SYSTEM AND METHOD FOR MANAGING GAS AND THERMAL FLOWS AT THE OUTLET OF A FUEL CELL TO POWER A HYDROGEN THERMAL ENGINE OR ITS AFTER-TREATMENT DEVICE

Abstract

Title: SYSTEM AND METHOD FOR MANAGING GAS AND HEAT FLOWS AT THE OUTLET OF A FUEL CELL TO POWER A HYDROGEN ENGINE OR ITS AFTER-TREATMENT DEVICE. This gas management system in a hydrogen hybrid vehicle (1), comprising an electric motor (2) and a hydrogen internal combustion engine (3), a fuel cell (4) supplying electrical energy to the electric motor (2), a hydrogen tank (5) supplying hydrogen to the fuel cell (4) and the internal combustion engine (3), an after-treatment device (6) adapted for treating the exhaust gases at the outlet of the internal combustion engine (3), the system comprising gas flow management means (16, 17, 18, 19) capable of selectively directing gas flows from the fuel cell (4) to the after-treatment device (6) and / or to the internal combustion engine (3), and / or from the hydrogen tank. (5) up to the fuel cell (4) and / or up to the internal combustion engine (3),and an electronic controller (15) configured to be able to control the gas flow management means (16, 17, 18, 19) according to the temperature of a first and / or a second gas flow emitted at the outlet of the fuel cell (4). Figure for the abstract: [Fig 1],

Description

Title of the invention: SYSTEM AND METHOD FOR MANAGING GAS AND THERMAL FLOWS AT THE FUEL CELL OUTPUT TO POWER AN ENGINE HYDROGEN THERMAL OR ITS POST-TREATMENT DEVICE Technical field

[0001] The present invention relates to the use of a fuel cell integrated into the powertrain of a hydrogen thermal vehicle.

[0002] The present invention aims to propose a system and a method which make it possible to manage the gaseous and thermal flows at the outlet of the fuel cell to supply the thermal engine, and / or its post-treatment device. Previous techniques

[0003] Vehicle traction systems are known which comprise a single hydrogen tank which can supply, on the one hand, a fuel cell which in turn supplies electrical energy to a first electric motor, and on the other hand, a second hydrogen thermal engine, so that the two engines can move the vehicle forward.

[0004] The vehicle operates either on the hydrogen thermal engine, particularly in cases of long journey times and high power requirements, or on the electric motor via the fuel cell, particularly in cases of short journeys or when low power requirements are required, or by using both engines at the same time.

[0005] Since the internal combustion of hydrogen generates gases and polluting particles at the outlet of the thermal engine, which must be treated before being emitted into the atmosphere, vehicles are equipped with a device for post-treatment of these pollutants to comply with the regulations in force, such as the European regulations known as "Euroôd full" or "EuroVI".

[0006] This post-treatment device generally contains one or more catalysts as well as one or more particulate filters.

[0007] The catalyzed elements have a variable operating temperature window.

[0008] For example, the cold trapping catalyst "PNA" (for the Anglicism "Passive NOx Adsorber") can store nitrogen oxides from the lowest temperatures, that is to say between one hundred and two hundred degrees Celsius, and releases nitrogen oxides above this temperature.

[0009] The association of a second nitrogen oxide treatment system in series, such as the "LNT" (for the anglicism "Lean NOx Trap") or the SCR (for the anglicism "Selective Catalyzed Reductor"), makes it possible to treat the emissions of nitrogen oxides released when the temperature of the gases reaches two hundred degrees Celsius and above: the nitrogen oxides are reduced to non-polluting gases emitted from the exhaust, in particular nitrogen.

[0010] In the context of a "PEMFC" (for the Anglicism "Proton Exchange Membrane Fuel Cell") cell operating above one hundred and sixty degrees Celsius, hot gases are emitted at the cell outlet, which still contain hydrogen from the cell anode and oxygen-depleted air from the cell cathode.

[0011] These gaseous streams are generally released directly into the atmosphere, which is harmful to the environment and suboptimal.

[0012] A particular problem of the invention therefore concerns the optimization of the thermal flows generated by the two systems and the use of hydrogen and compressed air, by using the gases leaving the fuel cell to directly supply the hydrogen thermal engine and / or activate its pollution control systems.

