CN118269908A - Brake-by-wire system and control method thereof - Google Patents
Brake-by-wire system and control method thereof Download PDFInfo
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- CN118269908A CN118269908A CN202211706822.2A CN202211706822A CN118269908A CN 118269908 A CN118269908 A CN 118269908A CN 202211706822 A CN202211706822 A CN 202211706822A CN 118269908 A CN118269908 A CN 118269908A
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- 238000001514 detection method Methods 0.000 claims abstract description 18
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- 238000003825 pressing Methods 0.000 claims abstract description 4
- 238000003860 storage Methods 0.000 claims abstract description 3
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Abstract
The invention provides a brake-by-wire system and a control method thereof. The brake-by-wire system comprises a pressure medium storage tank, a master cylinder, a brake pedal connected with the master cylinder, a travel detection unit for sensing the position change of the brake pedal, a pedal feel simulator, a brake cylinder, a hydraulic driving unit and an electric control unit, and further comprises an auxiliary circuit, wherein the auxiliary circuit is used for pressing brake fluid into the master cylinder by the aid of the hydraulic driving unit, an auxiliary circuit control valve for controlling the auxiliary circuit to be connected or disconnected is arranged on the auxiliary circuit, the electric control unit controls the operation of the hydraulic driving unit and the opening/closing of the auxiliary circuit control valve, and the master cylinder is not provided with a spring.
Description
Technical Field
The invention relates to the technical field of vehicle braking, in particular to a brake-by-wire system and a control method thereof.
Background
The brake system is an important guarantee for the running safety of the automobile, and with the development of the intellectualization of the automobile, the brake-by-wire system gradually replaces the traditional brake system and is widely applied. The conventional brake-by-wire system comprises a brake pedal, a brake master cylinder assembly, a pedal feel simulator, a brake wheel cylinder assembly and a motor, wherein the brake master cylinder assembly is connected with the pedal feel simulator through a simulator control valve, and the simulator control valve is a normally closed electromagnetic valve; the motor provides brake fluid for the brake cylinder assembly.
In the brake-by-wire system, a driver presses a brake pedal, a master cylinder push rod pushes a brake master cylinder piston, brake fluid and springs in the master cylinder are extruded, the brake fluid is pressed into a pedal feel simulator, springs and rubber parts in the brake fluid begin to be compressed, feedback force is generated for the push rod and the brake pedal, and the right foot of the driver obtains the feel of a traditional hydraulic brake pedal. As the pedal stroke of the driver's foot increases, the brake fluid further pushes against elements in the pedal feel simulator, creating a greater feedback force to the pedal, creating a conventional pedal force and displacement curve. As the driver's foot releases the pedal, the spring element in the simulator and the spring in the master cylinder begin to release the restoring force, eventually pushing the master cylinder push rod and pedal back to the original position.
The springs in the brake master cylinder are determined by pedal feel requirements of customers, different pedal feel of different customers can be matched by the different springs, and the variety, complexity and design cost of parts are increased in design.
Disclosure of Invention
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a brake-by-wire system and a control method thereof, which can reduce a brake master cylinder space and reduce costs without providing a spring in the brake master cylinder.
According to an aspect of the present invention, there is provided a brake-by-wire system including a pressure medium reservoir, a master cylinder, a brake pedal connected to the master cylinder, a stroke detection unit for sensing a change in position of the brake pedal to form a brake stroke signal, a pedal feel simulator, a brake cylinder, a hydraulic drive unit for supplying brake fluid to the brake cylinder, and an electric control unit, further including an auxiliary circuit for pressing the brake fluid into the master cylinder using the hydraulic drive unit, and the auxiliary circuit being provided with an auxiliary circuit control valve for controlling the connection or disconnection of the auxiliary circuit, the electric control unit controlling the operation of the hydraulic drive unit and the opening/closing of the auxiliary circuit control valve, the master cylinder being not provided with a spring.
Preferably, one end of the auxiliary circuit is connected to an output end of the hydraulic drive unit, and the other end is connected to a simulator chamber of the pedal feel simulator.
Preferably, the auxiliary circuit control valve is a normally closed valve.
Preferably, the hydraulic drive unit includes a motor and a linear actuator.
Preferably, the master cylinder is connected to the pedal feel simulator via a simulator valve, and the electronic control unit controls opening/closing of the simulator valve.
Preferably, the brake-by-wire system further comprises a first pressure sensor for detecting the master cylinder pressure and a second pressure sensor for detecting the pressure at the output of the hydraulic drive unit.
