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Патент USA US2135539

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Patented Nov. 8, 1938
2,135,539
UNITED STATES
PATENT OFFICE
2,135,539
CARBURETOR.
John B. Sinderson, Rockford, Ill.
Application April 27, 1936, Serial No. 76,569
15 Claims.
This invention relates to carburetors, and has
, for its principal object the provision of a car-
buretor which does not rely upon the impinge
ment of inrushing air upon a spray nozzle to
produce the mixture, but which has an air meter
ing valve mechanically connected with a fuel
meteringjvalve so that any movement of the
one results in a proportionate movement of the
other, thereby de?nitely insuring a mixture of
predetermined proportions at every point
throughout the range of operation.
An important feature of my improved carbu
retor is the provision of a bellows responsive to
reductionin pressure in the carburetor casing to
move a perforated air metering valve ring relative
to a conical head, whereby to vary the section of
the throat between ‘the ring and head and ac
cordingly vary the amount of air admitted for
the combustible mixture.
20 Another important feature is the provision of
a ‘novel form of fuel metering valve comprising
‘a slotted plunger which in its endwise movement
uncovers more and more of the slot therein and
accordingly varies the amount of fuel supplied.
This plunger by virtue of another novel feature
has ‘a double seal against fuel leakage in its closed
position.
The invention is illustrated in the accompany
ing drawing, in which—
30
'
Figure -1 is a central longitudinal section
through a carburetor embodying my invention;
‘Fig. 12 is anenlarged sectional detail of the fuel
valve portion of Fig. 1;
Fig.3 is a cross-section on line 3-3 of Fig. 2;
35
Fig. 4 is a fragmentarysectional view illustrat
ing a modi?ed or alternative construction;
Fig. 5 is a side view of an air metering head
o‘f'rmodi?ed form, and
Figs. 6 and 7 are fragmentary views showing
different forms of fuel metering slots for'the fuel
valve.
The same reference numerals are applied to
corresponding parts throughout the views. '
<As indicated above, the carburetor of my in
45 vention does not ‘rely for its mixture upon the
impingement of air upon a spray nozzle.
It is
well known in .this art that the cross-section of
the .air' inlet and ‘the bore of the spray nozzle
can be proportioned to give a mixture of exactly
50 right proportionsat any one suction in the throat
of the carburetor, but atall other suctions the
proportions of the mixture will be wrong. The
carburetor herein disclosed is so constructed that
for every degree of opening of the air valve, the
55 fuel valve issimultaneously opened to the cor
(Cl. 261-50)
rect position to insure a mixture of predeter
mined proportions at every point throughout the
range of operation. While I at present prefer
that the mixture be constant through the full
range, it will soon appear from the description
of my construction that I can readily arrange
to provide for a leaner mixture with increasing
manifold pressure, and thus obtain maximum
economy.
Referring ?rst particularly to Fig. 1, 5 is the
usual butter?y throttle valve in the outlet pas
sage 6, the extent of opening of which determines
the amount of fuel mixture passing to the en
gine. Fuel is discharged at 1 onto the cone 8
which may be either a hollow metal member with 15
numerous small holes provided therein, or else,
as herein shown, a cone of ?ne screen or foram
inous material, so that the air can flow through
the apertures or interstices and form a combus
tible mixture with the fuel discharged onto the 20
cone. At 9 is a frusto-conical head having a cy
lindrical portion Ii] on which a valve ring H
has a close working ?t. i2 is a collapsible and
expansible bellows supported on the plate l3
clamped to the casing M of the carburetor by
the small housing I5 fastened suitably by screws
l6 to the casing. The housing l5 encloses the
bellows l2 and has air inlet openings [1 in the
end wall thereof shown covered by the ring I l,
the latter being in closed position. The end wall
of housing I5 also provides a support for the
head 9 which is threaded in place, as indicated
at i8. A yoke l9 spans the head 9 and is at
tached to the ring ll so as to transmit move
ment to the rod 20 when the ring H rises and
falls with the collapsing and expanding of the
bellows.‘ When a reduction in pressure is created
in the casing M by the turning over of the en
gine, the intake manifold of which communi
cates with the outlet passage 6, as indicated at
2|, air rushes in between the conical surface of
the head 9 and the inner circumference of the
ring II, when the latter has raised past the cy
lindrical portion l0. Obviously, the higher the
ring H is raised the greater the volume of air
admitted. At wide open throttle, enough air will
be admitted through the ring H to make a prop
erly proportioned mixture with the fuel dis
charged at 1 onto the cone 8. The ring H, in
other words, is an apertured piston member
movable up and down in the casing substantially
without air leakage around it, and is movable
under atmospheric pressure in response to reduc
tion in pressure in the casing.
