Automatic control of driveline states

Patent metadata

Field	Value
Publication number	US-10166865-B2
Application number	US-201414264389-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Oct 18, 2010
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

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.

First claim

The invention claimed is:

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.

Assignees

• Ford Global Tech Llc

Inventors

• Rodrigues Ashok E
• Perakes Andreas E
• Bruns Richard D
• Ward Derek K
• Koppenol Jim
• Mccubbin Nicholas E
• Grutter Peter J

Classifications

• B60W2552/40

  Coefficient of friction · CPC title

• B60W2555/20

  Ambient conditions, e.g. wind or rain · CPC title

• B60K23/08 Primary

  for changing number of driven wheels {, for switching from driving one axle to driving two or more axles (B60K17/3515 takes precedence)} · CPC title

• B60W2552/35

  Road bumpiness, e.g. potholes · CPC title

• B60K23/0808

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title