Fuel cell exhaust gas system

Abstract

To provide a fuel cell exhaust gas arrangement, by means of which liquid carried in fuel cell exhaust gas, in particular water, can be extracted from the fuel cell exhaust gas.SOLUTION: Provided is a fuel cell exhaust gas arrangement for a fuel cell system, in particular in a vehicle. The fuel cell exhaust gas arrangement includes a fuel cell exhaust gas line 14 through which fuel cell exhaust gas can flow, and a separation unit 16 through which the fuel cell exhaust gas can flow. The separation unit 16 includes: an upstream line portion 38 of the fuel cell exhaust gas line 14 through which the fuel cell exhaust gas can flow in an exhaust gas mainstream direction; a downstream line portion 42 of the fuel cell exhaust gas line 14 adjoining the upstream line portion 38 in an opening region; a first liquid outlet opening in the opening region for outlet of liquid from the fuel cell exhaust gas flowing through the fuel cell exhaust gas line 14; and a swirl flow generating unit 54 in the upstream line portion 38.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an exhaust gas device for a fuel cell, via which process gas released from a fuel cell can be released into the environment as fuel cell exhaust gas. [Background technology]

[0002] It is known to use fuel cells, particularly in vehicles operated by electric motors, in order to be able to provide energy for operating the electric traction motor and other consumers of electrical energy in such vehicles. During operation of such a fuel cell, the anode region is supplied with hydrogen or anode gas that is highly hydrogen-rich. The cathode region is supplied with oxygen or oxygen-containing air as cathode gas. An electric current is generated while converting the hydrogen and oxygen into water. The hydrogen-rich anode exhaust gas and the highly water-containing cathode exhaust gas leave the fuel cell as fuel cell exhaust gas or process gas. During operation of the fuel cell, at least the cathode exhaust gas is discharged to the environment. During various operating phases, for example before the start of fuel cell operation, especially during purging of the anode region, the anode exhaust gas or the gas that is guided through the anode region in such operating phases can also be discharged to the environment. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to improve a fuel cell exhaust gas device for a fuel cell system, in particular in a vehicle, in such a way that liquids entrained in the fuel cell exhaust gas, in particular water, can be extracted from the fuel cell exhaust gas. [Means for solving the problem]

[0004] This problem is solved according to the invention by a fuel cell exhaust gas device for a fuel cell system, in particular in a vehicle, which comprises a fuel cell exhaust gas line through which the fuel cell exhaust gas can flow and a separation unit through which the fuel cell exhaust gas can flow, the separation unit being: - an upstream pipe section of the fuel cell exhaust gas pipe through which the fuel cell exhaust gas can flow in a mainstream exhaust gas direction; a downstream pipe section of a fuel cell exhaust gas pipe that is connected to an upstream pipe section in an opening area, a first liquid discharge opening in the opening area for discharging liquid from the fuel cell exhaust gas flowing through the fuel cell exhaust gas line; a vortex generating unit in an upstream pipe section; The above-mentioned problems are solved by a fuel cell exhaust gas device comprising:

[0005] The use of a vortex generating unit generates a vortex in the fuel cell exhaust gas upstream of the annular first liquid discharge opening. The centrifugal forces acting in such a vortex cause the liquid or liquid particles entrained in the fuel cell exhaust gas to move radially outward, which leads to a high liquid concentration in the radially outer region of the fuel cell exhaust gas flow. The liquid that accumulates in an increased form in the radially outer region of the fuel cell exhaust gas flow can then be discharged via the first liquid discharge opening.

[0006] The swirl generating unit may comprise flow deflection elements which are successive in the circumferential direction with respect to the flow axis of the upstream pipe section and angled with respect to the main exhaust gas flow direction in the upstream pipe section. Such swirl generating units, which are configured with a number of blade-shaped flow deflection elements, can be used, for example, as mixers in exhaust systems of diesel internal combustion engines, to induce swirl formation in the exhaust gas flow and thus assist the mixing of the exhaust gas with a reducing agent, typically a urea / water solution, injected into the exhaust gas upstream of an SCR catalytic converter unit.

