l·t-!o
ll
ow
sertw'
2NilIl
... .,.
5U~or
t
,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
fiher
Fuel feed pump - Cross section
fuel injection
pwnp
l-Vaivr sprini
2-Delivery
va
l
ve
J....Cylinder
4-P'h.Jftgltt
&-Comrol r
aC
k
E..contrO
I pinion
7.con,ro/. sin""
8-Pl
l1
l\gC'
spring
g·Tappet
lO-CamsJ"lilltt
Fuel iniection ptlmp
-
CD
8
(I)
Description
Th.
pump
body
Is
an aluminum alloy .>sting
and
ooso
s 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.
Lik
e the engine ,"""shaft, it has
fo
ur
cams,
one
fo
r
each
pump elernent
J
and
is
driven
from the crankshaft
through
a t
ra
in
of g
ears
arranged
f
or
a g
ea
r ratio
of
2 to !.
For
ea
ch
two
rotations;
of cr
ankshaft
, the
inje
c
tion
pum
p c
am
-
shaft
ro
tates once.
The
pump
el
emen
t co
ns
ists
of a
plu
nge
r,
ba
rrel
(cylinder), tappet, plunger spring, control pi
lli
on
and sprlng-
lo
ad
ed delivery
va
lv
e. T
he
t
'ppet
rid
es
on the c
am
a
nd
-pu
sh
es the
plu
ng
er
up
wa
rd
ro
r
.ach
rotation
of
camshaft.
As
the
plunger
rise
s,
the fuel
in
the barrel becomes compr
....
d
and
Is
forced out through the deuvcry
valvo
into the
inje
_ction p
ip
e.
The
upward
plunge
r stroke, effec-
ti
ve
in
c
omp
r
csslng
Or
press
ur
iling
the
ruel
, is
variable,
and is vaned by means
of
the
co
nlroJ
rack
and
pinion
in
the
manner
to
be
expl
ai
n~d
Jate
r.
1110
delivery
valve
, through
whi
ch
a shot
of
fue
l
is
forced
out
into the in
je
ction pipe by each upward
motion
of
tho
plunge
r,
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
in
jection
noz.zl
e f
rom
dribbling at the
end
of
each injeclion. How this
is
accomplished
will
become clear.
In
joction
pump
data
Cam
lift
8
mm
(0.3 I 5 in.)
Pl
unger
diameter
6.5 mm (0.256 i
n.)
Delivery valve db.
6
mm
(0236
in.); retraction
volume
51 mm'
(0.003 cu in.)istroke
In
jection order
1-3-4-
2
I
Injecl
ion
mterv
aJ
90° t
30'
(2) Pumping action
a.
Pum
p
el
eme
nt con
st
ru
ction
The principal parts
of
the
pump
el,ment
are
Ih
e
cylinder (barrel) and plUnger,
as
shDwn
in
this
perspective
view.
Bo
th are machined to ex
tr
emdy
close
tolerance,; the plunger slides
up
ond
dow
n
in the bore
of
the cylinder
wi
til such a small radial
clea"",
ce
" to make the fit virtually o
il
·
tigh
t.
25
To Next Page
Loading...
