System and method for regulating EGR cooling using a rankine cycle

摘要

This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

主权项

1. A waste heat recovery system for an internal combustion engine, the waste heat recovery system comprising:
a fluid management circuit, including: a sub-cooler containing a liquid working fluid; a pump fluidly connected to the sub-cooler and operable to draw the liquid working fluid from the sub-cooler; a waste heat recovery circuit, including: a recuperator fluidly connected to the pump and configured to receive a first portion of the liquid working fluid from the pump and receive a vaporized working fluid, wherein heat is transferred from the vaporized working fluid to the first portion of the liquid working fluid, and wherein the first portion of the liquid working fluid flowing from a liquid working fluid recuperator outlet is at a first temperature; a first EGR boiler flow control valve fluidly connected to the pump in parallel with the recuperator so as to receive a second portion of the liquid working fluid from the pump at a second temperature lower than the first temperature; and a boiler including a first inlet fluidly connected to an exhaust circuit so as to receive EGR exhaust gas, a second inlet fluidly connected to the first EGR boiler flow control valve, and a third inlet fluidly connected to the liquid working fluid recuperator outlet via a second EGR boiler flow control valve, wherein the boiler receives the first portion of the liquid working fluid at the first temperature from the first EGR boiler flow control valve; and at least a portion of the second portion of the liquid working fluid flowing from the recuperator at the second temperature; wherein heat is transferred from the EGR exhaust gas to the liquid working fluid to cause the liquid working fluid to vaporize; and wherein the liquid working fluid at the second temperature is used to control the amount of cooling provided to the EGR exhaust gas.