Patent attributes
An engine cooling system (22) includes an engine (11), an engine cooling pipe line (23), an engine water pump (24) and an engine radiator (25). An electricity storage device cooling system (27) includes an electricity storage device (19), an electricity storage device cooling pipe line (28), an electricity storage device water pump (29) and an electricity storage device radiator (31). Different heat-transfer media (engine cooling water and electricity storage device cooling water) flow respectively in the engine cooling system (22) and the electricity storage device cooling system (27). Further, a heating heat exchanger (32) is provided in the halfway of the engine cooling pipe line (23) and in the halfway of the electricity storage device cooling pipe line (28) for performing heat exchange between the engine cooling water and the electricity storage device cooling water.