Fuel cell

Abstract

The utility model relates to a fuel cell which comprises a gas supply pipeline, an electromagnetic valve arranged on the gas supply pipeline, and an electromagnetic valve driving circuit used for driving the electromagnetic valve, the electromagnetic valve is provided with a coil and an elastic sealing ring, and the driving circuit comprises a pulse generating circuit connected with a power supply and the electromagnetic valve, the electromagnetic valve is driven by the power supply to generate pulse driving voltage, the pulse driving voltage has a frequency, and the power supply intermittently supplies power to a coil of the electromagnetic valve at the corresponding frequency; and the discharge loop is connected with a coil of the electromagnetic valve and is used for releasing inductance energy of the coil when the power supply stops supplying power to the electromagnetic valve, so that the coil generates electromagnetic force for maintaining the opening or closing state of the electromagnetic valve. Starting of the electromagnetic valve is maintained at low power, heating of the coil of the electromagnetic valve is reduced, the influence of temperature on the coil and the sealing ring is reduced, and the service life of the electromagnetic valve is prolonged.

Description

Technical Field

[0001] The utility model relates to a fuel cell. Background Art

[0002] In the current fuel cell system, the solenoid valve is directly driven by a power supply. Although this driving method is simple, there is a serious problem, that is, long-term use will cause the solenoid valve to heat up, thus affecting its service life.

[0003] When the solenoid valve is directly driven by a power supply, an electric current will generate a magnetic field through the coil, thereby causing the iron core of the solenoid valve to act. However, in this process, there is a certain resistance in the coil, resulting in heat generation when the electric current passes through. If the solenoid valve is used for a long time, these heats will accumulate continuously, causing the coil temperature to rise, thereby affecting the performance and service life of the solenoid valve. Summary of the Utility Model

[0004] In the current fuel cell system, the solenoid valve is directly driven by a power supply, and the heat generation problem caused by long-term operation cannot be ignored. To solve this problem, the utility model proposes a fuel cell with a new solenoid valve driving method, aiming to reduce the heat generation of the solenoid valve in the long-term working state, extend its service life, and improve the overall performance of the fuel cell.

[0005] A fuel cell provided by the utility model includes a gas supply pipeline, a solenoid valve is arranged on the gas supply pipeline of the fuel cell, and the opening or closing of the gas supply pipeline is controlled by the movement of the solenoid valve. A coil and an elastic sealing ring are arranged on the solenoid valve, and a solenoid valve driving circuit for driving the solenoid valve, and the driving circuit includes:

[0006] A pulse generating circuit, which is connected to a power supply and generates a pulse driving voltage under the drive of the power supply;

[0007] The pulse generating circuit is connected to the coil of the solenoid valve, and according to the frequency of the pulse driving voltage, the power supply supplies power to the coil of the solenoid valve intermittently at a corresponding frequency;

[0008] A discharge circuit, which is connected to the coil of the solenoid valve. When the power supply stops supplying power to the solenoid valve, the discharge circuit is used to release the inductive energy of the coil, so that the coil generates an electromagnetic force to maintain the open or closed state of the solenoid valve.

[0009] Further, the pulse generating circuit includes: an oscillator and a pulse width modulation circuit;

[0010] The oscillator is connected to the power supply through the pulse width modulation circuit. The power supply generates a trigger signal after passing through the pulse width modulation circuit. The trigger signal is received by the oscillator to generate a pulse signal. The power supply generates the pulse drive voltage under the control of the pulse signal.

[0011] The trigger signal is a continuously changing voltage, and the value of the voltage includes at least being less than 1 / 3 of the power supply voltage value and greater than 2 / 3 of the power supply voltage value.

[0012] Further, the oscillator is an NE555 timer, which includes pins 1 to 8. Among them, pin 1 is grounded, pins 4 and 8 are connected to the power supply, and pin 5 is left floating.

[0013] The pulse width modulation circuit includes a first resistor and a first capacitor connected in sequence to the positive pole of the power supply. One end of the first capacitor far from the positive pole of the power supply is grounded. The node voltage between the first resistor and the first capacitor is the trigger signal.

