A circuit and method for detecting a failure of an electromagnetic coil of a brake system cut valve

Abstract

The application provides a circuit and method for detecting the fault of the electromagnetic coil of the cut-off valve of a brake system. The application connects a relay U2 and a sampling resistor R in series between the negative end of the electromagnetic coil of the cut-off valve and the ground wire, and connects a first amplification circuit to the negative end of the electromagnetic coil of the cut-off valve. The two ends of the sampling resistor R are connected with a second amplification circuit. Through the first and second amplification circuits, the voltage of the electromagnetic coil of the cut-off valve can be detected, and the current flowing through the electromagnetic coil of the cut-off valve can also be detected. The method collects the voltage of the electromagnetic coil of the cut-off valve and the current flowing through the electromagnetic coil of the cut-off valve through the first and second amplification circuits, sets multiple rated values according to the resistance value of the electromagnetic coil of the cut-off valve and the sampling resistor R and the power supply voltage of the electromagnetic coil of the cut-off valve, and can detect the fault in the open valve and closed valve states. The open circuit fault and short circuit fault mode of the electromagnetic coil of the cut-off valve can be detected, and the safety of the brake system is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of wheel brake control technology, specifically relating to a circuit and method for detecting faults in the solenoid coil of the brake system cut-off valve. Background Technology

[0002] The aircraft brake control system is a component of the aircraft takeoff and landing system. It is mainly used to shorten the landing roll distance, control the ground taxiing direction, and ensure the safe braking and stopping of the aircraft under abnormal conditions such as aborting takeoff.

[0003] With the significant increase in aircraft weight and landing speed, the kinetic energy and landing distance during landing increase dramatically, leading to the widespread adoption of more powerful hydraulic braking systems. Currently, most mainstream aircraft wheel brake control systems employ fly-by-wire (FOB) systems, which combine electronic control and hydraulic pressure. In an FOB system, the brake controller uses electrical signals to control the opening and closing of a shut-off valve, thus connecting and disconnecting the pressure source for the braking system. Simultaneously, it calculates the appropriate braking amount based on braking commands and controls the servo valve to adjust the braking pressure. Therefore, the shut-off valve is not only a key component of the brake control system but also a "safety switch" for the wheel brake system, ensuring safe landing and takeoff by controlling the flow of hydraulic fluid.

[0004] The shut-off valve in the electric brake control system is an electrically controlled electromagnetic shut-off valve. The electrically controlled electromagnetic shut-off valve consists of an electromagnetic coil, a valve core, a spring, and a hydraulic passage. When energized, the electromagnetic coil generates magnetic force to attract the valve core, compress the spring, open the oil circuit, and allow hydraulic pressure to flow to the brake device. When de-energized, the electromagnetic coil loses power, the spring resets, and pushes the valve core to close the oil circuit, cutting off the hydraulic supply. Therefore, the state of the shut-off valve's electromagnetic coil is directly related to the state of the shut-off valve. From the perspective of fault mode analysis, the fault modes of the electromagnetic coil include coil short circuit and open circuit.

[0005] Existing single-relay fault detection methods can only detect faults when the shut-off valve is closed, and can only detect open-circuit faults in the shut-off valve's solenoid coil, but cannot detect short-circuit faults. Figure 1 As shown, when the relay is off, the negative terminal of the shut-off valve's solenoid coil is not grounded, so the voltage at the negative terminal should be the power supply voltage. If the coil is open-circuited at this time, there will be no voltage at the negative terminal, thus indicating an open-circuit fault. However, if the coil is short-circuited, the voltage at the negative terminal will be no different from when the relay is on or off, making it impossible to determine the fault. When the relay is on, the voltage at the negative terminal is the same as under normal conditions regardless of the fault state, so it is also impossible to detect the fault state of the shut-off valve when the valve is open.

