US1116023A - Carbureter. - Google Patents

Description

M. O. CRAWFORD.

OARBURETER.

APPLICATION FILE-D APR. 13, 1914.

Patented Nov. 3, 1914.

ATTORNE Y.

ll-llll 70 Mara-HEW o. omwronn, or nnrnorr, MICHIGAN.

CABIBURETER.

Specification of Letters Patent.

Patented Nov. 3, 191.4.

, Application filed April s, 191;. Serial -1wo.'aa1,43s.

To all whom it may concern:

Be it known that I, Ma'rrrmw O. CRAW- 1 FORD, a citizen of the United States, residing, at Detroit, county of Wayne, State of Michn. gan, have invented'a certain new and useful- Improvement in Carbureters, and declare the following to be a full, clear, and exact description of the same, suchas will enable others skilled in the art towhich it pertains to make .anduse the same, reference being had to the accompanying drawings, which form a partof this specification.

This invention relates to carburetors, and

an object thereof is a carbureterof an improved type and simple formfor use. with Internal combustion engines.

The primary object of my invention is a carburetor in which the constituent proportions of the gaseous mixture are constant'at all speeds of the -11101301311131?1S, directly pro-' portional to the the motor. p

A further object. resides in'the means whereby the liquid fuel -is divided and quantity .of ant drawn into broken up prior to its entrance into the mix- 1 ing chamber.

A furtherobjectresides in the means employed whereby a rich mixture ispio vided when first starting the engine. y

In the ordinary carbureterthe fuel feed is not directly proportional to the quantity of air'drawn into the engine, but is excessive at high speed and insufficient at'low speed by reason of the variationsin' the degrees of vacuum produced at the various speeds. To obviate this, the fuel. passage is sometimes restricted in area as the throttle is opened,

a and increased with the closing of the throttle, or additional air is mixed with the charge' through operation of spring controlled valves or the like.

In the invention herein disclosed the desired 'm-ixture regulation is automatically attained through obtaining the fuel supply,

from two sources, one of which remains constant at all speeds of the motor, and the other of which varies therewith, but which is manually regulatable so that the flow may be increased, or diminished as maybe found necessary to produce the best result operation. Both of these sources of sup 1y are subject to atmospheric pressure and t ecombined feed from the two sources produces a uniform mixture at all motor speeds as is hereinafter shown. v

It is also an object of this invention to 1ncorporateihe above objects in a structure of slmple form and small number of parts.

' These and further objects and novelties of the invention are hereinafter more fully described and claimed and shown in the accompanying drawings in which F igure 1 1s a plan view of a carbureter em bod mg my invention. Fig. 2 is an end view thereof taken from the intake end. Fig. 8 is a vertical section on line w-w of Fig. 1. Fig. 4 is a section taken on line a, b, c, d, of Fig. 1. Fig. 5 is a section on line a, e, f, at, of Fig. 1. Fig. 6 is a vertical section on line ez of Fig. 1. Fig. 7 is a diagram showing in a general way the ratio of gasolene to air from the two sources of supply.

' Similar characters refer to similar parts throughout the drawings and specification. The device consists of a main conduit 1, and a secondary conduit 2, both having the form of aVenturi tube, the secondary condu'it-Q- entering the main conduit-tutor near the. point of greatest restriction and is thus subject to the variations ixjiressurein the main conduit. 5

As may be more clearly seen in Figs. 3, 4: and 5, the secondary Nenturi .tube 2 has a cylindrical outer surface and is provided with a flan e 3 on the upper end. The tube 2 is inserte in an aperture in the upper wall of the main conduit, tightly fitting therein, the flange limiting the extent of its insertion into the main tube. The secondary tube has a restricted portion 4,.a'1i'dat or near the point of greatest restriction, upon the outer surface of the tube, is formed a groove or channel 5. Apertures 6 are formed in the bottom of said groove leading into the interior of the tube at such restricted point.

Preferably formed integrally with the main conduit 1 is a float chamber 7 in which is a float 8 of any approved form. The float is o eratively connected to the pivoted lever 9 w ich has a forked arm 10 engaging in a groove in the head of the stem 11 of the fuel valve 12. The'stem ridesin and is guided by an aperture inthe lug 13 formed atone side of the float chamber. The fuel enters the float chamber 7 through the conduit 14 controlled by the fuel valve and the operabottom. The well 16 is open to the'full extent being substantially uniform in diameter throughout its length, while the fuel well 15 at the bottom thereef is restricted being provided with a plugQ-17 having a calibrated passageway 18 restricting the flow of fuel thereinto from the-fuel chamber asis .hereinafter shown. A certain diameter of the passageway 18 will produce the best result with agiven engine and, by forming thepassageway in an insertible plug, tests may be made with passageways of various diameters and the one that gives the-most effective result determined. Thereafter carbureters made for such particular sizeand type of em gine may dispense with: the insertible plug, thewell being formed. With-a bottnm andthe passageway formed in the solid wall practically at the same point, as in the plug shown in Fig. 4. Leading from near the bot tom of each of these wells 15 and 1-6is a passageway 19 and 20 respectively, each' of which terminates in the aperturefor the secondary conduit 2 at the point registering.

