Abstract: A method for controlling a powertrain system in response to a command to execute a multi-state shift event for the transmission includes determining an initial output torque limit and determining an initial commanded output torque based upon the initial output torque limit. The powertrain system is controlled to generate torque in response to the initial commanded output torque prior to completion of a first state transition of the multi-state shift event that includes a commanded torque reduction. After completion of the first state transition of the multi-state shift event that includes the commanded torque reduction, a torque ramp rate is determined, and the initial commanded output torque is adjusted based upon the torque ramp rate. The powertrain system is controlled to generate torque in response to the initial commanded output torque and the adjusted initial commanded output torque during a remainder of the multi-state shift event.

Abstract: A method for controlling a powertrain system in response to a command to execute a multi-state shift event for the transmission includes determining an initial output torque limit and determining an initial commanded output torque based upon the initial output torque limit. The powertrain system is controlled to generate torque in response to the initial commanded output torque prior to completion of a first state transition of the multi-state shift event that includes a commanded torque reduction. After completion of the first state transition of the multi-state shift event that includes the commanded torque reduction, a torque ramp rate is determined, and the initial commanded output torque is adjusted based upon the torque ramp rate. The powertrain system is controlled to generate torque in response to the initial commanded output torque and the adjusted initial commanded output torque during a remainder of the multi-state shift event.

Abstract: A vehicle includes an internal combustion engine coupled to an input member of a multi-mode transmission configured to transfer torque to an output member coupled to a ground wheel with the internal combustion engine in an ON state generating an input torque. A method for controlling the vehicle includes identifying an undesirable operating region including an input/output torque region for operating the multi-mode transmission. In response to an operator request for creep torque, motor torque is controlled from a torque machine coupled to the multi-mode transmission such that the multi-mode transmission is operating outside the undesirable operating region while a mechanical braking torque to the ground wheel is coincidentally controlled in response to an operator-commanded braking, the input torque from the engine, and the motor torque from the torque machine.

Abstract: A method for operating a powertrain through selective application of a hydraulically actuated clutch includes monitoring a state of a pressure control switch operatively coupled the clutch, monitoring a hydraulic line pressure utilized by the pressure control switch to fill the clutch, determining a hydraulic flow rate flowing to the clutch based upon the state of the pressure control switch and the hydraulic line pressure, tracking a clutch fill volume of the clutch based upon the hydraulic flow rate, and controlling operation of the clutch based upon the clutch fill volume.

Abstract: A system and method of controlling a clutch fill command based on the hydraulic state of an oncoming clutch is provided. A vehicle includes a hydraulically-actuated oncoming clutch that is configured to engage during a shift event from one operating mode of the vehicle to another. A controller is configured to generate a clutch fill command at an initial time such that completion of the clutch fill command is synchronized with an identified speed profile of the oncoming clutch. The oncoming clutch defines a real-time hydraulic state when the clutch fill command is generated. The controller is configured to generate a real-time acceptable speed margin for the oncoming clutch based at least partially on the real-time hydraulic state of the oncoming clutch. The controller is configured to cancel the clutch fill command if a real-time speed of the oncoming clutch is outside the generated real-time acceptable speed margin.

Abstract: A method for controlling hydraulic line pressure of a hydraulic control system in transmission includes determining an available flow from a plurality of hydraulic pumps, determining a flow consumption of functions served by the hydraulic control system, determining an estimated hydraulic line pressure based upon the flow from the pumps and the flow consumption, determining a desired hydraulic line pressure, and controlling the hydraulic pumps based upon the desired hydraulic line pressure and the estimated hydraulic line pressure.

Abstract: A method of controlling a fluid pump to supply lubricating fluid to a plurality of fluid requiring components in a hybrid vehicle powertrain includes selecting a component-required flow rate for each respective component using a determined operating speed and torque for that respective component. Once the each component-required flow rate is selected, the system flow rate is set to the maximum component-required flow rate of the plurality of component-required flow rates. The fluid pump is then commanded to supply fluid to each of the plurality of fluid requiring components at the system flow rate.

Abstract: A method of controlling a pump for a hybrid transmission includes commanding a first line pressure of the transmission and deriving a first torque value—an open-loop torque value—from the first line pressure command, and commanding the pump to operate at the first torque value. The method monitors actual speed of the pump and derives a second torque value—a closed-loop torque value—therefrom. A third torque value is derived from the first and second torque values, and the pump commanded to operate at the third torque value. A first speed value may be derived from the first line pressure command, and the second torque value derived from the difference between the monitored and the first speed values. Deriving the third torque value may include a substantially-linear combination of the first and second torque values.

Abstract: A method for operating a powertrain system includes executing a transmission shift between an initial electrically-variable transmission (EVT) range and a target EVT range. The transmission shift includes transitioning to operating with three speed degrees of freedom including controlling speed of a second torque machine to synchronize speed of an oncoming clutch associated with the target EVT range and coincidentally controlling speeds of a first torque machine and an engine to achieve a preferred speed of the output member of the transmission. The transmission shift further includes controlling torque output from the first torque machine in response to an output torque request, and activating the oncoming clutch upon synchronizing the speed of the oncoming clutch. Subsequent to the transmission shift, the powertrain system is operated in the target EVT range.

