Table of Contents
Advertisement
l·t-!oll
ow sertw'
2NilIl ... .,.
5U~ort
,J'Pistol"l
~ring
4-PriminD
pump
5·Ch~k val~
6·f.e~
pump housing
7-
G5.I'l:1II
f,lte:r
8
-H
ollow
scrrw
-From'1Jellank
B·To
f
uel
f
iher
Fuel
feed pump
-
Cross
section
fuel
injection pwnp
l-Vaivr sprini
2-Delivery valve
J....Cylinder
4-P'h.Jftgltt
&-Comrol raC
k
E..contrOI
pinion
7.con,ro/.
sin""
8-Pll1l\gC'
spring
g·Tappet
lO-CamsJ"lilltt
Fuel iniecti on ptlmp
-CD
8
(I) Description
Th. pump body
Is an aluminum alloy .>sting and
oosos
all
the
moving
parts
of
pump
.Iements
and
the camshaft.
The governor hO\lsing
is attached
to
one
end
of
the
pump
body.
The camshaft is supported
by
two
tapered roUer
bearin
gs.
Like
the
engine
,"""shaft,
it
has
fou
r
cams,
one
for
each
pump
elernent
J
and
is driven
from
the
crankshaft
through a
train
of
gears
arranged for a
gear
ratio
of
2
to
!
.
For
each
two
rotations; of
crankshaft
,
the injection
pump
cam-
shaft
rotates
once.
The pump
element
consists
of
a
plunger,
barrel
(cy
linder)
,
tappet,
plunger
spring,
cont
rol
pillion
and sprlng-load
ed delivery
valve.
The
t
'ppet
rides
on
the
cam and
-pushes
the
plunger
up
wa
rd
ro
r
.ach
rotation
of
camshaft.
As
the
plunger
rises,
the
fuel in
the
barrel
becomes com pr
....
d
and
Is
forced
out
through the deuvcry
valvo
into
the
inje_
ction pipe
.
The upward
plunger
stroke,
effec-
tive
in comprcsslng Or
pressuriling
the
ruel,
is
variable, and
is
vaned by means
of the
conlroJ
rack
and
pinion
in the manner to be
explain~d
Jater.
1110
delivery
valve
,
through
which
a
shot of
fuel
is
forced out into
the
injection
pipe by
each
upward
motion
of tho
plunger,
is essentially
a
check yalve
having. special function
of
quickly reducing the
line
presswe the
moment the
plunger begins
co
descend
.
This
quick relief of
line pressure
is
necessary
to prevent
the
injection
noz.zle
from
dribbling at the
end of each
injeclion.
How
this
is
accomplished
will
become clear
.
Injoction
pump data
Cam
lift
8 mm
(0.3 I
5
in.)
Plunger diameter
6.5
mm
(0.256
in.)
Delivery valve
db.
6 mm (0236
in.);
retraction
volume
51
mm'
(0.003
cu
in.)istroke
Injection
order
1-3-4-
2
I
Injeclion
mtervaJ
90°
t
30'
(2)
Pumping
action
a.
Pump
element
constru
ction
The principal
parts
of the
pump el,ment are
Ihe
cylinder
(barrel)
and plUnger, as shDwn
in
this
perspective view. Both
are
machined to ex tremdy
close
tolerance,;
the plunger
slides
up ond down
in
the bore of
the
cylinder wi
til
such a small radial
clea"",ce "
to
make
the fit virtually
oil·tight.
25
Advertisement
Table of Contents
