Method and system for preventing brake deviation during failure of hydraulic brake circuit and vehicle

Abstract

The invention discloses a method and a system for preventing brake deviation during failure of a hydraulic brake loop and a vehicle, and the method comprises the following steps: S1, in the running process of the vehicle, detecting whether the vehicle has a failure fault of the hydraulic brake loop or not, and if the detection result is yes and only one hydraulic brake loop fails, executing the step S2; s2, brake pressure distributed to front wheels and rear wheels by a normal hydraulic brake circuit is adjusted, so that brake torque acting on the front wheels and the rear wheels by front and rear calipers is the same, and the stability of the vehicle is improved; and meanwhile, the method is realized on the basis of not increasing any hardware cost, and all adopted parts are parts carried by the vehicle, so that the cost is greatly saved.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle brake control, and more specifically, the present invention relates to a method, system and vehicle for preventing brake deviation when a hydraulic brake circuit fails. Background Art

[0002] At present, with the increasing attention paid to energy conservation and environmental protection, the use of electric vehicles is gradually increasing. The braking system is one of the most important systems in a car.

[0003] Most existing passenger vehicle brake system pipelines use an "X"-shaped arrangement for hydraulic braking, that is, the left front wheel and the right rear wheel share a hydraulic brake circuit, and the right front wheel and the left rear wheel share a hydraulic brake circuit, which act on the wheels through calipers to generate the deceleration required by the vehicle.

[0004] The problem with the above braking method is that when a hydraulic brake circuit fails, after the driver steps on the brake pedal, the vehicle generates a yaw moment due to the different braking coefficients of the front and rear wheels, resulting in different braking torques acting on the front and rear wheels, causing the vehicle to become unstable, resulting in traffic safety accidents, and posing a hidden danger to the driver's personal and property safety. Summary of the invention

[0005] The present invention provides a method for preventing brake deviation when a hydraulic brake circuit fails, aiming to improve the above-mentioned problem.

[0006] The present invention is implemented as follows: a method for preventing brake deviation when a hydraulic brake circuit fails, the method comprising the following steps:

[0007] S1. During the driving process of the vehicle, detect whether the vehicle has a hydraulic brake circuit failure fault. If the detection result is yes and only one hydraulic brake circuit fails, execute step S2;

[0008] S2. Adjust the brake pressure distributed to the front and rear wheels by the normal hydraulic brake circuit so that the front and rear calipers exert the same braking torque on the front and rear wheels, thus avoiding the vehicle from running off the track due to different braking torques of the front and rear wheels.

[0009] Furthermore, the method for distributing the braking pressure of the front wheels and the rear wheels is as follows:

[0010] Collect the brake pressure P applied by the driver on the brake pedal and calculate the braking torque T under the brake pressure;

[0011] The braking torque T is evenly distributed to the front and rear wheels.

[0012] Furthermore, the front wheel braking coefficient K f Greater than the rear wheel braking coefficient K r .

[0013] Furthermore, the rear wheel braking pressure is increased and the front wheel braking pressure is reduced so that the braking torques of the front and rear wheels are the same.

[0014] Furthermore, the calculation formulas for the brake pressure of the front and rear wheels are as follows:

[0015] P f =P*(K f +K r ) / (2*K f );

[0016] P r =P*(K f +K r ) / (2*K r );

[0017] Among them, P f , P r Respectively represent the front wheel and rear wheel brake pressure.

[0018] Furthermore, the method for detecting the failure of the hydraulic brake circuit is as follows:

[0019] The vehicle status information is detected in real time to detect whether there is hydraulic brake circuit failure fault information in the vehicle status information. If so, it is determined that there is a hydraulic brake circuit failure fault.

[0020] Furthermore, when both hydraulic brake circuits are normal, the brake pressures of the front and rear wheels are not adjusted.

[0021] The present invention is implemented as follows: a system for preventing brake deviation when a hydraulic brake circuit fails, the system comprising:

[0022] Two hydraulic brake circuits, each of which is provided with a solenoid valve, and the front wheel brake pressure and the rear wheel brake pressure on the corresponding hydraulic brake circuit are adjusted by turning the solenoid valve on and off; a transmission mechanism, the two ends of the transmission mechanism are respectively connected to the output shaft of the drive motor and the piston rod of the hydraulic cylinder; a hydraulic brake controller, which is in communication connection with the drive motor and the solenoid valve;

[0023] The hydraulic brake controller uses the method for preventing brake deviation when the hydraulic brake circuit fails to control the front wheel brake pressure and the rear wheel brake pressure on the hydraulic brake circuit.

[0024] The present invention is implemented in a vehicle, on which the above-mentioned anti-brake deviation system when the hydraulic brake circuit fails is integrated.

