Vehicle brake device and control method thereof

Abstract

According to at least one embodiment, the present disclosure provides a method of controlling a brake of a vehicle, the method including the steps of determining, by a controller, a pressure difference between a passage pressure determined by hydraulic pressure of a wheel brake and a required brake pressure; opening, by the controller, a control valve when the passage pressure is greater than the required brake pressure; and controlling the control valve based on a difference between the required brake pressure and the passage pressure. The system and method of controlling a brake of a vehicle provided by the present disclosure can maintain the brake pressure of the wheel brake to be the same as the required pressure, can reduce noise generated by a piston hitting one end of a master cylinder, and can prevent damage to the piston by adjusting the control position of the piston according to the number of revolutions per minute of an engine.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0095454, filed on July 21, 2021, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to an automotive braking system and a method for controlling the automotive braking system. More specifically, this disclosure relates to an automotive control system and a method for controlling the residual pressure of a hydraulic generator. Background Technology

[0004] The descriptions in this section are for background information only and do not constitute related technology.

[0005] In automotive braking systems with hydraulic generators, residual pressure may remain in the wheel brakes even when braking pressure is not required.

[0006] For example, in an integrated braking system with Electronic Stability Control (ESC), the braking pressure of the wheel brakes is determined based on the engine speed driving the hydraulic generator. When changes in pedal pressure or other factors alter the required braking pressure for wheel braking, the engine drives the hydraulic generator to adjust the wheel brake pressure to match the required braking pressure. When the engine speed exceeds a critical speed, the volume of working fluid flowing to the wheel brakes per unit time can exceed the volume of the chamber in the hydraulic generator that increases per unit time. In this case, working fluid can flow from the reservoir into the chamber. Therefore, residual pressure can be generated at the wheel brakes.

[0007] To remove residual pressure generated at the wheel brakes, when the required braking pressure is less than the pressure applied to the wheel brakes, the automotive braking system of the relevant technology removes the residual pressure at the wheel brakes by returning the piston of the hydraulic generator to its initial position, controlling the returning piston to maintain the piston displacement, and opening a valve in the passage communicating with the wheel brakes and the reservoir.

[0008] Figure 1 A diagram illustrating the pressure and channel pressure required to implement residual pressure control when using systems and methods for controlling the brakes of a vehicle via related technologies.

[0009] See Figure 1According to relevant braking systems, when the braking pressure of the wheel brake, which is altered by the piston position and fluid flow, is equal to or less than the required pressure, it is difficult to make the braking pressure of the wheel brake the same as the required pressure. Furthermore, when the linear speed of the piston exceeds the predetermined speed, there is a possibility that the piston may generate noise and be damaged (if severe) by impacting one end of the master cylinder. Summary of the Invention

[0010] According to at least one embodiment, this disclosure provides a method for controlling a vehicle brake, the brake comprising: a reservoir for storing working fluid; a master cylinder connected to the reservoir; wheel brakes configured to supply hydraulic pressure from the master cylinder; a residual pressure control hydraulic line communicating with the reservoir and the wheel brakes; a control valve installed in the residual pressure control hydraulic line; an input unit for receiving a braking pressure required for the wheel brakes; and a controller for controlling the opening of the control valve; the method comprising: determining, by the controller, a pressure difference between a channel pressure determined by the hydraulic pressure of the wheel brakes and a required braking pressure; opening the control valve by the controller when the channel pressure is greater than the required braking pressure; and controlling the control valve based on the difference between the required braking pressure and the channel pressure.

[0011] According to at least one embodiment, this disclosure provides a system for controlling a vehicle brake, the system comprising: a reservoir for storing working fluid; a master cylinder connected to the reservoir; wheel brakes configured to supply hydraulic pressure from the master cylinder; a residual pressure control hydraulic line communicating with the reservoir and the wheel brakes; a control valve installed in the residual pressure control hydraulic line; an input unit for receiving a braking pressure required for the wheel brakes; and a controller for controlling the opening of the control valve, wherein the controller determines a pressure difference between a channel pressure determined by the hydraulic pressure of the wheel brakes and a required braking pressure, opens the control valve when the channel pressure is greater than the required braking pressure, and, after opening the control valve, controls the control valve based on the difference between the required braking pressure and the channel pressure. Attached Figure Description

[0012] Figure 1 The diagram illustrates the variation of pressure and channel pressure over time when implementing residual pressure control using systems and methods for controlling the brakes of a vehicle via related technologies.

