Porsche 928 1979 Owner's Manual page 74

Activated Charcoal Filter
Vapors from the fuel tank are trapped in a
container filled with activated charcoal. The
filter is connected to the fuel tank vent sys-
tem. This is how it w o r k s :
Fuel vapors pass through the filter and de-
posit hydrocarbons on the surface of the
1 Control valve
2 Vacuum control line
3 Charcoal filter
4 Vent valve
5 Vent line
6 Leakage pipe
7 Expansion chamber
8 Fuel line
9 Fuel return line
10 Throttle plate
11 Intake manifold
12 Air cleaner
13 Fuel injection lines
14 Fuel distributor
15 Fuel filter
16 Accumulator
17 Fuel tank
18 Fuel pumps
charcoal filter element. W h e n the engine is
running, fresh air is drawn in through the
charcoal filter. This fresh air regenerates the
filter and routes the hydrocarbons through
the air cleaner back to the engine, where
they are burned during normal combustion.
1011 12 13 14
Fuel Tank Venting
An expansion chamber for the fuel tank and
vent lines are part of the fuel tank vent sys-
tem. These components prevent fuel from
escaping to the outside at extreme high out-
side temperatures and when the car is driven
or parked at an incline or in any other non-
level position.
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