Vehicle control including control over a rate of torque decrease

Patent metadata

Field	Value
Publication number	US-9682702-B2
Application number	US-201414898408-A
Country	US
Kind code	B2
Filing date	May 22, 2014
Priority date	Jun 14, 2013
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A method of controlling a vehicle includes determining whether control over a rate of torque decrease is desired in order to improve the vehicle behavior. The rate of torque decrease is controlled to stay within a range of a selected rate of change. A vehicle control system includes a controller configured to determine whether control over a rate of torque decrease is desired. The controller is also configured to control the rate of torque decrease to stay within a range of a selected rate of change.

First claim

The invention claimed is:

1. A method of controlling a vehicle, comprising:
determining whether control over a rate of torque decrease is desired by predicting lift-off oversteer,
wherein predicting lift-off oversteer comprises determining whether the vehicle is turning and determining whether a friction value that is associated with a surface that vehicle wheels contact as the vehicle is moving is below a threshold; and
in response to determining that a rate of powertrain torque decrease is required, decreasing torque applied to the powertrain and controlling the rate of torque decrease to stay within a range of a selected rate of change.

2. The method of claim 1 , wherein the threshold indicates wheel slip.

3. The method of claim 1 , wherein the threshold corresponds to a limit of cornering adhesion.

4. The method of claim 1 , wherein the determining comprises at least one of detecting or predicting a downshift in a transmission of the vehicle.

5. The method of claim 1 , comprising controlling the rate of torque decrease based on at least one of
a current surface friction;
a current vehicle lateral acceleration; or
a current vehicle speed.

6. The method of claim 1 , wherein the selected rate of change addresses lift-off oversteer by at least one of avoiding lift-off oversteer, minimizing lift-off oversteer or reducing lift-off oversteer.

7. The method of claim 1 , comprising
determining a plurality of different rate limits for different conditions, respectively; and utilizing different ranges surrounding the selected rate limit based on the condition.

8. A vehicle control system, comprising:
a powertrain; and
a controller configured to:
determine whether control over a rate of torque decrease is desired by predicting lift-off oversteer, wherein predicting lift-off oversteer comprises determining whether the vehicle is turning and determining whether a friction value that is associated with a surface that vehicle wheels contact as the vehicle is moving is below a threshold; and
in response to determining that a rate of powertrain torque decrease is required, decrease torque applied to the powertrain and control the rate of torque decrease to stay within a range of a selected rate of change.

9. The system of claim 8 , wherein the threshold indicates wheel slip.

10. The system of claim 8 , wherein the threshold corresponds to a limit of cornering adhesion.

11. The system of claim 8 , wherein
the powertrain comprises a transmission; and
the controller is configured to detect or predict a downshift in the transmission.

12. The system of claim 8 , wherein the controller is configured to control the rate of torque decrease based on at least one of:
a current surface friction;
a current vehicle lateral acceleration; or
a current vehicle speed.

13. The system of claim 8 , wherein the selected rate of change addresses lift-off oversteer by at least one of avoiding lift-off oversteer, minimizing lift-off oversteer or reducing lift-off oversteer.

14. The system of claim 8 , wherein the controller is configured to determine a plurality of different rate limits for different conditions, respectively; and
utilize different ranges surrounding the selected rate limit based on the condition.

15. A vehicle, comprising:
a vehicle control system, including:
a powertrain; and
a controller configured to determine whether control over a rate of torque decrease is desired by predicting lift-off oversteer,
wherein predicting lift-off oversteer comprises determining whether the vehicle is turning and determining whether a friction value that is associated with a surface that vehicle wheels contact as the vehicle is moving is below a threshold; and
in response to determining that a rate of powertrain torque decrease is required, decreasing torque applied to the powertrain and controlling the rate of torque decrease to stay within a range of a selected rate of change.

16. The vehicle of claim 15 , comprising a plurality of wheels that are driven by the powertrain and wherein the selected rate of change corresponds to at least one of the wheels having a desired frictional engagement with a surface over which the vehicle is moving.

Assignees

• Jaguar Land Rover Ltd

Inventors

• Beever Paul

Classifications

• B60W2710/0672

  Torque change rate · CPC title

• Y02T10/84

  Data processing systems or methods, management, administration · CPC title

• B60W30/02 Primary

  Control of vehicle driving stability · CPC title

• B60W30/045 Primary

  Improving turning performance · CPC title

• B60W2520/26

  Wheel slip · CPC title