Fuel Delivery and Air Induction: Description and Operation

Fuel System:

PURPOSE
The function of the fuel metering system is to deliver the correct amount of fuel to the engine under all operating conditions.

OPERATION

Fuel Injection
The Engine Control Module (ECM) controls fuel delivery system during normal driving conditions. Intake manifold is used only to let air into engine. Fuel is injected by separate injectors, into all cylinder inlet ports at the same time once every engine revolution. Using this method two injections of fuel are required to produce the charge for each combustion cycle.

Fuel Delivery
Fuel is pumped by an electric pump mounted inside fuel tank, through a fuel filter, to fuel rail.

Fuel rail is attached to top of intake manifold and supplies fuel to all injectors. Fuel is recirculated through rail continually while engine is running. This removes air and vapors from fuel as well as keeping it cool.

Fuel Pressure
Fuel pressure regulator is mounted on fuel rail and maintains a pressure differential across injectors under all operating conditions.

Refer to COMPUTERS AND CONTROL SYSTEMS for more information on fuel control.