Automatic control of driveline states

• US 10,166,865 B2
• Filed: 04/29/2014
• Issued: 01/01/2019
• Est. Priority Date: 10/18/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Rodrigues, Ashok E., Perakes, Andreas E., Bruns, Richard D., Ward, Derek K., Koppenol, Jim, McCubbin, Nicholas E., Grutter, Peter J.
• Primary Examiner(s): Smith, Jelani A
• Assistant Examiner(s): Wallace, Donald J
• Application Number:
  US14/264,389
• Publication Number:
  US 20140236443A1
• Time in Patent Office: 1,708 Days
• CPC Class Codes: B60K 2023/085 automatically actuated
• CPC Class Codes: B60K 23/08 for changing number of driven wheels , for switching from driving one axle to driving two or more axles B60K17/3515 takes precedence
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: B60K 28/165 acting on elements of the vehicle drive train other than the propulsion unit and brakes, e.g. transmission, clutch, differential acting on brakes B60T8/17
• CPC Class Codes: B60W 2552/35 Road bumpiness, e.g. potholes
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60Y 2300/28 related to towing or towed situations

Abstract

A method for controlling a vehicle driveline uses sensors to estimate a need for powering secondary wheels for each of a plurality of conditions. The estimates are scaled and the scaled estimates summed. Only primary wheels are powered when the summed estimates are less than a reference value. Both the primary and secondary wheels are powered when the summed estimates exceed the reference value.

Claims

1. A method for controlling a vehicle driveline comprising:

determining demands to power secondary wheels for each of a plurality of vehicle related conditions detected by sensors;

scaling the demands for each condition;

summing the scaled demands;

powering only primary wheels when the summed demands are less than a reference value;

powering the primary and secondary wheels when the summed demands equal or exceed the reference value.

2. The method of claim 1 further comprising:

powering only the primary wheels by maintaining a drive connection between a transmission output and the primary wheels and producing a drive disconnection between the transmission output and the secondary wheels;

powering the primary and secondary wheels by maintaining the drive connection between the transmission output and the primary wheels and producing a drive connection between the transmission output and the secondary wheels.

3. The method of claim 1 further comprising:

determining a need for powering the secondary wheels as a function of wheel slip.

4. The method of claim 1 further comprising:

determining a need for powering the secondary wheels as a function of vehicle dynamic handling support.

5. The method of claim 1 further comprising:

setting an integral value for one of the conditions as zero;

using the demand for the condition to adjust the zero integral value as a function of time;

maintaining power to the secondary wheels until the integral value returns to zero.

6. The method of claim 1 further comprising:

varying a rate of driveline connection for powering the secondary wheels as a function of the scaled demands and whether a fast connect condition is present.

7. The method of claim 1 further comprising:

powering the primary and secondary wheels when the summed demands are less than the reference value and an engagement history value exceeds a historical reference rate.

8. The method of claim 1 further comprising:

powering only the primary wheels as a function of a forced disconnect condition.

9. The method of claim 1 further comprising:

powering the primary and secondary wheels as a function of a forced connect condition.

10. The method of claim 1 further comprising:

determining a need for powering the secondary wheels as a function of a vehicle, road, or weather condition.

11. The method of claim 1 further comprising:

weighting the demands as a function of priority of each of the demands being relatively more or less critical for needing to power the secondary wheels.

12. A method for controlling a vehicle driveline comprising:

using current vehicle operating, road, and weather conditions to determine a probability as to whether powering secondary wheels is needed;

automatically powering only primary wheels when the probability is below a predetermined probability and a forced connect condition is absent;

automatically powering only the primary wheels when the probability is above the predetermined probability and a forced disconnect condition based on the current vehicle operating conditions is present;

automatically engaging the driveline to power the primary and secondary wheels when the probability is above the predetermined probability and a forced disconnect condition based on the current vehicle operating conditions is absent;

automatically engaging the driveline to power the primary and secondary wheels when the probability is below the predetermined probability and a forced connect condition is present.

13. The method of claim 12 further comprising:

powering only the primary wheels by maintaining a drive connection between a transmission output and the primary wheels, producing a drive disconnection between the transmission output and a driveshaft, and producing a drive disconnection between the driveshaft and axle shafts of the secondary wheels;

powering the primary and secondary wheels by maintaining the drive connection between the transmission output and the primary wheels, producing a drive connection between the transmission output and the drive shaft, and producing a drive connection between the drive shaft and the axle shafts of the secondary wheels.

14. The method of claim 12 further comprising:

needing to power the secondary wheels as a function of wheel slip.

15. The method of claim 12 further comprising:

needing to power the secondary wheels as a function of vehicle dynamic handling support.

16. The method of claim 12 further comprising:

setting an integral value for one of the conditions as zero;

using the probability to adjust the zero integral value as a function of time;

maintaining powering the secondary wheels until the integral value returns to zero.

17. The method of claim 12 further comprising:

varying a rate of driveline connection for powering the secondary wheels as a function of the current vehicle operating, road, and weather conditions and whether a fast connect condition is present.

18. The method of claim 12 further comprising:

powering the primary and secondary wheels when the probability is below the predetermined probability, a forced disconnect condition is absent, and an engagement history value exceeds a historical reference rate.

19. The method of claim 12 further comprising:

determining the probability as a function of a plurality of vehicle operating, road, or weather conditions.

20. The method of claim 19 further comprising:

weighting the vehicle operating, road and weather conditions as a function of each of the vehicle operating, road and weather conditions being relatively of more or less critical for needing to power the secondary wheels.