DE102021202116B4 - Device for the controllable dosing of hydrogen and method for producing the same - Google Patents

Abstract

Device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive, the device having a valve seat (7), a sealing element (17) and an electromagnetic actuator with a pole core (11), a magnetic coil (2) and one with the sealing element (17) coupled armature (16), wherein the actuator is configured to move the sealing element (17) along an axis (A) in response to an electric current in the magnetic coil (2), the sealing element (17) having an axially in direction towards the valve seat (7) tapering surface, which has at least a first portion (171) with a first angle of inclination relative to the axis (A) and a second portion (172) with a second angle of inclination relative to the axis (A), wherein a surface of the pole core (11) and a surface of the armature (16) together form a double cone, wherein the surface of the pole core (11) has at least a first pole core surface area (111) with a first pole core cone angle and a second pole core surface area (112) with a second pole core cone angle, and wherein the surface of the armature (16) has at least a first armature surface area (161) with a first armature cone angle and a second armature surface area (162) having a second armature cone angle, wherein the first pole core cone angle is equal to the first armature cone angle, and/or wherein the second pole core cone angle is equal to the second armature cone angle, and wherein the coil (2) through a sleeve (3) is separated from the pole core (11) and armature (16).

Description

The present invention relates to the technical field of using hydrogen and fuel cells in connection with vehicle engines. The present invention relates in particular to a device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive. The present invention also relates to a method for manufacturing such a device.

JP S60 - 241 586 A describes a needle valve suitable for advancing to and separating from a valve seat of an expansion valve and driven by a stepping motor. The needle valve has a tapered peripheral surface portion with a large valve angle at its extreme end and continuously has a tapered peripheral surface portion with a small valve angle, whereby the boundary portion is an inflection point for admitting the needle valve. The needle valve has a two-slope flow characteristic. A tapered peripheral surface portion with a large valve angle is disposed on the inside of the tapered peripheral surface portion because the tapered peripheral surface portion A with such a small valve angle tends to intrude into the valve seat upon closing.

U.S. 2004/0 257 185 A1 describes a variable force solenoid, the solenoid having a relatively long stroke and a relatively low profile. The electromagnet has an armature with at least one conical surface and a pole piece with at least one conical surface. The armature and pole piece may each be provided with multiple tapers on more than one surface thereof.

The present invention is generally based on the task of providing a precise, efficient and reliable control of hydrogen supply to fuel cells and in particular of achieving a large control range for a targeted, precise metering of hydrogen while at the same time having a high quality in small quantities.

This object is solved by the subject matter of the independent patent claims. Advantageous embodiments of the present invention are described in the dependent claims.

According to a first aspect of the invention, a device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive, is described. The device described has the following: a valve seat, a sealing element and an electromagnetic actuator with a pole core, a magnetic coil and an armature coupled to the sealing element, wherein the actuator is configured to move the sealing element along an axis in dependence on an electric current in the magnetic coil is. The sealing element has an axially tapering surface towards the valve seat, which has at least a first section with a first angle of inclination relative to the axis and a second section with a second angle of inclination relative to the axis.

The device described is based on the knowledge that the design of the sealing element with at least two surface sections with an individual angle of inclination enables precise and needs-based regulation of the hydrogen volume flow. The angle of inclination directly determines the relationship between change in effective valve opening and change in armature lift. The larger the angle of inclination, the smaller the change in effective valve opening for a given change in armature lift. The sealing element formed in this way thus enables, in particular, different relationships between the effective valve opening and armature movement in different operating states, such as for example when the valve is opening/closing and when the valve is open.

According to an embodiment of the invention, the first section is closer to the valve seat than the second section and has a smaller angle of inclination than the second section.

In other words, the angle of inclination of the second section determines the effective valve opening at or shortly after opening of the valve, while the angle of inclination determines the effective valve opening when the valve is open.

According to another embodiment of the invention, the tapered surface has a third section with a third angle of inclination relative to the axis.

By adding a third section with a third angle of inclination, the relationship between change in effective valve opening and armature movement can be further designed. If necessary, further sections with appropriate inclination angles can be added.

