KR20090093137A - A brake system for a vehicle and the control method thereof - Google Patents

Abstract

A vehicle brake apparatus and a control method thereof are provided to increase the braking vehicle safety by performing the break booster role by operating a solenoid or motor with the battery voltage. A vehicle brake apparatus comprises a master cylinder(30), a HECU(hydraulic electric control unit), a high pressure accumulator(57), a booster valve(58), and a motor cut valve(59). The master cylinder supplies the brake pressure a brake caliper of a wheel(60). The HECU mounts a hydraulic circuit(50) and controls the brake pressure of the master cylinder. The high pressure accumulator is installed between a HSV valve(54) and an USV valve(55). The high pressure accumulator additionally supplies the fluid pressure to the wheel. The booster valve is installed between the master cylinder and the wheel. The booster valve controls the wheel inner pressure depending on the angle of a brake pedal(10). The motor cut valve is installed at the output site of a pump(53).

Description

Brake system for vehicle and its control method

The present invention relates to a brake device of a vehicle and a control method thereof, and more particularly, to a HECU connected to a master cylinder to perform a role of a booster.

1 is a block diagram of a conventional general brake system.

As shown in FIG. 1, the brake booster 20 ′ that delivers the pedaling force of the brake pedal 10 to the master cylinder 30 ′ in the brake system of the vehicle is not only bulky but also located at an important part of the vehicle, thereby providing significant spatial utilization. Falls.

Meanwhile, in the related art, the HECU 40 '(hydraulic electric control unit) connected to the master cylinder 30' includes logics such as ESC (Electronic Stability Control), TCS (Traction Control System) and ABS (Anti-lock Brake System). It works only under control, most of the time it waits and does nothing.

In this way, the HECU does not perform any operation as compared to performing other control in the waiting time, it can be seen that the utilization of the component is less.

For reference, the average running time of HECU, including ESC, TCS, and ABS, from the vehicle's release to the abandoned car, is about 20 hours.

For example, if the vehicle's service life is 10 years, the HECU's usage rate is 0.0228%, which is only used for a limited time.

10 years / 20 hours = 87,600 hours / 20 hours = 0.000228 = 0.0228%

The present invention has been made in view of the conventional situation as described above, the purpose is to eliminate the bulky brake booster to increase the space utilization of the vehicle, as well as to contribute to cost reduction, low frequency of use The present invention provides a brake device for a vehicle and a control method thereof, which can improve the utilization of the HECU and enable the brake to be operated only by the voltage of the battery without the engine negative pressure.

The present invention is characterized in that to remove the existing brake booster to achieve the above object and to utilize the HECU as a brake booster during the waiting time of the HECU.

In other words, the HECU is equipped with a hydraulic circuit that can generate a high pressure by itself, by adding two solenoid valves and one accumulator to the hydraulic circuit can act as a brake booster.

The brake device of the vehicle of the present invention is to directly connect the master cylinder for transmitting the braking pressure to the brake caliper through a connecting rod to the brake pedal, and to control the braking pressure of the master cylinder through the HECU equipped with a hydraulic circuit.

HECU hydraulic circuit in the present invention is installed between the HSV valve and the USV valve booster substitute high-pressure accumulator for supplying the hydraulic pressure to the wheel in addition to the hydraulic supply of the master cylinder; A booster valve (BSTV) installed between the master cylinder and the wheel and controlled by PWM to control the pressure inside the wheel with respect to the angle of the brake pedal; And a motor cut valve (MTCV) installed at the output side of the pump to block the fluid supply to the wheel when the high pressure is stored in the high pressure accumulator.

In the present invention, when the driver presses the brake pedal, the brake pedal angle is sensed to calculate the target hydraulic pressure of the master cylinder pressure Pm and the hydraulic unit internal pressure Pa, and the booster valve is PWM-controlled to adjust Pm to the target pressure. It controls the USV valve and motor cut valve by PWM control and discharges the high pressure accumulator fluid to the target pressure by Pa to increase the pressure between Pm and Pa according to the target pressure.

