US1527000A - Carburetor - Google Patents

Description

Feb. 17, 1925.

1,527,000 F. c. MocK CARBURETOR Original Filed Aug. 25, 1.915 3 Sheets-Sheet 1 5 3mm?" Emmk/ C. @fiwmmyj Feb. 11, 1925. 1,527,000

F. C. MOCK CARBURETOR Original Filed Aug. 25, 1915 3 Sheets-Sheet 2 .Feb. 17, 1925.

F. C. MOCK CARBURETOR Original Filed Aug. 25, 1915 3 Sheets-Sheet 5 Y; 1 flvfln H l n w m m 1 m J -InW ,0 2 O & a r W y Java/w worms PatentedFeh. 17, 1925.

w n STAT-ES .PATEN'i OFFICE.

1 rnanxcnoox, or 0310460, rumors, nssmnon 'ro srnomnnae MOTOR nnvrons COMIAN'Y, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINO'IS.

. cnnnunnron.

Original application mu s-t 25, .1915, Serial m. 47,885. ri aled and this application and to the accompanylng drawings, forming apart of this specification.

- My invention relates to carburetors for.

internal-combustion engines and is con- 1 cerned particularly with that class of carburetors now commonly known as plain-tube 5 devices. p a

It is the object of my invention to provide acarburetor for the purpose referred to which willsupply to the-engine at the various speeds and various'loads, such as are attained and assumed in automobile practice, a mixture with the most efiioient proportions of air and fuel, with proper regard to the consideration of economy. Accordingly, it is the. object of my invention provide a device whereby thorough vaporlzation may be had, wherein loading, tliatis the improper accumulation of fuel in the carbureting cliamberiland its subseuent im r0 r supp .to t e engine, may "go avoide d, in which in economical feed of fuel is positively maintained,and in which, upon acceleration, the mixturemay be temporarily surcharged with fuel.

.This application is a division of my oo- 36 pending application Serial No. 47,385 filed August 25, 1915, which resulted in Patent No. 1,404,879 dated January 31, 1922. These and other advantages will become apparen'tto, those skilled in the art as this description proceeds, it. being. understood that t '0 device which I illustrate in the drawings and which I shall describe is an exemplary embodiment of my invention and to which 'I am not necessaril .limited, the scope of my invention being etermined' by the ap ended claim.

In t e accompanying drawings, Figure 1 is a side elevationalview of the carburetor of my invention;

August 9, 1919. Serial No. 316,308.

Figure 02 is avertical, axial sectional view thereof; i j

Figure 3 1s a cross-sectlonal view taken on the lane of the line 3-3 of Figure 2 and'loo g in the direction indicated by the arrows.

Figure 4 .is a cross-sectional view of a portion thereof, taken on the plane of the ins. 44 of Figure 2 and looking in the direction indicated by the arrows;

Figure 5 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 6 is a vertical,cross-sectional view taken on the plane of the line. 66 of Figure 5 and looking in the direction indicated by the arrows;

Figure 7 is a cross-sectional view taken on the plane of the line 7-7 of Figure 6 and looking in the direction indicated by the arrows;

Figure 8 is a detail view which will be referred to. I

Referring first to Figure 2, it will be seen that I provide a carbureting chamber 9 suitably formed in the casing 10, which provides a passage from the air-inlet 11 to the mixture-outlet 12. A main Venturi tube 13 is'set in this passageway, 21. butterfly valve 14 being mounted in the air-intake upon a rotary shaft 15, and a throttle-valve 16 being mounted in the mixture-outlet-upon a rotary shaft 17. A flange18 surrounds the mixture-outlet and is adapted for attachment to the manifold of an internalcombustion engine.

A float-chamber 19 is formed integrally with the casing 10, and needle-valve mechanism 20, operated b a float 21, controls the entry of liquid fue such as gasoline, into the float-chamber 19 by way of the pipe 22 the float thus maintaining a constant leve is? agproximately the dot-and-dash line Between the float-chamber and the casing 10 I provide two wells, a primary well 23 and an accelerating well 24, the relative positions being best shown in Figure 6. The

primary well 23 is connected with the floatchamber 19 by way of passageways 25 and 26, the latter passa eway being controlled by a needle-valve 2 which, at its u per end, screws into and hangs from an ad usting nut 28 which determines the maximum open position of the valve. This adjusting nut rests upon a sleeve 29, thru which the needle-valve stem ma slide, and the sleeve 29 rests upon an a justing nut 30, thru which the needle-valve stem may slide, this nut 30 threading into -an extension 31 of float-chamber 19. It ,will be seen that the" contact being shown in Figure 8. Figure 8- also illustrates'the pin 34, carried in the sleeve 29, which engages in a longitudinal slot 35 in the needle-valve stem 27, so as to prevent the needle-valve from turning when the screw 28 is turned for adjustment. The passageway 26 is never closed, but it will e seen that the adjustment of the nut 30 determines the lowermost position of the needle-valve and, thus, the minimum effec-' tive size of the passageway which it governs.

