US1872654A - Carburetor - Google Patents

Description

Aug. 23, 1932. G. M. BICKNELL CARBURETOR Filed Oct. 22. 1927 www? Patented Aug. 23, 1932 UNITED STATES PATENT? OFFICE GEORG-E M. BIQKNELL, OF ST. LOIS, MISSOURI, ASSIGNOR TO CARTER CARBURETOR CORPORATION, X' ST. LOUIS, MISSOURI, A CORPORATION OF DELAWARE CARBUBETOB Application mea october 22, `1927. serial No. 227,979.

g details of construction shown and described,

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as it is obvious that various modications thereof within the scope of the claims will occur to persons skilled in the art.

In said drawing:

Figure 1 isa sectional view through a carburetor showing the present invent-ion;

Fig. 2 is a side elevation of the carburetor,

certain parts being broken away to show the interior of the oat chamber; and

Fig. 3 is a sectional view on the line 3-3 of Fig. 1.

This invention relates generally to carburetors and has particular reference to an economizer therefor. l

Itis well known that the average motorist wastes motive fuel during the operation of the vehicle. Usually this is because the motorist uses more fuel than is necessary or required during normal running of the vehicle; that is, when the throttle is only partly open. In other words, a fuel mixture which is too rich in gasoline at these periods is used. To offset this is one of the objects of this invention, tion comprises means whereby during the operation of the engine the fuel mixture is automatically controlled whereby to vary the relative ratio of the several components of the mixture.

As is further well known, the power required to propel a vehicle at a given speed along a level road is considerably less than the power required to drive that same vehicle up an incline at the same rate of speed. In addition it has been found that the power developed is dependent not only ,on the amount of motive fuel but upon the specific fuel mixture; that is, for example, the ratio of the several components of the mixture. Still further, as a concrete example, a vehicle capable of a speed of sixty miles per hour on a level road might have a speed'of approxi- .mately forty-five miles per hour with the and to that end the present inven-v ly fifteen miles -per hour with the throttle wide open on a sulicient incline. Obviously the fuel mixture required to drive the vehicle at half open throttle position can be leaner than the mixture required to propel the vehicle under adverse conditions such as up an incline with the throttle at full or nearly full open position. To the end that suitable fuel mixtures may be supplied to the vehicle engine in accordance with varying conditions', thepresent invention has for a further ob-l ject the provision of automatic means whereby the amount of motive fuel drawn from a lcarburetor is varied in accordance with the ly opened a comparatively lean mixture of air and gasoline is delivered to"the engine,

and when the carburetor throttle is fullyl opened a rich mixture is delivered.

A still further object of the invention is to provide a carburetor having means associated therewith whereby to vary the normal fuel mixture ejected therefrom in accordance with the throttle opening.

Other objects and advantages of this inl vention will be apparent from the following description taken with the accompanymg drawing in which a carburetor is shown hav-v ing a casing 2 of the form shown, the casingl comprising a depending hollow portion m which is formed the well 6.

The float chamber is indicated at 8 and has.`-V 'I afloat 10 therein, the float chamber being defined by the casing 11. Positioned in the well 6 is the nozzle 13, the outer end of .which projects into a standpipeor mixing conduit 12 threadedly secured as at 14 to the depending portion 4; the standpipe 12 having its upper end extended into the lower end of a Venturi tube 16 positioned in the outlet pas- 18. 2O indicates the air inlet chamber and in Fig. 1, it can be seen that the lower end of the Venturi tube extends into the air chamber 20. The base of the standpipe is provided with ports indicated at 22 to establish communication between the air chamber 20 and the carburetor well.

