Fuel cell hydrogen leakage prediction method and system and vehicle

Abstract

The invention relates to a fuel cell hydrogen leakage prediction method and system and a vehicle, and the method comprises the steps: monitoring the current opening duration and the current opening time interval of a hydrogen proportional valve if a difference value between a current pressure value at a hydrogen inlet of an anode stack and a target pressure value is smaller than or equal to a preset value during the operation of a fuel cell system; calculating a first difference value between the current opening duration time and the opening duration time of the previous moment based on the current opening duration time and the current opening time interval of the hydrogen proportional valve, the opening duration time of the previous moment and the opening time interval of the previous moment; calculating a second difference value between the current opening time interval and the opening time interval of the previous moment; judging whether hydrogen leakage exists in the fuel cell system or not according to the first difference value and the second difference value, determining the hydrogen leakage level under the condition that hydrogen leakage exists in the fuel cell system, and performing grading treatment according to the hydrogen leakage level. A safe and effective treatment mode is adopted while hydrogen leakage is detected, and the cost of a fuel cell system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen leakage detection, in particular to a fuel cell hydrogen leakage prediction method, system and vehicle. BACKGROUND

[0002] Although the traditional hydrogen concentration sensor detection method has the basic advantages of simplicity and reliability, it has three core limitations in actual application, which are summarized as follows: (1) High cost: The tail hydrogen concentration sensor needs to adapt to a wide range of hydrogen concentration measurement scenarios and strict waterproof requirements, resulting in high manufacturing costs, which is not conducive to the overall cost optimization of the system; (2) Redundant design: The hydrogen concentration sensor of the tail and the hydrogen concentration sensor of the stack shell are both for internal hydrogen leakage detection, and the functions overlap, so there is no need for double configuration. A single tail hydrogen concentration sensor can achieve the internal leakage detection requirement, and the existing design causes resource waste; (3) Lack of robustness: When the hydrogen concentration sensor of the stack shell or the tail fails to communicate, the system lacks an effective fault tolerance mechanism and can only adopt a single processing method of emergency shutdown. In the fault state, it is easy to cause system misjudgment, affecting the stability and continuity of operation. SUMMARY

[0003] The present application provides a fuel cell hydrogen leakage prediction method, system and vehicle to solve the problems of high cost and single detection method of the traditional fuel cell system hydrogen concentration detection method, and easy misjudgment of the fuel cell system due to sensor communication failure.

[0004] The first aspect of the present application provides a fuel cell hydrogen leakage prediction method, comprising the following steps: detecting the current pressure value at the anode stack hydrogen inlet when the fuel cell system meets the preset operating conditions; if the difference between the current pressure value at the anode stack hydrogen inlet and the target pressure value is less than or equal to the preset value, monitoring the current opening duration and the current opening time interval of the hydrogen proportional valve; based on the current opening duration and the current opening time interval of the hydrogen proportional valve and the opening duration and the opening time interval at the last time, calculating the first difference between the current opening time interval and the opening time interval at the last time, and calculating the second difference between the current opening duration and the opening duration at the last time; determining whether the fuel cell system has hydrogen leakage according to the first difference and the second difference, determining the hydrogen leakage level when the fuel cell system has hydrogen leakage, and performing hierarchical processing according to the hydrogen leakage level.

[0005] Optionally, determining whether the fuel cell system has a hydrogen leak based on the first difference and the second difference, and determining the hydrogen leak level when the fuel cell system has a hydrogen leak, includes: if the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than a first proportion, then the fuel cell system has a hydrogen leak, and the hydrogen leak level is a first leak level; if the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first proportion, then the fuel cell system has a hydrogen leak based on the second difference.

[0006] Optionally, determining whether the fuel cell system has a hydrogen leak based on the second difference, and determining the hydrogen leak level when a hydrogen leak is determined to exist in the fuel cell system, includes: determining whether the ratio of the difference between the second difference and the second calibration value to the obtained second calibration value is greater than or equal to a second proportion; if the ratio of the difference between the second difference and the second calibration value to the obtained second calibration value is greater than or equal to the second proportion, then detecting the hydrogen concentration in the vehicle's power compartment; if the hydrogen concentration in the vehicle's power compartment is greater than a preset concentration value, then determining that the fuel cell system has a hydrogen leak, and the hydrogen leak level is a second leak level; if the hydrogen concentration in the power compartment is less than or equal to the preset concentration value, then determining that the fuel cell system has a hydrogen leak, and the hydrogen leak level is a third leak level.

[0007] Optionally, after determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, the method includes: if the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than the second proportion, then it is determined that there is no hydrogen leakage in the fuel cell system.

