METHOD FOR VERIFYING THE RESULTS OF A LEAK DETECTION METHOD IN A DIHYDROGEN STORAGE AND SUPPLY CIRCUIT

Abstract

One aspect of the invention relates to a method (100) for verifying the results of a leak detection method in a hydrogen storage and supply circuit of a vehicle fuel cell, said method 100 comprising the steps of: Determining (101), during each step of said method, a change in at least one parameter reflecting a hydrogen leak; Verifying (102), using a state machine, each transition from step n to step n+1 executed by said method; If said change in said at least one parameter is, according to the at least one parameter, below or above a threshold, identifying (103) a leak; If an order of transitions is incorrect or if only part of the transitions are executed, identifying (104) a defect in said method. Figure 3

Description

Title of the invention: METHOD FOR VERIFYING THE RESULTS OF A DETECTION METHOD LEAKS IN A DIHYDROGEN STORAGE AND SUPPLY CIRCUIT

[0001] The present invention relates to a method for verifying the results of a leak detection method in a hydrogen storage and supply circuit of a fuel cell in a motor vehicle. The invention thus relates to the technical field of motor vehicles equipped with a fuel cell.

[0002] Motor vehicles equipped with a fuel cell enabling the production of electrical energy by an electrochemical reaction, as well as a circuit for storing and supplying dihydrogen to this fuel cell, are known.

[0003] In order to ensure the safe operation of the hydrogen storage and supply circuit, and to maintain optimal performance of this fuel cell, it is important to detect any leaks in the hydrogen storage and supply circuit.

[0004] A fuel cell 200 associated with a hydrogen storage and supply circuit 201 for this fuel cell 200 are shown in [Fig. 1]. This fuel cell 200 and this hydrogen storage and supply circuit 201 are intended to be integrated into a vehicle in order to produce electrical energy to power an electric motor and / or to recharge the traction battery of said vehicle.

[0005] The hydrogen storage and supply circuit 201 comprises one or more tank(s) 202 containing pressurized hydrogen, for example at 350 bar or 700 bar. Each tank 202 has at its outlet a first solenoid valve 203 forming a first stage of pressure reduction of approximately 50 bar.

[0006] The hydrogen storage and supply circuit 201 also includes a first high-pressure circuit 204 arranged between the first solenoid valve(s) 203 and a second solenoid valve 205. This second solenoid valve 205 forms a second stage of pressure reduction of approximately 50 bars.

[0007] The hydrogen storage and supply circuit 201 further comprises a second high-pressure circuit 206 disposed between the second solenoid valve 205 and a pressure regulator 207 for regulating the hydrogen pressure at a usable pressure at the inlet of the fuel cell 200 and a medium pressure circuit 208 arranged between the pressure regulator 207 and the fuel cell 200.

[0008] Given the complete non-sealing of the first and second solenoid valves 203, 205 which comprise the dihydrogen storage and supply circuit 201 and the natural ability of dihydrogen to diffuse through all materials, it is required to implement a method for detecting possible dihydrogen leaks when the first and second solenoid valves 203, 205 are closed and the fuel cell 200 is shut down.

[0009] For example, a method for detecting dihydrogen leakage in a fuel cell system, known from document FR-B1-3123985, is known from document FR-B1-3123985. This method consists of determining a leakage rate by calculating the difference between the dihydrogen flow rate admitted and the total dihydrogen flow rate consumed by the fuel cell.

[0010] A method for detecting leaks in a hydrogen storage and supply circuit of a fuel cell comprising four stages is also known.

[0011] More specifically, when the vehicle is stopped, the method includes a first step of closing each first solenoid valve 203 during the operation of the fuel cell 200, which consumes dihydrogen, and measuring the pressure in the first high-pressure circuit 204. This first step allows the dihydrogen pressure in the first high-pressure circuit 204 to drop and for a pressure sensor to verify that the pressure reached in the first high-pressure circuit 204 corresponds to an expected pressure. If the pressure reached is lower than the expected pressure, a leak is then detected.

[0012] The method then includes a second step of closing the second solenoid valve 205 while the fuel cell 200 continues to operate and measuring the pressure in the second high-pressure circuit 206. This second step allows the hydrogen pressure in the second high-pressure circuit 206 to drop and for a pressure sensor to verify that the pressure reached in the second high-pressure circuit 206 corresponds to an expected pressure. If the pressure reached is lower than the expected pressure, a leak is detected.

