| 摘要 |
The disclosure concerns a vehicle powertrain (10) comprising a propulsion unit (11) having a propulsion unit auxiliary brake (25), a transmission (20), driven wheels (4) and a control unit (40) arranged to control at least the transmission (20), where the propulsion unit (11) is drivingly connected to the driven wheels via a clutch (22) and different engagable gear ratios (32, 37, 34, 38) in the transmission. The control unit is arranged to perform the following steps when upshifting: -automatically disengage the clutch (22) in order to disengage the propulsion unit (11) from the transmission (20); -upshift the transmission to a new gear (34, 38) compared to current gear (32, 37); - 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. The disclosure also concerns a corresponding method, a computer program, a computer readable medium, and a control unit (40) for controlling the powertrain. |
