阅读说明：本技术 用于燃料电池系统的、用于输送和/或控制气态介质的输送总成 (Delivery assembly for delivering and/or controlling a gaseous medium for a fuel cell system ) 是由 A·格林贝格尔 A·里希特 H-C·马盖尔 于 2019-08-06 设计创作，主要内容包括：本发明涉及一种用于燃料电池系统(31)的输送总成(1),其用于输送和/或再循环气态介质、尤其是氢气,所述输送总成具有被处在压力下的气态介质的推进射流驱动的喷射泵(4)和配量阀(6),所述配量阀具有喷嘴(12),其中,所述输送总成(1)实施为组合式阀-喷射泵组件(2),其中,借助于所述配量阀(6)给所述喷射泵(4)供应气态介质,其中,所述喷射泵(4)具有基体(8),其中,所述喷射泵(4)与燃料电池(29)的阳极输入端(3)连接。根据本发明,在此,沿流动方向VII从所述喷射泵(4)流向所述燃料电池(29)的阳极输入端(3)的气态介质的转向和/或方向变化仅在转向区域(22)中进行,其中,所述喷射泵(4)具有与所述基体(8)连接的单独的封闭盖件(5),并且其中,所述转向区域(22)和/或用于所述气态介质的转向区域(22)的转向以及引导几何形状仅构造在封闭盖件(5)这个构件中。(The invention relates to a delivery assembly (1) for a fuel cell system (31) for delivering and/or recirculating a gaseous medium, in particular hydrogen, having an injection pump (4) which is driven by a propellant jet of the gaseous medium under pressure and having a metering valve (6) which has a nozzle (12), wherein the delivery assembly (1) is designed as a combined valve-injection pump assembly (2), wherein the injection pump (4) is supplied with the gaseous medium by means of the metering valve (6), wherein the injection pump (4) has a base body (8), wherein the injection pump (4) is connected to an anode input (3) of a fuel cell (29). According to the invention, the diversion and/or the change in direction of the gaseous medium flowing in the flow direction VII from the ejector pump (4) to the anode inlet (3) of the fuel cell (29) takes place exclusively in the diversion region (22), wherein the ejector pump (4) has a separate closing cover (5) connected to the base body (8), and wherein the diversion and the guide geometry of the diversion region (22) and/or of the diversion region (22) for the gaseous medium are formed exclusively in the component of the closing cover (5).)

1. A delivery assembly (1) for a fuel cell system (31) for delivering and/or recirculating a gaseous medium, in particular hydrogen, having a jet pump (4) which is driven by a propellant jet of the gaseous medium under pressure and having a metering valve (6) with a nozzle (12), wherein the delivery assembly (1) is embodied as a combined valve-jet pump assembly (2), wherein the jet pump (4) is supplied with the gaseous medium by means of the metering valve (6), wherein the jet pump (4) has a base body (8), wherein the jet pump (4) is connected to an anode input (3) of a fuel cell (29), characterized in that the diversion and/or change in direction of the gaseous medium flowing in a flow direction VII from the jet pump (4) to the anode input (3) of the fuel cell (29) is effected exclusively in a diversion region (22) ) Wherein the injection pump (4) has a separate closure cover (5) connected to the base body (8), and wherein the deflection region (22) and/or the deflection geometry of the deflection region (22) for the gaseous medium is formed exclusively in the component closure cover (5).

2. The delivery assembly (1) according to claim 1, wherein the closure cap (5) has a deflection stub (15) having a preferably cylindrical outer shape, wherein the deflection stub (15) of the closure cap (5) extends in the installed state in the direction of a longitudinal axis (30) in the base body (8), and wherein the deflection stub (15) preferably has a recess (17) in its inner shape, wherein the recess (17) serves in particular for flow guidance of the gaseous medium.

3. The delivery assembly (1) according to claim 1 or 2, wherein there is a connection (26) between the closing cover (5) and the anode input (3) of the fuel cell (29).

4. The delivery assembly (1) according to claim 2 or 3, characterized in that the gap (17) of the deflection nipple (15) at least indirectly fluidically connects a diffusion region (20) with the connection piece (26) of the jet pump (4) to one another.

5. The delivery assembly (1) according to claim 4, characterized in that the cutout (17) of the deflection nozzle (15) is shaped in such a way that it opens out into the flow cross section of the diffusion region (20) and into the flow cross section of the connecting piece (26) in such a way that a gaseous medium can flow through the deflection nozzle (15) in the flow direction VII.

6. The delivery assembly (1) according to claims 2 to 5, characterized in that the deflection and/or the change in direction of the gaseous medium takes place in the deflection region (22) almost at right angles by means of the deflection nipple (15).

7. The delivery assembly (1) according to one of claims 2 to 6, characterised in that the deflection stub (15) has an at least approximately spherical inner surface (19) in the region of the recess (17) at least in sections in the built-in flow cross section of the deflection stub.

