Medium off-road vehicle electronic hydraulic braking system and control method

Abstract

This invention relates to an electronic hydraulic braking system and control method for a medium-sized off-road vehicle. The system includes a brake fluid reservoir connected to a master cylinder, a front axle power unit, and a rear axle power unit. The master cylinder is connected to a hydraulic power assist unit, and the front and rear axle power units are also connected to the hydraulic power assist unit. The hydraulic power assist unit is connected to the wheel brake cylinders via a hydraulic ESC regulator. The master cylinder forms an independent dual-channel circuit, enabling independent control of the front and rear axle braking circuits. The hydraulic power assist unit and the hydraulic ESC regulator form independent front and rear dual-circuit hydraulic control units, which can independently control the oil pressure of the front and rear axle brake cylinders. This effectively achieves adjustable braking force at each wheel, helping the driver control the vehicle to achieve a safe driving speed and improving braking safety.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking control technology, and in particular to an electro-hydraulic braking system and control method for a medium-sized off-road vehicle. Background Technology

[0002] Electro-hydraulic braking system (EHB) is a type of brake-by-wire system. During braking, it can accurately calculate the pedal displacement and pedal force for each braking action and convert them into electrical signals that are transmitted to the hydraulic control unit. The hydraulic control unit automatically adjusts the braking force of each wheel according to different operating conditions to achieve reliable braking of the vehicle. Due to its many advantages such as compact structure, low noise, and good pedal feel, it is widely used in various vehicles.

[0003] However, among the various electro-hydraulic braking systems currently proposed, none offer a completely reliable multi-circuit system to meet the high demands of mid-size off-road vehicles for braking performance and frequency. For example, the existing patent, titled "Control Method for a Dual-Circuit Electro-hydraulic Braking System with Two Channels" (publication number CN113650595A), describes a system where two independent channels of electro-hydraulic braking control the left and right wheel sides respectively. If one channel fails, the braking performance on that side of the vehicle completely fails, easily causing skidding or tilting and impacting driving safety. Furthermore, this system relies solely on its own motor to provide hydraulic pressure in the master cylinder, failing to meet the high braking performance and frequent braking requirements of mid-size off-road vehicles. Its functional expandability is also poor, unable to be extended to three- or four-axle off-road vehicles. Finally, during emergency braking, the braking system cannot provide additional power, failing to meet the braking force demands in emergency braking situations. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an electronic hydraulic braking system and control method for a medium-sized off-road vehicle.

[0005] This invention is achieved using the following technical solution:

[0006] An electronic hydraulic braking system for a medium-sized off-road vehicle includes a brake fluid reservoir. One end of the brake fluid reservoir is connected to the brake master cylinder via a supply line, and the other end of the brake fluid reservoir is connected to the oil inlets of the front axle power unit and the rear axle power unit via a supply line. The brake master cylinder is connected to a hydraulic power assist unit via an inlet line. The oil outlets of the front axle power unit and the rear axle power unit are respectively connected to the hydraulic power assist unit via booster lines. The hydraulic power assist unit is connected to the wheel brake cylinders via a hydraulic ESC regulator.

[0007] The master cylinder is provided with a front chamber inlet, a rear chamber inlet, a front chamber outlet, and a rear chamber outlet. One end of the brake fluid reservoir is connected to the front chamber inlet and the rear chamber inlet respectively through an inlet pipe. The front chamber outlet and the rear chamber outlet are respectively connected to the hydraulic power assist unit. The master cylinder is also connected to the brake pedal.

[0008] Preferably, the hydraulic power assist unit is provided with a first pilot oil inlet, a second pilot oil inlet, a front axle oil inlet, a rear axle oil inlet, a front axle oil outlet, and a rear axle oil outlet. The front cavity outlet is connected to the first pilot oil inlet through an inlet pipe, and the rear cavity outlet is connected to the second pilot oil inlet through an inlet pipe.

[0009] The oil outlet of the front axle power unit is connected to the oil inlet of the front axle via a booster pipe, and the oil outlet of the rear axle power unit is connected to the oil inlet of the rear axle via a booster pipe. The oil outlets of the front axle and the rear axle are respectively connected to the hydraulic ESC regulator.

[0010] Preferably, the hydraulic ESC regulator is provided with a hydraulic inlet and a hydraulic outlet, the hydraulic inlet being connected to the front axle outlet and the rear axle outlet respectively, the wheel brake cylinder including a front axle brake cylinder and a rear axle brake cylinder connected, and the hydraulic outlet being connected to the front axle brake cylinder and the rear axle brake cylinder respectively.

[0011] Preferably, both the front axle power unit and the rear axle power unit are equipped with high-voltage accumulators.

