CN113707919B - Method and system for distinguishing, regulating and controlling internal humidity of fuel cell system stack - Google Patents

Abstract

The invention belongs to the technical field of fuel cells, and discloses a method and a system for judging and regulating the internal humidity of a fuel cell system galvanic pile. The method for judging and regulating the internal humidity of the fuel cell system galvanic pile can basically judge the dry and wet conditions in the galvanic pile and make corresponding measures to regulate. The invention mainly aims at about 250 graphite electric piles. The problems that the system durability is reduced, the working performance is influenced and even the residual service life is shortened due to the fact that the existing proton exchange membrane fuel cell is frequently flooded and dried. The invention can more accurately adjust the optimal humidity in the galvanic pile, improve the performance of the galvanic pile and prolong the service life of the galvanic pile.

Description

Method and system for judging and controlling humidity inside a stack of a fuel cell system

technical field

The invention belongs to the technical field of fuel cells, and in particular relates to a method and a system for judging and regulating the internal humidity of a stack in a fuel cell system.

Background technique

At present, the proton exchange membrane fuel cell is a nonlinear complex system coupled with multiple physical fields. Among them, the proton exchange membrane has certain requirements on the humidity of the reaction gas. If the humidity is too high, water flooding will occur, and if the humidity is too low, membrane Dry phenomenon, water flooding and membrane dry phenomenon often occur in proton exchange membrane fuel cells, which will reduce the durability of the system, affect the working performance, and even shorten the remaining life.

Among them, water flooding will reduce the activity of the catalytic layer, accelerate the corrosion of materials and the loss of catalyst, reduce the active area, and even cause liquid water to accumulate in the gas flow channel, resulting in poor gas flow and seriously affecting the operation and performance of the proton exchange membrane fuel cell. Proton conduction in proton exchange membrane fuel cells requires water molecules as a carrier, so the proton conductivity will drop significantly when the membrane is dry, affecting the normal operation of the battery.

Through the above analysis, the problems and defects in the prior art are:

(1) Flooding and membrane drying often occur in existing proton exchange membrane fuel cells, which will reduce the durability of the system, affect the working performance, and even shorten the remaining life.

(2) The flooding of the existing proton exchange membrane fuel cell will reduce the activity of the catalytic layer, accelerate the corrosion of the material and the loss of the catalyst, reduce the active area, and even cause liquid water to accumulate in the gas flow channel, resulting in poor gas flow and seriously affecting Operation and performance of proton exchange membrane fuel cells.

(3) Proton conduction in existing proton exchange membrane fuel cells requires water molecules as a carrier, so the proton conductivity will drop significantly when the membrane dry occurs, affecting the normal operation of the battery.

The difficulty in solving the above problems and defects is: when the proton exchange membrane fuel cell is running, it is impossible to intuitively judge the dryness and humidity inside the stack, and thus it is impossible to accurately adjust the humidity inside the stack.

The significance of solving the above problems and defects is: more accurately adjust the optimum humidity inside the stack, and improve the performance and life of the stack.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a method and system for judging and controlling the internal humidity of a fuel cell system electric stack, and especially relates to a high-power fuel cell system electric stack internal humidity discrimination and control system based on CVM single-chip test voltage. control methods and systems.

The present invention is achieved in this way, a fuel cell system stack internal humidity discrimination and control method, the fuel cell system stack internal humidity discrimination and control method includes:

According to the characteristics of the stack, and according to the distribution of the CVM single-chip test voltage, the internal dryness and humidity of the stack are judged, and the internal humidity of the stack is adjusted by adjusting the operating conditions of the fuel cell system according to the determined dryness and humidity inside the stack.

Further, the method for judging and controlling the internal humidity of the fuel cell system stack includes the following steps:

Step 1: After the system is started, the stack operates normally;

Step 2, load the stack to adjust the reactant flow rate and the stack inlet and outlet pressure;

Step 3, analyze whether the single-chip voltage difference ΔU of the stack CVM is within the allowable range, if yes, return to step 2; if not, go to step 4; ΔU refers to the difference between the highest single-chip voltage and the lowest single-chip voltage of the stack ;

Step 4. When the single-chip voltage difference ΔU of the stack CVM exceeds the allowable range, analyze the single cells with lower single-chip voltage of the stack and their distribution positions in the stack. If they are only distributed at the entrance and exit of the stack, execute Step 5: If the performance of the stack is being reduced if it is distributed in multiple positions of the stack or at a position far from the entrance and exit of the stack, then perform step 18;

