Catalytic converter

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DodgeCatCon

Catalytic-converter-simulation-velocity-streamlines

US2742437 Houdry Auto Catalyst

Aufgeschnittener Metall Katalysator für ein Auto

Pot catalytique vue de la structure

Catalytic converter is a device used in the exhaust system of an internal combustion engine to reduce the toxicity of emissions from the engine. It converts harmful pollutants in exhaust gas to less harmful emissions by catalyzing a redox reaction (oxidation or reduction). Catalytic converters are widely used in automobiles, but are also utilized in generator sets, forklifts, mining equipment, trucks, buses, trains, and other engine-equipped machines.

History

The development of the catalytic converter is attributed to the work of French mechanical engineer Eugène Houdry in the early 1950s. Houdry was concerned about the effects of air pollution and began researching methods to reduce the harmful emissions from automobile exhaust. The first widespread introduction of catalytic converters was in the United States automotive market in the 1970s as a response to the Environmental Protection Agency's stricter regulation of exhaust emissions. Since then, the use of catalytic converters has become a standard in automotive exhaust systems worldwide.

Function

The primary function of a catalytic converter is to convert harmful pollutants in the car's exhaust gas into less harmful emissions before they leave the exhaust system. The three main pollutants targeted are:

• Carbon monoxide (CO), a colorless, odorless, and poisonous gas, is converted into carbon dioxide (CO2).
• Hydrocarbons (HC) or volatile organic compounds (VOCs), which are a major component of smog, are converted into carbon dioxide (CO2) and water (H2O).
• Nitrogen oxides (NOx), which contribute to smog and acid rain, are converted into nitrogen (N2) and oxygen (O2).

This conversion is achieved through two types of reactions: oxidation and reduction. The catalytic converter contains a core of ceramic or metal honeycombed monolith coated with the catalyst material, usually platinum, palladium, and rhodium.

Types

There are two main types of catalytic converters:

• Two-way catalytic converter: This type primarily focuses on the oxidation of carbon monoxide to carbon dioxide and hydrocarbons to carbon dioxide and water. It was commonly used on vehicles in the United States until 1981.
• Three-way catalytic converter: This type not only oxidizes CO and HC but also reduces NOx emissions. It is the standard in modern vehicles, offering a comprehensive approach to emission reduction.

Environmental Impact

Catalytic converters have played a significant role in reducing the environmental impact of vehicle emissions. By converting harmful pollutants into less harmful gases, they contribute significantly to the improvement of air quality. However, the mining and refining of the precious metals used in catalytic converters, such as platinum, palladium, and rhodium, have their own environmental impacts.

Issues and Maintenance

Catalytic converters can become clogged, poisoned, or physically damaged, leading to a decrease in performance and an increase in exhaust emissions. Lead in gasoline, antifreeze leaks, and oil consumption can poison the catalyst. Regular vehicle maintenance is crucial to ensure the longevity and efficiency of the catalytic converter.

Theft

Due to the precious metals contained within, catalytic converters are a target for theft. The metals can be sold for a significant price on the black market. Vehicle owners are advised to take precautions, such as installing anti-theft devices, to protect their catalytic converters.