3-15. FUEL INJECTOR - MAINTENANCE INSTRUCTIONS.
a. The fuel injector is a lightweight compact unit which enables
quick, easy starting directly on diesel fuel and permits the use of a
simple open type combustion chamber. The simplicity of design and
operation provides for simplified controls and easy adjustment.
b. The fuel injector performs four functions:
Creates the high fuel pressure required for efficient injection.
Meters and injects the exact amount of fuel required to handle the load.
Atomizes the fuel for mixing with the air in the combustion chamber.
Permits continuous fuel flow.
Combustion required for satisfactory engine operation is obtained by injecting, under pressure, a small
quantity of accurately metered and finely atomized fuel oil into the cylinder.
d. The continuous fuel flow through the injector:
Prevents air pockets in the fuel system.
Provides a coolant for those injector parts subjected to
high combustion temperatures.
Do not intermix the needle valve injectors with the
other types of injectors in an engine.
e. Each fuel injector has a circular disc pressed into a recess at the front side of the injector body for
identification purposes. The identification tag indicates the nominal output of the injector in cubic
f. Fuel under pressure enters the injector from a fuel manifold. Motion of the rocker arm allows the
injector to release a spray of fuel into a cylinder. A control rack on the side of the injector controls the amount
of fuel being dispensed, and the speed of the