16 00 Functional description for general fuel supply systems
Gasoline engine fuel supply systems
Fuel system
The fuel pump in the fuel tank generates pressure in the fuel system, which is set by the electronic pressure control valve to a certain level.
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.
Diesel engine fuel supply system
Fuel system
The fuel pump in the fuel tank supplies the engine with fuel. Two types of high pressure pump are used for direct injection.
- The distributor-type injection pump. This supplies each cylinder directly with fuel via individual injector nozzles.
- The high pressure pump for the common rail systems. This generates the required pressure in the injector pipe for all injector nozzles.
With common rail systems another pump (inline pump, M57/geared pump, M67) is connected between the high pressure pump and the fuel pump. This pump aids the fuel pump in the fuel tank during times of high fuel requirement.
Tank-venting system
Diesel fuel is slow-evaporating, therefore no carbon canister is required. The fuel tank is bled directly into the atmosphere.