Jet pump comprising a fluid valve, and fuel cell

Abstract

The invention relates to a jet pump (10) for a fuel cell that can be operated with fuel gas, comprising an outlet port (12) for discharging a fuel gas fluid containing the fuel gas to the fuel cell, a circulation inlet (14) for recirculating a recirculation fluid, which remains in the fuel cell upon processing of the fuel gas fluid, from the fuel cell, and a fuel gas inlet (16), which can be connected to a fuel gas supply, for introducing the fuel gas (24), a mixing chamber (20) which connects the circulation inlet (14) to the outlet port (12), a jet pump nozzle (26) which allows the fuel gas to be discharged into the mixing chamber (20) from the fuel gas inlet (16) via an inlet-side inlet region (22) and a nozzle outlet port (24) adjacent thereto, wherein the nozzle outlet port (24) can be adjusted depending on a stroke position of a stroke element (30), and a fluid valve (48) is placed between the fuel gas inlet (16) and the inlet region (22) so as to be effective in respect of a flow of the fuel gas. The invention also relates to a fuel cell.

Description

[0001] Jet pump with a fluid valve and fuel cell

[0002] Description introduction

[0003] The invention relates to a jet pump according to the preamble of claim 1. The invention further relates to a fuel cell.

[0004] German patent DE 102021 111 661 A1 describes a jet pump for a fuel cell. The jet pump comprises a jet pump nozzle for injecting a fuel gas into a mixing chamber. The jet pump draws in a recirculating gas mixture for mixing with the fuel gas in the mixing chamber.

[0005] The object of the present invention is to make the fuel gas recirculation and the injection control more space-saving and efficient.

[0006] At least one of these tasks is solved by a jet pump with the features according to claim 1. This allows the fuel gas to be supplied to the fuel cell in a more energy-efficient manner. The control of the fuel gas flow can be implemented in a more space-saving and efficient way.

[0007] The fuel cell can be located in a vehicle or industrial equipment. The fuel cell can supply energy for propelling the vehicle, at least partially, and in particular primarily.

[0008] The fuel cell can comprise at least one membrane electrode assembly with at least one anode, at least one cathode, and at least one membrane. The membrane can be a proton exchange membrane (PEM). The membrane can be a polymer membrane. The membrane electrode assembly can comprise a fuel cell stack.

[0009] The anode can be arranged in an anode circuit for supplying the fuel gas fluid to the anode.

[0010] The fuel gas can be hydrogen or consist mainly of hydrogen.

[0011] The fuel gas can be present at the fuel gas inlet at a supply pressure. The processing of the fuel gas fluid in the fuel cell can involve an electrochemical reaction of the fuel gas, particularly with atmospheric oxygen.

[0012] The outlet opening can be fluid-transferred to an input side of the fuel cell's anode circuit. The circulation inlet can be fluid-transferred to an output side of the anode circuit.

[0013] The jet pump nozzle can generate a motive jet containing the fuel gas. This jet can create a vacuum at the circulation inlet to draw off the return fluid at the anode circuit outlet. The jet pump can also function as a passive circulation pump for the circulation circuit, particularly within the anode circuit.

[0014] In the mixing chamber, the fuel gas and the return fluid can be mixed to form the fuel gas fluid. The propellant jet can also be combined with the return fluid in the mixing chamber.

[0015] The entrance area can be a nozzle chamber.

[0016] The fluid valve can be normally closed (closed when de-energized).

[0017] The nozzle outlet opening can be adjustable by changing the cross-sectional area of ​​the nozzle outlet opening.

[0018] The lifting element can be axially displaceable along an axial axis. The lifting element can be displaceable by at least one actuator element. The actuator element can be a solenoid, a linear motor, or a stepper motor. The lifting element can adjust the output pressure of the fuel gas at the nozzle outlet via the adjustable nozzle opening. This allows the lifting element to form a pressure regulating valve with the jet pump nozzle.

