Doosan D20G, Service Manual

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4TNV98 & 4TNE98 Diesel Engine Section 1. General Service Information 10
Function of Major Engine Components
Components Functions
Air Cleaner
The air cleaner prevents airborne contaminants from entering the
engine. Since the air cleaner is application specific, it must be carefully
selected by an application engineer. It is not part of the basic engine
package as shipped from the Yanmar factory. Periodic replacement of
the air cleaner filter element is necessary. See the Periodic Maintenance
Schedule on page 39 for the replacement frequency.
Dipstick (Engine Oil)
The alternator is driven by a V-belt which is powered by the crankshaft
V-pulley. The alternator supplies electricity to the engine systems and
charges the battery while the engine is running.
Dipstick (Engine Oil)
The engine oil dipstick is used to determine the amount of engine oil in
the crankcase.
Electric Fuel Pump
(If Equipped)
The electric fuel pump makes sure there is a constant supply of diesel
fuel to the fuel injection pump. The electric fuel pump is electro-magnetic
and runs on 12 VDC. An electic fuel pump may be installed as an option
or as standard equipment. Standard equipment may vary based on
engine model and specification. If an electic fuel pump is installed, turn
the key switch to the ON position for 10 to 15 seconds to prime the fuel
system.
Engine Oil Filter
The engine oil filter removes contaminants and sediments from the
engine oil. Periodic replacement of the engine oil filter is necessary. See
the Periodic Maintenance Schedule on page 39 for the replacement
frequency.
Engine Oil Cooler
(If Equipped)
The engine oil cooler helps to keep the engine oil cool. Engine coolant
from the cooling system is circulated through an adapter at the base of
the engine oil filter assembly and then returned to the coolant pump
inlet.
Fuel Filter
The fuel filter removes contaminants and sediments from the diesel fuel.
Periodic replacement of the fuel filter is necessary. See the Periodic
Maintenance Schedule on page 39 for the replacement frequency.
Please note that the word “diesel” is implied throughout this
manual when the word “fuel” is used.
Fuel Filter/ Water Separator
The fuel filter / water separator removes contaminants, sediments and
water from the diesel fuel going to the fuel filter. This is a required
component of the fuel system. This is standard equipment with every
engine. The separator is installed between the fuel tank and the electric
fuel pump. Periodically drain the water from the fuel filter / water
separator.
Fuel Priming Lever
(If Equipped)
If the unit has a mechanical fuel pump, a fuel priming lever on the
mechanical fuel pump primes the fuel system. The fuel sytem needs to
be primed before you start the engine for the first time, if you run out of
fuel, or if fuel system service is performed. To prime the fuel system,
operate the fuel priming lever until the cup in the fuel filter is full of fuel.
Fuel Tank
The fuel tank is a reservoir that holds diesel fuel. When the fuel leaves
the fuel tank it goes to the fuel filter / water separator. Next the fuel is
pumped to the fuel filter by the electric fuel pump. Then the fuel goes to
the fuel injection pump. Since the fuel is used to keep the fuel injection
pump cool and lubricated, more fuel than necessary enters the injection
pump. When the injection pump pressure reaches a preset value, a relief
valve allows the excess fuel to be returned back to the fuel tank. The fuel
tank is a required engine component.
Side and Top Filler Port
(Engine Oil)
You can fill the crankcase with engine oil from either the side or the top
filler port depending upon which one is most convenient.
Starter Motor
The starter motor is powered by the battery. When you turn the key
switch in the operator’s console to the START position, the starter motor
engages with the ring gear installed on the flywheel and starts the
flywheel in motion.