US2082293A - Carburetor - Google Patents

Description

T. LINGA CARBURETOR June I, 1937.

Filed June 12, 1935 4 Sheets-Sheet 1 w w w w w w w n 6 1 m T W 3 5 mm iw A \Q 7 I, u f/ Z 1 1 H 1 .h WNW F a 7 H June 1, 1937. T. LINGA 2,082,293

CARBURETOR Filed June 12, 1935 4 Sheets-Sheet 4 JIwe/ ZYZfi forijorn Zagga, 4

Patented June I, 1937 UNITED STATES PATENT OFFICE 17 Claims.

The present invention concerns carburetors and pertains more particularly to that type of construction into which the liquid fuel is elevated from a lower supply-tank by reason of the suction or subatmospheric pressure present in the carburetor.

A leading aim of the invention is to provide an improved structure of this kind which will more efficiently meet the strict and exact requirements of a carburetor of the fuel-lift style, and, to this end, various changes and betterments in the several parts of the appliances have been devised which singly and cooperatively aid in producing the result sought for.

These features of novelty and advantage are pointed out in the following detailed description and are set forth in the appended claims, but preliminarily it may be mentioned that they relate more particularly to an improved type of air-admission valve, an air deflector under such valve to reduce its Venturi efiect, an air-bleeder to maintain the desired fuel-feeding head in the carburetor, a weight and asociated float acting on the air-valve, an auxiliary air-bleeder a to obtain fuel adjustment, a supplementary fuelwell functioning during acceleration, and a thermostatic means governing the action of the carburetor.

In order that those skilled in this art may readily understand the invention and the numerous benefits accruing from its employment, in the accompanying drawings, forming a part of this specification and to which reference should be had in connection with the following detailed description, a present preferred embodiment of the invention has been illustrated in detail, and, for simplicity, like reference numerals have been employed to designate the same parts throughout the several views.

4 In these drawings:

Figure 1 is a vertical section through the carburetor;

Figure 2 is a horizontal section through the Venturi construction on line 22 of Figure 1;

Figure 3 is a fragmentary horizontal section on line 3-3 of Figure 1 showing the block or partial obstruction adjacent the air-valve of the main induction-passage;

Figure 4: is a vertical cross-section on line 44 of Figure 1;

Figure 5 is an enlarged detail section showing the tapered pin or rod controlling the admission of supplemental air intothe upper portion of the float-chamber;

Figure 6 is a fragmentary section on line 6-6 of Figure 7 and illustrates the manually operable means for enriching the mixture, as during starting of the engine;

Figure 7 is a section through such enrichment structure on line 1---'! of Figure 10;

Figure 8 is another adjacent section on line 8-8 of Figure 10;

Figure 9 is a partial upright section on line 9-9 of Figure 10 depicting the means for enrichment of the mixture during acceleration, the portion of the venturi illustrated not being in its correct position;

Figure 10 is an elevation of the carburetor as viewed from the rear of Figure 1;

Figure 11 is a thermostatic control for the carburetor, and

Figure 12 is a diagrammatic view of the device showing in one illustration the various chambers, passages and valves entering into the construction.

Referring to these drawings, it will be perceived that the carburetor is composed of two main members 2| and 22 held together by a hollow post 23 located centrally of the floatchamber 24 and screwed at its top end at 25 into the upper element 2|, its lower end being threaded and fitted with a tightening nut 26, the companion members of the carburetor being additionally secured together by an appropriate cap-screw 21, a gasket 28 being interposed between the parts 2| and 22 to make a substantially air-tight connection.

When thus assembled, the structure has a main induction-passage 29 open at its top end at 3| to the atmosphere and adapted to have its lower open end 32 connected to the internalcombustion engine with which the carburetor is designed to be associated.

