DE102024107318A1 - Method and device for adjusting a valve in a fuel cell system, vehicle, computer program product and storage medium - Google Patents

Abstract

The technology disclosed here relates to a method for adjusting a valve (11), comprising: varying an electrical control current with which the valve (11) is controlled, decomposing the varying control current into an averaged current component and a varying current component, determining an averaged valve position based on the averaged current component, and adjusting the valve (11) based on the averaged valve position. The technology further relates to a device (10) and a computer program product (30) for carrying out the method, as well as to a computer-readable storage medium (40) on which the computer program product (30) is stored.

Description

The technology disclosed here relates to a method and a device for adjusting a valve in a fuel cell system. The technology further relates to a vehicle having such a device, a computer program product for executing the method, and a computer-readable storage medium on which such a computer program product is stored.

Various systems and methods are known in the prior art for determining or at least estimating the amount of fuel introduced into a fuel cell of a fuel cell system. Based on the determined fuel quantity, preferred operating conditions can be determined and/or adjusted. In known systems, these operating conditions are approximately calculated using measured variables such as the anode pressure. Various, sometimes complex and/or error-prone, measurement methods are known for performing such measurements. The primary goal here is to ensure that there is always sufficient fuel in the anode. Too little fuel in the anode can lead to damage to the fuel cell. Unnecessarily high hydrogen quantities in the anode should, of course, also be avoided. To control the fuel quantity in the anode and/or upstream of the anode, at least one injector/ejector with a proportional valve is used in known fuel cell systems. In known systems, the proportional valve is controlled via a model-free or model-based control system. A pressure difference is formed between the target pressure and the actual pressure. The pressure difference is translated into a voltage or current signal, which is used to control a solenoid. The solenoid is controlled by a magnetic force that correlates with the current signal, is held in balance against a spring of the proportional valve, and changes the valve opening of the proportional valve. The current signal or the corresponding current can be varied using various methods and systems to reduce the pressure difference. However, when combined with a dead time in the system, control becomes difficult. With a known valve opening, the mass flow through the proportional valve can be determined from the valve position of the proportional valve. However, due to the hysteresis of the magnetically controlled proportional valve, a clear relationship between current and valve opening is not possible in known systems. For a given current, the resulting valve opening can vary relatively significantly. Therefore, in conventional systems and methods, the proportional valve is controlled using feedback from pressure sensors in the fuel cell system. Due to the dead time and hysteresis, the control in conventional systems with PI or PID controllers is not ideal and can lead to increased steady-state errors and steady-state oscillating behavior.

The object of the present invention is to provide improved methods and devices for adjusting a valve, in particular a valve in a fuel cell system.

The above object is achieved by the patent claims. In particular, the above object is achieved by the method according to claim 1 and by the device, the vehicle, the computer program product, and the computer-readable storage medium according to the independent claims. Further advantages of the disclosed technology emerge from the dependent claims, the description, and the figures. Features described in connection with the method also apply in connection with the device, the vehicle, the computer program product, the storage medium, and vice versa, so that with regard to the disclosure, reciprocal reference is and/or can always be made to the individual aspects.

• - Variieren eines elektrischen Ansteuerstroms, mit welchem das Ventil angesteuert wird,
• - Zerlegen des variierenden Ansteuerstroms in einen gemittelten Stromteil und in einen variierenden Stromteil,
• - Ermitteln einer gemittelten Ventilposition basierend auf dem gemittelten Stromteil und
• - Einstellen des Ventils basierend auf der (ermittelten) gemittelten Ventilposition.

According to a first aspect of the present technology, a method for adjusting a magnetically controlled valve is proposed. The method comprises the following steps:

• - Varying an electrical control current with which the valve is controlled,
• - Decomposing the varying drive current into an average current part and a varying current part,
• - Determining an average valve position based on the averaged current part and
• - Adjusting the valve based on the (determined) average valve position.

