Method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle

Patent metadata

Field	Value
Publication number	US-9803703-B2
Application number	US-201514838838-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Sep 15, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle, the hybrid disconnect clutch separating or connecting an internal combustion engine and an electrical motor, including: delivering, to drive wheels of the hybrid vehicle, a torque output by the internal combustion engine and the electrical motor; determining the co-efficient of friction while the disconnect clutch is in a slipping state; operating the disconnect clutch in first and second operating modes, the first mode including an open state of the disconnect clutch and the second mode including a closed state of the disconnect clutch; and increasing the co-efficient of friction for more rapid adjustment of the slipping state only in the transition from the closed state to the opened state.

First claim

What is claimed is:

1. A method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle, the hybrid disconnect clutch separating or connecting an internal combustion engine and an electrical motor, comprising:
delivering, to drive wheels of the hybrid vehicle, a torque output by the internal combustion engine and the electrical motor;
determining the co-efficient of friction while the disconnect clutch is in a middle slipping state;
operating the disconnect clutch in first and second operating modes, the first mode including a fully opened state of the disconnect clutch and the second mode including a fully closed state of the disconnect clutch; and,
increasing the co-efficient of friction for rapid adjustment of the middle slipping state only in a transition from the fully closed state to the fully opened state.

2. The method according to claim 1 , further comprising:
reducing an over-pressing of the disconnect clutch via a relief process of a hydrostatic clutch actuator; and,
adjusting the middle slipping state of the disconnect clutch.

3. The method according to claim 1 , further comprising:
performing a rapid adaptation of the co-efficient of friction in order to shorten the middle slipping state of the disconnect clutch.

4. The method according to claim 1 , further comprising:
increasing the co-efficient of friction by a predefined amount at the transition from the fully closed state to the fully opened state.

5. The method according to claim 1 , further comprising:
comparing an actual co-efficient of friction variation with a threshold value for co-efficient of friction variation; and,
adjusting the actual co-efficient of friction for a deviation of the actual co-efficient of friction variation from the threshold value for co-efficient of friction variation.

6. The method according to claim 5 , further comprising:
increasing the actual co-efficient of friction variation when it falls below the threshold value for co-efficient of friction variation.

7. The method according to claim 5 , further comprising:
when the actual co-efficient of friction variation exceeds the threshold value for co-efficient of friction variation:
reducing an amount of variation; and,
adjusting the rapid adaptation of the co-efficient of friction accordingly.

8. The method according to claim 1 , further comprising:
increasing the co-efficient of friction by a predefined constant amount at the transition from the fully closed state to the fully opened state.

9. A method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle, the hybrid disconnect clutch separating or connecting an internal combustion engine and an electrical motor, comprising:
delivering, to drive wheels of the hybrid vehicle:
a torque output by the internal combustion engine; or,
a torque output by the electrical motor;

determining the co-efficient of friction while the disconnect clutch is in a middle slipping state;
operating the disconnect clutch in first and second operating modes, the first mode including a fully opened state of the disconnect clutch and the second mode including a fully closed state of the disconnect clutch; and,
increasing the co-efficient of friction for rapid adjustment of the slipping state only in a transition from the fully closed state to the fully opened state.

Assignees

• Schaeffler Technologies Ag

Inventors

• Hodrus Erhard

Classifications

• Y10S903/946

  Characterized by control of driveline clutch · CPC title

• F16D2500/1026

  Hydraulic · CPC title

• F16D2500/1066

  Hybrid · CPC title

• F16D2500/70426

  Clutch slip · CPC title

• F16D48/06 Primary

  Control by electric or electronic means, e.g. of fluid pressure · CPC title