[0007] For efficient flow deflection to generate vortex flows, the flow deflection elements may extend radially inward from the annular body of the vortex generating unit and / or circumferentially adjacent flow deflection elements may overlap circumferentially in the radially inner region.

[0008] A simple and inexpensive to realize, yet stable and corrosion-resistant, construction can be achieved if the vortex-generating unit with the annular body and the flow deflection elements is preferably designed as a one-piece sheet metal deformation part. In a particularly advantageous design with regard to corrosion resistance, manufacturing costs and freedom of design in shaping, for example, the vortex-generating unit with the annular body and the flow deflection elements can preferably be designed in one piece from a plastic material.

[0009] In order to reliably assist the discharge of liquid collecting in the radially outer region of the fuel cell exhaust gas flow, it is proposed that in the opening region, the upstream end section of the downstream pipe section is positioned in engagement with the downstream end section of the upstream pipe section such that a first liquid discharge opening is formed between the upstream end section of the downstream pipe section and the downstream end section of the upstream pipe section.

[0010] For this purpose, it may be advantageous if the downstream end section of the upstream pipe section is preferably configured with a substantially conical widening in the main exhaust gas flow direction and / or if the upstream end section of the downstream pipe section is preferably configured with a substantially conical widening in the main exhaust gas flow direction.

[0011] In order to reliably discharge the radially outer region of the fuel cell exhaust gas flow having a high liquid proportion, it may further be provided that the downstream pipe section has a smaller cross-sectional dimension at its upstream end than the cross-sectional dimension of the upstream pipe section in a longitudinal region located between the swirl generating unit and the downstream end of the upstream pipe section. For this purpose, the first liquid discharge opening may be designed substantially annularly.

[0012] The separation unit may comprise a separation unit housing, the opening area being arranged in the separation unit housing, so that the fuel cell exhaust gas device is substantially closed to the outside, particularly in the area where the first liquid discharge opening is also formed, and foreign matter cannot enter the fuel cell exhaust gas device.

[0013] Since it cannot be excluded that liquid is still present in the fuel cell exhaust gas downstream of the first liquid outlet opening despite the occurrence of vortex flows, it is proposed that the downstream pipe section has a second liquid outlet opening downstream of the opening area, for example, for this purpose the downstream pipe section can have a bent area with a bent apex to be positioned vertically downward in the separation unit housing, the second liquid outlet opening being arranged in the area of ​​the bent apex.

[0014] In a region of the separation unit housing which is to be positioned vertically downwards, a liquid collecting region with at least one liquid outlet opening may be provided for outlet of liquid from the separation unit housing.

[0015] In order to enable the release of liquid from the separation unit housing even when the temperature is relatively low, or essentially to prevent the liquid collecting in the liquid collecting area from freezing, a heating unit may be provided corresponding to the liquid collecting area for heating the liquid collecting in the liquid collecting area.

[0016] Since, for example, when purging the anode region of the fuel cell, there is a possibility that hydrogen-containing process gas will be released as fuel cell exhaust gas via the fuel cell exhaust gas system into the surroundings, in order to prevent excessively strong hydrogen accumulation in the separation unit housing, it is proposed that a hydrogen collection area is provided in an area of ​​the separation unit housing that should be positioned vertically at the top, which has at least one hydrogen outlet opening for outletting hydrogen from the separation unit housing.

[0017] Since the relatively light hydrogen is collected vertically approximately at the upper side within the separation unit housing, it is advantageous for the hydrogen collection area to include a wall area of ​​the separation unit housing that tapers vertically upward and for at least one hydrogen discharge opening to be provided in the upper top area of ​​the wall area in order to reliably release hydrogen outward.

[0018] During operation of the fuel cell, for example an electrically operated air compressor, e.g. a compressor, which pumps the process gas, generates noise that is unpleasant in the vicinity of the vehicle or even by the vehicle occupants, so it is proposed that a silencer unit, preferably downstream of the separation unit, is provided through which the fuel cell exhaust gas can flow.

