Calibration method and device for quickly matching tail exhaust pipeline of fuel cell vehicle

Abstract

The invention belongs to the field of fuel cells, and particularly relates to a calibration method and device for a fuel cell automobile rapid matching exhaust pipeline. According to the invention, on the premise of not adding a sensor, the tail exhaust pipelines at the rear ends of fuel cell systems of different vehicle types can be quickly matched on a whole vehicle debugging site. Discharge of tail exhaust industrial water of the hydrogen loop can be accurately calibrated only through an existing pressure sensor of the system, and the influence caused by design difference of tail exhaust pipelines is reduced.

Description

Technical Field

[0001] This invention belongs to the field of fuel cells, specifically relating to a method and apparatus for rapid matching and calibration of exhaust pipes in fuel cell vehicles. Background Technology

[0002] Drainage of the hydrogen circuit in a fuel cell is a core technical aspect for maintaining the system's high efficiency and stable operation. Its importance is mainly reflected in the following four key dimensions: First, maintaining electrochemical reaction efficiency (directly affecting power generation performance): Incomplete drainage can lead to flooding: liquid water blocks the pores of the gas diffusion layer (GDL), preventing reactant gases (H2 / O2) from reaching the catalyst layer, thus reducing the active reaction area. Second, preventing physical structural damage (related to system lifespan): Membrane electrode corrosion: Incomplete drainage leads to localized flooding causing undergassing, and reversed battery voltage leads to permanent damage caused by carbon carrier corrosion. Ice formation and bursting: Incomplete drainage after shutdown causes ice to expand at -25°C, resulting in micropore rupture. Flow channel blockage: Water droplets accumulate, forming liquid, causing a sudden increase in pressure loss, and uneven gas distribution leads to localized overheating. Third, ensuring hydrogen utilization rate (determining economic viability): Frequent opening of the fuel cell drain valve often results in hydrogen being released into the air, leading to low hydrogen utilization. Fourthly, system safety protection (to avoid catastrophic accidents): Due to the large pressure deviation at the tail end, in addition to discharging water, hydrogen gas will also be released into the air. The concentration in the air will increase, exceeding the explosion threshold and causing irreversible consequences. Due to the pressure deviation at the tail end, drainage is incomplete, and liquid water will also be carried into the hydrogen circulation pump, causing the pump body to be damaged by droplet impact.

[0003] To address the drainage issue in the hydrogen loop of fuel cells, existing technologies typically employ the following methods: First, using a liquid level sensor to discharge when a certain liquid level is reached. This method offers relatively accurate drainage, but the sensors are expensive, and adding more sensors increases the cost of the fuel cell system. Second, using EIS (Electrode Identification System) to test the stack impedance to determine if the membrane electrode assembly (MEA) has excessive water content. If it is too high, the discharge frequency is increased. This method often requires significant time for calibration, and the EIS feedback values ​​tend to deviate under different temperature conditions, leading to inaccuracies in the corrected exhaust cycle. Third, installing hydrogen concentration sensors in the exhaust to detect excessively rapid discharge and correct the exhaust frequency. This method increases the number of sensors, and under conditions of condensed water droplets and high humidity in the exhaust gas, these sensors are prone to drift or rapid aging and failure. Summary of the Invention

[0004] This invention overcomes the aforementioned shortcomings by providing a method and apparatus for rapidly calibrating exhaust pipes for fuel cell vehicles. Without adding sensors, this invention enables rapid matching of exhaust pipes for fuel cell systems of different vehicle models at the on-site vehicle commissioning site. Furthermore, this invention can accurately calibrate the emission of liquid water from the hydrogen circuit exhaust using only existing pressure sensors in the system, reducing the impact of differences in exhaust pipe design.

[0005] The technical solution of this invention is as follows.

[0006] A method for rapid matching and calibration of exhaust pipes in fuel cell vehicles includes one of the following methods.

