Rankine cycle waste heat recovery system and method with improved EGR temperature control

摘要

A waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling is described. More particularly, a Rankine cycle WHR system and method is described, including an arrangement to improve the precision of EGR cooling for engine efficiency improvement and thermal management.

主权项

1. An internal combustion engine, comprising:
an exhaust gas recirculation (EGR) system containing an EGR gas; and a waste heat recovery (WHR) system adapted to provide cooling to the EGR gas, the WHR system including a WHR circuit, a fluid containment portion, a feed pump operable to pump a working fluid from the fluid containment portion through the WHR circuit, at least one heat exchanger positioned downstream from the feed pump and operable to convert the working fluid from a liquid to a high-pressure vapor by transferring heat from the EGR gas to the working fluid, an energy conversion portion positioned between the heat exchanger and the fluid containment portion, an EGR temperature control circuit connected to the WHR circuit and positioned to receive the working fluid from the WHR circuit downstream of the fluid containment portion and to return the working fluid to the WHR circuit upstream of the fluid containment portion, a thermal control unit positioned along the EGR temperature control circuit to cool the EGR gas, and a pressure reduction device positioned along the EGR temperature control circuit upstream of the thermal control unit to reduce the pressure of the working fluid sufficient to create a phase change of the working fluid.