terms of cooling the battery of an electric or hybrid vehicle.

[0277] The present invention also relates, according to another of its aspects, to a propulsion system for an electric or hybrid vehicle, in which a composition based on at least one at least partly re-refined lubricating oil, in particular as defined in the invention, is used as a lubricating fluid, preferably as a lubricating and cooling fluid, more preferably as a single fluid for the lubrication and cooling of all the components of a propulsion system of an electric vehicle.

[0278] According to the invention, the particular, advantageous or preferred characteristics of these oils and compositions make it possible to define uses according to the invention which are also particular, advantageous or preferred.

[0279] The invention will now be described by means of the following examples, given by way of illustration and not limitation of the invention.

[0280] Example

[0281] Method for measuring kinematic viscosity

[0282] The kinematic viscosity of oils is measured at 40°C (KV40) and at 100°C (KV100) using a viscometer, according to standard NF EN ISO 3104. This standard is technically equivalent to standard ASTM D445. The results are expressed in mm 2 / s (equivalent to centistoke, noted cSt). Method of measuring volatility

[0283] Volatility is used to determine the evaporation loss of oils at high temperatures. It is determined by the NOACK volatility test, carried out according to CEC L-40-93. During the test, the oil sample is subjected to a constant air flow, heated to approximately 250°C, for approximately 60 minutes. The result is expressed as a fraction of weight loss, as a mass percentage.

[0284] Method of measuring density

[0285] The density of oils is measured at 15°C using a U-tube densimeter, according to standard NF EN ISO 12185. It is expressed in kg / m 3

[0286] Method of measuring viscosity index

[0287] The viscosity index is a dimensionless ratio that provides an indication of how the viscosity of oils varies with temperature. It is calculated from the kinematic viscosity values ​​at 40°C and 100°C, according to standard NF ISO 2909. The higher this index, the less the viscosity of oils is influenced by temperature variations.

[0288] Method of measuring thermal conductivity

[0289] Thermal conductivity, often denoted by Δ (lambda), characterizes the oil's ability to diffuse heat into the environment. It is measured by a transient hot-wire liquid thermal conductivity method, according to ASTM D7896-19. It is expressed in mW / mK.

[0290] Method of measuring heat capacity

[0291] The heat capacity (Cp) of a sample corresponds to the quantity of energy, in the form of heat, that must be added to it or lost to obtain a variation in its temperature of one degree. It was determined according to ASTM E1269 at different temperatures, from 0 to 90°C. It is expressed in J / (g*K). Flash point measurement method

[0292] The flash point provides an indication of a product's ability to form a flammable mixture with air under controlled conditions. It is determined using a Cleveland open-cup apparatus, according to standard NF EN ISO 2592. The flash point at ambient atmospheric pressure is the lowest temperature at which the passage of a flame over the test vessel containing the oil causes the vapors above the surface of the liquid to ignite. It is expressed in degrees Celsius.

[0293] Method for measuring sulfur and aromatic compound content

[0294] The sulfur and aromatic compound contents in the oil are determined by infrared or ultraviolet spectroscopy.

[0295] Measurement of gear deterioration by seizure

[0296] The galling load capacity indicates the maximum load that the lubricant can withstand without damaging the gear tooth surface. It is determined according to ISO 14635-1 (test method FZG A / 8.3 / 90).

[0297] Example 1

[0298] The properties of two re-refined lubricating oils 11 and 12, in accordance with the invention and commercially available, were evaluated.

[0299] These oils are obtained from used base oils and having undergone at least one step of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material, in particular at least one step of dehydration, distillation, liquid / liquid extraction and / or hydrogenation.

[0300] A new C1 lubricating oil, not in accordance with the invention because it had not undergone any recycling or re-refining step, was also evaluated.

[0301] This oil is a monoester base oil. In particular, the kinematic viscosities at 40°C and 100°C, viscosity index, density, volatility, flash point and thermal conductivity of these oils were measured according to the protocols detailed above.

[0302] The results are presented in Table 2 for re-refined and virgin oils. [Table 2] nd not determined

[0303] These oils 11, I2 and C1 are formulated. The formulated compositions are described in Table 3. In Table 3:

[0304] - ADD1 is an additive package comprising at least one phosphorus anti-wear agent and at least one anti-foam agent.

[0305] - ADD2 is an antioxidant.

[0306] - ADD3 is a pour point depressant.