[0012] An electro-hydraulic control method for a medium-sized off-road vehicle, applied to any of the electro-hydraulic braking systems described above, including a drive-by-wire mode:

[0013] When the vehicle is in drive-by-wire mode, the vehicle control unit (VCU) transmits the braking deceleration and braking pressure values ​​to the hydraulic power assist unit and the hydraulic ESC regulator via bus commands. At the same time, the hydraulic power assist unit and the hydraulic ESC regulator adjust the braking force of each wheel according to the wheel slip ratio and wheel speed information. By controlling the solenoid valves of the hydraulic ESC regulator, a certain pressure of brake fluid is output to the wheel brake cylinders.

[0014] Preferably, a manual mode is also included:

[0015] When the vehicle is in manual mode, the electronic control unit controller of the hydraulic power assist unit collects signals from the accelerator pedal and brake pedal to determine the braking pressure required by the wheel brake cylinders. It then controls the hydraulic pressure of the wheel brake cylinders by driving the solenoid valves of the hydraulic ESC regulator to achieve different braking intensities. At the same time, the braking signals, braking pressure, and vehicle speed information are communicated with the vehicle's VCU controller via bus commands.

[0016] Preferably, the brake pedal is equipped with a brake displacement sensor. When the slope of the brake displacement sensor changes rapidly, it is identified as the driver's intention to brake urgently. At this time, the high-pressure accumulator replenishes the braking pressure to meet the need for rapid braking. At the same time, the hydraulic ESC regulator distributes and adjusts the braking pressure of the wheel brake cylinders.

[0017] Preferably, when the brake fluid reservoir or the brake fluid reservoir and the fluid supply lines to the front axle power unit and the rear axle power unit fail, the high-pressure accumulator replenishes the braking pressure to meet the emergency braking requirements, while the hydraulic ESC regulator distributes and adjusts the braking pressure of the wheel brake cylinders.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] By creating an independent dual-channel circuit for the master cylinder, independent control of the front and rear axle braking circuits is achieved. Through a hydraulic power assist unit and a hydraulic ESC adjuster, a dual-circuit hydraulic control unit is formed, allowing independent control of the hydraulic pressure in the front and rear axle brake wheel cylinders. This effectively enables adjustable braking force at each wheel, helping the driver maintain a safe speed and improving braking safety. To prevent skidding and veering, the hydraulic ESC adjuster ensures that the vehicle's steering and braking systems function normally during emergency braking, further enhancing driving safety.

[0020] The front axle power unit and the rear axle power unit are equipped with high-pressure accumulators to provide sufficient oil pressure for the braking system, thereby increasing the braking pressure and braking response time required by the vehicle during driving.

[0021] It can be extended to three- and four-axle off-road vehicles, thereby increasing the space for the vehicle's superstructure and improving the commonality of the vehicle chassis. Attached Figure Description

[0022] Figure 1 This is a connection diagram of the present invention.

[0023] In the diagram: 1. Brake fluid reservoir; 2. Brake master cylinder; 21. Front chamber inlet; 22. Rear chamber inlet; 23. Front chamber outlet; 24. Rear chamber outlet; 3. Front axle power unit; 4. Rear axle power unit; 5. Hydraulic power steering unit; 51. First pilot inlet; 52. Second pilot inlet; 53. Front axle inlet; 54. Rear axle inlet; 55. Front axle outlet; 56. Rear axle outlet; 6. Hydraulic ESC regulator; 61. Hydraulic inlet; 62. Hydraulic outlet; 7. Wheel brake cylinder; 71. Front axle brake cylinder; 72. Rear axle brake cylinder. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0025] Example 1

[0026] An electronic hydraulic braking system for a medium-sized off-road vehicle includes a brake fluid reservoir 1. One end of the brake fluid reservoir 1 is connected to the master cylinder 2 via a supply line, and the other end of the brake fluid reservoir 1 is connected to the oil inlets of the front axle power unit 3 and the rear axle power unit 4 via a supply line. The master cylinder 2 is connected to a hydraulic power assist unit 5 via an inlet line. The oil outlets of the front axle power unit 3 and the rear axle power unit 4 are respectively connected to the hydraulic power assist unit 5 via pressurization lines. The hydraulic power assist unit 5 is connected to the wheel brake cylinders 7 via a hydraulic ESC regulator 6.

[0027] The master cylinder 2 is provided with a front chamber inlet 21, a rear chamber inlet 22, a front chamber outlet 23, and a rear chamber outlet 24. One end of the brake fluid reservoir 1 is connected to the front chamber inlet 21 and the rear chamber inlet 22 respectively through an inlet pipe. The front chamber outlet 23 and the rear chamber outlet 24 are respectively connected to the hydraulic power assist unit 5. The master cylinder 2 is also connected to the brake pedal.

