US2580294A

US2580294A - Fuel injection carburetor

Info

Publication number: US2580294A
Application number: US19511A
Authority: US
Inventors: Griffon Gaston
Original assignee: CALLED SOLEX Sarl SOC
Current assignee: CALLED SOLEX Sarl SOC; SOCIETY CALLED "SOLEX " Sarl
Priority date: 1947-04-26
Filing date: 1948-04-07
Publication date: 1951-12-25
Anticipated expiration: 1968-12-25

Description

Dec. 25, 1951 G. GRIFFON FUEL INJECTION CARBURETOR Filed April '7, 1948 INVEN OR I ATTORNEY Patented 15cc. 25, 1951 UNITED STATES E ATEN'T OFFICE FUEL INJECTION CARBURETOR public of France Application April 7, 1948, SerialNo. 19,511 In France April 26,1941

8 Claims. (01. 2.61 4 1) The present invention relates to fuel injection carburetters, that is to say carburetters without a constant level device and in which the fuel is injected under the action of a pressurewhich varies automatically with and in the same way as the suction existing in the engine'induction conduit on the upstream side of the throttle member which determines the useful section of flow through said conduit.

In the U. S. Patent No. 2,392,055, filed in the name of Marcel Mennesson for Carburetters of theFuel Injection Type, was already described a carburetter of this kind in which the fuel injection pressure is regulated by means of a valve controlled by means of two diaphragms of different areas and the opposed surfaces of which are simultaneously subjected to the suction existing in the engine induction conduit, on the upstream side of the throttle member, the outer face of the larger diaphragm being exposed to atmospheric pressure (or to the pressure existing in the carburettor inlet), whereas the outer face of the smaller diaphragm constitutes one of the walls of the chamber into which fuel is admitted after flowing past the valve which serves to regulate its pressure, said chamber supplying fuel, through one or several calibrated orifices, to the jet used for running the engine under load. This jet is substantially protected against the suction existing in the engine induction pipe due tothe fact that it opens into a nozzle, provided either on the downstream or on the upstream side of the throttle member and the inlet of which, exposed to the atmosphere, is at a substantial distance from said jet.

The object of my invention is to provide a carburetter of this type which is better adapted to meet the requirements ofpractice than those provided up to now.

It consists chiefly in making the main jet, when it opens on the downstream side of their throttle member, substantially free from the action of the suction existing in the engine induction conduit so that the flow rate therethrough varies as a function of the flow rate of air through the carburetter, whereas the idling jet is operated by the action exerted directly upon the fuel by at least a portion of the suction existing in the carburettor body, on the downstream side of the throttle, when the engine is idling and said throttle is very little opened in order to cause the control valve provided at the inlet of the fuel chamber to open more or less according to the value of this suction.

According to a second feature, I provide in'the conduit through which fuel is fed to the normal working-jet and-onthedownstream side ofthebranch leading to the idling jet, a check valve.

arrangedto permit the flow of fuel toward the normal workingv jet but to prevent any flow in the opposite direction, inparticular that of air under the effectof thesuction that is transmitted through the idling jetunder idling running conferential action diaphragm system of the carburetter with adjustable elastic means capable of urging, said system. in the direction corresponding to opening of the Valve, through which the fuel injectionpressure isregulated, provided that the throttle has moved beyond a predetermined opening position, said means being inoperative onsaid system for, lower degrees of'opening of said memher nd du in l n unhin According to a fourth feature, the chamber through which the external face; of the larger diaphragm is subjected to atmospheric pressure" has awall constituted by a deformable part (diaphragm) or a movable part (piston) connected to the throttle member control in such manner that when said member i suddenly moved from its closed position to itsopen position, the volume of said chamber is reduced, and, consequently, the pressure exerted on the larger membrane is temporarily increased, thus increasing the degree of opening of the valvewhich controls the fuel injection pressure.

