Method for regulating fuel concentration in a fuel cell system, fuel cell system, vehicle, computer program product and storage medium
Patent Information
- Application Number
- CN202480084049.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-18
- Filing Date
- 2024-12-06
- Publication Date
- 2026-08-18
Smart Images
Figure CN122603419A_ABST
Abstract
Description
Technical Field
[0001] The technology disclosed herein relates to methods for adjusting fuel concentration in fuel cell systems, and particularly in fuel cell systems of vehicles. The technology also relates to fuel cell systems and vehicles for implementing the methods. Furthermore, the described technology relates to computer program products for implementing the methods, and computer-readable storage media on which such computer program products are stored. Background Technology
[0002] Fuel cell systems for mobile applications are known in the prior art. In vehicles, fuel cell systems are generally configured to power the drive motor and / or buffer batteries used to propel the vehicle. This type of fuel cell system has a fuel cell stack. A fuel cell stack typically has multiple fuel cells, each with two electrodes and a membrane assembly between the two electrodes. In the fuel cell stack, fuel (especially hydrogen) can react with oxygen in the form of reverse electrolysis, thereby generating an electric current. Fuel can be supplied to the fuel cell stack from one or more pressure vessels in the vehicle. Oxygen is typically extracted from ambient air.
[0003] Known fuel cell systems have a water separator in the anode subsystem to remove liquid water from the process gas flowing from the anode into the water separator. The separated water can be discharged from the water separator via a purge path. The process gas can be guided back into the fuel cell and / or fuel cell stack via a recirculation path. Here, a distinction should be made between purging (so-called draining) and purging (so-called purging). Purging specifically refers to the removal of unwanted gases, contaminants, and / or liquids from the water separator and / or system components upstream of the water separator. For example, purging can be performed to remove air or other contaminants from the process gas to be recirculated into the fuel cell. This is important to achieve the most efficient and undisturbed fuel cell reaction possible. Purging specifically refers to the complete or partial removal of liquids, particularly water, from the water separator. Purging can be performed for maintenance work, servicing, and / or to safely shut down the fuel cell system and / or prepare for a safe restart under icing conditions.
[0004] In addition, purging and / or venting can be performed to adjust the fuel concentration in the fuel cell system (and especially in the recirculation path). Purging and / or venting for adjusting the desired fuel concentration can be performed using methods and systems that utilize empirical control, virtual models, and / or various sensors. Summary of the Invention
[0005] The purpose of this invention is to provide an improved method and system for adjusting the fuel concentration in a fuel cell system.
[0006] The aforementioned objectives are achieved through the various patent claims. In particular, they are achieved through the method according to claim 1 and the fuel cell system, vehicle, computer program product, and computer-readable storage medium according to the co-claims. Further advantages of the disclosed technology are given in the dependent claims, specification, and drawings. Here, the features described in conjunction with the method also apply to the fuel cell system, vehicle, computer program product, and storage medium, and vice versa, so that the disclosures with respect to each aspect are always mutually referenced and / or always mutually referential.
[0007] According to a first aspect of the present invention, a method for adjusting the fuel concentration in a fuel cell system is provided. The fuel cell system includes a fuel cell, a water separator, a fuel inlet path for directing fuel to the fuel cell, a process gas outlet path for directing process gas out of the fuel cell and into the water separator, a purge path for directing water and process gas from the water separator to the surrounding environment of the fuel cell system, and an outlet valve for controlling the molar flow rate through the purge path. The method includes the following steps:
[0008] - Determine the actual molar flow rate through the purge path.
[0009] - Determine the reference molar flow rate,
[0010] - Compare the actual molar flow rate with the reference molar flow rate.
[0011] - Adjust the opening characteristics of the outlet valve based on the comparison.
