Use of diesel fuel composition

Abstract

Use of a diesel fuel composition comprising at least (5) volume percent biodiesel to reduce deposit buildup in the exhaust gas recirculation (EGR) system of a compression-ignition internal combustion engine.

Description

[Technical Field]

[0001] The present invention relates to the use of a diesel fuel composition containing a biodiesel component to provide specific benefits in an exhaust gas recirculation (EGR) system in a compression ignition engine. In particular, the present invention relates to the use of a diesel fuel composition to reduce deposit accumulation in an exhaust gas recirculation system in a compression ignition engine. [Background technology]

[0002] Exhaust gas recirculation (EGR) is a NOx emission control technology applicable to a wide range of diesel engines, from light-load, medium-load, and heavy-load diesel engine systems to two-stroke low-speed marine engines. The configuration of an EGR system depends on the required EGR rate and other requirements for the specific application. Most EGR systems include the following main hardware components: one or more EGR control valves, one or more EGR coolers, piping, flanges, and gaskets.

[0003] EGR systems are known to be prone to contamination by deposits accumulating on various EGR hardware components. This is a problem specific to high-pressure EGR systems. The deposits that form within the system can cause increased NOx emissions and fuel consumption, and can cause system failure by clogging the EGR valve or, in severe cases, completely shutting down the system. While an oxidation catalyst and / or particulate filter can be installed before the EGR system to reduce hydrocarbons and particulates from exhaust gases that cause EGR fouling, this increases cost and complexity and is therefore not widely adopted by manufacturers. In the case of low-pressure EGR, the DPF is located between the engine and the low-pressure EGR system, so deposits do not pose such a problem in these configurations.

[0004] Therefore, it is desirable to first prevent the formation of deposits and to provide a fuel-based solution applicable to all EGR systems, regardless of the equipment adopted by the manufacturer.

[0005] Biodiesel in the form of fatty acid methyl esters (FAMEs) is the most commonly used renewable fuel source in compression-ignition (diesel) engines. FAMEs are typically derived from biological sources and are usually included to reduce the environmental impact of fuel production and consumption processes or to improve lubricity. Globally, levels of FAMEs in diesel fuels are trending upward, but this is being capped in some markets due to concerns about the sustainability of FAME source materials and engine / vehicle compatibility. [Overview of the project]

[0006] It was found here that by using a diesel fuel composition containing a certain amount of biodiesel components such as FAME, a remarkable and previously unrecognized reduction in EGR deposit accumulation can be achieved.

[0007] The present invention provides for the use of a diesel fuel composition containing 5 volume% or more of biodiesel to reduce the accumulation of deposits in the exhaust gas recirculation (EGR) system of a compression-ignition internal combustion engine.

[0008] According to another aspect of the present invention, a method is provided for reducing deposit accumulation in an exhaust gas recirculation (EGR) system of a compression-ignition internal combustion engine, comprising the step of introducing a diesel fuel composition containing 5 volume% or more of biodiesel into the engine.

[0009] It has been found that the use of a diesel fuel composition containing a certain amount of biodiesel components can reduce deposit accumulation in the EGR system of a compression-ignition internal combustion engine.

[0010] The use of a diesel fuel composition containing a certain amount of biodiesel components has been found to, firstly, prevent the formation of deposits in EGR systems, and to be applicable to all EGR systems, regardless of the equipment adopted by the manufacturer. [Brief explanation of the drawing]

[0011] [Figure 1] Table 2 below shows a graph of the EGR deposit material content results, where circles indicate individual test results and diamonds indicate the average results for each FAME fuel content level tested in Example 1. [Figure 2] Table 2 below shows a graph of the average EGR deposit material amounts for each FAME fuel content level tested in Example 1. [Figure 3] Table 2 below shows a graph of the average rate of decrease in EGR deposit material for each FAME level tested in Example 1 for B0. [Modes for carrying out the invention]

[0012] As used herein, the use of a diesel fuel composition containing 5 volume% or more of biodiesel is provided for reducing deposit accumulation in the exhaust gas recirculation (EGR) system of a compression-ignition internal combustion engine.

