Electronically controllable pneumatic brake system in a utility vehicle and method for electronically controlling a pneumatic brake system in a utility vehicle

Patent metadata

Field	Value
Publication number	US-10501062-B2
Application number	US-201716319833-A
Country	US
Kind code	B2
Filing date	Jul 10, 2017
Priority date	Aug 31, 2016
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

An electronically controllable pneumatic brake system in a vehicle includes wheel brakes for braking respective wheels of the vehicle. Wheel brakes of at least one vehicle axle include spring-loaded cylinders for implementing a pneumatic parking brake in a parking brake braking circuit of the vehicle. The brake system further includes an electronically controllable monostable bypass valve, wherein the monostable bypass valve is disposed between a manually operated parking brake valve and the spring-loaded cylinders. The monostable bypass valve controls, in a first switching position, a bypass control pressure based on an actuation pressure produced by the parking brake valve to implement a manually specified parking brake force. The monostable bypass valve further controls, in a second switching position, a bypass control pressure depending on a venting pressure prevailing in a bypass vent connection to implement an electrically specified parking brake force.

First claim

The invention claimed is:

1. An electronically controllable pneumatic brake system in a vehicle, the brake system comprising:
wheel brakes for braking respective wheels of the vehicle, wherein wheel brakes of at least one vehicle axle include spring-loaded cylinders for implementing a pneumatic parking brake in a parking brake braking circuit of the vehicle,
an electronically controllable monostable bypass valve, wherein the monostable bypass valve is disposed between a manually operated parking brake valve and the spring-loaded cylinders such that the monostable bypass valve:
controls, in a first switching position, a bypass control pressure based on an actuation pressure produced by the parking brake valve to implement a manually specified parking brake force, wherein a maximum actuation pressure corresponds to a reservoir pressure of a reservoir pressure medium in a parking brake pressure medium reservoir supplying the parking brake braking circuit, and
controls, in a second switching position, a bypass control pressure depending on a venting pressure prevailing in a bypass vent connection to implement an electrically specified parking brake force,
wherein a parking brake braking pressure controlled at the spring-loaded cylinder can be set depending on the respective bypass control pressure, and
wherein the monostable bypass valve automatically changes over to the first switching position without electrical actuation.

2. The electronically controllable pneumatic brake system as claimed in claim 1 , further comprising, between the manually actuatable parking brake valve and the spring-loaded cylinders, a parking brake relay valve configured to produce an air volume-boosted relay valve pressure based on a parking brake control pressure such that the monostable bypass valve:
controls, in the first switching position, the actuating pressure produced by the parking brake valve as the bypass control pressure and passes the same as the parking brake control pressure to a pneumatic control input of the parking brake relay valve, or controls the air volume-boosted relay valve pressure produced because of the actuation pressure by the parking brake relay valve as the bypass control pressure and passes the same as the parking brake braking pressure to the spring-loaded cylinders to implement the manually specified parking brake force, and
controls, in a second switching position, the venting pressure prevailing in the bypass vent connection as the bypass control pressure and passes the same as the parking brake control pressure to the pneumatic control input of the parking brake relay valve to implement the electrically specified parking brake force.

3. The electronically controllable pneumatic brake system as claimed in claim 2 , wherein the monostable bypass valve is disposed between the parking brake valve and the pneumatic control input of the parking brake relay valve to output the actuation pressure as the parking brake control pressure in the first switching position and the venting pressure as the parking brake control pressure in the second switching position.

4. The electronically controllable pneumatic brake system, as claimed in claim 2 , wherein the monostable bypass valve is disposed between a pneumatic brake pressure output of the parking brake relay valve and the spring-loaded cylinders to output the relay valve pressure as the parking brake braking pressure in the first switching position and the venting pressure as the parking brake braking pressure in the second switching position.

5. The electronically controllable pneumatic brake system as claimed in claim 1 , wherein on detecting a long-term switch-off of the vehicle and an unactuated parking brake valve, a venting function can be carried out, wherein the parking brake pressure medium reservoir can be emptied by the venting function to hold the vehicle at a standstill for the long term, even without electrical actuation of the monostable bypass valve.

6. The electronically controllable pneumatic brake system as claimed in claim 5 , wherein the venting function can prevent the provision of reservoir pressure medium for the parking brake braking circuit with a reservoir pressure of greater than or equal to an opening pressure of the spring-loaded cylinders to apply the spring-loaded cylinders with the monostable bypass valve in the first switching position.

7. The electronically controllable pneumatic brake system as claimed in claim 5 , wherein a pressure medium reservoir filling device interacts with an engine of the vehicle such that filling the parking brake pressure medium reservoir is prevented once the engine is turned off, wherein at the same time the first and second switching positions of the monostable bypass valve can be set alternately with the engine turned off to reduce the reservoir pressure in the parking brake pressure medium reservoir by building up a parking brake braking pressure from the parking brake pressure medium reservoir in the first switching position and venting the parking brake braking circuit in the second switching position.

8. The electronically controllable pneumatic brake system, as claimed in claim 7 , wherein turning off the engine by means of a switch-off signal or by activation of an immobilizer can be detected.

9. The electronically controllable pneumatic brake system as claimed claim 1 , wherein the monostable bypass valve can be actuated electrically by means of a bypass signal specified by a parking brake control device,
wherein the monostable bypass valve changes into the first, de-energized switching position when there is no actuation by means of the bypass signal and changes into the second, energized switching position in the event of actuation by means of the bypass signal.

10. The electronically controllable pneumatic brake system as claimed in claim 9 , wherein the parking brake control device is embodied to specify the bypass signal such that the monostable bypass valve can be alternately changed over between the first switching position and the second switching position to implement graduated braking and to implement a cadence braking function by varying the parking brake braking pressure.

11. The electronically controllable pneumatic brake system as claimed in claim 10 , wherein the bypass signal can be specified by pulse width modulation.

12. The electronically controllable pneumatic brake system as claimed in claim 9 , wherein the bypass signal can be specified by the parking brake control device depending on a comfort function, for example a hill-holder function or a hill-starting aid, or depending on an automatic parking brake function or an auxiliary parking brake function or a redundancy function specified by an assistance control device.

13. The electronically controllable pneumatic brake system as claimed in claim 12 , wherein the redundancy function can be activated in the event of a failure or a defect during the electronic actuation of the axle modulators, wherein as a result the monostable bypass valve can be electrically actuated by means of the bypass signal specified by the parking brake control device for redundant electropneumatic braking of the vehicle by means of the pneumatic parking brake.

14. The electronically controllable pneumatic brake system as claimed in claim 9 , wherein the actuating pressure controlled by means of the parking brake valve can be produced depending on a manual parking brake force (fPBm) specified by manual actuation of the parking brake valve without actuation by the bypass signal.

15. The electronically controllable pneumatic brake system as claimed in claim 1 ,

Assignees

• Wabco Europe Bvba

Inventors

• Wulf Oliver

Classifications

• B60T13/662

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

• B60T2270/10

  ABS control systems · CPC title

• B60W10/184

  with wheel brakes · CPC title

• B60W10/188

  hydraulic brakes · CPC title

• B60T13/683 Primary

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