An intelligent chassis electric control system of an automobile and a control circuit thereof

Abstract

This invention relates to solenoid valve fault diagnosis technology and discloses an automotive intelligent chassis electronic control system and its control circuit. The system includes a first fault diagnosis circuit and a second fault diagnosis circuit, each comprising a voltage acquisition unit, a voltage divider circuit, and a protection circuit. The protection circuit protects the fault diagnosis circuit, the voltage divider circuit divides the voltage output by the solenoid valve, and the voltage acquisition unit acquires the divided voltage. The voltage of the solenoid valve is acquired in real time using the voltage acquisition unit, and the state of the solenoid valve is determined based on the acquired voltage. This invention diagnoses faults in the solenoid valves of the automotive intelligent chassis electronic control system without requiring a driving solenoid valve. Each solenoid valve diagnosis requires only one port resource, making the diagnostic method simple and low-cost.

Description

Technical Field

[0001] This invention relates to electromagnetic valve fault diagnosis technology, and more particularly to an intelligent automotive chassis electronic control system and its control circuit. Background Technology

[0002] The electronically controlled dryer assembly with an ECU controller has protective functions, greatly extending the dryer's service life. Its main body contains an unloading solenoid valve and a backflush solenoid valve. Electrical malfunctions in the solenoid valves during use may affect the dryer's functionality.

[0003] For example, prior art 1: CN105549578B, an invention patent published on January 30, 2018, discloses a fault diagnosis and response circuit for automotive solenoid valves and its usage method, which includes a CPU, a solenoid valve, a logic operation processing circuit, an integrated chip and a display device. The logic operation processing circuit includes a NAND gate chip, a NOR gate chip and a comparator.

[0004] Existing technologies have complex circuits, high costs, and can only identify a fault in the solenoid valve, but cannot determine the specific type of fault.

[0005] The fault can only be detected after the solenoid valve is driven by the integrated chip BTS7236W, meaning the fault can only be detected when the solenoid valve is working. However, the solenoid valve is not working most of the time with the electronically controlled APU, resulting in poor timeliness of the existing technical solution.

[0006] Diagnosing each solenoid valve requires four port resources: an information output port, a main control signal output port, a secondary control signal output port, and a voltage input port. Diagnosing two solenoid valves requires eight port resources. The electronically controlled APU (Air Processing Unit), building upon the electronically controlled dryer, adds management of different air paths, achieving more precise and efficient air handling, significantly increasing the port resource requirements.

[0007] The electronically controlled APU primarily uses a 24V system, but a 12V system also exists. The solenoid valves used are correspondingly divided into two main categories: 24V solenoid valves and 12V solenoid valves. The resistance of a 24V solenoid valve is approximately 80Ω, while that of a 12V solenoid valve is approximately 20Ω. During installation, worker negligence may lead to mixing of different solenoid valves. Therefore, it is not possible to diagnose cases of mixed solenoid valve installations. Summary of the Invention

[0008] This invention addresses the problems of poor diagnostic timeliness and high port resource requirements of existing solenoid valves by providing an intelligent automotive chassis electronic control system and its control circuit.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0010] A control circuit for an automotive intelligent chassis electronic control system includes a first fault diagnosis circuit and a second fault diagnosis circuit. Both the first and second fault diagnosis circuits include a voltage acquisition unit, a voltage divider circuit, and a protection circuit. The protection circuit protects the fault diagnosis circuits. The voltage divider circuit divides the voltage output from the solenoid valve. The voltage acquisition unit acquires the divided voltage. The fault diagnosis method for the solenoid valve of the commercial vehicle electronic control APU includes:

[0011] The voltage of the solenoid valve is acquired in real time using the voltage acquisition device; the state of the solenoid valve is determined based on the acquired voltage.

[0012] Preferably, the states of the solenoid valve include the solenoid valve short-circuited to ground, the solenoid valve mixed installation state, the solenoid valve normal state, the solenoid valve open-circuit state, and the solenoid valve short-circuited to the power supply state.

