CN110843748A - Electronic hydraulic braking system and braking method - Google Patents
Electronic hydraulic braking system and braking method Download PDFInfo
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- CN110843748A CN110843748A CN201910843791.7A CN201910843791A CN110843748A CN 110843748 A CN110843748 A CN 110843748A CN 201910843791 A CN201910843791 A CN 201910843791A CN 110843748 A CN110843748 A CN 110843748A
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- stroke
- push rod
- output power
- pedal push
- hydraulic piston
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/58—Combined or convertible systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
- B60T13/741—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on an ultimate actuator
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Braking Systems And Boosters (AREA)
Abstract
The embodiment of the invention discloses an electronic hydraulic brake system and a brake method. The electro-hydraulic brake system includes: the electronic booster acquires the stroke of the pedal push rod in real time and converts the stroke of the pedal push rod into boosting output power; and driving the hydraulic piston according to the stroke of the pedal push rod and the power-assisted output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, the hydraulic piston is driven by the motor; when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively. The embodiment of the invention ensures that the pedal has larger feedback force when the pedal is deeper, realizes the limitation of the pedal stroke, solves the problem of overlarge pedal stroke in the conventional braking system, can give more obvious pedaling braking experience to a driver, and optimizes the experience of the driver on the pedal feeling.
Description
Technical Field
The embodiment of the invention relates to an electronic braking technology, in particular to an electronic hydraulic braking system and a braking method.
Background
With the increasing demands of consumers on the comfort, safety and economy of automobiles, more electromechanical products appear in the field of automobile braking.
The electronic booster based on the decoupling scheme simulates pedal feel through a pedal spring, and then utilizes the electronic booster to push a hydraulic piston according to the stroke of a pedal push rod, so that hydraulic braking corresponding to the stroke of the pedal push rod is realized. The electronic booster of the decoupling scheme is becoming mainstream design, and has natural advantages compared with the traditional vacuum booster on accelerating the build-up pressure rate, improving the energy recovery rate of the whole vehicle and realizing more advanced automatic driving functions.
However, for the electronic booster adopting the scheme of decoupling the pedal push rod and the master cylinder hydraulic piston, the stroke of the hydraulic piston is calculated by software according to the stroke of the pedal push rod, when a driver steps on the pedal, the pedal easily reaches a deep position, and the stroke of the pedal push rod is too large. Particularly in a vehicle stationary state, the pedal limit is far for a driver, and the experience during braking is easily reduced.
Disclosure of Invention
The invention provides an electronic hydraulic brake system and a brake method, which aim to limit the maximum stroke of a pedal push rod and solve the problem of overlong stroke of the pedal push rod.
In a first aspect, an embodiment of the present invention provides an electronic hydraulic brake system, including:
a hydraulic master cylinder in which a brake fluid is accommodated;
a hydraulic piston provided in the hydraulic master cylinder, the hydraulic piston being for pushing the brake fluid to output a braking force;
one end of the pedal push rod extends into the hydraulic main cylinder, and the other end of the pedal push rod is connected with a brake pedal;
the electronic booster acquires the stroke of a pedal push rod in real time and converts the stroke of the pedal push rod into boosting output power; the hydraulic piston is driven according to the stroke of the pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, a hydraulic piston is driven by a motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively.
Optionally, there is a friction force between the hydraulic piston and the hydraulic master cylinder.
Optionally, the electronic booster includes an electronic control unit, a pedal push rod travel sensor and a motor, and the electronic control unit is electrically connected to the pedal travel sensor and the motor respectively;
the pedal stroke sensor is used for collecting the stroke of the pedal push rod, and the electric control unit is used for controlling the motor to drive the hydraulic piston according to the stroke of the pedal push rod.
Optionally, the electronic control unit is further configured to receive a vehicle state signal, where the vehicle state includes a stationary state and a moving state.
