What is the primary function of an electric vehicle's internal combustion generator in a PHEV?

The primary function of an electric vehicle's internal combustion generator in a Plug-in Hybrid Electric Vehicle (PHEV) is to serve as an auxiliary power source when needed. In a PHEV, the electric motor and battery typically handle most of the propulsion on electric power alone, especially in urban settings or short trips where the vehicle can operate in all-electric mode. However, when extra power is required—such as during heavy acceleration, extended distances, or when the battery's state of charge is low—the internal combustion engine (ICE) can kick in.

This generator provides additional power to support the electric motor without the need to stop and recharge the battery from an external source. It does not primarily charge the battery, but rather supplements the power system to ensure smooth operation and prevent range anxiety. By acting as an auxiliary power source, the ICE ensures that the vehicle can continue operating efficiently even when the electric range is depleted, thus enhancing the overall versatility and usability of the vehicle.