When the target wheel pressure is higher than the pressure of the high pressure accumulator, the HSV valve is opened and the pump is turned on, and the fluid located at the pump inlet is forced through the HSV valve in the direction of the wheel to increase the braking pressure of the wheel.

On the other hand, when the driver releases the brake pedal and reduces the brake pedal angle, the driver's brake pedal input value is sensed to calculate the target hydraulic pressure of the master cylinder pressure (Pm) and the hydraulic unit internal pressure (Pa), and the booster valve is PWM controlled. By controlling the Pm to the target pressure, PWM control the USV valve and motor cut valve to inject the fluid from the wheel into the high pressure accumulator so that Pa meets the target pressure, and reduce the pressure of Pm and Pa to the target pressure.

When the pressure of the wheel is higher than the pressure of the high pressure accumulator, the motor cut valve cross, the AV valve open, the HSV valve cross, the USV valve open, the pump are turned on, and the fluid flowing through the AV valve and located at the pump inlet is forced to the high pressure accumulator. Reduce the pressure of Pm and Pa to the target pressure.

According to the present invention, since it is possible to remove the existing brake booster, it is possible not only to greatly improve the space utilization of the vehicle, but also to reduce the cost, and to greatly increase the utilization of parts of the HECU, which has a very low frequency of use. It becomes possible.

In addition, since the engine is exhausted and no engine pressure is used, the negative pressure is not used. Therefore, it is possible to drive the solenoid and the motor using only the battery voltage to act as a brake booster, thereby improving the braking safety of the vehicle.

1 is a block diagram of a conventional general brake system

2 is a block diagram of an embodiment of the present invention

3 is a HECU hydraulic circuit diagram of the embodiment;

Figure 4 is a schematic diagram for analyzing the difference between the existing master cylinder and the present invention master cylinder

5 is a control graph of the master cylinder pressure Pm and the hydraulic unit internal pressure Pa of the present invention.

6 is a hydraulic mode flow chart of the present invention.

Figure 7a is a fluid transfer state in the first boost mode of the present invention

Figure 7b is a fluid transfer state in the second boost mode of the present invention

Figure 7c is a fluid transfer state in the first pressure reduction mode of the present invention

Figure 7d is a fluid transfer state in the second decompression mode of the present invention

Fig. 8A is a control flowchart in the first boost mode of the present invention.

8B is a control flowchart in the second boost mode of the present invention.

8C is a control flowchart in the first decompression mode of the present invention.

8D is a control flowchart in the second decompression mode of the present invention.

<Explanation of Signs of Major Parts of Drawings>

10: air tank 11: connecting rod

30: master cylinder 40: HECU

50: hydraulic circuit 51: EV valve

52: AV valve 53: pump

54: HSV valve 55: USV valve

56: accumulator 57: high pressure accumulator

58: booster valve (BSTV) 59: motor cut valve (MTCV)

60: wheel 61: caliper

Hereinafter, the specific technical details of the present invention will be described in more detail with reference to the accompanying drawings.

2 is a block diagram of one embodiment of the present invention, and FIG. 3 is a HECU hydraulic circuit diagram of the embodiment.

As shown in FIG. 2, the brake device of the vehicle of the present invention directly connects the master cylinder 30 for supplying a braking pressure to the brake caliper of the wheel 60 through the connecting rod 11 to the brake pedal 10, and the hydraulic circuit. It is to control the braking pressure of the master cylinder 30 through the HECU (40) mounted.