Optionally, the electronic control unit is configured to compare the boost output power with a preset maximum boost output power when a stationary state signal of the vehicle is received; wherein the pedal push rod stroke when the power-assisted output power is equal to the maximum power-assisted output power is smaller than the decoupling stroke;
the electronic control unit is further used for driving the hydraulic piston with the boosting output power through a motor when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is smaller than the maximum boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is larger than or equal to the maximum boosting output power, a motor drives a hydraulic piston with the maximum boosting output power;
and when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, driving the hydraulic piston through the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the maximum boosting output power.
Optionally, the electronic control unit is configured to compare the boost output power with a preset maximum boost output power when a stationary state signal of the vehicle is received; wherein the pedal push rod stroke when the boost output power is equal to the maximum boost output power is greater than or equal to the decoupling stroke;
the electronic control unit is also used for driving the hydraulic piston by the aid of the power output power through a motor when the stroke of the pedal push rod is smaller than the decoupling stroke; when the pedal push rod stroke is greater than or equal to the decoupling stroke, driving the hydraulic piston through the pedal push rod and the motor, wherein when the boosting output power is less than the maximum boosting output power, the motor drives the hydraulic piston with the boosting output power; when the boosting output power is larger than or equal to the maximum boosting output power, the motor drives the hydraulic piston with the maximum boosting output power.
In a second aspect, an embodiment of the present invention further provides an electronic hydraulic braking method, including:
acquiring the stroke of a pedal push rod in real time, and converting the stroke of the pedal push rod into power-assisted output power;
driving the hydraulic piston according to the stroke of the pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, a hydraulic piston is driven by a motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively.
Optionally, before obtaining the brake pedal stroke in real time, the method further comprises:
and judging the current vehicle state, wherein the vehicle state comprises a static state and a motion state.
Optionally, if the current vehicle state is a stationary state, before driving the hydraulic piston according to the pedal push rod formation and the boosting output power, the method further includes:
comparing the power-assisted output power with a preset maximum power-assisted output power; wherein the pedal push rod stroke when the power-assisted output power is equal to the maximum power-assisted output power is smaller than the decoupling stroke;
when the footboard push rod stroke is less than the decoupling zero stroke, through motor drive hydraulic piston, include:
when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is smaller than the maximum boosting output power, driving the hydraulic piston with the boosting output power through a motor; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is larger than or equal to the maximum boosting output power, a motor drives a hydraulic piston with the maximum boosting output power;
when the pedal push rod stroke is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, and the hydraulic piston decoupling mechanism comprises:
driving the hydraulic piston via the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the maximum power assist output power.
Optionally, if the current vehicle state is a stationary state, before driving the hydraulic piston according to the pedal push rod formation and the boosting output power, the method further includes:
comparing the power-assisted output power with a preset maximum power-assisted output power; wherein the pedal push rod stroke when the boost output power is equal to the maximum boost output power is greater than or equal to the decoupling stroke;
when the footboard push rod stroke is less than the decoupling stroke, through motor drive hydraulic piston, include:
driving the hydraulic piston with the boosting output power through a motor;
when the pedal push rod stroke is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, and the hydraulic piston decoupling mechanism comprises:
driving the hydraulic piston by the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the boost output power when the boost output power is less than the maximum boost output power; when the boosting output power is larger than or equal to the maximum boosting output power, the motor drives the hydraulic piston with the maximum boosting output power.
The electronic hydraulic brake system provided by the embodiment of the invention is provided with a hydraulic main cylinder, a hydraulic piston, a pedal push rod and an electronic booster, wherein the hydraulic main cylinder is used for accommodating brake fluid, the hydraulic piston is arranged in the hydraulic main cylinder and used for pushing and pressing the brake fluid to output braking force, one end of the pedal push rod extends into the hydraulic main cylinder, the other end of the pedal push rod is connected with a brake pedal, and the electronic booster is used for acquiring the stroke of the pedal push rod in real time and converting the stroke of the pedal push rod into boosting output power; the hydraulic piston is driven according to the stroke of a pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, a hydraulic piston is driven by a motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, so that the pushing force of the hydraulic piston is divided into two situations according to the stroke of the pedal push rod, and meanwhile, the feedback force of the pedal is divided into two situations. The embodiment of the invention ensures that the pedal has larger feedback force when the pedal is deeper, realizes the limitation of the pedal stroke, solves the problem of overlarge pedal stroke in the conventional braking system, can give more obvious pedaling braking experience to a driver, and optimizes the experience of the driver on the pedal feeling.
