FUEL EXTRACTION SYSTEM, FUEL TANK APPARATUS HAVING A FUEL EXTRACTION SYSTEM, AND FUEL CELL SYSTEM HAVING A FUEL EXTRACTION SYSTEM

Abstract

A fuel extraction system for extracting a gaseous fuel from a fuel tank. The fuel extraction system includes a conveying device which is configured to convey gaseous fuel and to bring it from a first pressure level to a second pressure level, a first line which is configured to connect the conveying device fluidically to the interior of the fuel tank, a buffer tank which is configured to store the fuel at the second pressure level, and which has a first outlet and a second outlet, at least one valve with a pneumatic actuating device, and a second line which is connected to the first outlet of the buffer tank and is configured to conduct a part of the fuel at the second pressure level to the pneumatic actuating device of the at least one valve. Furthermore, a fuel tank apparatus and a fuel cell system are described.

Claims

1. A fuel extraction system for extracting a gaseous fuel from a fuel tank, comprising: a conveying device which is configured to the convey gaseous fuel and to bring the gaseous fuel from a first pressure level to a second pressure level; a first line which is configured to connect the conveying device fluidically to the interior of the fuel tank; a buffer tank which is configured to store the fuel at the second pressure level, and which has a first outlet and a second outlet; at least one valve with a pneumatic actuating device; and a second line which is connected to the first outlet of the buffer tank and is configured to conduct a part of the fuel at the second pressure level to the pneumatic actuating device of the at least one valve.

2. The fuel extraction system according to claim 1, the pneumatic actuating device of the at least one valve being configured to open and to close the valve exclusively by means of the gaseous fuel at the second pressure level.

3. The fuel extraction system according to claim 1, comprising, furthermore: a third line which is connected to the second outlet of the buffer tank and is configured to conduct the fuel at the second pressure level to a consumer, the third line having a section which leads through an interior of the fuel tank and which comprises a first heat exchanger for evaporating liquid fuel in the fuel tank.

4. The fuel extraction system according to claim 3, a first valve of the at least one valve being arranged in the third line downstream of the section through the interior of the fuel tank, and being configured to regulate a throughflow quantity of the fuel through the third line.

5. The fuel extraction system according to claim 3, comprising, furthermore: a bypass line which, outside the fuel tank, bypasses the section of the third line through the interior of the fuel tank; and a second valve of the at least one valve which is arranged in the bypass line and is configured to regulate a throughflow quantity of the fuel through the bypass line.

6. The fuel extraction system according to claim 1, comprising, furthermore: a second heat exchanger which is configured to utilize the gaseous fuel as a heat sink for a coolant of a cooling circuit.

7. The fuel extraction system according to claim 3, comprising, furthermore: a third heat exchanger which is configured to couple the gaseous fuel in the first line thermally to the gaseous fuel in the third line.

8. The fuel extraction system according to claim 1, comprising, furthermore: a main valve which is arranged in the second line and which is configured to regulate a throughflow quantity of the fuel at the second pressure level through the second line.

9. A fuel tank apparatus, comprising: a fuel tank for storing a fuel in a liquid and gaseous state; and a fuel extraction system according to claim 1.

10. The fuel tank apparatus according to claim 9, comprising, furthermore: a feed line into the fuel tank for filling the fuel tank with liquid fuel; and a third valve of the at least one valve which is arranged in the feed line and is configured to regulate a throughflow quantity of the fuel feed through the line.

11. A fuel cell system, comprising: a fuel cell which is operated by way of gaseous fuel; and a fuel extraction system according to claim 1.

12. A fuel cell system, comprising: a fuel cell which is operated by way of gaseous fuel; and a fuel tank apparatus according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] One preferred embodiment of the invention will now be described in greater detail on the basis of the appended diagrammatic drawing.

[0026] The FIGURE shows a fuel extraction system, a fuel tank apparatus and a part of a fuel cell system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The fuel cell system 1 which is shown in the single FIGURE (at least in sections) comprises a fuel cell 2 which is operated by way of gaseous fuel. The latter can be stored in a fuel tank 101 of the fuel tank apparatus 10. The fuel tank 101 contains gaseous fuel and liquid fuel (shown using crosshatched lines in the fuel tank 101).

[0028] In order to extract the fuel from the fuel tank 101, a fuel extraction system 100 comprises a conveying device 110 which is connected via a first line 105 to the interior of the fuel tank 101. The first line 105 preferably begins in an upper region of the fuel tank 101, in order to conduct only gaseous fuel and not liquid fuel from the fuel tank 101. The conveying device 110 can raise the gaseous fuel from a first pressure level which prevails in the fuel tank 101 to a second pressure level. For example, the conveying device 110 can raise the pressure of the gaseous fuel from approximately 2 bar to approximately 20 bar.

