KR20120003291A - Brake control system and the method for electric vehicle and hybrid vehicle - Google Patents

Abstract

PURPOSE: A brake control apparatus of an electric vehicle and hybrid vehicle and a control method thereof are provided to use hydraulic brake force and regenerative brake force according to the pedal effort of a brake pedal, thereby improving braking performance. CONSTITUTION: An electronic control unit(ECU)(100) controls the size of regenerative brake force according to a charging amount of a battery and distance from a preceding vehicle. A hydraulic line switching valve(80) opens or closes a hydraulic line which supplies fluid pressure generated in a master cylinder to a brake cylinder according to a signal applied from the ECU. The ECU receives a signal from one or more devices among a pedal effort sensor(30) measuring the pedal effort of a brake, a distance measuring sensor(40) measuring the distance with the preceding vehicle, a speed measuring device(50) measuring the speed of the preceding vehicle, a vehicle speed sensor(60) detecting car speed of a driving vehicle, and a charged amount measuring sensor(70) measuring a charging amount the battery.

Description

BRAKE CONTROL SYSTEM AND THE METHOD FOR ELECTRIC VEHICLE AND HYBRID VEHICLE}

The present invention relates to a brake control apparatus and method for electric and hybrid vehicles.

In general, a hydraulic brake device of a vehicle includes a brake pedal that the driver presses for braking, a brake cylinder installed on the brake discs of the front left / right wheels and the rear left / right wheels of the vehicle to apply friction braking force to the brake discs, It is connected to the brake cylinder and the hydraulic line and includes a master cylinder for providing hydraulic pressure to the brake disc via the hydraulic line when the brake pedal is pressed.

On the other hand, in recent years, research to commercialize a hybrid car or an electric vehicle is progressing rapidly. Such a hybrid car or an electric vehicle is a motor driven by electricity, and the vehicle is driven by rotating the driving wheels of the vehicle. How much efficient use of the electric energy to drive the?

In order to solve this problem, when the deceleration or braking command is generated from the driver, the wheel drive motor functions as a generator to store the electric energy generated in the capacitor. By the way, while the wheel drive motor functions as a generator, a braking force is generated on the wheels. Such a braking force is called a regenerative braking force.

As a result, the braking force applied to the wheel is the sum of the regenerative braking force by the wheel drive motor and the hydraulic braking force by the hydraulic brake device.

However, the brake device of the conventional electric vehicle or hybrid vehicle as described above is controlled to preferentially use the regenerative braking force so that an energy storage device such as a battery is overcharged by regenerative braking, thereby causing a risk of failure or explosion.

In addition, the regenerative braking force decreases at high speed due to the characteristics of the motor, so it is necessary to calculate the maximum regenerative braking force in consideration of this.

In addition, when the regenerative braking force is used first, there is a problem that if a malfunction occurs in the system, it may lead to a fatal accident.

The present invention is to provide a brake control apparatus and control method of the electric vehicle and hybrid vehicle that can prevent the excessive braking force of the vehicle is generated to extend the life of the brake pad, and to prevent overcharging and explosion of the battery.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

As an example, the brake control apparatus of the electric vehicle and the hybrid vehicle may reduce the magnitude of the regenerative braking force when the distance from the front vehicle is far from the front vehicle or when the battery charge amount is high, and when the distance from the front vehicle is close or the battery charge amount is low, An electronic control unit (ECU) for controlling the regenerative braking force and a hydraulic line on / off valve for opening and closing the hydraulic line for supplying hydraulic pressure generated in the master cylinder to the brake cylinder according to a signal applied from the electronic control unit (ECU). Include.

The electronic control unit (ECU) includes a stepping force sensor for measuring a stepping force of a brake, a distance measuring sensor for measuring a distance between the front car, a speed measuring device for measuring the speed of the front car, and a vehicle speed sensor for detecting a vehicle speed of a running vehicle And, characterized in that for receiving a signal from at least one of the charge amount measuring sensor for measuring the charge amount of the battery.

The brake control method of the electric vehicle and the hybrid vehicle detects the distance to the vehicle ahead and the speed of the vehicle ahead, detects the current charge amount of the battery, detects the speed of the vehicle being driven, and based on the signal detected in the step. Setting the regenerative braking force profile, detecting the pedal pedal effort, and using the regenerative braking force and the hydraulic braking force simultaneously when the pedal pedal effort is greater than or equal to the set value, and in the step, the brake pedal If only the regenerative braking force is less than the set value of the step of using only the regenerative braking force, in the above step, to warn the driver when the regenerative braking force is insufficient, and to use the hydraulic braking force at the same time, in the above step, the distance from the vehicle ahead or the amount of battery charge Regenerative braking to prevent overcharging of the battery when above the set value Of a step of reducing the size.