The fuel discharge port 1 is in the bottom 55
2
2,135,539
of a housing 22 supported on and projecting into
the carburetor casing Hi and secured with its
cover 23 to the casing suitably by screws 24.
The housing 22 provides a ?oat chamber 25 there
in communicating through a tube 26 with a
source of fuel supply which may be either a
vacuum tank delivering fuel by gravity to the
?oat chamber, in the usual way, or a fuel pump
driven by the engine. The ?oat 21 operates the
10 valve 28 to shut off communication between the
tube 25 and the ?oat chamber when fuel is ap
proximately at the level indicated, above the
intake end of the fuel passage 29 leading to an
outlet 3!}. Fuel is delivered from the outlet 33
to the discharge port 1 in regulated amounts,
as hereinafter appears, depending upon the posi
tion of the fuel metering valve 3| which is oper
ated by a rod 32. Now, the rods 2|] and 32 have
racks 33 and 34, respectively, meshing with a
gear 35 mounted for rotation on a shaft 36 suit
ably supported in the casing l4. A yoke 31 fas:
tened to the inside of the casing M, as shown,
provides guides in two planes at right angles to
one another for the racks 33 and 34’ to maintain
' these racks in proper meshing engagement with
30.
that the fuel valve can be given the same lineal
movement as the air valve H, as shown in Fig. 1.
or else the reduction gearing shown at 35’ in
Fig. 4 may be employed wherein the rack 33 oper
ates on the portion of large diameter of the gear
element 35’ and the rack
portion of small diameter.
operates
.
on
the
On the other hand, if the mixture is to become
leaner with increasing manifold pressure, I may
do either one of two things to accomplish this 10
result: I may either varyv the inlet‘of air so as '
to feed more air 'in proportion to‘fuel with in
creased manifold pressure, or I may vary the
feeding of fuel so as to deliver less fuel with in
creased manifold pressure. The differential air 15
feed is'obtainable by simply providing a head 9',
as shown in Fig. 5, in place of the conical head
9 shown in Fig. 1. The convex'form of the sur
face of the head 9','especially in the region of
the cylindrical base portion [3, will obviously 20
cut down the amount of‘ air delivered in'rela
tion to the amount of fuel under low manifold
pressure conditions, although under increased .
manifold pressure conditions, enoughadditional
air will be supplied in relation'to the fuel delivery,
2.5“
to provide aleaner mixture. ‘Obviously, since the "
the gears 35. This yoke also provides an abut
ment for a light coiled compression spring 38 air control head can be .unthreaded at l3, it is.
a simple matter to substitute a head of the de
which surrounds a portion of the rod 20 and en
sired
shape to obtainwhatever operating char
gages the yokes l9 and 31 at opposite ends. This
spring serves to return the interconnected parts ' acteristicsare desired. In Fig. 7 Ihave shown 3.9
to the position illustrated, namely, with the air a fuel metering slot 39’ in a valve 3|’, which,
metering valve ring H and fuel metering valve because of its narrowing down toward the right
hand end, will provide for less fuel deliveryrin re
3| in closed position.
The operation of the carburetor, as thus far lation to air with increased manifold pressure
described, is as follows: When the throttle valve and accordingly result in a leaner mixture. It
5 is opened and the engine is turned over in is obviously a very simple matter to substitute
one valve for another in the present construe-H 7
the usual way for starting, a reduction in pres
sure is created in the casing M of the carburetor. tion, inasmuch as the valve 3| has, a sliding ?t. 1
Atmospheric pressure acting upon the ring ||
therefore starts the collapse of the bellows l2,
and the ring rises off the cylindrical portion | i] of
the head 9 and admits air through the annular
space between the ring and the conical portion
of the head. Now, of course, the ring will sta
bilize itself at a certain level where the volume
' of air taken in balances or satis?es the suction
in the intake manifold of the engine. In view
of the fact that the movement of the ring |l
results in proportional movement of the fuel
metering valve 3|, the latter, as will soon appear,
' delivers a proportionate amount of, fuel through
the port 1 onto the cone 8 for mixture with. the
air passing through the cone, whereby to furnish
a correctly proportioned mixture to the engine.
The proportioning of fuel and air, as will soon,
' appear, may be either constant throughout the
range of operation or varied so as to become
leaner with increasing manifold pressure, as dis—'
tinguished from the simple spraying type of
60 carburetor which enriches the mixture with in
' creasing manifold pressure and consequent in~
the casing and thereby operate the valve 3| ‘pro
portionately. In other words, there is assurance
of the desired amount of power and the desired
lengthrof movement of the ring H required in
metering the air and fuel.
