METHOD FOR ACTUATING A MECHANISM IN A BRAKE BOOSTER UNIT OF A BRAKING SYSTEM AND BRAKING SYSTEM

Abstract

A method for actuating a mechanism in a brake booster unit. The method includes: ascertaining, using a control unit of a vehicle system, whether a driver's braking request has ended or whether there is no driver's braking request; detecting, using the control unit, an operational disruption of the brake booster unit; detecting, using the control unit, an operational disruption of a pressure controller, which is connected to the brake booster unit and configured to generate a braking pressure and/or a resetting pressure at a master brake cylinder unit of the brake booster unit; generating, using the vehicle system, a predetermined minimum pressure in the master brake cylinder unit and thereby resetting the mechanism and, by the mechanism, resetting a master brake cylinder into a neutral position.

Claims

1-10. (canceled)

11. A method for actuating a mechanism in a brake booster unit in a braking system, comprising the following steps: ascertaining, using a control unit of a vehicle system, whether a driver's braking request has ended after a preceding braking operation by the brake booster unit or whether there is no driver's braking request at the brake booster unit after the preceding braking operation by the brake booster unit; detecting, using the control unit, an operational disruption of the brake booster unit; detecting, using the control unit, an operational disruption of a pressure controller, which is connected or comprised by the brake booster unit, and is configured to generate a braking pressure and/or a resetting pressure at a master brake cylinder unit of the brake booster unit; generating, using the vehicle system, a predetermined minimum pressure in the master brake cylinder unit and thereby resetting the mechanism and, by the mechanism, resetting a master brake cylinder to a neutral position with reduced or no braking effect on a brake element: (i) when the driver's braking request has ended, or (ii) when there is no longer a driver's braking request; wherein the generating of minimum pressure is controlled by the control unit of the vehicle system.

12. The method according to claim 11, wherein the operational disruption of the brake booster unit relates to a resetting of the mechanism to the neutral position using the brake booster unit.

13. The method according to claim 11, where, using the vehicle system for the resetting, a predetermined volume of hydraulic fluid is fed from a hydraulic fluid storage chamber into the master brake cylinder unit, thereby generating the minimum pressure.

14. The method according to claim 13, wherein, before the resetting, the control unit ascertains a present volume of the hydraulic fluid in the storage chamber and compares the present volume to a predetermined operating quantity, and, when the present volume is less than the predetermined operating quantity, an additional volume is sucked by a pump via sealing lips of a piston of the master brake cylinder from a prechamber of the master brake cylinder into the storage chamber to achieve the minimum pressure and is then pumped out of the storage chamber into a pressure region of the master brake cylinder.

15. The method according to claim 14, wherein after the additional volume has been at least partially pumped into the pressure region, the step is repeated at least once, whereupon, before the resetting, the volume of hydraulic fluid present in the storage chamber is ascertained and compared with a predetermined operating quantity, and, when the volume present is less than the predetermined operating quantity, an additional volume is sucked by the pump via sealing lips from a prechamber of the master brake cylinder into the storage chamber in order to achieve the minimum pressure and is then pumped from the storage chamber into the pressure region of the master brake cylinder.

16. The method according to claim 11, wherein the control unit detects a presence of the driver's braking request via a pedal position and/or by ascertaining of a vehicle speed and/or via a driver interface.

17. The method according to claim 11, wherein the control unit is a control unit of a vehicle stability system.

18. The method according to claim 11, wherein the minimum pressure is sufficient to open a snifting bore when resetting the master brake cylinder.

19. A braking system, comprising: a brake booster unit; and a control unit of a vehicle system; wherein the brake booster unit is connected to the control unit and can be connected to a pressure controller or comprises a pressure controller, and wherein the control unit is configured to: ascertain, using the control unit, whether a driver's braking request has ended after a preceding braking operation by the brake booster unit or whether there is no driver's braking request at the brake booster unit after a preceding braking operation by the brake booster unit; to detect whether an operational disruption of the brake booster unit is present, detect whether there is an operational disruption of the pressure controller, wherein the pressure controller is connected to or comprised by the brake booster unit and is configured to generate a braking pressure and/or a resetting pressure at a master brake cylinder unit of the brake booster unit, and generate, using the vehicle system, a predetermined minimum pressure in the master brake cylinder unit and thereby to reset a mechanism and thereby reset a master brake cylinder into a neutral position with reduced or no braking effect on a brake element when the driver's braking request has ended or when there is no longer a driver's braking request, wherein the generating of the minimum pressure can be controlled by the control unit of the vehicle system.

