Use of specific base oil to reduce particulate emissions

Abstract

Use of a specific base oil to reduce particulate emissions. This application relates to the use of a lubricating composition comprising a base oil or a base oil mixture having a viscosity (BOV or base oil viscosity) of 4 or less, to reduce particulate emissions from an engine. Figure for abstract: None

Description

Title of the invention: Use of a specific base oil to reduce particulate emissions

[0001] The present invention relates to the use of base oil of viscosity less than or equal to 4 to reduce particulate emissions from motor vehicles.

[0002] In 1993, the first European standard on emissions from internal combustion engine vehicles was introduced. Entering into force on September 1, 2014, for newly type-approved vehicles and applicable to all new vehicles from January 1, 2014, the Euro VI emissions standard (EC 595 / 2009) concerns heavy-duty vehicle engines. This standard specifically targets four pollutants: carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), and the mass (PM) and number (PN) of particulate matter, including soot, the latter two remaining the most problematic for the emissions control systems of modern engines.

[0003] The drive to reduce CO2 emissions has prompted manufacturers to increase efficiency in order to lower fuel consumption. To achieve this, they have often opted for lean-burn operation (excess air relative to the mass of fuel). Unfortunately, this process leads to a significant increase in nitrogen oxide and particulate emissions.

[0004] Manufacturers have also opted in the past to introduce particulate filter systems in an effort to reduce the number and mass of particles emitted into the atmosphere. In most cases, these systems operate by burning soot through a rise in the temperature of the exhaust gases at the filter inlet. This process requires a catalytic converter.

[0005] To comply with current and future standards, strict regulations on particle size, and in particular on the concentration of emitted particles (PN), are being established. Several studies have shown that, although the formation of particulate mass is low, the PN of particles emitted by compressed natural gas (CNG) engines is not negligible compared to that of diesel engines, particularly under high engine load conditions.

[0006] For this reason, the new Euro VI emission standards prescribe a limit of 6x10" particles per kWh, for heavy-duty Diesel and CNG vehicles.

[0007] The use of lubricating composition is considered to make an important contribution to the emission of small particles (less than 10 nm or 23 nm) emitted by this type of engine.

[0008] There is an interest in providing specifically adapted lubricating compositions to reduce the number of particles emitted from the exhaust of a vehicle, in particular a vehicle comprising at least one combustion engine, preferably a heavy goods vehicle.

[0009] An objective of the present invention is therefore to provide a suitable lubricating composition having a direct impact on particle emissions.

[0010] Another objective of the present invention is to provide a specific base oil enabling a lubricating composition to have a direct impact on particulate emissions.

[0011] Other objectives will become apparent upon reading the description of the invention which follows.

[0012] These objectives are met 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 viscosity of base oil) less than or equal to 4, to reduce particulate emissions from an engine.

[0013] In the context of the present invention, the term "particles" refers to particles emitted from the exhaust of motor vehicles. This represents a collection of microscopic particles (with a size on the order of µm or smaller). These substances are varied and are included in the exhaust gases of vehicles resulting from fuel combustion. These substances can be solid or liquid. The term "particles" includes soot, which forms, oxidizes, and contains unburned hydrocarbons, oxygenated derivatives (ketones, esters, aldehydes, lactones, ethers, organic acids), and polycyclic aromatic hydrocarbons (PAHs) along with their nitrated, oxygenated, and other derivatives. Mineral (SO2, sulfates, etc.) and metallic derivatives are also present.

[0014] In a particularly advantageous way, the present invention allows the reduction of emissions of particles having a size greater than or equal to 10 nm, for example greater than or equal to 23 nm.

[0015] In the context of the present invention, "particle size" means particles, or agglomerates of particles whose size is between 10 and 100 nm, for example between 10 and 100 nm, preferably between 10 and 60 nm, and preferably still between 10 and 40 nm, for example between 23 and 100 nm, preferably between 23 and 60 nm, and preferably still between 23 and 40 nm.

[0016] The size of the particles can in particular be measured by spectrometry, for example using a spectrometer manufactured by the company Cambustion under the commercial reference DMS500.

[0017] Reducing particle emissions means, in particular, reducing the number of particles, especially particles with a size greater than or equal to 10 nm, for example, greater than or equal to 23 nm. This includes, in particular, The reduction in the number of particles emitted during a WHTC regulatory cycle. This is measured based on the work done on the cycle (in # / kWh).