[0008] Optionally, the hydrogen leakage level is classified and processed, including: if the hydrogen leakage level of the fuel cell system is the first leakage level, then the fuel cell system is controlled to shut down urgently; if the hydrogen leakage level of the fuel cell system is the second leakage level, then the speed of the purge fan of the power compartment is increased to the first target speed, and the fuel cell system is controlled to shut down normally; if the hydrogen leakage level of the fuel cell system is the third leakage level, then the speed of the purge fan of the power compartment is increased to the second target speed, and the fuel cell system is controlled to operate at a reduced load.

[0009] Optionally, when the difference between the current pressure value at the hydrogen inlet of the anode stack and the corresponding target pressure value is greater than a preset value, the method includes controlling the fuel cell system to perform a load shedding shutdown.

[0010] Optionally, the preset operating conditions are that the fuel cell system is turned on, the current density of the fuel cell system is greater than or equal to the preset current density, and the proportional valve of the hydrogen supply system is adjusted to the target position.

[0011] A second aspect of this application provides a fuel cell hydrogen leakage prediction system, comprising: a pressure detection module for detecting the current pressure value at the hydrogen inlet of the anode stack when the fuel cell system meets preset operating conditions; a data detection module for monitoring the current opening duration and current opening time interval of a hydrogen proportional valve if the difference between the current pressure value and the target pressure value at the hydrogen inlet of the anode stack is less than or equal to a preset value; a hydrogen leakage detection module for calculating a first difference between the current opening time interval and the previous opening time interval based on the current opening duration and the current opening time interval of the hydrogen proportional valve and the opening duration and the previous opening time interval of the previous moment, and calculating a second difference between the current opening duration and the previous opening duration; and a processing module for determining whether there is a hydrogen leakage in the fuel cell system based on the first difference and the second difference, determining the hydrogen leakage level when a hydrogen leakage is determined in the fuel cell system, and performing graded processing based on the hydrogen leakage level.

[0012] Optionally, the hydrogen leak detection module is further configured to: if the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than a first proportion, then determine that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is a first leak level; if the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first proportion, then determine whether there is a hydrogen leak in the fuel cell system based on the second difference.

[0013] Optionally, the hydrogen leak detection module is further configured to: determine whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to a second proportion; if the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, then detect the hydrogen concentration in the power compartment of the vehicle; if the hydrogen concentration in the power compartment of the vehicle is greater than a preset concentration value, then determine that the fuel cell system has a hydrogen leak, and the hydrogen leak level is a second leak level; if the hydrogen concentration in the power compartment is less than or equal to the preset concentration value, then determine that the fuel cell system has a hydrogen leak, and the hydrogen leak level is a third leak level.

[0014] Optionally, after determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, the hydrogen leakage detection module is further configured to: if the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than the second proportion, then determine that there is no hydrogen leakage in the fuel cell system.

[0015] Optionally, the processing module is configured to: if the hydrogen leakage level of the fuel cell system is a first leakage level, control the fuel cell system to shut down urgently; if the hydrogen leakage level of the fuel cell system is a second leakage level, increase the speed of the purge fan of the power compartment to a first target speed and control the fuel cell system to shut down normally; if the hydrogen leakage level of the fuel cell system is a third leakage level, increase the speed of the purge fan of the power compartment to a second target speed and control the fuel cell system to operate at a reduced load.

[0016] Optionally, when the difference between the current pressure value at the hydrogen inlet of the anode stack and the corresponding target pressure value is greater than a preset value, the pressure detection module is further configured to: control the fuel cell system to perform a load shedding shutdown.

[0017] Optionally, the preset operating conditions are that the fuel cell system is turned on, the current density of the fuel cell system is greater than or equal to the preset current density, and the proportional valve of the hydrogen supply system is adjusted to the target position.

[0018] A third aspect of this application provides a vehicle comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the fuel cell hydrogen leakage prediction method as described in the above embodiments.

[0019] A fourth aspect of this application provides a computer program product having a computer program stored thereon, which is executed by a processor to implement the fuel cell hydrogen leakage prediction method as described in the above embodiments.