[0013] Then, the method includes a third step of closing the first and second solenoid valves 203, 205 while simultaneously stopping the operation of the fuel cell 200 so that it no longer consumes dihydrogen and measuring the pressure in the first high-pressure circuit 204. Thus, if the pressure of the first high-pressure circuit 204 continues to decrease despite the closing of the first and second solenoid valves 203, 205, then a leak is detected.

[0014] Finally, the method includes a fourth step of measuring the pressure in the second high-pressure circuit 206 while the first and second solenoid valves 203, 205 are closed and the operation of the fuel cell 200 is stopped. Thus, if the pressure in the second high-pressure circuit 206 continues to decrease despite the closure of the first and second solenoid valves 203, 205, then a leak is detected.

[0015] However, it is possible that such a method of detecting leaks in a hydrogen storage and supply circuit of a fuel cell may malfunction, resulting in the non-detection of a leak in the hydrogen storage and supply circuit of a fuel cell.

[0016] The invention offers a solution to the problem mentioned above, by proposing a method for verifying the results of a leak detection method in a hydrogen storage and supply circuit of a fuel cell, thereby improving the ability to detect hydrogen leaks.

[0017] In this context, the invention thus relates, in its broadest sense, to a method for verifying the results of a leak detection method in a hydrogen storage and supply circuit of a vehicle fuel cell, said method being remarkable in that, when said method is carried out, it comprises the steps, performed by vehicle control means, of: • Determine, during each step of the detection of a dihydrogen leak of said method, an evolution of at least one parameter reflecting a dihydrogen leak in the dihydrogen storage and supply circuit; • Verify, with a state machine executed by said method, each transition passage from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by said method; • If the said evolution of the said at least parameter reflecting a determined leak is, according to the at least one parameter, lower or higher than a threshold, identify a dihydrogen leak; • If the order in which transitions are executed is incorrect, or if only part of the transitions are executed, identify the execution failure of said method.

[0018] Thanks to the method according to this aspect of the invention, in parallel with the execution of the leak detection method in a hydrogen storage and supply circuit, a second check is made to see if a leak is present in the hydrogen storage and supply circuit. In addition, the steps of The method for detecting a hydrogen leak is performed in the correct order, ensuring that all steps are executed. If the order is not followed or if all steps are not performed, a fault in the execution of the leak detection method in a hydrogen storage and supply circuit is also identified. This method thus increases the robustness of the method for detecting potential leaks in the hydrogen storage and supply circuit of a fuel cell in a vehicle.

[0019] In addition to the characteristics just mentioned in the preceding paragraph, the process according to this aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations.

[0020] According to a non-limiting aspect of the invention, for a dihydrogen storage and supply circuit comprising: • One or more tank(s), each tank being equipped with a first solenoid valve; • A first high-pressure circuit connected to the first solenoid valve(s) and to a second solenoid valve; • A second high-pressure circuit connected to the second solenoid valve and a pressure regulator; and • A medium pressure circuit connected to the pressure regulator and the fuel cell; • The step of determining a change in at least one parameter reflecting a dihydrogen leak in the dihydrogen storage and supply circuit includes the following steps: • When, during a first step of the method for detecting a dihydrogen leak, each first solenoid valve is closed and the fuel cell is in operation, determine a change in at least one first parameter reflecting a dihydrogen leak in the first high-pressure circuit or the second high-pressure circuit; • When, during a second step of detecting a dihydrogen leak of said method, the first and second solenoid valves are closed and the fuel cell is in operation, determine a change in at least one second parameter reflecting a dihydrogen leak in the second high-pressure circuit; • When, during a third step of the hydrogen leak detection procedure of said method, the first and second solenoid valves are closed and the operation of the fuel cell is stopped, determine an evolution of at least a third parameter reflecting a leak of dihydrogen in the first high-pressure circuit; • When, during a fourth step of detecting a dihydrogen leak of said method, the first and second solenoid valves are closed and the operation of the fuel cell is stopped, determine a change in at least a fourth parameter reflecting a dihydrogen leak in the second high-pressure circuit; • A dihydrogen leak is identified if the evolution of at least one first, second, third or fourth parameter reflecting a determined leak is, according to at least one first, second, third or fourth parameter, lower or higher than a threshold associated with the first, second, third or fourth parameter.

