Fuel cell vehicle and detection system for recognizing hydrogen in a fuel cell vehicle

Abstract

The present invention relates to a detection system (10a; 10b; 10c) for recognizing hydrogen (11) in a cavity (12) of a fuel cell vehicle (13). [Solution] The detection system includes a fuel cell system (15) having a fuel cell housing (16) and a purge air line (17) for purging the fuel cell housing (16), and a hydrogen sensor (14) external to the fuel cell housing (16), the purge air line (17) having a purge air outlet (18) for flowing purge air (19) from the fuel cell housing (16), the purge air outlet (18) being aligned to apply the purge air from the purge air line (17) to the hydrogen sensor (14). The present invention further relates to a fuel cell vehicle (13) having a detection system (10a; 10b; 10c) according to the present invention.

Description

[Technical field]

[0001] The present invention relates to a detection system for recognizing hydrogen in a cavity of a fuel cell vehicle, the detection system comprising a fuel cell system having a fuel cell housing and a purge air line for purging the fuel cell housing, and a hydrogen sensor external to the fuel cell housing, the purge air line having a purge air outlet for outletting purge air from the fuel cell housing. The present invention further relates to a fuel cell vehicle having such a detection system. [Background technology]

[0002] In a polymer electrolyte membrane (PEM) fuel cell system, hydrogen is converted into electrical energy with the aid of oxygen, producing waste heat and water. For this purpose, such a PEM fuel cell system typically comprises several stacked fuel cells, each having an anode supplied with hydrogen, a cathode supplied with air and a polymer electrolyte membrane arranged between the anode and the cathode. By stacking the fuel cells, the output voltage of the fuel cell system can be increased. Inside such a stack, there are supply channels for supplying hydrogen and air to the individual fuel cells and for carrying away the used moist air as well as the used anode exhaust gas from the fuel cell stack or the fuel cell system. Due to the design technology, the fuel cell stack has many meters of sealing points through which small amounts of hydrogen can escape from the fuel cell stack in the form of leakage. To ensure a defined transport of the exiting hydrogen, the fuel cell stack according to the prior art is surrounded by a fuel cell housing. The fuel cell housing is supplied with purge air in a defined manner from at least one point. At at least one other point, the purge air leaves the fuel cell housing again through a purge air line. The fuel cell housing is flushed, so to speak, with the purge air. In order to detect hydrogen in the fuel cell housing, in fuel cell systems according to the state of the art, a hydrogen sensor is installed in or on the purge air line. Furthermore, legal provisions require the installation of a further hydrogen sensor in closed or semi-closed cavities, for example in the engine compartment of fuel cell vehicles. In known systems, both hydrogen sensors detect hydrogen or the hydrogen concentration, which leads to the shutdown of the fuel cell system if a predefined limit value is detected to be exceeded. However, hydrogen sensors are expensive and lead to a complex system structure in fuel cell vehicles. Summary of the Invention

[0003] According to the invention, a simply constructed and cost-effective system for the reliable detection of unwanted hydrogen in a fuel cell system and / or a fuel cell vehicle is proposed. Such a system is in particular represented by a detection system according to claim 1 and by a fuel cell vehicle according to claim 10. Further preferred embodiments are evident from the dependent claims, the description and the drawings. The features described in the context of the detection system are also valid in the context of a fuel cell vehicle according to the invention and vice versa, so that cross-reference is always made and / or can be made to the disclosure relating to the individual inventive aspects.

[0004] In a first aspect of the invention, a detection system for recognizing hydrogen in a cavity of a fuel cell vehicle is provided. The detection system includes a fuel cell system having a fuel cell housing and a purge air line for purging the fuel cell housing, and a hydrogen sensor external to the fuel cell housing. The purge air line has a purge air outlet for flowing purge air out of the fuel cell housing. The purge air outlet is aligned to apply purge air from the purge air line to the hydrogen sensor.

[0005] The inventive structure of the purge air line or the purge air opening and the one of the hydrogen sensors makes it possible to omit a hydrogen sensor that would normally be provided inside the purge air line and / or inside the fuel cell housing, thus reducing costs and simplifying the system configuration of the fuel cell system. Furthermore, the omission of the hydrogen sensor and associated functional components creates design space for other functional components or allows for a more compact configuration of the fuel cell system.

[0006] The purge air outlet is preferably aligned to apply purge air from the purge air line directly to the hydrogen sensor, i.e. the purge air outlet and / or the purge air line are constructed and / or arranged to allow purge air exiting the purge air line through the purge air opening to reach the hydrogen sensor in a direct path and / or at least without obstruction.

