US1718769A - Carburetor - Google Patents

Description

June 25, 1929. w. H. WEBER CARBURETOR Filed March 10 1924 2 Sheets-Sheet 1 w Ill... .llll

IN V EN TOR.

- ATTORNEY.

June 25 1929. w, H, WEBER 1.718.769

GARBURETOR Filed March 10, 1924 2 SQeets-Sheet 2 I 60 T Hi; Hi w c ml; M w i w .97 .17

g if INVENTOR.

' ATTORNEY.

lf atentetl dune ilti, i929 1,718,769 PATENT OFFICE.

WALTER H. WEBER, F HIGHLAND FARR, MICHIGAN, ASSIGNOR TO DETROIT LUBRI- GATUH GUMPANY, 01b DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

GARBURETOB.

Application filed March 10, 1924. Serial No. 698,013.

lily invention relates broadly and generally at 8, into a nipple 8, preferably formed into carburetors, and particularly to those of the plain tube type.

The primary object of the invcntlonus to provide a carburetor of the type mentioned with improved means for assuring substantially correct mixture porportions of liquid fuel and air throughout the range of operative engine speeds and loads.

Tlhe invention consists in the improved construction and combination of elements, to be more fully described hereinafter, and the novelty of which will be particularly pointed out and distinctly claimed.

lln the accompanying drawings to be taken as a part of this specification, have shown a preferred embodimentof the Invention, and in which drawings, Figure l is a vertical central section through my improved carburetor;

Fig. 2 is an enlarged central vertical section through a nozzle assembly embodying my invention, and as shown in Fig. l;

Fig. 8 is a section on the line 33 of 2;

Fig. t is a section on the line t-l of Fig. 2;

Fig. b is a section on the line 5-5 of Fig. 2;

fig. 6 is a view similar to Fig. l, but showing a modified form of nozzle;

Fig. 'l is a view similar to Fig. l, and showing another form of nozzle, and

8 is a detailed view in elevation looking from the right of lFig. l, showing the strangling means associated with the nozzle.

Referring to the drawings by characters of reference, 1 designates a carburetor body which may be of any design suitable for the purpose, the same having a restricted passageway preferably formed by a Venturi tube tlne end of the body forming the passagewa y mentioned constitutes an air inlet 2, and the other end 2 constitutes an outlet leading to the engine intake, not shown. The outlet F?" is provided with throttle valve 3 preferupon central transverse shaft to l t chamber to a noaalc within the re or body, ltrality in, st which, 'l', is se tegral with the base of the body 1, in which plug is drilled a calibrated orifice 9 communicating with said conduit 5 heretofore de scribed. The innermost tube 10 of the nozzle is arranged concentric with the tube "f heretofore described, and passes through a central hole 11 in the top of said tube 7, and at its lower end is threaded into a counterbored hole 12 in the plug 8 and located above and in communication with the orifice 9. The tube 10 extends for a suitable distance beyond the upper end of said tube 7, and has its upper end 18 located adjacent the throttle valve 3 and preferably so as to open through a central hole in the latter, the tube l0 thereby constituting an idling and low speed passageway for the fuel, through which an explosive mixture may be projected into the outlet 9 when the throttle 3 is closed. in the end of u the tube 10 above the throttle valve is a plug 14 containing a restricted outlet orifice l5. Said tube is also provided with an orifice 16 in its side wall for admitting air from below the throttle to the interior of tube 10 to emulsify the fuel passing therethrough, as will be hereinafter described.

1? designates a downwardly tapered tube surrounding and adjacent the innermost tube 10, and spaced therefrom to form an annular chamber 18 of progressively decreasing crossscctional area from the upper to the lower end thereof. The upper end portion of the tube l?! is flared outwardly, as at l9, to provide a flange, the periphery of which is arranged in contact with the inner surface of the outer tube-7, and the lower end of the tube l? is similarly dared to provide a flange 20 to contact with the inner surface of the lower end of the tube 7. A fourth tube at is placed between the tapcring tube 1? and the outermost tube 'f, and is provided with longitudil u external grooves see lFi uni 4mm l cal air ducts treniities of the tu tube if, as shown in k suitably secured tog u soldering, or other means, the fluid tight struc I in the wall which the liquid fuel Ell Eli

llllll 2 through discharge. holes 26 peripherally arranged in a rounded or cupped portion 27 at the upper end of the outer tube 7.

For the purpose of affording communication from the atmosphere to the main well 18, the outer tube 7- is provided, preferably adjacent its base, with air holes 28 which communicate with the lower ends of the vertical ducts 23 formed by the grooves 22 in the tube 21. At the upper end of the tube 21 are ports 29 located above the normal fuel level and at fording atmospheric communication between the ducts 23 and the annular chamber 30 located between the tapered tube 17 and the tube 21.

