JP2000062589A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a brake force corresponding to a brake force demanded when a feed voltage is lowered. SOLUTION: In a brake control device for a vehicle having a brake force control means to compute a target control amount based on the operation state of a brake operation means by a driver and control a brake force added to a vehicle according to a target control amount, when the generating power of a power source to generate a brake force is in an abnormal state at a step S11, variation of a brake force is prohibited in a region wherein the operation amount change of a brake operation means is low. And, in a region wherein the change of an operation amount of the brake operation means is high, a brake force is controlled at a step S12 based on an operation amount of the brake operation means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking control device for controlling a braking force applied to a vehicle in accordance with a target control amount determined based on a driver's operating state of a brake.

[0002]

2. Description of the Related Art Conventionally, there is a device for stopping the duty control of an electromagnetic valve and fixing the opening degree of the electromagnetic valve to a constant value when the supply voltage to the electromagnetic valve provided in a brake pressure control circuit decreases. (See Japanese Patent Laid-Open No. 7-17375). In this device, by fixing the opening degree of the electromagnetic valve to a constant value, a constant braking force is ensured even when the voltage supplied to the electromagnetic valve is reduced.

[0003]

However, when the duty control is stopped, the brake pressure becomes constant, so that even if the required braking force is large, only a constant braking force is obtained and the vehicle braking is performed. There was a problem that it deteriorated.

An object of the present invention is to obtain a braking force corresponding to the required braking force even when the supply voltage drops.

[0005]

According to a first aspect of the present invention, there is provided a vehicle braking control device for calculating a target control amount based on an operation state of a brake operating means by a driver and adding the target control amount to a vehicle according to the target control amount. In a vehicle braking control device including a braking force control means for controlling a braking force, a power source for generating the braking force controlled by the braking force control means, for example, generated power such as hydraulic pressure or voltage is in an abnormal state. Occasionally, the braking force control means prohibits a change in the braking force in an area where the operation amount change of the brake operation means is small, and operates the brake operation means in an area where the operation amount change of the brake operation means is large. The braking force is controlled based on a change in the amount.

According to a second aspect of the present invention, there is provided a vehicle braking control device which controls the braking force by controlling the brake hydraulic pressure by the vehicle braking control device of the vehicle braking control device according to the first aspect. The abnormal state is characterized in that the hydraulic pressure supply from the hydraulic pressure supply source is abnormal.

According to a third aspect of the present invention, there is provided a vehicle braking control device of the first aspect, wherein the vehicle braking control device of the first aspect controls the braking oil pressure by an electromagnetic valve to control the braking force. A voltage supply means for controlling, wherein the abnormal state generates a voltage to be supplied to the solenoid valve,
For example, the in-vehicle battery, the alternator, etc. are in an abnormal state.

According to a fourth aspect of the present invention, there is provided the vehicle braking control device according to the first aspect, wherein the vehicle braking control device increases or decreases the braking force based on a change in the operation amount of the brake operating means. The increase / decrease amount of the braking force in the abnormal state and when the change in the operation amount of the brake operating means is large is set smaller than the increase / decrease amount of the braking force in the states other than the abnormal state. It is characterized by being.

According to the vehicle braking control device of the first to fourth aspects, when the generated power of the power source for generating the braking force is in the abnormal state, the change amount of the brake operating means is small. Since the change of the braking force is prohibited in, the energy consumption of the power source can be reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an electronically controlled brake device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a hydraulic circuit diagram of the electronically controlled braking device 10. This electronically controlled brake device 10 has a master cylinder 14 that pumps brake oil in response to a driver's depression of a brake pedal 12.

A stroke simulator 18 incorporating a piston 18a and a spring 18b is connected to the master cylinder 14 via a normally open simulator cut valve 16. Further, a master pressure sensor 20 for detecting the pressure in the master cylinder 14 is provided between the master cylinder 14 and the simulator cut valve 16.

To the reservoir 22, one end of a hydraulic pressure supply conduit 24 and one end of a hydraulic pressure discharge conduit 26 are connected. An oil pump 30 that is driven by an electric motor 28 is provided in the middle of the hydraulic pressure supply conduit 24, and an accumulator 32 that stores the hydraulic pressure increased to about 120 atmospheric pressure by the oil pump 30 is provided.

The other end of the hydraulic pressure supply conduit 24 is connected to a wheel cylinder 36 for the left front wheel via a hydraulic supply conduit 34FL for the left front wheel.
It is connected to the FL and is connected to the wheel cylinder 36FR for the right front wheel via the hydraulic supply conduit 34FR for the right front wheel. The other end of the hydraulic supply conduit 24 is connected to the wheel cylinder 36RL for the left rear wheel via the hydraulic supply conduit 34RL for the left rear wheel, and the wheel for the right rear wheel is connected via the hydraulic supply conduit 34RR for the right rear wheel. It is connected to the cylinder 36RR.

