Common hydrogen supply system for a hydrogen internal combustion engine and a fuel cell adapted to continuously supply the fuel cell

Abstract

Hydrogen supply system (1) common to a hydrogen internal combustion engine (3) and to a fuel cell (6) adapted to continuously supply the fuel cell (6), said supply system (1) being characterized in that it comprises a three-way valve (11): a first way (12) coming from a hydrogen storage (10), a second way (13) leading the hydrogen to the internal combustion engine (3) and a third way (14) leading the hydrogen to the fuel cell (6). Abstract figure: Figure 1

Description

Title of the invention: Hydrogen supply system common to a hydrogen internal combustion engine and a fuel cell adapted to continuously supply the fuel cell

[0001] The invention relates to a vehicle with an internal combustion engine and a fuel cell.

[0002] The invention relates in particular to a hydrogen supply circuit common to the internal combustion engine and the fuel cell.

[0003] Hydrogen is a gas particularly used as an energy vector in many devices, in particular for road, rail or air transport. In the case of motor vehicles, hydrogen can be used for pollution control in the exhaust line but also to power internal combustion engines, where it has the advantage of being able to generate high power with high efficiency, or for the production of electricity from fuel cells making it possible to obtain high efficiencies for low power and to generate electrical power without any regulated polluting emissions.

[0004] The vehicle can thus be equipped with a combination of a hydrogen internal combustion engine and a hydrogen fuel cell, as in the case of hybrid vehicles. These vehicles can then operate on hydrogen which would be stored in the vehicle in the form of a pressurized bottle for example.

[0005] Patent application DE10201930 discloses a hybrid vehicle comprising an internal combustion engine and a fuel cell system both operating with hydrogen. The fuel cell can also be used to power the electrical components of the internal combustion engine or other systems such as air conditioning.

[0006] In this application, the hydrogen is stored in liquid form in a tank and is conducted into the internal combustion engine through a supply line and into the fuel cell system through another line.

[0007] Under the effect of the supply circuit, the hydrogen is thus conveyed either to the combustion engine or to the fuel cell system by different pipes, so the user can decide to supply one of the two systems only or both at the same time.

[0008] However, this configuration raises a problem concerning the durability of the fuel cell system since different phenomena can lead to limiting the lifetime of a cell. One of these phenomena is carbon corrosion, i.e. the degradation of the catalytic support present in the electrodes. This This phenomenon appears in particular during prolonged stops and starts of the cell. Indeed, if the hydrogen supply is stopped for a sufficiently long time, air will diffuse from the anode side and when the cell starts, the injected hydrogen will lead to the formation of an air / hydrogen front leading to the acceleration of corrosion of the carbon present in the electrodes.

[0009] Thus, there is a need for a power supply system for an internal combustion engine and a fuel cell system that makes it possible to limit the corrosion phenomenon present in the catalytic electrodes.

[0010] For this purpose, the invention proposes a hydrogen supply system common to a hydrogen internal combustion engine and to a fuel cell adapted to continuously supply the fuel cell. The supply system comprises a three-way valve: a first way coming from a hydrogen storage, a second way leading the hydrogen to the internal combustion engine and a third way leading the hydrogen to the fuel cell.

[0011] The supply system being common to the combustion engine and the cell, is thus adapted to supply the cell continuously. Indeed, the use of the three-way valve then makes it possible to direct the flow of hydrogen either towards the combustion engine or towards the cell. Thus, by leaving the third way always open, the flow of hydrogen will necessarily pass through the fuel cell thus limiting the phenomenon of corrosion of the catalytic electrodes.

[0012] Furthermore, if a problem occurs in the circuit supplying the fuel cell, the second path leading to the combustion engine can be opened while the third path will be closed while the problem is corrected. Thus, the three-way valve also makes it possible to maintain a sufficient level of safety in the circuit so that in the event of a problem in the circuit, energy production can continue while it is corrected.

[0013] Advantageously and in a non-limiting manner, the hydrogen not consumed at the outlet of the cell is directed towards the second channel through a pipe.