. From Figures 2 and 6 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 40 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 well 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 resently.

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 insertable in the casing 10 at a oint in proximity to the closed position 0 the sageway 42, and this connection is contro led by means of a' needle-valve 46 adjustable from the outside by means of the adjusting screw 47 a snapspring 48 being provide to hold this od ooanmsorow in position.

The annular passagewav39 connects with the atmosphere b way 49, the annu ar oove 50 around the Venturi tube 13, and t e air-port 51.

means of the passage- A secondary Venturi tube 52 is mounted in the main passageway in such a way that it terminates slightly above the most restricted portion of the main Venturi tube, and the most restricted portion of this secondary Venturi tube therefore lying considerably further down. This secondary Venturi tube is mounted in a spider 53, which spans the air-passage, as clearly shown in Figures 2 and 7, but leaves ample passage for air around it. Slightly above its most restricted portion this secondary Venturi tube is provided with an annular groove 54, from which fuel inlets or nozzles 55, 55 extend inwardly an'd radially, these nozzles being, preferably, distributed equi distantly upon the inner periphery. It will be seen that air is admissible to the nozzle by Way of the air ports 51, groove 50, passageway 39 and aperture 41; a nozzle of this nature, wherein air is admitted to 'it, is known as an air-bled nozzle. The annular groove 54 is connected with the primary well 23 by means of the passageway 56, it being noted that the fuel nozzles 55, 55 lie above the 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 5, 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. a

Mounted upon a pivot-pin 59' upon the outside of the casing is a bell-crank lever having three arms, 60, 61 and62. The arm 60 extends upwardly and at itsupiper end is provided with a roller 60 adapte to ride upon the surface 58. The arm 61 extends horizontally and has its ends bifurcated at 63, 63, to embrace the sleeve 29, hereinbefore referred to, below the shoulder 64 thereon.

It will now be seen that 'when the roller '60 rides upon the surface 58, which condition'exists on the higher speeds, the. arm 61 of the bell-crank lever will engage the under side of the shoulder 64 on the sleeve 29 to lift the needle-valve 27 and keep it in its uppermost osition. When the roller 60 dro s into t e de ression 59, as it will due to t e location 0 the center of gravity of the bell-crank lever and the spring of the needle-valve, itwill be clear that the needlevalve 27 will be allowed todescend to its lowermost position. Again, when the roller 60 rides upon the portion 58 of the cam, the needle-valve will be in its uppermost position.

The shaft 15 of the intake-valve 14 is provided with the rising cam 65, which is followed by a roller 66 on the arm 62 of the bell-crank lever. 'As illustrated in Figure '5, the shaft 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 temporary dash adjustment,. and 'under special conditions, the air maybe restricted 7 10 by the valve 14 and simultaneously the flow of gasoline intofthe primary well 23 may be maximum by reason of the lifting of the needles 271w the action of'the cam 65 regardless of the position of the throttle 16.

Theaccelerating well 24, whichhas hereinbefore been referred to, is fed directly from the float-chamber 19 by means of the restricted passageway 67 sh\ n in Figures 2 and 4. A tube 68, which depends from a screwplug69 threaded in the top of this well,'is placed concentrically in the well. the

interior of this tube being connected by in Figure 6. In this figure the dot-'and-dash means of ports 70 with an" annular groove 71 in the plug69; This annular groove 71, as illustrated in Figure 7. connects, by means of a small tube 72, with a fuel-nozzle 7 3 terminating within v the secondary 'Venturi 'tube 52 slightly above the fuel'nozzles 55, as illustrated in Figure 2 and alsovin Figure 7 This fuel-nozzle I refer to as the accelerating nozzle and I shall describe its operation presently.

- The tube .68 is provided with-a series of ports 74, arranged in vertical succession along the length of the tube, and, preferably, equidistantly spaced apart, as shown line indicates the fuel level in the float:

chamber, and, under ordinary conditions.

theuppermost of these apertures lies above this fuel-level. Openings 75, 7 5 permit the entry of air into the space surrounding the tube 68.

1 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 1 fuel de- 5 pends upon the position in which the throttle is maintained. when the engin' is cranked,

' but. it will sufiice as a general; statement-to say that gasoline goes to the engine from the nozzle 43 and also from the fuel nozzles 55. since, at starting, collected fuel stands in the passageways leading to these nozzles. there will be'a-desirable excess of fuelfto compensate for the coolness of the enginecylinders, the lag in response of the gasoline, since the-gasoline is heavier than air, and the excess of air.

