Use of specific base oil for reducing particulate emissions

Abstract

The present application relates to the use of a lubricant composition comprising a base oil or a base oil mixture having a viscosity (BOV or base oil viscosity) of less than or equal to 4, for reducing the particulate emissions of an engine.The present application relates to the use of a lubricant composition comprising a base oil or a mixture of base oils, for reducing the particulate emissions of an engine, in which said base oil or said mixture of base oils has a kinematic viscosity, measured at 100° C., of less than or equal to 4.5 mm2 / s, and in which said lubricant composition has a viscosity at 150° C. and under constant shear of greater than or equal to 2.4 mPa.s−1.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT / EP2023 / 062442 filed May 10, 2023, which claims priority of French Patent Application No. 22 10488, filed Oct. 12, 2022 and French Patent Application No. FR 22 04459, filed May 11, 2022. The entire contents of which are hereby incorporated by reference.FIELD OF THE INVENTION

[0002] The present invention relates to the use of a specific base for reducing particle emissions from motor vehicles.BACKGROUND

[0003] In 1993, the first European standard on emissions from vehicles with combustion engines was introduced. The standard Euro VI anti-pollution (standard EC 595 / 2009) relating to heavy goods vehicle engines came into force on 1 Sep. 2014 for newly approved vehicles and applicable to all new vehicles as of 1 Jan. 2014. The above standard concerns four pollutants in particular: carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particle mass (PM) and number (PN), amongst which soot, the last two remaining the most problematic for the pollution control system of modern engines.

[0004] Going after CO2 prompted manufacturers to increase the efficiency thereof so as to lower the consumptions. To this end, a for lean-burn operation (air in excess compared to the mass of fuel) was often chosen. Unfortunately, such a process generates a significant increase in the emissions of nitrogen oxide and particles.

[0005] In the past, manufacturers have also chosen to introduce particle filter systems for reducing the number and mass of particles emitted into the atmosphere. In most cases, the operation of such systems is based on the combustion of soot due to the temperature rise of the exhaust gases at the inlet of the filter. Such operation requires the presence of catalysis.

[0006] To comply with current and future standards, strict regulations on particle size and more particularly on the concentration in number of particles emitted (PN) have been introduced. Several studies have shown that, although particulate mass formation is low, the PN of particulates emitted by compressed natural gas (CNG) engines are not negligible compared to same of diesel engines, especially under high engine load conditions.

[0007] For the above reason, the new Euro VI emission standards prescribe a limit of 6×1011 particles per kWh, for diesel and CNG heavy vehicles.

[0008] The use of lubricant composition is considered to make a significant contribution to the emission of small particles (greater than 10 nm or 23 nm) emitted by the above type of engine.

[0009] There is an interest in providing lubricating compositions specifically suitable for reducing the number of particles emitted at the exhaust of a vehicle, in particular of a vehicle comprising at least one controlled ignition engine, preferably a combustion engine, in particular heavy or light vehicles, e.g. vehicles such as heavy goods vehicles.SUMMARY

[0010] A goal of the present invention is to provide a suitable lubricating composition having a direct impact on particle emissions.

[0011] Another goal of the present invention is to provide a specific base oil making the lubricating composition have a direct impact on particle emissions.

[0012] Further goals will emerge upon reading the following description of the invention.DETAILED DESCRIPTION

[0013] Such goals are fulfilled by the present application which relates to the use of a lubricating composition comprising a base oil or a mixture of base oils having a viscosity (BOV or Base Oil Viscosity) of less than or equal to 4.5 mm2 / s, in particular less than or equal to 4 mm2 / s, for reducing the particulate emissions from an engine.

[0014] The present invention also relates to the use of a lubricating composition comprising a base oil or a mixture of base oils, for reducing particulate emissions from an engine, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, of less than or equal to 4.5 mm2 / s, and wherein the lubricating composition has a viscosity at 150° C. and under constant shear of greater than or equal to 2.4 mPa.s−1.

[0015] In the context of the present invention, the term “particles” refers to the particles emitted by the exhaust of motor vehicles. It means a group of microscopic particles (about μm or less in size). Such substances are varied and are comprised in the vehicle exhaust gases coming from the combustion of fuel. Such substances can be either solid or liquid. The term particles comprises the term soots, which are formed, are oxidized and contain unburned hydrocarbons, oxygenated derivatives (ketones, esters, aldehydes, lactones, ethers, organic acids) and polycyclic aromatic hydrocarbons (the famous PAHs) along with the nitrated, oxygenated derivatives thereof, etc. There are further mineral (SO2, sulphates, etc.) and metal derivatives.

[0016] In a particularly advantageous manner, the present invention can be used for reducing the emissions of particles with a size greater than or equal to 10 nm, e.g. greater than 23 nm, or in particular equal to 10 nm.

[0017] Within the framework of the present invention, the term “particle size” refers to particles, or agglomerate of particles the size of which is comprised between 10 and 100 nm, e.g. between 10 and 60 nm, and else preferably 10 to 40 nm, e.g. between 23 and 100 nm, preferably between 23 and 60 nm, and else preferably between 23 and 40 nm.

[0018] The particle size can be measured by spectrometry, e.g. using a spectrometer manufactured by Cambustion under the commercial reference DMS500. The number of particles according to the size (PN10 or PN23) thereof can be determined e.g. using particle counters such as APC 489 marketed by AVL or else MEXA-2000 SPCS marketed by HORIBA.

[0019] Reduction of particle emissions refers, in particular, to the reduction of the number of particles, in particular of particles having a size greater than or equal to 10 nm, e.g. greater or equal to 23 nm. It is in particular a question of reducing the number of particles emitted during a cycle on a WHTC regulatory cycle, e.g. during WLTC or RDE cycles. Thereof is measured according to the work supplied over the cycle (in # / kWh). The reduction is also measured as a function of the number of kilometers traveled.

[0020] Preferably, the present application relates to the reduction of soot emissions.

[0021] Preferably, the present invention relates to the reduction of emissions of particles, preferably of particles with a size greater than or equal to 10 nm, e.g. greater than or equal to 23 nm, preferably of soots, over the entire regulatory cycle for heavy goods vehicle WHTC (World Harmonized Transient Cycle) applications.

[0022] Preferably, the present invention relates to the reduction of the emission of particles, preferably particles of size less than or equal to 23 nm, preferably soots, during the urban (low speed), peri-urban (moderate speed) and road (high speed) cycles defined by the WLTC (or WLTP) (Worldwide Harmonized Light Vehicle Test Procedure) and across all WLTC, and also over the RDE (Real Drive Emissions) cycle.

[0023] In the context of the present invention, viscosity (also called BOV for Base Oil Viscosity) is a kinematic viscosity and is measured at 100° C., according to the standard ASTM D445. The viscosity of the base oil at 100° C. corresponds to the kinematic viscosity of the base oil mixture at 100° C. of the formulation before the addition viscosity modifier additives and of a pour point depressor.

[0024] In the case of a base oil mixture, it should be understood that the viscosity of the base oil mixture is less than or equal to 4.

[0025] Preferably, the base oil or base oil mixture has a viscosity comprised between 1.5 and 4.

[0026] In the case of a mixture of base oils, it should be understood that it is the viscosity of the mixture of base oils which is preferably less than or equal to 4.5 mm2 / s.

[0027] Preferably, the base oil or the mixture of base oils has a kinematic viscosity, measured at 100° C., of from 1.5 to 4.5 mm2 / s, in particular from 1.5 to 4 mm2 / s.

[0028] According to one embodiment, the kinematic viscosity, measured at 100° C., of the base oil or of the mixture of base oils is comprised between 3 and 4.5 mm2 / s, and preferentially between 4 and 4.5 mm2 / s.

[0029] Preferably, the viscosity index of the base oil or of the mixture of base oils is greater than or equal to 130, preferably greater than or equal to 150.

[0030] The viscosity index is calculated by measuring the kinematic viscosity at 40° C. and 100° C. The measurements are then compared with the results of two reference oils. The method of calculation thereof is described in the standard ASTM D2270.

[0031] The lubricating composition according to the invention has e.g. a grade according to the SAEJ300 classification of type XW-(Y) with X representing 0, 5 or 10 and Y representing an integer comprised between 6 and 50, or comprised between 8 and 40, preferably 12 or 30 or 40.

[0032] The base oils used in the lubricating compositions of the invention can be oils of mineral or synthetic origin belonging to groups I to V according to the classes defined by the API classification (or the equivalents thereof according to the ATIEL classification (Table 1) or the mixtures thereof.TABLE 1Concentration ofSulfurViscositysaturatedconcen-indexsubstancestration(VI)Group I <90%>0.03%80 ≤ VI < 120Mineral oilsGroup II≥90%≤0.03%80 ≤ VI < 120Hydrocracked oilsGroup III≥90%≤0.03%≥120Hydro-isomerized oilsGroup IVPolyalphaolefins (PAO)Group VEsters and other bases notincluded in groups I to IV

[0033] The mineral base oils of the invention include any type of base oil obtained by atmospheric distillation and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreatment, hydrocracking, hydroisomerization and hydrofinishing.

