Working Principle Of Exhaust Catalytic Converter

The working principle of an exhaust catalytic converter is as follows: When high-temperature vehicle exhaust passes through the purification device, the purifying agent in the catalytic converter enhances the activity of CO, HC, and NOx gases, promoting certain oxidation-reduction chemical reactions. Specifically, CO is oxidized at high temperatures into colorless, non-toxic carbon dioxide; HC compounds are oxidized at high temperatures into water (H2O) and carbon dioxide; and NOx is reduced into nitrogen and oxygen. These three harmful gases are transformed into harmless gases, thus purifying the vehicle exhaust.

An exhaust catalytic converter is similar to a muffler. Its outer surface is made of a cylindrical structure using double-layered stainless steel sheets. Insulation material-asbestos fiber felt-is placed between the double-layered sheets. The purifying agent is placed inside, sandwiched between mesh partitions. The purifying agent consists of a carrier and a catalyst. The carrier is generally made of aluminum oxide, and its shape can be spherical, polygonal, or a mesh partition. The purifying agent, also known as a catalyst, is what actually acts as a catalyst. Catalysts are typically made of platinum, rhodium, or palladium. Spraying one of these onto the carrier constitutes the purifying agent.