[0020] In the above embodiments, when the fuel cell system meets preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected. If the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, the current opening duration and current opening time interval of the hydrogen proportional valve are monitored. Based on the current opening duration and current opening time interval of the hydrogen proportional valve and the opening duration and opening time interval of the previous moment, a first difference between the current opening time interval and the opening time interval of the previous moment is calculated, and a second difference between the current opening duration and the opening duration of the previous moment is calculated. The presence of hydrogen leakage in the fuel cell system is determined based on the first and second differences. If hydrogen leakage is determined, the hydrogen leakage level is determined, and graded processing is performed according to the hydrogen leakage level. This solves the problems of high cost, single detection method, and susceptibility to misjudgment of the fuel cell system due to sensor communication failures in traditional fuel cell system hydrogen concentration detection methods. It eliminates multiple sensors in the system, and simultaneously detects hydrogen leakage while implementing a safe and effective fuel cell system shutdown method, reducing the overall cost and economy of the fuel cell system.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a fuel cell hydrogen leakage prediction method provided according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a fuel cell system provided according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating the principle of hydrogen leakage prediction based on state parameters according to an embodiment of this application; Figure 4 This is a schematic diagram showing the positions of the power compartment and hydrogen concentration sensor according to an embodiment of this application; Figure 5 This is a flowchart of a fuel cell hydrogen leakage prediction method provided according to an embodiment of this application; Figure 6 This is a schematic diagram of a fuel cell hydrogen leakage prediction system according to an embodiment of this application; Figure 7 This is a schematic diagram of a vehicle structure according to an embodiment of this application. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] To address the problems mentioned in the background art regarding the high cost, limited detection methods, and susceptibility to misjudgments caused by sensor communication failures in traditional fuel cell system hydrogen concentration detection methods, this application provides a fuel cell hydrogen leakage prediction method. In this method, when the fuel cell system meets preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected. If the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, the current opening duration and current opening time interval of the hydrogen proportional valve are monitored. Based on the current opening duration and current opening time interval of the hydrogen proportional valve, and the opening duration and opening time interval of the previous moment, a first difference between the current opening time interval and the previous opening time interval are calculated, and a second difference between the current opening duration and the previous opening duration are calculated. The presence of hydrogen leakage in the fuel cell system is determined based on the first and second differences. If hydrogen leakage is determined, the hydrogen leakage level is determined, and the process is graded according to the hydrogen leakage level. This solves the problems of high cost, single detection method, and easy misjudgment of fuel cell system due to sensor communication failure in traditional hydrogen concentration detection methods. It eliminates multiple sensors in the system and takes safe and effective measures to shut down the fuel cell system while detecting hydrogen leakage, thereby reducing the overall cost and economy of the fuel cell system.

[0025] Common market solutions primarily focus on hydrogen concentration detection in the fuel cell stack casing, system gas emissions, and vehicle power compartment. However, these three methods operate at different stages. The fuel cell stack casing hydrogen concentration sensor mainly predicts hydrogen leakage from the membrane electrode assembly (MEA) and bipolar plate channels to the outside of the stack. Once this leakage occurs, it can be quickly detected by the casing hydrogen concentration sensor, triggering a system-wide fault that limits power output or shuts down the system. The system exhaust hydrogen concentration sensor detects hydrogen leakage primarily from hydrogen purging the fuel cell stack casing and hydrogen escaping when the anode drain and nitrogen purging valves are open. If the drain and nitrogen purging valves fail, hydrogen leakage from the anode can be quickly detected by the exhaust hydrogen concentration sensor, prompting the system to reduce power or shut down immediately.

[0026] The hydrogen concentration sensor in the engine compartment has a wider detection range, mainly detecting hydrogen leaks at the sealing points of the anode path, such as leaks in the anode manifold, leaks in the anode hydrogen connection pipe, and hydrogen leaks at all anode seals. Hydrogen leaks that accumulate at these locations may enter the cockpit with the air conditioning recirculation, so sensor detection of hydrogen leaks at this location is essential.

[0027] Specifically, Figure 1 This is a schematic flowchart of a fuel cell hydrogen leakage prediction method provided in an embodiment of this application.

[0028] like Figure 1 As shown, the fuel cell hydrogen leakage prediction method includes the following steps: In step S101, when the fuel cell system meets the preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected.

[0029] Optionally, in some embodiments, when the difference between the current pressure value at the hydrogen inlet of the anode stack and the corresponding target pressure value is greater than a preset value, the method includes controlling the fuel cell system to perform a load shedding shutdown.

[0030] Optionally, in some embodiments, the preset operating conditions are that the fuel cell system is turned on, the current density of the fuel cell system is greater than or equal to the preset current density, and the proportional valve of the hydrogen supply system is adjusted to the target position.