with the groove 5 in said secondary conduit. The normal level of fluid in thesewelle and the fuel chamber is shown bv dotted linesyy in Figs. 1 and 5. The well 16 is thread ed at the upper end thereof to receive the threadedportion 21 of the regulating screw 22 by means of which the cross-sectional area of the passageway 20 may be varied. This screw passes through an aperture in the cover plate 23 for the fuel chamber registering with the well 16. The upper end of the well 15' is closed by the cover plate,'but the well is open to the float chamber above the fluidlevelthrough the aperture 24 in the wall thereof. As shown in Fig. 6, the cover plate is apertured at 26- so that the fuel in the fuel chamber 7 is also subject to atmospheric pressure. The head of the fuel valve may be-provided with a slot to receive a screw-driver blade or like instrumentto r0 tate the valve and dislodge foreign material or 'rind it on its seat.

The flow of air through the conduit 1 is controlled by the butterfly valve 27 operated in any convenient'manner asby a lever 28 having an adjusting screw 29 limiting the extent to which it may be closed. A small conduit or passageway 30is also formed in the upper wall of the main conduit,-'as shown in Figs. 1 and 3, leading into the conduit at a point 31 just forward of the upper edge of the butterfly valve when in its closed position in which there is a small passageway for air between the-uppenedge of the valve and the Wall of the conduit. Air, in rushing past the, point 31,- draws the fuel from the conduit 30 which leads into the aperture for the secondary Venturi tube 2 in registration with the channel 5 in said tube.

As maybe seen in Fig 4,. the well 15',

fuel supply, is-nearly full of fuel when the engine is at rest, While the amount of fuel which may enter-thewell or chamber 16 and the connected conduit 20 is considerably less in volume.

In starting the engine with the throttle slightly open as shown in Fig. 3, air is drawn past the'outlet 31 of the passageway30, at a high rate of speed, and as the channel 30 is connected with the channel 5 surrounding the small secondary tube 2, to which both thewells 15 and 16 are connected, fuel from boththese wells 'will be drawninto the maintube which results in a very rich mixture desirable at the time of starting the engine. The fuel in the well 15 will be practically entirely ,removed and an amount drawn through the well 16 and the corresponding passageway, as may be determined'by the aspiratin'g effect of the-air passing the point 31. As the valve 27 is opened to increasingly greater extents the aspirating effect at the point 31- gradually ceases and such effect at the restricted point of the main conduit 1 increased, being the highest atthe time the valve is fully open: or nearly so. This produces a suction in the tube 2,.the greatest as- --pirati-ng effect of which is at the point of greatest restriction, which point isin communication with the channels 19 and 20, and the corresponding wells 15 and 16. As this aspirating effect incrca'sesthe' flow of fluid through the conduit 20 increases to-a greater extent. The How to the channel 5 from the well 15 is constant after the well has first been. emptied, as the flow is produced solely by the weight of liquid in the fuel chamber and restricted by the calibrated passageway 18. This well, being open to atmosphere through the fuel chamber is not altered in rate of How by the aspirating effect at'the discharge end 32 of the tube 2. The well 15 therefore, provides what may be termed a compensating fuel supply. That is, ,the quantity of fuel delivered into the main vaporizing tube 1, is the amount delivered from the well 15 and conduit 19 combined with that from the well 16 and conduit 20. The quantity delivered through the conduit; 20 from the well 16 increases in percentage to the quantity of air, as theispeed of the engine increases, and that flowing from the well 15 thnough the conduit 919 decreases in similar ratio to the quantity of air drawn into the engine as'it can flow into the well 15 only ate single rate of speed, .and although the flow be. constant its percentage as compared with the volume of air in a single unit of time increases as the volume of air increases. Therefore, the combined supply from these two sources is exactly in proportion to the quantity of air drawn in. The result of the use of the two sources of supply under the conditions stated may be graphically shown bythe diagramFig. 7,

with any particular engine with which the carburetor may be used.

