Abstract: A hybrid electric vehicle has a controller, an engine, a traction motor, and a transmission. The controller is configured for calculating, using a costing function, the total system losses incurred at each operating point of the HEV, including the losses for each of the engine, the traction motor, and the transmission. The controller selectively modifies the calculated cost of at least one of the engine, the traction motor, and the transmission in a designated one of the transmission states as a function of transmission fluid temperature. An optimal transmission state is then selected as the state having the optimal cost relative to the other transmission states. Selectively modifying the calculated cost may include penalizing the cost of using designated transmission states when the measured fluid temperature exceeds certain calibrated temperature limits. Designated operating states may be disabled above an upper temperature limit to protect the transmission from overheating.

Abstract: A hybrid powertrain includes an engine and electric motors configured to transfer torque through a transmission. A method for controlling the hybrid powertrain includes determining a transition window associated with torque output of one of the electric motors coupled to an element of the transmission. A noise reduction control scheme is executed when the torque output of the one of the electric motors coupled to the element of the transmission is within the transition window.

Abstract: A hybrid powertrain includes and internal combustion engine, an energy storage device, an electro-mechanical transmission having at least one electric machine rotatably coupled to the engine. The electro-mechanical transmission is selectively controllably operative to transmit torque among the engine and the at least one electric machine. A method to start operation of the internal combustion engine includes initiating rotation of a crankshaft of the engine with the at least one electric machine until a first predetermined crankshaft speed is achieved, firing the engine while controlling engine speed with the at least one electric machine until a flare threshold occurs, controlling the engine speed without any interaction from the at least one electric machine based on controlling combustion parameters of the engine, and when a predetermined condition occurs, controlling the engine speed with the at least one electric machine while the engine is still firing.

Abstract: A method to control a powertrain including a transmission, an engine, and an electric machine includes monitoring a desired transmission shift including an oncoming clutch, monitoring operational parameters of the powertrain, monitoring a maximum electric machine torque capacity, determining a desired output torque profile through the desired transmission shift, determining a maximum electric machine torque capability profile through the desired transmission shift based upon the maximum electric machine torque capacity and the operational parameters, comparing the desired output torque profile to the maximum electric machine torque capability profile, determining a preferred oncoming clutch torque profile through the desired transmission shift based upon the comparing, and executing a clutch assisted shift based upon the preferred oncoming clutch torque profile.

Abstract: A fluid system includes a fluidic device, an electrically-actuated fluid pump having a pump motor, and a control system. The control system controls a speed of the pump using a commanded torque value, and calculates a feedforward torque term as a function of a set of operating values, including a desired fluid line pressure. The control system determines the speed control torque term using pump speed error, and adds the feedforward torque term to the speed control torque term to calculate the commanded torque value. The speed control torque term may be determined using an integral term of a proportional integral derivative (PID) portion of the control system. A method for controlling pump speed includes calculating the feedforward torque term, determining the speed control torque term using a pump speed error, and adding the feedforward torque term to the speed control torque term to calculate the commanded torque value.

Abstract: Improved methods for executing a clutch-to-clutch quasi-asynchronous shift in a hybrid transmission, and a hybrid transmission using the same, are presented herein. The method includes: pre-filling the on-coming clutch; determining if the shift is completed using the on-coming or off-going clutch; slipping the off-going clutch first if the shift operation uses the off-going clutch; determining on-coming clutch slip speed and acceleration profiles; determining if the on-coming clutch is filled and whether the slip sign is correct; if using the off-going clutch, locking the on-coming clutch and exhausting the off-going clutch if the on-coming clutch is filled and the slip sign is correct; if using the on-coming clutch, determining whether the on-coming clutch slip is less than a slip threshold and exhausting the off-going clutch if the on-coming clutch is filled and the slip sign is correct; and locking the on-coming clutch if the slip is less than the slip threshold.

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 method for controlling an electromechanical transmission includes monitoring a current hydraulic circuit oil temperature, monitoring a current state of flow management valves, monitoring a command for cooling of electric machines, monitoring a desired transmission operating range state, utilizing a state machine to determine a sequence for controlling positions of the flow management valves to achieve the desired transmission operating range state based upon the monitored properties.

Abstract: A starting system for an internal combustion engine includes a starter motor configured to transfer torque to the engine during an engine starting event, a low-voltage power bus including a first bus segment and a second bus segment, a controllable isolation circuit including a first state wherein the first and second bus segments are electrically coupled and a second state wherein the first and second bus segments are electrically isolated, a low-voltage battery and the starter motor electrically coupled to the first bus segment, an accessory power module and a power supply for a control module electrically coupled to the second bus segment; and the control module configured to control the isolation circuit to the second state to electrically isolate the first bus segment from the second bus segment during the engine starting event.

Abstract: A vehicular powertrain includes an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine. A method for operating the powertrain includes monitoring operator inputs, monitoring a transmission output, and terminating an engine operating mode when a time-rate change in the transmission output exceeds a threshold absent a change in the monitored operator inputs.

Abstract: A vehicle includes an engine, a first motor, a second motor, and a gearbox. An oncoming clutch is configured to engage during a transition to a target operating mode to transfer an engine torque to the gearbox during the target operating mode. An off-going clutch is configured to transfer a reactive torque to the gearbox during the transition to the target operating mode. The off-going clutch is configured to be disengaged during at least a portion of the target operating mode. A controller is configured to simultaneously control the off-going clutch and the oncoming clutch during the transition. The controller is configured to control the reactive torque of the off-going clutch using a clutch torque profile associate with the target operating mode and the engagement of the oncoming clutch using a shift profile associated with target operating mode.

Abstract: A system for robust fault detection in an electrically variable, hydraulically controlled transmission includes independently monitoring hydraulic pressure within a hydraulic control circuit and electric machine rotation for detecting clutch state faults.

Abstract: A transmission includes two blocking valves that control fluid pressure to a plurality of clutches. The blocking valves are characterized by a plurality of states that result in at least three transmission operating conditions. Each of the three operating conditions is characterized by fluid pressure being unavailable to a respective one of the plurality of clutches.

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 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 to control a powertrain including a transmission, an engine, and an electric machine includes applying through a series of clutch fill events a series of incrementally changing command pressures in a pressure control solenoid controllably connected to a clutch within the transmission, monitoring a pressure switch fluidly connected to the pressure control solenoid and configured to indicate when the pressure switch is in a full feed state, determining changes in cycle times of the pressure switch corresponding to sequential applications of the series of incrementally changing command pressures, selecting a preferred command pressure to achieve a transient state in the clutch based upon the changes in pressure switch cycle times, and controlling the clutch based upon the preferred command pressure.

Abstract: Control of operation of a hybrid powertrain is provided, wherein mechanical power flow to an output is controlled through selective actuation of torque-transfer clutches. Electric machines are coupled to an energy storage system for electric power flow. The electro-mechanical transmission is operated in a continuously variable operating range state, and, operation of the transmission is monitored. Absence of a mismatch between the commanded continuously variable operating range state and an actual operating state of the transmission is determined. Presence of a mismatch between the commanded operating range state and the actual operating state of the transmission may be determined. Operation of the powertrain is modified when a mismatch between the commanded operating range state and the actual operating state of the transmission is detected.

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.