Anode exhaust valve control method for fuel cell engine

Abstract

The present invention provides an anode exhaust valve control method for a fuel cell engine, which belongs to the field of fuel cell technology and solves the problem that the existing technology fails to effectively evaluate the nitrogen permeation rate of the proton exchange membrane for the exhaust opening strategy. The method comprises: S1. obtaining the total operating time of the fuel cell and obtaining the nitrogen permeability coefficient of the proton exchange membrane in the stack; S2. obtaining the flow rate, temperature, pressure and humidity of the tail gas on the cathode side and the anode side of the stack, respectively, and combining the nitrogen permeability coefficient to obtain the cumulative nitrogen concentration on the anode side of the stack; S3. identifying whether the above-mentioned nitrogen cumulative concentration exceeds the threshold value. If so, open the anode exhaust valve and execute step S4; otherwise, return to step S1; S4. obtain the gas pressure before and after the anode exhaust valve of the stack and obtain the gas flow rate of the anode of the stack. When it is identified that the gas flow rate is greater than the nitrogen cumulative concentration, close the anode exhaust valve and execute step S1; otherwise, maintain the state of the anode exhaust valve unchanged.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a method for controlling an anode exhaust valve of a fuel cell engine. Background Art

[0002] Fuel cell engine hydrogen supply systems typically utilize a hydrogen circulation model. During this process, nitrogen and water vapor in the cathode air diffuse through the proton exchange membrane to the anode. This can cause a decrease in hydrogen partial pressure over extended fuel cell operation. This localized hydrogen starvation can cause a drop in stack voltage and even electrochemical corrosion of the membrane electrode, leading to irreversible degradation of stack performance. Therefore, during operation, the exhaust valve must be intermittently opened to purge impurities, nitrogen, and water from the anode.

[0003] At present, the opening strategy of the engine exhaust valve is mostly a fixed time cycle strategy, for example, a 4-second cycle, and opening for 1 second in each cycle. This does not take into account the changes in membrane permeation characteristics caused by long-term operation of the fuel cell, and the changes in gas permeation rate caused by changes in the performance of the fuel cell stack.

[0004] Chinese patent application number CN202211235770.5 uses a voltage drop threshold or voltage dispersion to determine the level of nitrogen accumulation, thereby controlling the opening of the exhaust valve to discharge the accumulated nitrogen in the system. However, single-chip voltage determination is prone to misjudgment, resulting in poor control effectiveness.

[0005] The Chinese patent application number CN201710992471.9 uses a neural network algorithm to estimate the nitrogen concentration in the next cycle to adjust the opening frequency of the exhaust valve. However, there is no negative feedback as a judgment basis or for correcting the judgment, which can easily lead to misjudgment. At the same time, the model does not consider the impact of various factors such as temperature and pressure on nitrogen permeation and nitrogen accumulation.

[0006] The Chinese patent application number CN200810144696.X implements an exhaust valve opening strategy by controlling the exhaust valve flow rate and the expected flow rate, thereby avoiding the waste of hydrogen. However, there is no detailed explanation of the exhaust valve activation strategy, which is still in the research stage. Summary of the Invention

[0007] In view of the above analysis, an embodiment of the present invention aims to provide an anode exhaust valve control method for a fuel cell engine to solve the problem that the prior art fails to effectively evaluate the nitrogen permeation rate of the proton exchange membrane for exhaust opening strategy.

[0008] In one aspect, an embodiment of the present invention provides a method for controlling an anode exhaust valve of a fuel cell engine, comprising the following steps:

[0009] S1. Get the ambient temperature Tamb , total fuel cell operating time t 总 , input into the pre-calibrated nitrogen diffusion model to obtain the nitrogen permeability coefficient of the proton exchange membrane in the fuel cell stack;

[0010] S2. Obtain the current flow rate, temperature, pressure, and humidity of the tail gas on the cathode and anode sides of the stack, respectively, and calculate the cumulative nitrogen concentration on the anode side of the stack based on the nitrogen permeability coefficient;

[0011] S3. Identify whether the cumulative concentration of nitrogen on the anode side exceeds the set concentration threshold. If so, open the anode exhaust valve and execute step S4. Otherwise, return to step S1.

