A method of operating an automated transmission control for a powershift transmission having a plurality of powershift gears and a synchronized transmission having a plurality of synchronized gears in the drive-train of a vehicle. The drive-train includes a drive motor, the powershift transmission and the synchronized transmission, with an electronic control unit by which an upshift of the gears of the synchronized transmission and the upshift of the gears of the powershift transmission can be carried out, and to which a motor load signal representing the motor load of the drive motor and a rotational speed signal representing the rotational speed at the output of the drive motor can be sent.

A system for controlling shifting includes an engine, a driven member, and a shiftable transmission including an input shaft coupled to the engine and an output shaft coupled to the driven member. The system further includes a plurality of sensors for monitoring parameters of at least one of the engine, the driven member, or the transmission, a torque converter disposed between the engine and the input shaft, and an electronic control unit including a processor and a memory. The electronic control unit is operable to receive sensed parameters from the plurality of sensors, determine a torque ratio across the torque converter based on the sensed parameters, determine a speed ratio associated with the torque ratio, determine a rotational speed of the input shaft based on the speed ratio and the sensed parameters, and make a shifting decision based on the rotational speed of the input shaft.

A continuously variable transmission (CVT) for a vehicle includes an input member, an output member and a variator assembly including a first pulley rotatably coupled to the input member and a second pulley rotatably coupled to the output. The first and second pulleys are rotatably coupled by a flexible continuous rotatable device. A control system is provided including an instruction set executable to determine an initial variator speed ratio of the variator assembly and detect an event causing a change in an operational state of the vehicle. The control system determines a compensation strategy to adjust the variator speed ratio in response to the change in the operational state of the vehicle and generates an adjusted variator speed ratio based upon the compensation strategy. The control system transmits the adjusted variator speed ratio to the variator assembly.

A control system controls a power transmission system located between a motive power source and drive wheels. The power transmission system includes a fluid coupling and an engagement device. The control system includes an electronic control unit configured to: obtain information concerning vibration of the power transmission system; determine whether the vibration of the power transmission system is in a resonance region of the power transmission system; control the engagement device so that the engagement device slips, when the electronic control unit determines that the power transmission system is in the resonance region; and control the motive power source when the electronic control unit determines that the power transmission system is in the resonance region, so that a rotational speed of the motive power source increases as compared with a case where the power transmission system is not in the resonance region.

A system for controlling shifting includes an engine, a driven member, and a shiftable transmission including an input shaft coupled to the engine and an output shaft coupled to the driven member. The system further includes a plurality of sensors for monitoring parameters of at least one of the engine, the driven member, or the transmission, a torque converter disposed between the engine and the input shaft, and an electronic control unit including a processor and a memory. The electronic control unit is operable to receive sensed parameters from the plurality of sensors, determine a torque ratio across the torque converter based on the sensed parameters, determine a speed ratio associated with the torque ratio, determine a rotational speed of the input shaft based on the speed ratio and the sensed parameters, and make a shifting decision based on the rotational speed of the input shaft.

A tractor is disclosed having an engine fitted with a speed governor, drive wheels, a transmission connecting the engine to the drive wheels, a controller serving to select the effective transmission ratio, and an engine driven power take-off (PTO) shaft for driving ancillary equipment connected to the tractor. When in a part load operating mode in which the PTO shaft is connected to drive an implement and the tractor is moving, the governor is set to maintain the engine working point to follow a selected speed governor line on the speed/load map of the engine. The controller is operative to initiate a change in the transmission ratio when the engine speed cannot be maintained within the specified tolerance of the desired engine speed.