Catalytic Converter: Description and Operation

GF49.10-P-2010MCU Three-Way Catalytic Converter, Component Description








1 Three-way catalytic converter

Location
The three-way catalytic converter is located on the rear end of the vehicle, behind the bumper.

Task
The three-way catalytic converter cleans exhaust gases coming from the engine and reduces the noise emissions.

Design
The catalytic converter mainly consists of a ceramic monolith. Ceramic monoliths are ceramic bodies through which pass several thousand small passages. The exhaust gas flows through these passages. The ceramic consists of high temperature-resistant magnesium aluminum silicate.
The monolith, which is extremely sensitive to voltages, is embedded in an elastic wire mesh made of high-alloy steel wires and fitted in a double-walled stainless steel housing.
Ceramic monoliths require a substrate made out of aluminum oxide which increases the effective surface of the catalytic converter. The active catalytic layer coated on the substrate is available in three-way catalysts primarily out of platinum and rhodium.
Platinum accelerates oxidation of the hydrocarbon and carbon monoxide.
Rhodium accelerates reduction of nitrogen oxides.











Function
Exhaust gases flow through the catalytic converters and hence come into contact with the rare metals, platinum and rhodium.
- Oxidation causes carbon monoxide to be converted to carbon dioxide and hydrocarbons into water and carbon dioxide.
- The nitrogen oxide is converted through reduction into nitrogen and carbon dioxide.

The remaining oxygen content in the exhaust is a crucial factor in the conversion of pollutants.
This is determined by the lambda control and maintained at Lambda = 1 under normal operating conditions.