The brake control apparatus and the control method of the electric vehicle and the hybrid vehicle of the present invention uses the regenerative braking force when the brake pedal effort is less than or equal to the set value, and simultaneously uses the regenerative braking force and the hydraulic braking force when the brake pedal force is greater than or equal to the set value. By braking, the braking performance can be improved, battery overcharge and damage can be prevented, and the life of the brake pedal can be extended.

1 is a block diagram of a brake apparatus of a vehicle according to an embodiment of the present invention.
2 is a block diagram illustrating an apparatus for controlling a brake of a vehicle according to an exemplary embodiment of the present invention.
3 is a flowchart illustrating a brake control method of a vehicle according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms that are specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. Definitions of these terms should be made based on the contents throughout the specification.

1 is a block diagram showing a hydraulic brake of a vehicle according to an embodiment of the present invention, Figure 2 is a block diagram showing a brake control apparatus for a vehicle according to an embodiment of the present invention.

As shown in FIG. 1, a hydraulic brake of a vehicle according to an embodiment is installed in a brake pedal 10 in which a driver presses for braking, a brake disc of a front left / right wheel and a rear left / right wheel of a vehicle, respectively. Brake cylinder (not shown) for applying a friction braking force to the brake disk, and the master cylinder 20 is connected to the brake cylinder and the hydraulic line to press the brake pedal 10 to provide hydraulic pressure to the brake disk through the hydraulic line do.

The brake pedal 10 is connected to the push rod 22 of the master cylinder 20 and is rotatably supported by the hinge shaft 16 on the hinge bracket 14 mounted on the vehicle body side 12. The hinge shaft 16 is provided with a stepping force sensor 30 that measures the stepping force on the brake pedal 10 and transmits it to the electronic control unit (ECU) 100.

Brake control apparatus according to an embodiment is a step sensor 30 for measuring the stepping force of the brake pedal 10, the distance measuring sensor 40 for measuring the distance to the front car, and a speed measuring device for measuring the speed of the front car 50, a vehicle speed sensor 60 for detecting a vehicle speed of a running vehicle, a charge measurement sensor 70 for measuring the amount of charge of a battery, and an electronic control unit (ECU) to which a signal is applied from the sensors and the apparatus described above. 100, the hydraulic line on-off valve 80 for opening and closing the hydraulic line for supplying the hydraulic pressure generated in the master cylinder 20 to the brake cylinder according to the signal applied from the electronic control unit 100, It is installed on the bulletin board includes a display unit 90 to inform the driver of the braking degree using the regenerative braking force and to warn the driver when the braking force is insufficient.

The electronic control unit (ECU) 100 may be a microcontroller, a microprocessor, or a processor having a similar function.

The speed measuring apparatus 50 may be a camera, the distance measuring sensor 40 may be an ultrasonic sensor. The speed measuring device 50 and the distance measuring sensor 40 are installed in front of the vehicle.

In this way, a vehicle brake control method by the display device constituted will be described below.

3 is a flowchart illustrating a brake control method according to an embodiment of the present invention.

First, the electronic control unit (ECU) 100 detects the distance to the vehicle ahead according to the signal applied from the distance measuring sensor 40, and detects the speed of the vehicle ahead according to the signal applied from the speed measuring device 50. . In addition, the electronic control unit (ECU) 100 receives the speed of the vehicle in operation from the vehicle speed sensor 60.

The electronic control unit (ECU) 100 detects a current charge amount of the battery according to a signal applied from the charge amount sensor 70. (S20).

In this way, the electronic control unit (ECU) 100 sets the regenerative braking force profile based on signals applied from various sensors and devices (S30).

In this case, the regenerative braking force profile has a small distance from the vehicle in front of the vehicle, or a large amount of the regenerative braking force when the amount of charge of the battery is high.

In order to prevent excessive braking force from being generated during high-speed driving, the vehicle is set to decelerate only to the same speed as the front vehicle during high-speed driving.

In addition, the electronic control unit (ECU) 100 displays on the display panel 90 whether the braking is possible using only the regenerative braking force according to the regenerative braking force profile and informs the driver.

In this state, when the driver presses the brake pedal 10, the pedal force of the brake pedal 10 is applied to the electronic control unit (ECU) 100 from the step force sensor 30, and the electronic control unit (ECU) 100 is applied. In response to the signal applied from the step force sensor 30, it is determined whether the step force of the brake pedal 10 is greater than or equal to the set value.

