A vehicle includes: an engine including cylinder, a piston, a crankshaft unit, a balancing shaft unit, and an engine cooling passage; a power generating system including a generator and a generator cooling passage; and a cooling system that includes a mechanical water pump driven by the crankshaft unit, a first heat exchanger in fluid communication with the mechanical water pump and the engine cooling passage to constitute a first cooling circuit, an electrically controlled water pump, a second heat exchanger in fluid communication with the electrically controlled water pump and the generator cooling passage to constitute a second cooling circuit, and a controlling unit for controlling operation of the electrically controlled water pump.