[0013] Preferably, the first fault diagnosis circuit includes diode D1A, resistor R1A, diode D1B, resistor R1B, and voltage acquisition unit AD1.

[0014] The anode of diode D1A is connected to the input voltage U1; the cathode of diode D1A is connected to one end of resistor R1A, the other end of resistor R1A is connected to voltage acquisition device AD1 and the anode of diode D1B, the cathode of diode D1B is connected to resistor R1B and the output terminal OUT1 of solenoid valve, and the other end of resistor R1B is grounded.

[0015] The second fault diagnosis circuit includes diode D2A, resistor R2A, diode D2B, resistor R2B, and voltage acquisition unit AD2;

[0016] The anode of diode D2A is connected to the input voltage U2; the cathode of diode D2A is connected to one end of resistor R2A, the other end of resistor R2A is connected to voltage acquisition device AD2 and the anode of diode D2B, the cathode of diode D2B is connected to resistor R2B and the output terminal OUT2 of solenoid valve, and the other end of resistor R2B is grounded.

[0017] Preferably, when the resistance R1B is much greater than the resistance of the first solenoid valve, the voltage collected by the voltage collector AD1 is 0.5U1, and the state of the first solenoid valve is the normal state of the solenoid valve.

[0018] When the resistance R2B is much greater than the resistance of the second solenoid valve, the voltage collected by the voltage collector AD2 is 0.5U2, and the state of the second solenoid valve is the normal state of the solenoid valve.

[0019] Preferably, when the voltage collected by voltage collector AD1 is the voltage drop across diode D1B, the first solenoid valve is in a short-circuit state to ground; when the voltage collected by voltage collector AD2 is the voltage drop across diode D2B, the second solenoid valve is in a short-circuit state to ground.

[0020] Preferably, the voltage acquired by voltage acquisition device AD1 is U. D1B +R 1B *I 1b Among them, R 1B The resistance value of R1B is I. 1b The current flowing through it is U; therefore, the state of the first solenoid valve is the open-circuit state; the voltage collected by voltage collector AD2 is U. D2B +R 2B *I 2b Among them, R 2B The resistance value of R2B is I. 2b If the current flowing through it is , then the state of the second solenoid valve is the open-circuit state.

[0021] Preferably, the voltage acquired by voltage acquisition device AD1 is U1-U D1A -R 1A *I 1a Among them, R 1A Let I be the resistance value of R1A. 1a The current flowing through it is the current; therefore, the state of the first solenoid valve is that it is short-circuited to the power supply; the voltage collected by voltage collector AD2 is U2-U D2A -R 2A *I 2a Among them, R 2A The resistance value of R2A, I 2a If the current flowing through it is , then the state of the second solenoid valve is that the solenoid valve is short-circuited to the power supply.

[0022] Preferably, the voltage collected by voltage acquisition device AD1 is:

[0023] U 二极管 +(U1-2*U 二极管 )*R 电磁阀 / (R 1A +R 电磁阀 Then the state of the first solenoid valve is the state of mixed solenoid valve installation.

[0024] The voltage collected by voltage acquisition device AD2 is:

[0025] U 二极管 +(U2-2*U 二极管 )*R 电磁阀 / (R 2A +R电磁阀 If the state of the second solenoid valve is that the solenoid valves are mixed together, then the state of the second solenoid valve is that of the mixed solenoid valves.

[0026] To address the aforementioned technical problems, the present invention also provides a fault diagnosis device for a commercial vehicle electronically controlled APU solenoid valve, which is implemented using the aforementioned fault diagnosis method for a commercial vehicle electronically controlled APU solenoid valve.

[0027] This invention, by adopting the above technical solutions, has significant technical effects:

[0028] This invention can diagnose faults in the solenoid valves of the automotive intelligent chassis electronic control system without driving the solenoid valves. The diagnosis of each solenoid valve only requires one port resource, and the diagnosis method is simple and low-cost. Attached Figure Description

[0029] Figure 1 This is a circuit diagram of the present invention.