[0019] The present invention will now be described in detail with reference to the accompanying drawings. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a side view showing a fuel cell exhaust gas system. [Diagram 2] 2 shows the fuel cell exhaust gas system shown in FIG. 1 with the separation unit and the silencer unit shown open; [Diagram 3] FIG. 2 is an enlarged view showing the silencer unit shown in FIG. [Figure 4] 3 is an enlarged perspective view of the separation unit shown in FIG. 2. FIG. [Diagram 5] 3 is an enlarged side view of the separation unit shown in FIG. 2. [Figure 6] FIG. 6 is a detailed view showing region VI of the separation unit shown in FIG. 5. [Figure 7] FIG. 2 is a perspective view showing a vortex generating unit. [Figure 8] FIG. 8 is an axial view of the vortex generating unit shown in FIG. 7. [Figure 9] FIG. 9 is a view corresponding to FIG. 8, showing an alternative configuration of the vortex generating unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In Figures 1 and 2, a fuel cell exhaust gas system, which can be used in particular in commercial vehicles or trucks, is generally designated by the reference number 10. The fuel cell exhaust gas system 10 has an inlet region 12 into which the fuel cell exhaust gas B can flow into a fuel cell exhaust gas line 14. Adjacent to the inlet region 12, the fuel cell exhaust gas system 10 has a separation unit 16 with a separation unit housing 18, which is shown cut or open in Figure 1. The fuel cell exhaust gas line 14 passes through the separation unit housing 18 and runs substantially upwards from the separation unit housing 18 in a vertical direction V when the fuel cell exhaust gas system 10 is installed in a vehicle. In an outlet region 20, the fuel cell exhaust gas B flows out of the fuel cell exhaust gas system 10.

[0022] A silencer unit 22 is located in the flow region between the separation unit 16 and the outlet region 20. This silencer unit 22 is shown in detail in FIG. 3. The silencer unit 22 comprises a tubular silencer housing 24 which surrounds a longitudinal section 26 of the fuel cell exhaust gas duct 14, which is located in the region of the silencer unit 22. This longitudinal section 26 is provided with openings 32, 34 which correspond to the two silencer chambers 28, 30 defined by the silencer unit housing 24, respectively, so that a connection is made between the internal volume of the fuel cell exhaust gas duct 14 in the longitudinal region 26 and the silencer chambers 28, 30. The silencer chambers 28, 30 can be separated from one another by a separating wall 36. It should be noted that, as shown in Fig. 3, there may be a different number and / or differently dimensioned openings 32, 34 arranged in the two silencer chambers 28, 30 in the longitudinal section 26. One or both silencer chambers 28, 30 may be partially or completely filled with a sound-insulating material, for example a foam or fibrous material. It should be noted that the silencer unit 22 shown in Fig. 3 is merely exemplary and may, quite naturally, be constructed in a different manner.

[0023] The separation unit 16 is explained in more detail below in relation to Figures 4 to 6.

[0024] The fuel cell exhaust gas line 14 is designed, for example, with a circular cross section and leads into the separation unit housing 18 downstream of the inlet region 12 with an upstream line section 38 extending elongately in the direction of the central flow axis S. A downstream line section 42 of the fuel cell exhaust gas line 14 is connected to this upstream line section 38 in an interior space 40 of the separation unit housing 18. In an opening region 44, an upstream end region 46 of the downstream line section 42 is positioned to engage with a downstream end region 48 of the upstream line section 38. For this purpose, the downstream end region 48 of the upstream line section 38 is designed to expand substantially conically along the central flow axis S, which may also substantially correspond to the central axis of the linear upstream line section 38. Similarly, the downstream pipe section 42 is preferably formed to expand substantially conically at its upstream end region 46, which extends into the downstream end region 48 of the upstream pipe section 38, along the central flow axis S and in the direction of the main exhaust gas flow direction H in which the fuel cell exhaust gas B flows through the upstream pipe section 38.

[0025] Between the end sections 46, 48, which extend radially substantially complementarily to one another, an annular first liquid outlet opening 50 is formed, via which the fuel cell exhaust gas line 14 opens into the interior space 40 of the separation unit housing 18. In the region of the first liquid outlet opening 50 or in the region where the two line sections 38, 42 connect with one another, the fuel cell exhaust gas line 14 can be covered by a housing element 52, which can open in a lower region in the vertical direction V into the interior space 40 of the separation unit housing 18.