[0013] No means of controlling and managing the various thermal and energy flows exist in the state of the art for the use of hot hydrogen or oxygen emitted by a fuel cell for the post-treatment of gaseous emissions. Presentation of the invention

[0014] The invention aims to overcome at least some of the aforementioned drawbacks and to propose a system capable of combining performance advantages in terms of services, energy efficiency, simplicity and reliability for its implementation.

[0015] In view of the above, the subject of the invention is a gas management system in a hydrogen hybrid vehicle, comprising an electric motor and a hydrogen internal combustion engine, a fuel cell supplying electrical energy to the electric motor, a hydrogen tank supplying hydrogen to the cell and the heat engine, a post-treatment device adapted for treating the exhaust gases leaving the heat engine, characterized in that it comprises gas flow management means capable of selectively bringing gas flows 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,and an electronic controller configured to be able to control the gas flow management means as a function of the temperature of a first and / or a second gas flow emitted at the outlet of the fuel cell.

[0016] In one embodiment, the first gas stream emitted at the outlet of the fuel cell contains hydrogen and the system further comprises a temperature sensor temperature of this first flow, and the gas flow management means comprise a first valve adapted to bring a flow of hydrogen from the hydrogen tank to the fuel cell and / or to the internal combustion engine, and a second valve adapted to bring the first flow containing hydrogen from the fuel cell to the heat engine and / or to the post-treatment device, the electronic controller is configured to control the opening and closing of the first and / or second valves as a function of the temperature of the first gas flow.

[0017] For example, the post-treatment device further comprising a catalyst capable of treating nitrogen oxides from the internal combustion engine, the system further comprises a sensor of a concentration of nitrogen oxides in the catalyst, and the electronic controller is configured to control the opening and closing of the first and / or second valves as a function of the concentration of nitrogen oxides in the catalyst.

[0018] The invention also relates to a method for implementing the system defined above, comprising the following steps: - a first step during which the temperature of the first gas flow emitted at the outlet of the fuel cell is compared to a first threshold value, - if the first threshold value is exceeded during the first step, a second step during which a nitrogen oxide concentration measured in the catalyst is compared to a second threshold value, - if said second threshold value is exceeded during the second stage, a third stage during which the computer controls the second valve to bring the flow containing hydrogen from the fuel cell to the catalyst, - a fourth stage following the third stage, in which the hydrogen introduced into the catalyst during the third stage is used as a reactant in a reduction reaction with the nitrogen oxide present in the catalyst until the nitrogen oxide concentration in the catalyst is lowered below the second threshold value, - if the first threshold value is not exceeded during the first stage, a fifth stage during which the computer controls the second valve to bring the first gas flow containing hydrogen from the fuel cell to the heat engine.

[0019] Preferably, the second gas flow emitted at the outlet of the fuel cell contains oxygen, and the system further comprises a sensor for the temperature of this second gas flow, and the gas flow management means comprise a third valve adapted to bring the second gas flow containing oxygen from the fuel cell to the particulate filter, and a fourth valve adapted to bring the second gas flow containing oxygen from the fuel cell to the internal combustion engine, the electronic controller being able to control the opening and closing of the third and / or fourth valves as a function of the temperature of the second gas flow

[0020] In one embodiment of the system, the post-treatment device comprising a particulate filter capable of trapping nitrogen oxides from the heat engine, the system further comprises an oxygen richness sensor of the second gas flow, the electronic controller is configured to control the opening and closing of the third and / or fourth valves as a function of the oxygen concentration of the second gas flow

[0021] The invention also relates to a method for implementing the system comprising the following steps: - the first step during which the temperature of the second gas flow emitted at the outlet of the fuel cell is also compared to a third threshold value, - if the third threshold value is exceeded during the first stage, a sixth stage during which the oxygen concentration of the second gas flow leaving the fuel cell is compared to a fourth threshold value, - if the said fourth threshold value is not exceeded during the sixth step, a seventh step during which the computer controls the third valve to bring the second gas flow containing oxygen from the fuel cell to the particulate filter, - an eighth stage directly following the seventh stage, in which the oxygen supplied to the particulate filter in the seventh stage is used as a reactant in an oxidation reaction with the nitrogen oxide present in the particulate filter until the nitrogen oxide concentration in the particulate filter is reduced below the fourth threshold value, - if said fourth threshold value is exceeded by said oxygen concentration during the sixth step, a ninth step during which the computer controls the fourth valve to bring the second gas flow containing oxygen from the fuel cell to the heat engine.

