Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1046364 - :
The present invention is related to a fuel flow control
device adapted to replace the conventional idling jet or pilot
jet used in a manner well known per se on the carburetor of an
internal combustion engine or motor, such as an automobile motor,
which carburetor comprises a fuel inlet conduit connecting the
float chamber of the carburetor to a threaded hole adapted to
receive selectively said idling or pilot jet or said fuel control
device, and a low-pressure conduit provided between the carbureting
chamber of the carburetor and the air-fuel mixture inlet of the
combustion engine. ~ :
The fuel flow control device according to the present inven-
tion comprises a body provided with an externally threaded portion
adapted to be screwed into said threaded hole, said body further
comprising adjacent its end adapted to be introduced into said
threaded hole a substantially cylindrical chamber defining a
first valve seat at one of its ends into which opens a calibrated
: passage adapted to connect said chamber to said fuel inlet conduit,
sàid chamber defining at its other end a second valve seat
communicating with laterally disposed passages adapted to be inter~
posed ;n said low-pressure conduit, a valve member movably mounted
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; within said chamber and cooperating alternatively with said first
~ and second valve seats, and control means connected to said valve
; member in such a manner that the latter is not in contact with
;~: either one of said first and second valve seats when said internal
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~ 25 combustion engine operates at idling speed, while said valve
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member engages said first valve seat when said engine
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operates at an increased speed, whereas said valve member
engages said second valve seat when said engine operates at
a decreased speed.
It will be understood that, due to this arrangement,
S fuel is fed through the novel control device to the engine only
when the latter operates at idling speed, whereas said control device
decreases or interrupts the fuel flow between the carbureting chamber
and the engine when the latter operates either at increased or .
at decreased speed. Thus the novel control device allows
considerable amounts of fuel to be saved~and the combustion to b~i~rro~e~
In one embodiment of the instant invention, said second valvë
seat is connected to an axial bore opening into a cylindrical
space defined within said body, which cylindrical space has a
diameter larger than that of said chamber, while said valve member
is constituted by a valve head having opposed first and second end
faces cooperating with said first and second valve seats, respec-
tively, said valve head being integrally connected to one end of
a cylindrical stem coaxially extending through said axial bore and
into said cylindrical space in said body, the other end of said
stem being provided with a piston-like member submitted to the ~:
: action of a return spring mounted within said cylindrical space,
said laterally disposed passages opening into said axial bore at
substantially diametrically opposed locations thereof, the cross-
sectional dimension of said stem being smaller than that of said
cylindrical bore, and the force of said return spring being such that
under low-pressure conditions occurrlng when said engine operates
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at idling speed, said valve head is placed in a position
between said first and second valve seats, with none of said
end faces of said head in contact with the associated valve seat,
while under low-pressure conditions occurring when said engine
operates at an increased speed said first end face of the valve
head engages said first valve seat, whereas said second end face
of the valve head engages said second valve seat under low-pressure
conditions occurring when said engine operates at a very low speed.
In a particularly advantageous embodiment of the instant
invention, the device comprises means for introducing supple-
mentary air into the inner space of said device.
These means for introducing supplementary air are constituted,
in a preferred embodiment, by at least one through-hole provided
in said piston-like member and extending therethrough in a direction
substantially parallel to the longitudinal axis of the same.
In Yet another advantageous embodiment of the invention, means
are provided for submitting said valve head and said stem integral
therewith to a rotational motion.
The above mentioned means for rotating said valve head and stem
are advantageously constituted by conveniently shaped blades pro-
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vided at the periphery of said stem and adapted to rotate the latter
under the effect of the air flow;ng through the inner space of
the device.
The invention will now be described in more detail with
reference to the appended drawings. It should be well understood
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~ that the description herein after is given by way of example only,
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and not by way of limitation of the scope of the invention.
Figure 1 shows an embodiment of the fuel flow control device
according to the invention, in longitudinal section.
