US2310984A

US2310984A - Charge forming device

Info

Publication number: US2310984A
Application number: US243067A
Authority: US
Inventors: Frank C Mock; Edward J Partington
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1938-11-30
Filing date: 1938-11-30
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

Feb. 16, 1943. F. c. MOCK ET AL.

CHARGE FORMING DEVICE Filed Nov. 30, 1938 4 Sheets-Sheet l INVENTORS. FRANK C. MOCK BY EDwaQo J. Pnmmsron ATTO/Q/ViY.

Feb. 16, 1943. F. c. MOCK ETAL CHARGE FORMING DEVICE Filed Nov. 30, 1958 4 Sheets-Sheet 3 ROM SUPERCHHRGEE OUTLET 0R ATMOSPHERE- amos narae Ora VENTDR! THROGT mm. unosrz rzissurza- INVENTORS. Frar-mz C.

Feb. 16, 1943. MOCK ETAL 2,310,984

CHARGE FORMING DEVICE Filed Nov. 50, 1938 4 Shets-Sheet 4 0 .K m 4 w m mmw m z A w W m Gd IIIIY 4 MWQ m H v nR m R 8 my i Y A s. a B K s CM .V m 8 ,Irw, 2 4 #4 M #W 4 6 4 v fag. 7

E: V 4 0 4 $5 I 4 Patented Feb. 16, 1943 CHARGE FORMING DEVICE Frank 0. Mock and Edward J. Partington, South Bend, Ind., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 30, 1938, Serial No. 243,067

19 Claims.

This invention relates to charge forming devices and more particularly to carburetors of the pressure feed type disclosed in Frank C. Mock application Serial No. 202,206, filed April 15, 1938.

A fuel discharge nozzle is used with devices of this type to spray the fuel into the air conduit leading to the intake ports of the engine. From the standpoint of engine performance and operating characteristics it is advantageous to have the fuel delivered from the nozzle in a finely divided or atomized state and uniformly distributed into the air flowing through the conduit.

One of the principal objects of the invention is to provide a discharge nozzle with means for obtaining more nearly uniform distribution of fuel into the air stream.

Another object of the invention is to provide means for obtaining a discharge of finely divided fuel from the nozzle without the use of excessively high fuel pressures.

A further object of the invention is to provide a discharge nozzle which will shut off the flow of fuel when the engine is not running but which will not act as a restriction to fuel flow when the rate of flow is high.

Further objects and advantages of the invention will be apparent from the following description, taken in connection with the appended drawings, in which:

Figure 1 is a diagrammatic sectional view of a device embodying the invention;

Figure 2 is an enlarged sectional view showing in detail one form of discharge nozzle;

Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 2;

Figure 4 is a diagrammatic sectional view of a modified form of the invention;

Figure 5 is a sectional view of a further modifled form of the invention;

Figure 6 is an enlarged fragmentary view of the discharge nozzle valve shown in Figure 5;

Figure 7 is a longitudinal section of a portion of a carburetor equipped with another modified form of the invention;

Figure 8 is an enlarged sectional view of the same taken on the plane indicated at 8-8 in Figure 7.

Although the invention is described in connection with a radial type aircraft engine, it is also applicable to engines of other types or those used for other purposes.

Referring first to Figure 1, the device comprises a carburetor portion having an induction passage Ill leading to a rotary blower or supercharger I! which discharges into the intake manifold'l3 of an internal combustion engine. The induction passage I0 is controlled by throttle l4 which is operated by rod l6. Anterior to the throttle is an air inlet, or scoop I8, which leads to a primary venturi 20 positioned to discharge in the vicinity of the throat of a secondary venturi 22. Said primary venturl is provided with an annular chamber 24 opening into the venturi substantially at its throat and communicating through passageway 25 with the control unit hereinafter described. Secondary venturi 22 is provided with an annular chamber 26 which communicates with the air scoop l8 through a plurality of tubes 21, and with said control unit through a passageway 23.

Posterior to the throttle I4 is a nozzle adapter bar 30 which is generally, though not necessarily, cast integral with a section of the walls of the air conduit l0, and has a cross sectional contour as shown in enlarged section in Figure 3. Although theadapter bar as shown is of inverted streamlined cross section, any cross sectional contour is satisfactory which will produce a region of relatively stagnant air in the immediate lee of the bar (indicated atl3l in Figure 3) when the device is in operation.

