US2034048A - Carburetor - Google Patents

Description

March 17, 1936. w. E. LEIBING ETAL I 2,034,048.

CARBURETOR Filed Sept. 28, 1952 2 Sheets-Sheet 1 iff 45 a! 3mm/m 35 13 if 3342 h//zamLezbmy 2 1 ff A, 1 i905/ey D Fayed.

S25 f1 My March 17, 1936. w. E, LEIBING Er AL CARBURETOR Filed Sept. 28, 1932 2 Sheets-Sheet 2 mim@ /JF 5.@ v m/w, mi@ WH/ Patented ar. l?, 193

CARBURETOR William E. Leibing, Sausalito, and Robley D. Fageol, Oakland, Calif., assgnors to Leibing Automotive Devices, Incorporated, San Francisco, Calif., a corporation of Nevada Application September 28, 1932, Serial No. 635,276

7 Claims.

Our present invention relates to novel carbureting apparatus.

More particularly our invention relates to novel apparatus providing effective fuel carburetion to secure and control mixtures adapted for complete combustion of fuel in internal combustion engines, and by the use of which the efficiency of operation of internal combustion engines when utilizing gasoline and the more volatile fuels is materially increased, while considerably heavier grades of fuel than are at present effectively available may be utilized if desired in the opera.- tion of the usual types of volatile fuel consuming automotive and similar internal combustion engines.

A primary object of the present invention is to provide an improved carburetor for gasoline and the more volatile fuels in which complete atomization of' fuel and the formation of a homogeneous dry gaseous fuel mixture is secured adapted for complete combustion of the fuel mixture when the engine is doing useful work.

While many carbureting arrangements heretofore proposed have been provided with means to prevent the velocity of air passing through the carburetor venturi from passing below a predetermined minimum value; all such prior arrangements have utilized fixed venturi which permit the air velocity to drop materially from the predetermined minimum speed at the fuel jet with resultant loss of atomization of the fuel. Accordingly another object of our invention is the provision of a carbureting arrangement in which the ingoing air speeds at the fuel jet are maintained at a sufficient minimum velocity to secure thorough fuel atomization under all operating oonditons.

As is now well known, when an internal combustion engine is being driven by its load or is operating at speeds substantially above idling speed with the throttle in idling position, incomplete combustion of fuel occurs with resultant discharge of unburned and noxious gases and smoke from the exhaust. Various forms of degassing mechanism have heretofore been devised to operate valves that cut off the fuel `supply to the carburetor jets, or out off the fuel mixture supply for the engine when the engine vacuum exceeds idling vacuum.

Another object of the present invention is to provide an improved and simplified degassing mechanism especially adapted for use with our improved carburetor, but the principles of which are applicable to other carburetors, and which arrests flow of fuel from the fuel jet or nozzle of the mechanism whenever the engine intake vacuum substantially exceeds the idling vacuum without utilization of a special cut-off valve mechanism in the fuel supply or between the carburetor and the engine.

Our improved carbureting apparatus is essentially a cold air carbureting device at low temperatures with the result that when started, engines supplied with fuel therefrom will operate eiiciently without the necessity of being rst warmed up with the engine partially choked as is now necessary. The velocity of the air flowing past the fuel nozzle is primarily relied upon, rather than heat, to secure fuel atomization in our improved apparatus. As a result at the lowengine cranking speeds and when the engine is cold, satisfactory atomization for starting purposes is not secured. Accordingly a further object of the present invention is to provide novel means to supply the engine when cold with a rich thoroughly atomized. fuel mixture at cranking speeds and during cranking only, for startlng purposes whereby the engine is started practically instantaneously and as soon as it is running, is supplied with an effective running mixture, while the starting mixture supply which is excessively rich for running is discontinued, thereby eliminating entirely the necessity for the usual choking operations with the resultant well known disadvantages and ineiliciency due to choking.

We have found by experiment that heavier fuels such as stove distillate, kerosene, furnace Oils, and like low cost nonvolatile fuels may be successfully used in internal combustion engines if they are properly atomized and ifthe engine compression ratios and speeds are properly maintained. Accordingly, it is another object of this invention to devise a carbureting arrangement which can be commercially utilized to take advantage of this discovery. Preferably, the arrangement will be such that different grades of fuel will be automatically selected during operation of the engine.

We have found in practice that the various standard carburetors in use on bus engines are so designed that surges of fuel induced by sudden stops of the vehicle disturb the fuel supply to the jets. In certain types a spurt of raw fuel is induced from the jets which causes waste of fuel and gassing. In other typesthe jets are robbed of idling fuel and cause the engine to stall. Accordingly, a further object of the present invention is the provision of carbureting mechanisms so constructed that the fuel supply to the engine is not disturbed by surges of fuel caused by sudden stops.

In the operation of commercial vehicles driven by internal combustion engines under modern traiiic conditions, it has become desirable to apply speed limiting devices that will not limit the power of the vehicle for accelerating and operating purposes below the governed speed, but will provide a sharp power cut-off at the speed limit. Various forms of mechanical speed governing devices to control the fuel mixture supply to the engine are commercially available, all of which with the exception of the governing device shown in copending application S. N. 614,533 filed May 31, 1932, adversely limit-the power output of the motors to which they are applied below the governed speed. The device shown in said copending application is a highly emcient governor that does not interfere with the power of the engine below governed speeds, and gives a sharp cutoff of power when the speed limit is reached, but may permit a richer fuel mixture than necessary for eiiieient operation at the governed speed to feed into the engine. Without the use of any added mechanism', we are enabled to control the Supply of fuel mixture from our improved carburetor in accordance with engine speed in such manner as to give a reasonably satisfactory gov,

erning action without limitation in power in any way, but without the sharp power cut-off above governed speed secured by the governor disclosed in said copending application. By utilizing our improved mixture governor built into our carburetor with a mechanical governing arrangement giving a sharp power cut-off, and particularly with the governor shown in said copending application, and setting the mixture governor to govern to a speed slightly above and preferably at about R. P. M. above which the mechanical governor is designed to operate, a substantial improvement in eiliciency of the operation of governed engines at governed speeds is secured by assuring operation at governed speeds with a lean efficient mixture and cut-off of fuel at speeds of the vehicle substantially above the governed speeds.