Drawings
FIG. 1 is a schematic structural diagram of an electro-hydraulic brake system provided in accordance with an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of two pedal push rod strokes provided by the embodiment of the invention;
FIG. 3 is a schematic diagram of two structural forces of pedal push rod travel according to the embodiment of the present invention;
FIG. 4 is a graphical illustration of pedal feedback force versus pedal push rod travel for three electro-hydraulic brake systems;
FIG. 5 is a schematic structural diagram of another electro-hydraulic brake system provided by an embodiment of the present invention;
FIG. 6 is a schematic diagram of another three pedal push rod strokes provided by the present invention;
FIG. 7 is a schematic diagram of three pedal push rod strokes provided by an embodiment of the present invention;
FIG. 8 is a flow chart of an electro-hydraulic braking method provided by an embodiment of the present invention;
FIG. 9 is a flow chart of another electro-hydraulic braking method provided by an embodiment of the present invention;
fig. 10 is a flowchart of another electro-hydraulic braking method according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying 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 further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of an electronic hydraulic brake system according to an embodiment of the present invention, and referring to fig. 1, the electronic hydraulic brake system includes a hydraulic master cylinder 10, and a brake fluid 11 is contained in the hydraulic master cylinder 10; a hydraulic piston 20, the hydraulic piston 20 being provided in the hydraulic master cylinder 10, the hydraulic piston 20 being used to press the brake fluid 11 output for braking; a pedal push rod 30, one end of the pedal push rod 30 extending into the hydraulic master cylinder 10, and the other end connected with a brake pedal (not shown in the figure); the electronic booster 40 acquires the stroke of the pedal push rod in real time, and converts the stroke of the pedal push rod into boosting output power; and drives the hydraulic piston 20 according to the stroke of the pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke H, the hydraulic piston 20 is driven by the motor 41; when the stroke of the pedal push rod is greater than or equal to the decoupling stroke H, the hydraulic piston 20 is driven by the pedal push rod 30 and the motor 41; the decoupling stroke H is the distance between the pedal push rod 30 and the hydraulic piston 20 in the natural state.
The hydraulic braking system is characterized in that a hydraulic piston 20 is arranged in a hydraulic master cylinder 10, and the hydraulic piston 20 pushes brake fluid 11 to generate braking force to brake wheels. The pedal push rod 30 is a torque transmission rod directly connected to the pedal, and can indicate a pedal stroke and transmit a pedal force of the driver. The electronic booster 40 is responsible for acquiring the real-time stroke of the pedal push rod 30 and comparing the pedal push rod stroke with a decoupling stroke H prestored in the electronic booster 40 in real time. The decoupling stroke H is a distance between the pedal push rod 30 and the hydraulic piston 20 in a non-acting state, i.e., a natural state. The thrust to the hydraulic piston 20 here is divided into two cases according to the pedal push rod stroke, including a pedal push rod stroke less than the decoupling stroke H and a pedal push rod stroke greater than or equal to the decoupling stroke H. Fig. 2 is a schematic structural diagram of two pedal push rod strokes provided by an embodiment of the present invention, referring to a) of fig. 2, when the pedal push rod stroke D is smaller than the decoupling stroke H, at this time, the pedal push rod 30 does not contact the hydraulic piston 20, the electronic booster 40 is responsible for converting the pedal push rod stroke into boosting output power, and the hydraulic piston 20 is driven by the motor 41 with the boosting output power, so as to perform hydraulic braking by the hydraulic piston 20. The hydraulic braking is now completed entirely by the assistance of the electronic booster 40, and the pedal feedback force is provided only by a spring structure (not shown) provided on the pedal. Referring to b) of fig. 2, when the pedal push rod stroke D is greater than or equal to the decoupling stroke H, the pedal push rod 30 is in contact with the hydraulic piston 20, that is, the pedal push rod 30 can directly transmit the pedaling force to the hydraulic piston 20, and the pedal push rod 30 and the motor 41 of the electronic booster 40 simultaneously provide the pushing