Fuel Injector: Description and Operation

Fuel Injector Cross Section:

DESCRIPTION
The fuel injector is an electromagnetic type injection nozzle which injects fuel in the Throttle Body Fuel Injection (TBI) unit bore according to the signal from the Powertrain Control Module (PCM).

OPERATION
When the solenoid coil of the fuel injector is energized by the PCM, it becomes an electromagnet and attracts to the plunger. At the same time, the needle valve which is incorporated with the plunger opens and the fuel injector, which is under fuel pressure, injects fuel in conic dispersion. As the stroke of the needle valve of the fuel injector is set constant, the amount of fuel injected at one time is determined by the length of time during which the solenoid coil is energized (injection time).