Air system, bench test control method thereof and bench test system

Abstract

The invention belongs to the technical field of fuel cell engines. The air system comprises an air compressor, an intercooler, a humidifier, an electric pile outlet air stop valve, an electric pile inlet air stop valve, a humidifier bypass valve, a fuel cell air inlet bypass valve, a back pressure valve, an air flow meter, an intercooler rear pressure sensor, an electric pile inlet pressure sensor and an electric pile inlet temperature sensor. The stack outlet temperature sensor, the sensor assembly for the bench test, the mass spectrometer for the bench test, the air inlet pipeline and the air outlet pipeline are detachable parts, and the sensor assembly for the bench test and the mass spectrometer for the bench test are used for the bench test and are detached after the test is finished. According to the invention, the detachable sensor assembly and the mass spectrometer are additionally arranged in the air system, and interlocking optimization is carried out by combining a bench test control method and a performance calculation result, so that the accuracy of a bench test result is ensured, the battery pack is protected, the calibration method has very important significance in the calibration process of the fuel cell engine, and the cost is saved.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell engine technology, specifically relating to an air system and its bench test control method and bench test system. Background Technology

[0002] A fuel cell engine is a process that converts the chemical energy of fuel and oxidant into electrical energy through a chemical reaction. For fuel cells, any substance containing hydrogen atoms can be used as fuel, with hydrogen being the cleanest. The only byproduct of its conversion process is water, enabling zero emissions. In addition, fuel cell engines offer advantages such as high power generation efficiency, high specific energy, and low noise.

[0003] A fuel cell engine mainly consists of a fuel cell stack, an air system, a fuel processing system, and a thermal management system. The air system provides clean air to the stack with suitable flow rate, temperature, pressure, and humidity. The air system primarily includes core components such as an air compressor, intercooler, humidifier, air shut-off valve, and air bypass valve. The air compressor is responsible for pressurizing the air, ensuring that the airflow and pressure entering and leaving the stack are within a suitable range. After passing through the air compressor, the air temperature increases to over 100°C, exceeding the stack's operating temperature, requiring cooling by the intercooler. The humidifier exchanges heat and moisture with the air exiting the intercooler through the high-temperature, high-humidity exhaust gas from the stack's cathode, ensuring that the air entering the stack meets the stack's humidity requirements. The air shut-off valve seals the fuel cell from the surrounding air when the fuel cell engine is not running. Various air bypass valves regulate the hydrogen concentration in the exhaust gas, control the humidity within the stack, and control the pressure on the cathode side of the fuel cell stack during operation.

[0004] During the bench testing phase of the fuel cell engine's air system, various sensors, such as pressure sensors, temperature sensors, and exhaust hydrogen concentration sensors, need to be installed to detect the operating status of each component and ensure that all components operate within normal ranges. From the perspective of cost and control strategy optimization, fuel cell engines do not need to install too many sensors during the vehicle operation phase. Therefore, various sensors need to be installed during the bench testing phase. Once optimized calibration data is obtained, the bench sensors can be removed. Therefore, the installation of bench sensors is a key aspect of the fuel cell engine development process.

[0005] Patent document 1 (CN115441015B) discloses a fuel cell air system and a fuel cell system. As fuel cell systems mature in the automotive industry, problems exposed during operation are becoming increasingly apparent, such as excessively high humidity in exhaust gases, limiting the noise reduction performance of mufflers; and insufficient system integration, restricting improvements in volumetric and mass power outputs. These problems also exist in the development and application of high-power fuel cell systems, and are even more pronounced. Furthermore, the increase in fuel cell system power is often accompanied by increased demands on intercooler heat exchange and humidifier humidification, which to some extent results in large and bulky single-stage intercoolers and humidifiers, failing to meet the high integration requirements of system development. The purpose of this invention is to provide a fuel cell air system and a fuel cell system to solve one or more technical problems existing in the prior art, or at least provide a beneficial alternative or create favorable conditions. However, the patent does not describe how to verify the system on a test bench or the related sensor arrangement.

[0006] Patent Document 2 (CN113644295B) discloses a fuel cell air system. Hydrogen fuel cells operate by generating electricity through a chemical reaction between hydrogen and oxygen. During the reaction, a suitable air supply with appropriate pressure and humidity is required, along with the smooth emission of exhaust gases. Therefore, the rational arrangement and regulation of the fuel cell air system are crucial. However, in traditional fuel cell air systems, the ventilation volume cannot be effectively regulated, resulting in significant energy waste. Furthermore, moisture accumulation occurs at the bottom of the device, and most systems lack effective monitoring of the air inlet and outlet pressure, temperature, and humidity within the fuel cell. This patent includes some sensors, but it does not provide a detailed explanation of how this air system is implemented on a test bench.

[0007] Currently, the air system and its bench test control methods have the following problems: The current focus is mainly on the optimization of the air system of the vehicle fuel cell engine, while the importance of bench testing for the fuel cell engine air system is ignored. The number of sensors and the data collected are very important for the bench test of the fuel cell engine air system. By collecting pressure and temperature data at different locations, it is possible to determine whether the components themselves meet the requirements, which is of great significance for the calibration process of the fuel cell engine. Summary of the Invention

[0008] The purpose of this invention is to provide an air system for bench testing, a bench testing system, and a control method thereof. By interlocking and optimizing the control method and performance calculation results of the air system bench test of a fuel cell engine, the accuracy of the bench test development results is ensured, the problems existing in the control method of the air system bench test of a fuel cell engine are solved, the battery pack in the fuel cell is protected, and the hydrogen concentration in the exhaust, the humidity of the air entering the stack, the pressure on the cathode side of the stack, and the air flow rate entering the cathode side are precisely controlled.

[0009] The specific details of the plan are as follows:

[0010] An air system for bench testing includes an air compressor, an intercooler, a humidifier, an outlet air shut-off valve for the fuel cell stack, an inlet air shut-off valve for the fuel cell stack, a humidifier bypass valve, a fuel cell inlet bypass valve, a back pressure valve, an air flow meter, an intercooler post-pressure sensor, an inlet fuel cell stack pressure sensor, an inlet fuel cell stack temperature sensor, an outlet fuel cell stack temperature sensor, a sensor assembly for bench testing, a mass spectrometer for bench testing, inlet and outlet air lines. An air shut-off valve, a humidifier bypass valve, a fuel cell inlet bypass valve, a back pressure valve, an air flow meter, an intercooler post-pressure sensor, an inlet stack pressure sensor, an inlet stack temperature sensor, an outlet stack temperature sensor, a bench test sensor assembly, and a bench test mass spectrometer are respectively installed on the inlet and / or outlet pipes. The bench test sensor assembly and the bench test mass spectrometer are detachably connected to the corresponding inlet and / or outlet pipes for bench testing and are removed after the test.

