vehicle

Abstract

Vehicle, preferably a work machine, in particular a wheel loader, with an internal combustion engine designed to be operated with a gaseous fuel, with a storage tank for storing the fuel, with an injector for supplying the fuel to the combustion chamber of the internal combustion engine, and with a line connecting the storage tank to the injector, wherein an outlet valve is provided which is located in the line or is in fluid communication with it, characterized in that a discharge device is connected downstream of the outlet valve which is designed to change at least one physical and / or at least one chemical property of the fuel, wherein the discharge device is designed to adjust the concentration of hydrogen in air below the explosive limit.

Description

[0001] The present invention relates to a vehicle, preferably a work machine, in particular a wheel loader, with an internal combustion engine designed to be operated with a gaseous fuel, with a storage tank for storing the fuel, with an injector for supplying the fuel to the combustion chamber of the internal combustion engine, and with a line connecting the storage tank to the injector, wherein an outlet valve is provided which is located in the line or is in fluid communication with it.

[0002] Such a vehicle is known from DE 10 2023 116 769 A1.

[0003] In combustion engines powered by gaseous fuel, such as hydrogen, the gaseous fuel is typically introduced into the combustion chambers via a common rail injection system. This injection system is preceded by a high-pressure accumulator, which is shared by the multiple injectors and supplies them with fuel. The operating pressure of the hydrogen in this high-pressure accumulator is, for example, approximately 15 bar.

[0004] To regulate the pressure at which the injectors are supplied with hydrogen, etc., an engine pressure regulator is provided, which is located in the fuel supply line from a tank to the aforementioned high-pressure accumulator. The pressure regulator can be integrated into either the engine assembly and / or the storage tank assembly.

[0005] Notwithstanding the fact that the combustion engine and fuel cell are operated with pressurized hydrogen, the storage tank can be designed as either a pressurized hydrogen tank or a liquid hydrogen tank. In the case of a liquid hydrogen tank, it is necessary to first convert the liquid hydrogen into the gas phase. This, apart from a number of other components in the supply line, generally requires the use of a pressure regulator before the hydrogen enters the engine, just as with a pressurized hydrogen tank. The solutions described below are applicable to both types of storage tank.

[0006] Situations may arise that require the fuel to be removed from the supply line, or part of it, or from the high-pressure accumulator itself, after the combustion engine has been switched off or before it has been restarted.

[0007] To achieve this goal, it is known to continue running the engine at idle for a certain period of time after receiving a shutdown command, in order to completely remove the fuel from this line or these parts of the line, or to a negligible level.

[0008] It is also known to discharge fuel via an exhaust valve to prevent unintended filling of the combustion chamber with fuel between engine shutdown and restart. Such unintended filling can occur because it cannot be guaranteed that the injectors remain completely sealed in the closed position throughout their entire service life, allowing fuel to enter the combustion chamber via a leakage current when the engine is switched off. It is known to discharge this fuel uncontrolled into the ambient atmosphere or into the vehicle's exhaust system.

[0009] The aforementioned uncontrolled release of fuel into the environment can lead to problematic situations, in particular to the ignition of the fuel-air mixture, which may then occur in the immediate vicinity of the vehicle. This can endanger people and also damage the vehicle.

[0010] The present invention is therefore based on the objective of avoiding such a dangerous situation or of further developing a vehicle of the aforementioned doctor in such a way that the risk of such a situation occurring is excluded by technical measures or the probability of occurrence is sufficiently reduced.

[0011] This problem is solved by a vehicle having the features of claim 1.

[0012] A discharge device is connected downstream of the outlet valve, which is designed to modify at least one physical and / or at least one chemical property of the fuel. The invention is thus based on the idea of ​​not simply releasing the fuel uncontrollably into the environment, but rather ensuring, via a discharge device, that problematic situations, such as the formation of an explosive mixture, are prevented or the probability of their occurrence is reduced.