Step 5, open the exhaust valve continuously to purge the anode of the stack;

Step 6: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, and whether the exhaust valve discharges a lot of water. If so, it means that there is water flooding inside the stack, and the inside of the stack is wet; if If not, go to step seven;

Step seven, analyze whether the stack temperature T1 (actual stack water temperature) is lower than the temperature T2 (optimum stack water temperature) corresponding to the operating point, if yes, execute step eight; if not, execute step ten;

Step 8, reduce the load and increase the temperature to make the temperature T1=T2, and run for a period of time t;

Step 9: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range. If so, it means that the stack is too low to vaporize and discharge more water inside the stack, making the stack The inside is humid; if not, go to step 10;

Step 10: Increase the hydrogen-air pressure difference ΔP entering the stack within the allowable range, which can prevent the water in the cathode in the stack from penetrating into the anode, and run for a period of time t; ΔP is the difference between the pressure of hydrogen entering the stack and the pressure of air entering the stack;

Step 11: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range. If so, it means that the stack is partially humid due to too much water infiltrated from the cathode inside the stack to the anode; if not, Then execute step 12;

Step 12, increase the speed of the hydrogen circulation pump, increase the anode flow rate, and more fully discharge the water on the anode side, and run for a period of time t;

Step 13, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is due to the slow flow rate of the anode gas inside the stack and the moisture in it cannot be completely discharged. ; If not, go to step 14;

Step 14, increase the speed of the air compressor, increase the flow rate of the cathode to blow out the excess water in the stack, reduce the water from the cathode of the stack to the anode side, and run for a period of time t;

Step 15, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is caused by excessive water in the cathode inside the stack, which causes more water to penetrate into the anode, thus causing electric shock. Humidity inside the pile; if not, go to step 16;

Step sixteen, shorten the exhaust valve exhaust interval t1 (meaning that the exhaust valve is opened once every t1 time), or extend the exhaust valve exhaust duration t2 (meaning that the exhaust valve is opened every time t2), and run for a period of time t;

Step 17, the single-chip voltage difference ΔU of the stack CVM will gradually return to the allowable range, indicating that the stack is caused by the water accumulation inside the stack exceeding the water content of the membrane electrode of the stack due to the exhaust valve exhaust interval being too long Humidity phenomenon;

Step 18, analyze whether the stack temperature T1 is greater than the temperature T2 corresponding to the operating point, if yes, perform step 19; if not, perform step 21;

Step 19: Increase the speed of the cooling fan, increase the heat dissipation of the radiator, reduce the temperature of the stack to a corresponding temperature, make T1=T2, and run for a period of time t;

Step 20, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is dry due to excessive evaporation of water in the stack membrane electrode due to high temperature; if If not, go to step 21;

Step 21, increase the humidity of the air by spraying deionized water on the air pipeline externally, so that the air entering the anode of the stack is enough to wet the membrane electrode, and run for a period of time t;

Step 22, the extreme difference ΔU of the stack CVM single-chip voltage will gradually return to the allowable range, indicating that the membrane dry phenomenon caused by insufficient air humidification of the stack cathode;

Step 23, the humidity adjustment is completed.

Further, the method for judging and controlling the internal humidity of the fuel cell system stack is aimed at a 250-piece graphite stack with a size of 600mm*400mm*200mm.

Another object of the present invention is to provide a system for judging and regulating the internal humidity of a fuel cell system stack using the method for judging and regulating the internal humidity of a fuel cell system stack.

Another object of the present invention is to provide an application of the above-mentioned fuel cell system stack internal humidity discrimination and control system in a proton exchange membrane fuel cell.

Another object of the present invention is to provide a computer device, the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following step:

Through the characteristics of the stack, the internal dryness and humidity of the stack can be basically judged by analyzing the distribution of the CVM single-chip test voltage, and the internal humidity of the stack can be quickly adjusted by adjusting the operating conditions of the system.

Another object of the present invention is to provide a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the processor performs the following steps:

Through the characteristics of the stack, the internal dryness and humidity of the stack can be basically judged by analyzing the distribution of the CVM single-chip test voltage, and the internal humidity of the stack can be quickly adjusted by adjusting the operating conditions of the system.

Another object of the present invention is to provide a computer program product stored on a computer-readable medium, including a computer-readable program, which, when executed on an electronic device, provides a user input interface to apply the fuel cell system stack Internal humidity discrimination and control system.