A discharge nozzle, shown in enlarged section in Figure 2, is mounted in the adapter bar 30, and comprises a discharge nozzle body 32, securely held and sealed in place in said adapter bar by nozzle retaining nut 33 and packing 34, and provided with a valve 36 secured to a flexible diaphragm 39 by washer 40 and locking nut 4|. Valve 36 is urged toward closed position by a compression spring 42. Posterior to the valve seat is a cylindrical extension 46 of the nozzle" body 32, closed by a screw plug 5| and provided with radial ports 41. A piston is slidably mounted within the extension in such manner that movement of the piston in a direction away from the valve 36 will successively uncover ports 41, such movement being opposed by a compression spring 50 located between said piston and the screw plug 5|.

Fuel under pressure is delivered by the control unit hereinafter described, through passageway 53, whence it flows into annular fuel chamber 54, through a plurality of ports in the nozzle body 32 into nozzle fuel chamber 56 where it acts on diaphragm 39 to open the valve 36 against the force of spring 42. It also acts on piston 45 causing it to move against the spring 50 and thereby uncover two or more of the ports 41 and allow the fuel to discharge into the passage I0. Ports 4'! are drilled in the nozzle substantially parallel to the axis of the adapter bar H 30, so that fuel from these ports is discharged in the lee of the bar 30 and, being temporarily shielded, has opportunity to spread across the width of passage l before being picked up by the air stream. Ports 4'! are preferably arranged in pairs such that motion of piston 45 will simultaneously uncover a port directed to either side of the conduit, although the location and grouping of said ports can be varied if the engine and inlet manifold peculiarities require a nonuniform distribution in the air conduit in order to obtain uniform distribution to the engine cylinders. Ports 4'! may be drilled so as to direct the fuel away from the adapter bar 30, parallel to the bar, or may be inclined slightly toward the adapter bar, as shown, depending on whether it is desirable to deliver the fuel to the central portion of the conduit It or spread said fuel across the conduit.

At low rates of fuel flow the piston 45 is moved toward the valve 36 by spring 50 to such extent that only the first two of the ports 41 are exposed and fuel is discharged only from the said two ports. This results in higher velocity through the ports than would be the case if all the ports were open, thereby increasing the ability of the fuel to approach the wall of the conduit before being entirely carried away by the air stream.

As the rate of fuel flow increases, the fuel pressure in nozzle chamber 56 increases, thereby increasing the pressure on piston 45 and causin said piston to move against the spring in a direction to uncover additional ports 41 and increase the available port area so that the necessary amount of fuel will be discharged without requiring excessive pressure.

The chamber 58 within discharge nozzle cap 59 is vented through passages 51 and G0 and tube 51 to the chamber 24 of primary venturi 20. If desired the tube 51 may be omitted and the chamber 58 vented through passages BI and 60 to the atmosphere in a manner comparable to that indicated at l6| of Figure 4. Venting of the chamber 58 either to Venturl suction or to atmosphere rather than directly to the conduit [0 makes the action of the diaphragm substantially independent of the vacuum present (posterior to the throttle) in said conduit. The relative advantages of venturi and atmospheric venting will de discussed hereinafter.

The control unit casing 63 (Figure l) is divided into five chambers, 64, 55, 66, 61 and 68, by four flexible diaphragms 69, 10, II and 12. The diaphragms are secured at their centers to a control rod 13 by washers l9 and hubs 85 slidably mounted on said rod and locked in position by tightening nut 14 on the end of rod 13. The nut 14 is provided with a ball end which slidably engages bearing recess 15 in the end of casing 63. Control rod 13 is connected, through two balltype universal joints 62, with slide valve 15, which has ports 11 so arranged that axial motion of rod 13 will regulate the effective area for fuel flow from annular fuel chamber 18 into the unmetered-fuel chamber 68.

Any suitable fuel pump, arranged to deilver fuel at substantially constant pressure, may be used to supply fuel to chamber 18, the one shown at 80 being of the sliding vane type and having fuel inlet 8|, fuel discharge passage 82, and bypass channel 83 controlled by pressure responsive valve 84.

