JP2005119591A - Brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device capable of preventing noise, vibration or feeling degradation when determining a trouble of a motor 15. <P>SOLUTION: The brake control device comprises a control valve, G switches 41 and 42, wheel speed sensors 51-54, a brake unit 1, a pump-driving motor 15 to boost the brake fluid pressure, and a drive circuit to output the drive current toward a solenoid valve. The state of the engine cranking or engine start is determined by a control unit 2 from the IGN power supply voltage, and the motor 15 is driven in an engine starting state determined by the control unit 2, and the control unit 2 determines the trouble. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention belongs to the technical field of motor failure determination in a brake control device that improves the braking performance of a vehicle.

In the conventional brake control device, the self-check of the abnormality detection of motor sticking is performed after the IGN is turned on, the motor is operated for a certain period of time, and then the counter electromotive force due to motor inertia rotation at the time of turning off is monitored. When it is changed to, it is determined that the motor lock is abnormal, and the system is shut off and W / L lighting is performed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 7-165055 (page 2-7, full view)

  However, in the conventional brake control device, the first failure determination is performed at the timing of the start of travel, so if there is motor rotation or solenoid driving when the motor is turned on, it will accompany it. There was a problem that operation noise was generated and vibration and feeling deteriorated.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a brake control device capable of preventing noise, vibration, and feeling deterioration during motor failure determination. It is in.

  To achieve the above object, in a brake control device comprising at least a pump capable of returning the brake fluid in the reservoir to the master cylinder side and an electric motor for driving the pump, the engine cranking state or the engine starting state An engine state determination unit that determines the power source voltage and a failure determination unit that drives the electric motor to perform a failure determination. When the failure determination unit determines that the engine is in an engine start state by the engine state determination unit Starts the failure determination by the failure determination means.

  Therefore, the motor operation sound is hidden in the engine start sound at the time of engine start, and sound vibration and feeling deterioration when the motor alone is turned ON can be prevented.

  Hereinafter, an embodiment for realizing a brake control device of the present invention will be described based on Example 1 and Example 2.

First, the configuration will be described.
FIG. 1 is an overall view of the brake control device according to the first embodiment. FIG. 2 is a main part hydraulic circuit diagram of the brake device of the first embodiment.
As shown in FIGS. 1 and 2, the brake control device according to the first embodiment includes a brake unit 1, a control unit 2, a master cylinder 3, G switches 41 and 42, wheel speed sensors 51 to 54, and a wheel cylinder 6. It is said.
As shown in FIG. 2, the brake unit 1 (corresponding to an antilock brake control means) mainly includes switching valves 11 and 12, a reservoir 13, a pump 14, and a motor 15 for driving the pump.

The switching valve 11 switches the state in which the brake fluid pressure from the master cylinder 3 is communicated with the wheel cylinder 6 and the oil path between the master cylinder 3 and the wheel cylinder 6 to the non-communication state.
The switching valve 12 switches between a state in which the brake hydraulic pressure from the master cylinder 3 communicates with the wheel cylinder 6 and a state in which the hydraulic pressure in the wheel cylinder 6 communicates with the reservoir 13.

The reservoir 13 temporarily stores the brake fluid in order to reduce the brake fluid pressure increased to the wheel cylinder 6.
The pump 14 is driven by the motor 15 to return the brake fluid temporarily stored in the reservoir 13 to a brake fluid reserve tank (not shown) on the master cylinder 3 side.
The master cylinder 3 increases the brake fluid pressure to the wheel cylinder 6 due to the driver's brake operation.
The wheel cylinder 6 operates the brakes of the wheels 81, 82, 83, 84 by the brake fluid pressure from the master cylinder 3.
Wheel speed sensors 51 to 54 detect wheel speeds of the respective wheels.
The G switches 41 and 42 detect the vehicle acceleration in the vehicle traveling direction and the yaw direction.