Accordingly another object of the present invention is the provision of novel apparatus of governing the speeds of internal combustion engines.

A further object of the present invention is. to provide novel means operable under changing throttle conditions in a carburetor, to change the fuel mixture ratios in advance of the throttle change, to provide a fairly rich fuel mixture to be delivered to the engine under accelerating conditions, and permitting the most -economical fuel mixture to be utilized at all running positions.

A still further object of our invention is to provide novel apparatus for utilizing heavier fuels than gasoline in conventional spark ignited` Figure 1 is a vertical sectional view of an emaoeaoae 4bodimerit of cur improved carbureting and fuel atomizing device designed for a single fuel.

Figure 2 is a plan View of the form of invention shown in Figure i.

Figure 3 is an end view partially in section of 'the form of invention shown in Figure l..

Figure 4 is a fragmental sectional view taken along line l'V-IV of Figure i. y

Figure 5 is a fragmental sectional view illustrating the -construction utilized to provide our improved mixture governing arrangement.v

Figure 6 is a fragmental sectional view illustrating an embodiment of our invention adapted for the utilization of gasoline or volatile fuel, and stove distillate or a heavy fuel.

Figure 7 is a plan view of the fuel bowl and float chamber utilized in the form of invention shown in Figure 6.

As shown in Figures 1, 2, and 3, our improved carburetor comprises a body casting or housing I to which is removably secured a bowl casting 2, in a, manner that will more fully hereinafter appear, and a top casting 3 secured in place by cap screws ll, forming a separable housing for our improved atomizing and carbureting device. Top casting 3 is provided with a securing flange 5 by means of which the device is connected to the intake manifold of an internal combustion engine throughfthe use of screws that thread into suitable tapped holes 6 formed in securing flange 5, (Figure l).

Fuel is supplied to the device through a connection 1 (Figurei2) threaded into bo'ss 8' of casting I and passes through a suitable lter screen assembly of well known construction (not shown) to a float-operated needle valve assembly 8 of any well known construction threaded into casting I.

Valve assembly 8 comprises a iioat-operated valve member provided with' an operating stem 9 actuated vertically by oat bracket I0. Float bracket I0 is pivoted at one end by means of pin II extending through suitable bearing holes formed in bowl casting 2. Secured to bracket I0 is an annular float member I2 disposed in chamber I3. The .arrangement of the pivot for the float is preferably such that in operation when the brakes are applied to the vehicle the surge of fuel in the float chamber tends to close the float needle valve. Float I2 and valve assembly 8 function in Well knownmanner to maintain a. predetermined fuel level in float chamber I3. Fuel from float chamber I3 passes downward through passage I4 formed in boss I5 of casting 2 and through cross passage I 6, of which one end is closed by a threaded plug II, into annularchamber I8, and through passages I9 and 2| formed in plug 22 to metering bushing 23 screwed into the tapped enlarged end of fuel passage 2I in plug 22. Plug 22 clamps bowl casting 2 in position and'is screwed into the lower tapped end of a tubular well extension 24, of-main casting I, which extends through a. central opening in float I2 and fits snugly into a cylindrical bore of boss I5 so that the lower end thereof forms the upper wall of chamber I8. Bushing 23 is provided with a comparatively large metering passage 25, the necessity for a small orifice being eliminated due to the fact that fuel is fed from float chamber I3 through passage 25 solely under the influence of gravity. A suitable drain plug 2'I is threaded into a tapped drain hole formed in plug 22 for the purpose of draining the oat chamber and fuel passages.

The upper end of passage 25 communicates aosaoaa with an annular chamber 28 formedbetween the upper end of plug 22 and the lower end of tubular fuel well member 29. Communication between chamber` 28 and oat chamber I3 is established through passage 3l closed at one end by screw plug 32, and by means f passage 33 closed by conical fuel metering valve member 34. Valve member 36 is mounted on and actuated by one end of bimetallic strip 35, the other end of which is fastened by screws 3G to a suitable boss 31 formed in bowl 2.

Well member 2S is threaded at its lower end and screwed into the suitably tapped lower end of tubular extension 2t. A screw driver slot 38 is formed in well member 29 to receive a tool when the well member is inserted or removed.

Formed in the tubular well member 29 is a vertical series of lateral passages 39, which establish communication between the well chamber I of tubular member 29 and air slot 82 formed in the exterior of member 29. Communicating with the upper end of slot E2 is annular air channel or chamber 43 which communicates. with main air passage lili of main casting I through passageways #l1 formed in casting I.

Communication between the top of iioat chamber I3 and chamber or passage Bd is established by means of air passage A8, so that a balanced atmospheric pressure is maintained on top of float chamber I3 and over the fuel in well chamber 4I. thereby insuring that fuel flows from the iioat chamber to the fuel well solely under the influence of gravity, and eliminating the necessity for a small metering orifice in member 23, thereby eliminating the tendency present in existing carburetors, of separating complex modern fuels into their constituents, due to forcing the fuel through small metering orifices under heavy pressure differences.

Formed integrally with the upper end of tubular member 29 is a head G9 which nests against a suitably formed conical recess in main casting I. Head 49 is counterbored at 5I to provide a metering valve seat with which metering valve member 52 is adapted to cooperate to vary the opening for the passage of fuel and air mixture out of the top of well chamber @I in accordance with the varying fuel mixture requirements of the engine for which the device is designed. Metering member 52 is formed integrally on the lower end of stem 52 which extends upward through bores 53 and 54 formed in the nozzle supporting tubular extension 55 externally threaded at 56 to receive and adjustably support suitably tapped lower fuel nozzle member 51. The upper end of a helical compression spring 58 nested in a groove 58' of extension 55 engages the upper wall of tapped bore of member 51 to hold member 51 yieldingly in adjusted position. Formed on nozzle member 51 is a worm gear 59 (Figures 1 and 3) which meshes with a worm wheel 60 formed on an operating shaft 6I the ends of which are in suitable bearings (not shown) of casting I and provided at its opposite ends which protrude outward through said bearings with knurled adjusting heads 62.

By rotating heads 62 and shaft 6I, the entire nozzle assembly carried by member 51 may be adjusted with relation to the throttle control member to establish idling adjustment in a manner that will more fully hereinafter appear.

