Catalytic Converters: Why They Are So Important

You’ve probably heard of a catalytic converter but you may not know what the device actually does.

Learn all about why these devices are required in cars and how they work.

Why We Need Catalytic Converters?

Most people are aware that cars produce carbon dioxide. While the hope is that water and carbon dioxide are the only products of combustion, this only happens in a perfect world. Due to fluctuations in the fuel to air ratio, other extremely harmful pollutants are created. These pollutants include: carbon monoxide, nitrogen oxides, and hydrocarbons. So, how to get rid of these pollutants?

One way is to make a more efficient engine, which would make perfect combustion more feasible. Although engine technology has improved, the hazardous pollutants are still present in the exhaust and that’s where the catalytic converter comes in to help.

world without catalytic converter

How it works?

Catalytic converters do what their name states, they catalyze reactions. For those of us that aren’t knowledgeable in chemistry, this means that the catalytic converter provides a surface which inhibits a reaction. The catalytic converters in cars convert the previously listed hazardous pollutants to less harmful chemicals.

Catalytic converters must also be very efficient and provide maximum space for the catalyzed reactions to occur. This is especially important because the metals (palladium, rhodium, and platinum) that make up converters are extremely expensive. There are currently two designs for catalytic converters: honeycomb and ceramic beads. Honeycomb Catalytic Converter is by far more popular.

As for how the converter actually works, there are two stages. The reduction catalyst is the first stage and removes nitrogen oxides. In order to do this the catalyst breaks the nitrogen atoms from the nitrogen oxides and then oxygen and nitrogen gas are created. The second stage is the oxidation catalyst. In order to remove carbon monoxide and hydrocarbons, the catalyst oxidizes the pollutants with oxygen. This process does create carbon dioxide, however carbon dioxide is actually less harmful than the contaminants that are catalyzed.

Two-way Versus Three-way Converters

There are two types of catalytic converters. They are two-way and three-way converters. The difference is the three-way containing an oxygen sensor. The oxygen sensor reads the percentage of oxygen present in the engine’s effluent gases. It then adjusts the amount of air going into the engine, attempting to keep the ratio of fuel to oxygen in the correct proportion and still have oxygen left to run the catalytic converter properly.

Catalytic Converter Maintenance

Now you know about your catalytic converter, but how do you take care of it.

First, the average life for a catalytic converter is 100,000 miles (160,000 km). You should then consider either getting your converter regenerated or replaced. Regenerating a catalytic converter is essentially just cleaning it.

When you’re doing a catalytic converter maintenance another point that cannot be stressed enough is that you should never use leaded fuel. The lead diminishes the effectiveness of the catalysts.

Keep in mind that the one shortcoming of the catalytic converter is that it operates best at high temperatures. Therefore, when you first turn on your car the catalytic converter is not operating at its best and is especially a problem for diesel engines which run cooler than petroleum engines.

In an attempt to fix the temperature issue,car manufactures placed the catalytic converter closer to the engine. However, if it too close, the extreme heat may harm the converter. This led to the device being placed under the front passenger seat.


We hope after learning about catalytic converters and how they help keep the air clean

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