[0018] The number of particles can in particular be measured by a particle counting device such as the existing device under the commercial reference AVL APC 489.

[0019] Preferably, the present application relates to the reduction of soot emissions.

[0020] Preferably, the present invention relates to the reduction of emissions of particles, preferably particles of size greater than or equal to 10 nm, for example greater than or equal to 23 nm, preferably soot, over the entire regulatory cycle for heavy vehicle applications WHTC (World Harmonized Transient Cycle).

[0021] In the context of the present invention, the viscosity (also called BOV for base oil viscosity) is a kinematic viscosity and is measured at 100°C, according to ASTM D445.

[0022] In the context of a base oil mixture it must be understood that it is the viscosity of the base oil mixture that is less than or equal to 4.

[0023] Preferably, the base oil or base oil mixture has a viscosity between 1.5 and 4.

[0024] The lubricating composition 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 between 6 and 50, or between 8 and 40, preferably 12 or 30 or 40.

[0025] 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 their equivalents according to the ATIEL classification (Table 1) or their mixtures.

[0026] [Tables 1] Saturated Substances Content Sulfur Content Viscosity Index (VI) Group I Mineral Oils <90% > 0.03% 80 < VI < 120 Group II Hydrocracked Oils >90% < 0.03% 80 < VI < 120 Group III Hydroisomerized Oils >90% < 0.03% > 120 Group IV Polyalphaolefins (PAO) Group V Esters and other bases not included in Groups I to IV

[0027] The mineral base oils of the invention include any type of base oil obtained by atomospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0028] The base oils of the lubricating compositions according to the invention can also be chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, and polyalphaolefins. The polyalphaolefins used as base oils are, for example, obtained from monomers comprising 4 to 32 carbon atoms, for example from octene or decene, and for which the viscosity at 100°C is between 1.5 and 15 mm².sl according to ASTM D445.

[0029] The lubricating composition according to the invention may comprise at least 50% by weight of base oil relative 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 relative to the total weight of the lubricating composition. More preferably, 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 relative to the total weight of the composition.

[0030] The composition of the invention may also include at least one additive.

[0031] Many additives can be used in the lubricating compositions according to the invention.

[0032] The preferred additives for the lubricating composition according to the invention are chosen from detergent additives; the friction-modifying additives differ from molybdenum compounds as defined above, extreme pressure additives, dispersants, pour point activators, antifoaming agents, thickeners and mixtures thereof.

[0033] Preferably, the lubricating compositions according to the invention comprise at least one extreme pressure additive, or a mixture.

[0034] Anti-wear additives and extreme pressure additives protect surfaces from friction by forming a protective film adsorbed onto their surfaces.

[0035] There is a wide variety of anti-wear additives. Preferably, for the lubricating compositions of the invention, the anti-wear additives are chosen from among additives comprising phosphorus and sulfur, such as alkylthiophosphate metals, in particular zinc alkylthiophosphate, and more specifically zinc dialkyldithiophosphate or ZnDTP. The preferred compounds have the formula Zn((SP(S)(OR)(OR'))2, in which R and R', identical or different, independently represent an alkyl group, preferably an alkyl group comprising from 1 to 18 carbon atoms.

[0036] Amine phosphates are also anti-wear additives that can be used in the lubricating compositions of the invention. However, the phosphorus atoms provided by these additives can act as a poison for the catalytic converters of automobiles since they generate ash. It is possible to minimize these effects by substituting a portion of the amine phosphates with additives that do not provide phosphorus, such as, for example, polysulfides, in particular sulfur-containing olefins.

[0037] Advantageously, the lubricating compositions according to the invention can comprise from 0.01 to 6% by weight, preferably from 0.05 to 4% by weight, more preferably from 0.1 to 2% by weight relative to the total weight of lubricating composition, of anti-wear and extreme pressure additives.

[0038] Advantageously, the lubricating compositions according to the invention comprise from 0.01 to 6% by weight, preferably from 0.05 to 4% by weight, more preferably from 0.1 to 2% by weight relative to the total weight of the lubricating composition, of anti-wear additives (or anti-wear compound).

