Activated carbon filter

Activated carbon filter:
In the image below is a fuel tank shown together with the activated carbon filter. The activated carbon filter ensures that the HC emissions (fuel vapours) do not end up in the outside air. This filter sucks the fuel vapors out of the tank and filters it through the special absorption carbon material. After the fuel vapors have been filtered, they are discharged to the outside air or to the engine's intake system. The vapors are mixed with the intake air and then burned. In this way the fuel vapors are removed as cleanly as possible.

The activated carbon filter can be mounted near the fuel tank, but sometimes it is also located under the hood. On some cars where the filter is mounted under the hood, an audible ticking sound can sometimes be heard. The moment the element ticks, the activated carbon filter is in operation.