[0019] The fuel gas fluid can consist of a mixture of the fuel gas and the return fluid. The return fluid can be the excess fuel gas fluid derived from, in particular, the anode circuit of the fuel cell, which is preferably dehydrated or dehumidified before being fed to the jet pump. Due to a superstoichiometric proportion of the fuel gas fluid supplied to the fuel cell, the return fluid entering the fuel cell via the circulation inlet can be diverted away from the fuel cell as the excess portion not participating in the reaction, particularly the electrochemical reaction, within the fuel cell, and be present at the circulation inlet. In a preferred embodiment of the invention, it is advantageous if a transition opening for the fuel gas flow between the fuel gas inlet and the inlet region is adjustable depending on the position of the fluid valve.The fluid valve can be a shut-off valve, particularly to cut off the fuel gas supply to the inlet area. The fluid valve can adjust the transition opening continuously or abruptly. The fluid valve can open or close the transition opening. The fluid valve can only assume two valve positions: open or closed. The fluid valve can set multiple opening states of the transition opening through respective valve positions. The transition opening can be adjustable by allowing a change in the cross-sectional area of ​​the transition opening.

[0020] A preferred embodiment of the invention is advantageous in which the transition opening is located upstream of the nozzle outlet opening with respect to the fuel gas flow. The transition opening can be fluid-transferred to the inlet region via at least one fluid channel. The transition opening can also be fluid-transferred to the fuel gas inlet via at least one fluid channel.

[0021] In a particular embodiment of the invention, it is advantageous if the fluid valve has at least one valve element whose transition opening can be varied depending on the valve position and which is coupled to the lifting element. The valve element and the lifting element can be rigidly connected to each other. The valve element and the lifting element can be connected to each other by positive locking, force locking, and / or material locking. The valve element and the lifting element can be manufactured as a single unit.

[0022] The valve element can be axially displaceable along a further axial axis or along the axial axis itself. The valve element and the lifting element can be arranged coaxially with respect to the axial axis.

[0023] The valve element can include a valve disc. The valve element, in particular the valve disc, can be sealed against a sealing area by at least one sealing element, depending on the valve position. The sealing element can be a sealing ring or an O-ring. The sealing element can be positively, mechanically, and / or materially connected to the valve element and / or the sealing area.

[0024] In a preferred embodiment of the invention, the valve position and the stroke position are interdependent. A change in the valve position can be accompanied by a change in the stroke position.

[0025] A preferred embodiment of the invention is advantageous in which there is an effective distinction between the

[0026] A balancing valve is arranged between the fuel gas inlet and the inlet area, and parallel to the fluid valve. The balancing valve can be located upstream of the fluid valve and act in parallel with it. Before a change in the valve position, the balancing valve can be at least partially open. The balancing valve can be a pilot valve. The balancing valve can reduce the pressure differential of the fluid pressure between the inlet area and the fuel gas inlet, particularly before a change in the valve position of the fluid valve. This reduces the actuation force required to open the fluid valve against the pressure force generated by the pressure differential between the inlet area and the fuel gas inlet.

[0027] In an advantageous embodiment of the invention, the compensating valve comprises a compensating valve element that allows for a further adjustable transition opening for the fuel gas flow between the fuel gas inlet and the inlet region. This further transition opening can be arranged parallel to the transition opening with respect to the fuel gas flow between the fuel gas inlet and the inlet region.

[0028] The compensating valve element can be axially displaceable along a further axial axis or along the axial axis itself. The compensating valve element can be movable, at least section by section, with respect to the axial axis independently of the valve element.

[0029] In a specific embodiment of the invention, it is advantageous if the additional transition opening is designed as a bore in the valve element. The bore can be a central bore.

[0030] In a particular embodiment of the invention, it is advantageous if the jet pump has a housing and the mixing chamber, the jet pump nozzle, and the lifting element are at least partially contained within the housing. The compensating valve element can be at least partially contained within the housing. The valve element can be arranged at least partially within the housing.

[0031] Furthermore, within the scope of the invention, a fuel cell with the features according to claim 10 is proposed to solve at least one of the previously specified problems.

[0032] Further advantages and advantageous embodiments of the invention will become apparent from the description of the figures and the illustrations. Description of Figures

[0033] The invention is described in detail below with reference to the illustrations. These show, in detail:

[0034] Figure 1: A cross-section of a jet pump in a special embodiment of the

[0035] Invention.

[0036] Figures 2 to 7: Different positions of the jet pump from Figure 1.

