Method and apparatus to control off-going clutch torque during torque phase for a hybrid powertrain system
First Claim
1. Method for controlling an electro-mechanical transmission through an unlocking state of a clutch, the 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:
- decreasing a reactive torque acting upon said clutch, said decreasing said reactive torque comprisingoverriding torque commands to said engine, andoverriding torque commands to said electric machine; and
simultaneously decreasing a clutch torque capacity, comprisingin a lead period selected according to an engine command reaction time, commanding an intermediate clutch torque command maintaining sufficient clutch torque capacity to exceed an initial reactive torque calculated at an initiation of said unlocking state, andin a second period following said lead period, progressively decreasing through a ramp down said clutch torque capacity, said decreasing said clutch torque capacity maintaining sufficient clutch torque capacity to exceed said decreasing reactive torque.
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Abstract
A method for controlling an electro-mechanical transmission through an unlocking state of a clutch, the transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member includes decreasing a reactive torque acting upon the clutch, including overriding torque commands to the engine and to the electric machine, and simultaneously decreasing a clutch torque capacity, including, during a lead period selected according to an engine command reaction time, commanding an intermediate clutch torque command maintaining sufficient clutch torque capacity to exceed an initial reactive torque calculated at an initiation of the unlocking state, and following the lead period, decreasing through a ramp down the clutch torque capacity, maintaining sufficient clutch torque capacity to exceed the decreasing reactive torque.
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Citations
16 Claims
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1. Method for controlling an electro-mechanical transmission through an unlocking state of a clutch, the 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:
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decreasing a reactive torque acting upon said clutch, said decreasing said reactive torque comprising overriding torque commands to said engine, and overriding torque commands to said electric machine; and simultaneously decreasing a clutch torque capacity, comprising in a lead period selected according to an engine command reaction time, commanding an intermediate clutch torque command maintaining sufficient clutch torque capacity to exceed an initial reactive torque calculated at an initiation of said unlocking state, and in a second period following said lead period, progressively decreasing through a ramp down said clutch torque capacity, said decreasing said clutch torque capacity maintaining sufficient clutch torque capacity to exceed said decreasing reactive torque. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Method for controlling an electro-mechanical transmission comprising a clutch and 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:
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upon initiation of an unlocking state, imposing a clutch reactive torque lead immediate maximum override upon engine torque commands, thereby ramping down, after an engine command response time, an input torque; simultaneously imposing through a lead period a clutch reactive torque immediate maximum override upon electric machine torque commands fixed at an initial reactive torque calculated at an initiation of said unlocking state; after said lead period, imposing a second clutch reactive torque immediate maximum override upon electric machine torque commands, thereby ramping down an electric machine torque; and simultaneously decreasing a clutch torque capacity, comprising through said lead period, maintaining said clutch torque capacity to exceed said initial reactive torque by at least an offset value, and after said lead period, decreasing said clutch torque capacity through a ramp down calibrated to maintain said clutch torque capacity in excess of an estimated reactive torque; wherein said lead period is calibrated to effect said ramping down said electric machine torque substantially simultaneously to said ramping down said input torque. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification