US1805763A - Carburetor - Google Patents

Description

May 19, 1931. R ENSlGN 1,805,753 VCARBURETOR ,Fi led June 22, 1926 Patented May 19, 1931 UNITED STATES PATENT orrlcn ROY F. ENSIGN, OF SOUTH PASADENA, CALIFORNIA, ASSIGNOR TO ENSIGN CARBURETOR (30., LTD, OF HUNTINGTON PARK, CALIFORNIA, A CORPORATION OF CALIFORNIA omunn'ron Application filed June 22,

The present invention has to do with carburetors of that general class used for .forming a combustible mixture for internal combustion engines; although, as will be readily understood, the invention is not necessarily limited to that particular use. 1

I may say preliminarily there are two ma]or objects of the invention which may be stated as follows: to provide a means and arrangement whereby the mixture, especially at light loads, is kept substantially unvarying in proportion when the carburetor is inclined in any direction from its normal position; and at the same time to provide means for modifying the mixture proportion at light loads, relative to the mixture roportion at heavy loads 1n.

order to reduce uel consumption.

It has been more or less a common-practice in carburetors to take off the fuel from the float chamber at ornear the center of the level controlling float, or at or under that point of the fuel surface which does not change its level when the carburetor is tipped. One object of the present invention is to provide new means and arrangements whereby the variation of fuel feed by tip ing is obviated but without the necessity of taking the fuel from the fuel chamber at any particular point.

At the same time, it is an object, in the same design and arrangement, to provide for modifying the fuel feed throughout the load range so as to keep the mixture proportions economical.

With these preliminary ideas in view, the invention itself, together with further objects and corresponding accomplishments, will be best understood from, the following detailed description of a preferred specific and illustrative form embodying the invention, reference for this purpose being had to the accomanvin drawin s in which Fig. 1 is a diagrammatic representation in section of my improved form of carburetor;

Fig. 2 is a similar view showing the carburetor somewhat tipped in one direction;

Fig. 3 is a similar view showing tipping in an opposite direction.

It will be understood that the illustrations herewith are merely diagrammatic and are not intended to represent the actual mechan- 1926. Serial No. 117,671.

ical structure of my improved carburetor, as the invention does not reside in mechanical structure, but only in the relative functional arrangements of the operating parts as hereinafter described and claimed. Consequently,

the-accompanying drawings and the following description will be taken only as typical and not as a limitation of my invention in any specific details.

- In the drawings-'- An air intake 10 is 'shown leading to mixture passa e 11 which is in the form of a Venturi tu and the upper part of the mixture passage has the controlling throttle 12 below the mixture outlet 13 to which suction is applied by the engine in the well known A fuel orifice 18 takes fuel at any point under liquid level L, the only restriction on the positlon of that fuel orifice being that it shall be low enou h to be always under the fuel level when t e carburetor is tipped to I the maximumangle at which it is designated to operate. This orifice 18 supplies fuel to fuel passage. 19 and thus to fuel nozzle 20 discharging into mixture passage 11. Fuel passage 19 may preferably be of such arrangement and conformation as shown in the drawings, having an upwardly rising leg,

and then having a part 19a which extends diagonally downwardly, the fuel passage thus defining a lip 22 which is the highest point to orover which the fuel is raised to reach nozzle 20. Y

An orifice 21 supplies air to passage 19- 19a from the air passage 17, orifice 21 being located near lip 22 of passage 19. Although, in the design here shown, lip 22 defines the point to which liquid fuel is raised from the float chamber the entry of air, mixing with the fuel, at 21, may also be said to define the point to which the fuel is'ra'ised by suction,

orifice 21 being close to lip' 22. Thus, either a lip (any high point in the fuel passage) or an air admitting orifice, may define that point to which fuel is lifted.

be exactly under lip 22.