[0012] S4. Obtain the gas pressures at the front and rear ends of the stack anode exhaust valve respectively, and then determine the gas flow rate of the stack anode, and identify whether the gas flow rate is greater than the accumulated nitrogen concentration on the anode side. If so, close the anode exhaust valve and execute step S1; otherwise, maintain the state of the anode exhaust valve unchanged.

[0013] The beneficial effects of this technical solution are as follows: The nitrogen permeation rate of the proton exchange membrane is estimated using the membrane's nitrogen permeability coefficient, which serves as the basis for determining when to open the anode exhaust valve. This allows for precise control of the opening and closing of the anode exhaust valve in a fuel cell engine. Over extended fuel cell engine operation, the membrane's permeation rate can shift, causing variations in the nitrogen permeation and accumulation rates. This strategy enables dynamic regulation over a longer timescale.

[0014] Based on further improvements to the above device, step S1 obtains the nitrogen permeability coefficient λ of the proton exchange membrane in the stack through the nitrogen diffusion model in the following formula:

[0015]

[0016] in,

[0017]

[0018] The range of t is 0→t 总 , where κ is the coefficient of variation of the membrane electrode over time, is the nitrogen mole fraction on the anode side, t is the time, is the nitrogen constant, T is the normal operating temperature of the stack, P a is the hydrogen tail gas pressure on the anode side, S is the effective area of ​​the single cell of the stack, V is the cavity volume of the stack anode, P c is the air exhaust pressure on the cathode side, E N 2 is the enthalpy of nitrogen, ξ is the water content in the membrane, V dis the volume of the dry film, V w is the volume of the wet film.

[0019] Furthermore, step S2 further includes:

[0020] S21 obtains the current moment of the cathode side of the stack air exhaust flow, temperature, pressure and humidity;

[0021] S22 obtains the current moment of the anode side of the stack hydrogen exhaust flow, temperature, pressure and humidity;

[0022] S23. Input the above-mentioned cathode side air exhaust flow, temperature, pressure and humidity, anode side hydrogen exhaust flow, temperature, pressure and humidity, and nitrogen permeability coefficient into the pre-calibrated nitrogen cumulative concentration physical model to obtain the nitrogen cumulative concentration on the anode side of the stack.

[0023] Furthermore, the physical model of nitrogen cumulative concentration in step S23 adopts an artificial neural network, or a model using the following formula:

[0024]

[0025] Where, T′ is the stack temperature at the current moment, t 当前 The time is counted from the start of the fuel cell engine to the current time.

[0026] Furthermore, step S4 further includes:

[0027] S41. Regularly obtain the gas pressure P1 at the front inlet of the anode exhaust valve of the stack and the gas pressure P2 at the rear outlet;

[0028] S42. Input the gas pressures P1 and P2 into a pre-calibrated gas flow rate physical model to obtain the gas flow rate Q of the stack anode;

[0029] S43. Identify whether the gas flow rate Q is greater than the cumulative concentration of nitrogen on the anode side If so, close the anode exhaust valve and execute step S1; otherwise, maintain the open state of the anode exhaust valve unchanged and continue to identify steps S41 to S43 of the next cycle.

[0030] Furthermore, the physical model of the gas flow rate in step S42 adopts an artificial neural network, or a model using the following formula:

[0031]

[0032] Where d is the diameter of the exhaust valve, is the molecular mass of nitrogen.

[0033] Furthermore, before step S1, the method further includes the following steps:

[0034] S0. After recognizing that the system discreteness of the fuel cell engine is greater than a threshold, the anode exhaust valve is started to perform an exhaust operation.

