Tank system and method for testing an isolating valve in a tank system

Abstract

Disclosed is a method for testing a switchable isolating valve of a valve device that connects a tank vessel to a pipe system, wherein a gas is stored at a first pressure in the tank vessel, and a second pressure that is lower than the first pressure prevails in the pipe system. The method comprises: actuating the isolating valve in order to switch it from a closed position, in which the isolating valve closes an extraction path of the valve device, which extraction path connects the pipe system and the tank vessel, into an open position, in which the isolating valve opens the extraction path; detecting a pressure profile in a tank-side portion of the extraction path which extends between the tank vessel and the isolating valve; determining whether the pressure profile detected after the actuation of the isolating valve includes a pressure drop; and outputting a fault signal if it is determined that the pressure profile detected after the actuation of the isolating valve does not include a pressure drop.

Description

[0001] Description

[0002] title

[0003] Tank system and method for testing a isolation valve in a tank system

[0004] Technical area

[0005] The present invention relates to a tank system, in particular a tank system for storing a gaseous fuel, such as hydrogen, and for supplying a consumer system with the gaseous fuel, as well as a method for testing an isolating valve in a tank system.

[0006] State of the art

[0007] Hydrogen and other gaseous fuels can be used in mobile applications, particularly in road vehicles, to operate propulsion systems. This includes the operation of fuel cells as well as internal combustion engines or other heat engines. Gaseous fuels can also be advantageously used to generate energy in stationary applications. Typically, the gas is stored in a tank system with one or more tank containers and fed to the consumer system, e.g., a fuel cell or internal combustion engine, via a piping system connected to the tank container(s).

[0008] US 7367349 B2 describes a supply system for a fuel cell in which several tanks are connected in parallel, each via a withdrawal line, to a line system for supplying the fuel cell. A switchable isolating valve is arranged in each withdrawal line to connect or disconnect the respective tank from the line system. When the system is started, only one of the isolating valves is opened initially to increase the pressure in the line system, and then the remaining valves are opened. This serves the purpose of reducing wear on the valves by reducing the pressure difference between the tanks and the high-pressure line system at the time the remaining valves open.

[0009] In general, it is desirable for the isolation valves to open reliably upon system start-up to increase operational reliability. This applies to both single-tank and multi-tank systems.

[0010] Disclosure of the invention

[0011] Against this background, the present invention provides a method having the features of claim 1 and a tank system having the features of claim 8.

[0012] According to a first aspect of the invention, a method is provided for testing a switchable isolating valve of a valve device which connects a tank container to a line system, wherein a gas having a first pressure is stored in the tank container and a second pressure which is lower than the first pressure is present in the line system.The method comprises controlling the isolating valve in order to switch it from a closed position, in which the isolating valve closes a withdrawal path of the valve device connecting the line system and the tank container, to an open position in which the isolating valve opens the withdrawal path, detecting a pressure profile in a tank-side section of the withdrawal path which extends between the tank container and the isolating valve, determining whether the detected pressure profile includes a pressure drop after the isolating valve has been activated, and outputting an error signal if it is determined that the detected pressure profile does not include a pressure drop after the isolating valve has been activated.

[0013] According to a second aspect of the invention, a tank system comprises at least one tank container for storing gas, in particular hydrogen, a line system for supplying a consumer system, such asa fuel cell or a heat engine, a valve device with a withdrawal path which connects the tank container and the line system, and a switchable isolating valve arranged in the withdrawal path, which is switchable between a closed position in which it closes the withdrawal path, and an open position in which it opens the withdrawal path, a pressure sensor which is connected to a tank-side section of the withdrawal path which extends between the tank container and the isolating valve and is designed to detect the pressure in the tank-side section of the withdrawal path, and a control device which is signal-connected to the valve device and the pressure sensor and is designed to cause the tank system to carry out the steps of a method according to one of the preceding claims.