The lower discharge end 17a of air passage 17' is here shown approximately under lip 22; not necessarily'directly under it, but

it is better to have 17 a: as closely directly in vertical alignment with lip 22 as is, practical in the'actual working design of the carburetor. In the drawing the center of discharge 17a is purposely shown somewhat removed from being directly under lip 22in order to illustrate-the fact that it need not .A suction passage 24 connects into outlet 13 at a point above throttle 12, (or, more properly speaking, above the throttle whenair flowing through the air intake and mixchamber,

ture passage draws fuel from the fuel supply chamber through orifice 18, the fuel being lifted to lip 22 and drawn through 1% in admixture with air drawn through orifice 21. Suction passage 24 causes a sub-atmospheric pressure to be applied in chamber 14, and this sub'atmospheric pressure causes air to flow through 26 and passage 17b-and 17 and to discharge under the fuel at point 17 a,

the liquid level in passage 17' being depressed t'o'thepoint 17a. The amount of this discharge is controlled by'the relation between the orifices at 25 and 26, because the relation of those orifices controls the degree of subatmospheric pressure applied to the fuel In actual practice orifice 25 is made as small as, practicable (about .030 inches diameter.) and thesize of orifice 26 is properly gauged to maintain the desired sub-atmospheric pressure in chamber 14.

When the throttle is closed or nearly closed, the pressure in chamber 14 will be substan tially just low enough thatair will continuously discharge at the point 17 a and bubble up through the fuel in chamber 14, without causing any considerable resistance inthe passages l7 and 17 b or at the discharge point 17a. Since there is substantially no resist- V 'ance in passages 17 and 17b, the pressure at the point 17a will be substantially atmospheric orsubstantially the, same as the pressure in air intake. 10. As long as this prestenures sure remains the same at fixed point17a, fuel must be lifted the equivalent of the distance between point 17a and point 22, in order to reach nozzle 20. In order to explain this, let it first'be considered, that if atmospheric passage 17 were not present and there were full atmospheric pressure in chamber 14, then suction at nozzle 20 would have to lift the fuel from level L to point 22. With sub-atmosphere applied to fuel chamber 14, it is apparent that suction at nozzle 20 must lift the fuel through what I may term the equivalent of a greater height; and that increase in height through which the fuel must be lifted is measured exactly by the distance the fuel level is depressed in passage 17, due to the degree of sub-atmospheric pressure present in chamber 14. In I other words, the total height to which the fuel is lifted is at all times measured by the vertical distance between 22 and level L, plus the vertical depression of fuel in 17 below the. level L. Thus, when the sub-atmosphere in chamber 14 is suflicient to depress the fuel level in passage 17 to the point 17 a, then suction at nozzle 20 must lift the tical distance between point 17a and point 22.

The fact that when the fuel level is depressed to the point 17a the air begins to bubble through the fuel into the upper part of the fuel chamber, automatically places a limit upon the degree to which the fuel level can be depressed in passage 17a; and, as I have said before, the proportions and arrangements are such that, at low speed'and loadidling or near idling operation of the enginethe fuellevel in 17 will be at the point 170:. V7 hen the throttle is opened, pres sure in outlet 13 above the throttle is of course very much increased, and the pressure in fuel chamber 14 approaches atmospheric pressure Fuel then rises correspondingly in passage 17, decreasing the efiective height throughwhich suction at 20 must liftthe fuel, and thus slightly increasing the relative richness of the mixture. 17 has risen high enough to submerge small passage 27 fuel then flows-through that passage into fuel passage 19, thus effectively increasing the supply of fuel to the fuel passage. Previous to the riseof the fuel level above 27, some air has been passing through 27 into the fuel being drawn up through fuel passage 19, and the cutting off of this air supply and substitution of a-fiow of fuel through 27 relatively enriches the mixture. I say that "these'actions relatively enrich the mixture because that relative enrichment is in fact a mere modification of what the relati ee mixtures would otherwise be. Withou these arrangements the mixture at high load would be too thin, or, putting the matter the other way, the mixture at low loads would be relatively too rich for economical operation; and

fuel through a height equivalent to the vera When the fuel in the arrangements here described modify v those mixtures in the general manner well known in economizers.

