US1764711A - Carburetor - Google Patents

Description

June 17, 19.30. w. A. BRAcKE-r Er AL 1,764,711

' CARBURETQR; I

Filed Aug. 8, 1927 2 Sheets-Sheet l 'June 17, 1930. w. A. BRACKET-r ET AL 1,764,711

cARBUREToR Filed Aug. 8, 1927 2 Sheets-Sheet 2 `associated is started,

Patented June 17, 1930 stares PATENT .o1-'rica f WELLBY ALLENBRAGKETT AND wrLLiAM nnwnnn RICHARD, on EVANSVILLE, INDrANn, assIGNoRs r.ro sUNBnAM minerari: MANUFAcrUnINe COMPANY; 0F EVANsvInLn, INDIANA, A conronnrion or' INDIANA 1 cAnBUnnToia i @rating temperature.y This is frequently accomplished by choking the supply of air to the carburetor. TheA degree of `vacuum created in the carburetor by reason of 'the op#v eration ofthe engine is thus increased, and

theiamount of liquid'fuel that is forced into the mixing chamber by exto 'nal atmospheric pressure islilrewise increased. vTl'ierefore, the ratio of the amount of fuel to the amount of air is increased. Y l f l f It is diilicult to regulatethe fuel mixture `automatically where an internal combustion engine is automatically controlled. OurA invention,contemplates the provision of means for accomplishing such regulation, however, but this regulation is accomplished by vary" ing the vrate of fuel supply to the carburetor mixing chamber without varying the rate of air supply.'` i y y Y i Y The principal. object of our invention,

therefore, isl to provide acarburetor comprising means for zuitomatically regulating the ratio of fueland air to be mixed therein when the enginewithV which the carburetor is .i Other objectsand -adyantagesofour inrentioniwill appear from a consideration of thefollowin detailed description in connection with the accompanying drawings, in which: i i, J i

Figure 1 is a top'plan view of a carburetor embodying my invention; i I ,1 Fig. 2 is av Vvertical sectional View` taken along the line H-Hof Fig. 1; i i, i Fig. 3 is an enlarged fragmentaryview in .perspective showing the construction of a float stemutilized l in the carburetorvenibodyf ingmyinvention; i i

partly in section, taken along the line IVhIV of Fig. 1;

. Fig.` 5 is a horizontal sectional View taken along the line V--V of Fig. et; and

` Fig. `6 is a fragmentary .sectional view takenY Von a line corresponding to the line IVe-IV of Fig. 1 and showing one feature of my invention in modified form. Referring to the drawings, thecarburetor embodying our invention comprises a top portion 5 having a horizontal tubular portion 6 of Venturi form extending'thereacross A reservoir member 7 of cup form is secured to the top portion 5 by screws 8 and contains a float 9 that is secured to a vertical stem 10. The stem 10 extends"upwardly fin close-tit. ting relation to an opening 11 in a downwardlygextending portion 12 ofthe vtop portion 5. The stem 10 is adapted to be actuated vertically in the opening 11 but is so fitted therein as to` prevent the` leakage of fuel through said opening around the stem. The opening 11 intersects the Venturi tube 6 kat the central portion thereof and `is in alignment with a similar opening 13 in the upper wall ofthe tube 6. Anupwardly extending tubularportion 14 ofsaid upper wall is adapted `to receive a screw-threaded stop member 15 that is provided at the upper end thereof with a lmurled knob 16 whereby the vertical position of thestop member 15 Vmaybe manually adjusted. A vertical pin 17 is secured to the upper wallof the tube G and. engages the-periphery of the knobfl Vto prevent accidental .movement of lthe stopV` member 15 due to vibration 'o1-other causes. The lower surface of the Vstop member 1.5

Y iforms a cavity 18 thatisi adapted to engage the upperextremity of the stem 10 when the same is ac tuatedupwardly through the open- ,A depressionA 19 forming a cliannelin one side ofthe stem loisadapted to registerwith an inclined passage 20 in the `downwardly extending portion V12 `of lthe lower wallof the tube 6. The depression 19V is shown in the drawings as being of rectangular cross-seci-` tion, butrit is obvious that a channelV of V- Vshaped semicircular or any other desired form of cross-section may be utilized with equal effectiveness. VThe passage constitutes a conduit extending downwardly and transversely to the upper extremity of a vertical conduit 21 that is secured to the downwardly extending portion 12. The conduit 21 extends from this point downwardly through an aperture 22 in the float 9 to a point relatively close to the bottoni of the reservoir 7 A fuel conduit is thus provided from a point near the bottom of the reservoir7 to the center of the Venturi tube 6, and this conduit is adapted to conduct liquid fuel from the reservoir to the Venturi tube, as will be hereinafter more fully described.