Referring
closed in a
press ?t in
housing 22.
'
7
to Figs. 2 and 3, the valve 3| isen 50.
bushing 40 suitably entered with a
the bore 4| in ‘the bottom of the
A hole 42 in one end of the'bushing
establishes communication between the passage
29 in the housing22 and the L-shaped outlet pas
5.5.
sage 30 in a plug 43 entered with a press ?t'in
the end of the bushing 40. A ?at is milled length
wise of the bottom of the bushing 40’ to provide
a fuel outlet passage “communicating at one
end with the fuel discharge port, ‘I, as shown, and 60.
communicating near'its other end with a port 45
‘and at its other end with another port 46 pro
vided in the wall of the bushing. Now, a sleeve
the mixture becomes somewhat leaner as the 41 entered with a press'?t in the bushing .43‘
provides a bearing wherein'the valve 3| is ar 65.
manifold pressure increases. With the carbu
retor of my invention, it is a simple matter tov ranged to operate withv a close working ?t. The
obtain whatever characteristics are desired, as latter comprises a cylindrical body 48 forming a
continuation of the rod 32, which is milled off
will now be pointed out.
'
A constant proportion is obtained if the head lengthwise from its inner end, as at 49, to the
9 is conical or frusto-conical, and the slope of point 55 to provide a fuel passage 5|. Two sleeves;
its sides is calculated correctly in relation to the 52 and 53 are secured onto the body 48 either
width of the fuel metering slot 39 of the valve , with'apress ?t or by sweat-soldering, and be
3|, and the valve 3] is opened inthe correct, tween these two sleeves a split sleeve 54 is secured
relation to the opening of the air- valve I |. ,The to the body 48 suitably by sweat-soldering. The .
fuel'valve 3| may have its?slotfllw proportionedso two halves_of;the__ sleeve 54. are machined very. 75;
creasing air speeds through the'throat. Obvi~
ously, more economical operation is insured if
7 5,
Hence, one may readily obtain whatever operat:
ing characteristics are desired. It is important
to note that in the operation of my carburetor
the full area of the ring II is subject toatmos
pheric pressure at alltimes whereby to, move the
ring according to ‘the. reduction in pressure in
2,135,539
accurately along the longitudinal edges to pro
vide an accurate metering slot 39 or 39', as the
,case may be, before the two halves are placed on
the body 48. Obviously, it is a simple matter with
this construction to‘ obtain a very accurately
measured slot 39 or 39’, because in the fastening
of the two halves, of the sleeve 54 to the body 48,
a f‘feeler” of the exact thickness of the slot de
sired can be entered between the edges where the
'10 slot is to be, while the halves are being sweat
soldered in place. Then, after that, the resulting
assembly can be machined or ground, and lapped,
if necessary, to bring it to the exact outside
diameter desired so as to ?t closely in the bore
15 .of the sleeve 41. The slot 39 obviously com
municates with the. passage 5|. A hole 55 in the
sleeve 52 communicates with the passage 5| so
that fuel from the outlet 30 can ?nd its way into
the passage 5| .and then through the slot 39 to
the port 45 when the valve 3| is opened by move
ment to theleft from the position illustrated in
Fig. 2. The amount of overlapping shown at 56
corresponds in its lineal'dimension to the amount
of movement required of the air valve ll before
air is delivered into the casing l4. In other words,
the 'fuel delivery commences at the same time
with the air delivery. The small collars shown at
51 and 58 on opposite sides of the port 46 have
a close working ?t on the valve, and in case any
30 fuel finds its way through the bushing 51, the
port 46 will drain such fuel from between the
bushings 5l-and 58, so that no fuel will drip in
side the casing 14 from the end of the bushing 49.
The projecting inturned end of the sleeve 52
forms a holder for a rubber ball 59 which is
pressed against the plug 43 when the valve 3| is
closed, thus tightly sealing the fuel outlet 39 to
prevent leakage. There is in fact a double seal
when the ball 59 is seated at 39, because of the
40 overlap at 56, previously referred to. This elimi
nates any danger of fuel dripping and going to
waste when the engine is standing idle. ,The rub
ber material employed for this packing member
59 will be of special composition not subject to
deterioration by contact with the fuel, such mate
rials being at present available, as is well known.