[0011] Furthermore, both the air compressor and the air flow meter are installed on the intake pipe. The air flow meter is located upstream of the air compressor and is used to measure the intake air flow. The air compressor is used to pressurize the air and ensure that the air flow and pressure entering and leaving the fuel cell stack are within a suitable range.

[0012] In this invention, after passing through an air filter, the air enters an air flow meter to measure the intake air flow. Then, the air enters an air compressor, which is responsible for pressurizing the air to ensure that the air flow and pressure entering and leaving the fuel cell are within a suitable range.

[0013] Furthermore, the intercooler is installed on the intake pipe to cool the compressed air coming out of the air compressor; the sensor assembly for bench testing includes an intercooler front temperature sensor, an intercooler front pressure sensor, and an intercooler rear temperature sensor. The intercooler front temperature sensor and the intercooler front pressure sensor are respectively installed on the intake pipe upstream of the intercooler, and the intercooler rear temperature sensor and the intercooler rear pressure sensor are respectively installed on the intake pipe downstream of the intercooler. The intercooler front temperature sensor, intercooler front pressure sensor, intercooler rear temperature sensor, and intercooler rear pressure sensor are used to measure the pressure and temperature before and after the intercooler, respectively.

[0014] After passing through the air compressor, the air temperature increases to over 100°C, exceeding the fuel cell stack's operating temperature. Therefore, the compressed air needs to be cooled by an intercooler. After the intercooler, the air enters the humidifier, where it exchanges heat and moisture with the high-temperature, high-humidity exhaust gas from the fuel cell stack cathode outlet, ensuring that the air entering the fuel cell stack meets the stack's humidity requirements. Four sensors—a temperature sensor before the intercooler, a pressure sensor before the intercooler, a temperature sensor after the intercooler, and a pressure sensor after the intercooler—are used to determine whether the pressure and temperature before and after the intercooler meet the requirements. These results are checked against the intercooler's performance parameters and the fuel cell engine's performance calculations. After calibration and optimization, only the pressure sensor after the intercooler is retained on the vehicle.

[0015] Furthermore, the humidifier is connected to both the intake and exhaust pipes to regulate the humidity of the air exiting the intercooler to meet the fuel cell stack's humidity requirements for the incoming air. The sensor assembly for bench testing also includes a humidifier dry-in / dry-out differential pressure sensor, a humidifier wet-in / wet-out differential pressure sensor, and a humidity sensor. The humidifier dry-in / dry-out differential pressure sensor, the humidifier wet-in / wet-out differential pressure sensor, and the humidifier bypass valve are respectively located at corresponding positions on the exhaust pipe, while the humidity sensor is located on the intake pipe. The humidifier dry-in / dry-out differential pressure sensor, the humidifier wet-in / wet-out differential pressure sensor, and the humidity sensor are used to measure the dry-side differential pressure, wet-side differential pressure, and humidity of the air exiting the humidifier, respectively.

[0016] The proton exchange membrane (PEM) of a fuel cell stack requires a humid environment to properly transport hydrogen protons. When the stack itself doesn't produce enough water, excessively dry air entering the stack will quickly carry away a large amount of water, affecting stack performance. Therefore, a humidifier is needed to provide the stack with air of a certain humidity. However, when the stack produces excessive water, excessively high humidity entering the stack will reduce its water-carrying capacity, and excessive water accumulation may lead to flooding of the membrane electrode assembly (MEA), causing localized hot spots or even reverse polarity issues. Therefore, if the humidity of the air entering the stack is insufficient, the opening of the humidifier bypass valve is adjusted to regulate the mass flow rate of humidified air entering the humidifier from the cathode outlet, thereby altering the humidification amount of dry air entering the cathode inlet. This ensures that the humidity of the air entering the stack meets the requirements, guaranteeing the normal operation of the fuel cell engine. Monitoring whether the humidity meets the requirements requires a relative humidity sensor. The parameters obtained from the dry-in / dry-out differential pressure sensor, the wet-in / wet-out differential pressure sensor, and the humidity sensor are used to determine whether the dry-side differential pressure, wet-side differential pressure, and humidity of the air exiting the humidifier meet the requirements. The results must be checked against the performance parameters of the humidifier itself and against the performance calculations of the fuel cell engine. After the calibration data optimization is completed, the above three sensors do not need to be installed on the vehicle and are only used for bench testing. They are removed after the test.

[0017] Furthermore, the inlet air shut-off valve is located on the inlet pipe, and the outlet air shut-off valve is located on the outlet pipe. When the fuel cell engine is stopped, both the inlet and outlet air shut-off valves are closed. The sensor assembly for bench testing also includes a pressure sensor before the inlet air shut-off valve, a pressure sensor after the outlet air shut-off valve, and an outlet pressure sensor. The inlet air shut-off valve pressure sensor, the inlet pressure sensor, and the inlet temperature sensor are respectively located at corresponding positions on the inlet pipe, and the outlet air shut-off valve pressure sensor, the outlet temperature sensor, and the outlet pressure sensor are respectively located at corresponding positions on the outlet pipe. The inlet air shut-off valve pressure sensor, the inlet pressure sensor, the inlet temperature sensor, the outlet temperature sensor, the outlet air shut-off valve pressure sensor, and the outlet pressure sensor are respectively used to measure the pressures before and after the outlet and inlet air shut-off valves, as well as the air temperatures entering and exiting the fuel cell stack.

[0018] When the fuel cell engine starts, the inlet and outlet air shut-off valves are closed, while the fuel cell intake bypass valve is open. After anode purging is complete, the fuel cell intake bypass valve closes, and the inlet and outlet air shut-off valves open again. When the fuel cell engine stops running, both the inlet and outlet air shut-off valves are closed. This is because if air remains at the cathode after the fuel cell stops running, the oxygen will permeate through the proton exchange membrane and gradually enter the anode. This can lead to a high overpotential at the anode after the fuel cell engine resumes operation, degrading the catalyst carbon support in the proton exchange membrane, resulting in catalyst loss, decreased stack performance and durability, and reduced stack lifespan. To avoid this, the outlet and outlet air shut-off valves need to be closed to seal the cathode circuit and prevent air entry. Simultaneously, the residual oxygen at the cathode should be consumed before shutting down the fuel cell engine, creating an oxygen-free environment and placing the stack in a hydrogen-protected state.

