US Patent 7454912 Device for utilizing waste heat from heat engine

A device for utilizing waste heat from a heat engine comprises a Rankine cycle including a pump, a heating device, an expansion device, and a condenser device, and a controller for controlling an operation of the Rankine cycle. The controller calculates an optimum heat collection amount (Qho) as a heat value to be collected from waste heat of the engine, wherein the heat collection amount (Qho) is calculated as an optimum amount in relation to a potential maximum heat radiation amount (Qco) to be radiated at the condenser device. The controller calculates an optimum flow amount (G) of refrigerant corresponding to the optimum heat collection amount (Qho), so that a maximum driving power (L) is generated at the expansion device.