Real time estimation algorithm for torque converter clutch feed forward pressure for ECCC control

1. Method to control torque converter slip in a powertrain comprising a torque generative device and a torque converter comprising an impeller, a turbine and a torque converter clutch, the method comprising:

during a transition of a speed of the torque generative device, monitoring a desired slip for the transition;

monitoring a turbine speed of the torque converter;

determining a turbine torque based upon the desired slip and the turbine speed;

determining a feed forward torque converter clutch pressure command based upon the turbine torque, a torque generative device torque, and a torque converter clutch gain; and

controlling the torque converter clutch based upon the feed forward torque converter clutch pressure command.

2. The method of claim 1 , wherein determining the turbine torque based upon the desired slip and the turbine speed comprises utilizing a turbine torque determination selected from the group consisting of a Kotwicki model and a K-factor look-up table.

3. Method to control torque converter slip in a powertrain comprising a torque generative device and a torque converter comprising an impeller, a turbine and a torque converter clutch, the method comprising:

during a transition of a speed of the torque generative device, monitoring operation of the powertrain, comprising;

monitoring a desired slip for the transition;

monitoring a transmission input speed; and

monitoring an engine torque;

utilizing a Kotwicki model to estimate a turbine torque based upon the monitored operation of the powertrain;

determining a feed forward torque converter clutch pressure command based upon the turbine torque; and

controlling the torque converter clutch based upon the feed forward torque converter clutch pressure command.

4. The method of claim 3 , wherein monitoring operation of the powertrain further comprises:

determining a desired engine speed based upon the reference slip and the transmission input speed.

5. The method of claim 3 , wherein determining the feed forward torque converter clutch pressure based upon the turbine torque comprises:

determining a torque converter clutch torque based upon the turbine torque and the engine torque; and

determining the feed forward torque converter clutch pressure based upon the torque converter clutch torque and a torque converter clutch gain.

6. The method of claim 3 , wherein controlling the torque converter clutch is further based upon a feedback torque converter clutch pressure command.

7. The method of claim 6 , wherein the feedback torque converter clutch pressure command is disabled during rapid transients to the powertrain.

8. The method of claim 3 , wherein determining the feed forward torque converter clutch pressure command comprises:

monitoring a tip in event of the powertrain; and

modulating the feed forward torque converter clutch pressure command based upon a desired slip level based upon the tip in event.

9. The method of claim 3 , wherein monitoring operation of the powertrain comprises:

monitoring an engine speed; and

monitoring a transmission input speed;

wherein utilizing the Kotwicki model to estimate a turbine torque comprises:

determining a region of the Kotwicki model based upon the engine speed and the transmission input speed; and

utilizing the Kotwicki model based upon the determined region.

10. The method of claim 9 , wherein determining the region of the Kotwicki model comprises selecting between a converter mode in drive, a coupling mode in drive, and a coast mode in coast.

11. System to control torque converter slip in a powertrain comprising a torque generative device and a torque converter comprising an impeller, a turbine and a torque converter clutch, the system comprising:

said torque converter clutch; and

a control module:

during a transition of a speed of the torque generative device, monitoring a desired slip of the torque converter for the transition;

monitoring a transmission input speed;

determining a torque converter torque based upon the reference slip and the transmission input speed;

monitoring an engine torque;

determining a torque converter clutch torque based upon the torque converter torque and the engine torque;

determining a feed forward torque converter clutch pressure based upon the torque converter clutch torque and a torque converter clutch gain; and

utilizing the feed forward torque converter clutch pressure to control the torque converter clutch.

12. The system of claim 11 , wherein the control module determining the torque converter torque comprises utilizing a Kotwicki model.

13. The system of claim 11 , wherein the control module determining the torque converter torque comprises utilizing a K-factor look-up table.

14. The system of claim 11 , wherein the torque generative device comprises an engine.