Within the scope of the present development, it was recognized that the hysteresis of the valve can be circumvented by a targeted and/or predefined variation of the control current by a defined current value. In particular, a specific averaged valve position can be assigned to a specific current value. This means that each averaged current component can be uniquely assigned a valve position and/or a corresponding mass flow. The averaged valve position can therefore be understood as an averaged valve opening and/or an averaged mass flow resulting from the averaged valve position. Based on the determined valve position, a mass-controlled adjustment of the valve, for example a mass-controlled Pre-control of the valve can also be performed. A known, model-free, pressure-based control of the valve can also be improved. Varying the control current, when the valve is used in and/or on a generic injector/ejector of a fuel cell system, for example, leads to a correspondingly varying pressure profile in the anode pressure. In this case, the valve can be controlled based on the averaged current component and based on a resulting difference between a target anode pressure and an actual anode pressure. This means that the resulting pressure differences can be used to control and/or adjust the valve.

For model-based controllers and/or closed-loop control, the proposed method simplifies the nonlinear hysteresis to a linear or quasi-linear relationship. This means that a linear or quasi-linear relationship between mass flow and valve opening can be assumed for valve adjustment. With sufficiently precise valve control, a pressure sensor for anode gas control is no longer necessary.

Adjusting the valve can be understood as controlling the valve. Controlling the valve can be understood as controlling and/or regulating the valve. Adjusting the valve can therefore be understood as changing and/or deliberately maintaining a valve position. Changing a valve position can be understood as changing the relative position of a control means of the valve, for example the relative position of a valve tappet and/or a valve disk, or deliberately leaving it unchanged. By changing the relative position of the control means, the valve opening or a valve opening cross-section can be increased or decreased. The valve can be set to a fully open state, a fully closed state and/or opening states in between.

The valve can be understood as a proportional valve, for example, a magnetically operated proportional valve. The valve can be understood as a component of an injector/ejector. The method can therefore be implemented as a method for adjusting a valve of an injector/ejector. The valve can have a valve housing, a valve volume, a valve opening, and an adjustable control means for opening and closing the valve opening. Adjusting the valve can be understood as adjusting the control means in order to change the opening cross-section of the valve opening or to deliberately leave it unchanged.

Determining the average valve position can be understood as calculating the average valve position. The average valve position can be understood as an average value corresponding to a valve position. The average valve position can therefore be understood as a valve position that corresponds to an average value that is or was calculated based on several determined valve position values. Analogously, the average current component can be understood as an average value that corresponds to a current component and/or current value.

Varying can be understood as multiple changes over time. Varying the electrical control current can be understood as changing the control current during an operating time with a predefined frequency. The control current is decomposed into two current parts, the averaged current part and the varying current part. The averaged current part can be understood as an averaged stationary current part, which can change over time depending on the control and/or setting of the valve. The decomposition can be carried out using Reynolds decomposition. The averaged and/or stationary current can be the controlling current. I The varying current component can be denoted as I'(t). Accordingly, the following applies: Control current I = I + I'(t). The varying or time-varying current component allows the valve's hysteresis to be traversed in a dynamic and unambiguous manner. The circuit only 'fits' into the hysteresis at a defined point. To achieve a linear or quasi-linear dependency, the amplitude can preferably be adjusted so that the varying current component is larger than the width of the hysteresis. The varying current component can be understood as a variable and/or variable current component.

Determining the average valve position based on the average current component can be understood as meaning that the average valve position can be determined and/or calculated using the average current component as well as possible additional values, parameters, and/or factors. The electrical control current can be understood as the current that can be used to control and thus adjust the valve.

According to an advantageous embodiment of the present technology, it is possible for the electrical drive current to be varied periodically. This means that the drive current is changed continuously and/or uniformly over a variation time. A uniform change can be understood as a change with a uniformly linear or non-linearly decreasing change value. In this way, the averaged valve position can be assigned particularly easily and reliably to the determined averaged current component. The variation time can be understood as the time during which the valve is operated and/or during which the system in which the valve is located is operated.

The amplitude of the varying current component can be continuously reduced during a variation time in which the drive current is varied. This means that the varying current component can initially be set to a high amplitude, for example, which decays or is reduced over time. In this way, potential disadvantages associated with a permanently oscillating drive can be avoided. Reducing the amplitude during the variation time can mean reducing the amplitude evenly or unevenly, over the entire variation time or only over part of the variation time.

