Pressure modulator control

• US 20090115247A1
• Filed: 04/20/2006
• Published: 05/07/2009
• Est. Priority Date: 04/21/2005
• Status: Active Grant

• Current Assignee: IPGATE AG
• Original Assignee: Wolfram Gerber
• Inventors: Leiber, Thomas, Leiber, Heinz
• Granted Patent: US 8,540,324 B2
• Time in Patent Office: Days
• US Class Current: 303/154
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• 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 8/5006 Pressure reapplication by pulsing of valves B60T8/5012, B60T8/5018, B60T8/505, B60T8/5056 take precedence
• CPC Class Codes: B60T 8/5075 Pressure release by pulsing of valves B60T8/5081, B60T8/5087 take precedence

Abstract

The invention relates to a brake system which comprises an actuating device (26), especially a brake pedal (30), and a control/regulation device (22). Said control/regulation device (22) controls at least one electromotive drive device (7a, 7b, 8) in response to the movement and/or position of the actuating device (26). The drive device adjusts a piston (1, 1a, 1b) of a piston/cylinder system via a non-hydraulic transmission device, thereby adjusting a pressure in the working compartment (4′, 4′a, 4b′) of the cylinder. Said working compartment is connected to a wheel brake (15, 17) via a pressure conduit (13, 13a). A valve (14, 14a, 15, 15a, 14′, 14a′) is interposed between the brake cylinder of the wheel brake and the working compartment of the piston/cylinder system. The control/regulation device opens the valve for pressure suppression or pressure build-up in the brake cylinder and closes it in order to maintain the pressure in the brake cylinder.

Claims

1. Brake system comprising:

an actuating device, in particular a brake pedal, and a control and regulating device, the control and regulating device controlling at least one electromotive drive device using the movement and/or position of the actuating device, the drive device adjusting a piston of a piston-cylinder system via a non-hydraulic gearing device, so a pressure is adjusted in the working chamber of the cylinder, the working chamber being connected to a wheel brake by a pressure line, characterized in that a valve is arranged between the brake cylinder of the wheel brake and the working chamber of the piston-cylinder system, the control and regulating device opening the valve for pressure reduction and pressure build-up in the brake cylinder and closing the valve to maintain the pressure in the brake cylinder.

2. The brake system according to claim 1, wherein the drive device comprises an electromotive or electromechanical drive for adjusting the piston of the piston-cylinder system.

3. The brake system according to claim 1, wherein the drive device drives a piston which, together with a hydraulically coupled further piston, is arranged in a cylinder.

4. The brake system according to claim 3, wherein the brake system comprises a pressure transducer or pressure sensor for detecting the pressure in one of two brake circuits or their pressure lines, in particular in the primary brake circuit.

5. The brake system according to claim 4, wherein the controller uses the pressure transducer to adjust the brake pressures for both brake circuits.

6. The brake system according to claim 1, wherein the brake system comprises two piston-cylinder systems arranged parallel to each other, a drive device which adjusts the respectively associated piston being associated with each piston.

7. The brake system according to claim 1, wherein a valve, in particular a 2/2-way valve, is arranged between each wheel brake and the working chamber of the piston-cylinder system.

8. The brake system according to claim 1, wherein the hydraulic lines connecting the working chamber of the piston-cylinder system to the brake cylinder have a negligible flow resistance.

9. The brake system according to claim 8, wherein the valve has such a large flow cross-section that the valve does not have a throttling function, the valve being a 2/2-sliding valve in particular.

10. The brake system according to claim 8, wherein the valve is a pressure-compensated 2/2 way valve.

11. The brake system according to claim 1, wherein in the case of failure, the actuating device adjusts the at least one piston of the at least one piston-cylinder system directly or via a gearing.

12. The brake system according to claim 1, wherein the pressure in the working chamber of the piston-cylinder system and/or the brake cylinders of the wheel brakes is determined by means of sensors.

13. The brake system according to claim 1, wherein at least sections of the hydraulic lines connecting the wheel brakes to the piston-cylinder system can be heated by means of heating devices, in particular electrical heating elements.

14. The brake system according to claim 1, wherein the control and regulating device comprises a knowledge base, in particular in the form of performance data, which is constructively adapted in particular.

15. The brake system according to claim 1, wherein each brake circuit comprises a pressure modulating piston which is driven by a separate drive, it being possible to mechanically connect only one pressure modulating piston to the brake pedal.

16. The brake system according to claim 15, wherein the drives and pressure modulating pistons are arranged parallel to each other.

17. The brake system according to claim 1, wherein the pressure in the brake line can be determined by means of a pressure transducer or pressure sensor upstream of each solenoid valve of each brake circuit respectively.