The tapered tube 17 is provided with ports 31 also located above the normal fuel level and allowing communication between the chamber 30 and the fuel well 18. These holes are preferably of such size and number as to admit the requisite quantity of air to emulsify the fuel as it issues through the discharge orifices 26 under the suction of the engine. The tapered tube 17 is also provided with a hole 32 located near the lower end portion thereof, for the purpose of affording atmospheric communication with the lower end of the main fuel well 18. This orifice or hole 32 determines the rate at which the liquid fuel lowers in the Well 18 and, therefore, the cross-sectional area of liquid fuel exposed to the .aspirating air entering the holes 28. 29 and 31. The area and position of hole 32 lengthwise of the tapered well 18 can be varied to meet the requirements of the motor upon which the carburetor is to be used. For example, for average automobile motors, the size of the hole 32 is such that the liquid level of the fuel in well 18 will not be lowered to approximate the level of said hole until the engine speed has reached approximately 800 revolutions with the throttle wide open, giving a car speed of about fifteen miles per hour.

The port 16 in the idling tube is located at a suitable point between the fuel outlets 26 from the main nozzle and the throttle plate 3, which port 116 communicates with an air tube 33 seated in the wall of the carburetor body and having a port 34 communicating with one end of an air duct 35 extending through the body, and the opposite end of which opens, as at 36, into the suction passage 2 at a point above said air tube. 33, but below the throttle. Threaded into the body is a screw-plug valve 37 adapted to cooperate with the port 36 in order to regulate the area thereof and thereby control the flow of air therethrough. It will be understood that the tube 33 is closed at its inner end and is sealed around the idling tube 10, the well 18 and the chamber 30 to a height corresponding with the level of the fuel in the float chamber, that is just below the openings 29 as indicated by the broken line LL on Figs. 1 and 2. During idling, and at low speeds, when the throttle is nearly closed, liquid fuel is delivered to the engine only through the inner tube 10, since this tube extends above the throttle. The fuel passing from tube 10 is emulsified by the air which onters tube 10 through the port 16, tube 33, duct 35 and valve regulated port 36. As the throttle is opened wider and the speed of the engine increases, the suction at the throat of the venturi increases, causing the fuel to be drawn or aspirated through the main discharge orifices 26, this fuel being emulsified by the air which enters through the holes 28 in the outer tube, passes up through the vertical ducts 23 and is admitted above the fuel in the well 18 through the ports 29 and 31.

At low speeds when the suction in the suction passage is relatively low the level of the fuel in the main well 18 remains near the upper end thereof at apoint just below the openings 29 and a relatively larger surface area of fuel is, therefore. exposed to the aspirating effect of the air passing through the holes 31 and the Vent-uri tube, with the consequent effect of supplying the somewhat richer mixtures required for low speed operation. As the speed is progressively increased, the level of the fuel in the main well 18 is lowered approximately to hole 32, due to a difference in pres sure brought about by the atmospheric communication afforded by holes 28, ducts 23, ports 29, chamber 30 and hole 32, and because of the tapering construction of the well which causes the cross-sectional area of the well to gradually decrease to the level of hole 32, the surface area of the fuel is diminished. The minimum surface area of the liquid in the well 18, when the motor is running at higher speeds, may be secured by properly locating the hole 32 lengthwise of the tapered well. By the construction described it is assured that the quantity of fuel discharged is proportional to the cross-sectional area of the liquid fuel P .posed to the aspirating effect of the air passing through the Venturi tube, and, therefore. my invention effectually overcomes the well known tendency of a single jet carburetor to supply an over-rich mixture at higher engine speeds, and assures substantially correct m x ture proportions of liquid fuel and air throughout the range of operative engine speeds and 10a. s.

When the engine is running idle and the throttle plate 3 is closed, the air pressure beneath the throttle plate will be substantially atmospheric. and there will be a depression on the engine side of the throttle plate. Under these conditions air will be drawn through the port 36. into the duct 35', the bore of the tube 33, and through the port 18 into the idling natures tube 10 to min with the liquid fuel flowing through the latter, and thus provide a proper mixturev for the engine while running idle.

