US2260309A

US2260309A - Charge forming device

Info

Publication number: US2260309A
Application number: US292581A
Authority: US
Inventors: Otis C Funderburk
Original assignee: KANE CARBURETOR CORP OF DELAWA
Current assignee: KANE CARBURETOR CORP OF DELAWA; KANE CARBURETOR Corp OF DELAWARE
Priority date: 1939-08-30
Filing date: 1939-08-30
Publication date: 1941-10-28
Anticipated expiration: 1958-10-28

Description

Oct 28 1941- o. c. FUNDERBURK CHARGE FORMING DEVICE Filed Augj zo, 1939 1o sheets-sheet 1 10 Sheets-Sheetl 2 INVENTOR ala/'J c. Fm im( ATTORNEY o. c. FUNDERBURK CHARGE FORMING DEVICE Filed Aug. so, 1939 Oct. 28, 1941.

CHARGE FORMING DEVICE Filed Aug. 3o, 1959 1o sheets-Sheet s ATTORNEY oct. 28, 1941. Q C, FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug. 30, 1939 l0 Sheets-Sheet '4 |N`VENTOR ATTO R N EY Oct. 28, 1941. o. c. FUNDERBURK CHARGE FORMING DEVICE Filed Aug. 30, 1959 l0 Sheets-Sheet 5 w N m ATTORNEY Oct. 28, 1941. o. c. FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug. 30, 1939 10 Sheets-Sheet 6 ATTORNEY Oct. 28, 1941. o. c. FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug. 30, 1939 lO Sheets-Sheet 7 INVENTOR BY @ifm ATTORNEY Oct. 28, 1941. Q c, FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug. 30, 1939 10 Sheelzs-Sheekl 8 ATTORNEY ct. 28, 1941. Q C, FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug. 50, 1939 10 Sheets-Sheet 9 Oct. 28, 1941.

o. c. FUNDERBURK 2,260,309

CHARGE FORMING DEVICE Filed Aug@l 30, 1959 10 Sheets-Sheet l0 Patented Oct. 28, 1941 2,260,309 l CHARGE FORMING DEVICE I lons o. Funderburk, Weston, Mass., assigner, by mesne assignments, to Kane Carburetor Corporation of Delaware,

poration of Delaware- Application August so, 1939, serial No. 292,581 12 claims. (c1. 12s- 122) 'This invention relates to paratus for preparing, a combusti-ble gaseous a method and apmixture in an internal combustion engine, and for so distributing and treating fuel charges as to render them par-A ticularly adaptable for starting and idling con 'ditions, and for all operating cycles.

producing and conveying.

It is on e of the primary objects of this invention to'provide an apparatus in combination with the intake manifold of an engine for producing a highlydgasiied fuel mixture both for general operating and starting conditions whereby a relatively high volumetric eillciency.

of the engine could be obtained, and it is a further purpose of my invention to Aenable the aforesaid objective to be attained in a simple, compact, and readily assembled and disassembled structure, and which is particularly and conveniently adaptable for coaction with air preheating means such as is described in myappllcation Serial Number 292,580 filed concurrently'herewith and relating to a method and Y apparatus for preheating and distributing air.

It is also within the contemplation of my invention, in line with my aforesaid object of effecting a high volumetric, eilciency, to provide a method of maintaining the intake manifold in a substantially uniform and relatively' cool temperature throughout the extent thereof, an objective which I attain by combining a special type of aircleaneroand intake manifold so as to provide a reservoir or chamber for the circulation of air adapted for this purpose. And in this aspect of my invention, it is a further purpose of mine to attain the aforesaid objective by so constructing the air 'cleaner as to enable it to perform its intended functions without contain- -ing the shortcomings of icon ventional drum type or high center of gravityk constructions, with the attendant dangers of undue stresses resulting from lateral vibrations particularly in the so-called oating power designs. In

connection with this phase on; my inventionjitis a further object to provide easier passage of the air from the cooling fan than is possible with conventional air cleaning structures, an objec- Y atomizing system tive whichis accomplished by a reductionof the obs'tructionsrin theslip stream from the fan and by the low disposition and smooth configuration of--the cleaner, with resulting enhanced emcacy ofthe cooling system.

Another object of my invention is to eliminate vapor Jock Y vapors prevalent in Iconventional carbureting mtemparticmarly or stratification of the gasoline luider high temperature ccn- Wilmington, Del., a co1'- ditions, an objective which I attain byshielding the. intake manifold lfrom the direct action of the fan and by employing, as aforesaid, relatively cool air substantially along the entire intake manifold and gasifying System.

It is also within the contemplation of my invention to enable a wide range of fuels, from solvents and other heavy hydrocarbons to relatively volatile fuels, to be effectively gasied and regulated without any change or adjustment of the metering system, a result which is not possible with any known it is a furthera object in connection with this phase of my invention to permit the ready gasification of low gravity hydrocarbon `fuelsfor starting purposes without the employment of name or other dangerous heating'A expedients.

It is another object of my invention to provide, at all operation cycles of means of lifting fuel from a level lower than the carburetor or gasier and formetering and directing 'such fuel into the gasifyin'g and of my invention. And in this aspect of my invention it effect a high ,hydrostatic lift at the moment of cranking, particularly under the direct influence of the suction in the n tinguished from certain known systems dependent upon the suction in the carburetor. It is also my purpose, by employingthe fuel-lift device above referred tional float chamber or fuel supply reservoir, whereby my carbureting system will.work in any position, thereby lending itself admirably for aeronautical work, as well as for industrial, marine, automotive, and military or naval purposes.r A further object of my invention is to so control the operationof the throttle and air valves as to retard their rapid movement, and to thereby offset the electof engine operation bydampening out its pulsations land in this manner eliminate the tendency of said valves to pulsate or flutter. `And I also a'im to provide a flexible throttle valve control wherebythe opening of the "throttle is removed from the direct control Placed' Iunder thel influence although theV operator ldoes of the operator and of engine suction,

have directv control over the closing v.of the throttle;

ing the provision. of a the richness of the -slmple control for v system of carburetion; and

the motor, a positivel is another object tov intakevr manifold, as dis.-

to, to eliminate the convenfuel charge 'without cutting Y;

and preventing the freezing of the fuel supply nozzles in the carbureting system such as occursv taken'aiong une ls-ls.

frequently in conventional aeronautical and l other internal combustion engines.

Other objects, features and advantages will appear from the drawings and the description i hereinafter given.