The channel 19 is tapered downwardly along the stem 10, as shown in Figs. 2 and 3, to provide a conduit extending from the upper-extremity of the passage 20 the center of the Venturi tube 6, this conduit having a decreasing cross-sectional `areas as the iioat 9 is raised to raise the stem lO'correspondingly. The position of the vstop member 15 is adapted to be adjusted by the knob :i6 'to limit vertical movement of the stem 10, which, therefore, determines the minimum vcross-section of the conduit 19 at the pointwhere this conduit is intersected by the conduit 20.

The Venturi tube 6Y is provided at one extremity thereof with a flange portion 23 that is adapted to be secured tov the intake 'manifold of an internal combustion engine by cap-screws 24.r A throttle valve 25 is provided in the tube 6 near the extremity thereof adjacent the flange 23 and is adapted to be actuated by a stem 26 and disc or dial 27. Anactuating member 28 is operatively rconnected to the disc or dial 27 to permit actuation of vthevalve 25 in any desired manner. A pin 29 Ithat is secured to vthe stem '26 co-operates with two stop- screws 30 and 31 to determine the maximum and minimum openings of the valve 25.

' Air isY supplied to the Venturi tube 6 through a valve 32 inthe extremity of the tube 6 opposite to thev extremity in which the throttle valve 25 is disposed. The valve 32 'may be vadjusted or Voperated 'either automaticallyor manually in any de'sired'man-V ner. Thus, it will be'seen ,that the Venturi tube l6 constitutes a mixing chamber to which liquid fuel may be supplied through the channel' conduit 19 in Vthe stem 10 and to which air may be supplied through lthe valve 32.

The reservoir 7 is adaptedto be supplied VIwith liquid fuel through Aan' aperture 33,

shown in Fig. 5, to which any suitable pipe or conduit may be connected. Such a pipe or conduit will Vordinarily be connected to a 'fuel pump thatv is operated whenever the engine with which the carburetor is associated is in operation. Such a fuel pump will take liquid fuel from any suitable tank or reservoir, which may be disposed below the level of the reservoir 7 lof the carburetor if desired. An aperture 34, which also connects with the interior of the reservoir 7, constitutes an overflow conduit for said reservoir and is adapted to be connected by means of a pipe or conduit 35 tothe main fuel reservoir to permit drainage of excess fuel from vthe carburetor reservoir to the main reservoir. The cross-sectional area of the overflow conduit 35 is of such size as to limit the amount of fuel that may be contained within the reservoir 7 to the level 'at which the aperture 34 connects therewith, which is relatively close to the top of the reservoir. Two apertures `36 and 37 of relatively small cross-sectional area connect the chamber of the reservoir 7 with the aperture 34 at lower levels than that at which the main portion of the aperture 34 connects with the reservoir 7, for a purpose to be described hereinafter. A

A vertical rod 38 extends downwardly in close-fitting relation to an aperture 39 through the top portion 5 of the carburetor, and thence in relatively loose-fitting relation through an aperture 40 in the float 9.

VThe lower extremity of the rod 38 is provided with a liange portion 4l of greater vdiameter than that of the aperture 40 and constitutes a stop or limit to determine the lowermost position of the float wit-hin the reservoir 7. rIhe rod 38 is provided with a plurality of indentations or notches 42 near the upper extremity thereof and la resilient member 43 is adapted toco-operate with these 'notches to maintain the rod 38 in the position in which it is manually set. The 'resilient member 43 is secured to the top portion 5 of the carburetor by a screw 44.

It will 4be seen that the rod 38 may be manually adjusted to determine the lowern'iost position of the float 9 as desired and that such adjustment will be maintained by reason of the engagement between one of the notches 42 and the resilient member 43.

Vxlhen an internal combustion engine with which thecarburetor 'embodying our invention is associated is to be started, such engine may be cranked automatically in response to any desired condition and in any well known manner. The fuel. pump -associated with'the engine is thereupon operated and supplies a quantity df fuel to the reservoir 7 andrsuch fuel is conducted from the bottom of the reservoir 7 Athrough the conduit 21, the passage 2O and the channel 19 to the Venturi tube 6, within which the pressure hasvbeen reduced Vby reason of the vcranking ofthe engine., The float v9 will l be inits lowermost position, as determined by the vertical position of the rod 38, and the cross-sectional area of the channel 19 Aat the point where this channel is intersected by the passage 2O will be' relatively large.

