An electro-hydraulic brake system and fail-degraded control method

Abstract

The application discloses an electronic hydraulic brake system and a failure degradation control method, and belongs to the technical field of vehicle control. The electronic hydraulic brake system comprises a master control unit, a backup unit and a plurality of wheel speed sensors. The master control unit realizes comprehensive dynamic control of a vehicle, and comprises a first control valve, a brake master cylinder assembly and a first controller connected with the first control valve. At least a part of the brake master cylinder assembly is arranged in the first control valve. The backup unit is used for providing basic braking when the master control unit fails, and comprises a second control valve and a second controller connected with the second control valve. The wheel speed sensors are arranged on the wheels and are electrically connected with the first and second controllers. Hydraulic circuit break valves are arranged on hydraulic circuits between the master control unit and the wheel brakes, between the backup unit and the wheel brakes and between the master control unit and the backup unit, and are used for turning on and turning off the corresponding hydraulic circuits. The application solves the problems of complex structure, large weight and high quality requirement of a hydraulic brake system of a new energy vehicle in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle technology, specifically relating to an electro-hydraulic braking system and a failure degradation control method. Background Technology

[0002] The automotive braking system is part of the vehicle chassis system. This system typically consists of components such as the brake pedal, vacuum booster, master cylinder, electronic stability control system, brakes, and connecting lines. The entire braking system works as follows: when the driver presses the brake pedal, the system is activated. The vacuum booster, relying on the vacuum source generated by the engine, provides assistance and amplifies the braking force, which is ultimately transmitted hydraulically to the brakes, causing the vehicle to decelerate or stop. This braking system is widely used in traditional gasoline-powered vehicles.

[0003] However, when applying traditional braking systems to new energy vehicles, since there is no engine to provide a vacuum source, an additional electronic vacuum pump must be added to power the vacuum booster. At the same time, traditional braking systems already suffer from numerous components, require a large number of mounting brackets, and suffer from structural complexity and weight due to mechanical, hydraulic, and electrical connections. Adding an electronic vacuum pump not only fails to simplify the original structure but also increases additional weight, energy consumption, and potential failure points, exacerbating systemic defects. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides an electro-hydraulic braking system and a failure degradation control method.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, an electro-hydraulic braking system is provided, comprising:

[0007] The main control unit for realizing integrated dynamic control of the vehicle includes a first control valve, a brake master cylinder assembly, and a first controller. The first control valve has multiple fluid outlets, and the fluid outlets of the first control valve are connected to the fluid inlets of the wheel brakes and the backup unit. At least a portion of the brake master cylinder assembly is disposed within the first control valve, and the end of the brake master cylinder assembly is connected to the brake pedal. The first controller is connected to the first control valve.

[0008] A backup unit for providing basic braking in the event of failure of the main control unit includes a second control valve and a second controller. The second control valve has multiple inlet and outlet ports, and the outlet port of the second control valve is connected to the inlet port of the wheel brake. The second controller is connected to the second control valve.

[0009] Multiple wheel speed sensors are installed at each wheel and electrically connected to the first controller and the second controller, for real-time acquisition of wheel speed signals, and the signals are provided to the first controller and the second controller respectively for braking control calculations;

[0010] Hydraulic circuit on / off valves are provided in the hydraulic circuits between the main control unit and the wheel brake, between the main control unit and the backup unit, and between the backup unit and the wheel brake. The hydraulic circuit on / off valves include normally open solenoid valves and normally closed solenoid valves, which are used to control the on / off of the corresponding hydraulic circuits.

[0011] In some embodiments, the first control valve includes:

[0012] First valve body;

[0013] A first solenoid valve is disposed between the first valve body and the first controller, and its opening and closing are controlled by the coil of the first controller; and

[0014] A first motor is mounted on the first valve body. The first motor is controlled by a drive signal output by the first controller. A second pressure sensor is provided on the hydraulic circuit associated with the first motor to monitor whether the pressure build-up output of the first motor is normal.