[0012] Within the scope of this development, it has been recognized that convincing conclusions about the fuel concentration in the process gas can be readily drawn using the actual molar flow rate in the purge path and / or through the outlet valve. If the process gas directed into the water separator has high humidity, high water vapor content, and / or high nitrogen content, it will escape from the water separator more slowly compared to low humidity, low water vapor content, and / or low nitrogen content. For example, nitrogen and water vapor escape more slowly through the outlet valve due to their higher molecular weight compared to hydrogen. In other words, if the process gas directed into the water separator has a high fuel concentration (e.g., high hydrogen concentration), it can escape from the water separator more quickly through the purge path compared to a lower fuel concentration. The actual molar flow rate can be determined using sensor devices, mathematical methods, and / or virtual models. For example, the actual molar flow rate can be determined using pressure sensor devices used to determine anode pressure. Furthermore, at least one virtual model can be used to determine or calculate the actual molar flow rate based on measurements. The target molar flow rate can be calculated (e.g., in real time) or read from a computer-readable storage medium. In addition, the target molar flow rate can be determined based on the operating parameters and / or operating status of the fuel cell system.
[0013] Here, "determine" can be understood as the calculation and / or measurement of values and / or data. That is, in order to determine, for example, the actual molar flow rate and / or the corresponding actual molar flow rate value, the value can be measured first, and the value can then be further developed into a final value by means of calculation methods and / or at least one virtual model. Furthermore, "determine" can be understood as reading data from a computer-readable storage medium.
[0014] The method can be implemented using a water separator connected to a purge path, in which there is only one outlet valve, through which purging and venting can be controlled. Within the scope of this technology, "control" can be understood as open-loop control and / or closed-loop control. Here, the purge path can be understood as a purging and / or venting path. The water separator can be a classic water separator and / or a section in a fuel cell system through which process water and process gases (particularly in the form of purge gases) can be discharged from the fuel cell system. Therefore, the water separator described herein can be understood as a section and / or unit by which process water and / or purge gases can be prevented from being discharged from the fuel cell system together with the purge gases.
[0015] The opening characteristics can be adjusted such that all or as much water as possible is first diverted out of the water separator, followed by a predetermined amount of process gas. By diverting the predetermined amount of process gas out of the water separator, the desired fuel concentration can be adjusted. Within the scope of this method, a mass balance can be established for this purpose. The process gas flowing into the water separator can be described sufficiently well via a virtual model. The mass balance can be based on the conclusion that the process gas flowing out of the water separator through the outlet valve causes a pressure loss, or is replaced by the process gas flowing into the water separator. During the purging process, i.e., during drainage, no process gas is diverted out of the water separator. At high nitrogen and / or water vapor concentrations in the process gas, the process gas flows relatively slowly, thus allowing less process gas to flow through the outlet valve or out of the water separator. These relationships can ultimately be utilized when adjusting the opening characteristics of the outlet valve to adjust the desired fuel concentration in the recirculated process gas. The actual molar flow rate can be understood as the actual molar flow rate during venting. A reference molar flow rate can be understood as at least one reference value, and the actual molar flow rate value is correlated with the at least one reference value within the scope of comparison.
[0016] The adjustment of the opening characteristics of the outlet valve based on comparison can be understood as setting the outlet valve to a closed or open state and / or adjusting the duty cycle of the outlet valve according to the difference between the actual molar flow rate and the reference molar flow rate. Here, "adjustment" can be understood as changing and / or maintaining the current state and / or characteristics.
[0017] The outlet valve can be designed as a shut-off valve. Therefore, the opening characteristics of the outlet valve can be adjusted and / or controlled only between a fully open state and a fully closed state. Here, a valve can be understood as a device for open-loop and / or closed-loop control of liquid, gas, and / or solid particle flows through pipes, channels, or hollow spaces (e.g., purge paths).
[0018] Process gas can be understood as the anode gas used for processing and / or chemical reactions in a fuel cell. The anode gas supplied to the fuel cell may contain fuel (e.g., hydrogen) and / or recycled process gas, which may include the components described above. Molar flow rate can be understood as the amount of fluid, particularly process gas, flowing out of the water separator per unit time via the purge path.
[0019] According to another embodiment of this technology, if the actual molar flow rate is determined to be greater than the reference molar flow rate based on the comparison, the duty cycle of the outlet valve can be reduced. Alternatively or additionally, if the actual molar flow rate is determined to be less than the reference molar flow rate based on the comparison, the duty cycle of the outlet valve can be increased. This allows for particularly simple adjustment of the desired molar concentration. The duty cycle can be understood as a ratio or percentage, which describes the proportion of time a periodic function is active or on. The duty cycle can indicate the percentage of time the valve is regulated to a particular state (especially whether it is in the open or closed state).