[0307] - ADD4 is a viscosity agent polymer. [Table 3]

[0308] These compositions were evaluated for their mechanical durability properties, their physicochemical properties as well as their cooling properties. The results are shown in Table 4. [Table 4] Results

[0309] The results in Table 4 show that the composition according to the invention (FI1) comprising a mixture of two at least partly re-refined oils exhibits both good mechanical durability properties (seizure load capacity) and good cooling properties (thermal conductivity).

[0310] Consequently, the at least partially re-refined oils have particularly advantageous mechanical durability and thermo-physical properties, allowing access to performances as lubricating and cooling fluids identical or even superior to those of new lubricating oils, which have not undergone any recycling.

[0311] A lower density also helps ensure good hydraulic performance, in particular reducing the costs associated with pumping these oils during their use as a lubricating and cooling fluid. In conclusion, a lubricating oil that is at least partly re-refined has particularly advantageous properties, in particular identical or even superior to those of a new oil, allowing its use as a lubricating fluid and cooling fluid.

Claims

Claims 1. Use of a composition comprising at least one lubricating oil at least partly re-refined as a lubricating fluid for the lubrication of the components of a propulsion system of an electric or hybrid vehicle.

2. Use according to the preceding claim, in which the composition is used as a lubricating fluid for the geared motor and as a cooling fluid for the battery.

3. Use according to any one of the preceding claims, in which the composition is used as the sole fluid for the lubrication and cooling of all the components of a propulsion system of an electric vehicle.

4. Use according to any one of the preceding claims, wherein the composition makes it possible to improve the mechanical durability properties, preferably both the mechanical durability properties and the cooling properties.

5. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil comes from a used lubricant having been subjected to one or more prior steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material.

6. Use according to any one of the preceding claims, in which the composition has a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, preferably 15 to 25 mm 2 / s, preferably still from 20.5 to 24 mm 2 / s, or even 21 to 24 mm 2 / s.

7. Use according to any one of the preceding claims, in which the composition comprises: - from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a first lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 5 to 20 mm 2 / s, preferably 10 to 16 mm 2 / s ; and - from 10 to 90% by weight, preferably from 20 to 80% by weight, more preferably from 30 to 70% by weight, of a second lubricating oil at least partly re-refined having a kinematic viscosity at 40°C ranging from 21 to 35 mm 2 / s, preferably 25 to 32 mm 2 / s, relative to the total weight of the composition.

8. Use according to any one of the preceding claims, in which the composition has: - a kinematic viscosity measured at 40°C ranging from 12 to 26 mm 2 / s, especially 15 to 25 mm 2 / s ; and - a thermal conductivity, measured at 90°C and at atmospheric pressure, ranging from 115 to 140 mW / mK, in particular from 120 to 130 mW / mK.

9. Use according to any one of the preceding claims, in which the composition has an alkylphenol(s) content of between 5 and 3,200 ppm.

10. Use according to any one of the preceding claims, in which the composition has a sulfur content of between 0.001 and 0.2% by mass, preferably between 0.01% and 0.2% by mass, relative to the total mass of said at least partly re-refined lubricating oil.

11. Use according to any one of the preceding claims, in which the composition has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said at least partly re-refined lubricating oil.

12. Use according to any one of the preceding claims, in which the composition has a density less than or equal to 870 kg / m 3 , in particular between 830 and 870 kg / m 3 , more particularly between 840 and 860 kg / m 3 .

13. Use according to any one of the preceding claims, in which the composition has a thermal conductivity, measured at 90°C and at atmospheric pressure, greater than or equal to 115 mW / mK, more particularly between 115 and 140 mW / mK.

14. Use according to any one of the preceding claims, wherein said composition comprises one or more base oils distinct from the at least partly re-refined lubricating oil and / or one or more additives, in particular chosen from anti-corrosion additives, friction modifier additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, and mixtures thereof.

15. Use according to any one of the preceding claims, in which said composition comprises more than 80% by mass, in particular between 90% and 100% by mass of one or more lubricating oils at least partly re-refined, relative to the total mass of said composition.

16. Method for lubricating, preferably for lubricating and cooling, the components of a propulsion system of an electric vehicle, comprising at least one step of bringing into contact at the level of said system a composition based on at least one at least partly re-refined lubricating oil, in particular as defined in any one of claims 5 to 15.

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