Abstract: Method for detecting a fault condition in a vehicular hydraulic circuit during a drive cycle using an electric pump includes monitoring an actual pump torque and monitoring a desired pump torque. A current confidence factor is determined based on the actual pump torque and the desired pump torque. An average confidence factor is iteratively calculated based on the current confidence factor and previously determined confidence factors. The average confidence factor is compared to a fault condition threshold. An absence of the fault condition in the hydraulic circuit is detected when the average confidence factor is at least the fault condition threshold, and a presence of the fault condition in the hydraulic circuit is detected when the average confidence factor is less than the fault condition threshold.

Abstract: A powertrain system includes a transmission employing an electrically-powered hydraulic pump providing pressurized hydraulic fluid to a hydraulic circuit. A method of operating the powertrain system includes monitoring a temperature of the hydraulic pump. In response to the temperature exceeding a threshold temperature, power output from an electrically-powered motor coupled to the hydraulic pump is derated, which includes decreasing rotational speed of the hydraulic pump and maintaining hydraulic pressure in the hydraulic circuit.

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 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 transmission includes a plurality of synchronously operated clutches selectably transmitting torque from a torque generative device to an output member. A method to control the transmission through a shift event includes monitoring a desired shift event including monitoring a clutch to be engaged, determining a time at which the clutch to be engaged will be synchronized, determining a required clutch fill time for the clutch to be engaged, and actuating an on-off hydraulic control switch selectably providing pressurized hydraulic fluid to the clutch to be engaged based upon coordinating the time at which the clutch to be engaged will be synchronized and the required clutch fill time.

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 powertrain system includes a transmission employing an electrically-powered hydraulic pump providing pressurized hydraulic fluid to a hydraulic circuit. A method of operating the powertrain system includes monitoring a temperature of the hydraulic pump. In response to the temperature exceeding a threshold temperature, power output from an electrically-powered motor coupled to the hydraulic pump is derated, which includes decreasing rotational speed of the hydraulic pump and maintaining hydraulic pressure in the hydraulic circuit.

Abstract: A transmission fluid pump control system of a vehicle includes a target speed module and a speed control module. The target speed module determines a target speed of an electric transmission fluid pump based on a target output flowrate of the electric transmission fluid pump, a predetermined maximum allowable amount of leakage of transmission fluid pumps, and an efficiency of the electric transmission fluid pump. The speed control module applies power to the electric transmission fluid pump based on the target speed.

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 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 is provided to detect the presence of hydraulic line pressure in a hydraulic control system in an electromechanical transmission. The method includes determining an estimated hydraulic line pressure of the hydraulic control system based upon an input flow and an output flow of hydraulic fluid. The input flow and output flow are regulated with a pressure control device, which is energizable on operator demand. A pressure detection device is fluidly connected to the pressure control device to detect the presence of hydraulic pressure. An override module is applied to the estimated hydraulic line pressure to determine a corrected hydraulic line pressure. The override module sets the corrected hydraulic line pressure to predetermined values based on the operating state indicated by the pressure detection device. The override module corrects for an over-estimation of hydraulic line pressure in operating conditions such as low environmental temperatures.

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 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 adjusting hydraulic line pressure applied to one or more clutch devices in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and at least one electric machine includes predicting a first plurality of powertrain parameters for an upcoming event. For each of a plurality of engine torques, a predicted output torque and a predicted clutch load are determined that minimize a total powertrain operating cost based on an operator torque request and the predicted first plurality of powertrain parameters. Hydraulic line pressure is adjusted based on the engine torque having a lowest powertrain operating cost among the plurality of available engine torques.

Abstract: An example vehicle includes an engine and a motor-generator configured to generate a torque in a first direction. A torque limiter clutch is configured to dissipate a torque in a second direction that opposes the first torque. The torque in the second direction may be caused by a force event. A control processor is configured to detect a possible force event and control the torque limiter clutch in response to detecting the possible force event. A method of controlling the torque limiter clutch includes detecting a possible force event, reducing fluid pressure to the torque limiter clutch in response to detecting the possible force event, confirming the possible force event, maintaining the reduced fluid pressure to the torque limiter clutch if the force event is confirmed, and increasing the fluid pressure to the torque limiter clutch if the force event is not confirmed.

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: Method for detecting a fault condition in a vehicular hydraulic circuit during a drive cycle using an electric pump includes monitoring an actual pump torque and monitoring a desired pump torque. A current confidence factor is determined based on the actual pump torque and the desired pump torque. An average confidence factor is iteratively calculated based on the current confidence factor and previously determined confidence factors. The average confidence factor is compared to a fault condition threshold. An absence of the fault condition in the hydraulic circuit is detected when the average confidence factor is at least the fault condition threshold, and a presence of the fault condition in the hydraulic circuit is detected when the average confidence factor is less than the fault condition threshold.

Abstract: A method for reducing occurrence of clutch slip in electromechanical transmission adapted to selectively transmit mechanical power to an output member through selective application of a hydraulically actuated clutch includes monitoring operation of said clutch, identifying an indication of clutch wear based upon said monitoring said operation, and increasing a minimum clamping force applied to said clutch based upon said indication of clutch wear.

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 powertrain includes an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and first and second electric machines adapted to selectively transmit mechanical power to an output member. An apparatus for controlling the powertrain includes the first and second electric machines, a first electric machine cooling circuit directing a cooling hydraulic flow to the first electric machine, a second electric machine cooling circuit directing a cooling hydraulic flow to the second electric machine, a hydraulic control system receiving a hydraulic flow and selectively channeling the hydraulic flow to the first and second electric machine cooling circuits, and an active electric machine cooling control system monitoring temperatures of the first and second electric machines, monitoring operation of the hydraulic control system, and selectively controlling the hydraulic control system.