[0014] The trigger signal is respectively connected to the NE555 timer through pins 2 and 6 for logic processing, and then a corresponding pulse signal is output from pin 3 of the NE555 timer.

[0015] The node between the first resistor and the first capacitor is also connected to pin 7 of the NE555 timer through a second resistor.

[0016] Further, the pulse generation circuit includes an oscillator and a pulse width modulation circuit. The pulse width modulation circuit enables the duty cycle of the pulse signal to be adjustable. When the solenoid valve is opened, the pulse signal has a first duty cycle. When the solenoid valve remains open after being opened, the pulse signal has a second duty cycle, where the second duty cycle is less than the first duty cycle.

[0017] Further, the voltage value of the trigger signal is configured as follows: when the first capacitor starts to charge, its value is less than 1 / 3 of the power supply voltage; when the first capacitor discharges, its value is greater than 2 / 3 of the power supply voltage.

[0018] Further, the first resistor is an adjustable resistor, which is provided with a switch for the user to adjust its resistance value.

[0019] Further, the pulse generation circuit further includes a switching tube, the switching tube is connected in series with the coil, and the discharge circuit includes at least one third diode connected in parallel with the coil, so that when the switching tube is turned off, the current in the coil discharges through the third diode.

[0020] Further, the pulse generating circuit further includes a third resistor and a fourth resistor connected in series. The third resistor is connected to the pulse signal, the fourth resistor is grounded, and the node between the third resistor and the fourth resistor is connected to the control electrode of the switching tube.

[0021] Further, within a period of one of the pulse signals, the turn-off time of the switching tube is less than or equal to the time for the coil inductance energy to be completely released, such that the minimum current Im flowing through the coil during the turn-off time of the switching tube is greater than 15% of the maximum current Id flowing through the coil when the switching tube is turned on.

[0022] Further, a first diode is connected between the first resistor and the first capacitor, and the anode of the first diode is close to the positive electrode side of the power supply;

[0023] The second resistor is connected to the cathode of the second diode, and the anode of the second diode is connected to the cathode of the first diode.

[0024] Further, the positive electrode of the power supply is grounded through a fifth resistor and a sixth resistor, and the node between the fifth resistor and the sixth resistor is connected to the first resistor

[0025] The present utility model has the following beneficial effects:

[0026] The heat generation phenomenon of the solenoid valve after long-term operation is reduced, the problems of performance degradation and shortened lifespan of the solenoid valve caused by overheating are avoided, and a strong guarantee is provided for the stable operation of the fuel cell;

[0027] By adjusting the resistance value, the duty cycle of the pulse drive voltage output by the drive circuit is adjusted, so that the drive circuit can be adapted to various types of solenoid valves, and the method of adjusting the duty cycle is simple and flexible. Description of the Drawings

[0028] Figure 1 It is a structural block diagram of a fuel cell provided by the present utility model;

[0029] Figure 2 It is a circuit diagram of a drive circuit provided by the present utility model;

[0030] Figure 3 It is the working condition of the solenoid valve under pulse drive voltages with different duty cycles;

[0031] Figure 4 It is a pulse drive voltage waveform diagram provided by an embodiment of the present utility model;

[0032] Figure 5 It is a pulse drive voltage waveform diagram provided by another embodiment of the present utility model;

[0033] Figure 6The waveform diagram of the pulse driving voltage and the current in the coil provided by an embodiment of the present utility model. Detailed implementation manners

[0034] A solenoid valve is a device that controls the flow of gas using electromagnetic principles. As Figure 1 shown, the hydrogen source 300 is connected to the solenoid valve 101 through the gas supply pipeline 103. The solenoid valve 101 is connected to the hydrogen inlet 102 of the fuel cell 100 through the gas supply pipeline 104. By controlling the opening and closing of the solenoid valve 101, the automatic control of the hydrogen supply to the fuel cell 100 can be achieved. When the solenoid valve 101 is powered on, its valve core will be attracted by the electromagnet, making the gas supply pipelines 103 and 104 conduct, and hydrogen can flow from the hydrogen source 300 to the hydrogen inlet 102 of the fuel cell 100. When the solenoid valve 101 is powered off, the valve core will be bounced back by the spring, and the gas supply pipelines 103 and 104 will be blocked, stopping the hydrogen supply. By controlling the opening and closing of the solenoid valve 101, the precise control of the gas supply between the hydrogen source 300 and the fuel cell 100 can be realized, thereby ensuring the normal operation of the fuel cell 100.