[0030] Figure 2 This is the diagnostic circuit diagram for the unloading solenoid valve of the present invention.

[0031] Figure 3 The diode 1N4007G of this invention has the characteristic curves of forward voltage drop and forward current at 25°C.

[0032] Figure 4 This is the equivalent circuit diagram of the open-circuit state of the solenoid valve of the present invention.

[0033] Figure 5 This is the equivalent circuit diagram of the solenoid valve of the present invention in relation to the power supply circuit state.

[0034] Figure 6 This is the logic control flowchart of the present invention. Detailed Implementation

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

[0036] Example 1

[0037] A control circuit for an automotive intelligent chassis electronic control system includes a first fault diagnosis circuit and a second fault diagnosis circuit. Both the first and second fault diagnosis circuits include a voltage acquisition unit, a voltage divider circuit, and a protection circuit. The protection circuit protects the fault diagnosis circuits. The voltage divider circuit divides the voltage output from the solenoid valve. The voltage acquisition unit acquires the divided voltage. The fault diagnosis method for the solenoid valve of the commercial vehicle electronic control APU includes:

[0038] The voltage of the solenoid valve is acquired in real time using the voltage acquisition device; the state of the solenoid valve is determined based on the acquired voltage.

[0039] The states of the solenoid valve include the solenoid valve short-circuited to ground, the solenoid valve mixed installation state, the solenoid valve normal state, the solenoid valve open-circuit state, and the solenoid valve short-circuited to the power supply state.

[0040] The first fault diagnosis circuit includes diode D1A, resistor R1A, diode D1B, resistor R1B, and voltage acquisition unit AD1; the anode of diode D1A is connected to the input voltage U1; the cathode of diode D1A is connected to the voltage acquisition unit AD1 and one end of resistor R1A, the other end of resistor R1A is connected to the anode of diode D1B, the cathode of diode D1B is connected to resistor R1B and the solenoid valve output terminal OUT1, and the other end of resistor R1B is grounded; the second fault diagnosis circuit includes diode D2A, resistor R2A, diode D2B, resistor R2B, and voltage acquisition unit AD2; the anode of diode D2A is connected to the input voltage U2; the cathode of diode D2A is connected to the voltage acquisition unit AD2 and one end of resistor R2A, the other end of resistor R2A is connected to the anode of diode D2B, the cathode of diode D2B is connected to resistor R2B and the solenoid valve output terminal OUT2, and the other end of resistor R2B is grounded.

[0041] When the resistance R1B is much greater than the resistance of the first solenoid valve, the voltage collected by the voltage collector AD1 is 0.5U1, and the state of the first solenoid valve is the normal state of the solenoid valve.

[0042] When the resistance R2B is much greater than the resistance of the second solenoid valve, the voltage collected by the voltage collector AD2 is 0.5U2, and the state of the second solenoid valve is the normal state of the solenoid valve.

[0043] When the voltage collected by voltage collector AD1 is the voltage drop across diode D1B, the first solenoid valve is in a short-circuit state to ground. When the voltage collected by voltage collector AD2 is the voltage drop across diode D2B, the second solenoid valve is in a short-circuit state to ground.

[0044] The voltage collected by voltage acquisition device AD1 is U D1B +R 1B *I 1b Among them, R 1B The resistance value of R1B is I. 1b The current flowing through it is U; therefore, the state of the first solenoid valve is the open-circuit state; the voltage collected by voltage collector AD2 is U. D2B +R 2B *I 2b Among them, R 2B The resistance value of R2B is I. 2bIf the current flowing through it is , then the state of the second solenoid valve is the open-circuit state.

[0045] The voltage collected by voltage acquisition device AD1 is U1-U D1A -R 1A *I 1a Among them, R 1A Let I be the resistance value of R1A. 1a The current flowing through it is the current; therefore, the state of the first solenoid valve is that it is short-circuited to the power supply; the voltage collected by voltage collector AD2 is U2-U D2A -R 2A *I 2a Among them, R 2A The resistance value of R2A, I 2a If the current flowing through it is , then the state of the second solenoid valve is that the solenoid valve is short-circuited to the power supply.

