What is the purpose of Three Way Catalytic Converter System

The engine exhaust consists mainly of nitrogen (N2); however, it also contains carbon monoxide
(CO), carbon dioxide (CO2), water vapor (H2O), oxygen (O2), nitrogen oxides (NOx), and hydrogen
(H 2) as well as various unburned hydrocarbons (HC). Three of these exhaust components - CO,
NOx, and HC - are major air pollutants, so their emission to the atmosphere must be controlled.
The three way catalytic converter (TWC) , mounted in the engine exhaust system, works
as a gas reactor to convert and reduce the pollutant levels to within legally prescribed limits.
The TWC reduces the air pollutants HC, CO, and NOx. The TWC removes these pollutants from
the exhaust gases by means of a chemical reaction. The remaining gases are transferred to the
muffler.