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How Catalytic Converters Works to Reduce Environmental Pollution

The number of cars on the road are increasing on a daily basis. Each of this vehicle is a source of pollution. The pollution is especially in the major cities, and this can create a big problem. Consequently, cities have to build new laws that restrict the amount of contamination. Over the years, automakers have made several refinements to the car engines and the fuel system. This move is influenced by the strict laws on pollution.

They have adopted the use of a catalytic converter. The work of this device is to convert harmful pollutants into less harmful emissions even before they get out of the vehicle. Modern cars have an engine that controls the amount of fuel they burn to minimize pollution. The air to fuel ratio is very close. For the gas vehicle, the stoichiometric ratio is about 14.7.1. However, it differs from the idyllic ratio quite a bit when one driving.

The Reduction Process

There are two types of the catalytic converters, which aid in converting the gas from the engine. They include reduction catalyst and an oxidation catalyst. Both of them have a coating of metal catalysts that are platinum or rhodium. They are structures that bring the surface of the catalyst closer to the exhaust stream is created. Therefore, emissions coming out of the vehicle will not be poisonous. The reduction is the first stage of the catalytic converter. It uses rhodium and platinum to help reduce the nitrogen oxide emissions. When nitrogen oxide and nitrogen (IV) oxide molecules contact the catalyst, the catalyst removes the nitrogen atom from the molecule. The nitrogen atom combines with other nitrogen atoms, and they later stick to the catalyst.

The Oxidation Process

The oxidation catalyst occurs at the second stage of the catalytic converter. In this step, the catalyst reduces hydrocarbons by burning them over the palladium and platinum catalyst. Therefore, the catalyst helps in the reaction of the hydrocarbons with the residual oxygen. The gas coming out of the vehicle is non-poisonous after oxidation, and it does not cause any harm to the environment.

Role of the Oxygen Sensor

Then there is the third stage where the conversion of control system takes place. An oxygen sensor is mounted close to the catalytic converter. Thus, the oxygen sensor is closer to the engine than the converter. The sensors tell the computer engine how much oxygen is used up. It adjusts the air to fuel ratio. The whole control system ensures that the engine computer is operating at stoichiometric point.


Finally, you realize that the catalytic converter is efficient in reducing the contamination. However, it can still be improved to increase performance. The biggest disadvantage of the converter is that it only works at moderately high temperatures. When starting a car at a cold temperature, it does not reduce pollution. However, it is clear that the advantages surpass the shortcomings. Therefore, a catalyst plays a significant role in reducing pollution that comes from the motor vehicles.


23 Sep 2017

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