JP3150001B2 - Fail-safe method for anti-skid device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid device for an automobile (hereinafter referred to as an ABS device), and more particularly to a fail-safe method when a short circuit occurs between the positive side of a power supply and the ground side of a solenoid valve circuit. is there.

[0002]

2. Description of the Related Art Conventionally, an ABS device for a vehicle is provided in the middle of a flow path for transmitting a brake pressure in a master cylinder operated by a brake pedal to a wheel cylinder of each wheel. When approaching, the solenoid valve alternately reduces and increases the brake pressure to prevent the wheels from skidding.
It can maintain stable running performance.

[0003] The ABS device is provided with a main relay that functions to turn on an alarm lamp, turn off a solenoid valve, and return to a normal braking function when an abnormality occurs in the system. by the way,
A short test pulse is applied to the solenoid valve drive circuit to deal with the case where the drive current supply line to the solenoid valve is broken or the switching element for controlling the solenoid valve is faulty, and the state change is monitored. Japanese Patent Laid-Open No. Sho 62-17 discloses a method of detecting a failure in a drive circuit of a solenoid valve by logically checking.
It is proposed in Japanese Patent No. 3366.

[0004]

When the malfunction of the solenoid valve circuit is detected as described above, the ABS controller prohibits the ABS control as usual and turns off the main relay. However, if the cause of the failure is that the earth side of the solenoid valve circuit is short-circuited to the power supply + pole, turning off the main relay will apply a reverse voltage to the solenoid valve, adversely affecting the solenoid valve. There is a possibility that it will. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fail-safe method for an ABS device that does not adversely affect a solenoid valve when a short circuit occurs between a power supply and a positive pole of the solenoid valve circuit.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a solenoid valve for controlling wheel brake pressure, and a power supply side of the solenoid valve connected to a power supply.
Detects the main relay that is turned on and off to switch to the ground and the voltage on the ground side of the solenoid valve
In anti-skid apparatus having a detection means, the
Turn on the main relay and turn on the power supply side of the solenoid valve.
Connected to the power supply and the solenoid valve at that time.
A first detection step of detecting an abnormality in the solenoid valve circuit based on a voltage change on the ground side, and when the abnormality is detected in the first detection step, the main relay is turned off.
Grounding the power supply side of the solenoid valve by grounding, and connecting the ground side of the solenoid valve when the main relay is OFF .
The method includes a second detecting step of detecting an abnormality of the solenoid valve circuit by a voltage change , and a step of turning on a main relay when an abnormality is detected again in the second detecting step.

[0006]

In the first stage, first, an abnormality in the solenoid valve circuit is detected. As a detection method, the main relay is set to O
N, the power supply side of the solenoid valve is connected to the power supply, and the voltage change on the ground side at that time may be monitored. If the solenoid valve circuit is normal, the voltage on the earth side is reduced at the same time as the main relay is turned on. On the other hand, if there is an abnormality, the voltage does not decrease. If an abnormality is detected in the first detection step, the cause of the abnormality is the grounding of the solenoid valve .
It is not possible to determine whether the side has caused a short-circuit fault in the power supply + pole or another fault (for example, an internal fault in the controller). Therefore, first turn the main relay off.
F, the power supply side of the solenoid valve is grounded, and it is detected again whether there is an abnormality in the solenoid valve circuit. In this case as well, the change in voltage on the earth side of the solenoid valve may be monitored. If the main relay is turned off and the voltage on the ground side drops, it is not at least a short-circuit failure, but if the voltage remains high, it is a short-circuit failure. Here, if it is determined that a short circuit has occurred, the main relay is turned on, and the power supply side of the solenoid valve is connected to the power supply + pole. Thus, no reverse voltage is applied to the solenoid valve, and the solenoid valve is not adversely affected.

[0007]

FIG. 1 is a system diagram of a vehicle ABS apparatus according to the present invention. In the figure, reference numeral 1 denotes an ABS controller which controls the system and controls each unit. Reference numeral 2 denotes an on-vehicle battery, 3 denotes a brake switch that is turned on in response to operation of a brake pedal, and 4 denotes a brake lamp that notifies an operation state of the brake pedal. Lights up. The battery 2, the brake switch 3, the brake lamp 4, and the wiring connecting them constitute a brake lamp circuit. The ON / OFF signal of the brake switch 3 is transmitted to the controller 1
Input of the terminal T _1. Reference numerals 5, 6, 7, and 8 denote wheel speed sensors that independently detect the wheel speeds of the four wheels, and detection signals from these sensors 5 to 8 are input to the controller 1, respectively.

