Catalytic Converter Repair - Get an online auto repair estimate
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The catalytic converter is a sophisticated 'after burning' device that is designed to complete the combustion of the exhaust gases that pass through it and is a key component in the vehicle's pollution control system. It is a stainless steel container with an inlet and outlet pipe that looks similar to a muffler and is located in the vehicle's undercarriage.
Inside the catalytic converter is a ceramic monolithic structure that has honeycomb like passages running though it. This structure has several sections called 'beds' that are thinly coated with special rare metals that react with the compounds in the exhaust gases to complete the combustion process thereby cleaning or ‘scrubbing’ the exhaust of the harmful emissions.
The first section of the converter is called the reduction bed and is coated with Rhodium. It is called the reduction bed because its purpose is to reduce the Nitrogen Oxide (NOx) gases back in to harmless nitrogen and oxygen.
The next section of the converter is the oxygen storage bed that is coated with Cerium. Its purpose is to maintain an ideal level of oxygen for use by the rear of the converter. It does this by storing and releasing the oxygen that gets released from the reduction of nitrogen oxide (NOx) in the previous reduction bed. The oxygen is then available to be used in the final oxidizing bed which is coated with Platinum and Paladium. The purpose of the oxidizing bed is to complete the combustion of Carbon Monoxide (CO) by adding oxygen. The oxidizing bed also utilzes oxygen to burn any of the raw Hydrocarbons (HC’s) that still remain in the exhaust gases.
The inside of the catalytic converter operates at very high temperatures. It will not even begin to 'light off' until it reaches 400-600 degrees Fahrenheit and typically runs from 1200-1600 degrees depending upon how hard it is being worked. A rich or 'dirty' running engine can make the converter work so hard that it will actually glow red. This is why there are catalytic converter damaging misfire codes that will illuminate the check engine light and even make it steadily flash under severe misfire conditions.