[0037] Figure 1 shows a cross-section of a jet pump in a specific embodiment of the invention. The jet pump 10 for a fuel cell comprises an outlet opening 12 for supplying a fuel gas fluid to the fuel cell, a circulation inlet 14 for returning a recirculation fluid from the fuel cell after the fuel gas fluid has been processed there, and a fuel gas inlet 16 for introducing fuel gas, in particular hydrogen, into the jet pump 10. The fuel gas fluid consists of a mixture of the fuel gas, in particular hydrogen, and the recirculation fluid. The recirculation fluid can be excess hydrogen derived from the anode circuit of the fuel cell, which is preferably dehydrated or dehumidified before being supplied to the jet pump 10.Due to a superstoichiometric proportion of the fuel gas fluid supplied to the fuel cell, the return fluid entering via the circulation input 14 can be diverted away from the fuel cell as the excess portion not involved in the reaction in the fuel cell, in particular the electrochemical reaction, in order to be present at the circulation input 14.

[0038] Furthermore, the jet pump 10 comprises a housing 18 and, within the housing 18, a mixing chamber 20 connecting the circulation inlet 14 with the outlet opening 12, in particular a mixing tube and a jet pump nozzle 26 that can discharge the fuel gas from the fuel gas inlet 16 via an inlet-side inlet area 22 and a nozzle outlet opening 24 adjoining it into the mixing chamber 20. The nozzle outlet opening 24 and the jet pump nozzle 26 are arranged within the housing 18. The inlet area 22 is in particular a nozzle chamber 28. The nozzle outlet opening 24 is adjustable depending on the stroke position of a lifting element 30. The lifting element 30 is axially displaceable along an axial axis 34 by an actuator element 32. The actuator element 32 comprises a housing-mounted coil winding 36 and an armature 38 arranged axially displaceably within the coil winding 36. The lifting element 30 is axially displaceably connected to the armature 38.The actuator element 32 has an actuator housing 40 that is rigidly connected to the housing 18 and is designed to be fluid-tight with respect to the fuel gas. Alternatively, the housing 18 can be formed as a single unit with the actuator housing 40.

[0039] The lifting element 30 is, for example, a valve needle 42 which is axially displaceable along the axial axis 34 and comprises a conical closure area 44 which is axially displaceable relative to a correspondingly conically recessed receiving seat 46 and changes the nozzle outlet opening 24 as an opening between the closure area 44 and the receiving seat 46 depending on the lifting position.

[0040] A fluid valve 48 is effectively arranged between the fuel gas inlet 16 and the inlet region 22 with respect to the fuel gas flow. A transition opening 50 for the fuel gas flow is effectively adjustable between the fuel gas inlet 16 and the inlet region 22 depending on the position of the fluid valve 48. The fluid valve 48 can be a shut-off valve 52 that regulates or interrupts the fuel gas supply to the inlet region 22.

[0041] The transition opening 50 is located upstream of the nozzle outlet opening 24 with respect to the fuel gas flow. This means that the fuel gas can be guided as a fuel gas flow from the fuel gas inlet 16 via the transition opening 50 of the fluid valve 48 to the inlet area 22. The transition opening 50 can be changed depending on the valve position by a valve element 54 of the fluid valve 48, which is axially displaceable along the axial axis 34. The valve element 54 is coupled to the stroke element 30, in this case, in particular, as a single unit.

[0042] The valve element 54 comprises a valve disc 56 which, depending on the valve position, bears against a sealing area 61 of a receiving housing 62 by means of at least one sealing element 58, in particular a sealing ring 60. The receiving housing 62 also defines the inlet area 22 and forms the closure area 44. The valve position and the stroke position are interdependent, as the valve element 54 moves together with the stroke element 30.

[0043] The displacement of the valve element 54 to change the valve position, in particular to open the fluid valve 48, is effected by a drive element 64, which is fixedly connected to the armature 38 and is preferably a single piece. To change the valve position, the drive element 64 engages a contact area 66 on the valve element 54 and moves the valve element 54 axially away from the sealing area 61. Furthermore, a compensating valve 68 is arranged within the housing 18 between the fuel gas inlet 16 and the inlet area 22 and parallel to the fluid valve 48. The compensating valve 68 comprises a compensating valve element 72 that is axially displaceable along the axial axis 34 and a further transition opening 70 that is adjustable between the fuel gas inlet 16 and the inlet area 22. The further transition opening 70 is designed as a bore 74 extending along the axial axis 34, here as a central bore, in the valve element 54.The balancing valve element 72 is formed in one piece with the armature 38. The balancing valve element 72 has a further sealing element 76 which closes the balancing valve 68 when it is closed.

