Method for determining the quality of a fuel
Patent Information
- Application Number
- PCT/EP2026/055726
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-12
- Filing Date
- 2026-03-03
- Publication Date
- 2026-09-17
Smart Images
Figure EP2026055726_17092026_PF_FP_ABST
Abstract
Description
[0001] Mercedes-Benz Group AG
[0002] Method for determining the quality of a fuel
[0003] The invention relates to a method for determining the quality of a fuel.
[0004] DE 102019124673 A1 is a method for determining different properties of paraffinic liquids, in particular cold properties of liquid fuels in a fuel supply system, which is known in that an outside temperature near the fuel supply system is determined by an outside temperature sensor both outside and inside an operation of the fuel supply system.
[0005] The object of the present invention is to provide a method by which the quality of a fuel can be determined particularly advantageously.
[0006] This problem is solved by a method with the features of claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.
[0007] The invention relates to a method for determining the quality of a fuel, particularly a liquid fuel, stored in the fuel tank of a motor vehicle, which is designed to power the vehicle's internal combustion engine. This means that the motor vehicle has an internal combustion engine and can be driven by it, with the engine being capable of operating under fire using the fuel. Preferably, the internal combustion engine is a diesel engine, so the fuel stored in the fuel tank is preferably diesel fuel. "Operating under fire" means that combustion processes take place within the engine during this operation.During each combustion process, a specific mixture is burned, resulting in exhaust gas from the internal combustion engine. This mixture consists of fuel and air.
[0008] For example, the procedure is carried out using an electronic computing device, in particular a motor vehicle.
[0009] In this process, a predetermined or specified initial quantity of water is introduced from a water tank, particularly one provided in addition to the fuel tank, into the fuel tank and thus into the fuel contained within it. This creates a mixture of the fuel and the water introduced into the fuel tank. Thus, in this process, the water is absorbed into the water tank. For example, a pump, particularly an electric one, is used in the vehicle to draw the initial quantity of water from the water tank and pump it into the fuel tank, thereby introducing it into the fuel contained within.When the mixture is mentioned below, unless otherwise stated, it refers to the mixture of the fuel taken into the fuel tank and the water introduced into the fuel tank.
[0010] In this process, a predetermined or specified third quantity of the mixture is fed from the fuel tank to a separator in the vehicle. For this purpose, the third quantity of the mixture is, for example, extracted from the tank by means of the aforementioned pump and / or by means of at least one second pump, particularly an electric pump, and conveyed to the separator. The third quantity of the mixture then flows through the separator. Water is separated from the mixture supplied to the separator by means of the separator.This means that the separator separates the water and fuel contained in the mixture supplied to the separator, thus separating them from each other. The separator removes the water from the mixture supplied to the separator. In this process, a third quantity of the water separated from the mixture by the separator is determined, particularly using the electronic computing device.
[0011] For example, the third quantity of water separated from the mixture by the separation device is measured by means of a sensor. The sensor provides, for example, a signal, in particular an electrical signal, characterizing the measured third quantity, wherein, for example, the electronic computing device receives the signal, thereby determining the third quantity, or the electronic computing device determines the third quantity depending on the received signal.
[0012] In this process, the quality is determined as a function of the third quantity, in particular by means of an electronic computing device. Determining the quality means that, in particular by means of an electronic computing device, at least one quality value characterizing the quality of the fuel incorporated into the fuel is determined, in particular calculated, as a function of the third quantity.
[0013] It is evident that the invention utilizes the ability or capacity of the fuel stored in the fuel tank to dissolve or absorb water in order to advantageously determine its quality or quality value. The fuel's capacity to dissolve or absorb water is also referred to as its solubility, and this solubility is used by the inventive method to determine the quality. In other words, the invention utilizes the solubility of water in the fuel stored in the fuel tank to determine its quality.
