Method for controlling a hydrogen hybrid powertrain

Abstract

Method for controlling a hybrid hydrogen powertrain (1) for a motor vehicle comprising: a hydrogen tank (17); a hydrogen internal combustion engine (3) powered by the tank (17), adapted to drive a transmission shaft (7), said engine (3) producing hot exhaust gases; a fuel cell (9) powered by the hydrogen tank (17) and an electric motor (5) powered by the fuel cell (9), said electric motor (5) being coupled to the transmission shaft (7) of the motor vehicle; the method being characterized in that the hot exhaust gases are guided towards the fuel cell (9) to bring the temperature of the fuel cell (9) to a determined operating temperature. Abstract figure: Figure 1

Description

Title of the invention: Method for controlling a hydrogen hybrid powertrain

[0001] The invention relates to a method for controlling a hydrogen hybrid powertrain comprising a hydrogen internal combustion engine and a hydrogen fuel cell adapted to power an electric motor.

[0002] The invention further relates to the hydrogen hybrid powertrain controlled by the method.

[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 hybrid powertrain comprising a hydrogen internal combustion engine and an electric motor powered by a hydrogen fuel cell. These vehicles can then operate with hydrogen stored in the vehicle in the form of a pressurized bottle or in liquid form in a tank, for example.

[0005] One way to improve such a hybrid system and in particular to improve the performance of the fuel cell at start-up is to increase the temperature of the fuel cell. Indeed, to reach its optimal performance more quickly, the cell must often be warmed up at start-up, in particular when the outside temperatures are negative.

[0006] Patent application US6588211 thus presents a vehicle comprising an internal combustion engine connected to a transmission shaft for driving the vehicle as well as a fuel cell supplying a battery adapted to supply energy to the electrical devices present in the vehicle. It describes in particular a gas generation system thermally coupled to the exhaust gas line of the engine so that the gas of the gas generation system is heated by the exhaust gas. The gas generation system then makes it possible to preheat the exhaust gas catalyst of the engine or the battery system in a short time when necessary.

[0007] However, this configuration is complex and cumbersome. In addition, the system does not does not allow the temperature to be regulated, which can lead to overheating of the fuel cell or even insufficient heating of the fuel cell.

[0008] Thus, there is a need for a hybrid powertrain having a control method for improving its performance.

[0009] For this purpose, a method is proposed for controlling a hydrogen hybrid powertrain for a motor vehicle comprising:

[0010] a hydrogen tank;

[0011] a hydrogen internal combustion engine powered by the tank, adapted to drive a transmission shaft, said engine producing hot exhaust gases;

[0012] a fuel cell powered by the hydrogen tank and an electric motor powered by the fuel cell, said electric motor being coupled to the transmission shaft of the motor vehicle. And according to the invention, the hot exhaust gases are guided towards the fuel cell to bring the temperature of the fuel cell to a determined operating temperature.

[0013] Thus, one of the characteristics of the invention lies in the direct use of the hot exhaust gases produced by the internal combustion engine to increase the temperature of the cell to a determined operating temperature.

[0014] This configuration allows a simplified method to be implemented for increasing the temperature of the fuel cell since the exhaust gases are used directly. This method also does not require the use of additional fluids to carry out the heat exchange.

[0015] In addition, this method makes it possible to avoid the use of additional energy to increase the temperature of the cell since the hot exhaust gases are produced by the internal combustion engine.

[0016] Advantageously, the temperature of the fuel cell is measured by a temperature measuring device, and the hot exhaust gases are guided towards the fuel cell as long as the measured cell temperature is lower than the determined operating temperature.

[0017] Measuring the temperature of the fuel cell thus allows the user to know the temperature of the cell, and above all, depending on the control method, to guide the exhaust gases towards the fuel cell until the determined operating temperature is reached.

[0018] Preferably, a three-way valve connected to the internal combustion engine is used to recover the hot exhaust gases and to guide the hot exhaust gases towards the fuel cell and towards the outside.

[0019] The use of the three-way valve then makes it possible to guide the hot exhaust gases either towards the outside of the engine and therefore the vehicle or towards the fuel cell. fuel. Gas guidance is also simplified in that it is sufficient to control the rotation of the valve shaft.

[0020] The use of the three-way valve also makes it possible to partially open the channels, in particular the one towards the fuel cell, in order to adapt the flow rate of the hot exhaust gases and therefore to influence the heating of the cell.

[0021] Advantageously, the three-way valve is coupled to the temperature measuring device.

[0022] Coupling the three-way valve with the temperature measuring device enables the control method to automatically guide the hot exhaust gases according to the temperature of the fuel cell.

[0023] The method thus controls the three-way valve as a function of the temperature of the cell to avoid overheating thereof by increasing the temperature of the cell beyond what is necessary, but also to avoid an insufficient increase in the temperature of the cell by not sufficiently increasing its temperature.