[0021] According to a non-limiting aspect of the invention, the step of verifying, with a state machine executed by the method, each transition from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by said method comprises the steps of: • Verify, with said state machine, a first transition from the first step of detecting a dihydrogen leak to the second step of detecting a dihydrogen leak executed by said method; • Verify, with said state machine, a second transition from said second step of detecting a dihydrogen leak to the third step of detecting a dihydrogen leak executed by said method; • Verify, with said state machine, a third transition from said third step of detecting a dihydrogen leak to the fourth step of detecting a dihydrogen leak executed by said method; • Verify, with said state machine, a fourth transition from said fourth step of detecting a dihydrogen leak to a final dihydrogen leak detection step executed by said method; • A failure to execute said method is identified if the order of passage of the first, second, third and fourth transitions is incorrect or if only part of the first, second, third and fourth transitions are executed.

[0022] According to a non-limiting aspect of the invention, when at least one first parameter is formed by: • A pressure of dihydrogen in the first high-pressure circuit, • Hydrogen pressure in the second high-pressure circuit, and / or • Consumption of an initial quantity of dihydrogen contained in the dihydrogen storage and supply circuit, • A leak is identified if: • The evolution of said dihydrogen pressure in the first high-pressure circuit is below a first pressure threshold; • The evolution of said dihydrogen pressure in the second high-pressure circuit is below a second pressure threshold; and / or • The evolution of said consumption of a first quantity of dihydrogen is less than a first consumption threshold.

[0023] According to a non-limiting aspect of the invention, when at least a second parameter is formed by: • Hydrogen pressure in the second high-pressure circuit, and / or • Consumption of a second quantity of dihydrogen contained in the dihydrogen storage and supply circuit, • A leak is identified if: • The evolution of said dihydrogen pressure in the second high-pressure circuit is below a third pressure threshold; and / or • The evolution of said consumption of a second quantity of dihydrogen is below a second consumption threshold. According to a non-limiting aspect of the invention, when at least a third parameter is formed by: • Time spent performing the third step of the method, which involves detecting a dihydrogen leak. • A dihydrogen pressure in the first high-pressure circuit, and / or • A temperature of dihydrogen in the first high-pressure circuit, • A leak is identified if: • The evolution of the time spent for the execution of the third step of detecting a dihydrogen leak of the method is greater than a first time threshold; • The evolution of said dihydrogen pressure in the first high-pressure circuit is below a fourth pressure threshold, and / or • The evolution of the temperature of dihydrogen in the first high-pressure circuit is below a first temperature threshold.

[0024] According to a non-limiting aspect of the invention, when at least a fourth parameter is formed by: • Time spent performing the fourth step of the dihydrogen leak detection method, • Hydrogen pressure in the second high-pressure circuit, and / or • The temperature of the dihydrogen in the second high-pressure circuit, • A leak is identified if: • The time spent performing the fourth step of the method, which detects a dihydrogen leak, exceeds a second time threshold; and / or • The evolution of said dihydrogen pressure in the second high-pressure circuit is less than a fifth pressure threshold, and / or • The evolution of the temperature of dihydrogen in the second high-pressure circuit is below a second temperature threshold.

[0025] According to a non-limiting aspect of the invention, when a leak is detected, the process performs a step to degrade or prohibit the operation of the fuel cell.

[0026] According to a non-limiting aspect of the invention, the method includes a step of inhibiting the step of degrading or prohibiting the operation of the fuel cell when: • The method and process detect a dihydrogen leak; • The method is interrupted by the activation of another method.

[0027] Another aspect of the invention relates to a motor vehicle comprising a hydrogen storage and supply circuit for a fuel cell comprising: • One or more tank(s), each tank being equipped with a first solenoid valve; • A first high-pressure circuit connected to the first solenoid valve(s) and to a second solenoid valve; • A second high-pressure circuit connected to the second solenoid valve and a pressure regulator; and • A medium pressure circuit connected to the pressure regulator and the fuel cell; • Said vehicle being remarkable in that it includes control means arranged to execute the steps of the process according to any one of the aforementioned aspects of the invention.

[0028] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0029] [Fig.1] illustrates a method for detecting leaks in a hydrogen storage and supply circuit of a fuel cell included in a motor vehicle according to the prior art.

[0030] [Fig.2] illustrates a motor vehicle equipped with a hydrogen storage and supply circuit for a fuel cell according to the invention.

[0031] [Fig.3] shows the steps of a method for verifying the results of a leak detection method in a hydrogen storage and supply circuit of a fuel cell included in a motor vehicle according to the invention.