Preferred embodiments of my invention will be hereinafter described with reference to the ac companying drawings, givenmerely by way of example and in which:

Fig. 1 shows, in diagrammatic axial section, an injector carburetter made according to the invention, fuel being supplied into the induction conduit on the downstream side of the throttle member;

Fig. 2 shows a modification of a part of this carburetter;

Fig. 3 shows a portion of such a carburettor in which fuel is supplied into the induction conduit on the upstream side of the throttle member.

The carburetter shown by the drawing includes duit 5 being controlledby means of a. valve 1, for

instance a ball valve, urged toward its seat by a spring 8. Valve 1 is controlled by a differential action dia hragm system, to be hereinafter described. The degree of opening of valve '1 determines the pressure under which fuel is injected into the carburetter.

Valve 1 is controlled by a rod 9 fixed to the central portion of a diaphragm which constitutes one of the walls of fuel chamber 6. On the other side of the diaphra m is provided a pneumatic chamber I I limited by a second diaphragm l2 parallel and coaxial with the first one but of greater area. Diaphragms Ill and I2 may be positively interconnected or else. as shown by Fig. 1, may mount on the inner face of the small diaphragm H] a central sleeve I3 in which is freely engaged a rod l4 fixed on the inner face of the large diaphragm, whereby a unidirectional connection is provided between these two diaph agms.

The pressure existing in the inlet of the carburetter. preferab y close to the throttled portion of choke t be 4, where the suction is maximum, is transmitted through a conduit [5 to pneumatic ch mber H. Eventually, this suction rricht be increased through the action of a multidifi'user, in the known manner.

The large diaphragm l2 also constitutes a portion of the wall of a chamber Hi which communicates with the atmosphere or with the carburetter air intake through a permanently open small orifice Ila and, preferably, through a second orifice I1 closed by a check valve (ball l8) which opens toward the inside of chamber l6.

Owing to the differential effect obtained throu h the two unequal diaphragms Ill and I2, valve 1 is caused to open more or less according to the value of the suction existing in the carburetter air intake, valve 1 being opened against the action of spring 8 and the fuel pressure in conduit 5 by the combined eifects of the suction in chamber H and the atmospheric pressure in chamber l6 acting upon the external face of diaphragm l2.

Fuel chamber 6 feeds, through a main jet IS, a conduit 2 leading to a jet 28, through which fuel is injected into conduit 29 during normal operation.

In conduit is provided a check valve consisting, for instance and as shown on Figs. 1 and 3, of a ball 2| urged toward its seat by its own weight or by a return spring or, as shown by Fig. 2, of a needle valve 2la controlled by a diaphragm 22 which divides a box 23 into two chambers one of which, 24, communicates freely with feed conduit 26 so as to be subjected to the fuel pressure existing in chamber 6 while the other, 25, is connected to the atmosphere through an orifice 26, this chamber containing a spring 2! which tends to apply needle valve 2la upon its seat. The effect thus obtained can be amplified by connecting chamber 25 not with the atmosphere but with choke tube 4 or with pneumatic chamber H, whereby needle valve 210. is

closed when chamber 6 is subjected to the action.

of a suction and is open when said chamber is subjected to the action of a pressure.

The normal working jet 28 is. provided opposite the inlet of a nozzle 38 which opens into the engine induction pipe 29 either on the downstream side of throttle 2 (Figs. 1 and 2) or on the upstream side thereof (Fig. 3). When this nozzle opens into conduit 29 on the downstream side of the throttle (Figs, 1 and 2) jet 28 is made free from the action 01 the suction existingin induction pipe 29, by being exposed to the action of atmospheric pressure. For this purpose, I may cut, in the inlet portion of nozzle 30, an aperture 3| through which atmospheric air can act and the area of which is substantially larger than the section of the neck portion of nozzle 38. When the nozzle opens into conduit 29 on the upstream side of throttle 2 (Fig. 3), I may proceed in the same manner but it is preferable to constitute the nozzle inlet by a chamber 3Ia which is connected with the atmosphere through one or several orifices 32, of small section, so that a suction of the same order of magnitude as that existing in choke tube 4 acts upon jet 28.

