Catalytic Converter: Description and Operation

Purpose
Two separate three-way catalytic converters are used to reduce CO, HC, and NOx emissions. For efficient operation, the warm up three way catalytic converter is placed close to the exhaust manifold so that it will heat up quickly and purify exhaust gas efficiently when engine runs at idle.

Operation
The three-way catalytic converters reduce CO and HC, emissions through oxidation and NOx emissions by chemical reaction.




(1) Before the engine is warmed up, when large amounts of CO and HC are created, the three-way catalytic converter 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 catalytic converter 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, additional air to the three-way catalytic converter is cut off, and the first and second ternary stages of the catalyst are used.




Construction