阅读说明：本技术 车辆制动控制方法、制动系统和车辆 (Vehicle brake control method, brake system and vehicle ) 是由 杨慧敏 毛辉 延磊 于 2021-10-28 设计创作，主要内容包括：本发明公开了一种车辆制动控制方法、制动系统和车辆,其中,车辆包括机械制动子系统、电制动子系统和防抱死制动子系统,车辆制动控制方法用于整车控制器,车辆制动控制方法包括：获取车辆制动踏板的开度信号；根据车辆制动踏板的开度信号确定车辆进入紧急制动模式；控制车辆的机械制动子系统和电制动子系统同时作用,其中,控制电制动子系统进行反拖运行,并在检测到防抱死制动子系统的启动信号时控制电制动子系统退出反拖运行。本发明实施例提出的车辆制动控制方法,能有效协调控制机械制动力与电制动力,既保证车辆有足够的制动能力,又保证车辆在制动过程中的制动能量回收最大化。(The invention discloses a vehicle brake control method, a brake system and a vehicle, wherein the vehicle comprises a mechanical brake subsystem, an electric brake subsystem and an anti-lock brake subsystem, the vehicle brake control method is used for a whole vehicle controller, and the vehicle brake control method comprises the following steps: acquiring an opening signal of a brake pedal of a vehicle; determining that the vehicle enters an emergency braking mode according to the opening signal of the vehicle brake pedal; and controlling a mechanical brake subsystem and an electric brake subsystem of the vehicle to act simultaneously, wherein the electric brake subsystem is controlled to perform anti-drag operation, and the electric brake subsystem is controlled to quit the anti-drag operation when a starting signal of the anti-lock brake subsystem is detected. The vehicle braking control method provided by the embodiment of the invention can effectively coordinate and control the mechanical braking force and the electric braking force, thereby ensuring that the vehicle has enough braking capacity and the braking energy recovery maximization of the vehicle in the braking process.)

1. A vehicle brake control method is characterized in that a vehicle comprises a mechanical brake subsystem, an electric brake subsystem and an anti-lock brake subsystem, and the vehicle brake control method is used for a vehicle control unit, and the method comprises the following steps:

acquiring an opening signal of the vehicle brake pedal;

determining that the vehicle enters an emergency braking mode according to the opening signal of the vehicle brake pedal;

and controlling a mechanical brake subsystem and an electric brake subsystem of the vehicle to act simultaneously, wherein the electric brake subsystem is controlled to perform anti-drag operation, and the electric brake subsystem is controlled to exit the anti-drag operation when a starting signal of the anti-lock brake subsystem is detected.

2. The vehicle brake control method according to claim 1, characterized by further comprising:

acquiring a vehicle speed signal and the charge state information of a vehicle storage battery;

determining that the vehicle enters a deceleration braking mode according to the vehicle speed and the opening degree signal;

and controlling the electric braking subsystem and the mechanical braking subsystem according to the opening degree signal and the state of charge information.

3. The vehicle braking control method of claim 2, wherein controlling the electric braking subsystem and the mechanical braking subsystem based on the opening degree signal and the state of charge information comprises:

when the opening signal is smaller than or equal to the idle opening threshold value, controlling the electric brake subsystem to brake by a first electric brake torque, wherein the first electric brake torque is the anti-drag torque of the engine when the driver releases the accelerator pedal and the vehicle brake pedal simultaneously;

and when the opening signal is larger than a non-idle opening threshold value, controlling the electric braking subsystem and the mechanical braking subsystem to perform superposition braking according to the charge state information and the opening signal.

4. The vehicle braking control method of claim 3, wherein controlling the electric braking subsystem and the mechanical braking subsystem for superimposed braking based on the state of charge information and the opening signal comprises:

controlling the electric braking subsystem and the mechanical braking subsystem to act simultaneously;

and controlling the mechanical braking torque of the mechanical braking subsystem to increase in an accelerated manner according to the opening degree signal, outputting motor power and in-cylinder braking power to control the electric braking subsystem to brake when the state of charge of the storage battery is determined to be in a charging state according to the state of charge information, or outputting in-cylinder braking power to control the electric braking subsystem to brake when the state of charge of the storage battery is determined to be greater than a preset charge threshold value according to the state of charge information, and controlling the braking force of the electric braking subsystem to gradually decrease until the braking force is zero along with the gradual decrease of the vehicle speed.

5. The vehicle brake control method according to claim 2, characterized by further comprising:

receiving a starting instruction of a down long slope mode;

acquiring gradient information;

and controlling the electric braking subsystem and the mechanical braking subsystem according to the vehicle speed, the gradient information and the state of charge information.

6. The vehicle braking control method of claim 5, wherein controlling the electric braking subsystem and the mechanical braking subsystem based on the vehicle speed, the grade information, and the state of charge information comprises:

obtaining required braking power according to the vehicle speed and the gradient information;

determining that the storage battery is in a charging state according to the charge state information, and outputting electric braking power, wherein the electric braking power comprises motor power and in-cylinder braking power to control the electric braking subsystem, and outputting in-cylinder braking power to control the electric braking subsystem until the charge state reaches a preset charge threshold, or determining that the charge state of the storage battery is greater than the preset charge threshold according to the charge state information, and outputting electric braking power, wherein the electric braking power comprises in-cylinder braking power to control the electric braking subsystem;

and when the electric braking power is greater than or equal to the required braking power, controlling the vehicle to descend at a first vehicle speed and a constant speed.