Fuel supply, when the engine is idling or running under very low loads, is ensured through an idling jet 35, branching off from feed conduit 23 on the downstream side of main jet l9 (Fig. 1) and in this case, only the cross section of main jet I9 is of significance to determine the fuel flow rate when running under load if jet 28 is of a section substantially larger than that of main jet I9.

Idling jet 35 may also (Fig. 2) be connected directly with fuel chamber 6 and in this case the respective outputs of both

jets

28 and 35 are added to each other to ensure the feed of the engtiine during normal working or Working under By suitably determining the dimensions of

lots

59 and 28, it is possible to obtain a whole range of solutions intermediate between those indicated in the first place and in the second place.

Conduit 34 opens into an idling conduit 36 which, preferably, communicates with the atmosphere through an orifice 31, either of constant section (Fig. 2) or adjustable by means of a needle valve 38 (Figs. 1 and 3).

The idling orifice 33, provided close to the edge of throttle 2, passes from the upstream to the downstream side thereof when, starting from the idling position, the throttle is slightly opened.

As shown by Fig. 1, the idling conduit 36 is connected through a calibrated orifice 39 with rid 12221; 39, into which opens the normal working e In the embodiment of Fig. 3, a calibrated ori fice 39a connects idling conduit 36 directly with the downstream side of the throttle.

Instead of acting through needle valve 38 on the orifice 3'! through which primary air is admitted to the idling conduit, in order to adjust the richness of the idling mixture (Figs. 1 and 3) I may have recourse to a needle valve ll) which adjusts the section of an auxiliary idling jet 4! through which a portion of said mixture is introduced into induction conduit 29. In this case, the idling air inlet 31 can be given either a constant (Fig. 2) or an adjustable section.

The device thus constituted works in the following manner. When the engine is idling, valve 1 is urged toward its seat by the pressure of the fuel acting in conduit 5 and, eventually by that 'of its spring 8, which tends to prevent the inflow of fuel into chamber 6. As the suction existing at this time in choke tube 4 and, consequently, in pneumatic chamber II, is practically zero, no effect is exerted on the system of diaphragms it and i2 that would tend to open valve l. On the contrary, the suction that exists on the downstream side of throttle 2 .is very high and is exerted, at least partly, upon idling jet 35, being transmitted through this jet to chamber 6. This action is transmitted to diaphragm is, and tends to move it toward the right hand side of Fig. 1

and thus to open valve-.1. ,The fuelsuppliedby;

jet 35 issthus'automatically-replaced inrchamr these conditions, by the unidirectional connection.

l3'l4 provided betweendiaphragms i and I2, which enables diaphragm i2 to'remain-in flxed positionwhen the small diaphragm Ill is thus sucked out. During idling-operation, valve 2;! (Figs. 1 and 3) or needle valve ZialFig. 2); prevents air from entering conduitiil through jet- 28; which inflow of air would prevent a-good working of the idling means.

When throttle2 is gradually opened,,a suction takes place in choke tube d and this suction, which increasesas the throttle is being. opened more and more and the engine speed is increas.-- inggis. transmitted through conduit E5 to pneumatic chamber II. The large diaphragm I2- is thus sucked in and moves toward the right hand side. of Fig. 1 and itpushes, through connection [3-44, the small diaphragm It in the same. direction, which causes, through rod 9, valve 1 to open. Fuel can therefore enter chamber 6-. When the pressure transmitted to chamber fi-from inlet conduit 5 becomes higher than the pressure that tends to apply valve 2! or needle valve 2 is upon its seat, fuel starts circulating in feed-conduit 2% either through jets i9 and 28 or through jets28and 35, according to the value of the suction existing in the choke tube d; of the carburetter, that is to say according to the rate of flow of air therethrough.