[0013] Figure 2 A hydraulic circuit diagram showing the arrangement of a system for controlling a vehicle's brakes according to an embodiment of the present disclosure is provided.

[0014] Figure 3 A block diagram illustrating the configuration of a system for controlling the brakes of a vehicle according to an embodiment of the present disclosure is provided.

[0015] Figure 4 A flowchart illustrating a method for controlling the brakes of a vehicle according to an embodiment of the present disclosure is provided.

[0016] Figure 5 A flowchart illustrating a method for controlling the brakes of a vehicle according to another embodiment of the present disclosure is provided.

[0017] Figure 6 The diagram illustrates the variation of pressure and channel pressure over time when residual pressure control is implemented using a system and method for controlling the brakes of a vehicle according to embodiments of the present disclosure. Detailed Implementation

[0018] Therefore, a method for controlling the brakes of a vehicle according to embodiments of the present disclosure has been proposed to solve the above-mentioned problems, and is able to maintain the braking pressure of the wheel brakes the same as the required pressure by opening / closing a control valve installed in a channel connected to the brakes and the reservoir by a controller, regardless of the relationship between the required pressure and the braking pressure of the wheel brakes.

[0019] Furthermore, the method for controlling the vehicle's brakes according to embodiments of this disclosure can reduce noise generated by the piston striking one end of the master cylinder, and prevent damage to the piston by adjusting the piston's control position according to the engine's revolutions per minute (RPM).

[0020] The purpose of this disclosure is not limited to the above-described purposes, and other purposes will be clearly understood by those skilled in the art from the following description.

[0021] In the following description, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals preferably indicate the same elements, even though the elements are shown in different drawings. Furthermore, in the following description of some embodiments, for the purpose of clarity and brevity, detailed descriptions of related known components and functions will be omitted when this may obscure the subject matter of the disclosure.

[0022] Furthermore, the alphanumeric codes in the numbering components, such as first, second, i), ii), (a), (b), etc., are used only to distinguish one component from another, and do not imply or suggest the material, order, or sequence of the components. Throughout the specification, when a component "comprises" or "contains" a component, they are intended to include other components as well, without excluding other components, unless specifically described to the contrary. Terms such as "unit" and "module" refer to one or more units for performing at least one function or operation, which can be implemented by hardware, software, or a combination thereof.

[0023] See Figure 2 A system for controlling a vehicle brake according to an embodiment of the present disclosure includes some or all of the following: a reservoir 210 for storing working fluid, a master cylinder 220 connected to the reservoir 210, a wheel brake 230 configured to supply hydraulic pressure from the master cylinder 220, a residual pressure control hydraulic line 241 connected to the reservoir 210 and the wheel brake 230, a control valve 251 disposed or installed in the hydraulic line 241, an input unit 260 for receiving the braking pressure required for the wheel brake 230, and a controller 300 for controlling the opening of the control valve 251.

[0024] The reservoir 210 stores the working fluid and is in fluid communication with the cylinder of the wheel brake 230 mounted at the wheel, so that the fluid stored in the reservoir 210 is transferred to the wheel brake 230 or the working fluid returns from the wheel brake 230. The reservoir 210 can be indirectly connected to the wheel brake 230 via the master cylinder 220, multiple valves, etc. Typically, an outlet valve OV that is closed when no current is applied and an inlet valve IV that is open when no current is applied are provided at each wheel brake 230. When the wheel brake 230 is pressurized, the working fluid is transferred from the reservoir 210 to the wheel brake 230 through the inlet valve IV, thus increasing the braking pressure of the wheel brake 230. When the wheel brake 230 is depressurized, the hydraulic pressure of the working fluid is transferred from the wheel brake 230 to the reservoir 210 through the outlet valve OV, thus decreasing the braking pressure of the wheel brake 230.

[0025] The master cylinder 220 generates hydraulic pressure to transfer working fluid to the wheel brakes 230 based on a brake request signal input from the brake pedal, etc. This brake request signal can be generated by a pedal simulator capable of recognizing the driver's intention to operate the pedal and the amount of pedal stroke.

