1. The engine of a plug-in hybrid car is not directly used for charging.
2. The charging of plug-in hybrid vehicles mainly relies on external power sources, which are connected to charging stations or household power sources through charging interfaces to supplement the power battery with electrical energy.
3. The role of the engine in plug-in hybrid vehicles is mainly as one of the power sources. When the battery is low or requires higher power output, the engine starts and drives the generator to generate electricity, or works in conjunction with the electric motor to jointly drive the vehicle. However, this process does not directly charge the battery, but achieves effective utilization of power through energy conversion and distribution systems.