[0006] This leads to insufficient fault diagnosis on the shut-off valve side. If there is a short circuit fault in the shut-off valve solenoid coil and the fault detection fails to detect it, the shut-off valve may fail to open during braking, resulting in brake failure. It may also cause the shut-off valve to fail to close when it is open, leaving safety hazards such as excessive brake pressure or residual brake pressure. Excessive brake pressure and residual brake pressure are the main causes of tire blowouts. Summary of the Invention

[0007] To address the technical problem in the prior art that the open-circuit and short-circuit fault modes of the shut-off valve solenoid coil cannot be detected in both open and closed valve states, this application provides a circuit and method for detecting faults in the shut-off valve solenoid coil of a brake system.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, this application provides a circuit for detecting a fault in the solenoid coil of a brake system cut-off valve, including a cut-off valve solenoid coil, and a relay U2 and a sampling resistor R connected in series between the negative terminal of the cut-off valve solenoid coil and the ground wire. The negative terminal of the cut-off valve solenoid coil is also connected to a first amplification circuit, and the two ends of the sampling resistor R are connected to a second amplification circuit.

[0010] The first amplifier circuit includes an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected to one end of resistors R11 and R12. The other end of resistor R11 is connected to the negative terminal of the solenoid coil of the shut-off valve, and the other end of resistor R12 is grounded. The inverting input terminal of the operational amplifier U1A is connected to one end of resistors R13 and R14. The other end of resistor R13 is grounded, and the other end of resistor R14 is connected to the output terminal of the operational amplifier U1A.

[0011] The second amplifier circuit includes an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to one end of resistors R21 and R22. The other end of resistor R21 is connected between relay U2 and sampling resistor R. The other end of resistor R22 is grounded. The inverting input terminal of the operational amplifier U1B is connected to one end of resistors R23 and R24. The other end of resistor R23 is connected to ground. The other end of resistor R24 ​​is connected to the output terminal of the operational amplifier U1B.

[0012] In a second aspect, this application provides a method for detecting a fault in the solenoid coil of a brake system shut-off valve, comprising the following steps:

[0013] When the brake control software outputs a low control signal for the shut-off valve, the relay U2 is turned on, current flows through the shut-off valve solenoid coil and the sampling resistor R, the shut-off valve opens, and the second actual detection signal of the sampling resistor R is collected by the second amplifier circuit. If the second actual detection signal is the preset first rated value, the shut-off valve solenoid coil is normal; if the second actual detection signal is greater than the preset second rated value, the shut-off valve solenoid coil is short-circuited.

[0014] When the brake control software outputs a high control signal for the shut-off valve, the relay U2 is disconnected, the shut-off valve is closed, and the first actual detection signal at the negative terminal of the shut-off valve solenoid coil is acquired through the first amplifier circuit. If the first actual detection signal is the third rated value, the shut-off valve solenoid coil is normal; if the first actual detection signal is less than the preset fourth rated value, the shut-off valve solenoid coil is open-circuit faulted.

[0015] Furthermore, the second actual detection signal is the amplified voltage value of the actual voltage of the sampling resistor R after passing through the preset amplification factor of the second amplification circuit, and the first actual detection signal is the amplified voltage value of the actual voltage of the shut-off valve solenoid coil after passing through the preset amplification factor of the first amplification circuit.

[0016] Furthermore, the preset amplification factor of the second amplifier circuit is 10 times, and the preset amplification factor of the first amplifier circuit is 4 times.

[0017] Furthermore, if the actual resistance of the shut-off valve solenoid coil is less than 50% of its rated resistance, it is considered a short circuit fault; if the actual resistance of the shut-off valve solenoid coil is greater than 1.9 times its rated resistance, it is considered an open circuit fault.

[0018] Furthermore, based on the power supply voltage across the solenoid coil of the shut-off valve, as well as the rated resistance of the solenoid coil and the resistance of the sampling resistor R, the rated voltages of the solenoid coil and the sampling resistor R under normal conditions are calculated respectively.

[0019] The product of the rated voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit is used as the first rated value;

[0020] The product of the rated voltage of the shut-off valve solenoid coil and the preset amplification factor of the first amplifier circuit is used as the third rated value.

[0021] Furthermore, in the event of a short circuit fault, assuming that the actual resistance of the shut-off valve solenoid coil is 50% of the rated resistance of the shut-off valve solenoid coil, the actual voltage of the sampling resistor R is calculated based on the power supply voltage across the shut-off valve solenoid coil and the resistance of the sampling resistor R. In the event of a short circuit fault, the product of the actual voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit will be used as the second rated value.