Another object of the present invention is to provide a computer-readable storage medium, which stores instructions, and when the instructions are run on a computer, the computer can apply the system for judging and regulating the internal humidity of the fuel cell stack.

Another object of the present invention is to provide an information and data processing terminal, which is used to realize the above-mentioned system for judging and regulating the internal humidity of the fuel cell stack.

Combining all the above-mentioned technical solutions, the advantages and positive effects of the present invention are: the method for judging and controlling the internal humidity of the stack in the fuel cell system provided by the present invention can basically judge the dry and wet conditions inside the stack, and take corresponding measures to control the humidity inside the stack. Adjustment. The present invention is mainly aimed at about 250 graphite electric stacks with a size of 600mm*400mm*200mm.

The invention proposes a simple and flexible method and control method for judging the internal humidity of a stack based on the CVM single-chip test voltage. Through the characteristics of a certain electric stack, it can be more intuitively judged according to the distribution of the CVM single-chip test voltage. The dry and wet conditions inside the stack can be quickly adjusted by adjusting the operating conditions of the system to quickly adjust the humidity inside the stack. The invention solves the problems that the durability of the system is reduced, the work performance is affected, and even the remaining life is shortened due to the phenomenon of water flooding and membrane drying that often occur in the existing proton exchange membrane fuel cells.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is a flow chart of a method for judging and controlling the internal humidity of a fuel cell system stack provided by an embodiment of the present invention.

Fig. 2 is a histogram of the inspection voltage of a stack single chip provided by an embodiment of the present invention.

Among them, the position of the ellipse circle in Figure 2(a) is close to the inlet and outlet of the stack, and the single chip voltage at this position is low, indicating that the humidity of the stack is too high and water blocking occurs. Figure 2(b) The monolithic voltage at multiple positions of the stack is low, indicating that the stack shows that the humidity of the stack is low and the film dry phenomenon occurs. By adjusting the operating conditions of the stack to adjust the humidity of the stack, the voltage of the adjusted stack is relatively uniform, as shown in Figure 2(c).

detailed description

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Aiming at the problems existing in the prior art, the present invention provides a method and system for judging and regulating the internal humidity of a fuel cell system stack. The present invention will be described in detail below with reference to the accompanying drawings.

The method for judging and controlling the internal humidity of a fuel cell system stack provided by an embodiment of the present invention includes: using the characteristics of the stack and analyzing the distribution of the CVM single-chip test voltage to basically determine the dryness and humidity inside the stack, and can adjust the humidity of the stack by adjusting the humidity of the stack. Operating conditions to quickly adjust the humidity inside the stack.

The technical solutions of the present invention will be further described below in conjunction with the embodiments.

The invention proposes a method for judging the internal humidity of the electric stack based on the CVM single-chip test voltage, which can basically judge the dry and wet conditions inside the electric stack, and take corresponding measures to adjust.

As shown in Figure 1, the method for judging and controlling the internal humidity of a stack based on the CVM single-chip test voltage provided by the embodiment of the present invention includes:

S1, after the system is started, the stack operates normally;

S2, load the stack to adjust the reactant flow rate and the stack inlet and outlet pressure;

S3, analyze whether the single chip voltage difference of the stack CVM is within the allowable range, if yes, return to S2, if not, proceed to S4;

S4. When the extreme difference in the single-chip voltage of the stack CVM exceeds the allowable range, analyze where the single cells with the lowest single-chip voltage of the stack are distributed in the stack. If they are only distributed at the entrance and exit of the stack, then Go to S5; if it is distributed in multiple positions of the stack or at a position far from the entrance and exit of the stack, and the performance of the stack is being reduced, go to S23;

S5, continue to open the exhaust valve to purge the anode of the stack;

S6, analyze whether the single chip voltage difference ΔU of the stack CVM is restored within the allowable range, and whether the exhaust valve discharges more water, if yes, go to S7, if not, go to S8;

S7, indicating that there is water flooding inside the stack, and the inside of the stack is wet;

S8, analyze whether the stack temperature T1 is lower than the temperature T2 corresponding to the operating point, if yes, proceed to S9; if not, proceed to S12;

S9, reduce load and heat up, make temperature T1=T2, run for a period of time t;

S10, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if yes, go to S11, if not, go to S12;

S11, indicating that the stack is due to the low temperature of the stack, so that more water inside the stack cannot be vaporized and discharged, which makes the inside of the stack humid;

S12, increase the hydrogen-air pressure difference ΔP into the stack within the allowable range, which can inhibit the water in the cathode in the stack from penetrating into the anode, and run for a period of time t;