[0020] Furthermore, it can be determined whether the outlet valve is open or closed, with the comparison performed only when the outlet valve is open. Therefore, the current state regarding the molar flow rate can be considered only when the outlet valve is actuated. This allows the method to be performed particularly efficiently. The comparison or corresponding calculation can also be performed during the time the outlet valve is closed. However, for the adjustment of the opening characteristics, it is preferable to use only the measurement data and / or state determined during the opening of the outlet valve.
[0021] In the method described herein, the anode pressure of the fuel cell can also be determined, and a reference molar flow rate can be determined based on the anode pressure. Therefore, the reference molar flow rate can be defined proportionally to the anode pressure. This allows for particularly reliable adjustment of the desired fuel concentration to the desired value. Anode pressure can be understood as the gas pressure in and / or at the anode of the fuel cell system, the gas pressure in the fuel inlet path upstream of the anode, and / or the gas pressure in the process gas outlet path downstream of the anode. That is, the anode pressure can be determined directly at the anode, upstream of the anode, and / or downstream of the anode. Anode pressure can be determined using sensor devices in and / or at the anode and / or using a virtual model.
[0022] Furthermore, it is feasible to determine the fuel consumption of the fuel cell in the method according to the technology described herein, and adjust the on-start characteristics based on said fuel consumption. This also allows for particularly simple and reliable adjustment of the desired fuel concentration. Fuel consumption of the fuel cell can be understood as the amount of fuel consumed and / or chemically converted by the fuel cell and supplied to the fuel cell over a certain period of time. Fuel consumption can be determined and / or measured in kilograms or liters per hour, depending on the fuel type. To determine fuel consumption, the current generated by the fuel cell can be determined. Fuel consumption can then be determined based on the generated current. To determine the current, a current sensor can be positioned at and / or within the fuel cell.
[0023] Furthermore, in this technology, the gas pressure characteristics of the fuel cell can be determined, and the opening characteristics can be adjusted based on these gas pressure characteristics. Gas pressure characteristics have proven to be a relatively simple and reliable parameter to consider for adjusting the desired fuel concentration. For example, if the fuel supply to the fuel cell is suddenly increased without changing fuel consumption, the pressure in the water separator can suddenly increase. According to this method, such pressure jumps can be taken into account as disturbances or calculated accordingly, so that even in these cases, the opening characteristics can be adjusted in the desired manner as much as possible. Gas pressure characteristics can be determined or measured using pressure sensors on and / or in the fuel inlet path.
[0024] Another aspect of this technology relates to a fuel cell system for a vehicle, wherein the fuel cell system has a controller for performing the methods described above. Therefore, this fuel cell system provides the same advantages described in association with the methods. The fuel cell system is preferably configured for mobility applications, such as vehicles, particularly for providing energy to at least one drive unit (such as an electric motor for the movement of the vehicle). The fuel cell system may have at least one fuel cell, which can also be understood as a fuel cell stack having multiple fuel cells. The controller may have suitable determination and / or calculation units, for example, as part of at least one computer and / or at least one control device. The controller may also have comparison units and / or correction units for performing comparisons, evaluations, and / or corrections. A water separator may be located directly downstream of the anode in the process gas outlet path. The water separator may be configured as part of the anode subsystem. An outlet valve may be constructed directly downstream of the water separator, at the water separator, or as an integral part of the water separator. The outlet valve may be configured as a combined outlet valve for purging and venting. The fuel cell system may be configured as a PEM fuel cell system. The fuel cell system may have a current sensor for determining the current generated by the fuel cell and a pressure sensor for determining the anode pressure. The fuel cell system may also have an injector / syringe and a current sensor for determining the current consumed by the injector / syringe.
[0025] Furthermore, one aspect of the proposed technology relates to a vehicle equipped with a fuel cell system as described above and at least one electric motor for driving the vehicle, wherein the fuel cell system is configured to supply power to the at least one electric motor. Therefore, the vehicle also possesses the advantages described above. The vehicle can be understood as a motor vehicle, such as a two-wheeled vehicle driven by an electric motor, a car, and a truck. The vehicle can also be understood as a land vehicle, an air vehicle, a water vehicle, a rail vehicle, a spacecraft, and a robot. The vehicle can also be understood as a pure electric vehicle and a hybrid electric vehicle, supplemented by the at least one electric motor, which also has an internal combustion engine for driving the vehicle. The vehicle can be understood as a so-called FCEV (Fuel Cell Electric Vehicle).