Abstract: A powertrain includes 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 through selective application of a plurality of clutches. A method for controlling the powertrain includes commanding a shift from a fixed gear operating range state to a second operating range state, commanding decreased reactive torque through an off-going clutch during a torque phase of said commanded shift, and decreasing said reactive torque through said off-going clutch through control of engine input torque.

Abstract: A powertrain system includes an internal combustion engine configured to transfer torque via a clutch to an input member of a hybrid transmission having torque machines configured to transfer torque thereto. Operation of the engine is controlled to facilitate a change in activation of a clutch between the engine and the input member of the hybrid transmission.

Abstract: A vehicle includes an internal combustion engine coupled to an input member of a multi-mode transmission configured to transfer torque to an output member coupled to a ground wheel with the internal combustion engine in an ON state generating an input torque. A method for controlling the vehicle includes identifying an undesirable operating region including an input/output torque region for operating the multi-mode transmission. In response to an operator request for creep torque, motor torque is controlled from a torque machine coupled to the multi-mode transmission such that the multi-mode transmission is operating outside the undesirable operating region while a mechanical braking torque to the ground wheel is coincidentally controlled in response to an operator-commanded braking, the input torque from the engine, and the motor torque from the torque machine.

Abstract: A powertrain system includes an internal combustion engine, a first electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system in the presence of a controlled neutral operation of the electro-mechanical transmission being selected includes monitoring vehicle speed, and only when the monitored vehicle speed is indicative of a low-speed zone restricting a transition from a current engine operating state.

Abstract: A method for controlling a powertrain includes monitoring a desired synchronous transmission shift during deceleration of an output member including a desired operating range state, monitoring an output speed, predicting output deceleration through the desired synchronous transmission shift, determining a penalty cost associated with the desired synchronous transmission shift based upon an input speed profile resulting from the predicted output deceleration and from the desired synchronous transmission shift, and executing the synchronous transmission shift based upon the penalty cost.

Abstract: A hybrid transmission includes first and second electric machines. A method for operating the hybrid transmission in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode includes increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode. Upon deactivation of the off-going clutch, torque outputs of the first and second electric machines and the torque of the oncoming clutch are controlled to synchronize the oncoming clutch. Upon synchronization of the oncoming clutch, the torque for the oncoming clutch is increased and the transmission is operated in the target continuously variable mode.

Abstract: A vehicle includes an engine, a motor, and a gearbox. A clutch is configured to engage to transfer a reactive torque to at least one of the engine, the motor, and the gearbox. The clutch is configured to disengage during a transition from a present operating mode to a target operating mode. A controller is configured to determine an expected slip direction of the clutch, define a non-zero value based at least in part on the expected slip direction, and command the reactive torque to the non-zero value to control the clutch to induce slip during the transition from the present operating mode to the target operating mode.

Abstract: A method for operating a powertrain system includes executing a transmission shift between an initial electrically-variable transmission (EVT) range and a target EVT range. The transmission shift includes transitioning to operating with three speed degrees of freedom including controlling speed of a second torque machine to synchronize speed of an oncoming clutch associated with the target EVT range and coincidentally controlling speeds of a first torque machine and an engine to achieve a preferred speed of the output member of the transmission. The transmission shift further includes controlling torque output from the first torque machine in response to an output torque request, and activating the oncoming clutch upon synchronizing the speed of the oncoming clutch. Subsequent to the transmission shift, the powertrain system is operated in the target EVT range.

Abstract: A method of operating a hybrid powertrain includes commanding an engine start of an engine configured to operate at approximately zero engine speed. A spooling phase includes accelerating the first electric machine with the first machine torque, such that the first electric machine begins rotating. The first machine speed increases in magnitude from zero to non-zero, but engine speed is maintained at approximately zero. The mechanical energy of the rotating first electric machine is stored. A transfer phase includes commanding an increase in magnitude of the first machine torque and decelerating the first electric machine, such that the first machine speed decreases. The stored mechanical energy of the first electric machine is transferred to the engine to increase the engine speed to greater than zero, such that the engine starts.

Abstract: A powertrain system includes an internal combustion engine, a first electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system in the presence of a controlled neutral operation of the electro-mechanical transmission being selected includes monitoring vehicle speed, and only when the monitored vehicle speed is indicative of a low-speed zone restricting a transition from a current engine operating state.

Abstract: A method to monitor a torque transfer device configured to transfer torque within an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and at least one electric machine includes executing a failure detection strategy in response to a detected slip condition of the torque transfer device. The failure detection strategy includes monitoring a magnitude of energy loss of the torque transfer device. A failure condition in the torque transfer device is detected when the magnitude of energy loss achieves a predetermined energy threshold.