[0026] A swirl generating unit 54 is arranged upstream of the first liquid discharge opening 50 or upstream of the radially expanding downstream end region 48 of the upstream pipe section 38 in this upstream pipe section 38. The swirl generating unit 54 comprises a number of blade-like flow deflection elements 56 arranged in succession in the circumferential direction about the central flow axis S and extending substantially in the radial direction. The flow deflection elements 56 are arranged at an angle with respect to the main exhaust gas flow direction H, i.e. neither parallel to the main exhaust gas flow direction H nor at an angle of 90° to the main exhaust gas flow direction H, so that the fuel cell exhaust gas B which should flow in the main exhaust gas flow direction H towards the swirl generating unit 54 is deflected in the circumferential direction when it impinges on the flow deflection elements 56, as a result of which swirls are generated.

[0027] It is suggested that such a swirl generating unit is used as a mixer, for example, in an exhaust gas system of a diesel internal combustion engine, where the exhaust gas flowing through such an exhaust gas system of a diesel internal combustion engine is stirred by the swirls generated in this way, which leads to an efficient mixing of the exhaust gas with a reducing agent, for example a urea / water-water solution, injected into the exhaust gas, and the mixture of exhaust gas and reducing agent thus formed is introduced into an SCR catalyst unit.

[0028] 7 to 9 show in more detail an embodiment of a swirl generating unit 54 which can be used in the fuel cell exhaust gas system 10. The swirl generating unit 54 can be formed, for example, in one piece from sheet metal material and has an annular or substantially cylindrical body 55, by means of which the swirl generating unit 68 can be held, for example, in the upstream pipe section 38. Starting from the body 55, the flow deflection elements 56, which are formed like blades and are arranged one behind the other in the circumferential direction, extend radially inwards so that they overlap in the circumferential direction, for example in their radially inner end regions. The flow deflection elements 56 are angled with respect to the main exhaust gas flow direction H, i.e. inclined at an angle other than 90°, so that the fuel cell exhaust gas flowing in the main exhaust gas flow direction H towards the swirl generating unit 54 is deflected in the flow deflection elements 56 in the circumferential direction with respect to the central flow axis S, so that swirls are generated.

[0029] In an alternative construction, the vortex generating unit 54 may be constructed from a plastic material, resulting in a lightweight, inexpensive to manufacture construction of the vortex generating unit 54, which is highly resistant to corrosion, particularly with respect to the water contained in the fuel cell exhaust gas.

[0030] The degree of deflection in the circumferential direction and thus the degree of vortices generated, or at the same time the degree of flow interruption caused by the flow deflection elements 56, depends on the inclination angle of the flow deflection elements 56 with respect to the main exhaust gas flow direction H. In the exemplary embodiment shown in Figs. 7 and 8, the flow deflection elements 56 are angled relatively small, i.e. oriented more in the direction of the main exhaust gas flow direction H, resulting in a less strong deflection of the fuel cell exhaust gas flow in the circumferential direction. Fig. 9 shows a configuration of the vortex generating unit 54 in which the flow deflection elements 56, which are further enlarged in the circumferential direction, are also angled more strongly with respect to the main exhaust gas flow direction. With the configuration of the vortex generating units 54 shown in Fig. 9, the fuel cell exhaust gas flow is deflected relatively strongly in the circumferential direction, which contributes to increasing the centrifugal forces acting on the liquid particles contained in the fuel cell exhaust gas.

