US3367637A

US3367637A - Carburetor

Info

Publication number: US3367637A
Application number: US571645A
Authority: US
Inventors: Harry I Hazzard
Original assignee: Mcculloch Corp
Current assignee: Mcculloch Corp
Priority date: 1965-02-08
Filing date: 1966-08-10
Publication date: 1968-02-06
Anticipated expiration: 1985-02-06

Description

Feb 6, 1968 H l, HAZZARD I 3,367,637 I CARBURETOR original Filed Feb. a, 1965 3 she'etsheet 2 United States Patent O CARBURETOR Harry I. Hazzard, Los Angeles, Calif., assignor to Mc- Culloch Corporation, Los Angeles, Calif., a corporation of Wisconsin Continuation of application Ser. No. 431,091, Feb. 8, 1965. This application Aug. 10, 1966, Ser. No. 571,645 10 Claims. (Cl. 261-37) ABSTRACT F vTHE DISCLOSURE An improved carburetor including an emulsion chamber for premixing air and fuel prior to its transmission in an emulsion form to a venturi throat of the carburetor. Metering control means regulate the flow of air and fuel into the emulsion chamber throughout the full lrange of carburetor operation. This metering control means is connected by rigid lin-k means to a throttle valve in the induction passage of the carburetor. The metering control means is operably independent of ai-r flow through the induction passage and operably independent of means in the carburetor for regulating the flow of fuel to the emulsion chamber.

General summary of invention This application is a continuation of application Ser. No. 431,091, filed Feb. 8, 1965, and now abandoned.

This invention relates generally to charge forming devices for mixing a combustible mixture of fuel and air and relates more particularly to carburetors for internal com bustion engines.

While the invention has particular utility embodied in a diaphragm-type of carburetor for internal combustion engines used on chain saws and the like, and is shown and described thus embodied, it is to be understood that its utility is not confined thereto.

As is well known the provision of a carburetor that will meet the various operating conditions of chain saws involves certain problems and diiculties. One of these is the provision of the proper fuel mixture for all of various positions the chain saw may be ymoved to when in use and it is an object of the present invention to provide al carburetor that will function to provide the proper fuel to air mixture regardless of the position or attitude of the saw and engine.

Another object of the invention is to provide a carburetor of this character having a valve for controlling the mixture ratio of the fuel/air emulsion delivered to the induction passage for mixing with the air fiowing therethrough and thereby provide the proper fuel and air mixture delivered to the engine.

Still another object of the invention is to provide a carburetor of this character wherein the valve controlling the emulsion mixture ratio is a needle valve having an operative connection with the throttle valve.

A iiurthen object of the invention is to provide a oarburetor of this character wherein said needle valve regulates the air supply bled to the fuel for the fuel emulsion before it enters the induction passage of the device.

A still further object of the invention is to provide a carburetor of this character wherein said needle valve controls an air bleed orifice and fuel orifice for controlling the flow of fuel and air for the ratio of the fuel emulsion for idle, intermediate, and high speed engine operation, depending upon the position of the needle relative to said orifices.

Another object of the invention is to provide a carburetOr of this character wherein said needle valve is connected to the throttle valve by mechanical linkage.

Still another object lof the invention is to provide a 3,367,637 Patented Feb. 6, 1968 ICC carburetor of this character wherein, for any given position of the throttle valve, the mechanical linkage positions the needle valve in accordance with the throttle position so that there is just the correct amount of fuel and air for the fuel emulsion as well as the correct amount of said emulsion delivered to the induction passage for the amount of air the throttle valve allows to ow therethrough.

A further object of the invention is to provide a carburetor of this character wherein the transition from a suction lift to a venturi lift is smooth.

Still another object of the invention is to provide a carburetor of this character having high air velocity and hence good atomizing during idle operation.

A still further object of the invention is to provide a' carburetor of this character wherein the fuel in the diaphragm chamber is replaced at the same rate as it is used.

Another object of the invention is tol provide a carburetor of this character having a primer assembly included in the main body of the carburetor.

Still another object of the invention is to provide a carburetor of this character that is relatively simple in construction.

A further object of the invention is to provide a Carburetor of this character that is simple and effective in operation.

