Method for ascertaining a clutch characteristic variable by means of an electric motor

Patent metadata

Field	Value
Publication number	US-11536328-B2
Application number	US-202217838574-A
Country	US
Kind code	B2
Filing date	Jun 13, 2022
Priority date	Oct 30, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A method ascertains a characteristic variable of a clutch installed into the powertrain of a vehicle for transmitting torque between a clutch input and a clutch output. A first electric motor is connected to the clutch input to introduce a first drive torque into the clutch. The torque is ascertained when the vehicle is at a standstill in that the clutch is first opened; the first electric motor is regulated at a first rotational speed; the clutch output is regulated at a second rotational speed; a counter torque which counteracts the transmission torque is applied to the clutch output; the clutch is then closed in order to assume a slipping state in which a specific differential rotational speed between the clutch input and the clutch output is present; the first drive torque is then ascertained; and the transmission torque is determined on the basis of the first drive torque.

First claim

What is claimed is:

1. A vehicle comprising:
an internal combustion engine having an output shaft;
a first electric motor driveably connected to the output shaft;
a second electric motor;
a clutch selectively coupling the output shaft to the second electric motor; and
a controller programmed to, while the vehicle is at a standstill:
regulate the first electric motor at a first rotational speed;
regulate the second electric motor at a second rotational speed;
close the clutch to assume a slipping state in which a specific differential rotational speed, formed from the first and second rotational speeds, is present between the clutch input and the clutch output; and
then, upon determining a first drive torque, determine a transmission torque based on the first drive torque.

2. The vehicle of claim 1 , wherein the second rotational speed is lower than the first rotational speed.

3. The vehicle of claim 2 , wherein the second rotational speed is equal to zero.

4. The vehicle of claim 1 , wherein the internal combustion engine is not generating power during the standstill but has a drag torque, the controller being further programmed to determine the transmission torque based on a difference between the first drive torque and the drag torque.

5. The vehicle of claim 4 , wherein the controller is further programmed to determine the drag torque when the clutch is still open by determining a first drive torque of the first electric motor rotating at a third rotational speed before closing the clutch and determining the drag torque as the first drive torque.

6. The vehicle of claim 1 , wherein the controller is further programmed to determine a coefficient of friction based on the transmission torque and the rotational speed difference.

7. The vehicle of claim 1 , wherein the clutch is a disconnect clutch.

8. A method, comprising, while a vehicle is at a standstill:
regulating a first electric motor at a first rotational speed, wherein the first electric motor is connected to a clutch input of a clutch;
regulating a second electric motor at a second rotational speed, wherein the second electric motor is connected to a clutch output of the clutch;
closing the clutch to assume a slipping state in which a specific differential rotational speed, formed from the first and second rotational speed, is present between the clutch input and the clutch output; and
then, upon determining a first drive torque, determining a transmission torque based on the first drive torque.

9. The method of claim 8 , wherein the second rotational speed is lower than the first rotational speed.

10. The method of claim 9 , wherein the second rotational speed is equal to zero.

11. The method of claim 8 , wherein an internal combustion engine is connected to the clutch input to effect a further drive torque.

12. The method of claim 11 , wherein the internal combustion engine is not generating power during the standstill but has a drag torque, wherein the transmission torque is determined based on a difference between the first drive torque and the drag torque.

13. The method of claim 12 , wherein the drag torque is determined when the clutch is still open by determining a first drive torque of the first electric motor rotating at a third rotational speed before closing the clutch and determining the drag torque as the first drive torque.

14. The method of claim 8 , further comprising determining a coefficient of friction based on the transmission torque and the rotational speed difference.

15. The method of claim 8 , wherein the clutch is a disconnect clutch.

16. A method, comprising:
regulating a first electric motor at a first rotational speed, wherein the first electric motor is connected to a clutch input of a clutch;
regulating a second electric motor at a second rotational speed, wherein the second electric motor is connected to a clutch output of the clutch;
applying a counter torque with the second electric motor;
closing the clutch to assume a slipping state in which a specific differential rotational speed, formed from the first and second rotational speed, is present between the clutch input and the clutch output; and
determining a coefficient of friction based on the counter torque and the differential rotational speed.

17. The method of claim 16 , wherein the second rotational speed is lower than the first rotational speed.

18. The method of claim 17 , wherein the second rotational speed is equal to zero.

19. The method of claim 16 , wherein the clutch is a disconnect clutch.

Assignees

• Schaeffler Technologies Ag

Inventors

• Enders Timo
• Mannsperger Ralf

Classifications

• F16D2500/1045

  Friction clutch · CPC title

• F16D2500/3111

  Standing still, i.e. signal detecting when the vehicle is standing still or bellow a certain limit speed · CPC title

• F16D2500/70434

  Input shaft torque · CPC title

• F16D2500/30426

  Speed of the output shaft · CPC title

• F16D2500/7044

  Output shaft torque · CPC title