Furthermore, it is possible for the control current to be varied with a value in a range between 1 mA and 100 mA in the method proposed here. This means that with each variation and/or change in the control current value, it can be changed by a value that lies in a range between 1 mA and 100 mA, between 10 mA and 50 mA, for example, at approximately 30 mA. For example, the control current can be continuously reduced by 30 mA until the control current reaches a predefined lower limit. It has been shown that the desired valve position can be determined with sufficient accuracy based on such a change without any functional disadvantages arising during valve operation. Varying the control current with a value of, for example, 10 mA can be understood to mean that the control current is changed several times over time by 10 mA each time. However, the change or variation does not always have to be carried out with the same change value. For example, the drive current can be changed by 50 mA in a first change, by 40 mA in a second change, by 30 mA in a third change, etc.

Furthermore, the method described here allows the control current to be varied at a frequency in a range between 0.1 Hz and 10 Hz. With such a change frequency, the valve position can be determined with sufficient accuracy. The variation can be performed at a frequency in a range between 0.2 Hz and 5 Hz or in a range between 0.5 Hz and 2 Hz. Varying the control current at, for example, 2 Hz can be understood as changing the control current twice per second.

• - Variieren eines elektrischen Ansteuerstroms, mit welchem das Ventil angesteuert wird,
• - Zerlegen des variierenden Ansteuerstroms in einen gemittelten Stromteil und in einen variierenden Stromteil,
• - Ermitteln einer gemittelten Ventilposition basierend auf dem gemittelten Stromteil und
• - Einstellen des Ventils basierend auf der (ermittelten) gemittelten Ventilposition.

According to a further aspect of the present invention, a device with a valve is proposed, the device being configured to perform the following steps:

• - Varying an electrical control current with which the valve is controlled,
• - Decomposing the varying drive current into an average current part and a varying current part,
• - Determining an average valve position based on the averaged current part and
• - Adjusting the valve based on the (determined) average valve position.

The device can further be configured to adjust the valve according to the methods described above. Thus, the device provides the same advantages as those described in detail with reference to the method.

The device can be configured as a fuel cell system or as part of a fuel cell system. The fuel cell system can be configured as a PEM fuel cell system. The fuel cell system can comprise a fuel cell with an anode and a cathode, an anode gas supply path, and at least one injector/ejector. The injector/ejector can be configured to supply anode gas to the anode through the anode gas supply path, wherein the valve can be configured as part of the injector/ejector and/or on the injector/ejector. The valve can be configured as a proportional valve. The device and/or the fuel cell system can comprise a fuel supply system, in particular a hydrogen supply system, and an air supply system, wherein the valve can be configured as a component of the fuel supply system.

The device and/or the fuel cell system are preferably configured for mobile applications such as vehicles, in particular for providing electrical energy for at least one drive motor of the vehicle. The fuel cell can be understood as at least one fuel cell and/or a fuel cell stack with several fuel cells. In its simplest form, the fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, thereby generating electricity and heat. The anode and the cathode can be connected by an ion selective or ion-permeable separator. To carry out the method, the device can comprise a controller, an ECU, and/or a correspondingly suitable detection and/or computing unit, for example as part of at least one computer and/or at least one vehicle control unit.

A further aspect of the proposed technology relates to a vehicle with a device as described above, which is configured to generate electrical energy in the vehicle. The vehicle can have at least one drive machine, for example an electric motor, for driving the vehicle. The device can be configured to supply power to the at least one electric motor. The vehicle thus also offers the advantages mentioned above. The term "vehicle" can be understood to mean a motor vehicle such as a motor-driven two-wheeler, a passenger car, and a truck. The term "vehicle" can also be understood to mean a road vehicle, an aircraft, a watercraft, a rail vehicle, a spacecraft, and a robot. The term "vehicle" can also be understood to mean a purely electric vehicle and a hybrid electric vehicle, which, in addition to the at least one electric motor, has an internal combustion engine for driving the vehicle. The term "vehicle" can be understood to mean a so-called FCEV (Fuel Cell Electric Vehicle).

Furthermore, the technology disclosed here comprises a computer program product and a computer-readable, in particular non-volatile, storage medium on which the computer program product is stored. Thus, the computer program product and the computer-readable storage medium also provide the advantages described above. The computer program product can include instructions that, when the computer program product is executed by a computer, for example, a vehicle control unit, cause the computer to execute the method described here in a vehicle as described above. The computer-readable storage medium can be understood as a control unit, for example, a vehicle control unit, with the computer program product installed therein.

