Method for managing hybrid drive train of hydrogen motor vehicle and associated drive train

Abstract

The invention relates to a method for managing a hybrid drive train of a hydrogen motor vehicle, comprising an internal combustion engine (2), a fuel cell (3), a hydrogen storage tank (14) and a line C1 connecting an air outlet (10) of the fuel cell (3) to an air inlet (12) of the internal combustion engine (2), the line having a shut-off valve V1, the method comprises the following steps: a) controlling the shutdown of the fuel cell (3); b) shutting down the internal combustion engine (2); c) opening the shut-off valve V1 when the fuel cell (3) and the internal combustion engine (2) are shut down; and d) operating the internal combustion engine (2) without injecting hydrogen from the tank (14) in order to draw the fluid present in the fuel cell (3) into the internal combustion engine (2) via the line C1.

Description

[0001] The present invention generally relates to motor vehicles using hydrogen as an energy source and, more particularly, to hybrid motor vehicles incorporating an internal combustion engine and a fuel cell, both of which are supplied with hydrogen.

[0002] More precisely, the invention relates to a method for managing the hybrid powertrain of a hydrogen vehicle, the hybrid powertrain including an internal combustion engine and a fuel cell, and also relates to the associated power train.

[0003] In order to propose an alternative to fossil fuels, hydrogen technology has generated great interest, especially in the automotive industry.

[0004] There are now motor vehicles of various architectures using hydrogen as an energy source.

[0005] According to an example, document US 20140001033 describes a system using hydrogen as a secondary energy source. To this end, water is pumped into a fuel cell, which generates a mixture of hydrogen and oxygen. The resulting hydrogen is mixed with the fuel supplied to the internal combustion engine.

[0006] Other vehicles use hydrogen as the sole energy source.

[0007] In particular, in reverse operation, the fuel cell can be connected to a battery, and the fuel cell supplies the battery with the current generated from hydrogen and oxygen. Thus, the battery can deliver electrical energy to an electric motor, especially during the starting phase or transient operation phase.

[0008] The advantages of the fuel cell lie particularly in that it has very high efficiency under partial load (i.e., during low power requests) and generates electrical power that can be used for an electric motor to propel the vehicle without any regulated polluting emissions.

[0009] The operation of other vehicles is based solely on the combustion of hydrogen in an internal combustion engine.

[0010] The advantage of the internal combustion engine is its ability to generate high power levels with high efficiency under high load conditions. However, on the other hand, the internal combustion engine produces a small amount of regulated pollutants.

[0011] In order to benefit from the advantages of these two architectures, some hybrid hydrogen vehicles combine an internal combustion engine and an electric motor connected to a battery, which battery is itself powered by a fuel cell. Thus, hydrogen is used as the sole energy source for both the internal combustion engine and the fuel cell.

[0012] However, when the fuel cell shuts down, there may still be water inside it. The long-term presence of water during shutdown affects its stability and service life.

[0013] In particular, when the external temperature is negative, the remaining water freezes, which interferes with fuel cell operation and prevents its restart.

[0014] Therefore, an object of the present invention is to remedy these drawbacks and propose a strategy for shutting down a fuel cell while ensuring optimal restart of the fuel cell regardless of whether the external temperature is positive or negative, which aims to extend its service life and ensure its stability.

[0015] Therefore, a method for managing a hybrid powertrain of a hydrogen-powered vehicle is proposed, the hybrid powertrain including an internal combustion engine, a fuel cell, a hydrogen storage tank, and a pipeline C1 that connects the air outlet of the fuel cell to the air inlet of the internal combustion engine and includes a shut-off valve V1, the method comprising the following steps:

[0016] a) Cause the shutdown of the fuel cell;

[0017] b) Cause the shutdown of the internal combustion engine;

[0018] c) When the fuel cell and the internal combustion engine have been shut down, open the shut-off valve V1; and

[0019] d) When the shut-off valve V1 is open, operate the internal combustion engine without injecting hydrogen from the tank in order to suck the fluid present in the fuel cell towards the internal combustion engine via the pipeline C1.

