US1586684A - Carburetor - Google Patents

Description

F. C. NIOCK CARBURETOR June 1 1926 Original Filed March 18, 19

3 Sheets-Sheet 1 June 1 1926.

F. c. Mock CARBURETOR original Filed March 18, 1916 s Sheets-Sheet 2 IIIfIFrlhHIItIII IIiIiIl- By l I .YT Z/ Patented June 1, 1926.

we "r MOCK, OF CHICAGO, ILLINOIS, ASSIGNOR TO STROMBERG MOTOR DEVICEfil COMPANY, OF CHICAGO, ILLJN 018, A CORPGRATION OF ILLINOIS.-

caanunnron.

'Application filed March 18, 1918, Serial No. 85,004. Renewed October 29, 1925.

My invention relates to carburetors for internal combustion engines and is concerned particularly with what 1 term an economizer whereby, during certain parts of the range of variable suctions to which a carburetor is subjected in automobile and allied practices, the flow of fuel is cut down or retarded.

lthough it will be clear to those skilled in the art that the features of my invention, as set forth in the appended claims, may be employed in other types of carburetors, I have chosen to illustrate and describe my invention in connection with that type com monly known as a plain tube carburetor, as generally shown in my copending application, Serial No. 47,385, filed August 25, 1915. In the specific aspects of that form It economize by the mechanical needle valve.

line .6-6 of ligures 3 control of the port between the fioat chamber and the feeding nozzle arrangement, while in the present form I economize by a controlled back suction-that is, by controlling the pressure on the liquid fuel in the float chamber-in a certain way, as will be variously set forth in the claims.

In the accompanying drawings: Figured is a side elevational view of the carburetor of my invention;

v Figure 2 is a plan view of the structure of my invention, parts being broken away and shown in section to clearly reveal the structure thereof;

Figure is a. vertical, axial sectional view thereof, taken on the line 3--3 of Figure 2 and looking in the direction indicated by the arrows; I

Figure 4; is a vertical, cross-sectional view taken on the plane of the line 4 i of Figure 2 and looking in the direction indicated by the arrows;

Figure 5 18 a cross sectional view taken on the plane of the line 5-5 of Figures 3 and 4 and looking in the direction indicated by the arrows; and

Figure 6 is a crosssectional view of a portion thereof, taken on the plane of the and 4 and looking in the direction indicated by the arrows.

Referring first to Figure 3, it will be seen that I provide a carbureting chamber 9 suitablv formed in the casing 10, which provides a passage from the air-inlet 11 to the mixture-outlet 12 A main Venturi tube 13 nism 20, operated by a float 21, controls the entry of liquid fuel, such as gasoline,into the float-chamber 19 by way of the pipe 22, the float thus maintaining a constant level at approximately the dot-anddash line w-w.

From Figures 2 aud t it will be seen that between the float-chamber and the main casing 1 provide two wells, a primary well 23 and an accelerating well 24, the relative positions being best shown in Figure 4. Y The primary well 23 is connected with the floatchamber 19 by way of passageways 25 and 26. 7

From Figures 3 and 4 it will be seen that. a nipple 36 is disposed within the primary well 23, and a tube 37 is disposed within this nipple so as to form a central passageway 38 and an annular passageway 39. An aperture .0 admits gasoline, assuming that to be the liquid fuel employed, from the primary well 23 to the central passageway 38, and

an aperture 41 admits gasoline from the primary weli' 23 into the annular passageway 39, both of these apertures lying below the normal level of the fuel, and the latter aperture being mainly adapted for the reverse passage of air for a purpose to be described presently.

