Patent ID: 8170737

Claim:
A method of controlling a powertrain of a vehicle having an engine, a motor, and a battery; wherein the battery is operatively connected with the motor to power the motor for propelling the vehicle using energy stored in the battery; the method comprising: monitoring a state of charge of the battery; determining whether to turn the engine on during operation in an electric-only operating mode based at least in part on the state of charge of the battery and whether the vehicle is within different predetermined distances of different locations, each of said different locations being one of different categories of locations; wherein one of said categories of locations is charging locations and another of said categories of locations is parking locations associated with parking for greater than a predetermined period of time without charging; starting the engine if the state of charge of the battery is less than a first predetermined state of charge and the vehicle is not within a first predetermined distance of one of the charging locations; starting the engine if the state of charge of the battery is less than a second predetermined state of charge that is less than the first predetermined state of charge; and starting the engine if the state of charge of the battery is less than a third predetermined state of charge that is greater than the first predetermined state of charge and the vehicle is within a second predetermined distance of one of the parking locations.