KR102211825B1 - Active hydraulic booster system in vehice - Google Patents

Abstract

A vehicle's active hydraulic booster system is disclosed. An active hydraulic booster system for a vehicle according to an embodiment of the present invention includes a master cylinder, a reservoir coupled to the master cylinder to store brake fluid, a motor that drives a pump that pumps brake fluid from the reservoir, and is driven by the motor. A hydraulic flow path that guides the brake fluid to each wheel cylinder according to the operation of the pump, which is connected to the hydraulic flow path, and a backup flow path that guides the brake fluid of the master cylinder to each wheel cylinder according to the pedal effort of the brake pedal, and during sudden braking of the vehicle. And an electronic control unit that controls the pump to generate the first hydraulic pressure, and supplies the second hydraulic pressure and the first hydraulic pressure generated in the master cylinder to each wheel cylinder according to the pedal effort of the brake pedal.

Description

Vehicle active hydraulic booster system {ACTIVE HYDRAULIC BOOSTER SYSTEM IN VEHICE}

The present invention relates to an active hydraulic booster system for a vehicle, and to an active hydraulic booster system for a vehicle that generates hydraulic pressure using a motor and a pump to secure braking force.

The booster of the existing braking system is a device that creates a vacuum by being connected to the engine to help the driver with a vacuum when the driver brakes to create a large braking force. In the case of hybrid or electric vehicles, it is difficult to operate the booster at all times if the gasoline engine does not operate at all times or does not have sufficient vacuum. An active hydraulic booster (AHB) system to solve this problem is a system that directly generates hydraulic pressure using a motor and a pump instead of a booster, and secures a braking force through the hydraulic pressure.

The AHB system has a problem in that it is difficult to secure sufficient braking force to the wheels within a relatively short time in a sudden braking situation of a vehicle, so that the braking distance is long.

According to an embodiment of the present invention, it is intended to provide an active hydraulic booster system for a vehicle capable of securing sufficient braking force to a wheel within a relatively short time during sudden braking so as to shorten a braking distance in a sudden braking situation of a vehicle.

According to one aspect of the invention, the master cylinder; A reservoir coupled to the master cylinder to store brake fluid; A motor for driving a pump that pumps brake fluid from the reservoir; An inflow passage for guiding the pumped brake fluid to each wheel cylinder according to the operation of the pump driven by the motor; A backup passage connected to the inflow passage and guiding the brake fluid of the master cylinder to each of the wheel cylinders according to a foot force of a brake pedal; A cut valve provided in the backup passage to block the backup passage; And during sudden braking of the vehicle, a first hydraulic pressure is generated through the pump and supplied to each wheel cylinder through the inflow passage, and the cut valve is opened at the initial stage of the sudden braking to generate the first hydraulic pressure in the master cylinder by the pedal effort of the brake pedal. An active hydraulic booster system for a vehicle including; an electronic control unit that supplies the second hydraulic pressure to each wheel cylinder through the backup passage may be provided.

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In addition, the electronic control unit may include opening the cut valve for a preset time at the initial stage of the sudden braking and closing the cut valve when the preset time elapses.

In addition, the cut valve may include a normally open solenoid valve that maintains an open state.

In addition, the electronic control unit may include determining whether the vehicle is suddenly braking based on a pedal stroke of the brake pedal detected through a pedal stroke sensor that detects a pedal stroke of the brake pedal.

According to another aspect of the present invention, a master cylinder, a reservoir coupled to the master cylinder to store brake fluid, a motor driving a pump that pumps brake fluid from the reservoir, and the pump driven by the motor. Active of a vehicle including an inflow passage for guiding the brake fluid to each wheel cylinder according to operation, and a backup passage connected to the inflow passage and guiding the brake fluid of the master cylinder to the respective wheel cylinders according to the foot pressure of the brake pedal A hydraulic booster system, comprising: a cut valve provided in the backup passage to block the backup passage; A pedal stroke sensor for detecting a pedal stroke of the brake pedal; And determining whether the vehicle is suddenly braked based on the pedal stroke of the brake pedal detected through the pedal stroke sensor, and when the vehicle is suddenly braked, a first hydraulic pressure is generated through the pump to each wheel cylinder through the inflow passage. And an electronic control unit supplying the second hydraulic pressure generated to the master cylinder by the pedal effort of the brake pedal to each wheel cylinder through the backup passage by opening the cut valve at the initial stage of the sudden braking. An active hydraulic booster system of can be provided.