[0007] Method 1:

[0008] (1) Conduct data testing in the laboratory. First, install a manual valve at the rear end of the system tailpipe. Install pressure sensors at the front and rear ends of the manual valve and calculate the pressure difference P_err. With the fuel cell shut down, the air compressor is given a fixed speed of 30,000~50,000 r / min (preferably 30,000 r / min, based on the feedback value of the air inlet pressure sensor not exceeding 150 kPa). The back pressure valve is given an opening of 30~70% (preferably 50%, based on the feedback value of the air inlet pressure sensor not exceeding 150 kPa). Adjust the manual valve to ensure that P_err equals 5 kPa. Obtain the air pressure inlet to the fuel cell stack and record this value P_purg_x.

[0009] (2) Divide the pressure difference P_err in the tailpipe into 5 kPa, 10 kPa, 15 kPa, etc., obtain the P_purg_5, P_purg_10, and P_purg_15 data from step (1), and start the fuel cell system for precise calibration to obtain 0.1 to 2.0 A / cm 2 Under current density operating conditions, the tail discharge cycle (with the same valve opening time, but different valve closing times) is T_purg5, T_purg10, and T_purg15. (The calibration process can be improved by observing whether the drainage is sufficient by installing transparent plastic material at the lower end of the steam-water separator and the front end of the valve, which makes the calibration more accurate.)

[0010] (3) When installing the fuel cell system on the vehicle for prototype vehicle debugging and matching, set the same air compressor speed and back pressure valve opening as in step (1) and obtain the air inlet pressure data P_purg_card;

[0011] (4) Based on the P_purg_card data obtained in step (3), make the following judgments:

[0012] 1) If P_purg_card ≤ P_purg_5, then the tail period is T_purg_5;

[0013] 2) If P_purg_5 ≤ P_purg_card ≤ P_purg_10, then the tail row period is T_purg_10;

[0014] 3) If P_purg_10 ≤ P_purg_card ≤ P_purg_15, then the tail row period is T_purg_15.

[0015] Method 2:

[0016] (1) Conduct data testing in the laboratory. First, install a manual valve on the rear end pipeline of the fuel cell system. Install pressure sensors before and after the manual valve and calculate the pressure difference P_err. When the fuel cell is shut down, the air compressor is given a fixed speed of 30,000~50,000 r / min (preferably 30,000 r / min, and the value fed back by the air inlet pressure sensor should not exceed 150 kPa). The back pressure valve is given an opening of 30%~70% (preferably 50%, and the value fed back by the air inlet pressure sensor should not exceed 150 kPa). Adjust the manual valve to ensure that P_err is equal to 4 kPa, 6 kPa, 8 kPa, 10 kPa, 12 kPa, 14 kPa, and 16 kPa, and record the air pressure inlet to the fuel cell stack as P_purg_4, P_purg_6, P_purg_8, P_purg_10, P_purg_12, P_purg_14, and P_purg_16.

[0017] (2) After setting the manual valve opening to 5 kPa according to step (1) when the pressure difference P_err in the tailpipe is 0.1 to 2.0 A / cm 2 Under current density conditions, the hydrogen infeed pressure was calibrated to obtain the optimal target hydrogen infeed pressure P_h2in (ensuring that the fuel cell system performance reaches the optimal state, and the difference between the hydrogen infeed pressure and the air outlet pressure is between 5-15 kPa).

[0018] (3) When the fuel cell system is installed on the vehicle for prototype vehicle debugging and matching, the same air compressor speed and back pressure valve opening are set as in step (1) to obtain the air inlet pressure data P_purg_card;

[0019] (4) Based on the P_purg_card data obtained in step (3), use the linear correspondence to obtain the tail pressure difference P_err_card (for example, P_purg_card = P_purg_4, then P_err_card = 4kPa). At this time, increase the target hydrogen inlet pressure P = P_h2in + (P_err_card - 4) so ​​that the hydrogen inlet pressure is consistent with the pressure difference relative to the pressure value of the tail pipeline. If P_h2in deviates from the result of the initial step (2), it is necessary to ensure that the difference between the hydrogen inlet pressure and the air outlet pressure is between 5-15kPa to prevent the pressure difference between the hydrogen and air circuits from being too large.

