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Патент USA US2407536

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Patented Sept. 10, 1946
Harold A. Carlson, University City, and Olin J.‘
Eickmann, Normandy, Mo., assignors to Carter
Carburetor Corporation, St. Louis, Mo., a cor
poration of Delaware
Application June 24, 1943, ‘Serial No. 492,144
2 Claims.
This invention relates to carburetors for in
ternal combustion engines and consists particu
larly in novel means for influencing the character
of the fuel supplied by the carburetor in accord
ance with suction.
Where a function of the carburetor, such as a
fuel metering valve ‘or fuel pump, is controlled
by a suction responsive device, it has proved di?i
cult or impossible to provide for proper progres
sive operation of the device as the carburetor suc
tion varies. Where the device is made sufficiently
sensitive to provide for such operation, ?uttering
or “hunting” is likely to occur. Thus, such suc
tion responsive elements usually have been con
(01. 261-41).
?y choker valve H. Located below the choke in
the mixing chamber portion of the conduit, are a
series of venturis l3‘ and a butter?y throttle valve
I4 controlling the supply of mixture through the
outlet portion of the carburetor. At the bottom
of the carburetor there is provided a ?ange I15 for
attachment to an engine intake manifold (not
shown). ' The throttle valve is controlled by a le
versl?, perforated at IT for attachment of a link
l0 which extends to the usual-accelerator pedal’ in
the driver’s compartment. ' Adjacent the car
buretor barrel there is provided a fuel bowl 1-8
from the lower portion of which there projects a
casing I9 between which and the bodyof' the
structed to have only two positions of operation, 15 fuel bowl there is secured'a diaphragm 253; A
namely, the contracted or charged position at
metering pin 2! is secured to and projects'in
tained during idling and part throttle or economy
wardly from the diaphragm‘ through a main me
range operation, and the fully expanded or dis
tering ori?ce element 22, the pin being tapered
charged position which is reached at some lower
so as to vary the effective size of the ori?ce ele
point in the carburetor suction range or when 20 ment according to the position of the diaphragm.
the throttle is more fully open. However, it is de
Fuel for high speed operation is supplied
sirable to provide for progressive movement of -
the suction responsive element, particularly,
through the metering ori?ce element to‘ an up
wardly extending passage 25 and main nozzle
26 discharging into the smallest or primary ven
where‘ this element actuates a metering valve.
The use of a diaphragm accentuates the erratic 25 turi
operation of the suction responsive device be
cause of the change in shape of the exposed dia
.phragm in intermediate positions.
.It is the main object of the present invention
An interconnected idling system > is
shown including a metering tube 27 and com
municating passages 28 and 29 extending to idling
port 30 abreast the edge of throttle valve #4 when
closed. A screw‘ 3| carried by- throttle lever l6
to provide a suction responsive control for a car 30 abuts a ?xed stop 32 on‘ the carburetor barrel for
buretor function in which the suction responsive
adjusting the portion of idle port 38 exposed be
element is caused to move progressively and
low- the throttle valve during idling and, conse
stably from its high to its low suction positions.
quently, the idling speed. An idling economizer
A more detailed object is to provide means for
restriction is shown at 33 and idling air bleed re
moderating the effective suction applied to the ‘ strictions 34 and 35 are provided, the lattenopen
suction responsive element at periods of highest
ing into the air horn through a passaged rib- 35
carburetor suction and reducing the moderating.
and a tube 31.
effect as the suction drops so that the change in
The suction chamber 40 on the right hand side
suction applied to the suction responsive element
of diaphragm 20 is provided with'a coiledspring
willbe substantially less than exists in the car 40 4| which constantly urges the diaphragm toward
the left. A passage 42 connects-this chamber to
These objects and other more detailed objects
a port 43 communicating with the carburetor
hereafter appearing are attained substantially
mixture conduit posterior to the throttle. A sec
by the devices illustrated in the accompanying
ond passage 44 connects the diaphragm suction
drawing, in which: _
45 chamber to the carburetor air horn. During op
Fig. 1 is a top view of a carburetor embodying
eration, substantially atmospheric pressure exists
in the carburetor air horn and passage 44 is ex
Fig. '2 is a side View, partly in section of the
tendediinto' the air horn rather than outside the
carburetor and illustrating one form of the novel
carburetor so that air passing therethrough will
suction moderating device.
50 be strained by the usual air ?lter mounted on the
Fig. 3 is a detail section illustrating another
air horn. Passage 44 communicates with the dia
form of the device.
phragm suction chamber through’ a restriction
The carburetor illustrated is of the downdraft
45 and this restriction is controlled by a gradu
typev including an air inlet horn In at the upper
ated valve 46 which extends outwardly from dia
end of the mixture conduit controlled by a butter 65 phragm 20 and moves therewith. The diaphragm
is secured between cup washers 41 and 41*‘, the
above the port. In other words, throttle plate
former serving as a stop.
moderating valve 45 in Fig. 2 and, in the modi?
cation, the differences of suction in chamber 58
During operation, diaphragm 20 responds to
the differences in pressure between the outlet and
inlet portions of the carburetor mixture conduit
so asto cause the diaphragm to ?uctuate back
and forth against spring 4| and cause diiferent
portions of metering pin 2| to extend into the
ori?ce element 22 so as to vary the quantity of
|4 itself performs the function of the air bleed
will be substantially less than would be the case
if bleed port 52 were omitted. The shape and
exact position of port 52 may be varied, if desired,
to extend,v or increase the moderating effect
thereof upon the effective suction applied to the
fuel drawn through the metering ori?ce and, 10 diaphragm.