[0013] In the context of this aspect of the present invention, the term “reduce sediment accumulation” encompasses any degree of reduction in sediment accumulation. The reduction in sediment accumulation may be 5% or more, preferably 10% or more, more preferably 20% or more, even more preferably 50% or more, and particularly 70% or more, compared to the sediment accumulation in an EGR system caused by a similar fuel formulation that does not contain biodiesel components. As used herein, the term “reduce accumulation” also encompasses, firstly, the prevention of EGR sediment formation.

[0014] The present invention has been found to be particularly useful in the case of high-pressure EGR systems, since these systems are more prone to deposit accumulation than low-pressure EGR systems.

[0015] Furthermore, the present invention is contemplated to be used for the purpose of purifying existing EGR deposits formed with conventional diesel fuel.

[0016] The first essential component herein is the biodiesel component. Biodiesel fuel is a fuel derived from biological materials.

[0017] The biodiesel component is present in the diesel fuel composition herein at 5% v / v or more, preferably 10% v / v or more, more preferably in the range of 10% v / v to 50% v / v, even more preferably in the range of 10% v / v to 40% v / v, particularly at a level of 20% v / v to 40% v / v. In a particularly preferred embodiment of the present invention, the biodiesel component is present at a level in the range of 20% v / v to 30% v / v with respect to the total diesel fuel composition.

[0018] Suitable biodiesel fuels for use herein include any bio-derived oxygenates. There are processing routes for deriving various types of oxygenated additives from biological materials, including, but not limited to, esters such as alcohols, ketones, phenols, ethers, and alkyl esters including methyl esters and ethyl esters.

[0019] The preferred biodiesel component for use in this specification is fatty acid alkyl ester (FAAE). It is known to include fatty acid alkyl esters (FAAE), particularly fatty acid methyl esters (FAME), in diesel fuel compositions, but not in the context of reducing the accumulation of deposits in an EGR system. Examples of suitable FAAE include rapeseed methyl ester (RME), palm oil methyl ester (POME), soybean oil methyl ester, sunflower oil methyl ester, tallow methyl ester (TME), used cooking oil methyl ester (UCOME), and the like. FAAE are typically derivable from biological sources and are typically included to reduce the environmental impact of fuel production and consumption processes or to improve lubricity.

[0020] Among FAAE, the most commonly used ones in the context of diesel fuel are methyl esters and are already known as renewable diesel fuels (so-called "biodiesel" fuels). They contain long-chain carboxylic acid molecules (generally 10 to 22 carbon atoms in length) and each has an alcohol molecule attached at one end. Organically derived oils such as vegetable oils (including recycled vegetable oils) and animal fats (including fish oils) can be subjected to a transesterification process with an alcohol (typically a C1 - C5 alcohol) to form the corresponding monoalkylated fatty esters typically. This process is preferably catalyzed by either an acid or a base (e.g., the base KOH) to convert the triglycerides contained in the oil from their glycerol backbone to the fatty acid components of the oil. FAAE can also be prepared from used cooking oils and can be prepared by standard esterification from fatty acids.

[0021] In the present invention, FAAE may be any alkylated fatty acid or a mixture of fatty acids. The fatty acid components are preferably derived from a biological source, more preferably from a plant source. They may be saturated or unsaturated. They may be linear or branched, cyclic or polycyclic. Preferably, they have 6 to 30 carbon atoms, preferably 10 to 30, more preferably 10 to 22, 12 to 24, or 16 to 18 carbon atoms, including the acid group -CO2H. FAAE typically comprises a mixture of different fatty acid esters of different chain lengths, depending on its source.

[0022] The FAAE used in this invention is preferably derived from natural fatty oils, such as tall oil, rapeseed oil, coconut oil, or soybean oil.

[0023] FAAE is preferably a C1-C5 alkyl ester, more preferably a methyl, ethyl, propyl, (preferably isopropyl) or butyl ester, even more preferably a methyl or ethyl ester, particularly a methyl ester. In one embodiment herein, FAAE is selected from methyl esters of coconut oil (POME) and methyl esters of rapeseed oil (RME), and mixtures thereof.

[0024] Generally, it may be natural or synthetic, refined or unrefined ("crude").

[0025] FAAE may contain impurities or by-products as a result of the manufacturing process.

