US3215413A

US3215413A - Carburetor

Info

Publication number: US3215413A
Application number: US146896A
Authority: US
Inventors: Jesse L Szwargulski; Jr Ralph E Kalert
Original assignee: ACF Industries Inc
Current assignee: ACF Industries Inc
Priority date: 1961-10-23
Filing date: 1961-10-23
Publication date: 1965-11-02
Anticipated expiration: 1982-11-02

Description

NOV- 2, 1965 J. L. SZWARGULSKI ETAL 3,215,413

JESSE L. SZWARGULSKI BY RALPH E. KALERT AGENT NOV- 2, 1955 J. L. szwARGULsKl ETAL 3,215,413

CARBURETOR 2 Sheets-Sheet 2 Filed Oct. 23. 1961 INVENToRs JESSE L. SZWARGULSKI RALPH E. KALERT AGENT United States Patent O 3,215,413 CARBURETOR Jesse L. Szwargulski, Florissant, Mo., and Ralph E. Kalert,

Jr., Granite City, Ill., assignors to ACF Industries, Incorporated, New York, NX., a corporation of New Jersey Filed Oct. 23, 1961, Ser. No. 146,896 3 Claims. (Cl. 261-41) This invention is directed to a carburetor for an internal combustion engine and particularly to novel structures incorporating fuel circuits for such a carburetor.

An approach to cost reduction in the fabrication of a carburetor for an internal combustion engine is in the use of a single casting to provide the several fuel circuits and the air-fuel mixture conduit for the carburetor. One such design utilizes a single casting having a depending portion to be enclosed within the fuel bowl of the carburetor and includes the necessary fuel circuits provided by conduits and passages cast and drilled in the casting. The single casting also incorporates the air horn, the fuel -bowl cover, the mixture conduit and the throttle valve support. In fabricating a carburetor in which cost reduction `is an essential goal, it is also possible to eliminate an excessive number of levers and other parts which have been used in the past.

Accordingly, it is an object of this invention to provide a novel carburetor which can be fabricated at a minimum expense and having a minimum number of parts.

It is another object of this invention to provide a novel carburetor for an internal combustion engine formed of a single casting in which the fuel circuits of the carburetor are easily formed with a minimum number of parts.

It is another object of this invention to provide a novel carburetor structure in which the carburetor consists essentially of a single casting and a fuel bowl and having a minimum number of working parts, in order to reduce the cost of fabrication.

The invention is in a carburetor in which the object is to provide cost reduction in its fabrication. For this purpose the carburetor is designed with all of its essential features incorporated in a single body casting. The body is provided with a depending portion enclosed within the fuel bowl of the carburetor. Attached to this depending portion, which also forms the cover of the fuel bowl, there is formed the main and idle fuel circuits, the accelerating fuel circuits, as well as having supported therefrom the float and inlet valve for the carburetor. The assemblage of parts is simplied so that the main fuel circuit includes a fuel well having an adjustable jet which is varied by the movement of a metering rod through the jet. lThe means for adjustably positioning the metering rod is a vacuum motor formed in alignment with the metering rod and attached directly thereto. A further simplification includes the utilization of the main fuel nozzle for the passage therethrough of accelerating fuel upon the opening of the throttle by manual operation. The idle system and main fuel system are dependent such that fuel ilow through the main fuel system maintains a washing action on the idle tube and thus prevents the forming of fuel vapors around the tube which would delay action of the idle circuit. Both the throttle and choke valves are mounted within the single casting as well as the operating levers for the a-ccelerating pump.

ice

The design of the carburetor is such as to provide a cornpact and readily accessible carburetor to provide ease of replacement and repair.

FIGURE l is a plan view of a carburetor embodying the novel features of this invention.

FIGURE 2 is substantially a longitudinal sectional view of the carburetor of FIGURE l, and shown mounted on an engine manifold with an -air filter partly in section.

FIGURE 3 is a partial sectional view of the carburetor of FIGURE l and along section lines 3 3 of FIG- URE l.

FIGURE 4 is an enlarged sectional view of a portion of the structure of FIGURE 3 illustrating further features of the invention.