[0022] Preferably, during the first step, both the temperature of the first gas stream containing hydrogen emitted at the outlet of the fuel cell is compared to the first threshold value and the temperature of the second gas stream containing oxygen emitted at the outlet of the fuel cell is compared to the third threshold value, the first stage continuing on the one hand with the second stage in the event of exceeding the first threshold value and on the other hand with the sixth stage in the event of exceeding the third threshold value.

[0023] The invention also relates to a vehicle comprising the preceding system for implementing the method as defined above. Brief description of the drawings

[0024] The invention will be better understood from a detailed study of an embodiment taken as a non-limiting example and illustrated by the appended drawings, in which:

[0025] [Fig-1] schematically represents the architecture of a gas management system according to the invention.

[0026] [Fig.2] represents the steps of the process implemented by the system. Detailed description

[0027] [Fig.l] illustrates the system according to the invention, which relates to a system 1 for managing gas in a hydrogen hybrid vehicle.

[0028] The system 1 comprises an electric motor 2 and a hydrogen internal combustion engine 3, a fuel cell 4 which supplies the motor 2 with electrical energy, a hydrogen tank 5 which supplies hydrogen to the cell 4 and the heat engine 3, and a post-treatment device 6 adapted for the treatment of the exhaust gases at the outlet of the heat engine 3.

[0029] The system 1 comprises gas flow management means 16, 17, 18, 19.

[0030] The management means 16, 17, 18, 19 are capable of selectively bringing flows gaseous from the fuel cell 4 to the post-treatment device 6 and / or to the heat engine 3, and / or from the hydrogen tank 5 to the fuel cell 4 and / or to the heat engine 3.

[0031] The system further comprises an electronic controller 15 configured to be able to control the management means 16, 17, 18, 19 as a function of the temperature of a first and / or a second gas flow emitted at the outlet of the fuel cell 4.

[0032] The hot gas is emitted from the fuel cell at a temperature greater than or equal to substantially one hundred and sixty degrees Celsius.

[0033] The first gas flow emitted at the outlet of the fuel cell 4 contains, for example, hydrogen.

[0034] In this case, the system 1 may further comprise a sensor for the temperature of this first gas flow.

[0035] The system 1 may also include a catalyst 7 capable of treating nitrogen oxides from the heat engine 3.

[0036] The catalyst 7 is coupled to the post-treatment device 6, and it is for example of the “PNA” or “LNT” type.

[0037] The gas flow management means 16, 17, 18, 19 then further comprise a first valve 16 adapted to be able to bring the hydrogen flow from the hydrogen tank 5 to the fuel cell 4 and / or to the heat engine 3, and a second valve 17 adapted to be able to bring the first gas flow, containing hydrogen, from the fuel cell 4 to the heat engine 3 and / or to the post-treatment device 6, the electronic controller 15 being configured to control the opening and closing of the first and / or second valves 16, 17 as a function of the temperature of the first gas flow.

[0038] The gas flow management means 16, 17, 18, 19 may further comprise an air filter 9 and an air compressor 10, coupled to an air inlet 11 and to a cooler 13 and to a humidifier 15 of this air, as well as a pump 15 and a silencer 20 coupled to said pump 15, coupled to the fluid distribution network in the vehicle, and optionally controlled by the controller 15.

[0039] The post-treatment device (6) further comprising a catalyst (7) capable of treating nitrogen oxides from the heat engine 3, the system 1 may further comprise a sensor for a concentration of nitrogen oxides in the catalyst 7.

[0040] The electronic controller 15 is then configured to control the opening and closing of the first and / or second valves as a function of the concentration of nitrogen oxides in the catalyst 7.