[0031] Specifically, the structure of the fuel cell system is as follows: Figure 2 As shown, the fuel cell system completes the start-up state and power load state machine jump according to the system request, and completes key start-up steps such as start-up purging. The power is current-loaded to a fixed current density condition. The proportional valve of the hydrogen supply system is adjusted to the target position (set by those skilled in the art). According to the operating conditions, the system controller records the current pressure value at the hydrogen inlet of the anode stack and performs signal filtering to obtain a stable value, that is, the current pressure value at the hydrogen inlet of the anode stack.

[0032] In step S102, if the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, the current opening duration and the current opening time interval of the hydrogen proportional valve are monitored.

[0033] The target pressure value and the preset value can be thresholds set by the user, thresholds obtained through a limited number of experiments, or thresholds obtained through a limited number of computer simulations; no specific limitations are imposed here.

[0034] Determine the current current density and compare the current pressure value at the hydrogen inlet of the anode stack with the target pressure value at that current density. If the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value (e.g., 5 kPa), record the opening duration and opening time interval of the hydrogen proportional valve.

[0035] If the current pressure at the hydrogen inlet of the anode stack is greater than the target pressure at that current density than the preset value (e.g., 5 kPa), it is determined that there is a defect in the fuel cell system seal, the system enters the shutdown purging state, and shutdown is performed.

[0036] In step S103, based on the current opening duration and the current opening time interval of the hydrogen proportional valve and the opening duration and the opening time interval of the previous moment, a first difference between the current opening time interval and the opening time interval of the previous moment is calculated, and a second difference between the current opening duration and the opening duration of the previous moment is calculated.

[0037] It should be noted that both the first and second differences are output in absolute value form.

[0038] Specifically, the schematic diagram of the hydrogen leak prediction principle is as follows: Figure 3 As shown. First, determine the opening duration t1 and opening time interval t2 of the nitrogen purging valve (the opening duration is the duration after the valve is opened, and the opening interval is the interval between openings, which is generally determined by calibrating the fuel cell with different operating current densities on a test bench. For example, record the time when the nitrogen purging valve operates once, and record the time when it operates again. The difference between the two recorded times is t2). Record the opening interval t3 and the opening duration t4 of the hydrogen proportional valve. Form a time matrix [t1, t2, t3, t4] from t1, t2, t3, and t4.

[0039] Keeping the opening duration t1 and opening time interval t2 of the nitrogen venting valve unchanged, the current opening duration t'4 and current opening time interval t'3 ​​of the hydrogen proportional valve are collected.

[0040] Based on the previous opening duration t4 and the current opening duration t'4, as well as the previous opening time interval t3 and the current opening time interval t'3, calculate the first difference Δt3 based on the previous opening time interval t3 and the current opening time interval t'3, and calculate the second difference Δt4 based on the previous opening duration t4 and the current opening duration t'4.

[0041] In step S104, the presence of hydrogen leakage in the fuel cell system is determined based on the first difference and the second difference. If hydrogen leakage is determined to exist in the fuel cell system, the hydrogen leakage level is determined, and the hydrogen leakage level is classified and processed accordingly.

[0042] Furthermore, in some embodiments, determining whether there is a hydrogen leak in the fuel cell system based on a first difference and a second difference, and determining the hydrogen leak level when a hydrogen leak is determined in the case of a hydrogen leak in the fuel cell system, includes: if the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than a first proportion, then determining that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is the first leak level; if the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first proportion, then determining whether there is a hydrogen leak in the fuel cell system based on the second difference.

[0043] Optionally, in some embodiments, determining whether there is a hydrogen leak in the fuel cell system based on the second difference includes: determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to a second proportion; if the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, then detecting the hydrogen concentration in the vehicle's power compartment; if the hydrogen concentration in the vehicle's power compartment is greater than a preset concentration value, then determining that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is a second leak level; if the hydrogen concentration in the power compartment is less than or equal to the preset concentration value, then determining that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is a third leak level.

[0044] The powertrain compartment is located below the driver's cab. It is not completely sealed; basic waterproofing and dustproofing are achieved through sealing strips and dustproof netting. Ventilation vents are provided to connect to the vehicle's air duct system. The fuel cell system is housed within the powertrain compartment. Hydrogen concentration in the compartment is collected by a hydrogen concentration sensor located at the top of the compartment. The positions of the powertrain compartment and the hydrogen concentration sensor are as follows: Figure 4 As shown.

[0045] It should be noted that the first leakage level is greater than the second leakage level, and the second leakage level is greater than the third leakage level. Specifically, the first leakage level indicates a serious hydrogen leak in the fuel cell system, the second leakage level indicates a moderate hydrogen leak in the fuel cell system, and the third leakage level indicates a minor hydrogen leak in the fuel cell system.