[0014] For example, the method provides that the motor vehicle, in particular the internal combustion engine, is operated depending on the determined quality, especially depending on the determined quality value. In particular, it is conceivable that the operation of the internal combustion engine is carried out, and in particular varied, depending on the determined quality, especially depending on the determined quality value. The invention is based in particular on the following findings and considerations: The supply of paraffinic fuels, in particular paraffinic diesel fuels, for example according to standard EN 15940 (for example HVO), is steadily increasing. These fuels promise a CO2 reduction potential of up to 95% compared to conventional fossil fuels.Furthermore, these paraffinic fuels are characterized by significantly advantageous physicochemical fuel properties. For example, paraffinic diesel fuels have a considerably higher cetane number compared to fossil-based diesel fuels, resulting in shorter ignition delays and higher combustion efficiency. Compared to fossil-based diesel fuels, paraffinic diesel fuels have a lower boiling point, resulting in a reduced risk of oil dilution. The aromatic content of paraffinic diesel fuels is lower compared to fossil-based diesel fuels, resulting in lower particulate emissions and extended regeneration intervals for diesel particulate filters.Compared to conventional fossil diesel fuels, paraffinic diesel fuels have a significantly lower sulfur content, thus preventing sulfur poisoning of exhaust aftertreatment systems. The hydrogen-to-carbon ratio in paraffinic diesel fuels is more than 10% higher than in conventional fossil diesel fuels, which reduces CO2 emissions. Paraffinic diesel fuels also exhibit higher oxidation stability compared to conventional fossil diesel fuels, resulting in better storage stability.Another difference between conventional fossil fuels, in particular conventional fossil diesel fuels, and paraffinic fuels, in particular paraffinic diesel fuels, is – and this difference is utilized by the invention – water solubility, in that paraffinic fuels, in particular paraffinic diesel fuels, have a significantly lower water solubility compared to conventional fossil diesel fuels, resulting in a higher water separation rate.
[0015] Since both fuel variants, i.e., both paraffinic fuels and conventional fossil fuels, are available at gas stations and can therefore be used, and since conventional system applications for motor vehicles with internal combustion engines are primarily based on fossil fuels, it would be highly desirable and advantageous to detect refueling with paraffinic fuel in order to then, for example, adapt the system parameters to this fuel. The invention thus makes it possible, for example, to operate the motor vehicle, in particular the internal combustion engine, according to the determined quality, specifically the determined quality value, either according to a first operating strategy or according to a second operating strategy that differs from the first.According to the first operating strategy, the motor vehicle, and in particular the internal combustion engine, is operated, for example, when the determined quality indicates that the fuel in the fuel tank is a conventional fossil-based fuel. According to the second operating strategy, the motor vehicle, and in particular the internal combustion engine, is operated, for example, when the determined quality, and in particular the determined quality value, indicates that the fuel in the fuel tank is a paraffinic fuel. This allows the internal combustion engine and its associated drive system to be optimized for specific fuel parameters with regard to fuel consumption, performance, and emissions, thus enabling fuel-efficient and low-emission operation with high vehicle performance.In particular, the invention makes it possible to precisely and reliably identify, and thus determine, whether the fuel in the fuel tank is a conventional fossil-based fuel or a paraffinic fuel, depending on the determined quality, especially depending on the determined quality value. The invention thereby utilizes the significantly reduced water solubility of paraffinic fuels compared to conventional fossil-based fuels, so that, for example, it can be determined, depending on the determined quality, whether the fuel in the fuel tank is a paraffinic fuel or a conventional fossil-based fuel.
[0016] In order to determine the quality of the fuel currently in the fuel tank particularly advantageously, one embodiment of the invention provides that a temperature in the vehicle's environment, also referred to as ambient temperature, and / or a temperature of the water in the water tank, also referred to as water temperature, and / or a temperature of the fuel in the fuel tank, also referred to as fuel temperature, is determined. For example, the respective temperature is measured and thus recorded by means of a temperature sensor.
[0017] It has proven particularly advantageous to adjust, i.e., vary, the first quantity and / or the second quantity depending on the determined ambient temperature and / or the determined water temperature and / or the determined fuel temperature. Thus, if the temperature has a first temperature value, a first quantity value for the first quantity and / or the second quantity is set. If, for example, the temperature has a second temperature value that differs from the first, a second quantity value for the first quantity and / or the second quantity that differs from the first is set. This allows the first or second quantity to be adapted particularly effectively to the temperature, enabling a particularly reliable and precise determination of the fuel quality based on the solubility of the fuel absorbed by the fuel.
[0018] In order to determine the quality of the fuel taken up in the fuel tank particularly advantageously, a further embodiment of the invention provides that a fourth quantity of the fuel taken up in the fuel tank is determined.
