Automatic transmission input clutch control

1. A method of controlling the performance of a vehicle from a stationary condition, the method comprising:

detecting the disengagement of a driver-operated braking device;

applying a friction clutch to couple an engine crankshaft of the vehicle with an input shaft of the transmission;

determining an open-loop torque command to accelerate the vehicle at a predetermined rate;

providing the open-loop torque command to an engine controller to controllably increase the input torque to the transmission;

operating a closed loop engine speed control module to prevent the crankshaft speed from slowing below a predetermined engine idle speed.

2. The method of claim 1 , further comprising reducing a transmission input torque to zero if the driver-operated braking device is re-engaged.

3. The method of claim 2 , further comprising disengaging the friction clutch to decouple the engine crankshaft from the input shaft of the transmission if the driver-operated braking device is re-engaged.

4. The method of claim 1 , further comprising performing a speed-controlled launch if the driver-operated accelerator device is engaged.

5. The method of claim 4 , wherein the speed-controlled launch includes providing a propulsion torque command to the engine controller to accelerate the vehicle at a desired launch rate.

6. The method of claim 5 , further comprising increasing an engine speed set point following the engagement of the driver-operated accelerator device.

7. The method of claim 1 , further comprising deactivating the closed loop engine speed control module if the transmission input shaft speed exceeds the predetermined engine idle speed by a predetermined threshold.

8. The method of claim 1 , wherein the provided torque command decreases as the speed of the input shaft of the transmission approaches the predetermined engine idle speed.

9. A method of controlling the performance of a vehicle from a stationary condition, the method comprising:

operating a vehicle powertrain in a creep mode following the disengagement of a driver-operated braking device; and

operating the vehicle powertrain in a launch mode following an engagement of a driver-operated acceleration device subsequent to the disengagement of the driver-operated braking device;

wherein operating a vehicle powertrain in a creep mode includes:

applying a friction clutch to couple an engine crankshaft of the vehicle powertrain with an input shaft of the transmission;

determining an open-loop torque command to accelerate the vehicle powertrain at a predetermined rate;

providing the open-loop torque command to an engine controller to controllably increase the input torque to the transmission; and

operating a closed loop engine speed control module to prevent the crankshaft speed from slowing below a predetermined engine idle speed.

10. The method of claim 9 , wherein operating a vehicle powertrain in a launch mode includes providing a propulsion torque command to the engine controller in a closed-loop manner to accelerate the vehicle at a desired launch rate.

11. The method of claim 10 , wherein operating a vehicle powertrain in a launch mode further includes increasing an engine speed set point following the engagement of the driver-operated accelerator device.

12. The method of claim 9 , further comprising deactivating the creep mode if the driver-operated braking device is re-engaged prior to the engagement of a driver-operated acceleration device.

13. The method of claim 12 , wherein deactivating the creep mode includes disengaging the friction clutch to decouple the engine crankshaft from the input shaft of the transmission.

14. The method of claim 9 , further comprising deactivating the launch mode if the speed of the transmission input shaft meets a launch controlled engine speed.

15. The method of claim 14 , wherein deactivating the launch mode includes varying the propulsion torque command directly in response to the engagement of a driver-operated acceleration device.

16. A method of controlling the performance of a vehicle from a stationary condition, the method comprising:

operating a vehicle powertrain in a creep mode following the disengagement of a driver-operated braking device; and

operating the vehicle powertrain in a launch mode following an engagement of a driver-operated acceleration device subsequent to the disengagement of the driver-operated braking device;

wherein operating a vehicle powertrain in a creep mode includes:

applying a friction clutch to couple an engine crankshaft of the vehicle powertrain with an input shaft of the transmission;

determining an open-loop torque command to accelerate the vehicle powertrain at a predetermined rate;

providing the torque command to an engine controller to controllably increase the input torque to the transmission;

operating a closed loop engine speed control module to prevent the crankshaft speed from slowing below a predetermined engine idle speed; and

wherein operating a vehicle powertrain in a launch mode includes providing a propulsion torque command to the engine controller in a closed-loop manner to accelerate the vehicle at a desired launch rate, and increasing an engine speed set point following the engagement of the driver-operated accelerator device.

17. The method of claim 16 , further comprising deactivating the creep mode if the driver-operated braking device is re-engaged prior to the engagement of a driver-operated acceleration device.

18. The method of claim 17 , wherein deactivating the creep mode includes disengaging the friction clutch to decouple the engine crankshaft from the input shaft of the transmission.

19. The method of claim 16 , further comprising deactivating the launch mode if the speed of the transmission input shaft meets a launch controlled engine speed.

20. The method of claim 19 , wherein deactivating the launch mode includes varying the propulsion torque command directly in response to the engagement of a driver-operated acceleration device.