5-111.bk Page 18 Monday, July 10, 2006 2:26 PM 7 Figure 7 — Redesigned Valve Seat Inserts With the ASET™ AC (CEGR) engine technology, exhaust gas is recirculated by first being cooled and then mixed with the charged inlet air prior to entering the cylinder. While this leads to a more complex system with additional hardware, it works effectively to reduce NOx emissions and maintain fuel economy in linehaul applications with lower engine operating speed ranges. The additional hardware required for the CEGR engine exhaust gas recirculation includes components to meter exhaust gases from the exhaust manifold for mixing with the charge air prior to entering the inlet manifold.
An engine coolant cooled EGR cooler is used to reduce the exhaust gas temperature before it is released into the EGR mixing tube. The system also makes use of a variable geometry turbocharger and a more powerful engine electronic control unit (with additional sensor inputs) to provide the precision control required for the CEGR technology. Page 18 DESCRIPTION AND OPERATION 1. Exhaust Valve Seat (with 30-Degree Contact Face) 2. Inlet Valve Seat (with 20-Degree Contact Face)