The chanaoteristics and advantages ofthe invention are further suiiiciently referred to in connection with the fol-` lowing detailed description of the accompanying draw-1 ings, which represent one embodiment. After considering this example skilled persons will understand that many variations may be made without departing from the principles disclosed and the employment of any structures, ar rangements or modes of operation are contemplated that are properly within the scope of the appended claims.

Referring to the drawings, which are for illustrative purposes only:

FIG. 1 is a top plan View of a carburetor embodying the present invention, a portion being broken away to show parts of the primer;

FIG. Z is an end View as seen from the air inlet end of the induction passage;

FIG. 3 is a sectional view taken on line 3--3` ofv FIG. l;

FIG. 4 is a sectional view taken on line 4 4 of FIG. 1;

FIG. 5 is a sectional view taken on line 5-5 of FIG. l;

FIG. 6 is a view taken from line 6 6 of FIG. 2;

FIG. 7 is a View taken from line 7-7 of FIG. 2;

FIG. 8 is a sectional view taken on line 8--8 of FIG. 1,

FIG. 9 is a schematic or diagrammatic view of the carburetor showing the various fluid passages and also showing the position of the needle valve when the throttle valve is in the idle position; and

FIG. 10 is a similar view showing the position of the needle valve when the throttle valve is in the substantially Wide open position.

Referring more particularly to the drawings, there is shown a carbuertor having a body, indicated generally at 15.

Carburetor body 15 includes a part that may be termed the body base 17 having an undersurface 16 that is in a single plane except for certain relieved portions and/or openings hereinafter described.

At the upper side of the body plate and integral therewith there is a tubular wall 18 defining an induction passage 19 having an air inlet 20 at one end. At the opposite end the induction passage has a downturned portion 21 for the outflow of air. A throttle valve 22 of the butterfly type is mounted on a throttle shaft 23 which, as shown in the drawings, extends horizontally across the induction passage intermediate its ends. Throttle shaft 23 is, of course, rotatable and is mounted in

bosses

24 and 25 at respective sides of the induction passage adjacent its forward end. The throttle valve 22 is secured to the throttle shaft in the usual well known manner, as by a screw 26, for example. l

The throttle valve is of the unbalanced type with the larger area at the upstream side of the throttle shaft so that air fiowing through the induction passage urges the throttle valve in the closing direction.

The carburetor body includes an integral boss 30 which includes a rearwardly and downwardly inclined passage 31, FIGS. 3, 9 and 10, which is open at its forward end. The air inlet end of the carburetor will be considered the forward end and the forward end of passage 31 is open.

An emulsion passage 32 has one end connected with the passage 31 intermediate its ends and said passage 32 extends upwardly and then downwardly as best shown in FIGS. 9 and l0. At the forward end of passage 31 there is an orifice fitting 34 (FIG. 3) having an orifice 35 extending longitudinally therethrough. This fitting is press fitted into the forward end of passage 31 and is thereby secured in position ahead of the point of connection of passage 32 with passage 31, said point of connection being a port 36. Rearwardly of the port 36 there is a second orifice fitting 37 having an orifice 38 therein, said orifices 3S and 38 being in axial alignment with each other. The orifice fittings 34 and 37 may be of any suitable material, one such material, especially for the orifice fittings 34, may be of metal or other suitable material.

A needle valve, indicated generally at 40, includes a tapered body portion 41 which extends into and through the

orifices

35 and 38. An outer end portion 42 of said needle valve 40 is externally threaded and provided with a diametrical slot 43 in its outer or free end for reception of a screwdriver blade or other instrument for rotating said valve. This theaded portion of the valve is threadably disposed in a tapped opening provided therefor in a swivel member 45 having end portions swivelingly or rotatably disposed in openings provided therefor in laterally arms 46 and 47 of a U-shaped bracket, indicated generally at 48, secured to an outwardly projecting end portion of the throttle shaft, said bracket being secured on the throttle shaft by a press fit or other suitable means. Thus, with this arangement, whenever the throttle valve is moved in the opening direction the body portion 41 of the needle valve 40 is moved outwardly of the

orifices

38 and 35 to thereby increase the effective size thereof.

At the opposite side of the induction passage the throttle shaft 23 has a part that projects outwardly of the lug 24 and there is provided thereon a throttle lever, indicated generally at 50, having an arm 51 with an opening therethrough in which is received the outwardly extending portion of the throttle shaft. The throttle lever is loosely notch 53 therein for reception of a pin 54 secured in an opening provided therefor in the outwardly extending portion of the throttle shaft, said notch dividing the free end portion 52 and leaving

parts

55 and 56 at opposite sides to define the sides of the notch. The notch 53 is of greater width than the diameter of the pin 54 so that there is a lost motion connection between said pin and the

parts

55 and 56 of the throttle lever.

