Fuel supply systems in gasoline engines
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Fuel system
The fuel is delivered from the fuel tank by the fuel pump via the feed line with a defined primary pressure to the high pressure pump. The primary pressure is monitored by the fuel pressure sensor. The fuel is delivered by the fuel pump as required. A return line is not required.
Tank-venting system
The tank safety valve is a closed system that is bled via a carbon canister. The carbon in the canister is stored as granules. The large surface of the granules traps the fuel vapor, that occurs in the fuel tank. The carbon canister needs to be refreshed regularly in order to be able to continue to store fuel vapor. This is done by flushing it with fresh air from the intake pipe. This process is controlled by the engine control unit.