[0028] By separating the front and rear chambers, the master cylinder 2 achieves a safety redundancy design for the entire vehicle's braking system, ensuring that the front and rear axle brake lines are two independent circuits. When one brake line fails, the other brake line can provide emergency braking force, ensuring the vehicle can stop smoothly and guaranteeing driving safety.

[0029] When mechanical conditions or electronic control functions fail, the driver can press the brake pedal, and the brake master cylinder 2 will pump brake fluid into the hydraulic power assist unit 5 through the front chamber outlet 23 and the rear chamber outlet 24 of the brake master cylinder 2 under the action of driving force.

[0030] The hydraulic power assist unit 5 is provided with a first pilot oil inlet 51, a second pilot oil inlet 52, a front axle oil inlet 53, a rear axle oil inlet 54, a front axle oil outlet 55 and a rear axle oil outlet 56. The front cavity outlet 23 is connected to the first pilot oil inlet 51 through an inlet pipe, and the rear cavity outlet 24 is connected to the second pilot oil inlet 52 through an inlet pipe.

[0031] The oil outlet of the front axle power unit 3 is connected to the front axle oil inlet 53 through a booster pipe, the oil outlet of the rear axle power unit 4 is connected to the rear axle oil inlet 54 through a booster pipe, and the front axle oil outlet 55 and the rear axle oil outlet 56 are respectively connected to the hydraulic ESC regulator 6.

[0032] The oil outlets of the front axle power unit 3 and the rear axle power unit 4 are connected to the front axle oil inlet 53 and the rear axle oil inlet 54 respectively through pressurization pipelines to pressurize and provide high-pressure brake fluid to meet the braking energy requirements of the medium-sized off-road vehicle during driving.

[0033] The hydraulic ESC regulator 6 is provided with a hydraulic inlet 61 and a hydraulic outlet 62. The hydraulic inlet 61 is connected to the front axle outlet 55 and the rear axle outlet 56 respectively. The wheel brake cylinder 7 includes a front axle brake cylinder 71 and a rear axle brake cylinder 72 connected together. The hydraulic outlet 62 is connected to the front axle brake cylinder 71 and the rear axle brake cylinder 72 respectively.

[0034] Both the front axle power unit 3 and the rear axle power unit 4 are equipped with high-voltage accumulators.

[0035] Example 2

[0036] An electro-hydraulic control method for a medium-sized off-road vehicle, applied to any of the above-mentioned electro-hydraulic braking systems, including drive-by-wire mode:

[0037] When the vehicle is in drive-by-wire mode, the vehicle control unit (VCU) transmits the braking deceleration and braking pressure values ​​to the hydraulic power assist unit 5 and the hydraulic ESC regulator 6 via bus commands. At the same time, the hydraulic power assist unit 5 and the hydraulic ESC regulator 6 adjust the braking force of each wheel according to the wheel slip ratio and wheel speed information. By controlling the solenoid valve of the hydraulic ESC regulator 6, a certain pressure of brake fluid is output to the wheel brake cylinder 7 to realize drive-by-wire pressure boosting, pressure holding, and pressure reduction control.

[0038] Also includes a manual mode:

[0039] When the vehicle is in manual mode, the electronic control unit controller of the hydraulic power assist unit 5 collects the signals from the accelerator pedal and the brake pedal to determine the braking pressure required by the wheel brake cylinder 7. It then controls the hydraulic pressure of the wheel brake cylinder 7 by driving the solenoid valve of the hydraulic ESC regulator 6 to achieve different braking intensities. At the same time, the braking signal, braking pressure, and vehicle speed information are communicated with the vehicle VCU controller via bus commands.

[0040] The brake pedal is equipped with a brake displacement sensor. When the slope of the brake displacement sensor changes rapidly, it is identified as the driver's intention to brake urgently. At this time, the high-pressure accumulator replenishes the braking pressure to meet the need for rapid braking. At the same time, the hydraulic ESC regulator 6 distributes and adjusts the braking pressure of the wheel brake cylinders 7.

[0041] The hydraulic ESC regulator 6 can distribute and adjust the braking pressure of the wheel brake cylinders 7 to prevent wheel lock-up and improve driving stability.

[0042] When the brake fluid reservoir 1 or the brake fluid reservoir 1 and the fluid supply line to the front axle power unit 3 and the rear axle power unit 4 fail, the high-pressure accumulator replenishes the braking pressure to meet the emergency braking needs. At the same time, the hydraulic ESC regulator 6 distributes and adjusts the braking pressure of the wheel brake cylinders.

