US3754739A

US3754739A - Carburetor air/fuel distribution control

Info

Publication number: US3754739A
Application number: US00165423A
Authority: US
Inventors: G Buike; W Haboush
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1971-07-21
Filing date: 1971-07-21
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28
Also published as: DE2228167B2; JPS5025976B1; AU459913B2; DE2228167A1; CA982433A; AU4415172A; DE2228167C3; GB1387295A

Abstract

The air valve of a dual stage carburetor has a tapered fuel metering rod secured to it and movable as a function of air valve movement to increase fuel flow; the fuel inducted passes through a hole in the air valve and splashes against a member that deflects the fuel downwardly to provide good fuel and air distribution on both sides of the valve; the splash member and air valve together act as a venturi at higher engine speed air flows to provide a greater than normal fuel metering signal at the fuel nozzle, thereby providing greater fuel delivery volume at the higher engine speeds.

Description

United States Patent 91 Buike et a1.

[ CARBURETOR AIR/FUEL DISTRIBUTION CONTROL [75] Inventors: George W. Buike, Plymouth; William P. Haboush, 11, St. Clair Shores, both of Mich.

[73} Assignee: Ford Motor Company, Dearborn,

Mich.

[221 Filed: July 21, 1971 211 Appl. No.: 165,423

[52] US. Cl 261/50 A [51] Int. Cl. F02m 19/04 [58] Field of Search 261/50 A, 50 R [56] References Cited UNITED STATES PATENTS 1,900,191 3/l933 Mock 261/50 A 3,322,408 5/1967' Stoltman 261/50 A Harrison 261/50 A Sweeney 261/50 A Primary ExaminerTim R. Miles Attorney-Keith L. Zerschling et a1.

[ ABSTRACT The air valve of a dual stage carburetor has a tapered fuel metering rod secured to it and movable as a function of air valve movement to increase fuel flow; the fuel inducted passes through a hole in the air valve and splashes against a member that deflects the fuel downwardly to provide good fuel and air distribution on both sides of the valve; the splash member and air valve together act as a venturi at higher engine speed air flows to provide a greater than normal fuel metering signal at the fuel nozzle, thereby providing greater fuel delivery volume at the higher engine speeds.

10 Claims, 3 Drawing Figures Patented Aug. 28, 1973 I 3,754,739

INVENTORS ATTORNEYS CARBURETOR AIR/FUEL DISTRIBUTION CONTROL This invention relates, in general, to a multi-barrel, downdraft type carburetor. More particularly, it relates to a carburetor having primary and secondary stages of operation, the secondary stage having a fuel metering system operably connected to an air valve.

It is a primary object of the invention to improve the air and fuel flow distribution through the secondary throttle bore of a carburetor having a fuel metering system of the type that varies the fuel jet area as a function of the movement of the air valve. The invention provides a fuel flow deflection plate to'not only guide the secondary fuel flow into the throttle bore in a manner to provide good distribution to all the engine cylinders, but the deflecting plate also at times acts as a venturi to increase the air flow velocity at higher air flows to allow a greater than conventional fuel delivery at higher engine speeds.

The prior art devices that are directed to multi-barrel carburetors having primary and secondary stages and secondary fuel metering systems operable by air valves generally have only fixed attitude fuel jet nozzles so that the fuel is discharged in one direction only, with no increase above the normal increase in fuel flow delivery volume as a function of the increase in air flow.

It is an object of the invention, therefore, to provide a carburetor fuel and air flow deflecting member that not only guides the fuel into the carburetor bore in an efficient manner, but also serves as a venturi at high air flows to increase the air flow velocity past the fuel jet in a manner providing a greater delivery of fuel.

Other objects, features and advantages of the invention will become more apparent upon reference to the succeeding detailed description thereof, and to the drawings illustrating a preferred embodiment thereof; wherein, a

FIG. 1 is a top plan view of a multi-barrel carburetor embodying the invention; 1

FIG. 2 is a cross-sectional view of a portion of the air horn section of the carburetor of FIG. 1 taken on a plane indicated by and viewed in the direction of the arrows 2-2 of FIG. 1; and, I

FIG. 3 is a perspective side view of the carburetor of FIG. 1, with parts broken away and in section, illustrating the invention in a different operative position than that shown in FIG. 2.

FIGS. 1 and 2 show the outline and a portion of the air horn section, respectively, of a conventional, except for the invention, four barrel carburetor of the downdraft type. It contains two primary throttle bores 12 that are closed at times by a conventional choke plate 14. The latter is fixed for rotation with a shaft 16 rotatably mounted in the carburetor body walls. The carburetor also contains a pair of secondary bores 18, flow through both being controlled by an air valve 20. The latter is fixed for rotation with a shaft 22 also rotatably mounted in the walls of the carburetor body. The carburetor body portion 24 dividing the primary and secondary bores is cast at its lower end to provide an angled secondary fuel passage 24 that leads from a conventional fuel bowl, not shown.