[0046] The first calibration value and the second calibration value, the first ratio and the second ratio can be thresholds preset by the user, thresholds obtained through a limited number of experiments, or thresholds obtained through a limited number of computer simulations. No specific limitation is made here. This application uses 10% as an example for illustration.

[0047] The first difference Δt3 between the previous start-up time interval t3 and the current start-up time interval t'3 ​​is compared with the first calibration value a. If the ratio of the first difference Δt3 to the first calibration value a is greater than the first proportion, i.e. (Δt3-a) / a is greater than 10%, then it is determined that a serious hydrogen leak has occurred in the fuel cell system.

[0048] If the ratio of the difference between the first difference Δt3 and the first calibration value a to the first calibration value is less than or equal to the first proportion, i.e. (Δt3-a) / a≤10%, then the degree of leakage in the fuel cell system needs to be further determined.

[0049] At this point, the absolute value (Δt4-b) of the difference between the previous activation duration t4 and the current activation duration t'4 is compared with the second calibration value b. If the ratio of the second difference to the second calibration value Δt4 is greater than the second proportion, i.e. (Δt4-b) / b is greater than or equal to 10%, the system reads the hydrogen concentration sensor value in the power compartment. If the hydrogen concentration in the power compartment is greater than 1%, it is determined that there is a moderate hydrogen leak in the fuel cell system.

[0050] If the hydrogen concentration in the power compartment is less than or equal to 1%, it is determined that the vehicle's fuel cell system has a slight hydrogen leak or that the engine anode circuit has a sealing failure (generally, there is a sealing failure in the anode manifold, hydrogen pump, gas-water separator, etc., with a small amount of hydrogen escaping).

[0051] Optionally, in some embodiments, after determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, the method includes: if the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than the second proportion, then it is determined that there is no hydrogen leakage in the fuel cell system.

[0052] It is understandable that if the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than 10%, that is, (Δt4-b) / b is less than or equal to 10%, then the fuel cell system is determined to have no leakage.

[0053] Optionally, in some embodiments, the hydrogen leakage level is graded, including: if the hydrogen leakage level of the fuel cell system is the first leakage level, then the fuel cell system is controlled to shut down urgently; if the hydrogen leakage level of the fuel cell system is the second leakage level, then the speed of the purge fan of the power compartment is increased to the first target speed, and the fuel cell system is controlled to shut down normally; if the hydrogen leakage level of the fuel cell system is the third leakage level, then the speed of the purge fan of the power compartment is increased to the second target speed, and the fuel cell system is controlled to operate at a reduced load.

[0054] The first target rotational speed and the second target rotational speed can be thresholds preset by the user, thresholds obtained through a limited number of experiments, or thresholds obtained through a limited number of computer simulations; no specific limitations are imposed here.

[0055] Specifically, if the hydrogen leakage level of the fuel cell system is the first leakage level, then the fuel cell system will be shut down immediately. If the hydrogen leakage level of the fuel cell system is the second leakage level, increase the speed of the purge fan in the power compartment to the first target speed and control the fuel cell system to shut down normally.

[0056] If the hydrogen leakage level of the fuel cell system is level three, increase the speed of the purge fan in the power compartment to the second target speed, and control the fuel cell system to operate under reduced load to support partial power output of the vehicle. If instrument malfunction lights illuminate, the vehicle will be driven to the nearest service station for repair.

[0057] In the absence of leaks in the fuel cell system, the opening interval and duration of the hydrogen proportional valve are continuously monitored, and hydrogen leak detection is performed based on the opening interval and duration of the hydrogen proportional valve.

[0058] To enable those skilled in the art to further understand the fuel cell hydrogen leakage prediction method of the embodiments of this application, the following detailed description is provided in conjunction with specific embodiments, such as... Figure 5 As shown.

[0059] Step 1: The fuel cell system completes the power-on / off state and power-load state machine transitions according to the system request, and completes key startup steps such as startup purging.

[0060] Step 2: Apply current to the power supply system until a fixed current density is reached, and adjust the proportional valve of the hydrogen supply system to the appropriate position.

[0061] Step 3: Based on the operating conditions, the system controller records the current pressure value at the hydrogen inlet of the anode stack and performs signal filtering to obtain a stable value.

[0062] Step 4: Compare the stabilized pressure value with the target pressure value under the current density condition to see if there is a large deviation (more than 5 kPa). If the pressure value cannot be maintained at the normal value, then there is a defect in the system seal. The system should enter the shutdown purging state and be shut down.

[0063] Step 5: If the hydrogen pressure at the fuel cell stack inlet is normal, monitor the system in real time and record the status of the system's nitrogen venting valve.

