ENGINE STOP DETERMINATION DEVICE AND ENGINE STOP DETERMINATION METHOD

A cooling system for an engine in the present invention includes a first coolant route for circulating coolant between a water jacket of an engine main body and a heater core, a second coolant route for circulating the coolant between a waste heat recovery unit and the heater core, a first water-temperature sensor provided on the first coolant route, and a second water-temperature sensor provided on the second coolant route. An engine control unit makes an engine stop determination based on the coolant temperatures detected by the first water-temperature sensor and the second water-temperature sensor and, in making the engine stop determination, selectively uses the coolant temperatures detected by the first water-temperature sensor and the second water-temperature sensor in dependence on whether a heater unit including the heater core is in an operation state or in an out-of-operation state.