Oxygen sensors and three-way catalysis

What is the use of three-way catalyst and oxygen sensor?

 

The pollutants emitted by automobiles mainly include HC (hydrocarbons), NOx (nitrogen oxides), CO (carbon monoxide) and particles with incomplete combustion.  Among them, hydrocarbons, nitrogen oxides and carbon monoxide are the traditional "big three-way", which is why the three-way catalyst is called "three-way catalyst".  Three-way catalytic converter is actually a porous ceramic body formed and sintered. Its surface is added with catalytic elements such as platinum, rhodium and palladium, which can enhance the activity of hydrocarbons, nitrogen oxides and carbon monoxide and promote it to complete oxidation-reduction reaction as much as possible.  In which carbon monoxide and hydrocarbons will be converted into carbon dioxide and water after oxidation under high temperature conditions, while nitrogen oxides can be reduced into nitrogen and oxygen under high temperature conditions.  Oxygen sensor was born in Germany Bosch Company in 1976. It uses its unique electrochemical reaction principle to detect the oxygen content in the exhaust gas of the engine. ECU continuously judges whether the amount of fuel injected before the fuel injection nozzle is more or less according to the continuous detection result of oxygen sensor, and continuously adjusts the amount of fuel injected so that the engine cylinder can achieve the goal of excellent combustion under different rotating speeds and power output conditions as far as possible.