Granted Patent B2

US 8,412,426 · App. 12/399,503 · Granted Apr 2, 2013

Abstract

Claims (54)

1. A method for executing a clutch-to-clutch shift in a hybrid transmission from an initial operating mode, characterized by an off-going clutch, to a target operating mode, characterized by an on-coming clutch, the method comprising:

commanding fluid be distributed to the on-coming clutch;

determining if the shift is completed using the on-coming clutch;

determining if an over/under speed ratio is needed if the shift operation is completed using the on-coming clutch;

determining on-coming clutch slip speed and acceleration profiles;

determining if an on-coming clutch slip sign is correct;

determining if the on-coming clutch is filled;

calculating an off-going clutch torque and exhausting the off-going clutch if said on-coming clutch slip sign is correct and the on-coming clutch is filled;

determining if an on-coming clutch slip is less than a predetermined slip threshold; and

locking the on-coming clutch if said on-coming clutch slip is less than said predetermined slip threshold.

2. The method of claim 1 , wherein a slip speed across the on-coming and off-going clutches is non-zero throughout substantially the entire shift operation.

3. The method of claim 2 , wherein said slip speed across the on-coming and off-going clutches is controlled by adjusting input torque from at least one of an engine and a motor each operatively connected to the transmission.

4. The method of claim 1 , wherein said over/under speed ratio is needed if the shift operation is completed using the on-coming clutch and the shift operation is one of a power-on downshift or a power-off upshift.

5. The method of claim 1 , wherein said on-coming clutch slip speed and acceleration profiles are determined based at least in part upon said over/under speed ratio if said over/under speed ratio is needed, and wherein said on-coming clutch slip and acceleration profiles are determined without said over/under speed ratio if said over/under speed ratio is not needed.

6. The method of claim 5 , wherein said on-coming clutch slip speed profile first targets a slip speed equivalent of said over/under speed ratio and subsequently retargets to zero to engage the on-coming clutch when clutch torque is exchanged between the on-coming and off-going clutch if said over/under speed ratio is needed.

7. The method of claim 1 , wherein said on-coming clutch slip sign is correct if a sign of said output torque command is the same as said on-coming clutch slip sign.

8. The method of claim 1 , further comprising:

determining transmission input speed and acceleration profiles.

9. The method of claim 8 , wherein said determining said input speed and acceleration profiles is based at least in part upon profile calibrations and an initial speed and a target speed of the on-coming clutch.

10. The method of claim 9 , wherein said input speed and acceleration profiles include a time-based change in speed of the on-coming clutch comprising a three-segment profile, wherein a first segment comprises a ramp up in speed of the oncoming clutch, a second segment comprises a steady state change in speed of the oncoming clutch, and a third segment comprises a ramp down in speed of the oncoming clutch.

11. The method of claim 1 , further comprising:

controlling an input speed of the transmission; and

controlling an on-coming clutch speed;

wherein said transmission input speed and said on-coming clutch speed are controlled via at least one of an engine and a motor each operatively connected to the transmission.

12. The method of claim 1 , wherein if the shift operation is not completed using the on-coming clutch, the method further comprises:

slipping the off-going clutch;

determining said on-coming clutch slip speed and acceleration profiles based at least in part upon said over/under speed ratio;

determining if said on-coming clutch slip sign is correct;

determining if the on-coming clutch is filled; and

locking the on-coming clutch and exhausting the off-going clutch if said on-coming clutch slip sign is correct and the on-coming clutch is filled.

13. The method of claim 12 , wherein slipping the off-going clutch includes controlling a current torque capacity of the off-going clutch to below reactive torque.

14. The method of claim 12 , further comprising:

controlling an input speed of the transmission and an on-coming clutch speed prior to applying said off-going clutch torque;

wherein said transmission input speed and said on-coming clutch speed are controlled via at least one of an engine and a motor each operatively connected to the transmission.

15. The method of claim 12 , wherein the off-going clutch is controllably slipped prior to slipping the on-coming clutch if the shift operation is not completed using the on-coming clutch.

16. A method for executing a shift from an initial operating mode to a target operating mode in a multi-mode, electrically variable, hybrid transmission having at least an off-going clutch and an on-coming clutch clutches and operable to receive torque from an engine and at least one motor/generator assembly, the initial operating mode characterized by the off-going clutch in an applied state simultaneous with the on-coming clutch in a released state, and the target operating mode characterized by the off-going clutch in a released state simultaneous with the on-coming clutch in an applied state, the method comprising:

filling the on-coming clutch to a predetermined pre-fill level;

determining if the shift is completed using the on-coming clutch or the off-going clutch;

slipping the off-going clutch prior to slipping the on-coming clutch if the shift operation is completed using the off-going clutch;

determining if an over/under speed ratio is needed if the shift operation is completed using the on-coming clutch;

determining on-coming clutch slip speed and acceleration profiles based upon said over/under speed ratio if the shift operation is completed using the off-going clutch or the shift operation is completed using the on-coming clutch and said over/under speed ratio is needed, said on-coming clutch slip speed and acceleration profiles being determined without said over/under speed ratio if the shift operation is completed using the on-coming clutch and said over/under speed ratio is not needed;

determining if an on-coming clutch slip sign is correct;

determining if the on-coming clutch is filled;

calculating and applying an off-going clutch torque based at least in part upon an output torque command;

locking the on-coming clutch and exhausting the off-going clutch if the shift operation is completed using the off-going clutch, said on-coming clutch slip sign is correct, and the on-coming clutch is filled;

determining if an on-coming clutch slip is less than a predetermined slip threshold and exhausting the off-going clutch if the shift operation is completed using the on-coming clutch, said on-coming clutch slip sign is correct, and the on-coming clutch is filled; and

locking the on-coming clutch if the shift operation is completed using the on-coming clutch and said on-coming clutch slip is less than said predetermined slip threshold.

17. The method of claim 16 , further comprising:

controlling an input speed of the transmission and an on-coming clutch speed by adjusting torque input of at least one of the engine and the motor/generator assembly;

wherein said controlling said transmission input speed and said on-coming clutch speed is performed prior to exhausting the off-going clutch if the shift operation is completed using the off-going clutch; and

wherein said controlling said transmission input speed and said on-coming clutch speed is performed after exhausting the off-going clutch if the shift operation is completed using the on-coming clutch.

18. The method of claim 16 , wherein a slip speed across the on-coming and off-going clutches is non-zero throughout substantially the entire shift operation.

19. The method of claim 16 , further comprising:

determining transmission input speed and acceleration profiles prior to said determining if the shift operation is completed using the on-coming clutch or the off-going clutch.

Assignments (8)