Near the upper end of such induction-passage 29 it is fitted with an air-inlet valve 33 of the butterfly-type mounted on a rock-shaft 34, the latter being positioned somewhat oif center or at one side of the axis of the passage, as illustrated in Figure 1, so that the valve is not in balance, whereby if the valve were free to turn, it would automatically open.

This air-admission valve is out of balance due to the fact that its shaft 34 is off center with the result that, when the internal-combustion engine is running, the pressure of the external atmosphere will be greater on the larger section of the top of the valve than on the other or companion smaller section, and consequently, the valve will open more or less according to the demand of the engine.

As is clearly illustrated in Figure 1, such valve is reversely curved somewhat at its opposite edges and the purpose for this is that unless that part of the valve at one side of the shaft, which is the larger of the two, is curved outwardly or upwardly as shown, the valve will not open fully without a greatly augmented difference in pressures between its upper and under sides.

The slight downward curvature of the edge portion of the smaller section of the valve is provided for a somewhat different object, namely, in a measure to decrease a certain aspirating eifect or action which is created when the valve is partly open.

One side of the induction-passage 29, directly under the smaller part of the air-inlet valve 33 at one side of its shaft, is fitted with a stationary lug, block or barrier 35 of the shape in vertical section presented in Figure 1 and fastened in place by securing screws 36, 36.

This block or member 35 is employed for a somewhat similar aim, that is, to decrease the Venturi action at the smaller part of the valve when it is partially open by acting as a baffle or impediment to churn up or mix the entering air and in a measure reducing the partial vacuum beneath that portion of the valve by reason of so doing.

Also mounted in the induction-passage below the air-inlet valve and its associated block 35 is a member 31 having a central, downwardly-directed, double or duplex venturi 38, 39, and below the latter the induction-passage is equipped with the customary throttle-valve 4| on its operating shaft 42.

Element 31 below the smaller venturi 38 has a lateral passage 43 connecting the venturi 39 with the large lower end of a supplemental or auxiliary inclined smaller venturi 44, 45, the upper end of which is connected to the outer atmosphere through a chamber 46 and a slot 41 through its wall communicating with the passage 29 above the air-inlet valve 33.

An upstanding lug 48 on the heavier, larger section of valve 33 is joined by a link 49 to the end of a lever 5| fulcrumed at 52 and accommodated in the slot 41, the opposite bifurcated end of the lever being located beneath the head 53 of a nut 54 adjustably threaded on the top end of the long stem 55 of a fuel-metering valve 56 co-acting with its valve port or orifice 51, the stem of the valve being located in the central bore 58 of the post 23 and the valve port being in the lower end of such post.

A nut 59 screwed into the upper end of the post has a calibrated central bore of such size that the elongated valve-stem 55 is just slidable through it without side play.

Near its lower end the valve-stem 55 extends through a vertical opening in a cross-bar 6| (Figs, 1 and 4) fastened at its ends by screws 62, 62 to a ring-weight 63 adapted to travel up and down in a lower cylindrical portion 64 of the fuel-chamber 24, the stem being pinned at 65 to such cross-bar, whereby the element 63 constitutes a weight mounted on the valve-stem and the parts 63, 64 comprise a dash-pot preventing fiuttering or chattering of the air-inlet valve 33.

To accommodate such cross-bar, the post 23 is slotted vertically at 66 with the slot intersecting the post-bore 58, thus providing means whereby the valve-stem and its weight may move up and down with respect to the fixed or stationary post.

From what precedes, it will be clear that when the air-admission valve 33 opens under the influence of the suction of the engine, it raises the fuel-metering valve 56 through the action of lever 5|, the object or purpose of the construction being to cause the valve 33 and the fuelmetering valve 56 to operate in direct conjunction or association with one another.

The liquid fuel, as presented in Figure 1, is admitted into the fuel-chamber 24-64 through an inlet-conduit 61, ball-check valve 68, screen 69, passages H, 12, and fuel-inlet valve 13 at the top of the chamber and which tends to open downwardly by its own weight but which is adapted to be raised and closed by a fioat 14 in the chamber 24 when it contacts therewith, the fioat surrounding and being guided in its vertical movements by the cylindrical post 23. By this simple means the fiow of fuel into the chamber 24 is efficiently controlled.