[0034] The base oils of the lubricating compositions used according to the invention can be further chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, and polyalphaolefins. The polyalphaolefins used as base oil are e.g. obtained from monomers comprising from 4 to 32 carbon atoms, e.g. from octene or decene, and for which the viscosity at 100° C. is comprised between 1.5 and 15 mm2.s−1 as per the standard ASTM D445.

[0035] The lubricating composition used according to the invention can comprise at least 50% by weight of base oil with respect to the total weight of the composition. More advantageously, the lubricating composition according to the invention comprises at least 60% by weight, or even at least 70% by weight of base oils with respect to the total weight of the lubricating composition. In a more preferred way, the lubricating composition according to the invention comprises from 50% to 97% by weight of base oils, preferably from 50% to 85% by weight of base oils, or from 75% to 97% by weight of base oils with respect to the total weight of the composition.

[0036] According to one embodiment, the quantity of base oil or of the mixture of base oils is between 50% and 97% by weight with respect to the total weight of the lubricating composition as defined hereinabove.

[0037] As mentioned hereinabove, the lubricating composition used according to the invention preferably has a viscosity at 150° C. and under constant shear greater than or equal to 2.4 mPa.s−1. The viscosity is also referred to by the term HTHS 150.

[0038] HTHS (High Temperature, High Shear) viscosity is a measure of the viscosity of the residual oil film under high stress (shear under mechanical pressure) at high temperature. Herein, the HTHS 150 viscosity value is measured at 150° C. The values are measured as per the standards CEC L-036-90 or ASTM D4683.

[0039] According to one embodiment, the viscosity at 150° C., and under constant shear, of the lubricating composition (or HTHS 150) is comprised between 2.4 mPa.s−1 and 5 mPa.s−1, preferably between 2.6 mPa.s−1 and 5 mPa.s−1.

[0040] According to one embodiment, the lubricating composition used according to the invention has a grade according to the SAEJ300 classification of type XW-(Y) with X representing 0, 5 or 10 and Y representing an integer comprised from 6 to 50, preferably from 8 to 40, preferably 12, 20, 30 or 40, preferentially 20 or 30.

[0041] The lubricating composition used according to the invention may also comprise at least one viscosity index improving additive such as a butylene and hydrogenated styrene polymer, an ethylene propylene copolymer, or else a polymethacrylate polymer, preferably a butylene and hydrogenated styrene polymer. The lubricating composition according to the invention may thus also comprise at least one additive improving the viscosity index, chosen from the group consisting of hydrogenated butylene and styrene polymers, ethylene propylene copolymers and polymethacrylate polymers, said viscosity index improving additive preferably being a hydrogenated butylene and styrene polymer. The lubricating composition according to the invention can comprise from 0.1% to 15% by weight of additive improving the viscosity index, with respect to the total weight of lubricating composition.

[0042] The composition of the invention can further comprise at least one additive.

[0043] Many additives can be used in the lubricating compositions according to the invention.

[0044] The preferred additives for the lubricating composition according to the invention are chosen from detergent additives, friction modifying additives different from the molybdenum compounds defined above, extreme pressure additives, dispersants, pour point activators, antifoaming agents, thickeners and mixtures thereof.

[0045] Preferentially, the lubricating compositions according to the invention comprise at least one extreme pressure additive, or a mixture.

[0046] Anti-wear additives and extreme pressure additives protect surface friction by forming a protective film adsorbed on the surfaces.

[0047] There is a wide variety of anti-wear additives. Preferentially, for the lubricating compositions of the invention, the anti-wear additives are chosen from additives comprising phosphorus and sulfur, such as alkylthiophosphate metals, in particular zinc alkylthiophosphate, and more precisely zinc dialkyldithiophosphate or ZnDTP. Preferred compounds have the formula Zn((SP(S)(OR)(OR′))2, wherein R and R′—either identical or different—independently stands for an alkyl group, preferentially an alkyl group comprising from 1 to 18 carbon atoms.

[0048] Amine phosphates as well are anti-wear additives which can be used in the lubricating compositions of the invention. However, the phosphorus atoms provided by such additives can act as a poison in the catalytic systems of automobiles since same generate ash. Such effects can be minimized by substituting part of the amine phosphates with non-phosphorus additives, such as polysulfides, in particular sulfur-containing olefins.

[0049] Advantageously, the lubricating compositions according to the invention can comprise from 0.01% to 6% by weight, preferentially from 0.05% to 4% by weight, more preferentially from 0.1% to 2% by weight with respect to the total weight of lubricating composition of anti-wear additives and extreme pressure additives.

[0050] Advantageously, the lubricating compositions according to the invention comprise from 0.01% to 6% by weight, preferentially from 0.05% to 4% by weight, more preferentially from 0.1% to 2% by weight with respect to the total weight of lubricating composition, of anti-wear additives (or anti-wear compounds).

[0051] Advantageously, the compositions according to the invention can comprise at least one friction modifying additive different from the molybdenum compounds of the invention. The friction modifying additives can in particular be chosen from compounds providing metallic elements and ashless compounds. Compounds providing metal elements include complexes of transition metals such as Mo, Sb, Sn, Fe, Cu, Zn for which the ligands can be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus atoms. Ashless friction modifying additives are generally of organic origin or can be chosen from fatty acid and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, fatty amines or glycerol acid esters. According to the invention, fatty compounds comprise at least one hydrocarbon group comprising from 10 to 24 carbon atoms.

[0052] Advantageously, the lubricating composition according to the invention can comprise from 0.01% to 2% by weight or from 0.01% to 5% by weight, preferentially from 0.1% to 1.5% by weight or from 0.1% to 2% by weight with respect to the total weight of lubricating composition, of a friction modifier additive different from the molybdenum compounds according to the invention.

[0053] Advantageously, the lubricating composition according to the invention can comprise at least one antioxidant additive.

[0054] Antioxidant additives generally delay the degradation of the lubricating composition. Such degradation is most often expressed by a deposit formation, by the presence of sludge or by an increase in the viscosity of the lubricating composition.

[0055] Antioxidant additives generally act as radical inhibitors or hydroperoxide destructor inhibitors. Commonly used antioxidants include phenolic antioxidants, amine antioxidants, antioxidants containing sulfur and phosphorus. Some of the antioxidants, e.g. antioxidants containing sulfur and phosphorus, can generate ash. The phenolic antioxidant additives can be ashless or in the form of neutral or basic metal salts. The antioxidant additives can in particular be chosen from sterically hindered phenols, sterically hindered phenol esters, sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted with at least one C1 to C12 alkyl group, N,N′-dialkyl-aryl-diamines and mixtures thereof.

[0056] Preferentially, according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group for which at least one of the carbon atoms in the vicinity of the carbon atom bearing the alcohol function is substituted by at least one C1 to C10 alkyl group, preferentially a C1 to C6 alkyl group, preferentially a C4 alkyl group, preferentially a tert-butyl group.

[0057] Amine compounds are another class of antioxidant additives which can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, e.g. aromatic amines with the formula NRaRbRc wherein Ra stands for an aliphatic group or an optionally substituted aromatic group, Rb stands for an optionally substituted aromatic group, Rc stands for a hydrogen atom, an alkyl group, an aryl group or group with the formula RdS(O)zRe wherein Rd stands for an alkylene or alkenylene group, Re stands for an alkyl group, an alkenyl group or an aryl group, and z stands for 0, 1 or 2.

[0058] Alkyl phenols containing sulfur or the alkali or alkaline-earth metal salts thereof can further be used as antioxidant additives.

[0059] Other classes of antioxidant additives are compounds comprising copper, e.g. copper thio-or dithio-phosphate, copper salts and carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonates. Copper salts I and II, succinic acid salts or succinic anhydride salts can be further used.

[0060] The lubricating compositions used according to the invention can further comprise any type of antioxidant known to a person skilled in the art.

[0061] Advantageously, the lubricating composition used comprises at least one ashless antioxidant additive.

[0062] Further advantageously, the lubricating composition used according to the invention comprises from 0.1% to 2% by weight with respect to the total weight of the composition, of at least one antioxidant additive.

[0063] The lubricating composition used according to the invention can further comprise at least one detergent additive.

[0064] Detergent additives generally reduce the formation of deposits on the surface of metal parts, by dissolving oxidation and combustion by-products.

[0065] The detergent additives which can be used in the lubricating compositions according to the invention are generally known to a person skilled in the art. The detergent additives can be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophobic head. The associated cation can be a metal cation of an alkali or alkaline earth metal.

[0066] The detergent additives are preferentially chosen from alkali metal or alkaline-earth metal salts of carboxylic acid, sulphonates, salicylates, naphthenates, as well as phenate salts. The alkali metals and alkaline earth metals are preferentially calcium, magnesium, sodium or barium.

[0067] Such metal salts generally include the metal in a stoichiometric or in an excess amount, i.e. in a concentration greater than the stoichiometric concentration. Same are then overbased detergents; the excess of metal involving the overbased nature of the detergent additive is generally in the form of an oil-insoluble metal salt, e.g. carbonate, hydroxide, oxalate, acetate, glutamate, preferentially carbonate.

[0068] Advantageously, the lubricating composition used according to the invention can comprise from 0.5% to 8% or from 2% to 4% by weight with respect to the total weight of the lubricating composition, of an overbased detergent additive.

