Valves And Sensors - Aston Martin V8 Vantage Workshop Manual

Fuel Tank and Lines (10.01)
Fuel (10.00)

Valves and Sensors

Fuel System Schematic
Fuel Limit Vent Valve (FLVV)
This valve contains a float which rises to cut off the path for
displaced air when the fuel level rises towards maximum
during fuel filling. This causes a rapid pressure build up in
the tank which triggers the cut-off valve in the fuel delivery
nozzle. This discourages overfilling of the fuel tank.
The FLVV also includes an over pressure relief valve set at
about 2 psi to vent the tank if all other vents fail.
Roll Over Valves
The roll over valves purpose is to vent the highest point of
the tank. If the tank is grossly overfilled (e.g. many clicks over
the normal filler nozzle cut-off), the FLVV will suffer a
hydraulic lock. The roll over vent valve allows venting of the
tank at the highest possible level in this situation.
All three valves allow the tank to breath until it is inverted
when they will close to prevent fuel spill. The fuel level vent
valve controls the fuel height of the tank by creating a
pressure spike inside the tank which shuts of the fill nozzle.
If the vehicle is inverted in an accident, this valve will close
to prevent leakage of liquid fuel.
October 2005 Workshop Manual 10-1-5