[0046] The voltage collected by voltage acquisition device AD1 is:

[0047] U 二极管 +(U1-2*U 二极管 )*R 电磁阀 / (R 1A +R 电磁阀 Then the state of the first solenoid valve is the state of mixed solenoid valve installation.

[0048] The voltage collected by voltage acquisition device AD2 is:

[0049] U 二极管 +(U2-2*U 二极管 )*R 电磁阀 / (R 2A +R 电磁阀 If the state of the second solenoid valve is that the solenoid valves are mixed together, then the state of the second solenoid valve is that of the mixed solenoid valves.

[0050] Example 2

[0051] Based on Example 1, this example is a fault diagnosis device for a commercial vehicle electronically controlled APU solenoid valve, which is implemented through the aforementioned fault diagnosis method for a commercial vehicle electronically controlled APU solenoid valve.

[0052] Example 3

[0053] Based on Example 1, Figure 1In the diagram, D1A is a voltage divider diode, primarily used for voltage division. Without this diode, the two fault states of an open circuit in the solenoid valve and a short circuit to the power supply cannot be distinguished by voltage. R1A's main function is voltage division; this resistor should be chosen with a value close to that of the solenoid valve. D1B is a reverse cutoff diode, primarily used to prevent the 24V voltage from directly affecting the MCU pins and burning out the MCU; it also serves a voltage divider function. R1B's main function is voltage division; without this resistor, the two fault states of an open circuit in the solenoid valve and a short circuit to the power supply cannot be distinguished by voltage, establishing a loop to ground when the solenoid valve is open. U9 is a high-side switch used to drive the solenoid valve, but it is not involved in solenoid valve diagnostics.

[0054] For solenoid valves used in electronically controlled APUs, sufficient power is required to drive them. A 24V solenoid valve has a resistance of approximately 80Ω and requires a voltage of ≥16V directly applied to it to drive it. A 12V solenoid valve has a resistance of approximately 20Ω and requires a voltage of ≥8V directly applied to it to actuate and control the air circuit.

[0055] The commercial electronically controlled APU system is a 24V system, and the diagnostic circuit of the unloading solenoid valve will be used as an example for explanation.

[0056] Figure 2 In this configuration, resistor R1A is 80Ω, resistor R1B is 20KΩ, and diodes D1A and D2A are both 1N4007G diodes. The MCU operates on a 5V power supply. The real-time voltage value acquired by the AD acquisition port AD1 is represented by the symbol Va.

[0057] Under normal solenoid valve conditions: R1B resistance > 200 times the unloading solenoid valve resistance. When calculating the parallel resistance of R1B and the unloading solenoid valve, it can be ignored. Thus, the AD1 to +5V circuit and the AD1 to ground circuit are symmetrical, and the voltage is equally distributed. Obviously, Va≈2.5V.

[0058] The solenoid valve is in a short-circuit state to ground, which means that the OUT1 port is short-circuited to ground. After the short circuit, the voltage of AD1 is the voltage drop of D1B. Figure 3 This is the characteristic curve of the forward voltage drop and forward current of diode 1N4007G at 25℃ (from the 1N4007G datasheet). When estimating the current Ia through D1B, the diode voltage drop is calculated as 0.7V, Ia≈(5-0.7-0.7) / 80=0.045A. Figure 3As can be seen, the diode voltage drop is approximately 0.7V at 0.045A. In practical applications, the above calculations are for reference only; the actual application requires testing to confirm the range of Va. Testing typically involves taking 3-6 samples and testing them in a temperature chamber at the operating temperature of the electronically controlled APU (-40℃ to +85℃). The results are then recorded, and the average voltage and estimated voltage range are calculated. When the solenoid valve is short-circuited to ground, Va≈0.7V.

[0059] In practical applications, the above calculations are for reference only. The actual application requires testing to confirm the range of Va. Testing typically involves taking 3-6 samples and testing them in a temperature chamber at the operating temperature of the electronically controlled APU (-40℃ to +85℃). The results are then recorded, and the average voltage and estimated voltage range are calculated. When the solenoid valve is short-circuited to ground, Va≈0.8V.

