Patent ID: 7454912

Claim:
A waste heat utilization device for utilizing waste heat from a heat engine mounted on a vehicle, comprising: a refrigerating cycle for an automotive air conditioning system, having an expansion-compressor device for compressing refrigerant, a condenser device, and an evaporator; a Rankine cycle including: a heating device for heating, by means of the waste heat from the heat engine, working fluid circulated by a pump to transform the working fluid to heated vapor; the expansion-compressor device for generating a driving power by means of expansion of the heated vapor from the heating device; and the condenser device, commonly used for the refrigerating cycle, for condensing the heated vapor from the expansion-compressor device to transform the heated vapor to condensed fluid and sending the condensed fluid to the pump; and a controller for controlling an operation of the refrigerating cycle and the Rankine cycle, wherein in a case that a temperature of the waste heat from the heat engine is higher than a predetermined temperature, and the controller determines that a demand for operating the refrigerating cycle is not existing, the controller calculates an optimum heat collection amount (Qho) which is to be collected from the heat engine, and which is correlated with a heat radiation amount (Qc) to be radiated at the condenser device in an operating condition of the waste heat utilization device at a time that such a calculation is made; and the controller controls a flow amount (G) of the working fluid to collect the heat collection amount (Oho), so that the driving power (L), which is defined by an actual heat collection amount and an actual heat radiation amount, is efficiently generated at the expansion device-compressor.