Nozzle member 51 has formed in'egrally therewith threaded nozzle tip member pilot extension 63 upon which the nozzle tip member 64 is screwed. Nozzle members 51 and 64 are provided respectively with conical surfaces 55 and 56 spaced apart to form a fuel mixture outlet channel from the nozzle assembly through which a conical sheet of fuel mixture or air fuel emulsion is fed into the air stream drawn through the carburetor in a manner that will more fully hereinafter appear. The separation of surfaces 55 and 66 may be varied by adjusting tip member 53 on threaded supporting shank 53.

The spacing or separation of surfaces 55 and or channel formed thereby form important features of the present invention. The spacing arrangements should be such thata rolling turbulence or intimate mixing effect occurs on the fuel as it passes between surfaces 65 ,and 58, and a directional effect is imparted to the fuel mixture flowing from the nozzle in operation, so that a conical sheet of fuel mixture in the form of an intimate mixture or emulsion of air and fuel is fed substantially at right angles into the air stream passing the nozzle assembly. A passage length of approximately three-eighths of an inch, and a thickness of 0.005 to 0.012 of an inch have given excellent results in practice in a carburetor utilized on a La Salle car, the preferred spacing being approximately 0.010 of an inch.

The fuel passages formed between surfaces 85 and 56 terminate in an annular distribution.

chamber 61 connected by passages 68 formed in the base of threaded extension 63, to' chamber 38 formed in extension 53, and which communicates with the upper end of bore 5ft of tubular extension 55. The opening between chamber 69 and bore 515 is controlled by the position of metering valve member Il formed integrally with stem 52'. Member 1I is formed integrally with a stem 'I2 the upper end of which is reduced in diameter and extends through and is secured to boss 13 by means of nut 15. Boss 13 is rigidly secured by means of ribs 15 (Figure 2) to lower half I6 (Figure 1) of a control tube assembly.

Air passing by the nozzle is drawn through the usual air cleaner into passage #l5 and the flo'w past the nozzle assembly is controlled by control tube assembly having a control passage 11. The control tube assembly is provided with l86 and the length of the fuel ejecting passage an upper manually controlled section 18 having a cylindrical surface 19 which fits slidably into bore 8| of upper housing casting 3. Formed integrally with section 18 is an annular shouldered section which serves as a stop for the upward vertical movement of section 18, and spaced therefrom and forming annular groove 83 is cylindrical skirt piston 86 which fits slidably into bore 85 of top casting 3. The upper cylindrical end section 16 ,fits slidably in a complementa] shouldered central bore formed in section 18. Formed integrally with control tube section 16 is a cylindrical or trunk piston extension 86 which ts slidably in a bushing 86 pressed in a bore formed in housing section I. Communication between the engine side of the nozzle assembly in paage 11 and the spacebetween pistons 84 and piston 86 is established by means of passages 81 to establish engine manifold pressures between the pistons in operation. A spring 88 interposed between pistons 84 and 85 normally tends to separate the pistons and control tube assembly sections 16 and 18 with a light pressure so that a predetermined velocity of air, sufficient to maintain complete atomization is necessaryvto compress spring 88 sufliciently to bring sections 16 and 18 together. For the atomization of fuels such as gasoline a spring that requires about one inch vacuum between the pistons Sli and il@ to bring sections 1t and 19 together when section i8 has been moved to its upper or wide open position has been found sufcient to maintain atomization under all conditions of operation, in the manner that will more fully hereinafter appear, while for heavier fuels such as stove distillate a spring requiring a two inch vacuum between the pistons to bring the control sections 1t and 18 together has been found satisfactory. The stiffness of spring S, it is to be understood, will be varied for dierent fuels and with different engines to maintain atomization when control section is moved suddenly to open position, as frequently happens in operation. The strength of spring 88 is, however, by no means critical, as a wide range of spring strength will give satisfactory operation. The position of control tube 18 with relation to nozzle assembly in operation of the device is controlled by means of hardened curved actuating members 89 (Figures 1 and 4) which fit into annular groove 83. Members 88 are formed integrally with arms 9| of yoke 92, which is rigidly secured to operating spindle 93 suitably journalled for rotation in bo'sses 94 of casting 3. Any suitable actuating mechanism may be provided for rotating spindle 93 as for example arm 95 secured at one end to a projecting end of the spindle and provided at its other end with arcuate toothed rack 98 meshing with pinion 91 rigidly secured to operating arm 98 which is journalled on spindle 99. Operation of arm 98 results in vertical displacement of the tube 16 with respect to the nozzle assembly in a manner that is apparent to those skilled in the art.

Proper proportions of spring 88 and the shape and arrangement of passage 11 which extends through control tube sections 16 and 18 with respect to the fuel nozzle are important to secure complete atomization of the fuel mixture throughout the range of operation of the device. The strength of spring 88 should be selected as pointed out to maintain atomizing velocities for the particular fuel used when section 18 is moved to open position suddenly, and passage 11 should be shaped and proportioned with respect to the fuel nozzle assembly so that in all conditions of operation a suiiiciently high velocity of flow of air through passage 11 will be maintained for a sufficient length of time to cause sufficiently fine division of fuel particles fed into the air stream from the nozzle so that they will remain in suspension for substantial periods even when the velocity of flow is arrested or suddenly reversed in an engine manifold. If the requisite velocity is not maintained for a sufficient distance, a wet fuel mixture results from which the fuel will settle or be thrown out in the intake manifold, more or less of lthe type of mixture produced by prior carburetion systems, so that heat must be applied to the manifold to secure a proper combuston of mixture in the engine.

The relationship of velocity and distance of iiow necessary toproduc my novel dry gas fuel mixture suitable for cold air carburetion varies with the size of the carburetor utilized, depends upon the nature of fuel and degree of volatility of the nozzle design and other engineering factors, since the establishment of an excess velocity and length of flow over the minimum values required is beneficial as the higher velocities and lengths of fiow are reculired for the heavier fuels, and a carburetor designed to produce my improved dry gas mixture with a heavier fuel, will function properly with the lighter fuels. so that absents by designing the carburetors properly, a wide range of fuels may be utilized in a given motor vehicle.

