An exhaust valve fault identification method based on a proportional valve duty cycle and a system applying the method

Abstract

The application discloses a kind of exhaust valve fault identification method based on proportional valve duty ratio and the system using the method.The method includes the following steps: fuel cell engine starts, reads current data, determines working condition point, calculates the proportional valve duty ratio data of exhaust valve opening and closing, forms two groups of fitting curves, compares two curves to determine whether there is overlap or intersection, and takes corresponding processing measures according to the comparison result.The system includes the application of the above system.The application can monitor whether the exhaust valve fails in real time without adding new sensors, limit the output power of fuel cell engine within the safety threshold and issue an alarm warning after diagnosing the failure, has lower investment cost, can ensure real-time monitoring of the exhaust valve, reduce the performance damage to the fuel cell, and improve the service life and safety.

Description

Technical Field

[0001] This invention relates to the technical field of fuel cell engines, and in particular to a method for identifying exhaust valve faults based on the proportional valve duty cycle and a system applying this method. Background Technology

[0002] A fuel cell is a device that directly converts chemical energy into electrical energy, generating electricity through the reaction of hydrogen and oxygen in the air. It is a clean and efficient energy conversion technology with the potential to replace traditional combustion power generation and traditional gasoline-powered vehicles. The hydrogen side of a fuel cell contains pure hydrogen, while the air side contains not only oxygen but also other gases such as nitrogen. These other gases diffuse from the air side to the hydrogen side due to the concentration difference. After prolonged diffusion, this leads to a decrease in the hydrogen concentration, affecting the fuel cell's engine performance and potentially causing electrochemical corrosion of the membrane electrode assembly (MEA). Currently, the solution to this problem is generally to install an exhaust valve to remove other gases from the hydrogen side. However, if the exhaust valve malfunctions and cannot be monitored and diagnosed in a timely manner, it can damage the fuel cell engine, affecting the normal operation of the fuel cell and even posing safety hazards. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for identifying exhaust valve faults based on the duty cycle of a proportional valve and a system that applies this method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a method for identifying exhaust valve faults based on the duty cycle of a proportional valve, the specific steps of which include:

[0005] S1, the fuel cell engine is turned on, and the fuel cell is in standby or running state;

[0006] S2, Read the current data to determine the operating point of the fuel cell;

[0007] S3, Under a given operating point, determine the duty cycle data of the exhaust valve opening and the proportional valve duty cycle data of the exhaust valve closing according to the exhaust valve cycle, and form two sets of fitting curves based on the data;

[0008] S4. Compare the two sets of fitted curves. If it is determined that the two sets of fitted curves overlap or intersect, it is determined that the exhaust valve has malfunctioned, the output power of the fuel cell engine is limited to within the safe threshold, and an exhaust valve malfunction alarm is issued.

[0009] 2. The exhaust valve fault identification method based on proportional valve duty cycle according to claim 1, characterized in that: in S3, the total running time and proportional valve duty cycle data of the exhaust valve opening are extracted in real time, and the proportional valve duty cycle data when the exhaust valve is open is recorded in real time to form the first fitting data.

[0010] As a further description of the above technical solution, in S3, the total running time and the proportional valve duty cycle data when the exhaust valve is closed are extracted in real time, and the proportional valve duty cycle data when the exhaust valve is closed is recorded in real time to form the second fitting data.

[0011] As a further description of the above technical solution, in S4, a first fitting curve and a second fitting curve are formed respectively using the first fitting data and the second fitting data;

[0012] If the first and second fitted curves do not intersect or overlap, it is determined that the exhaust valve is in normal condition and the fuel cell engine is operating under normal conditions.

[0013] As a further description of the above technical solution, the first fitting data and the first fitting curve correspond to the duty cycle data of the main proportional valve.

[0014] The second fitted data and the second fitted curve correspond to the duty cycle data of the Bypass proportional valve.

[0015] A system for identifying exhaust valve faults based on proportional valve duty cycle, comprising an electric stack;

[0016] The hydrogen recirculation device is used to supply hydrogen to the fuel cell stack;

[0017] The main proportional valve is connected to the hydrogen circulation device and is used to control the hydrogen supply of the hydrogen circulation device;

[0018] The Bypass proportional valve is connected to the fuel cell stack and is used to supply gas to the fuel cell stack.

[0019] The water distribution component is connected to the fuel cell stack and is used to remove excess gas and liquid, and maintain stable pressure inside the fuel cell stack.

[0020] Both the drain valve and the air vent valve are connected to the water distribution component;

[0021] The control system determines the duty cycle data of the exhaust valve opening and the proportional valve duty cycle data of the exhaust valve closing based on the exhaust valve cycle. It forms two sets of fitting curves based on the data and compares whether the two sets of fitting curves intersect or overlap. If they intersect or overlap, it is determined that the exhaust valve has malfunctioned.

