System and method for managing gas flow and heat flow at the outlet of a fuel cell to power a hydrogen heat engine or
By designing a gas management system, using electronic controllers and gas flow management devices, gas flow management of hydrogen thermal engines is optimized based on the gas flow temperature and concentration at the fuel cell outlet, the gas flow management of hydrogen thermal engines is solved in the prior art, and the problems of low efficiency and environmental pollution of fuel cell emission treatment in the prior art are achieved, and efficient fuel utilization and thermal management are achieved.
Patent Information
- Application Number
- CN202380088116.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-21
- Filing Date
- 2023-12-12
- Publication Date
- 2025-07-18
AI Technical Summary
There is a lack of effective systems and methods in the prior art to manage and control gas and heat flows at the outlets of fuel cells to optimize the supply of hydrogen thermal engines and operation of aftertreatment devices, resulting in environmental pollution and energy waste.
A gas management system is designed, including a gas flow management device and an electronic controller, which can selectively control the delivery path of the gas flow according to the gas flow temperature and concentration at the outlet of the fuel cell, and use excess hydrogen or oxygen for catalytic reduction or oxidation reactions to optimize the emission treatment of the fuel cell.
It realizes efficient utilization of fuel cell emissions, reduces fuel consumption, optimizes thermal management, improves the efficiency of aftertreatment devices, and complies with environmental protection regulations.
Smart Images
Figure CN120345084A_ABST
Abstract
Description
Technical field
[0001] The present invention relates to the use of integrating a fuel cell into the powertrain of a hydrogen thermal vehicle.
[0002] The present invention aims to propose a system and a method for managing the gas flow and heat flow at the outlet of a fuel cell to supply a thermal engine and / or its aftertreatment device. Background art
[0003] There are known vehicle traction systems that include a single hydrogen tank that can first supply a fuel cell, which in turn supplies electrical energy to a first electric motor, and the single hydrogen tank secondarily supplies a second hydrogen thermal engine so that both motors can be used to drive the vehicle forward.
[0004] The vehicle either operates using the hydrogen thermal engine (especially in the case of long-distance driving and high power requirements), or operates using the electric motor via the fuel cell (especially in the case of short-distance driving or low power requirements), or uses both motors simultaneously.
[0005] Since the internal combustion of hydrogen generates polluting gases and particles at the outlet of the thermal engine, these polluting gases and particles must be treated before being discharged into the atmosphere, so the vehicle is equipped with a device for post-treating these pollutants in order to comply with current regulations, such as European regulations known as "Euro 6d Full" or "Euro VI".
[0006] This aftertreatment device generally contains one or more catalytic converters and one or more particulate filters.
[0007] The catalytic element has a variable operating temperature window.
[0008] For example, a passive NOx adsorber (PNA) cold trap catalytic converter can store nitrogen oxides at a lower temperature (i.e., between 100°C and 200°C) and release nitrogen oxides when the temperature exceeds this value.
[0009] A second tandem nitrogen oxide treatment system (such as a lean NOx trap (LNT) or a selective catalytic reducer (SCR)) can be used in combination to treat nitrogen oxide emissions released at gas temperatures of 200°C and above. The nitrogen oxides are reduced to non-polluting gases emitted from the exhaust, especially nitrogen.
[0010] In a proton exchange membrane fuel cell (PEMFC) operating above 160°C, hot gases are discharged at the outlet of the cell, and these gases still contain hydrogen from the anode of the cell and oxygen-depleted air from the cathode of the cell.
[0011] These gas flows are typically released directly into the atmosphere, which is harmful to the environment and not optimal.
[0012] Thus, a particular problem of the present invention relates to optimizing the heat flows generated by these two systems and the use of hydrogen and compressed air, by using the gases discharged from the fuel cell to directly supply a hydrogen thermal engine and / or activate the pollution control system of the hydrogen thermal engine.
[0013] There is no device in the prior art for controlling and managing various heat flows and energy flows to achieve post-treatment of gas emissions using the hot hydrogen or hot oxygen discharged from the fuel cell. Summary of the Invention
[0014] The present invention aims to overcome at least some of the foregoing disadvantages and proposes a system that can have performance advantages in terms of characteristics, energy efficiency, simplicity of implementation, and reliability.