force to the hydraulic piston 20. On the contrary, the pedal push rod 30 receives the reverse hydraulic pressure force of the hydraulic piston 20, that is, when the driver treads deeply, the pedal can generate the feedback force which is in an exponential relation with the pedal stroke, so that the pedal stroke can be limited, the pedal stroke is avoided being too large, and the pedal brake experience of the driver is ensured. It should be noted that the braking logic of the electronic hydraulic braking system depends on the decoupling stroke, i.e. the structural distance between the pedal push rod 30 and the hydraulic piston 20, and those skilled in the art can set the decoupling stroke according to the actual pedaling experience of the driver and the actual structure of the hydraulic master cylinder, the hydraulic piston and the pedal push rod, which is not limited herein.
The electronic hydraulic brake system provided by the embodiment of the invention is provided with a hydraulic main cylinder, a hydraulic piston, a pedal push rod and an electronic booster, wherein the hydraulic main cylinder is used for accommodating brake fluid, the hydraulic piston is arranged in the hydraulic main cylinder and used for pushing and pressing the brake fluid to output braking force, one end of the pedal push rod extends into the hydraulic main cylinder, the other end of the pedal push rod is connected with a brake pedal, and the electronic booster is used for acquiring the stroke of the pedal push rod in real time and converting the stroke of the pedal push rod into boosting output power; and driving the hydraulic piston according to the stroke of the pedal push rod and the power-assisted output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, the hydraulic piston is driven by the motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, so that the driving force of the hydraulic piston is divided into two situations according to the stroke of the pedal push rod, and the feedback force of the pedal is divided into two situations. The embodiment of the invention ensures that the pedal has larger feedback force when the pedal is deeper, realizes the limitation of the pedal stroke, solves the problem of overlarge pedal stroke in the conventional braking system, can give more obvious pedaling braking experience to a driver, and optimizes the experience of the driver on the pedal feeling.
Due to the characteristic of the pedal spring, the pedal feedback force is basically consistent in the pedal stepping (going stroke) and pedal releasing (returning stroke) processes, and the hydraulic hysteresis effect of the traditional vacuum booster cannot be realized. In view of this, in the electronic hydraulic brake system according to the embodiment of the present invention, a friction force may exist between the hydraulic piston 20 and the hydraulic master cylinder 10. Fig. 3 is a schematic diagram of structural stress of two pedal push rod strokes provided by an embodiment of the present invention, referring to a) diagram of fig. 3, when the pedal push rod stroke is smaller than the decoupling stroke, the pedal push rod 30 is not in contact with the hydraulic piston 20, the hydraulic piston 20 is braked by the thrust of the motor 41 of the electronic booster, the feedback force of the pedal is equal to the pedal spring force, and the feedback force of the pedal at the same pedal push rod stroke during the forward stroke and the return stroke is the same. Referring to D) and e) of fig. 3, when the pedal push rod stroke D is greater than or equal to the decoupling stroke H, at which time the pedal push rod 30 contacts the hydraulic piston 20, the hydraulic piston 20 is braked by the motor of the electronic booster and the pedal force, and the pedal feedback force mainly includes a part of the hydraulic feedback force of the hydraulic piston and the pedal spring force. In addition, since there is a frictional force between the hydraulic piston 20 and the hydraulic master cylinder 10, there is a difference in frictional force between the forward stroke and the backward stroke. Specifically, during the forward stroke, referring to the graph b) in fig. 3, the pedal feedback force is the hydraulic feedback force + the pedal spring force + the friction force-the assisting force of the electronic booster; referring to the graph of fig. 3 c), the pedal feedback force is hydraulic feedback force + pedal spring force-friction force-electric booster assist force. Obviously, when the pedal goes away and returns, the feedback force has obvious difference, and certain friction force exists for blocking, so that the reaction of the pedal is delayed, and the delayed effect is formed.