[0026] The FAAE preferably conforms to the specifications applicable to the rest of the fuel composition and / or the base fuel to which it is added, taking into account the intended use of the composition (e.g., in which geographical region and at what time). In particular, the FAAE preferably has a flash point higher than 101°C (IP34) and a fossil fuel content of 1.9 to 6.0 mm. 2 / second, preferably 3.5-5.0mm 2 Kinematic viscosity at 40°C (IP71) per second, 845-910 kg / m³ at 15°C. 3Preferably 860-900 kg / m 3 It has a density (IP365, EN ISO12185 or EN ISO3675), a water content of less than 500 ppm (IP386), a T95 of less than -360°C (measured according to IP123, the temperature at which 95% of the fuel has evaporated), an acid value of less than -0.8 mg KOH / g, preferably less than 0.5 mg KOH / g (IP139), and an iodine (I2) value of less than 125 grams, preferably less than 120 grams or less than 115 grams per 110 g of fuel (IP84). It also preferably contains less than 0.2% w / w of free methanol, less than 0.02% w / w of free glycerol, and more than 96.5% w / w of ester (by gas chromatography, GC, for example). In general, it may be preferable that the FAAE conforms to the European standard EN14214 for fatty methyl esters for use as diesel fuel.

[0027] Two or more FAAEs may be added to the diesel fuel composition according to the present invention, either separately or as a pre-prepared blend.

[0028] FAAEs are typically incorporated into diesel fuel compositions as a blend (i.e., a physical mixture), optionally together with one or more other fuel components (such as diesel base fuel), and optionally together with one or more fuel additives. It is preferable that FAAEs be incorporated into the diesel fuel composition before the composition is introduced into a diesel engine that will run on the fuel composition.

[0029] In addition to FAAE, paraffinic diesel fuel is a preferred fuel component for use in the diesel fuel compositions described herein. Suitable paraffinic diesel fuel for use in the present invention can be derived from any suitable source, as long as it is suitable for use in diesel fuel compositions.

[0030] Suitable paraffinic diesel fuels include, for example, diesel fuel derived from Fischer-Tropsch, diesel fuel derived from hydrotreated vegetable oil (HVO), and mixtures thereof.

[0031] The paraffinic diesel fuel preferred for use in this specification is Fischer-Tropsch diesel fuel. The paraffinic nature of Fischer-Tropsch diesel fuel means that diesel fuel compositions containing it have a higher cetane number compared to conventional diesel.

[0032] Fischer-Tropsch derived diesel is a preferred paraffinic diesel for use herein, but the term “paraffinic diesel” as used herein also includes paraffinic diesel derived from the hydrogenation (HVO) of vegetable oils. The HVO process is based on oil refining technology, which uses hydrogen to remove oxygen from triglyceride vegetable oil molecules, splitting the triglycerides into three separate chains to produce paraffinic hydrocarbons.

[0033] If present, paraffinic diesel fuel (i.e., Fischer-Tropsch diesel fuel, hydrogenated vegetable oil diesel fuel) preferably consists of at least 95% w / w, more preferably at least 98% w / w, even more preferably at least 99.5% w / w, and most preferably up to 100% w / w of paraffinic components, preferably iso and normal paraffins.

[0034] "Fischer-Tropsch derived" means that the fuel or base oil is a synthetic product of the Fischer-Tropsch condensation process or derived therefrom. The term "non-Fischer-Tropsch derived" may be interpreted accordingly. Fischer-Tropsch derived fuels are sometimes referred to as GTL (Gas-to-Liquid) fuels.

[0035] The Fischer-Tropsch reaction converts carbon monoxide and hydrogen into longer-chain, usually paraffinic, hydrocarbons, i.e., in the presence of a suitable catalyst, typically at high temperatures (e.g., 125-300°C, preferably 175-250°C) and / or high pressures (e.g., 5-100 bar, preferably 12-50 bar), resulting in n(CO+2H2)=(-CH2-). n Add +nH2O+ and heat. If desired, a hydrogen:carbon monoxide ratio other than 2:1 may be used.

[0036] Carbon monoxide and hydrogen themselves can be derived from organic or inorganic sources, natural or synthetic sources, typically natural gas or organically derived methane. More recently, pathways have been explored to derive this synthesis gas carbon monoxide from carbon dioxide in order to reap the benefits of greenhouse gases.

