KR102258682B1 - Method for controlling an electronic brake force distribution system - Google Patents

Abstract

The present invention relates to a control method of an electronic brake force distribution system, wherein the controller of the EBD (Electronic Brake Force Distribution) determines whether there is a pressure difference between the rear left/right wheel pressure and the master cylinder (MC) pressure when the EBD pulse up section starts. In the determining step, and according to the result of the determination (S102), if there is a pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure, the control unit performs time difference increase pressure control for the left/right wheel pressure of the rear wheel. Includes steps.

Description

Control method of electronic braking force distribution system {METHOD FOR CONTROLLING AN ELECTRONIC BRAKE FORCE DISTRIBUTION SYSTEM}

The present invention relates to a control method of an electronic braking force distribution system, and more specifically, the brake pedal is turned off by minimizing the pressure change of the master cylinder by adjusting the pressure increase timing of each wheel when controlling the wheel pressure pulse up after controlling the rear wheel EBD of the vehicle. The present invention relates to a control method of an electronic braking force distribution system that minimizes the occurrence of phenomena and prevents pedal heterogeneity.

In general, EBD (Electronic Brake Force Distribution) system (i.e., electronic braking force distribution system) refers to an electronic braking force distribution system that enables stable braking performance by automatically distributing appropriate braking force to the front and rear wheels according to the number of passengers or load. do.

On the other hand, the braking system of a passenger vehicle generally generates hydraulic pressure when a booster amplifies the pedal effort of the brake pedal (pneumatically) and presses the piston of the master cylinder. It is configured to brake the vehicle by rubbing the pads.

In addition, ABS-applied vehicles use the hydraulic pressure of the master cylinder (that is, a hydraulic cylinder that converts the mechanical force generated when the brake pedal is pressed into hydraulic force, and enables the brake lining to be operated with a small force). A hydraulic unit that distributes to the brakes of the wheels, a wheel speed sensor that senses the speed of each wheel, and an ABS ECU that communicates with the wheel speed sensor and controls the hydraulic unit.

In addition, the EBD system is equipped with an anti-lock brake system (ABS) instead of a conventional fixed proportional hydraulic valve, and is a safety device to improve the performance and safety of the ABS. After detecting the difference in wheel speed, the optimum braking force is distributed to the rear wheel through an actuator of ABS.

At this time, after EBD control, EBD pulse-up control is performed to increase the pressure of the two rear wheels to the master cylinder pressure. However, since the EBD Pulse-Up operates on both wheels at the same time when the vehicle is stopped and the driver continuously applies the brake, the moment the pressure of the two wheels rises, the pedal is "dumped" and the pedal is turned off ( 1).

However, the above phenomenon is caused by a sudden change in the amount of brake fluid in the master cylinder by suddenly opening the two wheel IV (Inlet Valve) valves (i.e., inlet valves) of the rear wheel when the driver is holding the brake pedal. . That is, as shown in FIG. 1, in the "EBD Pulse-Up section", a phenomenon in which the left rear wheel (RL) wheel and the right rear wheel (RR) wheel are simultaneously increased in pressure occurs. As described above, conventionally, when the EBD pulse-up is performed after EBD control, the IV valves of the two rear wheels are simultaneously opened, thereby causing a sudden change in flow rate in the master cylinder, causing the brake pedal to be turned off.

As described above, noise is generated in the EBD pulse-up section after EBD control, and the pedal is turned off, there is a problem that may cause discomfort and anxiety to the driver.

The background technology of the present invention is disclosed in Korean Patent Application Laid-Open No. 10-2012-0053212 (published on May 25, 2012, a control method of an EBD system).

The present invention was created to solve the above problems, and the brake pedal is turned off by minimizing the pressure change of the master cylinder by adjusting the timing of increasing pressure of each wheel when controlling the wheel pressure pulse up after controlling the rear wheel EBD of the vehicle. It is an object of the present invention to provide a control method of an electronic braking force distribution system that minimizes the pressure and prevents pedal discomfort.

In the control method of the electronic brake force distribution system according to an aspect of the present invention, when the EBD pulse up section starts, the control unit of the Electronic Brake Force Distribution (EBD) is the pressure between the left/right wheel pressure of the rear wheel and the pressure of the master cylinder (MC). Determining whether there is a difference; And if there is a pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure according to the result of the determination (S102), the control unit performing a time difference increasing pressure control for the left/right wheel pressure of the rear wheel. Characterized in that.

In the present invention, in the step of performing the time difference increasing pressure control, the control unit includes: determining whether a pressure difference for maintaining the left and right wheels of the rear wheel occurs; According to the determination result, when the pressure difference between the rear left and right wheels does not occur, the pulse-up pressure control is started with respect to any one of the rear left and right wheels, and the other wheel at a predetermined point in time. It is characterized in that the pulse-up pressure increase control is performed.

In the present invention, in the step of performing the time difference increasing pressure control, the control unit includes: determining whether a pressure difference for maintaining the left and right wheels of the rear wheel occurs; According to the determination result, when a pressure difference for maintaining the left and right wheels of the rear wheel occurs, pulse-up pressure control is first started with respect to the wheel with the lower pressure, and pulse-up pressure control is performed with respect to the other wheel at a predetermined point in time. It is characterized in that to perform.

In the present invention, the interval between the boosting time for the two left and right rear wheels is variable according to the EBD braking effort of the driver.

In the present invention, the specific point in time is a point in time when the pressure of the first wheel passes 50% of the target pressure increase amount after starting the pulse-up pressure on the first wheel.

In the present invention, after the step of performing time difference increase control for the rear wheel left/right wheel pressure, the controller performs EBD pulse up control when each pressure of the left/right wheel reaches the pressure of the master cylinder MC. It characterized in that it further comprises; terminating step.

In the present invention, when controlling the pulse-up pressure to increase the wheel pressure, the pressure increase slope is limited to 50 bar/sec.

In the present invention, when controlling the pulse-up pressure to increase the wheel pressure, the pressure increase is performed by opening an IV (Inlet Valve) valve.

In the present invention, the opening of the IV (Inlet Valve) valve is characterized in that it is controlled by a PWM (Pulse Width Modulation) method.

In the present invention, in the EBD pulse up section, a pressure difference occurs between the rear wheel pressure and the master cylinder pressure, and when the EBD control is terminated, the EBD pulse up control is performed to gradually increase the rear wheel pressure in order to resolve the pressure difference. It is characterized in that it is a section.

The present invention minimizes the occurrence of a brake pedal off phenomenon and prevents pedal heterogeneity by minimizing the pressure change of the master cylinder by controlling the timing of increasing the pressure of the left and right wheels of the rear wheel when controlling the wheel pressure pulse up after controlling the rear wheel EBD of the vehicle. To be able to do it.

1 is an exemplary view for explaining a change in pressure of a rear wheel that causes a pedal off phenomenon in an EBD pulse up period after a conventional EBD control.
2 is an exemplary view for explaining a method of increasing the pressure of the rear wheel in a time difference in the EBD pulse up section after EBD control when the holding pressures of the left and right rear wheels are the same according to an embodiment of the present invention.
3 is an exemplary view for explaining a method of increasing the pressure of the rear wheel with a time difference in the EBD pulse up section after EBD control when the holding pressures of the left and right rear wheels are different according to an embodiment of the present invention.
4 is an exemplary view for explaining a method of determining a pulse-up pressure point of the other wheel after first pulse-up increasing pressure on one wheel of the rear wheel in FIGS. 2 and 3.
5 is a flowchart illustrating a control method of an electronic braking force distribution system according to an embodiment of the present invention.

Hereinafter, an embodiment of a method for controlling an electronic braking force distribution system according to the present invention will be described with reference to the accompanying drawings.

In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

As described above, in the conventional EBD control by the driver's braking in a driving vehicle, when the driver's braking effort is high, wheel slip occurs in the rear wheels, and in order to prevent the increase in wheel slip, the EBD system adjusts the rear wheel pressure by using the IV valve. It is held by using.

At this time, a pressure difference occurs between the pressure of the rear wheel and the pressure of the master cylinder, and when the EBD control is terminated, the pressure of the rear wheel is gradually increased to resolve the pressure difference. The control to increase the pressure of the rear wheel after the end of the EBD is the EBD pulse-up control.

However, in order to make the pressure of the rear wheel (RL, RR) held for the EBD control the same pressure as that of the relatively high master cylinder, the IV valve must be gradually opened. There is a problem in that the brake pedal is turned off as the brake flow rate of the master cylinder enters the wheel.

Therefore, in the present embodiment, when the pulse-up after the EBD pressure is maintained, the IV valve for increasing the pressure of the rear wheel is provided with a time difference between the left and right wheel openings to prevent a sudden change in the flow rate of the hydraulic pressure of the master cylinder.