[0019] For example, the fourth quantity is measured by means of a sensor device, that is, detected and thereby determined. Furthermore, it is conceivable that the fourth quantity is calculated and thereby determined by means of the electronic computing device. The fourth quantity is a quantity of fuel taken into the fuel tank, such that the fourth quantity is taken into the fuel tank.
[0020] To determine the quality with particular precision and reliability, a further embodiment of the invention provides that the first quantity is adjusted, i.e., varied, depending on the determined fourth quantity of fuel taken up in the fuel tank. This allows the first quantity to be particularly advantageously adapted to the fourth quantity, so that the quality can be determined advantageously, precisely, and reliably based on the solubility of the fuel taken up in the fuel tank.
[0021] In order to determine the quality in a particularly advantageous way, it is provided in a further embodiment of the invention that, in particular by means of the electronic computing device, at least one value characterizing at least the third quantity is determined, in particular calculated.
[0022] It has proven particularly advantageous if the value characterizes the third quantity relative to the second quantity, or if the value characterizes the third quantity relative to a fifth quantity, where the fifth quantity is a quantity of fuel separated from the mixture by the separator. In other words, since water is separated from the mixture by the separator and thus separated from the fuel contained in the mixture, conversely, the fuel contained in the mixture supplied to the separator is separated from the mixture, and thus separated from the water contained in the mixture supplied to the separator.The fifth quantity is a quantity of fuel that is separated from the mixture supplied to the separator by means of the separator device, such that water is separated from the mixture supplied to the separator device. The fifth quantity can be determined, for example, by subtracting the third quantity from the second quantity. Therefore, it is preferably provided that the fifth quantity is determined in the process, particularly by means of an electronic computing device. For example, the fifth quantity is measured and determined by means of a sensor. Furthermore, it is conceivable that the fifth quantity is calculated and determined, particularly by subtracting the third quantity from the second quantity.
[0023] To determine the fuel quality particularly advantageously, a further embodiment of the invention provides that a comparison is carried out, in particular by means of the electronic computing device. In this comparison, the value is compared with data that characterize at least one graph, in particular at least one curve, wherein the graph describes the solubility of water in a given reference fuel as a function of a temperature of the reference fuel. Thus, the graph is, for example, a solubility graph, in particular a solubility curve, of the reference fuel.The feature that the graph, and thus the data, describe the solubility of water in the specified reference fuel as a function of the reference fuel's temperature means that the data assign a specific solubility value to each temperature value of the reference fuel, also referred to as the reference fuel temperature. This solubility value characterizes, that is, indicates, describes, or defines, the solubility of water in the reference fuel, specifically the solubility of a mass of water in a mass of the reference fuel. The quality is determined based on this comparison. To enable a more precise determination of the quality, a further embodiment of the invention provides for comparisons to be performed based on the determined temperature, particularly the determined fuel temperature.For example, when determining the temperature, at least one temperature-characterizing value is determined. For example, depending on the determined temperature, and in particular depending on the determined temperature value, a first solubility value is determined from the data, specifically precisely, for example, such that the data assign the first solubility value to the determined temperature value, or vice versa. In other words, for example, the solubility value used as the first solubility value is the one to which the data assigns the temperature value that corresponds to or is closest to the determined temperature value.If the determined value corresponds to the first solubility value, or if the deviation of the value from the first solubility value is less than or equal to a predefined or predetermined threshold, it can be concluded that the fuel currently in the fuel tank corresponds to, or at least closely resembles, the reference fuel. If the reference fuel is, for example, a paraffinic fuel, in particular a paraffinic diesel fuel, then it can be concluded that the fuel currently in the fuel tank is a paraffinic fuel, in particular a paraffinic diesel fuel.However, if, for example, the deviation of the value from the first solubility value is greater than the threshold value, it can be concluded that the fuel currently being taken into the fuel tank is a different fuel from the reference fuel, so that, for example, it can be concluded that the fuel currently being taken into the fuel tank is not a paraffinic fuel, but a conventional fossil fuel, in particular conventional fossil diesel fuel.
[0024] Finally, it has proven particularly advantageous if the water separated from the mixture by the separator is fed directly into the water tank. This ensures particularly efficient operation of the motor vehicle.
[0025] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.