FIGURE 5 is a sectional view of a portion of the carburetor of FIGURES l and 2 illustrating schematically the idle circuit.

FIGURE 6 is a further sectional view Iof the carburetor and showing a part of the accelerating circuits of FIG- URES 1 and 2.

The carburetor shown in FIGURES 1 and 2 consists essentially of a single casting 10, which is formed with a fuel and air mixture conduit 12 and a fuel bowl cover portion 14, from which is integrally formed a depending structure formed with an accelerating pump cylinder 16, an accelerating fuel passage 18 yand a fuel well structure 2d. As shown, the mixture conduit 12 is arranged and aligned vertically during operation and is connected by a flange 13 to the intake manifold M of an internal cornbustion engine E. In the lower part of the conduit 12 there is rotatably mounted a throttle valve 22 fixed to a throttle shaft 24 journaled in appropriately aligned apertures of the body casting 10. In the upper portion of the `fuel-air mixture Aconduit 12 there is similarly mounted for rotational movement an unbalanced choke valve 26 fixed to a choke valve shaft 28, which is also journaled in aligned apertures through the 'body casting 10. To the top of the mixture conduit 12 is connected an air filter 29, partially shown in section in FIGURE 2. Between the upper and lower portions of the mixture conduit 12 is formed a venturi or air flow restricting surface portion 30. A small booster venturi 32 is formed integrally with the body casting it) and has an inner venturi surface 34 coaxially aligned with the mixture conduit l12 and the primary venturi surface 30.

A plastic fuel bowl 36 is fixed beneath the fuel bowl cover 14 and is held with its rim tightly against a gasket 38 fitted between the rim of the fuel lbowl 36 and matching portions of the fuel bowl cover 14. A float structure 40 Iis fixed to a float lever 41 which is pivotally mounted from pin 42 journaled in a depending portion of the fuel bowl cover portion 14. A lever arm 43 of the oat lever 41 abuts the lower end of a needle valve 44 having an upper tapered end extending into a resilient valve seat 46. Valve 44 and seat 46 control fuel flow into the inlet 47 to the fuel bowl 36. Inlet 47 is an integral part of casting 10. A fitting may be threaded into inlet 47 to conne-ct the carburetor to a fuel line 48. Fuel is forced by a pump from a fuel tank 52 (both schematically shown) through the fuel line 48 and into the carburetor inlet 47. With the fuel level in bowl 36 low, the float 40 is lowered and lever arm 43 allows valve 44 to be pressed -by fuel pressure and by gravity to an open position. Fuel flows into the bowl 36 `and when it reaches a predetermined level, the float lever 43 presses upwardly against the needle valve 44 to close the inlet to the fuel bowl.

The lower end of the fuel well 20 is closed by a threaded fitting 56 having a central orifice 69 therethrough (FIGURE 4), which is carefully formed to provide a metering jet for the fiow of fuel from the fuel bowl 36 to the mixture conduit 12. The upper end of the fuel well 20 intercepts a cross fuel passage 58 drilled downwardly into the secondary venturi structure 32. A nozzle fitting 60 is press-fitted into the end of passage 58 and has one end thereof extending into the Center of the secondary venturi surface 34. Press-fitted within the Well 20 is a fuel emulsion tube 62 having apertures 63 therethrough along its length, as shown in FIGURE 4.

A metering pin 66 is suspended within the fuel well 20. Pin :66 has an end 68 formed with varying thicknesses. The formed end 68 is positioned within the main fuel jet orifice 69 for operation in response to engine requirements. Flow of fuel through the main jet 56 is controlled by the metering rod 66 and in accordance with that portion of the formed end 68, which is positioned within the jet 56, as described below. The metering rod 66 is supported from a retainer 70 in which the upper end of rod 66 is frictionally engaged. The details of the retainer 70 and rod 66 are the subject of a copending application of Jesse L. Szwargulski, Serial No. 131,175, filed on August 14, 1961, now Patent No. 3,136,827.