As the pressure under which fuelis supplied.

to conduit5 is, in most cases, very high, a relatively strong force. tends to keep valve 7 applied upon its seat and to this force is added that exerted on said valve 1 or on diaphragms It and [2 by return spring 3, which avoids accidental opening of valve 1 when the engine is stopped or idling. These forces, which oppose opening of valve I, may. in some cases, exaggerately delay the time at'which jet. l9 or'28is primed and thus disturb the operation of the carburetter.

In order to remedy this drawback, I providein chamber I6; which communicates with theatmosphere or with the intake of 'the carburetter, an elastic member, for instance an elastic'plate 42, which is located close to the external face of the large diaphragm i2, opposite the central portion thereof. One end of the plate, at43', is-flxed. in the lateral'wall of thecasin 44 in which diaphragms l8 and I2 are housed. and plate 42 is given a curvature such that, when it is left free,-

it bears upon a fingerli5 which projects from the 1 center of the external face of large diaphragm l2, with a tendency to push the latter toward. the right hand side of Fig. 1.

become higher than the antagonistic efiorts if it is desired to enrich the mixture supplied to the engine; atlow speeds of operation of said en ine.

In order to prevent the action of'elasticplate' 42 from being able to cause flooding-of the appae' ratus when the engine is stopped. or is running. at low speed. I provide means through which" the thrust of plate 42' is automatically eliminated when the throttling member or butterfly 2 comes. close to its idling position. For this purpose, I may, for instance, fit on the control spindlej of" The effect ofthis. thrustcan be adiusted'by means of a screw st the throttleran arm; ll v acting, upon a: rod .48, freely: slida-ble in a sleeve49, extending. through. the wall 44 of the diaphragm casing at aplace such that aflnger fixed-onsaidrodis located in' the plane of displacement'of the. free end of plate 42 and can push back this end towardtheleftihandside of Fig: 1 (out of contact with the. finger 45 of-diaphr'agm l2). when throttle 2 gets;

close -t0'.i1;$ idling position. Inthis wayv the thrust. ofelasticplate 42. ondiaphragms l2 and wand on obturator 1 cancelled; either wholly or partly. Advantageously:theiconnection between the arm 41 of the throttle valve and the finger that pushes "backor retains plate 42. is unidirectional..

For'this purpose body lcarries a. guiding sleeve 5| in'which is freelyengaged theend of rod 48,:

the :latterbeing provided withan'annular abut-= ment.52 cooperating with a spring 52a, engaged on: rod, AB- and' bearingupon fixed wall 44.

For the same purpose I may 'also (Fig. 1) con-- nect, either directly-or indirectly, chamber H with conduit 29 through a channel 6| opening,

for instance, on'the one-hand, into conduit-l5 and, onthe other hand, into the carburetter body l at a point 62 on the upstream side of throttle.

2,- when. the engineis idling, and on the down-- stream side of said throttle when the throttle is opened to a certain degree. Thus when the engine-is idling, orifices] is without action but, after a certain-opening of throttle 2, this orifice passes on the downstream'side thereof and the' suction existing in conduit 29 acts, to a certain.

degree, in conduit [5 and in chamber. ll, thus facilitating, displacement of diaphragm l2 towardthe right; and. therefore the opening of valve 1.

Whenthrottle :2 is suddenly opened (when the engine is to pick up) it maybenecessary or usefultemporarily to increase the richness of the mixture supplied to the engine. For this purpose I makeuse of 'a third diaphragm '53 or analogous member (piston), provided in chamber l6 and which is parallel and coaxial with large diaphragm E2. The external face of diaphragm 53 is subjected to the effect of atmosplieric pressure through an orifice 56. Rod 48,- above mentioned, carries an arm 48a the free end of which. is in contact, when the engine is throttle, with. the central portion of diaphragm 53 the external face of which is urged by a spring 5'5 bearing against the end wall of casing 44.