[0025] When one hydraulic brake circuit fails or fails, the present invention keeps the braking torques of the front wheels and the rear wheels the same by adjusting the braking pressures of the front wheels and the rear wheels, thereby increasing the stability of the vehicle. At the same time, the present invention is achieved without increasing any hardware costs, and all the components used are components that come with the vehicle itself, which greatly saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a method for preventing brake deviation when a hydraulic brake circuit fails provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0028] Figure 1 A flow chart of a method for preventing brake deviation when a hydraulic brake circuit fails provided by an embodiment of the present invention, the method specifically comprises the following steps:

[0029] S1. During the driving process of the vehicle, detect whether the vehicle has a hydraulic brake circuit failure fault. If the detection result is yes, execute step S2;

[0030] During the driving process of the vehicle, the vehicle status information is detected in real time to detect whether there is hydraulic brake circuit failure fault information in the vehicle status information. If so, it is determined that there is a hydraulic brake circuit failure fault. If not, there is no hydraulic brake circuit failure fault. Of course, the hydraulic brake circuit failure fault here refers to the failure of one hydraulic brake circuit in the braking system, and the other hydraulic brake circuit is normal. If both hydraulic brake circuits fail, the braking system fails and the vehicle's braking function cannot be realized. If both hydraulic brake circuits are normal, the vehicle adopts the existing hydraulic braking strategy without adjusting the braking pressure of the front and rear wheels.

[0031] S2. Adjust the brake pressure distributed to the front and rear wheels by the normal hydraulic brake circuit so that the front and rear calipers exert the same braking torque on the front and rear wheels, thus avoiding the vehicle from running off the track due to different braking torques of the front and rear wheels.

[0032] Generally speaking, the braking coefficient of the front wheels is greater than that of the rear wheels. Therefore, the braking torque allocated to the front wheels is greater than that of the rear wheels. When both hydraulic brake circuits are normal, the yaw moments generated by the different braking torques of the front and rear wheels cancel each other out, and the vehicle will not generate lateral swing force. However, after one hydraulic brake circuit fails, the yaw moments generated by the different braking torques of the front and rear wheels cannot cancel each other out, and the vehicle generates lateral swing force. At this time, it is necessary to balance the braking torques of the front and rear wheels.

[0033] In the embodiment of the present invention, the method for distributing the braking pressure of the front wheels and the rear wheels is specifically as follows:

[0034] Collect the brake pressure P applied by the driver on the brake pedal and calculate the braking torque T under the brake pressure;

[0035] In the embodiment of the present invention, when the driver brakes by stepping on the brake pedal, the hydraulic control system outputs the corresponding braking torque T based on the braking stroke of the brake pedal, that is, the braking pressure applied to the brake pedal. Since only one hydraulic brake circuit is normal and the front wheel braking coefficient is K f , the braking coefficient of the rear wheel is K r Therefore, the calculation formula of the braking torque T output by the hydraulic braking coefficient is as follows:

[0036] T=P*(K f +K r ).

[0037] Based on the front wheel braking coefficient K f , rear wheel braking coefficient K r Distribute the braking torque T evenly to the front and rear wheels.

[0038] To achieve even distribution of the braking torque to the front and rear wheels, the braking torque generated by the front and rear wheels is:

[0039] T f =T r =T / 2=P*(K f +K r ) / 2;

[0040] Among them, T f , T r Represent the braking torque of the front and rear wheels respectively.

[0041] Then, the braking torque T f , T r Corresponding front and rear wheel brake pressure P f , P r The calculation formula is as follows:

[0042] P f =P*(K f +K r ) / (2*K f );

[0043] P r =P*(K f +K r ) / (2*K r );

[0044] Hydraulic brake changes the front wheel brake pressure from P to Pf , the rear wheel brake pressure is increased from P to P r In the existing hydraulic brake system, due to the front wheel braking coefficient K f Greater than the rear wheel braking coefficient K r Therefore, the braking pressure of the front wheels is reduced and the braking pressure of the rear wheels is increased so that the braking torque generated by the front and rear wheels is the same, both T / 2.

[0045] When one hydraulic brake circuit fails or fails, the present invention keeps the braking torques of the front wheels and the rear wheels the same by adjusting the braking pressures of the front wheels and the rear wheels, thereby increasing the stability of the vehicle. At the same time, the present invention is achieved without increasing any hardware costs, and all the components used are components that come with the vehicle itself, which greatly saves costs.