As long as the fuel level in 17 is below air bleed 27, variations in suction applied 'to nozzle 20 will cause some variation in the amount of air taken through bleed 27. Thus, as the suction increases, due either to increased engine speed or throttle opening, the air taken in at 27 will somewhat increase,

due to increased suction at 27. But the such purposes, it will of course be well understood that the proportions of the various parts are necessarily modified to suit differentengines; but as a typical instance I may say that orifice 25 may be .030 inches in diameter, orifice 26 may be .070 inchesin diameter; orifice 21 .050 inches in diameter; orifice 27 .030 inches in diameter, and orifice 18 .050 inches in diameter. For the purpose of operating in normal position it willbe readily understood that it is not necessary in the least for discharge point 17a of passage 17 to be-in any specified relation to lip 22, over which the fuel is lifted. For purposes of operation in a tipped position, it will be understood from what is described herein after that discharge point 17a should be nearly in vertical alignment with lip 22.

Suppose now the carburetor 'to be operating in such a position as indicated in Fig. 2, tipped so that the fuel level L1 in chamber 14 is lowered in passage 17. From a consideration of Fig. 2 it will be seen that when operating at low speeds and loads, with air discharging at 17a, the suction at nozzle 20 must lift the fuel through a'height equivalent to the vertical distance between 17a and 22. In other words, because discharge point 17a limits in all positions the amount of fuel depression in 17, and therefore limits the degree of sub-atmosphere that can be applied to chamber 14, even in this tipped position,.

under idling operation, the suction of nozzle 20 can only be called upon to lift the fuelthrough the equivalent of the vertical distance between 17a and 22. Now suppose the throttle to beopened, increasing the pressure in chamber 14 and thus allowing the fuel, to rise in 17. As soon as orifice 27 is covered, then additional fuel will pass through that orificeas before. The rise of fuel in 17 when the throttle is opened, al-

though it decreases the vertical'distance by which suction at nozzle 20 must liftthe fuel,

has a practicallynegligible effect on the mixture except by the fact of feeding fuel through 27. At open throttle,.the suction on nozzle 20 is so strong that small changes in the fuel lift make no substantialchange in the mixture. At closed or nearly closedthrottle the suction is so small that slight variation in the fuel lift will materially change the mixture; and my arrangement, as above described, keeps the fuellift unchangeable at closed-or nearly closed throttle in spite of changes in the fuel level.

If, as in Fig. 3, thecarburetor is tipped in the opposite direction, when operating at closed or nearly closed throttle, the liquid level in 17 is again depressed to 17a and, as before, the height to which suction at nozzle 20 must lift the fuel is the equivalent of the distance between points 17a and 22; and as the throttle is opened and pressure in chamber 14% is increased, the fuel will rise commensunately and begin to pass fuel through orifice 27 as before. The proportions and di-' mensions of the parts being made such that air will always pass the point 17a at low speed and load operation no matter how the carburetor is tipped, it will readily be seen that no matter in what position the fuel level L may be, the distancethroughwhich the fuel must be .raised by suction of nozzle 20 is always the equivalent of the vertical distance between 17a and 22. That this is so will be seen by considering the three figures. In

Fig. 1 the level is at L, and the amount of depression in 17 is the vertical distance between level L and point 17a. ,In Fig. 2 the level is at L close to point 17a, and lower with relation to point 22; but the depression in 17 between level L and discharge point 17 a is correspondingly less, so that what I call the equivalent height throughwhich suction must raise fuel in passage19 remains substantially the same as before. And the same is true in the instance shown in Fig. 3 where level L2 has risen'with relation to point 17a, but the depression of liquid in 17 to reach point-17a is also correspondingly increased. It will .now be understood why discharge point 17a should be nearly under lip 22. In such relative positions of 22 and 17a, tipping of the carburetor through small angles makes very little change in the vertical distance between 17 a and 22; so little change that the action of the carburetor at idling or nearidling is not affected by tipping. On the other hand, if 17a were located at a considerable horizontal distance from 22, then tipping of the carburetor would make a correspondingly larger change in the vertical distance between 17 and 22;

