Tip-in bump reduction methods and systems
A torque converter bump control system is provided. The system includes: a gain module that computes a torque converter gain based on a speed ratio; an increased gain module that computes an increased torque converter gain based on turbine speed; a blended gain module that computes a blended torque converter gain based on the torque converter gain, the increased torque converter gain, and a blend ratio; and a final gain module that selectively sets a final torque converter gain based on the speed ratio and commanded engine torque to at least one of the torque converter gain, the increased torque converter gain, and the blended torque converter gain and wherein engine torque is controlled based on the final torque converter gain.
1. A torque converter bump control system, comprising:
a gain module that computes a torque converter gain based on a speed ratio;
an increased gain module that computes an increased torque converter gain based on turbine speed;
a blended gain module that computes a blended torque converter gain based on the torque converter gain, the increased torque converter gain, and a blend ratio; and
a final gain module that selectively sets a final torque converter gain based on the speed ratio and commanded engine torque to at least one of the torque converter gain, the increased torque converter gain, and the blended torque converter gain and wherein engine torque is controlled based on the final torque converter gain.
2. The system of claim 1 further comprising an enable module that generates an enable signal based on the speed ratio and wherein the blended gain module performs the computing of the blended torque converter gain based on the enable signal.
3. The system of claim 1 further comprising a blend ratio module that computes the blend ratio based on the speed ratio and the commanded engine torque.
4. The system of claim 3 wherein the blend ratio module selectively determines a blend rate based on commanded engine torque and wherein the blend ratio module computes the blend ratio based on the blend rate.
5. The system of claim 1 wherein the blended gain module computes the blended torque converter gain (Blended_Gain) based on a blend ratio (TC_BlendRatio), the increased torque converter gain (TC_GainIncd), the torque converter gain (TC_Gain) and based on the following equation:
Blended_Gain= TC _BlendRatio* TC _GainIncd+(1 −TC _BlendRatio)* TC _Gain.
6. The system of claim 1 wherein the final gain module sets the final torque converter gain to the increased torque converter gain when the speed ratio is less than a predetermined speed ratio threshold.
7. The system of claim 1 wherein the final gain module sets the final gain to the blended torque converter gain when the speed ratio is greater than a predetermined speed ratio threshold.
8. The system of claim 1 wherein the final gain module sets the final torque converter gain to the torque converter gain when the commanded engine torque is greater than a predetermined torque threshold.
9. The system of claim 1 further comprising an engine torque control module that controls commanded engine torque based on the final torque converter gain.
10. A method of controlling engine torque, comprising:
computing a torque converter gain based on a speed ratio;
computing an increased torque converter gain based on turbine speed;
computing a blended torque converter gain based on the torque converter gain, the increased torque converter gain, and a blend ratio; and
selectively setting a final torque converter gain equal to at least one of the torque converter gain, the increased torque converter gain, and the blended torque converter gain and wherein the selectively setting is based on the speed ratio and commanded engine torque; and
controlling engine torque based on the final torque converter gain.
11. The method of claim 10 further comprising enabling the computing of the blended torque converter gain based on the speed ratio.
12. The method of claim 10 further comprising initializing the blend ratio to one after a negative torque converter slip occurs.
13. The method of claim 12 further comprising decrementing the blend ratio by a blend rate when the speed ratio is greater than a speed ratio threshold.
14. The method of claim 13 further comprising selectively determining a blend rate based on commanded engine torque.
15. The method of claim 10 wherein the computing the blended torque converter gain (Blended_Gain) is based on a blend ratio (TC_BlendRatio), the increased torque converter gain (TC_GainIncd), the torque converter gain (TC_Gain) and based on the following equation:
Blended_Gain= TC _BlendRatio* TC _GainIncd+(1 −TC _BlendRatio)* TC _Gain.
16. The method of claim 10 wherein the selectively setting the final torque converter gain comprises setting the final torque converter gain equal to the increased torque converter gain when the speed ratio is less than a predetermined speed ratio threshold.
17. The method of claim 10 wherein the selectively setting the final torque converter gain comprises setting the final torque converter gain equal to the blended torque converter gain when the speed ratio is greater than a predetermined speed ratio threshold.
18. The method of claim 10 wherein the selectively setting the final torque converter gain comprises setting the final torque converter gain equal to the torque converter gain when the commanded engine torque is greater than a predetermined torque threshold.