According to a further exemplary embodiment of the invention, the device has a characteristic curve which represents a relationship between the mass flow and the coil current and which has at least two linear sections, each with a different slope.

The two linear sections of the characteristic correspond in particular to the first and second section of the surface of the sealing element. If there are more than two surface sections with individual angles of inclination, the characteristic curve will have correspondingly more linear sections with individual gradients.

According to a further exemplary embodiment of the invention, the electromagnetic actuator is arranged on a high-pressure side of the device.

This arrangement ensures that the actuator is in the dry hydrogen area and is therefore well protected against ice formation that can occur on the low-pressure side.

According to the invention, a surface of the pole core and a surface of the armature together form a double cone.

In other words, both the surface of the pole core and the surface of the armature each have a cone shape. In particular, the two conical surfaces are designed in such a way that the conical surface of the pole core fits into the conical surface of the armature. This double cone provides a largely linearized actuator that has good controllability over a relatively large working range.

According to the invention, the surface of the pole core has at least a first pole core surface area with a first pole core cone angle and a second pole core surface area with a second pole core cone angle, and the surface of the armature has at least a first armature surface area with a first armature cone angle and a second armature surface area with a second anchor cone angle.

In this context, the term "cone angle" is to be understood in particular as the angle between the axis and the cone surface.

In other words, both the pole core cone and the armature cone each have two surface areas with different cone angles. Depending on the stroke of the magnet, the magnetic field lines are deflected differently for the linearization. As a result, the characteristic curve can be shaped in such a way that the control accuracy (gradient of the characteristic curve) is adapted to the requirements of the fuel cell. In particular, a corresponding segmentation of the characteristic curve can be achieved with a gradation of the cone surfaces.

According to a further exemplary embodiment of the invention, the first pole core surface area and the first armature surface area are each closer to the sealing element than the second pole core surface area and the second armature surface area, and the first pole core cone angle and the first armature cone angle are each smaller than the second pole core cone angle and the second anchor cone angle.

In other words, the first pole core surface area and the first armature surface area are steeper than the second pole core surface area and the second armature surface area. In particular, this leads to a flatter characteristic curve at smaller valve openings than at larger valve openings and consequently enables more precise control of the hydrogen supply during opening and shortly after opening of the valve.

According to the invention, the first pole core cone angle is equal to the first armature cone angle, and/or the second pole core cone angle is equal to the second armature cone angle.

In other words, the cone shape of the pole core largely corresponds to the cone shape of the armature.

According to a second aspect of the invention, a method for producing a device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive, is described. The method described includes: (a) providing a valve seat, (b) providing a sealing element, and (c) providing an electromagnetic actuator having a pole core, a magnetic coil, and an armature coupled to the sealing element, the actuator being used to move the sealing element along an axis in response to an electric current in the magnetic coil, wherein the sealing element has an axially tapering surface towards the valve seat, which has at least a first section with a first angle of inclination relative to the axis and a second section with a second angle of inclination relative to the axis.

The method described is essentially based on the same idea as the device described above and in particular provides a method for producing such a device.

It is pointed out that embodiments of the invention have been described with reference to different objects of the invention. In particular, some embodiments of the invention are provided with method claims and other embodiments of the invention are provided with pros directional claims described. However, it will be immediately clear to those skilled in the art upon reading this application that, unless explicitly stated otherwise, any combination of features belonging to different types of subject matter is also possible in addition to a combination of features belonging to one type of subject matter objects of the invention.

• 1 zeigt ein System zur Wasserstoffversorgung einer Brennstoffzelle.
• 2 zeigt eine Prinzipdarstellung eines Ventils.
• 3 zeigt eine Kennlinie eines Ventils.
• 4 zeigt eine erfindungsgemäße Vorrichtung zur regelbaren Dosierung von Wasserstoff an eine Brennstoffzelle.
• 5 zeigt eine Detailansicht eines pneumatischen Bereichs einer erfindungsgemäßen Vorrichtung mit zugehöriger Kennlinie.
• 6 zeigt eine Detailansicht eines Bereichs zur Magnetkrafterzeugung einer erfindungsgemäßen Vorrichtung mit zugehöriger Kennlinie.

