AIR SUPPLY DEVICE FOR AN AIRCRAFT FUEL CELL DRIVE

Abstract

The invention is directed to an air supply device and to a method for supplying at least one fuel cell of an aircraft fuel cell drive with compressed air, wherein the aircraft fuel cell drive has an air supply device comprising a compressor arrangement, wherein ambient air is compressed by means of the compressor arrangement and a first part of the compressed air is supplied to the at least one fuel cell and a second part of the compressed air can be diverted to a cooling device of the at least one fuel cell by means of a bypass device.

Claims

1. An air supply device for an aircraft fuel cell drive having a compressor arrangement for supplying compressed air to the at least one fuel cell wherein at least one bypass device, by which one part of the compressed air is diverted at least for a time to a cooling device of the at least one fuel cell.

2. The air supply device according to claim 1, wherein the compressor arrangement comprises at least two compressor devices.

3. The air supply device according to claim 2, wherein the compressor arrangement has at least two stages.

4. The air supply device according to claim 1, wherein the bypass device is situated downstream from the first or downstream from a second or downstream from a further compressor stage.

5. The air supply device according to claim 1, further comprising at least one air cooler for cooling the compressed air.

6. The air supply device according to claim 1, further comprising a water separator situated downstream from the at least one fuel cell for separating water from the exhaust gas of the at least one fuel cell.

7. The air supply device according to claim 1, further comprising a control device for controlling the devices of the air supply device.

8. A method for supplying compressed air to at least one fuel cell of an aircraft fuel cell drive, wherein the aircraft fuel cell drive comprises an air supply device having a compressor arrangement, comprising the steps of: compressing of ambient air by the compressor arrangement; supplying at least one part of the compressed air to the at least one fuel cell; and diverting one part of the compressed air for the cooling of the at least one fuel cell depending on the cooling demand of the at least one fuel cell.

9. The method for supplying compressed air to at least one fuel cell of an aircraft fuel cell drive according to claim 8, further comprising the step of: controlling the compression performance of the compressor arrangement in dependence on the ambient conditions and/or the operating state of the at least one fuel cell.

10. The method for supplying compressed air to at least one fuel cell of an aircraft fuel cell drive according to claim 8, further comprising the step of: cooling the compressed air.

11. The method for supplying compressed air to at least one fuel cell of an aircraft fuel cell drive according to claim 8, further comprising the step of: humidifying the compressed air by supplying water.

12. An aircraft fuel cell drive having at least one fuel cell and an air supply device which is configured and arranged according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS FIGURES

[0045] Further features, benefits, and application possibilities of the invention will emerge from the following description in conjunction with the figures. Herein are shown:

[0046] FIG. 1 a schematic representation of an exemplary air supply device according to the invention for an aircraft fuel cell drive;

[0047] FIG. 2 a schematic representation of another exemplary air supply device according to the invention for an aircraft fuel cell drive;

[0048] FIG. 3 a schematic representation of yet another exemplary air supply device according to the invention for an aircraft fuel cell drive; and

[0049] FIG. 4 a schematic representation of a flow chart of the method according to the invention for supplying compressed air to at least one fuel cell of an aircraft fuel cell drive.

DESCRIPTION OF THE INVENTION

[0050] FIG. 1 shows a schematic representation of an exemplary air supply device 10 according to the invention for an aircraft fuel cell drive. The air supply device 10 comprises a compressor arrangement 11 for supplying compressed air to the at least one fuel cell 20. The compressor arrangement 11 comprises a compressor device 12, which is operated by an electric motor 13.

[0051] The air supply device 10 is supplied with ambient air through an air inlet 2, which is then taken through an air filter 3 to a compressor device 12 of the compressor arrangement 11. In the compressor device 12, the ambient air is compressed and taken in a supply line 4 to the at least one fuel cell 20.

[0052] On the supply line 4 of the air supply device 10 is arranged a bypass device 16, by which a portion of the compressed air can be diverted for at least some of the time to a cooling device 17 of the at least one fuel cell 20. The bypass device 16 comprises a branching device 15 situated downstream from the compressor device 12 and thus downstream from the first and only compressor stage 21, by which some of the compressed air can be diverted from the air flow. By the bypass device 16, the compressed air can be taken to the cooling device 17, serving there for the cooling of the at least one fuel cell 20.

[0053] After the compressor arrangement 21 of the air supply device 10 and before the at least one fuel cell 20 there is arranged an air cooler 18, which serves for the cooling of the compressed air. With the aid of the air cooler 18, the efficiency of the at least one fuel cell 20 can be increased, since fuel cells undergoing a flow through them of a cooler air mass flow will have more air and thus more oxidizing agent flowing through them, so that higher power can be generated.