[0069] Further advantageously, the lubricating composition used according to the invention can further comprise an additive which lowers the pour point.

[0070] By slowing down the formation of paraffin crystals, the pour point lowering additive generally improves the behavior under cold conditions of the lubricating composition, according to the invention.

[0071] Examples of additives lowering the pour point include alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalene, alkyls polystyrenes.

[0072] Advantageously, the lubricating composition according to the invention can further comprise a dispersing agent.

[0073] The dispersing agents can be chosen from Mannich bases, succinimides and derivatives thereof.

[0074] Further advantageously, the lubricating composition according to the invention can comprise from 0.2% to 10% by weight with respect to the total weight of lubricating composition, of dispersing agent.

[0075] The lubricating composition according to the invention can further comprise at least one thickening agent.

[0076] The lubricating composition according to the invention can further comprise an antifoaming agent and a demulsifying agent.

[0077] The present invention further relates to the use of base oil with a viscosity less than or equal to 4 in an engine lubricating composition, so as to reduce particle emissions of said engine.

[0078] The present invention further relates to the use as defined hereinabove, wherein the reduction of particle emissions relates to the WLTC cycle or the RDE cycle, and more particularly to the reduction of emissions of particles with a size greater than or equal to 10 nm, e.g. comprised between 10 nm and 40 nm.

[0079] The present invention further relates to a method for reducing the emission of particles in an engine, preferentially a gas, gasoline, diesel or further hybrid engine, comprising the use of a lubricating composition comprising a base oil with a viscosity less than or equal to 4.

[0080] The present invention also relates to a method for reducing the emission of particles in an engine, in particular a controlled ignition engine, e.g. a combustion engine, preferably a gas, gasoline, diesel or hybrid engine, comprising the use of a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity at 150° C. and under constant shear greater than or equal to 2.4 mPa.s−1.

[0081] The present invention further relates to a method for reducing the emission of particles in an engine, preferably a gas, gasoline, diesel or hybrid engine, lubricated by a lubricating composition comprising the addition of a base oil with a viscosity less than or equal to 4, to said lubricating composition.

[0082] The present invention further relates to a method for reducing the emission of particles in an engine, preferably a gas, gasoline, diesel or hybrid engine, lubricated by a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity, at 150° C. and under constant shear, greater than or equal to 2.4 mPa.s−1.

[0083] In such methods, the particles, the base oil and the lubricating composition are as defined hereinabove.

[0084] The present invention covers all motor vehicles, in particular vehicles comprising a 2-stroke or 4-stroke engine, gasoline, diesel, hybrid or gas engines.

[0085] The present invention covers all motor vehicles, preferably comprising at least one controlled ignition engine, preferably a combustion engine, in particular heavy vehicles or light vehicles, preferably heavy goods vehicles.

[0086] The present invention will now be described with the help of non-limiting examples.EXAMPLE 1Lubricating Compositions

[0087] The following lubricating compositions were prepared according to Table 2 below.TABLE 2Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)((in % with(in % with(in % with(in % with(in % with(in % withrespect torespect torespect torespect torespect torespect tothe totalthe totalthe totalthe totalthe totalthe totalweight of theweight of theweight of theweight of theweight of theweight of thecomposition)composition)composition)composition)composition)composition)Grade10W-4010W-405W-305W-300W-400W-30Additive21.411.321.411.321.421.4 packageMineral base76.184.57682.868.873.1oil (group III)(mixture oftwo baseoils)Base oil684432.9viscosityHydrogenated2.54.22.65.99.85.5styrenebutadienepolymer

[0088] The characteristics of the lubricating compositions are collated in Table 3 below:TABLE 3Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)KV 40° C.91.5794.3256.7652.4574.2250.3ASTMD445-97or ISO3104(mm2 / s)KV 100° C.13.4913.89.7479.75113.539.674ASTMD445-97or ISO 3104(mm2 / s)VI147149158174188181(ISO 3104)HTHS 150° C.43.863.142.993.833.85CEC L14-90(mPa · s)Noack 1 h6.54.612.213.631.532250° C.CEC L-040-93(%)EXAMPLE 2Measurement of the Number of Emitted Particles and of Fuel Eco

[0089] The compositions of example 1 were tested over the WHTC cycle and the quantity of particles having a size greater than or equal to 10 nm emitted at the end of each cycle was measured.

[0090] The engine tests were carried out on turbocharged straight-six engines. The tests were carried out at the same starting temperature of the engine. All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases ahead from the exhaust system but after the treatment systems. Thereby, the effects observed are indeed due solely to the use of the lubricating composition and not to any other criterion such as the temperature, the humidity, etc.

[0091] The particle size distribution was measured in parallel by a Cambustion differential mobility spectrometer (DMS500). Same uses a high voltage discharge for charging every particle proportionally to the surface thereof. The charged particles are introduced into a classification section with a strong radial electric field. Such field causes particles to drift through a flow inside a column, toward the electrometer detectors. The particles are detected at different distances in the column, depending on the aerodynamic resistance / Icharge ratio thereof. The outputs of the 22 electrometers are processed in real-time at 10 Hz, so as to provide spectral data and other measurements.

[0092] Fuel consumption was also measured and calculated by the following equation:Fuel⁢ consumption=Total⁢ mass⁢ of⁢ fuel⁢ injected [g]cycle [kWh]

[0093] The emissions of particles were calculated as follows:Emissions⁢ of⁢ particles=Total⁢ number⁢ of⁢ particles [#]cycle [kWh]

[0094] The results are given in Table 4 hereinbelow:TABLE 4Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)Fuel248249246249249245consumption(g / kWh)Emissions of5.75 × 10123.78 × 10122.52 × 10122.18 × 10121.72 × 10121.56 × 1012particles(number / kWh)

[0095] The results clearly show that the choice of the base oil according to the invention (viscosity less than or equal to 4) clearly reduces particle emission. The results also show that the choice of the base oil according to the invention has no impact on the consumption of fuel (Fuel Eco), thereby showing that a reduction in particle emissions is not synonymous with an improvement of Fuel Eco.EXAMPLE 31st Testing CampaignPreparation of Lubricating Compositions The lubricating compositions were prepared according to Table 5 hereinafter.TABLE 5Composition 6Composition 7Composition 8Composition 9Composition 10(comparative)(comparative)(reference oil)(invention)(invention)Grade0W120W200W200W200W20Package of1414141414additivesBase oilBOV 4Mixture ofBOV 4Mixture of 90%Mixture ofGroup IIIgroup III baseGroup IIIBOV 4 Group IIIgroup III baseBase oiloils: 43% BOVBase oilbase oil andoils: 70% BOV4 oil and 57%10% BOV 64 oil and 30%BOV 6Group IVBOV 3base oilPISH0.4044.45.6polymerPMA00000polymerComposition 11Composition 12Composition 13Composition 14(invention)(invention)(invention)(invention)Grade0W20XW30XW30XW30Package of14141414additivesBase oilBOV 3BOV 3BOV 4BOV 4Group IIIGroup IIIGroup IIIGroup IIIBase oilBase oilBase oilBase oilPISH712.510.20polymerPAMA00010.0polymer

[0096] The numbers in Table 5 correspond to percentages by weight with respect to the total weight of composition.

[0097] The characteristics of the lubricating compositions are given in Table 6 below:TABLE 6Compo. 6Compo. 7Compo. 8Compo. 9Compo. 10(comp.)(comp.)(reference oil)(invention)(invention)HTHS 1502.172.552.642.62.6(mPa · s−1)CEC L-036-90 orASTM D4683Base oil viscosity4.3245.5784.3244.3043.918(100° C.)ASTM D445-97(mm2 / s)Noack volatility10.77.711.110.815.2ASTM D5800 orCEC L-040-93Compo. 11Compo. 12Compo. 13(invention)(invention)(invention)HTHS 1503.493.523.42(mPa · s−1)CEC L-036-90 orASTM D4683Base oil viscosity3.3204.3244.324(100° C.)ASTM D445-97(mm2 / s)Noack volatility2110.711.4ASTM D5800 or CECL-040-93Measurement of the Number of Emitted Particles

[0098] The compositions of example 3 were subjected to the WLTC or RDE tests and the quantity of particles per kilometer traveled having a size greater than or equal to 10 nm emitted at the end of each cycle was measured. An EB2ADTS (PSA Peugeot Citroën) engine with a displacement of 1.2 I (maximum power of 60 KW) was used.

[0099] The engine tests were carried out on turbocharged straight-three engines. The tests were carried out at the same starting temperature of the engine (20° C.). All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases at the outlet of the turbocharger and upstream of the post-treatment system.

[0100] The particle number was measured using a Horiba MEXA2000-SPCS particle counter equipped with an overhead diluter. Each lubricating composition was tested 10 times on a WLTC cycle (with forced cooling at 20° C. at the beginning of each cycle). The first 3 cycles were deliberately discarded to allow the injection system to stabilize. The other 7 cycles were taken into account for the results. Particle numbers were expressed as average particle numbers (PN10 and PN23) per kilometer over the cycle considered.

[0101] The test campaign was thus carried out on an iso-additivation matrix.