[0015] In some embodiments, the brake master cylinder assembly includes:

[0016] A master cylinder assembly, housed within the first valve body, is hydraulically connected to both the wheel brakes. The master cylinder assembly is equipped with a first pressure sensor to monitor its pressure build-up state, and a pedal position sensor to acquire brake pedal displacement signals.

[0017] A pedal simulator is connected to the master cylinder assembly via a hydraulic circuit. The pedal simulator is equipped with a spring for providing a reverse thrust to the master cylinder assembly and simulating the braking feel.

[0018] In some embodiments, a normally closed solenoid valve is provided on the hydraulic circuit formed between the master cylinder assembly and the pedal simulator. The normally closed solenoid valve cuts off the hydraulic circuit between the master cylinder assembly and the pedal simulator when the main control unit loses power. A normally open solenoid valve is provided on the hydraulic circuit between the master cylinder assembly and the wheel brake. The normally open solenoid valve connects the hydraulic circuit between the master cylinder assembly and the wheel brake when the main control unit loses power.

[0019] In some embodiments, the second control valve includes:

[0020] Second valve body;

[0021] A second solenoid valve is disposed between the second valve body and the second controller, and its opening and closing are controlled by the coil of the second controller; and

[0022] The second motor is mounted on the second valve body. The second motor is controlled by the drive signal output by the second controller. A third pressure sensor for monitoring the hydraulic pressure of the master cylinder assembly is provided on the hydraulic circuit associated with the second motor.

[0023] In some embodiments, a plurality of normally closed solenoid valves are provided in the hydraulic passage inside the backup unit, and the opening or closing operation of the normally closed solenoid valves is controlled by the coil of the second controller.

[0024] Secondly, a failure degradation control method is provided, applicable to the aforementioned electro-hydraulic braking system, comprising the following steps:

[0025] When the electro-hydraulic braking system is in the first failure mode, the signal collected by the first controller from the second pressure sensor is inconsistent with the signal collected by the rotor position sensor of the first motor. At this time, the first controller outputs a fault alarm signal to the vehicle controller. At the same time, the first controller drives the first motor to increase the rotation angle and makes the second pressure sensor reach the set value. The main control unit is in the braking operation state, and the backup unit ensures the continuity of the brake line.

[0026] When the electro-hydraulic braking system is in the second failure mode, the first controller does not receive a valid pressure signal from the second pressure sensor. At this time, the first controller sends a fault alarm signal to the vehicle controller and the second controller. After that, the main control unit stops working, and the backup unit starts the second motor through the voltage signal of the third pressure sensor. The backup unit opens the normally closed solenoid valve inside the backup unit and closes the normally open solenoid valve inside the backup unit. It also draws brake fluid from the master cylinder assembly, pressurizes it, and transmits it to the front wheels of the vehicle. The brake fluid output by the master cylinder assembly enters the rear wheels of the vehicle to jointly perform the vehicle braking work.

[0027] When the electro-hydraulic braking system is in the third failure mode, the first controller cannot calculate the speed and rotational speed of the first motor based on the signal collected by the pedal position sensor. At this time, the first controller outputs a fault alarm signal to the vehicle controller. After that, the first controller controls the angle and rotational speed of the first motor based on the pressure value and change rate of the second pressure sensor and realizes vehicle braking through the main control unit.

[0028] When the electro-hydraulic braking system is in the fourth failure mode, the backup unit is in a completely de-energized state. At this time, the second controller sends a fault signal to the vehicle controller, and then the main control unit performs the vehicle braking operation.

[0029] When the electro-hydraulic braking system is in the fifth failure mode, both the main control unit and the backup unit are completely de-energized. The driver pushes the master cylinder assembly forward by pressing the brake pedal, causing brake fluid to enter the wheel brakes and achieve vehicle braking.