The tube 37 passes upwardly and connects exclusively with a passageway 42 near the upper end of the carburetor, which passageway communicates with a nozzle 43 in a plug 44 iusertable in the casing 10 at a point in proximity to the closed position of the throttle, as will be pointed out. A bypass port 45 connects the carburetin chamher 9, which lies below the throttle, with the passageway42, and this connection is controlled by means of a needle-valve 46 adjustable from the outside by means of the adjusting screw 47, a snap-spring 48 being provided to hold this adjusting screw in any means of the passageway the atmosphere by Venv air-passage, as iclcarly shown in Figures 3 and but leaves ample passage :01 air .around it. Slightly above its most restricted portion this secondary Venturi tube is provided with an annular groove 54, from which fuel jets 55 extend inwardly and radially, these jets being, preferably, distributed equidistantly upon the inner periphery. The annular groove 54 is connected with the primary well 23 by means of the passageway 56, it being noted that the fueljets 55, 55 lie abovethe normal level of the gasoline, while the lower end of the passageway 56 lies below it.

Upon the outside of the carburetor, as shown in Figures 1 and 2, the shaft 17, upon which the throttle-valve 16 is mounted, is provided with a cam 57 which has the circular periphery 58 concentric with the axis of the shaft, this cam-surface being complete except for the depression 59, which comes into play at a. certain time, as will be described later.

Mounted upon a pivoti-pin 59 upon the outside of the casing is a bell-crank lever having three arms, 60, 61, and 62. The arm GO extends upwardly and at its upper end is provided with a roller adapted to ride upon the surface 58. The arm 61 extends horizontally and has its end bifurcated at In the top of the float chamber a restricted air inlet 27 is provided, this air inlet being in the way of an opening through a plug which is interchangeable so the gauge of the opening may be changed, if desired.

The float chamber is provided with an e tcnsion 28 on the side of the carburetor upon which the bell crank lever is provided. This extension is clearly shown in Figures 2 and 44 In the top of this extension, an air inlet port 29 is provided, this air inlet port being controlled by a valve 30 carried upon an upwardly ext-ending valve stem 31. The, air inlet port 29 crnmnuuicatcs with the atmosphere by way of the port The valve stem 31 is guided in a screw plug 33 between which and the valve, helical spring 34 is disposed, and at the top of the stern 31 an adiustable nut. 35 is provided, this adjustable nut being hold in position by means of the loci; nut 35: The bifurcated ends 63 of the arm 61 of the hell crank lever embrace the valve stem 31'. between the plug 33 and clear that the valve 30 will be allowed to close. Again, when the roller 60 rides upon the portion 58 of the cam, the valve 30 will be in its uppermost position. Above the level of the gasoline in the float chamber 19, a passageway 30 connects the float chamber with the' interior of the sccondary Venturi tube 52, as clearly shown in Figure 5, the metering of the connection between the interior of the secondary Venturi tube 52 the float chamber, above the a level of the fuel therein, being determined by the restricted port 30 It will now be sccn that: a reduction'in pressure within the Venturi tube 52 will be transmitted either wholly or in part, depending upon the re- '9 strict/ion of the port 30, to the float chamber 19, above the liquid fuel therein. Since the atmosphere inlet 27 is restricted, this reduction in pressure will be effected, when the "valve 30 is closed, thus cutting down the pressure on the gasoline or other liquid fuel to less than atmospheric pressure. hen the valve 30 is opened, the atmosphere inlet into the gasoline chamber is so large that atmospheric pressure prevails upon the liquid fuel in spite of the presence of the passage way 30, 30' and any suction therethrough; Thus, during such time as the valve 30 is closed, the flow out of the float chamber is retarded which means such period as the roller 60 lies in the depression 59.

The shaft 15 of the intake-valve 14 is providedwith the rising cam 65, which is fol- Y lowed by a roller 66 on the arm 62 of the bell cranl: lever. As illustrated in Figure 2, the shaft 15 is provided with an operating lever 66' at its opposite end, this operating lever being adapted to be connected with adjusting means, usually mounted on the dash of an automobile. This is a temporary dash adjustment, and under special conditions, when a change is to be compensated for, the air may be restricted and simultaneous] the flow of gasoline into the primary we 23 may be maximum, regardless of the position of the throttle 1.

