Fuel compositions rich in aromatic compounds, paraffins and ethanol and their use, in particular in racing car vehicles

Abstract

The invention relates to a fuel composition comprising: (i) 60 to 94 mass% of a hydrocarbon mixture comprising: (a) 35 to 55 mass% of aromatic compounds; (b) 30 to 50 mass% of a mixture of n-paraffins and isoparaffins containing at least 5 carbon atoms, wherein the ratio of the amount of isoparaffins to the amount of n-paraffins is greater than or equal to 3; and (c) 5 to 15 mass% of cycloparaffins; (ii) 5 to 36 mass% of ethanol; and (iii) 1 to 10 mass% of butane. The composition can be used to fuel a spark-ignition engine in a motor vehicle intended for use by the general public or in a competition.

Description

[0001] An object of the present application is a fuel composition intended for vehicles comprising a spark ignition engine (or gasoline engine) and having advantageous properties.

[0002] Another object of the present application is the use of such a composition to fuel a spark ignition engine in a conventional vehicle, in particular an automotive vehicle, and in a racing car.

[0003] Gasoline-type fuels that can be used in spark ignition engines, in particular those in automotive vehicles, should have a sufficiently high octane number to avoid the phenomenon of knock.

[0004] It is known that the octane number measures the resistance to auto-ignition (auto-ignition) of a fuel used in a spark ignition engine.

[0005] Generally, gasoline fuels sold in Europe have a motor octane number (MON) greater than 85 and a research octane number (RON) of at least 95, according to the standard EN 228. These fuels are suitable for the vast majority of automotive engines.

[0006] To increase their efficiency, modern spark ignition engines tend to be operated with increasingly high compression ratios, i.e. a high compression ratio is applied to the fuel / air mixture in the engine before it is ignited.

[0007] However, increasing the volumetric compression ratio in the engine increases the risk of abnormal combustion of the type of knock caused by the local auto-ignition of the fuel mixture upstream of the flame front. This phenomenon generates a characteristic noise and is liable to damage the engine.

[0008] For very high-power engines, such as those used in racing cars, a high compression volumetric ratio is particularly desirable.

[0009] For this type of engine, it is therefore necessary to use a fuel that is highly resistant to knock and pre-ignition, leading to a fuel with as high a "research" octane number (RON) as possible. If the octane number is insufficient, the phenomenon of knock or auto-ignition of the fuel can occur, which can significantly reduce engine performance and even cause serious damage to the engine.

[0010] In addition, for all vehicles and in particular those intended for general public use, there is a growing trend to use fuels formulated from plant-based bases and in particular so-called "bio-sourced" bases, in order to respond to environmental problems and limit the use of fossil resources. The current environmental problems prompt consumers to seek more environmentally friendly fuels.

[0011] However, the use of fuel compositions based on matrices of biological origin should not impair the fuel properties, and in particular the octane number and the engine power, which should be maintained or even increased.

[0012] The most commonly used gasoline fuels with a high content of biological compounds are those containing bioethanol, such as E85, E10 and E5. However, the use of these fuels represents only a small part of the current car market.

[0013] Bioethanol is known to be mixed with gasoline fuels of the SP95 type. The ethanol content is then limited to a maximum of 10% by volume in order to comply with the specifications of standard EN 228, in particular those relating to the incorporation of oxygenated compounds.

[0014] There is therefore a need to develop new fuel compositions for providing fuel for spark-ignition engines meeting the requirements of modern vehicles, whether they are intended for general public applications (light vehicles, heavy goods vehicles, off-road vehicles, etc.) or for competition.

[0015] There is therefore a need for fuels for spark-ignition internal combustion engines, which have a high octane number, and in particular a high RON, and which make it possible to maximize the engine power of car vehicles, in particular racing cars, operating at high volumetric compression ratios.

[0016] It is therefore an object of the present application to improve the performance of gasoline fuel compositions, in particular but not only fuel compositions intended for racing cars. It is an object to increase the energy content of the fuel, which will result in an increase in the power of the spark-ignition engine during the combustion of the gasoline fuel composition in the engine, whether atmospheric or turbocharged.

[0017] There is also an increasing need to be able to formulate such compositions from matrices and / or compounds of renewable origin, also called biological origin.