[0030] The beneficial effects of this invention are as follows: The master cylinder, power assist mechanism, and electronic stability control (ESC) system are integrated into the main control unit, achieving integrated braking control and significantly simplifying the coordination between the hydraulic circuit and electrical system of the braking system. The backup unit, as an independent redundant module, is connected in series with the main control unit, retaining only the active boost function. It initiates takeover braking when the main control unit fails, reducing the service life requirements of the backup unit and enhancing the safety of the braking system. Furthermore, the main control unit and backup unit form a dual-level safety guarantee. Wheel speed sensors collect the rotational speeds of all four wheels in real time and transmit data synchronously, supporting independent calculation and control. This effectively solves the problems of complex structure, large weight, and high quality requirements in the hydraulic braking system of new energy vehicles. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a hydraulic schematic diagram of an electro-hydraulic braking system provided in one embodiment of the present invention;

[0033] Figure 2 This is a hardware connection diagram of an electro-hydraulic braking system provided in one embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the main control unit provided in one embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the backup unit provided in one embodiment of the present invention. Detailed Implementation

[0036] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] This invention provides an electro-hydraulic braking system that solves the problems of complex structure, large weight, and high quality requirements in hydraulic braking systems for new energy vehicles. This invention also provides a failure degradation control method applying this electro-hydraulic braking system.

[0038] like Figure 1-4 As shown, in one embodiment, the electro-hydraulic braking system 10 includes a main control unit 20, a backup unit 30, and multiple wheel speed sensors 40. Hydraulic circuit on / off valves are provided in the hydraulic circuits between the main control unit 20 and the wheel brakes, between the main control unit 20 and the backup unit 30, and between the backup unit 30 and the wheel brakes. These valves include normally open solenoid valves and normally closed solenoid valves, used to control the on / off state of the corresponding hydraulic circuits.

[0039] The main control unit 20 is used to realize the dynamic comprehensive control of the vehicle, including a first control valve 202, a brake master cylinder assembly 203 and a first controller 204. The first control valve 202 has multiple fluid outlet holes, which are connected to the fluid inlet holes of the wheel brakes and the backup unit 30. At least a portion of the brake master cylinder assembly 203 is disposed in the first control valve 202, and the end of the brake master cylinder assembly 203 is connected to the brake pedal. The first controller 204 is connected to the first control valve 202.

[0040] In one embodiment, such as Figure 3 As shown, the main control unit 20 includes an oil reservoir 201, a first control valve 202, a brake master cylinder assembly 203, and a first controller 204. The first control valve 202 includes a first valve body 2021, a first solenoid valve 2026, and a first motor 2022. The first solenoid valve 2026 is interference-fitted with the first valve body 2021 and located in the cavity formed by the first valve body 2021 and the first controller 204. The first motor 2022 is fixed to the front side of the first valve body 2021 by bolts. The shaft of the first motor 2022 is clearance-fitted with the plunger 2023. The rotor position sensor 2024 passes through the plunger 2023 and is interference-fitted with the limiting hole on the first motor 2022. The first motor 2022 is controlled by the drive signal output by the first controller 204. A second pressure sensor 2025 is provided on the hydraulic circuit associated with the first motor 2022 to monitor whether the pressure build-up output of the first motor 2022 is normal. At the same time, the first control valve 202 has multiple liquid outlet holes, which are connected to the liquid inlet holes of the wheel brake and the backup unit 30 through hydraulic pipes.

[0041] The first controller 204 includes a first control box 2041, a first coil 2042, and a first PCBA board 2043. The first control box 2041 is fixed to the rear side of the first valve body 2021 by bolts. The first coil 2042 is connected to the first PCBA board 2043 by soldering and installed inside the first control box 2041. The first coil 2042 is fitted with a first solenoid valve 2026. The first PCBA board 2043 directly controls the opening and closing of the valve core inside the first solenoid valve 2026 by controlling the first coil 2042 to generate or close the electromagnetic field.