[0026] Furthermore, the technology disclosed herein includes a computer program product and a computer-readable, particularly non-volatile, storage medium on which the computer program product is stored. Therefore, the computer program product and the computer-readable storage medium also offer the aforementioned advantages. The computer program product may include instructions that, when executed by a computer (e.g., a controller), cause the computer to perform the proposed method in the vehicle as described above. The computer-readable storage medium can also be understood as a controller and / or control device (e.g., a vehicle control device) together with the computer program product installed therein.
[0027] Computer program products can be implemented as computer-readable instruction code in any suitable programming language and / or machine language (e.g., JAVA, C++, C#, and / or Python). Computer program products can be stored on computer-readable storage media, such as data disks, removable disks, volatile or non-volatile memory, or internal memory / processor. The instruction code can program computers and other programmable devices (e.g., control devices) to perform the desired functions. Furthermore, computer program products can be provided on a network (e.g., the Internet) and / or downloaded by a user from the network when needed. Computer program products can be implemented not only by means of software but also by means of one or more dedicated electronic circuits, that is, in hardware, or in any hybrid form, that is, by means of software components and hardware components. Attached Figure Description
[0028] Further measures are derived from the following description of various embodiments, which are schematically illustrated in the accompanying drawings. All features and / or advantages derived from the claims, specification, or drawings, including structural details and spatial arrangements, may be important not only individually but also in various combinations.
[0029] The diagram illustrates the following:
[0030] Figure 1 A fuel cell system according to one embodiment of the present technology is shown;
[0031] Figure 2 The water separator of the fuel cell system is shown in its first operating state.
[0032] Figure 3 The water separator of the fuel cell system is shown in its second operating state.
[0033] Figure 4 A computer-readable storage medium according to one embodiment of the present technology, together with a computer program product stored thereon, is shown.
[0034] Figure 5 A vehicle equipped with a fuel cell system according to one embodiment of the present technology is shown;
[0035] Figure 6 The diagram illustrates a method according to one embodiment of the present technology; and
[0036] Figure 7 A diagram is shown to further illustrate the method. Detailed Implementation
[0037] In the accompanying drawings, elements with the same function and mode of operation are represented by the same reference numerals.
[0038] Figure 1 A fuel cell system 10 according to a feasible embodiment is shown. The fuel cell system 10 shown has a fuel cell 11 with an anode 21 and a cathode 22. More specifically, the fuel cell 11 is designed as a fuel cell stack and has an anode region and a cathode region. The fuel cell system 10 has a water separator 12, a fuel inlet path 13 (for directing fuel to the fuel cell 11), and a process gas outlet path 14 (for directing process gas 16 from the fuel cell 11 and into the water separator 12). In addition, the fuel cell system 10 has a recirculation path 15 (for directing process gas 16 from the water separator 12 back to the fuel inlet path 13) and a purge path 17 (for directing water and process gas 16 from the water separator 12 into the environment of the fuel cell system 10). In the purge path 17, the fuel cell system 10 has an outlet valve 18 for controlling the molar flow rate through the purge path 17. In addition, the fuel cell system 10 has an injector / injector 23 that delivers fuel or anode gas to the fuel cell 11 and delivers process gas 16 to the fuel inlet path 13 via the process gas outlet path 14 and the recirculation path 15.
[0039] The fuel cell system 10 shown also includes sensors, including a pressure sensor 19 and two current sensors 26 and 27. The pressure sensor 19 is positioned to determine the gas pressure in the fuel inlet path downstream of the injector / syringe 23 and upstream of the anode 21. The first current sensor 26 is positioned to determine the current generated by the fuel cell 11, or a corresponding current value. The second current sensor 27 is positioned to determine the current consumed by the injector / syringe 23, or a corresponding current value. Sensors 19, 26, and 27 can, in principle, be positioned at other locations. Furthermore, the fuel cell system 10 has a controller 20 for operating the fuel cell system 10. The controller 20 is signal-connected to the sensors. The signal connection shown can be wired or wireless.
