Re-refined lubricating oils to improve the energy-saving properties of engine systems

Abstract

Title: Re-refined lubricating oils to improve the energy efficiency properties of powertrain systems. This application relates to the use of at least one lubricating oil, at least partially re-refined, to improve the energy efficiency properties of a lubricating composition intended for a powertrain system. It also relates to the use of a lubricating composition based on at least one lubricating oil, at least partially re-refined, to reduce the energy consumption of a powertrain system lubricated by said composition, particularly in a vehicle.

Description

Description Title of the invention: Re-refined lubricating oils to improve the energy-saving properties of engine systems Technical field

[0001] — The present invention relates to the field of lubricating compositions, more specifically- particularly the field of lubricating compositions used for lubri- Fiction of moving parts in stationary or motorization systems mobile, particularly in vehicles.

[0002] It relates more particularly to the use of re-refined lubricating oils in lubricating compositions intended for the lubrication of engine systems in order to improve their properties in terms of energy efficiency (“Energy ef- aptitude"), in other words, their ability to ultimately limit consumption energy of the motorization system. Previous technique

[0003] Lubricating compositions, also called "lubricants", are commonly implemented in the various components of motor vehicles for purposes main ways to reduce friction forces between different mechanical parts moving parts in these organs, in particular the engine, the transmission and the hydraulic circuit. They are also effective in preventing premature wear. or even damage to these parts, and in particular to their surface. To do this, A lubricating composition is classically composed of a base oil to which are generally associated with several additives dedicated to boosting performance. base oil modifiers, such as for example modifying additives friction, but also to provide additional performance.

[0004] — Internal combustion engines generate CO, in operation due to the combustion of the fuel they use to operate. Environmental concerns current measures, particularly those aimed at reducing carbon dioxide emissions, induce an urgent need to reduce the fuel consumption of motor vehicles.

[0005] As such, lubricants represent an effective means of acting on the fuel consumption via their impact on the friction forces generated between the various components of the engine systems, for example in vehicles with engine.

[0006] — Lubricants with good tensile or friction performance allow advantageously a reduction in friction in hy- lubrication regimes drodynamics and, consequently, a reduction in fuel consumption.

