B3000 2WD V6-3.0L OHV (1994)
Catalytic Converter: Description and Operation
PURPOSE
The Three-Way Catalytic Converter (TWC) is mounted under the vehicles body within the exhaust system, and is designed to convert harmful
exhaust gas pollutants, Carbon Monoxide (CO), Hydrocarbons (HC), and Oxides of Nitrogen (NOx) to harmless by-products of Nitrogen (N),
Carbon Dioxide (CO2) and water vapor (H2O) through a catalytic chemical reaction.
Single Brick Catalytic Converter
CONSTRUCTION
The TWC contains one or two ceramic monolithic honeycomb substrates. The substrate bricks or beds are impregnated with the catalyzing
element(s), then covered by a wire mesh sleeve for insulation and protection from shock and severe jolts. A diffuser inside the shell allows the
exhaust gases to flow uniformly over the entire area of the substrate.
Dual Brick Catalytic Converter
THE OXIDATION REACTION
In order to change (HC) and (CO) into harmless materials, the catalytic elements (platinum and palladium) start an oxidation, or burning, reaction
in the catalytic converter. Oxidation is the addition of oxygen to an element or compound. During the oxidation process, Oxygen (O2) mixes with
the excess (HC) and (CO) to form (H2O) and (CO2).
Caution should be taken while working on or around catalytic converters and other exhaust system components, due to the considerable heat (900°
F to 1,600°F) that is generated during the oxidation process.