[0102] The results are given in Tables 7 and 8 hereinafter, which relate to the WLTC and RDE cycles, respectively.

[0103] The test of a reference oil (composition 8) provides a framework for each test. The test results are expressed with respect to the result of the last reference oil passed.TABLE 7Change of the number of particles(PN10) in comparison with theWLTC cyclecomposition 8Composition 6+23%(comparative)Composition 7+34%(comparative)Composition 9 −8%(invention)Composition 10−18%(invention)Composition 11−46%(invention)Composition 12−28%(invention)Composition 13−26%(invention)TABLE 8Change of the number of particles(PN10) in comparison with theRDE cyclecomposition 8Composition 6 +5%(comparative)Composition 7+12%(comparative)Composition 9−11%(invention)Composition 10−17%(invention)Composition 11−24%(invention)Composition 12 −4%(invention)Composition 13−22%(invention)The results of Tables 7 and 8 demonstrate that the compositions used according to the invention effectively serve to reduce the number of particles with a size greater than or equal to 10 nm, over a WLTC or RDE cycle.

[0105] Tables 9 and 10 hereinafter summarize the results obtained on an RDE or WLTC cycle for composition 8 as regards the particles with a size of 10 nm. The results show the repeatability of the effect of decreasing the emission of PN10 particles.TABLE 9Tests12345678#PN10 per2.26 ×2.04 ×2.23 ×1.89 ×1.61 ×1.64 ×1.84 ×1.64 ×km traveled10121012101210121012101210121012over WLTCcycle#PN10 per4.88 ×4.34 ×4.32 ×4.17 ×3.57 ×3.52 ×3.75 ×3.63 ×km traveled10121012101210121012101210121012over RDEcycleTABLE 10Reference oilPN10PN10Composition 8WLTCRDEMean value1.88E123.97E12Standard deviation0.25E120.48E12Standard Deviation / mean13%12%Repeatability (IC95)0.69E121.34E12Repeatability / average37%34%EXAMPLE 42nd Testing CampaignA second testing campaign was carried out. Lubricants differ in viscosity grade but also in the composition of additives and of base oils. Table 11 shows the characteristics of the lubricating compositions which demonstrate an influence of the viscosity grade on the reduction of the PN10 number, independently of the composition:TABLE 11Compo. 14Compo. 15Compo. 16Compo. 9Compo. 17(Inv.)(inv.)(inv.)(inv.)(inv.)Grade0W200W200W200W200W30Package ofA (14%)A (14%)A (14%)A (14%)B (12%)additivesBase oilBOV 4BOV 4BOV 4Mixture ofMixture ofGroup IIIGroup IIIGroup III90% BOV 440% BOV 4Base oilBase oilBase oilGroup IIIGroup IIIbase oil andbase oil, 40% BOV10% BOV 64 Group IVGroup IVbase oil andbase oil20% BOV 5Group IIIbase oilPISH polymer44.444.43.2PMA polymer2.9HTHS 1502.632.612.642.63.03(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.8.3798.2478.2288.2919.840ASTM D445-97(mm2 / s)Compo. 18Compo. 19Compo. 20Compo. 21Compo. 22(inv.)(inv.)(inv.)(comp.)(comp.)Grade0W305W305W400W120W12Package ofC (13%%)D (15%)E (13.3%)F (13%)F (13%)additivesBase oilMixture ofMixture ofMixture ofMixture ofMixture of70% BOV 445% BOV 655% BOV 455% BOV 438% BOV 4Group IIIGroup IIIGroup IIIGroup IIIGroup IIIbase oil,base oil andbase oil andbase oil,base oil,10% BOV 455% BOV 645% BOV 817% BOV 334% BOV 3Group IVGroup IVGroup IVGroup IIIGroup IIIbase oil andbase oilbase oilbase oil andbase oil and20% BOV 528% BOV 328% BOV 3Group IIIGroup VGroup Vbase oilbase oilbase oilPISH polymer3.28.78.356PMA polymer2.70000HTHS 1503.013.503.782.112.11(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.9.89011.2814.545.9785.967ASTM D445-97(mm2 / s)Compo. 23Compo. 24(comp.)(comp.)Grade0W120W12Package of additivesG (13.5%)G (13.5%)Base oilBOV 4BOV 4Group IIIGroup IIIBase oilBase oilPISH polymer00PMA polymer00HTHS 1501.922.00(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.5.4575.868ASTM D445-97 (mm2 / s)Table 12 hereinafter shows the results obtained over a WLTC cycle with regard to the particles with a size of 10 nm.TABLE 12Amount of particles perkilometer traveled with a sizegreater than or equal to 10 nmComposition 14 (invention)2.84E+12Composition 15 (invention)2.49E+12Composition 16 (invention)2.39E+12Composition 17 (invention)2.25E+12Composition 10 (invention)1.25E+12Composition 18 (invention)1.14E+12Composition 19 (invention)1.75E+12Composition 20 (invention)5.00E+11Composition 21 (comparative)3.79E+12Composition 22 (comparative)4.35E+12Composition 23 (comparative)4.18E+12Composition 24 (comparative)4.01E+12The results show that the use of a lubricating composition according to the invention reduces the quantity of particles with a size greater than or equal to 10 nm.

Examples

example 1

Lubricating Compositions

[0087]The following lubricating compositions were prepared according to Table 2 below.

TABLE 2Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)((in % with(in % with(in % with(in % with(in % with(in % withrespect torespect torespect torespect torespect torespect tothe totalthe totalthe totalthe totalthe totalthe totalweight of theweight of theweight of theweight of theweight of theweight of thecomposition)composition)composition)composition)composition)composition)Grade10W-4010W-405W-305W-300W-400W-30Additive21.411.321.411.321.421.4 packageMineral base76.184.57682.868.873.1oil (group III)(mixture oftwo baseoils)Base oil684432.9viscosityHydrogenated2.54.22.65.99.85.5styrenebutadienepolymer

[0088]The characteristics of the lubricating compositions are collated in Table 3 below:

TABLE 3Composition 2Composition 3...

example 2

Measurement of the Number of Emitted Particles and of Fuel Eco

[0089]The compositions of example 1 were tested over the WHTC cycle and the quantity of particles having a size greater than or equal to 10 nm emitted at the end of each cycle was measured.

[0090]The engine tests were carried out on turbocharged straight-six engines. The tests were carried out at the same starting temperature of the engine. All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases ahead from the exhaust system but after the treatment systems. Thereby, the effects observed are indeed due solely to the use of the lubricating composition and not to any other criterion such as the temperature, the humidity, etc.

[0091]The particle size distribution was measured in parallel by a Cambustion differential mobility spectrometer (DMS500). Same uses a high voltage discharge for charging every particle proportionally to the surface there...

example 3

1st Testing Campaign

Preparation of Lubricating Compositions The lubricating compositions were prepared according to Table 5 hereinafter.

TABLE 5Composition 6Composition 7Composition 8Composition 9Composition 10(comparative)(comparative)(reference oil)(invention)(invention)Grade0W120W200W200W200W20Package of1414141414additivesBase oilBOV 4Mixture ofBOV 4Mixture of 90%Mixture ofGroup IIIgroup III baseGroup IIIBOV 4 Group IIIgroup III baseBase oiloils: 43% BOVBase oilbase oil andoils: 70% BOV4 oil and 57%10% BOV 64 oil and 30%BOV 6Group IVBOV 3base oilPISH0.4044.45.6polymerPMA00000polymerComposition 11Composition 12Composition 13Composition 14(invention)(invention)(invention)(invention)Grade0W20XW30XW30XW30Package of14141414additivesBase oilBOV 3BOV 3BOV 4BOV 4Group IIIGroup IIIGroup IIIGroup IIIBase oilBase oilBase oilBase oilPISH712.510.20polymerPAMA00010.0polymer

[0096]The numbers in Table 5 correspond to percentages by weight with respect to the total weight of composition.

[0097]The ...

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT / EP2023 / 062442 filed May 10, 2023, which claims priority of French Patent Application No. 22 10488, filed Oct. 12, 2022 and French Patent Application No. FR 22 04459, filed May 11, 2022. The entire contents of which are hereby incorporated by reference.FIELD OF THE INVENTION

[0002] The present invention relates to the use of a specific base for reducing particle emissions from motor vehicles.BACKGROUND

[0003] In 1993, the first European standard on emissions from vehicles with combustion engines was introduced. The standard Euro VI anti-pollution (standard EC 595 / 2009) relating to heavy goods vehicle engines came into force on 1 Sep. 2014 for newly approved vehicles and applicable to all new vehicles as of 1 Jan. 2014. The above standard concerns four pollutants in particular: carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particle mass (PM) and number (PN), amongst which soot, the last two remaining the most problematic for the pollution control system of modern engines.

[0004] Going after CO2 prompted manufacturers to increase the efficiency thereof so as to lower the consumptions. To this end, a for lean-burn operation (air in excess compared to the mass of fuel) was often chosen. Unfortunately, such a process generates a significant increase in the emissions of nitrogen oxide and particles.

[0005] In the past, manufacturers have also chosen to introduce particle filter systems for reducing the number and mass of particles emitted into the atmosphere. In most cases, the operation of such systems is based on the combustion of soot due to the temperature rise of the exhaust gases at the inlet of the filter. Such operation requires the presence of catalysis.

