Oil tank change-over valve control circuit with overcurrent and overload protection functions and control method

Abstract

The invention discloses an oil tank change-over valve control circuit with overcurrent and overload protection functions and a control method. The control circuit comprises a slide switch K, resistors R1 to R9, capacitors C1 to C3, diodes D1 to D4, triodes Q1 and Q2, switch tubes G1 and G2 and a motor M, the slide switch K comprises static contact sheets A, B and C; the motor M is connected with the brush P. The control circuit has overcurrent and short-circuit protection functions, if a short-circuit fault occurs to the motor M, the switching tube G1 or G2 can be turned off immediately, and burnout of a circuit board and fire caused by overheating of a power line are avoided. The control circuit has an overload protection function, if the working current of the motor M is large and conversion cannot be completed within a certain time due to impurity clamping stagnation and the like in the conversion process of the conversion valve, the switching tube G1 or G2 is closed, and the motor is prevented from being overheated and burnt.

Description

Technical Field

[0001] The present invention relates to a fuel tank conversion valve control circuit, and in particular to a fuel tank conversion valve control circuit with overcurrent and overload protection functions and a control method. Background Art

[0002] The existing fuel tank switching valve control circuit is not designed with overcurrent and overload protection circuits. When impurities are stuck in the valve core and the valve core cannot be closed, excessive operating current will be generated, causing the motor and control circuit to burn out. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a fuel tank conversion valve control circuit and control method with overcurrent and overload protection functions. The control circuit has a simple structure. By changing the power polarity of the two terminal terminals, the conversion valve can be controlled to operate in the main fuel tank or auxiliary fuel tank state; it can effectively realize the overcurrent and overload protection of the fuel tank conversion valve.

[0004] The technical solution adopted by the present invention is: A fuel tank switching valve control circuit with overcurrent and overload protection functions, comprising: Slide switch K, resistors R1~R9, capacitors C1~C3, diodes D1~D4, transistors Q1, Q2, switches G1, G2, motor M; The sliding switch K includes static contact pieces A, B, and C; the brush P is linked to the motor M; Terminal 1 is respectively connected to one end of the resistor R1, the emitter of the transistor Q1, one end of the capacitor C1, one end of the resistor R5, one end of the resistor R3, the anode of the diode D3, and the source of the switch tube G1; The other end of the resistor R1 is connected to the static contact piece A, and the static contact piece B is connected to the anode of the diode D1 and the anode of the diode D2 respectively; The cathode of the diode D1 is connected to the collector of the transistor Q1, the other end of the resistor R3, the cathode of the diode D3, and the gate of the switch tube G1; the base of the transistor Q1 is connected to the other end of the capacitor C1, the other end of the resistor R5, and one end of the resistor R6. The other end of the resistor R6 is connected to one end of the resistor R9, the drain of the VMOS tube G1, and one end of the motor M respectively; the other end of the resistor R9 is connected to one end of the capacitor C3; The static contact piece C is connected to one end of the resistor R2, and the anode of the diode D2 is connected to the collector of the transistor Q2, one end of the resistor R4, the cathode of the diode D4, and the gate of the switch tube G2 respectively; The base of transistor Q2 is connected to one end of capacitor C2, one end of resistor R7, and one end of resistor R8 respectively; the other end of resistor R8 is connected to the other end of capacitor C3, the other end of motor M, and the drain of switch tube G2 respectively; The terminal 2 is respectively connected to the other end of the resistor R2, the emitter of the transistor Q2, the other end of the capacitor C2, the other end of the resistor R7, the other end of the resistor R4, the anode of the diode D4, and the source of the switch tube G2.

[0005] The switch tubes G1 and G2 are both VMOS tubes.

[0006] A fuel tank transfer valve control method with overcurrent and overload protection functions. When terminal 1 is connected to the positive terminal of a battery, current I1 flows through resistor R1, static contact A of slide switch K, brush P, static contact B of slide switch K, diode D2, resistor R4, terminal 2, and finally to the negative terminal of the battery. The voltage drop across resistor R4 is applied to the gate of switch G2, turning it on. Current I2 then flows through the parasitic diode of switch G1, motor M, switch G2, and finally to terminal 2. Energized, motor M rotates clockwise, simultaneously driving brush P downward.

