Different Types of Catalytic Converters and Where They are Used

July 15, 2020

Any sort of diesel engine needs a properly functioning catalytic converter in order to reduce dangerous emissions and run effectively. However, different engines require different converters. If you’ve ever wondered what is a 3 way catalytic converter or any similar question, you can find the answers below. This guide will detail the difference between 2 way, 3 way, and 4-way catalytic converters, allowing you to learn more about this important component and how each one works with engines to make them more efficient.

2-Way Catalytic Converters

A 2-way catalytic converter is the simplest and oldest type of this component available. This type of converter can convert two types of toxins into non-harmful emissions. First, it adds oxygen to carbon monoxide, converting it to carbon dioxide. Second, it adds oxygen particles to burned hydrocarbons, converting them to carbon dioxide and water.

Their weakness is that they cannot control nitrogen emissions, which makes them less effective in modern engines. Recent market research recommends the use of a 3 or 4-way catalytic converter for most new engines.

Despite the age of this type of catalytic converter, the 2-way converter is still in use in many diesel engines, where controlling the output of carbon monoxide and burned hydrocarbons are of particularly high importance. In gasoline engines, the 2-way catalytic converter has been out of use for almost 40 years due to its inability to properly convert nitrogen oxides.

This is an example of why having the right tool for the right engine is of particular importance. While a 2-way converter can help a diesel engine a great deal, you need a 3-way converter for gasoline engines and many other modern pieces of machinery.

3 Way Catalytic Converters

Most engines now use 3-way catalytic converters, which do the job of their 2-way predecessors and then some. Like the 2 way converter, a 3-way catalytic converter reduces the emission of carbon monoxide by converting it to carbon dioxide and burned hydrocarbons by converting them into carbon dioxide and water.

Furthermore, the 3-way converter has the additional function of converting nitric oxide into nitric dioxide by adding extra oxygen to the emission. The converter performs all three tasks at the same time, thus scrubbing exhaust at an almost instantaneous rate to make sure that the emissions are as clean as possible.

You can find a 3-way catalytic converter in most modern engines. Although some diesel engines still use 2-way converters, an increasing number of emissions standards also require the control of nitric oxide. Since 1981, 3-way catalytic converters have been the standard in all gasoline-powered engines. While the even more efficient 4-way catalytic converter is now available with some engines, it has not yet fully replaced the 3-way model.

4 Way Catalytic Converters

Both 2 way and 3-way catalytic converters require the use of a diesel particulate filter to stop the emission of small toxins known as particulates from leaving the engine with the exhaust. These particulates are especially dangerous if breathed in, making them a health and safety hazard in addition to their existing environmental impact.

As engineers work to control particulates better, they have developed the 4-way catalytic converter as a way of stopping particulate emissions. The 4-way converter provides all the same essential tasks that a 3-way catalytic converter does, but goes the extra mile of also “scrubbing” the exhaust of particulates at the same time.

4 way converters are still somewhat new on the market. Researchers and engineers are currently at work making sure that they can maximize the efficiency of these converters without sacrificing engine function. As such, they are mainly found in newer model engines.

Engines that have a particularly high volume of particulates in their exhaust, such as large commercial diesel vehicles, are most likely to sport a 4-way converter. As the cost of this component decreases and research leads to even more efficiency, it is possible that the 4-way catalytic converter might get more of a foothold in the marketplace moving forward.

Each catalytic converter, be it 2 way, 3 way, or 4 way, has a niche in the modern market. It is essential that any engine has a functioning and well-maintained catalytic converter of the proper type in order to function at maximum efficiency. If an engine starts running rough or seems to produce more acrid than normal exhaust, check the catalytic converter to make sure it is functioning properly.

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