The construction just described also serves to prevent any lag in liquid fuel flow btween the time the throttle plate is opened and the beginning of fuel flow from the main nozzle. ll hen the throttle is suddenly opened from the idling or nearly closed position, the air flowing through the suction passage 2 passes through the space between the throttle plate and the wall of the passageway at a co1nparalively high velocity, and passing the port 36 serves to draw the liquid fuel from the idling tube through the port to, tube 33, passage and said port as, thereby enriching the mixture for a short time so that there is no lag in the supply of proper mixture between the time the throttle plate is opened and the main nozzle begins to function.

shown in Figs. 1 and 8, the preferred embodiment of the carburetor may be, and

-preferably is, provided with a movable till strangling device for chokingthe passage through the carburetor when the engine is started. As shown, this device may consist of a cone-shaped member 'l slidably mounted upon the outer sleeve 1 of the nozzle, said device being, during the running of the en'- gine, adapted to rest at the base of the nozzle, but when starting, to be lifted by a suitable yolre l and lover l, said lever being fulcrumed in ears 'l on. the body, and adapted to be operated manually by any suitable con ction to the dashboard of the vehicle.

in the modified construction as illustrated in Fig. 6, a boss 32% projects into the air passageway and has a cylindrical outer tube 39 extending upwardly therefrom. A. tubular plug lid is threaded, as 4:1, into boss 38 and has a tubular tapered upper portion t2 extending through the tube 39 to form an annular chamber therebetween. tapering the portion t2 externally, the Clittl11- ber 4:3 is formed to progressively decrease in cross-sectional area from the top to the bottom. Fuel which is delivered through the lateral passageway 5 enters the bore of the plug 40 through a restricted or calibrated orifice 4a, and is conducted to the bottom of p the well id-through the radial ports to in said portion 42. in the plug portion 42 below said ports 4th is an annular external groove l6, said groove communicating with the external atmosphere through a passageway t7 in the carburetor body, and with the eel 43, by reason of the clearance 45 between the inner wall of boss 38 and the up per portion of plug 40. A cap 48, secured to the tube 3tl, is provided with discharge orifices 49, preferably located opposite the restricted portion of the Venturi tube. The

groove 46 corresponds in function to the port 32 in the form shown in Figs. 1 and 2.

In this embodiment of the invention an idling tube, functioning in the same manner as that heretofore described, is employed. This tube is shown at 50 and is threaded, as at 50*, at its lower end into a seat 51 in the upper end of the plug portion 42. The tube at its upper end projects through a central opening 52 in a pivoted throttle plate 63, the outlet end of said idling tube terminating beyond the throttle plate in the direction of travel of the mixture. 'llhis idling tube is provided preferably with a restricted air inlet 16 constructed and arranged in connection. with an air tube 33 and asso ciated parts, as heretofore described, regard ing tubes 10 and 33.

lln ll ig. 'l" l hare shown another embodiment of the same invention which, in general respects, is similar to that shown. in Fig. ti, except as to the nozzle structure, which will now be described. lln this form, the carbure tor body is provided within the passage 2 with a boss 5a, in which is threaded plug 55 having a calibrated orifice 56 communicating with the passage 5, heretofore de (scribed, and leading to the float chamber.

ln the upper portion of the boss 54; is thread ed, as at 5?, the lower end of tubular nozzle body till having a central. bore 59 which tapers downward from the upper end of the nozzle body toward the lower end thereof. l lntending through the tubular bore 59 just described, is an idling tube 66, the lower end of which is threaded, as at til, into the plug 55, whereby said tube will. be fed liquid fuel through the calibrated orifice 5t and the passage ii. The tube 60 is otherwise arranged and operates as heretofore de scribed, and, therefore, no further specific description thereof is thought. necessary. [ad jacent its lower end the tube 66 is provided with one or more ports 62 correspondingto port 25 in l igs. It and 2 and which communicate with an annular passage between the outer surface of the idling tube and the inner surface of the tapered l ire tid, so that liquid fuel will pass from the idling tube into the lower part of the tapered chamber or bore till. lln this form of the invention an air supply passage tlihtlt, preferably constructed in the same manner as the supply d7 heretofore described, is supplied, and op crates in substantially the same manner as the latter.

lln both of the constructions shown in Figs. 6 and '7, it will be seen that the some novel features are incorporated as embodied in the preferred construction shown in Fig. 1. In both the latter instances, the tapering walls l3 and 59 receive the fuel supply at the bottom thereof, and each ofsueh wells is connected with an air tube communicating with the external atmosphere. lly employment of the. elongated tapered well, I am able in a single well structure to provide for the maximum fuel surface area desirable for slow ltltl speeds, and a minimum fuel surface area desirable for higher speed. The tapered well also provides an expansion chamber beginning at the base thereof, in which the fuel is more efficiently broken up or emulsified than is the case with a plain or cylindrical fuel passage or well.

What I claim and desire to secure by Letters Patent of the United States is 1. A carburetor comprising a suction pas-- sage, a fuel supply reservoir, a fuel nozzle in said suction passage and including a fuel well having a discharge outlet communicating with said suction passage and a fuel supply inlet communicating with said reservoir, an air inlet port to the well near its top and above the normal fuel level therein, said well progressively increasing in cross-sectional area from said fuel supply inlet toward said fuel discharge outlet, said well being adapted to hold liquid fuel substantially at the level of said airinlet port and at a point of its greater cross-sectional area during lower speeds, and a second air inlet port to afford atmospheric communication with said well near its bottom and at a point of smaller cross-sectional area whereby the liquid level in the well is lowered adjacent said second air inlet port and to a point of smaller cross-sectional area during higher speeds.