8. The delivery assembly (1) according to one of the preceding claims, wherein the closure cap (5) is connected to the base body (8) by means of a detachable connection, in particular a screw connection, so that the closure cap (5) can be detached from the base body (8).

9. The delivery assembly (1) according to any one of the preceding claims, wherein the component base (8) and/or the closing cover (5) are made of a material or an alloy having a low specific heat capacity.

10. Delivery assembly (1) according to one of claims 2 to 9, characterized in that the component base body (8) of the jet pump (4) and/or the closing cover (5) are made of a metallic material or a metallic alloy.

11. Delivery assembly (1) according to any one of the preceding claims, wherein the combined valve-jet pump assembly (2) has a heating element (11).

12. The delivery assembly (1) according to claim 1, characterized in that the end section of the diffusion region (20) of the jet pump (4), the deflection region (22), the jet pump (4) and the connection (26) of the anode input (3) have at least approximately the same cross section extending orthogonally with respect to the flow direction VII.

13. The delivery assembly (1) according to claim 1, wherein the dosing valve (6) is embodied as a proportional valve (6).

14. The delivery assembly (1) according to claim 1, characterized in that the nozzle (12) and the mixing tube (18) of the jet pump (4) are embodied rotationally symmetrically, wherein the nozzle (12) extends coaxially with respect to the mixing tube (18) of the jet pump (4).

15. A fuel cell system (31) having a delivery assembly (1) according to any one of the preceding claims.

Technical Field

The invention relates to a delivery assembly for a fuel cell system for delivering and/or controlling a gaseous medium, in particular hydrogen, which is provided, in particular, for use in a vehicle having a fuel cell drive.

Background

In the field of vehicles, gaseous fuels will play an increasingly important role in the future, in addition to liquid fuels. Especially in a vehicle having a fuel cell drive apparatus, it is necessary to control the flow of hydrogen gas. In this case, the gas flow is no longer controlled discontinuously, as is the case with the injection of liquid fuel, but rather gas is taken from at least one tank, in particular a high-pressure tank, and is conducted to the delivery assembly via the inflow line of the medium-pressure line system. The delivery assembly directs the gas to the fuel cell via a connecting line of the low-pressure line system.

DE 102014105995 a1 discloses a delivery assembly for a fuel cell system for delivering a gaseous medium, in particular hydrogen, having a jet pump driven by a propellant jet of the gaseous medium under pressure and a metering valve. The delivery assembly can be embodied as a combined valve-jet pump assembly and can have a component first inlet, a suction region, a mixing tube and a diffuser region, and the metering valve has a second inlet and a nozzle. In this case, the medium, in particular the propellant medium, can be discharged through the nozzle by means of the conveying assembly, and the propellant medium is then mixed with the recirculating medium. The flow of propellant medium can be controlled by means of a metering valve.

The delivery assembly known from DE 102014105995 a1 may have certain disadvantages.

When the delivery unit is mounted on the anode inlet of the fuel cell, the medium to be delivered must be diverted downstream of the delivery unit, in particular after the flow-through diffusion region, before it can flow into the anode inlet. When the medium to be conveyed is diverted, in particular is diverted, flow losses and/or pressure losses can occur between the conveying assembly, in particular the combined valve jet pump assembly, and the anode input as a result of the diversion in the flow line system, which is embodied, for example, as a pipe system. In this case, the efficiency of the overall fuel cell system, in particular of the valve-jet pump assembly, is reduced. In addition, the connection of the feed assembly to the anode inlet via a line is disadvantageous in this respect, since sealing problems can occur over the entire service life of the fuel cell system, in particular if the temperature fluctuates strongly, in the case of a line, in particular if the line is welded and/or soldered. Thereby, the probability of failure of the entire fuel cell system is increased.

Disclosure of Invention

According to the invention, a delivery assembly for a fuel cell system is proposed for delivering and/or recirculating a gaseous medium, in particular hydrogen, wherein hydrogen is referred to as H in the following₂。