[0007] A hydrogen sensor can be understood to be a sensor unit having a sensor housing and a sensor surface on the sensor housing. Thus, the functional units arranged in the hydrogen sensor described herein do not necessarily have to be arranged directly on the sensor surface, but may be arranged in the sensor housing. The hydrogen sensor is configured and arranged to recognize hydrogen and / or hydrogen concentration in the purge air and the cavity.

[0008] The purge air outlet is configured to allow purge air to flow out of the fuel cell housing to the surroundings of the fuel cell housing, and depending on the embodiment, can be understood as an end section of the purge air piping or as a functional component connecting the purge air piping to the hydrogen sensor.

[0009] The cavity may be configured as closed or semi-closed. The cavity can be understood to mean the design space of the fuel cell vehicle, for example the engine compartment. The purge air piping does not have to be configured in the form of an ideal passage and can in principle have any geometry, as long as it is suitable for correctly directing the purge air out of the fuel cell housing. The fuel cell system is not purged by the purge air piping, but with the aid of the purge air piping. The purge air piping can have a purge air inlet area, through which the purge air is introduced into the fuel cell housing, and a purge air outlet area, with the aid of which the purge air or the treated purge air can be led out of the fuel cell housing again.

[0010] The fuel cell system preferably comprises a plurality of fuel cell stacks, which are surrounded or substantially surrounded by a fuel cell housing. The hydrogen sensor may be configured in the form of a hydrogen microsensor with temperature-compensated, pressure-compensated and humidity-compensated signal evaluation.

[0011] In another embodiment of the invention, the detection system can have a purge air outlet facing the hydrogen sensor in order to apply the purge air from the purge air piping directly to the hydrogen sensor. The direct alignment of the purge air outlet and the purge air piping towards the hydrogen sensor allows a particularly accurate determination of the hydrogen concentration in the purge air. The mixing of other fluids can be prevented in a simple manner or at least reduced and / or adjusted to a desired amount. Alignment of the purge air outlet towards the hydrogen sensor can be understood as the normal vector of the purge air outlet pointing in the direction of and / or towards the hydrogen sensor. Furthermore, the normal vector of the purge air outlet can be aligned orthogonally or at an obtuse angle to the normal vector of the sensor surface of the hydrogen sensor, which, when assembled in the fuel cell vehicle, runs in the direction of gravity or substantially in the direction of gravity. Thereby, it can be achieved in a simple manner that the purge air reaches the hydrogen sensor as directly as possible.

[0012] In another embodiment of the invention, the detection system may comprise a collecting means for collecting hydrogen, which is arranged at the hydrogen sensor for guiding the collected hydrogen to the hydrogen sensor, by which a hydrogen-containing fluid that would not otherwise be able to reach the hydrogen sensor may also be guided to the hydrogen sensor, so that the detection system may recognize unwanted hydrogen leaks particularly efficiently.

[0013] In the detection system according to the invention, the collecting means may be configured in the shape of a funnel. The funnel shape allows for a simple, low-cost and nevertheless efficient manner in which ambient air and possibly also hydrogen can be collected and guided to the hydrogen sensor. The funnel-shaped collecting means tapers towards the hydrogen sensor. In particular, the funnel-shaped collecting means tapers against the direction of gravity when the detection system is in an integrated state in the fuel cell vehicle. The collecting means is preferably configured and / or arranged coaxially and / or concentrically with respect to the hydrogen sensor and / or the purge air outlet.

[0014] In the detection system according to the invention, the purge air outlet is preferably arranged at least partially in line with the hydrogen sensor. This allows the purge air emerging from the purge air line to strike the hydrogen sensor directly. In this way, a particularly informative measurement of the hydrogen content in the purge air can be performed. The purge air outlet faces directly or essentially directly towards the hydrogen sensor in this case. By the purge air outlet being arranged at least partially in line with the hydrogen sensor, it can be understood that an imaginary extension of the purge air line in the direction of the normal vector of the purge air outlet would strike the hydrogen sensor at least partially.

[0015] Furthermore, the detection system according to the invention can have a connection housing, which is connected to the purge air line and the hydrogen sensor in order to guide the purge air to the hydrogen sensor. By means of the connection housing, the purge air, and thus also the hydrogen in the purge air, can be guided directly to the hydrogen sensor, without the purge air having to be diverted, for example due to an obstacle, and thus being undesirably mixed with other fluids. By means of the connection housing, it is no longer necessary for the hydrogen sensor to be arranged directly at the purge air outlet, and yet an informative measurement of the hydrogen content in the purge air can be performed.

[0016] Furthermore, it may be advantageous if the connection housing in the detection system according to the invention is at least partially funnel-shaped, which preferably tapers towards the purge air outlet and correspondingly widens towards the hydrogen sensor, can act as a diffuser, so that the purge air flow from the purge air line can be slowed down and thus detected more effectively by the hydrogen sensor.