[0037] Diesel fuel, kerosene fuel, and base oil products can be obtained directly from the Fischer-Tropsch reaction, or indirectly from hydrogenated Fischer-Tropsch products, for example, by fractionation of Fischer-Tropsch synthesis products. Hydrogenation may involve hydrocracking (see, for example, British Patent No. 2077289 and European Patent No. 0147873) to adjust the boiling point range and / or hydroisomerization which can improve low-temperature fluidity by increasing the proportion of branched paraffins. European Patent No. 0583836 describes a two-step hydrogenation method in which the Fischer-Tropsch synthesis product is first subjected to hydroconversion under conditions that are substantially free from isomerization or hydrocracking (which hydrogenates olefins and oxygen-containing components), and then at least a portion of the resulting product is subjected to hydroconversion under conditions that undergo hydrocracking and isomerization to obtain a substantially paraffinic hydrocarbon fuel or oil. The desired diesel fuel fraction may then be isolated, for example, by distillation.

[0038] Other post-synthesis treatments, such as polymerization, alkylation, distillation, decomposition-decarboxylation, isomerization, and hydrogenation, may be used to modify the properties of the Fischer-Tropsch condensation product, for example, as described in U.S. Patent Nos. A-4125566 and A-4478955.

[0039] Typical catalysts for the Fischer-Tropsch synthesis of paraffinic hydrocarbons contain, as catalytically active components, metals from Group VIII of the periodic table, particularly ruthenium, iron, cobalt, or nickel. Suitable such catalysts are described, for example, in European Patent No. 0583836.

[0040] An example of a Fischer-Tropsch-based process is SMDS (Shell Middle Distillate Synthesis), described in van der Burgt et al.'s "The Shell Middle Distillate Synthesis Process" (see above). This process (sometimes also referred to as Shell "Gas-to-Liquids" or "GTL" technology) produces diesel-range products by converting synthesis gas (primarily methane) from natural gas into heavy long-chain hydrocarbon (paraffin) waxes, which can then be hydroconverted and fractionated to produce liquid transport fuels such as diesel and kerosene. Versions of the SMDS process that utilize a fixed-bed reactor for the catalytic conversion step are currently used at Pearl GTL in Bintulu, Malaysia and Ras Laffan, Qatar. Kerosene and (gas) oil prepared by the SMDS process are commercially available, for example, from Royal Dutch / Shell Group of Companies.

[0041] The Fischer-Tropsch process results in diesel fuel derived from Fischer-Tropsch that is essentially free of sulfur and nitrogen, or contains undetectable levels of them. Compounds containing these heteroatoms tend to act as poisons to the Fischer-Tropsch catalyst and are therefore removed from the synthesis gas feed. Furthermore, the process, as it is normally operated, produces no aromatic components, or substantially none.

[0042] For example, the aromatic content of Fischer-Tropsch diesel fuel, as measured by ASTM D4629, is typically less than 1% w / w, preferably less than 0.5% w / w, and more preferably less than 0.1% w / w.

[0043] Generally speaking, Fischer-Tropsch fuels have relatively low levels of polar components, particularly polar surfactants, compared to, for example, petroleum-derived fuels. This is thought to contribute to improved defoaming and de-fogging performance. Examples of such polar components include oxygen-containing additives, as well as sulfur and nitrogen-containing compounds. The low levels of sulfur in Fischer-Tropsch fuels generally indicate low levels of both oxygen-containing additives and nitrogen-containing compounds, because they are all removed by the same processing method.

[0044] Preferred Fischer-Tropsch-derived diesel fuels for use herein are liquid hydrocarbon middle distillate fuels having a distillation range similar to that of petroleum-derived diesel, typically in the range of 160°C to 400°C, preferably with a T95 of 360°C or less. Furthermore, Fischer-Tropsch-derived fuels tend to have lower levels of undesirable fuel components such as sulfur, nitrogen, and aromatics.

[0045] Preferred Fischer-Tropsch diesel fuel typically has a pH of 0.76–0.80, preferably 0.77–0.79, and more preferably 0.775–0.785 g / cm³ at 15°C. 3 It has a density (measured according to EN ISO12185).

[0046] The Fischer-Tropsch-derived middle distillate fuel preferred for use herein has a cetane number (ASTM D613) greater than 70, preferably 70 to 85, and most preferably 70 to 77.

[0047] The Fischer-Tropsch-derived middle distillate fuel preferred for use herein has a kinematic viscosity at 40 °C (measured in accordance with ASTM D445) in the range of 2.0 mm 2 / s to 5.0 mm 2 / s, preferably 2.5 mm 2 / s to 4.0 mm 2 / s.

