Catalytic Converter: Description and Operation

Description
Two separate three-way catalysts are used to reduce CO, HC, and NOx emissions. For efficient operation, the warm-up three-way catalyst is placed close to the exhaust manifold so that it will heat up quickly and purify exhaust gas efficiently when engine runs at idle.
The three-way catalysts reduce CO and HC, emissions through oxidation and NOx emissions by chemical reaction.

- Warm-up three-way catalyst: Metal Type
- Three-way catalyst: Monolythic Type




Operation
1. Before the engine is warmed up, when large amounts of CO and HC are created, the three-way catalyst is supplied port air and uses both the first and second stages as the oxidation catalyst.
2. In the normal driving range, the three-way catalyst is supplied split air and uses the first stage as the ternary catalyst and second stage as the oxidation catalyst.
3. During high-speed driving, an additional air to the three-way catalyst is cut off, and the first and second stages are used the ternary catalyst.