FIG. 2 is an exemplary diagram for explaining a method of increasing the pressure of the rear wheel in a time difference in the EBD pulse up section after EBD control when the holding pressures of the left and right rear wheels are the same according to an embodiment of the present invention.

As shown in Figure 2, the control unit (not shown) of the EBD system according to the present embodiment, when the holding pressure of the rear left / right wheel is the same, the rear left (RL) wheel (or the rear right (RR) wheel) First of all, open the IV valve.

As described above, if the holding pressures of the rear left and right wheels are the same, the same effect is generated even if the holding pressure of any wheel is increased first, so the control effect is the same.

3 is an exemplary view illustrating a method of increasing the pressure of the rear wheel in a time difference in the EBD pulse up section after EBD control when the holding pressures of the left and right rear wheels are different according to an embodiment of the present invention.

As shown in Figure 3, the control unit (not shown) of the EBD system according to the present embodiment, when the holding pressure of the rear left and right wheels are different from each other, the lower left rear wheel (RL) wheel (if the right rear wheel ( RR) If the pressure of the wheel is lower, first open the IV valve of the rear right (RR) wheel).

As shown in Fig. 3, when the EBD control is intervened, the two rear wheels are simultaneously generated at the moment of intervention. Therefore, the holding pressure is the same at the beginning of EBD. However, even while maintaining the same pressure, if more slip occurs on either wheel due to the difference in road conditions, only that wheel is subjected to EBD decompression to prevent the increase in slip.

Therefore, in this case, a difference occurs in the EBD holding pressure of the left and right rear wheels.

When there is a difference in the holding pressure of the left and right wheels of the rear wheel, the controller first performs the wheel with the lower pressure when opening the rear IV valve for controlling the EBD pulse-up pressure increase.

As described above, the reason for increasing the pressure of the rear wheel on the lower side first is to reduce the difference in wheel pressure on the left and right, and also to shorten the total EBD pulse-up time by increasing the low wheel pressure first. Because it can.

4 is an exemplary view illustrating a method of determining a pulse-up pressure timing of the other wheel after first pulse-up increasing pressure on one wheel of the rear wheel in FIGS. 2 and 3.

As shown in FIG. 4, the control unit (not shown) first calculates a target pressure increase amount of a wheel having a low EBD holding pressure. The target increase in pressure is the difference between the driver's foot pressure (master cylinder pressure) and the holding wheel pressure.

Next, the control unit (not shown) indicates the start point of the pulse-up pressure of the second wheel. When the first wheel starts to increase the pulse-up pressure and passes a point of 50% of the target pressure increase amount, the second wheel Implement pulse-up pressure.

Therefore, the pressure increase interval between the two wheels depends on the driver's EBD braking effort.

In addition, the increase in pressure gradient that increases the wheel pressure is limited to 50 bar/sec, thereby minimizing the increase in wheel pressure.

At this time, in order to make the increase in pressure of the low slope, the controller (not shown) may control the IV valve in a PWM method.

5 is a flowchart illustrating a control method of an electronic braking force distribution system according to an embodiment of the present invention.

As shown in FIG. 5, when the EBD pulse up section starts after the EBD control section ends (S101), the controller (not shown) determines whether there is a pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure. It is determined (S102).

According to the result of the determination (S102), if there is no pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure (No in S102), the control unit terminates the EBD control (S110). However, if there is a pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure (YES in S102), the control unit starts the EBD pulse up control (S103).

In the present embodiment, the EBD pulse up control performed when there is a pressure difference between the left/right wheel pressure of the rear wheel and the pressure of the master cylinder MC means that the time difference increase control for the left/right wheel pressure of the rear wheel is performed.

Therefore, when the EBD pulse-up control starts, the controller (not shown) determines whether a difference in pressure for maintaining the left and right wheels of the rear wheel occurs (S104).

As a result of the determination (S104), when the rear left/right wheel holding pressure difference does not occur (No in S104), the control unit (not shown) is applied to any one of the rear left/right wheels (RL wheel or RR wheel). On the other hand, pulse-up pressure increase control is started (S105).

For convenience, in this embodiment, it is assumed that the pulse-up pressure increase control is first started with respect to the RL wheel.

In addition, as a result of the determination (S104), when a difference in pressure for maintaining the left and right wheels of the rear wheel occurs (example of S104), the control unit (not shown) starts the pulse-up pressure increase control for the wheel with the lower pressure (S106). .