The throttle lever is secured on the outwardly extending portion of the throttle shaft by means of a clip 58 which has a notch therein for reception of the adjacent portion of the throttle shaft, said clip being disposed at the outer side of the lever portion 51 of the throttle lever. Clip 58 is secured to the carburetor body by means of a screw 59 received in an opening provided therefor in said clip and a tapped opening also provided therefor in a boss 60 integral with the carburetor body. On screw 59 there is also a bracket 61 having an inturned part 62 engageable by a portion of the throttle lever to limit movement of said lever in the closing direction.

A coil spring 64 is disposed on the outwardly extending portion of the throttle shaft between the clip 58 and the pin 54. One end of said spring, end 66, is hooked onto the throttle lever to urge same in the throttle valve closing direction, the opposite end of said spring, end 67, is hooked onto said pin 54.

The throttle shaft is, of course, connected to any suitable well known mechanism for actuating same and when said lever is urged to the idling position the spring 64 urges the throttle shaft in a direction to open the throttle valve a limited amount determined by the engagement of said pin with part 56 of the free end portion of the throttle lever. From a set governing speed a higher speed will increase the suction and close the throttle against the spring 64. A lower speed means lower suction and the spring opens the throttle to increase the engine speed. Thus there is an automatic positioning of the throttle valve which provides an idle governing arrangement.

At the side of the carburetor body having the bracket 48, there are a pair of

integral bosses

70 and 71 having tapped openings therein. The tapped opening in the boss 70 is provided with an idle adjusting screw 72 having a head 73 with a slot therein for the blade of a screwdriver or other instrument for adjusting said screw, there also being a spring 74 on said screw reacting between said head and the boss 70. The free end of screw 72 is adapted to be engaged by a laterally turned end portion 76 of the bracket 48 to limit the movement of the throttle shaft in the closing direction and provide idle adjustment means. Boss 71 is provided with a screw 78 having a head 79 thereon with a slot therein for reception of an adjusting tool, there also being a spring 80 on said screw between the head thereof and the boss 71 thereof. The laterally turned end portion 76 of the bracket 48 is adapted to engage the free end of screw 78 which thereby limits opening movement of the throttle shaft and hence the throttle valve.

The underside of the base 17 is provided with a fuel recess 84 (FIG. 9) which will be termed a fuel chamber. Chamber 84 has an outlet port 85 leading to an outlet passage 86 which is connected to the upstream end of passage 31 upstream of the orifice fitting 37 and hence the orifice 38.

Fuel is supplied to the chamber 84 by means of a pulse pump, indicated generally at 88, of well known character, said pump having a fuel chamber 89 from which an outlet fuel passage 90 extends to a fuel inlet 96 for the chamber 84, said fuel inlet being controlled by a needle valve 97 connected to one end of a lever 98 pivoted at 99 and having an arm portion 100 in engagement with a diaphragm portion 101 which forms one wall of the chamber 84. There is also a spring 102 in a recess provided therefor in the base 17 which urges the lever 98 in a direction to effect closing of the inlet 96 by the valve 97. At the opposite side of the diaphragm portion 101 there is a chamber 105 vented to atmosphere by means of a vent port 106 (FIG. 4). This mechanism controls the fiow of fuel and as fuel is taken from chamber 84 the pressure in said chamber drops sufficiently so that atmospheric pressure on the atmospheric side of diaphragm 101 actuates the lever 98 so that valve 97 opens to permit additional fuel to enter chamber 84. There is a check valve 108 in the fuel line 90 from the pump chamber 89 to the chamber 84 which permits fuel to ow to said chamber 84 but prevents back-flow of fuel. f

One side of the pulse pump fuel chamber 89 is defined by a diaphragm 110 and there is a pulse chamber 111 at the opposite side of said diaphragm, said pulse chamber being connected in the usual manner by a conduit 112 with a source of pulse impulses generated by the engine. Fuel is supplied to the pulse pump by means of a conduit 114 which is provided with a check valvel 115 which permits fuel to fiow to chamber 89 of said pulse pump but prevents reverse flow of fuel. There is also a filter 116 in said fuel line 114 upstream of the charnber 89.