In addition, the electronic control unit may include opening the cut valve for a preset time at the beginning of the sudden braking and closing the cut valve when the preset time elapses.

According to an aspect of the present invention, it is possible to secure sufficient braking force to the wheel in a short time so that hydraulic pressure using the driver's brake pedal effort can be additionally used in addition to hydraulic pressure using an electric motor and a pump during sudden braking of a vehicle. You can shorten the distance.

1 is a hydraulic circuit diagram of an active hydraulic booster system for a vehicle according to an embodiment of the present invention.
2 is a schematic control block diagram of an active hydraulic booster system for a vehicle according to an embodiment of the present invention.
3 is a hydraulic circuit diagram for explaining a hydraulic flow when an AHB is operated in an active hydraulic booster system of a vehicle according to an embodiment of the present invention.
4 is a hydraulic circuit diagram for explaining hydraulic flow during emergency braking in an active hydraulic booster system for a vehicle according to an embodiment of the present invention.
5 is a hydraulic circuit diagram for explaining a hydraulic flow in a sudden braking situation in an active hydraulic booster system for a vehicle according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples in order to sufficiently convey the idea of the present invention to those of ordinary skill in the art. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly describe the present invention, parts irrelevant to the description are omitted from the drawings, and in the drawings, the width, length, thickness, etc. of the components may be exaggerated and expressed for convenience. The same reference numbers throughout the specification denote the same elements.

1 is a hydraulic circuit diagram of an active hydraulic booster system for a vehicle according to an embodiment of the present invention.

Referring to FIG. 1, an active hydraulic booster system of a vehicle can be largely divided into a hydraulic control device 100 and a power source unit 200.

The hydraulic control device 100 includes a master cylinder 110 through which force is transmitted from the brake pedal 30 ㄹ operated by the driver during braking, and a reservoir 115 that is coupled to an upper portion of the master cylinder 110 to store oil. ), and two hydraulic circuits (HC1, HC2) connected to two wheels (RR, RL, FR, FL), respectively, an accumulator 120 storing a certain level of pressure, and a master cylinder 110. A pedal simulator 180 provided to provide reaction force of the brake pedal 30 and a simulation valve 186 installed in a flow path connecting the pedal simulator 180 and the reservoir 115 are included.

In addition, the hydraulic control device 100 has two hydraulic circuits (HC1, HC2) and each of the accumulator 120 to control the pressure transmitted to the wheel cylinder 20 installed in each wheel (FL, FR, RL, RR). It may be configured to further include connected application valves 141 and 142 and release valves 143 and 144.

The power source unit 200 includes a pump 210 that sucks oil from the reservoir 115 and discharges it to the accumulator 120 to form pressure in the accumulator 120, and a motor 220 for driving the pump 210. ).

The hydraulic control device 100 and the power source unit 200 are connected to each other by an external pipe 10. That is, the pump 210 of the power source unit 200 and the accumulator 120 of the hydraulic control device 100 are connected by the external pipe 10.

Hereinafter, the structure and function of each component constituting the active hydraulic booster system of the vehicle will be described in more detail.

First, the master cylinder 110 has a first piston 111 and a second piston 112 formed therein so as to have two hydraulic circuits, and is configured to generate hydraulic pressure by the foot force of the brake pedal 30. The master cylinder 110 is connected to two hydraulic circuits HC1 and HC2, respectively. The reason that the master cylinder 110 has two hydraulic circuits is to ensure safety in case of failure. For example, of the two hydraulic circuits of the master cylinder 110, the first circuit may be connected to the right front wheel FR and the left rear wheel RL, and the other circuit may be connected to the left front wheel FL and the right rear wheel RR. have.