[0018] As is well known in the prior art, octane (value) booster additives are generally added to gasoline-type fuel compositions. Organic metal compounds containing in particular iron, lead or manganese are well known octane number boosters.

[0019] Thus, tetraethyl lead (TEL) has been widely used as a very effective octane number booster. However, in most regions of the world, TEL and other organic metal compounds can now only be used in very small amounts, if at all, in fuels, because they can be toxic, cause engine damage and are harmful to the environment.

[0020] Non-metal based octane enhancers include oxygenates (e.g. ethers and alcohols) and aromatic amines. However, these additives also suffer from various drawbacks. For example, N-methylaniline (NMA), which is an aromatic amine, should be used at a relatively high treat rate (1.5 to 2 wt% of additive / fuel base weight) to have a significant effect on the octane rating of the fuel. NMA can also be toxic.

[0021] By way of example, document US-A-4812146 describes unleaded gasoline fuel compositions for engines used in racing, which comprise at least four components chosen from butane, isopentane, toluene, MTBE (methyl tertiary butyl ether) and alkylate.

[0022] Document WO2010 / 014501 describes unleaded gasoline fuel compositions comprising: at least 45% by volume of branched paraffins, at most 34% by volume of one or more mono- and di-alkylated benzenes, from 5 to 6% by volume of at least one linear paraffin having from 3 to 5 carbon atoms (denoted C3-C5), in an amount sufficient to increase the AKI (anti-knock index) which is (RON+MON) / 2, to at least 93, of one or more alkanols having from 2 to 4 carbon atoms (denoted C2-C4). These compositions are presented as having high torque and maximum power.

[0023] Thus, there is a search for fuel compositions having good intrinsic properties, i.e. not necessarily requiring the addition of octane enhancers such as those described above.

[0024] Continuing its research into the development of fuel formulations for gasoline engines, the Applicant has now found compositions which make it possible to meet the above-mentioned objectives.

[0025] Thus, one object of the present application is a fuel composition comprising

[0026] (i) from 60 to 94% by weight of a hydrocarbon mixture comprising:

[0027] a) from 35 to 55% by weight of aromatic compounds;

[0028] b) from 30 to 50% by weight of a mixture of n-paraffins and iso-paraffins containing at least 5 carbon atoms, in which the weight ratio of the amount of iso-paraffins to the amount of n-paraffins is greater than or equal to 3; and

[0029] c) from 5 to 15% by weight of naphthenes;

[0030] (ii) from 5 to 36% by weight of ethanol; and

[0031] (iii) from 1 to 10% by weight of butane.

[0032] These compositions are intended to be used for providing fuel in a spark-ignition engine (or gasoline engine).

[0033] The fuel composition according to the application has a high RON (Research Octane Number) octane number.

[0034] In applications in which the fuel flow rate is limited, especially in the case of racing cars, the use of the composition according to the application makes it possible to achieve a higher level of engine power at constant fuel flow rate.

[0035] In particular, it has been shown that formulating compositions with said compounds and in the specific proportions defined above makes it possible to obtain synergistic performances in terms of RON octane number and engine power.

[0036] These properties are particularly sought after for use in racing cars.

[0037] The composition according to the application also offers significant advantages for uses other than in racing cars, such as so-called general public (public) uses, especially for light vehicles (or LV). If necessary, it can meet the specifications of standard EN 228.

[0038] The composition according to the application can advantageously be prepared, in whole or in part, from matrices and / or compounds of plant origin. In particular, the composition according to the application can contain at least 50% by weight of one or more matrices of biological origin, preferably at least 60% by weight, and even more preferentially at least 75% by weight of one or more matrices of biological origin.

[0039] Another object of the application is the use of the composition according to the application for providing fuel for a spark-ignition engine.

[0040] According to one particular embodiment, the composition according to the application is used as fuel for high-performance, high-power spark-ignition engines, preferably racing car engines.

[0041] Other objects, characteristics, aspects and advantages of the application will become even more clearly apparent on reading the description which follows and the examples.

[0042] Hereinafter, and unless otherwise stated, the limits of a range of values are included in the range, especially in the expressions: "between... and...", "in the range of... to...", and "from... to...".

[0043] Furthermore, the expressions "at least one (kind)" and "at least" used in the present description are respectively equivalent to the expressions "one or more (kind)" and "greater than or equal to".