[0046] The embodiment of the present invention further provides a system for preventing brake deviation when a hydraulic brake circuit fails, the system comprising:

[0047] Two hydraulic brake circuits, namely the first hydraulic brake circuit and the second hydraulic brake circuit, each of which is provided with a solenoid valve, and the front wheel brake pressure and the rear wheel brake pressure on the corresponding hydraulic brake circuit are adjusted by controlling the on-off of the solenoid valve. The first hydraulic brake circuit controls the calipers of the right front wheel and the left rear wheel, and the second hydraulic brake circuit controls the calipers of the right rear wheel and the left front wheel;

[0048] Transmission mechanism, the two ends of the transmission mechanism are respectively connected to the output shaft of the drive motor and the piston rod of the hydraulic cylinder; the hydraulic controller is connected to the drive motor and the solenoid valve for communication;

[0049] The hydraulic controller controls the front wheel braking pressure and the rear wheel braking pressure on the hydraulic braking circuit based on the above-mentioned anti-brake deviation method when the hydraulic braking circuit fails.

[0050] In the embodiment of the present invention, when one hydraulic brake circuit fails, the front wheel and rear wheel brake pressures P corresponding to the normal hydraulic brake circuits are f , P r The details are as follows:

[0051] P f =P*(K f +K r ) / (2*K f );

[0052] P r =P*(K f +K r ) / (2*K r );

[0053] When both hydraulic brake circuits are normal, the brake pressures of the two front wheels and the two rear wheels are the brake pressure P applied by the driver on the brake pedal.

[0054] When braking, the drive motor rotates, controlling the piston rod to move downward, increasing the pressure in the hydraulic cylinder, and squeezing the liquid in the hydraulic cylinder into the hydraulic brake circuit. At this time, the two solenoid valves on the faulty hydraulic brake circuit are in the closed state.

[0055] The present invention also provides a vehicle, which is integrated with the above-mentioned anti-brake deviation system when the hydraulic brake circuit fails. When the vehicle detects that one hydraulic brake circuit is faulty or fails, the braking torque of the front wheels and the rear wheels is kept the same by adjusting the braking pressure of the front wheels and the rear wheels, thereby increasing the stability of the vehicle. At the same time, the present invention is implemented without increasing any hardware costs, and all the components used are components that come with the vehicle itself, which greatly saves costs.

[0056] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for preventing brake deviation when a hydraulic brake circuit fails, characterized in that: The method comprises the following steps: S1. During the driving process of the vehicle, detect whether the vehicle has a hydraulic brake circuit failure fault. If the detection result is yes and only one hydraulic brake circuit fails, execute step S2; S2. Adjust the brake pressure distributed to the front and rear wheels by the normal hydraulic brake circuit so that the braking torques applied by the front and rear calipers on the front and rear wheels are the same.

2. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 1, characterized in that: The brake pressure distribution method of the front and rear wheels is as follows: Collect the brake pressure P applied by the driver on the brake pedal and calculate the braking torque T under the brake pressure; Distribute the braking torque T evenly to the front and rear wheels.

3. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 2, characterized in that: Front wheel braking coefficient K f Greater than the rear wheel braking coefficient K r .

4. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 3, characterized in that: Increase the rear wheel brake pressure and reduce the front wheel brake pressure to make the braking torque of the front and rear wheels the same.

5. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 4, characterized in that: The calculation formulas for the brake pressure of the front and rear wheels are as follows: P f =P*(K f +K r ) / (2*K f ); P r =P*(K f +K r ) / (2*K r ); Among them, P f , P r Respectively represent the front wheel and rear wheel brake pressure.

6. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 1, characterized in that: The specific detection method of hydraulic brake circuit failure is as follows: The vehicle status information is detected in real time to detect whether there is hydraulic brake circuit failure fault information in the vehicle status information. If so, it is determined that there is a hydraulic brake circuit failure fault.

7. The method for preventing brake deviation when the hydraulic brake circuit fails as claimed in claim 1, characterized in that: When both hydraulic brake circuits are normal, the brake pressure of the front and rear wheels is not adjusted.

8. A system for preventing brake deviation when a hydraulic brake circuit fails, characterized in that: The system comprises: Two hydraulic brake circuits, each of which is provided with a solenoid valve, and the front wheel brake pressure and the rear wheel brake pressure on the corresponding hydraulic brake circuit are adjusted by turning the solenoid valve on and off; a transmission mechanism, the two ends of the transmission mechanism are respectively connected to the output shaft of the drive motor and the piston rod of the hydraulic cylinder; a hydraulic brake controller, which is in communication connection with the drive motor and the solenoid valve; The hydraulic brake controller controls the front wheel brake pressure and the rear wheel brake pressure in the hydraulic brake circuit based on the anti-brake deviation method when the hydraulic brake circuit fails as described in any one of claims 1 to 7.

9. A vehicle, characterized in that: The vehicle is integrated with a brake deviation prevention system when the hydraulic brake circuit fails as described in claim 8.

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