[0007] — Thus, the formulation of lubricants exhibiting good traction performance or friction represents an important issue as it constitutes an important lever in reducing fuel consumption, and therefore in reducing carbon dioxide emissions and, more generally, in reducing the energy consumption of engine systems. Summary of the invention The present invention aims precisely to propose new lubricating compositions for the lubrication of engine systems, in particular in vehicles, leading to improved performance in terms of energy economy, for example in terms of fuel economy. Surprisingly, as the following examples show, inventors have discovered that re-refined oils, from used oil recycling channels, provide access to lubricants with improved properties in terms of energy efficiency, in particular by reducing the coefficient of traction. Thus, the invention relates, according to a first of its aspects, to the use of at least one lubricating oil at least partly re-refined to improve the energy efficiency properties of a lubricating composition intended for a motorization system. In the context of the present invention, the expression "lubricating oil at least partly re-refined", also referred to more simply in the following text as "re-refined oil", "regenerated oil" or "recycled oil", designates an oil derived at least partly from a used lubricating composition that has been subjected to one or more treatment steps known as re-refining treatment. According to the invention, the term "used lubricating composition" (or more simply "used lubricant" or "used lubricating oil") means 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. Used lubricating oil can come from various sources. In particular, as detailed later in the text, it can be a lubricant that has been used to lubricate a motorization system, especially a "mobile" one, or to lubricate an industrial system, especially a "stationary" one. Due to their origin, used lubricating oils, particularly engine lubricating oils, contain a number of degradation products derived from the oil itself or its additives, as well as metal particles, metal oxides, and other elements, originating, for example, from the engine. Used oil may contain, in particular, high levels of undesirable elements, such as calcium (Ca), iron (Fe), magnesium (Mg), sodium (Na), and nickel. (Ni), phosphorus (P), silicon (Si), chlorine (Cl), zinc (Zn) etc. Methods for re-refining or reconditioning used lubricating oils have been developed, in order to regenerate these oils and allow their subsequent reuse. A re-refined lubricating oil is thus an oil obtained after one or more processing steps of a used lubricant, aimed at eliminating, at least in part, a number of contaminating elements present in it, such as dust, water, fuel fractions, metallic elements and other residues resulting from the degradation of additives present in the lubricant. Preferably, as detailed later in the text, the lubricating oils at least partially re-refined implemented according to the invention have characteristics, particularly in terms of saturated compound content, sulfur content and viscosity index, that satisfy the criteria defined by the API classification for Group I or Group IL oils. Lubricating oils at least partially re-refined implemented according to the invention preferably have a kinematic viscosity measured at 100°C according to ASTM D445 greater than or equal to 4.0 mm” / s, in particular between 4.0 and 12 mm” / s, in particular greater than or equal to 4.3 mm” / s and more particularly between 4.4 and 10 mm” / s, in particular between 4.5 and 6 mm? / s. To the inventors' knowledge, it has never been proposed to implement recycled lubricating oil in a lubricating composition intended for a motorization system, to improve its performance in terms of energy efficiency. Energy efficiency refers to the ability of a lubricant composition to ultimately limit the energy consumption of a mobile or stationary drive system, whether combustion, hybrid, or electric, particularly, but not exclusively, by reducing the coefficient of traction or friction, especially at the level of the engine itself, but also of transmission components such as the gearbox, gears, axles, and bearings. This energy efficiency translates into fuel savings for a combustion engine ("Fuel Economy" or FE) or an extended lifespan or longer charging interval for an electric motor. The invention further relates to a process or method for improving the energy efficiency, for example the Fuel-Eco properties, of a lubricant intended for an engine system, by implementing in the lubricant formulation one or more base oils at least partially re-refined. In one particular embodiment, the invention relates to the use of at least one lubricating oil, at least partially re-refined, in a lubricating composition intended for a drive system equipped with an internal combustion engine, for improve its Fuel-Eco properties. As detailed later in the text, re-refined lubricating oils can thus be used to improve the "Energy Efficiency" properties of lubricants for various powertrain systems, including vehicles, including light vehicles, with combustion engines, electric or hybrid; heavy goods vehicles, or even marine vehicles. Preferably, the said re-refined lubricating oil(s) may represent more than 50% by mass, in particular more than 70% by mass, especially more than 80% by mass and more particularly more than 90% by mass, of the total mass of the lubricating composition. As detailed later in the text, the re-refined lubricating oil(s) can be used as the sole base oil(s), that is, without the addition of a separate base oil, such as new base oil. Alternatively, they can be used in combination with at least one new base oil. In a particular embodiment, the lubricating composition consists solely of one or more re-refined lubricating oils. Advantageously, the use of one or more re-refined lubricating oils makes it possible to improve the energy efficiency of lubricating compositions by reducing their coefficient of traction. Thus, the said lubricating oil(s), at least partially re-refined, are notably used according to the invention to reduce the coefficient of traction of the lubricating composition. This coefficient of traction, denoted COT, can be measured using an MTM tribometer, for example under the conditions detailed in the examples. Surprisingly, as illustrated in the examples, the inventors discovered that recycled oils have lower coefficients of traction compared to new oils, making them particularly advantageous for improving the energy efficiency of lubricants. Indeed, a lower coefficient of traction effectively reduces friction losses in mechanical contacts, thus lowering engine energy consumption, such as the fuel consumption of an internal combustion engine. Advantageously, re-refined oils allow a reduction in the coefficient of traction over a wide temperature range, corresponding to the temperatures encountered at the engine level, in particular for temperatures ranging from 40°C to 100°C. The invention further relates to the use of a lubricating oil at least partly re-refined to reduce the coefficient of traction of a lubricating composition intended for the lubrication of a motorization system. It also relates to a process or method for reducing the coefficient of traction of a lubricant intended for the lubrication of an engine system, by implementing in the lubricant formulation one or more base oils at least partially re-refined. The invention further relates, according to another of its aspects, to the use of a lubricating composition based on at least one lubricating oil at least partly re-refined, to reduce energy consumption or improve the energy saving properties of a motorization system lubricated by means of said lubricating composition, for example fuel consumption in the context of a combustion motorization system. As detailed later in the text, the said motorization system may be in particular a mobile or stationary motorization system, combustion, electric or hybrid, in particular in a vehicle, in particular in a light vehicle, heavy vehicle or marine vehicle. The invention further relates to a process or method for reducing energy consumption or for improving the energy saving properties of a motorization system, in particular in a vehicle, comprising the lubrication of at least one of the parts of the motorization system with a lubricating composition comprising at least one oil that is at least partially re-refined. The process or method for reducing the energy consumption of a motorization system may, in particular, include the following steps: (i) prepare a lubricating oil at least partly re-refined from a used lubricant; (ii) optionally, mix said lubricating oil at least partly re-refined with one or more new base oil(s), separate