[0014] The purpose of this pipe is to direct the hydrogen leaving the cell to the internal combustion engine through the second path. Thus, if the second path is closed by the three-way valve, the engine can still be supplied by this pipe.

[0015] Advantageously and in a non-limiting manner, the pipe leading to the second channel comprises a cut-off valve.

[0016] The use of a cut-off valve makes it possible to block access to the second channel so that when the user wants to use only the energy produced by the fuel cell, the cut-off valve will close to prevent any flow of hydrogen from circulating towards the internal combustion engine.

[0017] Advantageously and in a non-limiting manner, the power supply system comprises a recirculation loop for unconsumed hydrogen, said recirculation loop being located between the fuel cell and the cut-off valve.

[0018] Indeed, during operation of the cell, a portion of the hydrogen is not consumed and will therefore be found at the outlet thereof. According to the invention, the unconsumed hydrogen can be returned by a so-called "recirculation" loop to the conduit of the third path at the inlet of the cell to be reintroduced into the cell and consumed by the cell. The recirculation loop thus makes it possible to increase the efficiency of the fuel cell.

[0019] Advantageously and in a non-limiting manner, when only the fuel cell is in operation, the third path is open, the cut-off valve is closed and the second path is closed.

[0020] This configuration corresponds to the operating mode where only the fuel cell is supplied with recirculation of the unconsumed hydrogen.

[0021] This configuration has the advantage of generating electrical power usable by the engine without any polluting emissions while obtaining significant efficiency for low power. This operating mode is therefore used, for example, in town.

[0022] Advantageously and in a non-limiting manner, when only the combustion engine is in operation, the third way is closed, the cut-off valve is closed and the second way is open.

[0023] This configuration corresponds to the operating mode where only the internal combustion engine is powered without circulation of hydrogen in the cell.

[0024] The operating mode where only the combustion engine is powered has the advantage of generating high power with high efficiency. This operating mode is therefore used, for example, during long journeys on motorways.

[0025] Advantageously and in a non-limiting manner, when only the combustion engine is in operation or when the combustion engine and the fuel cell are in operation, the third path is open, the cut-off valve is open and the second path is closed.

[0026] This configuration corresponds to the operating mode where the fuel cell is continuously powered whether it generates a current or not.

[0027] The operating mode where the cell is continuously supplied limits the phenomenon of corrosion of the electrodes during start-up of the fuel cell.

[0028] The case where the fuel cell is powered by the combustion engine has the advantage of providing high power with high efficiency while reducing the polluting emissions generated by the internal combustion engine since part of the electrical power is generated by the fuel cell.

[0029] The invention also relates to a method of controlling a system power supply according to the invention. When only the fuel cell is in operation, the opening of the third path is controlled, and the closing of the cut-off valve and the second path are controlled. When only the combustion engine is in operation, the closing of the third path, the closing of the cut-off valve and the opening of the second path are controlled. When only the combustion engine is in operation or when the combustion engine and the fuel cell are powered, the opening of the third path, the opening of the cut-off valve and the closing of the second path are controlled.

[0030] The control method thus makes it possible to automate the supply system so that the three-way valve and the cut-off valve are open or closed depending on the operating mode to be applied.

[0031] The invention relates to a device for controlling the control method described above, the device comprises means for controlling the opening or closing of the three-way valve and the cut-off valve.

[0032] The control device according to the invention here comprises a processor.

[0033] The invention also relates to a motor vehicle equipped with hydrogen storage supplying an internal combustion engine and a fuel cell according to the supply system presented previously.

[0034] Other features and advantages of the invention will emerge from reading the description given below of several particular embodiments of the invention, given for informational purposes but not as a limitation, with reference to the single figure:

[0035] [Fig-1] is a diagram showing the hydrogen supply system of the fuel cell and the combustion engine as described by the invention.

[0036] [Fig. 1] shows an assembly 2 for producing energy to move a vehicle forward as well as the power supply system 1 of this assembly. The latter are installed in a motor vehicle.

[0037] The energy production assembly 2 comprises an internal combustion engine 3 operating on hydrogen and an electric motor 4.