Unmetered fuel chamber 68 communicates with metered fuel chamber 61 through passageway 86 containing a calibrated metering orifice .1. Chamber 88 also communicates with chamber .4 through a centrally drilled passage 88 in the control rod 13. Chamber 8'! communicates with the discharge nozzle through passageway 53. Chamber 65 communicates through passageway 2! with chamber 26 in venturi 22 and is therefore subjected to the pressure obtaining at the air scoop I8. Chamber 66 communicates through passageway 25 with the chamber 24 in the primary venturi 20 and therefore subjected to the pressure at the throat of said venturi.

The differential in pressure between

chambers

65 and 66, created by air flow through the conduit I0, under any given set of operating conditions, will produce a resultant force on the control rod 13 tending to move said rod in a direction to open valve ports ll. Since the differential pressure between air scoop and Venturi throat is proportional to the square of the rate of air flow, the resultant force on the control rod created by this differential acting on opposite sides of 9. diaphragm of constant area will also be proportional to the square of the rate of air flow.

Fuel admitted through ports 11 into chamber 68 will flow through passage 86, metering orifice 81, into chamber 51 and thence through passageway 53 to the discharge nozzle 32 from whence it is discharged into the air conduit I0 posterior to the throttle valve l6. Flow of fuel through metering orifice 81 results in a pressure differential across said orifice, which creates a resultant force on control rod 13 which acts in a direction to close valve ports I1 and thereby tends to oppose the previously mentioned force created by air flow through the conduit. Since the pressure differential across the metering orifice is proportional to the square of the quantity of fuel flowing the resultant force on rod 13 will also be proportional to the square of the quantity of fuel flowing. Thus, for any given condition of engine speed and load, the control rod 13 and attached valve 18 will move to a position such that the force on said rod resulting from fuel flow will exactly balance the force applied to said rod resulting from air flow. The squares of the quantities of air and fuel flow, and hence the quantities themselves, are therefore held in constant proportion to each other, the absolute value of the ratio depending upon the relative sizes of the fuel metering orifice 81 and the venturis in the induction passage.

A constant mixture ratio can therefore be obtained throughout the range of airflows used unless otherwise varied by extraneous means such as those disclosed in the Mock application above referred to. One such extraneous means is spring 89, shown in Figure 1 as a weak spring which, when the engine is idling, moves valve 16 toward open position and thus enriches the mixture as is required for idling operation.

To prevent leakage of fuel into the manifold during periods of inoperation the nozzle spring 42 must be sufficiently strong to hold valve 36 firmly on its seat against fuel pressures in chamber 58 at least equivalent to the gravity head of the fuel supply tanks; otherwise fuel would leak past the main fuel pump, past the fuel control valve II which is maintained in a partially open position by idle spring 89, through the metering unit and into the nozzle chamber 56, creating therein a pressure equivalent to the gravity head and resulting in fuel leakage past valve 36 and into the engine manifold. If the nozzle chamber 5| is vented to atmosphere a substantially constant fuel pressure will obtain in nozzle chamber 55 as well as in metered fuel chamber 81 at all rates of dual flow, except as slightly increased by the build up in the force of spring 42 as the valve opens to accommodate an increase in fuel flow. Such an arrangement, however, requires a fuel pump of higher pressure rating than one in which the nozzle is vented to the Venturi chamber 24.

For purpose of illustration, assume the nozzle chamber 58 is vented to atmosphere and that spring 42 must-be sufficiently strong to withstand a fuel gravity head equivalent to three pounds per square inch. ,A fuel pressure somewhat greater than three pounds per square inch, by the amount of nozzle spring build up, will therefore be required in chamber 58 in order to open the valve wide as for wide open throttle operation. The main fuel pump must therefore have a pressure rating sufficient to overcome all the pressure losses in the system at the greatest rate of fuel flow, including line loss, pressure drop across the control unit valve, pressure drop across the metering orifice, and something over three pounds per square inch for nozzle pressure. At low fuel flows the pump will then be supplying fuel at a pressure greater than required due to decreased line loss, and decreased drop across the metering Jet. This additional pressure is merely expended by throttling across a partially closed slide valve.

