Method for piloting a braking system of a vehicle, braking system and vehicle comprising such a braking system

Patent metadata

Field	Value
Publication number	US-10046746-B2
Application number	US-201415317178-A
Country	US
Kind code	B2
Filing date	Jul 2, 2014
Priority date	Jul 2, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A method allows piloting a braking system of a vehicle, the braking system including at least a pair of coupled brake actuators, that includes a pneumatic actuator supplied with a compressed air tank pressurized by a compressor, and an electric actuator. The method includes steps including a) measuring the air pressure of the air tank, b) if the air pressure measured at step a) is inferior to a first threshold value, assessing whether the compressor is able to build up the air pressure of the air tank, c) if the result of the assessment performed at step b) is that the compressor is unable to build up the air pressure of the air tank, operating the braking system in a degraded mode wherein at least the electric actuator is used in case of braking, and d) if the air pressure measured at step a) is inferior to a second threshold value, that is lower than the first threshold value, and if the compressor is unable to build up the air pressure of the air tank, using only the electric actuator in case of new braking actions.

First claim

The invention claimed is:

1. A method for piloting a braking system of a vehicle, the braking system comprising at least a pair of coupled brake actuators, the coupled brake actuators comprising a pneumatic brake actuator supplied with compressed air coming from an air tank that is pressurized by a compressor and an electric brake actuator, the method comprising:
a) measuring the air pressure of the air tank,
b) if the air pressure measured at step a) is less than a first threshold value, assessing whether the compressor is able to build up the air pressure in the air tank,
c) after determining that the result of the assessment performed at step b) is that the compressor is unable to build up the air pressure of the air tank, operating the braking system in a degraded mode wherein at least the electric brake actuator is used in case of new braking actions,
d) after determining that the air pressure measured at step a) is less than a second threshold value, the second threshold value being lower than the first threshold value, and if, according to the result of step b), the compressor is unable to build up the air pressure of the air tank, using only the electric brake actuator in case of new braking actions, and
after determining that the air pressure measured at step a) is between the first and the second threshold values, then using the pneumatic brake actuator and the electric brake actuator together in case of new braking actions.

2. The method according to claim 1 , wherein steps c) and d) include a sub-step a) that comprises measuring a state of charge of a vehicle battery that is normally used to power the electric brake actuator according to step c) or d).

3. The method according to claim 2 , wherein steps c) and d) include a sub-step β) posterior to step a), that comprises, after determining that the state of charge of the vehicle battery is lower than a predetermined value, activating a backup battery to power the electric brake actuator according to step c) or d).

4. The method according to claim 3 , wherein following the sub-step β) performing a predetermined number of new braking actions before a stopping rule of the vehicle is activated or a given distance is travelled by the vehicle before a stopping rule of the vehicle is activated.

5. The method according to claim 1 , wherein the method further comprises a step e) that consists, after determining that the air pressure measured at step a) is less than a third threshold value, the third threshold value being lower than the second threshold value, and after determining that the compressor is unable to build up the air pressure of the air tank, using only the electric brake actuator in case of new braking actions and activating a stopping rule of the vehicle after the performance of a predetermined number of new braking actions or after the vehicle has traveled a given distance since the braking system has been operated in the degraded mode or since the air pressure has been detected as being less than the third threshold value.

6. The method according to claim 1 , wherein a predetermined number of new braking actions is performed at steps c) and/or d) before a stopping rule of the vehicle is activated.

7. The method according to claim 6 , wherein the predetermined number of new braking actions allowable at step c) is greater than that at step d).

8. The method according to claim 1 , wherein a stopping rule of the vehicle is activated at steps c) and/or d) after the vehicle has traveled a given distance since the braking system has been operated in the degraded mode.

9. The method according to claim 8 , wherein the stopping rule of the vehicle consists in automatically immobilizing the vehicle when safe standstill conditions of the vehicle are detected.

10. The method according to claim 9 , wherein safe standstill conditions of the vehicle are detected when a speed of the vehicle falls below a certain value and/or when park brake activation is detected.

11. The method according to claim 1 , wherein the first threshold value is lower than or equal to a cut-in pressure of the air tank at which the air tank pressure is normally built up by the compressor.

12. The method according to claim 1 , wherein warning signals are sent to the driver of the vehicle at steps c) and d).

13. A braking system of a vehicle, the braking system comprising
at least a pair of coupled brake actuators that includes a pneumatic brake actuator supplied with a compressed air from an air tank that is pressured by a compressor, and an electric brake actuator,
means for automatically measuring the pressure of the air tank,
means to compare the measured pressure to a first threshold value and to a second threshold value and to assess whether the compressor

is able to build up the air pressure of the air tank, these means being adapted to:
i. after determining that the measured pressure is less than the first threshold value and after determining that the compressor is unable to build up the air pressure of the air tank, operate the braking system in a degraded mode wherein at least the electric brake actuator is used in case of new braking actions, and
ii. after determining that the measured pressure is less than the second threshold value, the second threshold value being lower than the first threshold value, and after determining that the compressor is unable to build up the air pressure of the air tank, use only the electric brake actuator in case of new braking actions, and
after determining that the air pressure measured at step a) is between the first and the second threshold values, use the pneumatic brake actuator and the electric brake actuator together in case of new braking actions.

14. A vehicle equipped with a braking system according to claim 13 .

Assignees

• Volvo Truck Corp

Inventors

• Farres Lionel
• Carle Jean Sebastien

Classifications

• B60T17/221

  Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems (hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M) · CPC title

• B60T13/683

  in pneumatic systems or parts thereof (in vacuum systems B60T13/72) · CPC title

• B60T13/662 Primary

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

• B60T17/02

  Arrangements of pumps or compressors, or control devices therefor · CPC title

• B60T17/22

  Devices for monitoring or checking brake systems; Signal devices · CPC title