[0020] An apparatus for a rapid matching calibration method for exhaust pipes of a fuel cell vehicle includes a hydrogen cylinder, a vehicle exhaust pipe, and a fuel cell system. The hydrogen cylinder is connected to the fuel cell system, and the exhaust outlet of the fuel cell system is connected to the vehicle exhaust pipe. The fuel cell system includes a humidifier, a fuel cell stack, a vapor-water separator, a hydrogen pump, an intercooler, and an air compressor. The air compressor is connected to the intercooler, the intercooler is connected to the air inlet of the humidifier, and the air outlet of the humidifier is connected to the air inlet of the fuel cell stack. The fuel cell stack is sequentially connected to the humidifier and a manual valve. The hydrogen cylinder is connected to the hydrogen inlet of the fuel cell stack. The fuel cell stack is sequentially connected to the vapor-water separator, the hydrogen pump, and the hydrogen inlet of the fuel cell stack. The bottom outlet of the vapor-water separator is connected to the vehicle exhaust pipe.

[0021] Furthermore, a back pressure valve is installed on the pipe between the humidifier and the vehicle's exhaust pipe.

[0022] Furthermore, an exhaust valve is installed on the pipe between the gas-water separator and the vehicle's exhaust pipe.

[0023] Furthermore, pressure sensors are installed at both ends of the manual valve.

[0024] Furthermore, an air inlet pressure sensor is installed on the pipeline between the humidifier and the fuel cell stack.

[0025] Furthermore, a hydrogen inlet pressure sensor is installed on the pipeline between the hydrogen cylinder and the fuel cell stack.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] 1. The present invention has a simple structure and low manufacturing cost. It only requires a small amount of manpower to perform a one-time calibration in a short period of time. If the fuel cell system is mass-produced to achieve economies of scale, it can save a lot of costs associated with adding sensors and other components.

[0028] 2. This invention has higher accuracy and does not have the risk of sensor failure in the later stage of the above-mentioned scheme using hydrogen concentration sensor, and will not cause uncontrollable deviation of the tail discharge cycle over time.

[0029] 3. This invention achieves matching of the vehicle's exhaust resistance through multiple methods, ensuring the fuel cell system remains in optimal operating condition, preventing flooding and extending the system's lifespan. This method differs from traditional methods relying on EIS (Electronic Information System), as EIS testing equipment uses different methods for sending and receiving data. Replacing the EIS diagnostic tool would result in redundant and wasted system development costs. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the vehicle's fuel cell system.

[0031] Figure 2 The flowchart of the method in Example 2;

[0032] Figure 3 This is the flowchart of the method in Example 3.

[0033] Figure 1 The components are as follows: 1. Manual valve; 2. Pressure sensor; 3. Back pressure valve; 4. Humidifier; 5. Fuel cell stack; 6. Gas-water separator; 7. Hydrogen pump; 8. Tail exhaust valve; 9. Hydrogen inlet stack pressure sensor; 10. Air inlet stack pressure sensor; 11. Intercooler; 12. Air compressor; 13. Hydrogen cylinder. Detailed Implementation

[0034] The technical solutions described below, in conjunction with specific illustrations, are presented to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and similar extended embodiments made by those skilled in the art without inventive effort are all within the scope of protection of this invention.