[0032] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0033] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0034] More particularly, [Fig.2] schematically illustrates a motor vehicle 1 equipped with a hydrogen storage and supply circuit 2 of a fuel cell 3 according to the invention.

[0035] The hydrogen storage and supply circuit 2 comprises two tanks 4 containing pressurized hydrogen, for example at 350 bar. Each tank 4 has at its outlet a first solenoid valve 5 forming a first stage of pressure reduction, for example by 50 bar. According to other embodiments not illustrated, the hydrogen storage and supply circuit 2 comprises n tank(s).

[0036] The hydrogen storage and supply circuit 2 also includes a first high-pressure circuit 6 connected to the first solenoid valves 5 and a second solenoid valve 7. In the example described, the pressure in the first high-pressure circuit 6 is 300 bar. The hydrogen storage and supply circuit 2 also includes a first pressure sensor PI and a first temperature sensor TL. The first pressure sensor PI is arranged to measure the pressure in the first high-pressure circuit 6, and the first temperature sensor TL is arranged to measure the temperature in the first high-pressure circuit 6.

[0037] The hydrogen storage and supply circuit 2 further comprises a second high-pressure circuit 8 connected to the second solenoid valve 7 and a pressure regulator 9. The second solenoid valve 7 forms a second pressure reduction stage, for example from 50 bar. In the example described, the pressure in the second high-pressure circuit 8 is 250 bar.

[0038] The hydrogen storage and supply circuit 2 also includes a second pressure sensor P2 and a second temperature sensor T2. The second pressure sensor P2 is arranged to measure the pressure in the second high-pressure circuit 8 and the second temperature sensor T2 is arranged to measure the temperature in the second high-pressure circuit 8.

[0039] The hydrogen storage and supply circuit 2 also includes a medium pressure circuit 10 connected to the pressure regulator 9 and to the fuel cell 3. The pressure regulator 9 allows the pressure circulating in the medium pressure circuit 10 to be lowered to a pressure acceptable to the fuel cell 3.

[0040] The vehicle 1 further comprises control means 11 arranged to carry out the process 100 according to the invention as illustrated in [Fig.3].

[0041] Figure 3 shows the steps of a method for verifying the results of a level 1 detection method for dihydrogen leaks in a circuit of storage and supply of dihydrogen 2 to a fuel cell 3 which comprises a motor vehicle 1 as illustrated in [Fig.2].

[0042] The method 100 comprises, when the vehicle 1 is stopped and the leak detection method is executed, a step of determining 101, during each step of detecting a dihydrogen leak of said method, an evolution of at least one parameter reflecting a dihydrogen leak in the dihydrogen storage and supply circuit 2.

[0043] According to a non-limiting example of embodiment, the step of determining 101, during each step of detecting a dihydrogen leak of the method, an evolution of at least one parameter reflecting a dihydrogen leak in the dihydrogen storage and supply circuit 2 comprises four steps 101 b 1012, 1013, 1014.

[0044] More particularly, when, during a first step of detecting a dihydrogen leak in the detection method, the first solenoid valves 5 are closed and the fuel cell 3 is in operation, the method 100 includes a step of determining 1011 the evolution of at least a first parameter reflecting a leak in the first high-pressure circuit 6 and / or a leak in the second high-pressure circuit 8.

[0045] According to a non-limiting example of embodiment, the at least one first parameter is formed by a pressure of dihydrogen in the first high pressure circuit 6 measured by means of the first pressure sensor PI, a pressure of dihydrogen in the second high pressure circuit 8 measured by means of the second pressure sensor P2 as well as a consumption of a first quantity of dihydrogen which contains the dihydrogen storage and supply circuit 2.

[0046] These pressures measured in the first and second high-pressure circuits Pressures 6 and 8 are transmitted by the first and second pressure sensors PI and P2 to the control means 11, which then determine the evolution of these pressures during the first step of the method. The consumption of an initial quantity of dihydrogen can be directly transmitted by a control means of the fuel cell 3 to the control means 11, which then determine the evolution of consumption during the first step of the method. Consumption can be determined by the control means of the fuel cell 3 based on a chemical reaction generated within the fuel cell 3: H2 + / 2 O2 = H2O.