[0019] The pressure sensors before the inlet and outlet air shut-off valves, the pressure sensor after the outlet air shut-off valve, the inlet pressure sensor, the inlet temperature sensor, the outlet temperature sensor, and the outlet pressure sensor are used to determine whether the pressures before and after the inlet and outlet shut-off valves and the inlet and outlet temperatures meet the requirements. The results must be checked against the performance parameters of the inlet and outlet air shut-off valves themselves, as well as against the fuel cell engine performance calculations and the performance of the fuel cell stack itself. After the calibration data optimization is completed, only the inlet pressure sensor, inlet temperature sensor, and outlet temperature sensor are retained on the vehicle.

[0020] Furthermore, the sensor assembly for bench testing also includes an exhaust hydrogen concentration sensor, which is installed on the outlet pipe to monitor the hydrogen concentration in the exhaust gas; and a fuel cell intake bypass valve is installed on the outlet pipe to introduce air discharged from the humidifier into the exhaust gas through the outlet pipe to dilute the hydrogen concentration in the exhaust gas.

[0021] The flammability limit (volume fraction) of hydrogen ranges from 4.0% to 75.6%. Within this range, hydrogen can burn in air and may even explode. According to automotive regulations, the concentration of combustible gases in exhaust emissions must be below 75% of the minimum flammability limit, meaning the hydrogen volume fraction must be below 3.0%. However, during the start-stop process of a fuel cell engine, a high concentration of hydrogen is often emitted. The airflow from the cathode during normal operation is insufficient to reduce the hydrogen concentration to 3.0%. Directly increasing the airflow to the cathode would reduce the durability of the fuel cell stack. Therefore, to improve the safety and durability of the fuel cell engine, additional air is needed during start-stop and idling to dilute the hydrogen concentration in the exhaust. If the hydrogen concentration in the exhaust exceeds the limit, the opening of the fuel cell intake bypass valve is adjusted to introduce air that has passed through the humidifier into the exhaust pipe to dilute the hydrogen concentration in the exhaust. This ensures that the hydrogen concentration in the exhaust does not exceed the limit, allowing the fuel cell engine to operate normally. Monitoring the hydrogen concentration in the exhaust requires a hydrogen concentration sensor. If the air compressor experiences surge, adjust the opening of the fuel cell intake bypass valve to prevent surge. The exhaust hydrogen concentration sensor does not need to be installed on the vehicle; it is only used for bench testing and will be removed after the test.

[0022] Furthermore, a back pressure valve is installed on the exhaust pipe to control the pressure on the cathode side of the fuel cell stack; the sensor assembly for bench testing also includes a tailpipe pressure sensor to measure the exhaust pressure.

[0023] The back pressure valve controls the pressure on the cathode side of the fuel cell stack. Increased pressure within a certain range will raise the average voltage of the stack. However, increased pressure on the cathode side increases the demands on the air compressor's performance and also increases power consumption, requiring a balance. If the air pressure entering the cathode is insufficient, the back pressure valve opening is adjusted to meet the requirements, allowing the fuel cell engine to operate normally. Monitoring the air pressure on the cathode side is done using an inlet pressure sensor. If the inlet mass flow rate of the air entering the cathode is insufficient, the air compressor speed is adjusted to meet the requirements, allowing the fuel cell engine to operate normally. The exhaust pressure sensor measures the exhaust pressure. This data is used to calibrate the back pressure valve opening. The exhaust pressure sensor is not mounted on the vehicle; it is only used for bench testing and is removed after the test.

[0024] Furthermore, a mass spectrometer for bench testing is installed on the gas outlet pipeline to measure the mass-to-charge ratio of charged particles to determine key information about the substance, serving as a basis for accumulating fundamental data.

[0025] The mass spectrometer used for bench testing does not need to be installed on the vehicle; it is only used for bench testing and will be removed after the test.

[0026] A bench test system includes the aforementioned air system and an electric fuel cell stack, wherein the air system is connected to the electric fuel cell stack via an air inlet pipe and an air outlet pipe.

[0027] A control method for bench testing of an air system, using the aforementioned bench testing system, includes the following steps:

[0028] S1: Determine if the fuel cell engine is running;

[0029] S2: If the fuel cell engine starts, the inlet and outlet air shut-off valves of the fuel cell stack are closed, the fuel cell inlet bypass valve is opened, and after the anode scavenging is completed, the fuel cell inlet bypass valve is closed, and the inlet and outlet air shut-off valves of the fuel cell stack are opened, so that clean air with appropriate flow rate, temperature, pressure and humidity enters the fuel cell stack to participate in the reaction.

[0030] Step S3: If the fuel cell engine is not started, the inlet air shut-off valve 6 and the outlet air shut-off valve 5 of the fuel cell stack are closed to minimize the number of times air enters the fuel cell stack 4 and improve the lifespan of the fuel cell stack 4.

[0031] If the fuel cell engine is not started in step S3, the inlet air shut-off valve and the outlet air shut-off valve of the fuel cell stack will be closed to minimize the number of times air enters the fuel cell stack and improve the lifespan of the fuel cell stack.

[0032] S3: If the fuel cell engine does not start, close the inlet and outlet air shut-off valves, re-inspect the fuel cell engine, and then return to step S1 to start the test again.

[0033] S4: Based on the parameters obtained from the intercooler front temperature sensor, intercooler front pressure sensor, intercooler rear temperature sensor, and intercooler rear pressure sensor, determine whether the pressure and temperature before and after the intercooler meet the requirements. The result is checked against the performance parameters of the intercooler itself and against the performance calculation of the fuel cell engine. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0034] S5: Based on the parameters obtained from the dry-in and dry-out pressure difference sensors, the wet-in and wet-out pressure difference sensors, and the humidity sensor, determine whether the dry-side pressure difference, wet-side pressure difference, and humidity of the air coming out of the humidifier meet the requirements. The result is checked against the performance parameters of the humidifier itself and against the performance calculation of the fuel cell engine. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0035] S6: Based on the parameters obtained from the pressure sensor before the inlet stack air shut-off valve, the inlet stack pressure sensor, the inlet stack temperature sensor, the outlet stack temperature sensor, the pressure sensor after the outlet stack air shut-off valve, and the outlet stack pressure sensor, determine whether the pressure before and after the outlet stack air shut-off valve and the inlet stack temperature meet the requirements. This result is checked against the performance parameters of the inlet stack air shut-off valve and the outlet stack air shut-off valve themselves, and also against the fuel cell engine performance calculation and the stack performance itself. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0036] S7: Determine whether the exhaust pressure meets the requirements based on the parameters obtained from the exhaust pressure sensor. Check the result against the fuel cell engine performance calculation. If the requirements are met, proceed to the next step; otherwise, skip to step S8.

[0037] S8: Simultaneously optimize the air intake flow rate of the air path, the hydrogen intake flow rate of the hydrogen supply path, and the cooling water pump speed parameters. Optimize the calibration data, and after optimization, return to the previous step to continue the test.

