Electrohydraulic Motor Vehicle Brake System and Method for Operating the Same

• US 20150344014A1
• Filed: 11/28/2013
• Published: 12/03/2015
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Lucas Automotive GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Lucas Automotive GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Knechtges, Josef, Grieser-Schmitz, Stefan
• Granted Patent: US 9,616,870 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60T 2270/82 Brake-by-Wire, EHB
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/4077 Systems in which the booster is used as an auxiliary pressure source
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence
• CPC Class Codes: B60T 8/447 Reducing the boost of the power-assist booster means to reduce brake pressure

Abstract

The invention relates to a technique for operating an electrohydraulic motor vehicle brake system comprising a master cylinder, an electromechanical actuator for generating a hydraulic pressure at a plurality of wheel brakes and a set of electrically actuable valve arrangements. The set of valve arrangements comprises a first valve arrangement between the master cylinder and every wheel brake. The first valve arrangements can be controlled in the multiplex operation to generate, by means of the electromechanical actuator, the respective brake pressure intended for each of the wheel brakes. According to an aspect of this technique, the method comprises the steps of: generating a feedback current during the multiplex operation by operating an electric motor of the electromechanical actuator as a generator and supplying the feedback current to at least one electrical load.

Claims

1. A method for operating an electrohydraulic motor-vehicle brake system which has a master cylinder, an electromechanical actuator for generating a hydraulic pressure at a plurality of wheel brakes, and a set of electrically actuable valve arrangements, the set of valve arrangements each comprising a first valve arrangement between the master cylinder and each wheel brake in order to generate the respective braking pressure intended for each of the wheel brakes by means of the electromechanical actuator, comprising the steps:

generating a regenerative current by operating an electric motor of the electromechanical actuator as a generator; and

energising at least one electrical load with the regenerative current.

2. A method according to claim 1, wherein the first valve arrangements can be controlled in a multiplex operation with the regenerative current being generated during the multiplex operation by operating the electric motor as a generator.

3. A method according to claim 1, further comprising:

connecting an electrical load to the electric motor in order to fully or partially consume the regenerative current generated by the electric motor in generator mode.

4. A method according to claim 3, further comprising:

detecting a signal which indicates a regenerative current generated by the electric motor; and

comparing the signal to a reference signal indicating an upper current limit.

5. A method according to claim 4, further comprising:

connecting the electrical load to the electric motor when the signal exceeds the reference signal.

6. A method according to claim 1, wherein the at least one electrical load is part of the electrohydraulic motor-vehicle brake system.

7. A method according to claim 1, wherein the at least one electrical load is the electric motor.

8. A method according to claim 7, wherein a field current is generated by the regenerative current in the electric motor.

9. A method according to claim 1, wherein the at least one electrical load comprises at least one valve arrangement from the set of valve arrangements.

10. A method according to claim 9, wherein the at least one valve arrangement provided as an electrical load comprises at least one of the first valve arrangements.

11. A method according to claim 9, wherein the set of valve arrangements comprises at least one second valve arrangement which enables the additional connection of a hydraulic simulation device for a pedal reaction behaviour, and wherein the at least one valve arrangement provided as an electrical load comprises at least the second valve arrangement.

12. A method according to claim 9, wherein the at least one valve arrangement is energised by means of the regenerative current with a higher current than in normal mode.

13. A method according to claim 9, wherein the regenerative current is fed to the at least one valve arrangement via a pulse-width modulation.

14. A computer program product with a program code for performing the method according to claim 1 when the computer program product runs on at least one processor.

15. A motor-vehicle control or control system comprising the computer program product according to claim 14.

16. An electrohydraulic motor-vehicle brake system (100) comprising:

a master cylinder;

an electromechanical actuator for generating a hydraulic pressure at a plurality of wheel brakes; and

a set of electrically actuable valve arrangements each with a first valve arrangement between the master cylinder and each wheel brake in order to generate the respective braking pressure intended for each of the wheel brakes by the electromechanical actuator; and

a control device or control device system which is designed for

generating a regenerative current by operating an electric motor of the electromechanical actuator as a generator; and

energising at least one electrical load with the regenerative current.

17. An electrohydraulic motor-vehicle brake system according to claim 16, wherein the control device or control device system is designed to control the first valve arrangements in multiplex mode, with the regenerative current being generated during the multiplex operation by operating the electric motor as a generator.

18. An electrohydraulic motor-vehicle brake system according to claim 16, wherein the control device or control device system is designed:

to detect a signal which indicates a regenerative current generated by the electric motor; and

to compare the signal with a reference signal indicating an upper current limit.

19. An electrohydraulic motor-vehicle brake system according to claim 18, wherein the control device or control device system is designed:

to connect the electrical load to the electric motor when the signal exceeds the reference signal.

20. A brake system according to claim 16, wherein the electromechanical actuator acts on a piston received in the master cylinder.

21. A brake system according to claim 16, wherein the electromechanical actuator is designed to act on a piston which is guided in a cylinder provided in addition to the master cylinder, with the additional cylinder being fluidically coupleable or coupled to wheel brakes.