[0020] In an embodiment, the powertrain may include a pipeline C2 that connects the hydrogen outlet of the fuel cell to the air inlet of the internal combustion engine and includes a shut-off valve V2, and step c) includes opening the shut-off valve V2 and the valve V1 in order to also suck the fluid present in the fuel cell towards the internal combustion engine via the pipeline C2 in step d).

[0021] According to one feature, the operation of the internal combustion engine in step d) may be maintained for a predetermined time interval.

[0022] According to another feature, the operation of the internal combustion engine in step d) may be maintained until the humidity level in the fuel cell is less than or equal to a predetermined threshold.

[0023] The present invention also relates to a hybrid powertrain for a hydrogen-powered vehicle, the hybrid powertrain including:

[0024] An internal combustion engine;

[0025] A fuel cell;

[0026] A hydrogen storage tank;

[0027] Pipeline C1, which connects the air outlet of the fuel cell to the air inlet of the internal combustion engine and includes a shut-off valve V1 for selectively allowing the fluid present in the fuel cell to flow from said air outlet to the internal combustion engine; and

[0028] A control device configured to cause the opening of the shut-off valve V1 when the fuel cell and the internal combustion engine have been shut down, and to operate the internal combustion engine without injecting hydrogen from a storage tank so as to suck the fluid present in the fuel cell towards the internal combustion engine via the pipeline C1.

[0029] In an embodiment, the powertrain may include a pipeline C2, which connects the hydrogen outlet of the fuel cell to the air inlet of the internal combustion engine and includes a shut-off valve V2 for selectively allowing the fluid present in the fuel cell to flow from said hydrogen outlet to the internal combustion engine, the control device being configured to cause the opening of the shut-off valve V2 as well as the valve V1, and then to start the internal combustion engine without injecting hydrogen so as to also suck the fluid present in the fuel cell towards the internal combustion engine via the pipeline C2.

[0030] Advantageously, the powertrain may include a recirculation unit connected to the fuel cell to recirculate hydrogen from the hydrogen outlet towards the hydrogen inlet of the fuel cell, the recirculation unit being connected to the pipeline C2.

[0031] Preferably, the pipeline C2 is connected to the pipeline C1 upstream of the air inlet of the internal combustion engine.

[0032] Preferably, the powertrain includes at least one condenser positioned on the pipeline C1 and / or the pipeline C2.

[0033] Advantageously, the internal combustion engine may be coupled to a turbo-compressor positioned on the pipeline C1, upstream of the air inlet of the internal combustion engine and downstream of the fuel cell.

[0034] The invention also relates to a motor vehicle comprising a powertrain as described above.

[0035] Further objects, advantages and features will be revealed by the following description given solely by way of illustration and with reference to the drawings, in which:

[0036] Figure 1 shows a hybrid powertrain for a hydrogen motor vehicle according to an embodiment of the invention.

[0037] Figure 2 ​​shows a hybrid powertrain for a hydrogen motor vehicle according to another embodiment of the present invention.

[0038] Moreover, the expression "at least one" used in this specification is equivalent to the expression "one or more".

[0039] In the present invention, the terms "upstream" and "downstream" are understood with respect to the flow direction of the fluid aspirated by the internal combustion engine from the fuel cell.

[0040] Figure 1 Shows a powertrain 1 for a motor vehicle.

[0041] In the example shown, hydrogen is the only energy source for the motor vehicle.

[0042] Naturally, it is possible that the powertrain is incorporated in a motor vehicle using one or more energy sources other than hydrogen.

[0043] The powertrain 1 includes an internal combustion engine 2 incorporating a combustion chamber and a fuel cell 3, both the internal combustion engine and the fuel cell using hydrogen as an energy source.

[0044] In the example shown, the powertrain 1 includes an electric motor 4 coupled to a storage battery 5, which in turn is coupled to the fuel cell 3.