[0006] To comply with current and future standards, strict regulations on particle size and more particularly on the concentration in number of particles emitted (PN) have been introduced. Several studies have shown that, although particulate mass formation is low, the PN of particulates emitted by compressed natural gas (CNG) engines are not negligible compared to same of diesel engines, especially under high engine load conditions.

[0007] For the above reason, the new Euro VI emission standards prescribe a limit of 6×1011 particles per kWh, for diesel and CNG heavy vehicles.

[0008] The use of lubricant composition is considered to make a significant contribution to the emission of small particles (greater than 10 nm or 23 nm) emitted by the above type of engine.

[0009] There is an interest in providing lubricating compositions specifically suitable for reducing the number of particles emitted at the exhaust of a vehicle, in particular of a vehicle comprising at least one controlled ignition engine, preferably a combustion engine, in particular heavy or light vehicles, e.g. vehicles such as heavy goods vehicles.SUMMARY

[0010] A goal of the present invention is to provide a suitable lubricating composition having a direct impact on particle emissions.

[0011] Another goal of the present invention is to provide a specific base oil making the lubricating composition have a direct impact on particle emissions.

[0012] Further goals will emerge upon reading the following description of the invention.DETAILED DESCRIPTION

[0013] Such goals are fulfilled by the present application which relates to the use of a lubricating composition comprising a base oil or a mixture of base oils having a viscosity (BOV or Base Oil Viscosity) of less than or equal to 4.5 mm2 / s, in particular less than or equal to 4 mm2 / s, for reducing the particulate emissions from an engine.

[0014] The present invention also relates to the use of a lubricating composition comprising a base oil or a mixture of base oils, for reducing particulate emissions from an engine, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, of less than or equal to 4.5 mm2 / s, and wherein the lubricating composition has a viscosity at 150° C. and under constant shear of greater than or equal to 2.4 mPa.s−1.

[0015] In the context of the present invention, the term “particles” refers to the particles emitted by the exhaust of motor vehicles. It means a group of microscopic particles (about μm or less in size). Such substances are varied and are comprised in the vehicle exhaust gases coming from the combustion of fuel. Such substances can be either solid or liquid. The term particles comprises the term soots, which are formed, are oxidized and contain unburned hydrocarbons, oxygenated derivatives (ketones, esters, aldehydes, lactones, ethers, organic acids) and polycyclic aromatic hydrocarbons (the famous PAHs) along with the nitrated, oxygenated derivatives thereof, etc. There are further mineral (SO2, sulphates, etc.) and metal derivatives.

[0016] In a particularly advantageous manner, the present invention can be used for reducing the emissions of particles with a size greater than or equal to 10 nm, e.g. greater than 23 nm, or in particular equal to 10 nm.

[0017] Within the framework of the present invention, the term “particle size” refers to particles, or agglomerate of particles the size of which is comprised between 10 and 100 nm, e.g. between 10 and 60 nm, and else preferably 10 to 40 nm, e.g. between 23 and 100 nm, preferably between 23 and 60 nm, and else preferably between 23 and 40 nm.

[0018] The particle size can be measured by spectrometry, e.g. using a spectrometer manufactured by Cambustion under the commercial reference DMS500. The number of particles according to the size (PN10 or PN23) thereof can be determined e.g. using particle counters such as APC 489 marketed by AVL or else MEXA-2000 SPCS marketed by HORIBA.

[0019] Reduction of particle emissions refers, in particular, to the reduction of the number of particles, in particular of particles having a size greater than or equal to 10 nm, e.g. greater or equal to 23 nm. It is in particular a question of reducing the number of particles emitted during a cycle on a WHTC regulatory cycle, e.g. during WLTC or RDE cycles. Thereof is measured according to the work supplied over the cycle (in # / kWh). The reduction is also measured as a function of the number of kilometers traveled.

[0020] Preferably, the present application relates to the reduction of soot emissions.

[0021] Preferably, the present invention relates to the reduction of emissions of particles, preferably of particles with a size greater than or equal to 10 nm, e.g. greater than or equal to 23 nm, preferably of soots, over the entire regulatory cycle for heavy goods vehicle WHTC (World Harmonized Transient Cycle) applications.

[0022] Preferably, the present invention relates to the reduction of the emission of particles, preferably particles of size less than or equal to 23 nm, preferably soots, during the urban (low speed), peri-urban (moderate speed) and road (high speed) cycles defined by the WLTC (or WLTP) (Worldwide Harmonized Light Vehicle Test Procedure) and across all WLTC, and also over the RDE (Real Drive Emissions) cycle.

[0023] In the context of the present invention, viscosity (also called BOV for Base Oil Viscosity) is a kinematic viscosity and is measured at 100° C., according to the standard ASTM D445. The viscosity of the base oil at 100° C. corresponds to the kinematic viscosity of the base oil mixture at 100° C. of the formulation before the addition viscosity modifier additives and of a pour point depressor.

[0024] In the case of a base oil mixture, it should be understood that the viscosity of the base oil mixture is less than or equal to 4.

[0025] Preferably, the base oil or base oil mixture has a viscosity comprised between 1.5 and 4.

[0026] In the case of a mixture of base oils, it should be understood that it is the viscosity of the mixture of base oils which is preferably less than or equal to 4.5 mm2 / s.

[0027] Preferably, the base oil or the mixture of base oils has a kinematic viscosity, measured at 100° C., of from 1.5 to 4.5 mm2 / s, in particular from 1.5 to 4 mm2 / s.

[0028] According to one embodiment, the kinematic viscosity, measured at 100° C., of the base oil or of the mixture of base oils is comprised between 3 and 4.5 mm2 / s, and preferentially between 4 and 4.5 mm2 / s.

[0029] Preferably, the viscosity index of the base oil or of the mixture of base oils is greater than or equal to 130, preferably greater than or equal to 150.

[0030] The viscosity index is calculated by measuring the kinematic viscosity at 40° C. and 100° C. The measurements are then compared with the results of two reference oils. The method of calculation thereof is described in the standard ASTM D2270.

[0031] The lubricating composition according to the invention has e.g. a grade according to the SAEJ300 classification of type XW-(Y) with X representing 0, 5 or 10 and Y representing an integer comprised between 6 and 50, or comprised between 8 and 40, preferably 12 or 30 or 40.

[0032] The base oils used in the lubricating compositions of the invention can be oils of mineral or synthetic origin belonging to groups I to V according to the classes defined by the API classification (or the equivalents thereof according to the ATIEL classification (Table 1) or the mixtures thereof.TABLE 1Concentration ofSulfurViscositysaturatedconcen-indexsubstancestration(VI)Group I <90%>0.03%80 ≤ VI < 120Mineral oilsGroup II≥90%≤0.03%80 ≤ VI < 120Hydrocracked oilsGroup III≥90%≤0.03%≥120Hydro-isomerized oilsGroup IVPolyalphaolefins (PAO)Group VEsters and other bases notincluded in groups I to IV

[0033] The mineral base oils of the invention include any type of base oil obtained by atmospheric distillation and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreatment, hydrocracking, hydroisomerization and hydrofinishing.

[0034] The base oils of the lubricating compositions used according to the invention can be further chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, and polyalphaolefins. The polyalphaolefins used as base oil are e.g. obtained from monomers comprising from 4 to 32 carbon atoms, e.g. from octene or decene, and for which the viscosity at 100° C. is comprised between 1.5 and 15 mm2.s−1 as per the standard ASTM D445.

[0035] The lubricating composition used according to the invention can comprise at least 50% by weight of base oil with respect to the total weight of the composition. More advantageously, the lubricating composition according to the invention comprises at least 60% by weight, or even at least 70% by weight of base oils with respect to the total weight of the lubricating composition. In a more preferred way, the lubricating composition according to the invention comprises from 50% to 97% by weight of base oils, preferably from 50% to 85% by weight of base oils, or from 75% to 97% by weight of base oils with respect to the total weight of the composition.

[0036] According to one embodiment, the quantity of base oil or of the mixture of base oils is between 50% and 97% by weight with respect to the total weight of the lubricating composition as defined hereinabove.

[0037] As mentioned hereinabove, the lubricating composition used according to the invention preferably has a viscosity at 150° C. and under constant shear greater than or equal to 2.4 mPa.s−1. The viscosity is also referred to by the term HTHS 150.

[0038] HTHS (High Temperature, High Shear) viscosity is a measure of the viscosity of the residual oil film under high stress (shear under mechanical pressure) at high temperature. Herein, the HTHS 150 viscosity value is measured at 150° C. The values are measured as per the standards CEC L-036-90 or ASTM D4683.

[0039] According to one embodiment, the viscosity at 150° C., and under constant shear, of the lubricating composition (or HTHS 150) is comprised between 2.4 mPa.s−1 and 5 mPa.s−1, preferably between 2.6 mPa.s−1 and 5 mPa.s−1.

[0040] According to one embodiment, the lubricating composition used according to the invention has a grade according to the SAEJ300 classification of type XW-(Y) with X representing 0, 5 or 10 and Y representing an integer comprised from 6 to 50, preferably from 8 to 40, preferably 12, 20, 30 or 40, preferentially 20 or 30.