S13, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if yes, go to S14, if not, go to S15;

S14, indicating that the stack is due to the partial humidity caused by too much water from the cathode inside the stack to the anode;

S15, increase the speed of the hydrogen circulation pump, increase the flow rate of the anode, more fully discharge the water on the anode side, and run for a period of time t;

S16, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if yes, go to S17, if not, go to S18;

S17, indicating that the stack is due to the slow flow rate of the anode gas inside the stack, which leads to the partial humidity phenomenon caused by the inability to completely discharge the water;

S18, increase the speed of the air compressor, increase the flow rate of the cathode to purge out the excess water in the stack, reduce the water from the cathode of the stack to the anode side, and run for a period of time t;

S19, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if yes, return to S20, if not, proceed to S21;

S20, indicating that the stack is caused by excessive moisture in the cathode inside the stack, causing more water to penetrate into the anode, resulting in partial humidity inside the stack;

S21, shorten the exhaust valve exhaust interval t1, or extend the exhaust valve exhaust duration t2, and run for a period of time t;

S22, the voltage range ΔU of the stack CVM single chip will gradually return to the allowable range, indicating that the stack is due to the excessive humidity caused by the water accumulation inside the stack exceeding the water content of the membrane electrode of the stack due to the exhaust valve exhaust interval being too long Phenomenon;

S23, analyze whether the stack temperature T1 is greater than the temperature T2 corresponding to the operating point, if yes, proceed to S24; if not, proceed to S27;

S24, increasing the rotating speed of the cooling fan, increasing the heat dissipation capacity of the radiator, reducing the temperature of the stack to a corresponding temperature, making T1=T2, and running for a period of time t;

S25, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if yes, proceed to S26, if not, proceed to S27;

S26, indicating that the stack is a film dry phenomenon caused by excessive evaporation of water in the stack membrane electrode due to excessive temperature;

S27, increase the humidity of the air by spraying deionized water to the air pipeline externally, so that the air entering the anode of the stack is enough to wet the membrane electrode, and run for a period of time t;

S28, the single-chip voltage difference ΔU of the stack CVM will gradually return to the allowable range, indicating that the membrane dryness phenomenon is caused by insufficient air humidification of the stack cathode;

S29, the humidity adjustment is completed.

The present invention is mainly aimed at about 250 graphite electric stacks with a size of 600mm*400mm*200mm.

The invention proposes a simple and flexible method and control method for judging the internal humidity of a stack based on the CVM single-chip test voltage, and basically distinguishes the stack by analyzing the distribution of the CVM single-chip test voltage through the characteristics of a certain stack The internal dry and wet conditions, and can quickly adjust the internal humidity of the stack by adjusting the operating conditions of the system.

Figure 2 is a histogram of the inspection voltage of a stack single chip.

The position of the ellipse circle in Figure 2(a) is close to the inlet and outlet of the stack. The voltage of the single chip at this position is low, indicating that the humidity of the stack is too high and water blocking occurs.

Figure 2(b) The monolithic voltage at multiple positions of the stack is low, indicating that the stack shows that the humidity of the stack is low and the film dry phenomenon occurs.

By adjusting the operating conditions of the stack to adjust the humidity of the stack, the voltage of the adjusted stack is relatively uniform, as shown in Figure 2(c).

In the description of the present invention, unless otherwise stated, the meaning of "plurality" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer" , "front end", "rear end", "head", "tail", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than Nothing indicating or implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation should therefore not be construed as limiting the invention. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

In the above embodiments, all or part of them may be implemented by software, hardware, firmware or any combination thereof. When implemented wholly or partly in the form of a computer program product, said computer program product comprises one or more computer instructions. When the computer program instructions are loaded or executed on the computer, the processes or functions according to the embodiments of the present invention will be generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website, computer, server or data center Transmission to another website site, computer, server or data center by wired (eg coaxial cable, fiber optic, digital subscriber line (DSL) or wireless (eg infrared, wireless, microwave, etc.)). The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or a data center integrated with one or more available media. The available medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, DVD), or a semiconductor medium (for example, a Solid State Disk (SSD)).

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope disclosed in the present invention, whoever is within the spirit and principles of the present invention Any modifications, equivalent replacements and improvements made within shall fall within the protection scope of the present invention.