If, on the other hand, chamber 58 communicates with Venturi chamber 24, which at wide open throttle may develop a depression of five or more inches of mercury or approximately two and one-half pounds per square inch, a lesser fuel pressure will be required. With this depression existing on one side of diaphragm 39, only a little over one-half pound per square inch fuel pressure is required at wide open throttle to open the discharge valve 38, thereby resulting in a two and one-half pound per square inch saving in the fuel pump pressure required.

A low rates of fuel and air flow very little Venturi depression exists and therefore the fuel pressure in the nozzle need be about three pounds per square inch as before but the fuel pressure as determined for wide open throttle will be more than adequate because the decreased line loss and decreased metering orifice drop more than offsets the increase in pressure required at the nozzle Venturi venting of the nozzle cap therefore permits the use of nozzle shut-off when the englue is not operating without materially increasing the required fuel supply pressure.

Venturi venting has a further advantage in that at closed or partially closed throttle a relatively high pressure exists in the nozzle fuel chamber 58, supply line 53 and metered fuel chamber 81. When the throttle is suddenly opened, the Venturi depression increases very suddenly, thereby opening the nozzle valve 38 and allowing the excess pressure in chamber 58, passage 53 and metered fuel chamber 81 to be suddenly expended, thereby tending to give an immediate increase in fuel flow, which aids appreciably in obtaining rapid engine acceleration in response to a change in throttle opening.

In the modified type of discharge nozzle arrangement shown in Figure 4, I38 is an adapter bar and I32 is a diaphragm type needle valve of similar construction to the valve shown in Figure 2. Fuel under pressure is received from the control unit through passage I53 and acts on diaphragm I39, compressing the spring I42 and opening the valve I38 to allow fuel to flow into fuel passage I49 to be discharged through one or more discharge jets hereinafter described. The air chamber I58 behind the diaphragm I39 may either be vented to atmosphere or to Venturi depression through port I8 I. If desired the port I8I may be connected to a venturi in the air passage to reduce the fuel pump pressure required as previously explained.

The discharge nozzle consists of a hollow cylindrical body member I48 threaded into adapter bar I39 and containing a free fitting fluted piston valve I45 urged against a seat by a compression spring I59 acting between said piston and screw plug I5I. Ports I41 in body I48 enter the nozzle on the adapter bar side of the piston seat, whereas ports I48 enter the nozzle posterior to the piston seat. Ports I41 and I48 can be drilled in the plane of the bar I38 so as to discharge fuel into the lee of the bar obtaining more uniform distribution of fuel in the air conduit as previously described, or can be arranged to best suit the engine requirements.

At low rates of fuel flow, the piston I45 is held against its seat by spring I50 and the entire fuel discharge is through ports I". As the rate of fuel flow increases, the pressure in passage I49 will increase thereby causing piston I45 to move away from its seat and allowing fuel to flow past the piston in flutes I52 and discharge from ports I48. At high rates of flow the piston will move further from its seat thereby completely uncovering ports I48 and eliminating any possible restriction due to flow around said piston.

In the modification of the invention shown in Figures 5 and 6, the primary nozzle assembly consists of body 332, valve 338, diaphragm 339, cap 359, and compression spring 342 which urges valve 338 against its seat in the body member 332. The assembly is fastened and sealed in the adapter 390 by, means of nozzle retaining nut 333, packing 334 and gasket 335. Nut 333 is formed at its discharge end with a venturi shaped internal contour as indicated at 333A. An annular groove 392 is provided in nut 333 which communicates through a plurality of passages 394 with the interior of said nut in the vicinity of the entrance of said venturi. Annular groove 392 also communicates with atmosphere through one or more passages 398.

Valve 338 is formed with an extension 331 terminating in a notched conical tip 338, shown in detail in Figure 6. Fuel under pressure is received at the nozzle through passage 353 from the control unit, whence it flows into chamber 354 and through ports 355 into chamber 358, where it acts on diaphragm 339 causing valve 338 to lift off its seat and allowing fuel to discharge past said seat; excessive opening of said valve being limited by nut 34I striking the stop 359A in the nozzle cap. The vacuum present in the air conduit III, at the inlet to the supercharger and in the vicinity of the discharge nozzle, coupled with the effect of venturi 333A, induces a flow of air from the atmosphere through

passages

398, 392, and 394, through venturi 333A and into the conduit III. The rapidly moving stream of air and fuel flowing through the venturi 333A and striking the notched conical tip 338 results in the fuel being broken up into very small particles.

