FUEL SYSTEM FOR A PRESSURE TANK AND FOR A GAS-POWERED VEHICLE

Description

[0001] The invention relates to a fuel system for installation in a hydrogen-powered vehicle and designed for one or more hydrogen pressure tanks, operating at a high pressure level of at least 200 bar. The fuel system comprises a connection for an inlet line, a connection for an outlet line, and a pressure reducer. The pressure reducer is designed to reduce the pressure of the hydrogen from the high pressure level in the pressure tank to a medium pressure level between 3 bar and 30 bar.

[0002] Hydrogen-powered vehicles, for example, are powered by a gas engine or a fuel cell with an electric motor. To ensure sufficient fuel storage, the hydrogen is stored in the tank under high pressure. Typical pressures for such pressure tanks are over 200 bar, often 350 bar or 700 bar, and sometimes even up to 875 bar. Since the gas engine or fuel cell operates at a lower inlet pressure, the pressure must be reliably regulated from a high-pressure level to a low-pressure level.

[0003] Fuel systems for hydrogen pressure tanks and for installation in hydrogen-powered vehicles are known in the prior art. These are described, for example, in DE 102019200459 A1, WO 2020 / 079329 A1, FR 2 985 783 A1, and DE 102017214184 A1. A pressure reducer reduces the pressure level from the tank pressure to the required lower pressure level for a fuel cell. A control device and a pressure sensor on the pressure tank can be used to determine the fill level and communicate with a filling station if necessary. In addition, the fuel system features shut-off valves and pipes connected via appropriate screw connections. If several pressure tanks are connected in parallel, additional distribution points for the various tank lines are required. All of these components and connection points must be tested and inspected after installation.This causes considerable effort and carries risks in terms of incorrect installation and resulting leaks.

[0004] The object of the invention is to further develop and improve a fuel system for a hydrogen-powered vehicle so that it can be operated reliably and safely and can be assembled quickly and without errors.

[0005] The object is achieved by a fuel system according to claim 1. Further advantageous features are mentioned in the dependent claims.

[0006] According to the invention, the fuel system according to claim 1 is characterized in that it comprises at least the following internal components: a pressure reducer, a gas filter, a shut-off valve, a vent valve, an overpressure safety valve and a pressure sensor, wherein the pressure reducer is designed as a two-stage pressure reducer such that in the first stage it reduces the pressure from the pressure tank to an intermediate level between 40 and 80 bar and in the second stage it further reduces the pressure to the medium pressure level, and wherein the internal components and gas lines which connect these internal components to one another are arranged in an integral and self-supporting structural unit.

[0007] The medium pressure level is particularly preferred between 10 and 25 bar. A two-stage pressure reducer allows for more precise pressure adjustment.

[0008] To make the fuel system more reliable and safer in operation, it includes other components in addition to the pressure reducer. A vent valve, through which the system can be flushed, for example, after maintenance work. A gas filter, which retains small impurities from the pressure tanks and thus ensures the high-purity hydrogen required to extend the service life of a fuel cell. A shut-off valve, with which the fuel system can be isolated from the fuel cell or the gas engine. An overpressure safety valve, which protects the fuel system against excessive pressure and is preferably located downstream of the pressure reducer in the flow direction. A pressure sensor for measuring the state of the hydrogen gas. From these measured values ​​– if necessary in conjunction with measured values ​​from sensors on the pressure tank – the amount of hydrogen present in the pressure tank can be determined more reliably and precisely.This is important information for calculating the range of a vehicle and for refueling.

[0009] In addition, all internal components, as well as the corresponding gas lines that connect the internal components, are arranged in an integral and self-supporting unit. This offers the advantage that the fuel system according to the invention can be pre-assembled as a single module, independent of the vehicle and independent of the pressure tank. This pre-assembled fuel system can then be tested in advance and approved for safety and quality. This means that the fuel system can be offered for the first time as a self-contained module. Installation in the vehicle is less complex because only a few connections need to be connected and all internal components and connections have already been tested for function and leaks. Fastening is easier because the self-supporting unit requires only a few attachment points and can be installed as a single module.In addition, the number of screw connections in the entire fuel system is significantly reduced.