Fig. 4 is a graph of a relationship between pedal feedback force and pedal push rod stroke of three electronic hydraulic brake systems, where curves 1 and 2 respectively show a relationship between pedal feedback force and pedal push rod stroke during forward stroke and return stroke of an electronic hydraulic brake system provided in an embodiment of the present invention, curves 3 and 4 respectively show a relationship between pedal feedback force and pedal push rod stroke during forward stroke and return stroke of a conventional vacuum-assisted hydraulic brake system, and curves 5 and 6 respectively show a relationship between pedal feedback force and pedal push rod stroke during forward stroke and return stroke of an electronic hydraulic brake system using only a decoupling scheme. As can be seen from fig. 4, the pedal feedback force of the conventional electronic hydraulic brake system is linearly related to the pedal push rod stroke, which illustrates that there is no significant difference in the deep and shallow pedaling process of the driver. In the electronic hydraulic brake system provided by the embodiment of the invention, the pedal feedback force and the pedal push rod form an exponential relationship, and when the pedal is deeply stepped, the pedal can generate obvious feedback force to limit the maximum stroke of the pedal, so that a driver can obviously feel the feedback of the pedal. In addition, the electronic hydraulic brake system provided by the embodiment of the invention has a slightly higher going curve than a returning curve, namely, the pedal has smaller feedback force during returning. In other words, the driver may clearly experience less feedback on the return stroke than on the forward stroke, with a hysteresis effect on the pedal.
Fig. 5 is a schematic structural diagram of another electronic hydraulic brake system provided in the embodiment of the present invention, and referring to fig. 5, specifically, the electronic booster 40 includes an electronic control unit 42, a pedal push rod stroke sensor 43 and a motor 41, and the electronic control unit 42 is electrically connected to the pedal stroke sensor 43 and the motor 41 respectively; the pedal stroke sensor 43 is used for acquiring the stroke of a pedal push rod, and the electronic control unit 42 is used for controlling the motor 41 to drive the hydraulic piston 20 according to the stroke of the pedal push rod.
The braking requirement is different in view of the fact that the braking force required in the stationary state of the vehicle is smaller than in the running state. With continued reference to FIG. 5, the electronic control unit 42 is also configured to receive a vehicle status signal, the vehicle status signal including a stationary status and a moving status. Fig. 6 is a schematic structural diagram of three pedal push rod strokes provided by the embodiment of the present invention, specifically, the electronic control unit 42 is configured to compare the boost output power with the preset maximum boost output power when receiving the stationary state signal of the vehicle; and the stroke L of the pedal push rod when the boosting output power is equal to the maximum boosting output power is smaller than the decoupling stroke H. Referring to fig. 5 and a) of fig. 6, when the pedal push rod stroke D is smaller than the decoupling stroke H and the assisting output power is smaller than the maximum assisting output power, at this time, the pedal push rod stroke D is smaller than L, the electronic control unit 42 controls the motor 41 to drive the hydraulic piston with the assisting output power; referring to fig. 5 and b) of fig. 6, when the pedal push rod stroke D is smaller than the decoupling stroke H and the assisting output power is greater than or equal to the maximum assisting output power, at this time, the pedal push rod stroke D is greater than or equal to L, and the electronic control unit 42 controls the motor 41 to drive the hydraulic piston with the maximum assisting output power; referring to fig. 5 and c) of fig. 6, when the pedal push rod stroke D is greater than or equal to the decoupling stroke H, the electronic control unit 42 controls the motor 41 to drive the hydraulic piston 20, and the pedal push rod also pushes the hydraulic piston 20. Wherein the motor drives the hydraulic piston 20 with maximum power assistance output.