from re-refined lubricating oils, for example one or more mineral oils; (iii) supplement said lubricating oil, at least partially re-refined from step (i), or the lubricating oil blend from step (ii), with one or more additives, for example as described later in the text; and (iv) use the lubricant obtained at the end of step (iii) for the lubrication of at least one mechanical part of said engine system Also, advantageously, as illustrated in the examples that follow, regenerated lubricating oils exhibit reduced Noack volatility compared to that of a virgin base oil. Thus, the said lubricating oil(s), at least partially re-refined, are notably used according to the invention to reduce the Noack volatility of the lubricating composition. Noack volatility can notably be determined according to the CEC L-40-93 standard. Lower volatility makes it advantageous to consider the use of more fluid base oils in lubricant formulations, which also allows for improvements in the energy efficiency of the composition, for example, in the case of a composition intended for a combustion engine system, to maximize Fuel-Eco gains. The invention further relates to the use of a lubricating oil at least partly re-refined to reduce the volatility of a lubricating composition intended for the lubrication of a motorization system. It also relates to a process or method for reducing the volatility of a lubricant intended for the lubrication of an engine system, by implementing in the lubricant formulation one or more base oils at least partially re-refined. Advantageously, the use of re-refined lubricating oils according to the invention thus makes it possible to meet current expectations for reducing environmental impact and conserving resources through two levers: on the one hand, the formulation of lubricants based on regenerated lubricating oils makes it possible to reduce the carbon footprint of the products, compared to the use of virgin base oils and, on the other hand, as described above, the use of re-refined base oils makes it possible to improve the energy efficiency of lubricating compositions, in particular by reducing the coefficient of traction, and in particular to act on reducing the fuel consumption of combustion engine systems and therefore on CO emissions, Other features, variations and advantages of implementing lubricating oils at least partially re-refined according to the invention will become clearer from reading the description and examples that follow, given by way of illustration and not limitation of the invention. In the following text, the expressions "between … and …", "ranging … to .…." and "varying from … to ..." are equivalent and are meant to mean that the limits are included, unless otherwise stated. In the description and examples, unless otherwise stated, percentages are mass percentages. Therefore, percentages are expressed as a percentage of the total mass of the composition. Detailed description Lubricating oil, at least partially re-refined As previously mentioned, the base oil used to improve the energy efficiency properties of lubricating compositions is a lubricating oil that is at least partially re-refined, also known as "regenerated oil" or "recycled oil", in other words, a lubricating oil derived from a used lubricating composition that has undergone one or more re-refining treatment stages. 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. Used lubricating compositions, and consequently regenerated lubricating oils, comprise, in 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 mixtures thereof. This may be a mixture of several base oils, for example, a mixture of two, three, or four base oils. These base oils can be of natural origin, for example from plants or animals, such as vegetable oils, animal oils, 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. 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. [Table 1] Viscosity index | Saturated fat content | Sulfur content | (VD <90% > 0.03% 80 <VI< 120 Group I <90% >0.03% 80 <vi<1 huiles minérales groupement ii ; 290 %="z120" <0,03 80 <vi< | hydrocraquées iii 290% ou hydro-isomérisées Group IV Polyalphaolefins (PAO) Group V Esters and other bases not included in groups I to IV | In particular, the used lubricating composition, from which the regenerated lubricating oil implemented 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). According to a particular embodiment, the re-refined lubricating oil implemented according to the invention can be obtained from the treatment of a used lubricating composition that has been used for the lubrication of a motorization system, in particular "mobile", i.e. including light vehicles, heavy goods vehicles, mobile machines known as "off road", or even marine vehicles. According to another particular embodiment, the re-refined lubricating oil implemented according to the invention can be obtained from the treatment of a used lubricating composition that has been used for the lubrication of an industrial system, in particular a "stationary" one, i.e. including, but not limited to, turbines, compressors, hydraulic systems, gears, or even forming or cutting machines. A used lubricating composition, from which the regenerated lubricating oil used according to the invention is derived, may contain various conventional additives in the field of lubricants, such as friction modifiers, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD) additives, dispersants, anti-foaming agents, thickeners, and mixtures thereof. As previously mentioned, the properties of the used lubricant 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. Due to their origin, used lubricating compositions may contain one or more of the 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. The composition of used lubricant can of course be different depending on the origin of the lubricant, its initial formulation and the fact that it may have been contaminated differently depending on its use. The regenerated lubricating oil implemented according to the invention comes more particularly from a used lubricant which has been subjected to one or more prior pre-treatment steps known in the field of re-refining used lubricants. In particular, these treatment steps aim to eliminate, at least partially, water, solid particles, fuel and / or other contaminants, such as polycyclic aromatic hydrocarbons (PAHs), which are undesirable in lubricant formulations. According to a particular embodiment, the regenerated lubricating oil implemented according to the invention comes from a used lubricant that has been subjected to one or more prior steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passing of the used lubricant over an adsorbent material, preferably as detailed below. Preferably, the regenerated lubricating oil produced according to the invention is obtained by subjecting a used lubricating composition to at least one dehydration step. This dehydration step removes any water that may be present in the used lubricant. Advantageously, the regenerated lubricating oil implemented according to the invention thus comprises a water content 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 a person skilled in the art, for example by distillation, evaporation, decantation, heating or passing a stream of hot air over the used lubricating composition. 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. Preferably, the regenerated lubricating oil produced according to the invention is obtained by subjecting a used lubricating composition to at least one preliminary filtration step. This filtration can be carried out by any method known to those skilled in the art. This filtration step may be a particulate or non-particulate filtration step. For example, it can be carried out using diatomaceous earth systems. Preferably, the regenerated lubricating oil produced according to the invention is obtained by subjecting a used lubricating composition to at least one distillation step, preferably following a prior dehydration step. This distillation step(s) can be carried out using any technique known to those skilled in the art. For example, it could be atmospheric distillation or distillation under reduced pressure. The distillations can, for example, be carried out at a temperature between 100 °C and 500 °C, preferably between 200 °C and 400 °C, and more preferably between 300 °C and 380 °C. In particular, They can be operated at a pressure between 25 and 2,000 Pa, preferably between 50 and 1,000 Pa, more particularly between 50 and 250 Pa. Advantageously, the regenerated lubricating oil implemented 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 allows for the selective adsorption of aromatic compounds, particularly PAHs. In particular, passing over an adsorbent material, preferably activated carbon, advantageously reduces the content of polycyclic aromatic hydrocarbons (PAHs), notably those selected from chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, dibenz[a,h]Janthracene and / or benz[a]Janthracene, of the used lubricating composition. The term "passage of the used lubricating composition over an adsorbent material" refers to the flow of the used lubricating composition over the adsorbent support. Examples of adsorbent materials include activated carbon, zeolites, clays, and functionalized porous compounds. Activated carbon is preferred. For example, the regenerated lubricating oil used in the process of the invention can be obtained from the treatment of a used lubricating composition according to the process described in document WO 2018 / 109208. 