Exhaust gas recirculation system with control of EGR gas temperature

摘要

A method and system for controlling the temperature of recirculated exhaust gas in an exhaust gas recirculation (EGR) system, such as those used in connection with diesel engines. An EGR loop (which may be either a high pressure loop or a low pressure loop) has a dual-leg segment with an EGR cooler on one leg and an EGR heater on the other leg. By means of a valve, the EGR gas may be diverted to either one leg or the other, thereby providing either cooled or heated EGR gas to the engine.