Oil tank switching valve control circuit with overcurrent and overload protection

Abstract

The utility model provides a kind of oil tank switching valve control circuit with overcurrent, overload protection function, and control circuit includes sliding switch K, resistance R1~R9, capacitor C1~C3, diode D1~D4, triode Q1, Q2, switch tube G1, G2, motor M;Sliding switch K includes static contact piece A, B, C;Motor M is connected electric brush P.The utility model control circuit has overcurrent and short-circuit protection function, if motor M short-circuit fault occurs, then switch tube G1 or G2 will immediately shut down, avoid circuit board burn and power supply line overheating fire.The utility model control circuit has overload protection function, if because of impurity jamming etc. during the conversion of switching valve, the working current of motor M is larger and cannot be completed conversion in certain time, then switch tube G1 or G2 is closed, avoid motor overheating burn.

Description

Technical Field

[0001] This utility model relates to a fuel tank switching valve control circuit, specifically a fuel tank switching valve control circuit with overcurrent and overload protection functions. Background Technology

[0002] The existing oil tank switching valve control circuit lacks overcurrent and overload protection circuits. When impurities get stuck in the valve core and prevent it from closing, excessive operating current is generated, which can burn out the motor and control circuit. Summary of the Invention

[0003] To solve the above-mentioned technical problems, this utility model provides a control circuit for a tank switching valve with overcurrent and overload protection functions. The control circuit has a simple structure, and the switching valve can be controlled to work in the main tank or auxiliary tank state by changing the power polarity of the two terminals; it can effectively realize the overcurrent and overload protection of the tank switching valve.

[0004] The technical solution adopted by this utility model is as follows:

[0005] A control circuit for a fuel tank switching valve with overcurrent and overload protection functions includes:

[0006] Slide switch K, resistors R1 to R9, capacitors C1 to C3, diodes D1 to D4, transistors Q1 and Q2, switching transistors G1 and G2, motor M;

[0007] The slide switch K includes stationary contacts A, B, and C; the brush P is linked to the motor M.

[0008] Terminal 1 is connected to one end of resistor R1, the emitter of transistor Q1, one end of capacitor C1, one end of resistor R5, one end of resistor R3, the anode of diode D3, and the source of switching transistor G1.

[0009] The other end of resistor R1 is connected to stationary contact A, and stationary contact B is connected to the anode of diode D1 and the anode of diode D2, respectively.

[0010] The cathode of diode D1 is connected to the collector of transistor Q1, the other end of resistor R3, the cathode of diode D3, and the gate of switching transistor G1; the base of transistor Q1 is connected to the other end of capacitor C1, the other end of resistor R5, and one end of resistor R6.

[0011] The other end of resistor R6 is connected to one end of resistor R9, the drain of VMOS transistor G1, and one end of motor M; the other end of resistor R9 is connected to one end of capacitor C3.

[0012] The stationary contact C is connected to one end of resistor R2. The anode of diode D2 is connected to the collector of transistor Q2, one end of resistor R4, the cathode of diode D4, and the gate of switching transistor G2.

[0013] The base of transistor Q2 is connected to one end of capacitor C2, one end of resistor R7, and one end of resistor R8; 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 switching transistor G2.

[0014] Terminal 2 is connected to the other end of resistor R2, the emitter of transistor Q2, the other end of capacitor C2, the other end of resistor R7, the other end of resistor R4, the anode of diode D4, and the source of switching transistor G2.

[0015] Both of the switching transistors G1 and G2 are VMOS transistors.

[0016] When terminal 1 and terminal 2 are connected to the switching valve, and terminal 1 is connected to the positive terminal of the power supply and terminal 2 is connected to the negative terminal, the switching valve operates in the main oil tank state.

[0017] When terminal 1 and terminal 2 are connected to the switching valve, and terminal 1 is connected to the negative terminal of the power supply and terminal 2 is connected to the positive terminal, the switching valve operates in the auxiliary oil tank state.

