The three-way catalytic converter is the most important external purification device installed in the car exhaust system. It can convert harmful gases such as CO, HC and NOx from car exhaust into harmless carbon dioxide, water and carbon dioxide through oxidation and reduction.

When the high-temperature automobile exhaust passes through the purification device, the purification agent in the three-way catalyst will enhance the activity of the three gases CO, HC and NOx, and promote certain oxidation-reduction chemical reactions. Among them, the CO is oxidized at high temperature to become non-toxic. Color, non-toxic carbon dioxide gas; HC compounds are oxidized to water (H20) and carbon dioxide at high temperature; NOx is reduced to nitrogen and oxygen. Three kinds of harmful gases become harmless gases, so that car exhaust can be purified. Because this kind of catalyst can simultaneously convert the three main harmful substances in the exhaust gas into harmless substances, it is called catalytic converter universal

The three way catalyst converter reactor is similar to a muffler. Its outer surface is made of double-layer stainless steel sheet into a cylindrical shape. Insulation material-asbestos fiber felt is installed in the double-layer sheet sandwich. Inside, there is a purifying agent in the middle of the mesh partition. The purifying agent is composed of a carrier and a catalyst. The carrier is generally made of aluminum oxide, and its shapes are spherical, polygonal, and net-shaped partitions. Purifiers actually play a catalytic role and are also called catalysts. The catalytic convertors used metal platinum, rhodium and palladium. Spraying one of them on the carrier constitutes a cleaning agent.