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 litre 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. The flow rate of the used lubricant composition can be between 1 m°* / het 15 mŸh, for example between 5 and 10 m° / h. Preferably, activated carbon is characterized by a density between 200 and 500 kg / m°, for example measured according to the ASTDM D2854 standard. Preferably, activated carbon is coal-based carbon, preferably comprising 70 to 95%, advantageously 80 to 90% by weight of carbon. The step of passing the used lubricating composition over an adsorbent support, preferably activated carbon, is advantageously preceded by the following preliminary steps: - one or more distillation stages; and - a filtration step, in particular as defined previously. Advantageously, the regenerated lubricating oil produced according to the invention can be obtained by subjecting a used lubricating composition to at least one preliminary hydrogenation (or hydrotreating) step, preferably following a preliminary dehydration and / or distillation step. This 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, usually in the presence of a hydrotreating catalyst. Such a catalyst may contain, for example, at least one oxide or sulfide of at least one Group VI metal and / or at least one Group VIIL metal, such as molybdenum, tungsten, nickel, or cobalt, and a carrier, for example, alumina, silica-alumina, or a zeolite. Advantageously, the regenerated lubricating oil produced according to the invention can be obtained by subjecting a used lubricating composition to at least one preliminary liquid / liquid extraction step with a solvent, preferably following a preliminary dehydration and / or distillation step. In particular, liquid / liquid extraction with a solvent advantageously clarifies dark-colored used oil and at least partially removes unpleasant odors or aromatic compounds, especially PAHs. This extraction step(s) can be carried out using any technique known to those skilled in the art. The extraction is generally performed in a mixer-settler or in an extraction column, using a suitable extraction solvent. Advantageously, the regenerated lubricating oil implemented according to the invention can be obtained by subjecting a used lubricating composition to at least one preliminary settling step. This settling step(s) can be carried out using 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 lubricating oils, at least partially re-refined, obtained from treatment steps other than those described above, may be suitable for the invention. In any event, a re-refined lubricating oil implemented according to the invention differs from a used lubricating oil, in particular due to the reduced content of certain undesirable contaminants, for example water, fuel, metallic elements or certain heteroatoms. On the other hand, a regenerated lubricating oil implemented according to the invention differs, due to its formation from a used lubricant, from a virgin or new base oil, oil directly from petroleum refining, or even from native base oils, for example of natural origin, both in terms of its composition and of its physico-chemical properties. A regenerated lubricating oil implemented according to the invention is in particular characterized by a silicon content between 0 ppm and 300 ppm, in particular between 1 and 300 ppm. A regenerated lubricating oil implemented according to the invention is in particular characterized by a phosphorus content less than or equal to 100 ppm, in particular between 0 ppm and 100 ppm, for example 0 ppm. A regenerated lubricating oil implemented according to the invention can also be characterized by its content of one or more other elements selected from chlorine, oxygen, and nitrogen. For example, it may have a chlorine content between 0 ppm and 50 ppm, for example, 0 ppm. The content of these elements can be evaluated by any method known to those skilled in the art, for example by X-ray fluorescence (XRF), or by infrared or ultraviolet spectroscopy. Preferably, the re-refined lubricating oils implemented according to the invention have characteristics, particularly in terms of saturated compound content, sulfur content and viscosity index, that satisfy 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. According to a particularly preferred embodiment, the re-refined lubricating oil(s) used according to the invention are chosen from among the re-refined oils whose characteristics, in particular in terms of saturated compound content, sulfur content and viscosity index, satisfy the criteria defined by the API classification for Group I or Group II oils. Preferably, the re-refined lubricating oils implemented according to the invention, in particular whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, have a kinematic viscosity measured at 100°C according to ASTM D445, between 4.0 and 12 mms", Advantageously, the re-refined lubricating oil implemented according to the invention has a kinematic viscosity measured at 100°C according to ASTM D445, greater than or equal to 4.3 mm°.s⁻¹, in particular between 4.4 and 10 mm°.s⁻¹ and more particularly between 4.5 and 6 mm°.s⁻¹, Preferably, a re-refined lubricating oil implemented according to the invention, in particular one whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, has a viscosity index greater than or equal to 110. The viscosity index of the lubricating oil, at least partially re-refined, may more particularly be between 110 and 130, in particular particularly between 112 and 125 and more particularly between 112 and 122. The viscosity index can in particular be determined according to the NF ISO 2909 standard. Preferably, a regenerated lubricating oil implemented according to the invention, in particular whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, has a sulfur content of between 0.01% and 0.2% by mass, relative to the total mass of said regenerated lubricating oil. Preferably, a regenerated lubricating oil implemented according to the invention, in particular having characteristics equivalent to those defined by the API classification for Group I or Group II base oils, has an aromatic compound content 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 aromatic compound content in the regenerated lubricating oil may, in particular, 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. The levels of these different elements can be determined by any method known to a person skilled in the art, for example by X-ray fluorescence (XRF) or by Infrared or Ultraviolet spectroscopy. In a first embodiment, the re-refined lubricating oil implemented according to the invention has characteristics, particularly in terms of saturated compound content, sulfur content and viscosity index, that satisfy the criteria defined by the API classification for Group I oils. Such a regenerated oil, whose characteristics are equivalent to those of Group I base oils, advantageously exhibits a kinematic viscosity measured at 100°C according to ASTM D445, greater than or equal to 4.4 mm² / s, in particular between 4.5 and 10 mm² / s and more particularly between 4.5 and 6 mm² / s. In particular, it has a viscosity index greater than or equal to 110, especially between 110 and 130, particularly between 112 and 125 and more particularly between 112 and 122. The viscosity index can in particular be determined according to the NF ISO 2909 standard. Preferably, a regenerated lubricating oil implemented according to the invention has a sulfur content greater than 0.03% by mass, in particular between 0.05 and 0.20% by mass. Preferably, a regenerated lubricating oil implemented according to the invention has an aromatic compound(s) content greater than or equal to 5% by mass, in particular between 5% and 15%, especially between 7% and 20%, relative to the total mass of said regenerated lubricating oil. In another particular embodiment, the re-refined lubricating oil implemented according to the invention has characteristics, particularly in terms of saturated compound content, sulfur content and viscosity index, that satisfy the criteria defined by the API classification for Group II oils. Such a regenerated oil, whose characteristics are equivalent to those of Group II base oils, advantageously exhibits a kinematic viscosity measured at 100°C according to ASTM D445, greater than or equal to 4.0 mm? / s, in particular between 4.2 and 10 mm?