FIG. 7 is a schematic diagram of three pedal push rod strokes, wherein the electronic control unit 42 is configured to compare the boost output power with a preset maximum boost output power when receiving a stationary state signal of the vehicle; and when the boosting output power is equal to the maximum boosting output power, the stroke L of the pedal push rod is greater than or equal to the decoupling stroke H. Referring to fig. 5 and a) of fig. 7, when the pedal push rod stroke D is smaller than the decoupling stroke H, the electronic control unit 42 controls the motor 41 to drive the hydraulic piston 20 with the boosting output power; when the pedal push rod stroke D is greater than or equal to the decoupling stroke H, the hydraulic piston 20 is driven by the pedal push rod 30 and the motor 41, wherein, referring to b) diagrams of fig. 5 and 7, when the boosting output power is less than the maximum boosting output power, the pedal push rod stroke D is less than L at this time, the electric control unit 42 controls the motor 41 to drive the hydraulic piston 20 with the boosting output power; referring to fig. 5 and c) of fig. 7, when the assist output power is greater than or equal to the maximum assist output power, at which the pedal push rod stroke D is greater than or equal to L, the electronic control unit 42 controls the motor 41 to drive the hydraulic piston 20 at the maximum assist output power.
It should be noted that the maximum power-assisted output power value is manually set according to the actual braking requirement, and the decoupling stroke is determined during the structural design, so that the pedal push rod stroke L corresponding to the maximum power-assisted output power has a size relationship with the decoupling stroke H. Preferably, in order to ensure the smoothness of the change of the pedal feedback force, that is, to avoid that the assisting output power of the electronic booster is not changed due to the change of the stroke D of the pedal push rod when the pedal push rod is not in contact with the hydraulic piston, or to avoid that the assisting output power of the electronic booster is still changed after the pedal push rod is in contact with the hydraulic piston, the stroke L of the pedal push rod when the assisting output power is equal to the maximum assisting output power may be set to be equal to the decoupling stroke H, and at this time, after the pedal push rod is in contact with the hydraulic piston, the pedal feedback force further includes a hydraulic feedback force which is increased gradually from zero and has an exponential relationship with the stroke.
An embodiment of the present invention further provides an electronic hydraulic braking method, and fig. 8 is a flowchart of the electronic hydraulic braking method provided in the embodiment of the present invention, and referring to fig. 1 and fig. 8, the electronic hydraulic braking method may be applied to an electronic hydraulic braking system to implement a braking control logic in the electronic hydraulic system. The electronic hydraulic braking method comprises the following steps:
s110, acquiring the stroke of a pedal push rod in real time, and converting the stroke of the pedal push rod into power-assisted output power;
s120, driving a hydraulic piston according to the stroke of the pedal push rod and the power-assisted output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, the hydraulic piston is driven by the motor; when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively.
According to the electronic hydraulic braking method provided by the embodiment of the invention, the stroke of the pedal push rod is obtained in real time, and the stroke of the pedal push rod is converted into the boosting output power; then, according to the stroke of a pedal push rod and the power-assisted output power, a hydraulic piston is driven; when the stroke of the pedal push rod is smaller than the decoupling stroke, the hydraulic piston is driven by the motor; when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in the natural state, so that the pushing force of the hydraulic piston is divided into two situations according to the stroke of the pedal push rod, and the feedback force of the pedal is divided into two situations. The embodiment of the invention ensures that the pedal has larger feedback force when the pedal is deeper, realizes the limitation of the pedal stroke, solves the problem of overlarge pedal stroke in the conventional braking system, and can provide more obvious pedaling braking experience for a driver.
An embodiment of the present invention further provides an electronic hydraulic braking method, and fig. 9 is a flowchart of another electronic hydraulic braking method provided in the embodiment of the present invention, and with reference to fig. 5 and 9, the electronic hydraulic braking method includes:
s210, judging the current vehicle state, wherein the vehicle state comprises a static state and a motion state.
