Method and system for detecting fault in fuel cell system

Abstract

The invention relates to a method for detecting a malfunction of a valve assembly (16) in a tank system (11) for a fuel cell system (10), the tank system (11) comprising a plurality of fuel tanks (12, 13, 14), a fuel line assembly (15) for guiding fuel from the fuel tanks (12, 13, 14), and a valve assembly (16) which has a respective discharge valve (17, 18, 19) for each fuel tank (12, 13, 14), the invention relates to a method for conducting fuel from fuel tanks (12, 13, 14) through a fuel line arrangement (15) in a controlled manner, comprising the following steps: ascertaining a temperature gradient with respect to the temperature in each fuel tank (12, 13, 14) during operation of the fuel cell system (10); comparing the determined temperature gradients with each other and / or comparing the determined temperature gradients with the provided at least one target temperature gradient; and detecting a fault of the valve assembly (16) based on the comparison. The invention also relates to a tank system (11) and a computer program product (23) for carrying out the method according to the invention. The invention also relates to a computer-readable storage medium (24) on which a computer program product (23) according to the invention is stored.

Description

Technical Field

[0001] The invention relates to a method and a system for detecting faults in a fuel cell system and in particular in a tank system of a fuel cell system. The invention also relates to a computer program product for executing such a method and to a computer-readable storage medium on which such a computer program product is stored. Background Art

[0002] Fuel cell systems often have complex tank systems. For example, DE 10 2017 212 485 A1 describes a system for storing fuel in a tank system for a vehicle, wherein the tank system comprises a tubular tank container and a high-pressure fuel distributor with integrated regulation and safety technology. The tank container is made of metal and is modularly connected to the high-pressure fuel distributor with integrated regulation and safety technology in a flexible geometry to form a module.

[0003] During driving operation, the tank container should be protected as well as possible from mechanical and / or thermal loads such as vibrations, braking or acceleration. This also applies to the protection of the tank container in the event of an accident. In addition, it is desirable to continuously monitor the tank system in order to detect possible faults in the tank system as early as possible. This is always a challenge when using multiple tank containers. Summary of the invention

[0004] Within the scope of the present invention, a method and a system for detecting faults in a tank system of a fuel cell system are proposed. In particular, a method according to claim 1, a tank system according to claim 7, a computer program product according to claim 9 and a computer-readable storage medium according to claim 10 are proposed. Further embodiments of the invention are derived from the dependent claims, the description and the drawings. In this case, the features described in connection with the method also apply to the tank system according to the invention, the computer program product according to the invention, the storage medium according to the invention and vice versa, so that the disclosures concerning the various aspects of the invention are always mutually referenced or can be mutually referenced.

[0005] According to a first aspect of the present invention, a method for detecting a fault of a valve assembly in a tank system, which is particularly used in a fuel cell system, is provided. The tank system comprises a plurality of fuel tanks, a fuel line assembly for guiding fuel from the fuel tanks, and a valve assembly, wherein the valve assembly has a discharge valve for each fuel tank, respectively, for guiding fuel from the fuel tank through the fuel line assembly in a controlled manner. The method comprises the following steps:

[0006] - determining a temperature gradient during operation of the fuel cell system with respect to the temperature in the individual fuel tanks;

[0007] - comparing the determined temperature gradients with one another and / or with at least one provided target temperature gradient; and

[0008] - Detecting malfunctions of the valve assembly based on these comparisons.

[0009] It has been found within the scope of the present invention that convincing conclusions about possible faults of the valve assembly can be derived in a relatively simple manner based on the temperature gradient in the fuel tank that can be determined. Based on the comparison according to the invention or the comparison according to the invention, a fault can be detected in particular as follows, that is, it is recognized that the outlet valve cannot be switched and / or cannot be opened, especially during normal operation of the fuel cell system, for example during the removal of mass and / or fuel from the fuel tank. Therefore, a fault can be understood as an inability of the outlet valve to switch and / or cannot be opened. If the inability to switch and / or cannot be opened is recognized, corresponding countermeasures can be taken to deal with problems that may arise from this. In particular, the operation of the fuel cell system or the tank system can be prevented when one of the outlet valves is accidentally closed, whereby the associated fuel tank will or may not be emptied as desired.