The accelerating well 24, which has hereinbefore been referred to, is fed directly from the float-chamber 19 by means of the restricted passageway 67, shown in l igures' 3 and 6. A tube 68, which depends from a screw-plug 69, threaded in the top of this well, is placed concentrically in the well, the interior of this tube being connected hi 4 'means of )orts T0 with an annular roove messes The tube 68 is provided with a series of -ports 74, arranged in vertical succession very low running, the throttle is close along the length of the tube, and, preferably, equidistantly spaced apart, as shown in Figure 4. In this figure the dot-and-dash line indi ates the fuel level inthe float chamber, and under ordinary conditions, the uppermost of these apertures lies above this fuel level. An opening 75 permits the entry of air from the float chamber into the space surrounding the tube 68, this opening being considerably smaller than passagway 30,

say one quarter the diameter thereof.

The operation of the device is as follows: When there is no suction the gasoline stands at a common level in the float chamber, the two wells, and the associated passageways. In starting, the response of the fuel depends upon the positioncin which the throttle is maintained when the engine is cranked, butit will sufiice as a general statement to say that gasoline goes to the engine from the nozzle 43 and also from the fuel jets 55, 55, since, at starting, collected fuel stands in the passageways leading to these nozzles, and there will be a desirable excess of fuel to compensate for the coolness of the engine-cylinders, the lag of the gasoline in response to suction, since the gasoline is heavier than air, andthe consequent excess of air. n

In assuming now a condition of idlin or as far as it can be, in which position, as shown in dotted line in Figure 3, the nozzle 48 may feed over the throttle. Under these conditions air entering the main air-inlet passes upwardly through the Venturi tubes and into the passageway 45, where it goes into the passageway 42, mixing with the rising gasoline and going on to the engine. It will be seen that the outlet of the nozzle 4 is in a slight recess and the result is that there is a slight shunt path for air past the nozzle. This air, of course, goes to the engine with the mixture which comes from the nozzle 43. Under these conditions the reduction in pressure below the throttle is so slight that no teed effect is had upon the jets in the sec-- ondary Vonturi tube. The needle valve 46 is set for the proper admission of air in or der to secure the best mixture for idling and low running. it being evident that this mixture may be dctcrn'lincd-indepcmlonth of consideration as to higher running. ll'hcn the throttle is in this idling or low-run- &

ning position the roller 60 on the hell crank lever on the outside of the carburetor rests upon the portion 58 of the can'l-surface and consequently, as before described, the valve 30 is in its uppermostposition, giving a full supply of gasoline. If, as for instance in colder weather, a somewhat richer mixture is desired under the circun'ist-ances, the dash adjustment may be manipulated to slightly close oil the air in the main air inlet 11..

If it be now assumed that the throttle is gradually opened, it will be seen that'the first etlect, which will be of very short duration, however, will be a temporary re striction of the lower branch of the slight shunt. which has been referred to, and a slight enlargement of the upper branch thereof, this resulting in a momentary increase in the-suction on the nozzle l3, with a slight reduction in the amount of air passing thereby, thus slightly enriching the mixture, in accordance with the slightly-advanced position of the throttle.

As the throttle is opened wider, the suction. at 43 decreases and the issue therefrom decreases correspondingly, but at the same time the suction is increased below the throttie and the jets 55, come into play. It will be remembered that up to this time the jets 55 have been practically inert, for not only has there not been sufiicientinfluence to raise the level of the gasoline in the passage. way 56 toward the jets 55, but. the level has actually been lowered by the withdrawal of fuel through the aperture 40 and upwardly through the central passageway 38 and tube37. As the throttle is opened, however, and suction becomes effective in the Venturi tube'52, a reverse action takes place and the gasoline rises in the passageway 56 to the point of issue from the jets 55, 55. Thus, as nozzle 43 gradually recedes in action with the opening .movemcnt oi the throttle. the jets 55, increase in action.

