Abstract: A drive torque transfer case is provided. The transfer case includes an input shaft, an output shaft, a gear assembly coupled to the input shaft, and a range clutch assembly coupled to the output shaft. The range clutch assembly includes a clutch member and a multi-piston actuator configured to receive a pressurized transmission fluid for selectively axially translating the clutch member to engage a component of the gear assembly for transmitting a drive torque from the input shaft to the output shaft. The multi-piston actuator includes an internal piston having a first annular surface area A1 and a third annular surface area A3, and an external piston having a second annular surface area A2 and a fourth annular surface area A4. The A1 and A2 are in hydraulic communication with a first hydraulic chamber, and A3 and A4 are in hydraulic communication with a second hydraulic chamber.

Abstract: A drive torque transfer case is provided. The transfer case includes an input shaft, an output shaft, a gear assembly coupled to the input shaft, and a range clutch assembly coupled to the output shaft. The range clutch assembly includes a clutch member and a multi-piston actuator configured to receive a pressurized transmission fluid for selectively axially translating the clutch member to engage a component of the gear assembly for transmitting a drive torque from the input shaft to the output shaft. The multi-piston actuator includes an internal piston having a first annular surface area A1 and a third annular surface area A3, and an external piston having a second annular surface area A2 and a fourth annular surface area A4. The A1 and A2 are in hydraulic communication with a first hydraulic chamber, and A3 and A4 are in hydraulic communication with a second hydraulic chamber.

Abstract: A dual pressure pump system for a transmission includes a dual pressure pump having a first pump outlet and a second pump outlet, and a pressure regulator valve defining a first chamber in fluid communication with the first pump outlet and a second chamber in fluid communication with the second pump outlet. The pressure regulator valve is configured to selectively connect the first chamber with a first pressure line operating at a first greater-than-zero pressure and to selectively connect the second chamber to a second pressure line operating at a second greater-than-zero pressure.

Abstract: A dual pressure pump system for a transmission includes a dual pressure pump having a first pump outlet and a second pump outlet, and a pressure regulator valve defining a first chamber in fluid communication with the first pump outlet and a second chamber in fluid communication with the second pump outlet. The pressure regulator valve is configured to selectively connect the first chamber with a first pressure line operating at a first greater-than-zero pressure and to selectively connect the second chamber to a second pressure line operating at a second greater-than-zero pressure.

Abstract: A variable flow orifice for a hydraulic control system in a transmission includes a shape memory alloy that selectively increases and decreases the size of an orifice. The deformation of the shape memory alloy, and therefore the size of the orifice, is a function of the temperature of the transmission. During cold conditions the orifice size is increased and during normal operating conditions the size of the orifice is decreased.

Abstract: A transmission includes an input member, an output member, a plurality of torque-transmitting mechanisms that are selectively engageable to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member, and one or more latches associated with one or more of the torque-transmitting mechanisms. The one or more latches engages the respective torque-transmitting mechanisms during or prior to a start event.

Abstract: A hybrid-electric vehicle having a continuously variable transmission is provided. The continuously variable transmission further includes a forward disconnect clutch configured to selectively couple and decouple the continuously variable transmission and a first set of drive wheels. The hybrid-electric vehicle further includes a rear e-axle assembly, which allows the vehicle to operate in an electric-only mode, in which the vehicle is propelled with power generated solely by at least one electric power component. When the vehicle is operated in electric-only mode, the transmission disconnect clutch is disengaged, such that the continuously variable transmission is decoupled from the first set of drive wheels to allow the continuously variable transmission to operate in a low loss state. A method of transitioning an all-wheel drive hybrid-electric vehicle between an electric only mode and a hybrid mode, i.e., completing a “flying start,” is also provided.

Abstract: A method of operating a torque converter clutch in an engine start-stop vehicle improves launch after an auto stop event. During the autostop event, hydraulic fluid is supplied to the torque converter clutch operator through one or more solenoid valves by an auxiliary electric pump. When the prime mover is started at the conclusion of the autostop event, the torque converter clutch is thus locked, assuring rapid and sufficient torque transfer through the torque converter to the transmission and improved acceleration during vehicle launch. As the vehicle accelerates, the hydraulic pressure in the clutch operator is reduced and slip through the clutch increased to achieve a smooth launch and return to conventional torque converter operation.

Abstract: A transmission includes an input member, an output member, a plurality of torque-transmitting mechanisms that are selectively engageable to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member, and one or more latches associated with one or more of the torque-transmitting mechanisms. The one or more latches engages the respective torque-transmitting mechanisms during or prior to a start event.

