Method for learning braking step threshold values of a sustained-action brake operated in braking steps, and braking system

Patent metadata

Field	Value
Publication number	US-11535213-B2
Application number	US-201816614805-A
Country	US
Kind code	B2
Filing date	Apr 26, 2018
Priority date	Jun 26, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A method for learning braking step threshold values of a sustained-action brake includes detecting a braking requirement setpoint, controlling the sustained-action brake with the braking requirement setpoint to generate a braking effect variable of the sustained-action brake, and detecting a sustained-action brake actual braking effect variable and a maximum sustained-action brake braking effect. The method additionally includes forming a braking effect variable coefficient that characterizes a ratio of the sustained-action brake actual braking effect variable and the maximum sustained-action brake braking effect variable that results from control of the sustained-action brake with the braking requirement setpoint, and assigning the braking effect variable coefficient to a braking step of the sustained-action brake such that each braking step is assigned only one braking effect variable. Additionally, the method includes storing the braking requirement setpoint that results in the braking effect variable coefficient.

First claim

The invention claimed is:

1. A method for carrying out braking steps of a commercial vehicle to learn braking step threshold values of a sustained-action brake of the commercial vehicle, the method comprising:
detecting a braking requirement setpoint;
controlling the sustained-action brake with the braking requirement setpoint to increase or reduce an actual deceleration of the commercial vehicle, thereby generating a braking effect variable of the sustained-action brake;
detecting a sustained-action brake actual braking effect variable and a maximum sustained-action brake braking effect, wherein the sustained-action brake actual braking effect variable characterizes the braking effect variable generated by the sustained-action brake as a result of controlling the sustained-action brake with the braking requirement setpoint, and wherein the maximum sustained-action brake braking effect variable characterizes a maximum braking effect variable that can be produced by the sustained-action brake during controlling of the sustained-action brake with the braking requirement setpoint;
forming a braking effect variable coefficient that characterizes a ratio of the sustained-action brake actual braking effect variable and the maximum sustained-action brake braking effect variable that results from controlling of the sustained-action brake with the braking requirement setpoint;
assigning the braking effect variable coefficient to a braking step of the sustained-action brake such that each braking step is assigned only one braking effect variable; and
storing the braking requirement setpoint that results in the braking effect variable coefficient, as the braking step threshold value of the braking step to which the braking effect variable coefficient is assigned, wherein the braking step threshold value indicates the braking requirement setpoint at which the respective braking step is activated or deactivated.

2. The method as claimed in claim 1 , wherein a braking step activation threshold value indicates from which values of the braking requirement setpoint the respective braking step is activated in the case of an increase in the vehicle actual deceleration as a result of control with this braking requirement setpoint, and a braking step deactivation threshold value indicates from which values of the braking requirement setpoint the respective braking step is deactivated in the case of a reduction of the vehicle actual deceleration as a result of control with this braking requirement setpoint.

3. The method as claimed in claim 2 , wherein the braking step activation threshold value assigned to a braking step is not equal to the braking step deactivation threshold value that is assigned to the same braking step.

4. The method as claimed in claim 2 , wherein storing the braking requirement setpoint as a braking step activation threshold value of a certain braking step takes place only if a braking step activation threshold is not already stored for this braking step that is smaller than the braking requirement setpoint, and/or for which the respective braking step has already been activated previously if the vehicle actual deceleration increases as a result of control of the sustained-action brake with this stored braking step activation threshold value.

5. The method according to claim 2 , wherein storing the braking requirement setpoint as a braking step deactivation threshold value of a certain braking step takes place only if this braking step has not already been assigned a braking step deactivation threshold value which is smaller than the braking requirement setpoint and/or for which later deactivation of the same braking step is carried out in the event of a reduction in the actual vehicle deceleration due to control of the sustained-action brake with this stored braking step deactivation threshold value.

6. The method according to claim 2 , wherein the activation of a higher braking step in which a higher sustained-action brake actual braking effect variable is generated is concluded if the braking effect variable coefficient increases as a result of control of the sustained-action brake with a certain braking requirement setpoint and that deactivation of the braking step and activation of a lower braking step in which a lower sustained-action brake actual braking effect variable is produced is concluded if the braking effect variable coefficient is reduced as a result of control of the sustained-action brake with a specific braking requirement setpoint.

7. The method according to claim 1 , wherein at least one variable selected from the group consisting of a vehicle deceleration setpoint, a sustained-action brake setpoint braking torque and/or a sustained-action brake setpoint braking force is defined as a braking requirement setpoint.

8. The method according to claim 1 , wherein a number of braking steps is learned depending on a number of different braking action variable coefficients assigned to the respective braking steps.

9. The method according to claim 1 , wherein the braking effect variable coefficient of a respective braking step is also stored.

10. The method according to claim 1 , wherein the sustained-action brake actual braking effect variable is caused by a sustained-action brake actual braking torque generated by the sustained-action brake in the respective braking step and the maximum sustained-action brake braking effect variable is caused by a maximum producible sustained-action brake braking torque during control of the sustained-action brake with the braking requirement setpoint, or
the sustained-action brake actual braking effect variable is caused by a sustained-action brake actual braking force generated by the sustained-action brake in the respective braking step and the maximum sustained-action brake braking effect variable is caused by a maximum producible sustained-action brake braking force generated with the sustained-action brake during control with the braking requirement setpoint.

11. The method according to claim 1 , wherein each braking step is assigned an index, wherein the index is determined according to the braking effect variable coefficient in such a way that the braking steps are determined depending on the level of the sustained-action brake actual braking effect variable generated in the respective braking step.

12. The method according to claim 1 , wherein the braking requirement setpoint is specified in the form of an ascending and/or descending ramp and forming a braking effect variable coefficient, assigning the braking effect variable coefficient to a braking step of the sustained-action brake and storing the braking requirement setpoint as the braking step threshold value of that braking step assigned to the braking effect variable coefficient are carried out for each of the braking requirement setpoints with which the sustained-action brake is controlled on the rising and/or descending ramp.

13. The method as claimed in claim 12 , wherein the descending ramp runs between a minimum sustained-action brake braking effect variable and a reference braking effect variable of the sustained-action brake in the direction of an increase in the vehicle actual deceleration and the ascending ramp runs between the reference braking effect variable and the minimum sustained-action brake braking effect variable in the direction of a reduction in the vehicle actual deceleration, wherein the reference braking effect variable characterizes the maximum producible braking effect variable of the sustained-action brake regardless of the control of the sustained-action brake with the braking requirement setpoint.

14. The meth

Assignees

• Wabco Gmbh
• Zf Cv Systems Europe Bv

Inventors

• Hanslik Daniel
• Kallenbach Stephan
• Ragab Ahmed

Classifications

• B60T1/087 Primary

  in hydrodynamic, i.e. non-positive displacement, retarders · CPC title

• B60T10/04

  with hydrostatic brake · CPC title

• B60T13/662

  characterised by specified functions of the control system components · CPC title

• B60T10/02

  with hydrodynamic brake · CPC title

• B60T1/093

  in hydrostatic, i.e. positive displacement, retarders · CPC title