US2541316A - Carburetor - Google Patents

Description

Feb. 13, 1951 A. H. WINKLER 2,541,316

CARBURETOR Original Filed July 51, 1943 2 Sheets-Sheet l INVENTOR ALBERT H W/NKLER "4 M BY WM Feb. 13 1951 A. H. WINKLER 2,541,316

CARBURETOR I Original Filed July 31, 1943 2 Sheets-Sheet 2 INVENTOR ALBERT H l V/A/KLER JQ (3M4 Patented Feb. 13, 1951 CARBURETOR Albert H. Winkler, South Bend, Ind., assignor to Bendix Aviation Corporation,

South Bend, Ind.,

a corporation of Delaware Original application July 31, 1943, Serial No. 496,896. Divided and this application June 20, 1945, Serial No. 600,469

11 Claims. (01. 2s1 s9) This invention relates to fuel feeding systems for internal combustion engines and more particularly to devices or systems in which liquid fuel is supplied thereto under superatmospheric pressure and is metered and discharged while being maintained under pressure, this application being a division of applicant's co-pending application for a Carburetor. U. S. Patent No. 2,457,765, issued December 28, 1948.

One of the principal objects of-the invention is to provide a simplified device of this character which may be built at reasonable cost and which is capable of accurately regulating the fuel supply to maintain a proper fuel to air ratio through wide ranges of engine load, speed, and variations in altitude such as are experienced with an aircraft engine.

Another object of the invention is to eliminate boiling of the fuel under high temperature or altitude conditions to thereby insure accurate metering. This is accomplished by maintaining a fuel under positive pressure until it is discharged-into the air supply to form a combustible mixture for the engine.

In fuel feeding systems of this character it is known to use a metered fuel control valve of the poppet or unbalanced type. Suction in the inductionpassage will therefore affect its position, a result that may have particularly disadvantageous results when the engine is operating in its idling range (the induction passage suction then being relatively high) and the quantity of fuel mixture supplied is relatively small. Under such conditions a very slight variation in the position of the fuel valve will cause a relatively great change in the ratio of fuel to air in the mixture.

It is therefore another object of the invention to provide a device of .this character wherein fuel metering is substantially unaffected by variations in suction in the induction passage and the mixture is maintained at a substantially constant richness although manifold pressures may vary through rather a wide range. This is effected by providing a fuel nozzle including an emulsion chamber wherein substantially atmosphericpressureor the pressure at the entrance of the carburetor; which may be modified by impact or suction tubes, is maintained so that metering of fuel delivered thereto is substantially unaffected by variations in the suction in the induction passage, the emulsion being delivered to the induction passage through a passage of limited flow capacity, which particularly during idling is subjected to conditions of critical flow.

Another object of the invention is to provide a device of this character wherein the nozzle is provided with means adapted to direct and evenly distribute fuel to the discharge groove thereof.

Still another object of the invention is to provide a device for delivering a mixture of a plurality of fluids wherein variations of suction on the delivery end of said device will not appreciably affect the operation of the device.

Other objects and advantages of the invention will be readily apparent to one skilled in the art from the following description taken in connection with the accompanying drawings. After considering the embodiments disclosed, skilled persons will understand that many variations may be made without departing from the rinciples disclosed; and I contemplate the employment of any structures, arrangements, or modes of operation that are properly within the scope of the appended claims.

In the drawings:

Figure l is a diagrammatic sectional view of a carburetor embodying the invention;

Figure 2 is an enlarged view in section of the discharge nozzle shown in Figure 1;.

Figure 3 is an enlarged partial view in section the idle and economizer needle valve;

Figure 4 is a view taken on line 4-4 of Figure 2; and

Figures 5 and 6 show nozzle.

Throughout the drawings, similar reference characters represent similar parts although where such parts are modified in structure and operation they are given a further differing reference character.