[0048] The Fischer-Tropsch-derived middle distillate preferred for use herein has a sulfur content (ASTM D2622) of 5 ppmw (parts per million by weight) or less, preferably 2 ppmw or less.

[0049] The Fischer-Tropsch-derived middle distillate fuel preferred for use in the present invention is suitable for sale and is produced as a separate end product for use in applications that require specific properties of middle distillate fuel. In particular, as described above, it exhibits a distillation range that falls within the range typically associated with Fischer-Tropsch-derived middle distillate fuel.

[0050] The fuel composition used in the present invention may include a mixture of two or more Fischer-Tropsch-derived middle distillate fuels.

[0051] When present, the Fischer-Tropsch-derived component (i.e., Fischer-Tropsch-derived middle distillate) used herein preferably contains 3% w / w or less, more preferably 2% w / w or less, and even more preferably 1% w / w or less cycloalkanes (naphthenes) by weight of the Fischer-Tropsch-derived component.

[0052] If present, the Fischer-Tropsch derived component used herein (i.e., Fischer-Tropsch derived diesel fuel) preferably contains olefins at a rate of 1% w / w or less, more preferably 0.5% w / w or less, by weight of the Fischer-Tropsch derived component.

[0053] The diesel fuel compositions described herein for use in the present invention are particularly suitable for use as diesel fuel and can be used as winter-grade diesel fuel for Arctic applications due to their excellent low-temperature fluidity characteristics.

[0054] For example, a cloud point of -10°C or lower (EN23015) or a cold filter plugging point (CFPP) of -20°C or lower (measured by EN116) may be possible with the fuel compositions of this specification.

[0055] The diesel fuel compositions described herein may include a diesel base fuel in addition to the biodiesel fuel component.

[0056] The diesel-based fuel may be any petroleum-derived diesel suitable for use in internal combustion engines, such as petroleum-derived low-sulfur diesel containing less than 50 ppm of sulfur, for example, ultra-low sulfur diesel (ULSD) or zero-sulfur diesel (ZSD). Preferably, the low-sulfur diesel oil contains less than 10 ppm of sulfur.

[0057] The petroleum-derived low-sulfur diesel preferred for use in this invention is typically 0.78 to 0.865 g / cm³ at 15°C. 3 Preferably 0.80 to 0.845 g / cm³ 3 Density, cetane number of at least 51 (ASTM D613), and at 40°C, 1.5-4.5 mm 2 / second, preferably 2.0-4.0mm 2 / second, more preferably 2.2-3.7mm 2It has a kinematic viscosity of 1 / second (ASTM D445).

[0058] In one embodiment, the diesel-based fuel is conventional petroleum-derived diesel.

[0059] Generally speaking, in the context of the present invention, fuel additives may be added to the fuel composition.

[0060] The inventors have found that, from the viewpoint of reducing the accumulation of deposits in EGR systems, it is particularly advantageous to include a deposit control additive (DCA) package in the diesel fuel composition in addition to the biodiesel component.

[0061] Unless otherwise specified, the concentration of each such additive (active substance) in the fuel composition is preferably in the range of 75 to 300 ppmw, more preferably 5 to 1,000 ppmw, and more favorably 95 to 150 ppmw. Such additives may be added at various stages during the production of the fuel composition. Those added to the base fuel at the refinery may be selected from, for example, antistatic agents, pipeline resistance reducers, middle distillate flow improvers (MDFIs) (e.g., ethylene / vinyl acetate copolymer or acrylate / maleic anhydride copolymer), lubricity improvers, antioxidants, and wax settling inhibitors.

[0062] The fuel composition may contain DCA, which means an agent (preferably a surfactant) that can act to remove and / or prevent the accumulation of combustion-related deposits in the engine, particularly in the fuel injection system such as injector nozzles. Such materials are sometimes referred to as dispersant additives. When the fuel composition contains DCA, preferred concentrations are of the active cleaning agent in the range of 20 to 500 ppmw, more preferably 40 to 500 ppmw, most preferably 40 to 300 ppmw, or 100 to 300 ppmw or 150 to 300 ppmw, relative to the total fuel composition. DCA for diesel fuels is known and commercially available. Examples of suitable DCA additives include polyolefin-substituted succinimide or polyamine succinamide, e.g., polyisobutylene succinimide or polyisobutyleneamine succinamide, aliphatic amines, Mannich bases or amines, and polyolefin (e.g., polyisobutylene) maleic anhydride. Particularly preferred are polyolefin-substituted succinimides, such as polyisobutylene succinimide.