7. The vehicle brake control method according to claim 6, characterized by further comprising:

when the electric braking power is smaller than the required braking power, controlling the mechanical braking subsystem to act according to the opening degree signal of the brake pedal;

and determining that the vehicle speed is less than a preset vehicle speed, obtaining new required braking power according to the vehicle speed and the gradient information until the electric braking power and the mechanical braking power meet the new required braking power, and controlling the vehicle to descend at a second vehicle speed at a constant speed.

8. A braking system, comprising:

a mechanical braking subsystem, an electric braking subsystem and an anti-lock braking subsystem;

the brake pedal opening degree detection unit is used for detecting an opening degree signal of a brake pedal of the vehicle;

a vehicle speed sensor for detecting a vehicle speed;

the battery manager is used for acquiring the charge state information of the vehicle storage battery;

a gradient sensor for detecting gradient information of a road on which the vehicle is traveling;

a vehicle control unit connected to the mechanical braking subsystem, the anti-lock braking subsystem, the electric braking subsystem, the brake pedal opening degree detection unit, the vehicle speed sensor, the battery manager, and the gradient sensor, for controlling the mechanical braking subsystem, the anti-lock braking subsystem, and the electric braking subsystem according to the vehicle braking control method of any one of claims 1 to 7.

9. The braking system of claim 8, further comprising:

and the long downhill slope mode starting unit is connected with the vehicle control unit and is used for receiving an operation instruction for starting the long downhill slope mode.

10. A vehicle comprising a battery and a braking system according to claim 8 or 9, wherein the battery is connected to an electric braking subsystem of the braking system.

Technical Field

The invention relates to the technical field of vehicles, in particular to a vehicle brake control method, a brake system and a vehicle.

Background

The brake system is an important component for ensuring the safety of the vehicle, and directly influences the driving safety of the vehicle. The conventional commercial vehicle braking system is usually designed as a mechanical braking system, and the mechanical braking system adopts the conventional braking system principle, when a driver touches a brake pedal, a brake acts on the wheel edge to brake, so that the vehicle is controlled to decelerate or stop. However, since the inertia of the vehicle is large, when the vehicle needs to be braked at a high speed for a long time with a large braking force, the brake is prone to high temperature and heat fading, so that the service life is affected, and the kinetic energy of the vehicle is converted into heat energy through the brake and lost in the braking process. For a new energy vehicle comprising a motor and a battery, when the vehicle needs braking, the motor can utilize counter electromotive force to brake, and the energy during braking can be converted into electric energy to be stored in the battery, so that the braking energy recovery is realized.

However, for the electromechanical hybrid braking system, how to maximize the braking energy recovery on the basis of ensuring the braking efficiency needs to provide an optimization strategy.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, one of the objectives of the present invention is to provide a vehicle braking control method, which can effectively coordinate and control mechanical braking force and electrical braking force, and ensure that the vehicle has sufficient braking capability and the braking energy recovery of the vehicle in the braking process is maximized.

The second objective of the present invention is to provide a braking system.

The invention also aims to provide a vehicle.

In order to achieve the above object, a vehicle braking control method according to an embodiment of a first aspect of the present invention is a vehicle braking control method for a vehicle control unit, the vehicle including a mechanical braking subsystem, an electric braking subsystem, and an antilock braking subsystem, the method including: acquiring an opening signal of the vehicle brake pedal; determining that the vehicle enters an emergency braking mode according to the opening signal of the vehicle brake pedal; and controlling a mechanical brake subsystem and an electric brake subsystem of the vehicle to act simultaneously, wherein the electric brake subsystem is controlled to perform anti-drag operation, and the electric brake subsystem is controlled to exit the anti-drag operation when a starting signal of the anti-lock brake subsystem is detected.

According to the vehicle braking control method provided by the embodiment of the invention, mechanical braking and electric braking are integrated, and in an emergency braking mode, the vehicle controller controls the mechanical braking subsystem and the electric braking subsystem to act simultaneously so as to realize electromechanical composite braking, so that the braking energy efficiency can be ensured, and the maximization of braking energy recovery can be realized. And when a starting signal of the anti-lock braking subsystem is detected, the vehicle controller controls the electric braking subsystem to quit the anti-drag operation, and brakes the vehicle in a pure mechanical braking mode so as to meet the safety requirement on the vehicle in an emergency braking mode and ensure the stability of the vehicle and the safety of a driver.

In some embodiments of the invention, the vehicle braking control method further comprises: acquiring a vehicle speed signal and the charge state information of a vehicle storage battery; determining that the vehicle enters a deceleration braking mode according to the vehicle speed and the opening degree signal; and controlling the electric braking subsystem and the mechanical braking subsystem according to the opening degree signal and the state of charge information.

In some embodiments of the present invention, controlling the electric brake subsystem and the mechanical brake subsystem according to the opening degree signal and the state of charge information comprises: when the opening signal is smaller than or equal to the idle opening threshold value, controlling the electric brake subsystem to brake by a first electric brake torque, wherein the first electric brake torque is the anti-drag torque of the engine when the driver releases the accelerator pedal and the vehicle brake pedal simultaneously; and when the opening signal is larger than a non-idle opening threshold value, controlling the electric braking subsystem and the mechanical braking subsystem to perform superposition braking according to the charge state information and the opening signal.

In some embodiments of the present invention, controlling the electric braking subsystem and the mechanical braking subsystem to perform superimposed braking according to the state of charge information and the opening degree signal includes: controlling the electric braking subsystem and the mechanical braking subsystem to act simultaneously; and controlling the mechanical braking torque of the mechanical braking subsystem to increase in an accelerated manner according to the opening degree signal, outputting motor power and in-cylinder braking power to control the electric braking subsystem to brake when the state of charge of the storage battery is determined to be in a charging state according to the state of charge information, or outputting in-cylinder braking power to control the electric braking subsystem to brake when the state of charge of the storage battery is determined to be greater than a preset charge threshold value according to the state of charge information, and controlling the braking force of the electric braking subsystem to gradually decrease until the braking force is zero along with the gradual decrease of the vehicle speed.