With reference to Figure 1, there is shown a main'body member In which contains an induction passage l2 therethrough having an air inlet l4 and an outlet I6, the air inlet being provided with an outer surface I 8 to which an air scoop (not shown) opening in the direction of travel may be secured and the outlet being provided with flanges (not shown)- for securing the body member ill to the manifold of an internal combustion engine or to the inlet of a supercharger if one is used between the carburetor and the manifold. If desired, a supercharger may be used anterior to the body member ID either in place of or in addition to a supercharger posterior to said body member. A venturi 20 having separable inlet and outlet sections is positioned in the induction passage adjacent the inlet It and is formed with an annular chamber 22 which communicates with the interior of the modifications of the venturi through annular slot 24 to be thereby subjected to Venturi depression. An annular chamber 26 is in free communication with the air entering the venturi through an annular opening 28, the opening 23 being preferably subjected to the impact pressure of the air supplied to the venturi. A throttle 30 is pivotally mounted in the induction passage posterior to the venturi and is adapted to be manually actuated to control the air flow to the engine.

The fuel flow to the engine is regulated or controlled by an unmetered fuel pressure control unit or regulator, indicated generally at 32, which regulates or determines the fuel pressure on the upstream side of a fuel metering unit, indicated generally at 34, and by a discharge nozzle assembly indicated generally at 36 which regulates or determines the pressure on the downstream side of the metering unit 34. If desired, a metering orifice of fixed size may be used instead of the metering unit 34.

The interior of the regulator unit 32 is divided into three chambers 40, 42 and 44 by diaphragms 46 and 48. As shown the diaphragms 46 and 46 have an area ratio of although, as will be apparent hereinafter any desired area ratio may be used. The center portions of the diaphragms are supported by thin plates 50 between which the diaphragms are clamped by centrally disposed cylindrically recessed rivets 62 and 54. Washers 66 are'preferably provided under the deformed end of the rivets so that the thin plates will not tear loose from the riveted over portion of the rivets. The ends of a pin or rod 58, freely received in the recesses of the rivets, are preferably provided with rounded ends to form angularly adjustable one-way connections with the diaphragms whereby slight misalignment of the diaphragms may be accommodated without. binding. This construction also greatly facilitates assembly and disassembly of the control unit 32.

Chamber 40 is provided with a fuel inlet port controlled by a valve 60 and receives fuel from a. source of fuel under pressure, such as a fuel pump, through a pipe 62. The valve 60 has a pin-like extension projecting into the chamber 40 in position to be engaged by the head of rivet 62 whereby movement of the diaphragms to the right opens the valve. A spring 64 urges the valve to its closed position. A spring 66 is mounted at one end in the chamber 44 and has its free end received in a spring retainer portion of a lever 68 pivotally mounted at one end and having a crimped center portion normally engaging the head of rivet 54 and urging the diaphragms to the right in a direction to open the valve 60. The spring 66 may be rendered inoperative, when the engine is to be stopped, by a plunger I which upon downward movement thereof engages the free end of lever 68 and moves the lever to the left against the force of spring 66. The lever 68 will thus move out of engagement with the rivet 64 whereby the spring 64 may close the valve 60 and out off the fuel supplyto the engine. In order to eliminate vapor, a pipe 12 having a restricted communication with the top of chamber 40 is preferably provided which leads back to the fuel supply tank. v

The chamber 42 of the regulator unit 32 is connected to the Venturi annulus 22 by means of a pipe I4 and passage I6 and is therefore subjected to a pressure primarily derived from the throat of the venturi 20. A restriction 18 may be provided in passage I4 if desired. The chamber'42 is also connected to the air scoop or Venturi entrance by means of a passage controlled by a manual mixture control valve 82, a passage 64, and the annular chamber 23. The chamber 44 of the regulator unit 32 is connected to the annular Venturi entrance chamber 26 by a branch passage of the passage 84 and is therefore subjected to a pressure primarily derived from the Venturi entrance. A restriction 06 may, if desired, be provided in the branch 85. The chamber 44 is also connected to the Venturi annulus 22 through passages 90, 92 and 14, the communication between passages and 92 being controlled by a valve 94 of an automatic mixture control unit 06. Unmetered fuel entering the chamber 40 of the regulator from the fuel inlet 62 is transmitted through a pipe 98 to a chamber I00 of the fuel metering unit 34, and thence through the metering unit to a pipe I02 leading to a chamber I04 of the discharge nozzle 36.

