Freightliner Business Class M2. Instruction - page 32

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, 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 can not drop. Failure to follow these steps
could result in serious personal injury or death.

49–01 Exhaust System

Inspecting (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 Business Class® M2 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

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 (also the SCR and
the mixing tube in one-box systems).

• BlueTec®—Daimler’s proprietary SCR technol-

ogy.

• Diesel Oxidation Catalyst (DOC)—a flow-

through device that oxidizes soot in the ATD.

• Diesel Particulate Filter (DPF)—a component in

the ATD that traps soot 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.

Inspection

To meet EPA10 emissions regulations for vehicles
domiciled in the USA or Canada, engines manufac-
tured after December 31, 2009 are equipped with an
emission aftertreatment system. Vehicles domiciled
outside of the USA and Canada may not have after-
treatment equipment, depending upon local statutory
emissions guidelines.

IMPORTANT: The aftertreatment device (ATD),
which is part of the aftertreatment system (ATS),
requires special attention during regularly
scheduled maintenance inspections. No leaks
are allowed anywhere in the system. If any dis-
crepancies are discovered, refer to the engine
manufacturer’s service literature for repair in-
structions.

Exhaust

49

Business Class M2 Maintenance Manual, November 2015

49/1

1.

Check for leakage at the clamp that attaches the
exhaust pipe to the turbocharger exhaust outlet.
If leakage exists, tighten the nut on the clamp to
the required torque. If leakage persists, install a
new clamp.

2.

Check the exhaust pipe, bellows, and each ex-
haust seal clamp for leakage, wear, cracks, or
damage. Replace damaged components as
needed. If leakage exists at a clamp, tighten the
nuts to the required torque. If leakage persists,
install a new exhaust seal clamp. Do not reuse
seal clamps. Once a seal clamp is loosened or
removed, it must be replaced.

3.

If present, check the condition of the insulation
material around the exhaust pipe between the
turbocharger and the ATD.

4.

Check the ATD mounting bands for tightness.
Tighten to 30 lbf·ft (41 N·m) if needed. Do not
overtighten.

5.

Check for leaks around the clamps that attach
the ATD in the ATS, and around the clamps that
retain the DPF in the ATD.

6.

Check all sensors attached to the ATS for leaks
or damaged wires. No leaks are allowed. See

Fig. 1

,

Fig. 2

, or

Fig. 3

for Detroit Diesel ATS

sensor locations.

7.

Check the DPF exterior surface for dents or
other damage. A dent over 3 inches (76 mm) in
diameter and 1/4-inch (6-mm) deep could cause
internal damage to the DPF, causing it to
malfunction.

8.

Check the SCR catalyst for dents and other
damage.

9.

Check for heat discoloration on the surface of
the ATD. Heat discoloration may indicate internal
damage; especially around the DPF.

NOTE: Diesel exhaust fluid creeps, causing
white crystals to form around the line fittings.
The presence of crystals does not mean the
system has a leak. Replacing fittings or trouble-
shooting components is not necessary unless
there is a system failure or a fault code.

10. Check the DEF tank, pump, metering unit, and

lines for leaks. See Section 49.03 of the
Business Class® M2 Workshop Manual for repair
procedures.

11. Check any wires, lines, or hoses within 4 inches

(10 cm) of the exhaust system for heat damage.
Repair or reroute as needed.

Diesel Exhaust Fluid (DEF) Filter
Replacement

The Environmental Protection Agency’s 2010 regula-
tions require lower nitrogen oxide (NOx) exhaust
emissions. Selective catalytic reduction (SCR) uses
diesel exhaust fluid (DEF) to lower NOx emissions in
the vehicle exhaust. A filter in the DEF pump pre-
vents clogging of the DEF metering unit injection
nozzle.

See the engine manufacturer’s maintenance manual
for filter replacement instructions and maintenance
intervals.

EPA07 Exhaust System

Definitions of ATS Terms

Refer to the following list of definitions of ATS com-
ponents.

• Aftertreatment System (ATS)—the entire ex-

haust system from the turbocharger to the ex-
haust stack or tail pipe.

• Aftertreatment Device (ATD)—a muffler-like can-

ister that houses a DPF, DOC, and sensors.

• Diesel Particulate Filter (DPF)—a filter that col-

lects and holds particulate matter (soot and
ash).

• Diesel Oxidation Catalyst (DOC)—oxidizes hy-

drocarbons and reduces NOx.

• Sensors—detect temperatures and pressures in

the ATS.

Inspection

To meet EPA07 emissions regulations for vehicles
domiciled in the USA or Canada, engines manufac-
tured after December 31, 2006 are equipped with an
emission aftertreatment system. Vehicles domiciled
outside of the USA and Canada may not have after-
treatment equipment, depending upon local statutory
emissions guidelines.