[0041] Thanks to this system 1, the driving of the vehicle comprising the system 1 is done partly or entirely thanks to the operation of the fuel cell 4, the hydrogen being consumed at the anode of said cell 4, and the excess hydrogen found at the outlet of said cell 4 can be reused.

[0042] [Fig.2] illustrates the method of implementing the system as described above, in which the hot gas comprises hydrogen.

[0043] The method comprises the following steps: - a first step El during which the temperature of the first gas flow emitted at the outlet of the fuel cell 4 is compared to a first threshold value, - if the first threshold value is exceeded during the first step E1, a second step E2 during which a nitrogen oxide concentration measured in the catalyst 7 is compared to a second threshold value, - if said second threshold value is exceeded during the second step E2, a third step E3 during which the computer 15 controls the second valve 17 to bring the flow containing hydrogen from the fuel cell 4 to the catalyst 7, - a fourth step E4 following the third step E3, during which the hydrogen brought into catalyst 7 during the third step E3 is used as a reactant in a reduction reaction with the nitrogen oxide present in catalyst 7 until the nitrogen oxide concentration in catalyst 7 is lowered below the second threshold value, - if the first threshold value is not exceeded during the first step E1, a fifth step E2 during which the computer 15 controls the second valve 17 to bring the first gas flow containing hydrogen from the fuel cell 4 to the heat engine 3.

[0044] This method allows the detection and optimal use of excess hydrogen at the outlet of the fuel cell 4, which is not possible with any system of the prior art.

[0045] Indeed, on the one hand, if the storage of nitrogen oxides in the catalyst 7 trapping the nitrogen oxides requires entering the reduction phase, the hydrogen emitted by the anode of the cell can then be used hot for the reduction of these nitrogen oxides.

[0046] On the other hand, if the reduction of nitrogen oxides in the catalyst 7 trapping the nitrogen oxides is not necessary, then the hydrogen emitted by the anode can be injected into the combustion chamber of the hydrogen heat engine 2 as fuel, and a new combustion cycle can then take place.

[0047] According to one embodiment, the second gas flow emitted at the outlet of the fuel cell 4 contains oxygen in addition to or as an alternative to the emitted hydrogen, and the system 1 and the method differ.

[0048] Indeed, when the vehicle comprising the system 1 is driven partly or entirely by the operation of the fuel cell 4, an excess of oxygen may be found at the outlet of said cell 4.

[0049] System 1 also makes it possible to optimize the management of this oxygen.

[0050] In this case where the second gas flow emitted at the outlet of the fuel cell 4 contains oxygen, system 1 also includes a sensor for the temperature of this second gas flow.

[0051] In addition, the gas flow management means 16, 17, 18, 19 comprise a third valve 18 adapted to bring the second gas flow containing oxygen from the fuel cell 4 to the particle filter 8, and a fourth valve 19 adapted to be able to direct a flow of oxygen from the fuel cell 4 to the heat engine 3, the electronic controller 15 being able to control the opening and closing of the third and / or fourth valves 18, 19 as a function of the temperature of the second gas flow.

[0052] The post-treatment device 6 comprising a particle filter 8 capable of trapping nitrogen oxides from the heat engine 3, it is also possible to provide for the addition of an oxygen richness sensor for the second gas flow, the electronic controller 15 being configured to control the opening and closing of the third and / or fourth valves 18, 19 as a function of the oxygen concentration of said second gas flow.

[0053] Thus, a system is obtained which allows that if the storage of the particles in the particle filter 6 of the exhaust line of the thermal engine 2 requires entering the oxidation phase, the oxygen emitted by the cathode of the cell 4 can then be used hot for the oxidation of these particles.

[0054] On the other hand, if the storage of particles in the particle filter 6 of the exhaust line of the heat engine 2 is not necessary, and a lean mixture is envisaged in the combustion chamber, that is to say that the air leaving the cell 4 is depleted in oxygen because part of it has been consumed, then the oxygen emitted by the cathode can be injected as an oxidant, and a new combustion cycle can then take place.