[0026] According to an embodiment of this disclosure, an engine 224 is mounted on the longitudinal side of a master cylinder 220. The torque of the engine 224 can be used to linearly move a piston 223 within the master cylinder 220 via a main shaft 226 and a retaining nut 228 fixed to the main shaft 226, which is coupled to the shaft of the engine 224 and rotates with the engine 224. The piston 223 generates hydraulic pressure in a passage 229 of the master cylinder 220 while simultaneously moving linearly within the master cylinder 220.

[0027] Discharge ports 225 and 227, connected to at least one wheel brake 230, are formed at the master cylinder 220. Discharge ports 225 and 227 are connected to the cylinder of the wheel brake 230 via channels. The aforementioned inlet valve IV can be installed in the channel connecting discharge ports 225 and 227 to the master cylinder 220. The volumes of two chambers 229 formed in the master cylinder 220 and separated by a piston 223 are changed by the movement of the piston 223. As the volume of each chamber 229 changes, the hydraulic pressure in each chamber 229 increases or decreases.

[0028] According to an embodiment of the present disclosure, the piston 223 of the master cylinder 220 is configured to generate hydraulic pressure at the wheel brake 230 when the piston 230 moves forward and backward. That is, the piston 223 is configured to transmit hydraulic pressure to the wheel brake 230 both when moving toward and away from the engine 224. For example, two discharge ports 225 and 227 connected to the wheel brake 230 may be formed at both ends of the master cylinder 220. Hereinafter, the discharge ports 225 and 227 at the engine 224 will be referred to as the first discharge port 225, and the other discharge port 225 and 227 will be referred to as the second discharge port 227.

[0029] A check valve 254 for preventing working fluid from flowing back from the master cylinder 220 to the reservoir 210 can be installed in a passage that communicates with the master cylinder 220 and the reservoir 210.

[0030] Wheel brake 230 limits the rotation of the wheel disc by supplying hydraulic pressure from master cylinder 220. In this disclosure, the wheel brake 230, driven by the pressure of the working fluid, can be a caliper brake, drum brake, etc. Wheel brake 230 is connected to reservoir 210 via outlet valve OV and to master cylinder 220 via inlet valve IV. A hydraulic circuit connected to two discharge ports 225 and 227 formed at master cylinder 220 can be formed such that the working fluid discharged separately from discharge ports 225 and 227 brakes the two wheels respectively.

[0031] like Figure 2The illustrated system for controlling the vehicle's brakes is an H-split type, simultaneously controlling the left front wheel (FL) and right front wheel (FR) and simultaneously controlling the left rear wheel (RL) and right rear wheel (RR). However, the invention is not necessarily limited to this, and the structure for distributing hydraulic pressure can be freely modified in design. Hereinafter, the passage connecting the first drain port 225, the left rear wheel, and the right rear wheel will be referred to as the first hydraulic line 243. Hereinafter, the passage connecting the second drain port 227, the left front wheel, and the right front wheel will be referred to as the second hydraulic line 245. In the system for controlling the vehicle's brakes according to an embodiment of the invention, a mixing valve 255 for distributing hydraulic pressure is installed between the first hydraulic line 243 and the second hydraulic line 245. Regardless of the direction of movement of the piston 223, the same hydraulic pressure can be transmitted through the mixing valve 255 to the multiple wheel brakes 230 mounted on the wheels.

[0032] Engine 224 rotates in response to a braking request signal, and piston 223 generates hydraulic pressure in master cylinder 220 via torque from engine 224. The generated hydraulic pressure is transmitted to each wheel brake 230 via a hydraulic circuit. The braking pressure transmitted to each wheel brake 230 can be varied by inlet valve IV and outlet valve OV mounted at each wheel brake 230. Inlet valve IV and outlet valve OV are solenoid valves, and their opening / closing is determined by whether current is applied.

[0033] Hydraulic line 241 is part of a hydraulic circuit that connects components of the braking system of this disclosure. The hydraulic circuit may be divided into several hydraulic lines 241. Multiple valves are installed in the hydraulic circuit.

