Fuel Injector: Description and Operation

The injector, which is an injection nozzle with solenoid valve, injects fuel based on the injection signal from the ECU. The injectors are installed in the intake manifold at each cylinder and are connected to the delivery pipe. When the solenoid coil is energized, the plunger is attracted. The needle valve, integral with the plunger, is then pulled to the full open position with the plunger and fuel is injected through the open valve. As the injection nozzle opening is fixed and the fuel pressure is also fixed, the amount of fuel injected is determined by the duration during which the needle valve is open, the time which the solenoid coil is energized.