In accordance with claim 1, the diversion and/or the change in direction of the flow direction VII of the gaseous medium flowing from the jet pump to the anode input of the fuel cell takes place exclusively in the diversion region, wherein the jet pump has a separate closing cover connected to the base body, wherein the diversion and guide geometry for the gaseous medium of the diversion region and/or the diversion region is formed exclusively in the component closing cover. In this way, the steering and guide geometry can be integrated into the injection pump and in the flow line system and/or the line system in the delivery assembly (in particularDiffusion region) and the anode input of the fuel cell without further diversion of the medium to be conveyed. In addition, the flow losses and/or pressure losses due to the steering can be kept as small as possible. For this purpose, the radii in the deflection region and/or the deflection geometry of the deflection region for the gaseous medium are implemented such that the medium to be conveyed, in particular H₂As little friction as possible occurs with the surface of the flow geometry of the turning area. As a result, pressure losses and friction losses can be reduced on the basis of the flow diversion and/or the change in flow direction of the gaseous medium through the bend, as a result of which the efficiency of the delivery assembly and/or the efficiency of the valve-jet pump assembly and/or the efficiency of the overall fuel cell system can be improved. Furthermore, by integrating the deflecting region into the jet pump, in particular into the closing cover, the advantage is achieved that there is as little space as possible between the output of the valve-jet pump assembly and the anode input of the fuel cell, and therefore a shorter flow line is formed. Thereby, the flow loss and/or the pressure loss can be kept low, whereby the efficiency of the fuel cell system can be further improved. In addition, the configuration of the delivery unit according to the invention enables the advantage that the risk of leakage of the fuel cell system is reduced, since the line system, in particular between the injection pump and the fuel cell, is either not required at all or is only required in a shortened form. Furthermore, the integration of the deflecting region into the jet pump is advantageous in that no additional installation space, for example in the form of additional lines, is required. The advantage of a compact design of the conveying assembly can thus be achieved.

Advantageous embodiments of the conveying assembly described in claim 1 can be achieved by the measures specified in the dependent claims. The dependent claims relate to preferred embodiments of the invention.

According to an advantageous embodiment of the delivery unit, the closing cap has a deflection stub having a preferably cylindrical outer shape, wherein the deflection stub of the closing cap extends in the installed state in the direction of the longitudinal axis in the base body, and wherein the deflection stub preferably has a recess in its inner shape, wherein the recess is used in particular for guiding the flow of the gaseous medium. In addition, the conveying assembly is designed in such a way that in the deflection region, a deflection and/or a change in direction of the gaseous medium can be achieved almost at right angles by means of the deflection connection. In this way, the gaseous medium can be diverted in such a way that as little friction losses as possible occur, as a result of which the efficiency of the jet pump and/or the efficiency of the delivery assembly and/or the efficiency of the overall fuel cell system can be improved. Furthermore, no additional lines are required between the ejector pump and the anode input, as a result of which the number of additional components for achieving a diversion of the gaseous medium, in particular a flow diversion, is reduced. In addition, the complexity of the fuel cell system can thus be reduced, since fewer components are required. Thereby, material costs, manufacturing costs and assembly costs can be reduced. In addition, the mass of the structural material of the fuel cell system can be reduced and/or the thermal capacity can be reduced, as a result of which a more rapid heating of the delivery assembly and thus a more rapid elimination of the constituent ice bridges is possible. Thus, damage to the components of the transport assembly and other components of the fuel cell system, in particular the membrane stack, is prevented, which is caused by ice particles transported together in the medium to be transported, which ice particles may fall off the surface during cold start if the heating of the transport assembly is too slow.

According to an advantageous embodiment of the delivery assembly, a connection is provided between the closing cover and the anode inlet of the fuel cell. In this way, the advantage is achieved that the flow connection between the injection pump, in particular the closing cover, and the anode inlet can be made as short as possible, at least virtually without flow losses. Therefore, since the friction loss is reduced, the efficiency of the delivery assembly and thus the efficiency of the entire fuel cell system can be improved. In addition, since the connection piece is integrated as part of the base body of the injection pump, the transition in the flow region between these parts of the injection pump of the delivery assembly can be implemented in a flow-optimized manner. In this way, the flow resistance of the conveying assembly can be reduced, in particular in the region of the components diffusion region, deflection region and connecting element. By means of the configuration according to the invention, the flow speed of the medium to be conveyed can be kept at a high level in the inner flow cross section and virtually no friction losses and/or flow losses occur. The efficiency of the delivery assembly and thus of the entire fuel cell system can be increased thereby. Furthermore, the configuration of the delivery assembly according to the invention enables the advantage that the delivery assembly and/or the combined valve and injector pump assembly can be connected to the end plate of the fuel cell in a space-saving and compact design, as a result of which the space requirement and installation space of the fuel cell system in the vehicle can be reduced.