The computer program product can be implemented as 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 removable drive, a volatile or non-volatile memory, or a built-in memory/processor. The instruction code can program a computer and other programmable devices, such as a control unit, to perform the desired functions. Furthermore, the computer program product can be provided on a network, such as the Internet, from which it can be downloaded by a user as needed. The computer program product can be implemented using software, one or more special electronic circuits, i.e., in hardware, or in any hybrid form, i.e., using software components and hardware components.

Further measures will become apparent from the following description of various exemplary embodiments, which are schematically illustrated in the figures. All features and/or advantages arising from the claims, the description, or the figures, including structural details and spatial arrangements, may be significant both individually and in various combinations.

• 1 einen Injektor/Ejektor mit einem Ventil gemäß einer Ausführungsform der vorliegenden Technologie,
• 2 eine Vorrichtung gemäß einer Ausführungsform der vorliegenden Technologie,
• 3 ein Diagramm zum Erläutern eines Verfahrens gemäß einer Ausführungsform der vorliegenden Technologie,
• 4 ein Flussdiagramm zum Erläutern eines Verfahrens gemäß einer Ausführungsform der vorliegenden Technologie.
• 5 ein computerlesbares Speichermedium mit einem darauf gespeicherten Computerprogrammprodukt gemäß einer Ausführungsform der vorliegenden Technologie und
• 6 ein Fahrzeug mit einer Vorrichtung gemäß einer Ausführungsform der vorliegenden Technologie.

They show schematically:

• 1 an injector/ejector with a valve according to an embodiment of the present technology,
• 2 a device according to an embodiment of the present technology,
• 3 a diagram for explaining a method according to an embodiment of the present technology,
• 4 a flowchart for explaining a method according to an embodiment of the present technology.
• 5 a computer-readable storage medium having a computer program product stored thereon according to an embodiment of the present technology and
• 6 a vehicle having a device according to an embodiment of the present technology.

Elements with the same function and mode of operation are provided with the same reference symbols in the figures.

1 shows an injector/ejector 16 with a valve 11 according to a possible embodiment. The injector/ejector 16 is designed in the form of a jet pump. The valve 11 is designed as part of the injector/ejector 16. The injector/ejector 16 and the valve 11 have a common housing. The valve 11 has a control means 19, a valve seat 22 and a valve volume 23. The control means 19 has a valve tappet 20 and a valve plate 21. The valve plate 21 can, depending on the valve position, be positioned on the valve seat 22 or spaced from the valve seat 22. In a closed valve position, the valve plate 21 is located on the valve seat 22. In an open valve position, the valve plate 21 is spaced from the valve seat 22. In a maximum open valve position, the valve opening, in this case an annular gap 29, forms the smallest flow cross-section of the injector/ejector 16. As a result, the mass flow through the annular gap is always supercritical.

The valve 11 is designed as a magnetically operated proportional valve. As with regard to 1 As can be seen, a fuel supply path 24 leads to the valve 11 and thus into the drive area of the injector/ejector 16. An anode gas supply path 25 leads from a diffuser area of the injector/ejector 16 away from the injector/ejector 16. A recirculation path 27 leads to a suction area of the injector/ejector 16.

2 shows a device 10 configured as part of a fuel cell system. The device 10 comprises a fuel cell 12 with an anode 13 and a cathode 14. The device 10 further comprises a fuel supply path 24, an anode gas supply path 25 and the 1 The device 10 includes an injector/ejector 16 shown for supplying anode gas to the anode 13 through the anode gas supply path 25. The valve 11 is configured as part of the injector/ejector 16. The device 10 also includes a process gas outlet path 26, a water separator 18, a recirculation path 27, an exhaust gas path 28, and a purge valve 17. Furthermore, the device 10 includes a controller 70. The controller 70 can be configured as an ECU and/or as part of a vehicle control unit.