In the present invention, the HECU hydraulic circuit 50 is provided with the EV valve 51 and the AV valve 52 in the caliper 61 of the wheel 60 to which the hydraulic pressure of the master cylinder 30 is transmitted as shown in FIG. The HSV valve 54 and the USV valve 55 are installed on the input side and the output side of the pump 53 connected to the AV valve 52, and the accumulator 56 is provided between the AV valve 52 and the pump 53. In the HECU hydraulic circuit 50 is installed,

A booster substitute high pressure accumulator 57 installed between the HSV valve 54 and the USV valve 55 to supply hydraulic pressure to the wheel 60 together with the hydraulic supply of the master cylinder 30;

A booster valve 58 (BSTV) installed between the master cylinder 30 and the wheel 60 and controlled by PWM to control the pressure inside the wheel 60 with respect to the angle of the brake pedal 10;

It is provided on the output side of the pump 53, the motor cut valve 59 (MTCV) to block the fluid supply to the wheel 60 when storing the high pressure in the high pressure accumulator 57;

On the input side and the output side of the booster valve 58, a pressure sensor P1 for measuring the master cylinder pressure Pm and a pressure sensor P2 for measuring the internal pressure Pa of the hydraulic unit are installed. Will be.

Figure 4 is a schematic diagram for analyzing the difference between the existing master cylinder and the present master cylinder.

As shown in FIG. 4, the master cylinder of the present invention has a smaller diameter than the existing master cylinder, and the force (F) acting on each master cylinder can be expressed as a product of pressure and cross-sectional area.

* F (force) = P (pressure) × A (cross-section)

Therefore, the conventional master cylinder has a low cross-sectional area, but the pressure is low, but can supply a large amount of fluid, while the master cylinder of the present invention has a high cross-sectional area, but the pressure is high, but it is difficult to supply a lot of fluid.

However, when the fluid is additionally supplied to the master cylinder of the present invention, the same function as that of the existing master cylinder can be realized. In the present invention, the additional fluid is supplied through the HECU.

On the other hand, during brake operation, the input is the angle of the brake pedal and the output is the caliper pressure.

① Brake Pedal Angle 압력 Pressure of Caliper * Ratio Constant

② Brake Pedal Angle 압력 Pressure Map of Caliper

If the above ① or ② conditions are used, the performance can be similar to that of the conventional brake system.

When the driver presses the pedal during brake operation, the flow rate is small, but if the HECU supplies pressure to the caliper for the control of ① or ② above, the caliper can generate a pressure similar to that of the existing brake system, allowing the brake to be operated. Boost mode)

When the driver releases the brake when the brake is released, the discharged flow rate is small, but if the flow rate is discharged from the caliper for the control of ① or ② in the HECU, a pressure similar to that of the existing brake system may be generated to release the brake (decompression mode).

In the case of a master cylinder without generating negative pressure, the master cylinder pressure (Pm) is greater than that of the master cylinder without generating negative pressure of the existing system.

In addition, the master cylinder pressure (Pm) is less than the internal pressure of the hydraulic unit (Pa) to obtain the braking force of the vehicle, so that the brake pedal will not be stepped on even if the brake pedal is pressed anymore.

When the cylinder diameter is reduced without the booster as in the present invention, when the brake pedal is pressed on the master cylinder having a small cross-sectional area, high pressure is generated and the supply amount of the fluid is reduced, but when the supply amount of the fluid is increased, normal brake operation can be performed.

At this time, the supply pressure of the fluid can be monitored through the master cylinder pressure (Pm) and the internal pressure of the hydraulic unit (Pa) to obtain braking force, and control the pump and each solenoid (controllable).

That is, in the present invention, the master cylinder pressure Pm and the hydraulic unit internal pressure Pa are controlled in the form as shown in FIG.

[Section A]

① When you press the brake pedal, the pressure rises rapidly in the small volume. ② The brake pedal angle increases, so the target pressure rises, and the internal fluid flows accordingly.

[Section B]

③ When the master cylinder pressure (Pm) rises and exceeds the dress hold, the booster valve (BSTV) is opened and the pressure drops. ④ When the booster valve (BSTV) is opened, the master cylinder pressure (Pm) flows into the wheel. The pressure rises.

In the present invention, when the power supply is not supplied, the booster valve 58 (BSTV) and the EV valve 51 are opened, and the AV valve 52, the motor cut valve 59 (MTCV), the USV valve 55, and the HSV valve ( 54) is closed.