[0060] Figure 4 In the context of solenoid valve open / short circuit conditions: This means the connection between the OUT1 port and the solenoid valve is broken. The current Ia through D1B is in the μA range and cannot be obtained from... Figure 3 Estimate the voltage drop across D1A. In practical applications, the range of Va is confirmed through testing. Typically, 3-6 samples are taken and tested in a temperature chamber at the operating temperature of the electronically controlled APU (-40℃ to +85℃). The results are recorded, and then the average voltage and estimated voltage range are calculated. When the solenoid valve is short-circuited to the power supply, Va≈4.50V.

[0061] Figure 5 Solenoid valve short-circuit to power supply: A solenoid valve short-circuit to power supply means that the OUT1 port is short-circuited to the system power supply. When short-circuited, the negative terminal voltage of diode D1B is greater than the positive terminal voltage, diode D1B is reverse-biased and cut off, its equivalent resistance is in the MΩ range, and the current Ia through D1B is in the nA range, making it impossible to draw power from the source. Figure 3 Estimate the voltage drop across D1A. In practical applications, the range of Va is confirmed through testing. Typically, 3-6 samples are taken and tested in a temperature chamber at the operating temperature of the electronically controlled APU (-40℃ to +85℃). The results are recorded, and then the average voltage and estimated voltage range are calculated. When the solenoid valve is short-circuited to the power supply, Va≈4.85V.

[0062] The solenoid valve replacement status refers to the installation of a 20Ω 12V solenoid valve instead of an 80Ω 24V solenoid valve. The resistance of R1B is greater than 200 times the resistance of the unloading solenoid valve; therefore, the parallel resistance between R1B and the unloading solenoid valve can be ignored when calculating its value. Figure 3 This is the characteristic curve of the forward voltage drop and forward current of diode 1N4007G at 25℃ (from the 1N4007G datasheet). When estimating the current Ia through D1B, the diode voltage drop is calculated as 0.7V, Ia≈(5-0.7-0.7) / (80+20)=0.036A. Figure 3As can be seen, the diode voltage drop is approximately 0.7V at 0.036A. Va≈0.7+(5-0.7-0.7)*20 / (80+20)=1.42V.

[0063] The following control logic exists:

[0064] Table 1 Solenoid Valve Control Logic Table

[0065] Unloading solenoid valve status Va Control Logic Normal state 2.50V 2.35V≤Va≤2.65V, the unloading solenoid valve is in normal condition. short circuit to ground 0.7V 0.55V≤Va≤0.85V, the unloading solenoid valve is in a short-circuit state to ground. open circuit 4.50V 4.40V≤Va≤4.60V, the unloading solenoid valve is in the open circuit state. Short circuit of power supply 4.85V 4.70V≤Va≤4.95V, the unloading solenoid valve is in a short-circuit state to the power supply. Mixed state 1.42V 1.22V≤Va≤1.62V, unloading solenoid valves are in mixed configuration.

[0066] exist Figure 6 In the above calculations, the voltage range for a solenoid valve in its normal state is 2.35V≤Va≤2.65V; the voltage range for an unloading solenoid valve in its short-circuit state to ground is 0.55V≤Va≤0.85V; the voltage range for an unloading solenoid valve in its open-circuit state is 4.40V≤Va≤4.60V; the voltage range for an unloading solenoid valve in its short-circuit state to the power supply is 4.70V≤Va≤4.95V; and the voltage range for an unloading solenoid valve in its mixed-assembly state is 1.22V≤Va≤1.62V.

