16 00 Functional description for general fuel supply systems

WARNING: This page does not describe the selected car, but rather 24 other vehicles, including the 2015 BMW Alpina B7L xDrive, 2015 BMW Alpina B7 xDrive, 2015 BMW 750i xDrive, 2015 BMW 750i, and 2015 BMW 750Li xDrive. However, it is still accessible from the selected car via links, so may be relevant.

Fuel supply systems in petrol engines

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 vapour, that occurs in the fuel tank. The carbon canister needs to be refreshed regularly in order to be able to continue to store fuel vapour. This is done by flushing it with fresh air from the intake pipe. This process is controlled by the engine control unit.

Diesel engine fuel supply systems

Fuel system

The fuel is delivered from the fuel tank by the fuel pump via the feed line to the high pressure pump. The fuel pump delivers more fuel than the engine requires. A return line is required.

Tank-venting system

Diesel fuel is slow-evaporating, therefore no carbon canister is required. The fuel tank is bled directly into the atmosphere.