[0007] When the brush P slides to the lower end of the slide switch K, the static contact piece A and the static contact piece B of the slide switch K are disconnected, and the static contact piece B and the static contact piece C are connected. At this time, the charge on the gate of the switch tube G2 is discharged through the resistor R4, and the voltage decreases (I3), turning off the switch tube G2 and stopping the rotation of the motor M. After the switch tube G2 is turned off, the power supply voltage is applied to the base of the transistor Q2 through the resistor R8 (I4), turning on the transistor Q2 (I5), ensuring that the switch tube G2 is reliably turned off.

[0008] The fuel tank switching valve motor overload protection method is as follows: when a short-circuit fault occurs in the motor M, the short-circuit current makes the Vds of the switching tubes G1 and G2 approximately equal to the power supply voltage. This voltage is applied to the base of the transistor Q2 (or Q1) through the resistor R8 (or R6), causing the transistor Q2 (or Q1) to turn on, causing the gate voltage of the switching tube G2 (or G1) to drop rapidly to 0, and G2 (or G1) to turn off and cut off the power supply to the motor M, protecting the circuit components from further damage and the power supply line from overheating due to the large current.

[0009] If impurities in the oil circuit increase the switching resistance of the switching valve and increase the operating current of the motor M, the switching valve will control the protection action time according to the overload current value and overload time; When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole of the power supply, the motor M rotates clockwise; if the polarity of the power supply is reversed, that is, terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole of the power supply, the motor M rotates counterclockwise.

[0010] The motor M is linked to a brush P, which is used to connect or disconnect the static contact pieces A, B, and C.

[0011] The static contact pieces A, B, and C are control electrodes.

[0012] If the conversion valve is in the main oil tank position in the initial state, the brush P connects the static contacts A and B. If the oil tank conversion switch is pressed to switch the conversion valve, the motor M rotates and drives the brush P to connect the static contacts A, B, and C. When the brush P rotates to the state of being disconnected from the static contact A, the motor M stops rotating. At this time, the brush P is connected to the static contacts B and C.

[0013] Control method of switching valve after power failure: The working position of the conversion valve is determined by the polarity of the power supply connected to terminal 1 and terminal 2. When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole, the conversion valve works in the main fuel tank state. When terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole, the conversion valve works in the auxiliary fuel tank state.

[0014] If the power is turned off and then on again after the conversion valve is switched to the right position, as long as the fuel tank conversion switch state remains unchanged, the conversion valve will maintain the position state before the power is turned off; If the fuel tank transfer switch status is changed before power is applied, the transfer valve will rotate to the fuel tank position corresponding to the fuel tank transfer switch after power is applied again; If the power is cut off during the switching process, the switching valve will continue to rotate to the fuel tank position corresponding to the fuel tank switch after the power is restored. In other words, the working state position of the switching valve is determined by the fuel tank switch.

[0015] The present invention provides a fuel tank switching valve control circuit and control method with overcurrent and overload protection functions, and the technical effects are as follows: 1) The control circuit structure of the present invention is simple, and the switching valve can be controlled to operate in the main tank or auxiliary tank state by changing the power polarity of the two terminals.

[0016] 2) The control circuit of the present invention has overcurrent and short-circuit protection functions. If a short-circuit fault occurs in the motor M, the switch tube G1 or G2 will be turned off immediately to prevent the circuit board from burning out and the power circuit from overheating and fire.

[0017] 3) The control circuit of the present invention has an overload protection function. If the operating current of the motor M is large and the conversion cannot be completed within a certain period of time due to impurities stuck in the conversion valve during the conversion process, the switch tube G1 or G2 is closed to prevent the motor from overheating and burning. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and examples; Figure 1 This is the control circuit diagram of the fuel tank conversion valve of the present invention.

[0019] Figure 2 Schematic diagram of the current flow when the motor M of the fuel tank switching valve of the present invention rotates clockwise.

[0020] Figure 3 Schematic diagram of current flow during the shut-off process of the motor M of the fuel tank switching valve of the present invention.

[0021] Figure 4 Schematic diagram of a rotary slide switch.