[0014] One idea underlying the invention is to record a pressure curve on the tank side of the isolation valve and to evaluate it after the valve has been activated. Since the pressure in the piping system before the isolation valve opens is lower than in the tank container and thus on the tank side of the isolation valve, the opening of the isolation valve leads to a brief pressure drop on the tank side. This means that in a tank-side section of a withdrawal path of the valve device, an undershoot in the pressure curve occurs when the isolation valve switches from its closed position to its open position. This brief pressure drop can be determined or detected by a control device in the pressure signal supplied by the pressure sensor. If such a pressure drop is detected, it can be concluded that the respective isolation valve has opened correctly.If no pressure drop is detected, it can be concluded that the isolation valve was not switched from the closed position to the open position as a result of the control.

[0015] An advantage of the invention is that a non-switching isolation valve can be reliably detected.

[0016] Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figures of the drawing. According to some embodiments, it can be provided that the actuation of the isolating valve comprises generating a first opening force for opening the isolating valve, wherein, if it is determined that the detected pressure curve after the actuation of the isolating valve does not contain a pressure drop, the isolating valve is actuated again with a second opening force that is greater than the first opening force, wherein the steps of detecting the pressure curve and determining are carried out again. Accordingly, if it is determined during the first actuation of the isolating valve that it does not open, the isolating valve can be actuated again, specifically with an increased opening force.This can further increase operational safety, as the tank system can remain fully functional if the isolation valve can be opened with the increased opening force.

[0017] According to some embodiments, the error signal can be output only if it is again determined that the detected pressure curve does not include a pressure drop after the isolation valve is actuated again with the second opening force. Optionally, a first error signal can be output if a pressure drop is not detected in the detected pressure curve after the isolation valve is actuated for the first time, and a second error signal can be output if it is again determined that the detected pressure curve does not include a pressure drop after the isolation valve is actuated again with the second opening force.

[0018] According to some embodiments, it can be provided that the isolating valve is designed as an electrically controllable, normally closed solenoid valve, wherein the generation of the first opening force comprises energizing the isolating valve with a first control current, and wherein the generation of the second opening force comprises energizing the isolating valve with a second control current that is greater than the first control current.

[0019] According to some embodiments, it may be provided that an enable signal is output when it is determined that the detected pressure curve after the activation of the isolation valve contains a pressure drop. For example, outputting the enable signal may include generating an enable message and writing the enable message to a data memory.

[0020] According to some embodiments, it can be provided that a plurality of tank containers are connected to the line system via a plurality of valve devices, each of which has a switchable isolating valve, wherein each isolating valve is controlled in order to switch it from the closed position to the open position, wherein a pressure profile in the tank-side section of the withdrawal path is detected by each isolating valve after the respective isolating valve has been controlled, wherein the determination of whether the detected pressure profile after the respective isolating valve has been controlled includes a pressure drop is carried out for each isolating valve, and wherein the output of the error signal is carried out for each isolating valve for which it is determined that the respective detected pressure profile after the respective isolating valve has been controlled does not include a pressure drop. In particular, with a plurality of tank containers, it can lead to undesirable effects if one of the isolating valves does not open.On the one hand, the gas stored in the tank whose isolation valve does not open is not available for the consumer system. On the other hand, this results in uneven emptying of the tanks. If the isolation valve does open at a later time, e.g., during a system restart, this leads to pressure equalization and / or backfilling of the other tanks. Such situations can be reliably avoided using this method.

[0021] According to some embodiments, it can be provided that the isolation valves are controlled sequentially or simultaneously.

[0022] According to some embodiments, it can be provided that determining whether the detected pressure curve after actuation of the isolation valve contains a pressure drop comprises determining a pressure gradient of the detected pressure curve, and a pressure drop is determined if the pressure gradient assumes values ​​less than zero within a predetermined period of time after actuation. According to some embodiments, it can be provided that outputting the error signal comprises generating an error message and writing the error message to a data memory. Alternatively or additionally, it can be provided that outputting the error signal comprises outputting a warning signal to a user interface. For example, an optical signal can be output on a display device or a warning light of the user interface, or an acoustic or haptic signal can be output.