[0035] Furthermore, step S0 further includes:

[0036] S01. Obtaining all single-chip voltages of the fuel cell;

[0037] S02. Identify whether any single cell voltage of the fuel cell is less than the voltage threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S03;

[0038] S03. Obtain the discreteness of the data set consisting of all single-chip voltages;

[0039] S04. Identify whether the discrete degree exceeds a threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S1.

[0040] Furthermore, a nitrogen concentration sensor is arranged on the inner wall of the pipe at the front inlet of the anode exhaust valve to directly collect the cumulative concentration of nitrogen on the anode side as supplementary data; and the method further includes the following steps:

[0041] S5. Identify that the nitrogen concentration sensor data exceeds the set concentration threshold, start the anode exhaust valve to perform the exhaust operation, and execute step S4.

[0042] Furthermore, a gas flow sensor is arranged on the inner wall of the pipe at the front inlet or the rear outlet of the anode exhaust valve to directly collect the gas flow rate of the stack anode as supplementary data; and the method further includes the following steps:

[0043] S6. Identify whether the gas flow sensor data is greater than the cumulative concentration of nitrogen on the anode side. If so, close the anode exhaust valve and execute step S1. Otherwise, maintain the state of the anode exhaust valve unchanged.

[0044] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0045] 1. A control algorithm that combines the diffusion coefficient with the performance of a single fuel cell chip is provided. The algorithm first reads the voltage information of the fuel cell chip. When the voltage is less than a preset voltage threshold, the anode exhaust valve is opened to exhaust the gas. Otherwise, the relationship between the fuel cell's discreteness and the preset discreteness threshold is determined. When the discreteness exceeds the preset voltage threshold, the anode exhaust valve is opened to exhaust the gas. Otherwise, no exhaust is performed. When the fuel cell chip performance and discreteness are both within a reasonable range, the diffusion coefficient is calculated and the exhaust strategy is implemented, achieving dynamic adjustment of the nitrogen diffusion rate over a time scale.

[0046] 2. The dynamic calculation of nitrogen concentration in the hydrogen chamber and the discharge flow of the anode exhaust valve during engine operation is realized.

[0047] 3. A startup strategy that integrates multiple judgment items such as nitrogen concentration, single-chip performance, system consistency, and exhaust flow has been implemented.

[0048] 4. An auxiliary judgment strategy is added through steps S0 and S5. When the nitrogen concentration on the anode side is too high, it will cause the performance of the fuel cell stack to decline. Therefore, when the engine performance decline is identified, the system opens the anode exhaust valve for exhaust operation. When it is identified that the system discreteness (standard deviation) is greater than the threshold, the anode exhaust valve is also opened for exhaust operation.

[0049] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the invention, nor is it intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0051] Figure 1 A schematic diagram showing the composition of the anode exhaust valve control method for a fuel cell engine according to Example 1 is shown;

[0052] Figure 2 A schematic diagram of a nitrogen diffusion model for a fuel cell engine according to Example 1 is shown;

[0053] Figure 3 A schematic diagram of the anode exhaust valve control logic of Example 2 is shown.

[0054] Reference numerals

[0055] 6 - cathode flow channel (air); 7 - first gas diffusion layer; 8 - membrane electrode; 9 - second gas diffusion layer; 10 - anode flow channel (hydrogen). DETAILED DESCRIPTION

[0056] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0057] As used herein, the term "including" and its variations represent open inclusion, i.e., "including but not limited to." Unless otherwise stated, the term "or" means "and / or." The term "based on" means "based at least in part on." The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0058] First, the abbreviations and their definitions involved in the present invention are introduced below.

[0059] Fuel cell engine: A device that converts chemical energy of hydrogen and oxygen into electrical energy through electrochemical reactions, including a fuel supply system, an oxidant supply system, a cooling system, a fuel stack, etc.

[0060] Anode exhaust valve: also known as hydrogen exhaust valve, its function is to periodically discharge nitrogen that penetrates from the cathode during the operation of the fuel cell engine to prevent the accumulation of nitrogen concentration from affecting engine performance.