° / s, more particularly between 4.3 and 6 mm? / s. In particular, it has a viscosity index greater than or equal to 110, in particular between 110 and 130, especially between 112 and 125 and more particularly between 115 and 120. The viscosity index can in particular be determined according to the NF ISO 2909 standard. Preferably, a regenerated lubricating oil implemented according to the invention has a sulfur content less than or equal to 0.03% by mass, in particular less than or equal to 0.02% by mass. Preferably, a regenerated lubricating oil implemented according to the invention has an aromatic compound(s) content of less than or equal to 10% by mass, in particular less than or equal to 9% by mass, and more particularly between 1 and 9% by mass, relative to the total mass of said regenerated lubricating oil. As previously stated, the re-refined lubricating oils implemented according to the invention, in particular those whose characteristics are equivalent to those defined by the API classification for Group I or Group IT base oils, advantageously exhibit, compared to virgin base oils of equivalent group according to the API classification, reduced volatility. Volatility properties can be more specifically evaluated by determining Noack volatility according to CEC standard L-40-93. Advantageously, a regenerated lubricating oil implemented according to the invention has a Noack volatility of less than or equal to 15%, in particular less than or equal to 14%. More preferably, a regenerated lubricating oil implemented according to the invention can have a Noack volatility strictly less than 12%, in particular between 7% and 11%. Also, as mentioned previously, the re-refined base oils implemented according to the invention advantageously exhibit lower traction coefficients compared to virgin base oils, and this advantageously over a wide temperature range. The coefficient of traction can be determined by the MTM (Mini Traction) machine. Machine) sold by PCS instrument. It can be evaluated, as described in the examples, under the following operating conditions: temperature of 40°C or 100°C, load of 25N, sliding-rolling ratio (SRR) of 40%, and speed gradient from 2500 to 20 mmy / s. In particular, the coefficient of traction of a re-refined base oil, whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, is thus significantly reduced compared to the coefficient of traction of a virgin base oil of equivalent group according to the API classification. Advantageously, the coefficient of traction (COT) of the re-refined lubricating oils implemented according to the invention, in particular whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, is lowered by at least 7%, in particular by at least 10%, advantageously by at least 15%, in particular by at least 20%, or even by at least 25%, compared to the coefficient of traction of a virgin base oil of equivalent group according to the API classification. In particular, a re-refined base oil implemented according to the invention, whose characteristics are equivalent to those defined by the API classification for Group I base oils, advantageously exhibits a lower coefficient of traction than that of a Group I virgin base oil. Advantageously, the coefficient of traction TOC of a re-refined oil, whose characteristics are equivalent to those defined by the API classification for Group I base oils, evaluated at a temperature of 40°C, is less than or equal to 0.050, preferably less than or equal to 0.048 and more preferably less than or equal to 0.045. Advantageously, the coefficient of traction TOC of a re-refined oil, whose characteristics are equivalent to those defined by the API classification for Group I base oils, evaluated at a temperature of 100°C, is less than or equal to 0.026, preferably less than or equal to 0.025 and more preferably less than or equal to 0.024. Similarly, a re-refined base oil whose characteristics are equivalent to those defined by the API classification for Group II base oils advantageously presents a lower coefficient of traction than that of a Group II virgin base oil. Advantageously, the coefficient of traction TOC of a re-refined oil, whose characteristics are equivalent to those defined by the API classification for IT group base oils, evaluated at a temperature of 40°C, is less than or equal to 0.045, preferably less than or equal to 0.043. Advantageously, the coefficient of traction TOC of a re-refined oil, whose characteristics are equivalent to those defined by the API classification for Group II base oils, evaluated at a temperature of 100°C, is less than or equal to 0.022, preferably less than or equal to 0.020. Advantageously, these good traction coefficient reduction properties are verified over a wide range of lubricant operating temperatures, in particular for temperatures ranging from 40°C to 100°C, representative of the temperatures at the engine system level. According to a particular embodiment, a regenerated lubricating oil implemented according to the invention has a density less than or equal to 870 kg / m³, in particular less than or equal to 860 kg / m³. The density of the lubricating oil, at least partially re-refined, can thus be between 830 and 870 kg / m³, in particular between 840 and 860 kg / m³. Density can in particular be determined according to the standard NF EN ISO 12185. In particular, a regenerated lubricating oil implemented according to the invention has a flash point greater than or equal to 225 °C, in particular greater than or equal to 228 °C. The flash point of the lubricating oil, at least partially re-refined, can thus be between 225 °C and 245 °C. The flash point can be determined in particular according to standard NF EN ISO 2592. Specifically, a remanufactured lubricating oil used according to the invention has a thermal conductivity, measured at 100 °C and atmospheric pressure, greater than or equal to 125 mW / mK, and in particular greater than or equal to 128 mW / mK. The thermal conductivity of the lubricating oil, at least partially re-refined, can thus be between 125 and 145 mW / mK, and in particular between 128 and 140 mW / mK. The thermal conductivity can notably be determined according to standard ASTM D7896-19. LUBRICANT COMPOSITION The said re-refined lubricating oil(s) may be used as the sole base oil(s) of the lubricating composition, or may be formulated in combination with one or more separate base oils, in particular one or more new base oils. These new base oils in particular are chosen from among the base oils conventionally used in the field of lubricants, such as mineral, synthetic or natural, animal or vegetable oils or mixtures thereof. 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 mixtures thereof. A lubricating composition implemented according to the invention can thus comprise a mixture of one or more lubricating oils at least partly re-refined and one or more new base oils, for example at least one mineral oil. Preferably, a lubricating composition according to the invention comprises less than 50% by mass of new base oil(s), separate from re-refined lubricating oils. Preferably, a lubricating composition according to the invention is formed predominantly of said re-refined lubricating oil(s). In particular, the said re-refined lubricating oil(s) may represent more than 70% by mass of the total mass of the lubricating composition, in particular more than 80% by mass, in particular more than 90% by mass and more particularly between 95% and 100% by mass, in particular between 95% and 99% by mass, of the total mass of the lubricating composition. In a particular embodiment, a lubricating composition according to the invention is totally devoid of base oil distinct from re-refined lubricating oils. In a particular embodiment, a lubricating composition according to the invention is formed solely from one or more re-refined lubricating oils. In other words, the re-refined lubricating oil(s) may represent 100% of the lubricating composition. Additives A lubricating composition implemented according to the invention may further include all types of additives suitable for the intended use of the lubricant, as detailed in the following text, for example for use in motorization systems of light or heavy vehicles, or marine vehicles, in combustion, electric or hybrid motorization systems. These additives can be chosen from among friction modifiers, anti-wear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD) additives, dispersants, anti-foaming