[0023] According to some embodiments, it can be provided that the isolating valve is designed as an electrically controllable, normally closed solenoid valve.

[0024] According to some embodiments, it can be provided that the tank system has a plurality of tank containers which are connected to the line system via a plurality of valve devices, each of which has a switchable isolating valve.

[0025] The features and advantages disclosed herein in connection with one aspect of the invention are also disclosed for the other aspect.

[0026] The invention is explained below with reference to the figures of the drawings. The figures show:

[0027] Fig. 1 is a schematic view of a hydraulic circuit diagram of a tank system according to an embodiment of the invention;

[0028] Fig. 2 is a detailed view of a valve device of a tank system according to an embodiment of the invention; and

[0029] Fig. 3 shows the sequence of a method according to an embodiment of the invention.

[0030] In the figures, the same reference numerals designate identical or functionally equivalent components, unless otherwise stated. Fig. 1 schematically shows a tank system 100 for supplying a consumer system 200 with a gaseous fuel, e.g., hydrogen. The consumer system 200 can be, for example, a fuel cell or a heat engine. The tank system 100 can be used, for example, in a mobile application, such as a vehicle. However, the invention is not limited thereto.

[0031] As shown by way of example in Fig. 1, the tank system 100 has a plurality of tank containers 1, a line system 2, a plurality of valve devices 3 and a control device 5. Optionally, a user interface 6 can also be provided. In Fig. 1, a tank system 100 with three tank containers 1 is shown purely by way of example. It is also conceivable for the tank system 100 to have only one tank container 1 or a number other than three tank containers 1. Furthermore, Fig. 1 shows by way of example that a valve device 3 is provided for each tank container 1, via which valve device 3 the respective tank container 1 is connected to the line system 2. Alternatively, it is also conceivable for a plurality of tank containers 1 to be connected to the line system 2 via a common valve device 3.

[0032] The tank containers 1 generally define an internal volume and can, for example, be designed to store hydrogen at a nominal pressure of up to 700 bar.

[0033] The piping system 2 can, for example, be a high-pressure piping system 2, which is connected to the consumer system 2 via an optional medium-pressure piping system 7, which is shown only symbolically as a block in Fig. 1. As schematically shown in Fig. 1, the tanks 1 are connected to the piping system 2 in parallel.

[0034] The valve devices 3 are assigned to the respective tank 1 and connect it to the line system 2. Fig. 2 shows a schematic and highly simplified example of the structure of the valve device 3. As shown in Fig. 2, the valve device 3 has a first internal connection 3A, which is connected to the internal volume of the tank 1, and an external connection 3C, which is connected to the line system 2. Furthermore, a second internal connection 3B can optionally be provided. The valve device 3 has, as shown in Fig. 2, a switchable isolating valve 30 and a pressure sensor 4. Optionally, a check valve 33 can also be provided. Likewise optionally, the valve device 3 can have a temperature sensor 35, as shown in Fig. 2 purely as an example.

[0035] The first internal connection 3A and the external connection 3C are connected to one another by a withdrawal path 31, in which the isolation valve 30, e.g. in the form of an electrically switchable, normally closed solenoid valve, is arranged. The isolation valve 30 divides the withdrawal path 31 into a tank-side section 31A, which extends between the first internal connection 3A and the isolation valve 30, and a line-side section 31B, which extends between the isolation valve 30 and the external connection 3C. The isolation valve 30 can be switched between a closed position and an open position. In Fig. 2, the isolation valve 30 is shown in the closed position. In this, it closes the extraction path, i.e., it interrupts the fluidic connection of the tank-side and the line-side section 31 A, 31 B of the extraction path 31 and thus prevents gas from flowing out of the tank container 1 from the first internal connection 3A to the external connection 3C.In the open position, the isolating valve 30 opens the extraction path, i.e., it establishes a fluidically conductive connection between the tank-side and the line-side sections 31A, 31B of the extraction path 31 and allows a flow of gas from the tank container 1 from the first internal connection 3A to the external connection 3C.