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Therefore, `a relatively large quantity of fuel is admitted to the Venturi tube 6, where it is mixed with the air admitted through the valve32 to produce a relatively rich mixture. This mixture is supplied to the engine through the throttle valve 25 and the engine will start to operate as soon as coinbustion takes place therein.

As the reservoir 7 is supplied with additional fuel from the pump, the float 9 israised` to actuate the stein 10 upwari'lly.` The cross-section area of the channel 19 at the point of intersection with the passage- Q0 is thus gradually decreased to lessen the amount of fuel that is supplied to the mix* ing chamber within the tube 6. Since the rate of air supply is unchanged, the fuel mixture is leaner, which is' the condition desired as the temperature of theA engine increases. The rate at which the reservoir 7 is filled with fuel is determined by the size and position of the apertures 3G and 37 'through which fuel is permitted to drain back through the overflow conduit to the main reservoir. lt is obvious that by varying the number, size and position of the apertures 36 and 37 the length of time required for the fuel pumpto lill the reser voir 7 with fuel may be adjusted to any desired value Whenthe reservoir 7 isffilled with fuel after the `predetermined desired-time, the float 9 and the stem 10 assume their uppermost positions as determined bythe position of the stop member 15. Under this condition, the cross-sectional area of the channel conduit 19 at the point of intersection with the passage 20 is decreased to itsV minimum value and the yfuel mixture is likewise reduced to the minimum desired proportion of the amount of fuel to the amount of air admitted. to the mixing chamber within the tube 6. This minimum value may be determined by adjustment of the knob 16 in accordance with temperature conditions, quality of fuel, or any other desired conditions. p

The ratio of fuel and air to be supplied to the mixing chamber whenv the engine is started may be adjusted-by adjusting the position of the rod 38. During cold weather, for example, the rod 38 may be set at the lowermost position, as shown in Fig. 4 of the'drawings, to permit the great est possible amount of fuel to be supplied to the mixing chamber Within the tube 6 when the engine is started. Under other conditions, the rod 38 may be set at higher positions to decrease the area of the channel conduit 19 at the point of intersection with the passage 20, thereby causing a leaner fuel mixture to be supplied to the engine when the same is started.

The modification shown in Fig. 6 of the drawings, consists in providing an adjust- `able valve member 15 for co-operating with may thus be predetermined by adjusting the valve /lto obtain any desired cross-section of the opening Fremthe foregoingdescription it will` be seen that we have provideill a carburetor comprising means for automatically regirlating the ratio of air and fuel in the comu bustible mixture supplied to an internal combustion engine. The maximum and minimum values of t iis ratio are readily adjustable indepeniilently of each other and the time required for "the ratio to be automatically changed fromv one limit to the other may also be adjusted as desired. An internal combustion engine equipped with a carburetor of this type may therefore. be automatically operated under all temperature conditions and with any available qual-` ity of fuel.

YVhile we have shownand described only one specific embodiment of our invention, it will be seen that various changes and modifications may be madein the details of structure thereof without departing from the spirit and scope of our invention. Therefore, we desirepthat ourinvention be limited only bythe prior art and the scope of the appended claims. 1

We claim as our invention:

1. A carburetor comprising a mixing chamber, means for conducting air and fuel thereto, a fuel reservoir containing a float, and means controlled by the float for decreasing the rate of fuel supply fromr the reservoir to the mixing chamber when the amount of fuel inthe reservoir is increased.

2. A carburetor comprising a mixing chamber, means for conducting air andA fuel thereto, a fuel reservoir containing afloat, and means controlled by the lioat for pei'- mitting an increase in the rate of fuel supply from the reservoir to the mixing chamberwhen the amount of fuelin the reservoiris decreased.

3. A carburetor comprising a` mixing chainber,ja fuel reservoir containing a float, a fuel conduit connecting the fuel reservoir and the mixingchamber, a valve in said conduit the degree of; opening of which is decreased by upward movement of the float, and adjustable means for limiting thermovement of the float. .Y

4f. A carburetor comprising a mixing chamber, a fuel reservoir containing a vertically movable float, a fuel conduit con` necting the fuel reservoir and the mixing chamber, Va valve in said fuel conduit the degree of opening of which is decreased by upward movement of said float and adjustable means for limiting 'the upward movement of said float.

5. A carburetor comprising a mixing chamber, a fuel reservoir containing a vertically movable float, a fuel conduit connecting the fuel reservoir and the mixing chamber, a valve in said fuel conduit the degree of opening of which is decreased by upward? movement of said float and adjustable means for determining the lowermest position of said float.