[0044] Finally, in a manner known per se, C NA compound is a compound containing N carbon atoms in its chemical structure, and C N+ A compound is a compound containing at least N carbon atoms.

[0045] Fuel composition

[0046] The composition according to the application comprises a mixture (i) of hydrocarbons comprising:

[0047] a) from 35 to 55% by weight of aromatic compounds;

[0048] b) from 30 to 50% by weight of a mixture of n-paraffins and isoparaffins containing at least 5 carbon atoms, the weight ratio of the amount of isoparaffins to the amount of n-paraffins being greater than or equal to 3; and

[0049] c) from 5 to 15% by weight of cycloparaffins.

[0050] These contents are expressed by weight relative to the weight of the mixture of hydrocarbons (i).

[0051] Such a mixture of hydrocarbons represents from 60 to 94% by weight relative to the total weight of the fuel composition, preferably from 65 to 90% by weight relative to the total weight of the fuel composition, more preferentially from 70 to 85% by weight, even more preferentially from 70 to 80% by weight.

[0052] The aromatic compound(s) (i) a) are preferably chosen from alkylbenzenes containing from 7 to 12 carbon atoms. By alkylbenzene, it is meant, in a manner known per se, a benzene derivative in which one or more hydrogen atoms have been replaced by one or more alkyl groups.

[0053] The aromatic compound(s) can in particular be chosen from toluene, ethylbenzene, xylenes (and notably 1,2-dimethylbenzene or o-xylene, 1,3-dimethylbenzene or m-xylene and 1,4-dimethylbenzene or p-xylene), 1 -ethyl-3-methylbenzene, mesitylene (1,3,5-trimethylbenzene), 1 -ethyl-3,5-dimethylbenzene and mixtures of these compounds.

[0054] Particular preference is given to mixtures of aromatic compounds, and more particularly mixtures of alkylbenzenes containing from 8 to 10 carbon atoms, such as ethylbenzene, xylenes (and notably 1,2-dimethylbenzene or o-xylene, 1,3-dimethylbenzene or m-xylene, and 1,4-dimethylbenzene or p-xylene), 1 -ethyl-3-methylbenzene, mesitylene (1,3,5-trimethylbenzene) and 1 -ethyl-3,5-dimethylbenzene.

[0055] Preferably, the content of aromatic compounds (i) a) ranges from 40 to 53% by weight, preferably from 45 to 52% by weight, relative to the weight of the hydrocarbon mixture (i).

[0056] The composition according to the application further comprises paraffins (i) b) containing at least 5 carbon atoms. These paraffins are acyclic and consist of a mixture of n-paraffins and iso-paraffins.

[0057] By "paraffins", in a manner known per se, is meant branched alkanes (also called iso-paraffins or isoparaffins) and unbranched alkanes (also called n-paraffins or normal alkanes).

[0058] The paraffins are preferably chosen from those containing from 5 to 12 carbon atoms, more preferentially from 5 to 9 carbon atoms and even more preferentially from 5 to 8 carbon atoms.

[0059] The paraffins include n-paraffins (or n-alkanes, i.e. linear alkanes) and iso-paraffins (i.e. branched alkanes).

[0060] A mixture of n-paraffins and iso-paraffins chosen from those described above is used, comprising a major proportion of iso-paraffins, in which the weight ratio of the amount of iso-paraffins to the amount of n-paraffins is greater than or equal to 3, preferably greater than or equal to 4 and better still ranges from 4 to 5.

[0061] The hydrocarbon mixture (i) advantageously contains from 5 to 10% by weight of n-paraffins and from 20 to 45% by weight of iso-paraffins.

[0062] Preferably, the content of paraffins (i) b) ranges from 32 to 45% by weight, more preferentially from 35 to 42% by weight, relative to the weight of the hydrocarbon mixture (i).

[0063] The composition according to the application further contains cycloparaffins (i) c).

[0064] By "cycloparaffins", in a manner known per se, is meant cyclic alkanes (or cycloalkanes) containing from 5 to 10 carbon atoms. Preferentially, the cycloparaffins are chosen from cyclic alkanes containing from 5 to 10 carbon atoms and more preferentially from 6 to 9 carbon atoms.

