US Patent 7752840 Engine exhaust heat exchanger

A heat transfer system in an engine for transferring heat from the recirculated exhaust gas to an output of an engine exhaust system. The heat transfer may cool the recirculated exhaust for reduced emissions from engine combustion and, at the same time, increase the output exhaust temperature to facilitate regeneration of an exhaust aftertreatment system. There may a heat transfer unit at the output of an exhaust gas recirculating valve connected to a heat transfer unit at the output of the exhaust system.