KR20150146062A - Brake system for hybrid and electric vehicle andcontrol method thereof - Google Patents

Abstract

The present invention relates to a brake system for a hybrid and an electric vehicle and a control method thereof. The brake system for a hybrid and an electric vehicle according to the present invention comprises: a drive unit having a booster connected to a brake pedal, a master cylinder, and a storage tank filled with oil; a hydraulic supply unit having a hydraulic pump to pump the oil of the storage tank, an in-valve and an out-valve installed on a hydraulic line between the storage tank and wheel cylinders, and a pressure accumulator installed on the hydraulic line to fill the hydraulic line with oil; a detection unit to measure the pressure of the oil moving along the hydraulic line when the brake pedal operates; and a control unit to compensate for a difference between the measured pressure transferred from the detection unit and a prescribed reference pressure through oil discharge of the out-valve or oil supply of the pressure accumulator if the difference occurs. Moreover, the control method of the brake system for a hybrid and an electric vehicle having the booster connected to the brake pedal, the master cylinder, and the storage tank filled with oil comprises: a step of detecting whether the brake pedal operates when a vehicle is started; a step of driving the hydraulic pump to supply the oil of the storage tank to the wheel cylinders through the in-valve when an operation of the brake pedal is detected; a step of measuring a pressure of the oil transferred to the wheel cylinders through the hydraulic pump using the detection unit; and a step of compensating for a difference between the measured pressure transferred from the detection unit and a prescribed reference pressure through oil discharge of the out-valve or oil supply of the pressure accumulator if the difference occurs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a brake system for a hybrid vehicle and an electric vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a brake system for a hybrid vehicle and an electric vehicle, and more particularly, And more particularly, to a brake system and a control method thereof for a hybrid vehicle and an electric vehicle.

Generally, a hybrid electric vehicle is a vehicle that uses an existing engine and an electric motor together as a power source, and selectively uses the power of the engine or electric motor depending on the load and speed of the vehicle. It is a vehicle that can achieve high fuel efficiency and low pollution by switching to electric energy.

In the hybrid electric vehicle, when a deceleration or braking command is issued from the driver, the electric motor functions as a generator, and electric energy generated thereby is stored in the capacitor. Thus, while the electric motor functions as a generator, braking force is generated in the wheel. This braking is called regenerative braking.

[0003] In a conventional braking system for a hybrid electric vehicle, a hydraulic motor and a pump are driven to pump a brake fluid contained in a reservoir tank to pressurize the wheel. At this time, an outlet valve is opened to allow the brake fluid to flow, And the pressure of the wheel is increased by pumping the brake fluid from the reservoir tank. At this time, the cut valve is closed for disconnecting the flow path between the master cylinder and the wheel cylinder, and the wheel pressure controls the target wheel pressure to be controlled by using the normally open type inlet valve of the drive wheel FL.

At the same time, the inlet valve of the non-driving wheel RR is closed to prevent the wheel pressure of the non-driving wheel RR from rising, and the hydraulic circuit of the front wheel right wheel FR and the rear wheel left wheel RL, FL and the right rear wheel RR.

Such a conventional braking system for an electric hybrid vehicle is provided with an inlet valve for maintaining a boost pressure when the braking pressure of the wheel changes (rise, dump, hold) ) And an outlet valve (Outlet Valve).

However, the conventional braking system for a hybrid electric vehicle often generates boost pressure through frequent change of control mode, which may cause noise or durability of the valve, Oscillation may occur.

Prior art related to the present invention is Korean Patent Publication No. 10-2013-0052787 (May 23, 2013), which discloses a hybrid vehicle and a braking device for an electric vehicle.

It is an object of the present invention to provide a brake system of a hybrid and electric vehicle capable of preventing a vibration from occurring due to an instantaneous drop or overshoot of a boost pressure by immediately compensating for pressure change of a fluid by referring to opening information of a valve, And to provide a control method.

A brake system for a hybrid vehicle and an electric vehicle according to the present invention comprises a booster for interlocking with a brake pedal, a drive unit having a master cylinder and a storage tank filled with a fluid, a hydraulic pump for pumping fluid of the storage tank, A hydraulic pressure supply unit provided on the hydraulic line between the wheel cylinder and the wheel cylinders and having an accumulator installed on the hydraulic line for filling the fluid; And a control unit for controlling the flow rate of the fluid to be supplied to the flow rate control unit based on the difference value between the measured pressure transmitted from the sensing unit and a preset reference pressure, And a control unit for compensating for the temperature of the liquid.