[0044] The compensating valve 68 can reduce the pressure difference of the fluid pressure between the inlet area 22 and the fuel gas inlet 16. This reduces the actuating force required to open the fluid valve 48, thus mitigating the pressure force generated by the pressure difference between the inlet area 22 and the fuel gas inlet 16. The drive element 64 has at least one through-hole 78 that fluidly connects the bore 74 to the fuel gas inlet 16.

[0045] A return spring 80, for example a coil spring, exerts a return force 81 on the armature 38 in the axial direction towards the lifting element 30. This causes the armature 38 to be pressed towards the lifting element 30 when the actuator element 32 is de-energized. As a result, the compensating valve element 72 closes the further transition opening 70 and seals against the contact area 66 via the further sealing element 76. Furthermore, the return spring 80 exerts the return force 81 on the valve element 54 and the lifting element 30 via the compensating valve element 72. This closes the fluid valve 48 and brings the valve needle 42 as close as possible to the closing area 44. This reduces the amount of moisture that can enter the inlet area 22 from the mixing chamber 20.

[0046] A preload spring 82 is arranged between the armature 38 and the contact area 66, thereby preloading the drive element 64 against the contact area 66 with a spring force 86. The preload spring 82 is, for example, a coil spring.

[0047] Figures 2 to 7 show different positions of the jet pump from Figure 1. In Figure 2, the actuator element 32 is de-energized, and the return spring 80 acts on the armature 38. This causes the compensating valve element 72 to close the further transition opening 70, and the valve element 54 to close the transition opening 50. The return force of the return spring 80 is greater than the spring force of the preload spring 82. The compensating valve 68 and the fluid valve 48 are therefore both closed, and the transition opening 50 and the further transition opening 70 are blocked, thus interrupting fluid transfer between the fuel gas inlet 16 and the inlet region 22. The fluid pressure in the anode circuit, and therefore also the fluid pressure in the inlet region 22, is lower than the fluid supply pressure at the fuel gas inlet 16. This pressure difference generates additional pressure forces, which close the fluid valve 48 and the compensating valve 68 in addition to the return force.

[0048] The sealing element 58 and the further sealing element 76 can be protected from excessive deformation by mechanical stops.

[0049] In Figure 3, for example, the actuator element 32 is energized with a predetermined initial current value. The actuator force on the armature 38 counteracts the restoring force and a pressure force 88 of the pressure difference at the compensating valve element 72 of the compensating valve 68. This pressure force 88 is lower than the pressure force 90 present at the valve element 54 of the fluid valve 48 due to the smaller pressure-effective area of ​​the compensating valve element 72.

[0050] The armature 38 with the compensating valve element 72 moves away from the contact area 66, and the compensating valve 68 opens. The armature movement continues until a clearance is bridged between the drive element 64 and the contact area 66. When the drive element 64 is in contact with the contact area 66, the pressure force 90 of the valve element 54 additionally opposes further movement. The movement stops because the actuator force is no longer sufficient.

[0051] Through the opening of the compensating valve 68, the fuel gas flows via the further transition opening 70 into the inlet area 22 and the pressure difference between the inlet area 22 and the fuel gas inlet 16 is reduced.

[0052] In Figure 4, the fluid pressure in the inlet area 22 is equal to the fluid pressure at the fuel gas inlet 16. The actuator element 32 continues to be energized with the first current value. Due to the small or absent pressure force on the valve element 54, the transition opening 50 opens, thereby opening the fluid valve 48.

[0053] The preload spring 82 acts on the drive element 64 against the contact area 66.

[0054] In Figure 5, the actuator element 32 is energized with a second current value that is higher than the first. This adjusts the position of the lifting element 30 in the jet pump nozzle 26 and thus the nozzle outlet opening 24. Due to the conical lifting element 30 in the correspondingly conical closure area 44, the opening cross-section of the nozzle outlet opening 24 changes with the axial movement of the lifting element 30. In Figure 6, the actuator element 32 is energized with a third current value that is higher than the second, and in Figure 7 with a fourth current value that is higher than the third. The nozzle outlet opening 24 becomes larger with increasing current value at the actuator element 32. This allows a mass flow rate and / or fluid pressure of the fuel gas fluid to be adjusted at the outlet opening.