[0035] For pneumatic solenoid valves, different temperature ranges will have different effects on their performance. Generally speaking, the operating temperature range of pneumatic solenoid valves is from -10°C to 80°C. At different temperatures, the stability, applicability, etc. of pneumatic solenoid valves are different. In a high-temperature environment, problems such as deformation of the valve body and weakening of the sealing performance of pneumatic solenoid valves will occur. Since heat is generated when pneumatic solenoid valves work, if it is necessary to use pneumatic solenoid valves in a high-temperature environment, the pneumatic solenoid valves need to be cooled down. This application uses a cooling circuit control board, as Figure 2 shown, the circuit control board includes a driving circuit 200 for driving the solenoid valve. The circuit control board is powered by an external power supply P to generate a corresponding pulse control voltage to control the on and off of the solenoid valve 101.

[0036] Taking the type B solenoid valve of the VX21 model of SMC Corporation as an example, the normal operating environment temperature of the coil of this type of solenoid valve is -20°C to 60°C. The temperature at which the fuel cell 100 operates is usually around 40°C, which is already close to the upper limit of the temperature range for using the solenoid valve. If the solenoid valve is powered on for a long time, the heat generated by the solenoid valve itself is relatively high, which will not only have a serious impact on the working state of the solenoid valve coil, but even cause damage to the components of the solenoid valve. In addition, long-term high temperature will also accelerate the aging and damage of the solenoid valve sealing ring, thereby affecting the sealing performance and service life of the solenoid valve.

[0037] Therefore, the fuel cell 100 provided by the present application uses PWM (Pulse Width Modulation) technology to control the solenoid valve 101. The fuel cell 100 includes a gas supply pipeline 104, and the solenoid valve 101 is arranged on the gas supply pipeline 104. The opening or closing of the gas supply pipeline 104 is controlled by the movement of the solenoid valve 101. The solenoid valve 101 includes a coil and an elastic sealing ring. The solenoid valve 101 is driven by a driving circuit 200, and the driving circuit 200 is electrically connected to the coil of the solenoid 101 through a line 105.

[0038] As Figure 2 shown, the driving circuit 200 includes:

[0039] A pulse generation circuit 201, which is connected to a power supply P and is driven by the power supply P to generate a pulse driving voltage. The pulse generation circuit 201 is also connected to the coil of the solenoid valve 101; according to the frequency of the pulse driving voltage, the power supply P intermittently supplies power to the coil of the solenoid valve 101 at a corresponding frequency;

[0040] A discharge circuit 202, which is connected to the coil of the solenoid valve 101. When the power supply P stops supplying power to the solenoid valve 101, the discharge circuit 202 is used to release the inductive energy of the coil, so that the coil generates an electromagnetic force to maintain the open or closed state of the solenoid valve 101.

[0041] Due to the intermittent power supply of the power supply P, the solenoid valve 101 can maintain normal opening at a lower working power, thereby reducing the heat generated when the solenoid valve 101 works. And under the pulse driving voltage, each type of solenoid valve 101 has a minimum working power, and this minimum working power can be achieved by adjusting the duty cycle of the pulse driving voltage, and pulse width modulation technology is used to generate a pulse driving voltage with a suitable duty cycle. The suitable duty cycle described in the present application is the duty cycle value independently set by the user according to his own functional requirements. It should be noted that at a certain power supply P voltage, the smaller the duty cycle, the shorter the power supply duration of the power supply P in a pulse cycle, that is, the smaller the working power obtained by the solenoid valve 101 during operation and the lower the energy consumption. In addition, a low duty cycle means lower stability in maintaining the opening of the solenoid valve 101, and the thrust generated by the current obtained by the solenoid valve 101 from the power supply P is less. When the duty cycle is too low, the solenoid valve 101 cannot maintain the open state.