According to a particularly advantageous embodiment, the recess of the deflection stub at least indirectly fluidically connects the diffuser region to the connection piece of the injection pump. In addition, the recess of the deflection stub is shaped in such a way that it opens out into the flow cross section of the diffuser region and into the flow cross section of the connection piece, so that the gaseous medium can flow through the deflection stub in the flow direction VII. Furthermore, the deflecting stub has an at least approximately spherical inner surface in the region of the recess in the built-in flow cross section of the deflecting stub. In this way, the advantage is achieved that the transitions in the flow cross-sections of the diffuser region, the deflection region and the connecting piece of the conveying assembly between these parts are implemented in a manner which is as smooth and as flow-optimized as possible. In this case, in particular, in the region of these transitions, any vortex or flow separation which might lead to the medium to be conveyed is avoided as much as possibleThe gap or edge of (a). A swirl or flow deceleration of the medium to be conveyed can be caused by such gaps or edges in the flow cross section. Thus, by means of the configuration of the conveying assembly according to the invention, the internal flow resistance in the flow cross section can be reduced, thereby increasing the efficiency of the conveying assembly. In addition, the configuration according to the invention of the deflection connection and/or the configuration according to the invention of the cutout of the deflection connection enables a cost-effective production of the deflection region in the delivery unit, since the deflection flow geometry only has to be introduced into the component deflection connection. In addition, the closure cap with the steering nipple can be mounted onThe base body of the jet pump is previously accessible for the production method, in particular the chip-removing production method, and only relatively small components have to be machined and clamped on the machine tool. Therefore, manufacturing costs, machining costs, and component costs can be reduced. In addition, an increase in the diffusion tightness can be achieved in this way, since the components forming the flow cross section between the mixing tube of the jet pump and the anode input of the fuel cell have as few joints as possible, wherein the joints between the components are susceptible to leakage in the event of a faulty connection process. The probability of failure of the delivery assembly due to leakage of the flow cross section of the fuel cell system can thus be reduced.

According to an advantageous embodiment, the closure cap of the delivery unit is connected to the base body by means of a detachable connection, in particular a screw connection. In this case, the closing cover can be detached from the base body, in particular when the screw is loosened. In this way, the advantage is achieved that, in the event of damage to the flow cross section in the diverting region of the conveying assembly, for example due to ice particles in the event of low ambient temperatures and/or cold start-up procedures, damage can be eliminated cost-effectively and quickly by replacing the closure cap by loosening the screw. In the case of maintenance work and/or repair work, the closure cap can also be detached from the base body quickly and without destructive machining by means of screwing, as a result of which the ease of maintenance is increased and the maintenance and/or operating costs can be reduced. Furthermore, it is possible to prevent the entire delivery unit from having to be replaced when the deflection region and/or the adjacent flow region is damaged, but instead the closure cover is replaced.

According to a particularly advantageous embodiment of the delivery assembly, the component base and/or the closing cover are made of a material or an alloy having a low specific heat capacity. In addition, the component base body and/or the closure cap of the injection pump are made of a metallic material or a metallic alloy. Furthermore, the combined valve-jet pump assembly can have a heating element. Since water in the fuel cell region can diffuse from the cathode region through the membrane into the anode region during operation of the fuel cell system, this water can flow together in the flow region of the anode side and accumulate at defined points. When the vehicle is switched off and the fuel cell system is therefore switched off, this water can freeze at low temperatures, in particular below 0 ℃, and for long periods of time when the vehicle is parked, and forms what is known as an ice bridge. These ice bridges may damage components of the fuel cell system and/or components of the delivery assembly and/or components of the jet pump. The improved thermal conductivity of the materials used can therefore lead to a more rapid heating of the component base and/or of the closing cover and thus of the entire delivery assembly. Another measure for achieving a rapid heating of the transport assembly according to the invention is the use of heating elements. In this way, in the context of a cold start procedure, the heating element can be supplied with energy, in particular electrical energy, before the transport assembly and/or the entire fuel cell system is put into operation at low temperatures, wherein the heating element converts this energy into heat and/or thermal energy. This process is advantageously assisted by the low specific heat capacity of the other components of the conveying assembly, by means of which thermal energy can be rapidly advanced into the entire conveying assembly and existing ice bridges can be eliminated. By heating the parts and the transport assembly more quickly, existing ice bridges can be eliminated more quickly, in particular by melting due to heat input. Furthermore, during a cold start, shortly after switching on the heating element, the heating energy can be pushed to the nozzle and the existing ice bridge in the region of the nozzle and in the region of the actuating mechanism of the metering valve is heated and thus eliminated. This reduces the probability of failure due to damage to components of the transport assembly. In this way, the cold start capability of the delivery assembly and thus of the entire fuel cell system can be improved, as a result of which the ice bridge can be thawed and eliminated more quickly. Furthermore, less energy has to be introduced into the conveying assembly, in particular less electrical and/or thermal energy has to be introduced into the conveying assembly by the heating element used. In this way, the operating costs of the delivery assembly and of the entire fuel cell system can be reduced, in particular in the case of frequent cold start processes due to low ambient temperatures and/or long vehicle downtimes. In addition, by using the material according to the invention, a high resistance to the medium to be transported by the transport assembly and other constituents, such as chemicals, from the surroundings of the transport assembly can also be achieved. This in turn increases the service life of the conveying assembly and enables a reduction in the probability of failure due to material damage of the housing.