20. The braking system according to claim 19, wherein the control unit includes a control unit of a vehicle stability system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention is explained in greater detail below with reference to the embodiment examples indicated in the schematic figures.

[0052] FIG. 1 shows a schematic illustration of a braking system according to an embodiment example of the present invention.

[0053] FIG. 2 shows a block diagram of process steps of the method for actuating a mechanism in a brake booster unit in a braking system according to an embodiment example of the present invention.

[0054] In the figures, identical reference signs denote identical or functionally identical elements.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0055] FIG. 1 shows a schematic illustration of a braking system according to an embodiment example of the present invention.

[0056] Braking system 1 is shown having brake booster unit 10 and a control unit SE of a vehicle system ESP, wherein the brake booster unit 10 is connected to the control unit SE and can be connected to a pressure controller or comprises a pressure controller (this can mean the brake booster unit 10 or the ESP or another pressure controller), wherein the control unit SE is designed to ascertain, by way of the control unit SE, whether a driver's braking request has ended after a preceding braking operation by the brake booster unit 10 or whether there is no driver's braking request at the brake booster unit 10 after a preceding braking operation by the brake booster unit 10; to detect whether there is an operational disruption of the brake booster unit 10; to detect whether there is an operational disruption of a pressure controller, wherein the pressure controller is connected to the brake booster unit and is designed to generate a braking pressure and/or a resetting pressure at a master brake cylinder unit HZE of the brake booster unit 10; and to generate, by way of the vehicle system ESP, a predetermined minimum pressure in the master brake cylinder unit HZE and thereby to effect a resetting of the mechanism and thereby a resetting of a master brake cylinder into a neutral position with reduced or no braking effect on a brake element when the driver's braking request has ended or when there is no longer a driver's braking request, wherein the generating of the minimum pressure can be controlled by the control unit of the vehicle system.

[0057] The ESP a detects the failure of the pressure actuator b. This can happen, for example, via conventional mechanisms such as network monitoring g or an electrical signal g. The ESP a can check whether a braking request is present. This is possible via a signal interface, for example with the control unit SE. If a braking request is present, the ESP can have the task of generating pressure in the wheels as a substitute regulator for the brake booster. The function can become active if there is no braking request, but it cannot be ruled out that there is still residual pressure in the system. The ESP function can be activated and aims to pump volume towards the TMC (HZE, f) in order to generate pressure against the TMC pistons if the snifting bores have not yet been opened. If there is too little volume in the ESP, the latter by means of pump e first draws volume over the sealing lips of the TMC, which act like a check valve.

[0058] The HSV h is open for this purpose and the USV i is closed. The EVs j and AVs k are also open. The volume can be balanced using a model that knows the history of the measured pressure and of the pumps e and valve activities (h, i, j, k). The volume is temporarily stored in the storage chamber d. Once the storage chamber d is at least partially filled, the ESP begins to return volume in the direction of the TMC f. For this purpose, the HSV h and the EVs j are closed in order to convey the volume from the storage chamber towards the ESP. As long as the snifting bores are closed, pressure is generated which resets the pistons and the mechanism with motor behind them.

[0059] FIG. 2 shows a block diagram of method steps of the method for actuating a mechanism in a brake booster unit in a braking system according to an embodiment example of the present invention.

[0060] The method for actuating a mechanism in a brake booster unit of a braking system comprises ascertaining S1 by means of a control unit of a vehicle system whether a driver's braking request has ended after a preceding braking operation by the brake booster unit or whether there is no driver's braking request at the brake booster unit after a preceding braking operation by the brake booster unit; detecting S2, by way of the control unit, an operational disruption of the brake booster unit; detecting S3, by way of the control unit, an operational disruption of a pressure controller, which pressure controller is connected to the brake booster unit and is designed to generate a braking pressure and/or a resetting pressure at a master brake cylinder unit of the brake booster unit; generating S4, by way of the vehicle system, a predetermined minimum pressure in the master brake cylinder unit and thereby resetting the mechanism and by said mechanism resetting a master brake cylinder to a neutral position with reduced or no braking effect on a brake element when the driver's braking request has ended or when there is no longer a driver's braking request, wherein the generating of the minimum pressure is controlled by the control unit of the vehicle system.

[0061] Although the present invention has been completely described hereinabove with reference to the preferential embodiment example, it is not limited thereto and can be modified in a variety of ways.