Saturday, August 1, 2009

catalytic converters or cat

Untitled Document

Disgusted by black, noxious fumes coming out of your vehicle? That smoke is fouling
the air you breathe, and by the way, poisoning not only yourself but also your
loved ones. And it could also mean frequent emissions tests, as mandated by various
state laws and the federal Environmental Protection Agency (EPA).

You can solve that problem by installing catalytic
into your vehicle. A catalytic
(also known as catcon or cat) is a device that turns harmful exhaust
gases like nitrogen oxides, carbon monoxide and unburned fuel into basic molecules
like nitrogen, oxygen, carbon dioxide and water. "Cats" reduce the
toxicity of these emissions from your internal combustion engine. This way,
these gases can no longer cause damage in the environment, thus making you safer
and healthier.

Motor engines try to regulate the air:fuel ratio to 1:14.7. Meaning, for every
pound of fuel to be burned, the engine needs 14.7 pounds of air to do the job.
But in reality, when driving the air-fuel ratio in your engine varies from lean
(an air-to-fuel ratio higher than 14.7), and other times the mixture can be
rich (an air-to-fuel ratio lower than 14.7).

Because of these non-ideal conditions, the burnt fuel can actually produce other
kinds of emissions like:

* Carbon monoxide - a poisonous gas that is colorless and odorless

* Hydrocarbons or volatile organic compounds - produced mostly from unburned
fuel that evaporates

Sunlight breaks these down to form oxidants, which react with oxides of nitrogen
to cause ground level ozone (O3), a major component of smog.

* Nitrogen oxides - contributes to smog and acid rain, and also causes irritation
to human mucus membranes.

The catalytic
works by:

1.Reduction of nitrogen oxides to nitrogen and oxygen.

2.Oxidation of (non greenhouse gas, but toxic) carbon monoxide to less harmful
(greenhouse gas) carbon dioxide.

3.Oxidation of unburnt carcinogenic hydrocarbons to carbon dioxide and water.

Several components make up the standard catalytic converter. These are:

1.The core or substrate. The core is made up of a ceramic honeycomb, which
provides support to the catalyst.

2.The washcoat. This is a mixture of silicon and aluminum. This forms with the
core, a rough, irregular surface which has a large surface area. The large surface
area gives more places for the catalyst to bind. The catalyst is first suspended
to the washcoat before being applied to the core.

3.The catalyst. Tis is usually a precious metal, either platinum, palladium
or rhodium. Platinum is most widely used but is the most expensive. Either palladium
or rhodium is substituted for it. Platinum and rhodium are used as reduction
catalysts, while palladium and platinum are oxidation catalysts.

One downside of having catalytic
is that it becomes ineffective in the presence of lead, which
leads to catalyst poisoning. Catalyst poisoning occurs when a substance in the
engine exhaust coats the surface of the catalyst, preventing further exhaust
access to the catalytic materials. To avoid it, vehicles with catalytic
are run using unleaded fuel.

help protect lessen the emissions brought about by the burning
of fossil fuels. Having one installed is doing your share in protecting our
environment. In the end, you are also protecting yourself and your loved ones.

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