S220, if the current vehicle state is a static state, comparing the power-assisted output power with a preset maximum power-assisted output power; and the stroke of the pedal push rod when the boosting output power is equal to the maximum boosting output power is smaller than the decoupling stroke.
S230, driving a hydraulic piston according to the stroke of the pedal push rod and the power-assisted output power; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is smaller than the maximum boosting output power, the hydraulic piston is driven by the boosting output power through the motor; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is larger than or equal to the maximum boosting output power, the hydraulic piston is driven by the maximum boosting output power through the motor; and when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the maximum power-assisted output power.
Except the above-mentioned electronic hydraulic braking method, in step S220, the pedal push rod stroke is set to be smaller than the decoupling stroke when the boosting output power is equal to the maximum boosting output power. The travel of the pedal push rod when the boosting output power is equal to the maximum boosting output power can be set to be larger than or equal to the decoupling travel. Correspondingly, fig. 10 is a flowchart of another electrohydraulic braking method provided by the embodiment of the present invention, and referring to fig. 7 and 10, the electrohydraulic braking method includes:
and S310, judging the current vehicle state, wherein the vehicle state comprises a static state and a motion state.
S320, if the current vehicle state is a static state, comparing the power-assisted output power with a preset maximum power-assisted output power; and when the boosting output power is equal to the maximum boosting output power, the stroke of the pedal push rod is greater than or equal to the decoupling stroke.
S330, driving a hydraulic piston according to the stroke of the pedal push rod and the power-assisted output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, the hydraulic piston is driven by the power-assisted output power through the motor; when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, wherein when the boosting output power is less than the maximum boosting output power, the hydraulic piston is driven by the motor with the boosting output power; when the boosting output power is larger than or equal to the maximum boosting output power, the motor drives the hydraulic piston with the maximum boosting output power.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. An electro-hydraulic brake system, comprising:
a hydraulic master cylinder in which a brake fluid is accommodated;
a hydraulic piston provided in the hydraulic master cylinder, the hydraulic piston being for pushing the brake fluid to output a braking force;
one end of the pedal push rod extends into the hydraulic main cylinder, and the other end of the pedal push rod is connected with a brake pedal;
the electronic booster acquires the stroke of a pedal push rod in real time and converts the stroke of the pedal push rod into boosting output power; the hydraulic piston is driven according to the stroke of the pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, a hydraulic piston is driven by a motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively.
2. The electro-hydraulic brake system of claim 1, wherein a frictional force exists between the hydraulic piston and the hydraulic master cylinder.
3. The electro-hydraulic brake system of claim 1, wherein the electronic booster includes an electronic control unit, a pedal push rod stroke sensor, and a motor, the electronic control unit being electrically connected to the pedal stroke sensor and the motor, respectively;
the pedal stroke sensor is used for collecting the stroke of the pedal push rod, and the electric control unit is used for controlling the motor to drive the hydraulic piston according to the stroke of the pedal push rod.
4. The electro-hydraulic brake system of claim 3, wherein the electronic control unit is further configured to receive a vehicle status signal, the vehicle status signal including a stationary status and a moving status.
5. The electro-hydraulic brake system of claim 4, wherein the electronic control unit is configured to compare the boost output power to a preset maximum boost output power upon receipt of a stationary state signal of the vehicle; wherein the pedal push rod stroke when the power-assisted output power is equal to the maximum power-assisted output power is smaller than the decoupling stroke;
the electronic control unit is further used for driving the hydraulic piston with the boosting output power through a motor when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is smaller than the maximum boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is larger than or equal to the maximum boosting output power, a motor drives a hydraulic piston with the maximum boosting output power;
and when the stroke of the pedal push rod is greater than or equal to the decoupling stroke, driving the hydraulic piston through the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the maximum boosting output power.