[0038] The combustion engine 3 is connected to the transmission shaft 5 which is connected to the wheels, thus enabling the vehicle to move forward.

[0039] On the transmission shaft 5, the electric motor 4 is also shown. The electric motor 4 also makes it possible to set the transmission shaft 5 in motion to move the vehicle forward. The electric motor is supplied with electricity by the fuel cell 6 as well as a buffer battery 7.

[0040] Indeed, the fuel cell 6 generates a direct current which will be converted by a DC / DC converter 8. The current generated by the fuel cell 6 makes it possible to power the electric motor 4 but also to power the ancillary electrical circuits adapted to operate the various accessories of the vehicle.

[0041] However, when the fuel cell 6 is not operating, the ancillary electrical circuits are not supplied with energy, so a buffer battery 7 is used to produce sufficient energy for their operation. In addition, when the cell 6 starts up, the buffer battery 7 provides sufficient electrical energy for its operation from the start.

[0042] Before reaching the electric motor 4, the electrical energy is also converted by a DC / AC converter 9.

[0043] The fuel cell 6 and the internal combustion engine 3 are powered by hydrogen coming from a hydrogen storage 10. The storage 10 comprises an interface for its filling, not shown, as well as an output connected to the supply system 1.

[0044] The hydrogen supply system 1 is common to the fuel cell 6 and to the internal combustion engine 3. For this purpose, the supply system 1 comprises a three-way valve 11. The first way 12 corresponds to the pipe leading to the hydrogen storage 10. The second way 13 corresponds to the pipe leading to the inlet of the internal combustion engine 3. Finally, the third way 14 corresponds to the pipe leading to the inlet of the fuel cell 6.

[0045] In addition to being able to direct the flow into the correct conduit, the three-way valve 11 also makes it possible to block access to a conduit depending on the operating mode. The channel is then said to be closed if the hydrogen flow cannot be directed towards this channel.

[0046] At the outlet of the cell 6, the unconsumed hydrogen is directed by a pipe 15 which leads to two different pipes: a pipe 16 leads to the second path and another pipe 17 leads to a recirculation loop.

[0047] Thus, the supply system 1 comprises a recirculation loop 18 located at the level of the fuel cell 6. The recirculation loop 18 allows the hydrogen not consumed by the cell to be directed towards the pipe of the third path 14 to be reinjected at the inlet of the fuel cell 6. The operation will make it possible to increase the efficiency of the cell 6.

[0048] The supply system 1 also comprises a pipe 18 leading to the second channel 13. Thus, at the outlet of the cell, the unconsumed hydrogen can be directed to the internal combustion engine 3. The pipe has a cut-off valve 19 making it possible to open or close access to the second channel 13 depending on the operating mode.

[0049] The power supply system 1 has three possible operating modes.

[0050] The first operating mode corresponds to when only the fuel cell 6 is powered and the latter generates a current. In this first operating mode, the third channel 14 is open, the cut-off valve 19 is closed and the second track 13 is closed.

[0051] In this first operating mode, the hydrogen storage 10 supplies the fuel cell 6 with hydrogen via the third channel 14, access to which is open at the level of the three-way valve 11.

[0052] The cut-off valve 19 and the second channel 13 are closed so as not to supply the combustion engine 3 with hydrogen since the production of energy by this means is not necessary.

[0053] This first operating mode has the advantage of generating electrical power usable by the engine without any polluting emissions while obtaining significant efficiency for low power. This first operating mode is therefore used, for example, in town.

[0054] The second operating mode corresponds to when only the combustion engine 3 is powered and it provides energy. In this second operating mode, the third path is closed 14, the cut-off valve 19 is closed and the second path 13 is open.

[0055] In this second mode of operation, the hydrogen storage 10 supplies the internal combustion engine 3 with hydrogen via the second channel 13, access to which is open at the level of the three-way valve 11.

[0056] The cut-off valve 19 and the third channel 14 are closed so as not to supply the fuel cell 6 with hydrogen since the production of energy by this means is not necessary.