[0038] S9: The inlet air shut-off valve and the outlet air shut-off valve of the fuel cell stack are opened to determine whether the humidity of the air entering the fuel cell stack meets the requirements. If it does not meet the requirements, proceed to the next step; if it meets the requirements, jump to step S11.

[0039] S10: Adjust the opening of the humidifier bypass valve to adjust the mass flow rate of the humidified air entering the humidifier from the cathode outlet, thereby changing the amount of humidification of the dry air entering the cathode inlet, so that the humidity of the air entering the stack meets the requirements and the fuel cell engine runs normally. The target air humidity value entering the stack is obtained by querying the MAP through the target current. Based on the deviation between the humidity sensor and the target air humidity value of the stack, the PID controller is used to control the opening of the humidifier bypass valve in a closed loop to achieve the required requirements. Then, proceed to step S21.

[0040] S11: Keep the humidifier bypass valve open, then proceed to step S21;

[0041] S12: In parallel with step S9, the inlet and outlet air shut-off valves of the fuel cell stack are opened to determine whether the hydrogen concentration in the tail gas exceeds the limit or whether air compressor surge occurs. If the limit is exceeded or air compressor surge occurs, proceed to the next step; if the hydrogen concentration in the tail gas does not exceed the limit and air compressor surge does not occur, jump to step S14.

[0042] S13: If the hydrogen concentration in the exhaust exceeds the limit, adjust the opening of the fuel cell intake bypass valve to introduce air from the humidifier into the exhaust pipe to dilute the hydrogen concentration in the exhaust; ensure that the hydrogen concentration in the exhaust does not exceed the limit, and the fuel cell engine operates normally; if the air compressor experiences surge, adjust the opening of the fuel cell intake bypass valve to prevent surge; the amount of hydrogen dilution air in the fuel cell intake bypass valve is calculated based on the current exhaust concentration and the exhaust safety concentration limit; the amount of anti-surge bypass air in the fuel cell intake bypass valve is calculated based on the surge boundary air amount under the current operating conditions and the target inlet air amount of the fuel cell; finally, the bypass air amount of the fuel cell intake bypass valve is the maximum value of the exhaust dilution hydrogen air amount and the anti-surge bypass air amount; the opening of the fuel cell intake bypass valve is obtained by looking up the bypass air amount in an open-loop table, and the required requirements are met by adjustment, then proceed to step S21;

[0043] S14: Maintain the opening of the fuel cell intake bypass valve and proceed to step S21;

[0044] S15: Parallel to step S9, when the inlet air shut-off valve and the outlet air shut-off valve of the fuel cell stack are opened, determine whether the inlet air pressure entering the cathode meets the requirements. If the inlet air pressure entering the cathode does not meet the requirements, proceed to the next step; if the inlet air pressure entering the cathode meets the requirements, jump to step S17.

[0045] S16: Adjust the back pressure valve opening to ensure that the pressure on the cathode side of the fuel cell stack meets the requirements and the fuel cell engine operates normally. The target air pressure value entering the stack is obtained by querying the MAP through the target current. By using the deviation between the pressure value of the fuel cell stack pressure sensor and the target pressure value of the stack, the back pressure valve opening is controlled in a closed loop by a PID controller. The required requirements are met by adjusting the back pressure valve opening to achieve the desired results. Then, proceed to step S21.

[0046] S17: Maintain the back pressure valve opening and proceed to step S21;

[0047] S18: Parallel to step S9, when the inlet air shut-off valve and outlet air shut-off valve of the fuel cell stack are opened, determine whether the inlet air mass flow rate into the cathode meets the requirements. If the inlet air mass flow rate into the cathode does not meet the requirements, proceed to the next step; if the inlet air mass flow rate into the cathode meets the requirements, jump to step S20.

[0048] S19: Adjust the air compressor speed to ensure that the intake air mass flow rate on the cathode side of the fuel cell stack meets the requirements and the fuel cell engine operates normally. The target intake air mass flow rate entering the fuel cell stack is obtained by querying the MAP through the target current. The deviation between the flow rate value and the target intake air mass flow rate of the fuel cell stack is measured by the air flow meter. The air compressor speed is controlled in a closed loop using a PID controller. The required requirements are met by adjustment. Then, proceed to step S21.

[0049] S20: Maintain the air compressor speed and proceed to step S21;

[0050] S21: The test ends when all parallel steps S9, S12, S15 and S18 meet the requirements of the bench test.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] 1. The air system of this invention adds bench test sensor components and bench test mass spectrometers at different locations to collect data such as pressure, temperature, humidity, air flow, and hydrogen concentration in the exhaust in real time. It also performs interlock optimization by combining the air system bench test control method and performance calculation results to determine whether the components themselves meet the requirements. If they do not meet the requirements, the calibration parameters are re-optimized to ensure the accuracy of the bench test development results. This solves the problems existing in the bench test control method of the fuel cell engine air system, realizes the protection of the battery pack in the fuel cell, and is of great significance to the calibration process of the fuel cell engine.

[0053] 2. The sensor assembly and mass spectrometer used for bench testing in the air system of this invention are both detachable components and can be removed after the air system bench test is completed, thus saving costs. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the connection between the air system and the fuel cell stack of the present invention.

[0055] Figure 2 This is a flowchart of the air system bench test control method of the present invention.

[0056] 1. Air compressor; 2. Intercooler; 3. Humidifier; 4. Fuel cell stack; 5. Outlet air shut-off valve; 6. Inlet air shut-off valve; 7. Humidifier bypass valve; 8. Fuel cell inlet bypass valve; 9. Back pressure valve; 10. Air flow meter; 11. Intercooler inlet temperature sensor; 12. Intercooler inlet pressure sensor; 13. Intercooler outlet temperature sensor; 14. Intercooler outlet pressure sensor; 15. Humidifier dry-inlet / dry-outlet differential pressure sensor; 16. Humidifier 17. Humidity sensor; 18. Pressure sensor before the fuel cell stack air shut-off valve; 19. Pressure sensor after the fuel cell stack air shut-off valve; 20. Fuel cell stack pressure sensor; 21. Fuel cell stack temperature sensor; 22. Fuel cell stack temperature sensor; 23. Fuel cell stack pressure sensor; 24. Tail exhaust hydrogen concentration sensor; 25. Tail exhaust pressure sensor; 26. Mass spectrometer for bench testing; 27. Inlet pipeline; 28. Outlet pipeline. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0058] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0059] It should be noted that the terms "front", "rear", "inner", "outer", "left", "right", etc., used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] It is particularly important to note that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals. The following section will discuss this further. Figure 1 and Figure 2 The present invention will now be described in detail.