Furthermore, since 'the velocity oi. air now through passage il is decreased as the throttle opening is increased, and is at a minimum at the widest throttle opening, by designing the control tube so that sufficient velocity and length of ow exists with the throttle or control tube l1 in wide open position to secure Complete atomization, desirable fine division or atomization of fuel will be secured throughout the entire range of operation of the carburetor from wide open to idling condition. It is to be here noted that the arrangement whereby an intimate mixture or emulsion of air and fuel is fed from the nozzle into the air stream in control passage 11 is an important aid in securing atomization or apparently colloidal division of fuel particles, particularly of the heavier fuels utilized, apparently due to the sudden expansion of the intimately mixed air las the mixture leaves the nozzle. The specific shape and proportions of controlpassage 11 and the nozzle for a La Salle pleasure car are given in detail in copending application Serial Number 543,427, which has matured to Patent No. 1,990,702 granted Feb. 12, 1935.

Under normal operating conditions, the effect of spring 88 is overcome and sections 1B and 18 of the control tube assembly are held together by the eiect of the velocity of air flowing through passage 11 of the tube assembly, and the throttle opening past the nozzle assembly is determined by the vertical position of the accelerator tube section 16. The positions of metering members 52 and 1I, which determine the richness of the fuel mixture, it will be noted, will be determined by the position of control tube 16 for the purpose of varying the relative proportions of fuel and air fed to the fuel nozzle for various throttle positions, thereby varying the richness of the Afuel mixture to meet the varying engine requirements at different throttle openings and under varying load conditions. Since the maximum velocity of air flow in passage 11 occurs while control tube 16 is in its position o'f minimum opening or idling position, and the minimum velocity of flow occurs past the fuel outlet with the control tube in wide open throttle position, the maximum suction effect on the nozzle occurs in idling position. However, with control tube 16 in idling position it will be seen that valves 52 and 1| are in their lowermost positions establishing a minimum area for fuel mixture passage fromwell 4| to the nozzle. On the other hand, with the throttle in wide open position valves 52 and 1I are in their uppermost positions permitting a maximum iiow of fuel mixture to the nozzle from the well.

In operation at idling speeds, idling intake vacuum exists above member 12 and the parts are so adjusted that about one-half inch of vacuum exists between members 52 and 1|, the two metering members being provided to give more accurate control of the fuel mixture than can be secured with a single metering member.

When the accelerator is operated suddenly to impart an opening movement to the accelerator section 18 of the control tube assembly, section '16 which rides the air stream past the nozzle assembly lwill lag behind section 18, under the influence of spring 88 and will restrict the opening around the nozzle assembly sufliciently to maintain an atomizing velocity of the air stream past the nozzle until the engine accelerates to the point Where the effect of the air stream on section 1B is suilicient to overcome spring 88 and to raise section 16 into collapsed position with relation to section 18. When sumcient air velocity is present to overcome spring 88 and hold tube sections 1B and 18 together, the air velocity past the nozzle assembly is always sufiicient to maintain atomization of the fuel. In this way it will be seen that the minimum ingoing velocity of air at the fuel jet or nozzle is sufficient under all operating conditions to maintain fuel atomization.

To secure idling speed adjustment, the vertical position of the nozzle assembly is adjusted with relation to the control tube assembly by means of adjusting heads 62 as above pointed out. To secure idling mixture adjustment an air inlet opening ||i| is provided between metering control members 52 and 'Il in tubular extension 55 which is controlled by the conical end of idling adjusting valve member |02 (Figure 3). Valve member I G2 is adjustably supported on a suitably threaded section ||i3 in a tapped hole formed in main casting I, and is held in adjusted position by a spring IM which abuts against knurled adjusting head thereof. By adjusting the position of valve member |02 the amount of air leakage from passage may be varied to vary the richness of the idling mixture drawn through chamber 5d from the fuel well.

A built in fuel economizer and gas eliminating mechanism is preferably provided, operative when the control tube assembly is in idling position and the engine intake pressures in Passage 11 on the engine side of nozzle assembly drop below normal idling pressure, to cut off the fuel mixture flow to the nozzle thus materially increasing the efciency of the engine supplied with fuel by our improved carbureting devices, and eliminating the discharge of noxious gases and unburned fuel that normally occur when the load is driving an internal combustion engine. It will, however, be understoodV by those skilled in the art that the built in economizer may be eliminated if desired as the carburetingl mechanism so far described is operative without our built in economizer.

As shown in Figure l, an opening I|| is provided between metering members 52 and 1| into which funnel member ||2 is pressed. A perforated guide member I I3 is secured in funnel I I2 bored centrally to slidably receive valve guide extension H4.

Guide extension II 4 is provided with a collar section I|5 and a threaded extension II 6 which is threaded into the metallic wall ||1 of resilient metallic bellows member I8 and into base II9 of a tubular central guide member |2| for the bellows. A fibre valve member |22 for the mouth of funnel member |I2 is clamped in position between bellows wall II1 and collar I I5. Extending slidably into tubular guide member |2I is a guide pin |23 one end of which is rigidly secured in adjusting screw plug |24 provided with a screw driver slot |25 for adjusting purposes. Mounted on guide pin |23 for relative rotation is a spring thrust member I 26 which abuts against anti-friction balls |21 mounted in a suitable groove formed in the end of screw plug |25. A compression spring |28 interposed between thrust member I 26, and wall |I1 of the resilient bellows IIB surrounds tube |2I and guide pin |23, and resists the tendency of bellows I|8 to retract valve I 22 in operation in a manner that will more fully hereinafter appear.

Screw plug |26 is threaded into the tapped end of tubular member |29 and is locked in position by means of the threaded locking collar |3I. Tubular member |29 is provided with a flanged nut section |32, and threaded plug section |33 which screws into the tapped section I3@ of casting I in which the bellows assembly is mounted. Bellows IIB is rigidly secured to the inner end of plug |33 by soldering or in any other suitable manner.

Communication with the interior of plug member |33 and the interior of the bellows is established through passages |35 to an annular chamber |36 formed by means of an annular groove cut into plug |33. Communication from chamber |36 is established through passages |31 and I3@ in main casting, I to the space between pistons Si and 8S of the control tube assembly, which in turn is connected to the engine side of the nozzle assembly, so that engine intake manifold pressures are established at all times in the interior of bellows I i8, and so that when the intake pressures on the engine side of the control tube assembly go below normal idling pressures bellows Iiii will contract and will unseat valve |22 from funnel |I2 permitting a large volume of air at atmospheric pressure from passage @t to enter chamber 53 between metering valve members 52 and 1I.