In some embodiments of the invention, the vehicle braking control method further comprises: receiving a starting instruction of a down long slope mode; acquiring gradient information; and controlling the electric braking subsystem and the mechanical braking subsystem according to the vehicle speed, the gradient information and the state of charge information.

In some embodiments of the invention, controlling the electric brake subsystem and the mechanical brake subsystem based on the vehicle speed, the grade information, and the state of charge information comprises: obtaining required braking power according to the vehicle speed and the gradient information; determining that the storage battery is in a charging state according to the charge state information, and outputting electric braking power, wherein the electric braking power comprises motor power and in-cylinder braking power to control the electric braking subsystem, and outputting in-cylinder braking power to control the electric braking subsystem until the charge state reaches a preset charge threshold, or determining that the charge state of the storage battery is greater than the preset charge threshold according to the charge state information, and outputting electric braking power, wherein the electric braking power comprises in-cylinder braking power to control the electric braking subsystem; and when the electric braking power is greater than or equal to the required braking power, controlling the vehicle to descend at a first vehicle speed and a constant speed.

In some embodiments of the invention, the vehicle braking control method further comprises: when the electric braking power is smaller than the required braking power, controlling the mechanical braking subsystem to act according to the opening degree signal of the brake pedal; and determining that the vehicle speed is less than a preset vehicle speed, obtaining new required braking power according to the vehicle speed and the gradient information until the electric braking power and the mechanical braking power meet the new required braking power, and controlling the vehicle to descend at a second vehicle speed at a constant speed.

In order to achieve the above object, an embodiment of the second aspect of the present invention provides a brake system, including: a mechanical braking subsystem, an electric braking subsystem and an anti-lock braking subsystem; the brake pedal opening degree detection unit is used for detecting an opening degree signal of a brake pedal of the vehicle; a vehicle speed sensor for detecting a vehicle speed; the battery manager is used for acquiring the charge state information of the vehicle storage battery; a gradient sensor for detecting gradient information of a road on which the vehicle is traveling; the vehicle control unit is connected with the mechanical braking subsystem, the anti-lock braking subsystem, the electric braking subsystem, the brake pedal opening degree detection unit, the vehicle speed sensor, the battery manager and the gradient sensor and is used for controlling the mechanical braking subsystem, the anti-lock braking subsystem and the electric braking subsystem according to the vehicle braking control method.

According to the braking system provided by the embodiment of the invention, the vehicle control unit 8 controls the operation state of the mechanical braking subsystem and/or the electric braking subsystem according to the opening degree signal of the vehicle braking pedal, the vehicle speed, the charge state information of the vehicle storage battery and the gradient information of the vehicle running road, and coordinates and controls the electric braking and the mechanical braking in an emergency braking mode, a deceleration braking mode or a long-slope descending mode, so that the vehicle braking control method provided by any one of the above embodiments is realized, the braking energy efficiency of the braking system can be ensured, and the maximization of the braking energy recovery can be realized.

In some embodiments of the invention, the braking system further comprises: and the long downhill slope mode starting unit is connected with the vehicle control unit and is used for receiving an operation instruction for starting the long downhill slope mode.

In order to achieve the above object, a third aspect of the present invention provides a vehicle including a battery and the brake system of the above embodiment, wherein the battery is connected with an electric brake subsystem of the brake system.

According to the vehicle provided by the embodiment of the invention, the braking system comprising the mechanical braking subsystem and the electric braking subsystem is arranged in the vehicle, electromechanical composite braking can be realized, the vehicle braking control method provided by any embodiment is adopted for control, an optimization method is adopted during vehicle braking, the optimal electric braking force is calculated in each braking mode with the aim of maximizing the braking energy feedback efficiency, and the distributed electric braking force is sent to the electric braking subsystem, so that the coordinated control of the electric braking and the mechanical braking is realized, the braking energy efficiency is ensured, and the maximization of the braking energy recovery is realized.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of a vehicle braking control method according to one embodiment of the present invention;

FIG. 2 is a schematic illustration of the distribution of braking torque with vehicle brake pedal depth according to one embodiment of the present invention;

FIG. 3 is a flow chart of a vehicle braking control method according to another embodiment of the present invention;

FIG. 4 is a flow chart of a vehicle braking control method according to yet another embodiment of the present invention;

FIG. 5 is a flow chart of a vehicle braking control method according to yet another embodiment of the present invention;

FIG. 6 is a graphical illustration of brake torque versus time for a vehicle in a downhill mode in accordance with an embodiment of the present invention;

FIG. 7 is a schematic representation of vehicle speed versus time for a vehicle in a downhill mode in accordance with one embodiment of the present invention;

FIG. 8 is a flowchart of a vehicle braking control method according to yet another embodiment of the invention;

FIG. 9 is a block diagram of a braking system according to one embodiment of the present invention;

FIG. 10 is a block diagram of a braking system according to one embodiment of the present invention;

FIG. 11 is a block diagram of a vehicle according to one embodiment of the present invention.