[0055] In this case, the gas where the heat emitted at the outlet of the fuel cell 4 comprises oxygen, the method comprises the following steps: - the first step El during which the temperature of the second gas flow emitted at the outlet of the fuel cell 4 is also compared to a third threshold value, - if the third threshold value is exceeded during the first step E1, a sixth step E6 during which the oxygen concentration of the second gas flow leaving the fuel cell 4 is compared to a fourth threshold value, - in the absence of exceeding said fourth threshold value during the sixth step E6, a seventh step E7 during which the computer 15 controls the third valve 18 to bring the second gas flow containing oxygen from the fuel cell 4 to the particle filter 8, - an eighth step E8 directly following the seventh step E7, during which the oxygen brought into the particulate filter 8 during the seventh step E7 is used as a reactant for an oxidation reaction with the nitrogen oxide present in the particulate filter 8 until the nitrogen oxide concentration in said particulate filter 8 is lowered below the fourth threshold value, - in the event that said fourth threshold value is exceeded by said oxygen concentration during the sixth step E6, a ninth step E9 during which the computer 15 controls the fourth valve 19 to bring the second gas flow containing oxygen from the fuel cell 4 to the heat engine 3.

[0056] This method is compatible with the method described previously for the case where the hot gas emitted at the outlet of the fuel cell 4 comprises hydrogen.

[0057] Indeed, the system 1 can further provide that the hot gas emitted at the outlet of the fuel cell 4 comprises both hydrogen and oxygen.

[0058] The gas flow management means 16, 17, 18, 19 may then comprise first, second, third and fourth valves 16, 17, 18, 19, and provide that the electronic controller 15 is configured to be able to control said valves.

[0059] Preferably, such a system is implemented by a method combining the methods described previously evaluating the temperature of a hot gas emitted at the outlet of the fuel cell 4, and during the first step E1, both the temperature of the first gas stream containing hydrogen emitted at the outlet of the fuel cell 4 are compared to the first threshold value and the temperature of the second gas stream containing oxygen emitted at the outlet of the fuel cell 4 to the first threshold value and the temperature of the oxygen in the hot gas emitted at the outlet of the fuel cell 4 to the third threshold value.

[0060] The first step E1 continues on the one hand with the second step E2 in the event of the first threshold value being exceeded and on the other hand with the sixth step E6 in the event of the third threshold value being exceeded.

[0061] The invention also relates to a vehicle comprising the preceding system for implementing the method described, in particular a motor vehicle.

[0062] A solution is thus obtained allowing the implementation of a strategy for managing the output flows from the fuel cell 4 to the hydrogen thermal engine 2 and / or its post-treatment system 6, which makes it possible to substantially limit the consumption of hydrogen as fuel, as well as compressed oxygen used as oxidant, by optimizing their use and allowing better management of the thermal performance of the two systems.

Claims

Claims

1. Gas management system in a hydrogen hybrid vehicle (1), comprising an electric motor (2) and a hydrogen internal combustion engine (3), a fuel cell (4) supplying electrical energy to the electric motor (2), a hydrogen tank (5) supplying hydrogen to the cell (4) and the heat engine (3), a post-treatment device (6) adapted for treating the exhaust gases leaving the heat engine (3), characterized in that it comprises gas flow management means (16, 17, 18, 19) capable of selectively bringing gas flows from the fuel cell (4) to the post-treatment device (6) and / or to the heat engine (3), and / or from the hydrogen tank (5) to the fuel cell (4) and / or to the heat engine (3), and an electronic controller (15) configured to be able to control the gas flow management means (16, 17, 18,19) depending on the temperature of a first and / or a second gas flow emitted at the outlet of the fuel cell (4).,

2. System (1) according to claim 1, in which, the first gas flow emitted at the outlet of the fuel cell (4) containing hydrogen, the system (1) further comprises a sensor for the temperature of this first flow, the gas flow management means (16, 17, 18, 19) comprise a first valve (16) adapted to bring a flow of hydrogen from the hydrogen tank (5) to the fuel cell (4) and / or to the heat engine (3), and a second valve (17) adapted to bring the first flow containing hydrogen from the fuel cell (4) to the heat 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) as a function of the temperature of the first gas flow.

