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Патент USA US2131228

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Sept. `27, 1938.
Original Filed Sept. 14, 1935
Patented Sept. 27, 1938 ,
Rudolf Lïûrange, Stuttgart-Feuerbach,
Original application September 14, 1935, Serial
No. 40,598. Diirided and this application Au;
gust 11, 1936, Serial No. 95,3991.. In Germany
September 20,. 1934
1 Claim.v (CL 10S-41)
This is a division from application Serial Num
relieving groove. 6' cam by
ber 40,598 of September 14,1935.
This invention relates to a fuel injection pump
particularly for use with compression ignition and
like engines and of the kind wherein a plunger
with constant stroke operates within a barrel
relative to which it is angularly displaced for reg
ulating the effective stroke of the plunger, the
regulation being obtained by the provisionv of hel
ical edges which co-operate for relieving thev pump
pressure at any suitable point of the delivery
stroke according to the angular position of the
The object of the invention is to obtain a pump
15 construction wherein the inlet stream of fuel can
be readily separated from the relieving stream
thereof without the employment of a hollow
plunger, and the invention consists in this respect
in the provision of a solid plunger> having a heli
cal relieving groove which is in constant com
munication, through a surrounding barrel, with a
relief outlet in the pump casing, the inlet of said
with the pump chamber through the recess’ 5 at
different points of the delivery stroke of. the
plunger for relieving the pressure in the chamber 5
through the groove and through the relief. outlet.
The volume of fuel delivered’ bythe pump- is reg
ulatedin this manner'. As the plunger uncovers
the inlet port, fuel is admitted into the pump
chamber, and after the portl hasy been closed. by 10
the plunger during the delivery stroke.- ofthe
latter, fuel. will be forced’. past a delivery valve D
and through a delivery- port J into thev engine
cylinder until the relieving passages are opened..
As the relieving groove 6 enters into communica- 15
tion with the pump chamber, it traverses an edge
2 of the recess'` 5 which is substantially parallel to
the edge of the groove.
later according to the angular position of the
In the modified. pump construction. shown in
Fig. 2, an additional duct. K is' providedv through 20
which the pump chamber communicates with the
relief outlet Y. This duct opens into the pump
chamber through a port which is substantially' on
a level with the. inlet port and which is opened.
and closed simultaneously with the latter. It 25
will therefore be> seen that while the. ports are
opened, the pump chamber will be flushed with
plunger, into communication with a recess in the
pump chamber for relieving the pump pressure
fuel' passing directly from. the inlet and through
the chamber' into the relief outlet. This ilow of
through the relief outlet.
Fig. 1 of the accompanying drawing represents
liquid, which clears the. pump chamber of all air 30
bubbles, continues for about one-half or two
casing being in communication with the pump
chamber through a port controlled by the plunger,
25 and the relieving groove of the latter being
adapted, in known manner, to enter, sooner or
angularV displacement of the plunger M,be put intocommunicatiorr
a vertical section of a pump constructed accord
ing to the invention, and
Fig. 2 is a vertical section of a modified form of
35 the pump.
'I‘he pump comprises a casing B wherein a
barrel L is rigidlyfitted as a guide fora solid pump
plunger M. The casing B is provided with a fuel
inlet A and with a relief outlet Y, and it has two
40 internal, circumferential grooves I and I0 each
forming, together with the barrel L, a passage for
the fuel. 'I'he groove I communicates with the
fuel inlet A and it also communicates, through a
conduit I2 in the barrel L with a port situated in
45 the pump chamber 4. This port is traversed by
the upper end of the plunger M and is thus con
trolled by the latter. The groove I 0 communi
cates, through a duct I3, with the relief outlet Y,
and it also communicates, through ducts 9, with
V50 an internal, circumferential groove 8- in the bar
thirds of the time occupied by the complete
‘plunger stroke, according to- the construction of
the operating cam.
The fuel is supplied in any suitable manner, for 35.
instance by means of a separate feed pump, and',
it will be seen that in both. pump constructions a
continuous passage is formed through which fuel,
which is not forced through the delivery pipe, can
circulate from. and to a supply tank which. is in 40
communication with they inlet A as well as with
the relief outlet Y'.
The delivery stroke of the plunger M is pro
duced through the: medium of a camv I4 and an
oscillating -lever I5 which bearsl by means of a 45 f
-cup-shaped thrust member S against the head I6
of the plunger. The return stroke ofthe plungerv
is effected by a spring C which engages the
plunger head inside the thrust member S.
The angular displacement of the plunger for 5o
rel L. The latter groove cooperates with the
regulating the effective stroke of the pump, is
plunger M to form a passage which is in constant
communication with a helical relieving groove 6
made in the plunger M. There is a recess 5 made
'effected through the medium of a rod D1 which is
in the wall forming the pump chamber l, and the
arranged at right anglesv to the plunger and slid
ably mounted in rigid bearings I'l for rectilinear
movement. Each pump plunger of the engine is 55
ñtted with an operating lever R which is suitably
coupled to the rod D1, so that the rectilinear
movement oi’ the rod will be transmitted to the
plungers and converted in the latter to a rotary
The casting. B which encloses the barrel L is
detachably connected to a casing F which encloses
the relieving groove in constant communication
with the barrel groove while moving the free end
of the plunger across said port, a delivery valve
closing the end of the bß rrel and forming a pump
chamber between it and the free end of the 5
plunger, the barrel having in said pump chamber
a recess adapted, during the delivery stroke of the
the operating elements.
plunger, to be thrown into communication with
I claim:
the relieving groove of the latter for relieving the
A fuel injection pump of the character de
pump pressure through the relief outlet, and
scribed comprising a casing having a fuel inlet means for imparting to the plunger an angular 10
and a relief outlet, a barrel' mounted in said displacement in order to determine the point of
casing provided on the one hand with a port` the stroke at which the relief takes place, the
which communicates with said fuel inlet and on
15 the other hand with an internal circumferential
groove which communicates with said relief out
let, a solid- pump plunger fitted snugly in said
barrel and adapted to control said port, said
plunger being formed with a helical relieving
20 groove, means for reciprocating the plunger with
in the barrel, said means operative to maintain
barrel being provided with a duct which is closed
by the plunger substantially at the same time as 15
the inlet port and which communicates with the
relief outlet for allowing free circulation of fuel `
through >the pump chamber when the inlet port is
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