Preferably, the outflow valve transfers the fluid to the storage tank or the master cylinder through a hydraulic line when discharging the fluid.

Preferably, the accumulator is filled with fluid during operation of the hydraulic pump, and the fluid is supplied to the hydraulic line between the in-valve and the wheel cylinder.

In addition, a cut valve is further provided on the hydraulic line between the master cylinder and the wheel cylinder, and the cut valve preferably blocks the flow of the fluid only when the brake pedal is operated.

In addition, it is preferable that the control unit is set to a reference pressure of a different level according to the operating radius of the brake pedal.

In addition, an operation sensor for detecting the operation of the brake pedal is electrically connected to the control unit.

According to another aspect of the present invention, there is provided a brake system control method for a hybrid vehicle and an electric vehicle including a booster interlocked with a brake pedal, a master cylinder, and a storage tank filled with a fluid, The method comprising the steps of: detecting whether the brake pedal is actuated; driving the hydraulic pump to supply the fluid of the storage tank to the wheel cylinder through the in-valve when the operation of the brake pedal is sensed; Measuring a pressure of the fluid delivered to the wheel cylinder by using a sensing unit; and when a difference between a measured pressure transmitted from the sensing unit and a predetermined reference pressure occurs, And compensating the difference value through supply control. do.

Further, in the step of feeding the fluid to the wheel cylinder through the in-line valve, when the operation of the brake pedal is sensed, it is preferable that the step further comprises blocking the connection line between the master cylinder and the wheel cylinder with the cut valve .

In addition, in the step of compensating for the difference value, when the measured pressure is higher than a predetermined reference pressure, it is preferable to transmit the pressure to the storage tank or the master cylinder via the out-valve.

In addition, in the step of compensating the difference value, when the measured pressure is lower than a predetermined reference pressure, it is preferable that the fluid stored in the accumulator is supplied onto the connection line between the in-valve and the wheel cylinder.

The present invention refers to valve opening information to promptly compensate for changes in the pressure of the fluid, thereby preventing instantaneous lowering and overshooting of the boost pressure to prevent the occurrence of vibration, and the durability of the valve It is possible to prevent the occurrence of the problem.

1 is a conceptual diagram for schematically showing a brake system of a hybrid vehicle and an electric vehicle according to a first embodiment of the present invention.
2 is a circuit diagram showing a brake system of a hybrid vehicle and an electric vehicle according to a first embodiment of the present invention.
3 is a block diagram schematically illustrating a method of controlling a brake system of a hybrid vehicle according to a second embodiment of the present invention.
4 is a flowchart illustrating a method of controlling a brake system of a hybrid vehicle and an electric vehicle according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving it will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings.

The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention.

1 is a conceptual diagram for schematically showing a brake system of a hybrid vehicle and an electric vehicle according to a first embodiment of the present invention.

2 is a circuit diagram showing a brake system of a hybrid vehicle and an electric vehicle according to a first embodiment of the present invention.

1 and 2, an electronic brake system according to a first embodiment of the present invention includes a drive unit 100, a hydraulic pressure supply unit 200, a sensing unit 300, and a control unit 400 .

First, the drive unit 100 includes a brake pedal 110, a booster 120, a master cylinder 130, and a storage tank 140 filled with a fluid.

The booster 120 serves to amplify the pressing force of the driver when the driver depresses the brake pedal 110. [

Here, the booster 120 may be equipped with a vacuum tank to prevent the negative pressure from being rapidly reduced during continuous braking.

The master cylinder 130 is composed of a cylinder body and a piston whose one end is detachably coupled to the inside of the cylinder body, and converts the mechanical force of the brake pedal 110 into hydraulic pressure.

A brake fluid reservoir 140 refers to a container for supplying fluid (oil or the like) to the master cylinder 130.

When the driver depresses the brake pedal 110, the fluid stored in the storage tank 140 is discharged to the outside by the operation of the master cylinder 130.

The hydraulic supply unit 200 supplies the fluid stored in the storage tank 140 to the wheel cylinder 20 provided on the wheel of the wheel.

To this end, the hydraulic pressure supply unit 200 includes a hydraulic pump 210, an inlet valve 220, an outlet valve 230, and an accumulator 240 .