A light spring 78 is positioned within a bore 77 between a shoulder portion 79 of the body casting 10 and the upper flanged end of the retainer 70. Spring 78 is of a strength to merely overcome the weight of retainer 70 and the rod 66 and to thus always bias the upper surface of retainer 70 against a diaphragm 80 which is sealed in an air tight manner at its peripheral edge between a shoulder 81 of the body casting and a fitting 82 pressed into a matching bore 84 of the body casting. Diaphragm 80 extends across a cavity 86 which is formed from a depression in the bottom of bore 84 and fitting 82. On the upper side of diaphragm 80, opposite to the side against which the retainer 70 is biased, is positioned a second retainer structure 88 similar in construction to retainer 70. A spring 90 is positioned between the top of a central bore 91 of fitting 82 and the lower flanged surface of the retainer 88 to bias the retainer 88 and diaphragm 80 in a downward position, as shown in FIGURES 2 and 4, for example.

Bores

91 and 77 are axially aligned but off to one side of the axis of the cylindrical well 20. This suspends metering rod 66 to one side of the well axis and biases the rod end 68 eccentrically within jet orifice 69 against the side of the jet fitting 56. This provides a consistent fiow of fuel through orifice 69 for any position of the metering rod 66.

The bore 91 is connected by a cross passage 92 to an annular passage 93 formed in the peripheral surface of the fitting 82. As shown in FIGURE 3, a passage 94 is formed through the body casting 10 to the flange portion 13 of the carburetor and opens at 95 into the mixing conduit and manifold M below or downstream of the throttle 22. In this manner, passage 94 connects the portion of cavity 86 above the diaphragm 80 to the manifold pressure of the engine.

A passage 96 (FIGURE 2) is formed between the mixing conduit 12 from a region between the choke valve 26 and the throttle valve 22 to extend downwardly into the upper portion of well 20. Within the passage 96 is pressfitted a restriction element 98 for metering air fiow through passage 96 into the well 20.

As shown in FIGURE 4, a second well structure is Aformed from a bore 101 in casting 10 to provide a second well` 103 adjacent to the well 20. The bottom of Well 103 is partially closed by a fitting 105 having an axial passage 107 therethrough of a predetermined cross section. Passage 107 forms a fixed metering jet for the fiow of fuel from the fuel bowl 36 upwardly into Well 103. A cross passage 109 connects well 103 with we1l20. Flow 4 of fuel to the main nozzle is from the fuel bowl 36 through both the fixed jet 107 and the adjustable jet 69 and the cross passage 109 connecting the two fuel wells. Fuel then flows upwardly through the emulsion tube 62 into the main fuel passage 58 and out the nozzle 60.

For an engine of 195.6 cu. in. displacement, it was -urerp umurrurur e qlr/u Hem poialodo 69 ist gen1 puno; eter of 0.089. At the same time, the fixed jet 107 had a diameter of 0.03 8, while the metering rod end 68 varied from a minimum diameter of 0.058 at 67 to 0.074" maximum diameter. These values are examples only and are not limiting.

Mounted within the cylindrical recess 16 formed in body casting 10 is a pump piston 100 (FIGURE 2), which is connected to a pump piston rod 102. A spring 104 is fitted between `the upper end of the pump cylinder 16 and the piston 100. The lower end of the pump cylinder 16 is closed by a fitting 106 having a central aperture 108 therethrough above which, biased by gravity, is a ball check valve 110. A fuel passage 112 extends between the pump cylinder 16 and the cylindrical passage 18 formed in the body casing 10. lPassage 112 permits fuel fiow into a fitting 114 closing the lower end of cylindrical passage 18 and having at its upper end a valve seat in which the pointed end of a gravity biased check valve 116 is fitted. The cylindrical passage 18 extends upwardly and intercepts the main fuel passage 58, at which point a closure fitting 118 is fixed. Fitting 118 forms an annular channel 117 with passage 58. Channel 117 is connected with a passage 119 formed axially through fitting 118 and through which fuel can be ejected from the cylindrical passage 18 into the main fuel passage 58 under pressure from the pump piston 100. Passage 119 is formed off axis relative to passage 58 so that the ejected fuel will not strike rod 66 and be directed into the well 20. This is shown in FIGURE 4.

