US1895470A

US1895470A - Carburetor

Info

Publication number: US1895470A
Application number: US442786A
Authority: US
Inventors: Mathieu Eugene
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-04-30
Filing date: 1930-04-09
Publication date: 1933-01-31
Anticipated expiration: 1950-01-31
Also published as: GB350134A; BE369218A; FR690566A

Description

Jan. 31, 1933.

E. `Myra-NEU CARBURETOR Filed April 9, 1930 4 Sheets-Sheet l l A, m

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CARBURETOR Filed April 9. 1930 4 SheebS-Sheet 2 .mm IT. QN M... eV l nm \E. 3. v. U vb E E. MATHIEU Jan. 31, 1933.

CARBURETOR Filed April 9, 1930 4 Sheets-Sheet 5 Eugne. MuJrhLeu INV-NYOR;

L n Attoruya E. MATHIEU CARBURETOR Jan. 31, 1933..

Filed April 9,- 1930 4 sheets-'sheet 4 Eugne.' Malrhieu aNvcN'raR;

' Attorney.

ramadan. 31, 1933 lUNITED STATES PATENT OFFICE cnnunnron Application med April 9, 1980, Serial No. 442,786, and ln France April 30, 1929.

The present invention relates -to carburetors ttorv internal combustion engines, and it has chiefly for its object to improve the atomizing of the liquid fuelby the air and to obtain a substantially constant proportion ofuel in the mixture at the dierent rates of suction of the engine.

'lo this end, an important feature of-the invention consists of animproved arrangement for the atomizing'of the so-called primary mixture, wherein the liquid fuel under pressure is sprayed at a point below the constant level in the form of a spread-out sheet or radial jets, into an annular conduit in which is circulated a thin cylindrical stream of primary air and which comprises a restricted part situated at the level-at which the fuel is sprayed out, whereby the primary air will be given a great speed at this point, the angle between the direction of the current of primary air of tubular form and saidsheet or jets of liquid uel being substantially 90 degrees.

consists in the provision of a device for correcting the composition of the fuel mixture at high speeds of the engine, and for atomizing the fuel for the correction, or correcting fuel, the arrangement being` such that the delivery oi liquid through the correctingoriices will be impeded to a greater degree according as the speed of the primary air is greater.

Another feature of the invention consists of a particular disposition of the parts of the nozzle, in order to assure a progressive suction as well as an atomizing of the reserve supply of liquid which collects in the recesses o or chambers surrounding the .nozzle during stoppage or slow-running periods, and which forms the reserve of liquid by which the speeding up of the engine'is facilitated. Further features of the invention will be -speciied in the following description, with reference to the accbmpany'ing drawings, which show, by way of example, various embodiments of the invention.

Fig. 1 is af partial vertical section of a carburetor o the verticaltype.

Another important object of the invention Figs. 2 to 7 are partial sections of atomizers according to different modifications.

Fig. 8 is a sectional view of anv atomizer showing a different arrangement.

Figs. 9 and lll-are diagrammatic sectional 55 views showing modifications of the atomzer.

Figs. 11 and 12 show respectively in vertical section and in plan vlew a device for the discharge of the primary mixture into l the engine suction conduit, in the case of a horizontal carburetor.

Figs. 13 and 14 are views similar to Figures 11 and 12, respectively, relating to a modification.

Fig. 15` Vshows an atomizer having several 65 elements arranged in series.

Figs'. lto 18 are sectional views of atomizers provided with correcting orifices. Fig. 19 shows a device for atomizing the reserve supply of fuel. Fig. 20 is a vertical sectioh of a horizontall l carburetor comprising a device for atoxn-s izing the reserve supply of fuel, and,

Figs. 21 and 22 relate to modified devices for atomizing the reserve supply. rlhe carburetor represented in lFigure 1 comprises a float chamber 1, at the lower part whereof opens a duct 2 formed in a boss 3, which projects into the suction'conduit 4 ont the engine and supports the atomizing de- 50 vice denoted generally by 5, and in which is eifected themixture of the liquid fuel en- Y tering through duct 2 and the primary air entering through a conduit 6. The primary mixture proceedsrom said atomizing dna-'N85 vice through a nozzle 7 into a Venturi tube 8, mounted in the suction conduit, beyond which is a throttle 9 or other thrttling means. Y