[0047] Then, when, during a second step of the detection method for detecting a dihydrogen leak, the first and second solenoid valves 5, 7 are closed and the fuel cell 3 is operating, the method 100 includes a step 1012 for determining the evolution of at least one second parameter reflecting a leak in the second high-pressure circuit 8. According to a non-limiting embodiment, the at least one second parameter is formed by a pressure of the The pressure of dihydrogen in the second high-pressure circuit 8 is measured by means of the second pressure sensor P2, and a second quantity of dihydrogen is consumed. This pressure measured in the second high-pressure circuit 8 is transmitted by the second pressure sensor P2 to the control means 11, which then determine the evolution of this pressure during the second step of the method. The consumption of the second quantity of dihydrogen can be directly transmitted by a fuel cell control means 3 to the control means 11, which then determine the evolution of consumption during the second step of the method.

[0048] When, during a third step of detecting a dihydrogen leak in the detection method, the first and second solenoid valves 5, 7 are closed and the operation of the fuel cell 3 is stopped, the method 100 includes a step of determining 1013 the evolution of at least a third parameter reflecting a leak in the first high-pressure circuit 6.According to a non-limiting example of an embodiment, at least a third parameter is formed by a pressure of dihydrogen in the first high-pressure circuit 6 measured by the first pressure sensor PI and a temperature of dihydrogen in the first high-pressure circuit 6 measured by the first temperature sensor TL. This measured pressure of dihydrogen in the first high-pressure circuit 6 is transmitted by the first pressure sensor PI to the control means 11 and the measured temperature of the dihydrogen in the first high-pressure circuit 6 is transmitted by the first temperature sensor TL to the control means 11 which will then determine the evolution of this pressure and this temperature during the third step of the method.

[0049] According to a non-limiting embodiment, the at least third parameter is formed by the time spent by the detection method executing the third step of detecting a dihydrogen leak. The evolution of this time can be determined by the control means 11 from information obtained from a state machine executed by the method, referred to as level 1. Indeed, at each step of detecting a dihydrogen leak in the method, the method executes a state machine that records the transition from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1. The time for executing the third step can thus be determined by the control means 11 from this state machine.By retrieving information from this state machine, for example itself executed on the control means 11, the process 100 can calculate the time elapsed between the transition from step 2 to step 3 of detecting a dihydrogen leak and the . transition from step 3 to step 4 of the method for detecting a dihydrogen leak, and deduce the evolution of the time spent performing step 3.

[0050] When, during the fourth step of detecting a dihydrogen leak in the detection method, the first and second solenoid valves 5, 7 are closed and the operation of the fuel cell 3 is stopped, the method 100 includes a step of determining 1014 the evolution of at least one fourth parameter reflecting the pressure in the second high-pressure circuit 8. According to a non-limiting embodiment, the at least one fourth parameter is formed by a pressure of the dihydrogen in the second high-pressure circuit 8 measured by the second pressure sensor P2 and a temperature of the dihydrogen in the second high-pressure circuit 8 measured by the second temperature sensor T2.The measured pressure of the dihydrogen in the second high-pressure circuit 8 is transmitted by the second pressure sensor P2 to the control means 11, and the measured temperature of the dihydrogen in the second high-pressure circuit 8 is transmitted by the second temperature sensor T2 to the control means 11. The control means 11 will then determine the evolution of this pressure and temperature during the fourth step of the method.

[0051] According to a non-limiting embodiment, at least a fourth parameter is formed by the time spent by the detection method performing the fourth step of detecting a dihydrogen leak. The evolution of this spent time can be determined by the control means 11 from information obtained from the state machine executed by the method. By retrieving information from this state machine, the process 100 can calculate the elapsed time between the transition from step 3 to step 4 of detecting a dihydrogen leak and the transition from step 4 to a final dihydrogen leak detection step, and deduce the evolution of the time spent performing step 4.

[0052] The method 100 also includes a step of verifying 102, with the state machine executed by the method, each transition passage from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by said method.

[0053] According to a non-limiting example of an embodiment, the step of verifying 102 each transition passage from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by the method comprises four steps 102i, 1022, 1033, 1044.

[0054] According to this non-limiting embodiment, the process 100 comprises a step of verifying 102^ with the state machine executed by the detection method, a first transition from the first step of detecting a dihydrogen leak to the The second step of detecting a dihydrogen leak is carried out by the detection method. To this end, the control means 11 collect information from the state machine executed by the method, indicating that the first transition between step 1 and step 2 of the method has been carried out.