[0061] Example 1:

[0062] See Figure 1As shown, an air system for bench testing includes an air compressor 1, an intercooler 2, a humidifier 3, an outlet air shut-off valve 5, an inlet air shut-off valve 6, a humidifier bypass valve 7, a fuel cell inlet bypass valve 8, a back pressure valve 9, an air flow meter 10, an intercooler post-pressure sensor 14, an inlet fuel cell pressure sensor 20, an inlet fuel cell temperature sensor 21, an outlet fuel cell temperature sensor 22, a bench testing sensor assembly, a bench testing mass spectrometer 26, an inlet air line 27, and an outlet air line 28. The air compressor 1, intercooler 2, humidifier 3, outlet air shut-off valve 5, inlet air line 6, humidifier bypass valve 7, fuel cell inlet bypass valve 8, back pressure valve 9, air flow meter 10, intercooler post-pressure sensor 14, inlet fuel cell pressure sensor 20, inlet fuel cell temperature sensor 21, outlet fuel cell temperature sensor 22, bench testing sensor assembly, bench testing mass spectrometer 26, inlet air line 27, and outlet air line 28 are also described. The fuel cell stack air shut-off valve 6, humidifier bypass valve 7, fuel cell inlet bypass valve 8, back pressure valve 9, air flow meter 10, intercooler post-pressure sensor 14, fuel cell stack inlet pressure sensor 20, fuel cell stack inlet temperature sensor 21, fuel cell stack outlet temperature sensor 22, bench test sensor assembly and bench test mass spectrometer 26 are respectively installed on the inlet pipe 27 and / or outlet pipe 28. The bench test sensor assembly and bench test mass spectrometer 26 are detachably connected to the corresponding inlet pipe 27 and / or outlet pipe 28 for bench testing and are removed after the test.

[0063] Both the air compressor 1 and the air flow meter 10 are installed on the air intake pipe 27. The air flow meter 10 is located upstream of the air compressor 1 and is used to measure the intake air flow. The air compressor 1 is used to pressurize the air and ensure that the air flow and pressure entering and leaving the fuel cell stack 4 are within a suitable range.

[0064] Intercooler 2 is installed on intake pipe 27 and is used to cool the compressed air coming out of air compressor 1. The sensor assembly for bench testing includes an intercooler front temperature sensor 11, an intercooler front pressure sensor 12, and an intercooler rear temperature sensor 13. The intercooler front temperature sensor 11 and the intercooler front pressure sensor 12 are respectively installed on the intake pipe 27 upstream of intercooler 2, and the intercooler rear temperature sensor 13 and the intercooler rear pressure sensor 14 are respectively installed on the intake pipe 27 downstream of intercooler 2. The intercooler front temperature sensor 11, the intercooler front pressure sensor 12, the intercooler rear temperature sensor 13, and the intercooler rear pressure sensor 14 are used to measure the pressure and temperature before and after intercooler 2, respectively.

[0065] The humidifier 3 is connected to both the intake pipe 27 and the outlet pipe 28 to regulate the humidity of the air coming out of the intercooler 2 to meet the humidity requirements of the fuel cell stack 4 for the incoming air. The sensor assembly for bench testing also includes a humidifier dry-in / dry-out differential pressure sensor 15, a humidifier wet-in / wet-out differential pressure sensor 16, and a humidity sensor 17. The humidifier dry-in / dry-out differential pressure sensor 15, the humidifier wet-in / wet-out differential pressure sensor 16, and the humidifier bypass valve 7 are respectively located at corresponding positions on the outlet pipe 28. The humidity sensor 17 is located on the intake pipe 27. The humidifier dry-in / dry-out differential pressure sensor 15, the humidifier wet-in / wet-out differential pressure sensor 16, and the humidity sensor 17 are respectively used to measure the dry-side differential pressure, the wet-side differential pressure, and the humidity of the air coming out of the humidifier 3.

[0066] The fuel cell stack air shut-off valve 6 is located on the air inlet pipe 27, and the fuel cell stack air shut-off valve 5 is located on the air outlet pipe 28. When the fuel cell engine is stopped, both the fuel cell stack air shut-off valve 6 and the fuel cell stack air shut-off valve 5 are closed. The sensor assembly for bench testing also includes a pressure sensor 18 before the fuel cell stack air shut-off valve, a pressure sensor 19 after the fuel cell stack air shut-off valve, and a fuel cell stack pressure sensor 23. The pressure sensor 18 before the fuel cell stack air shut-off valve, the fuel cell stack pressure sensor 20, and the fuel cell stack temperature sensor 21 are respectively located on the air inlet pipe. At the corresponding positions of the outlet air shut-off valve, the pressure sensor 19, the outlet temperature sensor 22, and the outlet pressure sensor 23 are respectively installed at the corresponding positions of the outlet air pipe 28. The pressure sensor 18, the inlet pressure sensor 20, the inlet temperature sensor 21, the outlet temperature sensor 22, the outlet air shut-off valve, the pressure sensor 19, and the outlet pressure sensor 23 are respectively used to measure the pressure before and after the outlet air shut-off valve 5 and the inlet air shut-off valve 6, as well as the air temperature entering and exiting the fuel cell.

[0067] The sensor assembly for bench testing also includes an exhaust hydrogen concentration sensor 24, which is installed on the exhaust pipe 28 to monitor the hydrogen concentration in the exhaust gas; and a fuel cell intake bypass valve 8, which is installed on the exhaust pipe 28 to introduce air discharged from the humidifier 3 into the exhaust gas through the exhaust pipe 28 to dilute the hydrogen concentration in the exhaust gas.

[0068] The back pressure valve 9 is located on the exhaust pipe 28 and is used to control the pressure on the cathode side of the fuel cell stack 4. The sensor assembly for bench testing also includes a tail pressure sensor 25 for measuring the exhaust pressure.

[0069] The mass spectrometer 26 for bench testing is set on the gas outlet pipe 28 and is used to measure the mass-to-charge ratio of charged particles to determine key information about the substance, serving as a basis for accumulating basic data.

[0070] Example 2:

[0071] The present invention also provides a bench test system, including the aforementioned air system and a fuel cell stack 4, wherein the air system is connected to the fuel cell stack 4 via an air inlet pipe 27 and an air outlet pipe 28.

[0072] Example 3:

[0073] See Figure 2 As shown, the present invention also provides a control method for air system bench testing, using the aforementioned bench testing system, the steps of which include:

[0074] S1: Determine if the fuel cell engine is running;

[0075] S2: If the fuel cell engine starts, the inlet stack air shut-off valve 6 and the outlet stack air shut-off valve 5 are closed, and the fuel cell inlet bypass valve 8 is opened. After the anode scavenging is completed, the fuel cell inlet bypass valve 8 is closed, and the inlet stack air shut-off valve 6 and the outlet stack air shut-off valve 5 are opened.