[0026] The drawing shows in:
[0027] Fig. 1 shows a schematic representation of a fuel tank and a water tank of a motor vehicle;
[0028] Fig. 2 shows a schematic and cutaway side view of a motor vehicle separation device; and
[0029] Fig. 3 is a diagram illustrating a method for determining the quality of fuel taken up in the fuel tank.
[0030] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.
[0031] The following describes a method for determining the quality of fuel stored in the fuel tank of a motor vehicle and intended for operating the vehicle's internal combustion engine, with reference to Figures 1 to 3. The fuel tank in question is shown schematically in Figure 1 and is designated 10. In this method, the fuel, preferably liquid, is contained in the fuel tank 10, so that the fuel is currently contained within the fuel tank 10. In this method, a predetermined or specified initial quantity of water is introduced from a water tank 12 of the motor vehicle (also shown very schematically in Figure 1) into the fuel tank 10 and thus into the fuel contained therein. This creates a mixture in the fuel tank 10 of the fuel contained therein and the water introduced into the fuel tank 10 from the water tank 12.In this method, a predetermined or specified second quantity of the mixture from the fuel tank 10 is fed to a separator 14 of the motor vehicle, which is shown schematically in Fig. 2. The mixture fed to the separator 14 flows, for example, through at least a portion of the separator 14. The method is carried out, for example, by means of an electronic computer in the motor vehicle. The water tank 12 is, for example, equipped with a heater, particularly an electric one, by means of which the water tank 12, and thus the water contained in the water tank 12, can be heated. This prevents the water in the water tank 12 from freezing. For example, the first quantity of water is pumped from the water tank 12 to and into the fuel tank 10 by a pump (not shown).The mixture is conveyed from the fuel tank 10 to the separator 14 by means of the pump and / or a second pump. A filter (not shown in Fig. 1) is provided, for example, to filter the water flowing from the water tank 12 to the fuel tank 10. A sensor is also provided, for example, to measure the initial quantity. Thus, the water is conveyed from the water tank 12 to the fuel tank 10 by the pump until the initial quantity is measured by the sensor. A metering device may also be provided, in particular, to introduce, or meter, the initial quantity into the fuel tank 10 and thus into the fuel contained therein.
[0032] For example, a refueling process is detected, particularly by means of a vehicle detection device, whereby the fuel tank 10 is at least partially filled with fuel. Specifically, depending on the detection of the refueling process, water from the water tank 12 is introduced into the fuel tank 10 and thus into the fuel contained in the fuel tank 10.
[0033] For example, the temperature of the fuel held in fuel tank 10, also referred to as the fuel temperature, is determined, in particular by recording and thereby ascertaining it. It is preferably provided that the initial quantity of water is adjusted, i.e., varied, depending on the determined fuel temperature. Thus, the initial quantity, also referred to as the quantity of hot water, is temperature-dependent, and therefore dependent on the fuel temperature. Specifically, the initial quantity of water is introduced into fuel tank 10 to saturate the fuel held there. By introducing the water from water tank 12 into fuel tank 10, the water introduced into fuel tank 10 can dissolve, at least to a certain extent, in the fuel held there.
[0034] In Fig. 2, arrow 16 illustrates the mixture comprising water and fuel, originating from the fuel tank 10, which is fed to the separator 14. Water is separated from the mixture by means of the separator 14. This means that the water contained in the mixture fed to the separator 14 and the fuel, preferably liquid, contained in the mixture fed to the separator 14 are separated from each other. In other words, the separator 14 separates the water contained in the mixture fed to the separator 14 from the fuel contained in the mixture fed to the separator 14, and vice versa.The water separated by the separator 14 is illustrated by arrow 18 and is also referred to as separated water, and the fuel separated by the separator 14, in particular diesel fuel, is illustrated by arrow 20 and is also referred to as separated fuel. The separator 14, for example, performs water droplet separation supported by a filter material 22 of the separator 14, by means of which the water is separated from the mixture supplied to the separator 14 and thus separated, thereby separating the fuel contained in the mixture from the mixture supplied to the separator 14. In the process, a third quantity of the water separated from the mixture by the separator 14 and illustrated by arrow 18 is determined, in particular by means of the electronic computing device.For example, the separator 14 has a water outlet 24 with a detection device by means of which the third quantity is measured and thus recorded and determined as the separated water flows through the water outlet 24 to discharge the water separated by the separator 14 from the separator 14 and, for example, in particular directly into the water tank 12. Using the aforementioned sensor, the second quantity, or rather an actual value of the second quantity, is measured and thus determined as the water flows from the water tank 12 to and into the fuel tank 10. The electronic control unit specifies, for example, a target value for the second quantity, whereby the water from the water tank 12 is introduced into the fuel tank 10 until the measured actual value corresponds to the target value.For example, additional sensors are provided to measure and determine the temperature of the fuel held in fuel tank 10, also known as fuel temperature. The first quantity of fuel is adjusted based on this measured fuel temperature. Furthermore, it is conceivable that the second quantity is adjusted based on the measured fuel temperature.