[0039] Advantageously, the compositions according to the invention may comprise at least one friction-modifying additive other than the molybdenum compounds of the invention. The friction-modifying additives may, in particular, be selected from compounds containing metallic elements and ash-free compounds. Among the compounds containing metallic elements, reference may be made to transition metal complexes such as Mo, Sb, Sn, Fe, Cu, and Zn, for which the ligands may be hydrocarbon compounds comprising oxygen, nitrogen, sulfur, or phosphorus atoms. The ash-free friction-modifying additives are generally of organic origin or may be selected from fatty acid and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, and epoxides. fatty acids, fatty epoxide borates, fatty amines or glycerol acid esters. According to the invention, fatty compounds comprising at least one hydrocarbon group comprising from 10 to 24 carbon atoms.

[0040] Advantageously the lubricating composition according to the invention may comprise from 0.01 to 2% by weight or from 0.01 to 5% by weight, preferably from 0.1 to 1.5% by weight or from 0.1 to 2% by weight relative to the total weight of the lubricating composition, of a friction modifying additive other than molybdenum compounds according to the invention.

[0041] Advantageously, the lubricating composition according to the invention may include at least one antioxidant additive.

[0042] Antioxidant additives generally delay the degradation of the lubricating composition. This degradation is most often expressed by the formation of deposits, the presence of sludge, or an increase in the viscosity of the lubricating composition.

[0043] Antioxidant additives generally act as radical scavenging agents or destructive hydroperoxide inhibitors. Commonly used antioxidants include phenolic antioxidants, amine antioxidants, and antioxidants containing sulfur and phosphorus. Some of these antioxidants, for example, those containing sulfur and phosphorus, can generate ash. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. Antioxidant additives may include, in particular, sterically hindered phenols, esters of sterically hindered phenols, sterically hindered phenols containing a thioether bridge, diphenylamines, diphenylamines substituted with at least one alkyl group at C12, N,N'-dialkylaryldiamines, and mixtures thereof.

[0044] Preferably according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group in 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 alkyl group in Cl to C10, preferably an alkyl group in Cl to C6, preferably an alkyl group in C4, preferably a ter-butyl group.

[0045] Amine compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example, aromatic amines of the formula NRaRbRc, in which Ra represents an aliphatic or aromatic group, optionally substituted, Rb represents an aromatic group, optionally substituted, and Rc represents a hydrogen atom, an alkyl group, an aryl group, or a group of the formula RdS(O)zRe, in which Rd represents an alkylene or alkenylene group, and Re represents a group alkyl, an alkenyl group or an aryl group and z represents 0, 1 or 2.

[0046] Alkyl-phenols containing sulfur or their alkali or alkaline earth metal salts can also be used as antioxidant additives.

[0047] Other classes of antioxidant additives are compounds comprising copper, for example copper thio- or dithio-phosphate, copper salts of carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonates. Copper I and II salts, succinic acid salts, or succinic anhydride salts may also be used.

[0048] Lubricating compositions according to the invention may also include any type of antioxidant known to those skilled in the art.

[0049] Advantageously, the lubricating composition includes at least one ash-free antioxidant additive.

[0050] Also advantageously, the lubricating composition according to the invention comprises from 0.1 to 2% by weight relative to the total weight of the composition, of at least one antioxidant additive.

[0051] The lubricating composition according to the invention may also include at least one detergent additive.

[0052] Detergent additives generally make it possible to reduce the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products.

[0053] The detergent additives that can be used in the lubricating compositions according to the invention are generally known to those 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 metallic cation of an alkali or alkaline earth metal.

[0054] Detergent additives are preferably selected from alkali or alkaline earth metal salts of carboxylic acid, sulfonates, salicylates, naphthenates, and phenate salts. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium, or barium.

[0055] These metal salts generally comprise the metal in stoichiometric quantities or in excess, that is, in a content greater than the stoichiometric content. These are then over-based detergents; the excess metal implying the over-based nature of the detergent additive is generally in the form of an oil-insoluble metal salt, for example carbonate, hydroxide, oxalate, acetate, glutamate, preferably carbonate.

[0056] Advantageously, the lubricating composition according to the invention can comprise from 0.5 to 8% or from 2 to 4% by weight of super-based detergent additives relative to the total weight of the lubricating composition.