[0017] In addition, in the detection system according to the invention, the connection housing can have at least one gas intake opening for the inflow of hydrogen from the cavity into the connection housing. Thereby, it can be ensured in a simple and efficient manner that hydrogen from the surroundings of the fuel cell housing or hydrogen leaking from the fuel cell housing can also be determined by the hydrogen sensor. The connection housing preferably has a number of gas intake openings or holes for the inflow of hydrogen from the ambient air around the cavity or the fuel cell housing into the connection housing. Alternatively, the connection housing can be designed as a half-shell, with a closed part of the connection housing interconnecting the purge air line and the hydrogen sensor and an open part of the connection housing being understood to be at least one gas intake opening.

[0018] Furthermore, the purge air pipe of the detection system according to the invention may have a nozzle, and the connection housing may include an ejector adjacent to the nozzle, the ejector having a mixing chamber for providing a fluid mixture of purge air and hydrogen from the cavity, and a diffuser, the mixing chamber having at least one gas intake opening, and the diffuser being connected to the hydrogen sensor for supplying the fluid mixture to the hydrogen sensor, whereby ambient air from the surroundings of the fuel cell housing, or leaking hydrogen contained therein, can be sucked in an efficient manner into the mixing chamber and from there further guided to the hydrogen sensor or to its surface.

[0019] In yet another aspect of the invention, a fuel cell vehicle is presented having a cavity and a detection system as detailed above for recognizing hydrogen in the cavity, the fuel cell vehicle according to the invention thus offering the same advantages as those detailed for the detection system according to the invention, the fuel cell vehicle being preferably provided in the form of a road vehicle, in particular a car or truck.

[0020] Further ways of improving the invention will become apparent from the following description of various embodiments of the invention which are illustrated diagrammatically in the drawings, in which: All features and / or advantages which emerge from the claims, the detailed description and the drawings, including the design details and spatial arrangements, may form part of the invention both by themselves and in various combinations.

[0021] The figures respectively show, diagrammatically: [Brief description of the drawings]

[0022] [Figure 1] 1 is a detection system according to a first embodiment of the present invention. [Diagram 2] 2 is a detection system according to a second embodiment of the present invention. [Diagram 3] 3 is a detection system according to a third embodiment of the present invention. [Figure 4] 1 is a fuel cell vehicle having a detection system according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Components having the same function or mode of action are given the same reference numerals in each drawing.

[0024] FIG. 1 shows a detection system 10a for recognizing hydrogen 11 or hydrogen content of a cavity fluid in a cavity 12 of a fuel cell vehicle 13 shown in FIG. 4 according to a first embodiment. The detection system 10a includes a fuel cell system 15 having a fuel cell housing 16 and a purge air line 17 for purging the fuel cell housing 16. The detection system 10a further includes a hydrogen sensor 14 outside the fuel cell housing 16. As shown in FIG. 1, the purge air line 17 includes a purge air outlet 18 for outletting purge air 19 from the fuel cell housing 16. The purge air outlet 18 is aligned to apply purge air from the purge air line 17 to the hydrogen sensor 14. More precisely, the purge air outlet 18 faces the hydrogen sensor 14 to apply purge air from the purge air line 17 directly to the hydrogen sensor 14. As can be seen in FIG. 1, the purge air outlet 18 is spaced apart from the collection means 20 and the hydrogen sensor 14, so that hydrogen 11 or hydrogen-containing fluid from the cavity 12 can reach the hydrogen sensor 14 even outside the purge air line 17 without any problems.

[0025] In the embodiment shown in FIG. 1, the detection system 10a comprises a collection means 20 for collecting hydrogen originating from the surroundings of the fuel cell housing 16 or possibly ambient air containing hydrogen. The collection means 20 is arranged at the hydrogen sensor 14 in order to guide the collected hydrogen or ambient air to the hydrogen sensor 14. As shown in FIG. 1, the collection means 20 is configured in the shape of a funnel, which tapers towards the hydrogen sensor 14. Furthermore, it can be seen from the illustrated embodiment that the purge air outlet 18 is arranged in line with the hydrogen sensor 14. The hydrogen sensor 14 and / or the collection means 20 are preferably configured with outlet openings (not shown) for the outflow or outflow of the hydrogen 11 and / or the purge air 19 from the hydrogen sensor 14. This makes it possible to prevent fluid stagnation at the hydrogen sensor 14, which could lead to erroneous hydrogen detection.