In conclusion, attention is called to the flap 60
pivoted at 5! and held closed under pressure of
the torsion spring 62 sealing the opening 63 in
the end of the carburetor casing I 4. This ?ap
valve is‘ merely a safeguard for the bellows l2 to
prevent any injury thereto in the event of a
back-?re. Obviously this valve 68 will remain
closed and prevent leakage of air during normal
55 operation when there is a reduction in pressure
in the casing-but will open instantly in the event
of a back-?re, whereby to relieve the pressure.
While I have shown the plate I I movable rela
tive to the head 9, it is of course evident that the
arrangement might be reversed, in which event
the plate would be rigid with the casing and the
head movable with one end of the bellows and
reversed end‘ for end from the position shown.
In like manner, while I have disclosed a slotted
65 fuel ‘metering plunger movable in a bushing, it
will be evident that this arrangement might also
be reversed and the movement be given to the part
surrounding a ?xed slotted part to uncover
different lengths of slot for the same purpose.
70 Then too, while the accelerator pedal would in
accordance with the present disclosure be con
nected to operate the throttle valve, an operative
structure would result if the throttle valve were
omitted and the accelerator pedal connected to
either the air valve H or fuel valve 3|.
3
It is believed the foregoing description conveys
a good understanding of the objects and advan
tages of my invention. The appended claims have
been drawn with a view to covering all legitimate
modi?cations and adaptations.
I claim:
1. A carburetor comprising a casing having an
outlet passage for conducting combustible mix
ture to an engine, a throttle valve therein, a ta
pered air metering head, an apertured air meter 10
ing valve plate wherein said head ?ts to form a
closure, said head and plate elements being rela
tively movable to provide therebetween a varia
ble air inlet opening for said casing, the movable
element being movable inwardly relative to said 15
casing under atmospheric pressure, a bellows in
terposed between said element and said casing,
and means for delivering liquid fuel for mixture
in said casing with the air admitted through said
inlet.
20
2. A carburetor comprising a casing having an
outlet opening for conducting combustible mix
ture to an engine, means for delivering air in
metered amounts to said casing to mix with fuel,
comprising a tapered air metering head, an aper
tured air metering valve plate wherein said head
25
fits to form a closure, said head and plate ele
ments being relatively movable to provide there
between a variable air inlet opening for said cas
ing, the movable element being movable inwardly 30
relative to said casing under atmospheric pres
sure, and a. bellows interposed between said ele
ment and said casing, a metering valve for de
livering fuel in metered amounts to said casing
to mix with the air, and means interconnecting 35
said metering valve and the movable element of
the aforesaid air metering means.
3. In a carburetor, a casing closed except for
an outlet opening to communicate with the in
take manifold of an engine, an air inlet valve on 40
a wall of said casing arranged to open under
atmospheric pressure when a reduction in pres
sure is created in said casing by said engine,
whereby to supply air to said casing in propor
tion to said pressure reduction, the valve com~ 45
prising an air metering valve head and an air
metering valve plate apertured to receive the
head, one of said parts being movable under
atmospheric. pressure in response to reduction
in pressure in the casing to admit a regulated
50
amount of air, and a fuel valve so constructed and
operatively connected with the movable mem
ber of said air valve to supply fuel to said casing
in predetermined proportion to the air for mix
ture with the air in the casing.
'
55
4. In a carburetor, a casing, a fuel metering
valve discharging therein comprising a tubular
guide, a hollow plunger recip-rocable in said guide
and having a longitudinally extending slot pro:
vided in the wall thereof, a fuel supply chamber 60
at one end of said guide, the same having a fuel
supply port in alignment with said plunger to
which liquid fuel is delivered under substantially
constant pressure, said plunger projecting into
said chamber and having constant communica
tion therewith throughout its range of endwise
movement, whereby the fuel discharged from
said plunger is metered according to the length
of slot uncovered at the other end of the. guide
when the plunger is moved endwise relative to 70
the guide, and a closure for said fuel supply
port on the adjacent end of said plunger, and
means for delivering air in proportionate amounts
for mixture in said casing with the fuel dis
charged from the fuel metering valve.
75
4
2,135,539
5. A structure as set forth in‘ claim 4, wherein
the parts are so arranged that the end of the
slot is inwardly spaced a predetermined distance
from the end of the guide when the supply port
is closed -by the closure, whereby to provide a
double seal against fuel leakage.
6. In a‘carburetor, a casing closed except for
an outlet opening to ‘communicate with the in
centric relation to said‘aperture, and wherein
said head is threadedly mounted in'said casing
for removal thereof independently of said plate.