[0076] S3: If the fuel cell engine does not start, close the inlet stack air shut-off valve 6 and the outlet stack air shut-off valve 5, re-inspect the fuel cell engine, and then return to step S1 to start the test again.

[0077] S4: Based on the parameters obtained by the intercooler front temperature sensor 11, intercooler front pressure sensor 12, intercooler rear temperature sensor 13 and intercooler rear pressure sensor 14, determine whether the pressure and temperature before and after the intercooler 2 meet the requirements. The result is checked against the performance parameters of the intercooler 2 itself and against the performance calculation of the fuel cell engine. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0078] S5: Based on the parameters obtained by the humidifier dry-in dry-out differential pressure sensor 15, the humidifier wet-in wet-out differential pressure sensor 16, and the humidity sensor 17, determine whether the dry-side differential pressure, wet-side differential pressure, and humidity of the air coming out of the humidifier 3 meet the requirements. The result is checked against the performance parameters of the humidifier 3 itself and against the performance calculation of the fuel cell engine. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0079] S6: Based on the parameters obtained from the pressure sensor 18 before the inlet stack air shut-off valve, the inlet stack pressure sensor 20, the inlet stack temperature sensor 21, the outlet stack temperature sensor 22, the pressure sensor 19 after the outlet stack air shut-off valve, and the outlet stack pressure sensor 23, determine whether the pressure before and after the outlet stack air shut-off valve 5 and the inlet stack air shut-off valve 6, as well as the inlet and outlet stack temperatures, meet the requirements. This result is checked against the performance parameters of the inlet stack air shut-off valve 6 and the outlet stack air shut-off valve 5 themselves, and also against the fuel cell engine performance calculation and the performance of the stack 4 itself. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0080] S7: Determine whether the exhaust pressure meets the requirements based on the parameters obtained by the exhaust pressure sensor 25. Check the result against the fuel cell engine performance calculation. If the requirements are met, proceed to the next step; otherwise, jump to step S8.

[0081] S8: Simultaneously optimize the air intake flow rate of the air path, the hydrogen intake flow rate of the hydrogen supply path, and the cooling water pump speed parameters. Optimize the calibration data, and after optimization, return to the previous step to continue the test.

[0082] S9: The inlet air shut-off valve 6 and the outlet air shut-off valve 5 of the fuel cell stack are opened. It is determined whether the humidity of the air entering the fuel cell stack 4 meets the requirements. If it does not meet the requirements, proceed to the next step; if it meets the requirements, jump to step S11.

[0083] S10: Adjust the opening of the humidifier bypass valve 7 to adjust the mass flow rate of the humidified air entering the humidifier 3 from the cathode outlet, thereby changing the amount of humidification of the dry air entering the cathode inlet, so that the humidity of the air entering the fuel cell stack 4 meets the requirements and the fuel cell engine operates normally. The target air humidity value entering the fuel cell stack 4 is obtained by querying the MAP through the target current. Based on the deviation between the humidity sensor 17 and the target air humidity value of the fuel cell stack 4, the PID controller is used to control the opening of the humidifier bypass valve 7 in a closed loop to achieve the required requirements.

[0084] S11: Keep the humidifier bypass valve 7 open, then proceed to step S21;

[0085] S12: In parallel with step S9, the inlet fuel cell air shut-off valve 6 and the outlet fuel cell air shut-off valve 5 are opened to determine whether the hydrogen concentration in the tail gas exceeds the limit or whether the air compressor 1 surges. If the limit is exceeded or the air compressor 1 surges, proceed to the next step; if the hydrogen concentration in the tail gas does not exceed the limit and the air compressor 1 does not surge, jump to step S14.

[0086] S13: If the hydrogen concentration in the exhaust exceeds the limit, adjust the opening of the fuel cell intake bypass valve 8 to introduce air from the humidifier 3 into the exhaust pipe to dilute the hydrogen concentration in the exhaust; ensure that the hydrogen concentration in the exhaust does not exceed the limit, and the fuel cell engine operates normally; if the air compressor 1 experiences surge, adjust the opening of the fuel cell intake bypass valve 8 to prevent surge; the amount of hydrogen dilution air in the exhaust of the fuel cell intake bypass valve 8 is calculated based on the current exhaust concentration and the exhaust safety concentration limit; the amount of anti-surge bypass air in the fuel cell intake bypass valve 8 is calculated based on the surge boundary air amount under the current operating conditions and the target inlet air amount of the fuel cell; finally, the bypass air amount of the fuel cell intake bypass valve 8 is the maximum value of the exhaust dilution hydrogen air amount and the anti-surge bypass air amount; the opening of the fuel cell intake bypass valve 8 is obtained by looking up the bypass air amount in an open-loop table, and the required requirements are met by adjustment, then proceed to step S21;

[0087] S14: Keep the fuel cell intake bypass valve 8 open, then proceed to step S21;

[0088] S15: Parallel to step S9, when the inlet air shut-off valve 6 and the outlet air shut-off valve 5 of the fuel cell stack are opened, determine whether the inlet air pressure entering the cathode meets the requirements. If the inlet air pressure entering the cathode does not meet the requirements, proceed to the next step; if the inlet air pressure entering the cathode meets the requirements, jump to step S17.

[0089] S16: Adjust the opening of the back pressure valve 9 so that the pressure on the cathode side of the fuel cell stack 4 meets the requirements and the fuel cell engine runs normally. The target air pressure value entering the fuel cell stack is obtained by querying the target current MAP. By measuring the deviation between the pressure value of the fuel cell stack pressure sensor 20 and the target pressure value of the fuel cell stack 4, the opening of the back pressure valve 9 is controlled by a PID controller in a closed loop. The required requirements are met by adjustment, and the process jumps to step S21.

[0090] S17: Maintain the back pressure valve 9 at its opening, then proceed to step S21;

[0091] S18: Parallel to step S9, when the inlet air shut-off valve 6 and the outlet air shut-off valve 5 of the fuel cell stack are opened, determine whether the inlet air mass flow rate into the cathode meets the requirements. If the inlet air mass flow rate into the cathode does not meet the requirements, proceed to the next step; if the inlet air mass flow rate into the cathode meets the requirements, jump to step S20.

[0092] S19: Adjust the speed of air compressor 1 so that the intake mass flow rate of the cathode side of fuel cell stack 4 meets the requirements and the fuel cell engine runs normally. The target intake mass flow rate of the fuel cell stack 4 is obtained by querying the MAP through the target current. The deviation between the flow rate value and the target intake mass flow rate of the fuel cell stack 4 is measured by the air flow meter 10. The speed of air compressor 1 is controlled by closed loop using a PID controller. The required requirements are met by adjustment. Jump to step S21.