When the driver presses the brake pedal 10, the fluid is supplied in the order of the master cylinder 30-the booster valve 58 (BSTV)-the EV valve 51-the caliper 61 and brakes the wheel 60 at low pressure. Pressure can be supplied.

6 shows a hydraulic mode flow chart of the present invention.

In the present invention, when the wheel pressure Pw is less than the high pressure accumulator pressure Pacc during operation of the brake, only the solenoid is driven (increase pressure 1), and when the wheel pressure Pw is greater than the high pressure accumulator pressure Pacc, the motor together with the solenoid Is driven (pressure boost 2).

When the brake is released, only the solenoid is driven (decompression 1) when the wheel pressure Pw is less than the high pressure accumulator pressure Pacc. When the wheel pressure Pw is greater than the high pressure accumulator pressure Pacc, the motor is driven together with the solenoid. (Decompression 2).

Of course, each mode change proceeds when the dress hold is exceeded.

Meanwhile, in the present invention, the high pressure accumulator 57 must be filled with a predetermined initial pressure (for example, 50 bar), and fluid must be present in the HECU 40 in addition to the fluid supplied from the driver's force when the driver's brake pedal is operated. The fluid supply may increase the braking pressure of the wheel 60.

The fluid for filling the high pressure accumulator 57 is connected to the high pressure via the path of the booster valve 58 (BSTV)-EV valve 51-AV valve 52-pump 53-pump-USV valve 55 in the reservoir. It flows into the accumulator 57.

In the present invention, the high pressure fluid filled in the high pressure accumulator 57 is opened by the USV valve 55 and the motor cut valve 59 (MTCV). The USV valve 55-the motor cut valve 59-the EV valve 51 It is possible to apply a braking pressure to the wheel 60 by way of the caliper 61.

In addition, when the pressure of the high pressure accumulator 57 is low, the fluid of the high pressure accumulator 57 is forcibly pumped, and the HSV valve 54-pump 53-pump-motor cut valve 59 (MTCV)-EV valve 51 It is possible to increase the braking pressure of the wheel 60 in the path of the caliper (61).

On the other hand, when the braking pressure of the wheel 60 is high, the caliper 61-EV valve 51-Motor cut valve 59 (MTCV)-USV valve are opened by opening the motor cut valve 59 (MTCV) and the USV valve 55. (55)-When the pressure of the high pressure accumulator 57 can be reduced, and the pressure of the high pressure accumulator 57 is high, the AV valve 52 and the USV valve 55 are opened to open the caliper 61-AV. Forced pressure reduction can be performed by the path of the valve 52-pump 53-USV valve 55-high-pressure accumulator 57.

That is, FIG. 7A shows a fluid transfer state diagram in the first boost mode of the present invention, and FIG. 8A shows a control flowchart in the first boost mode.

In the present invention, when the driver presses the brake pedal in a state in which the braking pressure of the wheel 60 is smaller than the pressure of the high pressure accumulator 57, the brake pedal angle is sensed to sense the master cylinder pressure Pm and the hydraulic unit internal pressure Pa. Calculate the target hydraulic pressure of Pm> Pa during the initial driver brake pedal pressurization, PWM control booster valve 58 to adjust Pm to target pressure, USV valve 55 and motor cut valve 59 PWM By controlling, the fluid of the high pressure accumulator 57 is discharged to the wheel 60 so that Pa matches the target pressure.

Then, the pressures of Pm and Pa are increased and pressurized to the target pressure so that the target pressures are similar to Pm and Pa.

FIG. 7B shows a fluid transfer state diagram in the second boost mode of the present invention, and FIG. 8B shows a control flow chart in the second boost mode.

On the other hand, if the braking pressure of the wheel 60 is greater than the pressure of the high-pressure accumulator 57 during the braking process, Pm> Pa during the initial driver brake pedal pressurization, so that the booster valve 58 is PWM controlled to control Pm to the target pressure. When the target wheel pressure is higher than the pressure of the high-pressure accumulator 57, the HSV valve 54 is opened, the pump 53 is turned on, and the fluid located at the pump inlet through the HSV valve 54 is forcibly discharged in the direction of the wheel. The braking pressure of the wheel 60 is increased.