Figure 2 shows another embodiment of the novel device, also in
longitudinal section.
Figure 3 is a sectional view of a detail of the novel device
according to a particular embodiment.
Figure 4 is a longitudinal section of the stem and the valve
head integral therewith, as used in one embodiment of the novel
device.
Figure 5 is a schematic end view of the valve head shown in
Figure 4.
The fuel flow control device shown in Figure 1 comprises a
body 1 provided with an external threaded portion 2 allowing the
body 1 to be screwed into a threaded hole 3 of a carburetor 4
(shown schematically), which hole 3 is normally provided for receiv-
ing, in a manner known per se, an idling jet or pilot jet. The
carburetor 4 is associated to an internal combustion engine, such
as an automobile engine.
Body 1 has at one of its ends a cylindrical portion 6 onto which
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is fitted a tubular casing 7 provided at one of its ends with a
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valve seat 8 into which opens a calibrated passage 9, while adjacent u
; its other end, said tubalar casing 7 is provided with two diametrically
opposed, laterally disposed passages 10 which are in register with
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~ ~ 25 corresponding lateral passages 5 provided in the cylindrical portion 6.
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The free end of cylindrical portion 6 is provided with a
valve seat 12, and body 1 comprises a cylindrical bore 13 extend-
ing ;n an axial direction and opening into a cylinder 14 the
inner diameter of which isslightly greater than that of tubular
casing 7.
A piston 15 ;ntegral with a stem 16 is slidingly mounted in the
cylinder 14, said stem 16 being capable of moving slidingly in
the cylindrical bore 13 and being provided at its end opposite
the piston 15 with a valve head 17 having a configuration such that
it forms a first valve surface 18 adapted to cooperate with the
first mentioned valve seat 8, and a second valve surface 19 adapted
to cooperate with the second valve seat 12.
When the device is mounted on the carburetor the calibrated
passage 9 ;s in register with the fuel inlet conduit ? of the
carburetor which is connected to the carbureting chamber of said
carburetor, while the lateral passages 5 ~Pelocated in a conduit 21
one end of which opens into the upper part of the carbureting
chamber 22, said conduit 21 opening at its other end into the inlet
below the throttle 23, a taper-end screw 24 being provided in the
resulting flow path for adjusting the fuel flow rate during the
operation of the engine at idling speed.
As shown in the Figure, stem 16 has a diameter smaller than the
inner diameter of bore 13, so as to be able to slide freely while
defining an interval between said stem and the inner wall of said
bore for allowing air to flow through said bore.
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A compression spring 25 is mounted within cylinder 14;. this
spring is selected and dimensioned in such a manner that, when
the engine does not operate, valve head 17 is located at a point
between the ends of tubular casing 7.
S The device described herein above operates as follows:
When the internal combustion engine is started, air is drawn
into conduit 21 and flows through the passages 10, thus producing
a low pressure by which fuel is drawn into the device through
calibrated passage 9. This low pressure also acts on piston 15
which tends to move toward the bottom of cylinder 14; however
spring 25 counteracts this tendency, whereby valve head 17 is held :
in an intermediate position such as the one indicated in Figure 1.
In this position the fuel and the air-fuel mixture are free to
flow through the control device. . ..
lS When the speed of the engine is increased, the pressure pre-
vailing inside the control device still decreases in such a manner
that the resulting low pressure has an effect stronger than that -
of spring 25; consequently piston lS then is displaced in the
direction indicated by arrow f, and valve surface 18 engages valve
seat 8, thus preventing the fuel from flowing into the control
device.
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- When the speed of the engine is decreased the pressure inside
the control device is increased, so that spring 25 expands and
pushes piston 15 with a force sufficiently high to cause valve
surface 19 to engage valve seat 12, thus preventing the fuel from
being drawn into the device through the calibrated passage 9.
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When the internal combustion engine is again operating at a
speed close to its idling speed, the low pressure inside the
control device causes piston 15 to move against the force of
spring 25, thus allowing fuel to be drawn into the device again.