Similarly, the other end of the hydraulic discharge conduit 26 is connected to the wheel cylinder 36FL for the left front wheel via the hydraulic discharge conduit 38FL for the left front wheel, and the wheel cylinder for the right front wheel via the hydraulic discharge conduit 38FR for the right front wheel. It is connected to 36FR. The other end of the hydraulic pressure discharge conduit 26 is connected to the left rear wheel wheel cylinder 36RL via a hydraulic pressure discharge conduit 38RL for the left rear wheel.
And is connected to the wheel cylinder 36RR of the right rear wheel via the hydraulic discharge conduit 38RR for the right rear wheel.

Hydraulic supply conduits 34FL, 34FR, 34RL, 3
Normally closed electromagnetic flow control valve 40F in the middle of 4RR
L, 40FR, 40RL and 40RR are provided, and normally closed electromagnetic flow control valves 42FL, 42FR and 42RL are provided in the middle of the hydraulic pressure discharge conduits 38FL, 38FR, 38RL and 38RR, respectively.
42RR is provided. In addition, the wheel cylinder 36
Pressure sensors 44FL, 44FR, 4 to detect the respective pressures in FL, 36FR, 36RL and 36RR
4RL and 44RR are provided.

FIG. 2 is a block diagram of the electronically controlled brake device 10. Reference numeral 50 in the figure denotes a microcomputer, which is a central processing unit (CPU) 50.
a, a read only memory (ROM) 50b, a random access memory (RAM) 50c, an input unit 50d and an output unit 50e, which are bidirectional common buses 50f.
Are connected to each other by.

Input unit 50d of the microcomputer 50
Is a signal indicating the pressure in the master cylinder 14 output by the master pressure sensor 20, and pressure sensors 44FL to 4FL.
A signal indicating the pressure in the wheel cylinders 36FL to 36RR, a signal indicating the current value generated by the alternator 52, and a signal indicating the voltage value of the vehicle-mounted battery 54 are input from the 4RR. On the other hand, via the output unit 50e,
Simulator cut valve 16, electromagnetic flow control valve 40FL-4
0RR, 42FL to 42RR, a control signal is output to the electric motor 28 for driving the pump 30.

In this electronically controlled brake device 10, when the brake pedal 12 is operated, the pressure inside the master cylinder 14 is detected by the master pressure sensor 20, and inside the master cylinder 14 detected by this master pressure sensor 20. The target control amount is calculated based on the pressure of. Then, the braking force applied to each wheel is controlled by controlling the pressure (brake hydraulic pressure) in the wheel cylinders 36FL to 36RR based on this target control amount.
That is, the microcomputer 50 uses the electromagnetic flow control valve 4
By outputting a control signal to 0FL to 40RR,
By controlling the opening and closing of the electromagnetic flow control valves 40FL to 40RR, the pressure in the wheel cylinders 36FL to 36RR is increased to the pressure corresponding to the target control amount, and the braking force applied to each wheel is increased. In addition, the electromagnetic flow control valve 40
By outputting a control signal to FL to 40RR, the electromagnetic flow control valves 40FL to 40RR are closed, and by outputting a control signal to the electromagnetic flow control valves 42FL to 42RR, an electromagnetic flow control valve is output. By controlling the open / closed state of 42FL to 42RR, the wheel cylinders 36FL to 3FL
The pressure in 6RR is reduced to the pressure corresponding to the target control amount, and the braking force applied to each wheel is reduced.

Next, with reference to the flow chart shown in FIG. 3, the electronically controlled brake device 10 according to this embodiment.
The braking force control in step 1 will be described. First, the CPU 50a of the microcomputer 50 monitors the power source (step S10). That is, as shown in the flow chart of FIG. 4, it is judged whether or not the alternator 52 is normal based on the signal indicating the current value generated by the alternator 52 (step S100), and the motor for driving the pump 30 is determined. It is determined whether or not the pump 30 is normal based on the current value supplied to 28 (step S101), and the voltage of the on-vehicle battery 54 is normal or lower based on the signal indicating the voltage value of the on-vehicle battery 54. It is determined whether or not it is (step S102).

If it is determined that the alternator 52, the pump 30 and the vehicle battery 54 are all normal, the power source is determined to be normal (step S103).
On the other hand, if it is determined that the alternator 52 or the pump 30 is abnormal, or if the voltage of the on-vehicle battery 54 is low, it is determined that the power source is down (step S104).

Next, it is determined whether or not the power source is down (step S11), and if it is determined that the power source is down, power save control is performed (step S11). S12), if it is determined that the power source is not down, normal control is performed (step S13).

Here, the normal control means the pressure in the master cylinder 14 and the wheel cylinder 36FL as shown in FIG.
Based on the deviation (hydraulic pressure deviation) from the pressure in 36RR to 36RR, the control signal is constantly output to the electromagnetic flow control valves 40FL to 40RR and 42FL to 42RR to increase or decrease the pressure in the wheel cylinders 36FL to 36RR. It refers to the control to perform.