' 2. A carburetor comprising a suction passage, a fuel supply reservoir, a fuel nozzle in said suction passage and including a tubular member having a discharge outlet communicating with said suction passage and a fuel supply inlet communicating with said reservoir, said tubular member forming a liquid fuel well of increasing cross-sectional area from said fuel supply inlet toward said discharge outlet, an air inlet port for said tubular member adjacent its upper end and above the normal. fuel level therein, said well being adapted to hold liquid fuel at a point of its greater cross-sectional area and at the level of said inlet port during lower speeds, and

a second air inlet port to afford atmospheric communication with said well adjacent said fuel supply inlet, whereby the liquid level in the well is lowered'adjacent said fuel supply inlet and to a point of smaller cross-sectional area during higher speeds.

3. A carburetor comprising a suction passage, a fuel supply reservoir, a fuel nozzle in said suction passage'and including a tubular member having a discharge outlet communicating with said suction passage and a fuel supply inlet communicating with said reservoir, said tubular member forming a liquid fuel well of increasing cross-sectional area from said fuel supply inlet toward said discharge outlet, said well being adapted to hold liquid fuel at a point near its top of greater cross-sectional area during lower speeds, a restricted fuel feed orifice between said well and reservoir, an air supply port communieating with said well above the normal fuel level therein, and a ort to afford atmospheric communication wit said well near said fuel supply inlet.

4. A carburetor comprising a body having a suction passage, a fuel nozzle in said passage and comprising a tubular element constituting a fuel well provided with a fuel inlet and with an outlet discharging into the suction passage, said well increasing in cross-sectional area from said inlet toward said outlet, a tube surrounding said well and spaced therefrom to form an intermediate chamber, said chamber having communication with said well at a point below the normal fuel level, said tube having an external groove extending longitudinally thereof and also having an opening from said groove into the said intermediate chamber, and a tube surrounding said first-named tube and closing the open side of said groove to form an air duct and having an air inlet delivering atmospheric air into said air duct.

5. A carburetor comprising a body having a suction passage, a fuel nozzle in said passage and comprising a tubular element eonstit-uting a fuel well provided with a fuel inlet and with an outlet discharging into the suction passage, said well increasing in crosssectional area from said inlet toward said outlet, a tube surrounding said well and spaced therefrom to form an intermediate chamber, said chamber having communication with said well at a point of smaller cross-sectional area and below the normal fuel level of said well, said tube having an external air duct extending longitudinally thereof and also having an opening from said air duct into the intermediate chamber at a point above the normal fuel level in the well, said well having an air port communicating with said intermediate chamber at a point above the normal fuel level in the well, and a tube surrounding said first-named tube and having an air inlet delivering atmospheric air into said air duct.

6. A carburetor comprising a body having a suction passage, a throttle controlling the suction passage, a main nozzle including a fuel well having an outlet discharging into the suction passa e beneath the throttle, an idling tube exten ing longitudinally through said fuel well and having a discharge outlet above that of the main nozzle, means for feeding fuel to said idling tube and to said well, said idling tube having a port above the main nozzle and below the discharge outlet in the idling tube,a by-pass passage having a port opening into the suction passage beneath the throttle when closed, and a tubular member extending across the suction passage and conmeeting said by-pass passage with said port in the idlin tube, the arrangement and construction being such that during idling position of the throttle air passes from the suction passage through the by-pass passage and said tubular member into the idling tube, and during a portion of the travel of the throttle from closed toward open position fuel passes from the idling tube through said tubular member and by-pass passage and is discharged from the latter into the suction passage beneath the throttle. v

' 7. A carburetor comprising a body having a suction passage, a throttle controlling the suction passage, :1. main nozzle including a fuel well having an outlet discharging into the suction passage beneath the throttle when closed, an idling tube extending longitudinally through said fuel well and having a discharge outlet above that of the main nozzle, means for feeding fuel to said idling tube and to said fuel well, said idling tube having a port above the discharge from the main nozzle and below the discharge outlet in the idling tube, a by-pass passage in the side Wall of the suction passage and having a port at one end opening into the suction passage beneath the throttle, and a tubular member connecting the other end of said by-pass passage with said port in the idling tube, the arrangement and construction being such that during idling position of the throttle air passes from the suction passage through the by-pass passage and tubular member into the idling tube, and during a portion of the travel of the throttle from closed toward open position fuel passes from the idling tube through said tubular member and bypass passage and is discharged from the latter into the suction passage beneath the throttle.

In testimony whereof I have hereunto subscribed my name.

WALTER H. WEBER.

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