In both forms, the suction responsive element
consequently, the richness of the fue1 supplied by
shown as controlling a metering pin, but the
the carburetor. When the highest suctions exist
invention may be advantageously applied to a
posterior to the throttle, that is, during idling
similar element which controls another carbure
and early part throttle operation, diaphragm 20
will be drawn fully to the right with stop 41 en
gaging the inner wall of casing l9 so that a rela
tively large portion of pin 2| will be positioned in
ori?ce element 22. At the same time, a relatively
small portion of bleed controlling valve 46 will be
located in restriction 45 so that air bleed 44 will a
exert its maximum moderating effect upon the
suction transmitted through suction passage 42.
Spring 4|, of course, will be calibrated to provide
for a properly lean mixture in the economy or
part throttle range, and a considerably weaker 25
tor function, such as an accelerating pump. Ob
viously, a suction piston may be substituted for
the diaphragm and various features of the car
buretor such as the type of main nozzle and
idling system, the Venturi construction, etc., are
not essential. The invention may be modi?ed in
these and other respects as will occur to those
skilled in the art and the exclusive use of all
modi?cations as come Within the scope of the
appended claims is contemplated.
We claim:
1. In a carburetor, a mixture conduit having
spring 4| will be required than would be the case
a throttle therein, an idling fuel passage and a
where air bleed 44 were omitted.
second fuel passage discharging into said conduit,
As the accelerator pedal and throttle lever l5
a valve controlling the flow through said second
are moved to open the throttle, the suction in the
and a device for operating said valve
carburetor outlet will be decreased so that dia
including a suction chamber having a movable
phragm 20 will move to the left by spring 4| to
wall, spring means normally urging said Wall in
bring a smaller portion of metering pin 2| into
the direction to open said valve, and a suction
the metering ori?ce and enrich the mixture.’
passage connecting said chamber to said mixture
Coincidentally, a larger portion of bleed control
ling valve 45 will be moved into restriction 45 35 conduit, said passage opening into said conduit
through port means located partly posterior and
so that the moderating effect of the bleed air
partly anterior to said throttle when closed, the
entering through passage 44 will be reduced as
posterior part of said port means being at least
the diaphragm moves to the left. The effect of
- as large, effectively, as said anterior part, whereby
this variation of the effective air bleed is to sub
stantially reduce the suction changes applied to 40 the suction in said chamber decreases with the
suction posterior to said throttle as said throttle
the diaphragm which results in properly modu
is opened, said anterior port means being close
lated or progressive action of the diaphragm as
to the edge of said throttle so as to be increas
the carburetor suction drops. Consequently, it
ingly exposed to engine suction as said throttle
is possible to use a metering pin 2| having a plu
rality of graduated steps or a tapered portion 45 opens whereby the suction moderating effect
thereof is reduced.
instead of a pin having merely lean and rich
2. In a carburetor, a mixture conduit having a
positions. The effective sizes of passages 44 and
throttle therein, an idling fuel passage and a
42 can be adjusted to provide for the desired
second fuel passage discharging into said conduit,
movement of the diaphragm responsive to suc~
tion changes in the carburetor.
50 and a device for controlling the flow through said
second passage including a suction chamber hav
In Fig. 3, diaphragm suction chamber 50 is
connected to the carburetor mixture conduit by ' ing a movable wall, spring means normally urging
said wall in the direction to enrich the fuel sup
means of a passage 5| opening into the conduit
ply, and a suction passage connecting said cham
through a pair of ports 52 and 53.' Port 52 is
preferably in the form of an elongated slot and ' her to said mixture conduit, said suction passage
opening into said conduit through suction port
is positioned so as to be wholly or mostly anterior
means located wholly posterior to said throttle
to the edge of throttle l4 when fully closed to its
when closed and air bleed port means located
idling position. Idling port 36 is shown slightly
slightly anterior to said throttle when closed, said
spaced from port 52.
In this form, upper port 52 acts as an air bleed, 60 suction port means being of greater effective area
than said air bleed port means whereby, during
when the throttle is closed, for moderating the
operation, the suction in said chamber decreases
suction effect transmitted to the diaphragm
with the suction posterior to said throttle, as said
through port 53. As the accelerator pedal and
throttle is opened, and the suction moderating
throttle lever are moved to open the throttle,
plate l4 moves upwardly along port 50 and pro 65 effect of said air bleed port means is coinciden
tally reduced.
gressively exposes less of the area of this port to
the relatively high pressure above the throttle so
that the bleeding or moderating effect thereof
will be reduced until the edge of the throttle is
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