[0045] The powertrain 1 is hybrid, so both the internal combustion engine 2 and the electric motor 4 of the hybrid powertrain 1 are rotationally coupled to a drive shaft 6 in order to propel the motor vehicle.

[0046] The fuel cell 3 includes a hydrogen inlet 7 and a hydrogen outlet 8, as well as an air inlet 9 and an air outlet 10.

[0047] The hydrogen inlet 7 and the hydrogen outlet 8 are advantageously an anode hydrogen inlet 7 and an anode hydrogen outlet 8 respectively, which are positioned in contact with the anode of the fuel cell 3.

[0048] The air inlet 9 and the air outlet 10 are advantageously a cathode air inlet 9 and a cathode air outlet 10 respectively, which are positioned in contact with the cathode of the fuel cell 3.

[0049] The fuel cell 3 generates an electric current and water from hydrogen and oxygen present in the air. The generated electric current can be used to power the storage battery 5, which in turn powers the electric motor 4.

[0050] Advantageously, the internal combustion engine 2 includes a hydrogen inlet 11, an air inlet 12 and an exhaust outlet 13.

[0051] Preferably, the powertrain 1 includes at least one storage tank 14 which is connected to the hydrogen inlet 7 of the fuel cell 3 and the hydrogen inlet 11 of the internal combustion engine 2 to supply hydrogen to them.

[0052] In the example shown, the three-way valve V3 allows the hydrogen from the storage tank 14 to selectively flow to the fuel cell 3 or the internal combustion engine 2.

[0053] The air introduced into the fuel cell 3 and the internal combustion engine can advantageously be the external air collected when the vehicle is in motion, which preferably passes through the air filter 15 upstream of the fuel cell 3 and the air filter 16 upstream of the internal combustion engine 2 respectively.

[0054] Preferably, a compressor 17 is arranged upstream of the air inlet 9 of the fuel cell 3.

[0055] Preferably, a turbo-compressor 18 is arranged upstream of the air inlet 12 of the internal combustion engine 2.

[0056] In addition, the powertrain includes a pipeline C1 which connects the air outlet 10 of the fuel cell 3 to the air inlet 12 of the internal combustion engine 2.

[0057] The shut-off valve V1 is positioned on the pipeline C1 to selectively allow the fluid present in the fuel cell 3 to flow from the air outlet 10 of the fuel cell 3 to the internal combustion engine 2.

[0058] Advantageously, an exhaust pipeline E can be arranged on the pipeline C1, upstream of the shut-off valve V1, to allow the air from the fuel cell 3 to escape.

[0059] In addition, the control device 19 is configured to cause the opening of the shut-off valve V1 when the fuel cell 3 and the internal combustion engine 2 have been shut down.

[0060] The control device 19 is also configured to operate the internal combustion engine 2, for example by means of an electric motor (such as the motor 4), without injecting hydrogen from the tank 14, in order to suck the fluid present in the fuel cell 3 towards the internal combustion engine 2.

[0061] As Figure 1 As shown, the powertrain 1 can include a recirculation unit 20 which is connected to the hydrogen outlet 8 and the hydrogen inlet 7 of the fuel cell 3.

[0062] The recirculation unit 20 advantageously incorporates a pump and allows the hydrogen not oxidized by the fuel cell 3 to be recirculated from the hydrogen outlet 8 towards the hydrogen inlet 7.

[0063] In the example shown, the pipeline C2 connects the hydrogen outlet 8 of the fuel cell 3 to the air inlet 12 of the internal combustion engine 2.

[0064] Furthermore, a shut-off valve V2 is arranged on the pipeline C2 and allows the fluid present in the fuel cell 3 to selectively flow from the hydrogen outlet 8 of the fuel cell 3 to the internal combustion engine 2.

[0065] The control device 19 is preferably configured to cause the opening of the shut-off valve V2 as well as the valve V1, and then operate the internal combustion engine 2 without injecting hydrogen.