In the master cylinder 110, a reservoir 115 storing oil is installed in the upper side, and the oil leaked through the outlet is installed at the lower side to the wheel cylinder 20 installed in each wheel (RR, RL, FR, FL). Let it flow in.

On the other hand, reference numeral 31, which is not described, is an input rod installed on the brake pedal 30 for transmitting foot pressure to the master cylinder 110.

At least one pump 210 is provided to form a braking pressure by pumping oil flowing from the reservoir 115 at a high pressure, and a motor for providing a driving force to the pump 210 at one side of the pump 210 ( 220) is provided.

The accumulator 120 is provided at the outlet side of the pump 210 and temporarily stores high-pressure oil generated by driving the pump 210. That is, the accumulator 120 is connected to the pump 210 by an external pipe 10. At this time, a check valve 135 is installed in the external pipe 10 to prevent the high-pressure oil stored in the accumulator 120 from flowing back.

The connection passage 130 is connected to the external pipe 10 to transfer the braking oil stored in the accumulator 120 to the wheel cylinder 20. The connection passage 130 includes a first inlet passage BC1 and 131 connected to the first hydraulic circuit HC1 and a second inlet passage BC2 and 132 connected to the second hydraulic circuit HC2. The first hydraulic circuit HC1 is connected to the right front wheel FR and the left rear wheel RL of the vehicle, and the second hydraulic circuit HC2 is connected to the left front wheel FL and the right rear wheel RR.

A first application valve 141 and a first release valve 143 for controlling the braking oil stored in the accumulator 120 are provided in the first inflow passage BC1 and 131. A second application valve 142 and a second release valve 144 for controlling the braking oil stored in the accumulator 120 are provided in the second inlet passage BC2 132. Accordingly, the braking oil of the accumulator 120 may be delivered to each wheel cylinder 20 along the first inflow passage 131 and the second inflow passage 132.

The first and second application valves 141 and 142 and the first and second release valves 143 and 144 may be configured as normally closed solenoid valves that are maintained in a normally closed state. Accordingly, when the AHB is operated, the first and second application valves 141 and 142 are opened to transfer the braking oil stored in the accumulator 120 to the wheel cylinder 20.

A first inlet valve 151 is provided between the wheel cylinder 20 connected to the first inlet passage (BC1) 131, and a first inlet valve 151 is provided between the wheel cylinder 20 connected to the second inlet passage (BC2) 132. 2 Inlet valve 152 is provided.

The first inlet valve 151 may be formed of a normally open solenoid valve that is maintained in an open state. The first inlet valve 151 adjusts the amount of braking oil supplied from the accumulator 210 to the wheel cylinder 20 as the first application valve 141 is opened. The second inlet valve 152 may be configured to perform the same operation as the first inlet valve 151.

In addition, the hydraulic control device 100 may be configured to include a return passage 160 connecting the wheel cylinder 20 and the master cylinder 110. The return passage 160 is provided with a first outlet valve 161 and a second outlet valve 162 for outflowing the oil from the wheel cylinder 20 to the reservoir 115. The first outlet valve 161 and the second outlet valve 162 may be formed of a normally closed solenoid valve that is maintained in a normally closed state.

In addition, the hydraulic control device 100 further includes a pulsation damping device 145 provided in each of the first inlet passage (BC1) 131 and the second inlet passage (BC2) 132 to minimize pressure pulsation. Can be. The pulsation damping device 145 is a device capable of temporarily storing oil to attenuate the pulsation generated between the application valves 141 and 142 and the release valves 143 and 144 and the inlet valve 151, respectively.

The first backup passage 171 and the second backup passage 172 are master cylinders to enable emergency braking providing braking pressure to each wheel cylinder 20 by the operation of the brake pedal 30 when the AHB system fails. A flow path is formed between 110 and the wheel cylinder 20.

