Reducing Oscillations in a Motor Vehicle Driveline

• US 20100268429A1
• Filed: 04/17/2009
• Published: 10/21/2010
• Est. Priority Date: 04/17/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bruns, Richard D., Barrette, Peter J., Lee, Syun K., Rodrigues, Ashok
• Granted Patent: US 8,095,288 B2
• Time in Patent Office: Days
• US Class Current: 701/69
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: B60W 10/119 including control of all-wheel-driveline means, e.g. transfer gears or clutches for dividing torque between front and rear axle B60W10/14 takes precedence
• CPC Class Codes: B60W 2050/0009 Proportional differential [PD] controller
• CPC Class Codes: B60W 2520/263 Slip values between front and rear axle
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline

Abstract

A method for reducing oscillations in a vehicle driveline includes transmitting torque to secondary wheels of the vehicle, determining a first rate of change in speed between the secondary wheels and primary wheels, if a second rate of change in speed between secondary wheels and primary wheels is greater than the first rate of change, reducing torque transmitted to the secondary wheels proportional to a ratio of the first rate of change and the second rate of change, and if the second rate of change is less than the first rate of change, using differential and proportional control to change said torque.

Claims

1. A method for reducing oscillations in a vehicle driveline comprising:

(a) transmitting torque to secondary wheels of the vehicle;

(b) determining a first rate of change in speed between the secondary wheels and primary wheels;

(c) if a second rate of change in speed between secondary wheels and primary wheels is greater than the first rate of change, reducing torque transmitted to the secondary wheels proportional to a ratio of the first rate of change and the second rate of change;

(d) if the second rate of change is less than the first rate of change, using differential and proportional control to change said torque.

2. The method of claim 1 wherein:

the first rate of change is a first rate of change in an average speed of the secondary wheels and an average speed of the primary wheels;

the second rate of change is a second rate of change in an average speed of the secondary wheels and an average speed of the primary wheels.

3. The method of claim 1 wherein step (d) further comprises changing said torque using a differential gain multiplied by the second rate of change plus a proportional gain multiplied by a difference between an average of a speed of the secondary wheels and an average speed of the primary wheels.

4. The method of claim 3 wherein:

the first rate of change is a first rate of change in an average speed of the secondary wheels and an average speed of the primary wheels;

the second rate of change is a second rate of change in an average speed of the secondary wheels and an average speed of the primary wheels.

5. The method of claim 1 further comprising terminating the method if the torque transmitted to the secondary axle is less than a reference torque.

6. The method of claim 1 further comprising terminating the method if a position of an accelerator pedal is less than a reference accelerator pedal position.

7. A method for reducing oscillations in a vehicle driveline comprising:

(a) transmitting torque to secondary wheels of the vehicle;

(b) determining a first rate of change between in an average speed of the secondary wheels and an average speed of the primary wheels;

(c) if a second rate of change between an average speed of the secondary wheels and an average speed of the primary wheels is greater than the first rate of change, reducing torque transmitted to the secondary wheels proportional to a ratio of the first rate of change and the second rate of change;

(d) if the second rate of change is less than the first rate of change, using differential and proportional control to change said torque.

8. The method of claim 7 wherein step (d) further comprises changing said torque using a differential gain multiplied by the second rate of change plus a proportional gain multiplied by a difference between an average of a speed of the secondary wheels and an average speed of the primary wheels.

9. The method of claim 7 further comprising terminating the method if the torque transmitted to the secondary axle is less than a reference torque.

10. The method of claim 7 further comprising terminating the method if a position of an accelerator pedal is less than a reference accelerator pedal position.

11. A system for controlling a vehicle driveline, comprising:

primary wheels and secondary wheels;

a clutch for transmitting torque to the secondary wheels;

a controller configured to determine a first rate of change in speed between the secondary wheels and primary wheels;

reduce said torque in proportion to a ratio of the first rate of change and the second rate of change, if a second rate of change in speed between secondary wheels and primary wheels is greater than the first rate of change; and

use differential and proportional control to change said torque, if the second rate of change is less than the first rate of change.

12. The system of claim 11 wherein:

the controller is further configured to determine the first rate of change using a first rate of change in an average speed of the secondary wheels and an average speed of the primary wheels, and to determine the second rate of change using a second rate of change in an average speed of the secondary wheels and an average speed of the primary wheels.

13. The method of claim 11 wherein the controller is further configured to change said torque using a differential gain multiplied by the second rate of change plus a proportional gain multiplied by a difference between an average of a speed of the secondary wheels and an average speed of the primary wheels.

14. The system of claim 13 wherein:

the controller is further configured to determine the first rate of change using a first rate of change in an average speed of the secondary wheels and an average speed of the primary wheels, and to determine the second rate of change using a second rate of change in an average speed of the secondary wheels and an average speed of the primary wheels.

15. The system of claim 11 wherein the controller is further configured to terminate the method if the torque transmitted to the secondary axle is less than a reference torque.

16. The system of claim 11 wherein the controller is further configured to if a position of an accelerator pedal is less than a reference accelerator pedal position.

17. The system of claim 11 further comprising:

first sensors, each first sensor communicating with the controller and producing a signal representing a speed of one of the primary wheels;

second sensors, each second sensor communicating with the controller and producing a signal representing a speed of one of the secondary wheels.

18. The system of claim 17 further comprising:

an accelerator pedal;

a sensor communicating with the controller and producing a signal representing a position of the accelerator pedal.