[0061] Hydrogen injection: The function of the hydrogen injector is to provide the fuel cell stack with sufficient flow and sufficient concentration of hydrogen to ensure the normal reaction.

[0062] Hydrogen circulation component: includes an ejector or hydrogen pump, which recirculates the hydrogen at the outlet of the fuel cell stack back to the inlet of the fuel cell stack to avoid hydrogen waste, while ensuring the flow of hydrogen entering the stack and ensuring the normal progress of the reaction.

[0063] Example 1

[0064] One embodiment of the present invention discloses a method for controlling an anode exhaust valve of a fuel cell engine. Figure 1 As shown, the following steps are included:

[0065] S1. Get the ambient temperature T amb , total fuel cell operating time t 总, input into the pre-calibrated nitrogen diffusion model to obtain the nitrogen permeability coefficient of the proton exchange membrane in the fuel cell stack;

[0066] S2. Obtain the current flow rate, temperature, pressure, and humidity of the tail gas on the cathode and anode sides of the stack, respectively, and calculate the cumulative nitrogen concentration on the anode side of the stack based on the nitrogen permeability coefficient;

[0067] S3. Identify whether the cumulative concentration of nitrogen on the anode side exceeds the set concentration threshold. If so, open the anode exhaust valve and execute step S4. Otherwise, return to step S1.

[0068] S4. Obtain the gas pressures at the front and rear ends of the stack anode exhaust valve respectively, and then determine the gas flow rate of the stack anode, and identify whether the gas flow rate is greater than the accumulated nitrogen concentration on the anode side. If so, close the anode exhaust valve and execute step S1; otherwise, maintain the state of the anode exhaust valve unchanged.

[0069] When implementing, if Figure 2 As shown, hydrogen and air enter the fuel cell stack through the cathode flow channel 6 and the anode flow channel 10, respectively, and diffuse through the second gas diffusion layer 9 to the membrane electrode 8. Hydrogen separates into protons and electrons at the membrane electrode, and the protons combine with water to form hydronium ions. Nitrogen diffuses from the cathode flow channel 6 to the anode flow channel 10 under the concentration gradient, resulting in nitrogen accumulation on the anode side.

[0070] The controller reads the operating time of the fuel cell, obtains the relationship between the operating time and the diffusion coefficient, and then calculates the nitrogen permeability coefficient of the membrane. At the same time, it obtains relevant information such as temperature, humidity, flow rate, pressure on both sides of the cathode and anode. After correlating with the diffusion coefficient, it calculates the cumulative concentration of nitrogen on the anode side. When the cumulative concentration is greater than the preset nitrogen accumulation threshold of the fuel cell, the system opens the anode exhaust valve to exhaust. Otherwise, the calculation continues. In the process of opening the anode exhaust valve, the flow rate flowing through the anode exhaust valve is evaluated. If the discharged flow rate is greater than the accumulated concentration of nitrogen, the exhaust is stopped. Otherwise, the exhaust continues. After the above cycle is completed, it is repeated to enter the next cycle.

[0071] Compared to existing technologies, the fuel cell engine anode exhaust valve control method provided in this embodiment uses the nitrogen permeation coefficient of the proton exchange membrane to estimate the nitrogen permeation rate of the proton exchange membrane. This is used as the basis for the decision-making process of the anode exhaust valve opening, enabling precise control of the opening and closing of the anode exhaust valve of the fuel cell engine. Over time, the membrane permeation rate will shift, causing changes in the nitrogen permeation rate and accumulation rate. This strategy enables dynamic regulation over a longer timescale.