[0010] In the context of the method, it is also possible to initiate predetermined measures based on the detected and / or displayed faults. That is, if the fault and / or at least one fault is detected, at least one predetermined measure can be initiated. A measure can be understood as the emission of an optical and / or acoustic warning signal. The warning signal can be emitted in a manner that can be perceived acoustically and / or optically for a user of the tank system and / or the fuel cell system (for example in the form of a driver of a vehicle with the fuel cell system).

[0011] The fault can be detected and then displayed. The display of the fault can be understood as the previously described output of a warning signal. Furthermore, the display of the fault can also be understood as the generation of a warning signal stored in a memory, from which a specialist can read the warning signal, for example, when checking the tank system. From the read warning signal, it can be inferred that a fault may have occurred or still exists. Measures can then be taken in order to at least avoid the fault in the future.

[0012] Providing the target temperature gradient can be understood as reading the target temperature gradient from a memory and providing it for comparison, or first calculating it and then providing it for comparison. That is, providing can also be understood as determining and / or calculating the target temperature gradient.

[0013] The outlet valve may be understood as a tank valve which is respectively mounted directly or substantially directly on the fuel tank. The fuel tank may preferably be understood as a hydrogen tank. The detection and possible display of a fault of the valve assembly based on the comparison may be understood as being able to detect and display at least one fault based on the comparison or based on a corresponding comparison result. That is, the comparison result may be correspondingly evaluated and / or taken into account in appropriate calculations for the detection and display of the fault. The method may be performed in particular for detecting a fault of a valve assembly in a fuel cell system of a vehicle, in particular during operation of the fuel cell system in the vehicle.

[0014] Preferably, after the electrical activation of the outlet valve, in particular when starting the fuel cell system and / or during the operation of the fuel cell system, the temperature gradient is determined. The temperature gradient can be determined by means of a suitable measuring sensor and a computing unit connected to the measuring sensor signal. The measuring sensor can have a temperature sensor for determining the temperature gradient.

[0015] In the method according to the invention, the outlet valves can all be electrically actuated simultaneously or substantially simultaneously. In particular, the outlet valves can be actuated in parallel during startup of the fuel cell system or during operation of the fuel cell system. Electrical actuation can be understood as meaning that, whenever possible, the outlet valves are actuated into a release state for conducting fuel from the corresponding fuel tank into the fuel line assembly.

[0016] Before carrying out the comparison according to the invention, it can be determined whether a predetermined temperature increase occurs after the previously described electrical activation of the outlet valves in one or more fuel tanks, or whether the determined temperature increase exceeds a predetermined limit value. If this is the case, it can be inferred that at least one pressure-unbalanced fuel tank and the associated backfilling are present. For example, the comparison and / or the detection according to the invention can only be carried out if no fuel tank has a predetermined temperature change or the determined temperature change is respectively below a predetermined limit value.

[0017] Comparing the temperature gradients determined respectively with each other can be understood as comparing the temperature gradients determined for each fuel tank in pairs or relative to each other. It is also possible to compare all the determined temperature gradients with each other. Comparing each determined temperature gradient with at least one provided target temperature gradient can be understood as comparing each determined temperature gradient with the corresponding target temperature gradient, wherein, in particular in the case of the same fuel tank, the target temperature gradients can be the same respectively, and in particular in the case of different fuel tanks, the target temperature gradients can be different.

[0018] The method can be carried out not only for detecting faults of valve assemblies in tank systems for fuel cell systems, but also in principle for alternative tank systems of chemical and / or electrochemical energy converters.