A low speed or idle circuit is provided in the carburetor and consists of an idle tube 111 (FIGURE 4) pressfitted into the upper portion of the bore 101. The lower end of tube 111 is opened to receive fuel from Well 103. The upper end of the tube is connected to a cross passage 113 (FIGURE 5) which in turn is connected to a downwardly extending passage adjacent to the mixture conduit 12 of the carburetor. The passage 115 in turn extends into a chamber adjacent to the closed position of throttle 22. An idle port 142 extends from chamber 140 to the mixture conduit 12 and to both sides of throttle 22 in its fully closed position. A further passage 121 extends downwardly from the chamber 140 to a second idle port 123 in the flange 13 of the casting 10. The idle port 123 opens into the intake manifold M of the carburetor when the carburetor is mounted on the engine. The passage 121 forms an idle metering jet. The flow of fuel and air therethrough is controlled by an adjustable idle screw 125 threaded into an embossment 127 formed in the casting 10. A fixed metering restriction 129 is fittetd into the down passage 115 to control the fiow of idle fuel through the passage. A further restriction 131 is press-fitted into the upper end of passage 115, which also opens into the mixing conduit 12 to provide a controlled supply of air into passage 115.

As also shown in FIGURE 6, the annular channel 117 between fitting 118 and the upper end of passage 58, is connected by a further passage 141 to the air space 143 in the fuel bowl 36 above the level of the fuel in bowl 36. Air space 143 is formed in the upper end of the fuel bowl cover section 14 of casting 10. This space is connected to the air horn through a passage 145 (FIG- URE 5) formed in the fuel bowl cover section 14 and into which a tubular fitting 147 is fixed extending into the air horn section of the carburetor. Passage 145 and fitting 147 from an internal vent for the fuel bowl and exposes the surface of the fuel in the bowl 36 to the atmospheric pressure of air entering through the air filter` 29 of the carburetor.

Within the passage 141, extending between the annular passage 117 and the portion 143 of the fuel bowl cover, there is positioned a small restriction 148 to control the iiow of air from the fuel bowl into the annular passage 117. Passage 141 thus permits air to be bled into the

passages

119 and 18 of the accelerating circuit during normal operation of the carburetor when there is a low pressure present in the passage 58. Without such an air bleed to provide a vacuum break, fuel would be gradually forced out of the accelerating pump cylinder 16 and through the

fuel passages

18 and 119 into the main fuel passage 58 during high speed operation of the engine. Then, when accelerating is needed, the lack of fuel in the cylinder 16 will cause a stumbling effect -of the engine.

The operation of the structures described are as follows: Fuel from the fuel bowl 36 flows into both the pump cylinder 16 and the

well structures

20 and 103 through

openings

108, 69 and 107, respectively, to fill these recesses to the level of the fuel in the bowl. When the engine is running, air is sucked through the air filter 29 into the mixture conduit 12 and the intake manifold M. The flow of air through the booster venturi 32 provides a sub-atmospheric pressure within the venturi surface 34 which extends back through the fuel passage 58 to the upper end of fuel well 20. The atmospheric pressure on the surface of the fuel within bowl 36 raises the fuel within the well and simultaneously air is sucked through the restriction 98 and the bleed passage 96 into the upper portion of the fuel well 20. This air passes around and through the apertures 63 in the emulsion tube 62 to mix with the fuel and its vapor and to form an air-fuel emulsion. The emulsion is carried upwardly from the fuel well into the main fuel passage 58 and out the nozzle 60 to form a fuel and air mixture with the air passing through the mixture conduit 12. During engine operation fuel flows into the bottom of well 20 through the fixed jet 105 and passage 109 and the variable jet 56. Also, when the manifold pressure downstream of the throttle 22 is less than the air pressure upstream of the throttle, additional fuel will be forced from well 103 through the idle tube 111 and passages 113 and 115 and out the idle port 142. Air will bleed through restrictions 131 and 144 into passage 115 to form an emulsion with the fuel .and to accelerate it through the

ports

142 and 123.

