Method and device for regulating a brake system

Patent metadata

Field	Value
Publication number	US-10017165-B2
Application number	US-201414912672-A
Country	US
Kind code	B2
Filing date	Aug 8, 2014
Priority date	Aug 19, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A method for regulating motor vehicle electrohydraulic brake systems having a pressure supply apparatus actuated by a control unit and hydraulically connected to wheel brakes via a pressure regulating valve. The pressure supply apparatus includes a cylinder-piston assembly operated by an electromechanical actuator. A set point pressure value is determined for each wheel brake. The cylinder-piston assembly is actuated to a predetermined pilot pressure in the hydraulic pressure chamber. A pilot pressure actual value and an actuator speed actual value are obtained. A pilot pressure set point value, the pilot pressure set point value and the pilot pressure actual value are fed as input variables to a regulator which outputs an actuator speed set point value. The actuator speed and actual set point values are fed as inputs to the speed regulator. The actuator speed set point value is modified as a function of the number of brakes.

First claim

The invention claimed is:

1. A method for regulating an electrohydraulic brake system for motor vehicles, which can be actuated in a “brake-by-wire” operating mode, comprising:
providing a pressure supply apparatus which can be actuated by an electronic open-loop and closed-loop control unit and which is or can be connected to hydraulically activated wheel brakes and by which the wheel brakes can be activated hydraulically via at least one pressure regulating valve,
providing the pressure supply apparatus having a cylinder-piston assembly having a hydraulic pressure chamber, and pressure piston of which can be slid relative to a position of rest by an electromechanical actuator,
determining a set point pressure value for each wheel brake,
actuating the cylinder-piston assembly in such a way that a predetermined pilot pressure, which is determined from the set point pressure values, is set in the hydraulic pressure chamber by sliding the piston,
obtaining a pilot pressure actual value and an actuator speed actual value,
determining a pilot pressure set point value and feeding the pilot pressure set point value and the pilot pressure actual value as input variables to a regulator device, provided in a form having a pressure regulator and a speed regulator which is connected downstream of the pressure regulator, wherein the pressure regulator outputs an actuator speed set point value and feeding the actuator speed set point value and the actuator speed actual value as input variables to the speed regulator, and
modifying the actuator speed set point value which is fed to the speed regulator as a function of the number of the wheel brakes, the modifying comprises the multiplication of the set point value by a scaling factor (K), and the scaling factor (K) is based on the number of the wheel brakes which are connected to the hydraulic pressure chamber via the at least one pressure regulating valve, and
determining a relative volume as a sum of wheel brake relative volumes of the individual wheel brakes, and wherein calculating the respective wheel brake relative volume as quotient of a wheel brake volume of the respective wheel brake and the total volume of the brake system multiplied by the number 100 when the respective wheel brake is currently hydraulically connected and is otherwise zero, and wherein the scaling factor (K) is a function of the relative volume.

2. The method as claimed in claim 1 , wherein the scaling factor (K) depends linearly on the relative volume.

3. The method as claimed in claim 2 , further comprising the step of determining the scaling factor (K) according to
K setp =K min +(1− K min )* V rel,total /100,

wherein K min is a minimum value between 0 and 1, and V rel,total denotes the relative volume.

4. The method as claimed in claim 3 , wherein K min is between 0.1 and 0.4.

5. A method for regulating an electrohydraulic brake system for motor vehicles, which can be actuated in a “brake-by-wire” operating mode, comprising:
providing a pressure supply apparatus which can be actuated by an electronic open-loop and closed-loop control unit and which is or can be connected to hydraulically activated wheel brakes and by which the wheel brakes can be activated hydraulically via at least one pressure regulating valve,
providing the pressure supply apparatus having a cylinder-piston assembly having a hydraulic pressure chamber, and pressure piston of which can be slid relative to a position of rest by an electromechanical actuator,
determining a set point pressure value for each wheel brake,
actuating the cylinder-piston assembly in such a way that a predetermined pilot pressure, which is determined from the set point pressure values, is set in the hydraulic pressure chamber by sliding the piston,
obtaining a pilot pressure actual value and an actuator speed actual value,
determining a pilot pressure set point value and feeding the pilot pressure set point value and the pilot pressure actual value as input variables to a regulator device, provided in a form having a pressure regulator and a speed regulator which is connected downstream of the pressure regulator, wherein the pressure regulator outputs an actuator speed set point value and feeding the actuator speed set point value and the actuator speed actual value as input variables to the speed regulator,
modifying the actuator speed set point value which is fed to the speed regulator as a function of the number of the wheel brakes, the modifying comprises the multiplication of the set point value by a scaling factor (K), and the scaling factor (K) is based on the number of the wheel brakes which are connected to the hydraulic pressure chamber via the at least one pressure regulating valve, and
wherein the scaling factor (K) is not replaced immediately after a re-calculation but instead a previous scaling factor (K) is changed in the direction of a newly calculated scaling factor, wherein the maximum change in the scaling factor (K) depends on the difference between the previous scaling factor (K) and the newly calculated scaling factor.

6. The method as claimed in claim 1 further comprising wherein considering the state of a respective inlet valve or an actuator connection valve in order to determine the respective wheel brake relative volume.

7. The method as claimed in claim 1 to further comprising determining the scaling factor (K) at regular time intervals.

8. A device for regulating an electrohydraulic brake system comprising:
a control unit in communication with a pressure supply apparatus which can be actuated by an electronic open-loop and closed-loop control unit and which is or can be connected to hydraulically activated wheel brakes and by which the wheel brakes can be activated hydraulically via at least one pressure regulating valve, the pressure supply apparatus having a cylinder-piston assembly having a hydraulic pressure chamber, and pressure piston of which can be slid relative to a position of rest by an electromechanical actuator,
the control unit being configured to:
determine a set point pressure value for each wheel brake,
actuate the cylinder-piston assembly in such a way that a predetermined pilot pressure, which is determined from the set point pressure values, is set in the hydraulic pressure chamber by sliding the piston,
obtain a pilot pressure actual value and an actuator speed actual value,
determine a pilot pressure set point value and feeding the pilot pressure set point value and the pilot pressure actual value as input variables to a regulator device, provided in a form having a pressure regulator and a speed regulator which is connected downstream of the pressure regulator, wherein the pressure regulator outputs an actuator speed set point value and feeding the actuator speed set point value and the actuator speed actual value as input variables to the speed regulator,
modify the actuator speed set point value which is fed to the speed regulator as a function of the number of the wheel brakes, the modifying comprises the multiplication of the set point value by a scaling factor (K), and the scaling factor (K) is based on the number of the wheel brakes which are connected to the hydraulic pressure chamber via the at least one pressure regulating valve and portion of a total volume of the brake system,
determine a relative volume as a sum of wheel brake relative volumes of the individual wheel brakes, and wherein calculating the respective wheel brake relative volume as quotient of a wheel brake volume of the respective wheel brake and the total volume of the brake system multiplied by the number 100 when the respective wheel brake is currently hydraulically connected and is otherwise zero, and wherein the scaling factor (K

Assignees

• Continental Teves Ag & Co Ohg

Inventors

• Böhm Jürgen
• Roll Georg
• Besier Marco

Classifications

• B60T13/66

  Electrical control in fluid-pressure brake systems · CPC title

• B60T13/745

  acting on a hydraulic system, e.g. a master cylinder · CPC title

• B60T7/042 Primary

  by electrical means, e.g. using travel or force sensors · CPC title

• B60T13/662

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

• B60T8/172 Primary

  Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters {(B60T8/17551 takes precedence)} · CPC title