In the middle of the first backup passage 171, a first cut valve 173 for opening and closing the first backup passage 171 is provided. A second cut valve 174 for opening and closing the second backup passage 172 is provided in the middle of the second backup passage 172.

The first backup passage 171 is connected to the first inlet passage (BC1) 131 through the first cut valve 173, and the second backup passage 172 is connected to the second through the second cut valve 174. It is connected to the inflow passage (BC2) 132. The first backup passage 171 and the second backup passage 172 are blocked by the first cut valve 173 and the second cut valve 174 during AHB operation.

The first cut valve 173 and the second cut valve 174 may be formed of a normally open solenoid valve that maintains an normally open state.

One side of the master cylinder 110 is provided with a pedal simulator 180 for forming a foot pressure of the brake pedal 30.

The pedal simulator 180 includes a simulation chamber 182 provided to store oil flowing out from the outlet side of the master cylinder 110 and a simulation valve 186 provided on the inlet side of the simulation chamber 182. The simulation chamber 182 includes a piston 183 and an elastic member 184 and is formed to have a certain range of displacement by oil flowing into the simulation chamber 182. The simulator valve 186 is composed of a normally closed type solenoid valve that is maintained in a normally closed state, and is opened when the driver presses the brake pedal 30 to deliver the braking oil to the simulation chamber 182.

In addition, a simulation check valve 185 is provided between the pedal simulator 180 and the master cylinder 110, that is, between the pedal simulator 180 and the simulation valve 186, and the simulation check valve 185 is a master cylinder. It is connected with (110). The simulation check valve 185 is made so that the pressure according to the pedal effort of the brake pedal 30 is transmitted to the pedal simulator 180 only through the simulation valve 186. The simulation check valve 185 may be configured as a check valve for piping without a spring so that the residual pressure of the pedal simulator 180 is restored when the pedal effort of the brake pedal 30 is released.

Meanwhile, a pedal stroke sensor 105 for detecting a pedal stroke of the brake pedal 30 is provided on the side of the brake pedal 30. The pedal stroke sensor 105 detects a pedal stroke of the brake pedal 30 that changes when the driver depresses the brake pedal 30.

2 is a schematic control block diagram of an active hydraulic booster system for a vehicle according to an embodiment of the present invention.

Referring to FIG. 2, the active hydraulic booster system of the vehicle includes an electronic control unit 106 that performs overall control.

The pedal stroke sensor 105 is electrically connected to the input side of the electronic control unit 106.

On the output side of the electronic control unit 106, the first and second applied valves 141 and 142, the first and second release valves 143 and 144, the first and second cut valves 173 and 174, a simulation valve 186 and a motor 220 is electrically connected.

The electronic control unit 106 controls the pump 220 by using the motor 220 to provide braking force to the wheel based on the pedal stroke information of the brake pedal 30 detected through the pedal stroke sensor 105. It operates to directly generate hydraulic pressure and performs AHB control that controls the braking force of each wheel through the hydraulic pressure.

Meanwhile, the electronic control unit 106 provides braking power to each wheel through AHB operation using the motor 220 and the pump 220 in a sudden braking situation, and additionally to each wheel using hydraulic pressure according to the driver's brake pedal effort. Provides braking power. Accordingly, since two braking forces are provided to each wheel together, sufficient braking force can be secured in a short time, and thus braking response time and braking distance can be shortened.

Hereinafter, the operation of the electronic control unit 106 will be described in more detail.

3 is a hydraulic circuit diagram for explaining a hydraulic flow during AHB operation of an active hydraulic booster system of a vehicle according to an embodiment of the present invention.