[0066] Suction of fluid via the pipeline C2 and suction of fluid via the pipeline C1 allow for an increase in the efficiency of discharging water from the fluid present in the fuel cell 3.

[0067] In the example shown, the recirculation unit 20 is connected to the pipeline C2.

[0068] The pipeline C2 can be connected to the pipeline C1 upstream of the air inlet 12 of the internal combustion engine 2, such that the pipelines C1 and C2 form a common portion C3 that leads into the internal combustion engine 2 via the air inlet 12.

[0069] Preferably, the powertrain includes at least one condenser 21, which is positioned on the pipeline C1 and / or the pipeline C2.

[0070] In the example shown, the condenser is positioned on the common portion C3 downstream of the connection point of the pipelines C1 and C2.

[0071] The condenser 21 can help discharge the liquid water from the fluid sucked towards the internal combustion engine 2.

[0072] The present invention also relates to a method for managing the powertrain 1 as described above, and the method includes the following steps:

[0073] a) Cause the shutdown of the fuel cell 3;

[0074] b) Cause the shutdown of the internal combustion engine 2;

[0075] c) When the fuel cell 3 and the internal combustion engine 2 have been shut down, open the shut-off valve V1; and

[0076] d) When the shut-off valve V1 is open, operate the internal combustion engine 2 without injecting hydrogen from the storage tank 14 in order to suck the fluid present in the fuel cell 3 towards the internal combustion engine 2.

[0077] The internal combustion engine 2 thus acts as a vacuum pump to suck the fluid (especially air and water) present in the fuel cell 3 towards the combustion chamber of the internal combustion engine 2.

[0078] Thus, the management method according to the invention allows the fuel cell 3 to be dried after it has been shut down. In particular during restart, and especially when the outside temperature is negative, this drying allows a large amount of frozen water that could prevent its restart to be absent from the fuel cell 3. Thus, drying the fuel cell 3 facilitates restart and extends the service life of the fuel cell 3.

[0079] Steps a) and / or b) can be caused by the control device 19 in response to a command from the driver to switch off the motor vehicle.

[0080] Furthermore, steps a) and / or b) can be caused simultaneously or successively. Step b) can be carried out before step a), and vice versa.

[0081] Preferably, the opening of the valve V1 is caused by the control device 19.

[0082] In an embodiment, the powertrain 1 includes a recirculation unit 20.

[0083] Preferably, step c) includes opening the shut-off valve V2 as well as the valve V1, which can also be caused by the control device 19.

[0084] According to another feature, the operation of the internal combustion engine 2 in step d) can be maintained until the humidity level in the fuel cell 3 is less than or equal to a predetermined threshold.

[0085] The predetermined threshold can advantageously be a humidity level value that is considered low enough not to affect the operation of the fuel cell 3 during restart or its service life.

[0086] According to an alternative, the operation of the internal combustion engine 2 in step d) is maintained for a predetermined time interval. Thus, the costs associated with the installation of a humidity sensor for measuring the humidity level in the fuel cell 3 can be avoided.

[0087] This time interval is determined, for example, according to a predefined test, or can correspond to an estimated value of the time interval that allows the fuel cell 3 to be dried to a level considered dry enough.

[0088] As Figure 2 shown, the internal combustion engine 2 can be coupled to a turbo-compressor 18, which is positioned on the pipeline C1. The turbo-compressor 18 is thus arranged upstream of the air inlet 12 of the internal combustion engine 2 and downstream of the fuel cell 3.

[0089] In the example shown, the common portion C3 of the pipelines C1 and C2 is connected upstream of the air inlet of the turbo-compressor 18.

[0090] It can be stipulated that, in the absence of a common portion C3, each of the pipelines C1 and C2 is independently connected upstream of the air inlet of the turbo compressor 18.

[0091] In an embodiment, in addition to operating the internal combustion engine 2 in step d), the turbo compressor 18 can also be operated to provide more power to suck the fluid present in the fuel cell 3 towards the internal combustion engine 2.