[0036] As further shown in Fig. 2, the second internal connection 3B can be connected to the external connection 3C by a filling path 32. The optional check valve 33 is arranged in the filling path 32 and designed such that it only permits flow from the external connection 3C to the second internal connection 3B. If the pressure in the line system 2 is higher than in the tank container 1, gas from the line system 2 can flow from the external connection 3C via the second internal connection 3B into the tank container 1, even when the isolating valve 30 is closed. As further shown in Fig. 2, the pressure sensor 4 is connected to the tank-side section 31A of the withdrawal path 31. The pressure in the tank-side section 31A of the withdrawal path 31A can thus be detected by means of the pressure sensor 4.

[0037] The optional temperature sensor 35 can be part of the valve device 3, as shown purely by way of example in Fig. 2. The temperature sensor 35 is arranged such that it is connected to the internal volume of the tank container 1. The temperature sensor 35 can thus measure a temperature in the tank container 1.

[0038] The control device 5 is shown in Fig. 1 merely as a block and can in particular be an electronic control device 5. The control device 5 can, for example, have a processor 50 and a data memory 51. The processor 50 can be implemented, for example, as a CPU, as an FPGA, as an ASIC or the like. The data memory 51 can in particular be a non-volatile data memory, e.g., a flash memory, an SD memory, a hard disk or the like. The data memory 51 can be read by the processor 50 and can, for example, store software that can be executed by the processor 50 and causes it to generate output signals, e.g., in the form of control signals, based on input signals, e.g., in the form of measured values. The control device 5 is signal-connected to the valve devices 3 and the respective pressure sensor 4, e.g., wired via a data bus, such as a CAN bus, USB or the like, or wirelessly, e.g.,via WiFi, Bluetooth or similar.

[0039] In particular, the control device 5 can be designed to cause the tank system 100 to execute a method M for testing the switchable isolating valve 30 of the respective valve device 3. The sequence of a method M for testing the switchable isolating valve 30 of the respective valve device 3 is shown schematically in Fig. 3. The method M is based on an initial situation in which a gas, e.g. hydrogen, is stored at a first pressure in the tank container 1, and a second pressure that is lower than the first pressure exists in the line system 2. The isolating valves 30 are closed in this case. Such an initial situation can exist, for example, before the consumer system 200 connected to the tank system 100 is started or powered up. The method M is explained below with reference to the tank system 100 described above.

[0040] In a first step M1, the isolation valve 30 is controlled M1 by means of the control device 5, e.g. by the control device 5 outputting a control signal to the isolation valve 30 in order to switch it from its closed position to its open position. The control signal can in particular cause a first opening force to be generated to open the isolation valve 30. If the isolation valve 30, as shown by way of example in Fig. 2, is designed as an electrically controllable, normally closed solenoid valve, the generation of the first opening force can comprise energizing the isolation valve 30 with a first control current. If, as shown by way of example in Fig. 1, a plurality of tank containers 1 with a plurality of valve devices 3 are provided, the isolation valves 30 of the various valve devices 3 can be controlled successively or simultaneously.

[0041] In step M2, the pressure in the tank-side section 31A of the removal path 31 in magazines is detected by means of the pressure sensor 4. The control device 5 thus receives a pressure signal representing a pressure curve.

[0042] In step M3, the control device 5 determines whether the recorded pressure curve after the activation (step M1) of the isolation valve 30 contains a pressure drop. The control device 5 thus evaluates the pressure signals recorded since the activation of the isolation valve 30 and checks whether the pressure signals indicate a pressure drop, at least for a limited time. For example, the control device 5 can determine a pressure gradient of the recorded pressure curve, with a pressure drop being determined or detected if the pressure gradient assumes values ​​less than zero within a predetermined period of time after the activation.

[0043] If it is determined in step M3 that the recorded pressure curve after activation M1 of the isolating valve 30 contains a pressure drop, as shown in Fig. 3 by the "+" symbol, the method can proceed to step M5. The presence of a pressure drop indicates that the respective isolating valve 30 was opened upon activation (step M1). As a result of the pressure in the line system 2 being lower than the pressure in the tank container 1, a pressure drop occurs after the opening of the isolating valve 30, which pressure drop is generally limited in time. The pressure curve thus contains a type of undershoot.

