US2615695A - Carburetor - Google Patents

Description

Patented Oct. 28, 1952 CARBURETOR AlbertH. Wink-ler, Elmira, N. Y., assignor to'Bendix Aviation Corporation, South Bend, Ind., a

corporation of Delaware Application January 3, 1949, Serial No. 68,783

6 Claims. 1

The present invention relates to a carburetor for an internal combustion engine and more particularly to an improved accelerating pump discharge system for said carburetor.

It is one of the principal objects of the present invention to provide an accelerating pump discharge system for a carburetor, wherein the fuel cannot be withdrawn by suction in the induction passage except when the pump is in operation.

Another object of the invention is to provide a fuel system for an accelerating pump wherein percolation of the fuel will not produce a discharge of fuel from the system.

' A further object of the invention is to provide a relatively simple, eflicient, and easily serviced accelerating pump discharge system for a carburetor from which no discharge of fuel occurs during normal engine operation except during the operation of the pump.

Additional objects and advantages of the present invention will be apparent from the following description and accompanying drawings, where- Figure 1 is a vertical cross-section of a carburetor in which some of the elements have been rearranged to more clearly show their operative relationship to one another; and

Figure 2 is a modified and enlarged fragmentary cross-sectional view of the accelerating pump discharge system and venturi shown in Figure 1.

Referring more specifically to the drawings, wherein two embodiments of my invention are shown, numeral designates .an induction passage of the carburetor, l2 the air inlet, [4 the mixture outlet, IS a choke valve, and [8 a throttle valve, said throttle valve being mounted on a throttle valve shaft journaled in the throttle body of the carburetor. A conventional fuel bowl 22 is formed integrally with the main body of the carburetor and is provided with a fuel inlet valve 24 and a float mechanism 26 for controlling the flow of fuel through inlet valve 24. The fuel is discharged into the induction passage at the throat of the venturi 30 through a main discharge nozzle 32 which communicates with the fuel bowl through a Well 34 and a main fuel metering jet 36 located along one side of Well 34. A sleeve 40, having several small holes 42 in the wall thereof, is disposed in said well and is spaced from the internal wall thereof to permit air and fuel to surround the sleeve and pass through holes 42 into the internal portion of said sleeve. The air entering well 34 and sleeve 40 is admitted from the air intake end l2 of the induction passage through a port and ismetered at orifice '46 as it passes downwardly through passage 48 to the annular space between sleeve and the side wall of well 34. In this construction, the fuel flows from bowl 22 through metering orifice 36 into well 34 and the lower end of sleeve 40 and passes upwardly through said sleeve where it forms an emulsion with the air admitted through the holes 42. The fuel-air emulsion so formed is discharged through nozzle 32 into the throat of the venturi 30.

The fuel nozzle 32, which is claimed in my copending application Serial No. 8,951, filed February 1'7, 1948, is arranged to discharge fuel adjacent the under side of a horizontal bar 5|] and is provided near the discharge end thereof with a downwardly tapering ear -52 to prevent fuel from flowing along the under side of said nozzle to the venturi and thence down the side wallof the induction passage. A similar ear 54 is disposed on the opposite side of the venturi under bar 50.

A manually actuated accelerating pump, generally shown at consists of a cylinder 62, a piston 64 and a linkage 65 connecting the upper end of said piston with the throttle valve and including a lever 66, a link 68 and a lever 10 mounted on one end of shaft 20, as shown in ,Figure 1, said lever 66 imparting movement to said piston through a spring 12 which provides a sustained flow of fuel when the throttle valve is opened. When piston 64 is raised, fuel flows from the fuel bowl through a check valve controlled conduit 13 into the lower portion of cylinder 62, and as the piston is moved downwardly on the opening movement of the throttle valve, the fuel is discharged from the lower end of cylinder 62 through conduit 14, cylindrical chamber 15, conduit 16 and discharge orifice ll disposed near the throat of venturi 30. An air duct 18 connects the upper end of chamber 15 with the induction passage 10 above venturi 30 to break the effect of venturi suction transmitted through conduit'lii to chamber 15.

A ball check valve disposed in chamber 15 is adapted to seat over the fuel inlet of the chamber when the accelerating pump is not in operation and to seat over the air inlet, i. e. the lower end of duct 18, when the fuel is being discharged from the accelerating pump. The ball check valve and air duct thus permit air to bleed through chamber 15 and conduit 16 when the pump isnot in operation and thereby prevent the suction in the throat of the venturi from siphoning fuel from the accelerating pump cylinder. In order to assure positive seating of ball 80 over the air duct 18 during the time the accelerating pump is discharging, a ball is used having only slightly smaller diameter than that of chamber I5, and the conduit I is connected to chamber 15 at a point above the horizontal axis of said ball when the ball is in the position for closing air duct I8. Thus the fuel must pass through the smallest clearance between the ball and the side wall of the chamber to reach the entrance to conduit 16 and, in so doing, constantly urges the ball to its seated position over the lower end of duct I8 throughout the time the fuel is being discharged by the pump. For best operation of the ball check valve 80, the fuel inlet in the bottom of chamber I5, over which said ball valve seats when the accelerating pump is inoperative, should be located above the normal fuel level in the fuel bowl.