[0015] In view of the foregoing, the present invention relates to a gas management system in a hydrogen hybrid vehicle, the gas management system including an electric motor and a hydrogen internal combustion thermal engine, a fuel cell for supplying electrical energy to the electric motor, a hydrogen tank for supplying hydrogen to the battery and the thermal engine, a post-treatment device designed to process the exhaust gas at the outlet of the thermal engine, characterized in that the gas management system includes gas flow management devices and an electronic controller, the gas flow management devices being capable of selectively delivering a gas flow from the fuel cell to the post-treatment device and / or to the internal combustion engine, and / or from the hydrogen tank to the fuel cell and / or to the internal combustion engine, the electronic controller being configured to control the gas flow management devices according to the temperature of a first gas flow and / or a second gas flow discharged at the outlet of the fuel cell.
[0016] In one embodiment, the first gas flow discharged at the outlet of the fuel cell contains hydrogen, and the system further includes a sensor for determining the temperature of this first flow, and the gas flow management devices include a first valve and a second valve, the first valve being designed to deliver a hydrogen flow from the hydrogen tank to the fuel cell and / or to the internal combustion engine, the second valve being designed to deliver a first hydrogen-containing flow from the fuel cell to the thermal engine and / or to the post-treatment device. The electronic controller is configured to control the opening and closing of the first valve and / or the second valve according to the temperature of the first gas flow.
[0017] For example, the post-treatment device further includes a catalytic converter capable of processing nitrogen oxides from the internal combustion engine, the system further includes a sensor for determining the concentration of nitrogen oxides in the catalytic converter, and the electronic controller is configured to control the opening and closing of the first valve and / or the second valve according to the concentration of nitrogen oxides in the catalytic converter.
[0018] The invention also relates to a method for implementing the system defined above, the method comprising the following steps:
[0019] - A first step, in which the temperature of the first gas stream discharged at the outlet of the fuel cell is compared with a first threshold value,
[0020] - If the first threshold value is exceeded in the first step, a second step is carried out, in which the measured concentration of nitrogen oxides in the catalytic converter is compared with a second threshold value,
[0021] - If the second threshold value is exceeded during the second step, a third step is carried out, in which the computer controls the second valve to convey the hydrogen-containing stream from the fuel cell to the catalytic converter,
[0022] - After the third step, a fourth step is carried out, in which the hydrogen gas conveyed to the catalytic converter in the third step is used as a reactant for the reduction reaction with the nitrogen oxides present in the catalytic converter until the concentration of nitrogen oxides in the catalytic converter drops below the second threshold value,
[0023] - If the first threshold value is not exceeded during the first step, a fifth step is carried out, in which the computer controls the second valve to convey a first hydrogen-containing gas stream from the fuel cell to the heat engine.
[0024] Preferably, the second gas stream discharged at the outlet of the fuel cell contains oxygen, and the system further comprises a sensor for determining the temperature of this second gas stream. These gas stream management devices include a third valve and a fourth valve. The third valve is designed to convey the second oxygen-containing gas stream from the fuel cell to the particulate filter, and the fourth valve is designed to convey the second oxygen-containing gas stream from the fuel cell to the internal combustion engine. The electronic controller is capable of controlling the opening and closing of the third valve and / or the fourth valve according to the temperature of the second gas stream.
[0025] In an embodiment of the system, the post-treatment device includes a particulate filter capable of trapping nitrogen oxides from the heat engine. The system further includes a sensor for determining the oxygen concentration of the second gas stream. The electronic controller is configured to control the opening and closing of the third valve and / or the fourth valve according to the oxygen concentration of the second gas stream.
[0026] The invention also relates to a method for implementing the system, the method comprising the following steps:
[0027] - The first step, in which the temperature of the second gas stream discharged at the outlet of the fuel cell is also compared with a third threshold value.
[0028] - If the third threshold value is exceeded in the first step, a sixth step is carried out, in which the oxygen concentration of the second gas stream at the outlet of the fuel cell is compared with a fourth threshold value.
[0029] - If the fourth threshold value is not exceeded in the sixth step, a seventh step is carried out, in which the computer controls the third valve to convey the second oxygen-containing gas stream from the fuel cell to the particulate filter.
[0030] - Immediately following the seventh step, an eighth step is carried out, in which the oxygen conveyed to the particulate filter in the seventh step is used as a reactant for the oxidation reaction with the nitrogen oxides present in the particulate filter until the concentration of the nitrogen oxides in the particulate filter drops below the fourth threshold value.