6. A carburetor comprising a mixing chamber, a fuel reservoir containing a vertically movable float, a fuel conduitconnecting the fuel reservoir and the mixing chamber, a valve in said fuel conduit the degree of opening of which is decreased by upward movement of said iioat, adjustable means for limiting the upward movement of said float, and adjustable means for determining the lowermost position of said float.

7. Av carburetor comprising a vmixing chamber, a fuel reservoir beneath said mixing chamber, a vertically movable float in said fuel reservoir, a fuel conduit connecting said fuel reservoir and said mixing chamber and having a vertical portion, a vertical stem for the float extending upwardly through the vertical portion of the fuel conduit and through the mixing chamber and having a channel of varying crosssection therein to control the rate of fuel iow through the fuel conduit in accordance with the position of the float, and an adjustable stop member in the upper wall of the mixing chamber' for engaging the upper extremity of the float stem to limit the upward movement of the float.

8. A carburetor comprising a mixing chamber, a fuel reservoir beneath said mixing chamber,` a vertically movable float in said fuel reservoir, a fuel conduit connecting said fuelV reservoir and said mixing chamber and having a vertical portion, a vertical stem for the float extending upwardly through the vertical portion of the fuel conduit and through the mixing chamber and having a channel of varying cresssection therein to control the rate of fuel How through the fuel conduit in accordance with the position of the float, and a screw-threaded'member co-operating with a screw-threaded opening in the upper wall of the mixing chamber for engaging the upper extremity of the float stem to limit the upward movement of the float.

9. A carburetor comprising areservoir member of cup form, a cover member therefor having a substantially horizontal hollow cylindrical portion forming a mixing chamber, said cylindrical portion having a vertical rpassageway and an inclined'intersecting passageway in the lower lwall thereof, a vertical stem extending through said vertical passageway, a' iioat disposed within the reservoir member and secured to the stem, and a conduit secured to the cover member in connection with the inclined passageway therein, extending downwardly through an aperture in thefloat and opening into the reservoir chamber near the bottom thereof.

10. A carburetor comprising a reservoir member of cup ferm, a cover member therefor having a substantially horizontal hollow cylindrical portion forminga mixing chamn ber, said cylindrical portion having a vertical passageway andan inclined intersecting passageway in the lower wall thereof, a vertical stem extending through said vertical passageway, said stem having a channel of varying cross-section therein in register with the inclined passageway to form conduit extending into the mixing chamber', a float disposed wit-hin the reservoirv member and secured to the stem, and a conduit secured to the cover member in connection with the inclined passageway therein, extending downwardly through an aperture in the float and opening into the reservoir chamber near the bottom thereof. Y

11. The method of regulating the ratio of fuel and air to be mixed in a carburetor which consists in decreasing the rate of fuel supply to the mixing chamber when the amount of fuel in the float chamber is increased.

12. n a carburetor, the combination with a mixing chamber, a reservoir adaptedto be filled with fuel and containing a float, and means for supplying fuel to the reservoir, of means controlled by the fioat for decreasing the rate of iow of fuel from the reservoir to the mixing chamber as the amount of fuel in the reservoir is increased, and means for controlling the length of time required to fill the reservoir with fuel.

13. In a carburetor, the combination with a mixing chamber, a reservoir adapted to be filledk with fuel and containing a Heat, and means for supplying fuel to the reservoir, of means controlled by the float for regulating the rate of flow of fuel from the reservoir to the mixing chamber and means comprising an overflow conduit for controlling the length of time required to fill the reservoir with fuel.

111-. In a carburetor, the combination with a mixing chamber, a reservoir adapted to be filled with fuel and containing a Heat, and means for supplying fuel to the reservoir, of means controlled by the float for regulating the rate of flow of fuel from the reservoir to the mixing chamber and an overflow conduit having an opening into the reservoir to limit the amount of fuel that may be contained by the reservoir and another opening into the reservoir to control the length of time required to lill the reservoir with fuel up to said limit.

15. In a carburetor, the combination with a mixing chamber, a reservoir adapted to be filled with fuel and containing a float, and

means :for supplying 'fuel to the reservoir, of means controlled by the float for regulating the rate of flow of fuel from the reservoir to themxng chamber and en overflow conduit having e relatively large opening into the reservoir neer the top thereoI to limit themnount of fuel that may be Contained by the reeervor and having a pluralty of relatively Smell openings into the reservoir below the level of seid relatively large opening to control the length of time required to fill the reservoir with fuel up to the level of said relatively large opening.

In Witness whereof We have hereunto sub- 5 scribe/flour names. v

'VELLB Y ALLEN BRACKETT. WILLIAM EDARD RICHARD.

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