6. The electro-hydraulic brake system of claim 4, wherein the electronic control unit is configured to compare the boost output power to a preset maximum boost output power upon receipt of a stationary state signal of the vehicle; wherein the pedal push rod stroke when the boost output power is equal to the maximum boost output power is greater than or equal to the decoupling stroke;
the electronic control unit is also used for driving the hydraulic piston by the aid of the power output power through a motor when the stroke of the pedal push rod is smaller than the decoupling stroke; when the pedal push rod stroke is greater than or equal to the decoupling stroke, driving the hydraulic piston through the pedal push rod and the motor, wherein when the boosting output power is less than the maximum boosting output power, the motor drives the hydraulic piston with the boosting output power; when the boosting output power is larger than or equal to the maximum boosting output power, the motor drives the hydraulic piston with the maximum boosting output power.
7. An electro-hydraulic braking method, comprising:
acquiring the stroke of a pedal push rod in real time, and converting the stroke of the pedal push rod into power-assisted output power;
driving the hydraulic piston according to the stroke of the pedal push rod and the boosting output power; when the stroke of the pedal push rod is smaller than the decoupling stroke, a hydraulic piston is driven by a motor; when the stroke of the pedal push rod is larger than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor; the decoupling stroke is the distance between the pedal push rod and the hydraulic piston in a natural state respectively.
8. The electro-hydraulic braking method according to claim 7, further comprising, before acquiring the brake pedal stroke in real time:
and judging the current vehicle state, wherein the vehicle state comprises a static state and a motion state.
9. The electro-hydraulic braking method of claim 8, further comprising, before driving the hydraulic piston according to the pedal push rod shape and the assist output power if the current vehicle state is a stationary state:
comparing the power-assisted output power with a preset maximum power-assisted output power; wherein the pedal push rod stroke when the power-assisted output power is equal to the maximum power-assisted output power is smaller than the decoupling stroke;
when the footboard push rod stroke is less than the decoupling zero stroke, through motor drive hydraulic piston, include:
when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is smaller than the maximum boosting output power, driving the hydraulic piston with the boosting output power through a motor; when the stroke of the pedal push rod is smaller than the decoupling stroke and the boosting output power is larger than or equal to the maximum boosting output power, a motor drives a hydraulic piston with the maximum boosting output power;
when the pedal push rod stroke is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, and the hydraulic piston decoupling mechanism comprises:
driving the hydraulic piston via the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the maximum power assist output power.
10. The electro-hydraulic braking method of claim 8, further comprising, before driving the hydraulic piston according to the pedal push rod shape and the assist output power if the current vehicle state is a stationary state:
comparing the power-assisted output power with a preset maximum power-assisted output power; wherein the pedal push rod stroke when the boost output power is equal to the maximum boost output power is greater than or equal to the decoupling stroke;
when the footboard push rod stroke is less than the decoupling stroke, through motor drive hydraulic piston, include:
driving the hydraulic piston with the boosting output power through a motor;
when the pedal push rod stroke is greater than or equal to the decoupling stroke, the hydraulic piston is driven by the pedal push rod and the motor, and the hydraulic piston decoupling mechanism comprises:
driving the hydraulic piston by the pedal push rod and the motor, wherein the motor drives the hydraulic piston with the boost output power when the boost output power is less than the maximum boost output power; when the boosting output power is larger than or equal to the maximum boosting output power, the motor drives the hydraulic piston with the maximum boosting output power.
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| CN201910843791.7A CN110843748A (en) | 2019-09-06 | 2019-09-06 | Electronic hydraulic braking system and braking method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910843791.7A CN110843748A (en) | 2019-09-06 | 2019-09-06 | Electronic hydraulic braking system and braking method |
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| CN110843748A true CN110843748A (en) | 2020-02-28 |
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Cited By (1)
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| CN115285093A (en) * | 2022-08-17 | 2022-11-04 | 上海拿森汽车电子有限公司 | Push rod zero-position self-learning method of electronic booster for automobile and electronic equipment |
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