Weifang 495 Operation And Maintenance Manual page 77

During the operation, the feed pump draws .fuel from fuel tank
thro'ugh the cock and
ftlel
itl1et pipe and delivers it into the fuel fil-
ter~
After being filtered, the fuel flows
i11tO
the upper housing of
the injection pump. Then ,depending on the load of the engine, the
pump element controlled by the pump control rod delivers.1 certain \
quantity.of fuel through the delivery valve
~nd
fuel injection pipe
to the injector. When the pressure of 11768KPa inside the injection
system is built up, the needle velve
will
be lifted opening and the
fuel will be atomized and injected into the combustion chamber to
burn with the charged air. The fuel leaking out from the
c1ea~ance
between the needle valve and nozzle - body will return to the
fuel
tank through the leak -off pipe on'the top of the injector.
~
.
T-l1e
amourlt of· fuel _fed into the injection pump by the feed
pllmp is greater than that needed
by
the engine in operation, The
surplus fuel will flow back to the feed pump through the check
valve so that the fuel will circulate in the upper housing of the in-:
jection pump constantly to prevent it from air trapped inside.
1). Construction of Main Components in Supply System
( 1) Air Cleaner
The diesel engine is provided with different air cleaner accord-
ing to the various applications.
Model 495 diesel engine is provided with a model
t<
2007 air
cleaner (Fig- J.
7)
Model 495 diesel engine draws in air of" 200m
3
per hour ap-
. proximately- If the dust in air is permitted entering the cylinder to-
gether with the air, then the piston ring, the piston and the cylin-
der liner will be worn out in a short time, The function of an air
cleaner is just to filter the air before it enters the intake manifold.
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