[0018] A method for controlling a fuel tank switching valve with overcurrent and overload protection: When terminal 1 is connected to the positive terminal of the battery, current I1 flows through resistor R1 → stationary contact A of sliding switch K → brush P → stationary contact B of sliding 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 switching transistor G2, causing switching transistor G2 to conduct, and then current I2 flows through the parasitic diode of switching transistor G1 → motor M → switching transistor G2 → to terminal 2, energizing motor M to rotate clockwise, while simultaneously driving brush P to move downwards.

[0019] When the brush P slides to the lower end of the slide switch K, the stationary contact A of the slide switch K is disconnected from the stationary contact B, and the stationary contact B is connected to the stationary contact C. At this time, the charge on the gate of the switching transistor G2 is discharged through the resistor R4, and the voltage drops (I3), causing the switching transistor G2 to turn off and the motor M to stop rotating. After the switching transistor G2 is turned off, the power supply voltage is applied to the base of the transistor Q2 through the resistor R8 (I4), making the transistor Q2 in the conducting state (I5), ensuring that the switching transistor G2 is reliably turned off.

[0020] The overload protection method for the fuel tank switching valve motor is as follows: When a short circuit fault occurs in the motor M, the short circuit current makes the Vds of the switching transistors G1 and G2 approximately equal to the power supply voltage. This voltage is applied to the base of the transistor Q2 (or Q1) through resistor R8 (or R6), causing the transistor Q2 (or Q1) to conduct. This causes the gate voltage of the switching transistor G2 (or G1) to drop rapidly to 0, and G2 (or G1) to turn off, cutting off the power supply to the motor M. The protection circuit components will not continue to be damaged, and the power supply line will not overheat due to the large current.

[0021] If impurities in the oil circuit increase the switching resistance of the switching valve, causing the operating current of the motor M to rise, the switching valve will control the timing of the protection action based on the overload current value and the overload time.

[0022] When terminal 1 is connected to the positive terminal of the power supply and terminal 2 is connected to the negative terminal of the power supply, the motor M rotates clockwise; if the polarity of the power supply is reversed, that is, when terminal 1 is connected to the negative terminal of the power supply and terminal 2 is connected to the positive terminal of the power supply, the motor M rotates counterclockwise.

[0023] The motor M is linked with the brush P, which is used to connect or disconnect the stationary contacts A, B, and C.

[0024] The stationary contact pieces A, B, and C are control electrodes.

[0025] If the switching valve is initially in the main oil tank position, brush P connects stationary contacts A and B. If the oil tank switching switch is pressed to switch the switching valve, the motor M rotates and drives brush P to connect stationary contacts A, B, and C. When brush P rotates to the state where it is disconnected from stationary contact A, the motor M stops rotating. At this time, brush P connects with stationary contacts B and C.

[0026] Control method of the switching valve after power failure and re-energization:

[0027] The operating position of the switching 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 terminal of the power supply and terminal 2 is connected to the negative terminal, the switching valve operates in the main oil tank state. When terminal 1 is connected to the negative terminal of the power supply and terminal 2 is connected to the positive terminal, the switching valve operates in the auxiliary oil tank state.

[0028] If the switching valve is switched to the correct position and then the power is cut off and then restored, as long as the state of the fuel tank switching switch remains unchanged, the switching valve will maintain the position it was in before the power was cut off.

[0029] If the state of the fuel tank selector switch is changed before power is applied, the selector valve will rotate to the fuel tank position corresponding to the fuel tank selector switch after power is applied.

[0030] If the switching valve loses power during the switching process, it will continue to rotate to the oil tank position corresponding to the oil tank selector switch after power is restored. In other words, the operating position of the switching valve is determined by the oil tank selector switch.

[0031] This utility model discloses a control circuit and control method for an oil tank switching valve with overcurrent and overload protection functions. The technical effects are as follows:

[0032] 1) The control circuit structure of this utility model is simple. By changing the power polarity of the two terminals, the switching valve can be controlled to work in the main oil tank or auxiliary oil tank state.