[0040] Figure 2 The water separator 12 is shown in more detail. Figure 2 The water separator 12 shown is empty of water, and the outlet valve 18 is open. In this operating state, process gas 16, which flows in through process gas outlet path 14, can flow out of the water separator 12 via recirculation path 15 and purging path 17. Figure 3 A water separator 12 is shown, in which the outlet valve 18 is closed and water accumulates in the water separator 12. In this case, the process gas 16 can only flow through the recirculation path 15, and in particular cannot flow out of the water separator 12 through the purging path 17.
[0041] Figure 4 A computer-readable and non-volatile storage medium 60 is shown, on which a computer program product 50 is stored. The storage medium 60 is designed in the form of a flash drive. The computer program product 50 includes instructions that, when executed by a computer, cause the computer to implement a method for adjusting the fuel concentration in the fuel cell system 10 in the illustrated vehicle 100. Reference will be made below. Figure 6 and Figure 7 Describe a feasible method.
[0042] Figure 5 A vehicle 100 in the form of a car is shown. The vehicle 100 has a fuel cell system 10 as described above, which includes a fuel cell 11 and two electric motors 40 for driving the vehicle 100. The vehicle 100 also has a pressure vessel 70 containing fuel for supplying fuel to the fuel cell system 10. The fuel cell system 10 is configured to power the electric motors 40 and / or a buffer battery (not shown). Furthermore, the vehicle 100 has a controller 20 in the form of a vehicle control device. The controller 20 and the pressure vessel 70 can be considered as part of the fuel cell system 10.
[0043] Figure 6 A flowchart is shown to illustrate a method for adjusting the fuel concentration in the illustrated fuel cell system 10. In the first step S1, the current consumed by the injector / syringe 23 is measured using a current sensor 27. In the second step S2, the current generated by the fuel cell 11 or the fuel cell stack is measured using a current sensor 26. In the third step S3, the anode pressure is determined or measured using a pressure sensor. In the fourth step S4, a virtual model of the injector / syringe 23 is created based on the measured current, and the fuel flow to the fuel cell 11 is calculated using this virtual model. In the fifth step S5, the fuel consumption of the fuel cell 11 is calculated based on the measured current. In the sixth step S6, the actual molar flow rate to the water separator 12 and the actual molar flow rate through the purge path 17 are calculated based on the fuel flow rate to the fuel cell 11 and the fuel consumption in the fuel cell 11. In the seventh step S7, the corresponding fuel consumption is calculated based on the changing anode pressure. In the eighth step S8, a reference molar flow rate is determined based on the fuel consumption. That is, the reference molar flow rate is defined proportionally to the anode pressure. In step S9, a comparison is performed between the actual molar flow rate and the reference molar flow rate. If the comparison shows that the actual molar flow rate is greater than the reference molar flow rate by a predefined or definable value, the duty cycle of the outlet valve 18 is decreased in step S10. If the comparison shows that the actual molar flow rate is less than the reference molar flow rate, the duty cycle of the outlet valve 18 is increased. Adjusting the duty cycle causes the corresponding opening characteristics of the outlet valve 18. The comparison according to step S9 is performed only in the example shown if the outlet valve 18 is detected to be open.
[0044] Figure 7 A graph is shown, illustrating the measured and calculated values according to the described method. Figure 7 The determined actual molar flow rate is shown in Molar Flow Rate Diagram 31. The opening characteristics or duty cycle of outlet valve 18 are shown in Duty Cycle Diagram 32. Duty Cycle Diagram 32 corresponds to the control signals used to open and close outlet valve 18. Figure 7 The corresponding purging or opening times t1, t2, t3, and t4 for outlet valve 18 are shown. During these times, outlet valve 18 is open. Furthermore, in... Figure 7The diagram shows a lower reference value 33, a middle reference value 34, and an upper reference value 35. The reference molar flow rate described above can be determined based on reference values 33, 34, and 35, and particularly on the middle and upper reference values 34 and 35. More specifically, in the example shown, an attempt is made to keep the determined actual molar flow rate as close as possible to the middle reference value 34 and below the upper reference value 35 by comparing the actual molar flow rate with the reference values 33, 34, and 35. With regard to the first opening time t1, the actual molar flow rate is relatively low. At this point in time, venting may not have occurred. During the second opening time t2 and the fourth opening time t4, the actual molar flow rate is relatively high and exceeds the upper reference value, from which venting can be inferred. During the third opening time t3, although the actual molar flow rate is low, it is partially higher than the upper reference value 35 sufficiently, so venting can also be inferred there. The comparison at opening time t1 can cause an increase in the duty cycle of outlet valve 18. The comparison at opening times t2 and t4 can cause a decrease in the duty cycle of outlet valve 18. The comparison at opening time t3 can cause the duty cycle of outlet valve 18 to remain unchanged.