Reference numerals:

a vehicle 1000;

a brake system 10, a battery 20;

the system comprises a mechanical brake subsystem 1, an electric brake subsystem 2, an anti-lock brake subsystem 3, a brake pedal opening degree detection unit 4, a vehicle speed sensor 5, a battery manager 6, a gradient sensor 7, a vehicle control unit 8 and a long-slope descending mode starting unit 9.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

A vehicle brake control method according to an embodiment of the invention is described below with reference to fig. 1 to 6.

In some embodiments of the invention, the vehicle includes a mechanical braking subsystem, an electric braking subsystem, and an anti-lock braking subsystem, and the vehicle braking control method is for a vehicle control unit.

In an embodiment, the mechanical braking subsystem comprises a power driving assembly and a braking executing member, the power driving assembly is electrically connected with the vehicle control unit, and the power driving assembly is mechanically connected with the braking executing member, so that the mechanical braking of the vehicle can be realized. The power drive assembly may be driven by gas or liquid, and may include, for example, various components and conduits for transmitting energy to brake actuators, such as brake pedals, master cylinders, wheel cylinders, and connecting conduits, which generate forces that oppose movement or tendencies of movement of the vehicle, such as brakes, etc. When the vehicle is mechanically braked, the power driving assembly transmits energy to the brake through gas or liquid, the brake and the wheel rub against each other to prevent the rotation or the rotation trend of the wheel, the kinetic energy of the vehicle motion is converted into frictional heat energy and is released into the atmosphere, and therefore mechanical braking is achieved.

The electric braking subsystem comprises a motor and a motor controller, the motor controller is connected with the motor, the motor controller is connected with the vehicle control unit, and the electric braking principle is that the motor is used for outputting reverse dragging torque to brake the vehicle. Specifically, when the vehicle is electrically braked, the motor controller controls the motor to reversely drag, so that the motor serves as a generator, namely the motor brakes the vehicle by using the back electromotive force, and energy generated during braking is converted into electric energy to be stored in the storage battery, so that braking energy recovery is realized.

An anti-lock braking subsystem is an active safety system in a vehicle that prevents wheels from locking when the vehicle is being braked urgently.

As shown in fig. 1, a flowchart of a vehicle brake control method according to an embodiment of the invention is shown, wherein the vehicle brake control method at least includes steps S1-S3, which is described as follows.

And S1, acquiring an opening signal of a brake pedal of the vehicle.

The device comprises a vehicle brake pedal, a vehicle controller, a sensor, a vehicle speed sensor and the like, wherein the sensor and other detection devices can be installed at the brake pedal and used for acquiring the opening degree signal of the vehicle brake pedal in real time and uploading the opening degree signal to the vehicle controller.

And S2, determining that the vehicle enters an emergency braking mode according to the opening degree signal of the vehicle brake pedal.

The vehicle control unit determines the depth of the vehicle brake pedal according to the acquired opening degree signal of the vehicle brake pedal, and can further recognize the intention of the driver and the expected braking strength according to the depth of the vehicle brake pedal, for example, when the driver steps on the brake pedal suddenly, the vehicle control unit determines that the brake pedal reaches a great depth in a short time according to the opening degree signal of the vehicle brake pedal, determines that the driver has an emergency braking intention, and the vehicle enters an emergency braking mode.

And S3, controlling the mechanical brake subsystem and the electric brake subsystem of the vehicle to act simultaneously, wherein the electric brake subsystem is controlled to perform anti-drag operation, and the electric brake subsystem is controlled to exit the anti-drag operation when the starting signal of the anti-lock brake subsystem is detected.

Distribution conditions of electric braking and mechanical braking in an emergency braking mode according to an embodiment of the invention can be described by combining fig. 2, fig. 2 is a schematic diagram of braking torque distribution along with vehicle brake pedal depth according to an embodiment of the invention, wherein a curve (i) represents a rule that electric braking torque changes along with vehicle brake pedal depth, a curve (ii) represents a rule that mechanical braking torque changes along with vehicle brake pedal depth, a curve (iii) represents a rule that electromechanical composite braking torque changes along with vehicle brake pedal depth under an actual working condition, and a dotted line in fig. 2 represents a rule that electromechanical composite braking torque changes along with vehicle brake pedal depth under an ideal state.

Specifically, in the emergency braking mode, the safety of the driver and the entire vehicle is very critical, as can be seen from fig. 2, when the driver steps on the vehicle brake pedal hard, the depth of the vehicle brake pedal is large, for example, when the depth of the brake pedal is N3, the mechanical braking is mainly performed, wherein the mechanical braking strength can be determined according to the magnitude of the output air pressure, and at this time, the brake air pressure is large, and the entire vehicle controller controls the mechanical braking subsystem of the vehicle to act so as to output a large mechanical braking torque, thereby ensuring that a sufficient braking force can be provided.

As can be seen from fig. 2, in the emergency braking mode, the electric braking subsystem outputs the maximum electric braking torque T0 when operating, and the electric braking torque is smaller than the mechanical braking torque, and the electric braking is adopted on the basis of the mechanical braking to achieve braking energy recovery. When the electric braking subsystem acts, the motor controller controls the motor to reversely drag, so that the motor is converted into a generator to generate a counter electromotive force to brake the vehicle, energy generated during braking is converted into electric energy to be stored in the storage battery, and braking energy recovery is further realized.

In other embodiments, when the depth of a brake pedal of a vehicle is continuously increased, an Anti-locked Braking System (ABS) in the vehicle is activated, and when the vehicle controller detects an activation signal of the Anti-lock Braking subsystem, the electric Braking subsystem is controlled to exit the Anti-drag operation, and at this time, the Braking air pressure reaches 10bar, and the mechanical Braking torque output by the mechanical Braking subsystem brakes the vehicle, thereby ensuring the stability and Braking efficiency of the vehicle.