[0064] Step 6: The system records the opening duration t1 and opening time interval t2 of the nitrogen venting valve, the opening time interval t3 of the hydrogen proportional valve, and the opening duration t4 of the hydrogen proportional valve. The system then forms a time matrix [t1, t2, t3, t4] from t1, t2, t3, and t4.

[0065] Step 7: Keep t1 and t2 unchanged, record the opening time interval t3 and opening duration t4 of the previous moment, and the current opening time interval t'3 ​​and opening duration t'4. Then, calculate the difference between the real-time updated values ​​and output the difference in the form of absolute value.

[0066] Step 8: Compare the difference Δt3 between t3 and t'3 with the calibrated value a. If (Δt3-a) / a is greater than 10%, it is determined that a serious hydrogen leak has occurred in the system, and the system is handled by emergency shutdown.

[0067] Step 9: If (Δt3-a) / a is less than 10%, the degree of leakage in the system needs to be further determined. At this time, the absolute value of the difference between t4 and t'4 (Δt4) is compared with the calibration value b. If (Δt4-b) / b is less than 10%, the system enters step 5 and enters the next detection cycle.

[0068] Step 10: If (Δt4-b) / b is greater than or equal to 10%, the system reads the value of the hydrogen concentration sensor in the power compartment. If the hydrogen concentration value exceeds 1%, it is determined that there is a moderate leak in the system. The system will increase the speed of the purge fan in the power compartment, and the fuel cell system will enter the normal load reduction and shutdown stage.

[0069] Step 11: If the hydrogen concentration value does not exceed 1%, it is determined that there is a slight leak in the system or a sealing failure in the engine anode circuit (generally, there is a sealing failure in the anode manifold, hydrogen pump, gas-water separator, etc., with a small amount of hydrogen escaping). The system will increase the speed of the power compartment purge fan, the fuel cell system will reduce the load, support part of the vehicle's power output, the instrument fault light will illuminate, and the vehicle will be driven to the nearest service station for repair.

[0070] According to the fuel cell hydrogen leakage prediction method proposed in this application embodiment, when the fuel cell system meets preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected; if the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, the current opening duration and the current opening time interval of the hydrogen proportional valve are monitored; based on the current opening duration and the current opening time interval of the hydrogen proportional valve and the opening duration and the opening time interval of the previous moment, a first difference between the current opening time interval and the opening time interval of the previous moment is calculated, and a second difference between the current opening duration and the opening duration of the previous moment is calculated; the presence of hydrogen leakage in the fuel cell system is determined based on the first difference and the second difference; if hydrogen leakage is determined in the fuel cell system, the hydrogen leakage level is determined, and the hydrogen leakage level is graded accordingly. Therefore, when hydrogen leaks in the fuel cell system, the system effectively compensates for the pressure in the hydrogen chamber. Depending on the degree of compensation, the extent of hydrogen leakage can be distinguished. Furthermore, the severity of the hydrogen leak can be predicted based on the compensation frequency and duration of the hydrogen proportional valve during the leak. Combined with the hydrogen concentration sensor in the power compartment for closed-loop monitoring, the exhaust hydrogen concentration sensor and stack housing sensor in the system can be eliminated. This allows for the detection of hydrogen leaks while also implementing safe and effective shutdown methods for the fuel cell system. The saved hardware will further reduce the overall cost and economic efficiency of the fuel cell system.

[0071] Next, with reference to the accompanying drawings, a fuel cell hydrogen leakage prediction system according to an embodiment of this application is described.

[0072] Figure 6 This is a block diagram of a fuel cell hydrogen leakage prediction system according to an embodiment of this application.

[0073] like Figure 6 As shown, the fuel cell hydrogen leakage prediction system 10 includes: a pressure detection module 100, a data detection module 200, a hydrogen leakage detection module 300, and a processing module 400.

[0074] The system includes the following components: a pressure detection module 100, used to detect the current pressure value at the hydrogen inlet of the anode stack when the fuel cell system meets preset operating conditions; a data detection module 200, used to monitor the current opening duration and current opening time interval of the hydrogen proportional valve if the difference between the current pressure value and the target pressure value at the hydrogen inlet of the anode stack is less than or equal to a preset value; a hydrogen leakage detection module 300, used to calculate a first difference between the current opening time interval and the previous opening time interval based on the current opening duration and the current opening time interval of the hydrogen proportional valve, and a second difference between the current opening duration and the previous opening time interval; and a processing module 400, used to determine whether there is a hydrogen leak in the fuel cell system based on the first and second differences, determine the hydrogen leak level if a hydrogen leak is determined, and perform graded processing according to the hydrogen leak level.