The fuel in the lower part of the float-chamber 24 has access through the slot 66 to the top portion of valve 56, and, if such latter valve is open, the fuel flows down through the port 51 at a metered rate.

Orifice 51 communicates with a chamber 15 in. the lower part of post 23, the bottom of the chamber being closed as illustrated by the nut 26, the top of such chamber communicating through two upright passages 16, 16 in the post with an annular compartment 11 in casting 2|, such chamber 11 in turn being joined to another annular chamber 18 through a passage 19, chamber 18 being in direct communication at 8| with the throat of the venturi 44, 45.

Thus the fuel delivered from the float-chamber 24 into the lower chamber 15 through the valve 56, 51 is drawn up or sucked up through the passages 16, l1, l9 and 18 into the venturi 44, 45, the greatest degree of suction in the carburetor being at the point 8|.

In order to lift the fuel from its supply-tank, not shown, into the float-chamber 24, it is, of course, necessary to apply suction or develop a subatmospheric pressure in the latter, and this isaccomplished by mounting in the wall of the float-chamber a so-called jet or plug 82 having a metered orifice through it in direct connection with an aperture 83 opening into the Venturi passage 44 at a point somewhat distant from the Venturi throat 8|, so that the suction imparted by the venturi through the united openings 83 and 82 into the float-chamber is less than the suction communicated from the Venturi throat at 8| to the post passages 16, 16.

Opening or port 83 is so located with relation to the venturi 44, 45 as to give a correct fuelfeeding head when the engine is idling, at which time the air-admission valve 33 and the fuelmetering valve 56 are approximately in the positions indicated in Figure 1.

As the air-inlet valve 33 and its correlated fuelmetering valve 56 open progressively more and more under greater engine demand more fuel is introduced into the Venturi throat 8|, causing a reduction of or deadening effect on the suction at such throat with but little effect, however, on the suction at orifice 83, thus reducing the fuelfeeding head, and, to remedy or to compensate for this condition the stem of the fuel-metering valve 56 is properly tapered at its portion 84 which slides up and down through the calibrated opening or port 85 through the nut 58 (see Figs. 1 and 5).

The parts of the carburetor are shown in engine-idling positions in Figure 1, the upper portion of the valve-stem 55 under such circumstances filling the bore of nut 59 snugly or closely enough so that very little air, if any, can leak into the fuel float chamber 24 between the elements 55 and 59. 7

When the increased engine requirement occurs, the fuel-metering valve 56 lifts automatically by reason of its mechanical connection with the opening valve 33, and its stem '55 may then occupy the position depicted in Figure 5, which permits an augmented volume of air to flow through the annular space 85 between the elements 55 and 59 into the upper portion of the float-chamber 24 through lateral holes 86, 8 6 connecting the central bore 58 of post23 with the upper part of the float-chamber above the fuel-level.

By properly forming or calibrating the taper 84 of the valve-stem and the complementary orifice through the jet-member 82, the needed fuelfeeding head is maintained throughout the range of action of the carburetor.

This self-feeding carburetor is so constructed that there is always adequate suction in the floatchamber 24 to lift the fuel thereinto from a supply-tank or reservoir usually located at some distance below the carburetor in the modern automobile.

In addition to elevating the fuel from the tank or reservoir into the float-chamber, it is necessary to maintain a somewhat greater suction at the'Venturi throat 8| in order to further lift the fuel from the float-chamber into the air stream flowing through such throat.

The greatest suction in the carburetor is created at throat 8| and it is communicated to the fuel-metering orifice or valve-port 51 through passages I8, 19, I6, I5, the actual or effective fuel-delivering head being, therefore, the suction at 8| less the suction in the float-chamber 24, minus the suction required to raise the fuel from the fuel-level in the float-chamber up into the throat 8| of the small venturi 44, 45.

