2.1.1
FUEL Injector
DETROIT DIESEL 53
Figure 4 illustrates the phases of injector operation by the vertical
travel of the injector plunger. 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.
Fig. 3 Fuel Metering from No-Load to
Full-Load
CAUTION: Do not intermix the needle valve 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 injector
racks.
The fuel injector combines in a single unit all of the parts necessary
to provide complete and independent fuel injection at each
cylinder.
Fig. 4 Phases of Injector Operation
Fig . 5 Injector Identification Chart
Through Vertical Travel of Plunger
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