[0035] Example 1

[0036] like Figure 1As shown, this embodiment provides a rapid matching and calibration device for the exhaust pipe of a fuel cell vehicle, including a hydrogen cylinder 13, a vehicle exhaust pipe, and a fuel cell system; wherein the hydrogen cylinder 13 is connected to the fuel cell system, and the exhaust outlet of the fuel cell system is connected to the vehicle exhaust pipe; the fuel cell system includes a humidifier 4, a fuel cell stack 5, a gas-water separator 6, a hydrogen pump 7, an exhaust valve 8, an intercooler 11, and an air compressor 12; the air compressor 12 is connected to the intercooler 11, the intercooler 11 is connected to the air inlet of the humidifier 4, and the air outlet of the humidifier 4 is connected to the air inlet of the fuel cell stack 5; the fuel cell stack 5 is sequentially connected to the humidifier 4 and a manual valve 1, and pressure sensors 2 are installed at the front and rear ends of the manual valve 1; the hydrogen cylinder 13 is connected to the hydrogen inlet of the fuel cell stack 5; the fuel cell stack 5 is sequentially connected to the gas-water separator 6, the hydrogen pump 7, and the hydrogen inlet of the fuel cell stack 5; the bottom outlet of the gas-water separator 6 is connected to the vehicle exhaust pipe. A back pressure valve 3 is installed on the pipe between the humidifier 4 and the vehicle exhaust pipe. An exhaust valve 8 is installed on the pipe between the gas-water separator 6 and the vehicle exhaust pipe. An air inlet pressure sensor 10 is installed on the pipe between the humidifier 4 and the fuel cell stack 5. A hydrogen inlet pressure sensor 9 is installed on the pipe between the hydrogen tank 13 and the fuel cell stack 5.

[0037] Example 2

[0038] This embodiment uses the device from Embodiment 1 to provide a method for rapid matching and calibration of the exhaust pipe of a fuel cell vehicle. Figure 2 As shown, the steps are as follows:

[0039] (1) Data testing was conducted in the laboratory. First, a manual valve was installed at the rear end of the system tailpipe. Pressure sensors were installed at the front and rear ends of the manual valve, and the pressure difference P_err was calculated. When the fuel cell was shut down, the air compressor was given a fixed speed of 30,000 r / min, the back pressure valve was given a 50% opening, and the manual valve was adjusted to ensure that P_err was equal to 5 kPa. The air pressure entering the stack was obtained and recorded as P_purg_x.

[0040] (2) The pressure difference P_err in the tailpipe is divided into 5kPa, 10kPa, 15kPa, etc. According to step (1), the data of P_purg_5, P_purg_10, P_purg_15 are obtained by testing, and the fuel cell system is turned on for precise calibration. The tailpipe emission cycle (tailpipe cycle of different current densities is a set of data) T_purg_5, T_purg_10, T_purg_15 under different current density conditions is obtained. In this embodiment, during the calibration process, transparent plastic material can be installed at the lower end of the gas-water separator and the front end of the valve to observe whether the drainage is sufficient, so that the calibration is more accurate.

[0041] (3) When the fuel cell system is installed on the vehicle for prototype testing and matching, the air compressor is given a fixed speed of 30,000 r / min and the back pressure valve is given a 50% opening to obtain the air inlet pressure data P_purg_card.

[0042] (4) Based on the P_purg_card data obtained in step (3), make the following judgments:

[0043] 1) If P_purg_card ≤ P_purg_5, then the tail period is T_purg_5;

[0044] 2) If P_purg_5 ≤ P_purg_card ≤ P_purg_10, then the tail row period is T_purg_10;

[0045] 3) If P_purg_10 ≤ P_purg_card ≤ P_purg_15, then the tail row period is T_purg_15.

[0046] Example 3

[0047] This embodiment uses the device from Embodiment 1 to provide a method for rapid matching and calibration of the exhaust pipe of a fuel cell vehicle. Figure 3 As shown, the steps are as follows:

[0048] (1) Data testing was conducted in the laboratory. First, a manual valve was installed on the rear end pipeline of the fuel cell system. Pressure sensors were installed before and after the manual valve and the pressure difference P_err was calculated. When the fuel cell was shut down, the air compressor was given a fixed speed of 30,000 r / min and the back pressure valve was given a 50% opening. The manual valve was adjusted to ensure that P_err was equal to 4 kPa, 6 kPa, 8 kPa, 10 kPa, 12 kPa, 14 kPa, and 16 kPa. The air pressure in the stack was recorded as P_purg_4, P_purg_6, P_purg_8, P_purg_10, P_purg_12, P_purg_14, and P_purg_16.