[0041] The lubricating composition used according to the invention may also comprise at least one viscosity index improving additive such as a butylene and hydrogenated styrene polymer, an ethylene propylene copolymer, or else a polymethacrylate polymer, preferably a butylene and hydrogenated styrene polymer. The lubricating composition according to the invention may thus also comprise at least one additive improving the viscosity index, chosen from the group consisting of hydrogenated butylene and styrene polymers, ethylene propylene copolymers and polymethacrylate polymers, said viscosity index improving additive preferably being a hydrogenated butylene and styrene polymer. The lubricating composition according to the invention can comprise from 0.1% to 15% by weight of additive improving the viscosity index, with respect to the total weight of lubricating composition.

[0042] The composition of the invention can further comprise at least one additive.

[0043] Many additives can be used in the lubricating compositions according to the invention.

[0044] The preferred additives for the lubricating composition according to the invention are chosen from detergent additives, friction modifying additives different from the molybdenum compounds defined above, extreme pressure additives, dispersants, pour point activators, antifoaming agents, thickeners and mixtures thereof.

[0045] Preferentially, the lubricating compositions according to the invention comprise at least one extreme pressure additive, or a mixture.

[0046] Anti-wear additives and extreme pressure additives protect surface friction by forming a protective film adsorbed on the surfaces.

[0047] There is a wide variety of anti-wear additives. Preferentially, for the lubricating compositions of the invention, the anti-wear additives are chosen from additives comprising phosphorus and sulfur, such as alkylthiophosphate metals, in particular zinc alkylthiophosphate, and more precisely zinc dialkyldithiophosphate or ZnDTP. Preferred compounds have the formula Zn((SP(S)(OR)(OR′))2, wherein R and R′—either identical or different—independently stands for an alkyl group, preferentially an alkyl group comprising from 1 to 18 carbon atoms.

[0048] Amine phosphates as well are anti-wear additives which can be used in the lubricating compositions of the invention. However, the phosphorus atoms provided by such additives can act as a poison in the catalytic systems of automobiles since same generate ash. Such effects can be minimized by substituting part of the amine phosphates with non-phosphorus additives, such as polysulfides, in particular sulfur-containing olefins.

[0049] Advantageously, the lubricating compositions according to the invention can comprise from 0.01% to 6% by weight, preferentially from 0.05% to 4% by weight, more preferentially from 0.1% to 2% by weight with respect to the total weight of lubricating composition of anti-wear additives and extreme pressure additives.

[0050] Advantageously, the lubricating compositions according to the invention comprise from 0.01% to 6% by weight, preferentially from 0.05% to 4% by weight, more preferentially from 0.1% to 2% by weight with respect to the total weight of lubricating composition, of anti-wear additives (or anti-wear compounds).

[0051] Advantageously, the compositions according to the invention can comprise at least one friction modifying additive different from the molybdenum compounds of the invention. The friction modifying additives can in particular be chosen from compounds providing metallic elements and ashless compounds. Compounds providing metal elements include complexes of transition metals such as Mo, Sb, Sn, Fe, Cu, Zn for which the ligands can be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus atoms. Ashless friction modifying additives are generally of organic origin or can be chosen from fatty acid and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, fatty amines or glycerol acid esters. According to the invention, fatty compounds comprise at least one hydrocarbon group comprising from 10 to 24 carbon atoms.

[0052] Advantageously, the lubricating composition according to the invention can comprise from 0.01% to 2% by weight or from 0.01% to 5% by weight, preferentially from 0.1% to 1.5% by weight or from 0.1% to 2% by weight with respect to the total weight of lubricating composition, of a friction modifier additive different from the molybdenum compounds according to the invention.

[0053] Advantageously, the lubricating composition according to the invention can comprise at least one antioxidant additive.

[0054] Antioxidant additives generally delay the degradation of the lubricating composition. Such degradation is most often expressed by a deposit formation, by the presence of sludge or by an increase in the viscosity of the lubricating composition.

[0055] Antioxidant additives generally act as radical inhibitors or hydroperoxide destructor inhibitors. Commonly used antioxidants include phenolic antioxidants, amine antioxidants, antioxidants containing sulfur and phosphorus. Some of the antioxidants, e.g. antioxidants containing sulfur and phosphorus, can generate ash. The phenolic antioxidant additives can be ashless or in the form of neutral or basic metal salts. The antioxidant additives can in particular be chosen from sterically hindered phenols, sterically hindered phenol esters, sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted with at least one C1 to C12 alkyl group, N,N′-dialkyl-aryl-diamines and mixtures thereof.

[0056] Preferentially, according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group for which at least one of the carbon atoms in the vicinity of the carbon atom bearing the alcohol function is substituted by at least one C1 to C10 alkyl group, preferentially a C1 to C6 alkyl group, preferentially a C4 alkyl group, preferentially a tert-butyl group.

[0057] Amine compounds are another class of antioxidant additives which can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, e.g. aromatic amines with the formula NRaRbRc wherein Ra stands for an aliphatic group or an optionally substituted aromatic group, Rb stands for an optionally substituted aromatic group, Rc stands for a hydrogen atom, an alkyl group, an aryl group or group with the formula RdS(O)zRe wherein Rd stands for an alkylene or alkenylene group, Re stands for an alkyl group, an alkenyl group or an aryl group, and z stands for 0, 1 or 2.

[0058] Alkyl phenols containing sulfur or the alkali or alkaline-earth metal salts thereof can further be used as antioxidant additives.

[0059] Other classes of antioxidant additives are compounds comprising copper, e.g. copper thio-or dithio-phosphate, copper salts and carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonates. Copper salts I and II, succinic acid salts or succinic anhydride salts can be further used.

[0060] The lubricating compositions used according to the invention can further comprise any type of antioxidant known to a person skilled in the art.

[0061] Advantageously, the lubricating composition used comprises at least one ashless antioxidant additive.

[0062] Further advantageously, the lubricating composition used according to the invention comprises from 0.1% to 2% by weight with respect to the total weight of the composition, of at least one antioxidant additive.

[0063] The lubricating composition used according to the invention can further comprise at least one detergent additive.

[0064] Detergent additives generally reduce the formation of deposits on the surface of metal parts, by dissolving oxidation and combustion by-products.

[0065] The detergent additives which can be used in the lubricating compositions according to the invention are generally known to a person skilled in the art. The detergent additives can be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophobic head. The associated cation can be a metal cation of an alkali or alkaline earth metal.

[0066] The detergent additives are preferentially chosen from alkali metal or alkaline-earth metal salts of carboxylic acid, sulphonates, salicylates, naphthenates, as well as phenate salts. The alkali metals and alkaline earth metals are preferentially calcium, magnesium, sodium or barium.

[0067] Such metal salts generally include the metal in a stoichiometric or in an excess amount, i.e. in a concentration greater than the stoichiometric concentration. Same are then overbased detergents; the excess of metal involving the overbased nature of the detergent additive is generally in the form of an oil-insoluble metal salt, e.g. carbonate, hydroxide, oxalate, acetate, glutamate, preferentially carbonate.

[0068] Advantageously, the lubricating composition used according to the invention can comprise from 0.5% to 8% or from 2% to 4% by weight with respect to the total weight of the lubricating composition, of an overbased detergent additive.

[0069] Further advantageously, the lubricating composition used according to the invention can further comprise an additive which lowers the pour point.

[0070] By slowing down the formation of paraffin crystals, the pour point lowering additive generally improves the behavior under cold conditions of the lubricating composition, according to the invention.

[0071] Examples of additives lowering the pour point include alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalene, alkyls polystyrenes.

[0072] Advantageously, the lubricating composition according to the invention can further comprise a dispersing agent.

[0073] The dispersing agents can be chosen from Mannich bases, succinimides and derivatives thereof.

[0074] Further advantageously, the lubricating composition according to the invention can comprise from 0.2% to 10% by weight with respect to the total weight of lubricating composition, of dispersing agent.

[0075] The lubricating composition according to the invention can further comprise at least one thickening agent.

[0076] The lubricating composition according to the invention can further comprise an antifoaming agent and a demulsifying agent.

[0077] The present invention further relates to the use of base oil with a viscosity less than or equal to 4 in an engine lubricating composition, so as to reduce particle emissions of said engine.

[0078] The present invention further relates to the use as defined hereinabove, wherein the reduction of particle emissions relates to the WLTC cycle or the RDE cycle, and more particularly to the reduction of emissions of particles with a size greater than or equal to 10 nm, e.g. comprised between 10 nm and 40 nm.

[0079] The present invention further relates to a method for reducing the emission of particles in an engine, preferentially a gas, gasoline, diesel or further hybrid engine, comprising the use of a lubricating composition comprising a base oil with a viscosity less than or equal to 4.

[0080] The present invention also relates to a method for reducing the emission of particles in an engine, in particular a controlled ignition engine, e.g. a combustion engine, preferably a gas, gasoline, diesel or hybrid engine, comprising the use of a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity at 150° C. and under constant shear greater than or equal to 2.4 mPa.s−1.

