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Патент USA US2410947

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Nov. 12, 1946.
l.. |-:. JOHNSON
2,410,947 ’
FUEL INJECTION PUMP MECHANISM
Filed April 19, 1943
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INVENTOR.
l.- /ayd E Johnson
BY @Á /í
ATTaRAœY,
Patented Nov. 12, 1946
2,410,947
UNITED STATES `PATENT oFFlcE
2,410,947
FUEL TNJECTToN PUMP MEcnANTsM
Lloyd E. Johnson, Fon du Lac Township, Tazewell
County, Ill., assignor to Caterpillar Tractor Co.,
San Leandro, Calif., a corporation of California f
Application April 19, 1943, Serial No. 483,633
4 Claims.
(Cl. 103-41)
1
j
2
My invention relates to fuel injection mecha
nlsm, and more particularly to such mecha
nism adapted for injection of relatively low vis
cosity fuel into an internal combustion engine.l
and actuating means therefor, and to lubricate
the bearing means for the pump plunger actuat
plunger during the injection stroke thereof. This
indicated by line 2-2 in Fig. l.
' ing means; and which is of relatively simple and
economical construction. Other objecis of my
In fuel injection systems for the injection of a 5 invention will become apparent from a perusal of
relatively low viscosity fuel, such as gasoline, into ' the following description thereof.
Referring to the drawing:
an internal combustion engine which is provided
Fig. 1 is a transverse vertical sectional view
with pumping mechanism for injecting the fuel
.of a form of fuel injection pump mechanism con
into each cylinder of the engine, in a. so-called
solid stream, there is the _problem of precluding 10 taining the construction of my invention.
Fig. 2 is a horizontal section taken in a plane
leakage of the fuel past the fuel injection pump
,
Fig. 3 is a horizontal section taken in planes
indicated by lines 3-3 in Fig. l.
as gasoline, is also usually quite volatile except
for a small portion of a gummy nature; and if it 15' Fig. 4 is a horizontal section taken in .planes
is so because a relatively low viscosity fuel, such
were to leak past the pump plunger, evaporation
would cause a gummy deposit that would impede
eflicacious operation of the plunger in the pump
cylinder within which the plunger is adapted to
indicated by lines I--4 in Fig. 1.
Fig. 5 is a horizontal section taken in a plane
indicated by line 5--5 in Fig. 1.
The lubricating and sealing means of my in
20 vention may be employed in association with any
type of fuel injection pump wherein an impeller
This problem does not exist so much with Diesel
located in a pump housing is operated by suitable
fuel oils of relatively high viscosity because the
actuating means. For purposes of explanation,
relatively high viscous nature of the oil tends to
it is shown in the form of fuel injection mech
preclude the leakage. Furthermore, relatively
high viscosity oils are usually of a relatively low 25 anism illustrated in Fig. l. Such injection mech
anism includes injection housing means compris
volatility', yand therefore do not tend to cause as
work.
~
-
much gumming as do relatively low viscosity'and '4
ing a tappet and camshaft casing 2 to which a
pump casing 3 is detachably connected by studs
4 and nuts 6.
has some lubricating properties which if a low 30 Adjacent the fuel discharge end thereof, pump
casing 3 is formed with an internal shoulder ‘I
rate of leakage should occur. will result in de
against which is clamped check valve cage 8 con
sirable lubrication between the working surfaces
taining spring thrust check valve 9; such clamp
of the cylinder and the plunger, which is not
ing being through a removably mounted plunger
true with more volatile fuels. such as gasoline,
which tends to dilute and destroy whatever lubri 35 barrel or cylinder II which is clamped in posi
tion by means of nut I2 screwed in the inside
cant is employed for the plunger action.
of casing 3 against shoulder I 3 formed on cylinder
In the past, provision has been made to pre
II; a suitable sealing ring Il being interposed
clude such leakage of relatively low viscosity fuels,
between nut I2 and shoulder I3. In this connec
by introduction of a relatively high viscosity
lubricant between the pump plunger and the cyl 40 tion, nut I2 is formed with inwardly extending
slots I6 to enable it to be engaged by a suitable
inder wall. However, in prior constructions with
tool for screwing and unscrewing of the nut when y
which I am familiar, the leakage precluding lubri
so desired. To hold cylinder II against angular
cant has been introduced through the Wall of the
or turning movement, a cap screw I1 screwed into
cylinder within which the pump plunger works.
Such arrangement is not desirable because of the 45 casing 3, is provided with an end extension I8
relatively highly volatile fuels, such as gasoline.
Also, a relatively high viscosity Diesel fuel oil
difficulties encountered in making a suitable con
engaging in a recess I9 formed adjacent the head
of cylinder I I.