' By use of the small secondary Venturi tube 2 in supplying fuel to the main air conduit, such devices as jets and nozzles may be dispensed with, and mechanical adjustment of such parts in an attempt to maintain the proper proportion of the mixture, and other faults incident to their use avoided. A jet, as the word indicates, delivers fuel into the air conduit in a stream, and so far as I am aware, the stream always flows in the same direction as the air pass-- ing through the conduit and a uniform mix- .ture of the air and fuel is practically impossible, the fuel in most instances not being completely vaporized until it has entered the intake manifold of the engine. The fuel feed herein disclosed is not a jet, as the fuel does not enter the small Venturi tube 2 in a stream but the action is similar to that of the small perfume atomizers commonly in' use in which a stream of air passes directly over the mouth of a. supply channel or oi'ifice in a direction at an angle to the direction of the flow of the air which thoroughly breaks it up into a very fine spray. In the device shown more particularly in Fig. 3,

there are several apertures 6 through the wall of the Venturi tube 2 leading into thechannel 5, which is in communication with the sources of fuel supply. Air in vpassing across the face of these apertures produces a very fine spray which passes out of the Venturi tube 2 at the point 32, and is there mixed with air flowing through the conduit 1, producing a uniform gaseous mixture.

The only part to be manipulated is the throttle valve 27, all the other parts operating automatically without the necessity ofthought upon the part of the operator, and by arranging the various parts in the general manner shown by the drawing, expensive machine work is entirely dispensed with, -as no particularly close fits are required, except possibly in the fitting of the small secondary tube .to prevent leakage along the surface thereof. The device may be cheaply, made and assembled in proper relation without great care being exercised in the adjustment of parts relative one to the other, the whole resulting in a very elficient and inexpensive device.

In what'is known as a 5} carburetertoperating a. 2%214 motor, I have found the following sizes of conduits to produce a very efficient result: The main conduit 1 is one inch in diameter, while the restricted portion thereof is 5 of an inch in diameter. The diameter of the restricted portion of a secondary conduit 2 is of an inch in diam eter, and the fuel conduit 5 thereabout "is of an inch'wide by of an inch deep with four apertures 6 leading thereinto each of an inch in diameter. The conduit 30 is j g of an inch in diameter, and the aperture 31 leading'thereinto is made by a No. 56 drill. The well 15 is of an inch in diameter and the well 16 is of an inch in diameter, and each of the conduits 19 and 20 are of an inch in diameter. The apermegs leading into the well 15 in this instance is made by a No. SS-drill. The above dimensions are given to indicate the relative sizes of the parts mentioned as found eflicient with a certain motor, and it is to be understood that these dimensions may be varied to suit various conditions of operation, sizeof the motor, size of carbureter, etc.

In starting the engine with the throttle very nearly closed and the engine being cranked, the passage of air though the main conduit 1 draws oil from the wells 15 and 16 into the fuel passage 5. As this air passes by the aperture 31 the high suction occur ring at that point will draw the oil therethrough into the main conduit, and under this condition of operation I have found very little oil enters the main conduit through the secondary conduit at 32. Al-

' though high suction occurs at 31, the area of the aperture is so'small that such suction is not sufficient of itself to draw oil from the wells into the fuel conduit, such result being attained by the passage of the air through the main conduit past the point 32 of the secondary conduit.

lVit-h a half-open throttle the suction at 31 is decreased to a very great extent and the suction at 32 is increased by reason of a greater quantity of air passing thereby than occurs in starting condition. Practically all the fuel with the half-open throttle therefore enters the main conduit at and although some suction occurs at 31, but lit tle oil passes therethrough. As the oil in the well 15 sinks to the level of the bottom of the passage 19 air entering through apertures 26 and 24 will mingle with the oil at the base of the passage 19 and the emulsion will flow up 19 into the fuel conduit 5.

This condition exists whenever the suction through the passageway 19 is great enoughto take the oil faster than it may flow through the aperture 18 into the well.

At high speed, with a full open throttle, the vacuum at 32 is increased as is also the vacuum at 4, and while it is possible that this may induce a flow of air through the aperture 31- back through the conduit 30, and out at, aperture 6, the amount that may thus flow through the conduit 30 is so small as to be of no detriment to the operation of the carbureter. At high speed the air passing through the main conduit necessarily produces some suction at 31 but the suction at as 1 the 4 may also be much higher. Howeve there are several apertures 6 subject influence of the vacuum at 4 and as with the passageways 19 and 20 as well as the passageway 30 are in communication with the said apertures and each similarly subjected to the influence of the vacuum, each passageway is not aflected to the same extent as Would be the case if only the passageway 30 was subject to such influence. The passage 30 being also subject to a partial vacuum at both ends, the flow, if any, to the fuel conduit 5 and apertures 6 through the passageway 30 is so slight as to be of no moment.