Referring to the drawings:

Figure 1 is a fragmentary, transverse, vertical section of a V type internal combustion engine containing my invention. the specinc design illustrated being a Ford V8 engine-the section being taken through' the cylinder nearest the radiator on the right bank, looking rearwardly towards theair cleaner and the dash.

Figure 2 is a bottom view of the air cleaner casing of Figure 1.

Figure 3 is a fragmentary vertical longitudinal section taken substantially 'along line 3--3 of Figure 1, this view showing one seetionof the multiple-Venturi gasifying system employed in my invention, and a portion of the primary Venturi starting system.

Figure 4 is a fragmentary transverse vertical section of Figure 3 taken substantially along Figure 5 is a partial plan view of the. engine illustrated in Figures l and 3 with the air cleaner casing removed.

Figure 6 is a semi-diagrammatic development of the engine illustrated, showing the intake manifold with the gasifying system thereover, 'the cylinder heads, and the exhaust preheating system, and illustrating the ow of heat-emitting yand heat-transmitting fluids therethrough.

Figure 7 is a schematic representation of the mixture control button on the instrument panel and its connection with the battery circuit and the emulsifying air' lever.

Figure 8 is a plan view of a cylinder head of the structure illustrated and which is positioned over one'bank of four cylinders.

Figure 9 is a transverse section of the cylinder head taken substantially along line 9--9 of Figure 1. FlgurelO is a part elevation, part section of Figure9 along line I0I0.

Figure 11 is a fragmentary transverse section of a slightly modified form of cylinder head, the A section being taken substantially along line 9 9 of Figure 1,-similar to that of Figure 9.l

Figure 12 is a section of Figure9 taken along ,line IZ-l2.

Figure 13 is a section QfFigure 9 taken along line i3-I3.

associated with the main multiple-Venturi assembly, the throttle fluid dash pot, the accel- 'erator pedal, and connecting control linkage.

Figure 22 is a fragmentary side view of the throttle valve lever assemblyof Figure 21.

Figure 23 is a vertical sectional view of the fluid dash pot construction of Figure 21.

Figure 24 is a sectional plan view of vFigure 23 l taken along line 24-24.

taken sub- I ure 2 7.

Figure is a section of Figure 27 taken substantially along line 311-30, and

Figure 31 is a fragmentary vertical section of Figure 27 taken along line lili-3l.

The method and apparatus constituting my invention contemplates the employment of an intake manifold of special construction cooperating with certain novel forms of gasifying, metering, fuel-lift, and air and gas fuel controls, the manifold being adapted to coact with air preheating units described in my aforesaid copending application. The structure of my invention, and particularly the intake manifold portion thereof, is especially adapted for cooperation with a novel -air cleaner, 'whereby a completely shielded enclosure is provided for the said gasifying, meter- Y ing, fuel-lift and control apparatus, as well as for the intake manifold conduits communicating with the combustion chambers of the engine. The intake manifold casing has'mounted thereover a gasier substantially similar to the structure described in U. S. Patent #2,102,800 granted December 21, 1937. The manifold further prov ides supports for a main fuel supply system at the entrance of said gasifier, and for a combinationl anterior throttle valve arrangement and auxiliaryy fuel supply system for starting .and idling purposes. Both main and `auxiliary (here- -inafter referred to as primary) fuel supply struc- Figure 14 is a fragmentary section of Figure 9 taken along line Ill-I4.

Figure 15 is a fragmentary section-f Figure 9 elevation of the primary Figure 16 is a side venturi and anterior throttle valve casing positioned upon the'intake manifold, the view-being,- I6-I6 of Flgule 5..

- eiken substantially along line. 2li-2o- Figure 21 isa schematic perspective view of Asection-al plan o f I' :the anterior throttle system Shown. operatively/75 Vthrough the suction of the engin tures arefoperative without the use of the conventional -o'at bowl or fuel reservoir characterizing common carburetors, special Venturi nozzles being employed to createl sufciently high depressions, under the various operating cycles of the engine, for drawing the liquidfuel'directly from the main storage tank, whereby this apparatus is rendered particularly adaptable for aviation. The liquid'fuel in the main fuel-lift nomles is automatically metered through a connection lwith the main air intake valve, the latter being of unbalanced structure and heid normally yieldably closed, whereby v it can only be opened 'Hence the amount of the main fuel supply is automatically controlled in accordance with engine demands.

The primary or starting fuel nozzles are positioned in close proximity to the ports leading to the intake manifold conduits, being in this manner subjected to the direct inuence ofthe intake manifold depressions, rather than tdthe depressions prevalent inthe carburetor or gasier as is the case in certain conventional systems. The supply of fuel for the primary venturls `can be regulated, for best idling conditions, by a single readily accessibleknob above the air cleaner, and

' I have devised a system of varying once this adjustment is made, it is generally unnecessa'ry to change it `thereafter. `'10 facilitate starting, particularly under adverse conditions, the richness of the starting mixture without .the use of the conventional choke controls, so that there is no restriction whatsoever of the supply of air to the primary starting venturis, ,such as always occurs when conventional chokes areA pulled out; and' in this manner I obviate floodl conditions during starting. I accomplish this result by providing a method of emulsifying the liquid fuel charge to the -primary venturis with preheated air, and provide means for controlling the amount of such emulsifying air through the medium of a dashboard mixture control button. When this button is pulled out, the mixture becomes richer; and when it is fully pulled out, an electric circuit is closed to energize an electric heating element, which serves the purpose of further preheating, while such button is out, the air directed through the primary Venturi nozzles.

And in order to supply both the main and primary fuel supply systems with suitable preheated air, provision is also'made for receiving' such preheated air from the cylinder headsand exhaust preheating units, and directing a portion thereof to the main gasifler, and by-passing another portion thereof to the primary Venturi system. And the entire 'apparatus rendering the accomplishment of the above results possible is all contained within a compact and readily accessible structure. A

Having'above described the operation of the system constituting my invention in general terms, I will now describe more specifically the apparatus of my invention for enabling the steps above referred to to be eiectuated.