In some embodiments of the present invention, as shown in fig. 3, which is a flowchart of a vehicle braking control method according to another embodiment of the present invention, the vehicle braking control method includes steps S101-S106 in the emergency braking mode, as follows.

S101, a vehicle brake pedal is actuated.

And S102, starting the electric brake.

And S103, opening the mechanical brake.

S104, judging whether the ABS is started or not, and if the judgment result is 'yes', executing the step S105.

And S105, exiting the electric brake.

And S106, emergency braking is carried out on the vehicle, and the vehicle is braked in a pure mechanical braking mode.

According to the vehicle braking control method provided by the embodiment of the invention, mechanical braking and electric braking are integrated, and in an emergency braking mode, the vehicle controller controls the mechanical braking subsystem and the electric braking subsystem to act simultaneously so as to realize electromechanical composite braking, so that the braking energy efficiency can be ensured, and the maximization of braking energy recovery can be realized. And when a starting signal of the anti-lock braking subsystem is detected, the vehicle controller controls the electric braking subsystem to quit the anti-drag operation, and brakes the vehicle in a pure mechanical braking mode so as to meet the requirement on the safety of the vehicle in an emergency braking mode and ensure the stability of the vehicle and the safety of a driver.

In some embodiments of the present invention, as shown in fig. 4, a flowchart of a vehicle braking control method according to another embodiment of the present invention is provided, wherein the vehicle braking control method further includes at least steps S4-S6, as follows.

And S4, acquiring the vehicle speed signal and the charge state information of the vehicle storage battery.

The vehicle management system comprises a vehicle storage battery, a vehicle speed sensor, a battery manager and a vehicle control unit, wherein the vehicle speed sensor can be arranged to acquire a vehicle speed signal and upload the vehicle speed signal to the vehicle control unit, the battery manager is arranged in the vehicle storage battery and used for acquiring the State of charge information of the vehicle storage battery, such as the State of charge (SOC), so as to reflect the residual capacity of the vehicle storage battery, and the battery manager is also used for uploading the State of charge information of the vehicle storage battery to the vehicle control unit.

And S5, determining that the vehicle enters a deceleration braking mode according to the vehicle speed and the opening degree signal.

In an embodiment, the vehicle controller determines that the vehicle is in a running state according to the acquired vehicle speed signal, determines that the depth of a brake pedal of the vehicle is small according to an opening degree signal of the brake pedal of the vehicle, and determines that the vehicle enters a deceleration braking mode if the electric brake is started and the driver has a braking intention.

Specifically, the distribution of the electric braking and the mechanical braking in the deceleration braking mode of the embodiment of the present invention can be described with reference to fig. 2. As shown in fig. 2, when the vehicle is subjected to the deceleration braking, the vehicle brake pedal is actuated, for example, when the vehicle brake pedal depth reaches N1, it is determined that the driver expresses the braking intention, and it is determined that the vehicle enters the deceleration braking mode. The deceleration braking is mainly medium-light braking, and the braking energy recovery is taken as a main target.

And S6, controlling the electric braking subsystem and the mechanical braking subsystem according to the opening degree signal and the state of charge information.

Specifically, in the deceleration braking master mode, the depth of the vehicle brake pedal can be determined according to the opening degree signal of the vehicle brake pedal, and the segmented coordination type control strategy can be set according to the depth of the vehicle brake pedal. For example, the idle stroke section and the non-idle stroke section are set according to the depth of the vehicle brake pedal, and the idle opening degree threshold and the non-idle opening degree threshold can be preset and stored in the vehicle controller. For example, as shown in FIG. 2, a vehicle brake pedal depth equal to N1 may be used as the idle opening threshold and a vehicle brake pedal depth equal to N2 may be used as the non-idle opening threshold, where N1 may be set equal to 4 degrees and N2 may be set equal to 8 degrees. The vehicle control unit obtains the depth of a vehicle brake pedal according to the opening degree signal, and compares the depth with the idle opening degree threshold value and the non-idle opening degree threshold value respectively to determine the braking mode, such as mechanical braking, electric braking or electromechanical combined braking, required by the vehicle.

Specifically, when the opening signal is greater than or equal to the idling opening threshold and less than or equal to the non-idling opening threshold, the electric brake subsystem is controlled to brake by a first electric brake torque, wherein the first electric brake torque is the anti-drag torque of the engine when the driver releases the accelerator pedal and the vehicle brake pedal simultaneously. For example, as shown in fig. 2, when it is determined that the vehicle brake pedal depth is greater than or equal to N1 and less than N2 according to the opening degree signal of the vehicle brake pedal, it is determined that the driver expresses the intention to brake, and when the brake pedal has an idle stroke, the mechanical brake subsystem does not output the mechanical brake torque, and only the electric brake subsystem provides the electric brake torque, that is, when it is determined that the vehicle brake pedal depth is in the idle stroke section, only the electric brake subsystem is controlled to be applied, that is, the electric brake is adopted. At the moment, a driver has good driving feeling, so that the braking torque distribution at the stage not only meets the braking requirement of the driver, but also can fully recover the braking energy, and further improves the economy of the whole vehicle.

Further, when the opening degree signal is larger than the non-idle running opening degree threshold value, the depth of the vehicle brake pedal is determined to be larger than N2, at the moment, the non-idle running section is entered, and the electric brake subsystem and the mechanical brake subsystem are controlled to carry out superposition braking according to the charge state information and the opening degree signal. And controlling the electric braking subsystem and the mechanical braking subsystem to act simultaneously, namely braking the vehicle by adopting a braking mode of superposing the electric braking and the mechanical braking.