[0055] The process 100 also includes a step 1022 for verifying, with the state machine, a second transition from the second step of detecting a dihydrogen leak to the third step of detecting a dihydrogen leak executed by the detection method. To this end, the control means 11 collect information from the state machine indicating that the second transition between step 2 and step 3 of the method has been carried out.

[0056] The process 100 also includes a step 1023 for verifying with the state machine a third transition from the third step of detecting a dihydrogen leak to the fourth step of detecting a dihydrogen leak executed by the detection method. To this end, the control means 11 collect information from the state machine indicating that the third transition between step 3 and step 4 of the method has been carried out.

[0057] The process 100 also includes a step 1024 for verifying with the state machine a fourth transition from the fourth step of detecting a dihydrogen leak to the final dihydrogen leak detection step. To this end, the control means 11 collect information from the state machine indicating that the fourth transition between step 4 and the final dihydrogen leak detection step of the method has been carried out.

[0058] If the evolution of the at least parameter reflecting a determined dihydrogen leak is, according to the at least one parameter, lower or higher than a threshold, the process 100 includes a step of identifying 103 a dihydrogen leak.

[0059] Thus, in the example described, if the evolution of at least one first, second, third or fourth parameter reflecting a determined leak is, according to at least one first, second, third or fourth parameter, lower or higher than an associated threshold, the process 100 identifies a dihydrogen leak.

[0060] For example, for at least a first parameter which is formed by a dihydrogen pressure in the first high-pressure circuit 6, a dihydrogen pressure in the second high-pressure circuit 8 and a consumption of a first quantity of dihydrogen, if the evolution of the dihydrogen pressure in the first high-pressure circuit 6 is less than a first pressure threshold, for example between 45 bar and 55 bar, and / or that the evolution of the dihydrogen pressure in the second high-pressure circuit 8 is less than a second pressure threshold, for example between 45 bar and 55 bar and / or that the first quantity of dihydrogen consumed is less than a first consumption threshold, by example of 0.01g, then a leak of dihydrogen is identified by the control means 11.

[0061] In addition, without limitation, for at least a second parameter which is formed by a pressure of dihydrogen in the second high pressure circuit 8 and a consumption of a second quantity of dihydrogen, if the evolution of the pressure of dihydrogen in the second high pressure circuit 8 is less than a third pressure threshold, for example between 45 bars and 55 bars, and / or the second quantity of dihydrogen consumed is less than a second consumption threshold, for example of 0.002g, then a leak of dihydrogen is identified by the control means 11.

[0062] For at least a third parameter which is formed by a pressure of dihydrogen in the first high pressure circuit 6 and a temperature of dihydrogen in the first high pressure circuit 6, if the evolution of the pressure of dihydrogen in the first high pressure circuit 6 is less than a fourth pressure threshold between 0.5 bar and 1.5 bar and / or the evolution of the temperature of dihydrogen in the first high pressure circuit 6 is less than a first temperature threshold, for example between 0.5°C and 1.5°C, then a leak of dihydrogen is identified by the control means 11.

[0063] According to a different example, when at least a third parameter is formed by a time spent for the execution of the third step of detection of a dihydrogen leak of the detection method, if the time spent is greater than a first time threshold, then a dihydrogen leak is identified by the control means 11.

[0064] For at least a fourth parameter which is formed by a pressure of dihydrogen in the second high pressure circuit 8 and a temperature of dihydrogen in the second high pressure circuit 8, if the evolution of the pressure of dihydrogen in the second high pressure circuit 8 is less than a fifth pressure threshold, for example between 0.5 bar and 1.5 bar and / or the evolution of the temperature of dihydrogen in the second high pressure circuit 8 is less than a second temperature threshold, for example between 0.5°C and 1.5°C, then a leak of dihydrogen is identified by the control means 11.

[0065] According to a different example, when at least a fourth parameter is formed by a time spent for the execution of the fourth step of detecting a dihydrogen leak of the detection method, if the time spent is greater than a second time threshold, then a dihydrogen leak is identified by the control means 11.

[0066] Furthermore, if the order in which the transitions are executed is incorrect and / or if only part of the transitions are executed, method 100 includes a step to identify 104 a leak of dihydrogen. Thus, in the example described, if the order of the first, second, third and fourth transitions carried out by the method is modified or if only part of the first, second, third and fourth transitions are executed, the process 100 includes a step of identifying 104 a defect in the execution of said method.