The quantity of air drawn through the nozzle depends largely upon the differential in pressure between the air entering the passage 398 and the supercharger inlet pressure. The pressure at supercharger inlet is a minimum when the throttle is in a closed position and increases to a value approaching atmospheric pressure as the throttle is opened wide, therefore if the entrance to the passage 888 is at atmospheric pressure the quantity of air flowing through the nozzle is maximum when the throttle is closed, and'minimum when the throttle is wide open. Since the fuel flow is low at closed throttle and high at wide open throttle, better atomization of fuel is obtained at part than at wide open throttle. This arrangement is therefore suitable for use with an engine which is operated a large percentage of the time at small throttle openings.

By connecting nozzle air inlet 398 to the supercharger outlet I3 (Figure 1), a different operating characteristic is obtained. Since the nozzle air outlet is at supercharger inlet pressure, the quantity of air flowing through the nozzle will depend upon the supercharger rise, that is the differential pressure between supercharger outlet and inlet. Since this differential pressure increases as the throttle is opened, the quantity of air flowing through the nozzle will be low at closed throttle and high at wide open throttle, thereby producing better atomization at wide throttle openings and hence being well suited for use with an engine that is customarily operated at, or near, wide open throttle position.

The nozzle cap chamber 358 may be vented either to atmosphere or to the throat of a venturi in the air passage, as indicated at 36I Figures 7 and 8 illustrate a fuel discharge unit positioned posterior to the throttle, not shown, of a downdraft carburetor having side walls 400, between which extends a tubular nozzle 402, having spaced fuel outlet ports 404 in its lateral and under surfaces. The closed ends of the nozzle are seated in recessed retaining nuts 406.

A boss or bar 408 extends transversely across the induction passage, and may be cast integral with the side walls of the carburetor. The boss is formed with a fuel passage 4| which leads from a diaphragm type needle valve of similar construction to the valves shown in Figures 2 and 4. Fuel under pressure is received from the control unit through passage 453 and acts on diaphragm 439, compressing the spring 442 and opening valve 436 to allow fuel to flow into fuel passage M0 to be discharged through discharge jets hereinafter described. The air chamber 458 behind the diaphragm 439 is vented either to atmosphere or to Venturi depression through port 46i.

An idling jet 462 communicates with passage 0 and discharges into the induction passage continuously during the operation of the engine. Preferably, the idling jet leads from the uppermost portion of passage 0 at the point where fuel vapors tends to collect if any are formed during operation of the carburetor. Communication between passage M0 and nozzle 402 is controlled by a valve mechanism which is mounted in a boss 464 secured to the bar 408. The valve mechanism comprises a movable valve member 466 which is urged toward its seat by a spring 468 held in position by a cap 410. Spring 468 is of suflicient strength to hold the valve member 486 on its seat against the pressure of the fuel until the engine speed increases above idling speed, whereupon the increased fuel pressure opens valve member 466 and allows fuel to flow to nozzle 402. With this arrangement, fuel from jet 462 is discharged in a stream or spray at all engine speeds, which provides better atomization and distribution than would be obtained if nozzle 402 were to be used to supply idling fuel, which would drip from the nozzle at several points and would not be adequately atomized. If desired, a bypass 412 of restricted cross section may be provided connecting passage 4" to the nozzle 442, to provide a limited but continuous flow to the nozzle. Such flow will be discharged from the ports 404 in drops rather than in a stream or spray, but will serve to keep th nozzle full of fuel at all times, so that when the throttle is suddenly moved from closed to open position, the rate of fuel discharge from ports 404 will immediately and correspondingly increase, instead of lagging behind the throttle opening movement.

While the invention has been described with particular reference to certain specific embodi- 4 ments thereof, it should not be inferred that the invention is limited thereto or otherwise except in accordance with the terms of the following claims.