[0010] The integral, self-supporting unit can preferably be constructed entirely or partially with a die-cast aluminum housing. For example, valve seats and / or channels can be integrated into this housing as gas lines. The openings or cavities required for valve assembly or for the assembly of other components can be closed with seals and covers. The integral, self-supporting unit can also be composed of multiple parts. For example, a sub-unit can be constructed with a die-cast aluminum housing, with additional components attached to this sub-unit. However, according to the invention, there are no bolted, exposed pipes between the parts or components in order not to compromise reliability and ease of assembly.

[0011] In a further embodiment of the invention, the fuel system also includes a second vent valve as an internal component, with both vent valves preferably being connected to a common purge line that leads through the housing to the outside. In particular, one vent valve is arranged upstream of the pressure reducer, and the other vent valve is arranged downstream of the pressure reducer. This allows both the high-pressure and medium-pressure sides to be reliably purged. Furthermore, additional vent valves can also be provided, particularly when using a two-stage pressure reducer.

[0012] It is also advantageous if at least one check valve and a distribution to several tank lines are present as internal components, with the tank lines leading to the outside and with a connection for each pressure tank. The additional integration of the distribution and the check valve on the inlet side into the unit and thus into the fuel system assembly further reduces the assembly and testing effort on the vehicle. The majority of the connection points and screw fittings are therefore arranged internally in the fuel system and have already been assembled and tested before the assembly is installed in the vehicle. It is also advantageous if the tank nozzle is connected directly to the inlet line and is therefore part of the fuel system. This further simplifies assembly in the vehicle.

[0013] Preferably, the pressure reducer can be adjusted to the desired pressure level via a spring load.

[0014] To avoid excessive temperature changes at higher volume flows through the fuel system and during significant pressure changes, it can be advantageous to provide a cooling device on the pressure reducer. The cooling device can preferably be designed as a heat exchanger with fluid-flow channels. These channels can be provided in the common housing or incorporated into it. In particular, this heat exchanger can be designed to be connectable to a vehicle's coolant system.

[0015] In a preferred embodiment, the fuel system additionally comprises an electronic tank control unit, which is attached to and supported by the assembly, wherein the tank control unit is suitable for receiving and processing at least the signals from the sensors present in the fuel system and for generating one or more output signals. By integrating the fuel system of the electronic tank control unit into the fuel system, the assembly can be tested even more extensively in advance, and even fewer interfaces need to be considered during assembly in the vehicle. The wiring harness between the tank control unit and the sensors in the assembly can thus also be integrated and supported by the assembly.

[0016] The tank control unit is further improved if it is configured to receive a temperature sensor signal from each pressure tank, and especially if it can also receive a pressure sensor signal from each pressure tank. This allows the pressure tank fill level to be calculated more accurately and reliably.

[0017] In addition, the tank control unit can be configured to communicate with a hydrogen filling station and, in particular, to control a refueling process.

[0018] In a particularly preferred embodiment, a temperature sensor is present as an internal component. The temperature sensor can be used to monitor the state of the hydrogen and, under certain conditions, to calculate the amount of hydrogen.

[0019] In particular, a simplified design can offer advantages because it is more cost-effective and contains fewer components. In this embodiment according to the invention, the fuel system comprises only one pressure sensor and one temperature sensor as internal sensors, each located upstream of the pressure reducer.

[0020] In a further advantageous embodiment, a second pressure sensor and / or a second temperature sensor are provided as internal components, with one pressure sensor and one temperature sensor preferably being arranged upstream of the pressure reducer, and one pressure sensor and one temperature sensor downstream of the pressure reducer. These additional sensors allow for more precise detection of the conditions of the flowing hydrogen gas, thus making the calculation of the hydrogen quantities more accurate and reliable. Furthermore, malfunctions or leaks can be more easily detected, which increases the safety of the system.

[0021] As an extension, a hydrogen purity sensor can be provided as an internal component. This is preferably located downstream of the pressure reducer in the flow direction. This additional sensor can ensure that, for example, a downstream fuel cell receives sufficient clean hydrogen, thus maintaining the function of the fuel cell and extending its service life. Necessary maintenance or replacement of the gas filter is detected in a timely manner.

[0022] Particularly preferably, the internal components are arranged in the following order in the flow direction from the inlet line to the outlet line: gas filter, pressure reducer, vent valve, overpressure safety valve, shut-off valve. Additional internal components can be arranged between these components, before or after them. This order offers particularly good functionality.