According to an advantageous embodiment of the delivery unit, the end section of the diffuser region of the jet pump, the deflecting region, the connection piece of the jet pump and the anode inlet have at least approximately the same cross section extending orthogonally to the flow direction VII. In this way, the volume flow of the medium in the delivery assembly can be kept constant and the flow velocity of the medium can thus be kept constant, whereby energy losses due to acceleration or deceleration of the medium can be reduced. Furthermore, the frictional losses of the medium and the wall of the flow region of the conveying assembly, which occur when the flow cross section changes, are also reduced. The configuration of the conveying assembly according to the invention thus makes it possible to reduce the internal flow resistance in the flow cross section, thereby increasing the efficiency of the conveying assembly. In addition, the advantage is achieved that, when the gaseous medium is deflected in the deflection region, friction losses and/or pressure losses and/or flow losses are kept low by this shaping of the cross section of the parts of the conveying assembly. This is possible because, in addition to the diversion of the medium, no other structural embodiments are present on the transport assembly which cause the above-mentioned losses, for example a changing cross section upstream of the diversion region, in the diversion region and/or downstream of the diversion region. Such an embodiment may lead to a flow backlog of the medium, wherein such a flow backlog causes additional friction losses and/or pressure losses and/or flow losses, whereby the efficiency of the entire conveying assembly is further reduced.

According to a particularly advantageous embodiment, the metering valve is embodied as a proportional valve. In this way, the advantages of a reduced weight of the delivery unit and a compact design can be achieved, since the metering valve embodied as a proportional valve requires less installation space and has a lower dead weight. Furthermore, the metering valve can be actuated more precisely and more rapidly by means of the proportional valve than in the alternative technical embodiment of the metering valve. The advantage is thereby achieved that the amount and the timing of the propellant medium supplied by means of the metering valve to the suction region and/or the mixing pipe of the ejector pump can be metered more precisely, as a result of which the efficiency of the ejector pump and thus of the entire delivery assembly can be improved.

According to one advantageous embodiment, the nozzle and the mixing tube of the jet pump are rotationally symmetrical, the nozzle extending coaxially with respect to the mixing tube of the jet pump. In this way, the advantage is achieved that an improved mixing of the propellant medium with the recirculated material can be achieved in the ejector pump, in particular in the suction region and/or in the mixing tube. In addition, an improved momentum transfer from the propellant medium from the metering valve to the recirculation can be achieved in the suction region and in the mixing tube region. The efficiency of the conveying assembly can thus be increased and the operating costs of the conveying assembly can be reduced if the conveying capacity is equal.

Drawings

The invention is explained in more detail below with reference to the drawings.

The figures show:

figure 1 is a schematic cross-sectional view of a delivery assembly having a combination valve-jet pump assembly,

figure 2 is a perspective view of an enclosing cover according to the invention of a delivery assembly,

fig. 3 is a partially schematic cross-sectional view of a fuel cell system having a valve-jet pump unit and a fuel cell.

Detailed Description

The illustration according to fig. 1 shows a schematic sectional illustration of a delivery assembly 1, wherein the delivery assembly 1 has a combined valve and injection pump assembly 2. The combined valve and injection pump assembly 2 has a metering valve 6 and an injection pump 4, wherein the metering valve 6 is connected to the injection pump 4, in particular to a base body 8 of the injection pump 4, for example by screwing.

The injection pump 4 has a component base 8 and a closure cap 5. In this case, the ejector pump 4 has a first inlet 28, a second inlet 36a, a suction region 7, a mixing tube 18, a diffusion region 20 and a deflection region 22 and/or a connection piece 26 in the region of one or both components. The dosing valve 6 has a second inlet 36b, a first sealing element 14, a second sealing element 16 and a nozzle 12. In this case, the metering valve 6 is pushed in particular in the direction of the longitudinal axis 30 into the jet pump 6, in particular into an opening in the base body 8 of the jet pump 6. In an exemplary embodiment of the delivery unit 1, the closure cap 5 can be pushed into the base body 8 in the direction of the longitudinal axis 30.

