Abstract: A hydraulic piston position determination system for a vehicle includes a hydraulic piston actuator configured to move a piston member in response to a hydraulic fluid pressure to engage/disengage a friction member, a hydraulic solenoid valve configured to control the hydraulic fluid pressure at the hydraulic piston actuator by regulating a flow of hydraulic fluid from a hydraulic fluid supply system, and a controller configured to control the hydraulic piston actuator by controlling the hydraulic solenoid valve according to an actual duty cycle based on a flow demand change associated with the hydraulic piston actuator, and determine a position of the hydraulic piston actuator based on (i) a magnetic reluctance change and (ii) a difference between the actual duty cycle and a steady-state duty cycle for the hydraulic solenoid valve.

Abstract: A transmission control system and method involve receiving, by a controller and from a turbine shaft speed sensor, a rotational speed of a turbine shaft of an automatic transmission, receiving, by the controller and from an output shaft speed sensor, a plurality of rotational speeds of an output shaft of the transmission, determining, by the controller, a shift time modifier based on the turbine shaft speed and a gradient of the output shaft speed, modifying, by the controller, a shift time for a pedal-off downshift of the transmission based on the shift time modifier to obtain a modified shift time, and controlling, by the controller, the pedal-off downshift of the transmission based on the modified shift time.

Abstract: A transmission control system and method involve receiving, by a controller and from a turbine shaft speed sensor, a rotational speed of a turbine shaft of an automatic transmission, receiving, by the controller and from an output shaft speed sensor, a plurality of rotational speeds of an output shaft of the transmission, determining, by the controller, a shift time modifier based on the turbine shaft speed and a gradient of the output shaft speed, modifying, by the controller, a shift time for a pedal-off downshift of the transmission based on the shift time modifier to obtain a modified shift time, and controlling, by the controller, the pedal-off downshift of the transmission based on the modified shift time.

Abstract: A system and method for controlling torque includes a first torque transmitting mechanism and a second torque transmitting mechanism. The first torque transmitting mechanism is engageable to achieve a first gear ratio of the transmission. The second torque transmitting mechanism has an apply chamber that is pressurized at a first pressure level to achieve a first engaged position and is pressurized at a second pressure level to achieve a second engaged position. The first pressure level is less than the second pressure level and the second engaged position achieves a second gear ratio of the transmission. A controller is in communication with the first and second torque transmitting mechanisms. The controller includes a control logic for pressurizing the apply chamber of the second torque transmitting mechanism to the first pressure level if the first operating condition has exceeded a threshold operating condition.

Abstract: A system and method for controlling torque includes a first torque transmitting mechanism and a second torque transmitting mechanism. The first torque transmitting mechanism is engageable to achieve a first gear ratio of the transmission. The second torque transmitting mechanism has an apply chamber that is pressurized at a first pressure level to achieve a first engaged position and is pressurized at a second pressure level to achieve a second engaged position. The first pressure level is less than the second pressure level and the second engaged position achieves a second gear ratio of the transmission. A controller is in communication with the first and second torque transmitting mechanisms. The controller includes a control logic for pressurizing the apply chamber of the second torque transmitting mechanism to the first pressure level if the first operating condition has exceeded a threshold operating condition.