Abstract: A transmission includes an input member, an output member, a plurality of torque-transmitting mechanisms that are selectively engageable to establish at least four forward speed ratios and at least one reverse speed ratio between the input member and the output member, and one or more latches associated with one or more of the torque-transmitting mechanisms. The one or more latches engages the respective torque-transmitting mechanisms during or prior to a start event.

Abstract: A method of operating a torque converter clutch in an engine start-stop vehicle improves launch after an auto stop event. During the autostop event, hydraulic fluid is supplied to the torque converter clutch operator through one or more solenoid valves by an auxiliary electric pump. When the prime mover is started at the conclusion of the autostop event, the torque converter clutch is thus locked, assuring rapid and sufficient torque transfer through the torque converter to the transmission and improved acceleration during vehicle launch. As the vehicle accelerates, the hydraulic pressure in the clutch operator is reduced and slip through the clutch increased to achieve a smooth launch and return to conventional torque converter operation.

Abstract: A hydraulic control system for a dual clutch transmission includes a source of pressurized hydraulic fluid, first and second actuator control devices in downstream fluid communication with the source of pressurized hydraulic fluid, and first and second clutch control devices in downstream fluid communication with the source of pressurized hydraulic fluid. A first valve is in downstream fluid communication with the first and second actuator control devices. A second valve is in downstream fluid communication with the first valve, the first clutch control device and the second clutch control device, and the second valve is moveable between two positions by the first and second clutch control devices. Selective activation of combinations of the control devices allows for a pressurized fluid to engage the dual clutch and an actuator in order to shift the transmission into a desired gear ratio.

Abstract: An automatic transmission includes a control system for controlling a clutch of the transmission. The control system includes a first variable flow solenoid and a second variable flow solenoid, each in selective fluid communication with the clutch. The first variable force solenoid provides hydraulic fluid within a first pressure range of 0 and 1,000 kPa. The second variable force solenoid provides hydraulic fluid within a second pressure range of 0 and 2,000 kPa. A transmission controller sends an electrical signal having a current between the range of 0 and 1 amp to one of the first and second variable flow solenoids. The pressure output of each of the first and second variable force solenoids is a function of, within their respective first and second pressure ranges, the amplitude of the current of the electrical signal to provide two distinct power gains to the single clutch.

Abstract: A transmission includes an input member, an output member, a plurality of torque-transmitting mechanisms that are selectively engageable to establish at least four forward speed ratios and at least one reverse speed ratio between the input member and the output member, and one or more latches associated with one or more of the torque-transmitting mechanisms. The one or more latches engages the respective torque-transmitting mechanisms during or prior to a start event.

Abstract: A hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio.

Abstract: A method for controlling a clutch assembly includes controlling an actual clutch fill pressure using open-loop pressure controls when an active fill phase is detected, and using closed-loop pressure controls when the active fill phase is complete or when an overfill condition is detected. The method supplies the actual clutch pressure according to a second set of open-loop pressure controls when a step in commanded clutch pressure is detected. The method monitors a fill pressure and time during the step, and applies the clutch pressure according to the closed-loop pressure controls when either value equals a corresponding threshold value. A clutch assembly has a piston for compressing clutch disks to initiate a shift event, an algorithm for controlling the shift event, and a sensor for determining an actual clutch pressure during the shift phases. The algorithm switches between closed-loop and open-loop pressure controls in response to different shift phases.

Abstract: A variable flow orifice for a hydraulic control system in a transmission includes a shape memory alloy that selectively increases and decreases the size of an orifice. The deformation of the shape memory alloy, and therefore the size of the orifice, is a function of the temperature of the transmission. During cold conditions the orifice size is increased and during normal operating conditions the size of the orifice is decreased.

Abstract: A method and control system for operating a transmission includes a transmission control module determining a transmission sensor signal and a transmission pressure sensor offset prior to starting a vehicle engine and an engine start initiator starting the vehicle engine. The transmission control module controls a transmission function in response the transmission pressure sensor offset and the pressure sensor signal.

Abstract: A hydraulic control system for a automatic transmission includes a plurality of solenoids and valves in fluid communication with a plurality of shift actuators. The shift actuators are operable to actuate a plurality of torque transmitting devices. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the shift actuators. The solenoids are configured to provide a forward gear ratio and a reverse gear ratio when the solenoids are deengerized.

Abstract: A hydraulic control system for actuating a torque transmitting device in a transmission includes a sump for receiving a hydraulic fluid and a piezoelectric pump for pumping the hydraulic fluid from the sump to the torque transmitting device. A first fluid flow path communicates the hydraulic fluid from the sump to the piezoelectric pump and a second fluid flow path communicates the hydraulic fluid from the piezoelectric pump to the torque transmitting device. An exhaust means selectively communicates the hydraulic fluid from the torque transmitting device to the sump.