Diaphragm 101 provides one side of the chamber 84 and there is a reinforcing member 120 (FIG. 4) secured to the top side of said diaphragm, said member having a nub 121 against which curved free end portion 122 of the fuel control lever 98 abuts.

There is a secondary diaphragm indicated generally at 125 of suitable material, such as glass cloth and Teon, which provides long flexing life and retains its resiliency. A portion of this diaphragm provides the pump diaphragm 110 and the check valves 115 and 108, comprising tongues cut from the secondary diaphragm and adapted to flex. The diaphragm 101 may be made from suitable rubber-like material, such as neoprene, which is substantially impervious to any liquid fuel it may come in contact with. The gasket 126 is also made from such material.

The diaphragms are clamped between the base 17 of the body of the carburetor and a plate 130, there being screws for securing the parts together, one such screw being shown as 131, in FIG. 3.

The side of the plate facing the base 17 is provided with a recess 133 which denes the chamber 105 at the underside of the diaphragm 101. This plate also has an elongated opening 134 which is rounded downwardly and outwardly 4about its periphery, as at 135, the larger size or area of the opening 134 being in communication, through an opening provided therefor in the diaphragm, with the lower end portion 21 of the induction passage, said lower end portion being elongated to correspond with the opening 134 in the plate 130 and said opening 134 of said plate defining a venturi throat 136. The lower or outer end of said opening 134 being in register with the corresponding opening 137 in an adjacent portion 138 of the engine, which opening 137 flares outwardly as at 139 to provide the downstream portion of the venturi.

At the lower end of the downwardly extending portion of passage 32 there is a check valve 141 and the adjacent passage portion connects with a passage 142 which leads to the main fuel discharge nozzle 143 discharging into the throat of the Venturi. Check valve 141 permits fuel to flow to the main fuel nozzle but prevents reverse flow through said passage 32, it being noted that valve 141 is in the plate 130 and comprises a disc of suitable plastic or metal held in position by a spider 145 (FIG. 5).

In operation fuel fiows from a. fuel tank, not shown, by way of conduit 114, to the wet side of the pulse pump, that is, chamber 89 of said pump. The fuel pump forces the fuel at two or three pounds per square inch gauge to the fuel inlet needle 97 located in the main carburetor casting. Flowing past the fuel inlet n-eedle,

the fuel enters the wet side of the fuel control arrangement, that is the fuel enters cha-mber 84. The weight of the fuel causes the diaphragm 101 to move downwardly from the fuel inlet lever and spring 102 effec-ts closing of the fuel inlet valve 97 to stop the flow of fluid or fuel into the chamber 84.

lThe main metering passage 31 contains a fuel metering orifice 38 and the air bleed orifice 35, the main metering needle 40 controlling the effective sizes of said orifices as the throttle shaft is rotated in opening or closing direction.

Fuel enters the space 150 between the orifice fittings 34 and 37 by way of the orifice 38 and air is drawn into said space or chamber 150 through the metering orifice 35. The fuel and air entering said chamber 150 are mixed into an emulsion and flow through the passage 32 to the main fuel nozzle 143 after passing the check valve 141.

Whenl the engine is idling the flow of fuel and air from the main discharge nozzle 143 is effected by the depressed pressure condition between the throttle and the engine. As the throttle is opened the pressure drop between the throttle valve and the engine gradually reduces but the air speed through the venturi increases to cause a pressure drop at the main nozzle 143. The transition from the suction lift to the venturi lift is smooth and is not discernible. l

As the throttle valve is moved in the opening or closing direction the amount of air allowed to iiow through the induction passage is varied accordingly. At the same time the needle valve 40 is moved outwardly orinwardly of the

orifices

35 and 38 and because of the tapered body portion 41 in said orifices the amount of fuel and air admitted to the mixing or emulsion chamber is varied accordingly. The emulsion from chamber 150 flows through the passage 32 to the main fuel nozzle and hence the proper fuel mixture is provided in accordance with the requirements of the engine for the various throttle positions.

The carburetor also includes a primer, indicated generally at 160, said primer having a bore 161 defined by a wall 162. One end of the primer bore, end 163, is open, while the opposite end is closed by a wall 164.