[0022] In the case of an open-circuit fault, considering signal noise and detection error, the fourth rating is 1V.

[0023] Furthermore, it also includes:

[0024] When the shut-off valve is open, the voltage at the positive terminal of the shut-off valve solenoid coil and the voltage at the negative terminal of the shut-off valve solenoid coil are detected simultaneously, and the real-time voltage drop UL on the shut-off valve solenoid coil is calculated. The second actual detection signal of the sampling resistor R is acquired through the second amplification circuit to obtain the real-time current IL of the shut-off valve solenoid coil.

[0025] Based on the real-time voltage drop UL and real-time current IL of the shut-off valve solenoid coil, the real-time impedance of the shut-off valve solenoid coil is obtained.

[0026] A first impedance threshold and a second impedance threshold are preset. If the real-time impedance is less than the first impedance threshold or greater than the second impedance threshold, the solenoid coil of the shut-off valve is determined to be faulty.

[0027] Furthermore, the voltage at the negative terminal of the shut-off valve solenoid coil is the ratio of the first actual detected signal to the amplification factor of the first amplification circuit.

[0028] When the real-time current IL is obtained, the real-time voltage of the sampling resistor R is obtained based on the ratio of the second actual detection signal to the amplification factor of the second amplifier circuit, and the real-time current IL is obtained based on the ratio of the real-time voltage of the sampling resistor R to the resistance value of the sampling resistor R.

[0029] Furthermore, the first impedance threshold is 20Ω, and the second impedance threshold is 100Ω.

[0030] Compared with the prior art, the present invention has the following beneficial technical effects:

[0031] This application provides a circuit and method for detecting faults in the solenoid coil of a brake system cut-off valve. The application connects a relay U2 and a sampling resistor R in series between the negative terminal of the solenoid coil and ground. A first amplification circuit is connected to the negative terminal of the solenoid coil, and a second amplification circuit is connected across the sampling resistor R. Through the first and second amplification circuits, not only the voltage of the solenoid coil but also the current flowing through it can be detected. This method acquires the voltage and current of the solenoid coil through the first and second amplification circuits. Based on the resistance values ​​of the solenoid coil and the sampling resistor R, as well as the power supply voltage of the solenoid coil, multiple rated values ​​are set. Fault detection can be performed in both open and closed valve states. It can detect open-circuit and short-circuit faults in the solenoid coil, effectively improving the adequacy of fault detection and enhancing the safety of the brake system. Attached Figure Description

[0032] Figure 1 A schematic diagram of a shut-off valve fault detection circuit in the prior art is shown;

[0033] Figure 2 A circuit diagram for detecting a fault in the solenoid coil of a brake system shut-off valve is shown in an embodiment of this disclosure.

[0034] Figure 3 A circuit diagram illustrating a fault detection circuit for the solenoid coil of a brake system shut-off valve is shown in an embodiment of this disclosure. Detailed Implementation

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] Figure 2 and Figure 3 A circuit diagram for detecting a fault in the solenoid coil of a brake system shut-off valve, according to an embodiment of this disclosure, is shown. Figure 2 and Figure 3 As shown, it includes a shut-off valve solenoid coil, and a relay U2 and a sampling resistor R connected in series between the negative terminal of the shut-off valve solenoid coil and the ground wire. The negative terminal of the shut-off valve solenoid coil is also connected to a first amplifier circuit, and the two ends of the sampling resistor R are connected to a second amplifier circuit.

[0037] The first amplifier circuit includes an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected to one end of resistors R11 and R12. The other end of resistor R11 is connected to the negative terminal of the solenoid coil of the shut-off valve, and the other end of resistor R12 is grounded. The inverting input terminal of the operational amplifier U1A is connected to one end of resistors R13 and R14. The other end of resistor R13 is grounded, and the other end of resistor R14 is connected to the output terminal of the operational amplifier U1A.

[0038] The second amplifier circuit includes an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to one end of resistors R21 and R22. The other end of resistor R21 is connected between relay U2 and sampling resistor R. The other end of resistor R22 is grounded. The inverting input terminal of the operational amplifier U1B is connected to one end of resistors R23 and R24. The other end of resistor R23 is connected to ground. The other end of resistor R24 ​​is connected to the output terminal of the operational amplifier U1B.