When the engine is idling or is doing useful work, the engine intake pressures will be equal to or above normal idling pressures, and under such conditions the parts will remain in the position shown in Figure 1. When, however, the load drives the engine with the control tube assembly in idiing position, as for example during deceleration of the engine, the pressure in passage 11 on the engine side of the nozzle drops below the normal idling intake manifold pressure, and the proportion and adjustment of parts is such that tendency of bellows I I8 to contract will overcome the compression of spring |28 sufciently to unseat valve face |22, and the resultant air ow through funnel II24 into chamber 53 will cut 0E the fuel supply completely from the nozzle, and air will be drawn from chamber 53 to the nozzle.

In operation the nozzle assembly is adjusted with relation to control tube assembly' and valve member |02 is adjusted in the manner above set forth to establish a proper opening and fuel mixture for idling purposes. Plug |24 is adjusted with control tube assembly in idling position so that the compression of spring |28 will just overcome the tendency of bellows IIB to contract and valve member |22 will be held against and will seal the mouth of funnel member I I2. When the pressure in the control passage 11 on the engine side reaches normal idling pressure bellows IIB again expands, and with the control tube in idling position valve |22 will be seated against 'the end of funnel II2 and idling fuel mixture will again ilow to the nozzle assembly from well tI with no perceptible lag in the fuel supply.

In addition to the variation of the proportions of air and fuel secured by operation of valves 52 and 1| with the position of the throttle and movement of the control tube assembly, the relative proportions of air and fuel are varied automatically in accordance with variations of the engine in given throttle positions by the arrangement shown.

With the engine turning over at high speed in any given throttle position a balance of fuel levei in well 47| will be established which will result in a predetermined amount of air being drawn through openings 53 in the well tube 25 and mixed with the fuel passing upward into chamber 53. If the engine slows down with the throttle in the same position, due for example to an increase in grade or other road conditions met by the vehicle, the suction eifect of' the engine on the carburetor will be reduced, and the fuei level in well i|| will rise reducing the number of holes 39 through which the air may pass into chamber iii A larger proportion of fuel and less air will accordingly be drawn from well 5|, with the result that a richer fuel mixture will be supplied to the nozzle to assist the engine in carrying the increased load, and a new position of fuel level and balance will be established in the well li.

As the load on the engine decreases, as for example, when a vehicle reaches the top of a grade, the engine speeds up, an increased volume of air will be drawn through the carburetor increasing the .velocity of flow past the fuel nozzle and as a result increasing the suction on well 5|. the increased suction on well 3| will result in a lowering of the fuel level until a new balance is established.

In this way it will be seen that the fuel mixture supplied to the nozzle is varied in richness in accordance with throttle position as well as engine speed, and all fuel is cut o during deceleration, providing highly efiicient operation and most eective fuel mixtures throughout the entire operation of the engine.

By substituting for the well member 29, a member of the construction illustrated in Figure 5, in which the vertical series of air inlets 39 extend downward from the top of the member Z5 a distance corresponding to the level in well 5| to which the fuel drops when the engine is operated at a speed at which it is desired to eifect governing, and at this level adding a horizontal series of air holes |40. When the fuel in the well reaches the level of the holes |40 an excess volume of air will be taken into Well M through holes |56, and only sufficient fuel mixture will be supplied to the nozzle assembly to drive the engine at the speed determined by the level of holes |60. The maximum engine speed will accordingly be held to a. denite predetermined value. In this way an effective governing action is secured which, while not as sharp as that secured by the mechanical governor disclosed said copending application, is satisfactory for certain commercial purposes.

When our improved carburetor is used in cornbination with a mechanical governor of the type shown in said copending application set to operatc at a speed slightly below the maximum speed permitted by utilization of the governing ar rangement illustrated in Figure 5 a very emcient governing action is secured with lean mixtures at the governed speeds, making a highly desirable combination where sharp governing ofthe engine speeds to a predetermined mammum speed Without loss of power and efciency is desired.

While the usual methods of choking our improved carburetor by restricting the amount of air entering into well [7| through openings 157 as illustrated in said copending application S. N. 543,427 may be utilized for starting purposes as will be apparent to those skilled in the art, our invention comprises the improved mechanism and methods now to be described in detail, by means of which a thoroughly atomized fuel mixture is aosaoee supplied to the engine at cranking speeds when the engine is cold.

To incorporate our improved starting device in the form of invention shown in Figure l, the starting mixture is fed through duct or passage |l|| formed in casting to the space between the control tube assembly pistons 8d and 86 and passes through the openings 87 into control tube passage 77 above the fuel nozzle assembly. The outer end of passage |4| is closed by a screw plug |52, and passage |li| vcommunicates with a chamber |53 through opening |44 which is controlled by valve member |45. One end of passage !63 is closed by a screw plug |136 and the other end communicates with air intake passage it through opening |67. Located .in chamber |535 between valve |55 and the atmospheric opening |57 is a small Venturi tube |58 provided adjacent its throat with an externalfuel groove |49 which communicates through a series of small openings |56 with the Venturi throat. Commu- `nication between annular exterior groove |179 of tube |618 with the fuel in float chamber is established through a small tube |52.

