Vent Valve, Function

Vent Valve, Function




1 Compression spring
2 Valve housing
3 Spring cup
4 Bleed valve
5 Valve plate
6 Air admission valve
7 Connection
76 Vent valve
A Connection to activated charcoal canister
B Connection to fuel tank

Fuel tank ventilation
The ventilation valve (4) opens at an overpressure of around 30 to 50 mbar.
The fuel vapors flow to the activated charcoal canister.

Fuel tank aeration
The air admission valve (6) opens at a vacuum of around 1 to 16 mbar in the fuel tank.
Air or fuel vapors are drawn in through the activated charcoal canister.

Refueling
The opening pressure of the vent valve (4) of approx. 30 up to 50 mbar is not achieved if the fuel tank cap is removed. The vent line to the activated charcoal canister remains closed off. This switches off the nozzle more rapidly.