[0075] Optionally, in some embodiments, the hydrogen leakage detection module 300 is configured to: determine the hydrogen leakage level as the first leakage level if the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than a first proportion; and determine whether there is a hydrogen leakage in the fuel cell system based on the second difference if the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first proportion.

[0076] Optionally, in some embodiments, the hydrogen leak detection module 300 is used to: determine whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to a second proportion; if the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, then detect the hydrogen concentration in the vehicle's power compartment; if the hydrogen concentration in the vehicle's power compartment is greater than a preset concentration value, then determine that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is a second leak level; if the hydrogen concentration in the power compartment is less than or equal to the preset concentration value, then determine that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is a third leak level.

[0077] Optionally, in some embodiments, after determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second proportion, the hydrogen leakage detection module 300 is configured to: if the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than the second proportion, then determine that there is no hydrogen leakage in the fuel cell system.

[0078] Optionally, in some embodiments, the processing module 400 is configured to: if the hydrogen leakage level of the fuel cell system is a first leakage level, control the fuel cell system to shut down urgently; if the hydrogen leakage level of the fuel cell system is a second leakage level, increase the speed of the purge fan of the power compartment to a first target speed and control the fuel cell system to shut down normally; if the hydrogen leakage level of the fuel cell system is a third leakage level, increase the speed of the purge fan of the power compartment to a second target speed and control the fuel cell system to operate at a reduced load.

[0079] Optionally, in some embodiments, when the difference between the current pressure value at the hydrogen inlet of the anode stack and the corresponding target pressure value is greater than a preset value, the pressure detection module 100 is used to control the fuel cell system to perform a load shedding shutdown.

[0080] Optionally, in some embodiments, the preset operating conditions are that the fuel cell system is turned on, the current density of the fuel cell system is greater than or equal to the preset current density, and the proportional valve of the hydrogen supply system is adjusted to the target position.

[0081] It should be noted that the foregoing explanation of the embodiment of the fuel cell hydrogen leakage prediction method also applies to the fuel cell hydrogen leakage prediction system of this embodiment, and will not be repeated here.

[0082] According to the fuel cell hydrogen leakage prediction system proposed in this application, when the fuel cell system meets preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected. If the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, the current opening duration and current opening time interval of the hydrogen proportional valve are monitored. Based on the current opening duration and current opening time interval of the hydrogen proportional valve and the opening duration and opening time interval of the previous moment, a first difference between the current opening time interval and the opening time interval of the previous moment is calculated, and a second difference between the current opening duration and the opening duration of the previous moment is calculated. The presence of hydrogen leakage in the fuel cell system is determined based on the first difference and the second difference. If hydrogen leakage is determined to exist in the fuel cell system, the hydrogen leakage level is determined, and graded processing is performed according to the hydrogen leakage level. This solves the problems of high cost, single detection method, and easy misjudgment of the fuel cell system due to sensor communication failure in traditional fuel cell system hydrogen concentration detection methods. It eliminates multiple sensors in the system, and simultaneously detects hydrogen leakage while taking a safe and effective fuel cell system shutdown approach, reducing the overall cost and economy of the fuel cell system.

[0083] Figure 7 A schematic diagram of the structure of a vehicle provided in an embodiment of this application. The vehicle may include: The memory 701, the processor 702, and the computer program stored in the memory 701 and capable of running on the processor 702.

[0084] When the processor 702 executes the program, it implements the fuel cell hydrogen leakage prediction method provided in the above embodiments.

[0085] Furthermore, the vehicle also includes: Communication interface 703 is used for communication between memory 701 and processor 702.

[0086] The memory 701 is used to store computer programs that can run on the processor 702.

[0087] The memory 701 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0088] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0089] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0090] The processor 702 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0091] This application also provides a computer program product on which a computer program is stored, which, when executed by a processor, implements the above-described fuel cell hydrogen leakage prediction method.

[0092] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0093] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0094] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0095] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable instructions for implementing logical functions, and can be specifically implemented in any computer program product for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer program product" can be any means that can contain, store, communicate, propagate, or transmit a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples of computer program products (a non-exhaustive list) include the following: an electrical connection having one or N wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic device, and portable optical disc read-only memory (CDROM). Furthermore, the computer program product can even be paper or other suitable medium on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0096] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0097] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer program product, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0098] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer program product.