[0042] The brake master cylinder assembly 203 includes a master cylinder assembly 2031 and a pedal simulator 2032. The master cylinder assembly 2031 is mounted on a first valve body 2021. The fluid outlet of the master cylinder assembly 2031 is connected to the fluid inlet of the wheel brake via a hydraulic pipe. At least a portion of the master cylinder assembly 2031 is located within the first valve body 2021. A brake pedal is connected to the end of the master cylinder assembly 2031. A first pressure sensor 2034 is mounted on the master cylinder assembly 2031 to monitor the pressure build-up status of the master cylinder assembly 2031. A pedal position sensor 2033 is mounted on the master cylinder assembly 2031 to collect brake pedal displacement signals. The pedal position sensor 2033 is connected to the first valve body 2021 by valve body riveting deformation. The pedal simulator 2032 is connected to the master cylinder assembly 2031 via a hydraulic circuit. The pedal simulator 2032 has a spring for providing reverse thrust to the master cylinder assembly 2031 and simulating the brake pedal feel. In addition, a normally closed solenoid valve is installed on the hydraulic circuit formed between the master cylinder assembly 2031 and the pedal simulator 2032. When the main control unit 20 loses power, the normally closed solenoid valve cuts off the hydraulic circuit between the master cylinder assembly 2031 and the pedal simulator 2032. A normally open solenoid valve is installed on the hydraulic circuit between the master cylinder assembly 2031 and the wheel brake. When the main control unit 20 loses power, the normally open solenoid valve connects the hydraulic circuit between the master cylinder assembly 2031 and the wheel brake.

[0043] Oil reservoir 201 is positioned above the first valve body 2021 and fixed by bolts. Oil reservoir 201 and wheel brake are both connected through hydraulic pipes. In one embodiment, as shown in the figure, a normally open solenoid valve is provided between the oil reservoir 201 and the hydraulic circuit of the vehicle brake. When the main control unit 20 is not working, the normally open solenoid valve connects the hydraulic circuit between the oil reservoir 201 and the vehicle brake.

[0044] In one embodiment, such as Figure 4As shown, the backup unit 30 provides basic braking in the event of a failure of the main control unit 20, and includes a second control valve 301 and a second controller 302. The second control valve 301 has multiple inlet and outlet ports, with the outlet port communicating with the inlet port of the wheel brake. The second control valve 301 includes a second valve body 3011, a second solenoid valve 3012, and a second motor 3013. The second solenoid valve 3012 is interference-fitted with the second valve body 3011 and connected by riveting deformation. The second motor 3013 is bolted to the front of the second valve body 3011 and controlled by a drive signal output from the second controller 302. A third pressure sensor 3014 is installed on the hydraulic circuit associated with the second motor 3013 to monitor the master brake cylinder. The component build-up pressure; the second controller 302 is signal-connected to the first controller 204 and includes a second control box 3022, a second coil 3021, and a second PCBA board 3023. The second control box 3022 is fixed to the rear side of the second valve body 3011 by bolts. The second coil 3021 and the second PCBA board 3023 are connected by soldering and installed together in the second control box 3022. The second coil 3021 houses a second solenoid valve 3012. The second PCBA board 3023 directly controls the opening and closing of the valve core inside the second solenoid valve 3012 by controlling the generation or deactivation of the electromagnetic field by the second coil 3021. In one embodiment, the backup unit 30 has a first pump body 3031 and a second pump body 3032. Both the first pump body 3031 and the second pump body 3032 are used to pressurize the brake fluid drawn from the master cylinder assembly 2031. Both the first pump body 3031 and the second pump body 3032 are one-way valves with an opening hydraulic pressure of 0.05 MPa. In one embodiment, a plurality of normally closed solenoid valves are provided in the hydraulic passage inside the backup unit 30. The through-hole diameter of the normally closed solenoid valve is 3.5 mm, and the opening or closing operation of the normally open solenoid valve is controlled by the second coil 3021.

[0045] In one embodiment, such as Figure 2 As shown, multiple wheel speed sensors 40 are installed at each wheel and are electrically connected to the first controller 204 and the second controller 302, respectively, to collect wheel speed signals in real time and provide the signals to the first controller 204 and the second controller 302 for braking control calculations.