[0023] Likewise, an embodiment of the invention is encompassed in which the structural unit is composed of several sub-units which are fastened to one another in such a way that they form the supporting structural unit.

[0024] In particular, the assembly can comprise a subunit having a housing, preferably made of cast aluminum, in which at least the following internal components are arranged: the pressure reducer, the pressure sensor, the vent valve, the overpressure safety valve, and the shut-off valve. In this context, "arranged" means that for the valves, and especially for the shut-off valve, it is sufficient if at least the valve seat is arranged in the subunit.

[0025] Furthermore, it is advantageous if the assembly has a substantially prism-shaped configuration with two end faces, wherein the end faces are preferably triangular or parallelogram-like. This shape of the assembly allows the fuel system to be accommodated in a space-saving manner between the pressure tanks on the vehicle. The pressure tanks are elongated and cylindrical, so that the assembly, with its triangular or parallelogram-like cross-sectional shape, can be easily arranged in the gaps between the pressure tanks without requiring additional installation space.

[0026] In this context, a triangle-like end face is understood not only to be an exact triangle, but also when the triangle's boundary lines are slightly curved or have individual protrusions or indentations. The decisive factor in this context is that the end faces essentially resemble a triangle. The same applies analogously to parallelogram-like end faces.

[0027] In particular, it is advantageous that the connection for the input line and / or the connection for the output line are each located on one of the end faces. This makes them easily accessible and easy to install and maintain.

[0028] To further simplify assembly, it is advantageous if the assembly includes mounting options that allow the fuel system to be mounted to a support structure that secures the pressure tanks in the vehicle. This allows the fuel system to be attached to a tank module, which includes a support structure and several pressure tanks, and connected to the pressure tank lines in advance. The tank module, including the fuel system, is then installed in the vehicle as a single unit.

[0029] The assembly time in the vehicle manufacturer's production line is thus further minimized, which is a major advantage.

[0030] Further advantageous features of the invention are explained using exemplary embodiments with reference to the drawings. These features can be advantageously implemented not only in the illustrated combination, but also individually combined with one another. The figures show in detail: Fig.1 Schematic representation of a fuel system according to the invention Fig.2a,b Examples of the geometric shape of the housing Fig.3 further fuel system according to the invention

[0031] The figures are described in more detail below. Like reference numerals indicate like or similar parts or components.

[0032] The Fig.1schematically shows an embodiment of a fuel system 1 for a hydrogen-powered vehicle according to the invention. The dimensions and position relative to the pressure tanks 40, 50 are not to scale. In this embodiment, the fuel system 1 is connected via the inlet line 3 to the distributor 19, which connects the tank lines 8, 9 and the tank nozzle 7 to the fuel system 1. Only two pressure tanks 40, 50 are shown as examples, but multiple pressure tanks can also be connected.

[0033] The internal components include the pressure reducer 10, which has a two-stage design, the gas filter 11, the vent valve 13, the overpressure safety valve 14, and the shut-off valve 15 upstream of the outlet line 4. All of these internal components are installed in or on the integral and self-supporting unit 2. The flow direction from the inlet line 3 to the outlet line 4 is designated by 18. A consumer, such as a fuel cell or a gas engine, can be connected to the outlet line 4. Furthermore, at least one pressure sensor 31, 33 and at least one temperature sensor 32, 34 are present as internal components.

[0034] By using the aforementioned internal components and integrating them into a single assembly, the fuel system becomes more reliable. Fuel system 1 as assembly 2 can be pre-assembled and tested for functionality and leaks, allowing it to be assembled during vehicle assembly as a single unit with few interfaces much faster and more reliably than with previous fuel systems. Furthermore, only these few interfaces need to be tested for leaks.

[0035] Several of the internal components can be arranged in a housing as a sub-unit, as shown here. The other components or sub-units are connected to this sub-unit to form the structural unit 2. The housing 5 of the sub-unit is preferably made of cast aluminum. In the illustrated embodiment, this sub-unit comprises the pressure reducer 10, the vent valve 13, the overpressure safety valve 14, and the shut-off valve 15. And optionally pressure and temperature sensors and, if applicable, the cooling device 17, where provided. In particular, the housing 5 can be designed as the base body of the sub-unit, into which the necessary valve seats, openings, or cavities for the sensors, as well as the gas lines, for example as flow-optimized channels, are incorporated.

