LOAD TRANSFER ADAPTIVE TRACTION CONTROL SYSTEM

• US 20070027605A1
• Filed: 07/29/2005
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Fodor, Michael, Hrovat, Davor
• Granted Patent: US 7,873,459 B2
• Time in Patent Office: Days
• US Class Current: 701/82
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/12 including control of differentials
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2040/1307 Load distribution on each wheel suspension
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2710/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels

Abstract

A method of controlling a vehicle that includes determining a dynamic normal load for the vehicle wheel, modifying the requested torque signal from a traction control system in response to the dynamic normal load to form a modified requested torque and controlling the engine in response to the modified requested torque. The controlling may be performed using the ratio of the dynamic normal load and the steady state normal load to form the modified requested torque.

Claims

1. A method of controlling a traction control system comprising:

determining a dynamic normal load for a vehicle wheel;

modifying the requested torque from a traction control system in response to the dynamic normal load to form a modified requested torque; and

controlling a traction control system in response to the modified requested torque.

2. A method as recited in claim 1 wherein determining a dynamic normal load comprises determining a normal load in response to a lateral acceleration.

3. A method as recited in claim 1 wherein determining a dynamic normal load comprises determining a normal load in response to a longitudinal acceleration.

4. A method as recited in claim 1 wherein determining a dynamic normal load comprises determining a normal load in response to a yaw rate.

5. A method as recited in claim 1 wherein determining a dynamic normal load comprises determining a normal load in response to a yaw acceleration.

6. A method as recited in claim 1 wherein determining a dynamic normal load comprises determining a normal load in response to a difference in non-driven wheel speeds.

7. A method as recited in claim 1 wherein modifying the requested torque comprises modifying the requested torque to reduce overshoots and undershoots.

8. A method as recited in claim 1 further comprising determining a road surface coefficient of friction in response to the dynamic normal load and the requested torque.

9. A method as recited in claim 8 further comprising applying the requested torque in response to the road surface coefficient of friction.

10. A method of controlling a traction control system comprising:

determining a dynamic normal load for a vehicle wheel;

determining a steady state normal load;

determining a ratio in response to the dynamic normal load and the steady state normal load; and

modifying the requested torque from the traction control system in response to the ratio.

11. A method as recited in claim 10 wherein determining a ratio comprises determining a present ratio and a previous ratio.

12. A method as recited in claim 10 wherein modifying the requested torque comprises modifying a proportional term requested torque in response to the ratio.

13. A method as recited in claim 10 wherein modifying the requested torque comprises modifying an integral term requested torque in response to the ratio.

14. A method as recited in claim 10 further comprising determining a road surface coefficient of friction in response to the dynamic normal load.

15. A method as recited in claim 14 further comprising applying the requested torque in response to the ratio and the road surface coefficient of friction.

16. A method as recited in claim 10 further comprising using the computed dynamic normal load to adjust a triggering threshold used to activate the traction control system.

17. A method as recited in claim 16 wherein determining when the normal load on an inside wheel is changing comprises determining when the normal load on an inside wheel is decreasing, and wherein modifying the triggering threshold when the normal load on the inside wheel is changing comprises increasing the triggering threshold when the normal load on the inside wheel is decreasing.

18. A method as recited in claim 10 wherein determining a dynamic normal load comprises determining a normal load in response to a lateral acceleration or to a longitudinal acceleration.

19. A method as recited in claim 10 wherein determining a dynamic normal load comprises determining a normal load in response to a yaw rate or to a yaw acceleration.

20. A method as recited in claim 10 wherein determining a dynamic normal load comprises determining a normal load in response to a difference in non-driven wheel speeds.