[0046] In one embodiment, the electro-hydraulic braking system 10 is applied to an automotive braking system and has multiple functions such as conventional braking and vehicle anti-lock braking, as detailed below:

[0047] 1. Conventional braking function

[0048] When the driver depresses the brake pedal, the master cylinder assembly 2031 advances to discharge brake fluid. Simultaneously, the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076 close, and the seventh normally closed solenoid valve 2067 opens, allowing the brake fluid discharged from the master cylinder to flow into the pedal simulator 2032. At the same time, the first controller 204 acquires the pedal position signal and, after control calculation, drives the first motor 2022 to rotate and push the plunger 2023 forward, opening the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066. At this time, the brake fluid pushed out by the plunger 2023 flows through the fifth normally closed solenoid valve 2065. After passing through the sixth normally closed solenoid valve 2066, the flow splits into two paths: one path flows through the first normally open solenoid valve 2071 and the fourth normally open solenoid valve 2074, enters the backup unit 30 through the first inlet port P1 and the second inlet port P2, and then flows out through the eighth normally open solenoid valve 3078 and the ninth normally open solenoid valve 3079 in the backup unit 30, exits through the first outlet port S1 and the second outlet port S2, and enters the front wheel brake of the vehicle to achieve pressure braking of the front wheels; the other path flows through the second normally open solenoid valve 2072 and the third normally open solenoid valve 2073 to enter the rear wheel brake of the vehicle to achieve pressure braking of the rear wheels, thereby achieving pressure braking of both the front and rear wheels.

[0049] 2. Vehicle anti-lock braking system

[0050] When the vehicle brakes suddenly, the driver quickly presses the brake pedal, triggering the normal braking process: the master cylinder assembly 2031 advances to discharge brake fluid, which flows into the pedal simulator 2032, closing the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076, and opening the seventh normally closed solenoid valve 2067. Then, the first controller 204 acquires the pedal position signal and performs control calculations, driving the first motor 2022 to push the plunger 2023 forward. Simultaneously, the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066 open, and the brake fluid pushed out by the plunger 2023 flows through the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066. After the sixth normally closed solenoid valve 2066, the flow splits into two paths: one path flows through the first normally open solenoid valve 2071 and the fourth normally open solenoid valve 2074, enters the backup unit 30 through the first inlet port P1 and the second inlet port P2, and then flows out through the eighth normally open solenoid valve 3078 and the ninth normally open solenoid valve 3079 in the backup unit 30, exits through the first outlet port S1 and the second outlet port S2, and enters the front wheel brake of the vehicle to achieve pressure braking of the front wheels; the other path flows through the second normally open solenoid valve 2072 and the third normally open solenoid valve 2073 to enter the rear wheel brake of the vehicle to achieve pressure braking of the rear wheels, thereby achieving pressure braking of the front and rear wheels.

[0051] In addition, the wheel speed sensor 40 monitors the wheel speed in real time. If the main control unit 20 determines that the wheel is about to lock up, it opens the corresponding first normally closed solenoid valve 2061, second normally closed solenoid valve 2062, third normally closed solenoid valve 2063 and fourth normally closed solenoid valve 2064 to release brake fluid to reduce braking force and prevent wheel lockup.

[0052] 3. Vehicle Stability Control Function

[0053] When the vehicle turns (e.g., a left turn), the main control unit 20 detects the vehicle's attitude through the inertial unit and the steering wheel angle sensor. If understeering is detected, the first motor 2022 is driven to push the plunger 2023 to build pressure, closing the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076, opening the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066, and closing the first normally open solenoid valve 2071, the second normally open solenoid valve 2072, and the fourth normally open solenoid valve 2074. This allows the brake fluid to flow through the third normally open solenoid valve 2073 to apply pressure to the left rear wheel, reducing its speed to correct understeering. If an oversteer risk is detected, the same logic applies: piston 2023 builds pressure, closing the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076, opening the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066, closing the first normally open solenoid valve 2071, the third normally open solenoid valve 2073, and the fourth normally open solenoid valve 2074, and opening the second normally open solenoid valve 2072. This allows brake fluid to flow through the second normally open solenoid valve 2072 to apply pressure to the right rear wheel to stabilize the vehicle. (The right turn control logic is similar.)

[0054] 4. Traction control function

[0055] When the vehicle starts on a low-traction surface, if the main control unit 20 detects front wheel slippage through the wheel speed sensor 40, it executes dual control: 1) it requests the vehicle controller 50 to reduce the torque output of the vehicle drive motor via CAN communication; 2) it simultaneously drives the first motor 2022 to push the plunger 2023 to build pressure, closes the second normally open solenoid valve 2072, the fourth normally open solenoid valve 2074, the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076, and opens the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066, so that the brake fluid flows through the first normally open solenoid valve 2071 and the fourth normally open solenoid valve 2074 to enter the front wheel brakes to apply braking force, reduce the speed of the slipping wheel, and alleviate the vehicle slippage.