IMPORTANT: The aftertreatment device (ATD),
which is part of the aftertreatment system (ATS),
requires special attention during regularly
scheduled maintenance inspections; see

Fig. 4

.

Exhaust

49

Business Class M2 Maintenance Manual, November 2015

49/2

No leaks are allowed anywhere in the system. If
any discrepancies are discovered, refer to the
engine manufacturer’s service literature for re-
pair instructions.

1.

Check for leakage at the clamp that attaches the
exhaust pipe to the turbocharger exhaust outlet.
If leakage exists, tighten the nut on the clamp to
the required torque. If leakage persists, install a
new clamp.

2.

Check the exhaust pipe, bellows, and each ex-
haust seal clamp for leakage, wear, cracks, or
damage. Replace damaged components as
needed. If leakage exists at a clamp, tighten the
nuts to the required torque. If leakage persists,
install a new exhaust seal clamp. Do not reuse
seal clamps. Once a seal clamp is loosened or
removed, it must be replaced.

3.

If present, check the condition of the insulation
material around the exhaust pipe between the
turbocharger and the ATD.

4.

Check the ATD mounting bands for tightness.
Tighten to 30 lbf·ft (41 N·m) if needed. Do not
overtighten.

5.

Check for leaks around the clamps that attach
the ATD in the ATS, and around the clamps that
retain the DPF in the ATD.

6.

Check all sensors attached to the ATD for leaks
or damaged wires. No leaks are allowed.

7.

Check the DPF exterior surface for dents or
other damage. See Item A of

Fig. 4

. A dent over

3 inches (76 mm) in diameter and 1/4-inch (6-
mm) deep could cause internal damage to the
DPF, causing it to malfunction.

08/20/2009

f490355

1

2

3

4

5

6

7

8

9

10

11

12

13

14

9

15

NOTE: The sensor box (item 8) contains the SCR inlet and outlet NOx sensors, DPF outlet pressure sensor, and the
DOC inlet pressure sensor.

1.

DOC Outlet Temperature
Sensor

2.

DOC Inlet Pressure Sensor
Port

3.

DOC Inlet Temperature Sensor

4.

Front Heat Shield

5.

DEF Nozzle

6.

Exhaust Outlet

7.

DEF Metering Unit

8.

Sensor Box (see note above)

9.

Exhaust Inlet

10. SCR Outlet Temperature

Sensor

11. SCR Outlet NOx Sensor Port
12. SCR Inlet NOx Sensor Port
13. 14-Pin Connectors
14. DPF Outlet Pressure Sensor

Port

15. SCR Inlet Temperature Sensor

Fig. 1, One-Box ATS Sensor Locations

Exhaust

49

Business Class M2 Maintenance Manual, November 2015

49/3

8.

Check for heat discoloration on the surface of
the ATD. Heat discoloration may indicate internal
damage; especially around the DPF.

9.

Check any wires, lines, or hoses within 4 inches
(10 cm) of the exhaust system for heat damage.
Repair or reroute as needed.

Pre-EPA07 Exhaust System
Inspection

1.

Inspect the exhaust manifold at the cylinder head
and at the turbocharger for leaks. See the engine
manufacturer’s service literature for repair proce-
dures.

2.

Inspect the muffler body, muffler outlet stack,
muffler shield, and inlet tubes for leakage, dents,
corrosion, or holes in the muffler.

3.

Inspect the exhaust pipe and each exhaust seal
clamp for leakage, wear, or damage. Replace the
exhaust pipe if needed. If leakage exists at a
clamp, tighten the nuts to the required torque. If
leakage persists, install a new exhaust seal
clamp. Do not reuse seal clamps. Once a seal
clamp is loosened or removed, it must be re-
placed.

4.

Check for leakage at the clamp that attaches the
exhaust pipe to the turbocharger exhaust outlet.
If leakage exists, tighten the nut on the clamp to

09/16/2009

1

2

3

4

5

6

7

8

9

10

11

f490353

10

9

8

1.

DEF Metering Unit

2.

DEF Nozzle

3.

SCR Outlet Temperature
Sensor

4.

SCR Inlet Temperature Sensor

5.

DOC Inlet Temperature Sensor

6.

DOC Inlet Pressure Sensor

7.

DPF Inlet Temperature Sensor

8.

DPF Outlet Pressure Sensor

9.

DPF Outlet Temperature
Sensor

10. DPF Outlet NOx Sensor
11. SCR Outlet NOx Sensor

Fig. 2, 2V2 Two-Box ATS Sensor Locations

Exhaust

49

Business Class M2 Maintenance Manual, November 2015

49/4

Рассказать друзьям

Страницы