In the drawings, and referring particularly to Figures 1 to 4 inclusive, the air cleaner casing 30 is substantially of rectangular cross section with the roof and corners thereof of arcuate and curved configuration. This air cleaner is of relatively low height, being shown lower than the electric generator 3l disposed forwardly thereof, thereby constituting considerably less obstruction to the passage of the air from the radiator fan than is possible with the conventional drum type of air cleaner, the smooth and curved contour of the air cleaner enhancing this effect.. The air cleaner casing is held in place by ,bolt means 200 extending through the top thereof and operatively connected with the unit H1 to be hereinafter described. At the rear of the air cleaner is the breather pipe 32 and the passageway 33 for admitting lubricating oil through aperture 34 into the crank-caseof the engine. The air cleaner 30 is further provided with Vrearwardly opening louvres 35 for receiving the air from the atmosphere, this air passing through metallic foil 36 held in place by the Wire screening 31, the entire air cleaner casing resting upon a circumferential gasket 38 surmounted upon the upper peripheral wall 39 of the intake manifold4 casing 40. In the' preferredE construction, the lower periphery terminal edge 4I of the air cleaner casing lis of channel-like structure to properly accommodatethe said gasket 38. The inner wall of the aircleaner casing 3.0 is also provided with layers of Aheat-insulating and sound-absorbing upper portions eral wall 44 completely surrounding the interior of the manifold to provide an air reservoir, so that all the air drawn in through the louvres of the air cleaner will be kept confined withinthe walls of the cleaner casing 30 and the walls 44 of the intake manifold, to be subsequently diverted to other paths in the manner hereinafter set forth. Cast integral with the casing of the intake manifold are two conduits leading to the intake valves of the engine, the-upper conduit 45 leading to the two center cylinders on the right bank and the two end cylinders on the left bank and the lower conduit 46 leading to the two center cylinders on the left bank and to the two end cylinders on the right bank. Extending transversely across substantially the central portion of the intake manifold casing kand joining the of the longitudinal lateral walls 44 thereof is the connecting wall or flange 41 (see Figures 3, 5 and 6) containing two. ports 48 and 49 (see Figure 4) communicating with the upper and lower intake manifold conduits and 46 respectively. As will be hereinafter set forth, the two4 ports are adapted to receive the gasiiied fuel stream both from the multiple-Venturi system and the primary- Venturi system above referred to, whereby such streams will pass directly to the intake valves of the engine. i

The opposite longitudinally extending lateralv walls 44 ofthe intakemanifold casing 40 contain, preferably below the said flange 41,v air outlets 50 and 5| (see Figures 4 and 6), which communicate with the inlets 52 and 53 of the cylinder heads 54 and 55 respectively. These inlets communicate with longitudinal passages 56 and 51 respectively (Figure 6), the former communieating with the transverse air passageways 58, 59, 60 and 6| and the latter with corresponding air passageways 62, 63, 64 and 65, these passageways all being .disposed directlyv above the combustion chambers represented 'by the general reference numeral 66. Each one of the air passageways contains fins or ribs generally designated as 61, and clearly shown particularly in Figure 9. 'I'he intermediate passageways are of enlarged proportions, providing zones of low velocity and relatively large heattransmitting surfaces, for increased' heat-absorbing eiiciency. The outlets of the air passageways of cylinder head 54 operatively communicate with the heat exchange unit 68, and the corresponding outlets of the air passageways, of cylinder head 55 communicate with the heat exchange unit 69. Both of these heat "exchange units conduct therethrough the exhaust gases from the cylinders, the heat thereof being conducted through intervening heat transmitting walls tothe air currents from the cylinder heads as aforesaid. l

The particular forms of units disclosed represent merely two of various other possible devices to serve this purpose, it being understood that this invention is not limited to the two forms x shown in thedrawings. The heat unit 68 receives flow through the material 42, said layers being secured Vin place by the fastening elements '43, this material serving to render the operationof the carbureting system silent aswell as thermally protected.

The intake manifold casing 4l contains a lat- 75 from the exhaust through openings manifold associated therewith 14b the burnt gases which spaces 16 between the outer casing of the unit 68 .and the inner casing^1| carrying the heat-receiving air, and out through opening 14e. 'I'he path of the air is illustrated by arrows. the air casing 1I constructed with a return bend and having therein a plurality of ribs or radiating fins 12. At the opposite end' is the heat exchange unit 69, as aforesaid, the form illustrated conportions of these air Y passing through the tubular the hot exhaust gases entering the unit from exhaust'outlets 14 and.14c are connected to suitable piping leading to the muiiler, the specific ar- I rangement not being illustrated as itis wellknown in the art. passageways of cylinder head 55 follow the course 3 indicated by the arrows of Figure 6, entering the g tubes on one side of lthe baille 15, emerging into the compartment 16 and then pursuing a return course through the remaining tubes as indicated. The air streams from both preheating units areA then directed by suitable pipes 11 towards the intake manifold casing, both streams of air being Siamesed through the Y portion 18 shown as an integral portion of the intake manifold casing.

The air from the transverse It should be noted that the cylinder heads 54 5 and 55 are constructed to permit the operative 1 passage therethrough not only of air, but' also of water. Referring to Figures 9 and 10,'the airfrom inlet 52 is divided into several parts, the

5 taining a plurality of tubes 13 conducting therein stoodfhowever, that thef cylinders may be fied in any other vsequence of suction on either bank,

within the scope of this'mvenuon. A detauea' Y operation of the two

Venturi conduits

93 and 94 will not be attempted here, inasmuch as its operation is fully set forth and described in said Patent No. 2,102,800. Sumce it to say that each set consists of a plurality of successively expanding overlapping Venturi tubes, the overlapped terminals of each tube being disposed within a Apredetermined portion of the throat of the overlapping tube, certain of the terminals being serrated. The overlapping arrangement is such as to provide circumferential gaps between adjacent;-

venturis to permit the introduction of air for interpenetration and thorough admixture with the atomized fuel streams within the conduits. Both sets of venturis are suitably mounted within a housing 95, being supported by pedestals 96 secured by screw means91 to the base of the housing. The upper portion of the housing 95 contains an -inlet duct 98 for supplying air to the ducts 19 and v80 being adapted to receive through the openings 8| and 82, respectively, certain pori tions of this air to convey such portions to the passageways 58 and 6| respectively, the remainder of the air 'from inlet 52-owing directly into the passageways 59v and 60. And by referring to Figures 10, 12, 13,-14 and 15, it will be observed that passageways for water are also provided,

these being designated by the

reference numerals

83, 84, 85, 86, 81 and 88. Only fragmentary portions of the water jackets, however, .are disposed over the combustion chambers, these high temz perature regionsl being reserved primarily for the air passageways, for reducing the warming up period, increasing the thermaleiiiciency, and for the other reasons herein set forth.

And again referring particularly to v Figures 8 and 9, it will be observed that the bosses generally designated by the reference numeral 89 are adapted t'o receive therethrough suitable studs Acircumferential gaps .of said multiple-venturis,

said duct having therein a rotatably mounted valve 99, this valve being preferably mounted offcenter and normally kept closed by yieldable means to be hereinafter described, and being hence adapted to be opened only underthe iniluence of the engine suction; and the outlet end of the housing is provided -with two outlet ports |00 and |0|.

Extending through the opening |02 at the rear of the housing' 95 are the main Venturi fuel nozzles |03, to be mor fully hereinafter described, the terminal portion o eachof these nozzles extending into the corresponding rst Venturi tube |04 (Figure 3). The nozzles |03are suitably supported within the block |05 which contains thereon a chamber |06 housing certain metering apparatus for controlling the .ow of the liquid fuel into the nozzles. |03, as will be more fully hereinafter set forth. The chamber |06 is also profor attaching the cylinder heads to the engine block. The depressed portions 90 contain threaded apertures 9| therein for receiving the spark plugs.

The modication of Figure 11 may at this time be referred to as merely representing a slight departure from the structure of Figure 9. Here two tubular elements 92 of insulating material are inserted in the ducts v19 and 80, to prevent a cooling of the air before -entering the transverse passageways in the cylinder head. In all other respects this form of my invention is similar to that of Figure 9. A

Referring again to the-path of the air after leaving the

heat exchange units

54 and 55 and entering the intake Amanifold casing 40, a portion of this air is directed-into the multiple-Venturi gasifying system above referred to, and another portion is by-passed towards the primary Venturi system for supplying a combustible mixture to the engine for starting, partial throttle and idling purposes. In order to enable the action and effect of the air from this point on Ato be fully understood, it will be necessary to describe the arrangement of the said Venturi systems. In the particular form of my invention as illustrated, a dual set of multiple venturis is emvided with a protecting cap |01 as illustrated. Said block |05 contains therein the passageway |08 for the liquid fuel from main fuel line |81 (see 'Figures 3, 28), the liquid fuel being -con ducted, asY will hereinafter appear, to the annular chamber `|09 in eachA Venturi nozzle |03, from' which it is drawn into the region of the throat of the nozzle by the depression prevalent therein due to eng'ine suction. The details of the nozzles |03 are similar to primary nozzles |25 and |26, and these together with the specific metering arrangement wil-l Abe later referred to and described ingreater detail for clarifying the operation of this device.

Attached to the rear of block |05 is the fitting ||0 (Figures 3, 5 and 26) which at the lower flanged terminal thereof communicatesvwith the aforesaid Y portion 18 of the intake mani-` fold casing to permit the entrance of the air from the aforesaid exhaust preheater units. The said fitting also contains a second outlet I2 which communicates with a tubular by-pass forming part of the housing unit'95 and extending longitudinally therealong, as clearly shown in Figure 5.

It will be noted that the said block |05 is sepa' Y intake manifold casingis the primary mixing.

duct |35 extends.

chamber and throttle valve unit I |1, shown Figures 3 and 16 to 20. This unit serves nume municating with the two primary venturis |25 ous purposes, including -the support of suitably controlled unbalanced throttle valves within passages for admitting into the

intake manifold conduits

45 and 46 the gasied fuel stream from the aforesaid main multiple-Venturi system; thecreation of a sufficient depression, under the direct iniuence'of the intake manifold suction, to introduce into the engine a gasied combustible mixture at the instant of starting; to preheat for starting purposes suilicientv quantities of previouslyl heated air to insure combustion; to provide for quick heating of mixture chamber by the direct action of the exhaust gases passing through a heat bridge; and to enable a manual control of the richness of the starting mixture to lbe readily eifectuated without restricting the supply of air.

The by-pass ||3 communicates directly with the duct ||8 in the unit ||1, this duct joining and.communicating with the transversely disposed air channel ||9 in said unit, such juncture being shown in Figure 5. The inner wall of channel |'|9 is lined with suitable insulating material and contains therein the electric heating element 2|, which is connected by suitable conducting means, including the wire |22 (Figure 4), to the battery andl starting mixture control button |68the circuit being shown in Figure 7 and hereinafter described. The auxiliary air channel ||9 contains in the lower wall thereof the said primary surrounding the throats two openingsv |23 and |24 from which extend the l two auxiliary venturis 25 and |26, these being disposed within the ducts |21 and |28 respectively, the ducts being in registry with the openings 49 and 48 and hence in communication with the ment of knob |53 to be

intake passageways

45 and 46 of the intake manil fold.

Each of theauxiliary venturis |25 and |26 is substantially similar to the venturi construction of nozzle |03, and comprises an inlet portion |29 and an outlet portion |30, both of said portions being of conical configuration with the apical portions in proximate but spaced relation thereby providing in the region of the throat thereof a gap |3|`. Surroundingthis throat region is an annular chamber |32 containing a'plurality of apertures |33 which communicate with another annular chamber |34 into which the fuel inlet Hencev fuel operatively introduced into the annular chamber-|34 will be drawn through the apertures Iber |32, and thence throughthe gap |3| at the throat ofthe venturi downwardly towards the intake manifold. -The preheated air entering the inlet portions |29 of the said venturis through the openings |23 and |24 create a considerable depression .in the throat of .each of these venturis, the vdepression beingsuflicient to draw in from the'fuel line |36 leading the auxiliary fuel directly to the fuel tank.V heated state of venturis |25 and |26, avery thorough vaporization ofthe liquid-fuel is effected, thereby insuring ignition in the cylinders. And to'assure starting without flooding the manifold under the compara-v tively unfavorable and to provide ifor smooth idling operation, my invention furthe; controls the flow of the air and gases as will hereinafter be explained.'

For the purpose of` initial starting, liquid fuel l forthe unit |1 is conveyed through the auxiliary fuel line |36 to the inlet channel |'31 which ^in' 36 and |39, the latter comtersects the chambers I 133 into the annular chamconditions of a cold engine, 1

`andV |30, and'through the jets '|4l`and Ill.-` Inuisisim'nmulyuiv. preheated air coursing` h passageway 6| and valve member |59I into 1 l transverse air chnnerlsa-to be-drawddown endthrush l |40 and |4| and the two by the reference nu' with the walls of the two emulsion" air ducts.` |`|1 are the threaded |46 within the body of unit stems |41, each of these carrying a needle valve pin |48 operatively engageable with a valve seat |49 .communicating with a channel |35. threaded stems |41` extend upwardly through the body of unit ||1 and have attached to their upper terminals the two gears |50 which flank and Said latter gear is xedly engage the gear |5 attached to lthe coup |52 mounted thereover,

said coupling and associated gears being rotatable to raise and lower the valve pins |48, through the medium of a knurled knob |53 (see Figure 3), mounted on a shaft |54 extending'through the air cleaner casing 30. Said shaft extends downwardly into the axial aperture' |55 in the said head |52 and is maintained in xed relation thereto by the pin |56 extending through the slot |51 in said head. Yieldably urged outwardly by spring |98 from'the lock pawl |99 in engagement with the teeth of gear |5| to retain it in its projected position, and also to lenable the extent of rotary moveand conventional manner.

