Catalytic Converter: Description and Operation

Catalytic Converter:

The Catalytic Converter, Fig. 1, is used in the exhaust system to reduce the levels of carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx) entering the atmosphere. The converter permits a faster chemical reaction to take place.
The catalyst in these converters are structured in the form of a honeycomb monolythic composition. The catalyst consists of a porous substrate of a catalytically active inert material.
During operation, all of the exhaust gases flow through the converter where a chemical change takes place. This change causes the temperature inside the converter to be higher than the temperature of the exhaust gases when they leave the engine. Due to this increase in heat, the converter is insulated so that its outside temperature is about the same as a muffler. However, due to its heavier mass, the catalytic converter remains hot much longer than a muffler. The normal operating temperature of the exhaust system is extremely high. Do not attempt to service any part of the system until it has cooled. Extreme caution should be exercised when working around the converter, as its temperature rises to a high level only after a few minutes of engine operation.