Specifically, the mechanical braking torque of the mechanical braking subsystem is controlled to increase in an accelerated manner according to the opening degree signal, that is, the vehicle controller performs electromechanical braking coordination control along with the increase of the depth of a brake pedal of the vehicle, and at the moment, in order to ensure the braking efficiency and safety of the vehicle, the mechanical braking torque is accelerated and increased in a manner consistent with the mechanical braking torque increase manner in the conventional braking manner. The electric braking strength can be determined according to the state of charge information, and when the storage battery is determined to be in a charging state according to the state of charge information, the motor power and the in-cylinder braking power are output to control the electric braking subsystem to brake until the storage battery is fully charged.

Or when the state of charge of the storage battery is determined to be greater than the preset state of charge threshold according to the state of charge information, for example, the preset state of charge threshold may be set to be 100%, that is, the storage battery is fully charged, the in-cylinder braking power is output to control the electric brake subsystem to brake, and as the vehicle speed gradually decreases, the braking force of the electric brake subsystem is controlled to gradually decrease until the braking force is zero. As shown in fig. 2, when the depth of the brake pedal of the vehicle is continuously increased to be larger than N3, the vehicle speed is reduced because the output mechanical brake torque and the output electric brake torque are both kept at a larger degree, so that the motor speed is reduced and the output electric brake torque of the electric brake subsystem is reduced to zero.

In some embodiments of the present invention, as shown in fig. 3, in the deceleration braking mode, the vehicle braking control method includes steps S101, S107-S113, as follows.

S101, a vehicle brake pedal is actuated.

And S102, starting the electric brake.

And S107, judging the SOC state of the vehicle storage battery, namely determining the SOC state of the storage battery according to the SOC information.

And S108, determining that the storage battery is in a charging state.

And S109, outputting the motor power and the in-cylinder brake power to control the electric brake subsystem to brake until the step S110 is reached and the storage battery is fully charged.

And S111, the SOC of the storage battery is 100 percent, namely the storage battery is fully charged.

And S112, outputting in-cylinder brake power to control the electric brake subsystem to brake.

S113, the electric braking force is reduced to 0 as the motor rotation speed is reduced.

According to the vehicle braking control method provided by the embodiment of the invention, in a deceleration braking mode, the vehicle controller controls the electric braking subsystem to operate independently according to the opening degree signal and the charge state information, or controls the mechanical braking subsystem and the electric braking subsystem to act simultaneously to realize electromechanical combined braking, and an optimal electric braking force is calculated by adopting an optimization method aiming at the maximization of the braking energy feedback efficiency, so that the braking energy efficiency can be ensured, the maximization of the braking energy recovery can be realized, and the coordination control of the electric braking and the mechanical braking can be realized.

In other embodiments of the present invention, as shown in fig. 5, a flowchart of a vehicle brake control method according to still another embodiment of the present invention is provided, wherein the vehicle brake control method further includes steps S7-S9, as follows.

And S7, receiving a starting command of the long downhill mode.

Specifically, the driver can press the downhill starting button to send a starting instruction of the long downhill mode, and the vehicle controller can recognize the long downhill intention of the driver according to the starting instruction of the long downhill mode and control the vehicle to enter the long downhill mode.

And S8, acquiring gradient information.

In an embodiment, a gradient sensor may be provided for detecting gradient information of a vehicle traveling road, and the detected gradient information of the vehicle traveling road may be transmitted to the vehicle controller.

And S9, controlling the electric braking subsystem and the mechanical braking subsystem according to the vehicle speed, the gradient information and the state of charge information.

In the embodiment, the law of change of the braking torque in the downhill mode according to the embodiment of the present invention may be described with reference to fig. 6 and 7, and fig. 6 is a schematic diagram of a relationship between the braking torque and time in the downhill mode of a vehicle according to an embodiment of the present invention, in which a curve (a) represents the law of change of the electric braking torque with time, a curve (a) represents the law of change of the mechanical braking torque with time, and a curve (b) represents the law of change of the electric hybrid braking torque with time. FIG. 7 is a schematic representation of vehicle speed versus time for a vehicle in downhill mode in accordance with one embodiment of the present invention.

For example, the time when the driver presses the downhill start button is recorded as 0 time, the vehicle controller determines that the storage battery is in the charging state according to the charge state information, and a time period of 0-t1 shown in fig. 6 is a charging process of the storage battery. When the storage battery is in a charging state, the output in-cylinder braking torque is T2, and the output maximum electric braking torque is T3, including the motor braking torque and the in-cylinder braking torque.

Or determining that the charge state of the storage battery is larger than a preset charge threshold value according to the charge state information, and outputting electric braking power, wherein the electric braking power comprises in-cylinder braking power, so as to control the electric braking subsystem. Specifically, as shown in fig. 6, at time T1, it is determined that the battery is fully charged according to the acquired preset charge threshold, and the electric braking force output at this time is T2, which includes only the motor braking torque.

In some embodiments, the vehicle is controlled to descend at a first vehicle speed even speed when the electric braking power is greater than or equal to the required braking power. For example, a speed V0 shown in fig. 7 is taken as the first vehicle speed. The vehicle control unit can also receive vehicle speed information, charge state information and the like, and obtain required braking power according to the vehicle speed and gradient information. Specifically, in a long-slope descending mode, the vehicle control unit obtains electric braking power according to the motor power and/or in-cylinder braking power, and calculates the braking power required by the vehicle according to the vehicle speed and slope information. And comparing the electric braking power with the required braking power, and when the requirement of the whole vehicle on the braking force is determined to be not large, the whole vehicle controller only controls the electric braking subsystem to work, namely the electric braking subsystem outputs the electric braking torque completely to provide the braking force, and controls the balance between the electric braking force and the gliding force so as to realize that the vehicle is controlled to descend at the first vehicle speed and the uniform speed on the slope, wherein the time period of 0-t1 shown in fig. 6 is the process of descending at the first vehicle speed and the uniform speed.

