Daedong DSC48, Workshop Manual

Page: 89 / 290

Apr. 2007
2
-13
DSC48
417W225A
2.4 FUEL SYSTEM
(1) Fuel tank (5) Injection nozzle
(2) Fuel fi lter (6) Fuel over fl ow pipe
(3) Injection pump (7) Fuel pump
(4) Injection pipe
2.4.1 FLOW OF FUEL
The fuel pump (7) sucks up fuel from the fuel tank (1) and
pushes the fuel to the fuel
fi lter (2) which removes dust,
water, etc. from the fuel. Then, the fuel is supplied to the
injection pump (3). The injection pump compresses the fuel
and pushes the compressed fuel through the injection pipe
to the injection nozzles. The nozzles spray the fuel into
each cylinder. The excessive fuel from the injection pump
to the injection nozzles is collected in the fuel overflow
pipes and returns to the fuel tank.
417W226A
(1) Inlet valve (6) Diaphragm
(2) Push rod (7) Fuel camshaft
(3) Tappet (a) From fuel fi lter
(4) Outlet valve (b) To injection pump
(5) Chamber
2.4.2 FUEL FEED PUMP
The fuel feed pump sends the fi ltered fuel to the injection
pump.The diaphragm (6) is linked to the tappet (3) with the
push rod (2). The tappet is reciprocated by the eccentric
cam on the fuel camshaft (7).
(A) Intake stroke
When the diaphragm is pulled down by the spring, vacuum
in the chamber (5) causes the outlet valve (4) to close and
the atmospheric pressure in the fuel tank forces the fuel
into the chamber, opening the inlet valve (1).
(B) Discharge stroke
When the diaphragm is pushed up by the cam, the pres-
sure in the chamber causes the inlet valve to close and
forces out the fuel, opening the outlet valve.