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DESCRIPTION AND OPERATION
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.
1. Exhaust Valve Seat (with 30-Degree Contact Face) 2. Inlet Valve Seat (with 20-Degree Contact Face)
5-111.bk Page 18 Monday, July 10, 2006 2:26 PM
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