[0065] Preferably, the content of cycloparaffins (i) c) ranges from 7 to 13% by weight, more preferentially from 8 to 12% by weight, relative to the weight of the hydrocarbon mixture (i).

[0066] According to a preferred embodiment, the hydrocarbon mixture (i) is derived from a plant raw material. Thus, the mixture (i) advantageously consists entirely of hydrocarbons of biological origin. For example, the raw plant material can be chosen from cereals (wheat, corn), rapeseed, sunflower, soybean, palm oil, sugar cane, sugar beet, wood waste, straw (straw, straw), sugar cane residue, wine residues, used cooking vegetable oil, algae and lignocellulosic materials.

[0067] The composition according to the application also contains ethanol.

[0068] According to a preferred embodiment, ethanol of plant origin, also called bioethanol, is used.

[0069] For example, bioethanol can be produced from the fermentation of sugars, mainly glucose, using traditional or genetically modified yeast strains. Different plant raw materials can be used to produce bioethanol, such as sugar cane, corn, barley, potato waste, sugar beet and wine residues such as wine lees.

[0070] The ethanol content of the composition ranges from 5 to 36% by weight, preferably from 10 to 30% by weight and even more preferentially from 20 to 25% by weight, relative to the total weight of the fuel composition.

[0071] The composition according to the application also contains butane, which can be chosen from n-butane (linear butane), isobutane (2-methylpropane) and mixtures of these two compounds.

[0072] Preferentially, a mixture of n-butane and isobutane is used.

[0073] The butane content of the composition ranges from 1 to 10% by weight, preferably from 1.5 to 8% by weight and better still from 2 to 6% by weight, relative to the total weight of the fuel composition.

[0074] According to a preferred embodiment, the composition according to the application contains at most 2.5% by weight of olefins, preferentially at most 2% by weight of olefins, more preferentially at most 1% by weight of olefins, better still at most 0.5% by weight of olefins.

[0075] The research octane number (RON value) of the composition as described above is generally greater than or equal to 95, preferentially greater than or equal to 99 and more preferentially greater than or equal to 100, the RON being measured according to the standard ASTM D 2699-86.

[0076] The values mentioned above relate to the intrinsic octane number of the composition, i.e. without the addition of additional compounds such as, in particular, octane-boosting additive additives.

[0077] In addition to the above-mentioned base compounds, the fuel composition according to the application can also comprise one or more additives chosen from those additives which are frequently used in gasoline fuels.

[0078] In particular, the composition according to the application can comprise at least one detergent additive ensuring the cleanliness of the intake circuit. Such an additive can be chosen, for example, from succinimides, optionally substituted with polyisobutylene groups, polyether amines, betaines, Mannich bases and quaternary ammonium salts, such as those described in documents US 4 171 959 and WO 2006 135 881.

[0079] The composition can also comprise at least one lubricity additive or anti-wear agent, chosen in particular (but not exclusively) from fatty acids and ester or amide derivatives thereof, in particular glycerol monooleate, and monocyclic and polycyclic carboxylic acid derivatives. Examples of such additives are given in documents EP 680 506, EP 860 494, WO 98 / 04656, EP 915 944, FR 2 772 783, FR 2 772 784.

[0080] Other additives can also be incorporated into the fuel composition according to the application, such as anti-valve recession additives and antioxidant additives.

[0081] For each of them, the above-mentioned additives can be added to the fuel composition in an amount ranging from 10 to 1000 ppm by weight, preferably from 100 to 500 ppm by weight.

[0082] According to one preferred embodiment, the composition comprises an additive package, that is to say a combination of at least two different additives, advantageously chosen from detergent additives, lubricity additives, anti-valve recession additives and antioxidant additives. These additives are advantageously chosen from those mentioned above.

[0083] The fuel compositions according to the application have a lead content (for example in the form of tetraethyl lead) generally less than or equal to 5 mg / L, and are preferably unleaded, that is to say they do not contain lead or lead compounds.

[0084] Preparation of a fuel composition

[0085] The composition according to the application can be prepared by simply mixing its constituents.

