Car catalyst – what it is

For some time, great attention has been paid to the problem of atmospheric pollution: for this reason the car catalyst was invented years ago . Here’s how it works.

Car catalyst – what it is

Car catalyst

The problem of atmospheric pollution is faced by both governments and car manufacturers: by now all cars have been equipped with devices created to minimize all the negative and polluting effects deriving from combustion.

The modern catalysts are devices designed specifically to reduce CO emissions, VOC and NOx : To obtain this goal, include a reduction system and an oxidation, both formed from a ceramic structure in turn covered by a metal part (platinum, rhodium and / or palladium).

The catalyst is therefore one of the main elements that allow the reduction of vehicle emissions , which is usually installed inside the muffler : visually it appears as a swelling of the exhaust manifold.

Car catalyst: how it works

The car catalyst, also known as the catalytic converter , is an indispensable element of the exhaust system to ensure the maximum reduction of gas toxicity. To do this, it recovers nitrogen oxides and uses oxygen for the post-combustion of carbon monoxide and unburned hydrocarbons.

To understand how a catalyst works, it is good to know at least broadly what a catalytic process is, that is an accelerated chemical reaction generated by a certain chemical element (catalyst, in fact).

With the passage of time and use, the car catalyst can lose its effectiveness and therefore its reaction can become slower, thus affecting its work of “purification” of the exhaust gases from pollutants.

Types of car catalysts

There is no single type of catalyst: there are catalytic modules designed to be added to the exhaust system and the classic catalytic converters (exhaust manifolds with catalyst).

The main differentiation is based on the operation which varies according to the fuel used:

  • diesel– reducing action that transforms NOx into nitrogen and oxygen
  • petrol– oxidizing action with palladium-based converters (two-way or bivalent, but also trivalent (three-way)

Some catalysts also use a lambda probe to determine the amount of oxygen and unburned fuel present in the exhaust gases and to maintain an optimum operating speed.


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