agents, thickeners, corrosion inhibitors, copper passivating agents, and mixtures thereof. Advantageously, a lubricating composition according to the invention comprises one or more additives selected from viscosity index improvers, pour point lowering additives, anti-wear additives, antioxidants and mixtures thereof. These additives can be added to the regenerated base oil(s) used according to the invention or to the mixture of the re- base oil(s). generated 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 "Energy efficiency" properties of the composition based on the said re-refined lubricating oil(s) are not, or are not substantially, altered by the envisaged addition. A lubricating composition implemented according to the invention may comprise between 0.01 and 20% by mass, in particular between 0.05 and 10% by mass of additives, in particular as described below, relative to the total weight of the composition. Advantageously, a lubricating composition implemented according to the invention may include at least one friction-modifying additive. Friction-modifying additives reduce friction by forming adsorbed monolayers on the surfaces of the metals in contact. They may be selected from compounds containing metallic elements and from ash-free compounds. Examples of compounds containing metallic elements include transition metal complexes such as Mo, Sb, Sn, Fe, Cu, and Zn, whose ligands may be hydrocarbon compounds containing oxygen, nitrogen, sulfur, or phosphorus atoms.Ash-free friction-modifying additives are generally of organic origin and can be selected from fatty acid and polyol esters, other than the monoester required according to the invention, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borate fatty epoxides, fatty amines, or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group comprising 10 to 24 carbon atoms. In particular, molybdenum-based compounds can be selected from molybdenum dithiocarbamates (Mo-DTC), molybdenum dithiophosphates (Mo-DTP), and mixtures thereof. Advantageously, a lubricating composition according to the invention may comprise from 0.01 to 5% by mass, preferably from 0.01 to 5% by mass, more particularly from 0.1 to 2% by mass or even more particularly from 0.1 to 1.5% by mass, relative to the total weight of the lubricating composition, of friction-modifying additives. Preferably, a lubricating composition according to the invention comprises at least one anti-wear additive, one extreme-pressure additive, or mixtures thereof. Anti-wear and extreme-pressure additives are designed to protect friction surfaces by forming a protective film adsorbed onto them. A wide variety of anti-wear additives exist. Particularly suitable for lubricating compositions according to the invention are anti-wear additives selected from polysulfide additives, sulfur olefin additives, or phospho-sulfur additives such as metallic alkylthiophosphates, especially alkylthiophosphates of zinc, and more specifically zinc dialkyldithiophosphates or ZnDTP. The preferred compounds have the formula Zn((SP(S)(OR)(OR”)}, in which R and R°, identical or different, independently represent an alkyl group, preferentially comprising from 1 to 18 carbon atoms. Advantageously, a lubricating composition according to the invention may comprise from 0.01 to 6% by mass, preferably from 0.05 to 4% by mass, more preferably from 0.1 to 2% by mass, relative to the total weight of the composition, of anti-wear additives and extreme pressure additives. Advantageously, a lubricating composition according to the invention may include at least one antioxidant additive. The antioxidant additive delays the degradation of the lubricating composition during service. This degradation can manifest itself in particular through the formation of deposits, the presence of sludge, or an increase in the viscosity of the lubricating composition. The additives act, in particular, as radical inhibitors or hydroperoxide scavengers. Commonly used antioxidant additives include phenolic antioxidants, amine antioxidants, and phosphosulfur antioxidants. Some of these antioxidants, such as phosphosulfur antioxidants, can generate ash. Phenolic antioxidants may be ash-free or in the form of neutral or basic metal salts. Antioxidant additives may include sterically hindered phenols, sterically hindered phenol esters, sterically hindered phenols containing a thioether bridge, diphenylamines, diphenylamines substituted with at least one C,-C, alkyl group, N,N'-dialkylaryl diamines, and mixtures thereof. Preferably, sterically hindered phenols are selected from compounds comprising a phenol group in which at least one vicinal carbon of the carbon bearing the alcohol functional group is substituted by at least one C10-C10 alkyl group, preferably a C4-C10 alkyl group, preferably a C1-C10 alkyl group, and preferably by the tert-butyl group. Amino compounds are another class of antioxidant additives that can be used, possibly in combination with phenolic antioxidant additives.Examples of amine compounds are aromatic amines, for example aromatic amines of formula NR°RSR7 in which R° represents an aliphatic or aromatic group, possibly substituted, RS represents an aromatic group, possibly substituted, R” represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R8S(O),R° in which RS represents an alkylene or alkenylene group, R° represents an alkyl, alkenyl or aryl group and z represents O, 1 or 2. Des. Alkyl phenols sulfurized or their alkali and alkaline earth metal salts can also be used as antioxidant additives. Advantageously, a lubricating composition according to the invention may comprise from 0.1 to 2% by mass, relative to the total weight of the composition, of at least one antioxidant additive. A lubricating composition according to the invention may also include at least one detergent additive. Detergent additives generally reduce the formation of deposits on the surface of metal parts by dissolving oxidation and combustion byproducts. Detergent additives usable in a lubricating composition according to the invention are generally known to those skilled in the art. Detergent additives may be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head group. The associated cation may be a metallic cation of an alkali or alkaline earth metal. Detergent additives are preferably selected from alkali or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, and phenate salts. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium, or barium.These metallic salts generally include the metal in stoichiometric quantities or in excess, i.e., in a quantity greater than the stoichiometric quantity. These are then called over-basic detergent additives; the excess metal giving the over-basic character to the detergent additive is then generally in the form of a metallic salt insoluble in the base oil, for example a carbonate, a hydroxide, an oxalate, an acetate, a glutamate, preferably a carbonate. A lubricating composition according to the invention may comprise from 0.5 to 8%, preferably from 0.5 to 4% by mass, relative to the total weight of the lubricating composition, of detergent additive. Advantageously, a lubricating composition according to the invention may also include at least one pour point depressant (PPD) additive. By slowing the formation of paraffin crystals, pour point depressant additives generally improve the cold-weather performance of the lubricating composition according to the invention. Examples of pour point depressants include alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, and alkylated polystyrenes. A lubricating composition according to the invention may comprise from 0.1% to 2%, preferably from 0.2% to 1% by mass of pour point lowering additive(s), relative to the total weight of the composition. A lubricating composition according to the invention may also comprise at least A dispersing agent. Such dispersing agents ensure the suspension and removal of insoluble solid contaminants consisting of secondary oxidation products that form when the lubricating composition is in service. They can be selected from Mannich bases, succinimides and their derivatives, such as polyisobutylene succinic anhydride derivatives. In particular, a lubricating composition according to the invention may comprise from 0.2 to 10% mass of dispersing agent(s), relative to the total weight of the composition. A lubricating composition according to the invention may also include at least one viscosity index improver (VI). Viscosity index improvers, particularly viscosity index improving polymers, ensure good cold-weather performance and minimal viscosity at high temperatures. Examples of viscosity index improving polymers include polymer esters, hydrogenated or non-hydrogenated homopolymers or copolymers of styrene, butadiene, and