[0057] Also advantageously, the lubricating composition according to the invention may also include a pour point lowering additive.

[0058] By slowing down the formation of paraffin crystals, the pour point lowering additive generally improves the cold behavior of the lubricating composition according to the invention.

[0059] As an example of pour point depressant additives, we can mention alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkyl-naphthalene, alkyl polystyrenes.

[0060] Advantageously, the lubricating composition according to the invention may also include a dispersing agent.

[0061] The dispersing agents can be chosen from Mannich bases, succinimides and their derivatives.

[0062] Also advantageously, the lubricating composition according to the invention can comprise from 0.2 to 10% by weight of dispersing agent relative to the total weight of lubricating composition.

[0063] Advantageously, the lubricating composition according to the invention may also further comprise at least one additional polymer that improves the viscosity index. Examples of additional polymers that improve the viscosity index include polymeric esters, homopolymers or copolymers, hydrogenated or non-hydrogenated, of styrene, butadiene, and isoprene, and polymethacrylates (PMAs). Also advantageously, the lubricating composition according to the invention may comprise from 1 to 15% by weight relative to the total weight of the lubricating composition of an additive that improves the viscosity index.

[0064] The lubricating composition according to the invention may also include at least one thickening agent.

[0065] The lubricating composition according to the invention may also include an antifoaming agent and a demulsifying agent.

[0066] The present invention also relates to the use of a base oil of viscosity less than or equal to 4 in a lubricating composition for an engine to reduce particulate emissions from said engine.

[0067] The present invention also relates to a method for reducing particle emissions in an engine, preferably a gas, petrol, diesel or hybrid engine, comprising the use of a lubricating composition comprising a base oil of viscosity less than or equal to 4.

[0068] The present invention also relates to a method of reducing particle emission in an engine, preferably a gas, petrol, diesel or hybrid engine, lubricated by a lubricating composition comprising the addition in said lubricating composition of a base oil of viscosity less than or equal to 4.

[0069] The particles, base oil and lubricating composition being as defined above.

[0070] The present invention covers all motorized vehicles, in particular vehicles comprising a 2-stroke or 4-stroke engine, petrol, diesel, hybrid, gas engines.

[0071] The present invention covers all motorized vehicles, preferably comprising at least one combustion engine, in particular heavy vehicles or light vehicles, preferably heavy goods vehicles.

[0072] The present invention will now be described using non-limiting examples. Example 1: Lubricating compositions

[0073] The following lubricating compositions were prepared according to the following table 2.

[0074] [Tables2] Reference composition (as a percentage of the total weight of the composition) Composition 1 (comparative) (as a percentage of the total weight of the composition) Composition 2 (according to the invention) (as a percentage of the total weight of the composition) Composition 3 (according to the invention) (as a percentage of the total weight of the composition) Composition 4 (according to the invention) (as a percentage of the total weight of the composition) Composition 5 (according to the invention) (as a percentage of the total weight of the composition) Grade 10W-40 10W-40 5W-30 5W-30 0W-40 0W-30 Additive package 21.4 11.3 21.4 11.3 21.4 21.4 Mineral base oil (Group III) 76.1 84.5 76 82.8 68.8 73.1 (mixture of two base oils) Base oil viscosity 6 8 4 4 3 2.9 Hydrogenated styrene butadiene polymer 2.5 4.2 2.6 5.9 9.8 5.5

[0075] The characteristics of the lubricating compositions are summarized in Table 3 below:

[0076] [Tables3] Reference composition Composition 1 (comparative) Composition 2 (according to the invention) Composition 3 (according to the invention) Compositi on 4 (according to the inventio n) Composition 5 (according to the invention) KV 40°C ASTM D445-97 or ISO3104 (mm2 / s) 91.57 94.32 56.76 52.45 74.22 50.3 KV 100°C ASTM D445-97 or ISO 3104 (mm2 / s) 13.49 13.8 9.747 9.751 13.53 9.674 VI (ISO 3104) 147 149 158 174 188 181 HTHS 150°C CEC L14-90 (mPa.s) 4 3.86 3.14 2.99 3.83 3.85 Noack Ih 250°C CEC L-040-93 (%) 6.5 4.6 12.2 13.6 31.5 32

[0077] Example 2: Measurement of the number of particles emitted and the Fuel Eco

[0078] The compositions of Example 1 were tested on WHTC cycle and the quantity of particles with a size greater than or equal to 10 nm emitted at the end of each cycle was measured.

