Special Tools; Exhaust System; Catalytic Converter(S) Description; Operation - Dodge Intrepid Service Manual

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EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

SPECIAL TOOLS

EXHAUST SYSTEM
DRB III & PEP Module - OT-CH6010A
Back Pressure Test Adapter - CH8519
Pressure Transducer CH7063
CATALYTIC CONVERTER(S)
DESCRIPTION
The close coupled, three-way catalytic converter
inlets are connected to the exhaust manifolds by the
use of V-Band clamps (Fig. 5). The left side converter
outlet pipe connects to the exhaust system. The right
side converter connects to an extension pipe (Fig. 5).

OPERATION

The three-way catalytic converter simultaneously
converts three exhaust emissions into harmless
gases. Specifically, HC and CO emissions are con-
Fig. 5 Catalytic Converters
1 - V-BAND CLAMPS
2 - BAND CLAMP
3 - EXTENSION PIPE
4 - CATALYTIC CONVERTERS
verted into water (H2O) and carbon dioxide (CO2).
Oxides of Nitrogen (NOx) are converted into elemen-
tal Nitrogen (N) and water. The three-way catalyst is
most efficient in converting HC, CO and NOx at the
stoichiometric air fuel ratio of 14.7:1.
The oxygen content in a catalyst is important for
efficient conversion of exhaust gases. When a high
oxygen content (lean) air/fuel ratio is present for an
extended period, oxygen content in a catalyst can
reach a maximum. When a rich air/fuel ratio is
present for an extended period, the oxygen content in
the catalyst can become totally depleted. When this
occurs, the catalyst fails to convert the gases. This is
known as catalyst punch through.
Catalyst operation is dependent on its ability to
store and release the oxygen needed to complete the
emissions-reducing chemical reactions. As a catalyst
deteriorates, its ability to store oxygen is reduced.
Since the catalyst's ability to store oxygen is some-
what related to proper operation, oxygen storage can
be used as an indicator of catalyst performance.
Refer to the appropriate Powertrain Diagnostic Pro-
cedure for diagnosis of a catalyst related Diagnostic
Trouble Code (DTC).
The combustion reaction caused by the catalyst
releases additional heat in the exhaust system, caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency. Do not remove spark
plug wires from plugs or by any other means short
out cylinders, if exhaust system is equipped with a
catalytic converter. Failure of the catalytic converter
can occur due to temperature increases caused by
unburned fuel passing through the converter. This
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