[0034] The residual pressure control hydraulic line 241 is in communication with or connected to the reservoir 210 and the wheel brake 230. The term "communication" includes situations where the working fluid flows through another component (such as a valve or auxiliary master cylinder 220), as long as the working fluid can be transferred between the reservoir 210 and the wheel brake 230. Furthermore, the wheel brake 230, meaning the side of the wheel brake 230, includes all passages having the same or substantially the same pressure as the wheel brake 230. Even when the outlet valve OV is open, the residual pressure control hydraulic line 241 can be used to reduce the remaining residual pressure. Furthermore, the passages can be made shorter than those used to reduce the pressure of the wheel brake 230 through the outlet valve OV, thus increasing the residual pressure control response speed.

[0035] According to an embodiment of the present disclosure, the residual pressure control hydraulic line 241 is connected to the reservoir 210 from the first hydraulic line 243 via the control valve 251, the second valve 252, and the first valve 253. However, the system for controlling the brakes of a vehicle according to the present disclosure is not limited thereto. The residual pressure control hydraulic line 241 can be modified in other ways, as long as it is a hydraulic line 241 connected to the reservoir 210 and the wheel brake 230.

[0036] Control valve 251 is installed in residual pressure control hydraulic line 241. Whether control valve 251 is open / closed can be determined based on or according to whether current is applied, and can be configured such that the opening degree is determined according to the amount of current applied. When control valve 251 is open, working fluid that generates residual pressure at wheel brake 230 can be transmitted through wheel brake 230 to reservoir 210. Conversely, when control valve 251 is closed, hydraulic pressure at wheel brake 230 is not transmitted to reservoir 210 through residual pressure control hydraulic line 241.

[0037] See Figure 2 According to an embodiment of this disclosure, the system for controlling the brakes of a vehicle closes valves 256, 257, and 258 between a second hydraulic line 245 located away from control valve 251 and a reservoir 210, while the channel pressure is controlled by control valve 251. This is to facilitate the transmission of hydraulic pressure to the residual pressure control line.

[0038] The system for controlling a vehicle's brakes according to embodiments of this disclosure can open and close control valve 251 while controlling the residual pressure of wheel brake 230. Compared to related art systems for controlling a vehicle's brakes that only open control valve 251 while controlling residual pressure, the residual pressure can be controlled more precisely.

[0039] According to embodiments of the present disclosure, the control valve 251 can adjust its opening degree while the residual pressure of the control valve 251 is controlled. Therefore, compared to prior art systems for controlling vehicle brakes that only open the control valve 251 while controlling residual pressure, the residual pressure can be controlled more precisely.

[0040] See Figure 2 and 3The input unit 260 generates the required braking pressure for the wheel brakes 230. The input unit 260 may be a pedal simulator capable of recognizing the driver's intention to operate the brakes (i.e., the required braking pressure). The required braking pressure may be represented as an electrical signal, but this disclosure is not limited thereto, and the required braking pressure may be hydraulic pressure generated by a booster that increases the driver's pedal pressure. In another embodiment, the required braking pressure may be a value calculated by at least one module included in the autonomous vehicle, and the type of required braking pressure is not limited to the embodiments of this disclosure. The input unit transmits the generated required braking pressure to the controller.

[0041] The controller 300 receives the required braking pressure from the input unit 260. The controller 300 controls the opening degree of the control valve 251. This opening degree includes not only the valve's opening / closing ratio but also whether the valve is open or closed. The controller 300, meaning a device that functionally controls the valve, is not limited to a component physically separate from other components of the automotive braking system of this disclosure. Furthermore, the controller 300 may be an electronic control unit installed in an Electronic Stability Control (ESC) module.

[0042] The controller 300 determines the pressure difference between the channel pressure determined by the hydraulic pressure of the wheel brake 230 and the desired braking pressure. When the channel pressure is greater than the desired braking pressure, the controller 300 opens the control valve 251. The channel pressure is a value approximately the same as or determined based on the hydraulic pressure of the wheel brake 230. A system for controlling a vehicle's brakes according to another embodiment of this disclosure includes a wheel brake pressure detector 270 for detecting the channel pressure. Hereinafter, the control valve 251 is controlled based on the difference between the desired braking pressure and the channel pressure. Related art systems for controlling vehicle brakes close the control valve 251 upon termination of control after initiating residual pressure control and initially opening the control valve 251, without adjusting the opening degree of the control valve 251. However, the system for controlling a vehicle's brakes of this disclosure can continuously track the difference between the channel pressure determined by the hydraulic pressure of the wheel brake 230 and the desired braking pressure while controlling the residual pressure of the wheel brake 230. Therefore, the difference between the desired pressure and the channel pressure can be continuously reduced.