In order to secure better acceleration of the automobile equipped with the carburetor, one side of the float-chamber 24 of the latter (see Fig. 9) is fitted with a fuel-pump comprising a stem or rod 9| carrying a piston or plunger 92 on its lower end which is adapted to slide in an'upright cylinder 03 whose bottom end has a port 94 opening into the lower part of the float-chamber, such port being equipped with a disc check-valve 95. 1

Stemv 9| extends up through and is slidable in the bore of a nut 96, and, above the latter, the stem has spaced collars or enlargements 91, 9'|-- between which is accommodated a split or bifurcated, rounded end 98 of a lever 99 (see Fig. 10) fulcrumed at |0|, the opposite end of the lever being joined by a link I02 to an arm I03 on shaft 42 of the throttle-valve 4|.

Accordingly, when the throttle-valve is being closed the plunger 92 slides upwardly in its cylinder, drawing fuel from the float-chamber through the port 94 into the cylinder below the plunger, and, when the throttle-valve is opened, the plunger is forced downwardly to expel the contents of the cylinder below it.

The lower part of cylinder 93 is connected by passages I04, I05, I06 to the interior of a -jetmember I01 having a metered orifice I08v communicating through a registering aperture I09 with the interior of Venturi passage 44 atab'out the same distance from the throat 8| as is the port 83.

As is clearly illustrated, the bore of member I01, through a passage III connects with the lower portion of a fuel well or storage compartment 2 joined at its upper portion to Venturi passage 44 by anopening II3.

Passage I04|05 has a check-valve I4 closing by gravity and opening when the pump-plunger descends to allow the flow of fuel upwardly past it. 4

From the foregoing, it will be apparent that, whenthe throttle-valve is opened, the pumpplunger descends forcing the liquid below it up through the passages'I04, I05, I06, I09, I09 into the smaller venturi 4445, the check-valve 4 closing assoon as the upward pressure on it terminates. l

I Some of such pumped fuel passes directly into the, venturi to enrich the mixture, whereas a part of such fuel is forced into the well II2 from which it subsequently and gradually descends into the jet-member flowing out through openings I08, I09 into the venturi, thus prolonging the otherwise too short enrichment of the mixture.

The purpose of this particular construction is that it is not desirable to supply all of the accelerating fuel into the engine instantaneously, the best and most eflicient enrichment being obtained when a shot of fuel is given to the engine momentarily upon the opening of the throttle valve and an enriched mixture is fed to the engine for a few seconds thereafter.

- This protracted or lengthened fuel-enrichment from the well is capable of accomplishment because of the opening 3 between the venturi and the well, the suction at the passage I I3 being less than that at the orifice I08 by reason of their different locations along the length of the venturi.

- Obviously, when the throttle-valve is again closed, plunger 92 rises, valve 95 opens, and fuel flows from the float-chamber into the chamber 93 ready for the'next descent of the plunger and its expulsion inv the manner and for the purpose alreadyset forth. 1

In a part I 2| of the upper casting 2|, a tapered bearing I22 is provided for" the reception of a cone-valve member I 23 having an opening I24 in its smaller end and into which fits the terminal portion of a rod I25 flattened for a part of its length [on one side so. that it may fit in the correspondingly-shaped opening I24 and be capable of turning the valve-member I23 insuch bearing. l

Thisrod or flexible shaft I25 is not shown in Figure 10 for the sake of clarity of illustration of the other parts of the appliance, but it is indicated in Figure 6 and it extends to a convenient point in the automobile within reach of the driver, and such end is fitted with a knurled knob I26 by means of which the rod and its valve-member may be readily turned manually.

The exterior of the larger portion of "the convalve member I23 has an arcuatepassage or port I 21 (Figs. 6 and '7) adapted, in a certain position, to connect a passage I28 communicating with chamber 11 with an upright passage I29 openingat its lower bent end into the interior of the float-chamber 24.