[0013] The discharge device has the property of altering the fuel in at least one physical property, such as its density, its mixing ratio with another substance, etc., and / or in at least one chemical property. This also includes the possibility that the fuel undergoes a chemical reaction. For example, if the fuel is hydrogen, this could refer to its oxidation to water.

[0014] The present invention prevents the accumulation or formation of an ignitable or explosive fuel-air mixture in the immediate vicinity of the vehicle. Preferably, the discharge device is designed such that a fuel-air mixture is formed, but that it remains outside the explosive limits. This has the advantage that even in the presence of an ignition source, no explosion occurs.

[0015] For example, if it is a hydrogen-air mixture, the discharge device can be designed in such a way that the volume fraction of hydrogen in this mixture does not exceed the limit of 4 vol.%.

[0016] In one embodiment of the invention, it is provided that an engine pressure regulator is provided upstream of the injector, wherein the engine pressure regulator is designed to adjust the pressure at which the fuel is supplied to the injector, wherein it is preferably provided that a high-pressure accumulator is located between the engine pressure regulator and the injector.

[0017] The engine pressure regulator therefore has the task of setting a pressure level that is applied to the injectors and with which the hydrogen or other fuel is introduced into the combustion chamber when the injector is open.

[0018] An "injector" is any device used to supply fuel to the combustion chamber. This could be a simple valve, a nozzle, etc.

[0019] In a further embodiment of the invention, the motor pressure regulator is connected upstream of the exhaust valve.

[0020] The terms "upstream", "in front", "upstream" and "downstream", "downstream" and "upstream" used in this invention are to be understood in terms of the direction of fuel flow. Furthermore, it is pointed out that the terms "fuel" and "hydrogen" are to be understood interchangeably and encompass any fuel suitable for operating an internal combustion engine.

[0021] Furthermore, a shut-off valve may be provided upstream of the exhaust valve. To selectively drain the fuel, the shut-off valve is closed, so that the draining only affects the part of the piping system or line located between the shut-off valve and the injector.

[0022] The aforementioned shut-off valve can be located upstream of the engine pressure regulator. In this case, the fuel gas contained in the engine pressure regulator is also released. The shut-off valve can also be located downstream of the engine pressure regulator. In this case, the fuel gas contained in the engine pressure regulator is not released during the release process.

[0023] The dispensing device can be designed to atomize the fuel. "Atomizing" refers to the distribution or even application of the gaseous fuel. For example, active distribution could be achieved using a fan or other ventilator. This fan could, for instance, be the fan of the vehicle's cooling system.

[0024] The use of a cooling system fan requires that the engine or fan is still running when the fuel is drained.

[0025] Alternatively, a different fan can be used, such as an electric fan. This can also be used when the engine is off, for example, if there are starting problems or the ignition is switched off.

[0026] Other energy sources are also possible, such as a hydraulic storage unit or an emergency steering pump, etc.

[0027] A compressor, a blower, or another energy source can be connected upstream of the discharge device for active distribution.

[0028] However, the invention also covers the case where the dispensing device does not require such an energy source or does not have one. In this case, hydrogen is distributed into the environment within the dispensing device, resulting in a passive dispersal or distribution of the fuel, such as hydrogen.

[0029] In a further embodiment of the invention, a feed device may be provided that forms part of the discharge device or is connected upstream of the discharge device, wherein the feed device is configured to mix air with the fuel. In this case, therefore, not pure fuel is discharged into the environment, but an air-fuel mixture.

[0030] Preferably, in this case, the discharge device is a Venturi nozzle in which the fuel forms the main flow and the air is drawn in, for example, laterally or from the side. Thus, at the outlet of the discharge device, there is no longer pure fuel, but an air-fuel mixture. As described above, it is preferred if the discharge device or the Venturi nozzle is designed such that the lower explosive limit of 4 vol% hydrogen is not reached or exceeded.

