The present invention relates to a method for resolving a tooth-on-tooth position of a positive-locking shifting element of an automated manual transmission, in which gear steps of the automated manual transmission are changed by means of a pressure-medium-actuated shift actuator. If, during a change of a gear step of the automated manual transmission, a tooth-on-tooth position occurs at the interlocking shifting element, then the control of the pressure-medium-actuated shift actuator is varied in such manner as to resolve the tooth-on-tooth position. A control unit for carrying out the method is also disclosed.

A method for adapting a biting point pressure of a hydraulically actuated hybrid disengaging clutch arranged in a hybrid drive train of a motor vehicle between an internal combustion engine and an electric machine includes step by step implementation during driving of the motor vehicle via a plurality of selected engagement operations of the hybrid disengaging clutch with a manipulation of a rapid filling routine. Proceeding from an initially stored biting point pressure, a setting pressure, which is reduced relative to a subsequent rapid filling routine, is incrementally increased step by step. An actual value, which is set in each case for a test parameter, is detected until the actual value corresponds to a setpoint value. A change in the transmission of torque of the hybrid disengaging clutch is derivable via the actual value.

Methods and systems for a hydromechanical transmission are provided herein. In one example, a vehicle system is provided that includes a hydromechanical transmission with a power-take off (PTO) that is designed to rotationally couple to an implement. The vehicle system further includes an engine coupled to the hydromechanical transmission and a power-management control unit configured to, during a drive or coast condition, cause the power-management control unit to: determine a net available power for the hydromechanical transmission and manage a power flow between the hydromechanical transmission, a drive axle, and the implement based on the net available power.

A method for operating a power shiftable transmission of a motor vehicle, the transmission including a control unit, an input shaft, an output shaft, a gear set, and multiple shift elements, the method including transmitting, with the control unit, a request for a reduction of a drive torque acting on the input shaft for carrying out an upshift, and determining, with the control unit, whether the reduction is completely possible, partially possible, or impossible based on a signal. When the reduction is completely possible, the method includes controlling, with the control unit, a torque transmission rate of a shift element of the multiple shift elements to be engaged during the upshift according to a first way. When the reduction is partially possible or impossible, the method includes controlling, with the control unit, the torque transmission rate according to a second way, the second way differing from the first way.

Transmissions, control systems for transmissions, and methods of operating transmissions are disclosed. A transmission includes an input shaft, an output shaft, one or more clutches, and a control system. The input shaft is configured to receive rotational power supplied by a drive unit. The output shaft is coupled to the input shaft and configured to provide rotational power supplied to the input shaft to a load. The one or more clutches are coupled between the input shaft and the output shaft to selectively transmit rotational power between the input shaft and the output shaft in one or more operating modes of the transmission. Each of the one or more clutches is selectively engageable in response to one or more fluid pressures applied thereto. The control system is configured to control operation of the one or more clutches to select the one or more operating modes of the transmission.

A method for adapting a biting point pressure of a hydraulically actuated hybrid disengaging clutch arranged in a hybrid drive train of a motor vehicle between an internal combustion engine and an electric machine includes step by step implementation during driving of the motor vehicle via a plurality of selected engagement operations of the hybrid disengaging clutch with a manipulation of a rapid filling routine. Proceeding from an initially stored biting point pressure, a setting pressure, which is reduced relative to a subsequent rapid filling routine, is incrementally increased step by step. An actual value, which is set in each case for a test parameter, is detected until the actual value corresponds to a setpoint value. A change in the transmission of torque of the hybrid disengaging clutch is derivable via the actual value.

A bench test calibration method for generating wet clutch torque transfer functions includes obtaining in-vehicle clutch torques at a set of shift conditions; performing a series of bench tests at various clutch pack clearances and lubrication oil flow rates at the set of shift conditions; adjusting clutch pack clearances and lubrication oil flow rates during the series of bench tests in response to a difference between a bench test measured clutch torques and the corresponding in-vehicle clutch torques exceeding a threshold; and recording relationships between first bench test measured torques and force profiles of a clutch actuator relative to the adjusted clutch pack clearances and lubrication oil flow rates for each of the set of shift conditions as a first transfer function.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying and discharging hydraulic pressure to and from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than that of the first surface. The method includes controlling the friction plates to change from the disengaged state to the engaged state. Controlling the friction plates includes adjusting the hydraulic pressure to a first instruction pressure in a first period in response to a gear shift command, and to a second instruction pressure in a second period.

A method for rocking a vehicle free. The vehicle comprises a drive aggregate (2), a transmission (4), shifting elements (10), and a starting element (5). The rocking free process is carried out as a function of actuation of an accelerator pedal (11) by the driver or a torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal. The shifting element (10) is controlled such that reduced actuation of the accelerator pedal or reduced torque delivered by the drive aggregate (2), reduces a control pressure of the shifting element (10) of the transmission (4) down to a filling pressure or a pressure that corresponds to the filling pressure, and increased actuation of the accelerator pedal or increased torque delivered by the drive aggregate (2), increases the control pressure of the shifting element (10) and the shifting element is operated in a slipping mode.

A control device that controls a vehicle drive transfer device in which a speed change device that includes a plurality of engagement devices and that selectively establishes one of a plurality of shift speeds with different speed ratios in accordance with a state of engagement of the plurality of engagement devices is provided in a power transfer path that connects between a drive force source and wheels.