FAW Jiefang Automotive 485, Operation & Maintenance Manual

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1-Diesel oil filter 2-Speed regulator 3-Fuel-transfer pump 4-Fuel-injection pump
5-High-pressure fuel pipe 6-Fuel injector 7-Fuel return pipe 8-Advancer
Fig. 11 Fuel & speed-regulating system
2. Diesel oil filter
Diesel oil filter is used to remove the impurities in diesel oil. It consists of casing, filter seat
and filter element etc.
3. Fuel-injection pump
Fuel-injection pump is No.1 series pump or BQ pump type, with right-integration plunger
design. This pump consists of pump body, camshaft, plunger couple, oil-out valve couple and
control mechanism etc.
The fuel-injection pump is driven by its timing gear. Through transmission effect of
fuel-injection pump's camshaft, roller and tappet, the piston of the pump is moved back and forth.
The control mechanism for changing fuel-supply flow-rate consists of speed-governing
pull-rod, shifting fork, and adjusting-arm fitted onto plunger of fuel-injection pump. The position
of pull-rod is controlled by speed-governor. Moving the pull-rod forward will increase fuel-supply
flow-rate, and moving back will decrease it.
Do not arbitrarily disassemble/assemble the fuel-injection pump which has been calibrated by
its manufacturer.
When disassembling/assembling, repairing or adjusting is really need, it is necessary to keep
clean. Plunger couples and oil-out valve couples etc are not allowed to be interchanged.
4. Speed governor
Speed governor is of whole-course mechanical centrifugal type. It consists of driving parts,
sliding disc, sliding bush, speed-governing spring, speed-governing handling shaft etc. See Fig.12.
(Speed sensitive element for Model T7B is steel ball, and for Model T110 is fly-ball).
Operating the speed handle can change the speed of the engine. Changing the position of
speed-governing handle means changing the acting force of spring, and the balancing position of
speed-governing pull-rod will accordingly be changed. When the speed-governing handle is
moved towards the direction on which the speed-governing spring is twisted tight, fuel-supply
flow-rate will increase and engine speed will increase accordingly . When the handle is moved
towards the direction on which the spring is twisted loose, fuel-supply flow-rate will decrease and
engine speed will decrease accordingly. Therefore, to restrict maximum idle-speed and minimum
steady speed, it is only necessary to restrict the limit positions on the handle, which can be
realized by using the two screws on the speed governor. This adjustment work has already been
done before delivery, and should not be arbitrarily performed during operation.
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