The road surface friction coefficient, vehicle deceleration, etc. are calculated from the control unit 2 (corresponding to engine state determination means and failure determination means), wheel speeds from the wheel speed sensors 51 to 54, and vehicle acceleration from the G switches 41 and 42. Then, the brake unit 1 is controlled.
The IGN monitor of the control unit 2 inputs the battery-side voltage from the relay 25 to the CPU 21 via the interface 22 as shown in FIG. The motor monitor inputs the battery side (upstream) voltage of the motor 15 to the CPU 21 via the interface 23. Further, the voltage on the GND side (downstream) of the motor 15 is input to the CPU 21 via the interface 24. In this way, an IGN monitor and a motor monitor circuit are configured. The transistor 26 is driven by a command from the CPU 21 and turns on the relay 25.

As described above, in the first embodiment, the engine start is detected by the monitor of the IGN power supply, so that a structure with reduced cost can be achieved.
Furthermore, when a system for controlling vehicle behavior (understeer or oversteer) or a system for controlling traction is installed, a more complicated configuration may be used.
Next, the function and effect will be described.

[Effective braking action in ABS system]
An outline of the braking action by the ABS system of this embodiment will be described.
<1> During normal braking / increasing pressure When a brake operation is performed by the driver, the brake fluid pressure is increased by the master cylinder 3 to the wheel cylinder 6 to activate the brakes of each wheel.
Further, when the brake fluid pressure on the wheel cylinder 6 side is reduced and then the brake fluid pressure is increased, the changeover valves 11 and 12 are switched to increase the wheel cylinder side by the master cylinder 3.
<2> During depressurization When the vehicle body deceleration (or slip ratio, etc.) is too close to the slip limit for the road surface condition detected by the control unit 2 during brake operation, the switching valve is operated and the wheel cylinder 6 Side brake fluid pressure is released to the reservoir 13 side, and the brake is released to reduce the vehicle deceleration (or slip ratio, etc.).

<3> During holding For road conditions detected by the control unit 2 when the brake is activated. When the vehicle deceleration (or slip ratio, etc.) is in a good state close to the slip limit, the switching valve is operated to maintain the brake fluid pressure on the wheel cylinder 6 side.
As described above, depending on the road surface condition, the braking performance close to the limit can be achieved in a stable region according to the road surface condition, mainly by switching between the above-described normal braking / increasing pressure, reducing pressure, and holding. You will get it without locking the wheels.

[Determination of failure of pump drive motor]
The pump drive motor 15 in the ABS system is used when the brake fluid temporarily stored in the reservoir 13 is returned to the reservoir tank (not shown) in order to adjust the balance of the entire brake system.
Therefore, in order to operate the ABS system satisfactorily, it is desirable to determine the failure of the motor 15 every time it travels, and to promptly respond to the driver immediately if any abnormality is detected.
In this failure determination, the motor 15 is driven for a predetermined time, and the counter electromotive force due to inertial rotation is detected.

As shown in FIG. 8, when the motor driving for failure determination reaches a predetermined vehicle speed and is set to about 10 km / h so that the determination is performed as early as possible, the driver may be affected by the operating noise and vibration caused by the operation. It will make you feel worse.
On the other hand, the brake control device of the present embodiment makes a determination in the engine start state.

[Flow of failure determination processing]
FIG. 4 is a flowchart showing the flow of the failure determination process executed by the control unit 2 according to the first embodiment. Each step will be described below.

  In step S101, it is determined whether or not the IGN monitor value is below 10V. If it is below, the process proceeds to step S102, and if not, the process proceeds to step S104.

  In step S102, it is determined whether FIGNON, which is an ON flag of IGN, is already in the ON state. If it is in the ON state (FIGNON = 1), the process proceeds to step S103, and if it is not in the ON state, the process proceeds to step S104.

  In step S103, after the IGN power supply is turned on, an LO level storage flag FIG. LONO indicating that the IGN voltage has become low level is set to = 1, and the process proceeds to step S104.

  In step S104, the IGN also determines whether or not the monitor value exceeds 11V. If it exceeds 11V, the process proceeds to step S105, and if it does not exceed 11V, the process proceeds to step S101.

  In step S105, = 1 is set so that FIGNON which is an ON flag of IGN indicates an ON state.