And further from all'that l have now said, i

in aplane at right angles to the plane of the several figures or in any other plane, In the drawings, discharge opening 170 is shown in the same vertical plane (the plane of the figures) with lip 22. Qonsequently, tipping of the carbiu'etor out of the plane of the figures, as well as tipping as illustrated in the figures, or tipping out of any normal vertical plane diagonal to the plane of the figures or plane at right angles thereto, will not affect operation of the carburetor.

The changes in the fuel level that l have described are changes due to tipping of the carburetor; but it will now be readily understood that my arrangement will compensate equally well for fuel level changes due to any other cause For instance, the fuel level in 1% may vary due to slackness of float and valve action therein, or due to the valve not seating properly, or many other causes known to the art, and still my carburetor will function normally. In truth, a carburetor such as 1 here describe does not need, in the strict sense of the term, a constant level fuel chamber in which fuel level is accurately regulated; although of course in any preferred construction the carburetor, as actually made, may always be provided with such constant level maintaining devices.

The foregoing description has assumed that passage 17 has atmospheric pressure in it; and this may be true. However, by the provision of tube 1??) connecting with intake 10, compensation is automatically provided-for any variation from the normal atmospheric pressure thatmay occur in intake 10 due to the placement of any automatic valves or air cleaners or other devices on the atmospheric intake of the carburetor. Such devices modify the pressures throughout the carburetor, and therefore of course would modify the mixtures. l he provision of tube 176 connectin with passage 1'7 compensates for all such modifications of pressures.

' I rlaim:

1. ln a carburetor having mixture passage to which suction is applied, a fuel chamber, and walls defining a fuel passage leading from the fuel chamber into the mixture passage, said fuel passage having therein at a dcfinitclevel an overflow edge to which fuel. must be lifted to the discharged into the mixture passage; the combination of means to feed air into theliquid in the fuel chamber outside of said walls defining said fuel passage, and below the normal fuel level at a point vertically below said overflow edge in the fuel passage, and means to apply to the surface of the fuel in the fuel chamber a pressure lower than that in said air feeding means.

Quill a carlnu'etor having a nurture pasreserves definite level an overflow edge to which fuel must be lifted to be discharged into the mixture passage; the combination of means to feed. air at substantially atmospheric pressure into the liquid in the fuel chamber outside of said walls defining said fuel passage, and at a point beneath the fuel level and vertically below said overflow edge in the fuel passage, and means to apply a subatmospheric pressure to the fuel surface in the fuel chamber.

8. In a carburetor having a mixture passage to which suction is. applied, a fuel chamber, and walls defining a fuel passage leading from the fuel chamber into the mixture passage, said fuel passage having therein at a definite level an overflow edge to which fuel must be lifted to be discharged into the mixture passage; the combination of means for applying air pressure from the air intake of the mixture passage to' a point in the liquid body in the fuel chamber beneath the fuel level and outside of said walls defining said fuel passage, and vertically below said overflow edge in the fuel passage, and means to apply to the fuel surface in the fuel chamber a pressure less than that of said air intake.

i. In a carburetor having a mixture passage to which suction is applied, a fuel chamber, and walls defining a fuel passage leading from the fuel chamber into the mixture passage, said fuel passage having therein at a definite level .an overflow edge to which fuel must be lifted to be discharged into the mixture passage; the combination of an air passage open at its outer end outside the fuel chamber to the atmosphere and extending downwardly beneath the fuel level in the fuel chamber outside of said walls defining said fuel passage and having its lower end opening into the liquid fuel at a point vertically below said overflow edge in the fuel passage, and means to apply a sub-atmospheric pressure to the surface of the fuel u in the fuel chamber. a