[0019] According to another embodiment of the present invention, the temperature gradients determined are compared in pairs when comparing, wherein if the difference between the smaller temperature gradient determined for the first fuel tank and the larger temperature gradient determined for the second fuel tank is greater than a predetermined limit difference, a fault is detected in or on the outlet valve for the first fuel tank. In this way, the fault can be quickly and uncomplicatedly determined. The calculation, provision and / or use of additional reference values ​​and / or thresholds can be eliminated. Within the scope of this method, the individual temperature gradients of the temperature in the fuel tank can be first determined. Subsequently, the temperature gradients of different fuel tanks with the same or at least similar geometry and thus similar cooling curves can be compared in pairs. Subsequently, the difference between the temperature gradients compared in pairs can be determined. If the difference is greater than a predetermined threshold or limit difference, it can be inferred that the outlet valve for the fuel tank with a lower degree of cooling, that is, for the fuel tank with a smaller negative temperature gradient, has a fault, especially cannot be opened. If, after the pairwise comparison of all temperature gradients, at least one difference is greater than a predetermined threshold value or limit difference, it can be concluded that the outlet valve for the least cooled fuel tank, i.e., for the fuel tank with the smallest negative temperature gradient, is faulty, in particular cannot be opened. A difference can be understood as a gradient difference. In the pairwise comparison, if the tank system has three fuel tanks, for example, the temperature gradient of the first fuel tank can be compared with the temperature gradient of the second fuel tank, the temperature gradient of the first fuel tank can be compared with the temperature gradient of the third fuel tank, and the temperature gradient of the second fuel tank can be compared with the temperature gradient of the third fuel tank.

[0020] Furthermore, it is possible that in the method according to the invention, the limit difference is predetermined as a function of the temperature in the respective fuel tank and / or as a function of the ambient temperature around the fuel tank. In this way, the limit difference can always be provided relatively accurately and / or correspondingly suitable for the comparison or detection according to the invention in different operating and / or functional states of the fuel cell system. The limit difference can also be predetermined as a function of or taking into account the installation position of the fuel tank in the tank system, in the fuel cell system and / or in the vehicle in which the fuel cell system can be positioned. The temperature in the fuel tank and the ambient temperature can be determined by means of suitable temperature sensors and then provided for calculating or predetermining the limit difference.

[0021] According to another embodiment of the present invention, the temperature gradients obtained are compared individually with the corresponding predetermined target temperature gradients during the comparison, wherein if the temperature gradient obtained for a certain fuel tank is less than the corresponding target temperature gradient, a fault is detected in and / or on the discharge valve for the determined fuel tank. In this way, it is possible to cancel the comparison of the obtained temperature gradients with each other. Nevertheless, it is still possible to reliably identify the prompt for possible faults. The same target temperature gradient can be used for multiple comparisons. Similarly, if the tank system has different fuel tanks, i.e., fuel tanks of different shapes, different sizes and / or different functions, different target temperature gradients are used. If the temperature gradient obtained for a certain fuel tank is less than the corresponding target temperature gradient, it can be understood that the cooling rate or negative gradient of the tank contents of the fuel tank is slower than the target cooling rate with an allowable tolerance deviation or threshold.

[0022] In the method according to the invention, the target temperature gradient or at least one target temperature gradient can be predetermined as a function of the gas pressure in the respective fuel tank, as a function of the temperature in the respective fuel tank and / or as a function of the ambient temperature around the fuel tank. The gas pressure in the respective fuel tank, the temperature in the respective fuel tank and the ambient temperature around the fuel tank can be measured by means of suitable measuring sensors and provided and / or used to predetermine the respective target temperature gradient. In this way, the target temperature gradient is calculated as a function of the current operating state of the tank system, as a function of the functional state of the tank system and / or as a function of the ambient conditions around the tank system. Thus, the target temperature gradient can always be provided relatively accurately or particularly suitable for comparison in different operating and / or functional states.

[0023] Furthermore, in the method according to the invention, it is possible that if a fault is detected and the outlet valve is electrically actuated with a higher current than before the fault was detected, the main method steps of the invention are repeated. That is, if a fault is identified, an alternative reaction is carried out, so to speak, for repeated attempts to open the outlet valve with an increased pull-in current. Depending on whether the opening is successful or not, the type and / or severity of the fault can be inferred. That is, the type and / or severity of the fault can thus also be detected and displayed more accurately. For repeated attempts to open, the outlet valve can be actuated or energized accordingly, in particular, with the maximum permissible pull-in current.