Then, the pressures of Pm and Pa are increased and pressurized to the target pressure so that the target pressures are similar to Pm and Pa.

 That is, FIG. 7C shows a fluid transfer state diagram in the first decompression mode of the present invention, and FIG. 8C shows a control flowchart in the first decompression mode of the present invention.

In the present invention, when the driver releases the brake pedal to reduce the brake pedal angle while the braking pressure of the wheel 60 is greater than the pressure of the high pressure accumulator 57, the driver brake pedal input value is sensed to sense the master cylinder pressure ( Calculate the target hydraulic pressure of Pm) and the hydraulic unit internal pressure (Pa), and control the Pm to the target pressure by PWM control the booster valve (58) because Pm> Pa during decompression, and the USV valve (55) and the motor cut. PWM control of the valve 59 flows the fluid of the wheel 60 into the high pressure accumulator 57 so that Pa may match the target pressure.

Then, the pressures of Pm and Pa are reduced to match the target pressure so that the target pressures are similar to Pm and Pa.

FIG. 7D shows a fluid transfer state diagram in the second decompression mode of the present invention, and FIG. 8D shows a control flowchart in the second decompression mode of the present invention.

On the other hand, if the braking pressure of the wheel 60 is lower than the pressure of the high-pressure accumulator 57 during the depressurization process, Pm> Pa during decompression, so that the booster valve 58 is PWM controlled to control Pm to the target pressure. Is higher than the pressure of the high pressure accumulator 57, the motor cut valve 59 close, the AV valve 52 open, the HSV valve 54 close, the USV valve open, the pump 53 are turned on, and the AV valve ( When the fluid flowing through the pump inlet 52 is forcibly pumped to the high pressure accumulator 57, the motor cut valve 59 is closed and the USV valve 55 is opened, thereby causing pressure on the high pressure accumulator 57.

Then, the pressures of Pm and Pa are reduced to match the target pressure so that the target pressures are similar to Pm and Pa.

Claims (7)