The fuel metering unit 34, which determines the effective area of the fuel metering restriction under various conditions of operation, may be formed as a part of the main body I0, or of the regulator 32, or may be a separable unit secured to the body or regulator as desired. A diaphragm I06 separates the chamber I00 from a chamber I08 and is secured to a metering valve IIO (best shown in Figure 3) slidable in a plug H2 and having a double stepped end H4, H6 cooperating with, a metering orifice IIB formed in the plug II2. If desired, a second orifice I20 may be provided to limit the flow of fuel when the valve H0 is entirely withdrawn from the orifice I I8. As shown the orifice I20 islocated in the plug II2; however, it may be placed at any desired point in either of the passages I02 or 98. The chamber I 08' is connected to the Venturi annulus 22 by means of a pipe I22 and the passages I4 and I6.

A cup member I24 forms a stop, limiting movement of diaphragm I06 to the left, and may be adjustably mounted as by threading. A piston I26 is slidably mounted in the cup member I24 and projects therethrough into abutting relation with the diaphragm I06 of the valve I I0 to thereby limit the permissible movement to the left of diaphragm I06 under the influence of the fuel pressure in chamber I00. The piston I26 is provided with a reduced diameter extension I28 adapted to be engaged at idle by a cross bar I30 adjustably secured to a slidably mounted rod I32 which is urged to the left by a spring I34 and is moved to the right at idle by a throttle lever finger I35 engaging a flange I38 on the rod I32. A stop I40 limits movement of rod I32 to the left at such times as the throttle is open beyond its idling or near idling positions. A washer I42, slidable within the cup member I24, is urged to the right against the bottom of the cup member by a pre-loaded spring I46. The washer is adapted to engage the shoulder of piston I26 to limit the movement to the left of said piston, diaphragm I06, and valve M0 to the left only sufliciently far to withdraw the step I I4 from the orifice H8. During high power operation, however, the high unmetered fuel pressure in chamber I00 and the low Venturi pressure in chamber I00 create a sufficient pressure differential across the diaphragm I06 so that the spring I46 is further compressed and step H6 at the end of valve H0 is completely withdrawn from the orifice I I8.

Thus during idling, with the parts as shown in Figures 1 and 3, the step II4 cooperates with the orifice I I8 to limit the area for fuel flow. As the throttle is opened through the near idling range the valve II 0 moves to the left until the piston I28 engages the washer I42, at which time the step II8 cooperates with the orifice II8 to limit the area for fuel flow during normalcruising operation. At high power output the step 8 is completely withdrawn from the orifice H8, at which time said orifice I I8, or the orifice I20, or both, determine the effective fuel metering area.

Fuel passing through the metering unit 34 is transmitted through a pipe I02 to a chamber I04,

in the discharge nozzle assemblyf38, which is separated from a chamber by a preformed annularly grooved diaphragm I52 connected to a fuel outlet valve I 54 and urged to the right in a direction to close the valve by a spring I58 arranged to be variably loaded by an adjustment screw I58, said chamber I50 being connected to the Venturi annulus 22 by the passage 18. The stem of valve I54 is of triangular cross section or otherwise relieved to permit fuel flow therepast and is slidable within the nozzle bar I80. In this arrangement the valve I54 is not fixed to the diaphragm I52 but is maintained in abutting relation therewith by means of a light spring I82 which constantly urges the valve I54 to the left. This arrangement eliminates any tendency for the valve to bind in its valve guide and seat member I84 as a result of misalignment between the diaphragm and the guide member.

The discharge nozzle, as best shown in Figure 2, comprises an upper dome-shaped member I88 and a lower cone-shaped member I88 which is attached to a depending screw portion I10 of the member I88, the latter also having a bore I12 in the upper end of which is received a screw plug I14 which closes said upper end. Fuel is delivered to the nozzle by a fuel conduit indicated at I18, the flow therethrough being controlled by a valve, the valve I54 shown in Figure 1. The fuel passes into bore I12 through a passage I18 and thence is discharged through passages I80 into a chamber I82 formed in the upper end of the member I88. Air is bled to the nozzle through an air passage I84 'and reaches chamber I82,-

through calibrated passages I88 which branch from the passage I84. The fuel emulsion which is formed in the chamber I 82 is delivered into the induction passage I2 from an annular calibrated opening I90 which forms the critical flow restriction of the nozzle.