Fig. 1 also shows that the combined valve-jet pump assembly 2 is traversed by the medium to be conveyed in the flow direction VII. The majority of the flow-through region of the valve-jet pump assembly 2 is at least approximately tubular and is used for conveying and/or guiding a gaseous medium, in particular H, in the conveying assembly 1₂. The gaseous medium flows through a central flow region 21 inside the main body 8 in the flow direction VII parallel to the longitudinal axis 30, wherein the central flow region 21 begins in the region of the mouth of the nozzle 12 in the suction region 7 and extends through the mixing tube 18, the diffusion region 20 and into the deflection region 22. Here, on the one hand, the valve-jet pump assembly 2 is supplied with recirculation via the first inlet 28, wherein the recirculation is in particular unconsumed H from the anode region of the fuel cell 29, in particular from the stack₂Wherein the recycle can also have water and nitrogen. The recirculated material flows in the first flow path V into the valve-jet pump assembly 2. In another aspect, the gaseous propellant medium, especially H₂Through the second inlet 36, on the second flow path VI, the propellant medium can flow out of the valve-jet pump assembly 2 into the recess of the valve-jet pump assembly 2 and/or into the base body 8 and/or into the metering valve 6, wherein the propellant medium is able to come from the tank 34 and is at a high pressure. In this case, the second inlet 36a, b extends through the component base body 8 and/or the metering valve 6. By means of the actuating mechanism and the completely closable valve element, the propellant medium is discharged from the metering valve 6, in particular intermittently, through the nozzle 12 into the suction region 7 and/or the mixing tube 18. H flowing through the nozzle 12 and acting as a propelling medium₂A pressure difference with the recirculating medium flowing from the first inlet 28 into the conveying assembly 1, wherein the propellant medium has in particular a relatively high pressure of at least 10 bar.In order to produce the so-called jet pump effect, the recirculating medium with low pressure and low mass flow is fed into the central flow region of the conveying assembly 1, for example by using a side channel compressor 10 (not shown in fig. 1) connected upstream of the conveying assembly 1. In this case, the propellant medium with the pressure difference and the high speed, which can be in particular close to sonic speed, flows through the nozzle 12 into the central flow region 21 of the suction region 7 and/or of the mixing tube 18. The nozzle 12 has an inner opening in the form of a flow cross section through which the gaseous medium can flow, in particular from the metering valve 6, and into the suction region 7 and/or the mixing tube 18. Here, the propellant medium encounters the recirculating medium already in the central flow region of the suction region 7 and/or of the mixing tube 18. Due to the high velocity difference and/or the high pressure difference between the propelling medium and the recirculating medium, internal friction and turbulence are generated between these media. Here, shear stresses are generated in the boundary layer between the fast propelling medium and the significantly slower recirculating medium. This stress causes momentum transfer, wherein the recirculating medium is accelerated and dragged. Mixing occurs according to the principle of conservation of momentum. In this case, the recirculating medium is accelerated in the flow direction VII, a pressure drop occurs for the recirculating medium, as a result of which a suction effect begins and thus additional recirculating medium is fed in from the region of the first inlet 28. This effect can be referred to as a jet pump effect. By actuating the supply of the dosing (Zu-Dosierung) propellant medium by means of the dosing valve 6, the delivery rate of the recirculated medium can be adjusted and adapted to the respective requirements of the overall fuel cell system 31 depending on the operating state and operating requirements. In an exemplary operating state of the delivery assembly 1, in which the metering valve 6 is in the closed state, a supplementary flow of the propellant medium from the second inlet 36 into the central flow region of the ejector pump 4 can be prevented, so that the propellant medium cannot flow further in the flow direction VII into the suction region 7 and/or the mixing tube 18 relative to the recirculating medium and the ejector pump effect is therefore interrupted.

After passing through the mixing tube 18, the mixed and to-be-conveyed medium flows in the flow direction VII into the diffusion region 20, which medium comprises in particular the recirculating medium and the propellant medium, wherein a reduction in the flow velocity can occur in the diffusion region 20. From there, the medium flows in the flow direction VII from the diffusion region 20 into the deflection region 22, wherein it undergoes a corresponding deflection in the deflection region and from there further flows via the connection piece 26 into the anode input 3 of the fuel cell 29.

The closure cap 5 has a deflection nipple 15 with a recess 17, wherein the deflection nipple 15 projects into the opening of the base body 8 and forms a flow area and/or a flow cross section of the injection pump 4 in a deflection area 22 by means of the profiling 17. In this case, the diffuser region 20 and the connection piece 26 of the injection pump 4 are at least indirectly in fluid communication with one another via the recess 17 of the deflection stub 15. In addition, the recess 17 of the deflection nozzle 15 is shaped in such a way that it opens out into the flow cross section of the diffuser region 20 and into the flow cross section of the connecting piece 26, so that the gaseous medium can flow through the deflection nozzle 15 in the flow direction VII. In this way, the deflection and/or the change in direction of the gaseous medium can be achieved almost at right angles in the deflection region 22 by means of the deflection stub 15. The closure cap 5 is connected to the base body 8 by means of a detachable connection, in particular screwed, so that the closure cap 5 can be detached from the base body 8. Furthermore, the closure cap 5 can be made of a different material than the base body 8, wherein the two materials in particular have different coefficients of thermal expansion. In an exemplary embodiment, the closing cover 5 can also be cooled before being fitted and pushed into the base body 8 and fixed by screwing in such a way that the diameter, in particular the diameter of the steering stub 15, is reduced. In this way, a simplified assembly is achieved due to the reduced diameter of the closure cover 5, in particular of the steering nipple 15. In a further advantageous manner, the diameter expands when the ambient temperature is reached in such a way that an improved sealing and/or encapsulation between the component closure cover 5 and the base body 8 is achieved. Furthermore, a third sealing element can be located between the closure lid 5 and the base body 8.

