Fuel Injector: Description and Operation

Fuel Injector - Cutaway View:

Purpose

Allows PCM to precisely control the amount of fuel injected.

^ Atomizes fuel for more complete combustion.

^ Sprays fuel into intake manifold, above intake ports, in an even, conical pattern.

Operation


The Auto Shutdown (ASD) relay supplies battery voltage to the injector(s).

The PCM controls injector pulse width by supplying the ground path.

Since the injector nozzle is a fixed size and fuel pressure is regulated, the amount of fuel injected changes only when the amount of time the injector is energized per cycle changes. (This period of time is called "injector pulse width".)

When an injector solenoid is energized, the plunger is retracted, lifting needle valve off seat, allowing the pressurized fuel to spray into the intake manifold.

When the solenoid is de-energized spring pressure closes valve.