Claims (4)

1. A fuel cell system stack internal humidity discrimination and control method, characterized in that the fuel cell system stack internal humidity discrimination and control method comprises: According to the characteristics of the stack, and according to the distribution of the CVM single-chip test voltage, the internal dryness and humidity of the stack are judged, and the internal humidity of the stack is adjusted by adjusting the operating conditions of the fuel cell system according to the determined dryness and humidity inside the stack; The method for judging and controlling the internal humidity of the stack in the fuel cell system includes the following steps: Step 1: After the system is started, the stack operates normally; Step 2, load the stack to adjust the reactant flow rate and the stack inlet and outlet pressure; Step 3, analyze whether the single-chip voltage difference ΔU of the stack CVM is within the allowable range, if yes, return to step 2; if not, perform step 4; Step 4: When the single-chip voltage difference ΔU of the stack CVM exceeds the allowable range, analyze the distribution position of the cells with lower single-chip voltage in the stack. If they are only distributed at the inlet and outlet positions at both ends of the stack, then Execute step 5; if the performance of the stack is being reduced if it is distributed in multiple positions of the stack or far from the entrance and exit of the stack, then perform step 18; Step 5, open the exhaust valve continuously to purge the anode of the stack; Step 6: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, and whether the exhaust valve discharges a lot of water. If so, it means that there is water flooding inside the stack, and the inside of the stack is wet; if If not, go to step seven; Step 7, analyze whether the stack temperature T1 is lower than the temperature T2 corresponding to the operating point, if yes, perform step 8; if not, perform step 10; Step 8, reduce the load and heat up, so that the temperature T1 rises to T2, and run for a period of time t; Step 9: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range. If so, it means that the stack is too low to vaporize and discharge more water inside the stack, making the stack The inside is humid; if not, go to step 10; Step 10: Increase the difference ΔP between the gas pressure on the anode side and the gas pressure on the cathode side within the allowable range, so as to prevent the water in the cathode in the stack from penetrating into the anode, and run for a period of time t; Step 11: Analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range. If so, it means that the stack is partially humid due to too much water infiltrated from the cathode inside the stack to the anode; if not, Then execute step 12; Step 12, increase the speed of the hydrogen circulation pump, increase the anode flow rate, and more fully discharge the water on the anode side, and run for a period of time t; Step 13, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is due to the slow flow rate of the anode gas inside the stack and the moisture in it cannot be completely discharged. ; If not, go to step 14; Step 14, increase the speed of the air compressor, increase the flow rate of the cathode to blow out the excess water in the stack, reduce the water from the cathode of the stack to the anode side, and run for a period of time t; Step 15, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is caused by excessive water in the cathode inside the stack, which causes more water to penetrate into the anode, thus causing electric shock. Humidity inside the pile; if not, go to step 16; Step sixteen, shorten the exhaust valve exhaust interval t1, or extend the exhaust valve exhaust duration t2, and run for a period of time t; Step 17, the single-chip voltage difference ΔU of the stack CVM will gradually return to the allowable range, indicating that the stack is caused by the water accumulation inside the stack exceeding the water content of the membrane electrode of the stack due to the exhaust valve exhaust interval being too long Humidity phenomenon; Step 18, analyze whether the stack temperature T1 is greater than the temperature T2 corresponding to the operating point, if yes, perform step 19; if not, perform step 21; Step nineteen, increase the speed of the cooling fan, increase the heat dissipation of the radiator, reduce the stack temperature T1 to T2, and run for a period of time t; Step 20, analyze whether the single-chip voltage difference ΔU of the stack CVM is restored within the allowable range, if so, it means that the stack is dry due to excessive evaporation of water in the stack membrane electrode due to high temperature; if If not, go to step 21; Step 21, increase the humidity of the air by spraying deionized water on the air pipeline externally, so that the air entering the cathode of the stack is enough to wet the membrane electrode, and run for a period of time t; Step 22, the extreme difference ΔU of the stack CVM single-chip voltage will gradually return to the allowable range, indicating that the membrane dry phenomenon caused by insufficient air humidification of the stack cathode; Step 23, the humidity adjustment is completed; The method for judging and controlling the internal humidity of the fuel cell system stack is aimed at a 250-piece graphite stack with a size of 600mm*400mm*200mm. 2. A fuel cell system stack internal humidity discrimination and control system applying the fuel cell system stack internal humidity discrimination and control method according to claim 1. 3. An application of the fuel cell system stack internal humidity discrimination and control system as claimed in claim 2 in a proton exchange membrane fuel cell. 4. An information data processing terminal, characterized in that the information data processing terminal is used in the fuel cell system stack internal humidity discrimination and control system according to claim 2.

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