At low engine speeds, the throttle 22 is partially closed so that the manifold vacuum in the intake manifold M below the throttle 22 is relatively high. This vacuum is effective through the passage 94 upon the upper surface of diaphragm 80 so that atmospheric pressure against the under surface of diaphragm 80 will press the diaphragm upwardly and permit the metering rod and its retainer 70 to be carried with it in an upward direction. This brings the thicker portion of the metering rod end 68 into the main jet orifice 69 to cut down the flow of fuel through this orifice in accordance with the lower engine speed. As the throttle 22 is opened progressively from low speed to high speed, the vacuum pressure in the manifold drops and permits spring 90 to bias the diaphragm 80 and the metering rod 66 downwardly until a thinner portion of the rod end 68 enters the jet orice to provide a greater iiow of fuel into the mixing conduit 12.

The operation of the low speed idle circuit occurs when the throttle 22 is operated in or near its closed position shown in FIGURE 5. At this closed throttle position, the manifold pressure below downstream of throttle 22 is very low, Iso that fuel is forced from the fuel well 103 upwardly through idle tube 111, through passages 113, 115 and through the idle jet 121. Simultaneously air is sucked through the restriction 131 to mix with the idle fuel and form an air fuel emulsion at this point. Additional air enters the idle chamber 140 through the restricted passage 144 between mixture conduit 12 and passage 115 and through that portion of the idle port 142 which extends above the closed position of throttle 22. The amount of idle fuel and air mixture passing through the idle jet 121 and out the idle port 123 may be adjustably controlled by the idle screw 125 having a tapered lower end which is moved in and out of the idle jet 121 to vary the ow of fuel and air through jet 121.

Additional air and fuel mixture is sucked from the chamber through the portion of idle port 142 below the throttle. As the throttle is slowly opened, more and more of the idle port 142 is uncovered and exposed to the manifold vacuum to provide a greater amount of air and fuel into the intake manifold to increase the speed of the engine. This also provides a smooth transition from low speed operation of the engine to the operation of the engine at which the main fuel circuit takes over. During low speeds of engine operation, insufficient air flow passes through the venturi 32 of the mixture conduit 12 to draw fuel through the main nozzle 60. With the increase of fuel ow through idle port 142, engine speed increases t0 a point where air ow through venturi 32 begins to draw fuel through the main nozzle 60.

The accelerating pump rod 102 is connected with a lost motion connection 124 (FIGURES 1 and t2) by a linkage 126 to the throttle lever 128 which is fixed for simultaneous movement with the throttle shaft 24. Throttle lever 128 has an arm 129 adapted to be connected to any means for manual operation of the throttle 22. Any opening of the throttle by lever 12S will allow spring 104 through the lost motion connection 124 to press accelerating pump piston 100 downwardly and force fuel out of the lower portion of the pump cylinder 16 through passage 112 upwardly past the gravity biased valve 116 and into the annular portion 117 of the fitting 118. This accelerating fuel under pressure will spurt out of the passage 119 and will be directed into the nozzle structure 60 to provide additional fuel for the increased air How due to the opening of the throttle 22. This provides rapid response of the engine upon opening of the throttle.

The choke valve 26 is controlled during cold weather and during cold starts by a thermostatic choke control device enclosed in a housing structure 130. The choke control consists of a thermostatic coiled bimetallic spring 132 having one end fixed t0 a stationary stud 134 mounted on the housing 130. The other end of the thermostatic spring rests against one arm 136 of a lever fixed to the choke shaft 2S. When the engine is cold, the thermostatic spring is tensioned in one direction t0 press against the end of the lever 136 and rotate the choke Valve 26 toward a closed position. The iiow of air through the mixing conduit 12 at this point will partially open the unbalanced choke valve 26 to permit sufficient air to pass on into the intake manifold M. As the engine heats up, the spring 132 relaxes and releases the end of lever 136 so that after a predetermined temperature has been reached the thermostatic coil 132 has no effect on the choke 26, which now will remain open by gravity, due to its unbalanced construction. The details of the choke are shown and described in the copending application of Jesse L. Szwargulski, Serial No. 140,371, filed September 25, 1961, now Patent No. 3,133,977.