When the valve-member I23 is in the position shown in Figure '7, the fuel mixture, as during starting of I the engine in cold weather, is enriched by 'reasonwofxthe suction in compart ment l1 drawing additional fuel into such chamber by the connected conduits I28, I21, I29 and from which chamber it passes along with the other fuel into the subsidiary venturi 44, 45.

The smaller portion of valve-member I23 on its outer surface has a circumferential groove I3I (Fig 8) of graduated depth, its deeper end being connected by an aperture I32 to the hollow interior or bore I33 of the member I23 which at one end at I34 is open to the atmosphere.

Groove or channel I 3I is in the plane of a right-angle passage I35 opening into the bearing or valve-seat at one end and connecting at its other end with the interior of the float-chamber 24 above the fuel-level therein, this construction affording a variable or adjustable air-bleed from the atmosphere into the float-chamber for the purpose of increasing the fuel-feeding head.

In its normal position, corresponding to ordinary running conditions of the coupled engine, the cone-valve member I23 is in such position that both the auxiliary fuel-delivery opening from the float-chamber to the venturi and the air-bleed from the atmosphere into the floatchamber are closed.

In starting and warming up the engine, however, the operator by turning the knob I26 correspondingly turns the valve-member I23 to first open gradually the air-bleeder passage from the outer air into the float-chamber to increase the fuel-feeding head, and, then by further turning, opening the supplementary associated fuel-conduits to deliver more fuel into the smaller venturi from which, of course, it flows down into the induction-passage. Also, to compensate for colder and hotter weather as well as to improve the mixture during starting of the engine and during its initial warming-up period, the carburetor is equipped with a thermostatic appliance involving an upright passage I4I (Fig. 11) leading into the upper part of the float-chamber, its lower portion I42 being of reduced diameter, and the lower part of the larger passage is open to the outer air through a side aperture I43.

When air is bled into the float-chamber through the conduit I43, I4I the fuel-feeding head is correspondingly increased with accompanying enrichment of the mixture.

A cylindrical stem I44 has a conical valvehead I45 at its upper end, such stem having a different coefficient of expansion by heat from that of the metal surrounding it.

In installing the stem and its valve, the lower part of the stem is fitted into the bore I42 as a press fit, and it is forced down until its upper valve-head rests against its seat at the top end of passage I.

This stem having less heat expansion than the encompassing metal, when the carburetor warms up in service it will, by engagement with the valve-head, slide the valve-stem in its tight bearing an amount determined, of course, by the degree of expansion of the carburetor body.

When the carburetor cools down, the valve remains somewhat open, thus admitting air into the float-chamber to enrich the mixture by increasing the fuel-feeding head, such enrichment being gradually reduced and finally terminated as the carburetor expands, causing the closing of the valve-port.

The valve and its stem having once been properly installed, they automatically assume and maintain their final position.

The operation of the carburetor is in general substantially as follows:

Assuming that the engine served by the carburetor is cold and is about to be started, the operator turns the handle or knob I26 and the shaft or stem I25 to bring the cone-valve I23 into the position shown in Figs. '7 and 8, wherein the supplemental fuel-conduit is put into direct connection with the chamber TI.

When the valve is in this position, the outside air connection is established through the united conduits I34, I33, I32, I3I, I35 with the inside of the float-chamber above its fuel-level.

These two connections cause a substantial enrichment of the fuel-mixture, allowing the engine to start promptly, and after normal running conditions have been established, the valve handle I26 is turned back to its original position, closing the two enrichment connections referred to.

Of course, it is not necessary in all cases to make these two connections to their maximum extent, nor is it essential that both of them be made, since the one can be made operative without making the other substantially so.

Air-inlet valve 33 opens automatically more or less when the engine is running and in accordance with the engine demand, the opening action of the valve, through the mechanical connection shown, lifting the fuel-metering valve 56 to act in conjunction with the valve.