[0024] Another aspect of the invention relates to a tank system for a fuel cell system, the tank system having a plurality of fuel tanks, a fuel line assembly for conducting fuel from the fuel tanks, and a valve assembly, the valve assembly having a discharge valve for each fuel tank, for conducting fuel from the fuel tank through the fuel line assembly in a controlled manner. The tank system comprises a determination unit for determining a temperature gradient with respect to the temperature in each fuel tank during operation of the fuel cell system; and a calculation unit for comparing the determined temperature gradients with each other and / or with at least one provided target temperature gradient, and detecting a fault of the valve assembly based on these comparisons. Thus, the tank system according to the invention brings the same advantages as described in detail with respect to the method according to the invention. The target temperature gradient can be calculated and / or read from a memory by means of the calculation unit for comparison. The calculation unit can be configured and configured for calculating the target temperature gradient in the manner described in detail above. The tank system can be configured and configured as part of a fuel cell system. The fuel cell system can be configured and configured as part of a vehicle.

[0025] According to the invention, a tank system is also provided which is configured and designed to carry out the method described above. That is, the tank system can have suitable sensors, suitable computing units and / or suitable actuators for carrying out the method.

[0026] Another aspect of the invention relates to a computer program product, which includes instructions that cause the method steps according to the invention to be carried out in a tank system as described above. The invention also relates to a computer-readable, in particular non-volatile, storage medium on which such a computer program product is stored. The computer program product and the storage medium according to the invention therefore also bring about the advantages described above.

[0027] The computer program product can be executed as a computer-readable instruction code in any suitable programming language and / or machine language (such as JAVA, C++, C# and / or Python). The computer program product can be stored on a computer-readable storage medium such as a data disk, a replaceable storage device, a volatile or non-volatile memory or a built-in memory / processor. The instruction code can program a computer or other programmable device such as a controller of a fuel cell system and / or a controller of a vehicle with a fuel cell system so that the required functions are implemented. In addition, the computer program product can be provided in a network, such as the Internet, and can be downloaded by a user when necessary. The computer program product can be implemented not only by software, but also by one or more specialized electronic circuits, that is, in hardware or in any combination, that is, by software components and hardware components. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Measures for improving further advantages of the invention are derived from the following description of various embodiments of the invention, which are schematically shown in the drawings. All features and / or advantages highlighted by the claims, the description or the drawings, including structural details and spatial arrangements, may be important to the invention both individually and in various combinations.

[0029] The accompanying drawings schematically show:

[0030] Figure 1 : A fuel cell system with a tank system according to an embodiment of the present invention;

[0031] Figure 2 : A tank system according to an embodiment of the present invention;

[0032] Figure 3 : A storage medium having a computer program product stored thereon according to an embodiment of the present invention;

[0033] Figure 4 : A flow chart for illustrating a method according to one embodiment of the present invention.

[0034] In the figures, elements having the same function and mode of action are respectively provided with the same reference symbols. DETAILED DESCRIPTION

[0035] Figure 1 A fuel cell system 10 is shown which is configured and constructed for mobile use in a vehicle. The fuel cell system 10 has a filling section 30 which has a tank connection 35 in the form of a connecting pipe. The fuel cell system 10 also has a storage section 31 which has a fuel line assembly 15, a fuel tank assembly 38 and a valve 36 in the form of a shut-off or stop valve. In addition, the fuel cell system 10 has a supply section 32 which has a pressure regulator 37 through which the fuel can be led from the storage section 31 to the fuel cell section 33 of the fuel cell system 10 in a controlled manner. In addition, the fuel cell system 10 also has a power section 34 in which the current or voltage generated in the fuel cell section 10 can be converted into driving power for the vehicle.