With respect to multiple cylinder engines, a
plurality of individual injection pumps, one for
My invention is designed to overcome this prob 50 each cylinder of the engine, is employed; and the
lem by the provision of improved means facilitat
injection mechanism housing means contains all
of such pumps and the mechanism for actuating
ing the introduction of the sealing lubricant;
the saine.l A longitudinally extending fuel inlet
lwhich is of such character as to enable the sealing
nection between the cylinder and the housing
containing such cylinder, for the introduction of
the sealing lubricant.
passage or manifold 2| is formed in pump casing
lubricant to be employed for lubricating the loca
tion of engagement between the pump plunger 65 3, and receives a constant Supply of fuel at a rela
2,410,947
3
4
tively low pressure of about fifteen (15) to twenty `
(20) pounds per square inch, fed into it by a fuel
transfer pump (not shown) as is customary in
the art, and which continuously circulates the
fuel from a fuel tank (not shown). Communi
cating with fuel inlet passage 2| is a fuel inlet
orifice or port 22 formed in the wall of the head
of each pump cylinder Il; the cylinder wall hav
ing a short bleed passage 23 therethrough which
communicates with inlet port 22 and with the 10
inside of cylinder Il for a purpose to be subse
quently explained.
.
.
.
thrust against a shoulder 49 on the plunger, and
an end 5| of tappet sleeve 3|. When spring 45
thrusts retainer 41 against sleeve end 5| on
the return stroke of the plunger, the spacing
between the surface on shoulder 49 adapted to
engage retainer 41 and the flat surface 4| at the
tappet end of the plunger, is such as to provide
a slight clearance between wall 32 and retainer
41, thus enabling plunger 24 to be angularly
adjusted with ease.
The means for enabling angular adjustment
of the plunger while it is axially reciprocated ln
cludes a gear sector 52 which is split at 53, and
Slidably mounted in cylinder I| for axial recip
rigidly clamped to plunger end portion 42 by
rocation therein is a pump plunger 24 which is
preferably of the type wherein the quantity of 15 means of cap screw 54. The teeth on gear sec
tor 52 engage a rack 55 which is slidably mounted
fuel fed or injected past check valve 9 is con
in a recess in casing 2 between such casing and
trolled by angular adjustment or rotation of
pump casing 3; a recess 55 being formed in sleeve
the pump plunger about its axis. For this pur
3| to allow engagement between such gear teeth
pose, plunger 24 is formed adjacent its discharge
or injection end with annular groove 25 around 20 and the rack. Rack 55 is connected to suitable
governing means (not shown) operated from the
its periphery, which communicates with an axial
engine.
ly extending groove 21 adjacent a slanting or
To seal against leakage past the plunger of
scroll edge 28 adapted to work past port 22 as
relatively low viscosity fuel which the pump may
the plunger is reciprocated and angularly ad
justed. The fuel discharge end of the plunger 25 inject, I provide an interior passage 51 in the
pump plunger for conducting lubricant between
is flat, and at a right angle to the axis of the
the plunger and the cylinder wall, at a pressure
plunger.
above that at which the fuel is supplied by the
Thus, as the plunger is reciprocated by suit
transfer pump through inlet port 22 but con
able actuating means, and angularly adjusted
through suitable engine governing means, meter 30 siderably below the fuel injection pressure; such
lubricant pressure being preferably about twenty
ing of fuel injected by the pump is controlled
(20) to thirty (30) pounds per square inch. Be
in a well-known manner. When pump plunger
24 is actuated on its compression stroke to inject » cause of the higher pressure of the sealing lubri
cant, compared to that of the fuel supply pres
fuel when port 22 is closed as the plunger works
therepast, the pressure imparted to the fuelmay 35 sure, an emcacious seal is obtained. Further
more. the lubricant will also serve to lubrlcate the
be as high as two thousand (2,000) to four thou
working surfaces of the plunger and the cylinder.
sand (4,000) pounds per square inch. In Fig. 1,
the angular and the axial positions of plunger
In this connection, it will be noted that the tap
pet end portion 42 of the plunger extends beyond
24 are shown substantially at the termination of
injection, as slanting edge 28 is just about to 40 the tappet end of cylinder || throughout the
entire stroke of the plunger. Such arrangement
uncover inlet port 22.
Actuating means in the form of tappet mecha
enables interior passage 51 to lead to the flat
end surface 4| of the plunger for supplying of
nism 29 is provided in casing 2 for imparting
the injection or discharge stroke to plunger 24.
lubricant thereto at that location, which makes
Each of the tappet mechanisms in casing 2 com 45 for a simple construction. Intermediate the
plunger ends, passage 51 terminates in radially
prises a sleeve 3| having an intermediate par
extending orifices 58 communicating with a
tition wall 32 secured therein by any suitable
peripheral groove 59 formed in the plunger. Thus
means, such as welding, and which is slidably
mounted for axial reciprocatlon in a bearing
a sealing ring of fluid will be maintained in
wall surface 33 formed in casing 2. A cam 50 groove 59 as sealing fluid is supplied through
follower roller 34 is located at one side of wall
32 and is journalled for rotation about a pin
passage 51.
For supplying fluid to passage 51, I_ provide a.
36, on suitable roller bearings 31; the roller 34
passage 5| in tappet partition wall 32, which is
engaging cam 38 on longitudinally extending
open to a side of tappet sleeve 3| adjacent one
camshaft 39 which is adapted to be driven from 55 end, and which includes an orifice 62 at its op
the engine.