[0067] For example, if the method proceeds from a dihydrogen leak detection step n to a dihydrogen leak detection step n+2 or n+3 without going through the preceding dihydrogen leak detection step n+1, then a method execution fault is identified. Similarly, if only the first and second transitions are executed, then a method execution fault is identified.

[0068] When a leak is identified or a failure in the execution of the method is identified, the process 100 performs a step to degrade or prohibit 105 the operation of the fuel cell 3.

[0069] According to a limiting embodiment, the process 100 comprises a step of inhibiting 106 the step of degrading or prohibiting 105 the operation of the fuel cell 3, when • The method detects a dihydrogen leak and process 100 also detects a dihydrogen leak; • The method is interrupted by the activation of another method so that only part of the transitions are executed.

[0070] Indeed, when the leak is detected by the level 1 detection method, it is not necessary to activate the degraded operating mode or the fuel cell 3 shutdown provided for in method 100 according to the invention. The detection method can, for example, inform the driver that a leak has been detected without degrading the operation of the fuel cell 3.

[0071] Furthermore, the method is interrupted by the activation of another method so that only a portion of the first, second, third, and fourth transitions are executed when, for example, the vehicle is stationary, the detection method and the process according to the invention are activated, and then the driver inserts the hydrogen refueling nozzle into the vehicle's fuel filler flap. At this point, the detection method is stopped in favor of another detection method not executed by the vehicle's control means 11, but executed by the refueling station. The process 100 according to the invention then does not detect a leak.

Claims

1.

2. Demands Method (100) for verifying the results of a leak detection method in a hydrogen storage and supply circuit (2) of a fuel cell (3) of a vehicle (1), said method (100) being characterized in that, when said method is carried out, it comprises the steps, carried out by control means (11) of said vehicle (1), of: - Determine (101), during each step of detection of a dihydrogen leak of said method, an evolution of at least one parameter reflecting a dihydrogen leak in the dihydrogen storage and supply circuit (2); - Verify (102), with a state machine executed by said method, each transition passage from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by said method; - If said evolution of said at least parameter reflecting a determined leak is, according to at least one parameter, lower or higher than a threshold, identify (103) a dihydrogen leak; - If the order in which the transitions are executed is incorrect, or if only part of the transitions are executed, identify (104) a failure in the execution of said method. Method (100) according to the preceding claim, characterized in that for a dihydrogen storage and supply circuit (2) comprising: - One or more tank(s) (4), each tank being equipped with a first solenoid valve (5); - A first high-pressure circuit (6) connected to the first solenoid valve(s) (5) and to a second solenoid valve (7); - A second high-pressure circuit (8) connected to the second solenoid valve (7) and to a pressure regulator (9); and A medium-pressure circuit (10) connected to the pressure regulator (9) and the fuel cell (3); the step of determining (101) a change in at least one parameter reflecting a leak of dihydrogen in the dihydrogen storage and supply circuit (2) comprises the steps of: When, during a first step of the method for detecting a dihydrogen leak, each first solenoid valve (5) is closed and the fuel cell (3) is in operation, determine (1011) a change in at least one first parameter reflecting a dihydrogen leak in the first high-pressure circuit (6) or the second high-pressure circuit (8); When, during a second step of detecting a dihydrogen leak of said method, the first and second solenoid valves (5, 7) are closed and the fuel cell (3) is in operation, determine (1012) a change in at least a second parameter reflecting a dihydrogen leak in the second high-pressure circuit (8); When, during a third step of detecting a dihydrogen leak of said method, the first and second solenoid valves (5, 7) are closed and the operation of the fuel cell (3) is stopped, determine (1013) a change in at least a third parameter reflecting a dihydrogen leak in the first high-pressure circuit (6); When, during a fourth step of detecting a dihydrogen leak of said method, the first and second solenoid valves (5, 7) are closed and the operation of the fuel cell (3) is stopped, determine (1014) a change in at least a fourth parameter reflecting a dihydrogen leak in the second high-pressure circuit (8); A dihydrogen leak is identified if the evolution of at least one first, second, third, or fourth parameter reflecting a specific leak is, according to the...

3.

