Porsche 2007 Cayenne, Owner'S Manual

Page: 305 / 428

Maintenance and Car Care
305
Fuel Evaporation Control
Fuel tank venting
The evaporation chamber and the carbon canister
prevent fuel from escaping to the atmosphere at
extreme high outside temperatures, when driving
abruptly around curves and when the car is parked
at an incline or in any other nonlevel position.
Vapor control system and storage
When the fuel tank is filled, vapors are collected in
the evaporation chamber by a vent line leading the
vapors to the carbon canister where they are
stored as long as the engine does not run.
Purge system
When the engine is running, the fuel vapors from
the canister will be mixed with fresh air from the
ambient air of the canister. This mixture will be di-
rected to the intake air housing by the tank vent
line, mixed with the intake air and burned during
normal combustion.