[0036] exist Figure 2 As shown in Figure 1 The tank system 11 of the fuel cell system 10 shown in FIG. Figure 2The tank system 11 shown in FIG. 1 has three fuel tanks 12, 13, 14, a fuel line assembly 15 for conducting fuel from the fuel tanks 12, 13, 14, and a valve assembly 16 for conducting fuel from the fuel tanks 12, 13, 14 through the fuel line assembly 15 in a controlled manner. The fuel tanks 12, 13, 14 are connected to the fuel line assembly 15 in parallel with each other. The tank system 11 also has a pressure sensor 39 for determining the line pressure in the fuel line assembly 15. The valve assembly 16 has three outlet valves 17, 18, 19, wherein the outlet valves 17, 18, 19 are respectively mounted on one fuel tank 12, 13, 14. In addition, a temperature sensor 25 is configured in each tank for determining the temperature in each fuel tank 12, 13, 14. The tank system 11 also has a determination unit 21 for determining the temperature gradient with respect to the temperature in each fuel tank 12, 13, 14 during the operation of the fuel cell system 10. The determination unit 21 has a temperature sensor 25 in each fuel tank 12, 13, 14. In addition, the tank system has a calculation unit 22 for comparing the determined temperature gradients with each other and with at least one calculated target temperature gradient, and for detecting a fault in the valve assembly 16 based on these comparisons. In addition, the tank system 11 has a control unit 20 for electrically actuating the outlet valves 17, 18, 19. The control unit 20 is shown schematically and can have a plurality of components that are spaced apart from each other. The control unit 20 can be a controller, in particular in the form of a vehicle controller. According to Figure 2 In the embodiment shown in , the computing unit 22 is a component of the control unit 20 .

[0037] exist Figure 3 2 shows a computer-readable non-volatile storage medium 24 in the form of a memory stick. A computer program product 23 is stored on the storage medium 24. The computer program product 23 includes instructions that cause the Figure 1 and Figure 2 The tank system 11 shown in the drawings performs a method, which is subsequently referred to as Figure 4 Explain.

[0038] Reference Figure 4The flowchart shown in describes a method for detecting a fault of the valve assembly 16 described above. More precisely, the method can be used to find out whether the valve assembly 16 has a fault, especially a fault in the form of at least one outlet valve that cannot be opened. For this purpose, in a first step S1, the outlet valves 17, 18, 19 are first electrically controlled or energized in parallel. In a second step S2, during the operation of the fuel cell system 10, a temperature gradient is determined in each fuel tank 12, 13, 14 with respect to the temperature in each fuel tank 12, 13, 14. In a third step S3, the temperature gradients determined are then compared with each other. In a fourth step S4, a possible fault of the valve assembly 16 is detected based on these comparisons. In other words, it is inferred from the comparison whether there is a fault in the valve assembly 16. In particular, it can be inferred that the outlet valves 17, 18, 19 on the fuel tanks 12, 13, 14 where the lowest temperature gradient or the lowest degree of cooling is measured are not opened as desired, wherein the determined temperature gradient is also different from other temperature gradients in a predetermined manner or to a predetermined high degree. If a fault is detected, in particular in the form of at least one outlet valve 17 , 18 , 19 that cannot be opened, steps S1 to S5 or S1n to S5 are executed again, wherein in step S1n outlet valves 17 , 18 , 19 are energized more strongly than before or than in the previous cycle.

[0039] In addition to the embodiments shown, the present invention also allows other configuration principles. That is, the present invention should not be limited to the embodiments described with reference to the accompanying drawings. Therefore, it can be that the temperature gradients obtained are compared in pairs, alternatively or additionally, and the temperature gradients obtained are compared with at least one provided target temperature gradient. When comparing, the obtained temperature gradients can be compared with each other in pairs, wherein, if the difference between the smaller temperature gradient obtained for example for the first fuel tank 12 and the larger temperature gradient obtained for example for the second fuel tank 13 is greater than a predetermined limit difference, a fault is detected in and / or on the discharge valve 17, 18, 19 for the first fuel tank 12 or a corresponding fault is inferred. The limit difference can be predetermined according to the temperature in each fuel tank 12, 13, 14 and according to the ambient temperature around the fuel tanks 12, 13, 14. During the comparison, the determined temperature gradients can be compared individually with the associated predetermined target temperature gradients, wherein if the determined temperature gradient for a specific fuel tank 12, 13, 14 is less than the associated target temperature gradient, a fault in and / or at the outlet valve 17, 18, 19 for the specific fuel tank (12, 13, 14) can be detected. The target temperature gradient can be predetermined as a function of the gas pressure in the respective fuel tank 12, 13, 14, as a function of the temperature in the respective fuel tank 12, 13, 14 and / or as a function of the ambient temperature around the fuel tank 12, 13, 14.