An acceleration pump indicated at 202, which may be provided, if desired, includes a suction chamber 204 connected through pipe 208 with the induction passage I2 posterior to the throttle. A diaphragm 208 urged to the left by a spring 2I0 separates, the suction chamber 204 from a fuel chamber 2I2 connected through a pipe 2I4 with the fuel chamber I04 of the discharge nozzle 38. During periods of high engine suction operation the diaphragm 208 is moved to the right and the fuel robbed" from the chamber I04 is drawn into the chamber 2| 2. Upon a loss in engine suction as upon acceleration, the spring 2I0 forces the diaphragm to the left and pumps fuel from chamber 2I2 to the nozzle chamber I04 thereby temporarily richening the mixture. An adjustable stop 2I8 is provided whereby the stroke of the diaphragm 208 may be varied.

The automatic mixture control unit 98, which is responsive to variations in altitude, includes a plug 220 which carries a seat portion 222 and is screwed into any desired fixed member, which may be the body I 0. The stem of valve 94 is slidably received within the plug 220 and is secured to an end closure member 224 of a corrugated bellows 228, the other end of which is secured to a base 228 to which a cap 230 is also secured. The bellows and cap form walls of a sealed chamber 232 which may be evacuated to any desired degree. By controlling the degree of evacuation, the pressure and temperature responsiveness of the bellows may be correlated as desired. If desired a quantity of fluid may be used in chamber 232 to aid in obtaining the desired temperature responsiveness. The base 228 is threadedly secured to the plug 220 and is separated therefrom by shims 234, the number or thickness of which may be readily varied to ad-, just the zero setting of the valve 94 relative to the seat portion 222.

oppositely disposed ports 238 connect the interior of the bellows 228 with annular chamber 288 whereby the pipes 90 and 92 may communicate with the interior of the bellows, thereby making the control unit 98 responsive to changes in the temperature and pressure of the air entering the venturi. The unit 98 may, if desired, be placed closely adjacent to or in the air inlet so as to be in direct contact with the entering air. Also if desired the interior of the bellows 228 may be connected directly to the inlet.

The calibrated passage interconnects the chambers 42 and 44 and is controlled by the spring closed manual mixture control valve 82 adapted to be opened any desired amount from the pilot's compartment by a cable actuated member 250. The stem of valve 82 is provided with a collar 252 which engages a pivoted lever 254 to force the plunger 10 downwardly when the mixture control valve is moved beyond its wide open or lean position to its idle cut-off position.

Operation The operation of the device disclosed in Figure I is as follows:

Assuming the carburetor has not been filled with fuel and the idle cut-off plunger 10 is in its upward position as shown, the spring 86 will urge the diaphragms to the right and open the valve 80. Fuel under pressure supplied to pipe 82 enters and fills chamber 40 and flows through the unit 34 and pipe I02 to the chamber I04. As the pressure in chamber 40 increases it acts against the diaphragm 48 and tends to compress spring 88 whereby the valve 80 tends to close. Fuel under pressure supplied to chamber I04 acts on diaphragm I52 and tends to open valve I54. The screw I58 is normally adjusted to compress spring I58 to such a point that a slightly lower pressure is required in chamber I04 to open the valve I54 than is required in chamber 40 for sufflciently compressing the spring 88 to permit the valve 80 to close. Once the carburetor has been fully filled with fuel, fuel will therefore slowly spill from the discharge groove unless the lever 250 is actuated and the plunger 10 forced downwardly to compress spring 88 and so allow valve 80 to close. Although the screw I58 has been described as being adjusted to permit valve I54 to open at a pressure somewhat less than the closing pressure for valve 80, it will be apparent that by screwing the adjustment screw I58 in or out the pressure in chamber I04 required to open valve I54 may be made greater than, equal to or less than the pressure required in chamber 40 to permit the valve 80 to close. It will also be apparent that the actual value or degree of the fuel pressures will be determined by the strength of the springs 88 and I58, the pressure required being greater as the strength of the spring is increased.

It has generally been found desirable to adjust the discharge nozzle spring I55 sufficiently weaker, in proportion to the area of the diaphragm I52, than the spring 66,-in proportion to the area of diaphragm 46, so that at idle an excessively rich mixture is obtained, and then to decrease the richness of the idling mixture by decreasing the effective area of the metering orifice H8 during idling operation. It is for this reason that the valve I I0 and the rod I32 function to reduce the metering orifice area at idle. By controlling the rate at which the valve III! is permitted to move to the left as the throttle is opened from its idle position, any desired near idling mixture richness can be obtained.