Slidably mounted on the standpipe or mixing conduit 12 is a choke cone 24 which is connected to a lever 26 pivoted on a shaft 28; the latter being rotatable by means of an external lever 30, shown in Fig. 2, whereby to raise or lower the lever 26 and hence the cone 24. The upper end of the lever 30'is connected by a link 31 to a lever 33, the upper end of which latter is pivoted on the rod 46. The lever 33 is adapted to be 'engaged by a set screw 50 hereinafter described carried at the lower end of a lever 48 which actuates the throttle valve in a manner hereinafter described. It will be apparent that by operating the lever 30 to elevate the choke valve 24, the throttle valve is opened through the medium ofthe links 31 and 33 and the lever 48.

It will also be vapparent that the lever 48.

may be operated independently of the choke valve operating means, but the connection of the throttle valve andchoke valve through the medium of the linkage just mentioned forms the subject matter of. a co-pendin application and really forms no part o the present case.

The upper portion of the casing is provided with a passage 32 normally'closed by a screw plug 34, the tube 36 throu h which fuel passes into the passage 32 and through an aperture 38 into the outlet passage 18 for idling purposes. The passage of fuel through aperture 38 vis controlled by means of an adjustable valve 40providedkwith a headed stem 42.

The throttle valve is indicated at 44 and is of the usual butterfly type, being mounted for rotation on a rod 46 controlled by a lever 48, the position of which may be adjusted by a screw 50. This valve is rotatable from the closed position shown by the solid line of Figure 2 tothe open position indicated bythe dotted line in the same igure.

It will be understood `that the lever 33 is loosely mounted onthe shaft 46. This lever has an abutment 75 which lies in the path of the screw 50, and'when the choke valveis closed, this abutment prevents the complete closure of the throttle valve by interfering with the movement of the screw 50. This is desirable for the purpose of insuring a slight opening of the throttle when the choke is closed for starting. The choke and throttle are otherwise operable independently.

The upper end of the standpipe 12 is provided with diametrically opposed apertures or ports 52 which in the instance shown are arranged to be covered and uncovered by a hollow cylindrical valve 54' mounted for movement within the standpipe and connected by links 56 and 58 to a bracket 60 attached to the throttle valve on one side of the center passage communicating with a.v

thereof. The bracket 60 is preferably attached to the throttle valve 44 by. rivets or screws 61, and on that side of the valve which is lowered when the valve is rotated to permit passage of fuel mixture from the standpipe through the outlet passage 18. The links 56 and 58 are pivotally connected together by means of a pin 62 or the like, as clearly shown in Fig. 3. The drawing shows the valve 54 as so connected to the throttle valve 44 that when the latter is in closed position the valve 45 covers the ports or apertures 52 and prevents the admission of air to the standpipe 12, and when the throttle valve is in full open position, the valve 54 again covers the ports 52 and prevents the admission of air therethrough into the staudpipe 12 and its mixing with the fuel mixture passing upwardly therethrough, as hereinafter described.

The drawing is for illustrative purposes only and discloses one embodiment of the invention. However, I desire it understood that the inventive thought disclosed herein is capable of variation within the spirit of the invention and I do not restrict myself to the specific arrangement of parts shown, nor do I restrict this invention to an arrangementi-such that the valve 54 will completely cover the ports 52 when the throttle valve is closed. For example, it is within the spirit and scope of this invention to so proportion the links 56 and 58 or to so connect said links with the throttle valve that when the throttle valve 44 is in fully closed position the valve 54 will not completely close the ports 52 and said valve upon opening of the throttle valve will rapidly uncover the ports 52 to permit admission of air to the standpipe, and when the throttlepvalve is fully open the valve 54 will completely cover the ports 52. Still further within the scope and spirit of the invention, the valve 54 may be so connected to the throttle valve Vthat the ports 52 remain completely open when the throttle valve is entirely closed and said ports 52 will be completely covered only when the throttle valve is in fully open position. The spirit of the present invention, as before mentioned, is the provision of automatic means for varying the ratio of the components of the fuel mixture in accordance with requirements.