[0093] S20: Maintain the air compressor 1 speed and proceed to step S21;

[0094] S21: The test ends when all parallel steps S9, S12, S15 and S18 meet the requirements of the bench test.

[0095] The above embodiments are provided only to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An air system characterized by, The air system is used for bench test, comprising an air compressor (1), a intercooler (2), a humidifier (3), an air stop valve (5) out of the fuel cell, an air stop valve (6) into the fuel cell, a humidifier bypass valve (7), a fuel cell air inlet bypass valve (8), a back pressure valve (9), an air flow meter (10), a pressure sensor (14) behind the intercooler, a pressure sensor (20) into the fuel cell, a temperature sensor (21) into the fuel cell, a temperature sensor (22) out of the fuel cell, a sensor assembly for bench test, a mass spectrometer (26) for bench test, an air inlet pipeline (27) and an air outlet pipeline (28), the air compressor (1), the intercooler (2), the humidifier (3), the air stop valve (5) out of the fuel cell, the air stop valve (6) into the fuel cell, the humidifier bypass valve (7), the fuel cell air inlet bypass valve (8), the back pressure valve (9), the air flow meter (10), the pressure sensor (14) behind the intercooler, the pressure sensor (20) into the fuel cell, the temperature sensor (21) into the fuel cell, the temperature sensor (22) out of the fuel cell, the sensor assembly for bench test and the mass spectrometer (26) for bench test are respectively arranged on the air inlet pipeline (27) and / or the air outlet pipeline (28), and the sensor assembly for bench test and the mass spectrometer (26) for bench test are respectively detachably connected to the corresponding air inlet pipeline (27) and / or air outlet pipeline (28) and are used for bench test and are removed after the test.

2. The air system of claim 1, wherein, The air compressor (1) and the air flow meter (10) are arranged on the air inlet pipeline (27), the air flow meter (10) is located upstream of the air compressor (1) and is used for measuring the air inlet flow; and the air compressor (1) is used for pressurizing the air and ensuring that the air flow and pressure into and out of the fuel cell (4) are in a proper range.

3. The air system of claim 1, wherein, The intercooler (2) is arranged on the air inlet pipeline (27) and is used for cooling the compressed air out of the air compressor (1); the sensor assembly for bench test comprises a temperature sensor (11) before the intercooler, a pressure sensor (12) before the intercooler and a temperature sensor (13) behind the intercooler, the temperature sensor (11) before the intercooler and the pressure sensor (12) before the intercooler are arranged on the air inlet pipeline (27) upstream of the intercooler (2), the temperature sensor (13) behind the intercooler and the pressure sensor (14) behind the intercooler are arranged on the air inlet pipeline (27) downstream of the intercooler (2), and the temperature sensor (11) before the intercooler, the pressure sensor (12) before the intercooler, the temperature sensor (13) behind the intercooler and the pressure sensor (14) behind the intercooler are respectively used for measuring the pressure and temperature before and behind the intercooler (2).

4. The air system of claim 1, wherein, The humidifier (3) is connected to the air inlet pipeline (27) and the air outlet pipeline (28) at the same time, and is used for adjusting the humidity of the air from the intercooler (2) to meet the humidity requirement of the air entering the stack (4); the sensor assembly for the bench test further comprises a humidifier dry-in dry-out pressure difference sensor (15), a humidifier wet-in wet-out pressure difference sensor (16) and a humidity sensor (17), the humidifier dry-in dry-out pressure difference sensor (15), the humidifier wet-in wet-out pressure difference sensor (16) and the humidifier bypass valve (7) are respectively arranged at the corresponding positions of the air outlet pipeline (28), and the humidity sensor (17) is arranged on the air inlet pipeline (27); the humidifier dry-in dry-out pressure difference sensor (15), the humidifier wet-in wet-out pressure difference sensor (16) and the humidity sensor (17) are respectively used for measuring the dry side pressure difference, the wet side pressure difference and the humidity of the air from the humidifier (3).

5. The air system of claim 1, wherein, The air inlet pipeline (27) is provided with an air inlet valve (6), and the air outlet pipeline (28) is provided with an air outlet valve (5); when the fuel cell engine stops running, the air inlet valve (6) and the air outlet valve (5) are both in a closed state; the sensor assembly for the bench test further comprises an air inlet valve front pressure sensor (18), an air outlet valve rear pressure sensor (19) and an air outlet pressure sensor (23); the air inlet valve front pressure sensor (18), the air inlet pressure sensor (20) and the air inlet temperature sensor (21) are respectively arranged at the corresponding positions of the air inlet pipeline (27); the air outlet valve rear pressure sensor (19), the air outlet temperature sensor (22) and the air outlet pressure sensor (23) are respectively arranged at the corresponding positions of the air outlet pipeline (28); the air inlet valve front pressure sensor (18), the air inlet pressure sensor (20), the air inlet temperature sensor (21), the air outlet temperature sensor (22), the air outlet valve rear pressure sensor (19) and the air outlet pressure sensor (23) are respectively used for measuring the front and rear pressures of the air inlet valve (6) and the air outlet valve (5) and the air temperature of the inlet and outlet of the stack.

6. The air system of claim 1, wherein, The sensor assembly for the bench test further comprises a tail hydrogen concentration sensor (24) arranged on the air outlet pipeline (28) for monitoring the hydrogen concentration in the exhaust gas; the fuel cell air inlet bypass valve (8) is arranged on the air outlet pipeline (28) for introducing the air discharged from the humidifier (3) into the exhaust gas through the air outlet pipeline (28) to dilute the hydrogen concentration in the exhaust gas.

7. The air system of claim 1, wherein, The back pressure valve (9) is arranged on the air outlet pipeline (28) for controlling the pressure on the cathode side of the stack (4); the sensor assembly for the bench test further comprises a tail exhaust pressure sensor (25) for measuring the exhaust end pressure.

8. The air system of claim 1, wherein, The bench test mass spectrometer (26) is arranged on the air outlet pipeline (28) for measuring the mass-to-charge ratio of charged particles to determine the key information of the substance, which is used as the accumulation of basic data.

9. A bench test system characterized by, The air system as claimed in any one of claims 1-8, further comprising a stack (4), wherein the air system is connected to the stack (4) through the air inlet pipeline (27) and the air outlet pipeline (28).