[0081] The present invention further relates to a method for reducing the emission of particles in an engine, preferably a gas, gasoline, diesel or hybrid engine, lubricated by a lubricating composition comprising the addition of a base oil with a viscosity less than or equal to 4, to said lubricating composition.

[0082] The present invention further relates to a method for reducing the emission of particles in an engine, preferably a gas, gasoline, diesel or hybrid engine, lubricated by a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity, at 150° C. and under constant shear, greater than or equal to 2.4 mPa.s−1.

[0083] In such methods, the particles, the base oil and the lubricating composition are as defined hereinabove.

[0084] The present invention covers all motor vehicles, in particular vehicles comprising a 2-stroke or 4-stroke engine, gasoline, diesel, hybrid or gas engines.

[0085] The present invention covers all motor vehicles, preferably comprising at least one controlled ignition engine, preferably a combustion engine, in particular heavy vehicles or light vehicles, preferably heavy goods vehicles.

[0086] The present invention will now be described with the help of non-limiting examples.EXAMPLE 1Lubricating Compositions

[0087] The following lubricating compositions were prepared according to Table 2 below.TABLE 2Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)((in % with(in % with(in % with(in % with(in % with(in % withrespect torespect torespect torespect torespect torespect tothe totalthe totalthe totalthe totalthe totalthe totalweight of theweight of theweight of theweight of theweight of theweight of thecomposition)composition)composition)composition)composition)composition)Grade10W-4010W-405W-305W-300W-400W-30Additive21.411.321.411.321.421.4 packageMineral base76.184.57682.868.873.1oil (group III)(mixture oftwo baseoils)Base oil684432.9viscosityHydrogenated2.54.22.65.99.85.5styrenebutadienepolymer

[0088] The characteristics of the lubricating compositions are collated in Table 3 below:TABLE 3Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)KV 40° C.91.5794.3256.7652.4574.2250.3ASTMD445-97or ISO3104(mm2 / s)KV 100° C.13.4913.89.7479.75113.539.674ASTMD445-97or ISO 3104(mm2 / s)VI147149158174188181(ISO 3104)HTHS 150° C.43.863.142.993.833.85CEC L14-90(mPa · s)Noack 1 h6.54.612.213.631.532250° C.CEC L-040-93(%)EXAMPLE 2Measurement of the Number of Emitted Particles and of Fuel Eco

[0089] The compositions of example 1 were tested over the WHTC cycle and the quantity of particles having a size greater than or equal to 10 nm emitted at the end of each cycle was measured.

[0090] The engine tests were carried out on turbocharged straight-six engines. The tests were carried out at the same starting temperature of the engine. All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases ahead from the exhaust system but after the treatment systems. Thereby, the effects observed are indeed due solely to the use of the lubricating composition and not to any other criterion such as the temperature, the humidity, etc.

[0091] The particle size distribution was measured in parallel by a Cambustion differential mobility spectrometer (DMS500). Same uses a high voltage discharge for charging every particle proportionally to the surface thereof. The charged particles are introduced into a classification section with a strong radial electric field. Such field causes particles to drift through a flow inside a column, toward the electrometer detectors. The particles are detected at different distances in the column, depending on the aerodynamic resistance / Icharge ratio thereof. The outputs of the 22 electrometers are processed in real-time at 10 Hz, so as to provide spectral data and other measurements.

[0092] Fuel consumption was also measured and calculated by the following equation:Fuel⁢ consumption=Total⁢ mass⁢ of⁢ fuel⁢ injected [g]cycle [kWh]

[0093] The emissions of particles were calculated as follows:Emissions⁢ of⁢ particles=Total⁢ number⁢ of⁢ particles [#]cycle [kWh]

[0094] The results are given in Table 4 hereinbelow:TABLE 4Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)Fuel248249246249249245consumption(g / kWh)Emissions of5.75 × 10123.78 × 10122.52 × 10122.18 × 10121.72 × 10121.56 × 1012particles(number / kWh)

[0095] The results clearly show that the choice of the base oil according to the invention (viscosity less than or equal to 4) clearly reduces particle emission. The results also show that the choice of the base oil according to the invention has no impact on the consumption of fuel (Fuel Eco), thereby showing that a reduction in particle emissions is not synonymous with an improvement of Fuel Eco.EXAMPLE 31st Testing CampaignPreparation of Lubricating Compositions The lubricating compositions were prepared according to Table 5 hereinafter.TABLE 5Composition 6Composition 7Composition 8Composition 9Composition 10(comparative)(comparative)(reference oil)(invention)(invention)Grade0W120W200W200W200W20Package of1414141414additivesBase oilBOV 4Mixture ofBOV 4Mixture of 90%Mixture ofGroup IIIgroup III baseGroup IIIBOV 4 Group IIIgroup III baseBase oiloils: 43% BOVBase oilbase oil andoils: 70% BOV4 oil and 57%10% BOV 64 oil and 30%BOV 6Group IVBOV 3base oilPISH0.4044.45.6polymerPMA00000polymerComposition 11Composition 12Composition 13Composition 14(invention)(invention)(invention)(invention)Grade0W20XW30XW30XW30Package of14141414additivesBase oilBOV 3BOV 3BOV 4BOV 4Group IIIGroup IIIGroup IIIGroup IIIBase oilBase oilBase oilBase oilPISH712.510.20polymerPAMA00010.0polymer

[0096] The numbers in Table 5 correspond to percentages by weight with respect to the total weight of composition.

[0097] The characteristics of the lubricating compositions are given in Table 6 below:TABLE 6Compo. 6Compo. 7Compo. 8Compo. 9Compo. 10(comp.)(comp.)(reference oil)(invention)(invention)HTHS 1502.172.552.642.62.6(mPa · s−1)CEC L-036-90 orASTM D4683Base oil viscosity4.3245.5784.3244.3043.918(100° C.)ASTM D445-97(mm2 / s)Noack volatility10.77.711.110.815.2ASTM D5800 orCEC L-040-93Compo. 11Compo. 12Compo. 13(invention)(invention)(invention)HTHS 1503.493.523.42(mPa · s−1)CEC L-036-90 orASTM D4683Base oil viscosity3.3204.3244.324(100° C.)ASTM D445-97(mm2 / s)Noack volatility2110.711.4ASTM D5800 or CECL-040-93Measurement of the Number of Emitted Particles

[0098] The compositions of example 3 were subjected to the WLTC or RDE tests and the quantity of particles per kilometer traveled having a size greater than or equal to 10 nm emitted at the end of each cycle was measured. An EB2ADTS (PSA Peugeot Citroën) engine with a displacement of 1.2 I (maximum power of 60 KW) was used.

[0099] The engine tests were carried out on turbocharged straight-three engines. The tests were carried out at the same starting temperature of the engine (20° C.). All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases at the outlet of the turbocharger and upstream of the post-treatment system.

[0100] The particle number was measured using a Horiba MEXA2000-SPCS particle counter equipped with an overhead diluter. Each lubricating composition was tested 10 times on a WLTC cycle (with forced cooling at 20° C. at the beginning of each cycle). The first 3 cycles were deliberately discarded to allow the injection system to stabilize. The other 7 cycles were taken into account for the results. Particle numbers were expressed as average particle numbers (PN10 and PN23) per kilometer over the cycle considered.

[0101] The test campaign was thus carried out on an iso-additivation matrix.

[0102] The results are given in Tables 7 and 8 hereinafter, which relate to the WLTC and RDE cycles, respectively.

[0103] The test of a reference oil (composition 8) provides a framework for each test. The test results are expressed with respect to the result of the last reference oil passed.TABLE 7Change of the number of particles(PN10) in comparison with theWLTC cyclecomposition 8Composition 6+23%(comparative)Composition 7+34%(comparative)Composition 9 −8%(invention)Composition 10−18%(invention)Composition 11−46%(invention)Composition 12−28%(invention)Composition 13−26%(invention)TABLE 8Change of the number of particles(PN10) in comparison with theRDE cyclecomposition 8Composition 6 +5%(comparative)Composition 7+12%(comparative)Composition 9−11%(invention)Composition 10−17%(invention)Composition 11−24%(invention)Composition 12 −4%(invention)Composition 13−22%(invention)The results of Tables 7 and 8 demonstrate that the compositions used according to the invention effectively serve to reduce the number of particles with a size greater than or equal to 10 nm, over a WLTC or RDE cycle.