[0031] - If the oxygen concentration exceeds the fourth threshold value in the sixth step, a ninth step is carried out, in which the computer controls the fourth valve to convey the second oxygen-containing gas stream from the fuel cell to the heat engine.
[0032] Preferably, in the first step, the following operations are carried out simultaneously: comparing the temperature of the first hydrogen-containing gas stream discharged at the outlet of the fuel cell with the first threshold value and comparing the temperature of the second oxygen-containing gas stream discharged at the outlet of the fuel cell with the third threshold value. If the first threshold value is exceeded, the first step proceeds to the second step on the one hand, and if the third threshold value is exceeded, the first step proceeds to the sixth step on the other hand.
[0033] The invention also relates to a vehicle comprising the aforementioned system for implementing the method as defined above. Description of the Drawings
[0034] The invention will be better understood by studying carefully the embodiments provided by way of non-limiting example and shown in the drawings, in which:
[0035] Figure 1 is a schematic diagram of the architecture of the gas management system according to the invention.
[0036] Figure 2 shows the steps of the method implemented by the system. Detailed Description
[0037] Figure 1 Shows a system according to the present invention, which relates to a gas management system 1 in a hydrogen hybrid vehicle.
[0038] System 1 includes an electric motor 2 and a hydrogen internal combustion heat engine 3, a fuel cell 4 for supplying electrical energy to the motor 2, a hydrogen gas tank 5 for supplying hydrogen gas to the cell 4 and the heat engine 3, and a post-treatment device 6 designed to treat the exhaust gas at the outlet of the heat engine 3.
[0039] System 1 includes gas flow management devices 16, 17, 18, 19.
[0040] The management devices 16, 17, 18, 19 are capable of selectively delivering the gas flow from the fuel cell 4 to the post-treatment device 6 and / or to the heat engine 3, and / or from the hydrogen gas tank 5 to the fuel cell 4 and / or to the heat engine 3.
[0041] The system further includes an electronic controller 15, which is configured to control the management devices 16, 17, 18, 19 according to the temperature of the first gas flow and / or the second gas flow discharged at the outlet of the fuel cell 4.
[0042] The temperature of the hot gas discharged from the fuel cell is greater than or equal to substantially 160 °C.
[0043] The first gas flow discharged at the outlet of the fuel cell 4 contains, for example, hydrogen.
[0044] In this case, system 1 may further include a sensor for determining the temperature of this first gas flow.
[0045] System 1 may further include a catalytic converter 7 capable of treating nitrogen oxides from the heat engine 3.
[0046] The catalytic converter 7 is connected to the post-treatment device 6 and is, for example, a PNA or LNT catalytic converter.
[0047] The gas flow management devices 16, 17, 18, 19 thus further include a first valve 16 and a second valve 17, the first valve being designed to deliver a hydrogen gas flow from the hydrogen gas tank 5 to the fuel cell 4 and / or to the heat engine 3, the second valve being designed to deliver the first hydrogen-containing gas flow from the fuel cell 4 to the heat engine 3 and / or to the post-treatment device 6, and the electronic controller 15 being configured to control the opening and closing of the first valve 16 and / or the second valve 17 according to the temperature of the first gas flow.
[0048] The gas flow management devices 16, 17, 18, 19 may further include an air filter 9, an air compressor 10, a pump 15, and a silencer 20 connected to the pump 15. The air filter and the air compressor are connected to an intake port 11, a cooler 13, and a humidifier 15 for this air. The pump and the silencer are connected to a fluid distribution network in the vehicle and are optionally controlled by a controller 15.
[0049] The after-treatment device (6) further includes a catalytic converter (7) capable of treating nitrogen oxides from the thermal engine 3. The system 1 may further include a sensor for determining the concentration of nitrogen oxides in the catalytic converter 7.
[0050] The electronic controller 15 is then configured to control the opening and closing of the first valve and / or the second valve according to the concentration of nitrogen oxides in the catalytic converter 7.
[0051] With this system 1, when a vehicle including the system 1 is driven partially or completely by the operation of a fuel cell 4 (where hydrogen is consumed at the anode of the cell 4), the excess hydrogen found at the outlet of the cell 4 can be reused.
[0052] Figure 2 A method for implementing the system as described above is shown, where the hot gas includes hydrogen.
