TM 5-3895-346-14
FUEL INJECTOR
ENGINE OVERHAUL
filter, the fuel passes through a drilled passage into the supply chamber (that area between the plunger bushing
and the spill deflector, in addition to that area under the injector plunger within the bushing). The plunger
operates up and down in the bushing, the bore of which is open to the fuel supply in the annular chamber by
two funnel-shaped ports in the plunger bushing.
The motion of the injector rocker arm is transmitted to the plunger by the follower which bears against the
follower spring (Fig. 6). In addition to the reciprocating motion, the plunger can be rotated, during operation,
around its axis by the gear which meshes with the control rack. For metering the fuel, an upper helix and a
lower helix are machined in the lower part of the plunger. The relation of the helices to the two ports changes
with the rotation of the plunger.
As the plunger moves downward under pressure of the injector rocker arm, a portion of that fuel trapped under
the plunger is displaced into the supply
Figure 5. Injector Identification Chart.
Figure 6. Fuel Injector Mounting.
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