The three-way catalytic converter, also known as the three-way catalytic transformation device (TWC), is the most crucial post-combustion purification device installed in a vehicle's exhaust system.
It can convert harmful gases such as CO, HC, and NOx emitted by car exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. When high-temperature exhaust passes through the purification device, the catalyst in the three-way converter enhances the reactivity of CO, HC, and NOx, promoting specific oxidation-reduction chemical reactions. At high temperatures, CO is oxidized into colorless and non-toxic carbon dioxide; HC compounds are oxidized into water (H2O) and carbon dioxide; and NOx is reduced into nitrogen and oxygen. The three harmful gases are transformed into harmless gases, purifying the car exhaust.