[0079] The engine tests were carried out on turbocharged inline 6-cylinder engines. The tests were performed at the same engine starting temperature. All other test bench conditions were also kept constant. Sampling for exhaust gas measurements was carried out on the raw exhaust gases before the exhaust system but after the systems of treatment. Thus, the observed effects are due solely to the use of the lubricating composition and not to any other criterion such as temperature, humidity, etc.

[0080] The particle size distribution was measured in parallel using a Cambustion Differential Mobility Spectrometer (DMS500). This spectrometer uses a high-voltage discharge to charge each particle proportionally to its surface area. The charged particles are introduced into a classification section with a strong radial electric field. This field causes the particles to drift through a flow in a column towards the electrometer detectors. The particles are detected at different distances in the column, depending on their aerodynamic drag-to-charge ratio. The outputs of the 22 electrometers are processed in real time at 10 Hz to provide spectral data and other measurements.

[0081] Fuel consumption was also measured and calculated using the following equation: F00821 z-> / i Total mass of fuel injected [a] Fuel consumption ----------—----— cycle [kwn]

[0083] Particle emissions are calculated as follows: F00841 t- j .• > total number of particles [#] iwoti Particle emissions -------<-ÿëïê"ikwüj----“

[0085] The results are given in Table 4 below:

[0086] [Tables4] Reference composition Composition 1 (comparative) Composition 2 (according to the invention) Composition 3 (according to the invention) Composition 4 (according to the invention) Composition 5 (according to the invention) Fuel consumption (g / kWh) 248 249 246 249 249 245 Particulate emissions (number / kWh) 5.75 x 10¹² 3.78 x 10¹² 2.52 x 10¹² 2.18 x 10¹² 1.72 x 10¹² 1.56 x 10¹²

[0087] These results clearly show that the choice of base oil according to the invention (viscosity less than or equal to 4) allows for a significant reduction in particulate emissions. These results also show that the choice of base oil according to the invention has no impact on fuel consumption (Fuel Eco), thus demonstrating that a reduction in particulate emissions is not synonymous with an improvement in fuel efficiency. Fuel Eco link.

Claims

Demands

1. Use of a lubricating composition comprising a base oil or base oil mixture having a kinematic viscosity (BOV or base oil viscosity) measured at 100°C, according to ASTM D445, of 4 or less, to reduce particulate emissions from an engine.

2. Use of a base oil of viscosity less than or equal to 4 in an engine lubricant composition to reduce particulate emissions from said engine.

3. Method for reducing particulate emissions in an engine, preferably a gas, petrol, diesel or hybrid engine, comprising the use of a lubricating composition comprising a base oil of viscosity less than or equal to 4.

4. A method for reducing particulate emissions in an engine, preferably a gas, gasoline, diesel, or hybrid engine, lubricated by a lubricating composition comprising the addition to said lubricating composition of a base oil of viscosity less than or equal to A

5. Use according to claim 1 or 2 or method according to claim 3 or 4, wherein the base oil has a viscosity between 1.5 and 4.

6. Use according to claim 1, 2 or 5 or method according to claim 3, 4 or 5, wherein the lubricating composition has a grade according to the SAEJ300 classification of type XW-(Y) with X representing 0, 5 or 10 and Y representing an integer between 8 and 40, preferably 30 or 40.

7. Use according to claim 1, 2, 5 or 6 or method according to claim 3, 4, 5 or 6 wherein the amount of base oil is between 50 and 97% by weight relative to the total weight of the lubricating composition.

8. Use according to claim 1, 2, 5, 6 or 7 or method according to claim 3, 4, 5, 6 or 7 wherein the lubricating composition further comprises a hydrogenated butylene and styrene polymer.

9. Use according to any one of claims 1, 2, 5 to 8 or method according to any one of claims 3, to 8, wherein the particles have a size greater than or equal to 10 nm.

10. Use according to any one of claims 1, 2, 5 to 9 or method according to any one of claims 3 to 9 wherein the reduction of particulate emissions relates to the WHTC cycle.