The carburetor structure described is one which provides the fabrication of a carburetor with cost reduction features. All portions of the carburetor, except the fuel bowl, are formed from a single casting into which the passages and chambers are easily formed by well known machining and drilling. Several fuel circuits are cornpactly assembled in a depending portion of the carburetor which extends into the fuel bowl and is completely surrounded by fuel in the bowl during operation. This provides a cooling and insulating effect of these critical portions of the carburetor by the fuel in the fuel bowl so that a minimum amount of ambient heat is absorbed by these carburetor parts. This minimizes a vaporization of the fuel in the fuel passages and reduces the chances of vapor lock during carburetor operation.

The metering rod 66, as described, is operated by the vacuum motor attached directly to the metering rod and which is directly aligned with the metering rod. This'. eliminates connecting linkages and levers which would otherwise be necessary. Also, the metering rod 66 is. operatively disposed within the emulsion tube 62 and forms a compact arrangement of these structures with thel emulsion tube passage directly intersecting the main nozzle passage. Also, by feeding Athe accelerating fuel circuit directly into the main nozzle passage 58, a separate nozzleI structure and connecting passages are eliminated. The: accelerating pump cylinder 16, as well as the passage 18,. and the well structures and 103 are all closed at their bottom ends by press-fittings. However, as in the caseof the fitting 56, shown in FIGURE 4, these fittings may' be threaded into the ends of these passageways. Im either ease, however, the fittings are easily accessible upon: removal of the fuel bowl and can be easily replaced or serviced if desirable.

The arrangement of the

interconnected fuel wells

20 and 103, as shown in FIGURE 4, provides an advantage in that fuel passing through the restriction 107 is constantly flowing over the lower end of the idle tube 111. This is true whether the fuel is passing through the passage 109 into the main fuel well 20 and up the emulsion tube 62,' or whether the fuel'is passing upward through the idle tube 111 during low speed operation of the engine. This constant fiow of fuel past the end of idle tube 111 prevents the possible collection of fuel vapors around the end of the tube and the passage of such vapors up the idle tube 111 into the idle fuel passages. This tends to eliminate any tendency toward a vapor lock condition in the idle fuel passages.

We claim:

1. A carburetor for an internal combustion engine, said carburetor comprising a fuel bowl and a body formed with an air and fuel mixture conduit and adapted to be connected to the intake manifold of said engine, said body formed with a fuel passage extending between said fuel bowl and said mixture conduit, a throttle mounted within said body mixture conduit for movement from opened to closed poistion, said fuel passage formed with first and second fuel wells within said body, a fitting having a restricted orifice therethrough fixed to said body at the lower end of said first fuel well and positioned within said fuel bowl, a metering rod movably mounted within said first fuel well, said metering rod having one end thereof positioned for movement through said restricted orifice, an emulsion tube depending from said body within said first fuel well and having a lower free end thereof spaced from the walls of said first fuel well and from the bottom of said first fuel well, said emulsion tube surrounding said metering rod, means supported by said body for moving said metering rod end within said orifice in response to engine operation, said body formed with a fixed jet passage between said fuel bowl and said second fuel well, an idle tube fixed to said body within said second well -and having a restricted end positioned below the level of said emulsion tube and within the path of fuel ffow from ,said fixed jet to said conduit, a conduit in said body between said first and second fuel wells and positioned below the level of the free end of said emulsion tube for fuel flow Abetween the first and second fuel wells whereby fuel sive formation of Vvapor within said second fuel well.

2. A carburetor for an internal combustion engine, said carburetor comprising a fuel bowl and a body formed with an air and fuel mixture conduit and adapted to be 7 connected to the intake lmanifold of said engine, said body formed with a fuel passage extending between said lfuel bowl and said mixture conduit, a throttle mounted Within said body mixture conduit for movement from opened to closed position, said fuel passage formed with first and second fuel wells Within said body, a fitting having a restricted orifice therethrough fixed to said body at the lower end of said first fuel well and positioned within .said fuel bowl, a metering rod movably mounted within ,said first fuel well, said metering rod having one end thereof positioned'for movement through said restricted orifice, an emulsion tube depending from said body within said first fuel Well and having a lower free end thereof spaced from the walls and from the bottom of said first fuel well and surrounding said metering rod, said body formed with a fixed jet passage between said fuel bowl vand said second fuel well, a conduit formed in said body 'between said first and second fuel wells and being positioned below the level of the free end of said emulsion tube, an idle tube fixed to said body within said second well and having a restricted end positioned below the level of the free end of said emulsion tube and in alignment with said fixed jet and with said conduit, whereby fuel flowing through said fixed jet to said conduit will sweep the restricted end of the emulsion tube to cool the same and to prevent the formation of excessive fuel vapor.