[0033] 2) The control circuit of this utility model has overcurrent and short circuit protection functions. If the motor M has a short circuit fault, the switching transistor G1 or G2 will be turned off immediately to avoid the circuit board burning out and the power line overheating and catching fire.

[0034] 3) The control circuit of this utility model has an overload protection function. If the working current of the motor M is large and cannot be completed within a certain time due to impurities or other reasons during the switching process, the switching tube G1 or G2 will be turned off to prevent the motor from overheating and burning out. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and examples;

[0036] Figure 1 This is the control circuit diagram for the oil tank switching valve of this utility model.

[0037] Figure 2 This is a schematic diagram showing the current flow direction of the motor M rotating clockwise in the oil tank switching valve of this utility model.

[0038] Figure 3 This is a schematic diagram showing the current flow direction during the shutdown process of the motor M of the oil tank switching valve of this utility model.

[0039] Figure 4 This is a schematic diagram of a rotary slide switch.

[0040] Figure 5 This is a diagram showing the relationship between the working oil tank and the electrode status.

[0041] Figure 6 This is a schematic diagram of a linear sliding switch.

[0042] Figure 7 Wiring diagram for the oil tank switching valve. Detailed Implementation

[0043] A fuel tank switching valve control circuit with overcurrent and overload protection functions, such as Figure 1 As shown, it includes:

[0044] Slide switch K, resistors R1 to R9, capacitors C1 to C3, diodes D1 to D4, transistors Q1 and Q2, switching transistors G1 and G2, motor M;

[0045] The slide switch K includes stationary contacts A, B, and C; the motor M is connected to the brush P;

[0046] Terminal 1 is connected to one end of resistor R1, the emitter of transistor Q1, one end of capacitor C1, one end of resistor R5, one end of resistor R3, the anode of diode D3, and the source of switching transistor G1.

[0047] The other end of resistor R1 is connected to stationary contact A, and stationary contact B is connected to the anode of diode D1 and the anode of diode D2, respectively.

[0048] The cathode of diode D1 is connected to the collector of transistor Q1, the other end of resistor R3, the cathode of diode D3, and the gate of switching transistor G1; the base of transistor Q1 is connected to the other end of capacitor C1, the other end of resistor R5, and one end of resistor R6.

[0049] The other end of resistor R6 is connected to one end of resistor R9, the drain of VMOS transistor G1, and one end of motor M; the other end of resistor R9 is connected to one end of capacitor C3.

[0050] The stationary contact C is connected to one end of resistor R2. The anode of diode D2 is connected to the collector of transistor Q2, one end of resistor R4, the cathode of diode D4, and the gate of switching transistor G2.

[0051] The base of transistor Q2 is connected to one end of capacitor C2, one end of resistor R7, and one end of resistor R8; 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 switching transistor G2.

[0052] Terminal 2 is connected to the other end of resistor R2, the emitter of transistor Q2, the other end of capacitor C2, the other end of resistor R7, the other end of resistor R4, the anode of diode D4, and the source of switching transistor G2.

[0053] Both of the switching transistors G1 and G2 are VMOS transistors.

[0054] A control method for an oil tank switching valve with overcurrent and overload protection functions, the basic working principle of which is as follows:

[0055] When terminal 1 is connected to the positive terminal of the battery, the current I1 flows through resistor R1 → stationary contact A of the slide switch K → brush P → stationary contact B of the 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 G2, causing switch G2 to conduct, and the current I2 flows through the parasitic diode of switch G1 → motor M → switch G2 → to terminal 2, as... Figure 2 As shown; when the motor M is energized, it rotates clockwise, simultaneously driving the brush P to move downwards. The function of resistor R9 and capacitor C3 is to absorb the electrical spark interference generated when the motor M rotates.

[0056] When brush P slides to the lower end of slide switch K, stationary contact A of slide switch K disconnects from stationary contact B, and stationary contact B connects with stationary contact C. At this time, the charge on the gate of switching transistor G2 is discharged through resistor R4, causing the voltage to drop (I3), which turns off switching transistor G2 and stops motor M from rotating. Figure 3As shown; after the switch G2 is turned off, the power supply voltage is applied to the base (I4) of the transistor Q2 through resistor R8, making the transistor Q2 conduct (I5), ensuring that the switch G2 is reliably turned off. The circuit remains stable in this state provided that the polarity of terminals 1 and 2 does not change.