During operation, assuming the area ratio of the diaphragms 4B and 46 is equal to two, the

regulator unit 32 functions to maintain a dif- 22 is transmitted to the chamber 42, where it results in an equal increment increase in the unmetered fuel pressure in chamber 40, and is transmitted to chamber I04, where it results in an equal increment decrease in the metered fuel pressure. ferential pressure is increased in amount double the increase in the air differential. Similarly a given increase in the entering air pressure in the chamber 26 is transmitted to chamber 44 and since it is applied to the diaphragm 48 having twice the area of diaphragm 46, the unmetered fuel pressure in chamber 40 is increased an increment double the increase in entering air pressure.

Although the diaphragms 48 and 48 are shown as having a two-to-one area, relationship, they may be of any other desired area ratio, in which case the fuel metering differential pressure will be maintained at some multiple, other than two, of the air differential pressure. the area of diaphragm 48 is three times the area of diaphragm 46, the fuel differential will be maintained equal to three times the air metering differential. Or, if diaphragms 46 and 48 are of equal size, the fuel metering differential pressure is maintained substantially equal to the air differential pressure. In any event, the fuel and air differential pressures are maintained in con- Consequently the fuel metering dif- For example, if

fuel metering, is substantially unaifected by variations in the suction surrounding the nozzle. In addition, the restricted annular opening I90 functions as a critical flow nozzle, relative to the air bled to said nozzle, at low manifold pressures corresponding to idling, so that fluctuations in manifold pressure at or above said critical flow point, for a given fuel flow as determined by the regulator, are ineffective to vary the quantity of air being drawn through the passages I84 and I86. By this means a mixture of constant richness is provided even though the idling manifold pressure varies through rather wide limits.

It is generally desirable to provide the pilot with a manual mixture control so that he can vary the richness of the mixture between predetermined limits. For this purpose the callbrated passage 80, controlled by the tapered valve 82 is provided, which with the valve closed corresponds to a rich setting. As the .valve 82 is opened, air is bled from the air scoop chamber 44 into the Venturi chamber 42 whereby the differential pressure between these chambers is reduced an amount depending upon the extent the valve 82 is opened. This in turn reduces the unmetered fuel pressure in chamber 48 required to maintain the diaphragm assembly in an equilibrium position, thus reducing the fuel metering differential and consequently reducing the richness of the mixture for a given air flow. With the valve 82 completely withdrawn the carburetor is in its full lean position, the effective area of passage 80, as limited by the seat of valve 82, determining the maximum permissible bleeding action.

The automatic mixturev control unit 86, or altitude control unit, as it is sometimes referred to, is provided to maintain a constant mixture richness with variations in altitude, and functions on substantially the same air bleed principle as the manual mixture control. Upon a decrease in the density of the air entering the venturi, as by increase in altitudethe differential between the en- 0 into the Venturi chamber 42 to thereby reduce stant proportion and therefore constant fuel to air proportioning is obtained.

In order to minimize the disturbance of the ratio of fuel to air by induction passage suction on the valve I54, which is, of the unbalanced type,

a critical flow nozzle, one embodiment of which is shown in Figures 1 and 2. is provided and constitutes an important element of the present device. In this nozzle the emulsion chamber I82 is freely supplied with air through the passages I84 and I86 at substantially atmospheric or entering air pressure and said emulsion chamber is connected with the induction passage by restricted calibrated opening I90. Therefore, as the opening I90 is one of limited flow and the chamber I82 is freely supplied with air at atmospheric or entering air pressure, the pressure in chamber I82 is maintained substantially constant at said atmospheric or entering air pressure regardless of variations in induction passage suc-.

the differential pressure which would otherwise exist between the chambers 42 and 44, whereby the unmetered fuel pressure in chamber 40 is correspondingly decreased. By properly contouring the valve 94, the differential in the air pressures in chambers 42 and 44 are so controlled that the fuel supplied to the engine remains constant for a given weight of air flow per unit time even though the entering air density changes. Automatic altitude compensation is thus obtained.

