What does a catalytic converter do?

If you are reading this article, chances are you would want to know what does a catalytic converter do? A catalytic converter is a component of the exhaust/emission system. It is responsible to remove harmful substances from the fumes and smoke that may affect the engine’s performance.

But there’s more to the question ‘what does a catalytic converter do’ then its definition. Let this article guide you to find the answer you are looking for about catalytic converters, its functions, and the latest ones available in the market.

The harmful substances present in fumes and smoke

The fumes and smoke that a car emits, contain hydrocarbons, carbon monoxide and nitrogen oxides. These are the major substances that are responsible for air toxicity.

The hydrocarbon molecules are released in the form of unused gasoline. The carbon monoxide molecules are formed during gasoline combustion. Since nitrogen makes up most of the gas in the air, it reacts with oxygen to form nitrogen oxide molecules.

The combustion process occurs when gasoline reacts with the air.

So, what does the catalytic converter do?

Generally, a catalyst helps in the process of some other substance to either be produced, or break down, or convert to something else. The catalyst does not go through any change itself. Its composition remains intact.

The catalytic converter is made up of a muffler-structured large tube. Inside the muffler-structure, there is a temperature-resistant honeycomb made of ceramic. It is structured to fix firmly in the muffler. This honeycomb is coated with a substance that acts as a catalyst.

The substance is a mixture of platinum and palladium, or it may contain alumina and ceria. The coating may consist of gold or rhodium. This honeycomb slows down the bursts of smoke and fumes, giving the catalyst the time to interact with the harmful substances.

The catalyst does not go through any type of chemical change even though it gets very hot. But about 90% of these harmful gases are transformed. The catalyst changes hydrocarbons into carbon dioxide and water vapors. The nitrogen oxide breaks down into nitrogen and oxygen. Meanwhile, the deadly carbon monoxide changes to carbon dioxide.

The tube structure is attached to the end part of the exhaust pipe. The exhaust pipe runs from the engine to the back of the car, curving to the right, at the back of the car. Thus, any smoke that is built up in the engine, and the engine compartment in the front of the car is forced through the exhaust pipe and into the converter before leaving the car.

The types of catalytic converters

Since we have answered ‘what does a catalytic convertor do’ let’s explore its types. There are two main types of converters, including a two-way type and a three-way type

The two-way type

This type of catalytic converter is mostly used for exhaust pipes coming from diesel engines. It performs two different tasks together. It deals with carbon monoxide molecules and it converts the hydrocarbon molecules into carbon dioxide and water.

The three-way type

The three-way type is used in all petroleum-based engines. This type of converter also breaks down nitrogen oxide molecules to nitrogen and oxygen.

The latest catalytic converters extra protection features

The latest converters boost the Hp output of the car’s engine, while ensuring that the engine does not heat up due to combustion. Some converters have oxygen indicators and might let out oxygen from the middle of the muffler. There are converters that can have up to four oxygen indicators, and separate outlets for oxygen.  Some converters come with a 50,000-mile warranty.


There are some US states that have imposed a $10,000 fine on a driver if he does not have a catalytic converter attached to the exhaust pipe. Make sure to get your converter checked if it is working properly to avoid any legal problems.

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