We claim:

1. In a carburetor, an induction passage, a throttle controlling the passage, a venturi in the passage anterior to the throttle, a fuel nozzle positioned to discharge into the induction passage posterior to the throttle, means including a fuel conduit for supplying fuel under pressure to the nozzle, a valve in said conduit, and control means for said valve comprising a pressure responsive member connected to the valve and subjected to the pressure of the fuel in the conduit anterior to the valve and to the pressure in said venturi, said fuel and Venturi pressures respectively tending to open and close the valve.

2. The invention defined in claim 1, including in addition means for introducing air into the fuel prior to its discharge from the nozzle.

3. The invention defined in claim 1, including in addition resilient means biasing the valve toward closed position.

4. The invention defined in claim 1, wherein the fuel nozzle comprises an idling jet designed to discharge constantly during operation of the carburetor.

5. In a charge forming device, an induction passage, a fuel nozzle positioned in the central portion of said passage, a member extending from the nozzle transversely of the induction passage, said member having a cross-sectional contour adapted to create a region shielded from direct air flow, discharge orifices in said nozzle positioned to discharge fuel in the immediate lee of said member in a direction substantially at right angles to the direction of air flow through the induction passage, and a closure member responsive to the pressure of the fuel supplied to said nonle for successively closing said orifices upon decrease in the fuel pressure.

6. In a charge forming device, an induction passage, a throttle in the induction passage, a member extending across said induction passage posterior to said throttle, a fuel conduit in said member, a plurality of fuel orifices receiving fuel from said conduit and discharging in the lee of said member, a valve member responsive to fuel pressure for controlling the flow of fuel to said orifices, and a spring pressed popp t valve opening in response to fuel pressure also controlling the flow of fuel to said orifices and adapted to positively cut off the fuel flow to said orifices when the fuel pressure drops below some predetermined minimum pressure.

7. In a charge forming device having an air passage, a fuel nozzle, an air shielding member extending from the nozzle transversely of the air passage, a plurality of discharge orifices in said nozzle spaced longitudinally of the air passage and discharging transversely of the air passage in the immediate lee of said member, means for continuously supplying fuel to said nozzle under pressure, and a pressure responsive closure member adapted to successively close said orifices upon decrease in fuel pressure to thereby vary the number of orifices available for continuous discharge of fuel, said closure member being adaptedto first close the orifices spaced at a greater distance from the shielding member.

8. In a charge forming device having a throttle controlled induction passage. a fuel nozzle having a plurality of longitudinally and circumferentially spaced discharge orifices positioned to discharge into the induction passage posterior to the throttle, means including a control unit and a conduit for continuously supplying fuel to the nozzle under pressure at a rate depending upon the operating conditions of the engine, a closure member responsive to fuel pressure adapted to successively close said orifices upon a decrease in fuel pressure to thereby regulate the number of orifices available for fuel discharge in accordance with the rate of fuel discharge, a valve in said conduit, and means responsive to the pressure of the fuel anterior to said valve for closing said valve when the fuel pressure drops below a predetermined minimum value.

9. In a charge forming device having an induction passage including a throttle and a Venturi anterior thereto, a fuel nozzle having a plurality of fuel outlets positioned to discharge into the induction passage posterior to the throttle, means including a fuel conduit for continuously supplying fuel under pressure to the nozzle, a valve in said conduit, yielding means urging said valve toward closed position, means responsive to the fuel pressure in the conduit anterior to the valve for urging the valve toward open position and to Venturi pressure for urging said valve toward closed position, and a spring loaded piston responsive to variations in the pressure of fuel supplied to the nozzle for successively opening or closing said outlets to thereby vary the number of opened outlets in accordance with variationsin the rate of fuel fiow.

10. In a charge forming device, a. fuel nozzle comprising a body, a cylindrical bore in said body, a plurality of fuel discharge orifices in the body communicating with said bore and spaced longitudinally therealong, a conduit for continuously supplying fuel to said bore under pressure, a spring urged piston slidably received in said bore and responsive to the pressure of the fuel supplied to the bore for controlling said orifices whereby the number of orifices discharging fuel will decrease upon decrease in the fuel pressure, and a valve responsive to fuel pressure controlling said conduit anterior to said nozzle and adapted to positively cut off the fuel fiow to the nozzle when the pressure drops below a predetermined value.