Inassuming now a condition of idling or very low running, the throttle is closed as far as it can be, in which position, as shown in dotted line in Figure 2, the nozzle 43 may feed over the throttle.- Under these conditionsair entering the mainair-inlet passes upwardly thru the Venturi tubes and into the passageway 45, where it goesinto the passageway 42, mixing with the rising gasoline and goingon to the engine. It will be seen that the outlet of the nozzle 43 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 tothe engine with themixture which comes from the nozzle 43. Under these conditions the reduction in pressure below the throttleis so slight that no feed effect is had upon the jets in the secondary Venturi tube. The adjusting screw 4 1 the needle-valve 27 is in its uppermost position, giving a fullsupply of gasoline. If,

as for instance in colder weather. a somewhat richer mixture is desired under the circumstances, the dash-adjustment maybe manipulated to slightly close oif air in the main air-inlet 11.

If it now assumed that the throttle is gradually opened, it will be seen that the first elfect, which will be .of very short du' ration, however, will be a temporary restrict on 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 43, with a slight reduction in the amount of air passing thereby, thus slightly enriching the'mix .ture, in accordance with the slightly-advanced-position of the throttle.

As the throttleis opened wider, the suctionYat 43 decreases and the issue therefrom decreases correspondingly, but at the same time the suction is increased below the throttle and the nozzles '55, 55 come into play." It will remembered that up to this time the nozzles 55,have been practically inert, fornot only has there not been suflicient influence to ra se the level of the gasoline in the passageway'56 toward the nozzles 55, 55, but the level has actually i been lowered by the withdrawal of fuel thru the aperture '40 and upwardly thru the central passageway 38 vand tube 37. As the throttle is opened, however, and suction be comes efi'ective 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 nozzles 55, 55. Thus, as noz- -zle 43 gradually recedes in action with'the' opening movementof the, throttle, the nozzles 55,55 increase in action. I

It will be seen thatin 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 effective this fuel is drawn out and thereafter air, entering by way of the passageways 51, 50 and 49, bleeds into the gasoline supply to the nozzles 55, 55. This action is called compensation being for the purpose of compensating for the tendency of the mixture to grow richer as the suction increases.

During this description of the operation of the nozzles 55, 55, it is opportune to refer to the double venturi construction whereby the usual venturi effect is secured within the secondary venturi 52, while the primary venturi 13 has a similar super-effect upon the secondary Venturi tube as a nozzle.

By this means "the depression at the nozzles is multiplied in large proportions, it be ing noted that the secondary venturi terminates at the point of maximum depression in the primary venturi.

In the design of anycarburetor there are two essential requirements, which to a cer tain extent oppose one another ;to deliver amaximum charge of air .to the en ine, and to exert the maximum atomizing ei ect upon the fuel, which maximum atomizing effect is more or less a function of the suction or force 'by which the fuel is drawn from thenozzle. A strong suction on the nozzle usually. involves a high air velocity past it, and to obtain a high air velocity in an ordinary single Venturi carburetor generally in volves a considerable vacuum or depression in the intake manifold of the engine. This means that the air charge delivered to the -engine is rarefied and of less density than would be the case if the air velocity were less, thus preventing m'ximumair charge if the suction on the noz 1c is to be suflicient,

and if the single-venturi is made of such size as to operate properly at low air velocities it will not be adequate for the demand at high air velocities. By applicants arrangement only a small art of the air taken in by the motor is raised to high velocity, and the maximum charge of air is most efliciently secured on both low and high suctions simultaneously with a maximum suction upon the nozzle. This result is secured basically by the use of two Ven- -turi tubes, with the secondary venturi outlet disposed at the point of greatest depression in the large venturi, a most important point since improper relation of the tubes makes the desired action impossible; then improved by the radial nozzles, since an ax1a1 nozzle in such a small tube creates Leashes eddy currents, and the carbureting action as a whole being then further improved by air bleeding the nozzles. 1 This last-named point is important for this reason: It is an accepted fact that in-an ordinary uncompensated carburetor the mixture tends to grow richer as the suction increases. The

ouble venturi partly counteracts this tendency by reason of the easy passage of air only between the two venturis and the bleeding of air into the jet also partly counteracts this tendency, together counteracting it entirely or practically so. If either of these devices were designed to do all the compensating, their purposes would be defeated. If the bleed were made large enough to do so, the liquid fuel would go out in slugs, and if the outer venturi were made too large it would not produce the desired effect upon the inner one. Thus, these two devices, working together and in harmony, have been found to produce the desired result.