Further, a separate opening / closing valve may be further provided in the first hydraulic line L1 of the hydraulic pressure supply unit 200.

The hydraulic pump 210 is installed on the first hydraulic line L1 so that the inlet side is connected to the storage tank 140 and the outlet side is connected to the in-line valve 220, which will be described later.

When the brake pedal 110 is operated, the hydraulic pump 210 pumps the fluid contained in the storage tank 140 and transfers the fluid to the wheel cylinders 20 of the wheel.

The hydraulic pump 210 may further include an electric motor (not shown) for transmitting driving force.

In addition, the hydraulic pump 210 may be driven using a power source charged in a capacitor (not shown) of the hybrid vehicle and the electric vehicle.

In valve 220 is installed on the first hydraulic line L1 connecting the hydraulic pump 210 and the wheel cylinders 20. [

Here, the valve 220 is opened to allow fluid to be pumped from the hydraulic pump 210 to be transmitted to the wheel cylinder 20 when the brake pedal 110 is operated.

The in-line valve 220 may be installed to open and close the wheel cylinders of the left and right wheels FL and FR installed on the front wheels of the vehicle and the wheel cylinders of the left and right wheels RL and RR of the rear wheels, respectively .

To this end, the first hydraulic line L1 is divided in the front and rear wheel directions of the vehicle and can be divided into the left and right wheels FL and FR of the front wheel and the left and right wheels RL and RR of the rear wheel.

At this time, an in-line valve 220 and an out-valve 230 to be described later may be installed on the divided lines of the first hydraulic line L1.

Thus, the first hydraulic line L1 can be connected to the wheel cylinders 20 of the front wheels and the wheel cylinders 20 of the rear wheels.

Out valve 230 is for discharging the fluid to the outside when the fluid passing through the in-valve 220 is equal to or higher than the reference pressure (difference value is generated) as shown in (1) of FIG.

That is, the out-valve 230 partially lowers the pressure of the fluid if the pressure of the fluid delivered to the wheel cylinder 20 exceeds the preset reference pressure in the control unit 400.

For this purpose, the out-valve 230 may be installed on the first hydraulic line L1 connecting the in-line valves 220 and the wheel cylinders 20 of the front and rear wheels, respectively.

The fluid that is branched out through any one of the out valves 230 may be transferred to the storage tank 140 through the third hydraulic line L3.

At the same time, the fluid that is branched out through the other of the out valves 230 may be transferred to the master cylinder 130 through the third hydraulic line L3.

In addition, the out-valve 230 may remain open when the brake pedal 110 is operated, as well as when the hydraulic pump 210 is operated.

As described above, the out-valve 230 can quickly discharge the fluid having the reference pressure beyond the open state.

Accordingly, frequent opening and closing operations of the out-valves 230 and the in-valves 220 can be reduced, thereby reducing damage, noise, and vibration of the valves.

The accumulator 240 is installed on the first hydraulic line L1 as shown in (2) of FIG. 2 and charges the fluid by the pulsation generated when the hydraulic pump 210 operates.

When the pressure of the fluid passing through the in-valve 220 is equal to or greater than a predetermined reference pressure (difference value) set in the control unit 400, which will be described later, the accumulator 240 releases the in- 220 to the first hydraulic line L1 between the wheel cylinders 20, as shown in FIG.

The accumulator 240 compensates for the pressure of the fluid through the additional input of the fluid as opposed to the out-valve 230.

A cut valve 250 may be further provided on the second hydraulic line L2 connecting the master cylinder 130 and the wheel cylinders 20 to the hydraulic pressure supply unit 200. [

One end of the second hydraulic line L2 may be connected to the master cylinder 130 and the other end may be connected to the first hydraulic line L1 connecting the valves 220 and the wheel cylinders 20 .

The cut valve 250 can block the flow of the fluid only when the brake pedal 110 is operated and form a pressure in the hydraulic line connecting the storage tank 140 and the hydraulic pump 210.

The sensing unit 300 measures the pressure of the fluid flowing along the first hydraulic line L1 when the brake pedal 110 is operated.

Here, the sensing unit 300 may use a pressure sensing sensor to sense the pressure of the fluid flowing along the first hydraulic line L1.