[0022] As a further description of the above technical solution, the water separator is connected to the hydrogen circulation device, and the water separator will transport the discharged hydrogen back to the fuel cell stack through the hydrogen circulation device.

[0023] As a further description of the above technical solution, the hydrogen circulation device is either a hydrogen ejector or a hydrogen circulation pump.

[0024] As a further description of the above technical solution, the duty cycle of the main proportional valve and the cycle of the exhaust valve are read at low operating conditions.

[0025] Under high operating conditions, read the duty cycle of the Bypass proportional valve and the cycle of the exhaust valve.

[0026] As a further description of the above technical solution, the low operating point refers to the operating condition of the engine under low current.

[0027] The high operating point refers to the operating condition of the engine under high current.

[0028] The present invention has the following beneficial effects:

[0029] 1. This invention does not require the addition of new sensors. It can monitor whether the exhaust valve is malfunctioning by processing and analyzing the operating data during the operation of the fuel cell engine. After diagnosing the malfunction, it can limit the output power of the fuel cell engine within a safe threshold and issue an alarm warning. The cost is lower, while ensuring real-time monitoring of the exhaust valve, reducing damage to the fuel cell performance, and improving service life and safety. Attached Figure Description

[0030] Figure 1 This is a flowchart of the exhaust valve fault identification method proposed in this invention;

[0031] Figure 2 This is a schematic diagram of the operating conditions proposed in this invention;

[0032] Figure 3 This is a schematic diagram of the duty cycle curve of the exhaust valve at high and low operating conditions after processing, as proposed in this invention.

[0033] Figure 4 This is a schematic diagram of a system applying the method proposed in this invention.

[0034] Legend:

[0035] 1. Fuel cell stack; 2. Hydrogen circulation device; 3. Main proportional valve; 4. Bypass proportional valve; 5. Water distribution unit; 6. Drain valve; 7. Exhaust valve; 8. Control system. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Reference Figure 1-3 The present invention provides an embodiment of an exhaust valve fault identification method based on the duty cycle of a proportional valve: the specific steps of the method include:

[0038] S1, the fuel cell engine is turned on. The fuel cell is in standby or running state, which puts the fuel cell engine in the on state, so that the operating status of the fuel cell engine under high and low operating conditions can be monitored.

[0039] S2 reads current data from the current sensor in the DC-DC converter via the controller. The operating point is determined based on this current data. Specifically, when the collected current data is low, the fuel cell engine is at a low operating point. When the collected current data is high, the fuel cell engine is at a high operating point. For example, the current range of the fuel cell across all operating points is 50-500A, the low operating point corresponds to a current range of 50-200A, and the high operating point corresponds to a current range of 200-500A. See reference for details. Figure 2

[0040] S3. After determining the operating point, determine the duty cycle data of the proportional valve when the exhaust valve is open and the duty cycle data of the proportional valve when the exhaust valve is closed, respectively, based on the exhaust valve cycle. Two sets of fitting curves can be formed based on the collected data.

[0041] Specifically, at low operating conditions, the duty cycle data of the main proportional valve and the exhaust valve cycle are read; at high operating conditions, the duty cycle data of the bypass proportional valve and the exhaust valve cycle are read. Then, based on the exhaust valve's exhaust cycle, the total running time and the proportional valve duty cycle data when the exhaust valve is open are extracted in real time. A proportional valve duty cycle curve for when the exhaust valve is open is fitted based on the running time; this can be done using a function built into Excel. Simultaneously, based on the exhaust valve's exhaust cycle, the total running time and the proportional valve duty cycle data for when the exhaust valve is closed are extracted in real time. Similarly, the proportional valve duty cycle curve for when the exhaust valve is closed is fitted based on the running time. For details, please refer to [reference needed]. Figure 3 .

[0042] S4, please refer to Figure 3By comparing the two sets of fitted curves, it is determined whether there is overlap or intersection. Based on the comparison results, the state of the exhaust valve can be understood, and corresponding measures can be taken. Specifically, if the first fitted curve intersects or overlaps with the second fitted curve, the exhaust valve is found to be faulty, and the output power of the fuel cell engine is limited to within the safety threshold. The first fitted curve is obtained by processing the first fitted data, and the second fitted curve is obtained by processing the second fitted data. The first fitted data is the proportional valve duty cycle data when the exhaust valve is open, and the second fitted data is the proportional valve duty cycle data when the exhaust valve is closed.

[0043] If the first and second fitted curves do not intersect or overlap, the surface exhaust valve is in normal condition and the fuel cell engine is in normal operation.

[0044] Using the above method, without adding new sensors, the exhaust valve can be monitored for malfunctions during the operation of the fuel cell engine by processing and analyzing the operating data. After diagnosing the malfunction, the output power of the fuel cell engine can be limited within a safe threshold and an alarm warning can be issued. This method requires less investment and can ensure real-time monitoring of the exhaust valve, reducing damage to the fuel cell's performance, improving its service life and safety.