Weight 63 tends to close valve 33 and it is of such amount or size that certain predetermined suctions will be created in the two venturis 38-39 and 44-45, that of the latter being greater than that of the former, and applied to the float-chamber through port 83 and the orifice of member 82.

If the suction thus established or created in the chamber 24 is not sufficient to lift fuel from the lower-level fuel-reservoir into such chamber, the fuel-level in the float-chamber will gradually descend, and, the float will correspondingly lower until. it rests on the cross-bar 6| of the weight, thereby adding all or a portion of its weight to the member 63, thus effecting an increased suction in the venturis and in the float-chamber until a point is reached which is adequate to elevate the fuel into the chamber.

Obviously, as the fuel-level in the chamber ascends, the float rises and relieves the member 63 from such supplemental or auxiliary weight, thus restoring the operation of the carburetor to that which it was originally.

From what precedes, it will be clear to any one skilled in the art that the structure is such and its manner of functioning is such that the fuel will be lifted into the carburetor in a way for the satisfactory performance of its usual operation regardless of the varying conditions under which it must function.

I claim:

1. Ina carburetor having a main inductionpassage, the combination of a fuel-chamber, means to feed fuel into said chamber, means to deliver fuel from said chamber into said induction-passage, a fuel-valve in said delivery means, an unbalanced air-admission valve for said passage mounted to turn about an off-center axis, the smaller section of said valve at one side of said axis being curved inwardly to reduce the aspirating effect of the valve when it is partially open, means restraining the opening turning of said air-admission valve, and means connecting said air-admission and fuel valves whereby they open and close conjointly.

2. In a carburetor having a main inductionpassage, the combination of a fuel chamber, means to feed fuel into said chamber, means to deliver fuel from said chamber into said induction-passage, an unbalanced air-admission valve for said passage mounted to turn about an offcenter axis, the larger of the two sections of said valve at one side of said axis being curved outwardly to increase the opening effect of the atmosphere on the valve, the smaller of the two sections of said valve at the opposite side of said axis being curved inwardly to reduce the aspirating effect of the valve when it is partially open, and means restraining the opening turning of said valve.

3. In a carburetor having a main inductionpassage, the combination of the fuel-chamber, means to feed fuel into said chamber, means to deliver fuel from said chamber into said induction-passage, a fuel-valve in said delivery means, an unbalanced air-admission valve for said passage mounted to turn about an oifcenter axis, the larger of the two sections of said valve at one side of said axis being curved outwardly to increase the opening effect of the atmosphere on the valve, the opposite smaller section of said valve on the other side of said axis being curved inwardly to reduce the aspirating effect of the valve when it is partially open, means restraining the opening turning of said air-admission valve, and means connecting said air-admission and fuel valves whereby they open and close conjointly.

4. In a carburetor having a main inductionpassage, the combination of a fuel-chamber, means to feed fuel into said chamber, means to deliver fuel from said chamber into said induction-passage, an unbalanced air-admission valve for said passage mounted to turn about an oflcenter axis, a bailie in said passage inwardly from and substantially in register with the smaller section of said valve at one side of said axis, and means restraining the opening turning of said valve, said baiile being of such shape and location as to reduce the aspirating effect of said valve when partially open whereby to substantially equalize the dynamic effect of the air, flowing past the valve, on the surfaces of the valve on opposite sides of the valve axis and to permit said valve to be actuated as nearly as possible by the static pressures on it.

