JPH0872693A - Fault detection for anti-skid device - Google Patents

Abstract

PURPOSE: To provide a fault detection for ABS device which can detect a power short circuit fault in a motor relay circuit positively immediately after main power is turned on. CONSTITUTION: By turning on a main relay at a prescribed time after turning on main power and monitoring voltage between a pump motor and a motor relay for a prescribed time, some fault of the motor relay is detected. The time t1 from main power on to the main relay on is made relatively longer than the fault detection time t2 of the motor relay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of detecting a failure of an anti-skid device for an automobile (hereinafter referred to as an ABS device), and more particularly to a method of detecting a failure of a motor relay system circuit for controlling a pump motor.

[0002]

2. Description of the Related Art An ABS device for a vehicle is provided with a solenoid valve 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 so that the wheel is skided by sudden braking. When approaching, the solenoid valve alternately decreases and increases the brake pressure to prevent the wheels from reaching the skid state, and stable running performance can be maintained.

The ABS device is provided with a pump that pumps the brake fluid in the reservoir to the dynamic pressure side. The pump motor that drives this pump operates during the ABS control and stops when the ABS control ends. This pump motor is controlled by a motor relay. The excitation circuit of the motor relay is usually configured such that its upstream side can be switched between a power source side and a ground side via a main relay, and the downstream side is controlled by an anti-skid controller (hereinafter simply referred to as a controller).

By the way, the ignition switch is turned on.
After that, in order to detect the short-circuit failure of the main relay,
The main relay is off for a certain period. However, if the downstream side of the motor relay excitation circuit and the controller are shorted to the power supply side, current will flow in the motor relay excitation circuit until the main relay is turned on after the ignition switch is turned on. Relay is O
N, the pump motor rotates. Then, when the main relay is turned on, the motor relay is turned off, and the rotation of the pump motor is stopped.

[0005]

In order to detect a failure of the motor relay circuit, the controller monitors the voltage between the pump motor and the motor relay (motor voltage). By turning on the motor relay with the ignition switch on and the main relay on,
The motor voltage rises, and when the motor relay is turned on, it gradually falls. When a short circuit failure of a motor relay is detected by the motor voltage, in order to prevent erroneous detection, when the motor relay is OFF, the state where the motor voltage is at the H level is a predetermined detection time (for example, 1 when the motor voltage falls). If it occurs continuously, it is detected as a failure. However, if the time from when the ignition switch is turned on to when the main relay is turned on is shorter than the failure detection time of the motor relay, the power supply short-circuit failure of the motor relay system circuit cannot be detected immediately after the ignition switch is turned on.

Therefore, an object of the present invention is to provide a method of detecting a failure of an ABS device, which can detect a power supply short circuit failure of a motor relay system circuit immediately after the main power supply is turned on.

[0007]

A failure detecting method of the present invention is to switch a main relay to a power supply side after a predetermined time from turning ON of a main power supply and monitor a voltage between a pump motor and a motor relay for a predetermined time. Thus, the failure detection of the motor relay is performed, and the period from the turning on of the main power supply to the switching of the main relay from the ground side to the power supply side is made relatively longer than the failure detection time of the motor relay.

[0008]

Operation When the ignition switch (power supply) is turned on, the main relay is off and the motor relay is off. Therefore, if the motor relay circuit is normal, the motor voltage remains at the L level. But,
When the power supply is short-circuited on the downstream side of the excitation circuit of the motor relay, the motor starts rotating from the time when the ignition switch is turned on, and the motor voltage also rises. The motor voltage becomes H level by turning on the ignition switch. If this state continues for a certain period of time, the controller detects that the excitation circuit of the motor relay has a power supply short circuit failure and prohibits the ABS control. If no failure is detected, after the failure detection time of the motor relay has elapsed,
Turn on the main relay (switch to the power supply side).