[0043] Specifically, when the channel pressure is greater than the required braking pressure, the controller 300 according to an embodiment of the present disclosure increases the opening of the control valve 251. When the channel pressure is less than the required braking pressure, the controller 300 decreases the opening of the control valve 251. Therefore, even if the relationship between the channel pressure and the required braking pressure changes, the difference between the channel pressure and the required braking pressure can be continuously reduced.

[0044] When the pressure obtained by subtracting the required braking pressure from the channel pressure meets a first predetermined condition (e.g., greater than a first critical value), the controller 300 according to an embodiment of this disclosure increases the opening of the control valve 251; and when the pressure obtained by subtracting the channel pressure from the required braking pressure meets a second predetermined condition (e.g., greater than a second critical value), the controller 300 decreases the opening of the control valve 251. The first or second critical value may be a table value obtained experimentally, taking into account valve opening / closing speeds, etc. However, this disclosure is not limited thereto and includes various embodiments, such as values ​​calculated in real-time by the controller 300 using a function. Furthermore, the first or second critical value may be the same value.

[0045] A method for controlling the brakes of a vehicle disclosed herein can be implemented by the system described above for controlling the brakes of a vehicle.

[0046] A method for controlling a vehicle brake disclosed herein includes: a reservoir 210 for storing working fluid, a master cylinder 220 connected to the reservoir 210, a wheel brake 230 configured to supply hydraulic pressure from the master cylinder 220, a residual pressure control hydraulic line 241 connected to the reservoir 210 and the wheel brake 230, a control valve 251 installed in the residual pressure control hydraulic line 241, an input unit 260 for receiving the braking pressure required for the wheel brake 230, and a controller 300 for controlling the opening degree of the control valve 251.

[0047] See Figure 4 The method for controlling the brakes of a vehicle disclosed herein includes some or all of the following: determining, by controller 300, the pressure difference between a channel pressure determined by the hydraulic pressure of the wheel brake 230 and the required braking pressure, and determining whether at least a portion of the piston 223 in the master cylinder 220 is in contact with one end or the other end of the master cylinder 220 (S410); opening control valve 251 by controller 300 when the channel pressure is greater than the required braking pressure (S420); comparing the magnitude of a first pressure obtained by subtracting the required braking pressure from the channel pressure with the magnitude of a first threshold value (S430); increasing the opening of control valve 251 when the first pressure is greater than the first threshold value (S440); comparing the magnitude of a second pressure obtained by subtracting the channel pressure from the required braking pressure with the magnitude of a second threshold value (S450); decreasing the opening of control valve 251 when the second pressure is greater than the second threshold value (S460); and determining whether the value obtained by subtracting the channel pressure from the required braking pressure that increases over time is a third threshold value or greater (S470).

[0048] In step S410, the channel pressure is the same as the pressure of the wheel brake 230, or a value determined based on the pressure of the wheel brake 230. When the channel pressure is higher than the required braking pressure and at least a portion of the piston 223 is in contact with one end or the other end of the master cylinder 220, the controller 300 determines that residual pressure has been generated at the wheel brake 230. The fact that at least a portion of the piston 223 is in contact with one end or the other end of the master cylinder 220 means that the displacement of the piston 223 is 0 when the displacement of the piston 223 is 0 at the cross-section of the engine 224 facing the master cylinder 220 or at the opposite cross-section.

[0049] In step S420, when residual pressure is determined to have occurred, the controller 300 opens the control valve 251. The control valve 251 may be located in the hydraulic line 241 connecting the wheel brake 230 to the reservoir 210. When the control valve 251 is open, hydraulic pressure from the wheel brake 230 is transferred to the reservoir 210, and the residual pressure in the wheel brake 230 decreases.

[0050] See Figure 2 and 3 During residual pressure control, hydraulic fluid can be transferred from the wheel brake 230 to the reservoir 210 sequentially via control valve 251, second valve 252, and first valve 253. However, the system for controlling the vehicle brakes disclosed herein is not limited to this. The residual pressure control hydraulic line 241 can be implemented in various other ways, as long as it is a hydraulic line 241 connected to the reservoir 210 and the wheel brake 230.