[0042] In order to obtain the optimal duty cycle value, the present application records the tests on the effect of maintaining the opening of the solenoid valve 101 under different duty cycles. During the test, the temperature of the solenoid valve 101 is also tested. The rated voltage of the solenoid valve used in this test case is 24V, and the power supply P of 24V is used for power supply.

[0043] When the solenoid valve is directly connected to the power supply P, for the solenoid valve with a rated voltage of 24V used in this example, its working power after being energized is 4.76W, and the temperature of the solenoid valve rises and the working power decreases within a short period of energization. Specifically, before energization, the temperature of the solenoid valve is 12.9 °C, and after 30 minutes of energization, the temperature of the solenoid valve rises to 38.4 °C, with a temperature increase of 25.5 °C.

[0044] This application records a test result where a power supply P of 24V supplies power to the solenoid valve 101 through the drive circuit 200. The test results show that the power supply P supplying power to the solenoid valve 101 through this drive circuit 200 can effectively reduce the heat generation of the solenoid valve 101. Moreover, by adjusting the pulse drive voltage with different duty cycles output by the drive circuit 200, the solenoid valve 101 can maintain the open state at different working powers. This application tests the solenoid valve 101 for maintaining the open state, temperature, and working power under pulse drive voltages with different duty cycles. The relevant data is as Figure 3 shown. It can be obtained from Figure 3 that the solenoid valve with a rated voltage of 24V can maintain the open state under a pulse drive voltage with a duty cycle of 17.19%, and at this time, the corresponding working power is the lowest, only 0.74W.

[0045] To improve the stability of the open state, the duty cycle of the pulse drive voltage can be further increased. When the duty cycle is increased to 24.82%, the working power of the solenoid valve is only 0.86W. Compared with 4.76W when directly connected to the power supply P, the energy consumption is also significantly reduced. By recording the temperature change of the solenoid valve 101 after working at a working power of 0.86W for a period of time, the following results are obtained: before energization, the temperature of the solenoid valve is 15.4 °C, and after 30 minutes of energization, the temperature of the solenoid valve is only 17.0 °C, with a temperature increase of 1.6 °C. It can be seen that the drive circuit 200 has the effect of reducing energy consumption and reducing the heat generation of the solenoid valve due to the output of a low-duty-cycle drive voltage.

[0046] Different from maintaining the open state of the solenoid valve, due to the self-inductance phenomenon of the solenoid valve coil when it is opened, the coil responds slowly to the pulse drive voltage with a low duty cycle and may even not be able to open normally. Therefore, a pulse drive voltage with a higher duty cycle is required to drive the solenoid valve when it is opened. To ensure the normal opening of the solenoid valve, the duty cycle is often adjusted to a value greater than that for maintaining its normal open state. Generally, a pulse drive voltage with a duty cycle greater than 24.82% as shown in Figure 4 is used to drive the solenoid valve. After the solenoid valve is opened, using a pulse drive voltage with a large duty cycle to maintain the open state will undoubtedly cause energy waste.

[0047] To overcome this defect, this application designs the drive circuit 200 to have the function of adjusting the duty cycle. As shown inFigure 5 As shown, when the solenoid valve is opened, a pulse drive voltage with a first duty cycle D1 is output and lasts for a period of time T D1 , after the solenoid valve is opened, a pulse drive voltage with a second duty cycle D2 lower than the first duty cycle D1 is output, which is used to maintain the solenoid valve in the open state for the opening time T D2 The opening state within. Where the time T D1 can be within 10 seconds or even shorter, while the time T D2 can be several hours or even longer. Also, considering that the user needs to adjust the duty cycle of the pulse drive voltage according to the power supply size and the solenoid valve type, the drive circuit 200 can also be applicable to power supplies of various specifications and various types of solenoid valves. The user only needs to adjust the duty cycle to achieve adaptation to different power supplies and / or different types of solenoid valves.

