KR20040007779A - The control method of Electro hydraulic brake system - Google Patents

Abstract

PURPOSE: A method for controlling an EHB(Electro Hydraulic Brake System) is provided to quickly a braking intension of a driver when the driver operates a brake pedal by detecting movement distance of the brake pedal, turning-on/off states of a braking lamp, and the pressure change of a master cylinder, to perform operations for a valve necessary for braking in advance, and accordingly to rapidly control the pressure of a brake. CONSTITUTION: A method for controlling an EHB is composed of steps of sensing movement distance of a brake pedal, turning-on/off states of a braking lamp, and the pressure change of a master cylinder when a driver operates the brake pedal(S10); comparing the sensed movement distance of the brake pedal with a set reference value(S20); closing first and second cut valves if the sensed movement distance of the brake pedal is larger than the set reference distance value(S30); opening a third cut valve(S40); checking if a braking lamp is turned on or off(S50); executing a braking action and returning if the braking lamp is turned on(S60); opening first and second cut valves if the movement distance of the brake pedal is smaller than the set reference distance value(S21); closing the third cut valve(S22); releasing the braking action and returning(S23); comparing the pressure of the master cylinder with a set reference pressure if the braking lamp is turned off(S51); and performing the braking action if the pressure of the master cylinder is larger than the set reference pressure(S60).

Description

The control method of Electro hydraulic brake system

The present invention relates to a control method of an electro-hydraulic braking apparatus, and more particularly, to a control method of an electro-hydraulic braking apparatus that can grasp a driver's braking intention and set a valve operation in a braking preparation stage based on the driver's braking intention.

In general, a vehicle is equipped with a brake system for stopping and speed control, and recently, an anti-lock brake system (hereinafter referred to as an anti-lock brake system) is used to improve the braking ability of the vehicle and to secure steering stability during braking. ABS is called).

ABS prevents the phenomenon by detecting the wheels during braking in advance to prevent the vehicle from slipping due to the failure to transfer the braking force to the road surface when braking during high-speed driving on roads with low braking friction coefficient. It is a system for doing so.

That is, the system estimates the vehicle speed by using the wheel speed sensor installed on the front and rear wheels of the vehicle, calculates the current slip rate and deceleration based on this, and sets the vehicle as the input variable. The slip rate is repeated by predicting the occurrence of the condition and reducing the brake pressure beforehand to bring the wheel speed closer to the vehicle speed and again increasing the brake pressure to brake the wheel before the wheel speed exceeds a certain value. By controlling to keep the vehicle in a desirable state, the fixed state of the wheels is generated to prevent the loss of steering stability and running stability in advance and to improve the braking ability.

Recently, the brake device is being introduced to understand the braking intention of the driver so that the brake can be operated smoothly in an emergency.

In the conventional electro-hydraulic braking system, the braking intention of the driver is detected by detecting whether the braking light is on / off, the travel distance of the brake pedal, the pedaling force of the brake pedal, the pressure of the master cylinder, and the like to determine the braking intention of the driver.

However, the method of detecting the driver's braking intention by detecting whether the brake light is on or off or the rate of change of the pressure signal of the master cylinder is controlled even when the vehicle is vibrated due to unevenness. Since the pressure signal is operated at the end, there is a problem that the reliability is low or the immediate response is slow during sudden brake.

Accordingly, in the present invention, when the brake pedal is operated by the driver by sensing the movement distance of each brake pedal, whether the brake light is on / off or the pressure change of the master cylinder, the driver quickly determines the willingness of the driver's braking, By performing the valve operation required in advance, it is possible to control the brake pressure quickly.

1 is a hydraulic circuit diagram showing an electro-hydraulic braking control device for a vehicle of the present invention.

2 is a flow chart showing a control method of the electrohydraulic brake system of the present invention.

