Fuel Injector: Description and Operation

Fuel Injector (Bosch):

PURPOSE AND LOCATION
The fuel injectors deliver a precise amount of highly atomized fuel to each cylinder's intake port. Each injector is positioned at the end of the intake runner and directs fuel at the intake valve.

CONSTRUCTION
Each injector consist of a fuel filter (screen), needle valve, solenoid, magnetic winding and an electrical connector for the ECU. The needle valve solenoid opens when the magnetic winding is energized and closes when without current.

OPERATION
The ECU grounds the electrical circuit to operate the injectors. The air/fuel ratio is controlled by the duration of the "open" (injector is energized) cycle which determines the amount of atomized fuel injected into the intake manifold.

SIGNAL
The injectors are supplied with current as soon as the ignition is turned "ON". The ECU controls the ground connection to operate the injectors.