  In step S106, it is determined whether FIGNLO is set to = 1. If FIGNLO is set to 1, the process proceeds to step S111. If FIGNLO is not set to 1, the process proceeds to step S101. To do.

  In step S111, the motor drive signal is actually output to the ON side, and the motor 15 is rotated.

  In step S112, the cell driving motor driving time timer TMR is incremented, and the process proceeds to step S113.

  In step S113, it is determined whether or not the motor driving time counted as TMR has exceeded 350 ms at which the rotational speed is sufficiently increased. If it has exceeded 350 ms, the process proceeds to step S114, and if it has not exceeded 350 ms. The process proceeds to step S112.

  In step S114, the drive of the motor 15 is turned off and the motor 15 is rotated by inertia.

  In step S115, the motor 15 lock determination timer TMR2 is incremented, and the process proceeds to step S116.

  In step S116, it is determined whether TMR2 which has counted the elapsed time as a motor 15 lock determination timer has exceeded 250 ms. If it exceeds 250 ms, the process proceeds to step S117, and if it does not exceed 250 ms, the process proceeds to step S115.

  In step S117, the motor monitor voltage is detected when 250 ms is exceeded, and it is determined whether the motor monitor voltage is less than 9V. If it is less than 9V, the process proceeds to step S118, and if it exceeds 9V, the process proceeds to step S120. To do.

  In step S118, as a process when the motor 15 is normal, the cell check end flag FSELF is set to = 1, and the process proceeds to step S119.

  In step S119, an ABS control routine is started as a normal process.

  In step S120, it is detected that the motor 15 is locked and the monitor voltage is instantaneously restored, and the system is shut down and the W / L (warning lamp) is turned on when it is determined that the motor 15 is abnormal.

[Preventing feeling deterioration during failure judgment]
The failure determination in the brake control device of the first embodiment will be described with reference to the time chart of FIG.
When the driver gets into the vehicle and travels, first, an operation for starting the engine is performed. When this operation is performed, the IGN power is turned on before the start of the cell motor 15 (IGN 0 V → 12 V in FIG. 5).

Thereafter, when the cell motor 15 is activated to enter the engine cranking state, the IGN voltage using the battery 7 as a power source temporarily decreases to about 7 V due to the electric load. This is determined in the process of step S101, and the flag of FIGNLO = 1 is set in the process of step S103.
When the engine starts and the engine speed increases, the alternator starts generating power, and the IGN voltage returns to the steady voltage.
The return of the IGN voltage is determined by the process in step S104, and the motor 15 is driven by the processes in and after step S111 to determine the failure of the motor 15.

  When the engine is started, the engine is controlled so as to have a high engine speed in the initial few seconds with respect to the steady idle engine speed (the part shown as 700 rpm in FIG. 5 as an example) as shown in FIG. The

  The motor 15 for failure determination is driven at a high rotational speed immediately after the start of the engine shown in FIG. Therefore, the driving of the motor 15 for failure determination is not perceived by the driver or the passenger due to the engine start and the engine vibration immediately after the engine start.

In the failure determination process, the drive signal of the motor 15 is output for 100 to 350 ms as shown in FIG. After a predetermined time thereafter (250 ms counted in steps S115 and S116), the occurrence of counter electromotive force due to inertial rotation of the motor 15 is detected by the CPU through the interface by the processing in step S117. The Hi side shown in FIG. Judge by the voltage on the side. In this determination, it is determined that there is a failure when the back electromotive force is not generated and the voltage is restored.
The motor monitor voltage may be detected and determined as a voltage on the Lo side on the GND side of the motor 15.

[Reliable failure judgment]
In the first embodiment, since the motor is driven for failure determination after the start of power generation of the alternator, an alternator power generation power source with less fluctuation can be used as a power source for driving the motor 15.
Therefore, the diagnosis drive of the motor 15 is performed with more stable driving, and the failure determination is reliably performed only with the diagnosis at the time of engine start.
In addition, since the failure determination can be performed when the engine is started before traveling, the occurrence of the abnormality can be transmitted to the driver in the event of an abnormality, so that an earlier response can be promoted.