[0049] Test data summary table:

[0050] Serial Number P_err pressure / kPa Charged air pressure in the fuel cell stack / kPa 1 4 102 2 6 104 3 8 106 4 10 108 5 12 110 6 14 112 7 16 114

[0051] (2) After setting the hand valve opening to 5 kPa according to step (1) when the tailpipe pressure difference P_err is set, the hydrogen inlet pressure is calibrated under different current density conditions to obtain the optimal target hydrogen inlet pressure P_h2in (to ensure that the fuel cell system performance reaches the optimal state and the difference between the hydrogen inlet pressure and the air outlet pressure is between 5-15 kPa).

[0052] (3) When the fuel cell system is installed on the vehicle for prototype testing and matching, the air compressor is given a fixed speed of 30,000 r / min and the back pressure valve is given a 50% opening to obtain the air inlet pressure data P_purg_card;

[0053] (4) Based on the P_purg_card data obtained in step (3), use the linear correspondence to obtain the tail pressure difference P_err_card (for example, P_purg_card = P_purg_6, then P_err_card = 6kPa). At this time, increase the target hydrogen inlet pressure P = P_h2in + (P_err_card - 4) (for example, h2in is 125, P_purg_card = 6, then P = 125 + (6-4)) = 127 kPa, so that the hydrogen inlet pressure is consistent with the pressure difference of the tail pipeline. If P_h2in deviates from the result of the initial step (2), the inlet air pressure also needs to be increased to ensure that the difference between the hydrogen inlet pressure and the air outlet pressure is between 5-15kPa, to prevent the pressure difference between the hydrogen and air circuits from being too large.

[0054] It should be understood that the above detailed description of the technical solutions of the present invention with reference to optimized embodiments is illustrative and not restrictive. It should not be considered that the specific implementation of the present invention is limited to this. For those skilled in the art, any modifications to the technical solutions described in the embodiments or equivalent substitutions of some technical features without departing from the concept of the present invention should be considered as falling within the scope of patent protection defined by the claims submitted by the present invention.

Claims

1. A method for rapid matching and calibration of exhaust pipes in a fuel cell vehicle, characterized in that, Includes the following steps: (1) Data testing was conducted in the laboratory. First, a manual valve was installed at the rear end of the system tailpipe. Pressure sensors were installed at the front and rear ends of the manual valve, and the pressure difference P_err was calculated. When the fuel cell was shut down, the air compressor was given a fixed speed of 30,000~50,000 r / min, and the back pressure valve was given an opening of 30~70%. The manual valve was adjusted to ensure that P_err was equal to 5 kPa. The air pressure entering the stack was obtained and recorded as P_purg_x. (2) Divide the pressure difference P_err in the tailpipe into 5 kPa, 10 kPa, and 15 kPa, obtain the P_purg_5, P_purg_10, and P_purg_15 data from step (1), and start the fuel cell system for precise calibration, obtaining 0.1 to 2.0 A / cm 2 The tail emission cycles T_purg5, T_purg10, and T_purg15 under current density conditions; (3) When installing the fuel cell system on the vehicle for prototype vehicle debugging and matching, set the same air compressor speed and back pressure valve opening as in step (1) and obtain the air inlet pressure data P_purg_card; (4) Based on the P_purg_card data obtained in step (3), make the following judgments: 1) If P_purg_card ≤ P_purg_5, then the tail period is T_purg_5; 2) If P_purg_5 ≤ P_purg_card ≤ P_purg_10, then the tail row period is T_purg_10; 3) If P_purg_10 ≤ P_purg_card ≤ P_purg_15, then the tail row period is T_purg_15.