[0056] 5. Regenerative braking function

[0057] When the driver applies low-intensity braking and presses the brake pedal, the master cylinder assembly 2031 discharges brake fluid (at this time, the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076 are closed, and the seventh normally closed solenoid valve 2067 is open), and the brake fluid flows into the pedal simulator 2032; the main control unit 20 collects the pedal position signal, determines that it is low-intensity braking, and sends a vehicle deceleration request to the vehicle controller 50 through CAN communication; the vehicle controller 50 controls the drive motor of the vehicle to switch to generator mode, generates braking torque to drag and decelerate the vehicle, and stores the generated electrical energy in the vehicle's energy storage device, thereby realizing brake energy recovery.

[0058] 6. Active braking function

[0059] When the vehicle's radar or camera detects a collision risk, the vehicle controller 50 sends a deceleration request to the main control unit 20. The main control unit 20 then drives the first motor 2022 to push the plunger 2023 forward, closing the fifth normally open solenoid valve 2075 and the sixth normally open solenoid valve 2076, and opening the fifth normally closed solenoid valve 2065 and the sixth normally closed solenoid valve 2066. The brake fluid pushed out by the plunger 2023 flows through these valves and is divided into two paths: one path passes through the backup unit 30 (via the eighth normally open solenoid valve 3078 and the ninth normally open solenoid valve 3079) into the front wheel brakes; the other path directly enters the rear wheel brakes, thus achieving active braking of all wheels without driver intervention.

[0060] 7. Backup unit 30 braking function

[0061] When the main control unit 20 plunger 2023 mechanism or electrical system fails, the driver presses the brake pedal. The backup unit 30 confirms the failure signal of the main control unit 20 through the vehicle controller 50. The backup unit 30 controller collects the signal from the third pressure sensor 3014 to determine the depth of the driver's brake pedal press, drives the second motor 3013 to rotate, and drives the first pump body 3031 and the second pump body 3032 to work. At the same time, the eighth normally closed solenoid valve 3068 and the ninth normally closed solenoid valve 3069 are opened, and the eighth normally open solenoid valve 3078 and the ninth normally open solenoid valve 3079 are closed. The first pump body 3031 and the second pump body 3032 draw brake fluid from the master cylinder of the main air unit through the eighth normally closed solenoid valve 3068 and the ninth normally closed solenoid valve 3069, pressurize it and send it to the brakes of each wheel to realize vehicle braking.

[0062] In one embodiment, such as Figure 1 As shown, a failure degradation control method includes the following steps:

[0063] When the electro-hydraulic braking system 10 is in the first failure mode, the signal collected by the first controller 204 from the second pressure sensor 2025 is inconsistent with the signal collected by the rotor position sensor 2024 of the first motor 2022. At this time, the first controller 204 outputs a fault alarm signal to the vehicle controller 50. At the same time, the first controller 204 drives the first motor 2022 to increase the rotation angle and make the second pressure sensor 2025 reach the set value. The main control unit 20 is in the braking operation state, and the backup unit 30 ensures the connection of the brake line. In one embodiment, the first failure mode is a slight leakage failure of the electro-hydraulic braking system 10.

[0064] When the electro-hydraulic braking system 10 is in the second failure mode, the first controller 204 does not receive a valid pressure signal from the second pressure sensor 2025. At this time, the first controller 204 sends a fault alarm signal to the vehicle controller 50 and the second controller 302. After that, the main control unit 20 exits operation, and the backup unit 30 starts the second motor 3013 according to the pressure signal from the third pressure sensor 3014. The backup unit opens the normally closed solenoid valve and closes the normally open solenoid valve inside, and draws brake fluid from the master cylinder assembly 2031 and transmits it to the front wheels of the vehicle after pressurization. The brake fluid output from the master cylinder assembly 2031 enters the rear wheels of the vehicle to jointly perform vehicle braking. In one embodiment, the second failure mode is a failure of the plunger 2023 or an electrical failure in the main control unit 20.