Y The carburetor is further provided with a 9.0 nozzle for slow-speed running, said device Vbeing connected by a channel 10with the cylindrical chamber in which is mounted the atomizer; the.slowspeed atomizer 12 is sup- Iplied with primary air by a conduit 1 3, con- 95 nected by a duct 13 opening into the floatv d chamber, having a communication with the atmosphere, as usual. rihe slow speed atomizer delivers the primary mixture into a chan- 1 nel 14, leading into the suction conduit 4 at' 10 Said device comprises a member 20, whose end constitutes the nozzle 7 and which is formed with a venturi 21; the lower tubular end of said member is fitted upon a cylindrical boss of a nozzle 22, having an axial calibrated hole 23 which forms the main jet,

- and is extended by a conduit 24 of larger diameter, ending in a cup-shaped portion 25.

i5 Within conduit 24 extends a small tube 26,

ending in a head 27 of ovoid or other shape, which cooperates with said cup-shaped portion to form an

annular slot

2,8, situated at a determined level below the constant level of the fuel in the iioat chamber. At the lower part of member 20 are formed large apertures 29 for the entrance of primary air, and the cross sectional area between the inner wall of tube 20 and the periphery of the ovoid head 27 is accurately calibrated so as to form a restricted part 30.

As herein represented, the slowspeed` atomizer may consist of a similar arrangement, comprising for instance a member 3l,

having an axial conduit 32, and screwing into a boss 33; its lower tubular part 34 is engaged upon an atomizer 35, having a spherical4 head 36 and pierced with an axial conduit 37 ending in a calibrated orifice 38 forming 'a 'slow-speed jet. A plurality of small linclined conduits 39 lead into the central conduit 37. Large apertures 40 for the entrance of'primary air are formed at the bottom of the tubular part 34.

- The operation-is as follows:

vWhen in the idle position, under head resulting from the difference of level, will flow through the calibrated orifice 23 and 'the annular slot 28, thus filling the chambers 41'42; it then roceeds through channel l0 and fills the s ow-speed device 12; the main atomizing device and the slowspeed device are `.thus both the liquid reaches the level parts. i e

When the en 'ne is started and speeded u to normal speenl r having passed throng od, as will be further the slow-speed 1 n of the engine specified, the su ders draws primary air through theiconduit 6, and the liquid fuel is drawn from the chambers 41-42 into the suction conduit 4 and thence into the engine cylinders.

When the reserve supply of fuel is Aelihausted, the primary air, which flows downwardly through conduit 6 rises in chamber 41 and, when passing through the restricted part 30, is imparted agreat speed. The liquid fuel sprayed out through the -annular slot 28, firstly by reason of the constant head due to the difference of level, and 'secondly in Vthe fuelv and the air,

the liquid fuel,

submerged, and T-T in all these b virtue of the suction, will flow out in the form of a sheet which is spread in the restricted part 30 and meets the thin cylindrical stream of air which Hows atchigh speed in this portion, at an angle of about 90; this causes an abrupt impact between which assures an approved atomizing of the fuel and the homogeneity of the primary mixture. This latter is drawn into the admission conduit 4 of the/engine, and mixes with the secondary air, then proceeding to the cylinders.

. If the driver now closes the 'throttle 9, the suction ahead of the throttle is annulled, and the fuel which continues to b'e supplied under the effect of the static head, will again fill the chambers 41-42 and will flow through channel 10 to the slow-speed device. In the closed position of the throttle 9, a strong vacuum prevails in the region 43 in which the slowspeed channel 14 opens into the suction conduit 4, thus causing primary air to enter through conduit 13; this primary air, when rising between the head 36 of the slow-speed atomzer 12 and the tube 34, will acquire a great speed, thus effecting a most approved atomizing of the liquid fuel issuing through the small conduits 39.

In addition to this excellent atomizing of the fuel, this arrangement will also provide for a great increase of the amount o f primary air at the expense of the secondary air, thus reducing the inertia or momentum of the mixture and facilitating the speeding up of the engine. This possibility is due to the fact that carburetors, in which the orifices for the enftrance of primary air are located beyond the' nozzle, and hence cannotl be much enlarged, as -this would unduly reduce the vacuum on the nozzle. Y A

Obviously, this construction is y way-of example; it is applicable to carburetors of the horizontal type (Fig. 20) as well as to carburetors of the vertical type. The invention is independent of the construction ofthe slow-speed nozzle, which may be of any known type.