* Description of the symbols for the main parts of the drawings *

1: electronic control unit 10: brake pedal

11: brake light detection means 12: pedal travel distance detection means

30: oil tank 40: master cylinder

41: pressure sensing unit 50: pump

51: motor 60: accumulator

70: emergency flow path 80: pedal simulator

In order to achieve the above object, the present invention is a step of receiving the at least one vehicle state change data when the brake pedal is operated by the driver (S10), the at least one vehicle state change data and the input Comparing reference setting data sequentially, providing a braking standby state if the setting data is larger than or different from the reference setting data, and then braking or releasing the braking standby state. It consists of.

Hereinafter, with reference to the accompanying drawings 1 and 2 will be described a preferred embodiment of the present invention.

1 is a hydraulic circuit diagram showing an electromagnetic hydraulic brake control apparatus for a vehicle of the present invention, Figure 2 is a flow chart showing a control method of the electrohydraulic brake apparatus of the present invention.

First, referring to Figure 1, the configuration,

Brake light sensing means for turning on / off as the wheel cylinder A installed at the front wheels FR and FL and the rear wheels RR and RL, the brake pedal 10 provided at one side of the driver's seat, and the brake pedal 10 are operated ( 11), the pedal movement distance detection unit 12, the oil storage tank 30, the brake oil is stored, and the master cylinder (40) to cause brake operation by supplying brake hydraulic pressure to the wheel cylinder (A) ), An accumulator 60 for temporarily storing the brake hydraulic pressure supplied from the master cylinder 40, and a pump 50 for supplying the brake hydraulic pressure accumulated in the accumulator 60 to the wheel cylinder A. And a motor 51 for driving the pump 50.

In addition, an input side normal closing valve 71 is provided between the oil tank 30 and the wheel cylinder A to control the brake hydraulic pressure transmitted from the oil tank 30 to the wheel cylinder A. The output side normal close valve 72 is provided in the flow path returned from the cylinder A to the oil tank 30.

In addition, in order to supply the hydraulic pressure to the front wheel side (FF, FR) wheel cylinder (A) directly from the master cylinder in preparation for the occurrence of a failure of the flow path constituted in the oil tank 30 and each wheel cylinder (A). The emergency flow path 70 is configured, and the emergency flow path 70 has pressure sensing for sensing the pressure of the first and second cut valves CV1 and CV2 and the master cylinder 40, which are configured to prevent hydraulic pressure from operating in normal times. The part 41 is comprised.

One side of the emergency passage 70, the pedal simulator 80 for simulating the brake operation movement distance in accordance with the force to operate the brake pedal having the operation movement distance, and the third cut for controlling the hydraulic pressure of the pedal simulator (80) The valve CV3 is configured.

In addition, the electronic control unit 1 for controlling the braking operation of the hydraulic braking device by comparing and determining the data detected by the braking light detecting means 11, the pedal travel distance detecting unit 12, and the master cylinder pressure detecting unit 41. It consists of.

The control method of the electromagnetic hydraulic brake control apparatus for a vehicle configured as described above is illustrated in FIG. 2, which will be described with reference to FIG. 2.

When the brake pedal is operated by the driver, detecting whether the brake light is on / off, the movement distance of the brake pedal, the pressure change of the master cylinder (S10), and comparing the detected movement distance of the brake pedal with a reference set value. (S20) and closing the first and second cut valves (S30) and opening the third cut valve when the movement distance of the brake pedal sensed in the step (S20) is greater than the set distance value. (S40), and then checking whether the braking light is on or off (S50), and if the braking light is on, performing a braking operation and returning to step S10 (S60), and in the step S20 If the travel distance of the brake pedal is smaller than the set reference travel distance value, opening the first and second cut valves (S21), closing the third cut valve (S22), and then canceling the braking operation In step S23 to return to (S10), and in the step (S50) When the braking light is turned off, comparing the pressure of the master cylinder with the set reference pressure (S51). If the pressure of the master cylinder is large in step S51, the braking operation is performed (S60). It is a process of moving.

When the brake pedal 10 is operated by the driver, the electronic controller 1 inputs data from the brake light detector 11, the brake pedal travel distance detector 12, and the master cylinder pressure detector 40 to provide the hydraulic pressure. It controls the braking operation of the braking device.