[0039] It should be noted that, taking the first amplifier circuit as an example, resistor R12 forms part of the voltage divider network, and resistor R11 forms the other part of the voltage divider network, providing the input signal for operational amplifier U1A to achieve input voltage adaptation / filtering. One end of resistor R13 is grounded, and the other end is connected to the inverting input terminal of operational amplifier U1A, providing a reference potential for the op-amp. Resistor R14 connects the output terminal and the inverting input terminal of operational amplifier U1A, forming a negative feedback loop that determines the voltage gain of the circuit.

[0040] This disclosure also provides a method for detecting a fault in the solenoid coil of a brake system shut-off valve, comprising the following steps:

[0041] When the brake control software outputs a low control signal for the shut-off valve, the relay U2 is turned on, current flows through the shut-off valve solenoid coil and the sampling resistor R, the shut-off valve opens, and the second actual detection signal of the sampling resistor R is collected by the second amplifier circuit. If the second actual detection signal is the preset first rated value, the shut-off valve solenoid coil is normal; if the second actual detection signal is greater than the preset second rated value, the shut-off valve solenoid coil is short-circuited.

[0042] When the brake control software outputs a high control signal for the shut-off valve, the relay U2 is disconnected, the shut-off valve is closed, and the first actual detection signal at the negative terminal of the shut-off valve solenoid coil is acquired through the first amplifier circuit. If the first actual detection signal is the third rated value, the shut-off valve solenoid coil is normal; if the first actual detection signal is less than the preset fourth rated value, the shut-off valve solenoid coil is open-circuit faulted.

[0043] Specifically, the fault modes and detection control of the shut-off valve solenoid coil are shown in Table 1. The sampling resistor value is very small, and when the coil is normal, the voltage drop across the sampling resistor is approximately zero.

[0044] Table 1

[0045]

[0046] As shown in Table 1, when relay U2 is turned on, the solenoid coil of the shut-off valve is energized, and the shut-off valve opens. If the solenoid coil of the shut-off valve is normal, the voltage at the positive and negative terminals of the solenoid coil is normal, and current flows through the solenoid coil. As can be seen from Table 1, if the solenoid coil of the shut-off valve is short-circuited at this time, the current flowing through the sampling resistor R is very large, resulting in a significant increase in the voltage drop across the sampling resistor R. Therefore, when the shut-off valve is open, the short circuit of the solenoid coil of the shut-off valve can be detected by detecting the voltage drop across the sampling resistor R.

[0047] When relay U2 is disconnected, the solenoid coil of the shut-off valve is not energized, and the shut-off valve is closed. If the solenoid coil of the shut-off valve is functioning normally, the voltage at both the positive and negative terminals of the solenoid coil is the power supply voltage, and no current flows through the solenoid coil. As shown in Table 1, if the solenoid coil of the shut-off valve is in an open-circuit state at this time, the voltage at the negative terminal of the solenoid coil is 0. Therefore, when the shut-off valve is closed, the open-circuit status of the solenoid coil can be detected by detecting the voltage at the negative terminal of the solenoid coil.

[0048] In this embodiment, the second actual detection signal is the amplified voltage value of the actual voltage of the sampling resistor R after passing through the preset amplification factor of the second amplification circuit, and the first actual detection signal is the amplified voltage value of the actual voltage of the shut-off valve solenoid coil after passing through the preset amplification factor of the first amplification circuit; specifically, in this embodiment, the preset amplification factor of the second amplification circuit is 10 times, and the preset amplification factor of the first amplification circuit is 4 times.

[0049] In this embodiment, if the actual resistance of the shut-off valve solenoid coil is less than 50% of its rated resistance, it is considered a short circuit fault; if the actual resistance is greater than 1.9 times its rated resistance, it is considered an open circuit fault. Specifically, in this embodiment, the shut-off valve solenoid coil is connected to a 24V power supply. Assuming the rated operating current range when the shut-off valve is open is 500mA, the rated resistance of the shut-off valve solenoid coil is 50Ω, and the sampling resistor R is 1Ω, if the actual resistance of the shut-off valve solenoid coil is less than 25Ω, it is a short circuit; if the actual resistance is greater than 95Ω, it is an open circuit.