Having thus described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is 1. In a carbureter, an air conduit, a fuel conduit subject to the influence of air pass ing through the air conduit, a suction controlled fuel feed and a fuel feed giving a constant supply per unit oftimeboth said feeds discharging into said fuel conduit.

2. In a carbureter, an air conduit, and a fuel conduit discharging thereinto, said fuel conduit being provided with two sources of .fuel supply, one providing a supply vari able per unit of time, and one constant per unit of time. 7

3. In a carburetor, an air conduit, :1 secondary-air conduit leading thereinto, a fuel conduit in communication with said secondary conduit, a suction controlled fuel feed supply and a fuel feed constant per unit of time discharging into said fuel conduit.

l. In a carbureter, a. atomizer, a fuel conduit communicating therewith, a suction j stant level fuel: chamber, a fuel conduit subcontrolled fuel supply, and a fuel supply constant per unit of time both discharging into the fuel conduit.

5. In a carbureter, in combination with a fuel atomizer, a suction controlled fuel sup.- ply, and'a fuel supply constant per unit'of time, both discharging into the fuel inlet'of the atomizer.

6. In a, carlmireter, an air conduit, 2.

conduit subject to. the influence of airpass ing. through the airconduit and adapted to deliverfuel into the air conduit at an angle to the direction of the flow of air therethrough, a suction controlled fuel feed, and a fuel feed supply constant per of time, both discharging into the fuel conduit.

7. In a carbureter, an air conduita fuel conduit, ubject to the influence of air pass ing throh the air conduit, a suction consome mu feed and a fuel feed supply constant per unit of time, both discharging into the fuel conduit and both being subject to atmospheric pressure.

8. In a carbureter, an air conduit, a fuel conduit subject to the influence of air passing through the air conduit, a suction controlled fuel feed, and a fuel feed adapted to deliver a constant supply per unit of time, both said feeds discharging into the fuel conduit, and a constant level supply chamber for said feed.

9. In a carburetcr, an air conduit, a secondary air conduit leading thereinto, a fuel conduit subject'to the influence of airpassing through the secondary air conduit, a suction controlled fuel feed and a fuel feed adapted to give a constant supply per unit of time, both said feeds discharging into the fuel conduit.

10. In a carbureter, an airconduit having the form of a Venturi tube, a secondary air conduit of like form discharging thereinto substantially at the point of greatest variation in air pressure, a fuel conduit communicating with said secondary air conduit substantially at the point of greatest variation in air pressure, a fuel supply variable per unit of time, and a fuel supply constant per unit of'time both communicating with said fuel conduit.

11. In a carburetor, a throttle controlled air conduit having the form of a Venturi vinto said secondary conduit at the point of greatest variation in air pressure,' a suction controlled fuel supply, a fuel supply constant per; unit of time, both supplies being in commimicetion with the fuel conduit, and apas'sa-ge from said fuel condiut leading into the main air conduit in proximity tov the throttle.

12. In a carburetor, an air conduit, a conject to the influence of air passing through 'the air cond'uit, and two fuel supply wells in communication with the fue adapted to discharge into the fuel conduit,

chamber the flow to one of said wells being restricted and the flow from the other well being regulatable.

13. In a carbureter, a primary air conduit, a constant level fuel supply chamber formed integrally therewith, a secondary air conduit arranged to discharge into said primary air conduit, a fuel conduit subject to the influence of air passing through the secondary air conduit, and two fuel wells formed, in the wall between the fuel supply chamber and the primary airconduit each in communication with both the, fuel conduit andthe fuel supply chamber; the, flew to one of said wells being restricted and tle flow from the other well being regulata le.

14. In a carbureter, an air conduit, a constant level fuel supply chamber formed integrally therewith, a secondary air conduit arranged to discharge into the said primary air conduit, a fuel conduit leading into the secondary air conduit, and two fuel wells formed in the wall between the fuel supply chamber and the primary air conduit, each in communication with both the fuel conduit and the fuel supply chamber; the flow to one of said wells being restricted and the flow from the other well being regulatable; the well having the restricted flow being open to atmosphere through the fuel cham- 1 her.

15. In a carbureter, in combination, a primary air conduit having the form of a Venturi tube, a throttle in said conduit, a constant level fuel supply chamber formed integrally therewith, va seconda'ry'air conduit fuel supply wells formed in the wall.

between said fuel supply chamber and the primary air conduit, each in communication with both the fuel conduit and the fuel supply chamber; the flow to one of said wells being restricted and the flow from the other Well being regulatable, and a passage from the fuel conduit leading into the primary air conduit in proximity to the throttle.

In testimony whereof, I sign this specification in the presence of two witnesses.

MATTHEWV O. CRAWVFORD.

Witnesses:

RUBY L. Coon, CHARLES E. WISNER.

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