The second embodiment is an example in which the check timing is determined by determining that the engine is started from the voltage increase speed at which the IGN voltage is reduced.
Since the configuration is the same as that of the first embodiment, the description is omitted.

Next, the operation will be described.
[Flow of failure determination processing]
FIG. 6 is a flowchart showing the flow of a failure determination process executed by the control unit 2 according to the second embodiment. Each step will be described below.

  In step S121, the 50 ms differential value V_IGN50 of the IGN voltage monitor value and the 50 ms differential value V_IGN50_2 before 100 ms are calculated.

  In step S122, the IGN monitor voltage VIGN is confirmed. If VIGN exceeds 11V, the process proceeds to step S123, and if VIGN is 11V or less, the process proceeds to step S125.

  In step S123, it is determined whether or not the absolute value of V_IGN50 is smaller than 0.2V. If the absolute value is smaller than 0.2V, the process proceeds to step S124, and if greater than 0.2V, the process proceeds to step S125.

  In step S124, the engine start timer TENGST is incremented.

  In step S125, the engine start timer TENGST is cleared.

  In step S126, it is determined whether the engine start timer TENGST has exceeded 100 ms. If it has exceeded 100 ms, the process proceeds to step S127, and if it is 100 ms or less, the process proceeds to step S128.

In step S127, it is determined whether or not the 50 ms differential value V_IGN50_2 100 ms before exceeds 1V. If it exceeds 1V, the process proceeds to step S111, and if it is 1V or less, the process proceeds to step S128.
Since S111 and subsequent steps are the same as those in FIG. 4 of the first embodiment, description thereof is omitted.

  In step S128, the VIGN data is sequentially updated so as to be shifted by 10 ms.

  In step S129, it is determined whether 10 ms has elapsed. If 10 ms has elapsed, the process proceeds to step S121, and if 10 ms has not elapsed, the process proceeds to step S129 to wait for the elapse of time.

[Reliable detection of engine start]
In the second embodiment, when the cell motor 15 is activated and the IGN voltage is restored by starting the engine, it is detected by the processing in steps S122 and S123 that the IGN power source has risen again and is stable. Thereafter, the timer value TENGST is incremented and Nms elapses. The IGN voltage with respect to this elapsed time is monitored by the processing of steps S128 and S121.

Nms is adjusted in advance to the transition of the IGN voltage recovery. Therefore, the V_IGN_2 calculation interval corresponds to the voltage recovery interval, and the IGN voltage recovery speed exceeds 1 V (1 V / 50 ms) with respect to 50 ms. This is detected by the process of step S127, and at that time, the motor drive for determining the failure of the motor 15 from step S111 is performed.
Also in the second embodiment, the change in the IGN voltage due to the engine start is reliably detected, and the motor drive sound and vibration for failure determination are hidden by the sound and vibration of the engine start and are detected by the driver and passengers. Not.

[Reliable detection of engine start in consideration of system reset]
In the second embodiment, the engine start is determined based on the voltage increase rate at the portion where the IGN voltage returns. For this reason, even when a system reset occurs due to a voltage drop due to an electrical load when the cell motor 15 is driven to start the engine due to a shortage of the voltage of the battery 7 temporarily lower than the minimum operating voltage of the CPU or the like. The determination process is not affected.
Therefore, even if a system reset occurs, the start of the engine is reliably detected, and the failure diagnosis of the motor 15 can be reliably determined without being affected by the battery power source.

  As mentioned above, although the brake control apparatus of this invention has been demonstrated based on Example 1 and Example 2, it is not restricted to these Examples about a concrete structure, Each claim of a claim is a claim. Design changes and additions are allowed without departing from the gist of the invention.

For example, in the first and second embodiments, two switching valves are provided as electromagnetic valves for adjusting the brake fluid pressure. However, depending on the system configuration, one switching valve or a number of switching valves may be used. May be.
In the first and second embodiments, the wheel speed sensor and the G switch are used as means for detecting the running state. However, other detection means such as a vehicle speed sensor, GPS, and gyro may be used.
The engine state determination means is determined by the CPU provided in the control unit in the embodiment, but may be provided separately outside the control unit, or may be provided in the brake unit 1.