[0024] The invention also relates to a hydrogen hybrid powertrain of a motor vehicle comprising:

[0025] a hydrogen tank;

[0026] a hydrogen internal combustion engine powered by the tank, adapted to drive a transmission shaft and, said engine producing hot exhaust gases;

[0027] a fuel cell powered by the hydrogen tank; and,

[0028] an electric motor powered by the fuel cell, said electric motor being coupled to the transmission shaft. The motor comprises a circuit for guiding hot exhaust gases towards the fuel cell to bring the temperature of the fuel cell to a determined operating temperature.

[0029] The hybrid powertrain described is notably implemented by the control method thus making it possible to automate the heating of the fuel cell.

[0030] Advantageously, the hybrid powertrain comprises a device for measuring the temperature of the fuel cell.

[0031] Preferably, the guide circuit comprises a three-way valve connected to the internal combustion engine to recover the hot exhaust gases and to guide the hot exhaust gases towards the fuel cell and towards the outside.

[0032] Advantageously, the three-way valve is coupled to the temperature measuring device.

[0033] The invention further relates to a motor vehicle comprising a hydrogen hybrid powertrain as described above, controlled by the control method described above.

[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 following figures:

[0035] [Fig. 1] is a diagram showing a hybrid powertrain according to the invention.

[0036] [Fig.2] is a diagram showing an element of the hybrid powertrain as described in another embodiment of the invention.

[0037] [Fig.l] shows a hybrid hydrogen powertrain 1 on board a motor vehicle controlled by the control method according to the invention.

[0038] The hybrid powertrain 1 comprises an internal combustion engine 3 and an electric motor 5. The combustion engine 3 and the electric motor 5 are connected to a drive shaft 7 connected to the wheels for driving the vehicle.

[0039] The internal combustion engine 3 operates using hydrogen. The electric motor 5, for its part, is powered by a fuel cell 9 operating with hydrogen as well as a buffer battery 11.

[0040] Indeed, the fuel cell 9 generates a direct current which will be converted by a DC / DC converter 13. The current generated by the fuel cell 9 makes it possible to power the electric motor 5 but also to power the auxiliary electrical circuits adapted to operate the various accessories of the vehicle.

[0041] However, when the fuel cell 9 is not operating, the ancillary electrical circuits are not supplied with electrical energy, so a buffer battery 11 is used to produce sufficient energy for their operation. In addition, when the fuel cell 9 starts operating, the buffer battery 11 makes it possible to supply sufficient electrical energy for its operation from the start.

[0042] The fuel cell 9 is installed in a casing 41 which may be made of aluminum or plastic for example to ensure sealing and protect the fuel cell 9.

[0043] Before reaching the electric motor 5, the electrical energy is also converted by a DC / AC converter 15.

[0044] The fuel cell 9 and the internal combustion engine 3 are powered by hydrogen from a hydrogen tank 17. The hydrogen used here corresponds to dihydrogen H2. The tank 17 comprises an interface for its filling, not shown, as well as an outlet connected to a supply circuit 19.

[0045] Hydrogen can for example be stored in liquid form.

[0046] The hydrogen supply circuit 19 is common to the fuel cell 9 and to the internal combustion engine 3.

[0047] The internal combustion engine 3 further generates hot exhaust gases during the combustion reaction. In fact, during the combustion reaction, hydrogen reacts with oxygen. For this purpose, air is taken from outside the vehicle and is then guided to the combustion engine 3 by a circuit air supply 21. The exhaust gases thus include water produced during the reaction and any components already present in the air taken in such as nitrogen.

[0048] The air supply circuit 21 comprises a filter 23 to prevent the presence of particles in the air supply circuit 21 as well as in the combustion engine 3. The air supply circuit 21 further comprises a compressor 25 and a cooler 27 of the air before guiding it into the combustion engine 3.

[0049] The hot exhaust gases leaving the combustion engine 3 are then guided by a guide circuit 29 either towards the air outlet 31, or exhaust pipe, of the vehicle or towards the fuel cell 5.

[0050] For this, the guide circuit 29 comprises a three-way valve 33, connected to the internal combustion engine 3 by a first pipe 35, to the fuel cell 5 by a second pipe 37 and to the air outlet 31 by a third pipe 39 leading to the outside.

[0051] The three-way valve 33 thus makes it possible to direct the exhaust gases into the desired pipe but also to block access to a pipe as desired. For this, the three-way valve comprises a valve shaft (not shown in the figures) controlled by the guidance method. The valve shaft has a part adapted to obstruct one or more pipes in part or completely depending on its orientation.

[0052] The valve can also guide the hot exhaust gases simultaneously to the fuel cell 9 and to the air outlet 31.

