Catalytic Converter

The catalytic converter further reduces the carbon monoxide and hydrocarbons content of the exhaust gases. In the catalytic converter the exhaust gases are passed through honeycombed ceramic elements coated with a special surface treatment called a 'washcoat'.

The 'washcoat' increases the surface area of the ceramic elements by a factor of approximately 7000. On top of the 'washcoat' is a coating containing platinum group metals, which is the active constituent for converting harmful emissions into inert by-products. The platinum adds oxygen to the carbon monoxide and the hydrocarbons in the exhaust gases, to convert them into carbon dioxide and water respectively.

A pre catalyst Heated Oxygen Sensor (HO2S) is located ahead the pre catalytic converter. A mid catalyst HO2S is located between the pre and the main catalytic converter or Gasoline Particulate Filter (GPF). Depending of the market specifications the post catalyst HO2S is located on the outlet pipe of the catalytic GPF.

The HO2S are used to monitor the exhaust gases leaving the engine. The Powertrain Control Module (PCM) uses the information from the HO2S to provide accurately measured quantities of fuel to the combustion chambers. The PCM uses the information from the HO2S to minimize the exhaust emissions.

For additional information, refer to: ELECTRONIC ENGINE CONTROLS .