Patent ID: 6886337

Claim:
A method for operating a drive unit of a vehicle, the vehicle including an internal combustion engine having a crankshaft, an exhaust line, an exhaust gas turbine coupled to the exhaust line downstream from the internal combustion engine and operable to be acted upon by the exhaust line, a hydrodynamic unit coupled to the exhaust gas turbine and to the crankshaft, the hydrodynamic unit including freely rotatable rotor-turbine blade assemblies arranged within a working space, the method comprising the steps of: in a traction mode, operating the hydrodynamic unit as a hydrodynamic clutch so that the exhaust gas turbine transmits a positive torque to the crankshaft via the hydrodynamic unit; and in a braking mode, operating the hydrodynamic unit as a retarder to retard rotation of the crankshaft by braking one of the freely rotatable turbine blades of the hydrodynamic unit.