The head 27 ofthe atomizer, instead of having al1-ovoid shape, may be given a spherical, tapered, cylindrcal or stepped shape, or any other suitable form, adapted to provide a given solely restricted flow section for the primary air at the spraying level. By way of example, Figures 2l and 4 show an atomizer with tapered head; and Figures 3, 5, '6 and 7 relate to Vatomizers with-round heads (like the head 36 of the slow-speed atomizer of Fig. l), as well -as various /dispo's'tions of for spraying the fuel.

slots or apertures Instead of sprayin the fuel in the formof a spread-out sheet, t rough an annular slot,

this may be delivered, as above indicated for the slow-speed nozzle of Figure 1, through radial ducts in such manner as to produce a certain num er of radial jets, or the annular slot may be combined vwith radial ducts. Thus, in Figure 4, the liquid fuel enters the annular slot 28 through inclined ducts 454; the same is shown in Figure 5, which relates to a modification. In Figures 6 and 7, the channels 46 for the discharge of the fuel are pierced horizontally in the plane of the annular slot 28. Obviously, many other modifications may be provided for spraying the liquid in a spread-'out sheet, or. in radial jets having anangle of about 90 with reference to the direction of` the current of primary air.

In `like manner, the mounting of the atomizer may be different; thus, as' shown in Figure 8, member 7, instead of being screwed into the boss 3, has a shoulder 48 in contact with the fianged edge 49 of a sleeve-50, whose threaded lower ,part is screwed upon a member 51, screwed into the boss v3, and having large apertures 52 for the entrance of primary air. Extending from member 51 is a tube 53, which forms a bafile for the primary air between the

orifices

52 and 29.

1instead of spraying the fuel from the center lto the periphery, it may be sprayed from the periphery towards the center, as shown in Figure 9; herein the fuel supplying conduit 2 has a calibrated orifice or jet 55 and opens into an annular chamber 56, surrounding a primary air conduit 57 and in communication therewith through orifices 59. Within conduit 57 is a concentric core 58, which may have the shape of two cores with a common base, thus leaving an annular passage whose cross-section decreases up to the spraying point,`at which the primary air assumes its maximum speed. llfhe fuel may also. be sprayed through a slot at the level of the restricted part 59.

Fig. 10 shows an arrangement in which the liquid is sprayed from the periphery towards the center by means of the last mentioned device on the one hand, and from the center to the periphery by radial ducts 60 pierced in the central core 58 and communieating with a second liquid supplying conduit 61, on the other hand.

The perfectly homogeneous primary mixture, in which the liquid is finely atomized by means of the aforesaid de ices is preferably delivered into the engine suction conduit by means providing for the spreading of the'current of primary mixture, this furthering its diffusion into the secondar air. 4This re- ,sult is obtained in Figure 1 y the diverging cone of the venturi 21. In horizontal carburetors, it is possible to use the device shown in Figs. 11, 12 and 20, in which the primary mixture issues through a round head 65, slotted at 66 in a direction perpendicular to the direction of flow f of the sec-v ondary air. The primary mixture issues radially in a fan-shaped sheet, and is subjected to the abrupt impact of the current of secondary air, and thus a homogeneous mixture is more readilyobtained. Figs. 13 and 14 show a similar disposition, but herein the head 67 is reduced to a hemisphere, with the convex side turned towards the intake of the suction conduit.

Figure 15 shows a device for the exit of the primary mixture in the case of a vertical `carburetor, wherein the structure of the head 68 is similar with that of the head of the atomizer used for the primary mixture. This figure also shows, by' way of example, several atomizers arranged in

series

69, 70, 68; the primary air enters through conduit 6 and apertures 29, and is divided into two currents, one of which flows at high speed at the level of the slot 73 of atomizer 69 and the,

resulting mixture issues through the slot 71 of the second atomizer 7 O, before whichthe second current of primaryair flows at high speed, and the final mixture is discharged through the slot 72 of the head 68I into the intake conduit 4 of the engine.

lin the carburetor above described, the excessive enriching of the fuel mixture occurring at high speeds of the engine is partially corrected due to the fact that the fuel is s rayed under va constant head h (Fig. 1), which constitutes the factor of correction. However in certain cases, and chiefly in order to reduce the amount of fuel stored during stoppage in the recesses 41-42 of the sprayer, it may be necessary to reduce the diderence of level It and hence to reduce the relative value of the correcting factor constituted by this level dierence.

To obviate this defect, and according to another feature of the invention, to the main sprayer 23 (Figures 16, 17 and 18) may be added one or more correcting orifices 80 communicating with the fuel supply conduit 2 or 8l ahead of the main jet 23 and opening at a point near the apertures 29 for the abundant supply of primary air. Primary air (Fig. 16) entering through said apertures 29 will lmpinge upon the part 82 of the atomizer,

ythus producing whirls and eddies and reducing the suction or vacuum, and especially as its speed is greater, so that the delivery of orifice 8() will be checked according as the speed of the primary air is higher, that is, as the vacuum in the engine intake conduit is greater. f At the same time, the primary air effects the atom izing of the correcting fuel discharged from said orifices 80. The corv, recting orifice is supplied under a constant head, thus affording another factor'for correcting the composition of the mixture.