[0035] Alternatively or additionally, a fourth quantity of the fuel taken up in fuel tank 10, particularly as a result of the refueling process, is measured and determined using further sensors. The first quantity is then adjusted, i.e., varied, depending on the fourth quantity.
[0036] The electronic computing device determines, for example, a value that characterizes the third quantity relative to the second quantity, or the value characterizes the third quantity relative to a fifth quantity of the fuel separated from the mixture by the separator 14, as illustrated by arrow 20. The fifth quantity can be measured and determined, for example, by means of a sensor. Furthermore, it is conceivable to subtract the third quantity from the second quantity and thus calculate and determine the fifth quantity.
[0037] Fig. 3 shows a diagram 26, on whose abscissa 28 a temperature is plotted, increasing from left to right relative to the plane of Fig. 3. The diagram 26 has an ordinate 30, on which a quantity of dissolved or, in particular, maximally soluble water, also referred to as solubility or solution quantity, is plotted, increasing from bottom to top relative to the plane of Fig. 3, i.e., increasing. Three graphs 32a-c are plotted in the diagram 26. Graph 32a illustrates the solubility of water in a given first reference fuel, which in this case is a methyl ester-based biodiesel fuel (FAME), as a function of the temperature plotted on the abscissa 28.Graph 32b illustrates the solubility of water in a given second reference fuel, which is, for example, a conventional fuel, especially diesel fuel, as a function of the temperature plotted on abscissa 28.
[0038] Accordingly, graph 32c illustrates the solubility of water in a given third reference fuel, which is, for example, a paraffinic diesel fuel different from the first and second fuels, as a function of the temperature plotted on abscissa 28. In particular, the second reference fuel is a different fuel from the first and third reference fuels, especially diesel fuel. The temperature plotted on abscissa 28 is thus the respective temperature of each reference fuel. For example, data characterizing diagram 26, and thus graphs 32a-c and therefore the solubility of water in the reference fuels, can be stored in a data storage device, particularly an electrical or electronic one, of the electronic computing unit.Using the electronic computing device, a comparison is performed, for example, in which the aforementioned value is compared with the data, and the quality is determined based on this comparison. For the respective reference fuel, a solubility value is determined, for example, depending on the determined fuel temperature. This value characterizes, that is, specifies, defines, or describes the solubility of water in the respective reference fuel at the determined ambient temperature. The aforementioned value is then compared with the solubility values. If the value corresponds to one of the determined solubility values, it is concluded that the fuel currently in fuel tank 10 corresponds to the reference fuel for which the solubility value determined corresponds to the value determined for the third quantity.If, for example, the determined value characterizing the third quantity does not correspond to any of the determined solubility values, then the solubility value from which the determined value characterizing the third quantity deviates least, relative to all determined solubility values, is determined. Consequently, it is concluded, for example, that the fuel currently in fuel tank 10 corresponds to or is similar to the reference fuel for which the solubility value determined was the one from which the determined value characterizing the third quantity deviates least. Thus, it can be determined whether the fuel currently in fuel tank 10 is one of the reference fuels or a different, paraffinic, or conventional fossil fuel.
[0039] With regard to Fig. 3, it should be noted that on the ordinate 30 the amount of water dissolved or, in particular, the maximum soluble amount of water in the respective reference fuel, and thus the solubility of water in the respective reference fuel, is plotted logarithmically.