[0055] The anchor 38 can be moved up to a mechanical stop as shown in the figure.

[0056] Reference symbol list

[0057] 10 jet pump

[0058] 12 Exit opening

[0059] 14 Circulation inlet

[0060] 16 Fuel gas inlet

[0061] 18 cases

[0062] 20 mixing chamber

[0063] 22 Entrance area

[0064] 24 Nozzle outlet opening

[0065] 26 jet pump nozzle

[0066] 28 nozzle chamber

[0067] 30 lifting elements

[0068] 32 Actuator element

[0069] 34 Axial axis

[0070] 36 coil windings

[0071] 38 anchors

[0072] 40 actuator housings

[0073] 42 Valve needle

[0074] 44 Closure area

[0075] 46 Recording seat

[0076] 48 Fluid valve

[0077] 50 Transition opening

[0078] 52 Shut-off valve

[0079] 54 Valve element

[0080] 56 valve plates

[0081] 58 Sealing element

[0082] 60 sealing ring

[0083] 61 Sealing area receiving housing

[0084] drive element

[0085] Investment area

[0086] Compensating valve, further transition opening

[0087] Compensating valve element

[0088] bore additional sealing element

[0089] Passage opening

[0090] Return spring

[0091] Restoring force

[0092] Preload spring

[0093] Spring force

[0094] Pressure

[0095] Pressure

Claims

Patent claims 1. Jet pump (10) for a fuel cell operable with fuel gas, comprising an outlet opening (12) for supplying a fuel gas fluid containing the fuel gas to the fuel cell, a circulation inlet (14) for returning a return fluid existing after the processing of the fuel gas fluid in the fuel cell from the fuel cell, and a fuel gas inlet (16) connectable to a fuel gas supply for introducing the fuel gas, a mixing chamber (20) connecting the circulation inlet (14) with the outlet opening (12), a jet pump nozzle (26) that can discharge the fuel gas from the fuel gas inlet (16) via an inlet-side inlet area (22) and a nozzle outlet opening (24) adjoining it into the mixing chamber (20), characterized in that,that the nozzle outlet opening (24) is adjustable depending on a stroke position of a stroke element (30) and a fluid valve (48) is effectively arranged between the fuel gas inlet (16) and the inlet area (22) with respect to a fuel gas flow.

2. Jet pump (10) according to claim 1, characterized in that a transition opening (50) of the fuel gas flow between the fuel gas inlet (16) and the inlet area (22) is adjustable depending on a valve position of the fluid valve (48).

3. Jet pump (10) according to claim 2, characterized in that the transition opening (50) is located upstream of the nozzle outlet opening (24) with respect to the fuel gas flow.

4. Jet pump (10) according to claim 2 or 3, characterized in that the fluid valve (48) has at least one valve element (54) which is coupled to the lifting element (30) and which can change the transition opening (50) depending on the valve position.

5. Jet pump (10) according to one of claims 2 to 4, characterized in that the valve position and the stroke position are dependent on each other.

6. Jet pump (10) according to one of the preceding claims, characterized in that a balancing valve (68) is arranged effectively between the fuel gas inlet (16) and the inlet area (22) and parallel to the fluid valve (48).

7. Jet pump (10) according to claim 6, characterized in that the compensating valve (68) has a further adjustable compensating valve element (72) for the transition opening (70) of the fuel gas flow between the fuel gas inlet (16) and the inlet area (22).

8. Jet pump (10) according to claim 7, characterized in that the further transition opening (70) is designed as a bore (74) in the valve element (54).

9. Jet pump (10) according to one of the preceding claims, characterized in that the jet pump (10) has a housing (18) and the mixing chamber (20), the jet pump nozzle (26) and the lifting element (30) are at least partially contained within the housing (18).

10. Fuel cell comprising at least one anode, at least one cathode and at least one membrane, wherein the at least one anode is arranged in an anode circuit and a jet pump (10) according to one of the preceding claims, wherein the outlet opening (12) is connected to the anode circuit on the inlet side and the circulation inlet (14) is connected to the anode circuit on the outlet side.

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