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Working principle of catalytic converters

Views: 1178     Author: Site Editor     Publish Time: 2023-05-16      Origin: Site


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When it comes to the catalytic converter, car enthusiasts know that it is installed in the car exhaust system parts, with the role of exhaust gas purification, but its working state and the principle of what exactly, few people understand, do not think that these theories are not important, in fact, only after we understand a part from all sides, in order to buy more suitable, more desirable auto parts products.


So, let's start this issue of science.

The working principle of catalytic converters

Car combustion engine in the process of combustion, will produce a lot of high-temperature exhaust gas, exhaust gas is mainly carbon monoxide, hydrocarbons and nitrogen oxides of these gases, these harmful gases once untreated emissions into the air, will not only cause environmental gaseous pollution, but also due to harmful substances exceed the standard lead to the vehicle can not pass the annual inspection.

As we mentioned in the previous article, the core of the catalytic converter lies in the carrier, because the carrier will be coated with a layer of precious metal catalysts, these precious metals are platinum (Pt), rhodium (Rh), palladium (Pd), which can enhance the activity of CO, HC and NOx three gases, in high-temperature conditions can also promote the three gases under certain redox reactions.

Among them, CO is oxidized to colorless, non-toxic carbon dioxide gas at high temperature; HC compounds are oxidized to water (H20) and carbon dioxide at high temperature; NOx is reduced to nitrogen and oxygen.

Thus, the harmful gases are transformed into harmless substances, and the car exhaust is thus purified.

It is worth mentioning that among the many carriers, the most popular among car enthusiasts is the honeycomb-shaped cylindrical ceramic carrier because this design actually greatly increases the catalytic reaction area, ensuring that harmful gases can be quickly and thoroughly completed purification.

Extending the life of the catalytic converter from the working principle


In fact, there are many factors that affect the service life of the catalytic converter, next we will list a few precautions related to the working principle, we must avoid the wrong use in the daily use of the car.

① Reject poor quality fuel

Precious metal catalysts are very sensitive to elements such as sulfur, lead, phosphorus and zinc. Sulfur and lead come from gasoline, phosphorus and zinc from lubricating oil, these four substances and their combustion in the engine to form oxide particles are easily adsorbed on the surface of the catalyst, so that the catalyst cannot contact with exhaust gas, thus losing its catalytic effect.

② Will the precious metal catalysts on the carriers be consumed over time?

No, they will not. Although the carriers are coated with precious metal catalysts, they do not actually participate in any redox reactions, they only serve to enhance the activity of the exhaust substances and speed up the reaction rate, so they will not be consumed by the long working hours of the catalytic converters.

③ Will the exhaust gas temperature affect the effectiveness of the catalytic converter?

Yes, the catalytic converter at room temperature does not have catalytic ability, the precious metal catalyst must be heated to a certain temperature to play a catalytic role, usually the minimum working temperature of the converters is 200℃, and the active temperature of the converters is 400-800℃. If the ignition time is too long or the ignition sequence is wrong, the unburned gas mixture will enter the catalytic converter and make the exhaust temperature too high, which may cause the catalytic to fall off or the carrier to break, affecting the catalytic converter effect.



The working principle of the catalytic converter is not complicated, but it does play a vital role for exhaust gas purification. In addition to the daily use, we should maintain good habits, but also regularly replace the three-way catalytic converter to ensure that the three-way catalytic converter is always intact and can operate normally.

GRWA's catalytic converters are with EPA certification and have been exported to the US, Australia and other countries for a long time, fully meeting the emission standards of various countries, and the quality of the product has been approved by car enthusiasts around the world for many years.

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