working fluid entering lower temperature portion 153 measured by temperature sensor 141 provides additional cooling of egr exhaust gas prior to the egr exhaust gas returning to the egr system liquid working fluid flows through boiler portion 153 into moderate temperature portion 154 exiting egr boiler 374 at outlet 374 e the temperature of the liquid working fluid flowing through low temperature portion 153 and moderate temperature portion 154 may be monitored with temperature sensor 143 and temperature sensor 145 which assists control module 450 in determining the additional cooling capability of the liquid working fluid as well as the additional heat that needs transferred to the liquid working fluid to boil after passing through pre cac 52 and exhaust heat exchanger 56 the liquid working fluid enters egr boiler 374 at inlet 374 d the higher temperature of the liquid working fluid entering inlet 374 d measured by temperature sensor 147 in combination with the temperature of the egr exhaust gas acts to quickly convert the liquid working fluid into a vapor which proceeds through outlet 374 f to conduit 80 and then downstream to energy conversion device 78 the various temperature sensors in combination with the various valves of the system regulate the amount of cooling provided to egr exhaust gas as it travels through the various portions of boiler 374 while regulating the amount of heating provided to the liquid working fluid thus improving the amount of cooling provided to the egr exhaust gas while assuring the.