Further advantages and features of the present invention result from the following exemplary description of a preferred embodiment.

• 1 shows a system for supplying hydrogen to a fuel cell.
• 2 shows a schematic diagram of a valve.
• 3 shows a characteristic of a valve.
• 4 shows a device according to the invention for the controllable metering of hydrogen to a fuel cell.
• 5 shows a detailed view of a pneumatic area of a device according to the invention with the associated characteristic curve.
• 6 shows a detailed view of an area for generating magnetic force of a device according to the invention with the associated characteristic curve.

It is pointed out that the embodiments described below only represent a limited selection of possible embodiment variants of the invention.

First, with reference to the 1 until 3 a system for supplying hydrogen to a fuel cell and in particular the requirements of such a system with regard to regulation. Furthermore, some of the considerations and ideas on which the present invention is based are presented.

the 1 shows a system 100 for supplying hydrogen to a fuel cell. When fuel cells 114 are used, hydrogen from the hydrogen tank 102 is provided in gaseous form at a pressure of approximately 350 bar to 700 bar for the application. In order to prevent an uncontrolled escape in the event of a fault, a shut-off valve 104 is arranged immediately after the tank 102 . In the further course, the high pressure from the tank 102 is reduced by means of a pressure reducer 106 to a lower pressure level, the medium pressure range, with approximately 10 bar to 30 bar. Within this pressure stage, the hydrogen is fed in lines 108 to the area of hydrogen metering to the anode A of the fuel cell 114 .

The hydrogen is metered in in a targeted manner through the valve 110 for the hydrogen metering. The pressure (low pressure) inside the anode A is in the range of approx. 0.8 bar to 4 bar. A hydrogen mass flow is set in valve 110 with the pressure drop from medium pressure to low pressure. The pressure in the anode A, a closed volume, is initially regulated in such a way that this volume is filled with a defined mass flow of hydrogen. A defined pressure is set in the volume of the anode A area.

The hydrogen reacts in the fuel cell 114 with the oxygen from the cathode side K. The oxygen in the cathode side K is supplied via the separate supply unit 116, which ensures that sufficient oxygen with a defined pressure in the area of the cathode K is available in this area . An excess of oxygen can escape or be discharged via the outlet 118 .

Over time, nitrogen and water diffuse through the membrane from the cathode side K to the anode side A. These block the channels of the hydrogen path and thus prevent the even distribution of hydrogen over the entire membrane. To prevent this, the gas within the anode area A is recirculated. This can be done by a gas blower 124 or an ejector 112. Here, the gas from the outlet 126 of the anode A of the fuel cell 114 is fed to the inlet 128 of the anode A again. This results in gas exchange within the anode A. Unused hydrogen, nitrogen and water are thus pumped out of the stack and fed back in.

The recirculation increases the proportion of nitrogen and water in the hydrogen path. Water can be separated by a water separator 120 in the recirculation. Nitrogen is purged by actuating purge valve 122 . By dosing new hydrogen, the valve 110 keeps the pressure difference between the anode side and the cathode side constant during the flushing process.

To regulate this pressure difference, the pressure on the anode and cathode side is measured by sensors. The electronic control adjusts the hydrogen metering valve 110 via a control algorithm in such a way that the pressure in the anode A is regulated in the defined range and the required pressure difference between the anode A and the cathode K for the reaction of the two gases is present.

1. 1. Regelung und Steuerung des Wasserstoffs in einem möglichst großen Regelbereich.
2. 2. Hohe Regelgüte in den Hauptbetriebsbereichen der Brennstoffzelle 114.
3. 3. Hohe Regelgüte bei Kleinstmengen.
4. 4. Keine Geräuschentwicklung.
5. 5. Stromlos geschlossen: bei Unterbrechung des Steuersignals soll Ventil 110 geschlossen sein
6. 6. Schutz der Membran auf der Anodenseite A bei Überdruck im Zulaufbereich des Wasserstoffdosierventils 110.
7. 7. Regelbarkeit im Kaltstartbereich.
8. 8. Keine Beschädigung des Magneten durch einfrierendes Wasser.
9. 9. Dichtigkeit des Magneten zur Umwelt - keine externe Leckage.