[0022] Figure 5 This is the relationship diagram between the working oil tank and the electrode status.

[0023] Figure 6 Schematic diagram of a linear sliding switch.

[0024] Figure 7 Tank changeover valve application wiring diagram. DETAILED DESCRIPTION

[0025] A fuel tank switching valve control circuit with overcurrent and overload protection functions, such as Figure 1 As shown, including: Slide switch K, resistors R1~R9, capacitors C1~C3, diodes D1~D4, transistors Q1, Q2, switches G1, G2, motor M; The sliding switch K includes static contacts A, B, and C; the motor M is connected to the brush P; Terminal 1 is respectively connected to one end of the resistor R1, the emitter of the transistor Q1, one end of the capacitor C1, one end of the resistor R5, one end of the resistor R3, the anode of the diode D3, and the source of the switch tube G1; The other end of the resistor R1 is connected to the static contact piece A, and the static contact piece B is connected to the anode of the diode D1 and the anode of the diode D2 respectively; The cathode of the diode D1 is connected to the collector of the transistor Q1, the other end of the resistor R3, the cathode of the diode D3, and the gate of the switch tube G1; the base of the transistor Q1 is connected to the other end of the capacitor C1, the other end of the resistor R5, and one end of the resistor R6. The other end of the resistor R6 is connected to one end of the resistor R9, the drain of the VMOS tube G1, and one end of the motor M respectively; the other end of the resistor R9 is connected to one end of the capacitor C3; The static contact piece C is connected to one end of the resistor R2, and the anode of the diode D2 is connected to the collector of the transistor Q2, one end of the resistor R4, the cathode of the diode D4, and the gate of the switch tube G2 respectively; The base of transistor Q2 is connected to one end of capacitor C2, one end of resistor R7, and one end of resistor R8 respectively; the other end of resistor R8 is connected to the other end of capacitor C3, the other end of motor M, and the drain of switch tube G2 respectively; The terminal 2 is respectively connected to the other end of the resistor R2, the emitter of the transistor Q2, the other end of the capacitor C2, the other end of the resistor R7, the other end of the resistor R4, the anode of the diode D4, and the source of the switch tube G2.

[0026] The switch tubes G1 and G2 are both VMOS tubes.

[0027] A fuel tank switching valve control method with overcurrent and overload protection functions. The basic working principle is as follows: When terminal 1 is connected to the positive terminal of the battery, current I1 flows through resistor R1 → fixed contact A of slide switch K → brush P → fixed contact B of slide switch K → diode D2 → resistor R4 → terminal 2 → to the negative terminal of the battery; the voltage drop across resistor R4 is applied to the gate of switch tube G2, turning on switch tube G2. Then current I2 flows through the parasitic diode of switch tube G1 → motor M → switch tube G2 → to terminal 2, as shown in the following figure: Figure 2 As shown in the figure, the motor M rotates clockwise when it is energized, and at the same time drives the brush P downward. The function of the resistor R9 and capacitor C3 is to absorb the spark interference generated by the rotation of the motor M.

[0028] When the brush P slides to the lower end of the slide switch K, the static contact piece A and the static contact piece B of the slide switch K are disconnected, and the static contact piece B and the static contact piece C are connected. At this time, the charge on the gate of the switch tube G2 is discharged through the resistor R4 and the voltage is reduced (I3), so that the switch tube G2 is turned off and the motor M stops rotating. Figure 3 As shown in the figure, after switch G2 is turned off, the power supply voltage is applied to the base of transistor Q2 (I4) through resistor R8, turning transistor Q2 on (I5), ensuring reliable shutoff of switch G2. The circuit remains stable in this state as long as the polarity of terminals 1 and 2 remains unchanged.

[0029] The fuel tank switching valve motor overload protection method is as follows: the normal operating current of the motor M is about 1A, the on-resistance of G1 and G2 is about 0.6Ω, and under normal circumstances, the Vds of the switching tubes G1 and G2 is ≤ 0.6V. When a short-circuit fault occurs in the motor M, the short-circuit current makes the Vds of the switching tubes G1 and G2 approximately equal to the power supply voltage. This voltage is applied to the base of the transistor Q2 (or Q1) through the resistor R8 (or R6), turning on the transistor Q2 (or Q1), causing the gate voltage of the switching tube G2 (or G1) to drop rapidly to 0. G2 (or G1) is turned off, cutting off the power supply to the motor M, protecting the circuit components from further damage and the power supply line from overheating due to the large current.

