Patent attributes
A method for operating a drive train of a motor vehicle, where the drive train includes a drive aggregate, a group transmission connected between the drive aggregate and a drive output, and a separating cutch connected between the drive aggregate and the group transmission. If a speed is lower than a limit value, the separating clutch is opened and for transmission preselection one or all the other sub-transmission(s) is/are changed to a friction-force-locking condition. The separating clutch is then at least partially closed and the drive aggregate is brought to a defined rotation speed. When a friction-force-locking group transmission is required, it is checked whether a starting gearshift or a driver-desired shift for the group transmission is called for and the target rotation speed of the drive aggregate is checked. Depending on the results, the sub-transmission can be synchronized by a transmission brake or by the drive aggregate.