[0072] Example 2

[0073] Based on the improvement of Example 1, step S1 obtains the nitrogen permeability coefficient λ of the proton exchange membrane in the fuel cell stack by the nitrogen diffusion model in the following formula:

[0074]

[0075] in,

[0076]

[0077] The range of t is 0→t 总 , where κ is the coefficient of variation of the membrane electrode over time, is the nitrogen mole fraction on the anode side, t is the time, is the nitrogen constant, T is the normal operating temperature of the stack, P a is the hydrogen tail gas pressure on the anode side, S is the effective area of ​​the single cell of the stack, V is the cavity volume of the stack anode, P c is the air exhaust pressure on the cathode side, E N 2 is the enthalpy of nitrogen, ξ is the water content in the membrane, V d is the volume of the dry film, V w is the volume of the wet film.

[0078] Preferably, step S2 further comprises:

[0079] S21 obtains the current moment of the cathode side of the stack air exhaust flow, temperature, pressure and humidity;

[0080] S22 obtains the current moment of the anode side of the stack hydrogen exhaust flow, temperature, pressure and humidity;

[0081] S23. Input the above-mentioned cathode side air exhaust flow, temperature, pressure and humidity, anode side hydrogen exhaust flow, temperature, pressure and humidity, and nitrogen permeability coefficient into the pre-calibrated nitrogen cumulative concentration physical model to obtain the nitrogen cumulative concentration on the anode side of the stack.

[0082] Preferably, the physical model of nitrogen cumulative concentration in step S23 adopts an artificial neural network, or a model using the following formula:

[0083]

[0084] Where, T′ is the stack temperature at the current moment, t 当前 The time is counted from the start of the fuel cell engine to the current time.

[0085] Preferably, step S4 further comprises:

[0086] S41. Regularly obtain the gas pressure P1 at the front inlet of the anode exhaust valve of the stack and the gas pressure P2 at the rear outlet;

[0087] S42. Input the gas pressures P1 and P2 into a pre-calibrated gas flow physical model to obtain the gas flow rate Q of the stack anode. The flow capacity of the exhaust valve is affected by many factors, such as the diameter, the pressure difference between the front and rear ends of the exhaust, the exhaust rate, humidity, temperature, and other parameters. In general, the gas flow rate can be calculated using the following formula:

[0088]

[0089] Where d is the diameter of the exhaust valve, is the molecular mass of nitrogen;

[0090] Within a certain period of time, the flow rate flowing through the anode exhaust valve can be calculated in an integral form to obtain a curve showing the relationship between flow rate and time.

[0091] S43. Identify whether the gas flow rate Q is greater than the cumulative concentration of nitrogen on the anode side If so, close the anode exhaust valve and execute step S1; otherwise, maintain the open state of the anode exhaust valve unchanged and continue to identify steps S41 to S43 of the next cycle.

[0092] Preferably, the method further comprises the following steps before step S1:

[0093] S0. After recognizing that the system discreteness of the fuel cell engine is greater than a threshold, the anode exhaust valve is started to perform an exhaust operation.

[0094] Preferably, if Figure 3 As shown, step S0 further includes:

[0095] S01. Obtaining all single-chip voltages of the fuel cell;

[0096] S02. Identify whether any single cell voltage of the fuel cell is less than the voltage threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S03;

[0097] S03. Obtain the discreteness of the data set consisting of all single-chip voltages;

[0098] S04. Identify whether the discrete degree exceeds a threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S1.

[0099] Preferably, the method further comprises the steps of:

[0100] S7. After recognizing that the performance of the fuel cell engine has deteriorated, the anode exhaust valve is started to perform an exhaust operation.

[0101] Through the above-mentioned auxiliary judgment strategy added in steps S0 and S5, when the nitrogen concentration on the anode side is too high, it will cause the performance of the fuel cell stack to decline. Therefore, when the engine performance decline is recognized, the system opens the anode exhaust valve to perform exhaust operation. When the system discreteness (standard deviation) is recognized to be greater than the threshold, the anode exhaust valve is also opened to perform exhaust operation. For specific logic, see Figure 3 .