[0009]

1 is a system diagram of a vehicle ABS device according to the present invention. In the figure, reference numeral 1 is a controller composed of a microcomputer or the like, which controls each part of this system and diagnoses a failure. 2 is a vehicle battery, 3 is a brake switch that is turned on in response to the operation of the brake pedal, 4 is a brake lamp that notifies the operation state of the brake pedal, and when the brake pedal is depressed, the brake switch 3 is turned on and the brake lamp 4 Lights up. The ON / OFF signal of the brake switch 3 is input to the T ₁ terminal of the controller 1. 5, 6, 7,
Reference numeral 8 is a wheel speed sensor that independently detects the wheel speeds of the four wheels, and the detection signals of these sensors 5-8 are input to the controller 1, respectively.

A pump motor 10 drives a pump for pumping the brake fluid in the reservoir to the dynamic pressure side. The normally open contact 11a of the motor relay 11 is connected in series with the pump motor 10, and the voltage of the pump motor 10 is monitored by the T ₂ terminal of the controller 1. The upstream side of the coil 11b of the motor relay 11 is connected to a contact 15a of the main relay 15 described later, and the downstream side is connected to the T ₃ terminal of the controller 1. G of controller 1
The terminal is connected to the vehicle body and is always grounded. The voltage of the battery 2 is constantly input to the B terminal of the controller 1, and when any failure is detected, it is backed up so that the failure code can be stored in the memory in the controller 1 even after the ignition switch 12 is turned off.

Reference numeral 12 is an ignition switch which is a main power switch, and a signal from the ignition switch 12 is input to the T ₄ terminal of the controller 1. The ignition switch 12 is connected in series with an alarm lamp 13, and further passes through a diode 14 to connect the main relay 1
5 is connected in series to the contact 15a. Main relay 15
When the ABS system fails, the alarm lamp 13 is turned on and the solenoid valve 20, which will be described later, is turned off to restore the normal braking function. The alarm lamp 13 is also connected to the W terminal for lamp control of the controller 1, and by turning on the W terminal (internal conduction with the G terminal), the alarm lamp 13 can be turned on regardless of the main relay 15. it can. The coil 15b of the main relay 15 is controlled by the R terminal of the controller 1. When the coil 15b is not energized, the contact 15a is grounded (OFF) and the alarm lamp 13 is turned on. When the coil 15b is energized, the contact 15a is turned on and the alarm lamp 13 is turned off.

The diode 14 is connected to the circuit via the connector 21, and the diode 14 is connected to the connector 2
It is detachable with respect to 1. Therefore, the diode 14
Alarm lamp 1 by removing the connector 21
3 and the main relay 15 can be electrically opened. Contact 15 between the diode 14 and the main relay 15
The coil 11b of the motor relay 11, the solenoid valve 20, and the monitor M terminal of the controller 1 are connected between a and a.

The solenoid valve 20 is a valve for reducing or increasing the brake pressure. For example, two solenoid valves are provided for each wheel.
There are 8 in total. Solenoid valve 20
The downstream side of each is connected to the controller 1.
Therefore, when the main relay 15 is turned off, the motor relay 11 and the solenoid valve 20 are also turned off, and the voltage of the M terminal also becomes L level. When the main relay 15 is turned on, the motor relay 11 and the solenoid valve 20 become operable for the first time, and the voltage at the M terminal becomes H.
It becomes a level.