[0063] Other components that can be incorporated as fuel additives, for example, in combination with detergents, include lubricity enhancers, such as dehazing agents like alkoxylated phenol-formaldehyde polymers, defoamers (e.g., commercially available polyether-modified polysiloxanes), ignition enhancers (cetane enhancers) (e.g., 2-ethylhexyl nitrate (EHN), cyclohexyl nitrate, di-tert-butyl peroxide, and those disclosed in column 2, line 27 to column 3, line 21 of U.S. Patent No. 4,208,190), and rust inhibitors (e.g., propane-1,2-diol heptester of tetrapropenylsuccinate). Examples include polyhydric alcohol esters of succinic acid derivatives, wherein the succinic acid derivative has an unsubstituted or substituted aliphatic hydrocarbon group containing 20 to 500 carbon atoms on at least one of its α-carbon atoms (for example, pentaerythritol diester of polyisobutylene-substituted succinic acid), corrosion inhibitors, fragrances, wear-resistant additives, antioxidants (for example, phenols such as 2,6-di-tert-butylphenol, or phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine), metal deactivators, antistatic additives, and mixtures thereof.

[0064] The additives preferably contain an antifoaming agent, and more preferably contain them in combination with a rust inhibitor and / or corrosion inhibitor and / or lubricating additive.

[0065] In particular, when the fuel composition has a low sulfur content (e.g., 500 ppmw or less), it is especially preferable that a lubricity enhancer be included in the fuel composition. The lubricity enhancer is preferably present at a concentration of 50 to 1000 ppmw, more preferably 100 to 1000 ppmw, relative to the total fuel composition.

[0066] The concentration of any de-fogging agent (active substance) in the fuel composition is preferably in the range of 1 to 20 ppmw, more preferably 1 to 15 ppmw, even more preferably 1 to 10 ppmw, and advantageously 1 to 5 ppmw. The concentration of any ignition enhancer (active substance) present is preferably 600 ppmw or less, more preferably 500 ppmw or less, and conveniently 300 to 500 ppmw.

[0067] The present invention may be particularly applicable when the fuel composition is used or intended to be used in direct injection diesel engines, such as rotary pump, inline pump, unit pump, electronic unit injector or common rail type direct injection diesel engines, or indirect injection diesel engines. The fuel composition may be suitable for use in high-horsepower and / or low-horsepower diesel engines, as well as in engines designed for on-road or off-road use.

[0068] In order to be suitable for at least the above-mentioned applications, the diesel fuel composition of the present invention preferably has one or more of the following characteristics.

[0069] - 1.9mm at 40℃ 2 / second or more, more preferably 1.9 to 4.5 mm 2 Kinematic viscosity in the range of / second; - 800 kg / m 3 More preferably in the range of 800 to 860, and even more preferably in the range of 800 to 845 kg / m 3 density; - T95 (temperature below 360℃); - Cloud point in the range of 0°C to -13°C, more preferably -5°C to -8°C; - CFPP in the range of -8℃ to -30℃, more preferably -15℃ to -20℃.

[0070] The present invention will be further described with reference to the following non-limiting embodiments. [Examples]

[0071] Example 1 In the embodiments described herein, four different fuels were used.

[0072] One fuel was a conventional diesel fuel, CEC RF79-07 (Diesel B0). The physical properties of the conventional diesel fuel (Diesel B0) used in the examples are shown in Table 1 below. As used herein, "Diesel B0" refers to a diesel-based fuel containing zero biofuel components. The biofuel component was coconut oil methyl ester (POME).

[0073] The second, third, and fourth test fuels were diesel fuel compositions designed to contain 10%, 20%, or 30% biofuel components. In practice, with normal experimental error, the actual biofuel content of the fuels was 10.5%, 20.6%, and 29.9%, respectively. The base diesel fuel to which the biofuel was added was a diesel fuel conforming to the EN590 diesel fuel standard and is a reference fuel designated as CEC RF79-07. Here again, the biofuel component was a POME FAME component. The analyzed properties of the diesel and FAME blends B10, B20, and B30 fuels used in the examples are shown in Table 1 below.