3. System (1) according to claim 2, the post-treatment device (6) further comprising a catalyst (7) capable of treating nitrogen oxides from the heat engine (3), the system further comprises a sensor for a concentration of nitrogen oxides in the catalyst (7), and the electronic controller (15) is configured to control the opening and closing of the first and / or second valves (16, 17) as a function of the concentration of nitrogen oxides in the catalyst (7).

4. Method for implementing a system (1) according to claim 3, comprising the following steps: - a first step (El) during which the temperature of the first gas flow emitted at the outlet of the fuel cell (4) is compared to a first threshold value, - if the first threshold value is exceeded during the first step (El), a second step (E2) during which a nitrogen oxide concentration measured in the catalyst (7) is compared with a second threshold value, - if said second threshold value is exceeded during the second step (E2), a third step (E3) during which the computer (15) controls the second valve (17) to bring the flow containing hydrogen from the fuel cell (4) to the catalyst (7), - a fourth step (E4) following the third step (E3), during which the hydrogen brought into the catalyst (7) during the third step (E3) is used as a reactant for a reduction reaction with the nitrogen oxide present in the catalyst (7) until the nitrogen oxide concentration in the catalyst (7) is lowered below the second threshold value, - if the first threshold value is not exceeded during the first step (El), a fifth step (E2) during which the computer (15) controls the second valve (17) to bring the first gaseous flow containing hydrogen from the fuel cell (4) to the heat engine (3).

5. System (1) according to any one of claims 1 to 3, in which the second gas flow emitted at the outlet of the fuel cell (4) contains oxygen, the system (1) further comprises a particle filter (8) and a sensor for the temperature of this second gas flow, the gas flow management means (16, 17, 18, 19) comprising a third valve (18) adapted to bring the second gas flow containing oxygen from the fuel cell (4) to the particle filter (8), and a fourth valve (19) adapted to bring the second gas flow containing oxygen from the fuel cell (4) to the heat engine (3), the electronic controller (15) being capable of controlling the opening and closing of the third and / or fourth valves (18, 19) as a function of the temperature of said second gas flow.

6. System (1) according to claim 5, the post-treatment device (6) comprising a particulate filter (8) capable of trapping nitrogen oxides from the heat engine (3), the system further comprising an oxygen richness sensor of the second gas flow, the electronic controller (15) is configured to control the opening and closing of the third and / or fourth valves (18, 19) as a function of the oxygen concentration of said second gas flow.

7. Method for implementing a system (1) according to any one of claims 5 and 6, comprising the following steps: - the first step (El) during which the temperature of the second gas flow emitted at the outlet of the fuel cell (4) is further compared to a third threshold value, - if the third threshold value is exceeded during the first step (El), a sixth step (E6) during which the oxygen concentration of the second gas flow at the outlet of the fuel cell (4) is compared to a fourth threshold value, - if said fourth threshold value is not exceeded during the sixth step (E6), a seventh step (E7) during which the computer (15) controls the third valve (18) to bring the second gas flow containing oxygen from the fuel cell (4) to the particulate filter (8), - an eighth step (E8) directly following the seventh step (E7),in which the oxygen supplied to the particle filter (8) in the seventh step (E7) is used as a reactant in an oxidation reaction with the nitrogen oxide present in the particle filter (8) until the nitrogen oxide concentration in the particle filter (8) is lowered below the fourth threshold value, - in the event that said fourth threshold value is exceeded by said oxygen concentration in the sixth step (E6), a ninth step (E9) in which the computer (15) controls the fourth valve (19) to supply the second gas flow containing oxygen from the fuel cell, fuel (4) to the heat engine (3).

8. Method according to claim 7, in which during the first step (El), both the temperature of the first gaseous flow containing hydrogen emitted at the outlet of the fuel cell (4) is compared to the first threshold value and the temperature of the second gaseous flow containing oxygen emitted at the outlet of the fuel cell (4) is compared to the third threshold value, the first step (El) continuing on the one hand with the second step (E2) in the event of the first threshold value being exceeded and on the other hand with the sixth step (E6) in the event of the third threshold value being exceeded.

9. Vehicle comprising a system (1) according to any one of claims 1 to 3, 5 and 6, for implementing a method according to any one of claims 4, 7 and 8.

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