The requirements for such a hydrogen metering valve 110 are as follows, all requirements applying simultaneously:

1. 1. Regulation and control of the hydrogen in the widest possible control range.
2. 2. High control quality in the main operating ranges of the fuel cell 114.
3. 3. High control quality with small quantities.
4. 4. No noise.
5. 5. Normally closed: when the control signal is interrupted, valve 110 should be closed
6. 6. Protection of the membrane on the anode side A in the event of overpressure in the inlet area of the hydrogen metering valve 110.
7. 7. Controllability in the cold start area.
8. 8. No damage to the magnet from freezing water.
9. 9. Magnet tightness to the environment - no external leakage.

Volume flow control valves, or rather for fuel cell technology mass flow control valves for supplying the anode A and controlling the anode pressure, are valves in which a cross-section is closed or released via a directly controlled magnet. An optimal design for such a valve is derived below. The aim for the function is the first three requirements mentioned above (large control range, high control quality in the main operating areas and for very small quantities).

The main element for dimensioning is the pneumatics with valve seat and sealing element. In the 2 shows the geometric conditions of a pneumatic area.

• • Keine Querschnittfreigabe - das Ventil soll abdichten - der Hub des Dichtelements
• • kontinuierlicher Massestrom - über ein Ventilelement soll ein definierter Querschnitt vorhanden sein
• • maximaler dauerhafter Massestrom, bei einem maximalen dauerhaften Querschnitt.

With regard to the design, a cross-section of the valve should assume the following states:

• • No cross-section release - the valve should seal - the stroke of the sealing element
• • Continuous mass flow - a defined cross-section should be present via a valve element
• • maximum permanent mass flow, with a maximum permanent cross-section.

The sealing element DE can assume different positions in the valve lift s. When closed (s=0 mm), the sealing element DE with the seat diameter dS sits on the valve seat VS. There is no flow through the valve in this condition. The valve seals. The force F on the sealing element DE is calculated using the pressure area formed by the seat diameter dS and the pressure difference on both sides of the sealing element.

With an increase in the valve lift s, the cross-section through which flow occurs increases with a value x, approximately the line perpendicular to the valve seat surface up to the point of the seat diameter dS. The value x corresponds to the length of the lateral surface of a truncated cone. The direction of flow results from the pressure difference across the sealing element DE.

This cross-section of the truncated cone with the lateral surface length x is effective as long as this surface is smaller than the cross-section of the hole dB. With larger valve lifts s, the cross-section of the bore dB is effective.

When designing, there are three parameters between which an optimum must always be found. The bore diameter dB defines the maximum possible mass flow. Then the minimum required lift is defined, at which the cross-sectional area between the sealing element DE and the valve seat VS is just not yet effective. With the valve seat angle α, the cross-sectional area in the stroke can be adjusted according to the requirements, while at the same time the condition of the effectiveness of the area of the bore diameter dB must be observed.

Selection parameters for the actuator are the required force of the sealing element DE in the closed state and the required valve lift s, which corresponds to the magnet lift in a directly controlled valve.

The aim of the pneumatics is to have a large effective valve lift for the most precise control possible in the largest possible range, with the largest possible mass flow-defining orifice with a diameter dB and a large resulting pneumatic force in the closed state.

The aim of the pneumatics is in direct conflict with the choice of the actuator with the smallest possible installation space, in which the stroke must be as small as possible in order to obtain sufficient force as a function of the actuator stroke.

The most important requirement for the selection of the actuator is (see No. 4 above): No noise development - continuous and permanent release of a defined cross-section.

When choosing the magnet, a switching magnet (with only two switching positions, for example that of an injector) can be ruled out from the point of “no noise development”. The first reason is the noise generated when shifting gears. The second reason is that these magnets are designed for high switching speed. On the one hand, this means that the resistance is low (quick current increase when voltage is applied). This would cause it to overheat if it was energized for a long time. On the other hand, even if the resistance were higher, the magnet stroke is too small. In the case of switching magnets, the force decreases sharply with larger pole distances δ. In this case, the current required to generate the power would be very high, and the risk of the coil overheating would therefore exist. To prevent overheating, one would have to temporarily turn off the magnet, which would result in a temporary plugging of the bore. The consequence would be a larger bore and again a larger magnet in order to be able to hold the pneumatic forces with a larger bore.