[0036] The shut-off valve 15 is preferably designed as an electromagnetic valve. The pressure reducer 10 is two-stage and preferably spring-loaded, adjusting it to the desired pressure level. The vent valve 13 has a flushing line that leads through the housing to the outside. It is only indicated in the drawing at valve 13. The vent valve 13 is preferably designed as a manual valve, as it is only required during commissioning or maintenance work.

[0037] The pressure relief valve 15 protects the medium-pressure side of the fuel system, i.e., the area in the flow direction downstream of the pressure reducer 10, against excessive pressure. It leads to a vent line 6 that leads to the outside and to which a hose or other line can be connected externally for the safe discharge of hydrogen gas in an emergency.

[0038] Additionally, this version optionally includes the electronic tank control unit 30, which can be attached to the structural unit 2. Alternatively, the tank control unit can also be arranged as an internal component in the structural unit 2. The tank control unit 30 processes the signals from the internal sensors and additionally the signals from the external sensors, here, for example, the pressure sensors 43, etc. and the temperature sensors 42, etc. on the individual pressure tanks 40, 50. This enables a reliable calculation of the tank fill levels and hydrogen consumption. The tank control unit 30 can output, for example, the tank fill levels, a range, or similar values ​​as output signals. Furthermore, it can communicate with a hydrogen filling station, if necessary, so that the refueling process runs optimally, or it can control the refueling process in communication with the filling station.And the tank control unit is connected to a fuel cell or gas engine to exchange information and signals.

[0039] Additionally, a second pressure sensor 31, 33 and / or a second temperature sensor 32, 34 can be installed as an internal component, as shown. This further improves tank level calculations, communication with a gas station, leak monitoring, and malfunction detection.

[0040] In the area of ​​the pressure reducer 10, a cooling device 17 can be provided, which serves to prevent excessive temperature changes due to the pressure release of the hydrogen at the pressure reducer 10.

[0041] Preferably, the inlet line 3 and the outlet line 4 are provided on opposite end faces 20, 21 of the housing 2. This allows the fuel system 1 to be designed with a slim profile and provides sufficient space for the connections for the tank nozzle 7 and the fuel cell or gas engine.

[0042] In the Fig. 2a and 2bPossible shapes for integral and self-supporting structural units 2, 2.1 are shown in a simplified schematic. The end faces 20, 21 are triangular in one case and parallelogram-like in the other (20.1, 21.1). In both cases, this also includes surfaces with curved edges or with protrusions or indentations, as previously described. The purpose of this shape is to allow the fuel system 1, 1.1 to be arranged between the cylindrical pressure tanks in a space-saving manner. Also shown are the fastening options 22 on each of the side surfaces of the structural unit 2, 2.1. Using the fastening options 22, the fuel system 1, 1.1 can be mounted on a supporting structure that carries the pressure tanks and is attached to the vehicle. In addition to the structural unit shapes shown, other similar shapes are conceivable that are suitable for arranging the fuel system in the gaps between the pressure tanks without requiring additional space.

[0043] The Fig.3 shows a further embodiment of the fuel system 1a according to the invention. The variant shown differs from that shown in Fig.1 The embodiment shown is characterized by the fact that the distributor 19 to the tank lines 8, 9, as well as at least one check valve 16, are additionally arranged as internal components on the structural unit 2a. This results in even fewer interfaces that must be observed and checked during vehicle assembly. In particular, the tank nozzle 7 can be attached directly to the structural unit 2a and supported by it.

[0044] The temperature sensor 34 and / or the pressure sensor 33 can advantageously also be positioned on the distributor 19 in this embodiment.

[0045] As a preferred embodiment, the housing 5 can be manufactured as a base body for the subunit, particularly as a die-cast aluminum component, into which the necessary valve seats, openings or cavities for the sensors, as well as the gas lines, for example, as flow-optimized channels, are incorporated. If it is constructed in multiple parts, it is important that there are no free pipes between the parts. Instead, the parts are directly connected to one another, for example, by screwing.