[0051] Following step S420, a step is performed to control the control valve 251 based on the difference between the desired braking pressure and the channel pressure. The channel pressure is either the same as the pressure of the wheel brake 230, or a value determined based on the pressure of the wheel brake 230. When controlling residual pressure, related art systems for controlling vehicle brakes close the control valve 251 upon termination of control after initiating control and initially opening it, without adjusting the opening degree of the control valve 251. However, the system for controlling vehicle brakes of this disclosure, while controlling the residual pressure of the wheel brake 230, is able to continuously track the difference between the channel pressure determined by the hydraulic pressure of the wheel brake 230 and the desired braking pressure. Therefore, the difference between the desired pressure and the channel pressure can be continuously reduced.

[0052] For example, the method for controlling the brakes of a vehicle according to an embodiment of this disclosure implements steps S430 to S460. After the controller 300 opens the control valve 251, when the channel pressure is greater than a first threshold value or more than the required braking pressure, the residual pressure is reduced by keeping the valve open. However, when the required braking pressure is greater than a second threshold value or more than the channel pressure, the control valve 251 is closed to prevent working fluid from being transferred from the wheel brake 230 to the reservoir 210. The first and second threshold values ​​are 0 or positive values. Hereinafter, the required braking pressure increases over time, and it is determined whether the value obtained by subtracting the channel pressure from the required braking pressure is a third threshold value or more (S470). When this condition is met, control ends; when the condition is not met, the method returns to step S430 and repeats the steps. The third threshold value may be the same as the second threshold value.

[0053] The vehicle braking system according to an embodiment of the present disclosure includes a step (S510) of determining whether the revolutions per minute (RPM) of the engine 224 is a predetermined value or less, and a step (S520) of controlling the position of the piston 223 of the master cylinder 220 by the controller 300.

[0054] The steps for controlling the position of piston 223 according to embodiments of this disclosure are based on the rotational speed of engine 224 driving piston 223. The rotational speed of engine 224 may be replaced by a value of the linear velocity of piston 223, such as the linear velocity of piston 223 or the amount of current applied to engine 224, which can be displayed or calculated.

[0055] In related automotive braking systems, the piston 223 is positioned at one end of the master cylinder 220 without considering its linear movement when controlling residual pressure. However, the method for controlling the vehicle's brakes in the related art does not consider the speed at which the piston 223 approaches the end of the master cylinder 220. Therefore, when the speed at which the piston 223 approaches the end of the master cylinder 220 is high, there is a problem that the piston 223 may generate noise or be damaged by impacting the master cylinder 220. However, when the speed of the engine 224 is a predetermined RPM or higher, that is, when the piston 223 approaches the end of the master cylinder 220 at a predetermined speed or higher, the method for controlling the vehicle's brakes according to the embodiments of this disclosure controls the piston 223 to move a predetermined distance from its current position toward the center of the master cylinder (S523). Therefore, it prevents the piston 223 from generating noise or being damaged when impacting the inner wall of the master cylinder 220. Furthermore, when the RPM of the engine 224 is a predetermined value or lower, the piston 223 is controlled to remain at its current position (S521).

[0056] Figure 1The diagram illustrates the variation of pressure and channel pressure over time when implementing residual pressure control using systems and methods for controlling the brakes of a vehicle via related technologies.

[0057] Figure 6 The diagram illustrates the variation of pressure and channel pressure over time when residual pressure control is implemented using a system and method for controlling the brakes of a vehicle according to embodiments of the present disclosure.

[0058] Compare Figures 1 to 6 As can be seen, compared with the systems and methods for controlling vehicle brakes in related technologies, the systems and methods for controlling vehicle brakes in this disclosure can implement more precise control by fitting the channel pressure to the required pressure.

[0059] Therefore, a method for controlling the brakes of a vehicle according to embodiments of the present disclosure has been proposed to solve the above-mentioned problems, and is able to maintain the braking pressure of the wheel brakes the same as the required pressure by opening / closing a control valve installed in a channel connected to the brakes and the reservoir by a controller, regardless of the relationship between the required pressure and the braking pressure of the wheel brakes.

[0060] Furthermore, the method for controlling the vehicle's brakes according to embodiments of this disclosure can reduce noise generated by the piston striking one end of the master cylinder, and prevent damage to the piston by adjusting the piston's control position according to the engine's RPM.