[0030] If impurities in the oil circuit increase the switching resistance of the conversion valve and increase the operating current of the motor M, the conversion valve will control the protection action time according to the overload current value and overload time; when the overload current is 6A, the protection action time is 20ms.

[0031] When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole of the power supply, Figure 1The lower half of the circuit works, and the motor M rotates clockwise; if the power supply polarity is reversed, that is, terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole of the power supply, then Figure 1 The upper half of the circuit works and the motor M rotates counterclockwise.

[0032] like Figure 4 、 Figure 7 As shown, the static contacts A, B, and C are control electrodes. The motor M is linked to the brush P, which is used to connect or disconnect the static contacts A, B, and C. Normally, the brush P connects the static contacts A and B or the static contacts B and C. If the switching valve is initially in the main tank position, the brush P connects the static contacts A and B. If the tank switch is pressed to switch the switching valve, the motor M rotates and drives the brush P to connect the static contacts A, B, and C. When the brush P rotates to a state where it is disconnected from the static contact A, the motor M stops rotating, and the brush P connects the static contacts B and C. The arc length of the rotary slide switch electrode determines the working angle of the motor M. Figure 5 This is the relationship diagram between the working oil tank and the electrode status.

[0033] After power off and then on again, the status of the conversion valve is: Figure 7 Apply the wiring schematic to the diverter valve.

[0034] The working position of the conversion valve is determined by the polarity of the power supply connected to terminal 1 and terminal 2. When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole, the conversion valve works in the main fuel tank state. When terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole, the conversion valve works in the auxiliary fuel tank state.

[0035] If the power is turned off and then on again after the conversion valve is switched to the right position, as long as the fuel tank conversion switch state remains unchanged, the conversion valve will maintain the position state before the power is turned off; If the fuel tank transfer switch status is changed before power is applied, the transfer valve will rotate to the fuel tank position corresponding to the fuel tank transfer switch after power is applied again; If the power is cut off during the switching process, the switching valve will continue to rotate to the fuel tank position corresponding to the fuel tank switch after the power is restored. In other words, the working state position of the switching valve is determined by the fuel tank switch.

Claims

1. A fuel tank switching valve control circuit with overcurrent and overload protection functions, characterized in that: include: Slide switch K, resistors R1~R9, capacitors C1~C3, diodes D1~D4, transistors Q1, Q2, switches G1, G2, motor M; The sliding switch K includes static contact pieces A, B, and C; the brush P is linked to the motor M; Terminal 1 is respectively connected to one end of the resistor R1, the emitter of the transistor Q1, one end of the capacitor C1, one end of the resistor R5, one end of the resistor R3, the anode of the diode D3, and the source of the switch tube G1; The other end of the resistor R1 is connected to the static contact piece A, and the static contact piece B is connected to the anode of the diode D1 and the anode of the diode D2 respectively; The cathode of the diode D1 is connected to the collector of the transistor Q1, the other end of the resistor R3, the cathode of the diode D3, and the gate of the switch tube G1; the base of the transistor Q1 is connected to the other end of the capacitor C1, the other end of the resistor R5, and one end of the resistor R6. The other end of the resistor R6 is connected to one end of the resistor R9, the drain of the VMOS tube G1, and one end of the motor M respectively; the other end of the resistor R9 is connected to one end of the capacitor C3; The static contact piece C is connected to one end of the resistor R2, and the anode of the diode D2 is connected to the collector of the transistor Q2, one end of the resistor R4, the cathode of the diode D4, and the gate of the switch tube G2 respectively; The base of transistor Q2 is connected to one end of capacitor C2, one end of resistor R7, and one end of resistor R8 respectively; the other end of resistor R8 is connected to the other end of capacitor C3, the other end of motor M, and the drain of switch tube G2 respectively; The terminal 2 is respectively connected to the other end of the resistor R2, the emitter of the transistor Q2, the other end of the capacitor C2, the other end of the resistor R7, the other end of the resistor R4, the anode of the diode D4, and the source of the switch tube G2.

