l       General 

 In order to control automotive emissions, reduce carbon monoxide, smog, and other toxic compounds catalytic converters began to be used on cars in the 1970's. Since that manufacturers have used many methods to control exhaust emissions over the decades, such as exhaust gas re-circulation, containment systems for evaporative emission, on board engine management systems etc., but the single most effective way to reduce exhaust emissions has been the catalytic converter.

l      Three-way catalytic converter 

Catalysts inside of our catalytic converters are precious metals such as platinum, palladium, and rhodium coated on the surface of ceramic honeycomb structures. Chemical reactions take place converting the harmful exhaust gases into harmless compounds when exhaust molecules contact the catalysts. Catalysts reduce the activation energy required by the reactions and increase therefore the possibility for them.

Most modern catalytic converters contain two distinct catalysts: the reduction catalyst and the oxidation catalyst. The exhaust flows through reduction catalyst at first, consists of a ceramic honeycomb coated with platinum and rhodium. In this section, Nox emissions are converted into oxygen and nitrogen. When the exhaust flow then passes through the oxidation catalyst, consists of a platinum and palladium honeycomb, unburned hydrocarbons and carbon monoxide are oxidized into harmless carbon dioxide and water. The oxygen generated by the reduction catalyst further aids this oxidizing.

Main exhaust content：

 l          Carbon monoxide (CO)

 l         Non-methane hydrocarbon (NMHC)

 l         Oxynitride（NOx）

 l         Sulfide（SOx）

The purpose of catalytic converters is to convert harmful hydrocarbons, carbon monoxide, and nitrogen oxides into harmless compounds. We have been trying to produce better and more economic catalytic converters with higher converting efficiency for years. The average efficiency for some chemical reactions under ideal conditions can be read from the following table:

Chemical reactions

Average reduction of polluting emissions at 450°C

up to 95%

up to 95%

up to 30%

N.A.

up to 30%

Our dominate material of ceramic substrate for catalytic converters is porous cordierite, which can be used at temperatures up to 1300℃. Because of its nature of crystallization, chemical composition ,cordierite has extremely low thermal expansion coefficient. A high geometric surface to volume ratio from 0.2 to 0.3 m²/g is achieved through high cell density of 400 CPSI. Other features like low pressure drop, chemical inertness, fast heat up time, and structural stability at high temperatures make our ceramic honeycomb an ideal catalyst substrate media for both oxidation and reduction catalyst.