[0040] In the embodiment shown in Fig. 3, the first reference fuel (Graph 32a) is a methyl ester-based biodiesel fuel (FAME), the second reference fuel is a diesel fuel, in particular a fossil diesel fuel (Graph 32b), especially according to standard EN 590, and the third reference fuel (Graph 32c) is, for example, a purely paraffinic diesel fuel such as HVO according to standard EN 15940. It can be seen that the conventional diesel fuel (Graph 32b) can dissolve, in particular, at most twice the amount of water as the purely paraffinic diesel fuel (Graph 32c). Furthermore, the methyl ester-based biodiesel fuel (FAME) (Graph 32a), due to its polarity, can dissolve an amount of water that is more than one hundred times greater than the amount of water that can be dissolved, in particular at most, in the other reference fuels. Commercially available diesel fuels of B7 quality (up to 7 vol.Fuels containing -% FAME exhibit significantly higher water solubility compared to HVO fuels. These properties are used in the process to determine fuel quality.
[0041] Introducing water from water tank 12 into the fuel, especially diesel fuel, stored in fuel tank 10 also has advantages in the case of combustion of the fuel, particularly in the case of diesel combustion:
[0042] Reduced NOx emissions: Water lowers the combustion temperature, leading to a reduction in nitrogen oxide (NOx) emissions.
[0043] Improved combustion: The water content can improve combustion by promoting fuel atomization and enabling more complete combustion through better vaporization and mixture formation. Cooling: Water has a cooling effect that can help lower the temperature in the combustion chamber and thus reduce the thermal stress on engine components.
[0044] Soot reduction: Improved combustion can also reduce soot formation.
[0045] For example, if the refueling process detects that more than 20% of the fuel tank 10's volume, preferably more than 50%, has been filled with fuel, the first quantity from the water tank 12 is added to the fuel tank 10. Furthermore, the fourth quantity of fuel already in the fuel tank 10 is then determined, in particular by means of a level sensor in the fuel tank 10. Thus, the level sensor is, for example, part of the aforementioned additional sensor system. The first quantity of water is then added to the determined fourth quantity, in particular according to graph 32a, which is, for example, a water saturation curve of the first reference fuel.For example, if the fourth quantity is 20 kg (converted from a fuel volume using an average fuel density), then, assuming a temperature of 20°C, 160 mg will be added; thus, the first quantity will then be 160 mg. Using the separator 14, which is installed as standard equipment and is specifically designed as a water separator, free, i.e., undissolved, water is separated from the mixture supplied to the separator 14, and the third quantity is determined. The third quantity extracted from the separator 14 can be returned directly to the water tank 12, thus advantageously enabling long refill intervals and ensuring easy maintenance.
[0046] The third quantity of water separated by the separation device 14 is determined, for example, by means of a calibrated sensor, which may include an optical sensor and / or an ultrasonic sensor and / or a capacitive sensor. The second quantity is, for example, in a range from 100 ml to 5 L inclusive, and in particular in a range from 1 L to 2 L inclusive. After the predefined or predetermined second quantity has been treated by the separation device 14 to separate the third quantity of water, the third quantity is determined and, for example, temperature-corrected, correlated in the electronic computing device with the graphs 32a-c, which are, for example, designed as saturation curves.
[0047] For example, a case distinction is made. If the third quantity falls below a certain threshold, where the third quantity can be zero or greater than zero, it is concluded, for example, that the fuel taken in by fuel tank 10 is a saturated diesel fuel with 7% FAME by volume. If the third quantity is a typical quantity for paraffinic diesel fuels according to diagram 26 or the data characterizing diagram 26, then the fuel taken in by fuel tank 10 is determined to be, in particular, pure paraffinic diesel fuel. If, for example, the determined third quantity does not allow for a clear evaluation or determination of the quality, a plausibility check is performed.During plausibility checks, for example, a predetermined or specified quantity of water is again introduced from water tank 12 into fuel tank 10, and the resulting mixture is treated by means of the separator 14. Alternatively or additionally, it is conceivable that an optical sensor detects any turbidity of the fuel mixture resulting from the introduction of water from water tank 12 into fuel tank 10, particularly in comparison to the fuel in tank 10 before the introduction of water, especially through relatively high light absorption.The detected turbidity due to light absorption or light scattering, especially at interfaces between the two liquid phases fuel and water, indicates that the solubility limit has been exceeded by the first dosed amount, thereby confirming the case distinction or initiating a new measurement.