As shown in Figure 17, the correcting orifices 8O may be arranged on the axis of the air inlets 29, thus increasing the impeding action of the primary air. The calibrated loaded with some emulsified fuel when passf ing before said correcting orifices. Its density is thus increased, so that the impact of said air against the fuel sprayed out beyond orifices 80 is also increased and, consequently, the atomizaton of the'fuel spray better.

A serious disadvantage in the known carburetors resides in that the primary air abruptly withdraws the supply of liquid fuel stored in the several recesses, when the engine starts ruiming or is speeded up, since the fuel thus taken up in excessive quantity is not properly atomized and is distributed irregularly among the engine cylinders; the excess fuel removes the lubricating oil from the movable lparts and mingles with the oil in the crankcase, thus causing gripping andvwear and carbon deposits dueto an excess of fuel in the mixture. c

To obviate such defects, the reserve supply of fuelv(Figs. 19421) is'coiitained in recesses or chambers which are protected against direct suction by the primary air, at least as concerns the major part of the volume of fuel, for causing a progressive withdrawal of the reserve fuel, and means are provided for properly atomizing this reserve fuel by the primary air. The simplest device for this purpose is shown in -Figure 19. A partition 90 separates chamber 41 from the space 91 serving for the normal flow of primary air entering through the apertures 92, and the lower part of said chamber 41, which communicates with the annular space 42 by the openings 93--94, is connected by one or more ducts 95 with the conduit 24, situated beyond the sprayer 23. This arrangement has the following advantage. When the engine is started or speeded up, primary air iirst iows through the apertures 92, thus expellin the small amount of fuel stored above partition 90; then the primary air forces the fuel contained inthe annular space 42, as well as thefuel contained in space41, (by means` of the orifices 93-94) f through the duct 95 into the conduit 24; this fuelthus issues through the slot 28, orthe radial ducts of the atomizer, and is subjected l to the actionV of the currentV of primary air entering through the apertures 92, as in the case of Figure 1. Hence, the stored fuel. is l where'it-meets the ascending current of air entering at `6 and owing through orifices 92, the primary mixture being discharged throughthe Venturi nozzle 7 and head 65 into the engine intake conduit 4. In normal operation, primary air also enters duct 24 throughan opening 93 intol which opens a correcting orifice connected with the fuel supply ahead of jet 23; the flow through this orifice is checked by the current of primary air flowing through opening 93, which may be followed, for this purpose, by atapered conduit 96. In normal operation, the primary air entering through duct 93 atomizes the correcting fuel issuing from the orifice 80, and reduces the delivery therethrough as the enginespeed increases; the atomization of the fuel from orifice 80 is achieved by reason of its How through the atomizer 28. Orifice 93 also, serves, when starting, to cause the reserve supply of fuel stored up in cavity 41, to enter duct 24 and tobe atomized through the atomizer.' l

In Figure 21, the. correcting fuel, instead of being led vto the atomizer through the conduit 81 of the main jet 23,1iows through a parallel conduit 98, opening into the slot 28 of the atomizer having a calibrated orifceor jet 99. This figure shows another,l disposition of the correcting orifice 80.

' In Figure 22, only the conduit 24 of the main jet 23 opens into the-annular slot 28 of the atomizer, whilst the separate conduit 98 for the reserve fuel opens through a calibrated orifice-or jet 99 at the top of the atomizer head 27.

In certain embodiments of the invention, and more'specifically when the fuel is supplied by two diierent paths (as in Figures 10',

18, 17, 18,19, 21, 22) use may be made of two' different fuels, namely a light fuel to further f the speeding .up and a heavy fuel` for the power jet; thus, at slow speed running, the mixture will contain a greater proportion of light hydrocarbons,whilst the proportion of these latter 'will decrease as the speed rises, and this furthers the ignition by changing the ignitingpoint in a suitable manner. This cannot be done when the light and heavy fuels are prelminarily mixed together, since said fuels generally lack miscibility.

This fuel supply method may be used, iii

the case of Figure 10,-by feeding heavy fuel zu? conversely. The arrangement should be such that the storage chamber 101 will be filled at rest with light fuel, which can be supplied for instance by a second float chamber` in which the constant level for the light fuel is properly selected according to the relative densities of the twofuels.