[0099] The computer program product mentioned above may be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for predicting hydrogen leakage in a fuel cell, characterized in that, Includes the following steps: When the fuel cell system meets the preset operating conditions, the current pressure value at the hydrogen inlet of the anode stack is detected; If the difference between the current pressure value at the hydrogen inlet of the anode stack and the target pressure value is less than or equal to a preset value, then monitor the current opening duration and the current opening time interval of the hydrogen proportional valve. Based on the current opening duration and current opening time interval of the hydrogen proportional valve, and the opening duration and opening time interval of the previous moment, calculate the first difference between the current opening time interval and the opening time interval of the previous moment, and calculate the second difference between the current opening duration and the opening duration of the previous moment. The presence of hydrogen leakage in the fuel cell system is determined based on the first difference and the second difference. If hydrogen leakage is found in the fuel cell system, the hydrogen leakage level is determined, and the hydrogen leakage is classified and processed according to the hydrogen leakage level.

2. The method according to claim 1, characterized in that, The step of determining whether the fuel cell system has hydrogen leakage based on the first difference and the second difference includes: If the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than the first proportion, then the hydrogen leakage level is determined to be the first leakage level; If the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first ratio, then the presence of hydrogen leakage in the fuel cell system is determined based on the second difference.

3. The method according to claim 2, characterized in that, The step of determining whether there is hydrogen leakage in the fuel cell system based on the second difference includes: Determine whether the ratio of the second difference and the second calibration value to the second calibration value is greater than or equal to the second ratio; If the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second ratio, then the hydrogen concentration in the vehicle's power compartment is detected. If the hydrogen concentration in the power compartment of the vehicle is greater than a preset concentration value, it is determined that the fuel cell system has a hydrogen leak, and the hydrogen leak level is the second leak level. If the hydrogen concentration in the power compartment is less than or equal to the preset concentration value, it is determined that the fuel cell system has a hydrogen leak, and the hydrogen leak level is the third leak level.

4. The method according to claim 3, characterized in that, After determining whether the ratio of the difference between the second difference and the second calibration value to the second calibration value is greater than or equal to the second ratio, the process includes: If the ratio of the difference between the second difference and the second calibration value to the second calibration value is less than the second ratio, then it is determined that there is no hydrogen leakage in the fuel cell system.

5. The method according to claim 3, characterized in that, The hydrogen leakage level is classified and handled accordingly, including: If the hydrogen leakage level of the fuel cell system is the first leakage level, then control the fuel cell system to shut down urgently; If the hydrogen leakage level of the fuel cell system is the second leakage level, then increase the speed of the purge fan of the power compartment to the first target speed and control the fuel cell system to shut down normally. If the hydrogen leakage level of the fuel cell system is the third leakage level, then the speed of the purge fan of the power compartment is increased to the second target speed, and the fuel cell system is controlled to operate at a reduced load.

6. The method according to claim 1, characterized in that, When the difference between the current pressure value at the hydrogen inlet of the anode stack and the corresponding target pressure value is greater than a preset value, including: Control the fuel cell system to perform a load shedding and shutdown.

7. The method according to claim 1, characterized in that, The preset operating conditions are that the fuel cell system is turned on, the current density of the fuel cell system is greater than or equal to the preset current density, and the proportional valve of the hydrogen supply system is adjusted to the target position.

8. A fuel cell hydrogen leakage prediction system, characterized in that, include: The pressure detection module is used to detect the current pressure value at the hydrogen inlet of the anode stack when the fuel cell system meets the preset operating conditions; The data detection module is used to monitor the current opening duration and current opening time interval of the hydrogen proportional valve if the difference between the current pressure value and the target pressure value at the hydrogen inlet of the anode stack is less than or equal to a preset value. The hydrogen leakage detection module is used to calculate a first difference between the current opening time interval and the previous opening time interval based on the current opening duration and the current opening time interval of the hydrogen proportional valve and the opening duration and the previous opening time interval of the previous moment, and to calculate a second difference between the current opening duration and the previous opening duration. The processing module is used to determine whether there is a hydrogen leak in the fuel cell system based on the first difference and the second difference, determine the hydrogen leak level if a hydrogen leak is determined in the fuel cell system, and perform graded processing based on the hydrogen leak level.

9. The system according to claim 8, characterized in that, The hydrogen leak detection module is used for: If the ratio of the difference between the first difference and the first calibration value to the first calibration value is greater than the first proportion, then it is determined that there is a hydrogen leak in the fuel cell system, and the hydrogen leak level is the first leak level. If the ratio of the difference between the first difference and the first calibration value to the first calibration value is less than or equal to the first ratio, then the presence of hydrogen leakage in the fuel cell system is determined based on the second difference.

10. A vehicle, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the fuel cell hydrogen leakage prediction method as described in any one of claims 1-7.

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