isoprene, olefin homopolymers or copolymers such as ethylene or propylene, and polyacrylates and polymethacrylates (PMAs), preferably olefin homopolymers or copolymers such as ethylene or propylene. In particular, a lubricating composition according to the invention may comprise from | to 15% by mass of additive(s) improving the viscosity index, preferably from 5% to 10% by mass, relative to the total weight of the lubricating composition. A lubricating composition may also include at least one antifoaming additive, for example, selected from polar polymers such as polymethylsiloxanes or polyacrylates. In particular, a lubricating composition according to the invention may include from 0.01 to 3% by mass of antifoaming additive(s), relative to the total weight of the lubricating composition. It may also include at least one anti-corrosion agent or copper passivating agent, for example compounds such as polyisobutenes succinic anhydrides, thiadiazole sulfonates, or mercaptobenzothiazoles. These are typically present in a lubricating composition according to the invention at concentrations between 0.01% and 1% by mass, relative to the total weight of the composition. Thus, a lubricating composition according to the invention may further comprise one or more base oils distinct from the lubricating oil, at least partially re-refined eV, and / or one or more additives, in particular selected from friction modifiers, anti-wear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD) additives, dispersants, antifoaming agents, thickeners, corrosion inhibitors, copper passivating agents, and mixtures thereof. APPLICATIONS As previously stated, re-refined oils, preferably whose characteristics are equivalent to those defined by the API classification for Group I or Group II base oils, are implemented according to the invention to improve the energy efficiency of lubricants intended for the lubrication of various engine systems. These can be mobile or stationary motorization systems. For the purposes of this invention, "motorization system" means a system comprising all the mechanical parts necessary for the intended mobile or stationary application and including, by means of it, a motor. This may be a combustion, gas (particularly hydrogen), ammonia, electric, or hybrid motorization system, depending on the nature of the motor(s) included in the motorization system: combustion, gas (particularly hydrogen), ammonia, and / or electric. A "stationary" drive system, as defined in the invention, is a drive system including a stationary engine. It can find applications, for example, in electrical power generation devices. In particular, it may be a gas-powered drive system, especially a stationary gas engine. A "mobile" motorization system is more specifically a motorization system implemented in vehicles, including light vehicles, heavy goods vehicles, so-called "off-road" mobile machines, or even marine vehicles. A mobile motorization system can thus be a propulsion system for a vehicle, in particular for a vehicle with an internal combustion engine, an electric vehicle or a hybrid vehicle. For the purposes of this invention, "propulsion system" means a system comprising the mechanical parts necessary for the propulsion of a vehicle. More specifically, the propulsion system includes an engine, for example an internal combustion engine or an electric motor comprising the rotor-stator assembly, power electronics, a transmission, and possibly a battery. As previously mentioned, the use of re-refined oils makes it advantageous to act effectively on the engine's energy consumption through its impact on the friction forces generated between the different components of the engine system, for example, the vehicle's propulsion system. A lubricating composition can thus be used for the lubrication of gears, transmission components, particularly at the level of the reducer, gearbox and / or axles, of the engine. In particular, the re-refined oils according to the invention can be used to reduce friction in the propulsion systems of light vehicles or heavy vehicles, in particular those with internal combustion engines, electric or hybrid engines. The invention will now be described by means of the following examples, given by way of illustration and not limitation of the invention. Examples Method for measuring kinematic viscosity The kinematic viscosity of oils is measured at 100°C (KV100) using a viscometer, according to standard NF EN ISO 3104. This standard is technically equivalent to ASTM D445. The results are expressed in mm” / s (equivalent to centistoke, denoted cSt). Method for measuring the viscosity index The viscosity index is a dimensionless ratio that indicates how the viscosity of oils varies with temperature. It is calculated from the kinematic viscosity values ​​at 40°C and 100°C, according to the NF ISO 2909 standard. The higher the index, the less the oil's viscosity is affected by temperature variations. Method for measuring the content of sulfur and aromatic compounds The sulfur and aromatic compound content in the oil is determined by infrared or ultraviolet spectroscopy. Volatility measurement method Volatility is used to determine the evaporation loss of oils at high temperatures. It is determined by the NOACK volatility test, performed according to CEC L-40-93. During the test, the oil sample is subjected to a constant airflow, heated to approximately 250 °C, for about 60 minutes. The result is expressed as a fraction of weight loss, as a mass percentage. Evaluation of the tensile coefficient of the compositions The coefficient of traction (COT) was measured using the PCS instrument MTM tribometer. It allows for the evaluation of lubricant performance in terms of friction under mixed / hydrodynamic conditions. This test involves the relative motion of a steel ball and a steel plate at different speeds, allowing the determination of the %SSR (Slide-to-Roll Ratio), which corresponds to the sliding speed / drive speed ratio. The measurement conditions were 25 N (920 MPa) load, a disk speed of 2500 - 20 mm / s for an SRR of 40% and an estimated temperature of 40 °C and 100 °C. The lower the coefficient of traction for a lubricant composition, the more friction is reduced between metal parts, resulting in greater gains in fuel economy. Example 1 The properties of re-refined lubricating oils II to 110, in accordance with the invention and commercially available, were evaluated. These oils are obtained from used base oils and have undergone at least one step of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passing the used lubricant over an adsorbent material, in particular at least one step of dehydration, distillation, liquid / liquid extraction and / or hydrogenation. Two new lubricating oils C1 and C2, which do not conform to the invention because they have not undergone any recycling or re-refining steps, were also evaluated. These oils are base oils of groups I or II according to the API classification, commercially available. In particular, the kinematic viscosity at 100°C, the viscosity index, the traction coefficients at 40°C and 100°C, as well as the Noack volatility of these oils were measured according to the protocols detailed above. The results are presented in Table 2 for re-refined and virgin oils whose characteristics are equivalent to those defined by the API classification for Group I base oils and in Table 3 for re-refined and virgin oils whose characteristics are equivalent to those defined by the API classification for Group II base oils, below. [Tables 2] 026 [an | 206 | ou | us mm |m |» | » | 15 22 | 175 | S58 | ND MD | ND ] XD |» | 40 00539 | 558 | astez | autsz | ons | 03597 | os4es | sous |s0s54| | 78 | 44,3 | 767 | 272 | 78 | 247 | 227 | #5 | es ose 0,628 | 9,021 | 2,0237 | 0,0217 | 00212 | 9,9254 | 66226 | 06237 | neass | | 23 | 265 | 239 | 256 | -05 | -207 | 68 ï 13 73 | 10,6 | ND | 95 16,7 | 19,6 | 132 | ss | Oil Cell | = B w# 5 tea r =: KV100 Francis} sa 87 45 42 83 s4 34 34 47 162 12 | 114 us F9 and Hs ns | 17 Tecmur breathing | L26 | 206 | or | mm |m|w | © | € Tech | #5 of 12 | 175 | ss | æ » |» | æ |æ | aromatic [201 cor pc ; ear 00539 | create | love | 062 | 00446 | 0.0497 | 60463 | 0075 |osss| SRE] Variation of COT by rgport | - | 8 | 445 | 167 | 72 | -28 | —4I | 217 | 25 | to Virgin Phudle There] cor gore : | 00285 | 0.021 | 0.037 | 0.5217 | 00212 | 0.254 | 6.0226 | 00237 | saxophone | SRR] Making the COTspeaker |. | —3| 163,238 | 256 | -109 | -207 168 | | to vfeige oil CI not Volatility Noack| 13 73 | 166 | D | 95,167 | 10.6 | 132 | you | 0%; [Tables3] I Be Tig If É- +4 315 ! 119 î1£ 82 | ND 4 2 ND 60484 | DO45 | 00413 00824 | 9,045 | -7.03 | 218 905244 | 40217 | 00193 | 00244 | 60217 | 2317 | -269 118 ' 1901 | 135 Oil c BB. KV100 [mm-s} 53 B2 Viscosity index 115 119 Sulfur content