In other embodiments, when the electric braking power is smaller than the required braking power, the mechanical braking subsystem is controlled to act according to the opening signal of the braking pedal, specifically, as shown in fig. 6, after the storage battery is fully charged at time t1, the in-cylinder braking torque is reduced, the electric braking torque is reduced, at this time, the electric braking power is smaller than the required braking power, the electric braking torque cannot meet the requirement, the vehicle speed is gradually increased, and at this time, the driver is required to step on the braking pedal of the vehicle to brake. During the time period t2-t4 shown in fig. 6 and 7, when the driver depresses the vehicle brake pedal, the mechanical braking subsystem is activated to output a mechanical braking torque, and the electric braking is coordinated with the mechanical braking to control the vehicle to decelerate until the braking torque provided meets the grade and speed requirements.

In other embodiments, when it is determined that the vehicle speed is less than the preset vehicle speed, a new required braking power is obtained based on the vehicle speed and the gradient information until the electric braking power and the mechanical braking power meet the new required braking power, and the vehicle is controlled to descend at a second vehicle speed with a uniform speed, for example, at a speed V1 shown in fig. 7 as the second vehicle speed, and after the electric braking is matched with the mechanical braking, the electric braking power and the mechanical braking power are equal to the new required braking power, thereby ensuring that the vehicle can travel at the second vehicle speed, thereby descending at the uniform speed.

In some embodiments, the relationship between the vehicle braking torque and speed over time in the time period t4-t9 shown in fig. 6 and 7 is the distribution of the electric braking and the mechanical braking in the deceleration braking mode, which is not described herein.

In some embodiments of the present invention, as shown in fig. 8, which is a flowchart of a vehicle braking control method according to still another embodiment of the present invention, the vehicle braking control method includes steps S201 to S214 in the downhill mode, as follows.

S201, the driver presses the downhill start button.

And S202, starting the electric brake.

And S203, judging the SOC state of the vehicle storage battery, namely determining the SOC state of the storage battery according to the SOC information.

And S204, determining that the storage battery is in a charging state.

And S205, outputting the motor power and the in-cylinder braking power to control the electric braking subsystem to brake until the step S206 is reached and the storage battery is fully charged.

And S207, the SOC of the storage battery is 100 percent, namely the storage battery is fully charged.

And S208, outputting in-cylinder braking power to control the electric braking subsystem to brake.

And S209, acquiring vehicle speed information.

And S210, acquiring gradient information.

And S211, the vehicle control unit calculates the braking power required by the speed when going downhill.

S212 determines whether the power satisfies the braking requirement, if yes, step S213 is executed, and if no, step S214 is executed.

And S213, determining that the power meets the requirement, and performing uniform downhill, namely controlling the vehicle to perform uniform downhill at the first vehicle speed on the slope.

S214, determining that the power can not meet the braking requirement, stepping a brake pedal by a driver, outputting mechanical braking force, and restarting braking power meter extreme after the vehicle speed is reduced until the ramp is driven downhill at a constant speed.

According to the vehicle brake control method provided by the embodiment of the invention, in a vehicle downhill slope mode, the vehicle control unit determines the braking power required by the vehicle according to the vehicle speed, the slope information and the charge state information, adopts electric braking or electromechanical combined braking according to the braking power required by the vehicle, adopts an optimization method, and calculates the optimal electric braking force with the aim of maximizing the braking energy feedback efficiency, so that the braking energy efficiency can be ensured, the maximization of braking energy recovery can be realized, and the coordinated control of electric braking and mechanical braking can be realized.

In some embodiments of the present invention, a braking system 10 is also proposed, as shown in fig. 9, which is a block diagram of a braking system according to an embodiment of the present invention, wherein the braking system 10 includes a mechanical braking subsystem 1, an electric braking subsystem 2 and an anti-lock braking subsystem 3, a brake pedal opening degree detection unit 4, a vehicle speed sensor 5, a battery manager 6, a gradient sensor 7 and a vehicle controller 8.

The mechanical braking subsystem 1 includes a power driving assembly and a braking actuator (not shown in the figure), the power driving assembly is electrically connected to the vehicle control unit 8, and the power driving assembly is mechanically connected to the braking actuator, so as to implement mechanical braking of the vehicle 100. The power drive assembly may be driven by a liquid or a gas, and may include, for example, various components and conduits for transmitting energy to brake actuators, such as brakes, master cylinders, wheel cylinders, and connecting conduits, which generate forces that oppose movement or tendencies of movement of the vehicle. When the vehicle 100 is mechanically braked, the power drive assembly transmits energy to the brakes, which rub against the wheels to prevent rotation or tendency of rotation of the wheels, and convert the kinetic energy of the motion of the vehicle 100 into frictional heat energy and release it to the atmosphere, thereby effecting mechanical braking.

The electric brake subsystem 2 includes a motor and a motor controller (not shown in the figure), the motor controller is connected with the motor, the motor controller is connected with the vehicle controller 8, and the electric brake adopts a braking principle that the motor outputs a back-dragging torque to brake the vehicle 100. Specifically, when the vehicle 100 is electrically braked, the motor controller controls the motor to run in a reverse-trailing mode, so that the motor is converted into a generator, that is, the motor brakes the vehicle 100 by using a back electromotive force, and energy generated during braking is converted into electric energy to be stored in the storage battery 20, so that braking energy recovery is realized.