[0031] The vortex generated by the deflection of the fuel cell exhaust gas flow in the circumferential direction generates centrifugal forces which exert a radially outward load on the liquid or droplets transported in the fuel cell exhaust gas B. This means that downstream of the vortex generating unit 54, in the radially outer region of the fuel cell exhaust gas flow, a relatively high concentration of liquid transported in the fuel cell exhaust gas B results. In particular, due to the transition between the two pipe sections 38, 42, which can be seen in Figure 5 and in particular the fact that the downstream pipe section 42 at its upstream end 58 has a smaller cross-sectional dimension, i.e., a diameter in a circular configuration, than the cross-sectional area of ​​the upstream pipe section 38 in the longitudinal region extending between the vortex generating unit 54 and the downstream end 60 of the upstream pipe section 38, in particular in the downstream end region 48 which is overlaid on the upstream end region 46 of the downstream pipe section 42, the liquid-rich portion of the fuel cell exhaust gas flow flows into the first liquid discharge opening 50, so that in particular the liquid entrained in this portion of the fuel cell exhaust gas also reaches the internal chamber 40 and is thus extracted from the remaining portion of the fuel cell exhaust gas flow, which flows into the downstream pipe section 42 at the loss of liquid.

[0032] A liquid collecting area 62 is formed in the lower area of ​​the separation unit housing 18 in the vertical direction V. In the illustrated embodiment, the liquid collecting area 62 is formed with an upwardly open container-like collecting vessel 64, which is inserted in the lower area of ​​the inner space 40 of the separation unit housing 18. A first liquid outlet opening 68 is formed in the area of ​​an outlet piece 66, which also passes through the separation unit housing 18. Via this first liquid outlet opening 68, the liquid can be discharged from the separation unit housing 18. A valve can, for example, be associated with the outlet piece 66, so that the liquid can be discharged at a defined time and, for example, returned to the fuel cell process.

[0033] A second liquid outlet opening 72, closed by a closing element 70, may be provided in the liquid collection container 64 or in the bottom region of the separation unit housing 18, via which the separation unit housing 18 can be completely emptied, for example when carrying out maintenance work.

[0034] Furthermore, an electrically excitable heating unit 74, for example a heating coil or the like, can be provided in the liquid collecting area 62, for example in the liquid collecting container 64 or in the bottom area of ​​the separation unit housing 18. This heating unit 74 makes it possible to heat the liquid collected in the liquid collecting area 62 and thus prevent this liquid from freezing, in particular at relatively low ambient temperatures, or to discharge the liquid from the liquid collecting area 62 in the event of freezing or even at low ambient temperatures. It is suggested that the liquid collecting area 62 can also be formed without the liquid collecting container 64 and that the outlet piece 66 can, for example, be formed directly in the separation unit housing 18.

[0035] Since it cannot be excluded that the part of the fuel cell exhaust gas B which flows into the downstream pipe section 42 still contains liquid despite the occurrence of eddies upstream of the opening region 44, a second liquid discharge opening 78 is formed in the downstream pipe section 42, for example in the region of the outlet pipe piece 76. In the longitudinal region which runs into the interior space 40 of the separation unit housing 18, the downstream pipe section 42 is formed with an elbow-shaped bending region 80. This bending region 80 forms a bending apex 82 which is or is to be positioned downward in the vertical direction V. The second liquid discharge opening 78 is arranged in the region of this bending apex 82, so that liquid which has collected downstream of the opening region 44, for example due to condensation, can collect downstream of the opening region 44 in the lowest region of the fuel cell exhaust gas line 14 and flow out of the fuel cell exhaust gas line 14 in the direction towards the liquid collecting region 62.

[0036] The need to extract liquid from the fuel cell exhaust gas B, in particular in order to make the liquid still available during fuel cell operation, arises primarily when the process gas leaving the cathode region of the fuel cell as fuel cell exhaust gas B, i.e. the cathode exhaust gas K, is guided through the fuel cell exhaust gas arrangement. At the start of operation of the fuel cell system, it may be necessary to purge the anode region of the fuel cell with gas. This gas, which carries away the hydrogen possibly still present in the anode region from the anode region, can likewise be guided as anode exhaust gas A into the fuel cell exhaust gas arrangement and can be discharged to the outside via this fuel cell exhaust gas arrangement. For this purpose, the fuel cell exhaust gas line 14 can have two inlet connections 84, 86 in the inlet region 12, which can be connected to the cathode region for receiving the cathode exhaust gas K or the anode region for receiving the anode exhaust gas A or can be connected to corresponding valve devices, so that one or both exhaust gas streams can be intentionally guided through the fuel cell exhaust gas arrangement 10. It should be noted that the fuel cell exhaust gas device 10 may or can connect the anode or cathode regions of multiple fuel cells or fuel cell stacks of a fuel cell system, for example via inlet connections 84, 86, respectively.