2. The fuel tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: The switch tubes G1 and G2 are both VMOS tubes.

3. The fuel tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: The motor M is linked to a brush P, which is used to connect or disconnect the static contact pieces A, B, and C.

4. The fuel tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: The static contact pieces A, B, and C are control electrodes.

5. A method for controlling a fuel tank switching valve with overcurrent and overload protection functions using a control circuit according to any one of claims 1 to 4, characterized in that: When terminal 1 is connected to the positive terminal of the battery, current I1 flows through resistor R1, static contact A of slide switch K, brush P, static contact B of slide switch K, diode D2, resistor R4, terminal 2, and finally to the negative terminal of the battery. The voltage drop across resistor R4 is applied to the gate of switch G2, turning it on. Current I2 then flows through the parasitic diode of switch G1, motor M, switch G2, and finally to terminal 2. Motor M rotates clockwise, driving brush P downward. When the brush P slides to the lower end of the slide switch K, the static contact piece A and the static contact piece B of the slide switch K are disconnected, and the static contact piece B and the static contact piece C are connected. At this time, the charge on the gate of the switch tube G2 is discharged through the resistor R4, and the voltage is reduced, so that the switch tube G2 is turned off and the motor M stops rotating. After the switch tube G2 is turned off, the power supply voltage is applied to the base of the transistor Q2 through the resistor R8, so that the transistor Q2 is in the on state, ensuring that the switch tube G2 is reliably turned off.

6. A method for protecting a fuel tank switching valve motor from overload using a control circuit according to any one of claims 1 to 4, characterized in that: When a short-circuit fault occurs in the motor M, the short-circuit current makes the Vds of the switching tubes G1 and G2 approximately equal to the power supply voltage. This voltage is applied to the base of the transistor Q2 through the resistor R8, turning on the transistor Q2, causing the gate voltage of the switching tube G2 to drop rapidly to 0. G2 is turned off and the power supply to the motor M is cut off, protecting the circuit components from further damage and the power supply line from overheating due to the large current.

7. The fuel tank switching valve motor overload protection method according to claim 6, characterized in that: If impurities in the oil circuit increase the switching resistance of the switching valve and increase the operating current of the motor M, the switching valve will control the timing of the protection action according to the overload current value and the overload time.

8. The fuel tank switching valve motor overload protection method according to claim 6, characterized in that: When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole of the power supply, the motor M rotates clockwise; if the polarity of the power supply is reversed, that is, terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole of the power supply, the motor M rotates counterclockwise.

9. The fuel tank switching valve motor overload protection method according to claim 6, characterized in that: If the conversion valve is in the main oil tank position in the initial state, the brush P connects the static contacts A and B. If the oil tank conversion switch is pressed to switch the conversion valve, the motor M rotates and drives the brush P to connect the static contacts A, B, and C. When the brush P rotates to the state of being disconnected from the static contact A, the motor M stops rotating. At this time, the brush P is connected to the static contacts B and C.

10. A method for controlling a switching valve after power failure and power on again using a control circuit according to any one of claims 1 to 4, characterized in that: The working position of the conversion valve is determined by the polarity of the power supply connected to terminal 1 and terminal 2. When terminal 1 is connected to the positive pole of the power supply and terminal 2 is connected to the negative pole, the conversion valve works in the main fuel tank state. When terminal 1 is connected to the negative pole of the power supply and terminal 2 is connected to the positive pole, the conversion valve works in the auxiliary fuel tank state. If the power is turned off and then on again after the conversion valve is switched to the right position, as long as the fuel tank conversion switch state remains unchanged, the conversion valve will maintain the position state before the power is turned off; If the fuel tank transfer switch status is changed before power is applied, the transfer valve will rotate to the fuel tank position corresponding to the fuel tank transfer switch after power is applied again; If the conversion valve loses power during the switching process, the conversion valve will continue to rotate to the fuel tank position corresponding to the fuel tank conversion switch after power is restored; that is, the working state position of the conversion valve is determined by the fuel tank conversion switch.

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