Within the bore 161 is disposed a plunger 165, having a forward projection 166 which engages the adjacent end' of a valve cage 167 of the outlet body and needle assembly, indicated generally at 168. Cage 167 is of smaller diameter than the diameter of the bore 161 and is provided With an annular ange 169 slidably engageable with the wall of the bore 161. At the inner side of ange 169 there is a seal 170 and at the opposite side between said flange and a shoulder 171 about the projecting end portion 166, there is a coil spring 172 urging the cage 167 and plunger 165 apart and retaining the cage at the inner end of bore 161.

The cage 167 is hollow and is provided with a bore 173 in which is slidably disposed a needle valve having a relieved part 174 and a needle point 175 adapted to seat on a shoulder 176 adjacent the outer end of said piston. At its outer end cage 167 has an end wall in which is provided an orifice 178. Valve 174 is urged to the closed position; that is, into engagement with said shoulder, by means of a spring 179.

When the primer is inoperative the parts thereof are in the positions shown in FIGS. 9 and 10, the parts being shown in their positions at the end of the primer discharge stroke.

Primer fuel is drawn from any suitable part of the fuel system, it being shown as being drawn through a conduit 182 connected with the pulse chamber v89, although in the commercial embodiment of the carburetor primer fuel is drawn from the main fuel passage, which is connected to the fuel pump. The outlet end of conduit 182 is connected to the bore 161 by a port 183 which is located adjacent the inner end of the plunger 165 when the latter is in its outer, inoperative position. At this time the spring 172 keeps the plunger at its outer or at rest position. A check valve 185 is disposed in the conduit 182 and permits fuel to flow into the bore 161 of the primer but prevents reverse iiow through said conduit 182.

When the primer plunger is pushed inwardly the outlet check valve 174 is opened and fuel is expelled into the carburetor throat through this valve and the primer discharge passage 188. When the primer plunger is released the outlet valve 174 is closed by its spring 179, the plunger is moved outwardly to its normal position of rest by spring 172, and the check valve 185 opens and permits the primer cylinder or bore 161 between the plunger 165 and the piston 167 to lill in preparation for a repeat cycle.

The valve 185 as shown in FIG. 4 is of tubular construction and comprises a cylindrical portion 189 and a exible tip portion 190 which has a relatively -thin wall. Fuel will flow through the valve 185, including the portion 190, but when there is pressure on the outside of the tip 190 the Walls thereof collapse and close the opening 7 through said tip portion, thereby preventing a reverse fiow of fluid.

The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and larrangement of the paits of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangement hereinbefore described being merely by way of example, and I do not wish to be restricted to the specific forms shown or uses mentioned except as defined in the accompanying claims, wherein various portions have been separated for clarity of reading and not for emphasis.

What is claimed is: 1. In combination in a carburetor fuel reservoir means; wall means forming an emulsion chamber; an air inlet and a fuel inlet to said chamber; an emulsion outlet leading from said chamber; metering control means for metering the fiow of air through said air inlet and the flow of fuel through said fuel inlet so that predetermined proportions of air and fuel are maintained through said emulsion outlet during full range of carburetor operation;

diaphragm means operable to regulate the fiow of fuel to said fuel inlet independent of the orientation of said reservoir means;

an induction passage including a venturi throat;

a throttle valve in said induction passage for controlling air fiow therethrough;

means defining an emulsion passage leading from said emulsion outlet and having a terminus discharging into said venturi throat;

said throttle valve being positioned upstream of said venturi throat and said emulsion passage terminus; and

rigid linkage means positively interconnecting said metering control means and said throttle valve and operable to cause operation of said control means in response to movement of said throttle valve;

said metering control means including valve means connected with said rigid linkage means and mounted for valving movement solely in response to movement of said throttle valve, said valve means being operable to valve air flowing through said air inlet and fuel flowing through said fuel inlet.

2. A charge forming apparatus for a carburetor comprising:

fuel reservoir means;

emulsion forming, chamber means;

an emulsion outlet leading from said chamber means;

first metering passage means providing communication between said fuel reservoir means and said chamber means;

second metering passage means providing communication between said chamber means and the atmosphere; said second metering passage means being displaced from a fuel body contained within said fuel reservoir means when said fuel body is there disposed;

metering control means for simultaneously varying, in a continuously progressive fashion, the entire fiow capacity of each of said first and second metering passage means continuously throughout the operation of said apparatus, from idle through full open throttle conditions, while permitting flow through each of said passage means;

diaphragm means operable to regulate the flow of fuel to said first metering passage means independent of the orientation of said reservoir means;

an induction passage including a venturi throat;

said metering control means including valve means connected with said rigid linkage means and mounted for valving movement solely in response to movement of said throttle valve, said valve means being operable to valve air flowing through said second metering passage means and fuel flowing through said first metering passage means.