[0037] When the hydrogen-containing anode exhaust gas A is guided through the fuel cell exhaust gas device 14, it is basically possible that hydrogen can reach the inner chamber 40 of the separation unit housing 18 via the first liquid discharge opening 50 or the second liquid discharge opening 78. Hydrogen, which is significantly lighter than air or oxygen and nitrogen, collects in the separation unit housing 18 in the upper region of the inner chamber 40 in the vertical direction V. In order to avoid the occurrence of potentially dangerously high hydrogen concentrations, a hydrogen collecting area 88 is therefore formed in this region of the separation unit housing 18 positioned at the upper side in the vertical direction V. In this area, the separation unit housing 18 is formed with a wall area 92 that tapers upwards in the vertical direction V to an upper apex area 90. This wall area 92 guides the volatile hydrogen upwards in the manner of a funnel to the upper apex area 90. In the upper apex area 90, an outlet pipe 94 connects to the wall area 92, which preferably provides a permanently open hydrogen outlet opening 96. Thus, hydrogen introduced into the inner chamber 40 is guided into the top region 90 on the basis of its tendency to move upwards and is released into the surroundings through the hydrogen outlet opening 96 in essentially non-hazardous concentrations.

[0038] The provision of the hydrogen collecting area 88 formed with the substantially permanently open hydrogen discharge opening 96 further results in that the inner chamber 40 of the separation unit housing 18 is not permanently closed, which prevents the development of stagnation pressure in the fuel cell exhaust gas flow guided through the fuel cell exhaust gas line 14 and thus also allows the fuel cell exhaust gas B, which comprises a high liquid concentration, to flow out of the fuel cell exhaust gas line 14 via the first liquid discharge opening 50 substantially without backflow. The presence of the second liquid discharge opening 78 also prevents the development of such stagnation pressure in the inner chamber 40 of the separation unit housing 18.

[0039] The fuel cell exhaust gas system constructed according to the invention allows liquid particles, in particular water vapor or liquid droplets, entrained in the fuel cell exhaust gas to be extracted from the fuel cell exhaust gas efficiently and with little back pressure or pressure loss, which allows a particularly efficient operation of the fuel cell, since the fuel cell can be operated, for example, with a lower compressor power due to the lower back pressure or flow resistance in the region of the fuel cell exhaust gas system.

[0040] In the fuel cell exhaust gas system, in addition to the swirl generating unit, other system areas, such as the fuel cell exhaust gas line, the separation unit and the muffler unit, can be made, for example, substantially completely of plastic materials. This contributes to a lower weight of the fuel cell exhaust gas system and to low manufacturing costs. The construction of plastic materials also leads to very good corrosion resistance and a large degree of freedom in the design of the various components of the fuel cell exhaust gas system.

[0041] Furthermore, such a fuel cell exhaust gas device may also be used in connection with fuel cell systems operating stationary or on board, for example, ships and the like.

Claims

1. A fuel cell exhaust gas device for a fuel cell system, comprising a fuel cell exhaust gas pipeline (14) through which a fuel cell exhaust gas (B) can flow, and a separation unit (16) through which the fuel cell exhaust gas (B) can flow, the separation unit (16) being: an upstream pipe section (38) of the fuel cell exhaust gas pipe (14) through which the fuel cell exhaust gas (B) can flow in a mainstream exhaust gas direction (H); a downstream pipe section (42) of the fuel cell exhaust gas pipe (14), which connects to the upstream pipe section (38) at an opening region (44); a first liquid discharge opening (50) in said opening area (44) for discharging liquid from the fuel cell exhaust gas (B) flowing through said fuel cell exhaust gas line (14); - a vortex generating unit (54) in said upstream pipe section (38); Including, the downstream pipe section (42) has a second liquid discharge opening (78) downstream of the opening area (44); Fuel cell exhaust gas system.