In general, when the brake pedal 10 operates, the movement distance of the brake pedal 10 changes, and when the movement distance is more than the set distance, the brake light is turned on and the hydraulic pressure of the master cylinder 40 increases. The braking operation is performed.

The electronic controller 1 compares the travel distance value input from the brake pedal travel distance detection unit 12 with a preset travel distance value, and closes the first and second cut valves CV1 and CV2 when the input travel distance value is large. The third cut valve CV3 is opened.

Subsequently, when the braking light is turned on by determining whether the braking light is on or off, it is determined as a braking operation to drive the pumping motor 51 to supply hydraulic pressure to the wheel cylinder A to perform braking.

When the travel distance value of the brake pedal is smaller than the set travel distance value, the first and second cut valves CV1 and CV2 are opened, the third cut valve CV3 is closed, and the hydraulic control device is maintained at an initial standby state. Done.

In addition, when the braking light is turned off by judging whether the braking light is on or off, the pressure of the master cylinder 40 is compared with the reference setting pressure value. When the pressure value of the master cylinder 40 is greater than the reference setting pressure value, the braking operation is performed. If it is small, the first and second cut valves CV1 and CV2 are opened, the third cut valve CV3 is closed, and the hydraulic control device is maintained at an initial standby state.

That is, when the brake pedal 10 is operated by the driver, the moving distance is sensed, and when the brake pedal 10 is over the set value, the brake pedal 10 is prepared to prepare the braking operation by controlling the respective cut valves CV1, CV2, and CV3. Check the pressure in 40 to perform braking or maintain the initial standby state.

As described above, in the present invention, when the brake pedal is operated by the driver, the moving distance is sensed, and if the set value is greater than or equal to the set value, the brake valve is prepared to prepare a braking operation by checking the pressure of the braking light and the master cylinder. By performing or maintaining the initial standby state, it is possible to perform a quick and accurate braking operation at the time of sudden braking by the driver to provide a reliable braking device to the user.

Claims (5)

In a vehicle hydraulic brake control device controlled by an electronic control device, In the braking mode, receiving at least two vehicle state change data, sequentially comparing the two or more vehicle state change data and reference setting data according to a set order, and any one setting in the comparing step. When the data and the reference setting data correspond to the set comparison information, preparing a braking standby state; when the other setting data and the reference setting data correspond to the setting values, braking of the vehicle is performed; And comparing with the reference setting data and performing a braking if it corresponds to a set value, and releasing a braking standby state if not. The method of claim 1, The at least one plurality of vehicle state change data are on / off of a brake light, a travel distance of a brake pedal, pressure data of a master cylinder, and the comparison order is a travel distance of a brake pedal, whether a brake light is on / off, or a master cylinder. Control method of an electromagnetic hydraulic brake device characterized in that the pressure data. The method of claim 1 or 2, wherein the step of preparing the braking standby state is: Comparing the detected movement distance of the brake pedal with the reference set distance value (S20) is greater than the set distance value to close the first and second cut valve (S30) and the step of opening the third cut valve (S40) A control method for an electrohydraulic brake system, characterized in that. The method of claim 1 or 2, wherein the braking or releasing the braking standby state after the vehicle prepares the standby state comprises: After the preparation of the braking standby state, checking whether the braking light is on or off (S50), performing a braking operation when the braking light is on, and returning to step S20 (S60), and in the step S20 If the travel distance of the brake pedal is smaller than the set reference travel distance value, the first and second cut valves are opened (S21), the third cut valve is closed (S22), and the braking operation is released (S10). In step S23, and if the braking lamp is turned off in the step S50, comparing the pressure of the master cylinder with the set reference pressure in step S51, and if the pressure of the master cylinder is large in step S51, The control method of the electro-hydraulic braking device, characterized in that to perform a braking operation (S60), if it is small, go to step (S21). The method of claim 3, Each of the first and second cut valves are normally open, and the third cut valve is normally closed.