With linearization, the magnetic force is weakened compared to a switching magnet for small magnet strokes and increased for larger magnet strokes. As a result, the total stroke of a magnet can be increased, the magnetic force can be adapted to the pneumatics and the usable work can be increased. The linearization becomes difficult if the magnet has to be pressure-balanced in the interior and external tightness has to be ensured, and the design of the magnet has to be small.

Control is usually via a "direct current". Since the vehicle only has voltage from a battery, this voltage is converted into direct current using pulse width modulation. With a suitable design of a linearized magnet, a characteristic map can be generated for the actuator in which the magnetic force only depends on an applied current level. If such a linearized magnet works against a compression spring and the pneumatic forces, a magnet system can be set up with such a characteristic, in which the path is directly dependent on the set current level. The frequency for the pulse width modulation then determines the ripple of this direct current. Since the magnetic force is directly dependent on the current, an oscillating movement is generated by the current ripple. The armature is moved towards the counter bearing by the vibration in a state with sliding friction. As a result, the friction in the system and thus the hysteresis of the functional characteristic can be kept low.

The proportional magnet is also advantageous from a thermal point of view. In addition to the pressure and mass flow functions, the boundary condition is that the magnet is not thermally overloaded in a large ambient temperature range. The aim is that the pneumatics can be kept permanently open with a defined direct current without being thermally overloaded. Coil resistance is low at low temperatures and increases at higher temperatures. Based on the ambient temperature, the electrical power introduced further heats the coil resistance. The coil wire temperature must not exceed a certain value (e.g. 200°C), otherwise the insulation of the coil wire could be damaged. On this basis, a maximum control range of the characteristic can be defined up to a current Imax, at which the full mass flow can be set and on the other hand the coil is not thermally damaged.

After the pneumatic design of the magnet, another requirement for the valve is the operating mode, so that no damage occurs in the event of a fault or emergency running properties are available. In this case, it is defined that in the event of an error, if there is no electrical signal (failure of electronics, damage to the wiring harness, connector or coil burnout), there must be no mass flow to the stack in order to prevent damage to the stack. The requirement from the above list of requirements is (see No. 5 above) that the must be closed when de-energized. There are several options for constructing such a valve, which differ in particular in the direction of the magnetic force, the force of the compression spring and the pneumatic force.

If you look at the next requirement (see No. 6 above), i.e. protection of the membrane on the anode side in the event of overpressure in the inlet area of the hydrogen metering valve, only the concepts in which there is no opening pressure from the pneumatics meet this requirement. This means that the valve element cannot be pushed open by the pneumatics due to an increase in pressure. As a result, no or only small amounts of medium can get into the anode area, so that the membrane in the anode is protected from overpressure.

In view of the last two requirements (see Nos. 7 and 8 above), it now follows that the actuator must be in the area of the dry hydrogen in the inlet. In addition to the dosed hydrogen and nitrogen, there is also water vapor and deionized water on the low-pressure side. If these media were to be present in the area of the actuator, frozen water in the area of the moving parts could affect controllability in the cold starting area severely restricted, if not even available. Since water expands when it freezes, if water freezes in the area of the magnet, the volume expansion could damage the magnet.

These considerations lead to the following result: The medium is fed in in the area of the magnet. This protects the magnet from freezing. The pressure difference prevents the medium from reaching the anode in the event of a fault. By choosing the proportional magnet, the electrical power can be limited and the aperture can be opened permanently. As a result, the magnet can be operated almost silently, with almost no mechanical stress on the valve element. The functional characteristic (relationship between mass flow m 'and coil current) of such a valve is in the 3 shown. If there is a pressure difference between the inlet and outlet and no electrical current is applied, the valve element is closed with the pneumatic force. At this point there is no mass flow. If the electric current is increased, there is an equilibrium of forces between the pneumatic force, the force of the compression spring and the magnetic force at the point lopen. The valve starts to open. At Imax, the maximum control range defined by the design, the minimum required mass flow must be present at a defined pressure difference at the valve to supply the anode when the fuel cell is fully utilized.