3. A charge forming apparatus for a carburetor comprising:

fuel reservoir means;

emulsion forming, chamber means;

said chamber means being displaced from a fuel body contained within said fuel reservoir means when said fuel body is there disposed;

an emulsion outlet leading from said chamber means;

second metering passage means providing communication between said chamber means and the atmosphere and continuously open from idle through full open throttle conditions of said carburetor;

said second metering passage means being displaced from a fuel body contained within said fuel resrevoir means when said fuel body is there disposed;

said second metering passage means defining the sole communication between the atmosphere and said chamber means;

metering control means for simultaneously varying the entire fiow capacity of each of said first and second metering passage means continuously throughout the operation o-f said carburetor from idle through full open throttle conditions;

diaphragm means opera-ble to regulate the fiow of fuel to said first metering passage means independent of the orietation of said reservoir means;

an induction passage including a venturi throat;

rigid linkage means positively interconnecting said metering control means and said throttle valve and operable to cause operation of said controls means in response to movement of said throttle valve;

said metering control means including valve means connected with said rigid linkage means and mounted for valving movement solely in response to movement of said'throttle valve, said valve means being operable to valve air flowing through said second metering passage means and fuel flowing through said first metering passage means.

4. A charge forming apparatus for a carburetor comprising:

fuel reservoir means;

emulsion for-ming, chamber means;

an emulsion outlet, passage means leading from said chamber means;

second metering passage means providing communication between said chamber means and the Iatmosphere and continuously open from idle through full open throttle conditions of said carburetor;

said second. metering passage means being displaced from a fuel body contained within said fuel reservoir means when said fuel body is there disposed;

said chamber means, when said apparatus is oriented to position said second passage means above said fuel reservoir means, being disposed above said fuel reservoir means, with said fuel -reesrvoir means being operable to transmit fuel to said chamber means;

metering control means for simultaneously, and in a i continuously progressive fashion, varying the entire flow capacity of each of .said first and second metering passage means continuously throughout the operation of said carburetor from idle through full open throttle conditions;

diaphragm means operable to regulate the ow of fuel to said first metering passage means independent of the orientation of said reservoir means;

said first and second passage means each having coaxially aligned metering orifices dis-charging in mutually opposed directions into said chamber lmeans with said orifices each being displaced from a fuel body contained within said reservoir means, when said fuel body is there disposed, and with said fuel reservoir means being disposed generally between said diaphragm means and said orifices;

said emulsion outlet passage means communicating with said chamber -means generally between said first and second passage means and said emulsion outlet passage means being displaced from a fuel body contained Within said reservoir means when said fuel body is there disposed;

said emulsion outlet passage means having a generally V-shaped portion including one leg thereof extending generally away from said chamber means and said diaphragm means and another leg including a check valve preventing flow to said chamber means and extending generally toward the plane of said diaphragm means; Y

an induction passage including a venturi throat;

a throttle valve in .said induction passage for controlling air ow therethrough;

said emulsion outlet passage means defining an emulsion passage leading from said emulsion forming chamber means and having a terminus discharging into said venturi throat;

rigid linkage means positively interconnecting said metering control means and said throttle valve and operable to cause operation of said cont-rol means in response to movement of said throttle valve;

said metering control means including valve means connected with said rigid linkage means and mounted for valving movement solely in response to movement of said throttle va-lve, said valve means being operable to valve air fiowing through said second metering passage means and fuel flowing through said first metering passage means.

