A traction drive system for a work machine, including at least one electric motor, a transmission, and a controller. The controller is configured to select a gear ratio of the transmission depending on a change to be expected in a motor output of the at least one electric motor. The change to be expected in the motor output is conditional on a change in the gear ratio of the transmission. The change to be expected in the motor output is determined on the basis of at least one operating parameter of the work machine.

In an automatic transmission control device of the invention configured to start an increase in engagement pressure of a start-up engagement element, when a determination threshold value for determining that a turbine rotational speed has reduced is reached or exceeded, the determination threshold value when a selection operation from a non-traveling range to a traveling range is made before a prescribed period of time from starting of an engine has elapsed, is increased and set greater than the determination threshold value when the selection operation is made after the prescribed period of time has elapsed. Accordingly, a reduction in the turbine rotational speed can be accurately determined, and thus it is possible to suppress torque fluctuations, occurring owing to engagement of a second brake, which is the start-up engagement element.

To curb temperature rises in a control device for a supercharger and extend the life of the control device for the supercharger, a work vehicle includes a variable geometry supercharger with variable boost pressure, and a working device driven by pressure oil discharged from a working hydraulic pump, the work vehicle further including: a supercharger control device adapted to control the supercharger; a temperature detection device adapted to detect temperature of the supercharger control device; and a main control device adapted to limit at least one of maximum rotational speed of an engine and maximum vehicle speed of the work vehicle in case the temperature of the supercharger control device is above a predetermined temperature as compared to case the temperature of the supercharger control device is below the predetermined temperature.

To curb temperature rises in a control device for a supercharger and extend the life of the control device for the supercharger, a work vehicle includes a variable geometry supercharger with variable boost pressure, and a working device driven by pressure oil discharged from a working hydraulic pump, the work vehicle further including: a supercharger control device adapted to control the supercharger; a temperature detection device adapted to detect temperature of the supercharger control device; and a main control device adapted to limit at least one of maximum rotational speed of an engine and maximum vehicle speed of the work vehicle in case the temperature of the supercharger control device is above a predetermined temperature as compared to case the temperature of the supercharger control device is below the predetermined temperature.

At least one electric motor is employed for propelling an electric or hybrid vehicle with a shiftable transmission. Upon reaching a shift threshold, a shift operation is performed in the transmission of the vehicle, wherein a value specifying the shift threshold is varied depending on at least one parameter. As the at least one parameter, a speed is used, at which a power provided by the at least one electric motor for propelling the vehicle has a maximum.

At least one electric motor is employed for propelling an electric or hybrid vehicle with a shiftable transmission. Upon reaching a shift threshold, a shift operation is performed in the transmission of the vehicle, wherein a value specifying the shift threshold is varied depending on at least one parameter. As the at least one parameter, a speed is used, at which a power provided by the at least one electric motor for propelling the vehicle has a maximum.

A vehicle powertrain includes a propulsion unit having a propulsion unit auxiliary brake, a transmission, driven wheels and a control unit arranged to control at least the transmission, where the propulsion unit is drivingly connected to the driven wheels via a clutch and different engagable gear ratios in the transmission. The control unit is arranged to perform the following steps when upshifting: automatically disengage the clutch in order to disengage the propulsion unit from the transmission; upshift the transmission to a new gear compared to current gear; initiate a synchronization in order to decrease and synchronize rotational speed of the propulsion unit to rotational speed of the new gear to be engaged; if it is determined by the control unit that the synchronization cannot be performed by decreasing rotational speed of the propulsion unit by the control unit controlling the auxiliary brake to brake the rotational speed of the propulsion unit then, automatically initiate a reengagement of the clutch in order to perform the synchronization.

A corresponding method, a computer program, a computer readable medium, and a control unit for controlling the powertrain are also provided.

When the speed ratio of a belt-type continuously variable transmission is equal to or larger than a predetermined threshold value, switching between a first power transmission path including a gear transmission mechanism and a second power transmission path including a belt-type continuously variable transmission is performed by means of clutches, so as to reduce a difference in an input shaft rotational speed applied to the clutches before and after the switching.

A vehicle includes a transmission having a first neutral with a first combination of engaged clutches and a second neutral with a second combination of engaged clutches. The second neutral has more engaged clutches than the first neutral. A vehicle controller is programmed to, in response to a request to shift from the first to the second neutral and a failed-on clutch being detected, inhibit the shift to remain in the first neutral.

A vehicle includes a transmission having a first neutral with a first combination of engaged clutches and a second neutral with a second combination of engaged clutches. The first neutral has more engaged clutches than the second. A controller is programmed to, in response to a request to shift from a drive gear to the first neutral and a clutch of the drive gear being failed-on, shift to the second neutral.