The task of the first sealing element 14 and/or the second sealing element 16 shown in fig. 1 is to encapsulate the propellant medium under high pressure flowing into the metering valve 6 via the second flow path VI. The corresponding sealing elements are embodied here as sealing elements 14, 16, in particular as O-rings, which surround the metering valve 6. In this case, at least one sealing element 14, 16 prevents the propellant medium from possibly escaping in the region of the second inlet 36 and/or the medium to be conveyed from escaping from the interior of the base body 8 and/or the metering valve 6 and possibly out of the region outside the valve-jet pump assembly 2, in that at least one sealing element 14, 16 achieves a sealing effect between the metering valve 6 and the base body 8. In the region outside the valve-jet pump assembly 2, the medium to be conveyed can react adversely with the surrounding oxygen and damage the conveying assembly 1 and/or the entire vehicle.

In addition, the ejector pump 4 in fig. 1 has technical features which additionally improve the ejector pump effect and the delivery efficiency and/or further improve the cold start process and/or the production and assembly costs. In this case, the partial diffusion region 20 extends conically in the region of its inner flow cross section, in particular conically expanding in the flow direction VII. By this shaping of the partial diffusion region 20, a favorable effect can be produced: the kinetic energy is converted into pressure energy, as a result of which the possible conveying volume of the conveying assembly 1 can be further increased, as a result of which the medium to be conveyed, in particular H, can be conveyed₂More is supplied to the fuel cell 29, whereby the efficiency of the entire fuel cell system 31 can be improved.

According to the invention, the metering valve 6 can be embodied as a proportional valve 6, in order to be able to achieve an improved metering function and to be able to more precisely meter the propellant medium into the suction region 7 and/or the mixing tube 18. In order to further improve the flow geometry and the efficiency of the delivery assembly 1, the nozzle 12 and the mixing tube 18 are embodied rotationally symmetrically, wherein the nozzle 12 extends coaxially to the mixing tube 18 of the jet pump 4.

Fig. 2 shows a perspective view of a closure cap 5 according to the invention, which has a steering nipple 15. The closing cap 5 has a deflection stub 15 with a preferably cylindrical outer shape, wherein the deflection stub 15 of the closing cap 5 extends in the installed state in the direction of the longitudinal axis 30 in the base body 8 (as shown in fig. 1), and wherein the deflection stub 15 preferably has a recess 17 in its inner shape, wherein the recess 17 serves in particular for guiding the flow of the gaseous medium. Fig. 2 also shows that, in the region of the recess 17, the deflecting nipple 15 has an at least approximately spherical inner surface 19 in terms of its inner flow cross section. Due to this at least approximately spherical inner surface 19, less friction losses occur when the medium to be conveyed is diverted in the diverting region 22 of the jet pump 4, since in this way the friction between the medium to be conveyed and the inner surface 19 and/or the flow geometry of the closing cover 5 is reduced. In this way, friction losses and/or pressure losses and/or flow losses in this region are kept low, whereby the efficiency of the conveying assembly 1 is improved. The inner surface 19 also has as little surface roughness as possible, which leads to a further reduction in flow losses.

As shown in fig. 2, the deflection nozzle 15 has, in the region of the inner surface 19, the contour of the spherical inner surface 19 leading to the further flow cross-sections of the diffuser region 20 and of the connecting piece 26 in such a way that the transition from the spherical contour of the inner surface 19 to the further flow cross-sections is implemented in a flow-optimized manner. As a result, the flow resistance of the delivery unit 1 can be reduced, in particular in the region of the partial diffusion region 20, the deflection region 22 and the connecting piece 26. By means of the configuration according to the invention, the flow speed of the medium to be conveyed can be kept constant in the inner flow cross section and virtually no friction losses and/or flow losses occur. As a result, the efficiency of the valve-jet pump assembly 2 and of the delivery assembly 1 and thus of the entire fuel cell system 31 can be increased. The inner flow cross section is designed smooth and flow-optimized, so that as little flow resistance as possible is produced as a result of the surfaces located in the inner flow cross section that are joined together in this region. The flow optimization of the surfaces can be further improved by mechanical post-treatment of the surfaces of the portions lying in the inner flow cross section, for example by deburring, grinding, milling or polishing of these surfaces, which is only possible when using a material-locking connection method, in particular when the base body 8 and/or the closure cover 5 are metallic parts.

The illustration according to fig. 3 shows a partial schematic cross-sectional view of a fuel cell system 31 with a valve-jet pump assembly 2, a fuel cell 29, as well as an optional component water separator 24 and a side channel compressor 10. The combined valve and injection pump assembly 2 is mounted and/or mounted on the fuel cell 29, the valve and injection pump assembly 2 being mounted in particular on the end plate 13 of the fuel cell 29. In fig. 3, it is shown that the gaseous medium flowing through the ejector pump 4 in the flow direction VII and parallel to the longitudinal axis 30 must undergo a deflection and therefore a change in flow direction before entering the anode inlet 3 of the fuel cell 29.