5. In a carburetor having a main inductionpassage, the combination of a fuel-chamber, means to feed fuel into said chamber, means to deliver fuel from said chamber into said induction-passage, a fuel-valve in said delivery means, an unbalanced air-admission valve for said passage mounted to turn about an off-center axis, the larger of the two sections of said valve at one side of said axis being curved outwardly to increase the opening efiect of the atmosphere on the valve, the smaller of the two sections of said valve at the opposite side of said axis being curved inwardly to reduce the aspirating effect of the valve when it is partially open, a baflie in said passage inwardly from and substantially in register with said smaller section of said air-admission valve at one side of said axis, said bafiie being of such shape and location as to reduce the aspirating effect of said valve when partially open whereby to substantially equalize the dynamic effect of the air, flowing past the valve, on the surfaces of the valve on opposite sides of the valve axis and to permit said valve to be actuated as nearly as possible by the static pressures on it, means restraining the opening turning of said valve, and means connecting said air-admission and fuel valves whereby they open and close conjointly.

.6. In 'a carburetor having a venturi-equipped main induction-passage, the combination of a fuel-chamber, means to convey fuel into said chamber, an automatically-acting air-admission valve for said induction-passage, means to restrain the opening action .of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to the interior of said fuelchamber above the liquid-level therein to draw fuel. into said chamber through said conveying means, means connecting said air-admission and fuel valves whereby they open and close conjointly, and means actuated coincidentally with the movements of said air-admission valve to bleed air into said fuel-chamber in predetermined quantity varying with the position of said air-admission valve to maintain a suitable fuel-. feeding head.

7. In a carburetor having a venturi-equipped main induction passage, the combination of. a fuel-chamber, means to convey fuel into said chamber, an automatically-acting air-admission valve for said induction-passage, means to restrain the opening action of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, a stem with varying cross-sectional area for said valve cooperating with a port and adapted to bleed air into said fuel-chamber to maintain a suitable fuel-feeding head, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to the interior of said fuel-chamber above the liquidlevel therein to draw fuel into said chamber I through said conveying means, and means connecting said air-admission valve and the stem 0 fsaid fuel-valve whereby the two valves open and close conjointly.

8. In a carburetor having a main inductionpassage, the combination of a fuel- -'chamber, means to convey fuel into said chamber, a float in said chamber, an air-admission valve for said induction-passage, means to restrain the opening action of said valve, a conduit for delivery of fuel from said chamber, means to increase the suction of said induction-passage and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply suc-. tion to the interior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, and

means to apply the weight of said float more I means to restrain the opening action of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, means connecting said air-admission and fuel valves whereby they open and close conjointly, means to increase the suction of said venturi and to withdraw fuel bysaid increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to theinterior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, and means to employ the weight of said floatimore or less to oppose the opening of said air-admission valve as the fuel-level in said chamber lowers.

10. In a carburetor having a venturi-equipped main induction passage, the combination of a fuel-chamber, means to convey fuel into said chamber, a float in said chamber governing the admission of fuel into the chamber, an airadmission valve for said induction-passage, means to restrain the opening action of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, means connecting said air-admission and fuel valves whereby they open and close conjointly, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to the interior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, means to employ the weight of said float more or less to oppose the opening of said air-admission valve as the fuellevel in said chamber lowers, and means actuated coincidentally with the movements of said airadmission valve to bleed air into said fuelchamber to maintain a suitable fuel-feeding head.

11. In a carburetor having a venturi-equipped main induction-passage, the combination of a fuel-chamber, means to convey fuel into said chamber, a float in said chamber governing the admission of fuel into the chamber, an airadmission valve for said induction-passage, a weight restraining the opening action of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, means connecting said air-admission and fuel valves whereby they open and close conjointly, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to the interior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, and means to augment the action of said weight on said air-admission valve by imposing the weight of said float more or less on said valve as the fuel-level in said chamber varies.

12. In a carburetor having a venturi-equipped main induction-passage, the combination of a fuel-chamber, means to convey fuel into said chamber, a float in said chamber governing the admission of fuel into the chamber, an air-admission valve for said induction-passage, a weight in said chamber restraining the opening action of said valve and forming a dash-pot with a portion of said chamber to preclude fluttering of said valve, a conduit for the delivery of fuel from said chamber, a. fuel-valve in said conduit, means connecting said air-admission and fuel valves whereby they open and close conjointly, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said induction-passage, means to apply a lesser increased suction to the interior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, and means to impose the weight of said float more or less on said weight to increase the restraining action of the latter on the air-admission valve as the fuel-level in the chamber lowers.

