ELECTRONIC FUEL INJECTION (EFI)

Electronic Fuel Injection works on the some very basic principle. This system can be divided into three basic sub-system. These are the fuel delivery system, air induction system and the electronic control system.

The Fuel Delivery System:

• The fuel delivery system consist of the fuel tank, fuel pump, fuel injector, fuel delivery pipe (fuel rail), fuel injector, fuel pressure regulator and fuel return pipe.
• Fuel is delivered from the tank to the injector by means of an electric fuel pump. The pump is typically located in or near the fuel tank. Contaminants are filtered out by a high capacity in line fuel filter.
• Fuel is maintained at a constant pressure by means of a fuel pressure regulator. any fuel which is not delivered to the intake manifold by the injector is returned to the tank through a fuel return pipe.

 Air Induction System:

• The air induction system consists of the air cleaner, air flow meter, throttle valve, air, intake chamber, intake manifold runner, and intake valve.
• When the throttle valve is opened, air flows through the air cleaner, through the air flow meter, past the throttle valve and through a well tuned intake manifold runner to the intake valve.
• Air delivered to the engine is a function of driver demand. as the throttle valve is opened further, more air is allowed to enter the engine cylinders.

 Electronic Control System:

• The electronic control system consists of various engine sensors, electronic control unit (ECU), fuel injector assemblies and related wiring.
• The ECU determines precisely how much fuel need to delivered by the injector by monitoring the engine sensors.
• The ECU turn the injectors on for a precise amount of time, referred to as injection pulse width or injection duration. To deliver the proper air/fuel ratio to the engine.