Valve |55 is guided for vertical motion in a solenoid supporting member |53, preferably of non-magnetic metal, which is threaded into a suitable bore formed in main casting i. The upper end of valve member |||5 is provided with a grooved section |54 into which suitable securing prongs of the solenoid plunger |55 of magnetic material fit so that lvalve member |45 is actuated by the solenoid plunger |55. Solenoid plunger |55 is slidably mounted in a. tubular extension of supporting member |53, and is normally urged downward by the action of compression spring '|56, the lower portion of which nests in and abuts against a. shoulder bore formed in plunger 55, and the upper end of which abuts against a screw plug |57 provided with a guide extension projecting into the upper end of the spring |56, and which is threaded into and closes the upper end of the solenoid receiving bore in i supporting member |53. Supported by and surrounding member |53 is a solenoid coil |58, one terminal of which is grounded, and the other terminal of which is connected by a wire |59.to the end of a bi-metallic thermostatic contact spring member |6| secured by screws |62 to a suitable ber insulating block |63. Block |63 is secured to the top plate member |65 by screw |66 or in any other suitable manner. Contact spring |6| carries and actuates a contact |67 (Figure 2) which is adapted to engage a contact |68 carried by a fiber block |63. Contact |68 is connected by a suitable conductor to the binding post |69 on block |63. Suitable covers 77| and |72 for the contacts and solenoid coil are provided. Binding post |69 in operation is connected by suitable conductor |73 to the motor vehicle starter contact |75. A lead |75 from contact |75 is connected in series with the engine starting motor. Contact 71| is connected by means of the spring contact |76 and the usual starter button |77 located on the oor board |73 of the vehicle, to battery |79 which is grounded at |8|.

In operation, when the carburetor is cold, bimetallic contact strip |6| operates to hold contact |57 and |58 in engagement completing a circuit from contact |74 through coil |58 to ground. When the carburetor is warmy with the engine heated contacts |67 and |68 are separated by expansion of spring |6| and solenoid |58 can not be energized.

With the carburetor cold and contacts |67 and |68 closed when starter button |11 is depressed,

the starting motor will be energized from battery |19 through lead |15 and the solenoid |58 will simultaneously be energized through the circuit completed by lead |13 and closed contacts |61 and |68. Energization of the solenoid coil |58 Will result in raising of plunger |55 againstl the compression of spring |56, and will raise Valve member opening passage |44 to establish communication from the engine manifold through passage control tube openings 81, the space between pistons 84 and 86 and duct I4I. With the control tube assembly in closed throttle position, cranking the engine at comparatively low speeds will induce a substantial suction in passages I4l,4k

and |44, and will draw air at high velocity through the small opening |41 and the interior of venturi |48. The velocity of the air passing through venturi |48 is increased in well known manner at the throat of the venturi, with the result that a substantial suction is created through the opening I5I on annular chamber |49 which results in drawing fuel through tube |52 from the interior of the carburetor bowl I3. The fuel drawn up through tube |52 into the venturi |48 through openings I5I, is thoroughly atomized due to the high velocity of air passing through the Venturi section, and a Very rich atomized fuel mixture is drawn through passages |44, I4| and 81 into the passage 11 where it mingles with the idling air and supplies a very rich, thoroughly atomized starting mixture to the engine.

The starter button |11 is released upon starts ing of the engine, the circuit to solenoid |58 is then broken at contacts |14 and |16 and spring becomes operative to force solenoid |55 Vand valve |45 downward closing opening |44 and cut- -ting off the fuel mixture supply and air ilow through venturi |48. The engine which Will then be operating at idling speeds, will then receive a proper supply of fuel mixture for operating purposes from the fuel nozzle assembly.

The supply of fuel to the nozzle assembly is augmented while the carburetor is cold and warming up by operation of the thermostatically controlled valve Y34, which is in open position when the carburetor is cold, permitting fuel to enter well 4I through supplemental passages 28 and 3|. As the engine heats up, valve 34 is gradually closed reducing the fuel supply through the passages 28 and 3|, and when the engine is heated to proper running temperatures valve 34 is completely closed. The fuel supplied from the carburetor then passes into Well 4| entirely through the metering bushing 23 until the carburetor again becomes cold enough to cause opening of valve 34, when additional fuel is supplied in the manner above set forth. So long as the engine temperature is suicient for satisfactory starting and operation with the normal fuel supply from the nozzle assembly, contacts |61 and |68 will remain open and valve 34 will remain closed.

Our improved starting mechanism, operative when the engine is cold, is highly effective and assures proper mixtures for starting at cranking speeds, and eliminates the necessity for choking completely, with the resultant elimination of crank case dilution, other disadvantages, and fuel Waste incident to the choking necessary with the conventional types of existing carburetors.

'I'he detailed operation of the various sub-combinations of parts of the device shown in Figures 1 to 3 having been hereinbefore described, a genoat chamber I3 by operation of the float controlled valve assembly 8 and fuel flows from chamber |3 through metering orifice 23 at a rate determined by the difference in fuel level in well 4| and in chamber I3. Owing to the fact that substantially equal atmospheric pressures are maintained on the fuel float chamber and in well 4| through communication with passage 44, the flow of fuel to well 4| is under the sole influence of gravity, and the rate of ow is determined by the rate of fuel consumption.

The positions of lvalves 52 and 1| determine the relative amount of fuel and a ir passing from well 4| to the fuel nozzle assembly. Since the positions of valves 52 and 1| are determined by the throttle position in normal operation, the richness ofthe mixture will be dependent upon the throttle position as well as the speed of operation of the engine as hereinbefore set forth in detail. Fuel vapors passing from the float chamber will be drawn into passage 11 from passage 44. The proper fuelsupply for each given engine condition, in passing through chambers 4|,

' 53 and 69 and out of the fuel outlet, is intimately mixed with the air and reduced to a state of an emulsion of fuel and air, the final mixing occurring in passing out through the fuel passages between surfaces65 and 66 of the nozzle.

Air drawn through the usual -cleaner and through intake passages 44 by the suction of the engine ows past the nozzle into control passage 11, and because of the pressure difference between the atmospheric side and the engine side of the fuel nozzle, passes the nozzle at high velocity throughout the entire range of the control tube positions from idling to wide open position. At wide open position in which the velocity of flow past the nozzle is lowest, due to the shapeof passage 11 the velocity of fio-W is increased for a substantial distance beyond the nozzle outlet. Due to the circumferential length of the fuel nozzle and the comparatively small space between the walls of passage 11 and the edge of the fuel nozzle outlet, a very intimate contact of the ingoing air streams with the fuel emulsion emitted from the nozzle outlet is secured. This results in minute particles or ribbons of fuel being torn from the fuel mixture or emulsion being project.- ed from the fuel nozzle at approximately right angles to the air stream due to the comparatively lower pressures in passage 11 during operation.