With the orifice 86 positioned as shown and properly proportioned relative to the orifice I0, the manual mixture control will function primarily to vary the pressure in chamber 42 to thereby vary the differential between the pressures in chambers 42 and 44; whereas, the automatic mixture control 96 will function primarily to vary the pressure in chamber 44 to thereby vary said differential. vIf desired, however, restriction 88 may be eliminated and restriction I8 placed in the passage 14 to the left of passage 02. in which case both controls would tend to have their major effect upon pressure in chamber 42. Other arrangements of the restrictions may be used if desired.

when the engine is to be stopped it is desirable to cut oil all fuel flow thereto so that it will not continue to run, as a result of pre-ignition, after the ignition is turned off. To accomplish this end, the valve 82 is moved upwardly beyond its full lean position to an idle cut-off position at which the plunger 10 is forced downwardly by the lever 254 whereby the spring 66 is compressed and the light spring 64 is able to fully close valve 60.

The embodiment of the invention shown in Figure includes an upper nozzle member 214 of generally hemispherical shape and a lower member 216 of a somewhat conical shape attached to a depending screw 218 integral with the member 214. The large ends of members 214 and 216 are adjacent to each other and the member 214 is provided with an enlarged bore into which is screwed a vertical upstanding portion 280 containing fuel and air passages 282 and 284 respectively, which extend longitudinally therein. The upper end of the fuel passage 282 is closed except for a connection with a fuel delivery conduit 286, and the upper end of the air passage 284 is closed except for a connection with an air-bleed conduit 288. The lower end of the passages 282 and 284 deliver fuel and air respectively into an emulsion chamber 290 formed in the member 214 and the emulsion is delivered to the induction passage I 2 through orifices 292 and a suitably calibrated annular passage 294 between the upper and lower members 214 and 216 respectively, the point of limited or critical flow being in the annular opening of said passage 294. If desired, in this form of the nozzle, the diameter of the large end of the member 216 may be somewhat smaller than the large diameter of the member 214 so that the edge of the latter projects somewhat beyond the adjacent edge of the former thus increasing the suction in the passage 294 relative to that of the induction passage. While the limited or critical flow in this embodiment of the device isthe passage 294, the nozzle may be otherwise arranged so that the passage 294 is wider and the restrictions are passages 292 which may be suitably calibrated for the purpose.

The embodiment of the nozzle shown in Figure 6 is similar to that shown in Figure 5 except that in Figure 6 the member 216 is provided with a chamber 296 in which emulsion is further mixed before being discharged from the annular discharge opening 294 which constitutes the critical flow restriction.

It will be understood that many changes might be made in the form and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages and it is not intended that the scope of the invention shall be limited to the forms shown and described nor otherwise than by the terms of the appended claims.

I claim:

1. In a fuel supply system having an induction passage: a nozzle including a pair of members one of which is substantially hemispherical in shape and the other of which is tapered from a large circular end which is disposed adjacent the larger end of the hemispherical member, in spaced relation thereto, thereby providing a fuel discharge space of limited flow capacity; an emulsion chamber connected with the said space;

means for supplying air to the emulsion chamber; and means for supplying fuel to said chamber. I

2. In a fuel supply system having an induction passage: a nozzle in said passage comprising a pair of members one of which is substantially hemispherical in shape with its rounded surface facing the air stream and the other of which is generally conical in shape and tapered in the direction of air flow, the large ends of said members being adjacent each other and spaced apart to provide a fuel discharge passage of. limited flow capacity; an annular chamber formed in the larger end of one of said members and communicating with said space; means for supplying air to said chamber; and means for supplying fuel under pressure to said chamber, the capacity of said fuel discharge passage being such as to prevent suction in the chamber from rising above a predetermined value.

3. In a fuel supply system having a throttle controlled induction passage: a nozzle including a pair of members disposed in the induction passage, one of said members being rounded and having a flat surface at one end and the other said member being tapered and having its larger end disposed adjacent to the flat surface of the other member in spaced relation thereto, the member having the rounded surface being adapted to extend outwardly of the peripheral edge of large end of the tapered member; an emulsion chamber in one of the members; means for supplying air to emulsion chamber; means for supplying fuel to said emulsion chamber, said chamber being connected with the induction passage through the space between the members, said connection being restricted to limit the flow of emulsion therethrough and so calibrated that suction in the emulsion chamber will not rise above a predetermined critical value.

, 4. In a nozzle for a fuel supply system: a pair of members one of which is hemispherical in shape and the other, of which is tapered and having its larger end adjacent the larger end of the other member in spaced relation thereto; an emulsion chamber within the nozzle communicating with the exterior thereof by means of the space between the members, which space constitutes a passage of limited flow which will limit the value of suction transmitted to the emulsion chamber to a limited critical value; a

fuel passage communicating with the emulsion chamber; and an air passage communicating with said chamber.