[0061] Although exemplary embodiments of this disclosure have been described for illustrative purposes, those skilled in the art will understand that various modifications, additions, and substitutions can be made without departing from the spirit and scope of the claimed invention. Therefore, exemplary embodiments of this disclosure have been described for the sake of brevity and clarity. The scope of the technical concept of these embodiments is not limited by the description. Therefore, those skilled in the art will understand that the scope of the claimed invention is not limited to the embodiments explicitly described above.

Claims

1. A method implemented by a controller of a vehicle's brake, the brake comprising: The method comprises: a reservoir for storing working fluid; a master cylinder connected to the reservoir; a wheel brake from which hydraulic pressure is supplied; a residual pressure control hydraulic line connected to the reservoir and the wheel brake; a control valve disposed at the residual pressure control hydraulic line; an input unit receiving the braking pressure required by the wheel brake; and a controller configured to control the opening degree of the control valve; the method includes: Determine (1) the pressure difference between the channel pressure determined based on the hydraulic pressure at the wheel brake and (2) the braking pressure required by the wheel brake; When the channel pressure exceeds the required braking pressure, the control valve is opened; and The control valve is controlled based on the difference between the required braking pressure and the channel pressure. The control valve includes: The first pressure obtained by subtracting the required braking pressure from the channel pressure is compared with a first predetermined value; and The second pressure obtained by subtracting the channel pressure from the required braking pressure is compared with a second predetermined value; and When the first pressure is greater than the first predetermined value, the opening degree of the control valve is increased; and When the second pressure is greater than the second predetermined value, the opening of the control valve is reduced.

2. The method according to claim 1, wherein, Controlling the control valve includes: When the channel pressure is greater than the required braking pressure, the opening of the control valve is increased; and When the channel pressure is less than the required braking pressure, the opening of the control valve is reduced.

3. The method according to claim 1, further comprising: Control the position of the piston in the master cylinder.

4. The method according to claim 3, wherein, Controlling the position of the piston includes: The position of the piston is controlled based on the rotational speed of the engine that drives it.

5. The method according to claim 4, wherein, Controlling the position of the piston includes: When the engine speed is equal to or less than a predetermined value, the piston is controlled to remain at its current position within the master cylinder; and When the engine speed is greater than the predetermined value, the piston is controlled to move from the current position to the center of the master cylinder by a predetermined distance.

6. The method according to claim 1, wherein, The controller is configured to open the control valve when the channel pressure is greater than the required braking pressure and at least a portion of the piston in the master cylinder is in contact with one end of the master cylinder.

7. The method according to claim 1, wherein, Controlling the control valve includes: Determine whether the required braking pressure increases over time and whether the value obtained by subtracting the channel pressure from the required braking pressure is equal to or greater than a predetermined value.

8. A system for controlling the brakes of a vehicle, the system comprising: A storage container that stores the working fluid; The main cylinder is connected to the reservoir; Wheel brakes, which receive hydraulic pressure from the master cylinder; A residual pressure control hydraulic line is connected to the reservoir and the wheel brake; A control valve is located at the residual pressure control hydraulic line; An input unit that receives the braking pressure required by the wheel brake; as well as A controller configured to control the opening degree of the control valve, wherein the controller is configured to: Determine the pressure difference between (1) the channel pressure determined by the hydraulic pressure of the wheel brake and (2) the braking pressure required by the wheel brake; When the channel pressure is greater than the required braking pressure, the control valve is opened; and After the control valve is opened, the control valve is controlled based on the difference between the required braking pressure and the channel pressure.

9. The system according to claim 8, wherein, The controller is also configured to: When the channel pressure is greater than the required braking pressure, the opening of the control valve is increased; and When the channel pressure is less than the required braking pressure, the opening of the control valve is reduced.

10. The system according to claim 8, wherein, The controller is also configured to: When the pressure obtained by subtracting the required braking pressure from the channel pressure is greater than a first predetermined value, the opening degree of the control valve is increased; and When the pressure obtained by subtracting the channel pressure from the required braking pressure is greater than a second predetermined value, the opening of the control valve is reduced.

11. The system according to claim 8, wherein: The master cylinder includes an engine and a piston configured to move within the master cylinder, and The piston is configured to transmit hydraulic pressure to the wheel brakes when moving toward and away from the engine.

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