[0048] As another option, a small volume of fuel can be tested in a separate chamber during refueling using the described method. Ideally, this chamber fills up during the refueling process itself. The known quantity of fuel in this chamber can then be mixed with a significantly smaller quantity of water to perform the fuel quality differentiation described above. This small volume is then used as the previously mentioned fuel tank 10.
[0049] The process offers at least the following advantages: Through clear and rapid identification of the paraffinic fuel used, combustion and exhaust aftertreatment systems can be advantageously adapted to the fuel.
[0050] Efficiency-optimized combustion control by utilizing high cetane numbers and reducing mechanical overload due to critical pressure gradients in the combustion chamber. Combustion chamber pressure measurement can provide additional support in this regard.
[0051] Adaptation of combustion processes to the reduced energy content; extension of the DPF generation interval (fuel consumption advantage and reduced exhaust aftertreatment system aging)
[0052] By applying an equalization of PM / PN emissions during operation with paraffinic fuels, there is the potential for a significant reduction in raw NOx emissions (NOx / PM target conflict).
[0053] Extended sulfur regeneration interval (fuel consumption benefit and reduced exhaust aftertreatment system aging)
[0054] Benefits of operating with CO2-neutral fuel. Reference list
[0055] 10 Fuel tank
[0056] 12 Water tank separator 16 Arrow
[0057] 18 Arrow
[0058] 20 Arrow
[0059] 22 filter material
[0060] 24 Water outlet
[0061] 26 Diagram
[0062] 28 Abscissa
[0063] 30 ordinates
[0064] 32a-c Graph
Claims
Mercedes-Benz Group AG Patent claims 1. Method for determining the quality of a fuel received in a fuel tank (10) of a motor vehicle and designed to operate an internal combustion engine of the motor vehicle, wherein: - a predetermined or specified first quantity of water from a water tank (12) of the motor vehicle is introduced into the fuel tank (10) and thereby into the fuel received in the fuel tank (10), forming a mixture in the fuel tank (10) of the fuel received in the fuel tank (10) and the water introduced into the fuel tank (10); - a predetermined or specified second quantity of the mixture from the fuel tank (10) is supplied to a separator device (14) of the motor vehicle; - water is separated from the mixture by means of the separator (14); - a third quantity of the water separated from the mixture by means of the separating device (14) is determined; and - the quality is determined depending on the third quantity.
2. Method according to claim 1, characterized by the fact that a temperature in the environment of the motor vehicle and / or a temperature of the water taken up in the water tank (12) and / or a temperature of the fuel taken up in the fuel tank (10) is determined.
3. Method according to claim 2, characterized in that the first quantity and / or the second quantity is adjusted depending on the determined temperature in the environment of the motor vehicle and / or depending on the determined temperature of the water taken up in the water tank (12) and / or depending on the determined temperature of the fuel taken up in the fuel tank (10).
4. Method according to any one of the preceding claims, characterized by the fact that a fourth quantity of the fuel taken up in the fuel tank (10) is determined.
5. Method according to claim 4, characterized by the fact that the first quantity is adjusted depending on the determined fourth quantity of fuel taken up in the fuel tank (10).
6. Method according to any one of the preceding claims, characterized by the fact that at least one value characterizing at least the third set is determined.
7. The method of claim 6 with reference to claim 4 or 5, characterized in that The value characterizes the third quantity relative to the second quantity or relative to a fifth quantity of the fuel separated from the mixture by means of the separating device.
8. Method according to claim 6 or 7, characterized by the fact that A comparison is carried out in which the value is compared with data that characterize at least one graph describing the solubility of water in a given reference fuel as a function of the temperature of the reference fuel, with the quality being determined as a function of the comparison.
9. A method according to claim 8 by reference to claim 6 to claim 2 or 3, or according to claim 8 by reference to claims 6 and 4 to claim 2 or 3, or according to claim 8 by reference to claims 6, 5 and 4 to claim 2 or 3, or according to claim 8 by reference to claims 7, 6 and 4 to claim 2 or 3, or according to claim 8 by reference to claims 7, 6, 5 and 4 to claim 2 or 3, characterized by the fact that The comparison is carried out depending on the measured temperature.
10. Method according to any one of the preceding claims, characterized by the fact that the water separated from the mixture by means of the separator (14) is introduced into the water tank (12).