[0031] The dispensing device may include means for burning the fuel, wherein the means are preferably configured as an ignition source designed to oxidize hydrogen or other fuel with oxygen. The ignition source is configured to ignite the flammable fuel-air mixture within a protected compartment of the dispensing device. A "protected compartment" is understood to be an area in which the explosion or combustion of the fuel can take place in a controlled manner without causing damage to parts of the vehicle or endangering persons in the vicinity of the vehicle.

[0032] The discharge device may also include a catalyst designed to enable and / or accelerate a chemical reaction of the fuel, preferably with oxygen or air. This chemical reaction can be carried out at ambient temperature or at an elevated temperature necessary for the chemical conversion. In the latter case, the discharge device may include a heating element to achieve the desired temperature.

[0033] It is conceivable that an acceleration device, in particular a Venturi nozzle, is arranged upstream of the catalyst, which is designed to increase the flow velocity of one or more reactants, e.g., via the catalyst and / or in a chamber. Preferably, the purpose of the Venturi nozzle is to accelerate the fuel, in particular hydrogen, so that upon entry into the chamber, the intake of air and sufficient mixing of air / hydrogen—in the case of hydrogen as fuel—to a hydrogen content of less than or equal to 4% by volume is ensured. This is, of course, also transferable to other fuels with appropriately adjusted volume fractions, since the invention is not limited to hydrogen, although hydrogen is a fuel preferred according to the invention.

[0034] As already stated above, the discharge device is designed to adjust the concentration of the dispensed fuel, in particular hydrogen, in air below the explosive limit.

[0035] According to the present invention, the fuel can be stored in the storage tank, for example, in liquid or gaseous form or in another form.

[0036] The fuel is preferably hydrogen.

[0037] It should be noted here that the terms "ein" and "eine" do not necessarily refer to exactly one of the elements, although this is a possible interpretation, but can also denote a plurality of elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely, the singular also includes several of the elements in question.

[0038] Furthermore, all features of the invention described herein can be combined with one another or claimed separately from one another as desired.

[0039] Further details and advantages of the invention will be explained in more detail with reference to an exemplary embodiment shown in the drawing.

[0040] They show: Fig. 1: A schematic view of the fuel supply system with discharge device according to the invention, Fig. 2: a schematic view of the discharge device with fan, Fig. 3: A schematic view of the discharge device without a fan, Fig. 4: a schematic view of the discharge device with compressor, Fig. 5: Schematic views of the discharge device as a Venturi nozzle, Fig. 6: a schematic view of the discharge device as a chamber with ignition source, Fig. 7: a schematic view of the discharge device with catalyst and Venturi nozzle and Fig. 8: A schematic view of the discharge device with motor pressure regulator, outlet valve and shut-off valve in a common housing.

[0041] In the figures, identical or functionally equivalent elements are marked with the same reference symbols.

[0042] Fig. Figure 1, with reference numeral 10, shows a tank containing hydrogen. The pressure in this tank 10 is, for example, 700 bar.

[0043] Downstream of tank 10 is a vehicle pressure regulator 20, which reduces the pressure to a value of, for example, 30 bar.

[0044] Downstream of this is the shut-off valve 30, by means of which the supply line Z, which connects the tank 10 to the engine M of the vehicle, can be shut off.

[0045] Downstream of the shut-off valve 30 is the motor pressure regulator 40, which reduces the pressure to a value, such as 13-15 bar, suitable for operating the motor M. Of course, it would also be possible to use only one pressure regulator.

[0046] Downstream of the engine pressure regulator 40, the outlet valve 50 is located in the supply line Z. In a first position, this connects the sections of the supply line Z located before and after the outlet valve 50, so that the gaseous fuel passes from the tank 10 to the engine M.

[0047] In a second position, the outlet valve 50 connects the section of the supply line Z located upstream of the outlet valve 50 to the line L, which leads to the discharge device 100. The discharge device 100 is thus in fluid contact with the line L on the inlet side and with the ambient atmosphere on the outlet side.