[0092] In this regard, the control device 19 can be configured to cause the operation of the turbo compressor 18 in or after step d).

Claims

1. A method for managing a hybrid powertrain of a hydrogen motor vehicle, the hybrid powertrain including an internal combustion engine (2), a fuel cell (3), a hydrogen storage tank (14), and a line C1 that connects an air outlet (10) of the fuel cell (3) to an air inlet (12) of the internal combustion engine (2) and includes a shut-off valve V1, the method including the following steps: a) Cause the shutdown of the fuel cell (3); b) Cause the shutdown of the internal combustion engine (2); c) When the fuel cell (3) and the internal combustion engine (2) have been shut down, open the shut-off valve V1; And d) When the shut-off valve V1 is open, operate the internal combustion engine (2) without injecting hydrogen from the storage tank (14) so as to suck the fluid present in the fuel cell (3) towards the internal combustion engine (2) via the line C1.

2. The method according to claim 1, wherein The powertrain (1) includes a line C2 that connects a hydrogen outlet (8) of the fuel cell (3) to the air inlet (12) of the internal combustion engine (2) and includes a shut-off valve V2, and step c) includes opening the shut-off valve V2 and the valve V1 so as to also suck the fluid present in the fuel cell (3) towards the internal combustion engine (2) via the line C2 in step d).

3. The method according to claim 1 or 2, wherein Maintain the operation of the internal combustion engine (2) in step d) for a predetermined time interval.

4. The method according to claim 1 or 2, wherein Maintain the operation of the internal combustion engine (2) in step d) until the humidity level in the fuel cell (3) is less than or equal to a predetermined threshold.

5. A hybrid powertrain for a hydrogen motor vehicle, the hybrid powertrain including: An internal combustion engine (2); A fuel cell (3); A hydrogen storage tank (14); A line C1 that connects an air outlet (10) of the fuel cell (3) to an air inlet (12) of the internal combustion engine (2) and includes a shut-off valve V1 for selectively allowing the fluid present in the fuel cell (3) to flow from the air outlet (10) to the internal combustion engine (2); and A control device (19) configured to cause the opening of the shut-off valve V1 when the fuel cell (3) and the internal combustion engine (2) have been shut down and to operate the internal combustion engine (2) without injecting hydrogen from the tank (14) so as to suck the fluid present in the fuel cell (3) towards the internal combustion engine (2) via the line C1.

6. The powertrain according to claim 5, comprising a pipeline C2 that connects the hydrogen outlet (8) of the fuel cell (3) to the air inlet (12) of the internal combustion engine (2) and includes a shut-off valve V2 for selectively causing the fluid present in the fuel cell (3) to flow from said hydrogen outlet (8) to the internal combustion engine (2). The control device (19) is configured to cause the opening of the shut-off valve V2 and the valve V1, and then start the internal combustion engine (2) without injecting hydrogen, so as to also suck the fluid present in the fuel cell (3) towards the internal combustion engine (2) via the pipeline C2.

7. The powertrain according to claim 6, wherein, The powertrain (1) includes a recirculation unit (20) that is connected to the fuel cell (3) to recirculate hydrogen from the hydrogen outlet (8) towards the hydrogen inlet (7) of the fuel cell (3). The recirculation unit (20) is connected to the pipeline C2.

8. The powertrain according to claim 6 or 7, wherein, The pipeline C2 is connected to the pipeline C1 upstream of the air inlet (12) of the internal combustion engine (2).

9. The powertrain according to any one of claims 5 to 8, comprising at least one condenser (21) positioned on the pipeline C1 and / or the pipeline C2.

10. The powertrain according to any one of claims 5 to 9, wherein, The internal combustion engine (2) is coupled to a turbo-compressor (18) that is positioned on the pipeline C1, upstream of the air inlet (12) of the internal combustion engine (2) and downstream of the fuel cell (3).

11. A motor vehicle comprising the powertrain (1) according to any one of claims 5 to 10.

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