[0102] Preferably, a nitrogen concentration sensor is arranged on the inner wall of the pipe at the front inlet of the anode exhaust valve to directly collect the cumulative concentration of nitrogen on the anode side as supplementary data; and the method further comprises the following steps:

[0103] S5. Identify that the nitrogen concentration sensor data exceeds the set concentration threshold, start the anode exhaust valve to perform the exhaust operation, and execute step S4.

[0104] Preferably, a gas flow sensor is arranged on the inner wall of the pipe at the front inlet or the rear outlet of the anode exhaust valve to directly collect the gas flow rate of the stack anode as supplementary data; and the method further includes the following steps:

[0105] S6. Identify whether the gas flow sensor data is greater than the cumulative concentration of nitrogen on the anode side. If so, close the anode exhaust valve and execute step S1. Otherwise, maintain the state of the anode exhaust valve unchanged.

[0106] Compared with the prior art, the anode exhaust valve control method for a fuel cell engine provided in this embodiment has the following beneficial effects:

[0107] 1. A control algorithm that combines the diffusion coefficient with the performance of a single fuel cell chip is provided. The algorithm first reads the voltage information of the fuel cell chip. When the voltage is less than a preset voltage threshold, the anode exhaust valve is opened to exhaust the gas. Otherwise, the relationship between the fuel cell's discreteness and the preset discreteness threshold is determined. When the discreteness exceeds the preset voltage threshold, the anode exhaust valve is opened to exhaust the gas. Otherwise, no exhaust is performed. When the fuel cell chip performance and discreteness are both within a reasonable range, the diffusion coefficient is calculated and the exhaust strategy is implemented, achieving dynamic adjustment of the nitrogen diffusion rate over a time scale.

[0108] 2. The dynamic calculation of nitrogen concentration in the hydrogen chamber and the discharge flow of the anode exhaust valve during engine operation is realized.

[0109] 3. A startup strategy that integrates multiple judgment items such as nitrogen concentration, single-chip performance, system consistency, and exhaust flow has been implemented.

[0110] 4. An auxiliary judgment strategy is added through steps S0 and S5. When the nitrogen concentration on the anode side is too high, it will cause the performance of the fuel cell stack to decline. Therefore, when the engine performance decline is identified, the system opens the anode exhaust valve for exhaust operation. When it is identified that the system discreteness (standard deviation) is greater than the threshold, the anode exhaust valve is also opened for exhaust operation.

[0111] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements over the prior art, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling an anode exhaust valve of a fuel cell engine, characterized in that: include: S1. Get the ambient temperature T amb , total fuel cell operating time t 总 , input into the pre-calibrated nitrogen diffusion model to obtain the nitrogen permeability coefficient of the proton exchange membrane in the fuel cell stack; S2. Obtain the current flow rate, temperature, pressure, and humidity of the tail gas on the cathode and anode sides of the stack, respectively, and calculate the cumulative nitrogen concentration on the anode side of the stack based on the nitrogen permeability coefficient; S3. Identify whether the cumulative concentration of nitrogen on the anode side exceeds the set concentration threshold. If so, open the anode exhaust valve and execute step S4. Otherwise, return to step S1. S4. Obtain the gas pressures at the front and rear ends of the stack anode exhaust valve respectively, and then determine the gas flow rate of the stack anode, and identify whether the gas flow rate is greater than the accumulated nitrogen concentration on the anode side. If so, close the anode exhaust valve and execute step S1; otherwise, maintain the state of the anode exhaust valve unchanged.

2. The anode exhaust valve control method of a fuel cell engine according to claim 1, characterized in that: Step S1 obtains the nitrogen permeability coefficient λ of the proton exchange membrane in the stack using the nitrogen diffusion model in the following formula: in, The range of t is 0→t 总 Where κ is the coefficient of change of membrane electrode with time dimension, is the nitrogen mole fraction on the anode side, t is the time, is the nitrogen constant, T is the normal operating temperature of the stack, P a is the hydrogen tail gas pressure on the anode side, S is the effective area of ​​the single cell of the stack, V is the cavity volume of the stack anode, P c is the air exhaust pressure on the cathode side, E N 2 is the enthalpy of nitrogen, ξ is the water content in the membrane, V d is the volume of the dry film, V w is the volume of the wet film.