[0086] The first non-limiting embodiment comprises the following steps:

[0087] 1 ) preparing a hydrocarbon mixture (i) comprising from 35 to 55 wt% of aromatic compounds; from 30 to 50 wt% of a mixture of n-paraffins and iso-paraffins containing at least 5 carbon atoms, wherein the weight ratio of the amount of iso-paraffins to the amount of n-paraffins is greater than or equal to 3; and from 5 to 15 wt% of naphthenes; then

[0088] 2) mixing 60 to 94 wt% of said mixture (i) with 5 to 36 wt% of ethanol and 1 to 10 wt% of butane.

[0089] A second non-limiting embodiment comprises the following steps:

[0090] 1 ') preparing a matrix B comprising a hydrocarbon mixture (i) and butane; then

[0091] 2') mixing said matrix B with ethanol so that the content of ethanol in the final composition is in the range from 5 to 36 wt%; and

[0092] 3') optionally, adding butane so that the amount of butane in the final mixture is in the range from 1 to 10 wt%.

[0093] A preferred alternative of this second embodiment comprises the following steps:

[0094] 1 ') preparing a matrix B comprising a hydrocarbon mixture (i) and butane; and then

[0095] 2') mixing from 64 to 95 wt% of said matrix B with from 5 to 36 wt% of ethanol; and preferably mixing from 70 to 85 wt% of said matrix B with from 15 to 30 wt% of ethanol.

[0096] The second embodiment described above and its preferred alternatives are preferred.

[0097] In this embodiment, the matrix B is advantageously obtained from vegetable raw materials. Thus, the matrix B is advantageously a matrix of biological origin.

[0098] As preferred matrices of biological origin, it is possible to use, among others, those produced from biomass, transformed into bio-hydrocarbons by known catalytic conversion processes.

[0099] Similarly, the ethanol is preferably bio-ethanol.

[0100] Thus, the composition according to the present application can be prepared entirely from vegetable source raw materials.

[0101] Use

[0102] Another object of the application is the use of the composition as described above to fuel a spark-ignition engine. The engine can be of direct injection type or of indirect injection type.

[0103] The fuel composition can advantageously be used to fuel both a traditional (so-called "general public" engine) automotive vehicle engine and a high-efficiency, high-power spark-ignition engine such as a racing engine. This can in particular be a naturally aspirated or turbocharged engine, or a hybrid engine, i.e. an internal combustion engine (internal combustion engine) coupled to an electric motor, used in a racing car (circuit or rally).

[0104] The following examples are merely intended to illustrate the application and should not be interpreted as limiting the scope thereof. Example

[0105] Example 1 :

[0106] This example was carried out using a bio-sourced hydrocarbon matrix B converted from bio-alcohols converted from biomass.

[0107] The matrix B had the following composition:

[0108] Table 1 - Matrix B

[0109]

[0110]

[0111] The fuel composition C according to the application has been prepared by mixing:

[0112] - 83.8% by weight of matrix B;

[0113] - 10.5% by weight of bioethanol;

[0114] - 3.8% by weight of butane;

[0115] - 1.9% by weight of bio-naphtha.

[0116] The bio-naphtha used had a density of 682.9 kg / m3at 15°C (according to standard NF EN ISO 12185) and a distillation curve (according to standard NF EN ISO 3405) of E70 = 28.1°C; E100 = 70.8°C and E150 = 99.5°C. 3

[0117] Engine tests have been carried out using, on the one hand, the fuel C according to the application, and on the other hand, a commercial fuel of SP95 E10 gasoline type (petroleum-sourced unleaded gasoline 95 containing 10% by volume of ethanol).​

[0118] During these tests, the fuel C according to the application, containing a very high proportion of matrix of biological origin, made it possible to obtain satisfactory performances in terms of engine power. In addition, a reduction of 53% in nitrogen oxide (NOx) emissions has been observed compared to the conventional SP95 E10 fuel.

[0119] Example 2 :

[0120] Two fuel compositions C1 and C2 have been prepared by mixing two hydrocarbon matrices with 32% by weight of bioethanol.

[0121] Composition C1 is according to the application and has been prepared using a hydrocarbon matrix in which C 5+ The amount of isoparaffins is 3.47 times (24.66:7.11) the amount of n-paraffins. 5+ The amount of isoparaffins is 3.47 times (24.66:7.11) the amount of n-paraffins.

[0122] The composition of which is detailed in the following table 2.

