TOOL AS-VALVE 2293612 - Caterpillar

Illustration 1 g01799294
Fuel injector and solenoid
Fuel injection occurs when the injector solenoid is energized by the Electronic Control Module (ECM). As the solenoid is energized a magnetic force is generated. The magnetic force opens an internal fuel check valve. Fuel injection begins as the fuel pressure overcomes the pressure that is exerted by the spring force of the check valve. During fuel injection, high pressure fuel from the fuel rail flows into the injector and to the fuel injector nozzle. The needle valve in the tip of the injector is spring loaded. Fuel flows through the fuel passage around the needle valve to the valve chamber. In the valve chamber, the fuel pressure lifts the needle valve away from the seat. The fuel is sprayed through the orifices that are in the tip of the injector. The atomized fuel is injected into the combustion chamber.
Illustration 2 g01799117
Fuel injector tip
The tip of the fuel injector protrudes for a short distance below the cylinder head into the combustion chamber. The fuel injector tip has several small orifices that are equally spaced around the outside diameter. The size of these orifices and the pressure of the fuel determine the degree of atomization of the fuel during fuel injection.