A HECU 40 having a hydraulic circuit 50 mounted thereon by directly connecting a master cylinder 30 for supplying a braking pressure to the brake caliper 61 of the wheel 60 via a connecting rod 11 to the brake pedal 10. Brake device of the vehicle, characterized in that for controlling the braking pressure of the master cylinder (30). The HECU hydraulic circuit 50 is provided with an EV valve 51 and an AV valve 52 in the caliper 61 of the wheel 60 to which the hydraulic pressure of the master cylinder 30 is transmitted. HSV valve 54 and USV valve 55 are installed on the input side and output side of pump 53 connected to 52, and accumulator 56 is installed between AV valve 52 and pump 53. , A booster substitute high pressure accumulator 57 installed between the HSV valve 54 and the USV valve 55 to supply hydraulic pressure to the wheel 60 together with the hydraulic supply of the master cylinder 30; A booster valve 58 (BSTV) installed between the master cylinder 30 and the wheel 60 and controlled by PWM to control the pressure inside the wheel 60 with respect to the angle of the brake pedal 10; The motor cut valve 59 (MTCV) is installed on the output side of the pump 53 and shuts off the fluid supply to the wheel 60 when storing the high pressure in the high pressure accumulator 57. Brake device. The pressure sensor P1 for measuring the master cylinder pressure Pm at the input side and the output side of the booster valve 58, and a pressure sensor for measuring the internal pressure Pa of the hydraulic unit. A brake device for a vehicle, wherein P2) is provided. A HECU 40 having a hydraulic circuit 50 mounted thereon by directly connecting a master cylinder 30 for supplying a braking pressure to the brake caliper 61 of the wheel 60 via a connecting rod 11 to the brake pedal 10. Controlling the braking pressure of the master cylinder (30), The HECU hydraulic circuit 50 is provided with an EV valve 51 and an AV valve 52 in the caliper 61 of the wheel 60 to which the hydraulic pressure of the master cylinder 30 is transmitted, and is connected to the AV valve 52. The HSV valve 54 and the USV valve 55 are installed on the input side and the output side of the pump 53, and the accumulator 56 is installed between the AV valve 52 and the pump 53, and the HSV valve ( A booster substitute high pressure accumulator 57 installed between the 54 and the USV valve 55 to supply the hydraulic pressure to the wheel 60 together with the hydraulic supply of the master cylinder 30; A booster valve 58 (BSTV) installed between the master cylinder 30 and the wheel 60 and controlled by PWM to control the pressure inside the wheel 60 with respect to the angle of the brake pedal 10; Control of the brake device of the vehicle further provided with a motor cut valve 59 (MTCV) installed on the output side of the pump 53 to shut off the fluid supply to the wheel 60 when storing the high pressure in the high pressure accumulator 57 In the method, When the driver presses the brake pedal, the brake pedal angle is sensed to calculate the target hydraulic pressure of the master cylinder pressure (Pm) and the internal pressure of the hydraulic unit (Pa), and the PWM is controlled by the booster valve 58 to adjust the Pm to the target pressure. PWM control of the USV valve 55 and the motor cut valve 59 to discharge the fluid of the high-pressure accumulator 57 to the wheel 60 so that the Pa corresponds to the target pressure. The control method of the brake device of the vehicle, characterized in that for increasing the pressure. 5. The valve according to claim 4, wherein when the target wheel pressure is higher than the pressure of the high pressure accumulator 57, the HSV valve 54 is opened, the pump 53 is turned on, and the fluid located at the pump inlet through the HSV valve 54 is forcibly applied. The control method of the brake apparatus of the vehicle characterized by the above-mentioned. A HECU 40 having a hydraulic circuit 50 mounted thereon by directly connecting a master cylinder 30 for supplying a braking pressure to the brake caliper 61 of the wheel 60 via a connecting rod 11 to the brake pedal 10. Controlling the braking pressure of the master cylinder (30), The HECU hydraulic circuit 50 is provided with an EV valve 51 and an AV valve 52 in the caliper 61 of the wheel 60 to which the hydraulic pressure of the master cylinder 30 is transmitted, and is connected to the AV valve 52. The HSV valve 54 and the USV valve 55 are installed on the input side and the output side of the pump 53, and the accumulator 56 is installed between the AV valve 52 and the pump 53, and the HSV valve ( A booster substitute high pressure accumulator 57 installed between the 54 and the USV valve 55 to supply the hydraulic pressure to the wheel 60 together with the hydraulic supply of the master cylinder 30; A booster valve 58 (BSTV) installed between the master cylinder 30 and the wheel 60 and controlled by PWM to control the pressure inside the wheel 60 with respect to the angle of the brake pedal 10; Control of the brake device of the vehicle further provided with a motor cut valve 59 (MTCV) installed on the output side of the pump 53 to shut off the fluid supply to the wheel 60 when storing the high pressure in the high pressure accumulator 57 In the method, When the driver releases the brake pedal to decrease the brake pedal angle, the driver senses the driver brake pedal input value to calculate the target hydraulic pressure of the master cylinder pressure Pm and the hydraulic unit internal pressure Pa, and then boosts the booster valve 58. By controlling the PWM, Pm is controlled to the target pressure, and the USV valve 55 and the motor cut valve 59 are PWM-controlled so that the fluid of the wheel 60 flows into the high pressure accumulator 57 so that Pa is matched to the target pressure. To reduce the pressure of Pm and Pa according to the target pressure. 7. The motor cut valve 59 close, the AV valve 52 open, the HSV valve 54 close, the USV valve open, the pump when the pressure of the wheel 60 is higher than the pressure of the high pressure accumulator 57. (53) of the brake device of the vehicle, characterized in that to turn on, forcibly pumping the fluid located at the pump inlet through the AV valve 52 to the high pressure accumulator 57 to reduce the pressure of Pm and Pa to the target pressure Control method.