Method and apparatus for controlling operation of a hybrid powertrain during a key-on crank start event

• Main Authors: SCHWENKE TRAVIS R, SMITH KEVIN J
• Format: Patent
• Language: English
• Published: 13.05.2015
• Subjects: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID 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 starting an internal combustion engine in a hybrid powertrain having an electric torque machine mechanically coupled to the internal combustion engine includes monitoring a temperature state of the hybrid powertrain, determining a maximum discharging power limit of the high-voltage battery corresponding to the temperature state of the hybrid powertrain, estimating an engine drag torque associated with the temperature state of the hybrid powertrain, selecting a preferred engine cranking speed associated with the estimated engine drag torque and achievable at less than the maximum discharging power limit of the high-voltage battery, and controlling the electric torque machine to generate a magnitude of motor torque output sufficient to crank the internal combustion engine at the preferred engine cranking speed.