New Generation N62 Engine
Chapter 6 P.4
Course Contents/Background Material
© BMW AG,
Service Training
The following filler neck measures prevent the escape of fuel
vapours during refuelling:
A spring-loaded cap locks the filler neck from the outside, even
if the fuel filler cap has been opened. The filler neck is designed
so that the incoming fuel functions like a venturi tube during
refuelling and also draws external air into the tank so that no fuel
vapours can escape during this stage either.
The tank pressure must not exceed the pump nozzle cut-out
pressure as a result of the extra air flowing into the tank, even at
the maximum delivery rate. This could otherwise cause the
pump nozzle to cut-out early.