Claims

1. A method for detecting a fault in a valve assembly (16) in a tank system (11) for a fuel cell system (10), wherein: The tank system (11) comprises a plurality of fuel tanks (12, 13, 14), a fuel line assembly (15) for guiding fuel from the fuel tanks (12, 13, 14), and a valve assembly (16), wherein the valve assembly has a discharge valve (17, 18, 19) for each fuel tank (12, 13, 14) and is used to guide the fuel from the fuel tank (12, 13, 14) through the fuel line assembly (15) in a controlled manner. Features: - determining a temperature gradient with respect to the temperature in each fuel tank (12, 13, 14) during operation of the fuel cell system (10); - comparing the determined temperature gradients with each other and / or comparing the determined temperature gradients with at least one provided target temperature gradient; and - detecting a malfunction of the valve assembly (16) based on the comparison.

2. The method according to claim 1, It is characterized in that During the comparison, the determined temperature gradients are compared with one another in pairs, wherein if the difference between the smaller temperature gradient determined for the first fuel tank (12) and the larger temperature gradient determined for the second fuel tank (13) is greater than a predetermined limit difference, a fault is detected in the outlet valve (17, 18, 19) for the first fuel tank (12) and / or at the outlet valve for the first fuel tank.

3. The method according to claim 2, It is characterized in that The limit difference is predetermined as a function of the temperature in the respective fuel tank (12, 13, 14) and / or as a function of the ambient temperature around the fuel tank (12, 13, 14).

4. The method according to any one of the preceding claims, It is characterized in that During the comparison, the determined temperature gradients are individually compared with the associated predetermined target temperature gradients, wherein if the determined temperature gradient for a specific fuel tank (12, 13, 14) is less than the associated target temperature gradient, a fault is detected in the outlet valve (17, 18, 19) for the specific fuel tank (12, 13, 14) and / or at the outlet valve for the specific fuel tank.

5. The method according to claim 4, It is characterized in that The target temperature gradient is predetermined according to the gas pressure in each fuel tank (12, 13, 14), according to the temperature in each fuel tank (12, 13, 14) and / or according to the ambient temperature around the fuel tank (12, 13, 14).

6. The method according to any one of the preceding claims, It is characterized in that If a fault is detected, the method steps according to claim 1 are repeated and the outlet valve (17, 18, 19) is electrically actuated with a higher current than before the fault was detected.

7. A tank system (11) for a fuel cell system (10), comprising a plurality of fuel tanks (12, 13, 14), a fuel line assembly (15) for guiding fuel from the fuel tanks (12, 13, 14), and a valve assembly (16), wherein the valve assembly has a discharge valve (17, 18, 19) for each fuel tank (12, 13, 14), respectively, for guiding fuel from the fuel tanks (12, 13, 14) through the fuel line assembly (15) in a controlled manner, characterized in that: - a determination unit (21) for determining a temperature gradient with respect to the temperature in each fuel tank (12, 13, 14) during operation of the fuel cell system (10); A calculation unit (22) for comparing the determined temperature gradients with one another and / or for comparing the determined temperature gradients with at least one provided target temperature gradient and for detecting a fault in the valve assembly (16) based on the comparison.

8. The tank system (11) according to claim 7, which is configured and designed to carry out the method according to any one of claims 1 to 6.

9. A computer program product (23) comprising instructions causing the method steps according to any one of claims 1 to 6 to be performed in a tank system (11) according to any one of claims 7 to 8.

10. A computer-readable storage medium (24) on which the computer program product according to claim 9 is stored.

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