According to another aspect of the present invention, there is provided a control method of a brake-by-wire system, applied to the above brake-by-wire system, comprising the steps of: the electric control unit controls the hydraulic driving unit to work to build pressure under the condition that the brake pedal is released; when the pressures at the two sides of the auxiliary loop control valve reach balance, the electronic control unit opens the auxiliary loop control valve; and when the brake pedal is restored to the original position, the electric control unit controls the hydraulic driving unit to stop working and closes the auxiliary loop control valve.
Preferably, the electronic control unit senses whether the brake pedal is released based on a brake stroke signal of the stroke detection unit.
Preferably, the brake-by-wire system further comprises a first pressure sensor for detecting the pressure of the master cylinder and a second pressure sensor for detecting the pressure of the output end of the hydraulic driving unit, and the electric control unit judges whether the pressures at both sides of the auxiliary circuit control valve are balanced based on the detection results of the first pressure sensor and the second pressure sensor.
Preferably, the electronic control unit confirms whether the brake pedal is restored to the original position based on a brake stroke signal of the stroke detection unit.
Drawings
Fig. 1 is a schematic structural diagram of a linear brake system according to an embodiment of the present invention.
Fig. 2 is a flowchart of a control method of a linear brake system according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only a portion related to the present invention is shown in the drawings.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Embodiments described herein may be described with reference to plan and/or cross-sectional views with the aid of idealized schematic diagrams of the present disclosure. Accordingly, the example illustrations may be modified in accordance with manufacturing techniques and/or tolerances. Thus, the embodiments are not limited to the embodiments shown in the drawings, but include modifications of the configuration formed based on the manufacturing process. Thus, the regions illustrated in the figures have schematic properties and the shapes of the regions illustrated in the figures illustrate the particular shapes of the regions of the elements, but are not intended to be limiting.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Fig. 1 is a schematic structural diagram of a linear brake system according to an embodiment of the present invention.
As shown, the present embodiment provides a brake-by-wire system including: the brake system comprises a pressure medium storage tank 1, a master cylinder 2, a brake pedal 31 connected with the master cylinder, a stroke detection unit 22 for sensing a position change of the brake pedal to form a brake stroke signal, a pedal feel simulator 19, brake cylinders 4-7, a hydraulic drive unit 3 for supplying brake fluid to the brake cylinders, and an Electric Control Unit (ECU) 9.
The brake-by-wire system provided in this embodiment further includes an auxiliary circuit AB for pressing brake fluid into the master cylinder 2 using the hydraulic drive unit 3, and the auxiliary circuit AB is provided with an auxiliary circuit control valve 34 for controlling the connection or disconnection of the auxiliary circuit AB. In this embodiment, as shown in fig. 1, one end a of the auxiliary circuit AB is connected to the output end of the hydraulic drive unit 3, and the other end B is connected to the simulator chamber of the pedal feel simulator 19. The electronic control unit 9 controls the operation of the hydraulic drive unit 3 and the opening/closing of the auxiliary circuit control valve 19. Further, in the present embodiment, the master cylinder is not provided with a spring.
The pressure medium tank 1 is used for storing brake fluid. The master cylinder 2 may be actuated by a brake pedal 31. Specifically, the master cylinder 2 includes a cylinder body and a piston 32 slidably provided in the cylinder body. One end of the pedal transmission assembly 8 is connected to a brake pedal 31, and the other end is connected to a piston 32 of the master cylinder 2. When the driver steps on the brake pedal 31, the brake pedal 31 drives the piston of the master cylinder 2 to move in the cylinder body through the pedal transmission assembly 8, so that the brake fluid in the master cylinder 2 flows out to the valve, the structural member and the like connected with the brake fluid. The pedal transmission assembly may be a push rod, or may be other structures capable of transmitting power between the brake pedal 31 and the piston of the master cylinder 2.
The hydraulic drive unit 3 receives a control instruction of the electronic control unit 9 to supply brake fluid to the brake cylinders 4-7, causing the brake cylinders 4-7 to perform braking actions. The hydraulic drive unit 3 in this embodiment comprises a motor 18 and a linear actuator 17.
The electronic control unit 9 is electrically connected with the stroke detection unit 22, and the position change of the brake pedal 31 is sensed by the stroke detection unit 22 to form a brake stroke signal, and the electronic control unit 9 can receive the brake stroke signal of the stroke detection unit 22 to control the hydraulic pressure of the hydraulic driving unit 3 to build pressure and output proper braking force.
The master cylinder 2 is connected to a pedal feel simulator 19 via a simulator valve 13, and the electronic control unit 9 controls opening/closing of the simulator valve 13.