[0044] In step M5, the control device 5 can, for example, output an enable signal. This can include, for example, generating an enable message and writing the enable message to the data memory 51.

[0045] If it is determined in step M3 that the recorded pressure curve after actuation (step M1) of the isolating valve 30 does not include a pressure drop, as represented by the symbol in Fig. 3, the method M can proceed directly to step M4, in which the control device 5 outputs an error signal. Outputting the error signal can, for example, comprise generating an error message and writing the error message to the data memory 51. Alternatively or additionally, the control device 5 can also output a warning signal to the user interface 6. For example, the user interface 6, which is represented only symbolically as a block in Fig. 1, can have a display device or a warning light, which is caused by the control device 5 to output a visual signal, or an acoustic or haptic warning signal can be output at the user interface 6.The error signal can be output for each isolation valve 30 for which it is determined that a pressure drop is not included in the respective detected pressure curve after the activation (step M1) of the respective isolation valve 30, e.g. together with an index of the respective isolation valve.

[0046] Optionally, if it is determined in step M3 that the recorded pressure curve after actuation (step M1) of the isolation valve 30 does not include a pressure drop, method M can initially proceed to step M31. In step M31, the control device 5 can increment a counter value by one, which indicates how often the isolation valve 30 has been actuated since the last closing of the isolation valve 30 to switch it from the closed position to the open position. When the isolation valve 30 is switched to its closed position, the counter value is set to zero.

[0047] In step M32, the control device 5 checks whether the count value is less than a predetermined limit value. The limit value can be, for example, an integer between two and ten. If it is determined in step M32 that the counter value is less than the limit value, as represented in Fig. 3 by the symbol "+", the method can go back to step M1. In this case, the isolating valve 30 is controlled again by the control device 5, wherein the renewed control of the isolating valve 30 takes place with a second opening force that is greater than the first opening force. For example, generating the second opening force can comprise energizing the isolating valve 30 with a second control current that is greater than the first control current. Steps M2 and M3 are then repeated as described above.If it is determined in step M3 that the recorded pressure curve after the renewed actuation of the isolating valve 30 with the second opening force contains a pressure drop (symbol "+" in Fig. 3), the method proceeds to step M5. Otherwise, i.e. if it is determined that the recorded pressure curve after the renewed actuation of the isolating valve with the second opening force does not contain a pressure drop, steps M31 and M32 follow. As long as it is determined in step M32 that the count value is less than the limit value (symbol "+"), steps M1 - M3 can again follow, whereby the opening force can optionally be increased further with each iteration. If it is determined in step M32 that the count value reaches the limit value (symbol ), the method proceeds to step M4.

[0048] Optionally, the error signal is output in step M4 only if it is determined again at least once that the recorded pressure curve does not contain a pressure drop after the isolation valve has been actuated again with the second opening force.

[0049] Alternatively, step M4 may be executed each time it is determined in step M3 that the detected pressure curve after the renewed actuation of the isolation valve 30 does not contain a pressure drop, while additionally performing steps M31 and M32. For example, a first error signal may be output in step M4 each time it is determined in step M32 that the count value is less than the limit value. If it is determined in step M32 that the count value reaches the limit value (symbol A second error signal can be output in step M4. The output of the first error signal can, for example, only involve the generation and writing of a

[0050] Error message in the data memory 51, while the output of the second error signal may alternatively or additionally comprise output of a warning signal at the user interface. Although the present invention has been described above with reference to

[0051] Although the above-mentioned exemplary embodiments have been explained by way of example, it is not limited to these, but can be modified in a variety of ways. In particular, combinations of the above exemplary embodiments are also conceivable.

