Engine Fuel System - Allis-Chalmers HD-9 Service Manual

SECTION II-ENGINE FUEL SYSTEM
Topic Title
Description of System ............ .
Topic No.
1
Checking Fuel Supply System ...... .
2
Fuel Tank and Drain Elbow ........ . 3
Fuel Filters . . . . . . . . . . . . . . . . . . . . . . .. 4
Fuel Pump. . . . . . . . . . . . .. . . . .. . .. 5
Fuel Injectors ................... 6
Injector Copper Tubes. . . . . . . . . . . . . 7
Fuel Manifolds . . . . . . . . . . . . . . . . . . . 8
1. DESCRIPTION OF SYSTEM
The engine fuel system consists of the fuel tank,
first stage fuel filter, fuel pump, second stage fuel
filter, injectors, fuel lines, and fuel pressure gage.
The fuel is drawn from the bottom of the fuel tank
and through the first stage fuel filter by the fuel
pump. The pump then circulates the fuel under
pressure through the second'stage fuel filter, fuel
inlet monifold on the right side of the cylinder
head, and then through the injectors. As the fuel
enters each injector, it passes through a small
porous metal filter in the injector body. The amount
of fuel required by the engine is injected into the
cylinders by the injectors; surplus fuel, not required
for combustion, leaves eoch injector through an-
other porous metal filter, enters the return fuel
manifold and is returned to the fuel tank. A pres-
sure of 20 to 55 pounds is maintained within the
fuel system by a restricted fitting located in the
rear of the return fuel manifold. The continuous
circulation of fuel helps to cool the injectors and
eliminates the possibility
of
air pockets in the fuel
system.
INJECTOR FUEl LINES
RETURN FUEL MANIFOLD
FUEl TANK
DRAIN COCK
~~,
." ...
"
;:
"
" "
" "
"
"
"
.,
RETURN TO TANK
~::::==~=:9
FUEl TANK SHUT.OFF VALVE
INJECTORS
O--o-O~o
2nd STAGE FUEL FILTER
\
(
\
INLET FUEL MANIFOLD
u
ht STAGE FUEL FILTER
'---_ _ _ _ _ _ _ _ _ _ _ _ fig. I-Schematic ruel Flow Diagram _ _ _ _ _ _ _ _ _ _ _ _ ----'
15