Catalyst Converter: Evaluation as well as How 2-Way and 3-Way Converter Functions

With the passage of the Clean Air Act, auto suppliers were faced with the task of significantly decreasing exhausts, the catalytic converter played a big role in manufacturers fulfilling the new requirement. 

To know about per piece pricing catalytic converters, please follow the link.


  • Allows oxidation of CO, or carbon monoxide, to less harmful CO2, or carbon dioxide.
  • Enables oxidation of HC, or unburned hydrocarbons, to CO2, or carbon dioxide, as well as H2O, or water.

In this layout, exhaust gases are guided to flow with the substratum, having precious metals palladium and platinum, which allow the chain reaction to occur. The exhaust gases boost in temperature as the conversion process happens.

Because of the extreme heat developed by this process, exhaust gases leaving the converter should be hotter than the gases going into the converter. This likewise is the reason why thermal barriers are called for on many devices.

Two-way converters operate fairly efficiently with a lean gas mixture. Ineffectiveness in managing NOx, or nitrogen oxides, resulted in the introduction of three-way converters.


  • Enables decrease of NOx, or nitrogen oxides, to N2, or nitrogen, and O2, or oxygen.
  • Permits oxidation of Carbon Monoxide, or carbon monoxide gas, to less harmful CARBON DIOXIDE.
  • Permits oxidation of HC, or unburned hydrocarbons, to CO2 as well as water.

Three-way plus air converters were used in vehicle emissions systems throughout the late ’70s and very early ’80s.

Inside this converter, there are two substrata. The front, coated with the precious metal rhodium, is utilized to minimize NOx discharges into basic O2 and N2. This procedure is most effective when little O2 exists, abundant combination. That is why it lies upstream of the air tube.

Given that an abundant mixture is high in HC as well as CO, an air pump, as well as tube supply, added O2 to this mix prior to it enters the second substrate.

The second substratum, coated with the precious metals’ palladium, as well as platinum, permits oxidation of HC and Carbon Monoxide to less dangerous discharges WATER and CO2.

This system was not effective, as well as was eliminated in the early ’80s when the existing three-way converter was presented.