Fuel Injector: Description and Operation

Fig. 1 Fuel Injector Circuit:

DESCRIPTION
The Fuel Injectors are solenoid operated valves installed in the Intake Manifold.

OPERATION
When the solenoid coil is energized the plunger is retracted. The needle valve that is attached to the plunger is pulled to the full open position and fuel is injected through the valve. When the solenoid is de-energized, spring pressure closes the valve. Since the injection nozzle opening is a fixed size and the fuel pressure is also fixed, the injection amount is determined by the duration time which the needle valve is open.