Both of said air ducts 46 are connected to the channel |58 (Figure 17),

transverse air-bleed which communicate with the valve member |59 (Figure 19) positionedwithin. the air duct |60.

Communicatingv between air duct |60 andthe auxiliary air channel ||9 is thepassageway |6|; and positioned within the duct |60 valve pin |62 normally ,kept in its with respect to valve seat at |59 open position `by the normal position of the mixture control button |66'to be.

In the operation` of the primary mixing cham ber of unit 1, preheated channel ||9, as aforesaid, wardly through the |26, thereby causing 'a depression in the of these venturis, the vacuum in the manner drawingv up vthe through the fuel and is4 directed ldownnne m.' into the chambemm asmuch as the valve member obstructed andl open',fthe

through the-'channel un also enters' through the emulsion auf duets m the valves |49,th e`reafter to be The mayor the unit uns the' determined, in well-known is the needle upon which is' mounted Y air'enters auxiliary air auxiliary venturis v|25 andv tlirolff;A under the direct 'influence lof 4 hydrocarbon fuel uch f yair above-referred to.

turcs 133,. and down said venturis tc mix with the air flowing downward through the throats of the venturis. It will thus be noted that under these conditions, instead of hydrocarbon in the usual` 1iquid form being introduced into the mixture stream, an emulsion of heated air and the fuel is introduced into the venturis. My invenfuel by-passed through small orifices around the throttle as is done in 4conventional carburetors,

freezing 'up of the throttles in certain atmoshigher value, the said venturis begin to discharge fuel, and being heated as above described, im-

, mediate atomization and gasification of the\fuel Y ensues, thus preventing the formation of ice on the periphery of the throttle valves |15 (Figure 3) and causing them to freeze against the throttlel bore which commonlyoccurs in conventional carburetors at this cycle of operation. The said venturis |25 land |20 having their discharge portions |30 pointing downwardly and ahead or anterior to the throttles |15 inthe combustible mixture conduits 48 and 49 are thus fed with a combustible mixture, not having to pass the periphery of the said throttle valves |15, in this way eliminating the hazard of freezing or forming ice coating on -the periphery of the said throttle plates.

In controlling the idling' fuel-discharge on an anterior throttle type carburetor, it is desirable to airbleed the fuel discharge jet to eliminate sensitiveness of adjustment-and the necessity for extremely small diameter orifices. By referring to the Figures 18-20 it will be found that my invention eliminates the objections with a conventional carburetor. The said jets referred to are designated by the reference numerals |40 and I 4|,` and the air bleed system by the reference numerals |40 and |49. With the construction above-described,V the bleeding of the airthrough channels |35 when the valve |59 is open 'will 1 tion for providing idling and starting mixture enhances atomization and because there is no whereby the air is practically shut off to cause over-rich conditions.

The arrangement is such that when the mixl ture control button |08 on the instrument panel is fully pulled o'ut, the pin |02 will completely close the valve |59, and at the same time the circuit through the heating element 4|2| and the l battery will be closed. This is effectuated by the engagement of the lug with the lever |0| of the switch |82 in the circuit. This obviously causes a further heating of the air coursing through channel ||9 and entering the said primary venturis. Hence, when it is desired to start a cold engine under adverse conditions, the said button |08 is pulled out to its fullest extent, thereby enabling undiluted and unemulsied liquid fuel to be introduced into the Venturi system, together with extremely preheated air. The amount of preheated air required to produce` this result is relatively small, and hence the amount of electrical energy consumed over the short period of time the circuit'is closed is not excessive.l

It has been found that inasmuch as the venturis izscnd |26 are subjected tc the direct influence ofthe intake manifold depressions and not to depressions that are prevalent in carburetors (aswith some conventional designs), there is suiiicient suction through the auxiliary jets |40 and |4| to `enable a considerable hydrostatic fuel-lift to be effectuated thus dispensing with need for auxiliary means of supplying fuel tol 'the auxiliary Venturi system through fuel line |30. When, however, particularly during the starting or -idling operation of the engine the depression in the intake manifold should decrease, ,a pulling out of the mixture control button |08 will cause, as aforesaid, a shutting od of the emulsifying air and consequently produce an increased suction on the fuel flowing through vthe jets |40 and |4|, thereby making it possible' atv all times, under the most, adverse conditions, to effect a suflicient hydrostatic fuel-lift for practical purposes through the auxiliary venturis. It should however be. noted that the fuel lift arrangement'in the throttle body unit ||1 is primarily used for starting a motor. Provision is y made for enriching the mixture for this purobviously decrease the suction pull at the throatsy link |19 in the direction of the arrow to rotatably actuate the lever t|03 to bring the needle valve pin |02 from its open position of 'Figure 19 towards itsclosed position. When this occurs, the amount of emulsifying air vbeing' admitted pose' and for warming up e engine as aforesaid. Should need arise in 'operation of the engine to increase the hydrostatic fuel-lift, suc-4 tion on the fuel feed line. |30 is proportionately increased by pulling out the button |00 on the instrument panel (Figure '1) which actuates the metering needle |02 (Figure 19,) closing o the' aperture in seat |59, thus causing a restriction in the air flow from atmosphere through paslnge |0| .thence through passage |50, communil cating withjemulsifying duct |40. The degree for admixture with the liquid -fuel is accordingly a Y decreased, thereby proportionately yincreasing the amount of liquid fuel introduced into the venturis |25 and |20. This however does not affect the amount of air beingA introduced from the hot qu;

air channel |9,through. vthe outlets |29 and |24 into the auxiliary venturis |25 and |20, the only air that is .cutoff beingl the so-'called emulsifylng- This is hence distinctively different from the fuel in the of the suction eifectuated is determined by the position of the valve |02, in the valve seat I 5 9, thus effectuating a hydrostatic rise in the fuel column passing through fuel line |90,` thence through passage |31, auxiliary jets |40 and |4| and venturis |25 and' |20. The auxiliary venturis |25 'and |20 further serve as the idling discharge continue discharging hydrocarbon take mixture throughout a partial nozzles an throttle range. The degree and period of this discharge is determined by the intakemanifold depression and the differential in the size of the orifices in thel auxiliary fuel jets |40 and |4I, and

the apertures presented in the annulars between the "metering needles |40 and the needle seats |49 (Figure 20). The fuel f romline |01 for the conventional choke control 74 multiple venturls constituting the mam giisifyferred to. 'I'he system can be so designed, in accordance with my invention, that below a certain predetermined intake manifold depression, the auxiliary fuel supply from line |36 will be cut off, and fuel supplied only through the main gasifying system froni line |81; and it has been noted that in actual practice the pull on the main fuel line |81 remains practically constant after certain speeds are reached, regardless of subsequent increases in intake manifold depressions.

