GHG17 DD Medium Duty Operators Manual Exhaust Gas Recirculation System The Exhaust Gas Recirculation (EGR) system consists of an EGR cooler and EGR valve. The EGR valve allows hot exhaust gas to enter the EGR cooler. Heat is extracted from the exhaust gas, resulting in cooler exhaust gas to the cylinders. EGR lowers the temperature of the exhaust from the engine, therefore, reducing exhaust gas emissions to acceptable levels. The purpose of the Exhaust Gas Recirculation System (EGR) is to reduce engine exhaust gas emissions in accordance with EPA regulations.
The EGR system has been optimized to dramatically cut NOx formation by routing a measured amount of exhaust flow to the cylinders to lower combustion temperatures. Lower temperatures result in lower NOx levels without the negative effects of retarding engine timing. The EGR valve has been moved to the top of the engine for improved serviceability. Engines for on-highway EPA 2007 regulation applications use a cooled EGR system along with an Aftertreatment System to meet the emission standards. All information subject to change without notice. 39 DDC-SVC-MAN-0192 Copyright © 2017 DETROIT DIESEL CORPORATION