Patent ID: 8655526
Filing Date: 2014-02-18
Classification: B60W,F02D,F02N,G06F,Y02T

Abstract:
1. Method for starting an internal combustion engine in a hybrid powertrain including an electric torque machine mechanically coupled to the internal combustion engine and electrically coupled to a high-voltage battery via an inverter, the method comprising: 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, the preferred engine cranking speed comprising a maximum engine cranking speed that is associated with the estimated engine drag torque and a discharge power that is less than the maximum discharging power limit of the high-voltage battery and greater than an engine speed range associated with a system resonant frequency; and controlling the electric torque machine to generate a magnitude of motor torque output to crank the internal combustion engine at the preferred engine cranking speed.