For initial idling setting, each adjustment can be set separately. 'I'his is'accomplished by re- My invention promoval of the hexagon nut 200, air cleaner cover 1 30, backing out lock-screw 215 lifting pinion gear |5| upward out 'of mesh or engagement with gears |50. This allows a rotative movement of each threaded stem |41 and needle valves |46 for separate idling setting for each throttle valve |15. When this setting is made, pinion gear |5| on certain vof the cylinders of the engine. Said exhaust ports form a branch of the respectivey exhaust manifolds attached to the outer wall of the cylinder block on both the right hand andv the left hand side 'of the engine. The arrangement is such as to cause a portion of the burnt or exhaust gases to be directed through the said ports |13 and |14, into ports |1| and |12 and through the passageway |10, to produce alternating surges of such burnt or exhaust gas currents. In this way the region surrounding the auxiliary venturis and |26 will be preheated during the operation of the motor. The dissipation of heat through the walls of the said throttle body unit ||1, (Figures 4 and 5), entering the combustible intake mixture, assists the atomization and the gasification of the fuel and is conducive to smoother running especially at idling and part throttle operation. It is, however, to be understood that this exhaust heat jacket or heat bridge so called, can be dispensed with by merely plugging up the ports |1| and |12 or by providing valves for either manually or automatically controlling the ow of exhaust gases through said ports |13 and |14, f

The casing |I1 also is adapted to contain therein the anterior throttle valves |15 and |16, these being positioned between the discharge ends of the multiple Venturi gasier and the intake manifold. These throttles are mounted offcenter on shaft |11 extending through the body of the casing, the shaft being operatively conis meshed in engagement with the respective gears and lock-screw 215 is screwed in, thus keeping the said pinion |5| meshed in engage- 'ment with the said gears |50. Thereafter, any

rotative movement of pinion gear |5| will move gears |50 in unison. This is an important feature of my invention as the idling adjustments for venturis |25 and |26 can be set on a flowbench or a motor at the time of the manufacture of the carburetor or gasifier andynchronized as above described, thus assuringA identical idling settings when the device is attached to the motor on which it is lto be used. It is especially beneficial in motors of thevV-type 4wherein one carburetor throttle controls the ow of combustible intakel mixtureA to some vcylinders on one bank and to other cylinders on the opposite bank ofthe engine, as is the case with the Ford v-6 engine referred to in this specification. By synchronization of the lflow of combustible intake mixture through the anterior throttle discharge Venturi nozzles |25 and |26 referred to above, a more uniform ratio of fuel'to air is obtained not only in the idle adjustment setting but part throttle operation as well, This results in Asmoother running of the engine.

To insure quick warming up of the throttle body unit ||1 (Figure 1'1) and for smooth running in normal operation of the. engine, an ex'- haust jacket or heat bridge |69 surrounds the lower portion of the said throttle body unit ||1.

nected to the accelerator, pedal in a manner to beV hereinafter described.

Normally, as'aforesaid, the-throttle valves are in their closed positions under the inuence of spring |83. When the engine suction causes an opening of the unbalanced throttle valves |15 and |16, due to the pressure differential on opposite sides thereof, the disc will rotate in a clockwise direction (Figure 22) luntil the lug 2|1 encounters the stop 2| 9, beyond which the valves cannot be opened. The position of the stop 2|9 is obviously controlled by -the position of the accelerator pedal |84, a depressing thereof resultingin a movement of the link |85 and rod 2|4 in the direction of the arrows (Figure Z1) to cause a rotat-ion of the lever 2|5 in a clockwise direction, or in a direction away from the normal position of the stop 2 |1. A Hence when the pedal is pressed down for more gas, all that is done is to draw the stop 2 |9 away from the lug 211, thereby permitting the throttle valves to open by the engine suction to a point controlled by the action of the accelerator pedal.` I

There is thus no direct opening effort exerted by the pedal. But the operator has, nevertheless,

as much as a release of the pedal |84 under the Vinfluence of spring |83 will cause a counterclockwise movement of the lever 2|5, thereby forcing the lug 2|1 (with which it is in engage- `matic control of the offset axisthrottle valves prevents the sudden drop in depressions in the Aintake manifolds, thus assisting the carbureting system to charge each respective cylinder with' the proper amount of combustible mixture, thus tending to eliminate detonation or pinging. I

In order to dampen out all utttering of the sensitive anterior throttle valves and |16 due A1 vto engine pulsations, -I employ the liquid dash p ot deviceV |18. Attached to the shaft |11-is the arm 220, and pivotally detached to the outer end thereof is the link 22|. Pivotally attached at 222 of the link is the piston 223 containing therein a hollow chamber 224 open at the bottom and provided therein Awith the disc-like valve 225.

The upper peripheral edge 226 of this valve is bevelled for engagement with the correspondingly bevelled upper portion 221 of the interior of l chamber 224. The valve 225 contains the peripheral vertical slots 228a intersecting the bevelled annular peripheral edge 226; and the piston is provided with a plurality of radially extending channels 228 communicating between the upper portion of the piston and the wall 230 of the cylinder 23|. And positioned within, a suitable annular groove in the lower portion of the wall of the piston chamber 224 is the lock ring 232 forming a lower seat for the valve 225.

The cylinder 23| is filled with any suitable fluid, such as alcohol, oil or mercury, preferably up to level 2'33 above the level of the channels 228. -Upon an opening movement of the valves |15and |16 the piston rod and piston will be urged downwardly. This causes the valve 225 to be elevated by the uid pre'ssureuntil the bevelled edge 226 thereof is seated against the wall 221 to completely shut off channels 228 from communication through the interior Aof the piston with the interior of the cylinder.the upward movement of valve forcingout any air that might be trapped in the upper part of chamber 224.