3. A carburetor for an internal combustion engine, said carburetor comprising a fuel bowl and a body formed with an air and fuel mixture conduit and adapted to be connected to the intake manifold of said engine, said body lformed with a fuel passage extending between said fuel bowl and said mixture conduit, a throttle mounted within :said body mixture conduit for movement from opened to closed position, said fuel passage formed with first and second fuel wells within said body, a fitting having a restricted orifice therethrough fixed to said body at the lower end of said first fuel well and positioned within said fuel bowl, a metering rod movably mounted within said first fuel well, said metering rod having one end thereof positioned for movement through said restricted prifice, an emulsion tube depending from said body with- 1n said first well and having a lower free end thereof spaced from the walls and from the bottom of said first fuel well, said emulsion tube surrounding said metering rod, said body formed with a fixed jet passage between said fuel bowl and said second fuel well, an idle tube fixed to said body within said second well and having a restricted end positioned below the level of the free end of said emulsion tube and within the path of fuel flow from said fixed jet to said conduit, a conduit formed in said body between said first and second fuel wells and being positioned adjacent the level of the free end of said emulsion tube and aligned horizontally with the restricted end of said idle tube, whereby fuel flowing through said fixed jet passage, and through said conduit to the first fuel well will sweep the restricted end of said idle tube to keep the same cool and to prevent the formation of vapor in said second fuel well.

References Cited by the Examiner UNITED STATES PATENTS 2,660,417 ll/53 Anderson 261-34 2,771,282 ll/56 Olson et al. 261-41 2,877,996 3/59 Kinney et al 261-34 2,882,028 4/59 Seldon 261-72 2,914,307 11/ 59 Eickmann 261-69 X 3,031,172 4/62 Rapplean 261-72 X 3,076,639 2/63 Szwargulski et al 261-34 3,136,827 6/ 64 Szwargulski 261-72 X 0 HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner.

Claims

1. A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE, SAID CARBURETOR COMPRISING A FUEL BOWL AND A BODY FORMED WITH AN AIR AND FUEL MIXTURE CONDUIT AND ADAPTED TO BE CONNECTED TO THE INTAKE MANIFOLD OF SAID ENGINE, SAID BODY FORMED WITH A FUEL PASSAGE EXTENDING BETWEEN SAID FUEL BOWL AND SAID MIXTURE CONDUIT, A THROTTLE MOUNTED WITHIN SAID BODY MIXTURE CONDUIT FOR MOVEMENT FROM OPENED TO CLOSED POSITION, SAID FUEL PASSAGE FORMED WITH FIRST AND SECOND FUEL WELLS WITHIN SAID BODY, A FITTING HAVING A RESTRICTED ORIFICE THERETHROUGH FIXED TO SAID BODY AT THE LOWER END OF SAID FIRST FUEL WELL AND POSITIONED WITHIN SAID FUEL BOWL, A METERING ROD MOVABLY MOUNTED WITHIN SAID FIRST FUEL WELL, SAID METERING ROD HAVING ONE END THEREOF POSITIONED FOR MOVEMENT THROUGH SAID RESTRICTED ORIFICE, AN EMULSION TUBE DEPENDING FROM SAID BODY WITHIN SAID FIRST FUEL WELL AND HAVING A LOWER FREE END THEREOF SPACED FROM THE WALLS OF SAID FIRST FUEL WELL AND FROM THE BOTTOM OF SAID FIRST FUEL WELL, SAID EMULSION TUBE SURROUNDING SID METERING ROD, MEANS SUPPORTED BY SAID BODY FOR MOVING SAID METERING ROD END WITHIN SAID ORIFICE IN RESPONSE TO