18. A method for adjusting a pressure in at least one brake cylinder of a brake system according to claim 1 wherein at the same time or successively, the pressure in one or more brake cylinder(s) can be adjusted by means of the at least one piston-cylinder system and the valves associated with the wheel brakes.

19. The method according to claim 18, wherein the speed of change of the pressure build-up and/or pressure reduction in the wheel brakes is adjusted by means of the piston-cylinder system as a function of the driving state or the brake regulation of the vehicle or the respective wheel to be decelerated.

20. The method according to claim 18, wherein the speed of change of the pressure build-up and/or pressure reduction in a wheel brake changes during a control cycle.

21. The method according to claim 20, wherein the speed of change of the pressure build-up and/or pressure reduction during the time in which a valve of wheel brake is open is changed, in particular is high at the start and is reduced toward the end of the pressure reduction or build-up phase.

22. The method according to claim 1, wherein the control and regulating device determines the required pressure build-up, pressure reduction, pressure maintenance phases and/or optimum slip for the respective wheel or all decelerated vehicle wheels at least from the respective wheel speed, vehicle acceleration and the pressure in the respective brake cylinder of the wheel brake.

23. The method according to claim 1, wherein during the pressure build-up or pressure reduction for a first wheel brake, the control and regulating device opens the valve associated with the wheel brake and immediately after adjusting the pressure determined by the regulator for the first brake, closes the valve associated with the first wheel brake and by opening the valve for the second wheel brake adjusts the required pressure for the second wheel brake by means of the piston-cylinder system.

24. The method according to claim 23, wherein the required pressure reduction or pressure build-up for the wheel to be adjusted next is calculated in particular using the measured wheel acceleration and the moment of inertia of the wheel, in particular from the performance data.

25. The method according to claim 23, wherein the pressure reduction or pressure build-up to be newly adjusted for the second wheel brake is calculated during adjustment of the pressure for the first wheel brake.

26. The method according to claim 18, wherein the pressure is reduced in the case of two wheel brakes by opening the respectively associated valves at the same time, in particular if approximately the same pressure level prevails in the brake cylinders of the two wheel brakes at the start or in the first control cycle of a braking operation.

27. The method according to claim 26, wherein the tendency is for the valve for a first wheel to be closed rather than the valve of the second wheel.

28. The method according to claim 18, wherein the control and regulating device has a memory in which the pressure to be adjusted at the instant the associated valve of a wheel brake is closed, and/or the pressure signal, for example motor current or piston position, is stored.

29. The method according to claim 18, wherein during regulation by means of the piston-cylinder system an admission pressure is adjusted which is approx. 10 to 3.0%, in particular 20%, above the pressure to be adjusted.

30. The method according to claim 18, wherein after attaining the pressure buildup, the motor or piston is held in its position for a short time to ensure that the last-opened solenoid valve is completely closed.

31. The method according to claim 18, wherein the response time WA of the drive device is short to attain a large pressure reduction speed (dp_ab/dt) and/or pressure build-up speed (dp_au/dt), in particular in such a way that the speed of the change in pressure is greater than 1,500 bar per second.

32. The method according to claim 18, wherein the pressure reduction speed (dp_ab/dt) is selected or adjusted so as to be very high if a plurality of wheels are simultaneously intended for pressure reduction by the regulator.

33. The method according to claim 18, wherein the regulator calculates the optimum pressure to achieve the optimum slip for the decelerated wheel, and the pressure for the associated wheel brake is built up to a pressure which is slightly lower, in particular 1 to 20%, preferably 5 to 10%, lower than the calculated optimum pressure, in such a way that exceeding of the optimum slip again is avoided.

34. The method according to claim 33, wherein to achieve an optimum slip the pressure is built up in stages, a large pressure increase firstly taking place after the control cycle, followed by pressure maintenance phases alternating with pressure build-up phases each with low changes in pressure.

35. The method according to claim 34, wherein during a pressure maintenance phase for a first wheel, a pressure build-up phase for a second wheel is initiated or carried out by means of the same piston-cylinder system.

36. The method according to claim 18, wherein when activating the 2/2-way valves the regulating device takes account of their response times or idle times in such a way that the 2/2-way valves receive a command to open or close earlier by the duration of the response time of the valve, so the valve is actually opened or closed at the calculated instant.

37. The method according to claim 18, wherein the regulating device that controls the 2/2-way valves derives the response time of the valves from the reaction of the activated drive device or the piston adjustment travel that has taken place following corresponding activation and stores it in a memory for subsequent control.

38. The method according to claim 18, wherein to build-up or reduce the pressure in at least one wheel brake the piston of the piston-cylinder system is already adjusted and the associated valve(s) subsequently open(s)