Reference numeral 10 denotes a pump motor, which drives a pump for pumping the brake fluid of the reservoir to the dynamic pressure side. A normally open contact 11 a of a motor relay 11 is connected in series with the pump motor 10, and a signal of the pump motor 10 is input to a terminal T _{2 of the} controller 1. The coil 11b of the motor relay 11 is controlled by the terminal T ₃ of the controller 1.

Reference numeral 12 denotes an ignition switch which is a main power switch, and a signal of the ignition switch 12 is input to a terminal T _{4 of the} controller 1. The ignition switch 12 is connected in series with the alarm lamp 13, and further via a diode 14.
5 are connected in series to the contact 15a. Main relay 15
Functions to turn on the alarm lamp 13 when a failure occurs in the ABS system, and to turn off solenoid valves 20 to 23 to be described later to return to a normal braking function. The alarm lamp 13 is also connected to the terminal T _{5 of the} controller 1, and the alarm lamp 13 can be turned on independently of the main relay 15 by grounding the terminal T ₅ . Power supply side coil 15b of the main relay 15 is connected to an ignition switch 12, the ground side is connected to the terminal T _6. Then, the controller 1 is energized to the coil 15b by grounding the terminal T _6, switched contact 15a is to the left in FIG. 1 (ON state), the warning lamp 13 is turned off. When the coil 15b is not energized, the contact 15a is grounded (OFF state), and the alarm lamp 13 is turned on.

The coil 1 of the motor relay 11 is provided between the diode 14 and the contact 15a of the main relay 15.
1b and the power supply side of the solenoid valves 20 to 23. The solenoid valves 20 to 23 are valves for decreasing or increasing the brake pressure. Although only four solenoid valves are shown in FIG. 1, actually two solenoid valves are provided for each wheel, for a total of eight solenoid valves. Downstream sides (ground side) of the solenoid valves 20 to 23 are connected to the controller 1 respectively. When the main relay 15 is turned off, the motor relay 1
1 and the solenoid valves 20 to 23 are also turned off, and only when the main relay 15 is turned on, the motor relay 11 and the solenoid valves 20 to 23 are also in an operable state.

FIG. 2 shows the details of the connection between the solenoid valve 20 and the controller 1. In the figure, reference numeral 24 denotes a central processing unit (CP) constituting a main part of the controller 1.
U) and 25 are transistors constituting a solenoid drive circuit. The collector of the transistor 25 is connected to the solenoid valve 20 and the terminal 24a of the CPU 24, and the emitter is grounded. The base is connected to a terminal 24b of the CPU 24. CP connected to collector
A terminal 24a of U24 is a terminal for monitoring a terminal voltage of the solenoid valve 20, and a terminal 24b connected to the base is a terminal for driving a transistor. Note that the other solenoid valves 21 to 23 and the controller 1
Is also the same as described above, and a description thereof will be omitted.

Here, a fail-safe method when the power supply short-circuit of the solenoid valves 20 to 23, that is, when the earth side of the solenoid valve 20 is short-circuited to the power supply + electrode side will be described. First, the main relay 15 is turned on with the ignition switch 12 turned on, and then the transistor 25 is turned on. As a result, the current flows to the ground via the contact 15a, the solenoid valves 20 to 23, and the transistor 25, and the solenoid valves 20 to 2
3 is driven. At this time, if the collector voltage (voltage of the terminal 24a) is at L level, the solenoid valve circuit is normal, but if it is at H level, there is some failure.
By this failure detection, the controller 1 operates normally
As well as prohibiting the S control, turns on the alarm lamp 13 through a terminal T _5, after shutting OFF the transistor 25 turns OFF the main relay 15, turns on the alarm lamp 13.
That is, the power supply side of the solenoid valves 20 to 23 is the contact 1
It will be grounded via 5a. However, the cause of the failure of the solenoid valve circuit is the solenoid valves 20 to 2
3, when the power supply on the ground side is short-circuited, a reverse voltage is applied to the solenoids 20 to 23 when the main relay 15 is turned off.
May be adversely affected. Therefore, in the present invention, when the failure of the solenoid valve circuit is detected, the transistor 25 is turned off, and then the main relay 15 is once turned off. At this stage, the failure of the solenoid valve circuit is detected again. This is because it cannot be determined whether the main relay 15 is in the ON state because of a short-circuit failure of the solenoid valves 20 to 23 or an internal failure of the controller 1 (a disconnection failure of the transistor 25). if,
If the collector voltage drops to the L level when the main relay 15 is turned off, it is not at least a short-circuit failure of the solenoid valve, but if the collector voltage is maintained at the H level, it is a short-circuit failure. Here, if it is determined that a short circuit has occurred, the main relay 15 is turned on, and the power supply side of the solenoid valves 20 to 23 is connected to the power supply + pole. As a result, no reverse voltage is applied to the solenoid valves 20 to 23, so that the solenoid valves 20 to 23 are not adversely affected.

Next, the fail-safe method will be described with reference to FIG. First, the ignition switch 12
Is turned on to start the control, and after performing system initial processing (S ₁ ) such as memory check and initial value setting, the main relay 15 is set to ON (S
₂ ). Subsequently, the process proceeds to the ABS system control process. In the system control process, the solenoid valves 20 to 23 is turned ON first (S _3), determines whether the solenoid valve terminal voltage is at H level (S _4). If it is at L level, the solenoid valve circuit is not broken and the process ends.
And, if H level, because there is some failure, the terminal T ₅ turns on the alarm lamp 13 (S _5), after shutting OFF the solenoid valves 20 to 23 (S _6), turns OFF the main relay 15 ( S _7). Then, it is determined again whether the solenoid valve terminal voltage is at the H level (S ₈ ). If it is at H level, it is a short-circuit failure.
Because the main relay 15 is turned ON again (S _9), so as not to apply a reverse voltage to the solenoid valve 20-23. On the other hand, if the solenoid valve terminal voltage is at the L level, it is a failure other than a short-circuit failure, and the process ends . Although not shown in FIG. 3, since the main relay 15 is turned on after the determination of the short-circuit failure, the failure detection of the excitation circuit, the solenoid valve circuit, the motor relay circuit, etc. of the main relay 15 is continued during that time. You may go.

[0014]

As is apparent from the above description, according to the present invention, when the abnormality of the solenoid valve circuit is detected in the first detection step, first, the main relay is turned off, and then the abnormality of the solenoid valve circuit is performed again. The main relay is turned ON when a fault is detected.
It is possible to reliably determine whether or not the cause is a short-circuit failure of the power supply and the positive electrode on the ground side of the solenoid valve, and no reverse voltage is applied to the solenoid valve, so that the solenoid valve is not adversely affected.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an ABS device for implementing a fail-safe method of the present invention.

FIG. 2 is a detailed circuit diagram of a main part of FIG.

FIG. 3 is a flowchart illustrating a fail-safe method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ABS controller 2 Battery 5-8 Wheel speed sensor 10 Pump motor 11 Motor relay 12 Ignition switch 13 Alarm lamp 15 Main relay 15b Coil 20-23 Solenoid valve 24 CPU 25 Transistor

Claims (1)

(57) [Claims] 1. A solenoid valve for controlling wheel brake pressure, and a power supply side of the solenoid valve is grounded to a power supply.
The main relay, which is turned on and off to switch connection to the switch, and the detection for detecting the voltage on the earth side of the solenoid valve
In anti-skid and means exit, the power supply side of the solenoid valve is turned ON the main relay
And the solenoid valve at that time
A first detection step of detecting an abnormality in the solenoid valve circuit based on a voltage change on the ground side of the solenoid valve. If an abnormality is detected in the first detection step, the main relay is turned off to turn off the power supply of the solenoid valve
Grounding step and grounding side of solenoid valve when main relay is OFF
A second detection step of detecting an abnormality of the solenoid valve circuit by a voltage change of the solenoid valve, and a step of turning on a main relay when the abnormality is detected again in the second detection step. Safe way.