A method for operating a transmission device for a motor vehicle. A drive gear is selected from a drive gear set and set on a transmission and upon going above a rotational speed upper limit a drive gear with a larger gearing ratio and upon going below a rotational speed lower limit a drive gear with a smaller gearing ratio is selected from the drive gear set and set on the transmission. In a normal operating mode, the drive gear set corresponds to a normal operation drive gear set having a plurality of different drive gears, and the rotational speed upper limit corresponds to a normal operation rotational speed upper limit and the rotational speed lower limit corresponds to a normal operation rotational speed lower limit. In an alternative operating mode the drive gear set corresponds to an alternative operation drive gear set, having a smaller number of different drive gears than the normal operation drive gear set.

An apparatus for controlling automatic transmission includes: an automatic gear-shift mode for automatically selecting a gear position based on a driving condition of a vehicle; and a manual gear-shift mode for selecting the gear position based on an output of an up-shift instructing unit or a down-shift instructing unit, and sets a predetermined time period for maintaining the manual gear-shift mode when the up-shift instructing means unit is operated, to be shorter than the predetermined time period when the down-shift instructing unit is operated, when the gear position is at or higher than a predetermined gear position.

The invention relates to a method for controlling a hydraulic system of a vehicle driveline. According to the method a transmission (13) of a driveline (2) is controlled in a limited actuation mode, if the pressure (p) is below the predetermined critical lower threshold value (Tel), wherein in the limited actuation mode the transmission (13) is controlled such that less actuator actuations is performed in comparison to a normal actuation mode.

The invention relates to a method for controlling a driveline (10) of a vehicle (1), wherein the driveline (10) at least comprise a clutch (12) and a transmission (13), where the clutch (12) is adapted to connect the transmission to an propulsion unit (11). The method comprises the steps of;—estimating (105) an upcoming clutch temperature at least dependent on an imminent drive route, and if (106) the estimated upcoming clutch temperature is above a threshold value (T);—controlling (107) the driveline (10) in a critical heat mode, wherein in the critical heat mode the transmission (13) is controlled such that a clutch temperature increase is lower in comparison to a normal driveline control mode.

The invention relates to a method for controlling a driveline (10) of a vehicle (1), wherein the driveline (10) at least comprise a clutch (12) and a transmission (13), where the clutch (12) is adapted to connect the transmission to an propulsion unit (11). The method comprises the steps of;—estimating (105) an upcoming clutch temperature at least dependent on an imminent drive route, and if (106) the estimated upcoming clutch temperature is above a threshold value (T);—controlling (107) the driveline (10) in a critical heat mode, wherein in the critical heat mode the transmission (13) is controlled such that a clutch temperature increase is lower in comparison to a normal driveline control mode.

The invention relates to a method for controlling a hydraulic system of a vehicle driveline. According to the method a transmission (13) of a driveline (2) is controlled in a limited actuation mode, if the pressure (p) is below the predetermined critical lower threshold value (Tel), wherein in the limited actuation mode the transmission (13) is controlled such that less actuator actuations is performed in comparison to a normal actuation mode.

In a transmission device, a power roller transmits a rotational driving force from an input disc to an output disc in a transmission ratio (transmission gear ratio) corresponding to a tilt motion angle. The power roller allows the transmission ratio to be changed in such a manner that the position of the trunnion on which the power roller is tiltably supported is changed by a trunnion drive mechanism. Hydraulic oil is supplied from a hydraulic pump to the trunnion drive mechanism via a direction selector valve. The direction selector valve selects a flow direction of the hydraulic oil to supply the hydraulic oil to a speed reduction chamber or a speed increase chamber of the trunnion drive mechanism, and discharge the hydraulic oil from the other. In a case where a discharge condition is met, the controller controls a movement of the discharge valve to discharge the hydraulic oil from the speed increase chamber.

An apparatus for controlling automatic transmission includes: an automatic gear-shift mode for automatically selecting a gear position based on a driving condition of a vehicle; and a manual gear-shift mode for selecting the gear position based on an output of an up-shift instructing unit or a down-shift instructing unit, and sets a predetermined time period for maintaining the manual gear-shift mode when the up-shift instructing unit is operated, to be shorter than the predetermined time period when the down-shift instructing unit is operated, when the gear position is at or higher than a predetermined gear position.

A method for operating a transmission device for a motor vehicle. A drive gear is selected from a drive gear set and set on a transmission and upon going above a rotational speed upper limit a drive gear with a larger gearing ratio and upon going below a rotational speed lower limit a drive gear with a smaller gearing ratio is selected from the drive gear set and set on the transmission. In a normal operating mode, the drive gear set corresponds to a normal operation drive gear set having a plurality of different drive gears, and the rotational speed upper limit corresponds to a normal operation rotational speed upper limit and the rotational speed lower limit corresponds to a normal operation rotational speed lower limit. In an alternative operating mode the drive gear set corresponds to an alternative operation drive gear set, having a smaller number of different drive gears than the normal operation drive gear set.

A hybrid vehicle includes an electronic control unit configured to, when the drive mode is changed from one of the series-parallel mode and the parallel mode to the other one of the series-parallel mode and the parallel mode and the speed stage is changed from one of the low speed stage and the high speed stage to the other one of the low speed stage and the high speed stage, selectively execute either one of a first control and a second control. The first control is control in which the drive mode and the speed stage are changed by passing through the series mode. The second control is control in which one of the drive mode and the speed stage is changed and then the other one of the drive mode and the speed stage is changed without passing through the series mode.