Patent ID: 8219273

Claim:
A method of starting an internal combustion engine of a vehicle with a hybrid-electric powertrain having an internal combustion engine, a generator, and a high-voltage battery pack, the method comprising: receiving an internal combustion engine start input signal; determining a load on a electric motor and generator; transmitting torque to the internal combustion engine with torque from the electric motor and generator when the load on the electric motor and generator is below a predetermined load threshold; transmitting torque to the internal combustion engine with torque from an exogenous starting device when the load on the electric motor and generator is above the predetermined load threshold; determining a state of charge of a high-voltage battery pack; transmitting torque to the internal combustion engine with torque from the electric motor and generator when the state of charge of the high-voltage battery pack is above a predetermined charge level threshold; and transmitting torque to the internal combustion engine with torque from the exogenous starting device when the state of charge of the high-voltage battery pack is below the predetermined charge level threshold.