Upon the continued downward movement of the piston, the iiuid from the cylinder will be forced upwardly through the relatively small space betweenthe wall 230 and the body of the piston, and then through space 229 to overlie and submerge the top 235 of the piston, the cylindrical wall 230 keeping the fluid conned withinthe vessel. It

main gasifying system is also normally yieldably kept closed, and operable under the inuence of the engine suction. I prefer to employ in"as sociation with valve 99 an air dash pot device 205 controlled by the depression prevailing in the mixing chamber of Venturi conduit system-a description of this device to be hereinafter given.

The fuel inlet means provided at the entrance to the main mixing chamber is associated with the metering block |05, and is fed by a main fuel line |81, as aforesaid. 'I'his communicates through channel |08 with the two passageways' amount of fuel drawn into the Venturi nozzles through 'the medium of the needle valve terminals |92 and the valve seats |93. The said metering-pins are secured to and suspended from the lift blocks |94, which contain overhanging flanges |95 overlying the lifting lever |91 xedly mounted upon metering shaft |96. The metering pins are threaded into the .said lift'l blocks so that they can be properly adjustably positioned within the passageways |89, and once set, they will be held against displacement by the lock nuts 206. The metering pin springs 201,preferably held in proper position by the bosses 208 and upper terminals of the metering pins, are illustrated as being in abutment with said lock nuts to normally urge Athe metering pinsinto their lowermost positions, whereby predetermined minmum amounts of fuel will be delivered to the nozzles |03, in accordance with the specific design and operating requirements.A

Also xedly attached to said shaft |96 is the roller lever arm 209, the outer terminal end of which contains the roller 2|0 normally kept in.

engagement, under the influence of springs 201, with the cam 2| xedly. secured to the shaft 2 |2 of the air valve 99. The air valve is connected through lever 2|3, also mounted on shaft 2|2, to the dash pot 205, which normally keeps the l air valve in its closed position, as will more clearly hereinafter appear.

In the operation ofthe above-described metering device, it is apparent that the amount of liquid fuel drawn into the main multiple-Venturi system through nozzles |03 is dependent upon the position of the air valve 99, inasmuch as an opening movement (counter-clockwise in [Figure 29) of the valve will cause a corresponding rotation ofthe camA2| I, roller arm 209 and is thus seen that an opening effort upon the throttle valves is resisted by the action of -the fluid, although an operative movement is permitted due to the upward movement of the cylindrical column of liquid.

When a closing movement is imparted to the throttle valves |15 and |16,the arm 220, the link 22| and the piston will be elevated. When this:

ing a. dampening effect on the opening movement of these valves.

The lmain air valve 99 at the entrance to the lift lever |95. Andupon an upward movement of lever |91, the lift blocks |94 and the metering pins |9| will be correspondingly lifted, against the action of springs 201, to admit more fuel through the channels into the nozzles |03. The valve 99 being, as aforesaid, mounted offcenter, it will be opened, against the action of the dash Apot device 205, by the engine suction. Hencethe. arrangement is such as to provide for an automatic control ofthe main liquid fuel supply-in accordance with engine demands,l the 'to the operative opening effort exertedupon the airvalve `99 fat low. speeds lthan at high speeds,

and that thisresistance be decreased as the enthroats in venturis |03 supply the increased demand for air, hence the `,With arm 2|3 forms a beam me proportionately more air will be admitted to the.

mixing chamber. This is effectuated by the dash pot device 205 which contains the cylinder 240 and the piston 24| connected by link 242 to arm 2|3 aiixed to the air valve shaft 2|2. The spring 243 within the cylinder normally urges the piston upwardly and the air valve 99 into its closed position. Extending from the bottom of the cylinder 2 40 is the tube 244 which communicates with the interior of the casing 95 housing the main venturis which receiveand vconduct the air and fuel mixture. Thus the depression withv in housing 95 caused by the enginesuction is communicated through tube 244 to the interior of dash pot cylinder 240 to pull the piston 24| down and consequently help to open valve 99 against the action of 'spring 243. Hence at low speeds, when the depression within casing 95 is low, owing. tothe free ow of air through the secondary venturis |03, the engine suction will have relatively little yeii`ect-on piston 24|, so that under these conditions comparatively little air will be admitted through valve 99. But as the power and speed of the engine increases, the become inadequate to depression within-the housing 9,5 will be corre.- sponding'ly increased, causing a greater opening 'of the valve 99 for the admission of more air into the mixing chamber.

Cooperativelyassociated with dash pot 205 is thefluid dash pot device 250 connected through link-25| and arm 252 to the air valve shaft 2|2. 'I'he arm 252 is afxed to shaft 2|2 and together mber adapted to reciprocatingly actuate the pistons 24| and 253 in opposite directions. Although lthe cylinders 240 and 254 are illustrated as being separate units, it is of course understood that they can be combined in a single unitary `structure. The said piston 253 contains a vertical passageway 255 thereinxextending to the bottom surface thereof, the passageway containing a ball check valve 255 for permitting an upward ow of fluid throughthe passageway, and preventing a downward ow therethrough, in well known manner.

Normally when the air valve 99 is closed, the piston 24| is in its uppermost and the piston 253 in its lowermost position, the cylinder 254' containing therein aselected liquid. When the .valve 99 is operatively opened and the piston 24| ered, the piston 253 will be caused to rise against atmospheric air pressure, creating a vacuum underneath the piston and gradually drawing down the fluid along the peripheral space 258. This action obviously has a retarding influence upon the opening of valve 99, thereby not only preventing a fluttering of the valve, but also serving to maintain a sustained nozzles, as'will more clearly hereinafter appear. During the upward movement of piston 253, the check 250 will obviously close the

passageway

255,4 whereas during the down stroke of piston 253 the ball check will move out of its obstructing position to permit the upward flow of the fiuidthrough the eway. Thus dash` pot -259 also serves toprovlde greater resistance to the opening of the air valve than to its closing,

-and'is a valuable adjunct to dash pot 205 whose effectiveness irl-restraining the opening of valve d with engine suction which is com-- municated to cylinder 240 through tube244, vas aforesaid.

pull onthe main fuel Y the'slip stream The action above described is of considerable Being floatless,

`the motor by of the main throttle valves would cause a decrease in the depression in the main, Venturi mixing chamber, with a consequent decrease in the suction pull exerted onthe main fuel supply nozzles, a condition which would be aggravated by the production of a lean mixture caused by the inrush of the air through inlet 99. But with the retarding inuence upon air valve 99 by the mechanism above described, sufcient depression is maintained in the mixing chamber during acceleration to uninterruptedly draw the fuel from the main fuel nozzles.