[0105] Tables 9 and 10 hereinafter summarize the results obtained on an RDE or WLTC cycle for composition 8 as regards the particles with a size of 10 nm. The results show the repeatability of the effect of decreasing the emission of PN10 particles.TABLE 9Tests12345678#PN10 per2.26 ×2.04 ×2.23 ×1.89 ×1.61 ×1.64 ×1.84 ×1.64 ×km traveled10121012101210121012101210121012over WLTCcycle#PN10 per4.88 ×4.34 ×4.32 ×4.17 ×3.57 ×3.52 ×3.75 ×3.63 ×km traveled10121012101210121012101210121012over RDEcycleTABLE 10Reference oilPN10PN10Composition 8WLTCRDEMean value1.88E123.97E12Standard deviation0.25E120.48E12Standard Deviation / mean13%12%Repeatability (IC95)0.69E121.34E12Repeatability / average37%34%EXAMPLE 42nd Testing CampaignA second testing campaign was carried out. Lubricants differ in viscosity grade but also in the composition of additives and of base oils. Table 11 shows the characteristics of the lubricating compositions which demonstrate an influence of the viscosity grade on the reduction of the PN10 number, independently of the composition:TABLE 11Compo. 14Compo. 15Compo. 16Compo. 9Compo. 17(Inv.)(inv.)(inv.)(inv.)(inv.)Grade0W200W200W200W200W30Package ofA (14%)A (14%)A (14%)A (14%)B (12%)additivesBase oilBOV 4BOV 4BOV 4Mixture ofMixture ofGroup IIIGroup IIIGroup III90% BOV 440% BOV 4Base oilBase oilBase oilGroup IIIGroup IIIbase oil andbase oil, 40% BOV10% BOV 64 Group IVGroup IVbase oil andbase oil20% BOV 5Group IIIbase oilPISH polymer44.444.43.2PMA polymer2.9HTHS 1502.632.612.642.63.03(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.8.3798.2478.2288.2919.840ASTM D445-97(mm2 / s)Compo. 18Compo. 19Compo. 20Compo. 21Compo. 22(inv.)(inv.)(inv.)(comp.)(comp.)Grade0W305W305W400W120W12Package ofC (13%%)D (15%)E (13.3%)F (13%)F (13%)additivesBase oilMixture ofMixture ofMixture ofMixture ofMixture of70% BOV 445% BOV 655% BOV 455% BOV 438% BOV 4Group IIIGroup IIIGroup IIIGroup IIIGroup IIIbase oil,base oil andbase oil andbase oil,base oil,10% BOV 455% BOV 645% BOV 817% BOV 334% BOV 3Group IVGroup IVGroup IVGroup IIIGroup IIIbase oil andbase oilbase oilbase oil andbase oil and20% BOV 528% BOV 328% BOV 3Group IIIGroup VGroup Vbase oilbase oilbase oilPISH polymer3.28.78.356PMA polymer2.70000HTHS 1503.013.503.782.112.11(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.9.89011.2814.545.9785.967ASTM D445-97(mm2 / s)Compo. 23Compo. 24(comp.)(comp.)Grade0W120W12Package of additivesG (13.5%)G (13.5%)Base oilBOV 4BOV 4Group IIIGroup IIIBase oilBase oilPISH polymer00PMA polymer00HTHS 1501.922.00(mPa · s−1)CEC L-036-90 orASTM D4683Viscosity at 100° C.5.4575.868ASTM D445-97 (mm2 / s)Table 12 hereinafter shows the results obtained over a WLTC cycle with regard to the particles with a size of 10 nm.TABLE 12Amount of particles perkilometer traveled with a sizegreater than or equal to 10 nmComposition 14 (invention)2.84E+12Composition 15 (invention)2.49E+12Composition 16 (invention)2.39E+12Composition 17 (invention)2.25E+12Composition 10 (invention)1.25E+12Composition 18 (invention)1.14E+12Composition 19 (invention)1.75E+12Composition 20 (invention)5.00E+11Composition 21 (comparative)3.79E+12Composition 22 (comparative)4.35E+12Composition 23 (comparative)4.18E+12Composition 24 (comparative)4.01E+12The results show that the use of a lubricating composition according to the invention reduces the quantity of particles with a size greater than or equal to 10 nm.

Examples

example 1

Lubricating Compositions

[0087]The following lubricating compositions were prepared according to Table 2 below.

TABLE 2Composition 2Composition 3Composition 4Composition 5ReferenceComposition 1(according to(according to(according to(according tocomposition(comparative)the invention)the invention)the invention)the invention)((in % with(in % with(in % with(in % with(in % with(in % withrespect torespect torespect torespect torespect torespect tothe totalthe totalthe totalthe totalthe totalthe totalweight of theweight of theweight of theweight of theweight of theweight of thecomposition)composition)composition)composition)composition)composition)Grade10W-4010W-405W-305W-300W-400W-30Additive21.411.321.411.321.421.4 packageMineral base76.184.57682.868.873.1oil (group III)(mixture oftwo baseoils)Base oil684432.9viscosityHydrogenated2.54.22.65.99.85.5styrenebutadienepolymer

[0088]The characteristics of the lubricating compositions are collated in Table 3 below:

TABLE 3Composition 2Composition 3...

example 2

Measurement of the Number of Emitted Particles and of Fuel Eco

[0089]The compositions of example 1 were tested over the WHTC cycle and the quantity of particles having a size greater than or equal to 10 nm emitted at the end of each cycle was measured.

[0090]The engine tests were carried out on turbocharged straight-six engines. The tests were carried out at the same starting temperature of the engine. All other test bench conditions were kept constant as well. Sampling for the exhaust gas measurements was carried out from raw exhaust gases ahead from the exhaust system but after the treatment systems. Thereby, the effects observed are indeed due solely to the use of the lubricating composition and not to any other criterion such as the temperature, the humidity, etc.

[0091]The particle size distribution was measured in parallel by a Cambustion differential mobility spectrometer (DMS500). Same uses a high voltage discharge for charging every particle proportionally to the surface there...

example 3

1st Testing Campaign

Preparation of Lubricating Compositions The lubricating compositions were prepared according to Table 5 hereinafter.

TABLE 5Composition 6Composition 7Composition 8Composition 9Composition 10(comparative)(comparative)(reference oil)(invention)(invention)Grade0W120W200W200W200W20Package of1414141414additivesBase oilBOV 4Mixture ofBOV 4Mixture of 90%Mixture ofGroup IIIgroup III baseGroup IIIBOV 4 Group IIIgroup III baseBase oiloils: 43% BOVBase oilbase oil andoils: 70% BOV4 oil and 57%10% BOV 64 oil and 30%BOV 6Group IVBOV 3base oilPISH0.4044.45.6polymerPMA00000polymerComposition 11Composition 12Composition 13Composition 14(invention)(invention)(invention)(invention)Grade0W20XW30XW30XW30Package of14141414additivesBase oilBOV 3BOV 3BOV 4BOV 4Group IIIGroup IIIGroup IIIGroup IIIBase oilBase oilBase oilBase oilPISH712.510.20polymerPAMA00010.0polymer

[0096]The numbers in Table 5 correspond to percentages by weight with respect to the total weight of composition.

[0097]The ...

Claims

1. A method for reducing the emissions of particles in an engine, comprising the lubrication of said engine with a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or said mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100°° C. as per the standard ASTM D445, of less than or equal to 4.5 mm2 / s.

2. The method according to claim 1, wherein the base oil or the mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100°° C., as per the standard ASTM D445, of less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity at 150° C. and under constant shear of greater than or equal to 2.4 mPa.s−1.

3. The method according to claim 1, wherein the viscosity index of the base oil or of the mixture of base oils is greater than or equal to 130.

4. The method according to claim 1, wherein the particles have a size less than or equal to 10 nm.

5. The method according to claim 1, wherein the kinematic viscosity, measured at 100° C., of the base oil or of the mixture of base oils is comprised between 1.5 and 4.5 mm2 / s.

6. The method according to claim 1, wherein the viscosity at 150° C., and under constant shear, of the lubricating composition ranges from 2.4 mPa.s−1 to 5 mPa.s−1.

7. The method according to claim 1, wherein the lubricating composition has a grade according to SAEJ300 classification of type XW-(Y) where X represents 0, 5 or 10 and Y represents an integer from 6 to 50.

8. The method according to claim 1, wherein the quantity of base oil of mixture of base oils used is comprised between 50% to 97% by weight with respect to the total weight of the lubricating composition.

9. The method according to claim 1, wherein the lubricating composition further comprises at least one additive improving the viscosity index, chosen from the group consisting of hydrogenated butylene and styrene polymers, ethylene propylene copolymers and polymethacrylate polymers.

10. The method according to claim 1, wherein the reduction of particle emissions relates to the cycle WLTC and / or the cycle RDE.

11. (canceled)12. (canceled)13. (canceled)14. (canceled)15. A method of reducing particulate emission in a controlled ignition internal combustion engine, comprising the use of a lubricating composition comprising a base oil or a mixture of base oils, wherein said base oil or mixture of base oils has a kinematic viscosity (BOV or base oil viscosity) measured at 100° C., as per the standard ASTM D445, of less than or equal to 4.5 mm2 / s, and wherein said lubricating composition has a viscosity at 150° C. and under constant shear, greater of equal to 2.4 mPa.s−1.

16. The method according to claim 15, wherein the lubricating composition has a viscosity at 150° C., and under constant shear, ranging from 2.4 mPa.s−1 to 5 mPa.s−1 and / or wherein the lubricating composition has a grade according to SAEJ300 classification of type XW-(Y) where X represents 0, 5 or 10 and Y represents an integer from 6 to 50.

17. The method according to claim 15, wherein the viscosity index of the base oil or of the mixture of base oils is greater than or equal to 130.

18. The method according to claim 15, wherein the kinematic viscosity, measured at 100° C., of the base oil or of the mixture of base oils is comprised between 1.5 and 4.5 mm2 / s.

19. The method according to claim 15, wherein the quantity of base oil of mixture of base oils used is comprised between 50% to 97% by weight with respect to the total weight of the lubricating composition.

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