[0065] When the electro-hydraulic braking system 10 is in the third failure mode, the first controller 204 cannot calculate the rotational speed and rotational speed of the first motor 2022 based on the signal collected by the pedal position sensor 2033. At this time, the first controller 204 outputs a fault alarm signal to the vehicle controller 50. Then, the first controller 204 controls the angle and rotational speed of the first motor 2022 based on the pressure value and change rate of the second pressure sensor 2025 and realizes vehicle braking through the main control unit 20. In one embodiment, the third failure mode is the failure of the pedal position signal of the main control unit 20.

[0066] When the electro-hydraulic braking system 10 is in the fourth failure mode, the backup unit 30 is completely de-energized. At this time, the second controller 302 sends a fault signal to the vehicle controller 50, and the main control unit 20 performs vehicle braking. In one embodiment, the fourth failure mode is the failure of the backup unit 30.

[0067] When the electro-hydraulic braking system 10 is in the fifth failure mode, both the main control unit 20 and the backup unit 30 are completely de-energized. The driver pushes the master cylinder assembly 2031 forward by pressing the brake pedal, causing brake fluid to enter the wheel brakes and achieve vehicle braking. In one embodiment, the fifth failure mode is a vehicle power failure.

[0068] The main control unit 20 of this invention integrates the master cylinder assembly 2031 and the first controller 204. While achieving braking function, it significantly reduces structural weight and floor space. The main control unit 20 uses the first motor 2022 to drive the plunger 2023 to quickly build up pressure without relying on a vacuum source. The isolation design between the master cylinder and the plunger 2023 of the main control unit 20 ensures that even if the main control unit 20 fails electrically, the driver can still push the master cylinder assembly 2031 through the brake pedal and output brake fluid to the wheel brakes. The pressure sensor in the main control unit 20 can monitor the unit status in real time and accurately identify failure conditions. The independently set backup unit 30 can actively draw brake fluid from the reservoir 201 and pressurize it to output to the wheel brakes during the failure of the main control unit 20. The independent pressure sensor in the backup unit 30 can collect pressure change data of the master cylinder assembly 2031 in real time during the electrical failure of the main control unit 20 and automatically adjust its own pressure and speed of pressure building. In addition, the electro-hydraulic braking system 10 of this invention can meet different braking needs of the vehicle, and the failure degradation control of the system is comprehensive.

[0069] The above description is merely a preferred embodiment of one or more embodiments of this specification and is not intended to limit the scope of one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the protection scope of one or more embodiments of this specification.