11. In a charge forming device having an induction passage, a bar extending across the induction passage, a fuel conduit within said bar receiving fuel from a source of fuel under superatmospheric pressure, a plurality of fuel discharge orifices receiving fuel from said conduit and discharging in the lee of said bar whereby fuel will be delivered to the air flowing through the'induction passage substantially along the entire length of said bar, a valve in said conduit, control means for said valve comprising a pressure responsive member connected to the valve and subjected to the fuel pressure in said conduit anterior to said valve for controlling the flow of fuel to all of said orifices, and a second valve posterior to the first valve and responsive to fuel pressure for controlling the fiow of fuel to at least a portion of said orifices.

12. In a carburetor, a throttle controlled induction passage, a venturi in said passage anterior to the throttle, a fuel conduit discharging in said passage, a valve controlling the conduit adjacent its outlet in the passage, and a pressure responsive member connected to said valve and subjected to the fuel pressure in said conduit anterior to the valve and to the pressure in said venturi, said fuel and Venturi pressures urging the valve toward open and closed positions respectively.

13. In a carburetor, a throttle controlled induction passage, a venturi in said passage anterior to the throttle, a. fuel conduit discharging in said passage posterior to the throttle, a. valve controlling the conduit, a spring urging the valve toward closed position, and meansv jointly responsive to variations in the pressures in said conduit anterior to the valve and in the venturi for controlling said valve, the pressure in the conduit urging the valve toward open position and the Venturi pressure urging the valve toward closed position.

14. In a charge forming device, an induction passage, a member extending transversely of and across the major portion of the induction passage, a fuel conduit in said member, a fuel nozzle carried by the member intermediate its ends and receiving fuel from the fuel conduit, a plurality of oppositely disposed fuel discharge orifices in the nozzle positioned to discharge fuel transversely of the induction passage in a direction substantially parallel to and in the immediate lee of the member to thereby distribute fuel from the central portion of the induction passage outwardly toward the walls thereof, and. a closure member responsive to the pressure of the fuel supplied to said orifices for successively closing said orifices upon decrease in the fuel pressure.

15. In a carburetor, an induction passage, a throttle therein, a venturi in said passage anterior to the throttle, a fuel conduit leading from a source of fuel and discharging into said passage, a valve for controlling the rate of fuel flow through the conduit, means responsive to the pressure at the venturi for controlling said valve to thereby regulate the quantity of fuel delivered to the passage in accordance with the air fiow therethrough, a second valve in said conduit adjacent its outlet in the passage, and means responsive to the pressure of the fuel in the conduit and to the pressure at the venturi for controlling said second valve to thereby regulate the pressure of the fuel in said conduit in accordance with the pressure at the venturi.

16. In a charge forming device, an induction passage, a throttle therein, a differential pressure creating means in said passage anterior to the throttle, a fuel conduit leading from a source of fuel under pressure to the passage, means responsive to the differential pressures created in said passage and conduit for controlling the quantity of fuel supplied to the passage, a valve in the fuel conduit, and means responsive to the pressure of the fuel in the conduit anterior to the valve for urging the valve open and to a pressure from the differential pressure creating means in the passage for urging the valve closed to thereby regulate the pressure of the fuel in the fuel conduit.

17. The invention defined in claim 11 comprising in addition an idling jet leading from the fuel conduit to the induction passage and designed to discharge constantly during operation of the charge forming device.

18. The invention defined in claim 11, comprising in addition a restricted by-pass around said second valve providing a substantially constant discharge from said nozzle at all engine speeds.

19. In a carburetor for an internal combustion engine, an induction passage, a throttle therein, a venturi in said passage anterior to the throttle, a fuel conduit leading from a source of fuel and discharging in said passage, a metering orifice in the conduit, a valve in the conduit posterior to the orifice, means responsive to the pressure of the fuel in the conduit and to the pressure at the venturi for controlling said valve to thereby regulate the pressure of the fuel in the conduit posterior to said orifice, a second valve in the conduit anterior to said orifice, and means responsive to the pressure of the venturi for controlling said second valve to regulate the pressure 0! the fuel in the conduit anterior to said orifice to thereby regulate the quantity otfuel supplied to the engine.

.FRANK C. MOCK.

EDWARD J. PARTINGTON.