It is thus apparent that by the structure and method of my invention as hereinabove described,

the fuel charge for the engine is so prepared,'

treated and distributed Yas to enhance the operative eiciency of the engine under starting, idling and general operating conditions. The intake manifold is so arranged in combination with certain gasifying, heating and cooling apparatus that while being maintained uniformly cool throughout the extent thereof, it nevertheless permits a thorough preheating of the starting and main gas mixtures for gasification purposes. The fuel stream is'so treated that while undergoing a thorough pulverization it nevertheless is subjected to a mechanical refrigerating process so that the charge enters the combustion chamber at relatively low temperatures, with consequent high volumetric efliciencies. In fact, the very considerable temperature drop in the charge from its preheated to its 'nally cooled state is indicative of the relatively large amount of energy consumed in eiecting the gasification of the mixture stream. The gasifying and metering systems combine with the preheating system to without any adjusting operations, and also to permit fuel to be lifted at the instant of starting as well as during all other operating condi-- tions of the motor, without, the use of auxiliary means and the conventional carburetor float bowls. 'Ihe system of my invention minimizes the chance of flooding or over-richening the mixture for starting andwarming up the motor; the danger of frozen -throttles and supply nozzles as no hydrocarbon is by-passed around throttles and through'small orifices, as is the case with .many conventional carburetors. .reduces to a minimum chances of vapor-lock conditions in the fuel supply sys.- tem frequently found in conventional carburetors, provides for the operation of the motor on a wide rangeof fuels in point, reduces the nre hazard to a degree not yet obtained by any other carbureting device so far as -I am aware, provides 'for suflicient cooling of increasing the thermal eiliciency and by reduction of obstructions in the path of of air from the cooling fan. All these results areobtained by a simple, compact and readily accessible structure. 1

Although my invention as above described is illustrated -in the drawings as being specifically applied to a Ford v8 engine', it is of course understood that it" is equally adaptedfor use It is also understood that other additionaly forms the length of voir communicating the mixing chamber and the said outlets, respectively.

: necting wall communicating nicating between the atmosphere 1 main mixing chamber.

and modifications of the apparatus and adaptations of the method constituting this invention can be employedrbeyond and in addition to those hereinabove described, all within the scope of the appended claims.

What I claim is:

,1. In an internal combustion engine, an air and fuel mixing chamber, an intake manifold casing containing conduit means extending along the length thereof and communicating between said chamber and the intake valves of the engine, the casing having a peripheral wall surrounding `said conduit means, a cover surmounting said wall and completely enclosing said chamber and forming an air reservoir with said wall extending substantially along the length of said conduit means, the said reservoir communicating with the atmosphere.

1 2. 1n an internal combustion engine, an air and fuel mixing chamber, an intake manifold `casing containing conduit means extending along the length thereof and communicating with the intake valves of the engine, a. peripheral wall surrounding said conduit means, a connecting wall extending transversely across the casing and joining Opposite portions of said peripheral wall, ports in said connecting wall communicating between said chamber and said conduit means, and

a cover surmounting said peripheral wall and forming an air reservoir therewith communicating between the atmosphere and the mixing chamber.

3. In an internal combustion engine, an air and fuel mixing chamber, an intake manifold casing containing conduit means extending along the length thereof and vcommunicating with the intake valves of the engine, a peripheral wall surrounding said conduit'means, a connecting wall extending transversely across the casing and joining opposite portions of said peripheral wall, ports in said connecting wall communicating between said chamber and said conduit means, air preheating means outside of said cas- A ing, air outlets in said peripheral wall communicating with said preheating means, preheated air conduit means communicating between said preheating means and said'mixing chamber, and

a cover surmounting sa1d wall and completely enclosing said chamber and forming an air reservoir with said wall extending substantially along said conduit means, the said reserbetween the atmosphere and 4. In an internal combustion engine, a main mixing chamber, an auxiliary mixing chamber,

an intake manifold casing supporting both chambersv and containing conduit means communicating with the intake j a peripheral wall surrounding said conduit valves of the engine,

means, a connecting wall extending transversely across the casing and joining opposite portions of said peripheral wall, ports in said. conbetween said 'conduit means and said two chambers respectively, and a cover surmounting said peripheral wall and formingian air reservoir therewithcommuand the said 5. In an internal combustion engine, a main mixing chamber, an auxiilary mixing chamber,

chambers and containing conduit means. coml y municating with the intake valves of the engine,

a. peripheral wall surroundini said conduit means, a connecting wall extending transverse- 6. In an internal combustion engine, the combination according to claim 4, said auxiliary mixing chamber being disposed directly above and supported by said connecting wall.

'7.-In an internal combustion engine containing two banks of cylinders, an air and fuel mixing unit, an intake manifold casing containing an upper and a lower conduit extending substantially along the length thereof, each of said conduits communicating between said unit and one of said banks of cylinders, the casing having a peripheral wall surrounding said conduits and a cover surmounting said vwall and completely enclosing said unit and forming an air reservoir with said wall extending substantially along the length of said conduits, the s'aid reservoir communicating with the atmosphere.

8. .In an internal combustion engine, the combination according to claim 4, further provided with housings for said mixing .chambers joined by flanged connections,`a tubular by-pass associated with the housing for the main mixing chamber and connected to the housing for the l 'ductin the housing for the main chamber and independent of said fitting, and fuel inlet means connected to said chambers.

9. In an internal combustion engine, the combination according to claim 7, the mixing unit comprising two mixingchambers independently connected'to said upper and lower intake inanifold conduits respectively.

l0. In an internal combustion engine, the

combination according to claim 7, the mixing unit comprising two substantially paralle1 sets of overlapping venturis, air and gas inlet means associated with said venturis, ahousing for said unit, pedestals in the housing supporting said venturis, and two independent passageways communicating between said two sets of venturis and the two intake manifold yconduits respectively.

11. In an internal combustion engine, a main mixing chamber, an auxiliary mixing chamber,

an intake manifold casing supporting bothy chambers and containing conduit means communicating with the intake .valves of the engine,y I" Ya peripheral wall surrounding said .conduit means, a connecting wall extending transversely across the casing and joiningI opposite portions of said peripheral wall, portsl in said connecting wall communicating between said conduit means and said two chambers respectively, anterior throttle means between the terminal of said main mixing chamber and the said ports in said connecting wall, unobstructed ducts communi-1v .cating between said auxiliary mixing chamber air outlets in c