[0054] In the exhaust gas flow after the fuel cell 20 there is furthermore arranged an exhaust gas cooler 19 for cooling the exhaust gas coming from the fuel cell 20. This cooling process serves on the one hand for recovering the heat and thus the energy and, furthermore, it reduces the formation of condensation trails during flight operation. In addition, the exhaust gas flow coming from the at least one fuel cell 20 is taken across a water separator 31 arranged in the air flow after the fuel cell 20, which separates water from the exhaust gas of the at least one fuel cell 20. At least a portion of the water separated by the water separator 31 is taken to a humidifier device 32, which thereby humidifies the compressed air flow supplied to the fuel cell 20 and also lowers its temperature in addition. Finally, the spent ambient air is put out to the surroundings via the air outlet 6.

[0055] The air supply device 10 furthermore comprises a control device 40 for controlling the devices of the air supply device 10. The devices of the air supply device 10 which are controlled by the control device 40 include for example, in the embodiment shown in FIG. 1, the compressor arrangement 21, the branching device 15, the humidifier device 32, the air cooler 18, the at least one fuel cell 20, the exhaust gas cooler 19 and the water separator 31, being shown connected to the control device 40 by signal lines 41 shown as broken lines.

[0056] FIG. 2 shows a schematic representation of another exemplary air supply device 10 according to the invention for an aircraft fuel cell drive. The air supply device 10 here comprises a two-stage compressor arrangement 11 for supplying compressed air to the at least one fuel cell 20. The first compressor stage 21 of the compressor arrangement 11 comprises two parallel arranged compressor devices 12, which are powered by an electric motor 13, and the second compressor stage 22 of the compressor arrangement 11 likewise comprises a compressor device 14 powered by an electric motor 23.

[0057] As in the embodiment of FIG. 1, ambient air is supplied to the air supply device 10 via an air inlet 2, and it is then taken through an air filter 3 to the first compressor stage 21 of the compressor arrangement 11. The compressor devices 12 compress the ambient air and deliver it in parallel to a supply line 4. In the supply line 4 there is arranged an air cooler 28, which serves for the cooling of the air compressed in the first compressor stage 21. The cooled compressed air is then further compressed by the second compressor stage 22 and taken on to the at least one fuel cell 20.

[0058] In the embodiment of the air supply device 10 shown as an example in FIG. 2, the branching device 15 of the bypass device 16 is situated after one of the compressor devices 12 of the first compressor stage 21. Other than this, the layout and function of the bypass device 16 in FIG. 2 corresponds to the layout and function of the bypass device 16 of FIG. 1.

[0059] As in the embodiment of the air supply device 10 represented in FIG. 1, there are arranged in the exhaust gas flow after the fuel cell 20 of the air supply device 10 represented in FIG. 2 an exhaust gas cooler 19, a water separator 31 and an air outlet 6. Similar to the embodiment of FIG. 1, at least a portion of the separated water is taken to a humidifier device 32, in order to humidify the compressed air flow supplied to the fuel cell 20.

[0060] The air supply device 10 described in connection with FIG. 2 also comprises a control device 40, not shown, for controlling the devices of the air supply device 10.

[0061] FIG. 3 shows a schematic representation of yet another exemplary air supply device 10 according to the invention for an aircraft fuel cell drive, the layout of which corresponds in large part to the layout of the air supply device 10 represented in FIG. 2. The basic layout of the air supply devices 10 represented in FIGS. 2 and 3 differs basically in the arrangement of the bypass device 16 and in the fact that the air supply device 10 of FIG. 3 has no air cooler 28 for cooling the air compressed in the first compressor stage 21. Accordingly, the differences between the two embodiments will be described in the following.

[0062] In the exemplary embodiment of the air supply device 10 represented in FIG. 3, the branching device 15 of the bypass device 16 is situated after the second compressor stage 22 in the supply line 4, so that in this embodiment more heavily compressed air is taken via the bypass device 16 to the cooling device 17, and serving there for the cooling of the at least one fuel cell 20.

[0063] The air supply device 10 described in connection with FIG. 3 also comprises a control device 40, not shown, for controlling the devices of the air supply device 10.

[0064] FIG. 4 shows a schematic representation of a flow chart of the method according to the invention for supplying compressed air to at least one fuel cell 20 of an aircraft fuel cell drive, the aircraft fuel cell drive having an air supply device 10 with a compressor arrangement 11.

[0065] The method according to the invention involves the following steps: in a first step a), ambient air is compressed by the compressor arrangement 11, and in a second step b) at least a portion of the compressed air is taken to the at least one fuel cell 20. In a further step c), a portion of the compressed air is diverted for cooling of the at least one fuel cell 20, depending on the cooling demand of the at least one fuel cell 20.

[0066] In an optional embodiment of the method, in a step d) the compression performance of the compressor arrangement 11 is controlled in particular depending on the ambient conditions and/or the operating state of the at least one fuel cell 20. In a further optional embodiment of the method, in a step e) the compressed air is cooled and in a further optional embodiment of the method in a step f) the compressed air is humidified by the adding of water.