[0048] Specifically, the pulse generation circuit 201 includes: an oscillator 2012 and a pulse width modulation circuit 2011. The oscillator 2012 is connected to the power supply P through the pulse width modulation circuit 2011. The power supply P generates a trigger signal after passing through the pulse width modulation circuit 2011. The trigger signal is received by the oscillator 2012 to generate a pulse signal. The power supply generates the pulse drive voltage under the control of the pulse signal. The frequency and duty cycle of the pulse drive voltage are equivalent to the frequency and duty cycle of the pulse signal.

[0049] Further, in this example, the oscillator 2012 is an NE555 timer, which includes pins 1 to 8. Among them, pin 1 is grounded, pins 4 and 8 are connected to the power supply P, pin 5 is floating, and the power supply voltage Vcc can be selected as 24V. The internal circuit of the NE555 timer includes two voltage comparators, which respectively compare the received trigger signal with the trigger voltage 1 / 3Vcc and the threshold voltage 2 / 3Vcc. The trigger signal is configured as a continuously changing voltage, and the value of the voltage at least includes less than 1 / 3Vcc and greater than 2 / 3Vcc. After the NE555 timer receives trigger signals with different voltage values, corresponding high and low levels are output.

[0050] The pulse width modulation circuit 2011 includes a first resistor R1 and a first capacitor C1 connected in sequence to the positive pole of the power supply P. One end of the first capacitor C1 far from the positive pole of the power supply P is grounded. The node voltage between the first resistor R1 and the first capacitor C1 is the trigger signal; and the voltage value of the trigger signal is configured as: when the first capacitor C1 starts to charge, its value is less than 1 / 3Vcc; when the first capacitor C1 discharges, its value is greater than 2 / 3Vcc.

[0051] The trigger signal is respectively input into the NE555 timer through the second pin and the sixth pin for logical processing, and then a corresponding pulse signal is output from the third pin of the NE555 timer;

[0052] The node between the first resistor R1 and the first capacitor C1 is also connected to the seventh pin of the NE555 timer through a second resistor R2.

[0053] Since the voltage on the first capacitor C1 cannot change suddenly, that is, the initial level of the second pin is a low potential less than 1 / 3Vcc, which makes the NE555 timer set, and the third pin presents a high level; then the first capacitor C1 starts to charge, and the charging time is t 充 = 0.7R1·C1. When the voltage charges to higher than the threshold level 2 / 3Vcc, the NE555 timer resets, and the third pin turns to a low level. At this time, the first capacitor C1 starts to discharge, and the discharge time t 放 = 0.7R2·C1. Then the oscillation period t of the pulse signal = t 充 + t 放 , and the duty cycle is D = t 充 / t = R1 / (R1 + R2);

[0054] Among them, R1 and R2 are the resistance values of the first resistor R1 and the second resistor R2 respectively, and C1 is the capacitance value of the first capacitor C1. From the above calculation process, it can be seen that the frequency 1 / t or the period t of the pulse signal can be changed by adjusting the values of R1, R2 or C1, and adjusting R1 or R2 can adjust the duty cycle D of the output pulse signal.

[0055] Therefore, the first resistor R1 can be set as a variable resistor, which is set to have a switch for the user to adjust its resistance value. The user can adjust the size of the first resistor R1 according to needs to adjust the duty cycle D of the pulse signal.

[0056] Preferably, a first diode D1 is connected between the first resistor R1 and the first capacitor C1, and the anode of the first diode D1 is close to the positive electrode side of the power supply P;

[0057] The second resistor R2 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is connected to the cathode of the first diode D1. When the first capacitor C1 discharges, the current enters the seventh pin through the second diode D2 to complete the discharge. At this time, the first diode D1 is in a cut-off state, which can prevent the discharge current from flowing into the power supply P.

