Vehicle braking system with active hydraulic brake force assistance and control method for the same

• US 20050173978A1
• Filed: 04/28/2003
• Published: 08/11/2005
• Est. Priority Date: 04/27/2002
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Fennel, Helmut, Sticher, Thomas
• Granted Patent: US 7,537,294 B2
• Time in Patent Office: Days
• US Class Current: 303/114.300
• CPC Class Codes: B60T 13/148 Arrangements for pressure supply
• CPC Class Codes: B60T 13/161 Systems with master cylinder
• CPC Class Codes: B60T 2201/12 Pre-actuation of braking systems without significant braking effect; Optimizing brake performance by reduction of play between brake pads and brake disc
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 8/3655 Continuously controlled electromagnetic valves
• CPC Class Codes: B60T 8/442 the booster being a fluid return pump, e.g. in combination with a brake pedal force booster
• CPC Class Codes: B60T 8/4872 pump-back systems

Abstract

In a method of controlling a hydraulic vehicle brake system with active hydraulic brake force boosting, wherein the driver can introduce brake pressure into a master brake cylinder by means of an actuating device, preferably a brake pedal, wherein the pressure introduced by the driver is boosted by means of an active hydraulic pressure increasing unit, in particular a hydraulic pump, a braking request or a suspected braking request of the driver is determined and, when a braking request or a suspected braking request of the driver is detected, a separating valve that is arranged in a line connecting the master brake cylinder and the hydraulic pressure increasing unit is opened or remains open and the pressure increasing unit is actuated for pressure generation purposes.

Claims

1-12. -12. (canceled)

13. A method of controlling a hydraulic vehicle brake system with active hydraulic brake force boosting, wherein the driver can introduce brake pressure into a master brake cylinder by means of an actuating device, wherein the pressure introduced by the driver is boosted by means of an active hydraulic pressure increasing unit,

and wherein a braking request or a suspected braking request of the driver is determined and, when a braking request or a suspected braking request of the driver is detected, a separating valve that is arranged in a line interconnecting the master brake cylinder and the hydraulic pressure increasing unit is opened or remains open and the pressure increasing unit is actuated for pressure generation purposes.

14. Method as claimed in claim 13,

wherein after the actuation of the pressure increasing unit, dynamic pressure is produced upstream of the separating valve and at least clearances in the system are overcome and brake linings are applied to brake drums or brake discs, respectively.

15. Method as claimed in claim 13,

wherein the separating valve remains open until it is found out that the driver has initiated the braking operation.

16. Method as claimed in claim 13,

the method further comprising the separating valve remains open until it is found out that the driver has initiated the braking operation,

wherein the initiation of the braking operation by the driver is detected when the driver touches the brake pedal, a defined force is applied to the brake pedal, or it is detected that the brake pedal covers a defined distance from its inactive or initial position in the actuating direction.

17. Method as claimed in claim 13,

wherein the separating valve remains open for a predetermined time period.

18. Method as claimed in claim 13,

wherein the time in which the separating valve is opened is variably adjusted in accordance with the brake pedal travel, the brake pedal speed, the brake pedal acceleration, or the pressure gradient at the tandem master cylinder.

19. Method as claimed in claim 13,

wherein the braking request of the driver is determined on the basis of a movement of the driver'"'"'s foot before the braking operation.

20. Method as claimed in claim 13,

the method further comprising the braking request of the driver is determined on the basis of a movement of the driver'"'"'s foot before the braking operation,

wherein the braking request of the driver is determined on the basis of an accelerator pedal movement such as the accelerator pedal travel, accelerator pedal return speed, or accelerator pedal return acceleration before the braking operation.

21. Method as claimed in claim 13,

the method further comprising the braking request of the driver is determined on the basis of a movement of the driver'"'"'s foot before the braking operation,

wherein the braking request of the driver is determined on the basis of the movement of the driver'"'"'s foot when changing from the accelerator pedal to the brake pedal.

22. Method as claimed in claim 13,

wherein the separating valve is a hydraulic valve.

23. Hydraulic brake system for vehicles including a master brake cylinder operable by means of an actuating device, and at least one pump whose pressure can be applied to at least one wheel brake of the vehicle for the purpose of generation of hydraulic brake force boosting, which pump on the inlet side (suction side) is connectable to the master brake cylinder by way of at least one hydraulic conduit into which a change-over valve is inserted, while the pump on the outlet side (pressure side) is connectable to at least one wheel brake of the vehicle by way of at least one hydraulic conduit and is connectable to the master brake cylinder by way of at least one hydraulic conduit into which a separating valve is inserted,

wherein a detection means is provided in order to detect a braking request of the driver or determine a suspected braking request of the driver, and wherein an electronic evaluating unit for actuating the pump and the separating valve is provided which actuates the separating valve in order to open the connection to the pump and actuates the pump in order to generate hydraulic pressure when the braking request of the driver is detected or a suspected braking request of the driver is determined.

24. Hydraulic brake system as claimed in claim 23,

wherein the pressure side of the pump is connected to the wheel brake by way of a hydraulic conduit into which an inlet valve is inserted, the wheel brake of the vehicle is connected to the master brake cylinder by way of a hydraulic conduit into which an outlet valve is inserted, and wherein a pressure sensor is associated with the master brake cylinder and a wheel speed sensor is associated with the vehicle wheels.