Referring to FIG. 3, the electronic control unit 106 detects the pedal stroke of the brake pedal 30 through the pedal stroke sensor 105 when the driver depresses the brake pedal 30, and detects the detected pedal stroke of the brake pedal 30. A target pressure is determined according to the pedal stroke, and the high pressure braking oil is filled in the accumulator 120 by operating the pump 210 through the motor 220 to generate the determined target pressure. In this case, the target pressure may be a braking amount obtained by subtracting a regenerative braking amount from a required braking amount of the driver corresponding to the pedal stroke of the brake pedal 30.

The electronic control unit 106 opens the first and second application valves 141 and 142 so that the high-pressure braking oil filled in the accumulator 120 can be supplied to each wheel cylinder 20.

In addition to opening the applied valves 141 and 142, the electronic control unit 106 closes the first and second cut valves 173 and 174 provided in the first and second backup passages 171 and 172 to close the first and second backup passages. Blocks (171,172). Accordingly, the braking oil supplied to each wheel cylinder 20 through the first and second applied valves 141 and 142 does not flow back into the first and second backup passages 171 and 172. For this reason, the flow path between the master cylinder 110 and the first and second cut valves 173 and 174 constitutes a closed circuit.

Hydraulic flow in the direction indicated by the arrow is generated according to the series of operations of the above components.

4 is a hydraulic circuit diagram for explaining hydraulic flow during emergency braking of an active hydraulic booster system of a vehicle according to an embodiment of the present invention.

4, when emergency braking control is required, the electronic control unit 106 converts the first and second cut valves 173 and 174 installed in the first and second backup passages 171 and 172 to the original open state. , To convert the first and second application valves 141 and 142 to the original closed state. Accordingly, like the hydraulic flow in the direction of the arrow, the pressure of the master cylinder 110 due to the operation of the brake pedal 30 will be directly transferred to each wheel cylinder 20 through the first and second backup flow paths 171 and 172. I can. Accordingly, the vehicle can be braked by the pedal effort of the brake pedal 30.

5 is a hydraulic circuit diagram for explaining a hydraulic flow in a sudden braking situation in an active hydraulic booster system of a vehicle according to an embodiment of the present invention.

Referring to FIG. 5, the electronic control unit 106 drives the pump 210 through the motor 220 during sudden braking of the vehicle to generate the first hydraulic pressure supplied to each wheel cylinder 20 by being generated according to the pump operation. do. In addition, the electronic control unit 106 supplies the first hydraulic pressure generated by opening the first and second applied valves 141 and 142 to each of the wheel cylinders 20, and provides the first and second cut valves 173 and 174. The second hydraulic pressure generated in the master cylinder 111 is supplied to each wheel cylinder 20 according to the pedal effort of the brake pedal 30 by opening.

For example, when the driver presses the brake pedal 30, the electronic control unit 106 detects the pedal stroke of the brake pedal 30 through the pedal stroke sensor 105, and detects the pedal stroke of the brake pedal 30. According to the determination of the target pressure, the pump 210 is operated through the motor 220 to generate the determined target pressure, and the first and second application valves 141 and 142 are opened. Accordingly, the accumulator 120 is filled with high-pressure braking oil, and the high-pressure braking oil filled in the accumulator 120 is supplied to each wheel cylinder 20.

At this time, the electronic control unit 106 determines whether a sudden braking condition is performed using the pedal stroke of the brake pedal 30 detected through the pedal stroke sensor 105. For example, if the pedal stroke value of the brake pedal 30 is higher than the reference value set for the sudden braking determination and the time to reach the pedal stroke value reference value is shorter than the reference time set for the sudden braking determination, it is determined that it is a sudden braking situation. At this time, the sudden braking situation is also detected by using a sensor that detects another state of the vehicle (e.g., vehicle deceleration versus vehicle speed change, brake pedal displacement change, brake pedal angle change, etc.) instead of the pedal stroke sensor 105. It is possible.

The electronic control unit 106 is provided in the first and second backup passages 171 and 172 so that hydraulic pressure according to the pedal effort of the driver's brake pedal 30 can be provided to each wheel cylinder 20 at the beginning of the sudden braking situation. The first and second cut valves 173 and 174 are opened for a preset time at the beginning of the sudden braking. Accordingly, braking oil according to the foot pressure of the brake pedal 30 is additionally supplied to each wheel cylinder 20 through the first and second cut valves 173 and 174.

