Method and control unit for operating a motor vehicle drive train

• Main Authors: Platzer, Falko, Wolfgang, Werner, Jungaberle, Alexander
• Format: Patent
• Language: English
• Published: 22.02.2022
• Subjects: ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS INVEHICLES; ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OFTRANSMISSIONS IN VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GASEXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; PERFORMING OPERATIONS; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TOTHE CONTROL OF A PARTICULAR SUB-UNIT; TRANSPORTING; VEHICLES IN GENERAL

A method for operating a drive train of a motor vehicle may include, for a starting process of an internal combustion engine, transferring the separating clutch from a disengaged condition into an engaged condition or a slip state such that the electric machine accelerates the internal combustion engine to a starting speed. The method may further include actuating a torque-transmitting element between the electric machine and the output shaft to enter a slip state. The method may also include increasing the torque of the electric machine to reliably reach and hold the slip state of the torque-transmitting element. Additionally, the method may include operating the electric machine as a generator or as a motor depending on an expected load direction of the drive train during the starting process to reliably reach and hold the torque-transmitting element in the slip state.