The remaining details of construction and operation of the carburetor per se are not given since they are known and believed to be unnecessary for an understanding of the invention. Suffice it to say that the carhole 30 to the far side of air valve 20 to provide better buretor would have the usual main fuel metering system leading from the fuel bowl to the primary bores 12 for supplying fuel to the engine during low speed and low air flow operation thereof. The fuel supply to the secondary throttle bores 18 for operation during higher engine speeds and air flows is supplied through the fuel passage 24, in a manner now to be described.

The air valve 20 in general is of conventional construction. It is a plate fixed to shaft 22 in an unbalanced manner so as to be responsive to the forces of air acting thereon when the throttle valves, not shown, located below in the carburetor, are opened to admit secondary air and fuel into the engine proper.

The underside of air valve plate 20 is provided with an ear or socket 26 to which is hingedly mounted the end of a tapered fuel metering rod 28. The metering rod in turn slidably projects through the upper opening of the fuel passage 24 so as together with the fuel passage define a fuel jet or nozzle 29 that varies in area as a function of the movement of the air valve.

That is, as the air valve rotates in a clockwise direction to increase the flow of air into the engine, the tapered metering rod 28 will be moved inwardly into the fuel passage 24 to increase the annular area of the fuel jet nozzle between the walls of the rod and passage, thereby permitting an increasingly greater volume of fuel to be inducted into the secondary bores or passages 18 as the air valve opens.

As thus far described, the construction is conventional. With the fuel jet nozzle 29 directed diagonally upwardly at an attitude as shown in FIG. 2, however, it will be evident that fuel being inducted from passage 24 will spew outwardly into bore 18 and splash against the underside of plate 20. It will be equally clear that no fuel will be permitted to pass to the upstream or far side of air valve vplate 20 so that as the air valve reaches an essentially vertical position, fuel will flow down through essentially only half of the throttle bore area. This results in poor distribution of fuel and air to the intake manifold of the engine and to the individual engine cylinders, resulting in inefficient engine operation.

To obviate the above disadvantage, the air valve plate 20 is provided with a hole, aperture or opening 30 over each throttle bore aligned essentially with the discharge outletof fuel nozzle 29. Fuel now discharged from the nozzle passes in a fan shape spray through distribution of the fuel flow into the main induction passage 18.

However, to prevent undue fogging of the fuel spray on the far side of plate 20, which again would result in unequal distribution of fuel and air to the engine cylinders, it is necessary that the fuel not be permitted a free distribution, but that it be directed downwardly to a more advantageous attitude to assure an essentially equal distribution throughout the bore of fuel on both sides of the valve plate 22.

Accordingly, an essentially dome or hat-shaped fuel deflecting member 32 is attached to the air valve plate 20 over each of the holes or apertures 30 to deflect the fuel downwardly into the throttle bores in the most advantageous direction providing the best distribution of fuel and air flow into the intake manifold. The deflecting member in this case consists essentially of an inverted open end channel-shaped member.

In addition to serving as a fuel deflecting member, each member 32 also acts as a venturi at higher air flows at higher engine speeds to increase the fuel metering signal acting on the fuel nozzle 29 to thereby increase the fuel delivery volume at this time. The latter effect is more clearly shown in FIG. 3 where it can be seen that when air valve plate 20 is rotated nearly to its vertical position indicating essentially wide open throttle operation, the deflector plates are then essentially aligned with the air flow direction so that a maximum venturi effect is accomplished, as indicated by the arrows. The increased air velocity through the venturi creates an even greater depression at the fuel jet nozzle 29 to effect a greater than normal delivery of fuel at this time.

The operation is believed to be clear from the above description, and, therefore, is not repeated. From the foregoing, it will be seen that the invention improves the fuel and air distribution through the secondary bores of a multi-barrel air valve type carburetor by guiding the fuel in an efficient manner, and increasing fuel delivery volume at high engine speeds.

We claim:

I. A carburetor air/fuel mixture flow control device for use in a carburetor having an air/fuel induction passage, with an air inlet at one end and connected to an engine intake manifold at the other end, the passage having a valve rotatably mounted thereacross for movement between positions opening and closing the passage, a fuel passage outlet opening into the passage adjacent and below the valve, fuel metering means secured to the valve and projecting into the fuel outlet in a manner to vary the quantity of fuel flow inducted into the passage as a function of the rotative position of the valve, and fuel and air flow directing means secured to the valve for rotative movement with it for directing the flow of fuel and air into the passage in a manner to maximize air/fuel mixture distribution through the passage, the valve having an aperture therein for passage therethrough of fuel inducted into the passage, the directing means comprising deflecting means in the path of the fuel inducted to be engaged by the fuel and deflect the fuel downwardly into the passage.

2. A control device as in claim 1, the deflecting means comprising an open end dome shaped hollow channel-like member overlying the aperture in the valve, the deflecting means also constituting a venturi at higher air flows when the valve is rotated towards an open position for increasing the flow velocity of the air therethrough to thereby induct a greater fuel flow at higher air flows at higher engine speeds.

