Abstract: A vehicle includes a power source configured to provide drive torque, a front axle, a rear axle, and a transfer case configured to distribute drive torque from the power source between the front axle and the rear axle. The vehicle additionally includes a clutch arranged between the front axle and the transfer case. The clutch has a disengaged state and an engaged state drivingly coupling the transfer case and the front axle. The vehicle also includes a regenerative braking system configured to, in response to a braking request, provide regenerative braking torque to the rear axle. The vehicle further includes a controller. The controller is configured to, in response to a braking request and the clutch being in the disengaged state, control the clutch to shift into the engaged state to couple the regenerative braking system to the front axle and provide regenerative braking torque to the front axle.

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 front wheel drive transmission is adapted for all-wheel drive by the addition of a selectively engageable power take-off shaft. When a disconnect clutch is engaged, power may be transferred to rear wheels via a power take-off unit and a rear drive unit to improve vehicle mobility. When the disconnect clutch is disengaged, various components of the all-wheel drive system do not rotate, reducing parasitic losses and improving fuel economy. To provide packaging space for the disconnect clutch, the differential is moved to the left (driver side) of the driven transfer gear. A planetary differential, such as a double pinion planetary differential, is suitable for this location.

Abstract: A vehicle includes a power source configured to provide drive torque, a front axle, a rear axle, and a transfer case configured to distribute drive torque from the power source between the front axle and the rear axle. The vehicle additionally includes a clutch arranged between the front axle and the transfer case. The clutch has a disengaged state and an engaged state drivingly coupling the transfer case and the front axle. The vehicle also includes a regenerative braking system configured to, in response to a braking request, provide regenerative braking torque to the rear axle. The vehicle further includes a controller. The controller is configured to, in response to a braking request and the clutch being in the disengaged state, control the clutch to shift into the engaged state to couple the regenerative braking system to the front axle and provide regenerative braking torque to the front axle.

Abstract: A vehicle includes axle housing, a differential and a ring gear, a scraper port, and a reservoir. The housing has a cover forming a heat exchanger having a coolant side and a lubricant side. The differential and ring gear are configured to pump a lubricating fluid. The scraper port is disposed at a bottom of the heat exchanger adjacent to the ring gear and is configured to direct the lubricating fluid through the lubricant side of the heat exchanger. The reservoir is disposed at a top of the heat exchanger and is configured to receive and store the lubricating fluid from the lubricant side of the heat exchanger.

Abstract: A vehicle includes axle housing, a differential and a ring gear, a scraper port, and a reservoir. The housing has a cover forming a heat exchanger having a coolant side and a lubricant side. The differential and ring gear are configured to pump a lubricating fluid. The scraper port is disposed at a bottom of the heat exchanger adjacent to the ring gear and is configured to direct the lubricating fluid through the lubricant side of the heat exchanger. The reservoir is disposed at a top of the heat exchanger and is configured to receive and store the lubricating fluid from the lubricant side of the heat exchanger.

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 vehicle powertrain includes a transaxle configured to drive front wheels and a power take-off unit configured to drive rear wheels through a driveshaft. The power take-off unit includes a disconnect clutch such that the power flow path to the rear wheels can be disconnected to reduce fuel consumption and reconnected when needed for traction enhancement. Although the disconnect clutch is physically located within the power take-off unit, it is actuated by fluid from the transaxle valve body. The disconnect clutch actuator includes a piston that slides within a chamber in a housing and a solenoid controlled valve that fluidly connects the chamber either to a pressure source or to the transaxle sump.

Abstract: A drive system includes a differential for transmitting power between a power source and first axles; a clutch including a first member driveably connected to the power source and a second member secured to a power transfer shaft; and a servo including a cylinder connected to a pressure source, a piston displaceable in the cylinder for mutually disconnecting the first and second members and allowing mutual engagement of the first and second members.

Abstract: A vehicle powertrain includes a transaxle configured to drive front wheels and a power take-off unit configured to drive rear wheels through a driveshaft. The power take-off unit includes a disconnect clutch such that the power flow path to the rear wheels can be disconnected to reduce fuel consumption and reconnected when needed for traction enhancement. Although the disconnect clutch is physically located within the power take-off unit, it is actuated by fluid from the transaxle valve body. The disconnect clutch actuator includes a piston that slides within a chamber in a housing and a solenoid controlled valve that fluidly connects the chamber either to a pressure source or to the transaxle sump.

Abstract: A front wheel drive transmission is adapted for all-wheel drive by the addition of a selectively engageable power take-off shaft. When a disconnect clutch is engaged, power may be transferred to rear wheels via a power take-off unit and a rear drive unit to improve vehicle mobility. When the disconnect clutch is disengaged, various components of the all-wheel drive system do not rotate, reducing parasitic losses and improving fuel economy. To provide packaging space for the disconnect clutch, the differential is moved to the left (driver side) of the driven transfer gear.

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 system for lubricating a differential mechanism includes a housing containing a ring gear, a pinion meshing with the ring gear, a sump containing fluid, and a reservoir that receives fluid flung from the ring gear as the ring gear rotates through the sump fluid, and an orifice restricting the flow rate of fluid from the reservoir.

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 motor vehicle powertrain includes a multiple speed transmission including a first lube circuit that supplies hydraulic lubricant to components of the transmission, a first oil sump, and a first pump driveably connected to an engine for supplying oil at a first pressure to the lube circuit, a transfer case including a first output, a second oil sump located in the transfer case, a second pump located in the transfer case and driveably connected to the first output, and a check valve for alternately opening and closing a connection between the first pump and the lube circuit and for opening and closing a connection between the second pump and the lube circuit in response to differential pressure between an outlet of the first pump and an outlet of the second pump.

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 drivetrain includes de-energizing a clutch that connects a differential output to a wheel, rotating said component through a sump by pulsing the clutch when a speed of a differential component is less than a reference speed, and cyclically pulsing the clutch while a speed of said component exceeds the reference speed and a count of a timer, started when the clutch is de-energized, exceeds a reference count.

Abstract: A drive system includes a rotating power source, a planetary differential including a ring gear engaged with the power source, a sun gear secured to a first shaft and a carrier secured to a second shaft, a member secured to an output shaft, and a coupler alternately connecting and disconnecting the member and the ring gear.