The electronic control unit (ECU) 100 uses the regenerative braking force and the hydraulic braking force at the same time when the pedal force of the brake pedal 10 is greater than or equal to the set value. (S60) That is, by operating the hydraulic line on / off valve 80 in the opening direction, the master The hydraulic pressure generated in the cylinder 20 is provided to the brake cylinder. Then, the hydraulic braking force and the regenerative braking force work simultaneously to improve the braking performance and achieve a stable braking. Here, the power setting value is set to about 30%.

On the contrary, when the pedal force of the brake pedal 10 is less than or equal to the set value, only the regenerative braking force is used (S80). That is, the hydraulic pressure generated in the master cylinder 20 is operated by closing the hydraulic line opening / closing valve 80. Do not serve as a brake cylinder. The brake is then provided with a suitable braking force to prevent the brake pads from being damaged.

In addition, the electronic control unit (ECU) 100 may reduce the size of the regenerative braking force to prevent overcharging of the battery when the distance from the front vehicle is far from the front vehicle or the charge amount of the battery is high, and the distance from the front vehicle is far from the front vehicle. If it is below the set value, use a large regenerative braking force.

And, when the electronic control unit (ECU) 100 performs the braking with only the regenerative braking force, the electronic control unit (ECU) 100 determines whether sufficient braking is possible by the regenerative braking force alone, and warns the display unit 90 that the braking force is insufficient if it is determined that the braking force is not sufficient. In addition, by operating the hydraulic line on-off valve 80 provides hydraulic braking force. (S70, S90)

Although embodiments according to the present invention have been described above, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments of the present invention are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the following claims.

10: brake pedal 20: master cylinder
30: step sensor 40: distance measuring sensor
50: speed measuring sensor 60: vehicle speed sensor
70: filling amount measuring sensor 80: hydraulic line closing valve
90: display unit 100: electronic control unit (ECU)

Claims (9)

An electronic control unit (ECU) for reducing the size of the regenerative braking force when the distance to the front car is far or the battery is high, and using the large regenerative braking force when the distance to the front car is short or the battery charge is low; And
And a hydraulic line on / off valve for opening and closing a hydraulic line for supplying hydraulic pressure generated in the master cylinder to the brake cylinder according to a signal applied from the electronic control unit (ECU). The method of claim 1,
The electronic control unit (ECU) includes a stepping force sensor for measuring a stepping force of a brake, a distance measuring sensor for measuring a distance between the front car, a speed measuring device for measuring the speed of the front car, and a vehicle speed sensor for detecting a vehicle speed of a running vehicle And a brake control apparatus for an electric vehicle and a hybrid vehicle receiving a signal from at least one of a charge level sensor for measuring a charge amount of a battery. The method of claim 1,
Receiving a signal applied from the electronic control unit (ECU), the electric vehicle is installed on the instrument panel of the vehicle further includes a display unit for notifying the driver of the braking possible by using the regenerative braking force and warning the driver when the braking force is insufficient; Braking controls in hybrid cars. The method of claim 1,
The step sensor is installed on the hinge shaft of the brake pedal brake control device for an electric vehicle and a hybrid vehicle, characterized in that for measuring the degree of rotation of the brake pedal. The method of claim 1,
The distance measuring sensor is composed of an ultrasonic sensor, the speed measuring device is a brake control device of an electric vehicle and a hybrid vehicle, characterized in that the camera. Detecting a distance to the vehicle in front of the vehicle and a speed of the vehicle in front of the vehicle, detecting a current charge amount of the battery, and detecting a speed of the driving vehicle;
Setting a regenerative braking force profile based on the signal detected in the step;
Detecting the foot force of the brake pedal;
In the step, using the regenerative braking force and the hydraulic braking force at the same time when the pedal force of the brake pedal is equal to or larger than the set value;
In the step, using only the regenerative braking force when the pedal pedal effort is less than or equal to the set value;
In the step, warning the driver when the regenerative braking force is insufficient and simultaneously using the hydraulic braking force; And
In the step, the brake control method of the electric vehicle and hybrid vehicle comprising the step of reducing the size of the regenerative braking force to prevent overcharging of the battery when the distance to the front vehicle is far or the battery charge is more than the set value. The method of claim 6,
The control method may include displaying on the instrument panel whether or not the regenerative braking force may be provided on the display panel according to the regenerative braking force profile.
In the above step, if the regenerative braking force alone is not sufficient, the display panel warns of the lack of braking force, and using the hydraulic braking force at the same time, the control method of the electric vehicle and hybrid vehicle further comprising the step of using. The method of claim 6,
A brake pedal control method of the electric pedal and the hybrid vehicle, characterized in that 30% set value. The method of claim 8,
The step of setting the regenerative braking force profile is a brake control method of an electric vehicle and a hybrid vehicle, characterized in that it is set to decelerate only to the same speed as the front vehicle when driving at high speed to prevent excessive braking force generated during high-speed driving.

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