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DESCRIPTION AND OPERATION
ENGINE DESIGN FEATURES
(ASET™ AC ENGINES)
In the fall of 2002, Mack Trucks introduced two
new engines that comply with changes in
governmental laws regulating engine emissions.
Both engines evolved from the E7 E-Tech™ and
continue with the electronic unit pump (EUP) fuel
injection system and the V-MAC
®
III electronic
control system. The core change in the design of
the two new engines, however, is the use of
exhaust gas recirculation to lower combustion
temperatures for control of nitrogen oxides (NOx).
Two different methods are used to accomplish
this control. The methods are:
앫 Internal Exhaust Gas Recirculation
(IEGR) — AI/AMI engine
앫 Cooled Exhaust Gas Recirculation
(CEGR) — AC engine
This manual covers only the ASET™ AC engine’s
CEGR design, in which a portion of the exhaust
gas is “cooled” externally before it is recirculated
through the combustion chambers. The ASET™
AI engine’s IEGR design receives complete
service coverage in ASET™ AI/AMI Engines
Service Manual 5-110. Regardless of the method
used, CEGR or IEGR, both designs are
improvements based on changes in several
design features of the E7 E-Tech™ current
controlled rate shaping (CCRS) engine. The
changes are more extensive and visible for the
AC engine which is used in linehaul applications
at lower governed speeds, than the AI engine
which is used in vocational applications at higher
governed speeds.
For linehaul operations covered by the CH and
CX models, the AC engine lineup provides the
optimum in economy and performance with
reduced NOx emissions. Included are both
Econodyne
®
and Maxicruise
®
.
ASET™ AC ENGINE APPLICATIONS
The MACK PowerLeash™ engine brake was
introduced on ASET™ engines during mid-2003.
The PowerLeash™ brake is integrated into the
rocker shaft assemblies and uses the standard
height cylinder head cover. Compared to add-on
engine brakes, the PowerLeash™ brake has
lighter weight, increased braking output,
improved response and more consistent
operation.
Engine Chassis
ASET™ AC MAXICRUISE
®
AC-310/330 CH, CX
AC-330/350 CH, CX
AC-355/380 CH, CX
AC-380/410 CH, CX
ASET™ AC ECONODYNE
®
AC-350 CH, CX
AC-400 CH, CX
AC-427 CH, CX
AC-460 (E) CH, CX
AC-460 (P) CH, CX
5-111.bk Page 16 Monday, July 10, 2006 2:26 PM
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