[0053] The method includes the following steps:
[0054] - A first step E1, in which the temperature of a first gas flow discharged at the outlet of the fuel cell 4 is compared with a first threshold.
[0055] - If the first threshold is exceeded in the first step E1, a second step E2 is carried out, in which the measured concentration of nitrogen oxides in the catalytic converter 7 is compared with a second threshold.
[0056] - If the second threshold is exceeded during the second step E2, a third step E3 is carried out, in which the computer 15 controls the second valve 17 to deliver a hydrogen-containing flow from the fuel cell 4 to the catalytic converter 7.
[0057] - After the third step E3, a fourth step E4 is carried out, in which the hydrogen delivered to the catalytic converter 7 in the third step E3 is used as a reactant for the reduction reaction with the nitrogen oxides present in the catalytic converter 7 until the concentration of nitrogen oxides in the catalytic converter 7 drops below the second threshold.
[0058] - If the first threshold is not exceeded during the first step E1, a fifth step E2 is carried out, in which the computer 15 controls the second valve 17 to deliver a first hydrogen-containing gas flow from the fuel cell 4 to the thermal engine 3.
[0059] This method enables the detection and optimal use of the excess hydrogen at the outlet of the fuel cell 4, which cannot be achieved by any system in the prior art.
[0060] In fact, on the one hand, if the storage of nitrogen oxides in the catalytic converter 7 for trapping nitrogen oxides requires entering the reduction stage, the hydrogen discharged from the anode of the cell can then be used to reduce these nitrogen oxides at high temperature.
[0061] On the other hand, if the nitrogen oxides in the catalytic converter 7 for trapping nitrogen oxides do not need to be reduced, the hydrogen discharged from the anode can be injected as fuel into the combustion chamber of the hydrogen thermal engine 2, and then a new combustion cycle can occur.
[0062] According to one embodiment, the second gas stream discharged at the outlet of the fuel cell 4 contains oxygen as a supplement or alternative to the discharged hydrogen, and the system 1 and the method are different.
[0063] In fact, when the vehicle including the system 1 is partially or fully driven by the operation of the fuel cell 4, there may be excess oxygen at the outlet of the cell 4.
[0064] The system 1 can also be used to optimize the management of this oxygen.
[0065] If the second gas stream discharged at the outlet of the fuel cell 4 includes oxygen, the system 1 further includes a sensor for determining the temperature of this second gas stream.
[0066] In addition, the gas stream management devices 16, 17, 18, 19 include a third valve 18 and a fourth valve 19. The third valve is designed to convey the second oxygen-containing gas stream from the fuel cell 4 to the particulate filter 8, and the fourth valve is designed to direct the oxygen stream from the fuel cell 4 to the thermal engine 3. The electronic controller 15 can control the opening and closing of the third valve 18 and / or the fourth valve 19 according to the temperature of the second gas stream.
[0067] The aftertreatment device 6 includes a particulate filter 8 capable of trapping nitrogen oxides from the thermal engine 3. A sensor can also be provided to determine the oxygen concentration of the second gas stream. The electronic controller 15 is configured to control the opening and closing of the third valve 18 and / or the fourth valve 19 according to the oxygen concentration of the second gas stream.
[0068] This provides a system that enables the oxygen discharged from the cathode of the cell 4 to be used to oxidize these particles at high temperature if the oxidation stage is required for storing the particles in the particulate filter 6 in the exhaust pipeline of the thermal engine 2.
[0069] On the other hand, if it is not necessary to store the particles in the particulate filter 6 of the exhaust line of the heat engine 2 and it is envisaged that a lean mixture will occur in the combustion chamber (i.e., the air at the outlet of the battery 4 has a low oxygen content because part of the oxygen has been consumed), the oxygen discharged by the cathode can be injected as an oxidant and a new combustion cycle can occur.
