Systems Operation Section
Fuel System
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Fuel System Operation
The fuel supply circuit is a conventional design for
engines that use fuel injectors. The fuel supply circuit
uses a fuel transfer pump to deliver fuel from the fuel
tank to the fuel injectors. The transfer pump is a fixed
displacement gear pump. The fuel transfer pump is
installed to the back of the oil pump.
A fuel priming pump is on the fuel transfer pump to fill
the system. The system must be primed after the
filter changes. The system must be primed after
draining the fuel supply and return manifolds, when
the fuel injectors are replaced.
The fuel flows continuously from the fuel supply
manifold through the fuel injectors. The fuel flows
when either the supply or the fill port in the injector is
not closed by the injector body assembly plunger.
The fuel that is not injected into the cylinder is
returned to the tank through the fuel return manifold.
A pressure regulating valve is installed at the end of
the fuel return manifold. The pressure regulating
valve controls the entire fuel system pressure. This
ensures that the fuel injectors are correctly filled with
fuel.
The mechanically actuated fuel injector system
provides total control of injection timing. The injection
timing is varied to optimize the performance of the
engine.
A speed sensor measures engine speed. A digital
governor regulates the input of the fuel to the engine
so that the actual engine speed matches the desired
engine speed. Engine speed is maintained by the
governor by a speed sensor. The speed sensor is
mounted next to the flywheel gear. The governor
actuator that is controlled by the digital governor for
the required load is connected to the linkage of the
fuel injectors. The fuel is injected into the cylinder at
precisely the correct moment for the most efficient
combustion.
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Fuel Injector Mechanism
The fuel injector mechanism provides the downward
force that is required to pressurize the fuel in the fuel
injection pump. The mechanically operated fuel
injector allows fuel to be injected into the combustion
chamber.
Force is transmitted from the fuel injector lobe on the
camshaft through the lifter to the pushrod. The force
from the pushrod is transmitted through the rocker
assembly and to the top of the fuel injection pump.
The adjusting nut allows setting of the injector timing.
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