3 WAY CATALYTIC CONVERTERS – STRUCTURE AND PROBLEMS
Recently, clinic one of the most discussed problems – is a problem of environmental protection. Fear of global warming intensifies legislative initiatives to reduce air emissions of toxic substances, thumb such as nitric oxide (NO), look which have an extremely harmful effect on the ozone layer. One of the major air pollutants on a global scale is road transport. For this reason, each year is applying the stricter oversight and restrictions are imposed on automakers.
Today, their products must comply with a number of environmental requirements, which become more stringent from year to year. The design departments of automobile companies are in a continuous race, creating a new system to reduce harmful emissions. This led to one of the key components located in all modern cars – “automotive 3 way catalytic converter”, better known as the catalyst. The catalyst is a component of the exhaust system of a vehicle and is important to reduce emissions of exhaust gases into the atmosphere.
3 way catalytic converters: Design and Operation
The catalyst consists of one or more ceramic or metallic elements made of a plurality of tubes with a wall thickness of 0.2 mm. They are enclosed in a stainless steel and heat-resistant wool. Modern catalysts are made of ceramic based components of cordierite and covered with a very thin layer (20-60 microns) of precious metals, which are essential for the occurrence of a chemical oxidation process. This metal belonging to the platinum group – Pt, Pd, Rh. Platinum is preferred because it provides better oxidation of carbon monoxide and hydrocarbons. In addition, it is resistant to sulfur compounds that are present in the exhaust gases. Using palladium or rhodium (especially rhodium) is useful for dissolution of nitrogen oxides. The action of the catalyst is based on chemical oxidation reactions caused by high temperatures. When the temperature of the catalyst at 250-300 degrees C, is starting the oxidation of harmful gases: CO – carbon monoxide, HC – hydrocarbons and NO – nitric oxide. They neutralized by adding oxygen molecules. Thus, the harmful elements are respectively: CO2 – carbon dioxide, N2 – nitrogen and H2O – water.
The catalytic converter in a cross-sectional
In the petrol cars instead of the ceramic insert, close to the engine is “grid” of metal foil. It is made of stainless steel and is also coated with a thin layer of precious metals. The 3 way catalytic converters are varied and complex, but in general can be divided into two main types – “oxidation” and “ternary catalysts.”
Oxidation catalysts are used in the US since the 70s. They clean more hydrocarbons and carbon monoxide, but cannot cope with nitric oxide.
In modern gasoline vehicles are most often used modern 3 way catalytic converters. They occur three types of oxidation reactions of CO, HC, and NO to produce CO2, H2O and N2.
Calvin Barker is established as a content developer for a range of Internet content networks, who sheds light on a range of industrial equipment subjects such as 3 way catalytic converters and other related areas. A proud traveler of online community and an opinion maker in everything related to the industrial equipment.