4. minus a first, second, third or fourth parameter, lower or higher than an associated threshold. Method (100) according to the preceding claim, characterized in that the step of verifying (102), with a state machine executed by the method, each transition from a dihydrogen leak detection step n to a dihydrogen leak detection step n+1 executed by said method comprises the steps of: - Verify (102i), with said state machine, a first transition from the first step of detecting a dihydrogen leak to the second step of detecting a dihydrogen leak executed by said method; - Verify (1022), with said state machine, a second transition from said second step of detecting a dihydrogen leak to the third step of detecting a dihydrogen leak executed by said method; - Verify (1023), with said state machine, a third transition from said third step of detection of a dihydrogen leak to the fourth step of detection of a dihydrogen leak executed by said method; - Verify (1024), with said state machine, a fourth transition from said fourth step of detecting a dihydrogen leak to a final dihydrogen leak detection step executed by said method; - A failure to execute said method is identified if the order of passage of the first, second, third and fourth transitions is incorrect or if only part of the first, second, third and fourth transitions are executed. Method (100) according to any one of claims 2 or 3, characterized in that when at least one first parameter is formed by: - A pressure of dihydrogen in the first high-pressure circuit (6), - A dihydrogen pressure in the second high-pressure circuit (8), and / or - Consumption of a first quantity of dihydrogen contained in the dihydrogen storage and supply circuit (2), - A leak is identified if: - The evolution of said dihydrogen pressure in the first high pressure circuit (6) is less than a first pressure threshold; - The evolution of said dihydrogen pressure in the second high pressure circuit (8) is less than a second pressure threshold; and / or - The evolution of said consumption of a first quantity of dihydrogen is less than a first consumption threshold.

5. A method (100) according to any one of claims 2 to 4, characterized in that when at least a second parameter is formed by: - ​​A pressure of dihydrogen in the second high-pressure circuit (8), and / or - A consumption of a second quantity of dihydrogen contained in the dihydrogen storage and supply circuit (2), - A leak is identified if: - The evolution of said dihydrogen pressure in the second high-pressure circuit (8) is less than a third pressure threshold; and / or - The evolution of said consumption of a second quantity of dihydrogen is less than a second consumption threshold.

6. A method (100) according to any one of claims 2 to 5, characterized in that when at least a third parameter is formed by: - ​​A time spent for the execution of the third step of detecting a dihydrogen leak of the method, - A pressure of the dihydrogen in the first high-pressure circuit (6), and / or - A temperature of the dihydrogen in the first high-pressure circuit (6), - A leak is identified if: - The evolution of the time spent for the execution of the third step of detection of a dihydrogen leak of the method is greater than a first time threshold; - The evolution of said pressure of the dihydrogen in the first high pressure circuit (6) is less than a fourth pressure threshold, and / or - The evolution of the temperature of the dihydrogen in the first high pressure circuit (6) is less than a first temperature threshold.

7. A method (100) according to any one of claims 2 to 6, characterized in that when at least a fourth parameter is formed by: - ​​A time spent for the execution of the fourth step of detecting a dihydrogen leak of the method, - A pressure of the dihydrogen in the second high-pressure circuit (8), and / or - A temperature of the dihydrogen in the second high-pressure circuit (8), - A leak is identified if: - The evolution of the time spent for the execution of the fourth step of detecting a dihydrogen leak of the method is greater than a second time threshold; and / or - The evolution of said pressure of the dihydrogen in the second high-pressure circuit (8) is less than a fifth pressure threshold, and / or - The evolution of the temperature of the dihydrogen in the second high-pressure circuit (8) is less than a second temperature threshold.

8. A method (100) according to any one of the preceding claims, characterized in that when a leak is detected, the method (100) includes a step of degrading or prohibiting (105) the operation of the fuel cell (3).

9. A method (100) according to the preceding claim, characterized in that it comprises a step of inhibiting (106) the step of degrading or prohibit (105) the operation of the fuel cell (3) when: - The method and the process (100) detect a leak of dihydrogen; - The method is interrupted by the activation of another method.

10. A motor vehicle (1) comprising a hydrogen storage and supply circuit (2) for a fuel cell (3) comprising: - One or more tank(s) (4), each tank being equipped with a first solenoid valve (5); - A first high-pressure circuit (6) connected to the first solenoid valve(s) (5) and to a second solenoid valve (7); - A second high-pressure circuit (8) connected to the second solenoid valve (7) and to a pressure regulator (9); - A medium-pressure circuit (10) connected to the pressure regulator (9) and to the fuel cell (3); - Said vehicle being characterized in that it comprises control means (11) arranged to carry out the steps of the process (100) according to any one of the preceding claims.

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