13. The structure presented in claim 12 in combination with means actuated coincidentally with the movements of said air-admission valve to bleed air into said fuel-chamber to maintain a suitable fuel-feeding head.

14. In a carburetor having a venturi-equipped main induction-passage, the combination of a fuel-chamber, means to convey fuel into said chamber and to limit its admission into the chamber, an automatically-acting air-admission valve for said induction-passage, means to restrain the opening action of said valve, a conduit for the delivery of fuel from said chamber, a fuel-valve in said conduit, means connecting said air-admission and fuel valves whereby they open and close conjointly, means to increase the suction of said venturi and to withdraw fuel by said increased suction from said chamber through said conduit and to deliver it into said inductionpassage, means to apply a lesser increased suction to the interior of said fuel-chamber above the liquid-level therein to draw fuel into said chamber through said conveying means, and thermostatically-controlled means to bleed air into said fuelchamber to vary the fuel-feeding head, said thermostatically-controlled means comprising a passage connecting the interior of said fuel-chamber to the outer air, and a valve controlling said passage and having a stem frictionally slidably held in a bearing in the carburetor and having a coefficient of expansion different from that of the carburetor body.

15. In a carburetor having a main Venturiequipped induction-passage with means to admit air thereto, a second suction-increasing venturi connected to said first venturi, a primary means to supply fuel to said induction-passage, a throttle-valve, a fuel-well, a conduit connecting with said second venturi and with said fuelwell, a passage connecting the upper portion of said fuel-well to said second venturi at a point of less suction than the conduit connection therewith, and means operative in conjunction with the opening of said throttle-valve to force supplemental fuel through said conduit into said second venturi, induction-passage, and fuel-well, the fuel thus pumped into said well subsequently flowing into said second venturi through said conduit after the action of said forcing means has ceased to prolong the mixture enrichment.

16. In a carburetor having a main Venturiequipped induction-passage, the combination of a fuel-chamber, means to admit fuel into said chamber, means to increase the venturi-developed suction and to feed fuel from said chamber by said increased suction into said inductionpassage, means to increase the Venturi-developed suction in lesser degree and to apply said lesser increased suction to the interior of said chamher to lift fuel into said chamber through said fuel-admission means, an air-admission valve for said induction-passage, means restraining the opening of said air-admission valve, a fuelvalve controlling said delivery of fuel from said chamber into said induction-passage, means controlled by said air-admission valve governing the action of said fuel-valve, means actuated by the movements of said air-admission valve adapted to bleed air into said chamber to vary the fuel-feeding head, a supplemental means to bleed air into said chamber for the same purpose, and a valve controlling the action of said supplemental means.

17. In a carburetor having a main Venturiequipped induction-passage, the combination of a fuel-chamber, means to admit fuel into said chamber, means to increase the Venturi-developed suction and to feed fuel from said cham- 20 her by said increased suction into said induction-passage, means to increase the Venturideveloped suction in lesser degree and to apply said lesser increased suction to the interior of;

said chamber to lift fuel into said chamber through said fuel-admission means, an air-admission valve for said induction-passage, means restraining the opening of said air-admission valve, a fuel-valve controlling said delivery of fuel from said chamber into said inductionpassage, meanscontrolled by said air-admission valve governing the action of said fuel-valve, a supplemental passage for delivery of fuel from said chamber for the same purpose, and valveinduction-passage, means actuated by the movements of said air-admission valveto bleed air into said chamber to vary the fuel-feeding head, a supplemental means to bleed, air into said chamber for the same purpose, and a valvemeans controlling said supplemental fuel-passage and said supplemental air-bleeding means.

TORBJORN LDIGA.

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