DIESEL
ENGINE
05
SERIES
WSM,
01640
(1)
Pump
Element
I
1
1790F10260
(2)
Delivery
Valve
a
2
11790F10270
The
pump
element
(1)
is
consist
of
the plunger
(3)
and cylinder
(2).
The
sliding
surfaces are super-precision machined to
maintain injection pressure at engine
low
speeds. Since
the
driving
face
(7)
fits
in
the
control
sleeve, the plunger
(3)
is rotated
by
the movement
of
the control rack to
increase
or
decrease
of
fuel delivery.
As described above, the plunger
(3)
is
machined to
have the
slot
(5)
and the control groove
(6).
(1)
Pump
Element
(5)
Slot
(2)
Cylinder
(6)
Control
Groove
(3)
Plunger
(7)
Driving
Face
(4)
Feed
Hole
1
1790M10231
The delivery valve consists
of
the delivery valve
(1)
and delivery valve seat
(2).
The delivery valve performs the
following
functions.
1.
Reverse
flow
preventing function
If
the fuel
flow
reverse
from
the injection nozzle side
when the plunger lowers, the time lag between
the
next
delivery start and the nozzle injection start increases.
To
avoid this, the delivery chamber to injection pipe
interruption
by
delivery valve
(1)
prevents
this
reverse
flow,
thus keeping fuel always filled
in
the
nozzle
and
pipe.
2.
Suck-back function
After completing the fuel delivery, the delivery valve
lowers, and the relief plunger
(4)
end contacts the
delivery valve seat
(2).
The valve further lowers
until
its
seat surface
(3)
seats
firmly
the delivery valve seat.
During
this
time, the amount
of
fuel corresponding
to
(A)
is
sucked back
from
inside the injection pipe, the
pressure inside the pipe
is
reduced, thus leading
to
an
improved injection
shut
off
and preventing after leakage
dribbling.
(1)
Delivery
Valve
(2)
Delivery
Valve
Seat
(3)
Seat
Surface
(4)
Relief
Plunger
11
790M1024
1
M-27
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