Claims

1. A failure degradation control method, characterized in that, The invention relates to an electro-hydraulic braking system, characterized in that the electro-hydraulic braking system includes a main control unit for realizing integrated dynamic control of the vehicle, a backup unit for providing basic braking in the event of failure of the main control unit, and multiple wheel speed sensors. The main control unit includes a first control valve, a brake master cylinder assembly, and a first controller. The first control valve has multiple liquid outlets, and the liquid outlets of the first control valve are connected to the liquid inlets of the wheel brakes and the backup unit. At least a portion of the brake master cylinder assembly is disposed within the first control valve, and the end of the brake master cylinder assembly is connected to the brake pedal. The first controller is connected to the first control valve. The backup unit includes a second control valve and a second controller. The second control valve has multiple inlet and outlet ports, and the outlet port of the second control valve is connected to the inlet port of the wheel brake. The second controller is connected to the second control valve. Multiple wheel speed sensors are installed at each wheel and are electrically connected to the first controller and the second controller to collect wheel speed signals in real time and provide the signals to the first controller and the second controller respectively for braking control calculations; Hydraulic circuit on / off valves are provided in the hydraulic circuits between the main control unit and the wheel brake, between the main control unit and the backup unit, and between the backup unit and the wheel brake. The hydraulic circuit on / off valves include normally open solenoid valves and normally closed solenoid valves, which are used to control the on / off of the corresponding hydraulic circuits. The failure degradation control method includes the following steps: When the electro-hydraulic braking system is in the first failure mode, the signal collected by the first controller from the second pressure sensor is inconsistent with the signal collected by the rotor position sensor of the first motor of the first control valve. At this time, the first controller outputs a fault alarm signal to the vehicle controller. At the same time, the first controller drives the first motor to increase the rotation angle and makes the second pressure sensor reach the set value. The main control unit is in the braking operation state, and the backup unit ensures the continuity of the brake line. When the electro-hydraulic braking system is in the second failure mode, the first controller does not receive a valid pressure signal from the second pressure sensor. At this time, the first controller sends a fault alarm signal to the vehicle controller and the second controller. After that, the main control unit stops working, and the backup unit starts the second motor of the second control valve through the pressure signal of the third pressure sensor of the second control valve. The backup unit opens the normally closed solenoid valve inside the backup unit and closes the normally open solenoid valve inside the backup unit. Brake fluid is drawn from the master cylinder assembly and transmitted to the front wheels of the vehicle after being pressurized. The brake fluid output by the master cylinder assembly enters the rear wheels of the vehicle to jointly perform the vehicle braking work. When the electro-hydraulic braking system is in the third failure mode, the first controller cannot calculate the speed and rotational speed of the first motor based on the signal collected by the pedal position sensor of the brake master cylinder assembly. At this time, the first controller outputs a fault alarm signal to the vehicle controller. After that, the first controller controls the angle and rotational speed of the first motor based on the pressure value and change rate of the second pressure sensor and realizes vehicle braking through the main control unit. When the electro-hydraulic braking system is in the fourth failure mode, the backup unit is in a completely de-energized state. At this time, the second controller sends a fault signal to the vehicle controller, and then the main control unit performs the vehicle braking operation. When the electro-hydraulic braking system is in the fifth failure mode, both the main control unit and the backup unit are completely de-energized. The driver pushes the master cylinder assembly forward by pressing the brake pedal, causing brake fluid to enter the wheel brakes and achieve vehicle braking.

2. The failure degradation control method according to claim 1, characterized in that, The first control valve includes: First valve body; A first solenoid valve is disposed between the first valve body and the first controller, and is controlled to open and close by a coil of the first controller; and A first motor is mounted on the first valve body. The first motor is controlled by a drive signal output by the first controller. A second pressure sensor is provided on the hydraulic circuit associated with the first motor to monitor whether the pressure build-up output of the first motor is normal.

3. The failure degradation control method according to claim 2, characterized in that, The brake master cylinder assembly includes: A master cylinder assembly, disposed within the first valve body, is hydraulically connected to both the wheel brakes. The master cylinder assembly is equipped with a first pressure sensor for monitoring the pressure build-up state of the master cylinder assembly, and a pedal position sensor for acquiring brake pedal displacement signals. A pedal simulator is connected to the master cylinder assembly via a hydraulic circuit. The pedal simulator is equipped with a spring for providing a reverse thrust to the master cylinder assembly and simulating the braking feel.

4. The failure degradation control method according to claim 3, characterized in that, A normally closed solenoid valve is installed on the hydraulic circuit formed between the master cylinder assembly and the pedal simulator. The normally closed solenoid valve cuts off the hydraulic circuit between the master cylinder assembly and the pedal simulator when the main control unit loses power. A normally open solenoid valve is installed on the hydraulic circuit between the master cylinder assembly and the wheel brake. The normally open solenoid valve connects the hydraulic circuit between the master cylinder assembly and the wheel brake when the main control unit loses power.

5. The failure degradation control method according to claim 1, characterized in that, The second control valve includes: Second valve body; A second solenoid valve is disposed between the second valve body and the second controller, and its opening and closing are controlled by the coil of the second controller; and The second motor is mounted on the second valve body. The second motor is controlled by a drive signal output by the second controller. A third pressure sensor for monitoring the hydraulic pressure of the master cylinder assembly is provided on the hydraulic circuit associated with the second motor.

6. The failure degradation control method according to claim 5, characterized in that, The backup unit has multiple normally closed solenoid valves installed in the hydraulic passage. The opening or closing of the normally closed solenoid valves is controlled by the coil of the second controller.

Images