Catalytic Converter: Description and Operation

Oxidation Catalytic Converter






Design
The catalytic converter is composed of a stainless steel housing, a wire mesh and the substrate (ceramic monolith) with the actual catalytic layer. Ceramic monoliths are ceramic bodies containing several thousand small passages. The ceramic is composed of a high temperature-resistant magnesium-aluminium silicate. The monolith is extremely sensitive to stresses and is therefore mounted in the stainless steel housing, embedded in a flexible metal mesh made of high-alloy steel wires.

Coating:
The active catalytic coating applied to the substrate coating consists in the case of oxidation catalytic converters of platinum. Platinum promotes the oxidation of hydrocarbons (HC) and carbonmonoxide (CO). The content of rare metals contained in a catalytic converter is about 1-2 grammes depending on the size and design.








Engine 606.912






Engine 606.962






Engine 606.961


Task
Reducing the pollutant components of carbonmonoxide (CO), hydrocarbon (HC) and particulates (PM=particulate mass).


NOTE: The term oxidation catalytic converter is used by virtue of its property to reduce CO and HC by means of oxidation.


Function
The exhaust gases flow through the catalytic converter and, as a result, come into contact with the rare metal platinum. As a result of oxidation, carbonmonoxide (CO) is converted into carbondioxide (C02) and hydrocarbons (HC) into carbondioxide (C02) and water (H20). As a result of this process, the emitting particulate mass (PM) is also reduced because the hydrocarbons bonded to the carbon (soot) are reduced during postoxidation.