2. A method for rapid matching and calibration of exhaust pipes in a fuel cell vehicle, characterized in that, Includes the following steps: (1) Data testing was conducted in the laboratory. First, a manual valve was installed on the rear end pipeline of the fuel cell system. Pressure sensors were installed before and after the manual valve and the pressure difference P_err was calculated. When the fuel cell was shut down, the air compressor was given a fixed speed of 30,000~50,000 r / min, and the back pressure valve was given an opening of 30%~70%. The manual valve was adjusted to ensure that P_err was equal to 4 kPa, 6 kPa, 8 kPa, 10 kPa, 12 kPa, 14 kPa, and 16 kPa. The air pressure in the stack was recorded as P_purg_4, P_purg_6, P_purg_8, P_purg_10, P_purg_12, P_purg_14, and P_purg_16. (2) After setting the manual valve opening to 5 kPa according to step (1) when the pressure difference P_err in the tailpipe is 0.1 to 2.0 A / cm 2 Under current density conditions, the hydrogen infeed pressure was calibrated to obtain the optimal target hydrogen infeed pressure P_h2in; (3) When the fuel cell system is installed on the vehicle for prototype vehicle debugging and matching, the same air compressor speed and back pressure valve opening are set as in step (1) to obtain the air inlet pressure data P_purg_card; (4) Based on the P_purg_card data obtained in step (3), use the linear correspondence to obtain the tail pressure difference P_err_card. At this time, increase the target hydrogen inlet pressure P = P_h2in + (P_err_card - 4) to make the hydrogen inlet pressure and the pressure difference relative to the pressure value of the tail pipeline consistent. If P_h2in deviates from the result of the initial step (2), it is necessary to ensure that the difference between the hydrogen inlet pressure and the air outlet pressure is between 5-15 kPa to prevent the pressure difference between the hydrogen and air circuits from being too large.

3. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle as described in claim 1 or 2, characterized in that, The system includes a hydrogen cylinder (13), a vehicle exhaust pipe, and a fuel cell system. The hydrogen cylinder (13) is connected to the fuel cell system, and the exhaust outlet of the fuel cell system is connected to the vehicle exhaust pipe. The fuel cell system includes a humidifier (4), a fuel cell stack (5), a gas-water separator (6), a hydrogen pump (7), an intercooler (11), and an air compressor (12). The air compressor (12) is connected to the intercooler (11), the intercooler (11) is connected to the air inlet of the humidifier (4), and the air outlet of the humidifier (4) is connected to the air inlet of the fuel cell stack (5). The fuel cell stack (5) is sequentially connected to the humidifier (4) and a manual valve (1). The hydrogen cylinder (13) is connected to the hydrogen inlet of the fuel cell stack (5). The fuel cell stack (5) is sequentially connected to the gas-water separator (6), the hydrogen pump (7), and the hydrogen inlet of the fuel cell stack (5). The bottom outlet of the gas-water separator (6) is connected to the vehicle exhaust pipe.

4. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle according to claim 3, characterized in that, A back pressure valve (3) is installed on the pipe between the humidifier (4) and the exhaust pipe of the vehicle.

5. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle according to claim 3, characterized in that, A tailpipe valve (8) is installed on the pipeline between the steam-water separator (6) and the vehicle tailpipe.

6. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle according to claim 3, characterized in that, Pressure sensors (2) are installed at the front and rear ends of the manual valve (1).

7. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle according to claim 3, characterized in that, An air inlet pressure sensor (10) is installed on the pipeline between the humidifier (4) and the fuel cell stack (5).

8. The apparatus for a rapid matching and calibration method for exhaust pipes in a fuel cell vehicle according to claim 3, characterized in that, A hydrogen inlet pressure sensor (9) is installed on the pipeline between the hydrogen cylinder (13) and the fuel cell stack (5).

Images