| Depending on the local air temperature and pressure, fuel vapours form over the reservoir fuel surface. |
| The activated charcoal filter system prevents these hydrocarbon emissions from reaching the air we breathe. |
| Limited amounts of fuel vapours reach the activated charcoal filter, located in the highest point of the tank, through a gravity valve (which closes at a 45° inclination) and the pressure retention valve. |
| The activated charcoal absorbs these vapours like a sponge. |
| While vehicle is moving and the lambda adjustment is active (heated engine), the Magnetic valve I for activated charcoal reservoir -N80- (also known as regeneration valve) is activated by pulses, due to load or speed, by the Engine control unit -J623-. The opening period depends on the input signals. |
| During draining process (activated charcoal recovery), the clean air is absorbed by the ventilation opening, on the activated charcoal filter lower part. The fuel vapours temporarily stored in the activated charcoal and the fresh air are fed for combustion in dosed quantities. |
| The pressure retention valve prevents fuel vapours from coming into the tank when the electromagnetic valve is open and there is vacuum in the intake manifold. This ensures that the activated charcoal filter is primarily drained. |
| With no current supply, the electromagnetic valve is closed (i.e., upon power supply interruption) and the charcoal filter is not emptied. |
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| Hose connections are fastened by spring clamps. |
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| To install spring clamps, we recommend using the VAS 5024A or Standart-type clamp pliers -VW 5162-. |
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