Three-way catalytic conversion refers to the catalytic process of converting harmful gases such as carbon monoxide, hydrocarbons and nitrogen oxides from automobile exhaust gas into harmless carbon dioxide, water and nitrogen gas through oxidation and reduction, which is mainly realized by three-way catalyst.Three-way catalyst is the most important external purification device installed in the automobile exhaust system, mainly composed of two parts: the carrier and the catalyst coating.The carrier parts are mainly made of porous ceramic materials or alumina, and the main components of the catalyst are precious metals such as platinum, rhodium and palladium and rare earth coatings.

The birth of three-way catalyst is inseparable from the development of the automobile and petrochemical industry.As people find that the increase of octane value can effectively reduce the detonation phenomenon of the engine, the label of gasoline is constantly increasing, and with the increase of combustion temperature in the cylinder, new pollutants - nitrogen oxides begin to appear in the exhaust gas.The photochemical smog event in Los Angeles in 1943 began to arouse people's attention to the problem of automobile exhaust pollution. In order to solve this problem, researchers have racked their brains. Finally, they concluded that they should eliminate pollutants at the source.In 1952, Eugene Houdry, a Frenchman, developed a catalytic converter and registered a patent. In 1975, the United States regulations that all gasoline vehicles must be equipped with catalytic converters.But the catalytic converter is also binary, the main components of the metal platinum and palladium, can be the car exhaust of carbon monoxide and unburned hydrocarbons catalytic oxidation into carbon dioxide and water, but nitrogen oxides are still "at large".In 1981, researchers introduced the metal rhodium in the catalyst, can remove the nitrogen oxides in the exhaust, the three-way catalyst was born.After the birth of the three-way catalyst, countries in the automotive emissions regulations have added the provisions of the gasoline vehicle equipped with three-way catalytic converter, and the three-way catalyst is really popular.

Our country from 1983 began to promulgate the first batch of motor vehicle exhaust pollution control standards.In 2005, the State Environmental Protection Administration announced five new standards for the emission of motor vehicle pollutants.The new standard also means stricter exhaust emission regulations, so the maintenance of the three-way catalyst is also the link that should be paid special attention to in the maintenance of the car.

First of all, the refueling needs to be to the regular gas station, do not be greedy for cheap and choose the oil of unknown origin.Some private oil quality is not guaranteed, which is likely to be mixed with lead, manganese and other impurities, affecting the performance of the three-way catalyst; Secondly, the three-way catalyst should be cleaned regularly, which can effectively reduce the blockage of the exhaust system and improve the fuel efficiency; third, the formal maintenance site should be selected to avoid the precious metal components in the three-way catalyst.