[0026] 2 shows a detection system 10b according to a second embodiment. The illustrated detection system 10b has a connection housing 21 with an outlet opening on the right side of FIG. 2 for the outlet of the purge air 19 and the hydrogen 11 from the connection housing 21, which is connected to the purge air line 17 and the hydrogen sensor 14 for guiding the purge air 19 to the hydrogen sensor 14. The connection housing 21 is configured in the shape of a funnel. The connection housing 21 further has a gas inlet opening 22 for the inflow of the hydrogen 11 or the ambient air together with the hydrogen contained therein from the cavity 12 into the connection housing 21. The connection housing 21 shown in FIG. 2 can in principle also be considered as a component of the purge air line 17.

[0027] FIG. 3 shows a detection system 10c according to a third embodiment. In the illustrated detection system 10c, the purge air line 17 has a nozzle 23. The connection housing 21 has an ejector 24 adjacent to the nozzle 23, which has a mixing chamber 25 and a diffuser 26 for providing a fluid mixture 27 of purge air 19 and hydrogen 11 from the cavity 12. The mixing chamber 25 is thus configured with a gas intake opening 22, and the diffuser 26 is connected to the hydrogen sensor 14 for providing the fluid mixture 27 to the hydrogen sensor 14. The ejector 24 shown in FIG. 3 can also be considered in principle as a component of the purge air line 17. Additionally or alternatively, the nozzle 23 can be considered as part of the ejector 24. The connection housing 21 shown in FIG. 3 has outlet openings for the purge air 19 as well as the hydrogen 11 to flow out of the connection housing 21, just like the connection housing 21 shown in FIG. 2.

[0028] FIG. 4 shows a fuel cell vehicle 13 having a cavity 12 in the form of an engine compartment and a detection system 10a as shown in FIG.

[0029] The invention allows for other construction principles in addition to the embodiment shown, i.e. the invention should not be considered limited to the example described in connection with the drawings, for example the purge air line 17 does not have to extend beyond the fuel cell housing 16 but may end flush with it. [Explanation of symbols]

[0030] 10a;10b;10c Detection system 11 Hydrogen 12 Cavity 13 Fuel Cell Vehicles 14 Hydrogen sensor 15 Fuel Cell Systems 16 Fuel cell housing 17 Purge air piping 18 Purge air outlet 19 Purge air 20 Collection methods 21 Connection housing 22 Gas intake opening 23 Nozzle 24 Ejector 25 Mixing chamber 26 Diffuser 27 Fluid mixture

Claims

1. A detection system (10a; 10b; 10c) for recognizing hydrogen (11) in a cavity (12) of a fuel cell vehicle (13), comprising a fuel cell system (15) having a fuel cell housing (16) and a purge air line (17) for purging said fuel cell housing (16), and a hydrogen sensor (14) external to said fuel cell housing (16), said purge air line (17) having a purge air outlet (18) for outlet of purge air (19) from said fuel cell housing (16), the purge air outlet (18) is aligned to apply the purge air from the purge air line (17) to the hydrogen sensor (14); a connection housing (21) connected to the purge air pipe (17) and the hydrogen sensor (14) for guiding the purge air (19) to the hydrogen sensor (14); The connection housing (21) has at least one gas intake opening (22) for the flow of hydrogen (11) from the cavity (12) into the connection housing (21), the purge air piping (17) has a nozzle (23), the connection housing (21) includes an ejector (24) adjacent to the nozzle (23) having a mixing chamber (25) for providing a fluid mixture (27) consisting of the purge air (19) and the hydrogen (11) from the cavity (12) and a diffuser (26), the mixing chamber (25) having at least one gas intake opening (22), and the diffuser (26) being connected to the hydrogen sensor (14) to supply the fluid mixture (27) to the hydrogen sensor (14).

2. 2. The detection system (10a) according to claim 1, characterized in that the purge air outlet (18) is directed towards the hydrogen sensor (14) for applying the purge air from the purge air line (17) directly to the hydrogen sensor (14).

3. 3. The detection system (10a) according to claim 1 or 2, characterized in that it comprises a collecting means (20) for collecting hydrogen, arranged at the hydrogen sensor (14) for guiding the collected hydrogen to the hydrogen sensor (14).

4. 4. The detection system (10a) according to claim 3, characterized in that the collecting means (20) are configured in the shape of a funnel.

5. 5. The detection system (10a) according to any one of claims 1 to 4, characterized in that the purge air outlet (18) is arranged at least partially in line with the hydrogen sensor (14).

6. 6. The detection system (10b; 10c) according to any one of claims 1 to 5, characterized in that the connection housing (21) is at least partially configured in a funnel shape.

7. A fuel cell vehicle (13) having a cavity (12) and a detection system (10a; 10b; 10c) according to any one of claims 1 to 6 for recognising hydrogen (11) in said cavity (12).

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