As the failure determination means, in the embodiment, the counter electromotive force due to inertial rotation of the motor is detected, but it may be detected that a predetermined output torque or speed is reached.
The engine state determination means ensures that the engine start is detected only by a decrease in the IGN power supply voltage when the operation time of one time of the cell motor is determined in the control at the start of the vehicle. May be.

Even if it is difficult to determine whether the engine has started or in other situations as a characteristic of the cell motor, the characteristics of the alternator, the characteristics of the IGN power line, or the characteristics of the vehicle system, the previous IGN at a predetermined time interval from the current time The change in voltage is memorized, and when the IGN power supply voltage detected at the present time is restored, the IGN power supply is determined to be engine start when the IGN voltage has changed over a predetermined time. By finely determining according to the characteristics of the voltage, it is possible to more reliably detect engine start and to reliably determine whether the system is reset.
Furthermore, technical ideas other than the claims that can be understood from the above-described embodiments and examples will be described together with the effects thereof.

(A) In the brake control device according to claim 1, the engine state determination means determines that the engine is started by lowering the IGN power supply voltage during engine cranking and then returning. Brake control device.
That is, it is possible to reliably detect the engine start and make a failure determination without taking a complicated configuration.

(B) In the brake device according to claim 1, the engine state determination means determines that the engine is started based on the voltage increase speed at which the IGN power supply voltage decreases and then recovers during engine cranking. Brake control device.
That is, it is possible to reliably determine the engine start, and to reliably detect the engine start even when a system reset occurs due to a low power supply voltage during engine cranking.

(C) The brake control device according to claim 1, wherein when the failure is determined by the failure determination means, the power supplied from the alternator is used as the driving power for the motor.
That is, it is possible to more reliably determine a motor failure with a stable power source.

1 is an overall view of a brake control device according to a first embodiment. It is a principal part hydraulic circuit diagram of the brake device of Example 1. It is a circuit diagram which shows the circuit structure of the part which detects the IGN power supply voltage and motor monitor voltage in the control unit of the brake control apparatus of Example 1. 3 is a flowchart showing a flow of engine start detection and motor abnormality determination processing executed by a control unit of the brake control device of Embodiment 1; 3 is a time chart showing changes in IGN voltage, engine speed, motor drive signal, and motor monitor signal in the brake control device of Embodiment 1; It is a flowchart which shows the flow of the engine start detection performed by the control unit of the brake control apparatus of Example 2, and the abnormality determination process of a motor. It is a time chart which shows the state of the IGN voltage in the brake control apparatus of Example 2, an engine speed, a motor drive signal, and a motor monitor signal. It is a time chart which shows the state of IGN voltage, a vehicle speed signal, a motor drive signal, and a motor monitor signal in the case of determining a motor failure when a predetermined vehicle speed is reached.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake unit 11 Switching valve 12 Switching valve 13 Reservoir 14 Pump 15 Motor 2 Control unit 21 CPU
22 interface 23 interface 24 interface 25 relay 26 transistor 3 master cylinder 41 G switch 42 G switch 51 wheel speed sensor 52 wheel speed sensor 53 wheel speed sensor 54 wheel speed sensor 6 wheel cylinder 7 battery 81 wheel 82 wheel 83 wheel 84 84 wheel

Claims (1)

A master cylinder as a hydraulic source;
A wheel cylinder that applies braking force to the wheels;
Anti-lock brake control means capable of reducing, maintaining and increasing the brake fluid pressure of the wheel cylinder according to the running state of the vehicle;
A reservoir for storing brake fluid during pressure reduction control;
A pump capable of returning at least the brake fluid in the reservoir to the master cylinder side;
An electric motor for driving the pump;
In a brake control device comprising:
Engine state determination means for determining the state of engine cranking or engine start from the power supply voltage;
A failure determination means for driving the electric motor and performing a failure determination;
Provided,
The failure control means starts the failure determination by the failure determination means when the engine state determination means determines that the engine is started.

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