In operation, when the engine to which vthe carburetor is attached is idling, the throttle v alve 44 is in-closed or nearly closed position as is usual, thus preventing the passage of fuel mixture from. the standpipe 12 through the discharge outlet 18 or at least, reducing such passage to a minimum. In this position of the throttle valve, the cylindrical valve 54 in the standpipe covers the apertures or ports 52. As the throttle valve is rotated slightly pn rod 46, the air passing from air chamber 2O through venturi 16 draws fuel through the standpipe into the venturi and to the engine through the d1scharge passage. Air which enters the well 6 through ports 22 passes upwardly around.

valve 54 and gradually uncovering the port-s' or apertures 52 whereby the passage of fuel through the standpipe and past the apertures 52 serves to draw additional air through said ports 52 into the standpipe where it mixes with the fuel mixture passing upwardly through the standpipe; thus producing a leaner mixture of air and gasoline prior to its admission to the venturi where air passing into the venturi around the standpipe end mixes therewith. It will also be apparent that due to the uncovering of the ports 52, there will be a reduction in the amount of fuel which is drawn upwardly from the nozzle through the standpipe and consequently the fuel mixture is not a normal mixture, or in other words, is leaner than the mixture which would ordinarily be drawn through the standpipe with the throttle valve in partly open position.

It will be apparent therefore that the specific fuel mixture expelled from the standpipe varies proportionately to the throttle valve opening, thus providing variable leaner fuel mixturesat certain speeds of the engine; more particularly at such speed of the engine corresponding to the partly open throttle position.

Upon further increase of the throttle valve opening, it will be apparent that the arm 64 of bracket 60, to which the links 58 are pivotally connected, crosses the vertical axis of the throttle valve, after which, upon continued opening of the throttle for higher speed of the engine, the cylindrical valve 54 Will rise thereupon gradually covering the ports 52 and providing a rich mixture for the engine at said higher speeds, or to be more exact, the cylindrical valve covering the ports 52 will prevent the admission of additional air to the mixture in the standpipe and thus result in a normal fuel mixture for the engine at the higher speeds of the latter.

It is believed obvious that those skilled in the art will recognize that the fuel mixture is rich at maximum vacuum, and is gradually leaned as the vacuum decreases to a predetermined value and is thereafter enriched on a further decrease in vacuum; this cycle being effected by means of and in accordance with the movement of the throttle valve. Y

lindrical valve 54 will first lower to uncover the ports 52 and admit additional air into the standpipe thus varying the composition of the fuel mixture by varying the relative ratios of the components thereof and provide a leaner mixture. Then upon further closing of the throttle valve, the cylindrical valve 54 will again rise to cover the ports 52, as will be apparent.

What is claimed is:

1. In a carburetor, means forming a mixing conduit, a source of fuel supply, a nozzle receiving fuel from said source, a primary mixing chamber receiving fuel and air from said nozzle, al venturi in said mixing conduit, said primary mixing chamber discharging at the throat of said venturi, an air admission port in the wall of said primary mixing chamber, a valve for said port, a throttle controlling the flow through said mixing conduit, a crank mounted on the inlet slde of said throttle, a connecting rod for said crank and said valve, said crank bein so mounted with respect to the movement o the throttle as to cross the dead center when the throttle is approximately half way open.

2. In a carburetor, a constant level fuel chamber, means forming a mixing conduit, a nozzle leading from said fuel supply chamber, means for mixing air with said fuel prior to its discharge from said nozuzle, a primaryv mixing chamber of larger diameter than said nozzle and in line therewith, the' inlet end of said mixing chamber encircling the discharge outlet of said nozzle and forming a restricted air admission port for increasing the speed of the air stream flowing past the end of said nozzle into said primary mixing chamber, a main venturi surrounding the discharge outlet of said primary mixing chamber, a throttle controlling the flow of mixture through said carburetor, a port for admitting air to said primary mixing chamber between the ends thereof, and means operated by said throttle for controlling said port.

In witness whereof, I have hereunto set my hand.

GEORGE M. BICKNELL.

Upon closing of the throttle valve the cy-

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