WASTE HEAT UTILIZATION DEVICE FOR INTERNAL COMBUSTION

A waste heat utilization device (2) for an internal combustion engine (6) includes a heat medium circuit (8) through which a heat medium applied with waste heat from at least one of the engine and a heat source of the engine is circulated as the engine is operated, and a Rankine cycle circuit (4) through which a working fluid is circulated. The Rankine cycle circuit includes a heating unit (10, 12) for heating the working fluid by causing heat to transfer to the working fluid from at least one of the heat medium and the heat source, an expander (14) for expanding the working fluid introduced therein from the heating unit to produce driving force, and a condenser (16) for condensing the working fluid introduced therein from the expander. The working fluid is delivered from the condenser to the heating unit. The flow rate of at least one of the heat medium and the heat source that transfer heat to the working fluid in the heating unit is controlled in accordance with an operating condition of the engine.