On the other hand, the power save control is a region where the hydraulic pressure deviation is small as a dead zone, and when the hydraulic pressure deviation becomes larger than a predetermined value, the electromagnetic flow control valves 40FL to 40RR, 42.
By outputting a control signal to FL to 42RR, the pressure in the wheel cylinders 36FL to 36RR is increased, and when the hydraulic pressure deviation becomes smaller than a predetermined value, the electromagnetic flow control valves 40FL to 40RR, By outputting a control signal to 42FL to 42RR, the wheel cylinder 36
It is a control for reducing the pressure in FL to 36RR.

FIG. 6 shows changes in the target hydraulic pressure (hydraulic pressure corresponding to the brake operation amount), the hydraulic pressure during normal control, and the hydraulic pressure during power save control, as well as the hydraulic pressure during power save control. The timing of pressure increase / decrease is shown. Generally, during normal control, pressure increase and decrease are repeated due to subtle fluctuations in the target hydraulic pressure due to foot vibrations when the brake pedal is depressed, resulting in severe wear of the power source (power source, etc.). On the other hand, according to the power save control, since the dead zone is a region where the hydraulic pressure deviation is small, the pressure increase and the pressure decrease are not repeated even when the target hydraulic pressure slightly changes. That is, as shown in FIG. 6, when increasing the pressure, the pressure is continuously increased for a certain period, and when decreasing the pressure, the pressure is continuously reduced for a certain period. Therefore, since the consumption of the power source can be suppressed, even when the power source is down, the controllable time can be extended in a nearly normal state.

Further, as shown in FIG. 6, in the power save control, the increase / decrease amount of the hydraulic pressure when the target hydraulic pressure is large (when the change in the brake operation amount is large) is set smaller than that in the normal control. There is. This can also reduce the consumption of the power source. Further, by performing the power save control, there is an effect that the driver can recognize the occurrence of the failure because the operation feeling is different.

In the above-described embodiment, the present invention is applied to a so-called electronically controlled brake, which has a target hydraulic pressure based on the operating force of the brake and controls the brake hydraulic pressure by the solenoid valve based on the target hydraulic pressure. Although the case where the present invention is applied has been described, the present invention can also be applied to a brake device of a type that has a target hydraulic pressure based on the brake operating force and the like, and controls the braking force with a motor based on the target hydraulic pressure. is there.

[0027]

According to the present invention, when the generated power of the power source for generating the braking force is in an abnormal state, the change of the braking force is prohibited in the region where the change of the operation amount of the brake operating means is small. The energy consumption of the source can be reduced.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an electronically controlled brake device according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of an electronically controlled braking device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing braking control of the electronically controlled braking device according to the embodiment of the present invention.

FIG. 4 is a flowchart showing power source monitoring according to the embodiment of the present invention.

FIG. 5 is a graph for explaining a dead zone of power save control according to the embodiment of the present invention.

FIG. 6 is a graph showing changes in the target hydraulic pressure, the hydraulic pressure during normal control and the hydraulic pressure during power save control, and the timing of increasing and decreasing the hydraulic pressure during power save control according to the embodiment of the present invention.

[Explanation of symbols]

10 ... Electronically controlled braking device, 12 ... Brake pedal,
14 ... Master cylinder, 16 ... Simulator cut valve,
18 ... Stroke simulator, 20 ... Master pressure sensor, 22 ... Reservoir, 24 ... Hydraulic supply conduit, 26 ... Hydraulic discharge conduit, 30 ... Oil pump, 32 ... Accumulator, 36FL-36RR ... Wheel cylinder, 40FL-40
RR, 42FL to 42RR ... Electromagnetic flow control valve, 52 ... Alternator, 54 ... In-vehicle battery.

Claims (4)

[Claims] 1. A vehicle braking control including a braking force control means for calculating a target control amount based on an operation state of a brake operating means by a driver and controlling a braking force applied to a vehicle according to the target control amount. In the device, when the generated power of the power source for generating the braking force controlled by the braking force control unit is in an abnormal state, the braking force control unit controls the operation amount of the brake operating unit in a small region. Prohibiting the change of the braking force,
A braking control device for a vehicle, wherein the braking force is controlled based on a change in the operation amount of the brake operation means in a region where the change in the operation amount of the brake operation means is large. 2. The vehicle braking control device controls the braking force by controlling brake hydraulic pressure, and the abnormal state is a state in which hydraulic pressure supply from a hydraulic pressure supply source is abnormal. The braking control device for a vehicle according to claim 1. 3. The vehicle braking control device controls the braking force by controlling a brake hydraulic pressure with a solenoid valve, and in the abnormal state, a voltage supply for generating a voltage supplied to the solenoid valve. The vehicle braking control device according to claim 1, wherein the means is in an abnormal state. 4. The vehicle braking control device increases or decreases the braking force based on a change in the operation amount of the brake operating means, and is in the abnormal state, and when the change in the operation amount of the brake operating means is large. The braking control device for a vehicle according to claim 1, wherein the increase / decrease amount of the braking force in is set to be smaller than the increase / decrease amount of the braking force in a state other than the abnormal state.