[20] | <d.6003 | 002 teneur en aromatique os 9="°" cor 00484 9,045 40°c ; 40% srr] fariation du cot par rapport à l'huile -7,03 vierge c2 [7 cot 0.024 00217 {100°c 48% der -21,7 [% volatitité noack [%o} 118 ! 103 It can be observed that the re-refined lubricating oils according to the invention exhibit lower traction coefficients compared to the new reference oils. A lower coefficient of traction reduces friction losses in mechanical contacts operating in a full film, thus reducing fuel consumption. The coefficient of traction is lower over a wide temperature range (from 40 to 100°C), corresponding to engine crankcase temperatures. Furthermore, most re-refined lubricating oils exhibit reduced volatility compared to virgin oils. Lower base oil volatility allows for the use of more fluid base oils in lubricant formulations, further maximizing fuel economy gains.

Claims

Claims

1. Use of at least one lubricating oil at least partly re- refined to improve energy efficiency properties (“Energy efficiency”) of a lubricating composition intended for a system of motorization.

2. Use according to the preceding claim, to reduce the coefficient traction of the lubricating composition.

3. Use according to claim 1 or 2, for reducing Noack volatility of the lubricating composition.

4. Use according to any one of the preceding claims, in in which 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 lu- used abrasive on an adsorbent material.

5. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has characteristics in terms of content of saturated compounds, content of sulfur and viscosity index, meeting the criteria defined by the class- API specification for Group I oils or Group II oils.

6. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a kinematic viscosity measured at 100°C according to ASTM D445 su- greater than or equal to 4.0 mm? / s, in particular between 4.0 and 12 mm? / s, in particular greater than or equal to 4.3 mm” / s and more particu- mainly between 4.4 and 10 mm° / s, especially between 4.5 and 6 mm? Is.

7. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a viscosity index, determined according to standard NF ISO 2909, higher or equal to 110, in particular between 110 and 130, preferably between 112 and 125 and more particularly between 112 and 122.

8. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a Noack volatility, determined according to CEC L-40-93 standard, less than or equal to 15%, in particular less than or equal to 14%, preferably strictly less than 12%, in particular between 7% and 11%.

9. Use according to any one of the preceding claims, in which the lubricating oil is at least partly re-refined, in particular whose characteristics are equivalent to those defined by the classi- API certification for Group I or Group II base oils, has a reduced traction coefficient of at least 7%, in particular of at least 10%, advantageously of at least 15%, in particular of at least less 20%, or even at least 25%, compared to the coefficient of traction of a virgin base oil of equivalent group according to the classification API certification.

10. Use according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a sulfur content 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 at least partly re-refined lubricating oil has a content of aromatic compound(s) greater than or equal to 0.5% 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 lubricating oil at least partly re-refined.

12. Use according to any one of the preceding claims, in which said composition further comprises one or more oils base oils distinct from the at least partly re-refined lubricating oil and / or one or more additives, in particular chosen from mo- friction modifiers, anti-wear additives, extreme additives pressure, detergents, antioxidants, index improvers viscosity (VI), pour point depressant (PPD) additives, dispersants, antifoaming agents, thickeners, inhibitors of corrosion, copper passivating agents, and mixtures thereof.

13. | Use according to any one of the preceding claims, the or said at least partly re-refined lubricating oils representing more than 70% by mass of the total mass of the lubricating composition, in particular more than 80% by mass, in particular more than 90% mass and more particularly between 95% and 99% mass, by relative to the total mass of said lubricating composition.

14. Use of a lubricating composition based on at least one lubricating oil- at least partly re-refined, in particular as defined in claims 4 to 11, to reduce energy consumption of a motorization system lubricated by means of said composition lubricant.

15. Use according to claim 14, said motorization system being a mobile or stationary combustion engine system, electric or hybrid, especially in a vehicle, especially in a light vehicle, heavy goods vehicle or marine vehicle.