[0123] Table 2 - Composition C1

[0124]

[0125]

[0126] Composition C2 is a comparative composition which has been prepared using a hydrocarbon matrix in which C 5+ The amount of isoparaffins is 3.47 times (24.66:7.11) the amount of n-paraffins. 5+ The amount of isoparaffins is 3.47 times (24.66:7.11) the amount of n-paraffins.

[0127] The composition of which is detailed in the following table 3.

[0128] Table 3 - Composition C2

[0129] Compound Content (wt%) Olefin 0.96 C 6+ aromatic compounds 26.55 C 5+ n-alkanes 10.22 C 5+ isoparaffins 21.85 Naphthene 6.36 Butane 1.97 Bioethanol 32.0 Other (especially C3 paraffins) 0.09

[0130] The RON (Research Octane Number) of each of these compositions has been measured according to the method described in EN ISO 5164. The results obtained are detailed in the following table:

[0131] Table 4 - Results

[0132] Composition RON (EN ISO 5164) C1 - Invention 103 C2 - Comparison 100

[0133] Thus, the composition C1 according to the application has a measured RON very significantly higher than the comparative composition C2.

Claims

1. Fuel composition comprising: (i) from 60 to 94% by weight of a hydrocarbon mixture comprising: a) from 35 to 55% by weight of aromatic compounds; b) 30 to 50 weight percent of a mixture of n-paraffins and isoparaffins containing at least 5 carbon atoms, wherein the weight ratio of the amount of isoparaffins to the amount of n-paraffins is greater than or equal to 3; and c) from 5 to 15% by weight of naphthenes; (ii) from 5 to 36% by weight of ethanol; and (iii) from 1 to 10% by weight of butane.

2. The composition of claim 1, wherein, The hydrocarbon mixture (i) represents from 65 to 90% by weight relative to the total weight of the fuel composition.

3. The composition of claim 2, wherein, The hydrocarbon mixture (i) represents from 70 to 80% by weight relative to the total weight of the fuel composition.

4. The composition according to any one of claims 1 to 3, characterized in that, The aromatic compounds (i) a) are selected from alkylbenzenes comprising from 7 to 12 carbon atoms.

5. The composition according to any one of claims 1 to 3, characterized in that, The content of aromatic compounds (i) a) ranges from 40 to 53% by weight relative to the weight of the hydrocarbon mixture (i).

6. The composition according to any one of claims 1 to 3, characterized in that, The n-paraffins and iso-paraffins comprise from 5 to 12 carbon atoms.

7. The composition according to any one of claims 1 to 3, characterized in that, The hydrocarbon mixture (i) contains from 5 to 10% by weight of n-paraffins and from 20 to 45% by weight of iso-paraffins.

8. The composition according to any one of claims 1 to 3, characterized in that, The content of the mixture of n-paraffins and iso-paraffins (i) b) ranges from 32 to 45% by weight relative to the weight of the hydrocarbon mixture (i).

9. The composition according to any one of claims 1 to 3, characterized in that, The naphthenes (i) c) are selected from cyclic alkanes containing from 5 to 10 carbon atoms.

10. The composition according to any one of claims 1 to 3, characterized in that, The content of naphthenes (i) c) ranges from 7 to 13% by weight relative to the weight of the hydrocarbon mixture (i).

11. The composition according to any one of claims 1 to 3, characterized in that, The content of ethanol ranges from 10 to 30% by weight relative to the total weight of the fuel composition.

12. The composition according to any one of claims 1-3, wherein, The content of ethanol ranges from 20 to 25% by weight relative to the total weight of the fuel composition.

13. The composition according to any one of claims 1-3, wherein, The content of butane ranges from 1.5 to 8% by weight relative to the total weight of the fuel composition.

14. The composition according to any one of claims 1-3, wherein, It comprises at most 2.5% by weight of olefins.

15. The composition according to any one of claims 1-3, wherein, It comprises at most 1% by weight of olefins.

16. The composition according to any one of claims 1-3, wherein, The hydrocarbon mixture (i) is derived from plant raw materials.

17. Use of a composition as defined in any one of claims 1 to 16 for fueling a spark-ignition engine.

18. Use according to claim 17 for fueling a naturally aspirated or turbocharged spark-ignition engine or a hybrid engine.

19. Use according to claim 18 for fueling an engine used in a racing car.

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