5. In charge forming means;

a body having an induction passage with an air inlet,

a venturi throat, and an air-fuel mixture outlet;

means defining an emulsion chamber;

an emulsion passageway leading from said chamber and terminating in a main fuel discharge nozzle dis- 10 chai-ging into said venturi throat of said induction passage;

means dening a fuel orifice for fuel owing into said emulsion chamber;

means defining an -air orifice for air flowing into said emulsion chamber;

metering control means for varying the effective sizes of said fuel and air orifices;

a throttle valve in said induction passage for controlling air ow therethrough, said throttle valve being positioned upstream of said venturi throat and said main fuel discharge nozzle;

rigid linkage means positively and operably connecting together said metering control means and said throttle valve whereby movements of said throttle valve effect corresponding movements of said metering control means;

a check valve controlling the liow of emulsion in the emulsion passageway, said Valve permitting the ow of emulsion through said emulsion passageway to said induction passage but preventing reverse flow of emulsion in said emulsion passageway; and

diaphragm means for controlling the supply of fuel to said fuel orifice independent of the orientation of said charge-forming means;

said metering control means including valve means connected with said rigid linkage means and mounted for valving movement solely in response to movement of said throttle valve, said valve means being operable to valve air flowing through said air orifice Iand fuel owing through said fuel orifice.

`6. The invention defined by claim 5 including primer means for reception of fuel from a main fuel passage and for delivering priming fuel to the induction passage independently of said metering control means, wherein said primer means comprises a flow channel bypass around said metering c-ontrol means, said bypass defining a cylindrical bore, with said primer means including:

a plunger slidably disposed in said bore;

an outlet valve assembly including a valve cage of smaller diameter than the diameter of said bore;

an annular liange on said cage;

spring means between said flange and the inner end of said plunger;

a valve seat in said cage;

a valve within said cage adapted to seat on said valve seat;

and spring means urging said valve toward said seat.

7. The invention defined by claim 5:

wherein said orifices are in axial alignment and disposed at opposite ends of said emulsion chamber; and

wherein said valve means comprises a single movable tapered metering needle valve operably disposed in said orifices for simultaneously and proportionally controlling said orifices, and having connecting means connecting same wtih said throttle valve.

S. The invention defined by claim 5:

wherein the body includes a base having an opening therein which is the terminal end of that part of the induction passage in said body; and

wherein said invention includes a plate attached to said base, said plate having an opening therein registering with the opening in the base, the opening in said plate having rounded edges from the inner side of the plate to the outer .side so that the opening in said plate is of greater area at its inner end than at its outer end to thereby form said venturi throat.

9. The invention defined by claim 5:

wherein sai-d valve means for varying the effective sizes of the fuel and air orifices comprises a single tapered metering needle valve; and

wherein said throttle valve includes a throttle shaft extending through the induction passage, and

1'1 a buttery valve member operably secured to said shaft; .said rigid linkage means including: a bracket connected to said shaft, and a swivel member pivotally mounted to said bracket, one end of said metering needle valve being operably connected to said swivel member.

10. In charge forming means:

a body having an induction passage with an air inlet and an air-fuel mixture outlet;

means defining an emulsion chamber;

an emulsion passageway leading from said chamber and terminating in a main fuel discharge nozzle discharging into said induction passage;

means defining a fuel orice for fuel flow into said emulsion chamber;

means defining yan air orice for air ow into said emulsion chamber;

metering control means for varying the effective sizes of said fuel and air orices;

a throttle shaft in said induction passage supporting a buttery valve member for controlling air flow therethrough;

said orifices being in axial alignment and disposed at opposite ends of said emulsion chamber;

said metering control means comprising a movable tapered metering needle valve operably disposed in said orices;

a bracket connected to said shaft; and

a swivel member pivotally mounted to said bracket;

said metering needle valve having an externally threaded outer end portion and said swivel member having a tapped bore therein threadably receiving said threaded end portion of said needle valve.

References Cited UNITED STATES PATENTS 696,146 3/ 1902 Riotte et al. 1,552,994 9/ 1925 Lindeman 222--341 1,985,712 12/1934 Ball et al. 261-51 1,991,408 2/1935 Morrow et al 222-341 2,159,173 5/1949 Mennesson 261-65 2,679,835 6/1954 Thorner 261-69 X 2,796,838 6/1957 Phillips. 2,887,309 5/1959 Raynor 261-50 2,918,046 12/ 1959 Teagarden. 3,003,754 10/1961 Phillips 261-50 X 3,065,957 11 /1962 Phillips. 3,072,390 1/ 1963 Phillips. 3,085,791 4/1963 Phillips. 3,198,497 8/1965 Mennesson 261-50 3,201,096 8/1965 Bar-r.

FOREIGN PATENTS 236,169 10/ 1964 Austria.

RONALD R. WEAVER, Prima/'y Examiner.