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All about exhaust systems

An exhaust system consists of tubing used to guide exhaust gases away from the engine end emit them to the environment. Modern exhaust systems usually include an exhaust manifold, a catalytic converter, which turns the harmful emissions of the internal combustion engine into non-toxic gases, and a silencer.

A catalyst in the catalytic converter causes the harmful gases to undergo a chemical reaction. This causes the carbon monoxide, unburned hydrocarbons and oxide of nitrogen to become hydrogen, nitrogen and water. Introduced in 1975 in the USA, catalytic converters pay an essential role in preventing environmental pollution from vehicle emissions. However, catalytic converters do cause more fuel to be consumed and also product carbon dioxide, which is considered to be a cause of global warming.

The silencer consists of a series of passages and chambers lined with fiberglass wool. It may also have resonating chambers where opposing sound waves cancel each other out. While cars have the silencer mounted lengthwise at the rear, large trucks may have the silencer mounted vertically behind the cab or crosswise beneath the cab.

It is possible to significantly improve engine performance through the installation of after-market exhaust systems that have been tuned for that purpose. These are, however, quite expensive as they require the replace of a large portion of the exhaust. In four-stroke engines, power is increased by reducing the back pressure of the exhaust. Another option is ceramic coating which reduces heat loss in the exhaust and lessens back pressure. It also lowers the intake manifold temperature, resulting in increased power.

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