Regulating an actual pressure of a motor vehicle clutch

Patent metadata

Field	Value
Publication number	US-10054174-B2
Application number	US-201415527030-A
Country	US
Kind code	B2
Filing date	Nov 19, 2014
Priority date	Nov 19, 2014
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

Actual pressure of a hydraulic clutch of a motor vehicle can be regulated by: a) providing a value for a desired pressure to be present in a clutch cylinder; b) filling the clutch cylinder with hydraulic fluid to achieve the desired pressure; c) wherein, if the desired pressure lies between 0 and 7 bar, the actual pressure in the clutch cylinder is adjusted by regulating a rotational speed of the pump of the electric motor, and if the desired pressure is greater than 7 bar, the actual pressure in the clutch cylinder is adjusted by regulating a motor current of the electric motor; d) regulating the actual pressure until the desired pressure is achieved.

First claim

The invention claimed is:

1. A method for regulating an actual pressure of a clutch of a motor vehicle, the clutch having a plurality of clutch linings and a clutch spring, and being connected to a hydraulic pressure system that has at least one pump driven by an electric motor, a clutch cylinder and a clutch piston, the hydraulic pressure system being arranged for delivering a hydraulic fluid into the clutch cylinder via the pump and for moving the clutch piston, so that the clutch linings are brought into contact with one another counter to a force of the clutch spring, the method comprising:
a) providing a value for a setpoint pressure which is to prevail in the clutch cylinder;
b) filling the clutch cylinder with the hydraulic fluid in order to reach the setpoint pressure;
c) determining that the setpoint pressure is one of less than or equal to 7 bar and greater than 7 bar, and, based on the determined set point pressure, selecting to set an actual pressure in the clutch cylinder by one of a regulation of rotational speed of the pump or the electric motor and a regulation of a motor current of the electric motor; and
d) regulating the actual pressure until the setpoint pressure is reached.

2. The method of claim 1 , wherein an air gap is overcome at a grip point of the clutch, and the clutch linings are in contact so that a further increase in the pressure in the pressure system would directly provide torque such that the value for the setpoint pressure would bring about providing torque by the clutch, and the clutch cylinder is filled with the hydraulic fluid, with the result that the grip point of the clutch is reached and exceeded, the method further comprising, if the setpoint pressure is between 1.5 and 7 bar, setting the actual pressure in the clutch cylinder by regulating the rotational speed of the pump or the electric motor.

3. The method of claim 1 , further comprising operating the pump or the electric motor as follows after an ignition of the motor vehicle is switched off during a follow-up time in phases i and ii as follows:
i) first at a constant rotational speed, and subsequently
ii) the electric motor being operated with a constant motor current,
in each case the values of the further parameters which occur of motor current and rotational speed being determined during the phases i and ii, and said values being taken into consideration for determining that the setpoint pressure is one of less than or equal to 7 bar and greater than 7 bar.

4. A motor vehicle having a drive unit, a transmission and at least one clutch, the clutch having a plurality of clutch linings and a clutch spring, and being connected to a hydraulic pressure system which has at least one pump that is driven by way of an electric motor, a clutch cylinder and a clutch piston, the hydraulic pressure system being arranged for delivering a hydraulic fluid into the clutch cylinder via the pump and for moving the clutch piston, so that the clutch linings are brought into contact with one another counter to a force of the clutch spring, a controller being provided and configured for:
a) providing a value for a setpoint pressure which is to prevail in the clutch cylinder;
b) filling the clutch cylinder with the hydraulic fluid in order to reach the setpoint pressure;
c) determining that the setpoint pressure is one of less than or equal to 7 bar and greater than 7 bar, and, based on the determined set point pressure, selecting to set an actual pressure in the clutch cylinder by one of a regulation of rotational speed of the pump or the electric motor and a regulation of a motor current of the electric motor; and
d) regulating the actual pressure until the setpoint pressure is reached.

5. The motor vehicle of claim 4 , wherein an air gap is overcome at a grip point of the clutch, and the clutch linings are in contact so that a further increase in the pressure in the pressure system would directly provide torque such that the value for the setpoint pressure would bring about providing torque by the clutch, and the clutch cylinder is filled with the hydraulic fluid, with the result that the grip point of the clutch is reached and exceeded, the controller further configured for, if the setpoint pressure is between 1.5 and 7 bar, setting the actual pressure in the clutch cylinder by regulating the rotational speed of the pump or the electric motor.

6. The motor vehicle of claim 1 , the controller further configured for operating the pump or the electric motor as follows after an ignition of the motor vehicle is switched off during a follow-up time in phases i and ii as follows:
i) first at a constant rotational speed, and subsequently
ii) the electric motor being operated with a constant motor current,
in each case the values of the further parameters which occur of motor current and rotational speed being determined during the phases i and ii, and said values being taken into consideration for determining that the setpoint pressure is one of less than or equal to 7 bar and greater than 7 bar.

Assignees

• Gkn Automotive Ltd

Inventors

• Langhanki Andreas
• Phan Khac Anh

Classifications

• F16D2500/1026

  Hydraulic · CPC title

• F16D25/0638

  with more than two discs, e.g. multiple lamellae · CPC title

• F16D2048/0233

  by rotary pump actuation · CPC title

• F16D48/02

  Control by fluid pressure · CPC title

• F16D2500/3024

  Pressure · CPC title