Vehicle and braking method and device therefor

Patent metadata

Field	Value
Publication number	US-11964591-B2
Application number	US-202017639255-A
Country	US
Kind code	B2
Filing date	Aug 27, 2020
Priority date	Aug 30, 2019
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A braking method for a vehicle is provided. The method includes the following steps: obtaining a first state information of the vehicle, where the first state information includes a vehicle mass and a deceleration required by braking; calculating a braking torque required by the vehicle according to the first state information, and controlling an output of an electric braking torque according to the braking torque required by the vehicle; obtaining a current vehicle speed of the vehicle and a maximum electric braking exit speed; and; controlling, if the deceleration required by braking of the vehicle changes to zero, the vehicle to unload the electric braking torque when the current vehicle speed is less than the maximum electric braking exit speed. A braking device for a vehicle and a vehicle are further provided.

First claim

What is claimed is:

1. A braking method for a vehicle, comprising the following steps:
obtaining a first state information of the vehicle, wherein the first state information comprises a vehicle mass and a deceleration required by braking;
calculating a braking torque required by the vehicle according to the first state information, and controlling an output of an electric braking torque according to the braking torque required by the vehicle;
obtaining a current vehicle speed of the vehicle and a maximum electric braking exit speed;
the deceleration required by braking of the vehicle changing to zero;
the current vehicle speed being less than the maximum electric braking exit speed; and
controlling the vehicle to unload the electric braking torque.

2. The braking method for a vehicle according to claim 1 , wherein the controlling the vehicle to unload the electric braking torque comprises:
obtaining an unloading rate of the electric braking torque and a comfortable unloading rate of the electric braking torque;
the deceleration required by braking of the vehicle changes to zero;
controlling the vehicle to unload the electric braking torque at the comfortable unloading rate of the electric braking torque,
the current vehicle speed being less than the maximum electric braking exit speed, and
controlling the vehicle to unload the electric braking torque at the unloading rate of the electric braking torque.

3. The braking method for a vehicle according to claim 1 , wherein the step of obtaining the maximum electric braking exit speed comprises:
obtaining a maximum allowable gradient, a maximum allowable vehicle mass, and a maximum allowable deceleration required by braking of the vehicle; and
calculating the maximum electric braking exit speed according to the maximum allowable vehicle mass, the maximum allowable deceleration required by braking, and the maximum allowable gradient.

4. The braking method for a vehicle according to claim 3 , wherein the calculating the maximum electric braking exit speed according to the maximum allowable vehicle mass, the maximum allowable deceleration required by braking, and the maximum allowable gradient comprises:
calculating a maximum allowable braking torque of the vehicle according to the maximum allowable vehicle mass and the maximum allowable deceleration required by braking; and
calculating the maximum electric braking exit speed according to the maximum allowable braking torque of the vehicle, the maximum allowable deceleration required by braking, and the maximum allowable gradient.

5. The braking method for a vehicle according to claim 4 , wherein the calculating the maximum electric braking exit speed according to the maximum allowable braking torque of the vehicle, the maximum allowable deceleration required by braking, and the maximum allowable gradient comprises:
obtaining an unloading rate of the electric braking torque and a current ground adhesion coefficient; and
calculating the maximum electric braking exit speed according to the maximum allowable braking torque of the vehicle, the unloading rate of the electric braking torque, the maximum allowable deceleration required by braking, the current ground adhesion coefficient, and the maximum allowable gradient.

6. The braking method for a vehicle according to claim 5 , wherein the calculating the maximum electric braking exit speed according to the maximum allowable braking torque of the vehicle, the unloading rate of the electric braking torque, the maximum allowable deceleration required by braking, the current ground adhesion coefficient, and the maximum allowable gradient comprises:
calculating a maximum allowable unloading time of the electric braking torque according to the maximum allowable braking torque of the vehicle and the unloading rate of the electric braking torque;
calculating a ground deceleration according to the current ground adhesion coefficient;
calculating a maximum allowable gradient deceleration according to the maximum allowable gradient; and
calculating the electric braking exit speed according to the unloading time of the electric braking torque, the deceleration required by braking, the ground deceleration, and the gradient deceleration.

7. The braking method for a vehicle according to claim 5 , further comprising:
obtaining a current gradient of the vehicle;
calculating an electric braking exit speed according to the braking torque required by the vehicle, the deceleration required by braking, and the current gradient;
the electric braking exit speed being less than zero and the current vehicle speed being less than the maximum electric braking exit speed; and
controlling the vehicle to unload the electric braking torque.

8. The braking method for a vehicle according to claim 6 , further comprising:
determining whether to control the vehicle to apply a mechanical braking torque according to the current vehicle speed, the braking torque required by the vehicle, the deceleration required by braking, and the current gradient.

9. The braking method for a vehicle according to claim 8 , wherein the determining whether to control the vehicle to a mechanical braking torque according to the current vehicle speed, the braking torque required by the vehicle, the deceleration required by braking, and the current gradient comprises:
the current gradient being not zero,
calculating a mechanical braking application speed according to the braking torque required by the vehicle, the deceleration required by braking, and the current gradient,
the current vehicle speed being less than the mechanical braking application speed, and
controlling the vehicle to apply the mechanical braking torque.

10. The braking method for a vehicle according to claim 9 , wherein the controlling the vehicle to apply the mechanical braking torque comprises:
obtaining an unloading rate of the electric braking torque, and controlling the vehicle to apply the mechanical braking torque according to the unloading rate of the electric braking torque; or obtaining a current electric braking torque, and controlling the vehicle to apply the mechanical braking torque according to the braking torque required by the vehicle and the current electric braking torque.

11. The braking method for a vehicle according to claim 9 , wherein the mechanical braking torque is provided by a hydraulic brake system, and the controlling the vehicle to apply the mechanical braking torque comprises:
obtaining a second state information of the vehicle, wherein the second state information comprises a kinetic friction coefficient, a brake disc radius, and a clamp port area; and
controlling the hydraulic brake system to apply a hydraulic brake pressure, to apply the mechanical braking torque according to the unloading rate of the electric braking torque, the first state information, and the second state information; or controlling the hydraulic brake system to apply the hydraulic brake pressure, to apply the mechanical braking torque according to the braking torque required by the vehicle, the current electric braking torque, the first state information, and the second state information.

12. The braking method for a vehicle according to claim 8 , wherein the determining whether to control the vehicle to unload the electric braking torque, and whether to control the vehicle to apply the mechanical braking torque according to the current vehicle speed, the braking torque required by the vehicle, the deceleration required by braking, and the current gradient further comprises:
the current gradient being zero, and the current vehicle speed of the vehicle being zero,

Assignees

• Byd Co Ltd

Inventors

• Ma Dong
• Wang Lu
• Li Daolin

Classifications

• B60L7/18 Primary

  Controlling the braking effect (B60L7/12, B60L7/14, B60L7/16 take precedence) · CPC title

• B60L7/26

  Controlling the braking effect · CPC title

• B60T8/3215

  Systems characterised by having means acting on components of the drive line, e.g. retarder, clutch or differential gear (B60T8/322 takes precedence) · CPC title

• B60T8/58

  responsive to speed and another condition or to plural speed conditions · CPC title

• B60T13/586

  the retarders being of the electric type · CPC title