Rankine cycle mid-temperature recuperation

Abstract

A system and method for recuperation is provided including a boiler wherein air and exhaust gas recirculation pass through the boiler and are cooled by thermal transfer with a coolant. The system includes an expander receiving coolant from the boiler, a recuperator receiving coolant from the expander, a condenser receiving coolant from the recuperator; a pump pumping coolant from the condenser to a low temperature portion of the boiler, and a valve, which allows coolant to pass directly from the boiler to the recuperator.

1 . A recuperation system including:
 a boiler, wherein air and exhaust gas recirculation pass through the boiler and are cooled by thermal transfer with a coolant;   an expander receiving coolant from the boiler;   a recuperator receiving coolant from the expander;   a condenser receiving coolant from the recuperator;   a pump pumping coolant from the condenser to a low temperature portion of the boiler; and   a valve, wherein the valve allows coolant to pass directly from the boiler to the recuperator.   
     
     
         2 . The system of  claim 1  wherein the valve is a three-way valve. 
     
     
         3 . The system of  claim 1  further including a temperature sensor detecting the temperature at the intake manifold. 
     
     
         4 . The system of  claim 3  further including a valve control controlling the valve. 
     
     
         5 . The system of  claim 4  wherein the valve control receives an indication of the temperature at the intake manifold from the temperature sensor. 
     
     
         6 . The system of  claim 5  wherein the valve control adjusts the position of the valve in response to the temperature at the intake manifold. 
     
     
         7 . A recuperation method including:
 cooling air and exhaust gas recirculation passing through a boiler by thermal transfer with a coolant;   receiving the coolant from the boiler at an expander;   receiving the coolant from the expander at a recuperator;   receiving the coolant from the recuperator at a condenser;   pumping coolant from the condenser to a low temperature portion of the boiler; and   actuating a valve to allow coolant to pass directly from the boiler to the recuperator.   
     
     
         8 . The method of  claim 7  wherein the valve is a three-way valve. 
     
     
         9 . The method of  claim 7  further including detecting the temperature at the intake manifold using a temperature sensor. 
     
     
         10 . The method of  claim 9  further including controlling the valve using a valve control. 
     
     
         11 . The method of  claim 10  wherein the valve control receives an indication of the temperature at the intake manifold from the temperature sensor. 
     
     
         12 . The method of  claim 11  wherein the valve control adjusts the position of the valve in response to the temperature at the intake manifold.