[0050] In this embodiment, based on the power supply voltage across the solenoid coil of the shut-off valve, as well as the rated resistance of the solenoid coil and the resistance of the sampling resistor R, the rated voltages of the solenoid coil and the sampling resistor R under normal conditions are calculated respectively.

[0051] The product of the rated voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit is used as the first rated value;

[0052] The product of the rated voltage of the shut-off valve solenoid coil and the preset amplification factor of the first amplifier circuit is used as the third rated value.

[0053] Furthermore, in the event of a short circuit fault, assuming that the actual resistance of the shut-off valve solenoid coil is 50% of the rated resistance of the shut-off valve solenoid coil, the actual voltage of the sampling resistor R is calculated based on the power supply voltage across the shut-off valve solenoid coil and the resistance of the sampling resistor R. In the event of a short circuit fault, the product of the actual voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit will be used as the second rated value.

[0054] In the case of an open-circuit fault, considering signal noise and detection error, the fourth rating is 1V.

[0055] In this embodiment, detecting whether the solenoid coil of the shut-off valve is short-circuited by detecting the voltage drop across the sampling resistor R includes:

[0056] When the shut-off valve is open, the voltage at the positive terminal of the shut-off valve solenoid coil and the voltage at the negative terminal of the shut-off valve solenoid coil are detected simultaneously, and the real-time voltage drop UL on the shut-off valve solenoid coil is calculated. The second actual detection signal of the sampling resistor R is acquired through the second amplification circuit to obtain the real-time current IL of the shut-off valve solenoid coil.

[0057] Based on the real-time voltage drop UL and real-time current IL of the shut-off valve solenoid coil, the real-time impedance of the shut-off valve solenoid coil is obtained.

[0058] A first impedance threshold and a second impedance threshold are preset. If the real-time impedance is less than the first impedance threshold or greater than the second impedance threshold, the solenoid coil of the shut-off valve is determined to be faulty.

[0059] Furthermore, the voltage at the negative terminal of the shut-off valve solenoid coil is the ratio of the first actual detected signal to the amplification factor of the first amplification circuit.

[0060] When the real-time current IL is obtained, the real-time voltage of the sampling resistor R is obtained based on the ratio of the second actual detection signal to the amplification factor of the second amplifier circuit. The real-time current IL is obtained based on the ratio of the real-time voltage of the sampling resistor R to the resistance value of the sampling resistor R. Specifically, the first impedance threshold is 20Ω, and the second impedance threshold is 100Ω.

[0061] This embodiment proposes a method for an aircraft wheel braking system that not only detects the coil voltage but also the current flowing through the coil. It can detect two fault modes of the shut-off valve coil, namely open circuit and short circuit, in both open and closed valve states. It can also measure the impedance of the shut-off valve coil.

Claims

1. A circuit for detecting a fault in the solenoid coil of a brake system shut-off valve, characterized in that, It includes a shut-off valve solenoid coil, and a relay U2 and a sampling resistor R connected in series between the negative terminal of the shut-off valve solenoid coil and the ground wire. The negative terminal of the shut-off valve solenoid coil is also connected to a first amplifier circuit, and the two ends of the sampling resistor R are connected to a second amplifier circuit. The first amplifier circuit includes an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected to one end of resistors R11 and R12. The other end of resistor R11 is connected to the negative terminal of the solenoid coil of the shut-off valve, and the other end of resistor R12 is grounded. The inverting input terminal of the operational amplifier U1A is connected to one end of resistors R13 and R14. The other end of resistor R13 is grounded, and the other end of resistor R14 is connected to the output terminal of the operational amplifier U1A. The second amplifier circuit includes an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to one end of resistors R21 and R22. The other end of resistor R21 is connected between relay U2 and sampling resistor R. The other end of resistor R22 is grounded. The inverting input terminal of the operational amplifier U1B is connected to one end of resistors R23 and R24. The other end of resistor R23 is connected to ground. The other end of resistor R24 ​​is connected to the output terminal of the operational amplifier U1B.