For example, when the pressure of the fluid flowing along the first hydraulic line L1 is out of the reference pressure preset in the control unit 400, which will be described later, the sensing unit 300 senses Signal.

The control unit 400 can control the driving of the hydraulic pump 210, the in valve 220, the out valve 230, the accumulator 240, and the cut valve 250 described above.

Here, when the operation of the brake pedal 110 is sensed, the control unit 400 calculates the difference between the measured pressure transmitted from the sensing unit 300 and the preset reference pressure.

When the measured pressure transmitted from the sensing unit 300 has a difference value smaller than a preset reference pressure range, the control unit 400 controls the flow of the fluid of the out-valve 230 or the fluid supply of the accumulator 240 To compensate for the difference.

In addition, the control unit 400 may be set to a reference pressure of a different level according to the operating radius of the brake pedal 110. [

In addition, an operation sensor (PTS: not shown) for sensing the operation of the brake pedal 110 or the pressure may be electrically connected to the control unit 400.

On the other hand, the control unit 400 includes a mode for selecting an anti-lock brake system (ABS) function for locking the wheel and an electronic stability control (ESC) function for controlling the vehicle attitude .

In addition, the control unit 400 may include a mode for selecting a TCS (Traction Control System) function for slip control.

Here, the control unit 400 includes an electronic control unit (ECU), a hydraulic control unit (HCU), and a wheel for detecting the speed of the wheel, for implementing the ABS function. Further sensors may be provided.

In order to implement the ESC function, the control unit 400 includes a rotation rate sensor or a yaw rate sensor, a steering angle sensor, (Speed Sensor) may be further provided.

3 is a block diagram schematically illustrating a method of controlling a brake system of a hybrid vehicle according to a second embodiment of the present invention.

4 is a flowchart illustrating a method of controlling a brake system of a hybrid vehicle according to an embodiment of the present invention.

Referring to FIGS. 3 and 4, a method of controlling a brake system of a hybrid vehicle and an electric vehicle according to a second embodiment of the present invention will now be described.

The brake system control method of the hybrid vehicle and the electric vehicle according to the present invention includes a booster 120 and a master cylinder 130 interlocked with the brake pedal 110 and a storage tank 140 filled with the fluid.

First, in step S100 of detecting whether the brake pedal 110 is operated, an operation signal of a brake pedal 110 transmitted from an operation sensor (not shown) is sensed.

Next, the step S200 of supplying the fluid to the wheel cylinder 20 through the in-line valve 220 is performed when the operation signal of the brake pedal 110 is transmitted from the operation sensor to the control unit 400, 210).

At the same time, in step S200, the in-valve 220 and the out-valve 230 are kept open to open the first hydraulic line L1.

At this time, the fluid stored in the storage tank 140 is transferred to the wheel cylinders 20 of the front and rear wheels of the vehicle by the pumping pressure of the hydraulic pump 210.

In step S200, when the operation of the brake pedal 110 is detected (S210), the step of cutting off the connection line between the master cylinder 130 and the wheel cylinder 20 with a cut valve (generating a braking force) .

That is, when the brake pedal 110 is not operated, the fluid in the storage tank 140 is not transmitted to the wheel cylinders 20.

Next, the step S300 of supplying the fluid to the wheel cylinder through the in-line valve 220 is performed by measuring the pressure of the fluid to be delivered to the wheel cylinders 20 through the hydraulic pump 210, using the sensing unit 300 do.

In step S300, the sensing unit 300 may measure the pressure of the fluid flowing along the first hydraulic line L1 (S310).

Finally, the step S400 of measuring the pressure of the fluid using the sensing unit calculates a difference value by comparing the measured pressure delivered from the sensing unit 300 with a predetermined reference pressure.

At this time, when a difference value between the measured pressure and the reference pressure occurs, the control unit 400 may control the operation of the out-valve 230 or the accumulator 240 to compensate the difference value.

For example, when the measured pressure is greater than the reference pressure, the control unit 400 may down-compensate the difference value through the opening of the out-valve 230.

On the contrary, when the measured pressure is smaller than the reference pressure, the control unit 400 can up-compensate the difference value through opening the accumulator 240. [

Alternatively, the out-valve 230 and the accumulator 240 may perform their own opening and closing by the pressure of the fluid without controlling the operation of the control unit 400.

That is, the out-valve 230 may be kept open by the control unit 400 when the brake pedal 110 is actuated, and may have its own fluid discharge function in this state.