5. In a carburetor having a mixture passage to which suction is applied a fuel cham her, and a fuel passage leading from the fuel chamber into the mixture passage, said fuel passage having therein. at a definite level an overflow edge to which fuel must be lifted to vbe discharged into the mixture passage; the

combination of an air passage open at its outer end outside the fuel chamber to the atmosphere and extending downwardly beneath the fuel level in the fuel chamber and having an open lower end located at a point vertically below said overflow edge in the fuel passage, means to apply a sub-atmospheric pressure to the surface ofthe fuel in the fuel chamber, an auxiliary fuel passage leading between that portion of the air passage within the chamber and the first mentioned fuel passage and located at a point above the lower end of said air pasc sage but below the normal fuel level in said fuel passage. 4

6. In a carburetor having an air intake,'a mixture passage, a controlling throttle, and an'outlet above the throttle to which outlet suction is applied, a fuel chamber, and a fuel passage leading from the fuel chamber and discharging into the mixture passage and having therein at a definite level an overflow edge to which fuel must be lifted in order to reach the mixture passage; the combination of an air passage presenting its outer end to the air in said air intake, and extending downwardly in the fuel chamber to a point beneath the normal fuel level therein, and having an open discharge end. at apoint vertically'below said overflow edge in the fuel passage, and means to apply suction 20 from said outlet to the surface of the fuel in the fuel chamber.

7. In a carburetof'havin an air'intake, a mixture passage, a controlling throttle, and an outlet above the throttle to which outlet suction is applied, a fuel chamber, and a fuel passage leading from the fuel chamber and discharging into the mixture passage and having therein at a definite level an overflow edge to which fuel mustbe lifted inorder to reach the mixture passage the combination of an air passage presenting its outer end to the air in said air intake, and extending downwardly in the fuel chamber to a point beneath the normal fuel level therein, and having an open discharge end at a point vertica'lly below said overflow edge in the fuel' passage, and means to apply suction from said outlet to the surface of the fuel in the fuel chamber, there being an air bleed from said air passage into the upper part of the fuel chamber.

8. In a carburetor having an air intake, a, mixture passage, a controlling throttle, and an outlet above the throttle to which outlet suction is' applied, a fuel chamber, and a fuel passage leading from the fuel chamber and discharging into the'mixture passage and having therein at adefinite level an over flow edge to' which fuel must be lifted in order to reach the mixture passage; the combination of an air passage presenting its outer end to the air in said air intake, and extending downwardly in the fuel chamber to". apomt: beneath the normal fuellevel "a point vertically below said overflow edge inthe fuel passage, meansto apply suction from said outlet to the surface of the fuel in thefuel chamber, and an auxiliary fuel passage leading into the first mentioned fuel passage from said air passage-at a point above the lower end but below the normal fuel level therein.

9.1a a carburetor having-an air intake,

a mixture passage,.a controllmg throttle, and

an outlet above the throttle to which outlet suction is applied, a fuel chamber, and a fuel passage leading from the fuel chamber and discharging into the mixture passage and having therein at a definite level an overflow edge to which fuel must be lifted in order to reach the mixture passage; the combination of an air passage presenting its outer end to the air in said air intake, and extending downwardly in the fuel chamber to aa7 point beneath the normal fuel level therein, and havin an open discharge end at a point vertically-bclowsaid overflow edge in the fuel passage, means to apply suction from said outlet to the surface of the fuel in the fuel chamber, there being an air bleed from said air passage into the upper part of the fuel chamber,'and an auxiliary fuel passage leading into the first mentioned fuel passage from said-air passage at a point above the lower end but below the normal fuel leveltherein. a I

y In witness thatl claim the foregoing I have hereunto subscribed my name this 13th day of June, 1926. -V 90 ROY F. ENSIGN.'

therein, and having an open discharge end at. p

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