It will be seen that in the annular passageway 39, there is a certain amount of fuel above the aperture 41 when the suction is not present. to draw it out; but as soon as suction does become ctlectivethis fuel is drawn out and thereafter air, entering by way of the passageways 51, 50 and 49, bleeds into the gasoline supply to the jets 5s, 55. I

During this description of the operation of the jets 55, 55, it is opportune to refer to the double-venturi constructioirwhereby the usual vcnturi effect is secured within the secondary venturi 52,- while the primary Vcnt-uri tube 13 has a similar supereflcct upon the secondary Venturi tube as a nozzle. The result is a thorough vaporization and a complete pick-up of the fuel i'cd from the jets, there being in each stage a sull'icici-itly-rcslriclcd passageway so as to maintain the desired reduction in pressure iii in order totake up all the fuel, whereas the total air passageway is snllicient for the demands of the engine. Since the jets are in the restricted portion of the inner Venturi tube and the inner Venturi tube terminates slightly above the most restricted portion of the main Venturi tube, their action is greatly multipled over that occurring in a single venturi construction.

During this period of intermediate running less fuel than the suction would draw is entirely sufiicient for the engine and the natural flow may be restricted for the sake of economy since power at this time is not the main consideration. On the other hand it would be detrimental to permanently restrict the flow since then power would not be available. In other words, power and economy can not be secured with the same mixture and I therefore change the mixture to correspond to changed conditions. It is during this temporary period that the depression 59 in the cam 57 comes into play, so that, as before described, the valve 30 may move to its lowermost position to make the back suction effective to reduce the flow of gasoline from the float-chamber into the primary well 23. At the same time, the air which enters the fuel passageway by way of the aperture 41, as has been described, displaces gasoline to a small extent to keep down the supply.

As higher running takes place, however, the valve 30 must again be raised to return to the position of maximum power, and this, as has been described, is provided for by the riding of the roller 60 upon the surface 58 of the cam 57, maintaining the valve 30 in its uppermost position throughout the remainder of the range. It is important, however, in this connection, to point out that, as the higher'suctions are attained, more and more air is bled in through the aperture 41 and proportionately gasoline is displaced, so that, although more gasoline is necessary on the higher running the provision of more in proportion is prevented, and, a matter of fact, overbalanced, so as to make the mixture somewhat leaner on the higher speeds. I

I come now to a consideration of the accelerating well. What I desire is a temporary surcharging of the mixture with gasoline lpon acceleration, that is, at the beginning of a period of increased suction. This desirability follows from the natu-ra'l inertia of the fu l from the main source, and the lag in response to suction with which the t red or" fuel. being heavier than air,- follows the position of the throttle; it is also due to the increased effort of the engine at that particular time. It is obvious that this extra feed of gasoline should be merely temporarv, since. once the increased suction as become effective on the main source, the

conditions are steady and further additional gasoline would be excessive. it will be seen that suction at the accelerating nozzle 73 is transmitted back through the passageways 72, ll and T0 to the interim of the tube (38. This accelerating well does not feed on the lower suctions for two reasons: first, be cause the nozzle 73 is at a higher plane than the main jets, and also because the uppermost apertures 74 in the tube 68 partly satisfy the suction, and it is not until this suction is not satisfied by the open apertures that gasoline responds.

In assuming an act of acceleration, it will be clear that a sudden increase in suction will be attended by an additional charge of gasoline from the nozzle 73. the size of this additional charge depending upon the amount of the increase. This regulation of the charge is due to the successive openings 74. For instance, when the suction reaches a point where it is not satisfied by the first bleeders 74, there will be a response of gasoline to the extent of the fuel above the second bleeders. Thi's uncovers the second bleeders, and if the two bleeders together satisfy the suction which has thus been attained, no further gasoline will issue from the accelerating well except that which is drawn out to maintain the level where it has been brought. In other words, then gasoline flows out as fast as it flo s in. Gn the other hand, if these two hleeders do not satisfy the suction, more gasoline will go to the carbureting chamber until the third bleeder is uncovered, and then again the test as 2. whether more gasoline is to go to the carbureting chamber is whether on not the three bleeders, or three sets of bleeders, satisfy the suction. Y 1

It will also be clear that. if the increased range of suction is maintained, the level in the accelerating well will be maintained at the point which was assumed when acceleration took place. Further acceleration to a still higher range is merely/a matter of flll'c ther similar action, as has been explained. If the suction is decreased, obviously the gasoline will rise by gravity head from the" float-chamber to balance the decreased suction and a repeated acceleration means mere- 1y a repetition of the operation which has been set forth.