The goal for precise control is the lowest possible opening current lopen and the flattest possible characteristic curve to point Imax, with the characteristic curve of the valve also being adapted to the requirements of the fuel cell.

• • einen möglichst großen wirksamen Hub im Bereich der Pneumatik,
• • einen Magneten mit einem möglichst großen Hub und einer möglichst großen vorhandenen Magnetkraft und
• • darüber hinaus auch Möglichkeiten zur Formung der Kennlinie in einem Kräftegleichgewicht zwischen pneumatischen Kräften, magnetischen Kräften und mechanischen Kräften, die abhängig von einem Weg (Hub) sind.

This goal requires

• • the largest possible effective stroke in the field of pneumatics,
• • a magnet with the greatest possible stroke and the greatest possible existing magnetic force and
• • In addition, options for forming the characteristic curve in a force balance between pneumatic forces, magnetic forces and mechanical forces that are dependent on a path (stroke).

The problem with these valves is the conflict of objectives between the relatively high pressures in the medium-pressure line due to the relatively high required mass flows and the associated inlet orifice, the design to fulfill the required functions and the limited installation space, including the requirement that the magnet be pressure-balanced in the interior and must be sealed from the environment.

The aim on which the present invention is based is to achieve a large control range for targeted, precise hydrogen metering while at the same time having a high quality in small quantities. In this control range, the gradient is increasing. The inlet orifice cross-section should not be effective in the characteristic curve of the control range, only in the case of the maximum control current. This means that the characteristic curve should not be approximately horizontal above the control range.

the 4 shows a device according to the invention for the controllable metering of hydrogen to a fuel cell. The device shown has in particular a pneumatic area with a sealing element 17 and a valve seat 7 and an electromagnetic actuator with a pole core 11 , an armature 16 and a coil 2 . The pole core 11 forms a double cone together with the armature 16, ie both the pole core 11 and the armature 16 have surfaces which are oblique or inclined by a cone angle relative to the axis. The armature 16 is coupled to the sealing element 17 via a centering pin 15 and a pin 5, so that an axial movement of the armature leads to a corresponding axial movement of the sealing element 17. Electrical current is applied to the coil 2 via a connection 1 and is separated from the pole core 11 and armature 16 by a sleeve 3 in the interior of the area 12 generating the magnetic force. The sleeve 3 serves as a seal against the environment. The device also has a housing 4 in which a lateral inlet 6 and a bottom outlet 8 are provided for the hydrogen. A yoke 9 and a tube 10 are also provided in the upper area of the device.

An important aspect of the present invention resides in the design of the pneumatic section. the 5 shows a detailed view of the pneumatic area in the 4 shown device according to the invention with associated characteristic. The sealing element 17 has a surface which tapers axially towards the valve seat 7 and which has a first section 171 with a first angle of inclination relative to the axis A and a second section 172 with a second angle of inclination relative to the axis A. In further embodiments, even more sections with individual angles of inclination can be provided. The first section 171 is located in the lower end area of the sealing element 17 and is therefore closer to the valve seat 7 than the second section 172. Furthermore, the first angle of inclination is smaller than the second angle of inclination. When the valve is closed, the sealing element 17 is so deep in the valve seat that the surfaces are tight lie against each other. When the valve opens, the change in size of the opening between the valve seat 7 and the sealing element 17 is first determined by the section 172 as the axial movement of the sealing element increases upwards. This corresponds to the section K2 in the left part of the 5 shown characteristic. When the coil current reaches the value I1 and the sealing element is positioned at the corresponding height, the change in size is determined by section 171 in the further course. This corresponds to section K1, which is steeper due to the smaller angle of inclination, in the left-hand part of FIG 5 shown characteristic. At the latest when the coil current reaches the maximum value Imax, the mass flow is equal to the minimum required mass flow. The gradation in the shape of the sealing element 17 thus leads to a corresponding gradation in the shape of the characteristic curve and in particular ensures that precise control is possible at both low and high mass flows.