[0045] In addition to the embodiments shown, the technology disclosed herein also allows for other design principles. That is, the technology should not be considered as limited to the embodiments illustrated with reference to the accompanying drawings.
[0046] List of reference numerals
[0047] 10. Fuel Cell System
[0048] 11. Fuel Cells
[0049] 12 Water Separator
[0050] 13 Fuel Inlet Path
[0051] 14 Process Gas Outlet Path
[0052] 15 Recycle Path
[0053] 16 Process Gases
[0054] 17. Purging Path
[0055] 18. Outlet valve
[0056] 19 Pressure Sensor
[0057] 20 Controllers
[0058] 21 Anode
[0059] 22 Cathode
[0060] 23. Injector / Ejector
[0061] 24 Pressure Sensors
[0062] 25 Pressure Sensor
[0063] 26-Molar Flow Chart
[0064] 27 Duty Cycle Chart
[0065] 28 reference values
[0066] 29 reference values
[0067] 30 (Reference value)
[0068] 40 electric motors
[0069] 50 Computer Program Products
[0070] 60 Storage media
[0071] 70 Pressure Vessel
[0072] 100 means of transportation
Claims
1. A method for adjusting the fuel concentration in a fuel cell system (10), wherein, The fuel cell system (10) includes a fuel cell (11), a water separator (12), a fuel inlet path (13) for directing fuel to the fuel cell (11), a process gas outlet path (14) for directing process gas (16) out of the fuel cell (11) and into the water separator (12), a purge path (17) for directing water and process gas (16) from the water separator (12) to the surrounding environment of the fuel cell system (10), and an outlet valve (18) for controlling the molar flow rate through the purge path (17), wherein the method includes: - Determine the actual molar flow rate through the purge path (17), - Determine the reference molar flow rate, - Compare the actual molar flow rate with the reference molar flow rate. - Adjust the opening characteristics of the outlet valve (18) based on the comparison.
2. The method according to claim 1, wherein, If it has been determined based on the comparison that the actual molar flow rate is greater than the reference molar flow rate, then reduce the duty cycle of the outlet valve (18); And / or if it has been determined based on the comparison that the actual molar flow rate is less than the reference molar flow rate, then increase the duty cycle of the outlet valve (18).
3. The method according to any one of the preceding claims, wherein, Determine whether the outlet valve (18) is open or closed, and perform the comparison only when the outlet valve (18) is open.
4. The method according to any one of the preceding claims, wherein, The anode pressure of the fuel cell (11) is determined, and a reference molar flow rate is determined based on the anode pressure.
5. The method according to any one of the preceding claims, wherein, The fuel consumption of the fuel cell (11) is determined, and the start-up characteristics are adjusted according to the fuel consumption.
6. The method according to any one of the preceding claims, wherein, The gas pressure characteristics of the fuel cell (11) are determined, and the opening characteristics are adjusted according to the gas pressure characteristics.
7. A fuel cell system (10), wherein the fuel cell system has a controller (20), The controller (20) is configured to perform the method according to any one of the preceding claims.
8. A vehicle (100) having a fuel cell system (10) according to claim 7 and at least one electric motor (40) for driving the vehicle (100), wherein, The fuel cell system (10) is configured to supply power to the at least one electric motor (40).
9. A computer program product (50) comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 6 in a vehicle (100) according to claim 8.
10. A computer-readable storage medium (60) having a computer program product (50) according to claim 9 stored thereon.