3. The anode exhaust valve control method of a fuel cell engine according to claim 2, characterized in that: Step S2 further comprises: S21 obtains the current moment of the cathode side of the stack air exhaust flow, temperature, pressure and humidity; S22 obtains the current moment of the anode side of the stack hydrogen exhaust flow, temperature, pressure and humidity; S23. Input the above-mentioned cathode side air exhaust flow, temperature, pressure and humidity, anode side hydrogen exhaust flow, temperature, pressure and humidity, and nitrogen permeability coefficient into the pre-calibrated nitrogen cumulative concentration physical model to obtain the nitrogen cumulative concentration on the anode side of the stack.

4. The anode exhaust valve control method of a fuel cell engine according to claim 3, characterized in that: The physical model of nitrogen cumulative concentration in step S23 adopts an artificial neural network, or a model using the following formula: Where, T′ is the stack temperature at the current moment, t 当前 The time is counted from the start of the fuel cell engine to the current time.

5. The anode exhaust valve control method of a fuel cell engine according to claim 4, characterized in that: Step S4 further comprises: S41. Regularly obtain the gas pressure P1 at the front inlet of the anode exhaust valve of the stack and the gas pressure P2 at the rear outlet; S42. Input the gas pressures P1 and P2 into a pre-calibrated gas flow rate physical model to obtain the gas flow rate Q of the stack anode; S43. Identify whether the gas flow rate Q is greater than the cumulative concentration of nitrogen on the anode side If so, close the anode exhaust valve and execute step S1; otherwise, maintain the open state of the anode exhaust valve unchanged and continue to identify steps S41 to S43 of the next cycle.

6. The anode exhaust valve control method of a fuel cell engine according to claim 5, characterized in that: The physical model of the gas flow rate in step S42 adopts an artificial neural network, or adopts a model with the following formula: Where d is the diameter of the exhaust valve, is the molecular mass of nitrogen.

7. The anode exhaust valve control method for a fuel cell engine according to any one of claims 1 to 6, characterized in that: Before step S1, the method further includes the following steps: S0. After recognizing that the system discreteness of the fuel cell engine is greater than a threshold, the anode exhaust valve is started to perform an exhaust operation.

8. The anode exhaust valve control method of a fuel cell engine according to claim 7, characterized in that: Step S0 further includes: S01. Obtaining all single-chip voltages of the fuel cell; S02. Identify whether any single cell voltage of the fuel cell is less than the voltage threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S03; S03. Obtain the discreteness of the data set consisting of all single-chip voltages; S04. Identify whether the discrete degree exceeds a threshold; if so, start the anode exhaust valve to perform the exhaust operation, and then execute step S01 again; otherwise, execute step S1.

9. The anode exhaust valve control method of a fuel cell engine according to any one of claims 1 to 6, characterized in that: A nitrogen concentration sensor is arranged on the inner wall of the pipe at the front inlet of the anode exhaust valve to directly collect the cumulative nitrogen concentration on the anode side as supplementary data; and the method further includes the following steps: S5. Identify that the nitrogen concentration sensor data exceeds the set concentration threshold, start the anode exhaust valve to perform the exhaust operation, and execute step S4.

10. The anode exhaust valve control method of a fuel cell engine according to any one of claims 1 to 6, characterized in that: A gas flow sensor is arranged on the inner wall of the pipe at the front inlet or rear outlet of the anode exhaust valve to directly collect the gas flow rate of the stack anode as supplementary data; and the method further includes the following steps: S6. Identify whether the gas flow sensor data is greater than the cumulative concentration of nitrogen on the anode side. If so, close the anode exhaust valve and execute step S1. Otherwise, maintain the state of the anode exhaust valve unchanged.

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