In Figures 16, 17, 18, 20, A21 and 22, the correcting orices 80 can be used to supply the light fuel, by connecting said orifices with suitable feeding conduits in communication with a second float chamber. `The two fuels' can be atomized after they have been mixed together, as in the case of the carburetor shown in Figure 20, or they may be e separately atomized, as in the case of Fig- Ato Obviously, the invention is not limited to the details of construction herein specified, and the carburetors above described are susceptible of numerous modifications without departing from the scope of the invention.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. 1n a carburetor, a constant level fuel tank, an intake pipe adapted to be connected with an engine and an atomizer for the primary fuel mixture, saidatomizer embodying means, below said constant level, for spraying fuel from said tank in a spread out spray,

an annular conduit surrounding said spraying means, opening into said intake pipe and having a restricted cross section at the spraying level, and air inlet means opening into said conduit for supplying primary air thereto, the arrangement being such that the air iow assumes an increased speed and a smaller thickness through said restricted part and meets'the fuel sprayat an angle substantially equal to 90.

2. in a carburetor, a constant level fuel tank, an intake pipe adapted to beconnected with an engine, and an atomizer for the primary fuel mixture, said atomizer embodying a conduit having an air inletl and opening into said intake pipe, a central member in said conduit and leaving a restricted lpassage between it and said conduit below said con'- stant level, a spray outlet in said passage and means for connecting said tank with said outlet, whereby fuel isr sprayed into said passage in a spread out sheet and meets at a substantially right angle a thin flow of primaryair entering through said inlet and'fhaving an increased speed through said passage.

3. A carburetor as claimed in claim 1 wherein said spraying means consists of several radial circular holes opening into a continuous circular slot located in a plane substantially at right angles with said conduit.

4. Ina carburetor as claimed in claim 1, a

primary mixture discharge nozzle at the end of said conduit and within said intake pipe, said nozzle having a convex surface facing the inlet of said intake pipe.

5. In a carburetor as claimed in claim 1a second atomizer surrounding said irst menltioned atomizer and embodying means, below said constant level, for spraying the primaryl mixture from said conduit in auspread out spray, an annular conduit surrounding said latter spraying means and having a restricted cross-section at the spraying level, and'air inlet means opening into said latter conduit for supplyin g air thereto.

V6. In a carburetor, a constant level fuel tank, an atomizer for the primary fuel mixture and a fuel supply channel between. said tankand said atomizer, .and having a calibrated orifice therein, said atomizer embodying means, below said constant level, for spraying fuelfrom said tank in a'spread out spray, as annular conduit surrounding said spraying means and having a restricted cross section at the spraying level, air inlet means opening into said conduit for supplying primary air thereto, and a correcting orifice opening into said channel, ahead of said calibrated orice, and into said conduit, adjacent said airinlet means, whereby the delivery of said orifice is counteracted by the iiow of entering air.`

7 A carburetor as claimed in claim 6, wherein said correcting orice opens into said conduit substantially in the axis of said air inlet means. y

' 8. v A carburetor as claimed in claim 6, wherein said. correcting orifice is inclined towards said air inlet means in a direction contrary to the air flow.

9. 1n a carburetor, a. constant level fuel tank, an atomizer for the primary fuel mixture and a fuel supply channel between said.-

ing Jmeans, below said constant level, for

spraying fuel from said tank in a spread out spray, an annular conduit surrounding said spraying means and having a restricted cross section at the spraying'level, air inlet means opening into said conduit for supplying primary air thereto,and a duct for connecting said conduit ahead of said spraying means with said supply channel beyond said cali-A brated orifice, whereby any fuel contained in said conduit is forced through said duct, said channel and said spraying means.

10. In 'a carburetor Las claimed in claim 9, a correcting orifice opening into said duct and into. said supply channel ahead of said cali- /brated orifice and adapted to deliver fuel into the air current passing through said duct into said channel.' 4 v l l1. In a carburetor, a constant level fuel` tank, and an atomizer for the primary fuel stant level, for spraying fuel from said tank in a spread out spray, an annular conduit surrounding said spraying means and havin a restricted cross section at the spraying leve 5 Vair inlet means opening into said conduit for suphplying primary air thereto, a correcting Y or ce openmg into said conduit toward said air inlet means, and a further fuel supply connected Withsaid correcting orifice. 10 12. A carburetor as claimed in claim 2, wherein said central member has an ovoid shape, the 'radial size of said member being smaller beyond said spray outlet than ahead of the latter. 1L In testimony whereof I have signed my name to this specification;

y EUGENE MATHIEU.