Fuel Injector: Description and Operation

Fig. 2 Fuel injector cross sectional view:

The fuel injector nozzles are electromechanical devices that meter and atomize fuel delivered to the engine. The injectors are mounted in the lower intake manifold and are positioned so that their tips direct fuel just ahead of the engine intake valves. The injector body, Fig. 2, consists of a solenoid actuated pintle and needle valve assembly. An electrical control signal from the EEC activates the injector solenoid, causing the pintle to move inward off the seat, allowing fuel to flow. Because the injector flow orifice is fixed and the fuel pressure drop across the injector tip is constant, fuel flow to the engine is regulated by how long the solenoid is energized. Atomization is achieved by contouring the pintle at the point where the fuel separates.