[0046] For example, only two pressure tanks are shown. Here, too, multiple tank lines and multiple pressure tanks can be connected. List of reference symbols

[0047] 1, 1a, 1.1 Fuel system 2, 2a, 2.1 Integral and self-supporting unit 3, 3a Inlet line 4 Outlet line 5 Housing sub-unit 6 Blow-off line 7 Tank nozzle 8, 9 Tank line 10 Pressure reducer 11 Gas filter 13 Vent valve 14 Overpressure safety valve 15 Shut-off valve 16 Check valve 17 Heating or cooling device 18 Flow direction 19 Distributor 20, 20.1, 21, 21.1 End faces 22 Mounting options 30Tank control unit 31, 33Pressure sensor 32, 34Temperature sensor 40, 50Pressure tank 41, 51Tank valve 42Temperature sensor 43Pressure sensor

Claims

1. Fuel system (1, 1a, 1.1) for installation in a hydrogen-powered vehicle and for one or more hydrogen pressure tanks (40, 50) designed for a high pressure level of at least 200 bar, comprising a connection for an input line (3, 3a), a connection for an output line (4) and at least the following internal components: a pressure reducer (10), a gas filter (11), a shut-off valve (15), a vent valve (13), an overpressure safety valve (14) and a pressure sensor (31, 33); wherein the pressure reducer (10) is designed such that it can reduce the pressure of the hydrogen from the high pressure level from the pressure tank to a medium pressure level of between 3 bar and 30 bar by way of the pressure reducer (10) being designed as a two-stage pressure reducer, wherein the first stage reduces the pressure from the pressure tank to an intermediate level of between 40 and 80 bar and the second stage further reduces the pressure to the medium pressure level, and wherein the internal components and gas lines, which connect these internal components to each other, are arranged in an integral and self-supporting unit (2, 2a, 2.1).

2. Fuel system (1, 1a, 1.1) according to Claim 1, characterized in that it comprises, as internal components, a non-return valve (16) and a distribution system (19) to several tank lines (8, 9), wherein the tank lines (8, 9) lead out of the unit (2, 2a, 2.1) to the outside and a connection is provided for each pressure tank (40, 50).

3. Fuel system (1, 1a, 1.1) according to either of Claims 1 and 2, characterized in that the tank nozzle (7) is part of the unit (2, 2a, 2.1).

4. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that a cooling device (17) is provided on the pressure reducer (10).

5. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that an electronic tank control unit (30) is provided, which is fastened to the unit (2, 2a, 2.1) and is supported by it, wherein the tank control unit is suitable for receiving and for processing the signals from the sensors that are provided and for generating one or more output signals.

6. Fuel system (1, 1a, 1.1) according to Claim 5, characterized in that the tank control unit (30) is configured to receive a temperature sensor signal from each pressure tank (40, 50) and in particular to receive a pressure sensor signal from each pressure tank (40, 50).

7. Fuel system (1, 1a, 1.1) according to either of Claims 5 and 6, characterized in that the tank control unit (30) is configured such that it can communicate with a hydrogen fueling station and in particular can control a fueling process.

8. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that a temperature sensor (32, 34) is provided as an internal component, wherein preferably only one pressure sensor (33) and one temperature sensor (34), in each case arranged upstream of the pressure reducer (10), are provided as internal sensors.

9. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that it comprises, as internal components, a further second pressure sensor (31, 33) and / or a further second temperature sensor (32, 34), wherein preferably a pressure sensor (33) and a temperature sensor (34) are arranged upstream of the pressure reducer (10) and a pressure sensor (31) and a temperature sensor (32) are arranged downstream of the pressure reducer (10).

10. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that it comprises, as an internal component, a hydrogen-purity sensor.

11. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that the internal components are arranged in the following order from the input line (3) to the output line (4) in the throughflow direction (18): gas filter (11), pressure reducer (10), vent valve (13), safety valve (14), shut-off valve (15).

12. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that the unit (2, 2a, 2.1) is composed of several subunits, which are fastened to one another such that they form a self-supporting unit.

13. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that the unit (2, 2a, 2.1) comprises a sub-unit, which has a housing (5), preferably composed of a cast aluminum material, in which at least the following internal components are arranged: the pressure reducer (10), the pressure sensor (31, 33), the vent valve (13), the overpressure safety valve (14) and the shut-off valve (15).

14. Fuel system (1, 1a, 1.1) according to any of the preceding claims, characterized in that the unit (2, 2a, 2.1) has fastening options (22) by means of which the fuel system (1, 1a, 1.1) can be fitted to a supporting structure, which fastens the pressure tanks in the vehicle.