General Information

Fuel supply systems for spark-ignition engines.

Fuel System 

The electric fuel delivery pump in the fuel tank generates pressure in the fuel system. This pressure is set at a certain level by the pressure regulator.

Ventilation System 

The ventilation system is a closed system which is vented via an activated carbon filter. The carbon in the activated carbon filter is stored in the form of a granulate. The large surface area of the carbon absorbs the fuel vapors which occur in the fuel tank. The activated carbon filter needs to be regenerated at regular intervals for it to be able to continue absorbing fuel vapours. Regeneration is performed by flushing out with fresh air through the intake manifold. This process is controlled by the engine control unit.

Fuel Supply Systems For Diesel Engines 

Fuel System

The electric fuel delivery pump in the fuel tank supplies fuel to the engine. Two types of high-pressure pump are used for injection into the cylinders.

1. The distributor injection pump. This supplies each cylinder with fuel directly through the respective injector.
2. The high-pressure pump for common rail systems. This generates the necessary pressure in the fuel rail for all injectors.

On common rail systems, a third pump has been incorporated between the high-pressure pump and the electric fuel delivery pump, the so-called inline pump (M57) or gear pump (M67). This pump supplements the fuel delivery pump in the fuel tank when large quantities of fuel are required.

Ventilation System 

Diesel fuel is not easily volatilized, eliminating the necessity for an activated carbon filter. The fuel tank is ventilated directly into the atmosphere.