DETROIT DIESEL 53
2.1.1
Fuel
Injector
injectors with the other types of injectors in an
engine.
Each fuel injector has a circular disc pressed into a
recess at the front side of the injector body for
identification purposes (Fig. 5). The identification tag
indicates the nominal output of the injector in cubic
millimeters.
Each injector control rack (Fig. 2) is actuated by a
lever on the injector control tube which, in turn. is
connected to the governor by means of a fuel rod.
These levers can be adjusted independently on the
control tube, thus permitting a uniform setting of all
Fig. 3. Fuel Metering from No-Load to Full.
injector racks.
Load
Figure 4 illustrates the phases of injector operation by
The fuel injector combines in a single unit all of the
the vertical travel of the injector plunger.
parts necessary to provide complete and independent
fuel injection at each cylinder.
The continuous fuel flow through the injector serves,
in addition to preventing air pockets in the fuel
system, as a coolant for those injector parts subjected
to high combustion temperatures.
To vary the power output of the engine, injectors
having different fuel output capacities are used. The
fuel output of the various injectors is governed by the
helix angle of the plunger and the type of spray tip
used. Refer to Fig. 5 for the identification of the
injectors and their respective plungers and spray tips.
Since the helix angle on the plunger determines the
output and operating characteristics of a particular
type of injector, it is imperative that the correct
injectors are used for each engine application. If
injectors of different types are mixed, erratic operation
will result and may cause serious damage to the engine
or to the equipment which it powers.
CAUTION: Do not intermix the needle valve
Fig. 4. Phases of Injector Operation Through
Vertical Travel of Plunger
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