Claims

1. An electro-hydraulic braking system for a medium-sized off-road vehicle, characterized in that, The system includes a brake fluid reservoir (1), one end of which is connected to the master cylinder (2) via a fluid supply line, and the other end of which is connected to the inlet of the front axle power unit (3) and the rear axle power unit (4) via a fluid supply line. The master cylinder (2) is connected to the hydraulic power assist unit (5) via a fluid inlet line. The outlets of the front axle power unit (3) and the rear axle power unit (4) are connected to the hydraulic power assist unit (5) via booster lines. The hydraulic power assist unit (5) is connected to the wheel brake cylinder (7) via a hydraulic ESC regulator (6). The master cylinder (2) is provided with a front chamber inlet (21), a rear chamber inlet (22), a front chamber outlet (23), and a rear chamber outlet (24). One end of the brake fluid reservoir (1) is connected to the front chamber inlet (21) and the rear chamber inlet (22) respectively through an inlet pipe. The front chamber outlet (23) and the rear chamber outlet (24) are respectively connected to the hydraulic power assist unit (5). The master cylinder (2) is also connected to the brake pedal.

2. The electro-hydraulic braking system for a medium-sized off-road vehicle according to claim 1, characterized in that, The hydraulic power assist unit (5) is provided with a first pilot oil inlet (51), a second pilot oil inlet (52), a front axle oil inlet (53), a rear axle oil inlet (54), a front axle oil outlet (55) and a rear axle oil outlet (56). The front cavity outlet (23) is connected to the first pilot oil inlet (51) through an inlet pipe, and the rear cavity outlet (24) is connected to the second pilot oil inlet (52) through an inlet pipe. The oil outlet of the front axle power unit (3) is connected to the front axle oil inlet (53) through a booster pipe, the oil outlet of the rear axle power unit (4) is connected to the rear axle oil inlet (54) through a booster pipe, and the front axle oil outlet (55) and the rear axle oil outlet (56) are respectively connected to the hydraulic ESC regulator (6).

3. The electro-hydraulic braking system for a medium-sized off-road vehicle according to claim 2, characterized in that, The hydraulic ESC regulator (6) is provided with a hydraulic inlet (61) and a hydraulic outlet (62). The hydraulic inlet (61) is connected to the front axle outlet (55) and the rear axle outlet (56) respectively. The wheel brake cylinder (7) includes a front axle brake cylinder (71) and a rear axle brake cylinder (72) connected together. The hydraulic outlet (62) is connected to the front axle brake cylinder (71) and the rear axle brake cylinder (72) respectively.

4. The electro-hydraulic braking system for a medium-sized off-road vehicle according to claim 2, characterized in that, Both the front axle power unit (3) and the rear axle power unit (4) are equipped with high-voltage accumulators.

5. A method for electro-hydraulic control of a medium-sized off-road vehicle, applied to the electro-hydraulic braking system according to any one of claims 1-4, characterized in that, Includes drive-by-wire mode: When the vehicle is in drive-by-wire mode, the vehicle control unit (VCU) transmits the braking deceleration and braking pressure values ​​to the hydraulic power assist unit (5) and the hydraulic ESC regulator (6) via bus commands. At the same time, the hydraulic power assist unit (5) and the hydraulic ESC regulator (6) adjust the braking force of each wheel according to the wheel slip ratio and wheel speed information. By controlling the solenoid valve provided in the hydraulic ESC regulator (6), a certain pressure of brake fluid is output to the wheel brake cylinder (7).

6. The electro-hydraulic control method for a medium-sized off-road vehicle according to claim 5, characterized in that, Also includes a manual mode: When the vehicle is in manual mode, the electronic control unit controller of the hydraulic power assist unit (5) collects the signals of the accelerator pedal and the brake pedal to determine the braking pressure required by the current wheel brake cylinder (7), and controls the hydraulic pressure of the wheel brake cylinder (7) by driving the solenoid valve of the hydraulic ESC regulator (6) to achieve different braking intensities. At the same time, the braking signal, braking pressure and vehicle speed information are communicated with the vehicle VCU controller through bus commands.

7. The electro-hydraulic control method for a medium-sized off-road vehicle according to claim 6, characterized in that, The brake pedal is equipped with a brake displacement sensor. When the slope of the brake displacement sensor changes rapidly, it is identified as the driver's intention to brake urgently. At this time, the high-pressure accumulator replenishes the braking pressure to meet the need for rapid braking. At the same time, the hydraulic ESC regulator (6) distributes and adjusts the braking pressure of the wheel brake cylinder (7).

8. The electro-hydraulic control method for a medium-sized off-road vehicle according to claim 7, characterized in that, When the brake fluid reservoir (1) or the brake fluid reservoir (1) fails to supply fluid to the front axle power unit (3) and the rear axle power unit (4), the high-pressure accumulator replenishes the braking pressure to meet the emergency braking requirements. At the same time, the hydraulic ESC regulator (6) distributes and adjusts the braking pressure of the wheel brake cylinders.

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