If the measured pressure of the sensing unit 300 is higher than the reference pressure preset in the control unit 400 in the step S400, the pressure in the reservoir tank 140 or the master cylinder 130 is controlled via the out- Lt; / RTI >

Conversely, when the measured pressure of the sensing unit 300 is lower than the preset reference pressure in the control unit 400 in the step S400, the fluid stored in the accumulator 240 is supplied to the in-valve 220 and the wheel cylinder 20 To the first hydraulic line L2 between the first hydraulic line L2 and the second hydraulic line L2.

As a result, the present invention can instantaneously compensate for pressure change of the fluid by referring to the valve opening information.

As a result, it is possible to prevent the vibration from being generated due to the momentary drop and overshoot of the boost pressure, and the durability of the valve can be prevented from being lowered by the frequent control operation.

Although the embodiments of the brake system and the control method of the hybrid and electric vehicle of the present invention have been described above, it is apparent that various modifications are possible within the scope of the present invention.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

It is to be understood that the foregoing embodiments are illustrative and not restrictive in all respects and that the scope of the present invention is indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

10: Wheel 20: Wheel cylinder
100: drive unit 110: brake pedal
120: Booster 130: Master cylinder
140: Storage tank 200: Hydraulic supply unit
210: Hydraulic pump 220: In valve
230: out valve 240: accumulator
250: Cut valve 300: Detection unit
310: compensation value detection sensor 400: control unit
L1: first hydraulic line L2: second hydraulic line
L3: Third hydraulic line

Claims (10)

A booster for interlocking with a brake pedal; a drive unit having a master cylinder and a storage tank filled with a fluid;
A hydraulic pressure pump for pumping the fluid of the storage tank; an in-valve / out-valve provided on the hydraulic line between the storage tank and the wheel cylinders; unit;
A sensing unit for measuring a pressure of the fluid flowing along the hydraulic line when the brake pedal is operated; And
And a control unit for compensating the difference value by discharging the fluid of the out-valve or controlling the supply of the fluid of the accumulator when a difference between the measured pressure transmitted from the sensing unit and a predetermined reference pressure is generated Features a hybrid and electric vehicle braking system. The method according to claim 1,
The out-
Wherein the fluid is delivered to the reservoir tank or the master cylinder via a hydraulic line when the fluid is discharged. The method according to claim 1,
The accumulator includes:
Wherein the fluid is filled inside when the hydraulic pump is driven, and the fluid is supplied to the hydraulic line between the in-valve and the wheel cylinder. The method according to claim 1,
In the hydraulic pressure supply portion,
A cut valve is further provided on the hydraulic line between the master cylinder and the wheel cylinder,
The cut-
And the flow of fluid is blocked only at the time of operation of the brake pedal. The method according to claim 1,
Wherein the control unit comprises:
Characterized in that the reference pressure of different levels is preset according to the operating radius of the brake pedal. The method according to claim 1,
In the control unit,
And an operation sensor for detecting the operation of the brake pedal is electrically connected to the brake pedal. 1. A brake system control method for a hybrid and electric vehicle having a booster interlocked with a brake pedal, a master cylinder, and a storage tank filled with a fluid,
Detecting whether the brake pedal is operated when the vehicle is turned on;
Driving the hydraulic pump to supply the fluid of the storage tank to the wheel cylinder through the in-valve when the operation of the brake pedal is sensed;
Measuring a pressure of the fluid transferred to the wheel cylinder through the hydraulic pump using a sensing unit; And
And compensating the difference value by discharging the fluid of the out-valve or controlling the supply of the fluid of the accumulator when a difference between the measured pressure and the preset reference pressure is generated from the sensing unit A method of controlling a brake system of a hybrid and electric vehicle. The method of claim 7,
In supplying oil to the wheel cylinder through the in-line valve,
And disconnecting the connection line between the master cylinder and the wheel cylinder with a cut valve when the operation of the brake pedal is sensed. The method of claim 7,
In compensating the difference value,
And when the measured pressure is higher than a predetermined reference pressure, the control valve transmits the brake fluid to the storage tank or the master cylinder through the out-valve. The method of claim 7,
In compensating the difference value,
Wherein when the measured pressure is lower than a predetermined reference pressure, the fluid stored in the accumulator is supplied onto a connection line between the in-valve and the wheel cylinder.

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