D439E Service Manual 2. Engine Mechanical System (D439E)
16
2. Engine Mechanical
System (D439E)
General
Description
Combustion
1. Combustion chamber consists of cylinder head,
piston Injector installed to the cylinder head and
valve.
2. Fuel is supplied to supply pump through the fuel
filter installed to the frame. Fuel is also supplied to
injectors throuqh injection pipe No. 1,2,3 and 4 in
common rail assembly.
3. Combustion is accomplished when fuel is Injected
directly Into combustion chamber, at that time
explosion pressure applies to the piston directly.
4. For better I efficient cooling of combustion
chamber, water director is press-fit under cylinder
head floor, which induces the coolant flow.
Valve Mechanism
1. Heat resistant steel with surface treatment is used
for intake and exhaust valve. The valve seat angle
is 45.
2. Valve stem seal, Installed to the stem, adjusts the
lubricant amount on the sliding surface of valve
and valve guide.
NOTE : Valve guide with carbon cutter is used for
exhaust valve.
3. Valve spring consists of two valve springs having
Irregular pitches. The coil directions of inner and
outer springs are opposite each other.
4. Rocker shaft is hollow cylindrical rod, whose each
end are sealed with sealing cap. Inner space of
the shaft is an engine oil passage.
5. Steel ball is installed to the lower end of push rod
and rocker assembly is installed to upper end.
6. Tappet has a cylindrical shape. As enlarging the
contacting surface contacted with camshaft, it
helps to prevent partial wear and to increase Its
durability.
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