11. A structure as set forth in claim'7, where
in the head is of uniform cross-sectionrat the
base thereof throughout a predetermined range
of initial movement of said plate, the aperture
in the plate receiving said uniform base por
tion with a'close working ?t.
take manifold of an engine, a suction operated
12. A structure as set forth in claim 7, where 10
air intake valve on said casing, the valve com
prising a stationary air metering valve head and in said head is of cylindrical form at the base
thereof throughout a predetermined range of
a relatively movable air metering valve plate ap
ertured to receive the head and movable under initial movement of said plate,’ the aperture in
atmospheric pressure in response to reduction ~ the plate being round and receiving said cylin
in pressure in the casing, a fuel metering valve drical portion with ,a close working ?t,v and 15
connected with the movable air valve plate and
arranged to be opened to an extent determined
by the'opening of the air valve, and a throttle
valve in the outlet opening independent of any
'
20 connection with the air and fuel valves.
"7. In a carburetor comp-rising a casing, an ‘air
metering valve comprising a stationary tapered
head on said casing, and an apertured valve plate
wherein said head ?ts to form a closure therefor,
said valve plate being’ movable in said casing as
a piston substantially without air leakage between
the plate and casing whereby to provide a varia
ble sized air inlet opening between the plate ap
erture and said head for the inlet of a variable
30 amount of air to said casing, said head being of
a predetermined shape in relation to the range
of movement of the plate whereby to afford pre
determined variation in the area of opening be
tween the plate and head in different positions of
35 the plate relative to the‘head, and means for de
livering liquid fuel for mixture in, said casing
with the air admitted by said air metering valve.
, 8. In a carburetor comprising a casing, an air
40
metering valve comprising a stationary tapered
head on said casing, an apertured valve plate
wherein said head ?ts to form a closure therefor,
said valve plate being movable in said casing as
a piston substantially without air leakage between
the plate and casing whereby to' provide a varia
ble sized air inlet opening between the plate ap
erture and said head for the inlet of a variable
55
wherein said head is threadedly mounted in said
casing for removal thereof independently of said
plate.
.
i
,
13; In a carburetor, a casing, a fuel metering
valve discharging therein comp-rising a'tubular 20
element, and a hollow rod element ?tting therein
with a close working ?t, the rod element having
a longitudinally extending slot provided in the
wall thereof, the rod having liquid fuel delivered
thereto under substantially constant pressure, 25'
said rod and tube elements being arranged to
have relative endwise movement, and the dis
charge of fuel being metered according to the
length of slot uncovered at the end of the tubu
lar element, and means for delivering air in pro
portionate amounts for mixture in said casing
with the fuel discharged from the fuel metering
valve.
‘
14. A structure as set forth in claim 13 where
in the rod element comp-rises an inner substan
tially cylindrical body having a longitudinal re
cess formed on one side thereof, and a sleeve
split lengthwise and ?tting on said body, the two
sleeve sections having ‘opposed longitudinal edges
disposed in spaced relation to form the longitu
dinal metering slot adjacent the longitudinal
recess, the recess constituting a fuel passage. ' V
15. In a carburetor, a casing, a fuel metering
valve discharging therein comprising a' tubular
element, a hollow rod element ?ttingrtherein
with a close working ?t, the rod element having
a longitudinally extending slot provided in the‘
amount of air to said casing, said head being of
a predetermined shape in relation to the range wall thereof, said rod and tube elements being
of movement of the plate whereby to afford pre . arranged to have relative endwise movement,
and the discharge of fuel being metered accord
determined variation in the area of opening be
tween the plate and head in different positions ing to the length of slot uncoveredrat the end
of the plate relative to the head, a metering valve of the tubular‘ element, means providing a fuel
for delivering fuel in metered amounts to said supply chamber at one end of said rod element,
the same having a fuel supply port‘in alignment
casing to mix with the air, and means intercon
necting said fuel metering valve and the air valve with the rod element to which liquid fuel is de
plate. ,
9.’ A structure as set forth in claim 7, wherein
said head‘ is removable from said casing inde
livered under’ substantially constantpressure, the
rod projecting into said chamber and having
constant communication therewith throughout
'its range of endwise movement, and a closure
stitution of a different shaped head affording a for said fuel supply port carried on the end of
60 different variation in the area of opening between said rod, and means for delivering air in pro
pendently of said plate, whereby to permit subl
the plate and head in corresponding positions of
the plate relative to the head.
10. A structure as set forth in claim 7, where
in the aperture in the plate is round and the head
65 is circular in cross-section and disposed in con
portionate amounts for mixture in said casing
with the fuel discharged from the fuel metering
valve.
7
,
JOHN B. SINDERSON.
40:
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