~
posite end in communication with passage 51.
The opposite side of wall 32 is formed with a
As fluid flows from tappet passage 5| into
ñat surface adapted to be freely engaged by a
plunger passage 51, the location of engagement
between the plunger and its actuating means
flat end surface 4| formed on the tappet end por
tion 42 of plunger >24. Thus, as the plunger is 60 will be well lubricated, which facilitates angular
adjustment of the plunger when tappet wall 32
moved axially by the tappet mechanism, it may
engages plunger end surface 4I during the in
be readily turned angularly for the purpose previ
ously explained. It will be noted from Fig. 4,
jection stroke of the pump.
Means is provided for continuously pumping
that the tappet mechanisms 29 are provided with
fiats 43 on their sides; and a pin 44 is positioned 65 lubricant through passages 5| and 51, and at
the same time lubricating bearing 33 in which
between the flats of adjacent tappet mechanisms
the tappet mechanism slides. Casing 2 is
29, so as to hold such mechanisms against rota
tion or turning as they are reciprocated.
adapted to contain a supply of lubricant which
is continuously fed by means of a pump 53 in
For effecting the return or suction stroke of
plunger 24 after the discharge stroke, a spring 70 cluding meshing gears 54, one of which is driven
45 is interposed between nut I2 and a spring
from camshaft 39. The pump gears draw lubri
retainer 41 at the tappet end portion 42 of the
cant into the pump through inlet passage 55, and
plunger. Spring retainer 41 is provided with an
discharge lubricant through passage 51 which
inwardly extending slot 48 to enable it to be
communicates with a lubricant feed manifold or
slipped over plunger 24, and is adapted to be 75 passage 68 in the inside wall of casing 2 adja
2,410,947,
5
cent tappet sleeves 3|. A suitable pressure re
lief valve -69 communicates with passage 61.
Feed passage 68 is open to sleeve 3| and the
portion of sleeve 3| adjacent feed passage 68 is
formed with a recess 1| which communicates
with passage 6|. Such arrangement allows free
flow of lubricant into passage 6|; and at the
same time, the lubricant will lubricate bearing 33.
said cylinder and bearing wall, said passages
registering at the engageable surfaces of the
plunger and tappet to permit the passage of
lubricant and to effect lubrication of said
surfaces.
2. Fuel injection mechanism comprising a
pump which includes a plunger reciprocably
mounted in a cylinder for transferring fuel in
metered quantities from a source of supply to
During injection of fuel at the previously
mentioned high pressure, leakage might occur 10 an engine, said plunger having a circumscri‘bing
recess spaced from its head and communicable
past the plunger irrespective of the sealing fluid
with said source of supply for return thereto of
in groove 59, but this is prevented by the pre
fuel leaking past-the head of the plunger, a sec
viously mentioned bleed passage 23. The inner
` ond circumscribing recess spaced farther from
end of passage 23 is in such position that during
the time fuel is actually injected by the pump 15 the head of the plunger, and means for supply
ing lubricant under pressure to said second
plunger, it communicates with a peripheral
recess.
groove '|2 in the plunger, which is located be
3. Fuel injection mechanism comprising a
tween the injection end of the plunger and seal
pump which includes a plunger reciprocably
ing ñuid groove 59. As a result, high pressure
injection fuel can only leak past the plunger 20 mounted in a cylinder for transferring fuel in
pressure off to the low pressure which obtains
metered quantities from a source of supply to an
engine, said plunger having a circumscribing re
if so desired, in Diesel or compression ignition
pressure of the source of fuel supply, to said sec
as far as groove 12, as passage 23 will bleed the
cess spaced from its head and communicable
in fuel inlet manifold 2|.
with said source of supply for return thereto of
Although the construction of my invention is
particularly adapted for employment in fuel in 25 fuel leaking past the head of the plunger, a
second circumscribing recess spaced farther
jection pumps adapted for the injection of a rela
from the head of the plunger, and means for sup
tively low viscosity fuel, such as gasoline, to be
plying lubricant under pressure, exceeding the
supplied to spark ignition engines, it may be used,
,
fuel injection pumps where relatively low vis 30 ond recess.
4. Fuel injection mechanism comprising a
cosity fuel oil is employed, and leakage thereof
pump which includes a plunger reciprocably
past the pump plunger might prove detrimental.
mounted in a cylinder for transferring fuel from
I claim:
a source of supply to an engine, means for re
1. Fuel injection mechanism comprising a.
pump cylinder, a. pump plunger reciprocably 35 lieving pressure on fuel leaking past the head of
the plunger, and means for supplying lubricant
mounted therein, a reciprocable tappet member
to the cylinder walls at a pressure exceeding that
engageable with an end of the plunger. a bearing
of the leakage fuel.
wall for guiding said tappet member, and lubri
LLOYD E. JOHNSON.
cating means comprising passages through the
plunger and tappet for supplying lubricant to 40
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