2. A method for detecting a fault in the solenoid coil of a brake system shut-off valve, characterized in that, The circuit for detecting a fault in the solenoid coil of a brake system shut-off valve, as described in claim 1, includes the following steps: When the brake control software outputs a low control signal for the shut-off valve, the relay U2 is turned on, current flows through the shut-off valve solenoid coil and the sampling resistor R, the shut-off valve opens, and the second actual detection signal of the sampling resistor R is collected by the second amplifier circuit. If the second actual detection signal is the preset first rated value, the shut-off valve solenoid coil is normal; if the second actual detection signal is greater than the preset second rated value, the shut-off valve solenoid coil is short-circuited. When the brake control software outputs a high control signal for the shut-off valve, the relay U2 is disconnected, the shut-off valve is closed, and the first actual detection signal at the negative terminal of the shut-off valve solenoid coil is acquired through the first amplifier circuit. If the first actual detection signal is the third rated value, the shut-off valve solenoid coil is normal; if the first actual detection signal is less than the preset fourth rated value, the shut-off valve solenoid coil is open-circuit faulted.

3. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 2, characterized in that, The second actual detection signal is the amplified voltage value of the actual voltage of the sampling resistor R after passing through the preset amplification factor of the second amplification circuit, and the first actual detection signal is the amplified voltage value of the actual voltage of the shut-off valve solenoid coil after passing through the preset amplification factor of the first amplification circuit.

4. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 3, characterized in that, The preset amplification factor of the second amplifier circuit is 10 times, and the preset amplification factor of the first amplifier circuit is 4 times.

5. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 3, characterized in that, If the actual resistance of the shut-off valve solenoid coil is less than 50% of its rated resistance, it is considered a short circuit fault. If the actual resistance of the shut-off valve solenoid coil is greater than 1.9 times its rated resistance, it is considered an open circuit fault.

6. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 5, characterized in that, Based on the power supply voltage across the solenoid coil of the shut-off valve, as well as the rated resistance of the solenoid coil and the resistance of the sampling resistor R, calculate the rated voltage of the solenoid coil and the sampling resistor R under normal conditions. The product of the rated voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit is used as the first rated value; The product of the rated voltage of the shut-off valve solenoid coil and the preset amplification factor of the first amplifier circuit is used as the third rated value.

7. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 6, characterized in that, In the event of a short circuit fault, assuming that the actual resistance of the shut-off valve solenoid coil is 50% of the rated resistance of the shut-off valve solenoid coil, the actual voltage of the sampling resistor R is calculated based on the power supply voltage across the shut-off valve solenoid coil and the resistance of the sampling resistor R. The product of the actual voltage of the sampling resistor R and the preset amplification factor of the second amplifier circuit will be used as the second rated value in the event of a short circuit fault. In the case of an open-circuit fault, considering signal noise and detection error, the fourth rating is 1V.

8. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 2, characterized in that, Also includes: When the shut-off valve is open, the voltage at the positive terminal of the shut-off valve solenoid coil and the voltage at the negative terminal of the shut-off valve solenoid coil are detected simultaneously, and the real-time voltage drop UL on the shut-off valve solenoid coil is calculated. The second actual detection signal of the sampling resistor R is acquired through the second amplification circuit to obtain the real-time current IL of the shut-off valve solenoid coil. Based on the real-time voltage drop UL and real-time current IL of the shut-off valve solenoid coil, the real-time impedance of the shut-off valve solenoid coil is obtained. A first impedance threshold and a second impedance threshold are preset. If the real-time impedance is less than the first impedance threshold or greater than the second impedance threshold, the solenoid coil of the shut-off valve is determined to be faulty.

9. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 8, characterized in that, The voltage at the negative terminal of the solenoid coil of the shut-off valve is the ratio of the first actual detected signal to the amplification factor of the first amplifier circuit. When the real-time current IL is obtained, the real-time voltage of the sampling resistor R is obtained based on the ratio of the second actual detection signal to the amplification factor of the second amplifier circuit, and the real-time current IL is obtained based on the ratio of the real-time voltage of the sampling resistor R to the resistance value of the sampling resistor R.

10. The method for detecting a fault in the solenoid coil of a brake system shut-off valve according to claim 8, characterized in that, The first impedance threshold is 20Ω, and the second impedance threshold is 100Ω.

Images