Claims

1. A control circuit for an intelligent automotive chassis electronic control system, characterized in that, The system includes a first fault diagnosis circuit and a second fault diagnosis circuit. Both circuits include a voltage acquisition unit, a voltage divider circuit, and a protection circuit. The protection circuit protects the fault diagnosis circuit. The voltage divider circuit divides the voltage output by the solenoid valve. The voltage acquisition unit acquires the divided voltage. The voltage of the solenoid valve is acquired in real time. The state of the solenoid valve is determined based on the acquired voltage. The states of the solenoid valve include: short-circuited to ground, mixed-installation, normal operation, open circuit, and short-circuited to power supply. The first fault diagnosis circuit includes diode D1A, resistor R1A, diode D1B, resistor R1B, and voltage acquisition unit AD1. The anode of diode D1A is connected to the input voltage U1; the cathode of diode D1A is connected to one end of resistor R1A, the other end of resistor R1A is connected to voltage acquisition device AD1 and the anode of diode D1B, the cathode of diode D1B is connected to resistor R1B and the output terminal OUT1 of solenoid valve, and the other end of resistor R1B is grounded. The second fault diagnosis circuit includes diode D2A, resistor R2A, diode D2B, resistor R2B, and voltage acquisition unit AD2; The anode of diode D2A is connected to the input voltage U2; the cathode of diode D2A is connected to one end of resistor R2A, the other end of resistor R2A is connected to voltage acquisition device AD2 and the anode of diode D2B, the cathode of diode D2B is connected to resistor R2B and the output terminal OUT2 of solenoid valve, and the other end of resistor R2B is grounded.

2. The control circuit of an intelligent automotive chassis electronic control system according to claim 1, characterized in that, When the resistance R1B is much greater than the resistance of the first solenoid valve, the voltage collected by the voltage collector AD1 is 0.5U1, and the state of the first solenoid valve is the normal state of the solenoid valve. When the resistance R2B is much greater than the resistance of the second solenoid valve, the voltage collected by the voltage collector AD2 is 0.5U2, and the state of the second solenoid valve is the normal state of the solenoid valve.

3. The control circuit of an intelligent automotive chassis electronic control system according to claim 1, characterized in that, When the voltage collected by voltage collector AD1 is the voltage drop across diode D1B, the first solenoid valve is in a short-circuit state to ground. When the voltage collected by voltage collector AD2 is the voltage drop across diode D2B, the second solenoid valve is in a short-circuit state to ground.

4. The control circuit of an intelligent automotive chassis electronic control system according to claim 1, characterized in that, The voltage collected by voltage acquisition device AD1 is U D1B +R 1B *I 1b Among them, R 1B The resistance value of R1B is I. 1b The current flowing through it is U; therefore, the state of the first solenoid valve is the open-circuit state; the voltage collected by voltage collector AD2 is U. D2B +R 2B *I 2b Among them, R 2B The resistance value of R2B is I. 2b If the current flowing through it is , then the state of the second solenoid valve is the open-circuit state.

5. The control circuit of an intelligent automotive chassis electronic control system according to claim 1, characterized in that, The voltage collected by voltage acquisition device AD1 is U1-U D1A -R 1A *I 1a ; Among them, R 1A Let I be the resistance value of R1A. 1a The current flowing through it is the current; therefore, the state of the first solenoid valve is that it is short-circuited to the power supply; the voltage collected by voltage collector AD2 is U2-U D2A -R 2A *I 2a Among them, R 2A The resistance value of R2A, I 2a If the current flowing through it is , then the state of the second solenoid valve is that the solenoid valve is short-circuited to the power supply.

6. The control circuit of an intelligent automotive chassis electronic control system according to claim 1, characterized in that, The voltage collected by voltage acquisition device AD1 is: U 二极管 +(U1-2*U 二极管 )*R 电磁阀 / (R) 1A +R 电磁阀 Then the state of the first solenoid valve is the mixed solenoid valve state; The voltage collected by voltage acquisition device AD2 is: U 二极管 +(U2-2*U 二极管 )*R 电磁阀 / (R) 2A +R 电磁阀 Then the state of the second solenoid valve is the state of mixed solenoid valve installation.

7. An intelligent automotive chassis electronic control system, characterized in that, The control circuit of an intelligent chassis electronic control system for automobiles as described in any one of claims 1-6 is included.

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