Hybrid Electric Vehicles (HEVs) typically have power supplied by a battery powered electric motor, an engine, or a combination thereof. Some HEVs have a plug-in feature which allows the battery to be connected to an external power source for recharging, and are called Plug-in HEVs (PHEVs). Electric-only mode (EV mode) in HEVs and PHEVs allows the vehicle to operate using the electric motor alone, while not using the engine. Operation in EV mode may enhance the ride comfort by providing lower noise and better driveability of the vehicle, e.g., smoother electric operation, lower noise, vibration, and harshness (NVH), and faster vehicle response. Operation in EV mode also benefits the environment with zero emissions from the vehicle during this period of operation.