Granted Patent B2

US 8,221,285 · App. 12/251,463 · Granted Jul 17, 2012

Abstract

Claims (48)

1. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said method comprising:

commanding a shift from a first operating range state to a second operating range state;

identifying an off-going clutch;

controlling torque output from said electric machine to offload reactive torque transmitted through said off-going clutch;

selectively applying an oncoming clutch to offload reactive torque transmitted through said off-going clutch; and

reducing a clutch torque capacity of said off-going clutch when said reactive torque transmitted through said off-going clutch is substantially zero.

2. The method of claim 1 , further comprising controlling torque output from a second electric machine to off-load reactive torque transmitted through said off-going clutch.

3. The method of claim 1 , wherein selectively applying said oncoming clutch is based upon a torque required to assist said electric machine to fully offload reactive torque transmitted through said off-going clutch.

4. The method of claim 3 , further comprising applying an engine torque based upon a torque required to assist said electric machine and said oncoming clutch to fully offload reactive torque transmitted through said off-going clutch.

5. The method of claim 1 , wherein selectively applying said oncoming clutch is based upon determining that said oncoming clutch will reduce reactive torque in said off-going clutch.

6. The method of claim 5 , wherein determining that said oncoming clutch will reduce reactive torque in said off-going clutch is based upon monitoring slip speed in said oncoming clutch.

7. The method of claim 1 , wherein selectively applying said oncoming clutch is based upon determining a clutch energy limit and limiting said applying said oncoming clutch based upon said clutch energy limit.

8. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said method comprising:

initiating a shift event comprising

identifying an off-going clutch to be synchronously offloaded, and

identifying an oncoming clutch to be loaded;

monitoring an electric machine torque capability to offload said off-going clutch;

determining a torque required to assist said electric machine to offload said off-going clutch;

applying torque with said electric machine to offload said off-going clutch; and

selectively applying torque through said oncoming clutch based upon said torque required to assist said electric machine to offload said off-going clutch.

9. The method of claim 8 ,

wherein monitoring an electric machine torque capability to offload said off-going clutch comprises

monitoring a torque capability for said electric machine, and

monitoring a torque capability of a second electric machine; and

further comprising applying torque with said second electric machine to offload said off-going clutch.

10. The method of claim 8 , further comprising:

determining a torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch; and

applying torque with said engine based upon said determining said torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch.

11. The method of claim 8 , further comprising:

determining a clutch energy limit based upon intended operation of said oncoming clutch; and

wherein said selectively applying torque through said oncoming clutch is further based upon said clutch energy limit.

12. Apparatus for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said apparatus comprising:

an identified off-going clutch;

an identified oncoming clutch; and

a powertrain control system including programming to

monitor a torque capability of said electric machine to offload reactive torque from said off-going clutch,

determine a torque required to assist said electric machine to offload said off-going clutch,

command torque from said electric machine to offload said off-going clutch, and

selectively command torque through said oncoming clutch based upon said torque required to assist said electric machine to offload said off-going clutch.

13. The apparatus of claim 12 , wherein said powertrain control system further includes programming to

monitor a torque capability of a second electric machine to offload reactive torque from said off-going clutch, and

command torque from said second electric machine to offload said off-going clutch.

14. The apparatus of claim 12 , wherein said powertrain control system further includes programming to

determine a torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch, and

command torque from said engine based upon said determining said torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch.

15. The apparatus of claim 12 , wherein said powertrain control system further includes programming to

determine a clutch energy limit based upon intended operation of said oncoming clutch, and

limit said selectively commanded torque through said oncoming clutch based upon said clutch energy limit.

Assignments (17)