49–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the en-
gine or motor, set the parking brake, and chock
the tires. Before working under the vehicle, always
place jack stands under the frame rails to ensure
the vehicle cannot drop. Failure to follow these
steps could result in serious personal injury or
death.
49–01 Exhaust System
Inspection (Noise
Emission Control)
In addition to inspecting the exhaust system at the
scheduled maintenance interval, inspect the exhaust
system if the noise level of the vehicle has in-
creased. Freightliner Trucks recommends replacing
parts that show leakage, wear, or damage, with
genuine Freightliner parts.
The exhaust system must be free of leaks, binding,
grounding, and excessive vibrations. These condi-
tions are usually caused by loose, broken, or mis-
aligned clamps, brackets, or pipes. If any of these
conditions exist, check the exhaust system compo-
nents and alignment. Align or replace as necessary;
see Group 49 of the 108SD and 114SD Workshop
Manual, or take the vehicle to an authorized Freight-
liner dealer.
It is a violation of US federal law to alter exhaust
plumbing or aftertreatment in any way that would
bring the engine out of compliance with certification
requirements. (Ref: 42 U.S.C. S7522(a) (3).) It is the
owner’s responsibility to maintain the vehicle so that
it conforms to EPA regulations.
EPA10 and Newer Exhaust
System
Definitions of Aftertreatment (ATS)
Terms
NOTE: Diagrams of ATS configurations are pro-
vided later in this chapter. For Detroit Diesel,
see
Fig. 1, Fig. 2, and Fig. 3. For Cummins,
see
Fig. 4, Fig. 5, and Fig. 6.
Refer to the following list of definitions of ATS terms
and components.
• Aftertreatment System (ATS)—the entire ex-
haust system from the turbocharger to the ex-
haust stack or tail pipe.
• Aftertreatment Device (ATD)—a housing that
contains the DOC and DPF.
• BlueTec®—Daimler’s proprietary SCR technol-
ogy.
• Diesel Oxidation Catalyst (DOC)—a flow
through device located at the ATD inlet that en-
hances the oxidation of hydrocarbons in order
to reduce particulate emissions.
• Diesel Particulate Filter (DPF)—a device in-
stalled on a diesel engine system that captures
and reduces particulate matter (PM) from the
exhaust gas.
• Diesel Exhaust Fluid (DEF)—the chemical agent
that reacts with the exhaust gases in the SCR
to reduce NOx.
• DEF Pump—filters and supplies DEF to the
DEF metering unit.
• DEF Tank—holds DEF and regulates its tem-
perature.
• DEF Metering Unit—mixes DEF with com-
pressed air, and meters this mixture into the
exhaust flow via an injection nozzle.
• SCR Catalyst—the housing containing a treated
ceramic flow-through block where the DEF and
exhaust gases undergo selective catalytic re-
duction (SCR).
• Selective Catalytic Reduction (SCR)—a process
used to reduce NOx emissions.
Exhaust 49
108SD and 114SD Maintenance Manual, December 2015 49/1
To Next Page
Loading...
