Control of an electronic locking differential

• US 9,605,740 B2
• Filed: 10/01/2009
• Issued: 03/28/2017
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Povirk, Jacob M., Andonian, Brian J., Torres, Joseph J., Walega, Kenneth G.
• Primary Examiner(s): Edwards, Jerrah
• Assistant Examiner(s): Han, Charles J
• Application Number:
  US12/571,590
• Publication Number:
  US 20110082634A1
• Time in Patent Office: 2,735 Days
• Field of Search: 701/50, 701/58, 701/69, 701/82, 701/89, 701/91, 180/6.64, 180/24.09, 180/197, 180/249, 180/235, 303/163
• US Class Current: 1/1
• CPC Class Codes: B60K 17/344 having a transfer gear
• CPC Class Codes: B60K 23/04 for differential gearing
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/24 using positive clutches or brakes
• CPC Class Codes: F16H 48/30 using externally-actuatable means

Abstract

A method for controlling a locking differential of a motor vehicle includes locking the differential, if vehicle speed is less than a reference speed, and a wheel speed differential due to wheel slip is greater than a reference speed; and unlocking the differential and preventing its engagement, if vehicle speed is greater than the reference speed, and said wheel speed differential is less than a reference speed.

Claims

1. A method for controlling a locking differential of a motor vehicle, comprising the steps of:

(a) locking the differential, provided vehicle speed is less than a reference speed, yaw acceleration of the vehicle is greater than a reference yaw acceleration, and a wheel speed differential is greater than a reference wheel speed differential; and

(b) unlocking the differential and preventing its engagement, provided vehicle speed is not less than the reference speed, or yaw acceleration of the vehicle is not greater than the reference yaw acceleration or the wheel speed differential is not greater than the reference wheel speed differential.

2. The method of claim 1, wherein step (b) further comprises unlocking the differential and preventing its engagement, provided that any of the conditions in step (b) are met, or that an angular displacement of a steering wheel from a centered position is less than a reference angle and lateral acceleration of the vehicle is less than a reference lateral acceleration.

3. The method of claim 1, wherein step (a) further comprises locking the differential, provided that the conditions of step (a) are met and that an angular displacement of a steering wheel from a centered position is greater than a reference angle, and that lateral acceleration of the vehicle is greater than a reference lateral acceleration.

4. The method of claim 1, wherein step (a) further comprises determining that an angular displacement of a steering wheel from a centered position is less than a reference angle and an engine throttle displacement is greater than a reference displacement.

5. The method of claim 1, wherein step (a) further comprises automatically applying wheel brakes if the wheel speed differential is greater than the reference wheel speed differential.

6. The method of claim 2, wherein the reference angle is about 2 degrees, and the reference lateral acceleration is about 0.1 g.

7. The method of claim 4, wherein the reference angle is about 2 degrees, and the reference displacement of the engine throttle is about 25 percent.

8. A method for controlling a locking differential of a motor vehicle, comprising the steps of:

(a) locking the differential, provided yaw acceleration of the vehicle is greater than a reference yaw acceleration and a wheel speed differential is greater than a reference wheel speed differential; and

(b) unlocking the differential and preventing its engagement, provided vehicle speed is not less than a reference speed, or yaw acceleration of the vehicle is not greater than the reference yaw acceleration or a wheel speed differential is not greater than the reference wheel speed differential.

9. The method of claim 8, wherein step (b) further comprises unlocking the differential and preventing its engagement, provided that any of the conditions in step (b) are met, or that an angular displacement of a steering wheel from a centered position is less than a reference angle and lateral acceleration of the vehicle is less than a reference lateral acceleration.

10. The method of claim 8, wherein step (a) further comprises locking the differential, provided that the conditions of step (a) are met and that an angular displacement of a steering wheel from a centered position is greater than a reference angle, and that lateral acceleration of the vehicle is greater than a reference lateral acceleration.

11. The method of claim 8, wherein step (a) further comprises automatically applying wheel brakes if the wheel speed differential is greater than the reference wheel speed differential.

12. The method of claim 8, wherein step (a) further comprises determining that an angular displacement of a steering wheel from a centered position is less than a reference angle and an engine throttle displacement is greater than a reference displacement.