The control unit (not shown), after the first wheel (e.g., the wheel with the lower pressure or the RL wheel) starts to increase the pulse-up pressure, when the pressure of the first wheel passes 50% of the target pressure increase amount Pulse-up boosting of the second wheel is performed.

Therefore, when the pulse-up pressure control is started for any one of the rear left/right wheels (eg, the lower pressure wheel or the RL wheel) as described above, the controller (not shown) is the first wheel It is checked whether the pressure of reaches 50% of the target increase in pressure (S107). The check is continued until the pressure of the first wheel reaches 50% of the target increase in pressure.

Thereafter, when the pressure of the first wheel reaches 50% of the target pressure increase amount, the control unit (not shown) starts pulse-up pressure increase control for the second wheel (S108).

Then, the controller (not shown) ends the EBD pulse up control when the pressure of the second wheel reaches the pressure of the master cylinder MC (ie, equals the pressure of the master cylinder) (S109).

When all of the EBD pulse up control for the left and right rear wheels is terminated as described above, the control unit (not shown) terminates the EBD control (S110).

As described above, in this embodiment, after controlling the rear wheel EBD of the vehicle, the brake pedal is turned off by minimizing the pressure change of the master cylinder by adjusting the pressure increase timing of the left and right wheels of the rear wheel during pulse-up control of the wheel pressure. To minimize and prevent pedal discomfort.

As described above, the present invention has been described with reference to the embodiments shown in the drawings, but this is only an example, and various modifications and other equivalent embodiments are possible from those of ordinary skill in the field to which the technology pertains. I will understand the point. Therefore, the technical protection scope of the present invention should be determined by the following claims.

SECTION 1: EBD control section
SECTION 2: EBD pulse up section
SECTION 3: Time difference intensification section

Claims (10)

When the EBD pulse up section starts, the control unit of the EBD (Electronic Brake Force Distribution) determines whether there is a pressure difference between the left/right wheel pressure of the rear wheel and the pressure of the master cylinder (MC); And
According to the result of the determination (S102), if there is a pressure difference between the left/right rear wheel pressure and the master cylinder (MC) pressure, the control unit performing time difference increase pressure control for the left/right wheel pressure of the rear wheel; ,
In the step of performing the time difference increase pressure control,
The control unit,
The step of determining whether a pressure difference for maintaining the left and right wheels of the rear wheel occurs; further comprising,
According to the determination result, when a pressure difference for maintaining the left and right wheels of the rear wheel occurs, pulse-up pressure control is first started with respect to the wheel with the lower pressure, and pulse-up pressure control is performed with respect to the other wheel at a predetermined point in time. Control method of an electronic braking force distribution system, characterized in that to perform.
The method of claim 1, wherein the control unit,
In the step of determining whether the rear wheel left/right wheel holding pressure difference occurs,
According to the determination result, when the pressure difference between the rear left and right wheels does not occur, the pulse-up pressure control is started with respect to any one of the rear left and right wheels, and the other wheel at a predetermined point in time. Control method of an electronic braking force distribution system, characterized in that performing pulse-up pressure increase control for the.
delete The method according to claim 1 or 2,
The interval between the boosting time for the two left and right rear wheels,
Control method of an electronic braking force distribution system, characterized in that it varies according to the driver's EBD braking effort.
The method of claim 1 or 2, wherein the specific time point is,
The control method of an electronic braking force distribution system, characterized in that after starting the pulse-up pressure increase control for the first wheel, the pressure of the first wheel passes through a time point of 50% of the target pressure increase amount.
The method of claim 1,
After the step of performing time difference increase pressure control for the left/right wheel pressure of the rear wheel,
The control method further comprises: terminating the EBD pulse up pressure control when each pressure of the left/right wheel of the rear wheel reaches the pressure of the master cylinder (MC).
The method of claim 1,
When controlling the pulse-up pressure to increase the wheel pressure, the pressure increase slope is limited to 50 bar/sec.
The method of claim 1,
When controlling the pulse-up pressure to increase the wheel pressure, the pressure increase is performed by opening an IV (Inlet Valve) valve.
The method of claim 8, wherein the opening of the IV (Inlet Valve) valve,
Control method of an electronic braking force distribution system, characterized in that controlled by a PWM (Pulse Width Modulation) method.
The method of claim 1, wherein the EBD pulse up period,
An electronic braking force distribution system, characterized in that a pressure difference occurs between the rear wheel pressure and the master cylinder pressure, and when the EBD control is terminated, the EBD pulse up pressure control is performed to gradually increase the rear wheel pressure in order to resolve the pressure difference. Control method.

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