[0045] refer to Figure 4 This application provides an embodiment of a system for an exhaust valve fault identification method based on the proportional valve duty cycle, comprising an electric stack;

[0046] The hydrogen circulation device is connected to the fuel cell stack and is used to supply hydrogen to the fuel cell stack. The hydrogen circulation device can be a hydrogen ejector, a hydrogen circulation pump, or other types of hydrogen circulation devices, and can be adjusted according to actual needs.

[0047] The main proportional valve is connected to the hydrogen circulation device and is used to control the hydrogen supply of the hydrogen circulation device;

[0048] The Bypass proportional valve is connected to the fuel cell stack and is used to supply gas to the fuel cell stack.

[0049] The water distribution component is connected to the fuel cell stack and is used to remove excess gas and liquid, and maintain stable pressure inside the fuel cell stack.

[0050] Both the drain valve and the air vent valve are connected to the water distribution component;

[0051] The control system determines the duty cycle data of the exhaust valve opening and the proportional valve duty cycle data of the exhaust valve closing based on the exhaust valve cycle. It forms two sets of fitting curves based on the data and compares whether the two sets of fitting curves intersect or overlap. If they intersect or overlap, it is determined that the exhaust valve has malfunctioned.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An exhaust valve failure recognition method based on a proportional valve duty ratio, characterized by, The specific steps include: S1, the fuel cell engine is turned on, and the fuel cell is in standby or running state; S2, Read the current data to determine the operating point of the fuel cell; S3, Under a given operating point, determine the duty cycle data of the proportional valve when the exhaust valve is open and the duty cycle data of the proportional valve when the exhaust valve is closed, respectively, and form two sets of fitting curves based on the data; S4. Compare the two sets of fitted curves. If it is determined that the two sets of fitted curves overlap or intersect, it is determined that the exhaust valve has malfunctioned, the output power of the fuel cell engine is limited to within the safe threshold, and an exhaust valve malfunction alarm is issued. Specifically, at low operating conditions, the duty cycle data of the main proportional valve and the exhaust valve cycle are read; at high operating conditions, the duty cycle data of the bypass proportional valve and the exhaust valve cycle are read.

2. The exhaust valve fault identification method based on the proportional valve duty cycle according to claim 1, characterized in that: In S3, the total running time and the proportional valve duty cycle data when the exhaust valve is open are extracted in real time, and the proportional valve duty cycle data when the exhaust valve is open are recorded in real time to form the first fitting data.

3. The exhaust valve fault identification method based on the proportional valve duty cycle according to claim 2, characterized in that: In S3, the total running time and the proportional valve duty cycle data when the exhaust valve is closed are extracted in real time, and the proportional valve duty cycle data when the exhaust valve is closed are recorded in real time to form the second fitting data; In S4, the first fitting curve and the second fitting curve are formed by using the first fitting data and the second fitting data, respectively; If the first and second fitted curves do not intersect or overlap, it is determined that the exhaust valve is in normal condition and the fuel cell engine is operating under normal conditions.

4. A system for identifying exhaust valve faults based on the duty cycle of a proportional valve, characterized in that: Including fuel cell stacks; The hydrogen recirculation device is used to supply hydrogen to the fuel cell stack; The main proportional valve is connected to the hydrogen circulation device and is used to control the hydrogen supply of the hydrogen circulation device; The Bypass proportional valve is connected to the fuel cell stack and is used to supply gas to the fuel cell stack. The water distribution component is connected to the fuel cell stack and is used to remove excess gas and liquid, and maintain stable pressure inside the fuel cell stack. Both the drain valve and the air vent valve are connected to the water distribution component; The control system determines the duty cycle data of the exhaust valve opening and the proportional valve duty cycle data of the exhaust valve closing based on the exhaust valve cycle. It forms two sets of fitting curves based on the data and compares whether the two sets of fitting curves intersect or overlap. If they intersect or overlap, it is determined that the exhaust valve has malfunctioned. Among them, the duty cycle of the main proportional valve and the cycle of the exhaust valve are read at low operating conditions; Under high operating conditions, read the duty cycle of the Bypass proportional valve and the cycle of the exhaust valve.

5. The system for exhaust valve fault identification based on proportional valve duty cycle according to claim 4, characterized in that: The water separator is connected to the hydrogen circulation device, and the water separator will send the discharged hydrogen back to the fuel cell stack through the hydrogen circulation device.

6. The system for exhaust valve fault identification based on proportional valve duty cycle according to claim 4, characterized in that: The hydrogen circulation device is either a hydrogen ejector or a hydrogen circulation pump.

7. The system for exhaust valve fault identification based on proportional valve duty cycle according to claim 4, characterized in that: The low operating point refers to the engine's operating condition under low current. The high operating point refers to the operating condition of the engine under high current.

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