When a preset time elapses, the first and second cut valves 173 and 174 are closed to block the first and second backup flow paths 171 and 172. Accordingly, even if the pedal effort of the brake pedal 30 is weakened, the braking oil supplied to each wheel cylinder 20 through the first and second application valves 141 and 142 is passed through the first and second backup passages 171 and 172 It will not flow back to.

In this way, in a sudden braking situation, braking power is provided to each wheel through the AHB operation using the motor 220 and the pump 220, and additional braking force is provided to each wheel by using hydraulic pressure according to the brake pedal effort of the driver. Since two braking forces are provided together, sufficient braking force can be secured in a short time, thereby shortening the braking response time and braking distance.

105: pedal stroke sensor 106: electronic control unit
110: master cylinder 120: accumulator
130: connecting passage 131: first inflow passage
132: second inflow passage 135: check valve
141: first applied valve 142: second applied valve
160: return flow 171: first backup flow
172: second backup passage 173: first cut valve
174: second cut valve 180: pedal simulator
185: simulation check valve 186: simulation valve
200: power source unit 210: pump
220: motor

Claims (7)

Master cylinder;
A reservoir coupled to the master cylinder to store brake fluid;
A motor that drives a pump that pumps brake fluid from the reservoir;
An inflow passage for guiding the pumped brake fluid to each wheel cylinder according to the operation of the pump driven by the motor;
A backup passage connected to the inflow passage and guiding the brake fluid of the master cylinder to each of the wheel cylinders according to a foot force of a brake pedal;
A cut valve provided in the backup passage to block the backup passage; And
During sudden braking of the vehicle, the first hydraulic pressure is generated through the pump and supplied to each wheel cylinder through the inflow passage, and the cut valve is opened at the initial stage of the sudden braking, and generated in the master cylinder by the pedal effort of the brake pedal. An active hydraulic booster system for a vehicle including; an electronic control unit supplying a second hydraulic pressure to each wheel cylinder through the backup passage. delete The method of claim 1,
The electronic control unit opens the cut valve for a preset time at the initial stage of the sudden braking, and closes the cut valve when the preset time elapses. The method of claim 1,
The cut valve is an active hydraulic booster system for a vehicle that is a normally open solenoid valve that maintains an open state. The method of claim 1,
The electronic control unit is an active hydraulic booster system for a vehicle that determines whether the vehicle is suddenly braked based on a pedal stroke of the brake pedal detected through a pedal stroke sensor that detects a pedal stroke of the brake pedal. A master cylinder, a reservoir coupled to the master cylinder to store brake fluid, a motor that drives a pump that pumps brake fluid from the reservoir, and brake fluid from each wheel according to the operation of the pump driven by the motor. In the active hydraulic booster system of a vehicle comprising an inlet passage for guiding a cylinder, and a backup passage connected to the inlet passage and guiding the brake fluid of the master cylinder to each of the wheel cylinders according to a foot force of a brake pedal,
A cut valve provided in the backup passage to block the backup passage;
A pedal stroke sensor for detecting a pedal stroke of the brake pedal; And
Based on the pedal stroke of the brake pedal detected through the pedal stroke sensor, it is determined whether the vehicle is suddenly braked, and when the vehicle is suddenly braked, a first hydraulic pressure is generated through the pump to each wheel cylinder through the inflow passage. And an electronic control unit that opens the cut valve at the initial stage of the sudden braking while supplying the second hydraulic pressure generated in the master cylinder by the pedal effort of the brake pedal to each wheel cylinder through the backup passage. Active hydraulic booster system. The method of claim 6,
The electronic control unit is an active hydraulic booster system for a vehicle that opens the cut valve for a preset time at the beginning of the sudden braking and closes the cut valve when the preset time elapses.

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