3 shows a hysteresis of the valve 11. The X-axis represents the electric current and the Y-axis represents the valve opening degree or valve position. With reference to 3 and 4 A method for adjusting the valve 11 is then explained. In a first step S1, the electrical control current I, with which the valve 11 is controlled, is periodically varied. In a second step S2, the varying control current I is converted into an average current component by means of Reynolds decomposition I and decomposed into a varying current component I'(t). Here: I = I + I'(t). In a third step S3, an averaged valve position $\overline{Vent}$ based on the averaged current part I determined or calculated. In a fourth step S4, the valve 11 is controlled based on the average valve position $\overline{Vent}$ adjusted or regulated. Steps S1 to S4 do not have to be performed in the order shown. Steps S1 to S4 can be performed at least partially simultaneously. As with regard to 3 As can be seen, the hysteresis of the valve 11 can be circumvented by varying the control current I. This allows each averaged current part I clearly an averaged valve position $\overline{Vent}$ or a corresponding mass flow can be assigned.

In the method presented, the amplitude for the varying current component I'(t) is continuously reduced during a variation time in which the drive current is varied. Initially, the drive current is varied at a value of 50 mA and a frequency of 1 Hz and is then continuously reduced to a predefined current value.

5 shows a computer-readable and non-volatile storage medium 40 on which a computer program product 30 is stored. The storage medium 40 is configured in the form of a flash drive. The computer program product 30 comprises instructions that, when executed by a computer, cause the computer to execute the described method in the device 10 shown. The computer can be understood as the controller 70 described above.

In 6 A vehicle 100 in the form of a passenger car is shown. The vehicle 100 has a device 10 as described above as part of a fuel cell system. The vehicle 100 further has two electric motors 50 for driving the vehicle 100, wherein the fuel cell system is configured to supply power to the electric motors 50. Furthermore, the vehicle 100 has a fuel-filled pressure vessel 60 for supplying fuel to the fuel cell system or device 10. Furthermore, the vehicle 100 has a controller 70 configured to carry out the method described above.

The technology disclosed here allows for further design principles in addition to the embodiments shown. This means that the technology should not be considered limited to the embodiments explained with reference to the figures.

List of reference symbols

10

device

11

valve

12

fuel cell

13

anode

14

cathode

16

Injector/Ejector

17

Flush valve

18

Water separator

19

Control means

20

valve tappet

21

valve plate

22

valve seat

23

Valve volume

24

Fuel gas supply path

25

Anode gas supply path

26

Process gas outlet path

27

Recirculation path

28

Exhaust path

29

Ejector outlet area

30

computer program product

40

Storage medium

50

electric motor

60

pressure vessel

70

Controller

100

vehicle

Claims (10)

A method for adjusting a magnetically controllable valve (11), comprising: - varying an electrical control current with which the valve (11) is controlled, - decomposing the varying control current into an averaged current part and a varying current part, - determining an averaged valve position based on the averaged current part, and - adjusting the valve (11) based on the averaged valve position. Procedure according to Claim 1 , whereby the electrical control current is varied periodically. Method according to one of the preceding claims, wherein the amplitude for the varying current part is continuously reduced during a variation time in which the drive current is varied. Method according to one of the preceding claims, wherein the drive current is varied with a value in a range between 1 mA and 100 mA. Method according to one of the preceding claims, wherein the drive current is varied at a frequency in a range between 0.1 Hz and 10 Hz. A device (10) comprising a magnetically controllable valve (11), wherein the device (10) is configured to: - vary an electrical control current with which the valve (11) is controlled, - decompose the varying control current into an averaged current portion and a varying current portion, - determine an averaged valve position based on the averaged current portion, and - adjust the valve (11) based on the averaged valve position. Device (10) according to Claim 6 , comprising a fuel cell (12) with an anode (13) and a cathode (14), an anode gas supply path (25) and an injector/ejector (16) for supplying anode gas to the anode (13) through the anode gas supply path (25), wherein the valve (11) is designed as part of the injector/ejector (16). Vehicle (100) with a device (10) according to one of the Claims 6 until 7 , wherein the device (10) is configured to generate electrical power in the vehicle (100). Computer program product (30), comprising instructions which, when the computer program product (30) is executed by a computer, cause the computer to execute, in a device (10) according to one of the Claims 6 until 7 the procedure according to one of the Claims 1 until 5 to execute. Computer-readable storage medium (40) having a computer program product (30) stored thereon according to Claim 9 .