Under any circumstances, the temporary dash adjustmentis available to'cut dc Wn the air and give maximum gasoline for any condition at 1 hrottle. It will be under-v stood, of course, Quit this adjustment is utilized as is common automobile practies. to correct temporary conditions.- The adjustment for idling is determined by the needle valve 46.. Once determined for a particular engme, th se"ad3ustments need no attention except for a marked change in climate or in the quality of the gasoline.

As before stated, for temporary conditions, such as starting in cold weather, the dash adjustment is utilized to correct the action.

I'claim: A

1. In a carburetor, a carbureting chamber having air and fuel-inlets and a mixtureoutlet, a throttle in said mixture-outlet, a constant level chamber supplying said fuelinlet with liquid fuel, a connection between said carbureting chamber and said constant level chamber over the fuel level therein, a valve controlling the admission of air into said constant level chamber and cam mechanism operating with the throttle for operating said ,valve.

2. In a carburetor, a carbureting chamber having air and fuel-inlets and'a mixture outlet, a throttle in said mixture-outlet, a reservoir supplying said fuel-inlet with liquid fuel, a connection between said cham;

ber and reservoir over the fuel level therein, a valve controlling the admission of air into said reservoir, said valve having a wide- -open position and a restricting position, and

cam mechanism operating with the throttle for maintaining the valve in its wide-open position on low and high suctions, and in its' restricting position on intermediate suctions. 4 3. In a carburetor,'a carbureting chamher having an air-inlet and a miXture outlet, a constant-level chamber having a valve controlled atmosphere inlet and supplying liquid fuel, a fuel-nozzle, a well connected with said constant-level chamber .and said nozzle, said nozzle being fed from said well slightly below the normal level therein, air

being bled into said well slightly below the normal level, a connection between said carbureting chamber. and said constant level chamber over the fuel level therein, a

second nozzle leading to said carbureting chamber from said well at a 'point below the lowest fuel-level therein, another well communicating with the atmosphere through said constant level chamber and fed from said constant-level chamber by a restricted passageway, and a fuel-tube leading from said well to said carbureting chamber at a point slightly above said first named nozzle,

the atmosphere inlet to said carbureting chamber being controlled by the throttle.

4:. In a carburetor, a carbureting chamher having a throttle controlled mixture outlet-and air and fuel inlets, a constant level chamber supplying said fuel inlet with liquid fuel, a passageway communicating with the atmos here, and havin a assa eway F e P g over the uel level therein leading to said carbureting chamber, a lar er atmosphere inlet for said fuel supply c amber, agnormally closed valve controlling said larger atmosphere inlet, mechanical means obnnecting said valve with said throttle, an intermediate well connected between said chamber and said fuel inlet, the fuel being fed 'from said well slightly below the fuel level therein. and a second fuel nozzle leading'into said carbureting chamber and fed from said well below the lowest fuel level therein.

6. In a carburetor, a carbureting cham ber having a throttle controlled mixture outlet and air and fuel inlets, a constant level chamber supplying said fuel inlet with liquid fuel, a passageway communicating I with the upper area of said constant level in,.a valve controllingsaid passageway, a bell-crank lever pivoted on said carburetor for actuating said valve, and means for actuating said bell-crank lever with change chamber for controlling the pressure thereof throttle posit-ion for restricting the flow of fuel u on intermediate suctions and permitting ull flow on high suctions.

7. In a carburetor, the combination of a carbureting chamber having an air inlet and a mixture outlet, a constant level supply chamber, an accelerating well fed from saidsupply chamber, said well being divided, into two compartments by an intervening partition havmg a plurality of apertures therethrough at different levels below the normal fuel level, a fuel delivery passage leading from one of said compartments to said carbureting chamber, and means for restrictedly admitting air to the other of said compartments.

In witness whereof, I hereunto subscribe.

my name this 16th day of-March, A. D. r

' r nANK 0. Moon

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