When throttle 2 is in its idling position, the diaphragm is pushed by arm 48a toward the left hand side of Fig. 1 and compresses spring 55. When the throttle is suddenly shifted from this position diaphragm 53 is pushed by spring55 toward the right hand side of Fig. 1. I thus obtain a reduction of the volume of chamber t6 and, consequently, a temporary increase of the pres.- sure existing in this chamber-since outflow of air from this chamber through hole Ila is impeded by the small dimensions of this hole while. air outflow through orifice I1 is prevented by the presence of check valveis; This pressure acts upon diaphragm I2 and therefore causes valve: 1 to open and fuel to be introduced into chamber 5 at a pressurehigher than-that existing during normal operation, when valve- 1 is" controlled solely by the suction acting-in pneumatic chamber ll. When throttle- 2 i's again- 7 tion in this chamber, which might have a detrimental action upon the degree of richness of the mixture.

In some cases it may be advantageous to supply the engine with a richer mixture when throttle 2 is wide open and with a leaner and more economical mixture when running under light load, for instance by reducing the suction existing in pneumatic chamber H so as thus to reduce the pressure of injection of the fuel and, therefore, the richness of the mixture.

For this purpose, chamber ll includes an auxiliary air inlet 56 provided with a needle valve 5! controlled by a diaphragm 58 or analogous element, subjected to the action of the suction existing in induction conduit 29 on the downstream side of throttle 2. This suction is transmitted through a conduit 59 connecting conduit 29 with the box which contains diaphragm 58. A spring 8t tends to apply needle valve 51 upon its seat. The other face of diaphragm 58 is subjected to atmospheric pressure or to the pressure existing in the air intake of the carburetter.

When the suction in induction conduit 29 reaches a predetermined value, diaphragm 58 is pulled toward the right hand side of Fig. 1 against the action of spring 60, which more or less opens air inlet 56 to reduce the suction existing in chamber II, and therefore to make the mixture fed to the engine leaner. A calibrated orifice B5, interposed between chamber Ii and air inlet 56, permits of limiting this effect.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said conduit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe leading into said chamber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion to reduce said section when the pressure in said chamber increases and vice-versa, a pneumatic chamber having at least one wall portion movable in response to pressure variations therein, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two wall portions so that an increase of this suction tends to increase said flow section and vice-versa, the second mentioned wall portion being of greater area than the first'one, a fuel nozzle opening into said induction conduit, communication, means interposed between said fuel chamber and said nozzle including a main jet arranged to be uninfluenced by suction variations in said conduit on the downstream side of said throttle, idling means forming a fuel outlet opening into said conduit and communication means connecting said idling fuel outlet and said fuel chamber to transmit the suction in said conduit on the downstream side of said throttle to said fuel 8" chamber to control said valve means, said communication means including an idling jet.

2. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said con duit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe leading into said chamber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion to reduce said flow section when the pressure in said chamber increases and vice-versa, a pneumatic chamber adjoining said fuel chamber so that said movable wall portion is common to both of said chambers, the wall of said pneumatic chamber that is located opposite said movable wall portion being itself movable, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two movable wall portions, the second mentioned wall portion being of larger area than the other one, a fuel nozzle opening into said induction conduit, communication means interposed between said fuel chamber and said nozzle including a main jet arranged to be uninfiuenced by suction variations in said conduit on the downstream side of said throttle, idling means forming a fuel outlet opening into said conduit and communication means connecting said idling fuel outlet and said fuel chamber to transmit the suction in said conduit on the downstream side of said throttle to said fuel chamber to control said valve means, said communication means including an idling jet.

3. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said conduit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe leading into said chamber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion to reduce said flow section when the pressure in said chamber increases and vice-versa, a pneumatic chamber adjoining said fuel chamber so that said movable wall portion is common to both of said chambers, the wall of said pneumatic chamber that is located opposite said movable wall portion being itself movable, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two movable wall portions, the second mentioned wall portion being of larger area than the other one, a fuel nozzle opening into said induction conduit on the downstream side of said throttle, communication means interposed between said fuel chamber and said nozzle including a main jet, the portion of said communication means between said jet and the outlet of said nozzle being provided with an orifice opening into the atmosphere and of a section larger than that of the neck of said nozzle, idling means forming a fuel outlet opening into said conduit and communication means connecting said idling fuel outlet and said fuel chamber to transmit the suction in said conduit on the downstream side of said throttle to said fuel chamber to control said valve means, said communication means including an idling jet.

4. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said conduit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe leading into said chamber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion, to reduce said flow section when the pressure in said chamber in creases and vice-versa, a pneumatic chamber adjoining said fuel chamber so that said movable Wall portion is common to both of said chambers, the wall of said pneumatic chamber that is located opposite. said movable wall portion being itself movable, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two movable wall portions, the second mentioned wall portion being of larger area than the other one, a fuel nozzle opening into said induction conduit on the upstream side of said throttle, communication means interposed between said fuel chamber and said nozzle including a main jet, the portion of said communication means between said jet and the outlet of said nozzle being provided with at least one small orifice opening into the atmosphere so as to subject said jet to a suction approximating that existing in said air intake, idling means forming a fuel outlet opening into said conduit and communication means connecting said idling fuel outlet and said fuel chamber to transmit the suction in said conduit on the downstream side of said throttle to said fuel chamber to control said valve means, said communication means ineluding an idling jet.

5. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said conduit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe leading into said cham ber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion to reduce said flow section when the pressure in said chamber increases and vice-versa, a pneumatic chamber adjoining said fuel chamber so that said movable wall portion is common to both of said chambers, the wall of said pneumatic chamber that is located opposite said movable wall portion being itself movable, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two movable wall portions, the second mentioned wall portion being of larger area than the other one, a fuel nozzle opening into said induction conduit, a main communication passage between said fuel chamber and said nozzle including a main jet arranged to be uninfluenced by suction variations in said conduit, idling means comprising a fuel outlet opening to said conduit, an idling passage branching off from said main passage and leading to said idling fuel outlet to transmit the suction in said conduit on the downstream side of the throttle valve to said fuel chamber to control said valve means, said idling passage including an idling jet, and valve means in said main communication passage, oi1' the downstream side of the branching of said:

idling passage, arranged to permit fluid flow from fuel chamber to nozzle and to prevent it in the opposite direction.

6. A carburetter according to claim 5 in which said last mentioned valve means consist of an automatic check valve.

7. A carburetter according to claim 5 in which said last mentioned valve means include a needle valve, a box, a diaphragm rigidly connected with said needle valve and dividing said box into two chambers, one of said chambers being connected with the atmosphere and the other with said main communication passage on the upstream side of said valve.

8. A carburetter which comprises, in combination, an induction conduit having an air intake, a throttle in said conduit, a venturi in said conduit, a fuel chamber having at least one wall portion movable in response to pressure variations therein, a fuel feed pipe'leading into said chamber adapted to be supplied with fuel under pressure, valve means for controlling the flow section from said pipe to said chamber, said valve means being operatively connected with said movable wall portion to reduce said flow section when the pressure in said chamber increases and vice-versa, a pneumatic chamber adjoining said fuel chamber so that said movable wall portion is common to both of said chambers, the wall of said pneumatic chamber that is located opposite said movable wall portion being itself movable, means for transmitting to said pneumatic chamber the suction existing in said venturi, means for mechanically interconnecting said two movable wall portions, the second mentioned wall portion being of larger area than the other one, a fuel nozzle opening into said induction conduit, communication means interposed between said fuel chamber and said nozzle including a main jet arranged to be uninfluenced by suction variations in said conduit on the downstream side of said throttle, idling means forming a fuel outlet opening into said conduit, com munication means connecting said idling fuel outlet and said fuel chamber to transmit the suction in said conduit on the downstream side of said throttle to said fuel chamber to control said valve means, said communication means including an idling jet, spring means for urging said large area movable wall portion in the direction tending to open said valve means, and means operatively connected with said throttle for preventing said spring means from acting on said large area movable wall portion as long as said throttle is opened below a given degree of opening.

GASTON GRIFFON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain June 16, 1937