In fig. 3, it is shown that the diversion and/or the change in direction of the gaseous medium flowing in the flow direction VII from the jet pump 4 to the anode inlet 3 of the fuel cell 29 takes place exclusively in the diversion region 22, wherein the jet pump 4 has a separate closing cover 5 connected to the base body 8, and wherein the diversion and guide geometry for the gaseous medium of the diversion region 22 and/or the diversion region 22 is formed exclusively in this component of the closing cover 5.

In fig. 3, it is shown that, on the one hand, unconsumed gaseous medium flows from the anode outlet 9 of the fuel cell 29, in particular the stack, in the flow direction VII through the end plate 13 via the optional water separator 24 and the optional side channel compressor 10 into the first inlet 28 of the valve-jet pump assembly 2. From there, the gaseous medium flows into the suction region 7 and partially into the mixing tube 18 of the ejector pump 4. The water separator 24 has the task of separating the gaseous medium, in particular H, which is generated during operation of the fuel cell 29 and which is present₂The water that flows back into the valve-jet pump assembly 2 through the anode output 9 together is conducted out of the system. Thus, water which can be present in the gaseous and/or liquid state cannot be pushed into the recirculation blower 10 and/or the ejector pump 4 and/or the metering valve 6, since it is already separated from the gaseous medium directly by the water separator 24 and is removed from the fuel cell system 31 by the conveying device. This prevents corrosion of the components of the transport assembly 1 andand/or damage to components of the fuel cell system 31, in particular movable parts of said components, thereby increasing the service life of all the components through which the flow is conducted. In addition, in the fuel cell system 31, the water is separated early and quickly, and the efficiency of the conveyance assembly 1 can be improved. This is because the water does not have to pass through further components of the delivery assembly 1 with the gaseous medium, in particular H₂Are conveyed together, which conveying reduces the efficiency, since less gaseous medium is conveyed in the conveying assembly 1 for conveying the portion of water and since the water has a greater mass. Thus, the following advantages can be achieved by using and arranging the water separator 24 accordingly, the efficiency of the transport assembly 1 can be improved. By means of the diversion of the medium in the diversion region 22 via the diversion connection 15, the medium does not have to undergo further diversion in the subsequent process and can flow into the anode inlet 3 after passing through the outlet bend 22 with little or no further diversion and frictional losses. In an exemplary embodiment, the valve-jet pump assembly 2 and/or the delivery assembly 1 are preferably arranged in parallel with the end plate 13 of the fuel cell 29. This applies in particular when the fuel cell system 31 may have a compact size due to structural limitations on or in the vehicle. The anode gas stream flowing out of the ejector pump 4 must therefore be deflected almost at right angles or at least at an acute angle in order to reach the anode input 3 of the fuel cell 29. The flow region of the delivery assembly 1 is designed such that the cross section of the end section of the diffuser region 20 of the jet pump 4, the cross section of the deflection region 22, the cross section of the connecting piece 26 of the jet pump 4 and the cross section of the anode input 3 of the fuel cell 29 running orthogonally to the flow direction VII are at least approximately equal.

Furthermore, fig. 3 shows that a connection 26 is present between the closure cover 5 and the anode input 3 of the fuel cell 29. The connection 26 is formed as part of the main body 8 and, by means of the connection 26, the medium to be conveyed can flow out of the deflection region 22 into the anode inlet 3 of the fuel cell 29 without additional flow deflection and virtually without additional friction losses and/or flow losses and/or pressure losses. The jet pump 4 and/or the base body 8 are in fluid communication with the anode inlet 3, wherein the valve-jet pump assembly 2 can furthermore be mechanically fastened at least additionally to the fuel cell 29, in particular to the end plate 13. In this case, the valve jet pump assembly 2 and/or the side channel compressor 10 and/or the water separator 24 can be fastened to the fuel cell 29, in particular to the end plate 13, in a form-fitting and/or force-fitting and/or material-fitting manner. Furthermore, the component valve-jet pump assemblies 2 and/or the side channel compressor 10 and/or the water separator 24 can be arranged in a common housing or otherwise connected to one another.

In addition, the component base 8 and/or the closing cover 5 are made of a material or an alloy having a low specific heat capacity, wherein the component base 8 and/or the closing cover 5 of the injection pump 4 are made of a metal material or a metal alloy. Such exemplary embodiments of the parts are advantageous for rapidly heating the component, in particular in the flow region, and thus for avoiding ice bridges during a cold start procedure. In this case, it is also advantageous if the combined valve-jet pump assembly 2 has a heating element 11, by means of which rapid heating of the components of the delivery assembly 1 can be achieved.