What is the Three-Way Catalytic Converter on a Sedan?

[John]

The three-way catalytic converter on a sedan is the most important external purification device installed in the vehicle's exhaust system. It converts harmful gases such as CO, HC, and NOx emitted from the vehicle's exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. Modern vehicles are all equipped with three-way catalytic converters. Only vehicles produced in earlier years that did not meet the China II emission standards lack this component. Composition of the Three-Way Catalytic Converter: The three-way catalytic converter generally consists of four parts: the shell, vibration damping layer, substrate, and catalyst coating. The shell is made of stainless steel to prevent oxide scale from peeling off, which could block the substrate. The vibration damping layer is composed of gaskets or wire mesh pads, serving functions such as sealing, insulation, and securing the substrate. To prevent damage to the substrate from factors like vibration and thermal deformation, the gaskets are made of expanded mica and aluminum silicate fibers, bonded together with adhesive. The substrate is made of honeycomb-shaped ceramic materials, though many are also made of metal (including stainless steel). The catalyst consists of precious metals such as platinum, rhodium, and palladium, which are sprayed onto the substrate to form the purifying agent.