3. A control device as in claim 1, the deflecting means preventing splashing of fuel against the walls of the induction passage by causing fuel to be splashed against the deflecting means and redirected downwardly at an attitude providing uniform distribution throughout the passage.

4. A carburetor air/fuel mixture flow control device for use in a carburetor having an air/fuel induction passage, with an air inlet at one end and connected to an engine intake manifold at the other end, the passage having a valve rotatably mounted thereacross for movement between positions opening and closing the passage, a fuel passage outlet opening into the passage adjacent and below the valve, fuel metering means secured to the valve and projecting into the fuel outlet in amanner to vary the quantity of fuel flow inducted into the passage as a function of the rotative position of the valve, and fuel delivery volume increasing means mounted on the valve for movement therewith for increasing fuel flow at higher air flows upon rotation of the valve to an increased air flow position, said fuel delivery volume increasing means including a hole in the valve aligned with the fuel outlet for induction of fuel through the hole into the passage, and venturi means secured to the valve over the hole whereby air passing through the venturi at increased air flows upon opening rotative movement of the valve increases the fuel delivery volume.

5. A control device as in claim 4, the venturi being defined by an open end inverted channel shaped member overlying the hole and directing fuel splashed thereagainst downwardly towards the center of the passage.

6. A control device as in claim 5, the splash surface of the member being essentially at right angles to the diredtion of fuel flow from the fuel outlet.

7. A control member as in claim 4, the venturi means being secured to the upstream side of the valve.

8. A carburetor fuel and air flow control member comprising, an air valve rotatable mounted across a carburetor induction passage, the latter having a fuel outlet port downstream of the valve, the valve having a tapered fuel metering rod movable with the valve variably in'to'the fuel outlet to constitute a variable area fuel jet, the valve having an opening aligned with the flow of fuel from the jet into the passage so as to permit the passage of the fuel therethrough, and a fuel flow directing means and fuel volume control member secured to the valve on the upstream side of the valve over the opening for deflecting the fuel flow downstream towards the center of the induction passage to minimize fuel fogging while providing good distribution of fuel and air throughout the passage.

9. A control member as in claim 8, the control member consisting of an inverted channel shaped member covering the opening and constituting a splash surface for the fuel.

10. A control member as in claim 8, the control member consisting of a dome like member open at its ends and covering the opening to define a venturi operable at higher air flows to increase the velocity of air passing through the venturi to increase the fuel metering induction signal on the fuel jet to increase fuel flow at this time.

Claims

1. A carburetor air/fuel mixture flow control device for use in a carburetor having an air/fuel induction passage, with an air inlet at one end and connected to an engine intake manifold at the other end, the passage having a valve rotatably mounted thereacross for movement between positions opening and closing the passage, a fuel passage outlet opening into the passage adjacent and below the valve, fuel metering means secured to the valve and projecting into the fuel outlet in a manner to vary the quantity of fuel flow inducted into the passage as a function of the rotative position of the valve, and fuel and air flow directing means secured to the valve for rotative movement with it for directing the flow of fuel and air into the passage in a manner to maximize air/fuel mixture distribution through the passage, the valve having an aperture therein for passage therethrough of fuel inducted into the passage, the directing means comprising deflecting means in the path of the fuel inducted to be engaged by the fuel and deflect the fuel downwardly into the passage.

4. A carburetor air/fuel mixture flow control device for use in a carburetor having an air/fuel induction passage, with an air inlet at one end and connected to an engine intake manifold at the other end, the passage having a valve rotatably mounted thereacross for movement between positions opening and closing the passage, a fuel passage outlet opening into the passage adjacent and below the valve, fuel metering means secured to the valve and projecting into the fuel outlet in a manner to vary the quantity of fuel flow inducted into the passage as a function of the rotative position of the valve, and fuel delivery volume increasing means mounted on the valve for movement therewith for increasing fuel flow at higher air flows upon rotation of the valve to an increased air flow position, said fuel delivery volume increasing means including a hole in the valve aligned with the fuel outlet for induction of fuel through the hole into the passage, and venturi means secured to the valve over the hole whereby air passing through the venturi at increased air flows upon opening rotative movement of the valve increases the fuel delivery volume.

8. A carburetor fuel and air flow control member comprising, an air valve rotatable mounted across a carburetor induction passage, the latter having a fuel outlet port downstream of the valve, the valve having a tapered fuel metering rod movable with the valve variably into the fuel outlet to constitute a variable area fuel jet, the valve having an opening aligned with the flow of fuel from the jet into the passage so as to permit the passage of the fuel therethrough, and a fuel flow directing means and fuel volume control member secured to the valve on the upstream side of the valve over the opening for deflecting the fuel flow downstream towards the center of the induction passage to minimize fuel fogging while providing good distribution of fuel and air throughout the passage.