The anti-lock braking subsystem 3 is an active safety system in the vehicle 100 that prevents wheel lock-up during emergency braking of the vehicle 100.

The brake pedal opening degree detection unit 4 is configured to detect an opening degree signal of a brake pedal of the vehicle, where the brake pedal opening degree detection unit 4 may be a sensor or the like, and obtains the opening degree signal of the brake pedal of the vehicle according to the brake pedal opening degree.

The vehicle speed sensor 5 may be provided at a wheel for detecting a vehicle speed.

The battery manager 6 is used to collect state of charge information of the vehicle battery 20. The State of charge information may be a State of charge (SOC) of the battery, which is used to reflect a remaining capacity of the battery, and is numerically defined as a ratio of the remaining capacity to the battery capacity, and is usually expressed by a percentage, and the value of the percentage is in a range of 0 to 100%, for example, when the SOC is 0, the SOC indicates that the battery is completely discharged, and when the SOC is 100%, the SOC indicates that the battery is completely charged.

The gradient sensor 7 is used to detect gradient information of a road on which the vehicle is traveling.

The vehicle control unit 8 is connected with the mechanical brake subsystem 1, the anti-lock brake subsystem 3, the electric brake subsystem 2, the brake pedal opening degree detection unit 4, the vehicle speed sensor 5, the battery manager 6 and the gradient sensor 7, and is used for controlling the mechanical brake subsystem 1, the anti-lock brake subsystem 3 and the electric brake subsystem 2 according to the vehicle brake control method of any one of the above embodiments.

Specifically, the vehicle controller 8 determines a braking mode of the vehicle 100, such as an emergency braking mode, a deceleration braking mode or a downhill mode, according to an opening signal of a vehicle brake pedal, a vehicle speed, charge state information of the vehicle battery 20 and gradient information of a road on which the vehicle runs, and controls an operation state of the mechanical braking subsystem 1 and/or the electrical braking subsystem 2 according to control strategies in different braking modes, so as to effectively coordinate and control electrical braking and mechanical braking. And in an emergency braking mode, when the depth of a vehicle brake pedal is continuously increased to a certain degree, the anti-lock braking subsystem 3 can be automatically started, after the vehicle control unit 8 detects a starting signal of the anti-lock braking subsystem 3, the electric braking subsystem 2 is controlled to quit the anti-drag operation, and the mechanical braking subsystem 1 outputs mechanical braking torque completely to brake the vehicle, so that the safety of a driver is ensured, and the stability and the braking efficiency of the vehicle are ensured.

According to the braking system 10 provided by the embodiment of the invention, the vehicle control unit 8 controls the operation state of the mechanical braking subsystem 1 and/or the electric braking subsystem 2 according to the opening degree signal of the vehicle brake pedal, the vehicle speed, the charge state information of the vehicle storage battery 20 and the gradient information of the vehicle running road, and coordinates and controls the electric braking and the mechanical braking in an emergency braking mode, a deceleration braking mode or a long-slope descending mode, so as to realize the vehicle braking control method of any one of the above embodiments, thereby ensuring the braking energy efficiency of the braking system 10 and maximizing the recovery of the braking energy.

In some embodiments of the present invention, as shown in fig. 10, which is a block diagram of a braking system according to an embodiment of the present invention, the braking system 10 further includes a downhill slope mode starting unit 9, and the downhill slope mode starting unit 9 is connected to the vehicle control unit 8, and is configured to receive an operation instruction for starting the downhill slope mode.

The long-slope mode starting unit 9 may include a downhill starting button, the driver presses the downhill starting button to send an operation instruction for starting the long-slope descending mode, and the vehicle controller 8 may recognize the long-slope descending intention of the driver according to the starting instruction of the long-slope descending mode, so as to control the vehicle to enter the long-slope descending mode.

In some embodiments of the present invention, a vehicle 100 is also provided, as shown in fig. 11, which is a block diagram of a vehicle according to an embodiment of the present invention, the vehicle 100 includes a battery 20 and the brake system 10 of any one of the above embodiments, wherein the battery 20 is connected with the electric brake subsystem 2 of the brake system 10. Vehicle 100 comprises, among other things, a heavy-duty, electric commercial vehicle.

Specifically, when the electric brake subsystem 2 operates to output an electric brake torque, the motor controller in the electric brake subsystem 2 controls the motor to perform a back-dragging operation, so that the motor is converted into a generator, i.e., the motor brakes the vehicle 100 by using a back electromotive force, and energy generated during braking is converted into electric energy to be stored in the storage battery 20, thereby realizing braking energy recovery.

According to the vehicle 100 provided by the embodiment of the invention, the braking system 10 comprising the mechanical braking subsystem 1 and the electric braking subsystem 2 is arranged in the vehicle 100, electromechanical composite braking can be realized, the vehicle braking control method of any one of the embodiments is adopted for control, when the vehicle 100 is braked, an optimization method is adopted, the optimal electric braking force is calculated in each braking mode with the aim of maximizing the braking energy feedback efficiency, and the distributed electric braking force is sent to the electric braking subsystem 2, so that the coordinated control of the electric braking and the mechanical braking is realized, the braking energy efficiency can be ensured, and the maximization of the braking energy recovery can be realized.

Other configurations and operations of the vehicle 100 according to embodiments of the present invention are known to those of ordinary skill in the art and will not be described in detail herein.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.