Patent ID: 7571699

Claim:
A waste heat recovery system for a split-cycle engine, the split-cycle engine including an engine block having a compression cylinder for receiving air and a power cylinder for receiving air and fuel disposed therein, a gas passage interconnecting the compression cylinder and the power cylinder, and an engine coolant subsystem including a pump for pumping liquid engine coolant through the engine block to remove engine waste heat therefrom, the waste heat recovery system comprising: a heat exchange unit having a waste heat input for receiving the liquid engine coolant pumped from the engine, a waste heat outlet for returning the liquid engine coolant to the engine, a heat exchange medium inlet and a heat exchange medium outlet; a heat exchange medium circulation loop connected to the heat exchange medium inlet and heat exchange medium outlet of the heat exchange unit; a heat exchange medium circulating within the heat exchange medium circulation loop, wherein the heat exchange medium enters the heat exchange unit through the heat exchange medium inlet in a liquid phase, absorbs the engine waste heat from the engine coolant while passing through the heat exchange unit, and exits the heat exchange unit in a gas phase through the heat exchange medium outlet; an air compressor device having a heat exchange medium inlet connected to the heat exchange medium outlet of the heat exchange unit, a heat exchange medium outlet connected to the heat exchange medium circulation loop, an ambient air intake for drawing in ambient air and a compressed air outlet connected directly to the compression cylinder of the engine; wherein the gaseous heat exchange medium enters the heat exchange medium inlet of the air compressor device and exits the heat exchange medium outlet of the air compressor device to power the air compressor device with the engine waste heat from the engine coolant; wherein the air compressor device draws in ambient air through the ambient air intake, transfers engine waste heat energy from the gaseous heat exchange medium to the ambient air to produce waste-heat generated compressed air, and delivers the waste-heat generated compressed air directly to the compression cylinder of the engine through the compressed air outlet to recover the waste heat energy from the engine coolant.