[0074] [Table 1]

[0075] Test method The engine used in the example was a standard configuration PSA DV6 1.6L Euro5 engine of the type installed in several low-horsepower passenger car models in Europe. A clean EGR system was weighed and then installed in the engine.

[0076] The test was conducted continuously for 24 hours under test conditions of 2500 rpm and 5 kW (19 Nm). The engine coolant temperature was controlled to 37°C throughout the entire test period. Upon completion of the test, the engine was disassembled and all EGR components were weighed. Then, all EGR components were photographed, and subsequently, the entire EGR system was cleaned using a solvent and ultrasonic bath to remove deposits. Next, the cleaned EGR system was reweighed and reinstalled in the engine for the next test. A series of tests was performed designed to avoid consecutive repetitions for any fuel, with the exception of two tests on B0 at the start of the sequence, which were performed to ensure an acceptable level of repeatability. The remaining repetitions for each fuel were distributed throughout the test sequence to ensure a balanced test order. Four tests were performed using fuel B0, and two tests were performed for each of B10, B20, and B30. The test sequence and the results of the EGR deposit amounts are shown in Table 2 below, and the results are shown in Figures 1 to 3.

[0077] [Table 2]

[0078] Consideration As can be seen from the results in Table 2 and the graphs in Figures 1 to 3, compared to conventional diesel B0 fuel, the amount of deposits formed on the EGR components was significantly reduced in the case of FAME-containing fuel, and this reduction increased with increasing FAME levels. In the case of B10 diesel fuel, the amount of deposits formed on the EGR components was 22.0% less than that of B0 diesel fuel. In the case of B20 fuel, the difference from B0 was 27.2%, and in the case of B30 fuel, the difference from B0 was 28.8%. This specification encompasses the following embodiments of the invention. [Item 1] Use of a diesel fuel composition containing 5 volume% or more of biodiesel to reduce deposit accumulation in the exhaust gas recirculation (EGR) system of a compression-ignition internal combustion engine. [Item 2] The use according to item 1, wherein the diesel fuel composition contains 10% to 50% by volume of biodiesel relative to the diesel fuel composition. [Item 3] The use according to item 1 or 2, wherein the diesel fuel composition contains 20% to 40% by volume of biodiesel relative to the diesel fuel composition. [Item 4] The use of the biodiesel as described in any one of items 1 to 3, wherein the biodiesel is selected from fatty acid alkyl esters. [Item 5] The use described in any one of items 1 to 4, wherein the biodiesel is a fatty acid methyl ester. [Item 6] The use described in any one of items 1 to 5, wherein the biodiesel is rapeseed oil methyl ester (RME), coconut oil methyl ester (POME), soybean oil methyl ester, sunflower oil methyl ester, animal fat methyl ester (TME), used cooking oil methyl ester (UCOME), and mixtures thereof. [Item 7] The use according to any one of items 1 to 6, wherein the diesel fuel composition further comprises a deposit control additive (DCA) additive package. [Item 8] The use according to any one of items 1 to 7, wherein the diesel fuel composition further comprises a diesel base fuel. [Item 9] The use according to any one of items 1 to 8, wherein the diesel fuel composition further comprises a paraffinic base fuel selected from hydrogenated vegetable oil, Fischer-Tropsch-derived base fuel, and mixtures thereof. [Item 10] A method for reducing deposit accumulation in an exhaust gas recirculation (EGR) system of a compression ignition internal combustion engine, comprising the step of introducing a diesel fuel composition containing 5 volume% or more of biodiesel into the engine.

Claims

1. The use of a diesel fuel composition for reducing deposit accumulation in the exhaust gas recirculation (EGR) system of a compression ignition internal combustion engine, wherein the diesel fuel composition contains 20.6% to 50% by volume of biodiesel relative to the diesel fuel composition, wherein the biodiesel is coconut oil methyl ester (POME), and the diesel fuel composition further comprises a diesel base fuel.

2. The use according to claim 1, wherein the diesel fuel composition contains 20.6% to 40% by volume of biodiesel relative to the diesel fuel composition.

3. The use according to claim 1 or 2, wherein the diesel fuel composition further comprises a paraffin-based fuel selected from hydrogenated vegetable oil, Fischer-Tropsch-derived base fuel, and mixtures thereof.

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