When the driver steps on the brake pedal 31, the electronic control unit 9 receives a brake stroke signal of the stroke detection unit 22, and opens the simulator valve 13. At this time, the pedal transmission assembly 8 pushes the piston 32, compresses the brake fluid in the master cylinder 2, and under the pressure, the brake fluid flows into the pedal feel simulator 19 through the simulator valve 13, and the pedal feel simulator 19 generates a feedback force to the pedal transmission assembly 8 and the brake pedal 31. Simultaneously, the motor 18 is started, the linear actuator 17 builds pressure, and brake fluid respectively enters four brake wheel cylinders 4-7 to brake the wheel cylinders, so that the vehicle generates deceleration.
Further, when the driver releases the brake pedal 31, the springs and elastic members in the pedal feel simulator 19 start to release the restoring force, pushing the piston 32 of the master cylinder and the pedal transmission assembly 8 to return. At this time, the electronic control unit 9 can sense that the brake pedal 31 is released based on the brake stroke signal of the stroke detection unit 22. In case the electronic control unit 9 senses that the brake pedal 31 is released, the hydraulic drive unit 3 is controlled to operate to build pressure, and when the pressure on both sides of the auxiliary circuit control valve 34 reaches equilibrium, the electronic control unit 9 opens the auxiliary circuit control valve 34. Then, the brake fluid flows into the simulator chamber of the pedal feel simulator 19 via the auxiliary circuit control valve 34 under the pressure of the hydraulic drive unit 3, and further flows into the master cylinder 2 via the simulator valve 13. Thereby, the restoring force can be increased, and the piston 32 of the auxiliary master cylinder and the pedal transmission assembly 8 return. With this design, even if the spring in the master cylinder 2 is eliminated, the lost restoring force can be compensated for by the auxiliary circuit AB.
In some embodiments, the brake-by-wire system further comprises a first pressure sensor 20 for detecting the master cylinder pressure and a second pressure sensor 21 for detecting the pressure at the output of the hydraulic drive unit 3. Thus, the brake-by-wire system can determine whether the pressures on both sides of the auxiliary circuit control valve 34 reach equilibrium or not by using the first pressure sensor 20 and the second pressure sensor 21 for controlling the opening/closing of the auxiliary circuit control valve 34.
Fig. 2 is a flowchart of a control method of a linear brake system according to an embodiment of the present invention. The control method of the linear braking system is applied to the linear braking system and comprises the following steps of:
s101: the electronic control unit 9 controls the hydraulic drive unit 3 to operate to build pressure in the case where it is sensed that the brake pedal 31 is released.
The electronic control unit 9 senses whether the brake pedal is released based on the brake stroke signal of the stroke detection unit 22. In case the electronic control unit 9 senses that the brake pedal 31 is released, the hydraulic drive unit 3 is controlled to operate to build pressure, i.e. the electronic control unit 9 starts the motor 18 and the linear actuator 17 builds pressure.
S102: when the pressure on both sides of the auxiliary circuit control valve 34 reaches equilibrium, the electronic control unit 9 opens the auxiliary circuit control valve 34.
In the case where the brake-by-wire system includes the first pressure sensor 20 for detecting the master cylinder pressure and the second pressure sensor 21 for detecting the pressure at the output end of the hydraulic drive unit 3, the electronic control unit 9 may determine whether the pressures on both sides of the auxiliary circuit control valve 34 are balanced based on the detection results of the first pressure sensor 20 and the second pressure sensor 21.
When the pressure on both sides of the auxiliary circuit control valve 34 reaches equilibrium, the electronic control unit 9 opens the auxiliary circuit control valve 34. Then, the brake fluid flows into the simulator chamber of the pedal feel simulator 19 via the auxiliary circuit control valve 34 under the pressure of the hydraulic drive unit 3, and further flows into the master cylinder 2 via the simulator valve 13. The brake fluid flowing into the master cylinder 2 through the simulator chamber can generate a restoring force that urges the piston 32 of the master cylinder and the pedal transmission assembly 8 to return to the original position to compensate for the restoring force lost without providing a spring in the master cylinder 2.
S103: when the brake pedal 31 is restored to the original position, the electronic control unit 9 controls the hydraulic drive unit 3 to stop operating, and closes the auxiliary circuit control valve 34.
After the driver releases the brake pedal 31, the restoring force released by the spring and the elastic member in the pedal feel simulator 19, and the brake fluid supplied by the high pressure of the hydraulic drive unit 3 further compensates the restoring force, so that the brake pedal 31 is restored to the original position. When the electronic control unit 9 confirms that the brake pedal 31 is restored to the original position based on the brake stroke signal of the stroke detection unit 22, the electronic control unit 9 controls the hydraulic drive unit 3 to stop operating and closes the auxiliary circuit control valve 34.