[0048] Reference numeral 60 designates the high-pressure accumulator, which is in fluid communication with a plurality of injectors, so that the fuel flows from the high-pressure accumulator 60 to the injectors. When these are open, the fuel enters the combustion chamber(s) B of the engine M.

[0049] In principle, the invention also covers the case where the outlet valve 50 and the discharge device 100 form a structural unit.

[0050] As this is shown Fig. As shown in Figure 2, the discharge device 100 can have a fan 110 or be in fluid communication with it, so that the fuel is actively conveyed to the discharge device 100. This fan can be a fan of the vehicle, i.e., a fan that otherwise serves another purpose, such as a fan of the vehicle's cooling system. Another energy source for conveying the fuel through the discharge device 100 is also conceivable and encompassed by the invention.

[0051] It is also conceivable that a fan specifically designed for the discharge device 100, such as an electric fan, is used.

[0052] The discharge device 100 according to Fig. 2 has the task of distributing the fuel so finely that its volume concentration in the ambient atmosphere is below the explosion limit.

[0053] Fig. Figure 3 shows an arrangement in which no active conveying medium is present for transporting the fuel through the discharge device 100; thus, a "passive" fine distribution of the fuel into the ambient air occurs. Particularly good distribution can be achieved, for example, by a watering can-like head, a baffle plate, etc.

[0054] According to Fig. 4. In the discharge device 100, the fuel gas is accelerated by a compressor 70. The acceleration in the outlet nozzle results in better dispersion / mixing with ambient air.

[0055] Fig. Figure 5a shows the design of the discharge device 100 as a Venturi nozzle. The fuel is designed to flow in a main stream, i.e., from left to right, through the discharge device 100. Air is drawn in through the inlet E. This air mixes inside the discharge device 100. The mixture is then discharged from the discharge device 100.

[0056] In the case of hydrogen according to Fig. 5b, this hydrogen, as 100% hydrogen a, enters the discharge device 100, where it is mixed with air b. The nozzle design, and thus the set air volume, is selected to achieve a hydrogen content of less than 4 vol%. In section c, the hydrogen and air are thoroughly mixed. The mixture d is then discharged.

[0057] Unlike previous application methods, this method involves dilution with air before application. The aim is for the exiting hydrogen-air mixture to contain only 4% hydrogen or less.

[0058] Dilution in a room followed by distribution is also conceivable. In this case, the dilution would not necessarily have to reach 4% by volume, because the subsequent distribution would result in further dilution.

[0059] Fig. Figure 6 shows an embodiment in which the discharge device 100 has a chamber 110 containing an ignition source 120. Fuel flows into chamber 110 through line L, and ambient air flows into chamber 110 through its inlet E. When the ignition source 120 is activated, the fuel is combusted in a controlled manner and the reaction product, in the case of hydrogen, water, is discharged.

[0060] In this example, undiluted hydrogen is burned in a "protected" space (protected meaning protection for a person in the immediate vicinity) – for example, in a pipe – using an ignition source. Oxygen is also supplied to achieve a mixture within the ignition limits, and "hot" steam is emitted at the end.

[0061] According to Fig. 7. It is provided that the fuel is converted using a catalyst 130. An ignition source is not provided in this case.

[0062] The catalyst 130 is preceded by chamber 110, which in turn is preceded by an accelerator 140. In this accelerator, the fuel is accelerated and then enters chamber 110. Air is supplied through its inlet E. A mixture of fuel and ambient air is produced in chamber 110, such as a hydrogen-air mixture with a hydrogen content of 4% by volume or less.

[0063] This mixture is then passed over catalyst 130. During this process, hydrogen is oxidized to water D, which is then released into the environment.