[0058] Furthermore, the pulse generation circuit 201 further includes a switching transistor Q, which is serially connected to the coil of the solenoid valve 101. The discharge loop 202 includes at least one third diode D3 connected in parallel with the coil, such that when the switching transistor Q is turned off, the current in the coil discharges through the third diode D3, thereby generating a magnetic field to maintain the opening of the solenoid valve. And, within a period of one said pulse signal, the turn-off time of the switching transistor Q is less than or equal to the time when the inductive energy of the coil is completely released, that is, the release of the inductive energy of the coil can be maintained until the power supply P of the next cycle is turned on. After the power supply P is turned on, a magnetic field can continue to be generated in the coil through the power supply P to maintain the open state of the solenoid valve. As Figure 6 shown, before t1, the switching transistor Q is turned on. Under the drive of the pulse drive voltage, the current in the coil rapidly increases, and the corresponding driving force on the solenoid valve also increases synchronously until the current reaches the maximum value Id. Between t1 and t2, the switching transistor Q is turned off, and the current in the coil continues to flow through the parallel diode D3 and the current slowly decreases until the current decreases to the minimum value Im that can maintain the open state at time t2, and the corresponding driving force also drops to the minimum. As long as Im is more than 15% of Id, it can ensure that the driving force is not too low to cause the valve to close. The prior art uses a long-term power-on mode, so the heating power is maintained at the maximum value Id 2 R L (R L is the coil resistance). Under the drive current as shown in the present invention Figure 6 shown, since the drive and freewheeling currents are basically less than Id, the overall power consumption of the solenoid valve 101 is much less than that of the prior art. In addition, during the process of current increase and decrease, most of the energy becomes the magnetic field radiated outwards and is consumed in the surrounding space, and only part of the power is finally consumed as heat on the coil. Therefore, the heating power on the coil is only less than 25% of the original power Id 2 R L . The switching transistor Q can be an NPN-type triode, whose base is connected to the pulse signal, the emitter is grounded, and the collector is connected to the solenoid valve coil. The conduction and turn-off of the switching transistor Q are controlled by the pulse signal received by the base. When it is conducting, the power supply supplies power to the solenoid valve, and when it is turned off, the power supply stops supplying power, thereby controlling the power supply to output a pulse drive voltage with a specific duty cycle and frequency.

[0059] Preferably, the pulse generation circuit 201 further includes a third resistor R3 and a fourth resistor R4 connected in series. The third resistor R3 is connected to the pulse drive voltage, and the fourth resistor R4 is grounded. By grounding through the fourth resistor 4, a ground safety protection is provided. The node between the third resistor R3 and the fourth resistor R4 is connected to the control electrode (base) of the switching transistor Q.

[0060] Preferably, the positive electrode of the power supply P is grounded through a fifth resistor R5 and a sixth resistor R6, and is grounded through the sixth resistor 6 to provide a grounding safety protection. The node between the fifth resistor R5 and the sixth resistor R6 is connected to the first resistor R1.

[0061] In summary, the present application uses the drive circuit to control the opening and closing of the solenoid valve to control the gas supply between the hydrogen source and the fuel cell, ensuring the normal operation of the fuel cell; and by changing the duty cycle of the pulse drive voltage output by the drive circuit, it realizes maintaining the start of the solenoid valve with lower power, reducing the heating of the solenoid valve coil; effectively reducing the influence of temperature on the coil and the sealing ring from the root, increasing the service life of the solenoid valve, and to a certain extent also expanding the temperature range of use of the solenoid valve.

[0062] Although the content of the present utility model has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present utility model. After those skilled in the art have read the above content, various modifications and alternatives to the present utility model will be obvious. Therefore, the protection scope of the present utility model should be defined by the appended claims.