5. The invention defined by claim 4 wherein the emulsion chamber is formed in the large end of one of the members.

6. In a fuel supply system having an induction passage: a nozzle in said passage comprising a pair of members one of which is substantially hemispherical in shape and the other of which is generally cone shaped, the large ends of said members being adjacent each other and spaced apart; a chamber formed in the large end of one of the members and communicating with the induction passage by way of a space between said members; a second chamber communicating with the first chamber; means for supplying air to the second mentioned chamber; and means for supplying fuel to said second mentioned chamber, the discharge space between the members comprising a passage of limited flow capacity, said discharge space being adapted to limit the transmission of suction to the second spherical member and connected with the emulsion chamber for supplying air thereto; and a fuel conduit extending from the wall of the induction passage, diametrically from the air conduit, into said hemispherical member and con-. nected with said emulsion chamber for supplying fuel thereto.

8. In a fuel supply system having an induction passage: a nozzle in said passage comprising a pair of members one of which is substantially hemispherical in shape and the other of which is generally cone shaped, the large ends of said members being adjacent each other and spaced apart; an emulsion chamber formed in the large end of one of the members and communicating with the induction passage by way of the space between said members; a support for said members extending longitudinally of the induction passage and having an air and a fuel passage therein communicating with said chamber; an air.

conduit extending radially from one side of the induction passage and connected to said air passage; and an oppositely disposed fuel conduit extending radially from the induction passage wall and connected with said fuel passage; the discharge space between the members being of such calibration as to comprise a passage of limited flow capacity, adapted to limit the transmission of suction to the chamber to a predetermined critical value.

9. A charge forming device including an induction passage, a nozzle disposed in said induction passage for discharging fuel-air mixture therein, a conduit for delivering air to said nozzle, a second conduit for delivering fuel under superatmospheri'c pressure to said nozzle, a pressure responsive valve for controlling the flow of fuel in said second conduit, said nozzle comprising a pair of members one of which is substantially 'minimize the direct effect of the suction in the induction passage on the operation of said pressure responsive valve.

10. A charge forming device including an in-' duction passage, a nozzle disposed in said induc tion passage for discharging fuel-air emulsion therein, a conduit for delivering air to said nozzle. a second conduit for delivering fuel under superatmospheric pressure to said nozzle, a pressure responsive valve for controlling the flow of fuel in said second conduit, said nozzle comprising a pair of members one of which is substantially hemispherical in shape and the other of which is conical in shape, said members having their large ends adjacent and spaced relative to one another, the hemispherically shaped member being adapted to extend outwardly from the peripheral edge of the large end of the conical member, and an emulsion chamber formed in the large end of at least one of said members and communicating with the induction passage by means of the space between said members, said space constituting a passage of limited flow capacity to minimize the direct eiTect of the suction in the induction passage on the operation of said pressure responsive valve.

11. A charge forming device including an induction passage, a nozzle disposed in said induction passage for discharging fuel-air mixture therein, a conduit for delivering air to said nozzle, a second conduit for delivering fuel under positive pressure to said nozzle, a valve responsive to the fluid pressure in said second conduit for controlling the flow of fuel therein, said nozzle comprising a pair of members one of which is substantially hemispherical in shape and the other of which is conical in shape, said members having their large ends adjacent and spaced relative to one another, and an emulsion chamber within the nozzle communicating with the exterior thereof by means of the space between the 'membeis, said space constituting a passage of limited flow capacity to minimize the effect of manifold vacuum on the operation of said pres-' sure responsive valve. I

50 Number Name 1,275,032 Huene Aug. 6, 1918 1,816,756 Whatmough et a1. July 28, 1931 1,979,918 Wahlmark Nov. 6, 1934 1,983,255 Wahlmark Dec. 4, 1934 2,079,436 Dunn May 4, 1937 2,121,506 Mennesson June 21, 1938 2,310,984 Mock et al. Feb. 16, 1943 FOREIGN PATENTS Number Country Date 547,536 France Dec. 18, 1922 ALBERT H. WINKLERQ file of this patent:

UNITED STATES PATENT Date

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