[0057] The overload protection method for the fuel tank switching valve motor is as follows: The normal operating current of motor M is about 1A, and the on-resistance of G1 and G2 is about 0.6Ω. Under normal circumstances, the Vds of switching transistors G1 and G2 is ≤0.6V. When a short circuit fault occurs in motor M, the short circuit current makes the Vds of switching transistors G1 and G2 approximately equal to the power supply voltage. This voltage is applied to the base of transistor Q2 (or Q1) through resistor R8 (or R6), causing transistor Q2 (or Q1) to conduct. This causes the gate voltage of switching transistor G2 (or G1) to drop rapidly to 0, and G2 (or G1) to turn off, cutting off the power supply to motor M. The protection circuit components will not continue to be damaged, and the power supply line will not overheat due to the large current.

[0058] If impurities in the oil circuit increase the switching resistance of the switching valve, causing the operating current of the motor M to rise, the switching 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.

[0059] When terminal 1 is connected to the positive terminal of the power supply and terminal 2 is connected to the negative terminal of the power supply... Figure 1 When the lower half of the circuit is working, the motor M rotates clockwise; if the power supply polarity is reversed, i.e., terminal 1 is connected to the negative terminal and terminal 2 is connected to the positive terminal, then... Figure 1 When the upper part of the circuit is working, the motor M rotates counterclockwise.

[0060] like Figure 4 , Figure 7 As shown, stationary contacts A, B, and C are control electrodes. The motor M is linked to brush P, which is used to connect or disconnect stationary contacts A, B, and C. Normally, brush P connects stationary contacts A and B or stationary contacts B and C.

[0061] If the switching valve is initially in the main oil tank position, brush P connects stationary contacts A and B. If the oil tank switching switch is pressed to change the switching valve, the motor M rotates, causing brush P to connect stationary contacts A, B, and C. When brush P rotates to the point where it is disconnected from stationary contact A, the motor M stops rotating, and at this time, brush P connects to stationary 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 a diagram showing the relationship between the working oil tank and the electrode status.

[0062] The state of the switching valve after power failure and re-energization: Figure 7 Wiring diagram for a switching valve application.

[0063] The operating position of the switching 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 terminal of the power supply and terminal 2 is connected to the negative terminal, the switching valve operates in the main oil tank state. When terminal 1 is connected to the negative terminal of the power supply and terminal 2 is connected to the positive terminal, the switching valve operates in the auxiliary oil tank state.

[0064] If the switching valve is switched to the correct position and then the power is cut off and then restored, as long as the state of the fuel tank switching switch remains unchanged, the switching valve will maintain the position it was in before the power was cut off.

[0065] If the state of the fuel tank selector switch is changed before power is applied, the selector valve will rotate to the fuel tank position corresponding to the fuel tank selector switch after power is applied.

[0066] If the switching valve loses power during the switching process, it will continue to rotate to the oil tank position corresponding to the oil tank selector switch after power is restored. In other words, the operating position of the switching valve is determined by the oil tank selector switch.

Claims

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

2. The oil tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: Both of the switching transistors G1 and G2 are VMOS transistors.

3. The oil tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: The motor M is linked with the brush P.

4. The oil tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: The brush P is used to connect or disconnect the stationary contacts A, B, and C.

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

6. The oil tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: When terminal 1 and terminal 2 are connected to the switching valve, and terminal 1 is connected to the positive terminal of the power supply and terminal 2 is connected to the negative terminal, the switching valve operates in the main oil tank state.

7. The oil tank switching valve control circuit with overcurrent and overload protection functions according to claim 1, characterized in that: When terminal 1 and terminal 2 are connected to the switching valve, and terminal 1 is connected to the negative terminal of the power supply and terminal 2 is connected to the positive terminal, the switching valve operates in the auxiliary oil tank state.

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