It will be understood from the preceding that the novel device
allows considerable amounts of fuel to be saved, on the one hand
when the speed of the engine increases, as the device then cuts
off the fuel flow, and on the other hand when the speed of the
engine decreases, as fuel is allowed to be admitted only after
the speed of the engine corresponds again to the idling speed.
The embodiment shown in Figure 2 has a structure fundamentally
similar to that of the embodiment described herein above, and
consequently the same reference numerals have been used in both
Figures 1 and 2 for designating identical or similar parts.
However the embodiment of Figure 2 is distinct from the preceding
one in that it comprises means for introducing supplementary air
into the control device.
In one variant the supplementary air is introduced into the
cylindrical bore 13 through at least one hole 26 provided in the
wall of the body 1.
` ~ It has been observed that, due to the introduction of supple-
mentary air, the pollution of the atmosphere by the exhaust gases
of the associated internal combustion engine was considerably
reduced. For example, it has been experimentally established that,
`~ 25 for a given automobile engine equipped with the novel control
: ~ device provided with supplementary air inlet means, the carbon
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~ 046364
monoxide content of the exhaust gases was 0.2%, as compared
to 4% for the same engine equipped with a conventional idling
or pilot jet.
In another variant of the embodiment shown in Figure 2
supplementary air is introduced into the device through at least
one through-hole 15a provided in piston 15.
The assembly comprising piston 15, stem 16 and valve head 17
may be rotated by convenient means with a view to allowing the -
fuel to be more uniformly distributed on the surfaces it encounters
when flowing through the device, whereby a more efficient
evaporation is achieved. The rotational motion of said assembly
may be obtained advantageously by means of conveniently shaped
blades or fins provided on the periphery of stem 16, said blades
being submitted to the effect of the air stream flowing through
the device, so as to act like the blades of a turbine or the like.
In another embodiment, the helical shape of the spring 25 is
used for rotating the above mentioned assembly; indeed, when
supplementary air is admitted through hole 15a (Figure 2), this
air then acting in a well known manner on the helical surface
defined by the spring and thus causing the same to rotate.
Advantageously the end of the stem provided with piston 15
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is visible to the user, thus enabling the latter to check the
satisfactory operation of the device.
As shown in Figure 4, the free end of the valve head 17a
integral with stem 16a may be provided with projecting portions
17b which prevent the valve head from sealing the passage 9
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when the opening stroke of the movable assembly is too long.
These projections, an end view of which is represented in Figure
5, are also useful in that they cause the fuel to rotate, when
the above mentioned stem and valve head assembly is rotated as
S described, thus enhancing the above mentioned advantageous
effects of the rotation of said assembly.
It will be understood that another advantageous effect of the
rotational motion of the stem and valve head assembly resides in
the self-cleaning action produced by this rotationi indeed, by -
10 rotating as described, the said assembly prevents solid impurities
from being accumulated within the control device.
Figure 3 shows an embodiment wherein the tubular casing 7 of
Figures 1 and 2 is replaced by a portion 7a integral with the
remaining portion of the body la. This Figure also shows a flow
15 diagram of the device, as arrows indicate the inlet and outlet
of the various fluids. Arrow g indicates the inlet flow of
supplementary air; arrow h indicates the inlet flow of normal air;
arrow i indicates the outlet flow of fuel-air mixture; and arrow
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k indicates the inlet flow of fuel.
It should be noted that in all the embodiments of the device
according to the invention, the fuel, when penetrating the device
through calibrated passage 9, encounters the valve head 17 before
it flows along the portion of the stem 16 adjacent said valve
head. Consequently the fuel presents a considerable surface area,
25 which enhances the vaporization in the air circulating in this
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zone of the device.
The invention is not limited to the embodiments described
and shown herein. As one skilled in the art will easily under-
stand, many modifications may be envisaged within the scope of
S the invention, particularly as defined in the appended claims. ;~
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