Abstract: A multi-mode transmission includes a plurality of torque transfer clutches fluidly coupled to a hydraulic circuit fluidly coupled to an independently controllable hydraulic pump. Upon detecting an un-commanded activation of one of the torque transfer clutches, operation of the hydraulic pump is disabled, allowable transmission states are identified, and the one of the torque transfer clutches is synchronized. The hydraulic pump is subsequently enabled and the transmission is operated in one of the allowable transmission states.

Abstract: A vehicle includes an engine, a first motor, and a second motor, each configured to generate a torque. A gearbox is configured to receive the generated torque. An oncoming clutch is configured to engage during a transition from a present operating mode to a target operating mode. A controller is configured to identify a speed profile associated with a transition to the target operating mode. The speed profile defines a calibrated profile time that represents an amount of time to synchronize the oncoming clutch during the transition from the present operating mode to the target operating mode. The controller is configured to adjust the calibrated profile time in real time to define an adjusted profile time and control the engagement of the oncoming clutch during the transition from the present operating mode to the target operating mode based at least in part on the adjusted profile time.

Abstract: A vehicle includes a powertrain with an engine, first and second torque machines, and a hybrid transmission. A method for operating the vehicle includes operating the engine in an unfueled state, releasing an off-going clutch which when engaged effects operation of the hybrid transmission in a first continuously variable mode, and applying a friction braking torque to a wheel of the vehicle to compensate for an increase in an output torque of the hybrid transmission resulting from releasing the off-going clutch. Subsequent to releasing the off-going clutch, an oncoming clutch which when engaged effects operation of the hybrid transmission in a second continuously variable mode is synchronized. Subsequent to synchronization of the oncoming clutch, the oncoming clutch is engaged.

Abstract: A method for activating an oncoming clutch in a transmission includes monitoring rotational speeds of clutch elements of the oncoming clutch wherein the clutch elements are coupled to first and second rotationally independent torque actuators. A control speed profile for the first rotationally independent torque actuator is commanded. A speed profile of the oncoming clutch approaching zero speed is generated as is a control speed profile for the second rotationally independent torque actuator corresponding to a speed of the first rotationally independent torque actuator, the speed profile of the oncoming clutch, and an output speed of the transmission. A speed of the second rotationally independent torque actuator is controlled using the control speed profile for the second rotationally independent torque actuator. A speed of the oncoming clutch is monitored and the oncoming clutch is activated when the speed of the oncoming clutch is zero.

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 method to shift a powertrain system from a first operating mode to a second operating mode wherein a common clutch is activated to effect operation in both the first and second operating modes includes, in sequence, deactivating the common clutch, activating an oncoming clutch associated with the second operating mode and deactivating an off-going clutch associated with the first operating mode, and activating the common clutch.

Abstract: A method to execute a shift in a powertrain including a plurality of torque generative devices rotatably connected through a first clutch includes operating the powertrain in a continuously variable operating range state, and monitoring a command to execute the shift including monitoring a target speed for a first torque generative device, and monitoring a command to disengage the first clutch. The first clutch is shifted from an engaged state to a disengaged state, including operating a torque phase of the first clutch wherein the first clutch is transitioned from the engaged state to the disengaged state, and simultaneous with the torque phase, operating an inertia speed phase of the first clutch wherein a speed of the first torque generative device is transitioned from an initial speed to the target speed.

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 system for a vehicle includes a constraint module that generates a plurality of constraints. An output torque module generates a commanded output torque based on a torque request and the plurality of constraints. A split torque module determines a first torque and a second torque to be applied to a transmission of the vehicle based on the plurality of constraints and the commanded output torque. A first one of the plurality of constraints corresponding to a first clutch is adjusted from a first range of values to a second range of values that is different from the first range of values in response to a command to offload the first clutch.

Abstract: A method includes receiving speed constraints associated with two independent vehicle components and receiving speed constraints associated with a first dependent vehicle component and a second dependent vehicle component. The method further includes defining a relationship between the received speed constraints of the independent vehicle components and the first and second dependent vehicle components. Moreover, speed values of an unknown speed constraint associated with a third dependent component are derived based on the defined relationship between the received speed constraints of the independent vehicle components and the first and second dependent vehicle components.

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 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 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 system includes a friction element having a driving mechanism and a driven mechanism. At least one of the driving mechanism and the driven mechanism is configured to rotate. A drive unit is configured to provide a torque to at least one of the driving mechanism and the driven mechanism. A control processor is configured to diagnose a friction element failure based on a slip speed, which is the difference between rotational speeds of the driving mechanism and the driven mechanism. The control processor is further configured to induce a slip condition as part of a shift process and diagnose the friction element failure if the derived slip speed is substantially zero after inducing the slip condition.

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 controlling a powertrain system including a transmission mechanically coupled to an engine and an electric machine includes monitoring operator inputs to an accelerator pedal, determining a preferred operating point of the powertrain based upon the operator inputs, determining a preferred operating range state of the transmission based upon the preferred operating point, determining lead control signals for the engine and the transmission based upon the preferred operating point and the preferred operating range state of the transmission, determining immediate control signals for the electric machine and the transmission, controlling operation of the engine based upon the lead control signals for the engine and the transmission, and controlling operation of the electric machine based upon the immediate control signals for the electric machine and the transmission.

Abstract: A vehicle includes an engine, a first motor, and a second motor, each configured to generate a torque. A gearbox is configured to receive the generated torque. An oncoming clutch is configured to engage during a transition from a present operating mode to a target operating mode. A controller is configured to identify a speed profile associated with a transition to the target operating mode. The speed profile defines a calibrated profile time that represents an amount of time to synchronize the oncoming clutch during the transition from the present operating mode to the target operating mode. The controller is configured to adjust the calibrated profile time in real time to define an adjusted profile time and control the engagement of the oncoming clutch during the transition from the present operating mode to the target operating mode based at least in part on the adjusted profile time.

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. A method for controlling the powertrain includes operating the transmission in an operating range state wherein input speed can operate independent of output speed and wherein a reactive torque is transmitted through the transmission. The method further includes monitoring commands affecting a requested output torque, monitoring a calculated output torque, and prioritizing between an input acceleration of the transmission and an output torque of the transmission based upon whether operating the transmission in the operating range state is in transient operation or stable operation.

Abstract: A method for controlling hydraulic line pressure of a hydraulic control system in 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 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 of clutch control includes engaging a first holding clutch to place the transmission in a first neutral mode and predicting a first EVT mode. The method begins tracking a first output clutch and predicts a second EVT mode. Tracking the first output clutch ends and tracking a second holding clutch begins. The method engages the second holding clutch to place the transmission in a second neutral mode, ending tracking of the second holding clutch. The first holding clutch is disengaged to place the transmission in a third neutral mode and the method begins tracking a second output clutch. Engaging the second output clutch places the transmission in the second EVT mode and ends tracking of the second output clutch. The engine may be placed into a speed control mode and the transmission placed into a full hydraulic neutral mode.