Dodge Nitro. Manual — part 612

Fig. 11: Muffler/Resonator Assembly
Courtesy of CHRYSLER LLC

1. Install muffler and tailpipe assembly in vehicle and attach to exhaust hangers.

2. Install muffler and tailpipe assembly to exhaust pipe.

3. Install clamp. Tighten nut to 32 N.m. (24 ft. lbs.).

4. Lower vehicle from hoist.

SHIELDS-HEAT

DESCRIPTION

DESCRIPTION

1 - CATALYTIC CONVERTER PIPE
2 - CLAMP
3 - MUFFLER/RESONATOR/TAILPIPE ASSEMBLY
4 - HANGER ROD

2007 Dodge Nitro R/T

2007 ENGINE Exhaust System And Turbocharger - Nitro

Fig. 12: Front & Rear Floor Pan Heat Shields Typical
Courtesy of CHRYSLER LLC

Heat shields (1) (3) are needed to protect both the vehicle and the environment from the high temperatures
developed by the catalytic converter. The catalytic converter releases additional heat into the exhaust system.
Under severe operating conditions, the temperature increases in the area of the converter. Such conditions can
exist when the engine misfires or otherwise does not operate at peak efficiency. See Fig. 12.

FILTER-DIESEL PARTICULATE

DESCRIPTION

DESCRIPTION

A diesel particulate filter DPF is installed for exhaust gas after-treatment. The DPF is located downstream of the
main oxidation catalyst. The DPF filters, stores and burns particulate matter (soot) that is generated during the
combustion process. The soot is oxidized to carbon dioxide CO2 at exhaust temperatures over 600°C (1,112°F).

1 - REAR FLOOR PAN HEAT SHIELD
2 - HEAT SHIELD RETAINING NUTS
3 - FRONT FLOOR PAN HEAT SHIELD

2007 Dodge Nitro R/T

2007 ENGINE Exhaust System And Turbocharger - Nitro

OPERATION

OPERATION

The oxidation catalysts raise the exhaust gas temperatures to regenerate the DPF , which is passive regeneration.
If the passive regeneration cannot keep up with the build up of soot in the DPF, the ECM will actively
regenerate the DPF to burn off the soot. Residue remains inside the DPF in the form of non burnable ash. Ash
comes from the oils and other materials that are trapped in the oils and are present in the soot. Ash is not
eliminated by the regeneration cycle. Excessive ash accumulation requires the replacement of the DPF. The
DPF uses a silicon carbide wall-flow monolith with a platinum coating to trap particulates. The monolith
contains a large number of square parallel channels, which run in the axial direction and are separated by thin
porous walls. The channels are alternatively open at one end, but plugged at the other. The exhaust gases flow
through the walls and escape through the pores in the wall material. Particulates, however, are too large to
escape and are trapped in the monolith walls. The ECM starts the regeneration of the DPF if the soot load
exceeds a performance map value. The ECM determines the load condition of the DPF based upon the exhaust
gas pressure upstream and downstream of the DPF. A pressure differential sensor provides the pressure input to
the ECM. During the regeneration process, the ECM raises the temperature in the DPF to burn off the soot
accumulated. Under normal operation, the engine does not produce enough heat to oxidize the soot inside the
DPF. This process requires temperatures above 550°C (1,022°F). After regeneration, the ECM reads the actual
pressure difference at the DPF and compares it with a reference value. From this comparison, the ECM
determines the ash quantity inside the DPF.

REMOVAL

REMOVAL

Fig. 13: Exhaust System - 2.8L Diesel - W/DPF
Courtesy of CHRYSLER LLC

1 - MANIVERTER
2 - MANIVERTER TO DFP FLANGE

2007 Dodge Nitro R/T

2007 ENGINE Exhaust System And Turbocharger - Nitro

1. Disconnect negative battery cable.

2. Raise and support vehicle.

3. Disconnect differential pressure hoses from pressure sensor tubing (3).

4. Disconnect oxygen sensor electrical connector.

5. Remove muffler and tail pipe to DFP flange nuts.

6. Remove the DFP to exhaust manifold nuts.

7. Remove steady rest mounting bolts (4).

8. Remove the diesel particulate filter assembly.

INSTALLATION

INSTALLATION

Fig. 14: Exhaust System - 2.8L Diesel - W/DPF
Courtesy of CHRYSLER LLC

3 - PRESSURE SENSOR TUBING
4 - STEADY MOUNT
5 - FLEXIBLE BELLOWS
6 - ISOLATOR
7 - MUFFLER/TAIL PIPE ASSEMBLY
8 - DPF TO MUFFLER FLANGE

1 - MANIVERTER
2 - MANIVERTER TO DFP FLANGE
3 - PRESSURE SENSOR TUBING
4 - STEADY MOUNT
5 - FLEXIBLE BELLOWS

2007 Dodge Nitro R/T

2007 ENGINE Exhaust System And Turbocharger - Nitro