Methods and systems are provided for a powertrain. In one example, a method for a powertrain includes adjusting a coupling between a synchronization shaft and one or more of an input shaft and an output shaft in response to a clutch drag torque. The adjusting is based on speeds of one or more of the input shaft, the synchronization shaft, and the output shaft.

Disclosed is a torque-converting or speed-converting variable-speed transmission with at least two gear ratios. Each gear ratios is assigned at least one changeable gear pair. Shifting elements act on sliding sleeves (24) connected to the gear pairs to change these gear pairs. The shifting elements are in engagement with a shift drum (10), which is moveable into defined angular positions and rotatable between these angular positions. The shift drum (10) has an electric-motor direct drive (12), which can rotate it and bring it into the particular defined angular positions. A method used to control such a torque-converting or speed-converting variable-speed transmission is also contemplated.

The invention provides an engagement method for engaging a first gear element with a second gear element, at least the second gear element being mounted to move between a meshing position and a disengaged position by means of an actuator. The engagement method including a step of driving at least one of the gear elements in rotation so as to establish a non-zero difference in speed of rotation between said gear elements, and a step of controlling the actuator to perform the following in succession: moving at least the second gear element towards the meshing position; on detecting contact between the gear elements, stopping the movement of the second gear element; and on detecting an ideal angular position for engaging said gear elements, moving the second gear element as quickly as possible into the meshing position.

A shift range control device includes an angle calculation unit, a target angle setting unit, a learning unit and a drive control unit. The learning unit learns a correction value to be used in calculating a motor angle target value based on a motor angle and an output shaft signal. The learning unit learns the correction value based on at least a first change point value, which is the motor angle at a timing at which the output shaft signal changes when a rotation member rotates in a first direction from a state in which an engagement member is in the center of valley section, and/or a second change point value, which is the motor angle at a timing at which the output shaft signal changes when the rotation member rotates in a second direction from a state in which the engagement member is in the center of the valley section.

In a method for controlling a multi-clutch transmission of a vehicle, wherein the multi-clutch transmission is adapted to be shifted either with a power shift or a power cut shift dependent on predetermined vehicle variables, a power shift to a higher gear in low range gear is detected, and, when the power shift to a higher gear in low range gear has been detected, a previously set gear shift strategy is overruled and the multi-clutch transmission is controlled such that a forthcoming gear shift is performed as a power shift.

At least some implementations of a transmission gear shifter include a shifter for a vehicle transmission that includes a first shift member, a retainer, an actuator and a second shift member. The first shift member has a body rotatable about an axis among multiple positions, and the retainer is movable relative to the body between a first position in which the retainer prevents movement of the body and a second position in which the retainer permits movement of the body. The actuator is coupled to the retainer to drive the retainer between the first position and second position. The second shift member is coupled to the retainer for movement with the retainer relative to the body, and arranged to selectively engage and rotate the body.

A method for synchronizing a first drive element rotatable about an axis of rotation with a second drive element rotating about the axis of rotation at a target speed, of a powertrain of a motor vehicle, in which a synchronizing force is exerted on a synchronizing unit by an actuator. A speed, at which the first drive element rotates about the axis of rotation is adapted by the synchronizing unit to the target speed. The synchronizing force is increased during a first time span, so that the speed approaches the target speed. The synchronizing force is continuously reduced during a second time span following the first time span, before the speed corresponds to the target speed.

A power transferring gearset includes a gear synchronization controller disposed in communication with a drive gear, a driven gear and a shifting mechanism. In response to detecting a gear engagement command, the gear synchronization controller is configured to determine a rotational speed delta between a rotational speed of the drive gear and a rotational speed of the driven gear and compare the rotational speed delta to a pre-determined speed delta. In response to determining that the rotational speed delta is less than the predetermined speed delta, the gear synchronization controller applies a rotational shutter function to the drive gear to apply a series of clockwise and counterclockwise rotational cycles to the drive gear simultaneously during the axial movement of the shifting mechanism for preventing a blocked condition of the power transferring gearset while establishing the meshed relationship between the shifting and gear teeth.

A shift range control apparatus switches shift range by controlling the drive of a motor. The shift range control apparatus includes a feedback controller that is configured to perform position feedback control based on a target angle determined corresponding to the request shift range and the actual angle of the motor; a stationary phase energization controller that is configured to perform stationary phase energization control that energizes a stationary phase selected corresponding to an actual angle; and a switching controller that switches between motor control states. The switching controller switches the control state to position feedback control when the request shift range is switched. When the difference between the target angle and the actual angle becomes equal to or less than an angle determination threshold value, the switching controller switches the control state from position feedback control to the stationary phase energization control.

In a case where an operation to a non-parking operation position is performed at the time when an engine stops at a parking position, an electronic control unit executes two controls, i.e., a change to a non-parking position and starting of the engine, simultaneously. At this time, in a case where the operation to the non-parking operation position is performed at the time when the engine is stopped at the parking position by stop-start system, a deceleration start timing of an electric actuator is made earlier in comparison with a case where the operation is performed at a time different from the above. Accordingly, even in a state where a voltage of the electric actuator is decreased, a motor rotation position can be easily stopped at a non-p target rotation position.