Patent ID: 7770676

Claim:
A method for operating a parallel hybrid powertrain ( 1 ) of a vehicle to minimize torque fluctuations in an output of the powertrain caused by starting a combustion engine, the parallel hybrid powertrain comprising at least one internal combustion engine ( 2 ) and at least one electric motor ( 3 ), the electric motor ( 3 ) being located in the powertrain between the internal combustion engine ( 2 ) and the output of the powertrain ( 1 ), a frictionally engaged shifting element ( 5 ) being located between the internal combustion engine ( 2 ) and the electric motor ( 3 ), a starting element ( 6 ), comprising a hydrodynamic torque converter ( 6 A) and a converter lock-up clutch ( 6 B), being located between the electric motor ( 3 ) and the output, and a target output torque (m_fahr_soll) directed to the output being dependent on slippage of the starting element ( 6 ), the method comprising the steps of: generating an input torque with the electric motor ( 3 ); and directing an amount of the input torque to the combustion engine ( 2 ) for starting the internal combustion engine ( 2 ); during a starting phase in which the electric motor ( 3 ) starts the internal combustion engine ( 2 ); directing at least a first portion of the input torque to the torque converter ( 6 A); directing at least a second portion of the input torque to the converter lock-up clutch ( 6 B); and regulating slippage of the starting element ( 6 ) depending on a target input speed (n_ 3 _soll) of the electric motor ( 3 ) and a target transmission capacity (m_WK_soll) of the converter lock-up clutch ( 6 B).