10. A control method of an air system bench test, characterized by, The rack test system of claim 9, the steps comprising: S1: judging whether the fuel cell engine is started; S2: if the fuel cell engine is started, the air inlet and outlet stop valves (6, 5) are closed, the fuel cell air inlet bypass valve (8) is opened, after the anode purge is completed, the fuel cell air inlet bypass valve (8) is closed, and the air inlet and outlet stop valves (6, 5) are opened; S3: if the fuel cell engine is not started, the air inlet and outlet stop valves (6, 5) are closed, the fuel cell engine is re-inspected, and then the test is restarted from step S1; S4: judging whether the pressure and temperature before and after the intercooler (2) meet the requirements according to the parameters obtained by the temperature sensor (11) before the intercooler, the pressure sensor (12) before the intercooler, the temperature sensor (13) after the intercooler, and the pressure sensor (14) after the intercooler, the result is checked with the performance parameters of the intercooler (2) itself and the fuel cell engine performance calculation, if the requirements are met, the next step is performed, and if the requirements are not met, the step S8 is jumped to; S5: judging whether the dry side pressure difference, the wet side pressure difference, and the air humidity out of the humidifier (3) meet the requirements according to the parameters obtained by the dry-in and dry-out pressure difference sensor (15) of the humidifier, the wet-in and wet-out pressure difference sensor (16) of the humidifier, and the humidity sensor (17), the result is checked with the performance parameters of the humidifier (3) itself and the fuel cell engine performance calculation, if the requirements are met, the next step is performed, and if the requirements are not met, the step S8 is jumped to; S6: judging whether the pressure before and after the air inlet and outlet stop valves (6, 5), and the temperature in and out of the stack meet the requirements according to the parameters obtained by the pressure sensor (18) before the air inlet stop valve, the pressure sensor (20) in the stack, the temperature sensor (21) in the stack, the temperature sensor (22) out of the stack, the pressure sensor (19) after the air outlet stop valve, and the pressure sensor (23) in the stack, the result is checked with the performance parameters of the air inlet and outlet stop valves (6, 5) themselves and the fuel cell engine performance calculation and the stack (4) itself, if the requirements are met, the next step is performed, and if the requirements are not met, the step S8 is jumped to; S7: judging whether the exhaust pressure meets the requirements according to the parameter obtained by the exhaust pressure sensor (25), the result is checked with the fuel cell engine performance calculation, if the requirements are met, the next step is performed, and if the requirements are not met, the step S8 is jumped to; S8: synchronously optimizing the air inlet flow, the hydrogen inlet flow, the cooling water pump speed parameters, optimizing the calibration data, and returning to the previous step to continue the test after optimization. S9: the inlet air stop valve (6) and the outlet air stop valve (5) are opened, and it is judged whether the air humidity entering the stack (4) meets the requirement, if not, the next step is performed; if yes, it is jumped to step S11; S10: the opening of the humidifier bypass valve (7) is adjusted, the mass flow of the wet air at the cathode outlet entering the humidifier (3) is adjusted, the humidification amount of the dry air at the cathode inlet is changed, the air humidity entering the stack (4) meets the requirement, the fuel cell engine operates normally, the target air humidity value entering the stack (4) is obtained through the target current query MAP, the opening of the humidifier bypass valve (7) is closed loop controlled by the humidity sensor (17) and the target air humidity value deviation of the stack (4) using the PID controller, the required requirement is reached through adjustment, and it is jumped to step S21; S11: the opening of the humidifier bypass valve (7) is kept, and it is jumped to step S21; S12: in parallel with step S9, the inlet air stop valve (6) and the outlet air stop valve (5) are opened, it is judged whether the tail exhaust hydrogen concentration exceeds the limit value or whether the air compressor (1) surges, if the limit value is exceeded or the air compressor (1) surges, the next step is performed; if the tail exhaust hydrogen concentration does not exceed the limit value and the air compressor (1) does not surge, it is jumped to step S14; S13: if the tail exhaust hydrogen concentration exceeds the limit value, the opening of the fuel cell inlet bypass valve (8) is adjusted, the air passing through the humidifier (3) is introduced into the exhaust pipe to dilute the hydrogen concentration in the exhaust; the tail exhaust hydrogen concentration does not exceed the limit value, the fuel cell engine operates normally; if the air compressor (1) surges, the opening of the fuel cell inlet bypass valve (8) is adjusted to prevent the occurrence of surging; the tail exhaust dilution exhaust hydrogen air amount of the fuel cell inlet bypass valve (8) is calculated according to the current tail exhaust concentration and the tail exhaust safety concentration limit value; the anti-surge bypass air amount of the fuel cell inlet bypass valve (8) is calculated according to the surge boundary air amount under the current working condition and the fuel cell target inlet stack air amount; the final bypass air amount of the fuel cell inlet bypass valve (8) is the maximum value of the tail exhaust dilution exhaust hydrogen air amount and the anti-surge bypass air amount; the opening of the fuel cell inlet bypass valve (8) is obtained by open loop table lookup according to the bypass air amount, the required requirement is reached through adjustment, and it is jumped to step S21; S14: the opening of the fuel cell inlet bypass valve (8) is kept, and it is jumped to step S21; S15: in parallel with step S9, when the inlet air stop valve (6) and the outlet air stop valve (5) are opened, it is judged whether the inlet air pressure entering the cathode meets the requirement, if not, the next step is performed; if yes, it is jumped to step S17; S16: Adjusting the opening of the back pressure valve (9) to make the pressure of the cathode side of the stack (4) meet the requirement, and the fuel cell engine runs normally. The target air pressure value of the entering stack is obtained by the target current query MAP. The opening of the back pressure valve (9) is closed-loop controlled by the PID controller through the deviation of the pressure value of the entering stack pressure sensor (20) and the target pressure value of the stack (4), and the required value is reached by adjusting, and jumping to step S21; S17: Keeping the opening of the back pressure valve (9), and jumping to step S21; S18: In parallel with step S9, when the entering stack air stop valve (6) and the exiting stack air stop valve (5) are opened, it is judged whether the inlet air mass flow entering the cathode meets the requirement. If the inlet air mass flow entering the cathode does not meet the requirement, the next step is performed; if the inlet air mass flow entering the cathode meets the requirement, it is jumped to step S20; S19: Adjusting the speed of the air compressor (1) to make the inlet air mass flow of the cathode side of the stack (4) meet the requirement, and the fuel cell engine runs normally. The target inlet air mass flow of the stack (4) is obtained by the target current query MAP. The speed of the air compressor (1) is closed-loop controlled by the PID controller through the deviation of the flow value measured by the air flow meter (10) and the target inlet air mass flow of the stack (4), and the required value is reached by adjusting, and jumping to step S21; S20: Keeping the speed of the air compressor (1), and jumping to step S21; S21: When the parallel steps S9, S12, S15 and S18 all meet the requirements of the bench test, the test is ended.

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