Claims

1. A fuel cell, characterized in that, The fuel cell includes a gas supply line, and a solenoid valve is arranged on the gas supply line of the fuel cell. The opening or closing of the gas supply line is controlled by the movement of the solenoid valve. A coil and an elastic sealing ring are arranged on the solenoid valve, and a solenoid valve driving circuit for driving the solenoid valve. The driving circuit includes: A pulse generation circuit, which is connected to a power supply and generates a pulse driving voltage under the drive of the power supply; The pulse generation circuit is connected to the coil of the solenoid valve. According to the frequency of the pulse driving voltage, the power supply intermittently supplies power to the coil of the solenoid valve at a corresponding frequency; A discharge circuit, which is connected to the coil of the solenoid valve. When the power supply stops supplying power to the solenoid valve, the discharge circuit is used to release the inductive energy of the coil.

2. The fuel cell according to claim 1, wherein The pulse generation circuit includes: an oscillator and a pulse width modulation circuit; The oscillator is connected to the power supply through the pulse width modulation circuit. The power supply generates a trigger signal after passing through the pulse width modulation circuit. The trigger signal is received by the oscillator and generates a pulse signal. The power supply generates the pulse driving voltage under the control of the pulse signal; The trigger signal is a continuously changing voltage, and the value of the voltage at least includes less than 1 / 3 of the power supply voltage value and greater than 2 / 3 of the power supply voltage value.

3. The fuel cell according to claim 2, characterized in that, The oscillator is an NE555 timer, which includes pins 1 to 8. Among them, pin 1 is grounded, pins 4 and 8 are connected to the power supply, and pin 5 is floating; The pulse width modulation circuit includes a first resistor and a first capacitor connected in sequence to the positive pole of the power supply. One end of the first capacitor away from the positive pole of the power supply is grounded, and the node voltage between the first resistor and the first capacitor is the trigger signal; The trigger signal is respectively connected to the NE555 timer through pins 2 and 6 for logic processing, and then a corresponding pulse signal is output from pin 3 of the NE555 timer; The node between the first resistor and the first capacitor is also connected to pin 7 of the NE555 timer through a second resistor.

4. The fuel cell according to claim 1, characterized in that, The pulse generation circuit includes an oscillator and a pulse width modulation circuit. The pulse width modulation circuit enables the duty cycle of the pulse signal to be adjustable. When the solenoid valve is opened, the pulse signal has a first duty cycle. When the solenoid valve is kept open after being opened, the pulse signal has a second duty cycle, and the second duty cycle is less than the first duty cycle.

5. The fuel cell according to claim 3, characterized in that, The voltage value of the trigger signal is configured as: when the first capacitor starts to charge, its value is less than 1 / 3 of the power supply voltage; when the first capacitor discharges, its value is greater than 2 / 3 of the power supply voltage.

6. The fuel cell according to claim 3, characterized in that, The first resistor is an adjustable resistor, and it is provided with a switch for the user to adjust its resistance value.

7. The fuel cell according to claim 2, characterized in that, The pulse generation circuit further includes a switching tube, and the switching tube is connected in series with the coil. The discharge circuit includes at least one third diode connected in parallel with the coil, so that when the switching tube is turned off, the current in the coil discharges through the third diode.

8. The fuel cell according to claim 7, characterized in that, The pulse generation circuit further includes a third resistor and a fourth resistor connected in series. The third resistor is connected to the pulse signal, the fourth resistor is grounded, and the node between the third resistor and the fourth resistor is connected to the control pole of the switching tube.

9. The fuel cell according to claim 7, characterized in that, Within a period of the pulse signal, the turn-off time of the switching transistor is less than or equal to the time for the complete release of the energy of the coil inductance, such that the minimum current Im flowing through the coil during the turn-off time of the switching transistor is greater than 15% of the maximum current Id flowing through the coil when the switching transistor is turned on.

10. The fuel cell according to claim 3, characterized in that, A first diode is connected between the first resistor and the first capacitor, and the anode of the first diode is close to the positive electrode side of the power supply; The second resistor is connected to the cathode of the second diode, and the anode of the second diode is connected to the cathode of the first diode.

11. The fuel cell according to claim 3, characterized in that, The positive electrode of the power supply is grounded through a fifth resistor and a sixth resistor, and the node between the fifth resistor and the sixth resistor is connected to the first resistor.

Images