Abstract: A method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an engine and an electric machine adapted to selectively transmit mechanical power to an output member through selective application of a plurality of torque-transfer clutches includes monitoring a clutch slip speed, synchronizing an oncoming clutch, and constraining reactive clutch torque limits for the oncoming clutch to achieve a reactive clutch torque that is less than an estimated clutch torque capacity.

Abstract: A method for operating a powertrain, including an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine, includes monitoring slip across a selectively applied clutch within the transmission to indicate a clutch slip event, and if the monitoring indicates the clutch slip event decreasing a load across the selectively applied clutch by reducing torque of at least one of the engine and the electric machine, in order to reduce the slip, thereby ending the clutch slip event.

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.

Abstract: A method for controlling a powertrain includes executing a shift, determining a plurality of input acceleration profiles for controlling an engine and an electric machine, determining an input speed profile, and controlling operation of the engine and the electric machine based upon the input speed profile.

Abstract: A method for controlling hydraulic line pressure of a hydraulic control system in an electromechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches includes monitoring requirements for transmission of clutch reactive torque in one of the clutches, monitoring a hydraulic line pressure within the hydraulic control system, determining a minimum clutch torque capacity required to keep the clutch from slipping, determining a hydraulic line pressure required to create the minimum clutch torque capacity, and modulating hydraulic line pressure applied to the clutch by modulating operation of the hydraulic control system based upon the hydraulic line pressure required to create the minimum clutch torque capacity.

Abstract: A method for controlling a powertrain including an electro-mechanical transmission coupled to an engine and an electric machine includes monitoring a desired input speed; signal processing the desired input speed to create a lead control signal to control the engine, wherein the signal processing includes low pass filtering the desired input speed and applying system constraint limits upon the desired input speed; signal processing the desired input speed to create an immediate control signal to control the electric machine, wherein the signal processing includes delaying the desired input speed by a lead period, low pass filtering the desired input speed, and applying system constraint limits upon the desired input speed; and controlling the powertrain through a powertrain transition based upon the lead control signal and said immediate control signal.

Abstract: A hybrid powertrain system includes a transmission operative in a plurality of operating range states. An operating range state can be secured, including assigning each operating range state to a group that can be verified, monitoring a transition path from a first to a second operating range state, and monitoring a torque equation for the present operating range state.

Abstract: A method and control system is presented to selectively actuate a plurality of clutches of a two-mode, compound-split, electro-mechanical transmission. The method comprises executing a shift operation from a first to a second operating mode and monitoring shift abort criteria. A revised shift operation is executed to control the transmission shift into a third operating mode effective to meet an operator request for output torque. The exemplary transmission has four fixed gear ratio modes and two continuously variable modes. The preferred shift abort criteria include: monitoring the operator request for output torque; identifying presence of a fault in an oncoming torques transfer device effective to facilitate operation in the second operating mode; monitoring an optimization routine for managing torque inputs from the plurality of torque-generative devices.

Abstract: A method and control system is presented to selectively actuate a plurality of clutches of a two-mode, compound-split, electro-mechanical transmission. The method comprises executing a shift operation from a first to a second operating mode and monitoring shift abort criteria. A revised shift operation is executed to control the transmission shift into a third operating mode effective to meet an operator request for output torque. The exemplary transmission has four fixed gear ratio modes and two continuously variable modes. The preferred shift abort criteria include: monitoring the operator request for output torque; identifying presence of a fault in an oncoming torques transfer device effective to facilitate operation in the second operating mode; monitoring an optimization routine for managing torque inputs from the plurality of torque-generative devices.