FIG. 2 is a time chart for detecting a failure of the exciting circuit 22 of the motor relay 11. When the exciting circuit 22 between the downstream side of the coil 11b of the motor relay 11 and the controller 1 is short-circuited to the power source side, after turning on the ignition switch 12, the main relay 1
During the period t ₁ before turning on 5, the current flows through the coil 11b of the motor relay 11, so the motor relay 11 is turned on and the pump motor 10 rotates. Then, when the main relay 15 is turned on, the motor relay 1
1 is turned off, and the rotation of the pump motor 10 is stopped. The motor voltage V _MS monitored at the terminal T ₂ is always at the L level if the circuit is normal. However, if the exciting circuit 22 has a power short-circuit fault as described above, it is at the H level immediately after the ignition switch 12 is turned on. Then, when the main relay 15 is turned on, the voltage gradually decreases and becomes the L level. Therefore, the detection time t ₂ commensurate with the fall of the motor voltage V _MS is required to detect the failure of the exciting circuit 22. By the way, as shown by a broken line in FIG. 2, there is a period in which the ignition switch 12 is turned on immediately before the ignition switch 12 is turned on, and the ignition switch 12 is turned on.
If the pump motor 10 during the period is rotating as the control of the normal, the rotation of the motor 10 is stopped at the moment that OFF the ignition switch 12, the motor voltage V _MS
Gradually decreases. Immediately after that, if the ignition switch 12 is turned on and the main relay 15 is turned on immediately after that, there is a possibility that the power supply short circuit fault may be erroneously detected despite the motor 10 being rotated normally. Therefore, in the present invention, the failure of the exciting circuit 22 is detected by making the time t ₁ until the main relay 15 is turned on relatively longer than the detection time t ₂ .

FIG. 3 is a flow chart of an example of a method of detecting a power source short circuit failure of the exciting circuit 22. First, when the ignition switch 12 is turned on, whether the elapsed time t from turning on exceeds the set time t ₂ , that is, the failure detection time t ₂
It is determined whether or not has passed (step S ₁ ). When the detection time t ₂ has elapsed, the motor voltage V _MS is monitored (step S ₂ ), and if the motor voltage V _MS is at the L level, it is normal (it is not a power supply short circuit failure of the excitation circuit 22).
Is determined (step S _3), the ignition switch O
When the time t from N has passed the predetermined period t ₁ (step S ₄ ), the main relay 15 is turned on (step S ₅ ). On the other hand, in step S ₂ , the motor voltage V _MS
There if H level, determines that the power supply short circuit failure of the excitation circuit 22 (step S _6), and stores the fault codes relevant (step S _7). Then, the prohibiting ABS control, and ON the W terminal, is continuously lit on the alarm lamp 13 (Step S _8).

As a method for detecting the failure of the exciting circuit 22, the detection time t ₂ is set in advance as described above, and the period t ₁ from turning on the ignition switch 12 to turning on the main relay 15 is time t _1. Besides the method of making it longer than ₂ , there is a method of making the period t ₁ longer than the detection time t ₂ only when the motor voltage V _MS exceeds the set value.

[0017]

As is apparent from the above description, according to the present invention, the time from the turning on of the main power supply to the turning on of the main relay is made longer than the failure detection time of the motor relay, so that the motor relay is excited. Whether or not the power supply short circuit failure has occurred on the downstream side of the circuit can be detected immediately after the ignition switch is turned on.

[Brief description of drawings]

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

FIG. 2 is a time chart diagram of an example of a failure detection method according to the present invention.

FIG. 3 is a flowchart of an example of a failure detection method according to the present invention.

[Explanation of symbols]

 1 Controller 10 Pump Motor 11 Motor Relay 12 Ignition Switch 13 Alarm Lamp 15 Main Relay 22 Excitation Circuit

Claims (1)

[Claims] 1. A solenoid valve 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, and the solenoid valve alternates between depressurization and pressurization of the brake pressure. This is an anti-skid device that prevents the wheels from skiding by performing a pump motor that pumps the brake fluid to the dynamic pressure side, and a motor relay that controls this motor. In the circuit in which the upstream side of the circuit can be switched to the power source side and the ground side through the main relay and the downstream side is controlled by the anti-skid controller, the main relay is switched to the power source side for a predetermined time after the main power source is turned on. And switch the voltage between the pump motor and motor relay for a specified time. According to the above, the motor relay failure detection is performed, and the period from the turning on of the main power supply to the switching of the main relay from the ground side to the power supply side is made relatively longer than the failure detection time of the motor relay. Anti-skid device failure detection method.