Abstract: A method for controlling a vehicle driveline uses sensors to estimate a need for powering secondary wheels for each of a plurality of conditions. The estimates are scaled and the scaled estimates summed. Only primary wheels are powered when the summed estimates are less than a reference value. Both the primary and secondary wheels are powered when the summed estimates exceed the reference value.

Abstract: A transfer case and transmission are designed to permit the transmission hydraulic control system to control a range selection coupler and a torque on demand clutch in the transfer case. Two pressure circuits are transmitted from the transmission to the transfer case: a high range circuit and a low range circuit. The low range circuit is pressurized to engage low range while the range circuit is pressurized to engage high range. The torque on demand clutch is controlled by whichever of these circuits has the higher pressure. Lubrication is provided to a front section of the transfer case via the transmission output shaft, with the fluid returning to the transmission sump through a drainback passageway. The rear portion of the transfer case has a segregated sump. A control strategy is employed to partially fill front section of the transfer case with fluid in preparation for vehicle towing.

Abstract: A transfer case and transmission are designed to permit the transmission hydraulic control system to control a range selection coupler and a torque on demand clutch in the transfer case. Two pressure circuits are transmitted from the transmission to the transfer case: a high range circuit and a low range circuit. The low range circuit is pressurized to engage low range while the range circuit is pressurized to engage high range. The torque on demand clutch is controlled by whichever of these circuits has the higher pressure. Lubrication is provided to a front section of the transfer case via the transmission output shaft, with the fluid returning to the transmission sump through a drainback passageway. The rear portion of the transfer case has a segregated sump. A control strategy is employed to partially fill front section of the transfer case with fluid in preparation for vehicle towing.

Abstract: A method for controlling a vehicle driveline uses sensors to estimate a need for powering secondary wheels for each of a plurality of conditions. The estimates are scaled and the scaled estimates summed. Only primary wheels are powered when the summed estimates are less than a reference value. Both the primary and secondary wheels are powered when the summed estimates exceed the reference value.

Abstract: A system and a method for controlling a hybrid vehicle powertrain during a change from a two-wheel drive mode to a four-wheel drive mode is provided. In response to a request to couple the second pair of wheels to the powertrain, a driveline controller commands an increased torque from the electric motor to be applied to the first pair of wheels The increased torque from the electric motor is based on an AWD engagement torque of the second pair of wheels to counteract an engagement torque of a second pair of drive wheels before changing from the two-wheel drive mode to the four-wheel drive mode.

Abstract: A vehicle driveline includes a power source, a transmission connected to the power source and including an output driveably connected to primary road wheels, a driveshaft, a synchronizer that opens and closes a drive connection between the output and the driveshaft, and a clutch that alternately opens and closes a drive connection between the driveshaft and secondary road wheels. A control executes synchronization and connection strategies using one of singular, overlapping and sequential activation of the driveline components that produce all-wheel-drive on-demand.

Abstract: A system and a method for controlling a hybrid vehicle powertrain during a change from a two-wheel drive mode to a four-wheel drive mode is provided. In response to a request to couple the second pair of wheels to the powertrain, a driveline controller commands an increased torque from the electric motor to be applied to the first pair of wheels The increased torque from the electric motor is based on an AWD engagement torque of the second pair of wheels to counteract an engagement torque of a second pair of drive wheels before changing from the two-wheel drive mode to the four-wheel drive mode.

Abstract: A method for controlling a vehicle driveline includes using current conditions to estimate wheel slip probability and vehicle dynamics handling support requirements, producing two-wheel drive operation, if said slip probability and handling support requirement is low and a condition for forced driveline connection is absent, and producing four-wheel drive operation, if said slip probability and/or handling support requirement is high and a condition for forced driveline disconnection is absent.

Abstract: A vehicle driveline includes a power source, a transmission connected to the power source and including an output driveably connected to primary road wheels, a driveshaft, a synchronizer that opens and closes a drive connection between the output and the driveshaft, and a clutch that alternately opens and closes a drive connection between the driveshaft and secondary road wheels. A control executes synchronization and connection strategies using one of singular, overlapping and sequential activation of the driveline components that produce all-wheel-drive on-demand.