[0064] Preferably, dilution takes place during this process, provided this is necessary for oxidation in the catalyst. In addition to dilution, acceleration (Venturi nozzle) is carried out to ensure the reliable intake of ambient air for dilution of the hydrogen to a maximum of 4 vol%.

[0065] Following the nozzle 140, an oxidation catalyst 130 is connected, which burns the 4% H2 "cold" (flameless).

[0066] Fig. Figure 8 shows a design in which a line extends from the shut-off valve 30 to the motor pressure regulator 40 and a parallel line extends to the outlet valve 50.

[0067] In this embodiment, but also in principle, the motor pressure regulator 40, the outlet valve 50 and the shut-off valve 30 can be arranged in a common housing G.

[0068] By positioning the shut-off valve – viewed in the direction of flow – upstream of the engine's pressure regulator, the engine's pressure regulator is relieved of pressure when the residual hydrogen is released, because the shut-off is achieved by the shut-off valve. The shut-off valve could also be omitted, since the pressure regulator / vehicle configuration at the pressure regulator / engine results in a pressure of only about 30 bar, meaning that the shut-off could be accomplished using a suitable pressure regulating valve.

[0069] It would also be conceivable to arrange the outlet valve – in the direction of flow – in front of the pressure regulator / motor if one also wanted to drain the residual hydrogen located in the motor pressure regulator. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 116 769 A1

[0002]

Claims

[1] Vehicle, preferably a work machine, in particular a wheel loader, with an internal combustion engine designed to be operated with a gaseous fuel, with a storage tank for storing the fuel, with an injector for supplying the fuel to the combustion chamber of the internal combustion engine, and with a line connecting the storage tank to the injector, wherein an outlet valve is provided which is located in the line or is in fluid communication with it, characterized by that a discharge device is connected downstream of the exhaust valve, which is configured to change at least one physical and / or at least one chemical property of the fuel, wherein the discharge device is configured to adjust the concentration of hydrogen in air below the explosive limit. [2] Vehicle according to claim 1, characterized bythat an engine pressure regulator is present upstream of the injector, wherein the engine pressure regulator is designed to adjust the pressure at which the fuel is supplied to the injector, wherein it is preferably provided that a high-pressure accumulator is located between the engine pressure regulator and the injector. [3] Vehicle according to claim 2, characterized by that the engine pressure regulator is located upstream of the exhaust valve. [4] Vehicle according to any of the preceding claims, characterized by that a shut-off valve is present, which is located upstream of the outlet valve. [5] Vehicle according to one of claims 2 or 3, characterized by that a shut-off valve is present, located upstream or downstream of the engine pressure regulator. [6] Vehicle according to any of the preceding claims, characterized by that the discharge device is designed to atomize the fuel. [7] Vehicle according to claim 6, characterized bythat a compressor or a blower is connected upstream of the discharge device, or that the discharge device includes a compressor or a blower. [8] Vehicle according to any of the preceding claims, characterized by that a supply device is present which forms part of the discharge device or is located upstream of the discharge device, wherein the supply device is designed to mix air with the fuel. [9] Vehicle according to claim 8, characterized by that the discharge device and the feed device are designed as a Venturi nozzle. [10] Vehicle according to any one of the preceding claims, characterized by that the discharge device has means for burning the fuel, wherein the means are preferably designed as an ignition source that oxidizes hydrogen with oxygen. [11] Vehicle according to any of the preceding claims, characterized bythat the discharge device has a catalyst designed to enable a chemical reaction of the fuel, preferably with oxygen. [12] Vehicle according to claim 11, characterized by that an acceleration device, in particular a Venturi nozzle, is connected upstream of the catalyst, which is designed to increase the flow rate, preferably of the hydrogen. [13] Vehicle according to any one of the preceding claims, characterized by that the fuel in the storage tank is in a gaseous or liquid state. [14] Vehicle according to any of the preceding claims, characterized by that the fuel is hydrogen or that the fuel contains hydrogen.

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