[0070] In this case, if the hot gas discharged at the outlet of the fuel cell 4 contains oxygen, the method comprises the following steps:
[0071] - A first step E1, in which the temperature of the second gas stream discharged at the outlet of the fuel cell 4 is also compared with a third threshold value,
[0072] - If the third threshold value is exceeded in the first step E1, a sixth step E6 is carried out, in which the oxygen concentration of the second gas stream at the outlet of the fuel cell 4 is compared with a fourth threshold value,
[0073] - If the fourth threshold value is not exceeded in the sixth step E6, a seventh step E7 is carried out, in which the computer 15 controls the third valve 18 to convey the second oxygen-containing gas stream from the fuel cell 4 to the particulate filter 8,
[0074] - Immediately following the seventh step E7, an eighth step E8 is carried out, in which the oxygen conveyed to the particulate filter 8 in the seventh step E7 is used as a reactant for the oxidation reaction with the nitrogen oxides present in the particulate filter 8 until the concentration of the nitrogen oxides in the particulate filter 8 drops below the fourth threshold value,
[0075] - If the oxygen concentration exceeds the fourth threshold value in the sixth step E6, a ninth step E9 is carried out, in which the computer 15 controls the fourth valve 19 to convey the second oxygen-containing gas stream from the fuel cell 4 to the heat engine 3.
[0076] If the hot gas discharged at the outlet of the fuel cell 4 contains hydrogen, the method is compatible with the above method.
[0077] In fact, if the hot gas discharged at the outlet of the fuel cell 4 contains both hydrogen and oxygen, the system 1 can also operate.
[0078] The gas flow management devices 16, 17, 18, 19 may thus comprise a first valve 16, a second valve 17, a third valve 18 and a fourth valve 19, and the electronic controller 15 is configured to control said valves.
[0079] Preferably, such a system is implemented by a method that combines the method described above for evaluating the temperature of the hot gas discharged at the outlet of the fuel cell 4, and in a first step E1, the following operations are performed simultaneously: comparing the temperature of the first hydrogen-containing gas stream discharged at the outlet of the fuel cell 4 with a first threshold; comparing the temperature of the second oxygen-containing gas stream discharged at the outlet of the fuel cell 4 with the first threshold; and comparing the temperature of the oxygen in the hot gas discharged at the outlet of the fuel cell 4 with a third threshold.
[0080] If the first threshold is exceeded, the first step E1 proceeds to the second step E2 on the one hand, and if the third threshold is exceeded, the first step proceeds to the sixth step E6 on the other hand.
[0081] The invention also relates to a vehicle, in particular a motor vehicle, comprising the aforementioned system for implementing the described method.
[0082] This provides a solution that implements a strategy for managing the outlet flow from the fuel cell 4 to the hydrogen thermal engine 2 and / or its aftertreatment system 6, thereby significantly limiting the consumption of hydrogen as a fuel and the consumption of compressed oxygen as an oxidant, optimizing their use and improving the thermal management of these two systems.
Claims
1. A gas management system (1) in a hydrogen hybrid vehicle, the gas management system comprising an electric motor (2) and a hydrogen internal combustion heat engine (3), a fuel cell (4) for supplying electrical energy to the electric motor (2), a hydrogen tank (5) for supplying hydrogen to the fuel cell (4) and the heat engine (3), and a post-treatment device (6) designed to treat the exhaust gas at the outlet of the heat engine (3), characterized in that, The gas management system includes gas flow management devices (16, 17, 18, 19) and an electronic controller (15). These gas flow management devices can selectively transport the gas flow from the fuel cell (4) to the post-treatment device (6) and / or to the thermal engine (3), and / or from the hydrogen tank (5) to the fuel cell (4) and / or to the thermal engine (3). The electronic controller is configured to control these gas flow management devices (16, 17, 18, 19) according to the temperature of the first gas flow and / or the second gas flow discharged at the outlet of the fuel cell (4).
2. The system (1) according to claim 1, wherein, The first gas flow discharged at the outlet of the fuel cell (4) contains hydrogen. The system (1) further includes a sensor for determining the temperature of this first flow. These gas flow management devices (16, 17, 18, 19) include a first valve (16) and a second valve (17). The first valve is designed to transport the hydrogen flow from the hydrogen tank (5) to the fuel cell (4) and / or to the thermal engine (3). The second valve is designed to transport the first hydrogen-containing flow from the fuel cell (4) to the thermal engine (3) and / or to the post-treatment device (6). The electronic controller (15) is configured to control the opening and closing of the first and / or second valves (16, 17) according to the temperature of the first gas flow.