According to the invention, the auxiliary circuit and the auxiliary circuit control valve can be used for replacing the spring in the main cylinder, thereby reducing the space of the main cylinder and the design cost. In addition, according to the design of the invention, even after the parts of the whole vehicle are aged, more restoring force can be flexibly provided through the auxiliary circuit and the auxiliary circuit control valve.
Those of skill in the art will appreciate that the modules, elements, and method steps of a respective example described in connection with the embodiments disclosed herein may be preceded by electronic hardware, computer software, or a combination of both, and that the constituent elements and steps of the respective example have been generally described functionally in the foregoing description in order to clearly illustrate the interchangeability of electronic hardware and software. Whether such functionality is implemented as electronic hardware or software depends upon the particular application and design constraints imposed on the solution. Those skilled in the art may implement the described functionality using different approaches for each particular application, but such implementation is not to be considered as outside the scope of the present invention.
Although the present invention has been described with reference to the present specific embodiment, it should be appreciated by those skilled in the art that the scope of the invention is not limited to the specific combination of the above technical features, but encompasses other technical features formed by any combination of the above technical features or their equivalents without departing from the spirit of the invention. Such as the above-mentioned features and the technical features disclosed in the present invention (but not limited to) having similar functions are replaced with each other.
Claims (10)
1. A brake-by-wire system comprises a pressure medium storage tank, a master cylinder, a brake pedal connected with the master cylinder, a stroke detection unit for sensing the position change of the brake pedal to form a brake stroke signal, a pedal feel simulator, a brake wheel cylinder, a hydraulic driving unit for providing brake fluid for the brake wheel cylinder and an electric control unit, and is characterized in that,
And an auxiliary circuit for pressing brake fluid into the master cylinder using the hydraulic drive unit, and provided with an auxiliary circuit control valve for controlling the auxiliary circuit to be connected or disconnected,
The electric control unit controls the operation of the hydraulic driving unit and the opening/closing of the auxiliary circuit control valve,
The master cylinder is not provided with a spring.
2. A brake-by-wire system as defined in claim 1, wherein,
One end of the auxiliary circuit is connected to the output end of the hydraulic drive unit, and the other end is connected to the simulator cavity of the pedal feel simulator.
3. A brake-by-wire system as defined in claim 1, wherein,
The auxiliary loop control valve is a normally closed valve.
4. A brake-by-wire system as claimed in claim 1 or 2, characterized in that,
The hydraulic driving unit comprises a motor and a linear actuator.
5. A brake-by-wire system as claimed in claim 1 or 2, characterized in that,
The master cylinder is connected to the pedal feel simulator via a simulator valve, and the electronic control unit controls opening/closing of the simulator valve.
6. A brake-by-wire system as claimed in claim 1 or 2, characterized in that,
The hydraulic control system further comprises a first pressure sensor for detecting the master cylinder pressure and a second pressure sensor for detecting the pressure of the output end of the hydraulic drive unit.
7. A control method of a brake-by-wire system, applied to the brake-by-wire system according to any one of claims 1 to 5, comprising the steps of:
the electric control unit controls the hydraulic driving unit to work to build pressure under the condition that the brake pedal is released;
When the pressures at the two sides of the auxiliary loop control valve reach balance, the electronic control unit opens the auxiliary loop control valve; and
When the brake pedal is restored to the original position, the electronic control unit controls the hydraulic driving unit to stop working and closes the auxiliary loop control valve.
8. A control method of a brake-by-wire system as set forth in claim 7, wherein,
The electronic control unit senses whether the brake pedal is released based on a brake stroke signal of the stroke detection unit.
9. A control method of a brake-by-wire system according to claim 7 or 8,
The brake-by-wire system further comprises a first pressure sensor for detecting the pressure of the master cylinder and a second pressure sensor for detecting the pressure of the output end of the hydraulic driving unit, and the electric control unit judges whether the pressures at the two sides of the auxiliary loop control valve reach balance or not based on the detection results of the first pressure sensor and the second pressure sensor.
10. A control method of a brake-by-wire system according to claim 7 or 8,
The electronic control unit confirms whether the brake pedal is restored to an original position based on a brake stroke signal of the stroke detection unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211706822.2A CN118269908A (en) | 2022-12-29 | 2022-12-29 | Brake-by-wire system and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211706822.2A CN118269908A (en) | 2022-12-29 | 2022-12-29 | Brake-by-wire system and control method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN118269908A true CN118269908A (en) | 2024-07-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211706822.2A Pending CN118269908A (en) | 2022-12-29 | 2022-12-29 | Brake-by-wire system and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118269908A (en) |
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2022
- 2022-12-29 CN CN202211706822.2A patent/CN118269908A/en active Pending
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