the 6 shows a detailed view of a region 12 for generating magnetic force of a device according to the invention with the associated characteristic. The above in connection with the 5 The stepped characteristic curve explained above is achieved with a double cone in the area of magnetic force generation. A further gradation of the characteristic can be done with the in 6 shown design of the double cone can be achieved. The surface of the pole core 11 has a first pole core surface area 111 with a first pole core cone angle and a second pole core surface area 112 with a second pole core cone angle. The surface of anchor 16 similarly includes a first anchor surface area 161 having a first anchor cone angle and a second anchor surface area 162 having a second anchor cone angle. In combination with the in connection with the 5 explained gradation of the sealing element, an additional gradation of the characteristic can be achieved. This is in the on the left part of the 6 shown characteristic, which has three characteristic curve sections K1, K2, K3 with different inclination to recognize. A desired control accuracy (slope of the characteristic curve) can thus be provided in different areas.

Claims (7)

Device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive, having the device a valve seat (7), a sealing element (17) and an electromagnetic actuator having a pole core (11), a magnetic coil (2) and an armature (16) coupled to the sealing element (17), the actuator for moving the sealing element (17) along an axis (A) in dependence on an electric current is configured in the magnetic coil (2), wherein the sealing element (17) has a surface tapering axially in the direction of the valve seat (7) and having at least a first section (171) with a first angle of inclination relative to the axis (A) and a second section (172) with a second angle of inclination relative to the axis (A), wherein a surface of the pole core (11) and a surface of the armature (16) together form a double cone, wherein the surface of the pole core (11) has at least a first pole core surface area (111) with a first pole core cone angle and a second pole core surface area (112) with a second pole core cone angle, and wherein the surface of the armature (16) has at least a first armature surface area ( 161) with a first anchor cone angle and a second anchor surface area (162) with a second anchor cone angle, wherein the first pole core cone angle is equal to the first armature cone angle, and/or wherein the second pole core cone angle is equal to the second armature cone angle, and the coil (2) being separated from the pole core (11) and armature (16) by a sleeve (3). The device according to claim 1 , wherein the first section is closer to the valve seat than the second section and has a smaller angle of inclination than the second section. The device according to claim 1 or 2 wherein the tapered surface has a third section with a third angle of inclination relative to the axis. The device according to one of the preceding claims, having a characteristic showing a relationship between mass flow and coil current, which has at least two linear sections (K1, K2) each with a different slope. The device according to any one of the preceding claims, wherein the electromagnetic actuator is arranged on a high-pressure side of the device. The apparatus of any preceding claim, wherein the first pole core surface area and the first armature surface area are each closer to the sealing member than the second pole core surface area and the second armature surface area, and wherein the first pole core cone angle and the first armature cone angle are each smaller than the second pole core cone angle and the second armature cone angle. Method for producing a device for the controllable metering of hydrogen to a fuel cell, in particular in a vehicle with an electric drive, comprising the method providing a valve seat, providing a sealing element and providing an electromagnetic actuator having a pole core, a magnetic coil, and an armature coupled to the sealing element, the actuator being configured to move the sealing element along an axis in response to an electrical current in the magnetic coil, wherein the sealing element has a surface tapering axially towards the valve seat, which surface has at least a first section with a first angle of inclination relative to the axis and a second section with a second angle of inclination relative to the axis, wherein a surface of the pole core (11) and a surface of the armature (16) together form a double cone, wherein the surface of the pole core (11) has at least a first pole core surface area (111) with a first pole core cone angle and a second pole core surface area (112) with a second pole core cone angle, and wherein the surface of the armature (16) has at least a first armature surface area ( 161) with a first anchor cone angle and a second anchor surface area (162) with a second anchor cone angle, wherein the first pole core cone angle is equal to the first armature cone angle, and/or wherein the second pole core cone angle is equal to the second armature cone angle, and the coil (2) being separated from the pole core (11) and armature (16) by a sleeve (3).

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