3. The system (1) according to claim 2, wherein the post-treatment device (6) further includes a catalytic converter (7) that can process nitrogen oxides from the thermal engine (3). The system further includes a sensor for determining the concentration of nitrogen oxides in the catalytic converter (7), and the electronic controller (15) is configured to control the opening and closing of the first and / or second valves (16, 17) according to the concentration of nitrogen oxides in the catalytic converter (7).
4. A method for implementing the system (1) according to any one of claims 2 and 3, the method comprising the following steps: - A first step (E1), in which the temperature of the first gas flow discharged at the outlet of the fuel cell (4) is compared with a first threshold value. - If the first threshold value is exceeded in the first step (E1), then a second step (E2) is performed. In the second step, the measured concentration of nitrogen oxides in the catalytic converter (7) is compared with a second threshold value. - If the second threshold value is exceeded during the second step (E2), then a third step (E3) is performed. In the third step, the computer (15) controls the second valve (17) to transport the hydrogen-containing flow from the fuel cell (4) to the catalytic converter (7). - After the third step (E3), a fourth step (E4) is performed. In the fourth step, the hydrogen transported to the catalytic converter (7) in the third step (E3) is used as a reactant for the reduction reaction with the nitrogen oxides present in the catalytic converter (7) until the concentration of nitrogen oxides in the catalytic converter (7) drops below the second threshold value. - If the first threshold is not exceeded during this first step (E1), a fifth step (E2) is carried out, in which the computer (15) controls the second valve (17) to convey the first hydrogen-containing gas stream from the fuel cell (4) to the heat engine (3).
5. The system (1) according to any one of claims 1 to 3, wherein, The second gas stream discharged at the outlet of the fuel cell (4) contains oxygen. The system (1) further includes a sensor for determining the temperature of this second gas stream. These gas stream management devices (16, 17, 18, 19) include a third valve (18) and a fourth valve (19). The third valve is designed to convey the second oxygen-containing gas stream from the fuel cell (4) to the particulate filter (8). The fourth valve is designed to convey the second oxygen-containing gas stream from the fuel cell (4) to the heat engine (3). The electronic controller (15) is capable of controlling the opening and closing of the third and / or fourth valves (18, 19) according to the temperature of the second gas stream.
6. The system (1) according to claim 5, wherein the after-treatment device (6) includes a particulate filter (8) capable of trapping nitrogen oxides from the heat engine (3). The system further includes a sensor for determining the oxygen concentration of the second gas stream. The electronic controller (15) is configured to control the opening and closing of the third and / or fourth valves (18, 19) according to the oxygen concentration of the second gas stream.
7. A method for implementing the system (1) according to any one of claims 5 and 6, the method comprising the following steps: - A first step (E1), in which the temperature of the second gas stream discharged at the outlet of the fuel cell (4) is also compared with a third threshold. - If the third threshold is exceeded in the first step (E1), a sixth step (E6) is carried out, in which the oxygen concentration of the second gas stream at the outlet of the fuel cell (4) is compared with a fourth threshold. - If the fourth threshold is not exceeded in the sixth step (E6), a seventh step (E7) is carried out, in which the computer (15) controls the third valve (18) to convey the second oxygen-containing gas stream from the fuel cell (4) to the particulate filter (8). - Immediately following the seventh step (E7), an eighth step (E8) is carried out, in which the oxygen conveyed to the particulate filter (8) in the seventh step (E7) is used as a reactant for the oxidation reaction with the nitrogen oxides present in the particulate filter (8) until the concentration of nitrogen oxides in the particulate filter (8) drops below the fourth threshold. - If the oxygen concentration exceeds the fourth threshold in the sixth step (E6), a ninth step (E9) is carried out, in which the computer (15) controls the fourth valve (19) to convey the second oxygen-containing gas stream from the fuel cell (4) to the heat engine (3).
8. The method according to claim 5, wherein, In this first step (E1), the following operations are carried out simultaneously: comparing the temperature of the first hydrogen-containing gas stream discharged at the outlet of the fuel cell (4) with the first threshold value and comparing the temperature of the second oxygen-containing gas stream discharged at the outlet of the fuel cell (4) with the third threshold value. If the first threshold value is exceeded, the first step (E1) proceeds on the one hand to the second step (E2), and if the third threshold value is exceeded, the first step proceeds on the other hand to the sixth step (E6).
9. A vehicle comprising a system (1) as claimed in any one of claims 1 to 4 and 6 to 7, the system being for implementing a method as claimed in any one of claims 5 and 9.