During the operation of the engine, the temperature of the carburetor and the fuel therein sometimes becomes sufficiently high to cause percolation of the fuel in the accelerating discharge conduit I4, the vapor bubbles so formed risingin said conduit, lifting ball valve 80 and then bursting in chamber I5. In order to prevent the fuel carried into said chamber during percolation from flowing through passage I6 into the induction passage I0 and producing an unduly rich fuel-air mixture for the engine, chamber 15 must have sufficient height to permit the vapor bubbles to rise and break without submerging the entrance of conduit I6 in fuel or cutting off the air supply by seating ball 80 over the lower end of air duct I8. As shown in the drawing, the entrance to conduit I6 is located at substantially the highest place in the chamber.

The idle system of the carburetor includes an anti-percolating well 88, a horizontal passage 90 connecting said well with the lower portion of well 34, and a discharge conduit 92 connecting well 88 with the induction passage at ports 94 and 96 above and below the throttle valve I8, respectively. This system is described in detail and claimed in my copending application mentioned hereinbefore and therefore will not be described here.

A power enrichment jet I00 connects the fuel bowl with conduit 90 and is controlled by a valve I02 urged to its closed position by a spring I04. Valve I02 is operated. by a reciprocable rod I06 which is urged in the direction to open said valve by a spring I08 reacting between a Plate IIO secured to the lower end of said rod and a disc-like plate I I2 secured to the fuel bowl cover. The rod I06 is secured to and actuated by a piston II4 mounted in cylinder II6 which is connected at its upper end by a conduit, not shown, with the induction passage on the engine side of the throttle valve. Duringhigh power output when manifold vacuum is low, spring I08 urges plate IIO against the stem of valve I02 and opens the valve to permit additional fuel to flow through conduit 90 into well 34 to supply an enriched fuel-air mixture to the engine.

It is contemplated that other arrangements of elements than those shown in the accompanying drawings may be provided without departing from the scope of the present invention. For example, the air duct I8 may be connected with the space above the fuel in the fuel bowl, or directly with the atmosphere, so that the suction in the induction passage when the choke valve is in closed or partially closed position will not cause fuel to discharge from the accelerating pump system. This modification is shown in Figure 2 wherein air duct 18 is connected with 4 the space above the fuel in the fuel bowl adjacent the accelerating pump. Further, other elements may be incorporated in the carburetor and additional modifications of the main fuel and idle systems and accelerating pump may be made to satisfy requirements.

I claim:

1. In an accelerating pump discharge system for a carburetor: a chamber, a fuel inlet port in the bottom of said chamber, an air inlet port in the top of said chamber, a ball in said chamber adapted to seat over the fuel inlet port when said pump is inoperative and to seat over the air inlet port when the pump is operative, and a fuel outlet for said chamber disposed at a point therein above the horizontal axis of said ball when the ball is seated over the air inlet port.

2. In an accelerating pump discharge system for a carburetor: a cylindrical chamber in substantially vertical position, a fuel inlet port in the bottom of said chamber, an air inlet port in the top of said chamber, a ball in said chamber adapted to seat over the fuel inlet port when the pump is inoperative and to seat over the air inlet port when the pump is operative, and a fuel outlet for said chamber disposed at a point in said chamber above the horizontal axis of said ball when the ball is seated over the air inlet.

3. In a carburetor for an engine: an accelerating pump discharge system comprising an elongated cylindrical chamber in substantially vertical position, a fuel inlet port centrally located in the bottom of said chamber, an air inlet port centrally located in the top of said chamber, a ball in said chamber of only slightly smaller diameter than said cylindrical chamber adapted to seat over the fuel inlet port when said pump is inoperative and to seat over the air inlet port when the pump is operative, and a fuel outlet for said chamber disposed at a point in the chamber above the horizontal axis of said ball when the ball is seated over the air inlet port.

4. In a carburetor having an induction passage: an accelerating pump, a chamber, a fuel conduit connecting said accelerating pump with the bottom of said chamber, an air inlet conduit connecting the top of said chamber with the induction passage, a ball in said chamber adapted to close the first mentioned conduit when said pump is inoperative and to close the second mentioned conduit when the pump is operative, and a conduit connecting the induction passage with said chamber at a point above the horizontal axis of said ball when the ball is in the position for closing the second mentioned conduit.

5. In a carburetor having an induction passage with a venturi therein: an accelerating pump, a cylindrical chamber in substantially vertical position, a fuel conduit connecting said accelerating pump with the bottom of said chamber, an air inlet conduit connecting the top of said chamber with the induction passage anterior to said venturi, a ball in said chamber of only slightly smaller diameter than said chamber adapted to close the first mentioned conduit when said pump is inoperative and to close the second mentioned conduit when the pump is operative, and a conduit connecting the throat of the venturi with said chamber at a point above the horizontal axis of said ball when the ball is in the position for closing the second mentioned conduit.

6. In a carburetor having an induction passage: an accelerating pump, a chamber, a. fuel conduit connecting said acceleratin pump with the bottom of said chamber, an air inlet conduit 2,615,695 5 I 6 connecting the top of said chamber with the fuel a REFERENCES CITED bowl above the fuel level therein, a ball in said chamber adapted to close the first mentioned conduit when said pnmp'is inoperative and to The following references are of record in the file of this patent:

close the second mentioned conduit when the 5 UNITED STATES PATENTS pump is operative, and a conduit connecting the Number 1 Name Date induction passage with said-chamber at a point 2,182,393 Ball et a1. Dec. 5, 1939 above the horizontal axis of said ball when the 2,194,540 Breeze Mar. 26, 1940 ball is in the position for closing the second men- 2,199,509 Olson May 7, 1940 tioned. conduit. 10 2,274,467 Ball Feb. 24. 1942 ALBERT H. WINKLER.

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