[0029] Subsequently, the gaseous fuel at the second pressure level is (buffer) stored in a buffer tank 120. The buffer tank 120 has a first outlet 121, to which a second line 125 is connected. Via the second line 125, a part of the fuel at the second pressure level is conducted to a pneumatic actuating device 131 of at least one valve 130. For this purpose, the second line 125 can comprise a main valve 126, the second line 125 branching off downstream of the main valve 126 and forming feed lines to the respective valve 130a, 130b, 130c. It goes without saying that further valves can also have a pneumatic actuating device 131 outside the fuel extraction system, which pneumatic actuating device 131 is actuated via the fuel from the second line 125. Each of the actuating devices 131 of the at least one valve 130 can be opened and closed exclusively via the fuel from the second line 125. As an alternative, the opening or closing can also take place automatically via a spring element or another mechanical actuator.

[0030] A third line 135 is connected to a second outlet 122 of the buffer tank 120. The third line 135 serves primarily to feed the fuel to a consumer, for example a fuel cell 2.

[0031] A first heat exchanger 140 can be provided in the third line 135, which first heat exchanger 140 is situated in a section 135a of the third line 135 through the interior of the fuel tank 101. By way of the first heat exchanger 140, thermal energy can be introduced into the liquid fuel in the fuel tank 101, as a result of which the fuel evaporates.

[0032] Furthermore, a second heat exchanger 150 can be provided in the third line 135, in which second heat exchanger 150 the fuel in the third line 135 serves as a heat sink for a coolant of a cooling circuit 155. The cooling circuit 155 can be used, for example, for cooling the fuel cell 2. As an alternative or in addition, a third heat exchanger 151 can be provided which couples the gaseous fuel in the first line 105 thermally to the gaseous fuel in the third line 135. As a result, the gaseous fuel in the first line 105 can be kept in the gaseous state, or residues of liquid fuel in the third heat exchanger 151 can be evaporated. The FIGURE shows the second heat exchanger 150 and the third heat exchanger 151 separately from one another. It goes without saying that this can be a combined heat exchanger which couples the fuel in the first line 105, the fuel in the third line 135 and the coolant of the cooling circuit 155 to one another thermally.

[0033] In order to regulate the quantity of the fuel to be evaporated in the fuel tank 101 by way of the first heat exchanger 140, a bypass line 136 is provided which, outside the fuel tank 101, bypasses the section 135a of the third line 135, and therefore bypasses the first heat exchanger 140. The bypass line branches off from the third line 135 upstream of the section 135a of the third line 135 in the interior of the fuel tank 101, and opens into the third line 135 again downstream of the section 135a. A second valve 130b of the at least one valve 130 which is arranged in the bypass line can regulate a throughflow quantity of the fuel through the bypass line 136, as a result of which a throughflow quantity of the fuel through the section 135a through the interior of the fuel tank 101 and the first heat exchanger 140 is also regulated.

[0034] A first valve 130a is provided in the third line 135 downstream of the section 135a and/or the bypass line 136. The fuel which is conducted as far as the first valve 130a is subsequently conducted through a further section 135b of the third line 135 to the consumer, for example a fuel cell 2. For this purpose, the first valve 130a regulates a throughflow quantity of the fuel through the further section 135b of the third line 135. The first valve 130a can also be a pressure reduction valve. For example, the gaseous fuel upstream of the first valve 130a can have approximately the second pressure level (with corresponding pressure losses by way of lines 135, 135a, 136, heat exchangers 140, 150, 151 and/or valves 130), whereas the first valve 130a regulates the gaseous fuel for the further section 135b of the third line 135 to the pressure level which is required by the consumer 2.

[0035] In addition to the fuel tank 101, the fuel tank apparatus 10 can also provide a protective tank 102. The latter serves primarily to collect fuel from the fuel tank 101, which fuel can escape from the latter. The protective tank 102 can collect the fuel even in the case of an undesired leak of the fuel tank 101. Fuel can be output safely from the protective tank 102 into the surroundings via corresponding safety lines 103, 104.

[0036] Furthermore, the fuel extraction system 100 can be arranged within the protective tank 102 (with the exception of the fuel tank 101). As a result, fuel which escapes from one of the components which are shown on the right-hand side next to the protective tank 102 in the FIGURE can be collected and discharged safely. As an alternative, the elements of the fuel extraction system 100, in which fuel at the second pressure level is contained, can be arranged in a separate protective vessel (shown using dashed lines). For the case where fuel at the second pressure level escapes, the fuel can be returned automatically into the fuel tank 101 via a corresponding feed line into the fuel tank 101, for example a feed line 138 for gaseous fuel or a separate feed line, since the fuel in the fuel tank 101 is stored at the first, lower pressure level. Merely by way of example, the buffer tank 120, the third line 135 (with the exception of the section 135a in the interior of the fuel tank 101), the bypass line 136, the second line 125 and the valves 126, 130 can be arranged within the protective vessel (shown using dashed lines).

[0037] Furthermore, the fuel tank apparatus 10 can provide a feed line 137 for liquid fuel for filling the fuel tank 101 with liquid fuel. A third valve 130c can be arranged in the feed line 137, which third valve 130c likewise has a pneumatic actuation means 131 which is supplied with and actuated by way of fuel at the second pressure level via the second line 125. The FIGURE additionally shows a feed line 138 for gaseous fuel. The feed line 138 can likewise be opened and closed via a corresponding valve (not shown separately).

[0038] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.