[0057] However, the second operating mode is not capable of continuously supplying the fuel cell. The corrosion phenomenon is therefore not limited. Thus, the second operating mode will not be favored to optimize the durability of the cell.

[0058] Finally, the third operating mode corresponds to when only the combustion engine 3 is powered and supplied with energy or when the combustion engine 3 and the fuel cell 6 are powered and supply energy. In this third operating mode, the third path 14 is open, the cut-off valve 19 is open and the second path 13 is closed.

[0059] The configuration adopted in this third mode of operation is to circulate the hydrogen in the cell whether it is consumed or not.

[0060] If the fuel cell 6 generates a current then part of the hydrogen flow will supply the cell 6 then the hydrogen not consumed at the outlet of the cell 6 will be partly recycled by the recirculation loop and it will be partly conducted towards the second path 13 to supply the combustion engine 3.

[0061] If the fuel cell 6 does not generate current, the hydrogen will only sweep the anode of the cell 6 before exiting. Then at the exit of the cell, the hydrogen will circulate at through the cut-off valve 19 to be led to the second channel 13 and thus supply the combustion engine 3.

[0062] In this configuration, the hydrogen circulates continuously in the fuel cell 6 even if it is not consumed by the latter. Thus, no air can penetrate into the enclosure and there is no air / hydrogen front which is created when the cell is started. The corrosion phenomenon is therefore limited which optimizes the durability of the fuel cell 6.

Claims

Claims

1. Hydrogen supply system (1) common to a hydrogen internal combustion engine (3) and a fuel cell (6) adapted to continuously supply the fuel cell (6), said supply system (1) comprises a hydrogen internal combustion engine (3), a fuel cell (6) and a three-way valve (11): a first way (12) coming from a hydrogen storage (10), a second way (13) leading the hydrogen to the internal combustion engine (3) and a third way (14) leading the hydrogen to the fuel cell (6), the supply system (1) being characterized in that it comprises a pipe (16) adapted so that the unconsumed hydrogen at the outlet of the cell (6) is directed towards the second way (13).

2. Supply system (1) according to claim 1, characterized in that the pipe (16) leading to the second path (13) comprises a cut-off valve (19).

3. Supply system (1) according to claim 2, characterized in that it comprises a recirculation loop (18) for unconsumed hydrogen, said recirculation loop (18) being located between the fuel cell (6) and the cut-off valve (19).

4. Power supply system (1) according to any one of claims 2 to 3, characterized in that the power supply system (1) is adapted so that when only the fuel cell (6) is in operation, the third path (14) is open, the cut-off valve (19) is closed and the second path (13) is closed.

5. A fuel system (1) according to any one of claims 2 to 4, characterized in that the fuel system (1) is adapted so that when only the combustion engine (3) is in operation, the third route (14) is closed, the cut-off valve (19) is closed and the second route (13) is open.

6. A power supply system (1) according to any one of claims 2 to 5, characterized in that the power supply system (1) is adapted so that when only the combustion engine (3) is in operation or when the combustion engine (3) and the fuel cell (6) are in operation, the third path (14) is open, the cut-off valve (19) is open and the second path (13) is closed.

7. A method of controlling a power supply system according to any one of claims 1 to 6, characterized in that when only the fuel cell (6) is in operation, the opening of the third way (14) and the closing of the cut-off valve (19) and the second way (13) are controlled; when only the combustion engine (3) is in operation, the closing of the third way (14), the closing of the cut-off valve (19) and the opening of the second way (13) are controlled; and when only the combustion engine (3) is in operation or when the combustion engine (3) and the fuel cell (6) are in operation, the opening of the third way (14), the opening of the cut-off valve (19) and the closing of the second way (13) are controlled.

8. Device for controlling the control method according to claim 7, characterized in that the device comprises means for controlling the opening or closing of the three-way valve and the cut-off valve.

9. Motor vehicle equipped with hydrogen storage (10) supplying an internal combustion engine (3) and a fuel cell (6) according to the supply system (1) claimed in claims 1 to 6.

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