Method and control device for operating a drive train

A method for operating a drive train of a motor vehicle, drive train comprising a drive aggregate (1), a drive output, an automated group transmission (2) connected between the drive aggregate (1) and the drive output (3), and a disconnect clutch (5) connected between the drive aggregate (1) and the group transmission (2), wherein the group transmission (2) comprises a plurality of sub-transmissions that include at least one of (i) a main transmission (9) and a splitter group (10) drivingly connected upstream from the main transmission (9) and (ii) a range group (11) drivingly connected downstream from the main transmission (9), wherein when the disconnect clutch (5) cannot be used to carry out a shifting operation in the group transmission (2), namely it cannot be shifted, an emergency shifting program is activated,

• closing the disconnect clutch (5);
• and
• shifting automatically, according to an emergency shifting program, from a current gear to a target gear of the group transmission, wherein the emergency shifting program is performed as a function of an input rotation speed of the group transmission (2) or as a function of a rotation speed of the drive aggregate (1);
• wherein the main transmission (9) and/or the range group (11) participate exclusively in the shifting.

A control unit configured for operating a drive train of a motor vehicle, wherein:

• the drive train comprises a drive aggregate (1), a drive output (3), an automated group transmission (2) connected between the drive aggregate (1) and the drive output (3), and a disconnect clutch (5) connected between the drive aggregate (1) and the group transmission (2), wherein the group transmission (2) comprises a plurality of sub-transmissions that include a main transmission (9) and a splitter group (10) drivingly connected upstream from the main transmission (9), and a range group (11) drivingly connected downstream from the main transmission (9);
• the disconnect clutch (5) cannot be shifted to carry out a shifting operation in the group transmission (2);
• and
• the control unit is configured to activate an emergency shifting program, wherein gearshifts from a current gear of the group transmission (2) to a target gear of the group transmission (2) are carried out automatically by the control unit as a function of a rotation speed of the drive aggregate (1) with the disconnect clutch (5) closed, with the exclusive participation of the main transmission (9) and/or the range group (11), and without participation of the splitter group (10).