Claims

Claims 1. Method (M) for testing a switchable isolating valve (30) of a valve device (3) which connects a tank container (1) to a line system (2), wherein a gas having a first pressure is stored in the tank container (1), and a second pressure which is lower than the first pressure is present in the line system (2), the method (M) comprising: Controlling (M1) the isolating valve (30) in order to switch it from a closed position, in which the isolating valve (30) closes a removal path (31) of the valve device (3) connecting the line system (2) and the tank container (1), to an open position in which the isolating valve (30) opens the removal path (31); Detecting (M2) a pressure curve in a tank-side section (31 A) of the withdrawal path (31) extending between the tank container (1) and the isolation valve (30); Determining (M3) whether the detected pressure curve after the activation (M1) of the isolating valve (31) contains a pressure drop; and Outputting (M4) an error signal if it is determined that the detected pressure curve after the activation (M1) of the isolating valve (31) does not contain a pressure drop.

2. Method (M) according to claim 1, wherein the actuation (M1) of the isolating valve (30) comprises generating a first opening force for opening the isolating valve (30), wherein, if it is determined that a pressure drop is not included in the detected pressure profile after the actuation (M1) of the isolating valve (31), a renewed actuation (M1) of the isolating valve (30) takes place with a second opening force which is greater than the first opening force, wherein the steps of detecting (M2) the pressure profile and determining (M3) are carried out again, and wherein the output (M4) of the error signal preferably only occurs when it is again determined that the detected pressure curve does not contain a pressure drop after the isolation valve has been actuated again with the second opening force. Method (M) according to claim 2, wherein the isolation valve (30) is designed as an electrically actuable, normally closed solenoid valve, wherein the generation of the first opening force comprises energizing the isolation valve (30) with a first control current, and wherein the generation of the second opening force comprises energizing the isolation valve (30) with a second control current that is greater than the first control current. Method (M) according to one of the preceding claims, additionally comprising: Outputting (M5) an enable signal when it is determined that the detected pressure curve contains a pressure drop after the activation (M1) of the isolating valve (30).Method (M) according to one of the preceding claims, wherein a plurality of tank containers (1) are connected to the line system (2) via a plurality of valve devices (3), each of which has a switchable isolating valve (30), wherein each isolating valve (3) is controlled in order to switch it from the closed position to the open position, wherein a pressure profile in the tank-side section (31A) of the withdrawal path (31) is detected by each isolating valve (30) after the respective isolating valve (30) has been controlled, wherein the determination (M3) of whether the detected pressure profile after the control (M1) of the isolating valve (30) contains a pressure drop is carried out for each isolating valve (30), and wherein the output (M4) of the error signal is carried out for each isolating valve (30) for which it is determined that the respective detected pressure profile after the control (M1) of the respective isolating valve (30) does not contain a pressure drop.Method (M) according to claim 5, wherein the isolation valves (30) are controlled sequentially or simultaneously. Method (M) according to one of the preceding claims, wherein the outputting (M4) of the error signal comprises generating an error message and writing the error message to a data memory (51) and / or outputting a warning signal to a user interface (6). Tank system (100), comprising: at least one tank container (1) for storing gas, in particular hydrogen; a line system (2) for supplying a consumer system (200); a valve device (3) with a withdrawal path (31) connecting the tank container (1) and the line system (2), and a switchable isolating valve (30) arranged in the withdrawal path (31), which is switchable between a closed position, in which it closes the withdrawal path (31), and an open position, in which it opens the withdrawal path (31);a pressure sensor (4) connected to a tank-side section (31A) of the withdrawal path (31), which extends between the tank container (1) and the isolating valve (30), and configured to detect the pressure in the tank-side section (31A) of the withdrawal path (31A); and a control device (5) signal-connected to the valve device (3) and the pressure sensor (4) and configured to cause the tank system (100) to carry out the steps of a method (M) according to one of the preceding claims. The tank system (100) according to claim 8, wherein the isolating valve (30) is designed as an electrically controllable, normally closed solenoid valve. The tank system (100) according to claim 8 or 9, wherein the tank system (100) comprises a plurality of tank containers (1) connected to the line system (2) via a plurality of valve devices (3), each of which has a switchable isolating valve (30).

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