[0053] The hot exhaust gases are conveyed from the valve 33 to the fuel cell 9 via the second pipe 37.

[0054] Once conveyed to the fuel cell 9, the exhaust gases are injected into the casing 41 of the fuel cell 9.

[0055] In another embodiment, with reference to [Fig.2], the casing 41 has a first 43 and a second 45 compartment. The fuel cell 9 is installed in the first compartment 43 while the hot exhaust gases are injected and guided into the second compartment 45.

[0056] The first 43 and second 45 compartments are separated by a wall 49 at which the heat exchange is carried out between the hot exhaust gases and the fuel cell 9 to increase its temperature.

[0057] The second compartment 45 may, for example, comprise inside a conduit (not shown in the figure) taking the form of a coil or fin to optimize the heat exchange.

[0058] Once removed from the fuel cell housing 41, the cooled exhaust gases are guided by a pipe 47 to the second pipe 37 to be evacuated through the air outlet 31.

[0059] The hybrid powertrain 1 may also comprise a temperature measuring device (not shown in the figures) installed at the fuel cell 9 to measure its temperature. This device may for example be a bimetallic thermometer.

[0060] The three-way valve 33 can be coupled to the temperature measuring device so that it can be controlled as a function of the temperature of the fuel cell 9.

[0061] The control method according to the invention thus makes it possible to control the hybrid powertrain 1 so as to guide the hot exhaust gases towards the fuel cell 9 to bring the temperature of the fuel cell 9 to a determined operating temperature.

[0062] The temperature of the battery 9 being measured by the measuring device described above.

[0063] The operating temperature of the battery can be determined based on the characteristics of the battery for example.

[0064] The operating temperature may be at least 10°C. Preferably it is between 60°C and 80°C.

[0065] Alternatively, the control method will also, depending on the temperature measured in the fuel cell 9, control the three-way valve to guide the hot exhaust gases towards the cell 9. Indeed, if the measured temperature of the cell is lower than the determined operating temperature then the method controls the three-way valve so that the hot exhaust gases are directed towards the cell.

[0066] In the case where the measured temperature of the cell is higher than the determined operating temperature then the method controls the three-way valve so as to direct the hot exhaust gases to the outside.

[0067] Alternatively, the method may also control to guide only a portion of the hot exhaust gases to the stack based on the measured temperature.

Claims

Claims

1. Method for controlling a hybrid hydrogen powertrain (1) for a motor vehicle comprising: a hydrogen tank (17); a hydrogen internal combustion engine (3) powered by the tank (17), adapted to drive a transmission shaft (7), said engine (3) producing hot exhaust gases; a fuel cell (9) powered by the hydrogen tank (17) and an electric motor (5) powered by the fuel cell (9), said electric motor (5) being coupled to the transmission shaft (7) of the motor vehicle; the method being characterized in that the hot exhaust gases are guided towards the fuel cell (9) to bring the temperature of the fuel cell (9) to a determined operating temperature.

2. Control method according to claim 1, characterized in that: the temperature of the fuel cell (9) is measured by a temperature measuring device; and, the hot exhaust gases are guided towards the fuel cell as long as the measured cell temperature is lower than the determined operating temperature.

3. Control method according to claim 2, characterized in that a three-way valve (33) connected to the internal combustion engine (3) is used to recover the hot exhaust gases and to guide the hot exhaust gases to the fuel cell (9) and to the outside (31).

4. Control method according to claim 3, characterized in that the three-way valve (33) is coupled to the temperature measuring device.

5. A hybrid hydrogen powertrain (1) of a motor vehicle comprising: a hydrogen tank (17); a hydrogen internal combustion engine (3) powered by the tank (17), adapted to drive a transmission shaft (7) and, said engine (2) producing hot exhaust gases; a fuel cell (9) powered by the hydrogen tank (17); and, an electric motor (5) powered by the fuel cell (9), said electric motor (5) being coupled to the transmission shaft (7); characterized in that it comprises a guide circuit (29) for the hot exhaust gases towards the fuel cell (9) to bring the temperature of the fuel cell (9) to a determined operating temperature.

6. Hybrid hydrogen powertrain (1) according to claim 5, characterized in that it comprises a device for measuring the temperature of the fuel cell (9).

7. A hydrogen hybrid powertrain (1) according to claim 6, characterized in that the guide circuit (29) comprises a three-way valve (33) connected to the internal combustion engine (3) for recovering the hot exhaust gases and for guiding the hot exhaust gases to the fuel cell (9) and to the outside.

8. A hydrogen hybrid powertrain (1) according to claim 7, characterized in that the three-way valve (33) is coupled to the temperature measuring device.

9. A motor vehicle comprising a hydrogen hybrid powertrain (1) according to any one of claims 5 to 8 controlled by the control method according to any one of claims 1 to 4.

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