As the particles of fuel emulsion leave the fuel nozzle and enter the air stream, the airin the emulsion expands due to the lower pressures outside of the nozzle tending. to atomize the fuel, and

the particles are caught in the air. stream and operating positions of tube 16 for a sufficient distance to reduce the particles of fuel to a suiiifciently line division so they Will remain suspended in the air, forming what appears to be a suspensionof colloidally divided fuel in air. 'I'he fuel mixture produced in this way is a homogeneous dry gaseous mixture of fuel suspended in air in a form that will give effective uniform and complete combustion in the cylinder of an engine Without development of detonating pressures.

With the fuel well 4| centrally arranged in circular float chamber I3 and iicat I2 supported in such manner that with the mechanism in position on a vehicle, sudden stopping of the vehicle causes the resultant fuel surge to actuate float I2 to close, needle valve 9, the level of fuel in the float chamber is not altered due to excess fuel admission during surges as occurs in the Various carburetors at present o n the market, and the effect of fuel surges in float centrally arranged' chamber on the supply of fuel to well 0| is negligible, giving a considerably improved operation for motor vehicles with our improved carbureting apparatus, due to the effect of elimination of sudden surges on the fuel supply.

The forms of invention so far described are designed for the carburetion of a single fuel. By

changing the construction of the oat chamberI and fuel well to provide a modified multiple oat chamber and fuel control arrangement as illustrated in Figures 6 and '7, our invention may be arranged to supply a volatile fuel mixture for starting, idling and acceleration purposes, and for operation below the speeds and compressions where lower grade fuels such as distillates, alcohol and the like may be effectively consumed in the engine, and at engine compressions and speeds suiiicient to effectively burn a heavier fuel supplying a suitable heavier lower cost fuel. The nature of the fuel mixture supplied to the engine is determined automatically by our improved device in accordance with the engine compression and speeds.

In Figures 6 and 7, parts similar to those heretofore illustrated and described in detail in connection with Figures l to 4, inclusive have been given like reference characters and the description thereof will not be repeated as reference may be had to the foregoing description for a full understanding thereof. In this form of invention, the casting 2 is divided by dividing wall |9I and central tubular section I5 which extend to the top of the bowl casting into the gasoline chamber I3 and a heavy fuel or distillate chamber |92. Gasoline controlling float I2 is semi-annular in form, and bi-metallic thermostatic strip 35 which operates the conical valve is fastened to boss 3l on the bottom of chamber I3. A distillate oat |93 similar in construction to the gasoline oat I2 is supported from pin; II by the bracket I0 which operates a needle valve 9 of a oat Valve assembly 8 similar to the gasoline float assembly heretofore described to maintain a predetermined level of distillate in chamber |92, as will 'be obvious to those skilled in the art. 'I'he float pivots and chambers are so disposed that with the car- .buretor in position on a vehicle engine fuel surges caused by sudden vehicle stops close valve 9 and such surges have no effect on the floathamber fuel level or on the fuel supply to the jet in operation, a novel feature of our invention.

Gasoline chamber 3 is connected by gasoline by-pass passage 3| which is controlled by valve 30, to annular chamber 28 at` the base of the tubular fuel ymember 29, from which gasoline passes through openings |94 into well chamber 0I, so long as the carburetor is cold and until valve 30 has been closed by the action of the thermostatic strip in the manner hereinbefore set forth in detail. Metering stem 52' is provided with bore I 95 in its lowcr end in which spring |96 is nested, the lower end of which abuts against head |91 of a fuel controlling valve stem |99 which extends slidably through a, central bore formed in metering valve member 52. These parts are held in assembled relation by the metering member 52, which is provided with a threaded shank screwed into the tapped lower end of bore |95. Fuel valve operating rod |98 extends centrally downward through well member 29 and gasoline chamber I9 which chamber communicates with the gasoline oat chamber I3 through passage I in a manner hereinbefore set aosaoss forth. The lower end of stem |90 engages the central portion of perforated web |99 of cylindrical fuel control valve 200. Fuel control valve 200 is slidably mounted in a cylindrical bore formed in the threaded shank cf screw plug 20| and is urged upward so that it engages the lower end of rod |90 by a helical compression spring 202, disposed within the lower cylindrical section of Valve 200 and nested in the bore of plug member 20|. Plug member 20| is screwed into the lower tapped end of tubular extension 24 of main casting below well member 29 and clamps the bowl casting 2 in position. A drain opening 203 is,A provided in the bottom of plug 20| which is closed by drain plug 205 and by the removal of which the oat chambers |3 and |92 may be drained.

Cylindrical valve 200 in its lowermost position is arranged to cover annular chamber 206 which communicates through openings 20`| with annular chamber 208 formed at the base of tubular extension 20 of main casting I. Chamber 208 is connected by means of distillate inlet passage 209, (Figure 7) to distillate chamber I 92. In its lowermost position valve 200 therefore cuts off the flowv of distillate from chamber |92 to well 13|, and in its uppermost position, the upper edge of valve 200 is adapted to nest in cylindrical recess I9 formed in the bottom of well member 29 to cut oi communication between the gasoline chamber I9 formed at the base of well member 29 and the interior of well 0| `In the intermediate positions of the control tube and metering member 52, varying proportions of distillate and fuel will be permitted to pass from chambers I3 and |92 through chambers I9 and 203 into well 0I providing a fuel mixture, dependent upon the position of lower section 'i6 of the control tube assembly.

The remaining parts of the dual fuel carburetor illustrated in Figures 6` and '7 including the fuel nozzle divided control tube, starting arrangement and other essential parts, not shown, and the operation thereof are the same as illustrated and described in connection with Figures 1 to 5 inclusive.

Spring |95 acting on head l 91 is stronger than the spring 202 acting on two way-valve 200 and consequently by proper arrangement and proportion of parts two way valve 200 can be held against the lower seat for any period of movement of metering pin 52 and the lower control tube section 16. If desired, metering pin 52 can be permitted to move upward one fourth or more of its total movement corresponding to one quarter opening or more of the carburetor and duringy this movement two way valve 200 may be held against its lower seat permitting ronly gasoline to flow. After such movement, a further comparatively slight opening movement of the lower throttle section disposes valve 20!! between both valve seats permitting fuel to enter well 0I from both float chambers, and a further slight opening movement of the lower throttle section closes the valve against the top seat and leaves the lower valve opening fully open, cutting off the gasoline supply and permitting only heavier fuel from chamber |92 to pass to well ll and the fuel nozzle.