2. 2. The fuel cell exhaust gas system of claim 1, wherein the swirl generating unit (54) comprises flow redirecting elements (56) that are circumferentially continuous with respect to a central flow axis (S) in the upstream pipe section (38) and angled with respect to the main exhaust gas flow direction (H) in the upstream pipe section (38).

3. 3. The fuel cell exhaust gas system according to claim 2, wherein the flow deflection elements (56) extend radially inward from an annular body (55) of the vortex generating unit (54) and / or adjacent flow deflection elements (56) in the circumferential direction overlap each other in the radially inner region.

4. 4. The fuel cell exhaust gas system according to claim 3, wherein the vortex generating unit (54) with the annular body (55) and the flow deflection element (56) is formed as a sheet metal deformation part or the vortex generating unit (54) is made substantially completely of plastic material.

5. A fuel cell exhaust gas device as described in claim 3, wherein the vortex generating unit (54) having the annular body (55) and the flow redirecting element (56) is formed as an integral sheet metal deformation processed part.

6. 6. The fuel cell exhaust gas system according to claim 1, wherein in the opening region (44), the upstream end section (46) of the downstream pipe section (42) is engaged and positioned in the downstream end section (48) of the upstream pipe section (38) such that the first liquid discharge opening (50) is formed between the upstream end section (46) of the downstream pipe section (42) and the downstream end section (48) of the upstream pipe section (38).

7. 7. The fuel cell exhaust gas system according to claim 6, wherein the downstream end section (48) of the upstream pipe section (38) is expanded in the mainstream exhaust gas direction (H) and / or the upstream end section (46) of the downstream pipe section (42) is expanded in the mainstream exhaust gas direction (H).

8. A fuel cell exhaust gas device as described in claim 6, wherein the downstream end section (48) of the upstream pipeline section (38) is formed by expanding into a cone shape in the exhaust gas mainstream direction (H) and / or the upstream end section (46) of the downstream pipeline section (42) is formed by expanding into a cone shape in the exhaust gas mainstream direction (H).

9. 6. A fuel cell exhaust gas system as claimed in claim 1, wherein the downstream pipe section (42) at its upstream end (58) has a cross-sectional dimension smaller than a cross-sectional dimension of the upstream pipe section (38) in a longitudinal region located between the vortex generating unit (54) and the downstream end (60) of the upstream pipe section (38) and / or the first liquid discharge opening (50) is formed substantially annularly.

10. 6. The fuel cell exhaust gas system according to claim 1, wherein the separation unit (16) comprises a separation unit housing (18), and the opening area (44) is arranged within the separation unit housing (18).

11. 11. The fuel cell exhaust gas system according to claim 10, wherein the downstream pipe section (42) includes a bent region (80) with a bent apex (82) to be positioned downward in the vertical direction (V) within the separation unit housing (18), and the second liquid discharge opening (78) is arranged in the region of the bent apex (82).

12. 11. The fuel cell exhaust gas system according to claim 10, wherein a liquid collecting area (62) having at least one liquid discharge opening (68, 72) for discharging liquid from the separation unit housing (18) is provided in a region of the separation unit housing (18) that is to be positioned downward in the vertical direction (V).

13. 13. The fuel cell exhaust gas system of claim 12, further comprising a heating unit (74) disposed in association with the liquid collecting area (62) for heating liquid collecting in the liquid collecting area (62).

14. 11. The fuel cell exhaust gas system according to claim 10, wherein a hydrogen collecting area (88) having at least one hydrogen discharge opening (96) for discharging hydrogen from the separation unit housing (18) is provided in an area of ​​the separation unit housing (18) that is to be positioned upward in the vertical direction (V).

15. 15. The fuel cell exhaust gas system of claim 14, wherein the hydrogen collecting area (88) comprises a wall area (92) of the separation unit housing (18) tapering upward in a vertical direction (V), and the at least one hydrogen outlet opening (96) is provided in an upper top area (90) of the wall area (92).

16. A fuel cell exhaust gas device as described in any one of claims 1 to 5, provided with a silencer unit (22) through which the fuel cell exhaust gas (B) can flow.

17. A fuel cell exhaust gas system as described in claim 16, wherein a silencer unit (22) is provided downstream of the separation unit (16).

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