Under wide open throttle conditions, the lower control tube section together with stem 52' and metering member 52 are velocity controlled only since the lower tube section I6 is not mechanically fast to upper section, but merely rides the air stream with spring 88 opposing the air stream, so that under and at low speeds with wide open Cil acerbes throttle, the lower control tube section it is depressed by spring 88 and where the speeds are sufhciently low, will operate two way valve 26B with :no movement of the accelerator controlled throttle tube section l. Such conditions exist during acceleration, on hills and at any low speed under wide open accelerator and throttle condim tions. Therefore, in operation, valve 2li@ may be mechanically forced down by .the action of closing the throttle, but it cannot be mechanically forced open by any other means than velocity of ingoing air.

Accordingly, with our carburetor installed on a vehicle engine operating at idling speed, the con trol tube assembly is forced downward by the controlling accelerator and metering pin 52 is forced to its lowermost position restricting fuel mixture how to the nozzle to a minimum, while valve 2li@ is held down against its lower seat, and all ow of distillate from chamber m2 is therefore cut 0E, while gasoline flows freely to the well pastthe open upper seat of valve 2M. The engine is therefore idling on gasoline or volatile fuel only from chamber iii.

As the throttle is opened, the control tube assembly and metering member 52 move up slightly as the engine speed picks up but the spring arrangement acting on Valve 2%@ is such that it remains against its lower seat. The engine will gain in speed with the throttle opening but the proportioning of parts is such that it will be supplied entirely with gasoline until the engine speed and compressionhas been built up to a pointwhere a heavier grade of fuel can be effectively utilized by the engine. VAfter this point is reached as the throttle opens still further, two way valve Elli) moves upward with throttle and distillate from chamber HB2 will be admitted to Well dl while the relative quantity of gasoline or volatile fuel admitted thereto from chamber i3 will be decreased. Small movements either way change the fuel ratio accordingly fed to well l from chambers I3 and |92, an important feature of our invention. When the use of distillate is started a small quantity only is used, and a gradually blended change-over from one fuel to the other is secured, so that at the higher speeds and compressions where the engine can operate effectively on distillate or the heavier fuel, only the heavier fuel will be supplied. As the throttle is either gradually or quickly closed the order of operation of valve 20G above given is reversed and a correct fuel mixture to meet the engine requirements at different speeds and compression ratios is supplied.

Also with wide open throttle and low engine speed, the position of the lower control tube section 'i6 is controlled by the velocity of the ingoing air and spring 8B with no motion of the accelerator itself, and the fuel mixture is properly proportioned for engine operating conditions automatically in accordance with engine speeds and compression which determine the velocity of the ingoing air through the control tube assembly. Therefore, when during acceleration or hill work the speed falls below a predetermined value, spring operating lower control tube section 16 partially closes the throttle opening at the nozzle, and the mixture of fuel changed from straight distillate or heavier fuel to a suitable ratio of heavy fuel and gasoline, and under severe conditions cuts oi the heavy fuel entirely, and only gasoline is supplied to the engine until the speed picks up. 'Ihe operation is therefore entirely automatic and correct fuel mixtures for the engine requirements are sup/plied with no need for manual control.

if it is desired to utilize heavier fuels than can be emciently burned in the engine, or to assure that such heavier fuels will be burned effectively in view of the wide variation of such commercial fuels, valve 206 may be constructed so that in its fully closed position it will permit a suihcient supply of gasoline to flow to well lll to supply a propm er operating mixture of the lowest grade fuel that may in practice be fed to chamber ld.

Having described preferred embodiments of our invention, only, it will be apparent to those skilled in the art that our invention may be em bodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indig cated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What we claim and desire to secure by United States Letters Patent iszl. In a carburetor for an internal combustion engine, a fuel supply chamber provided with inlet and outlet openings; tandem metering pins controlling said inlet and outlet openings respectively; means for admitting a variable air supply to said chamber between said metering pins to vary the richness of the engine idling fuel mixture supply; and means for establishing atmospheric pressure between said tandem metering pins whenever the pressure on engine side of carburetor goes below engine idling pressures.

2. A carburetor comprising a mixing chamber in the form of a venturi, having a movable throat section, a fuel nozzle coaxially alined with said venturi and forming together with said throat section a throttle, one end of said venturi having an outlet adapted to be subjected to the intake vacuum of an internal combustion engine and an air inlet open to the atmosphere whereby said throat section is subjected to a draft of air tending to move it away from said nozzle, means operable to prevent said throat section from moving away from said nozzle, and resilient means between said iirst mentioned operable means and said throat section whereby when said operable means is operated the force exerted on said throat section by said resilient means is reduced.

3. In a carburetor, a casing, a Venturi tube comprising a plurality of sections including a throat section, said sections being adapted to move within cylindrical portions of said casing, a fuel nozzle for delivering hydrocarbon fuel in front of the throat of said venturi, and cooperating with said throat to reduce the area of said venturi, means for connecting one end of said venturi in communication with the intake manifold of an internal combustion engine, means for connecting the opposite end of said venturi to the atmosphere, manually operable means to move one of said sections, resilient means between said manually operable section and said throat section normally urging said sections apart and automatic means responsive to the vacuum in said intake manifold to move said throat section away from said nozzle and against the action of said resilient means.

4. In a carburetor, a Venturi tube having a movable mouth and throat section, one end of said tube being adapted tobe connected to the in- Sii take manifold of an internal combustion engine and the other end being open to the atmosphere whereby an air stream is created through said venturi, a fuel nozzle adapted to cooperate with said throat section to regulate the richness and amount of fuel mixture delivered to said manifold, operable means to move said mouth section and means to cause said throat section to move toward said mouth section in response to the load and speed of said engine.

5. The combination as set forth in claim 4, in which said fuel nozzle has an annular recess aos/aces adapted to deliver a thin sheet of fuel at right angles to said air stream.

6. 'Ihe combination as set forth in claim 4, and means responsive to the vacuum in said intake manifold to control said throat section whereby a minimum velocity is maintained in said air stream.

7. The combination as set forth in claim 4, wherein said nozzle has a fuel valve arranged centrally of said nozzle.

E. LEIBING. ROBLEY D. FAGEOL.

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