As an example of correct relative sizes it may be said that with an internal diameter of three-eighths of an inch for the most restricted part of the secondary venturi, an external diameter of nine-sixteenths of an inch for the upper cylindrical port on thereof andan internal diameter of fifteen-sixteenths of an inch for the most restricted part of the primary venturi are proper.

.The result is a thorough vaporization and a complete pick-up of the fuel fed from the jets, there being in each stage a Suficiently restricted passageway so as to maintain the desired reduction in pressure in order to take up all the fuel, whereas the total air passageway is sufficient for the demands of the engine. Since the jets 55 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, the effect is greatly multiplied over a single venturi construction.

During this period of intermediate running less fuel than the suction would draw is entirely sufficient 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 andI 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 needle-valve -27 may'drop to its lowermost position and ammo sageway by way of aperture 41, ashes been described, dis laces gasoline to a small extent tokeep own the supply. p A s hi her running takesjplace, however,

.the-nee e-Ivalve 27 ;must again bejraised -tew return to the position of maximum: power, and this, as has been" described isf provided for by the riding of the roller fififiupon the surface 58 of the cam 57, maintaining the needle-valve 27 in its uppermost positioIn throughout the remainder of the ran is important, however "in this connection, to point out that, as the 'ghersuctions are attained, more and more air is bled in thru the aperture 41 and proportionatel gasoline is displaced, so that, althoug more gasoline is necessary on the higher running, the provision of more in proportionwis' pile- ,vented and, as a matter of fact, over go anced, so as .to make'the mixture somewhat .leaner on the high speeds.

I I come now to a consideration of the ac- .celerating well. What I desire is ateinporary 'surcharging-of the with gaso line upon acceleration, that is, at-the iiingof a periodof increased suction. his

desirability follows from the natural inertia of the-fuel from the mainsource, and

the lag with which the feed of fuel, being heavier than air follows theiposition of the throttle; it is also due to the increased effort of the engine atthat particular time. It is obvious that this extra feed of gasoline should bemerely temporary, since, once the "as increased suction has become 'efiective 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 40 back thru the passageways 72, 71 and to the interior of the tube 68. This aoceleratwell does not feed onthe lower suctions for two reasons; first because the nozzle 73 is. at a higher planethan the main jets, and

-"also-becausethe uppermost apertures 74 in the tube 68 partlysatisfy the suction, and

it is not until this suction is not satisfied by the open apertures that gasoline responds.

In assuming amact of acceleration, it will so be clear that. an increase in suction willbe ,attended b an additional charge of gasoline from t eno'zzle 73, the size of this additional charge depending upon the amount or A 1 the increase, "This regulation of the charge 56". is'due': to the successive openings 74. For in stance}, when thesuction reaches a point whereit 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.

This uncovers-the second .bleeders, and, if

the two bleeders together satisfy the suc tion -which has thus been attained, no furth er gasoline will issue from the accelerating' well except that which is drawn out to n maintain the level where it has been brought. "In other words, then gasoline r flows out as fastasit flows in.. On the other hand, if these two bleeders 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 to iwhethermore gasoline is to go to the carbureting chamber-iswhether :or not the three bleeders, or three sets of bleeders, satisfy the suctlon.

It will also be clear that, if the increased range of suction is maintained, the level in the acceleratinglw'ell will be maintained at the point which was assumed when acceleration took place. Further acceleration to a still higher range chamber is whether or not the three bleeders, or three sets of bleeders, satisfy the suction. I a a n It-will also be clear that, if theincreased range of suction is maintained, the level. in the accelerating well. will be maintained at the point which was'fiassumed when acceleration took place. Further acceleration to a still higher range is merely a matter of further similar action, ashas been explained. If the suction is decreased, obviously the asoline will rise by gravity head from the oat-chamberto balance'the decreased suc-' tion, ,and a repeated acceleration means] the proper setting of the screw 28. The proper amount of gasoline for intermediate running is determined by the proper setting of the adjusting nut 30. The, ajustment for T e proper amount of gasoline for high speed is determined by idling is determined by the adjusting screw 46. Once determined for a particular engine, these adjustments need no attention ex-f cept for a marked change in climate or in the quality of the gasoline. As before stated, for temporary conditions, -such as startingin cold weather, the dash-adjustment is'utilizedto correct the action.

I claim:

In a carburetor, a constant level liquid fuel chamber, a' carbureting chamber .havinga mixture outlet, an air inlet and a fuel inlet,-said fuel inlet being open and above the level of liquid fuel in said constant level chamber and of constant size, a passageway leading from said constant level chamber to said fuel inlet, a valve in said passageway adapted to occupy a restricting position and a full flow position, a throttle in said mixture outlet, means for operating said valve 7:

by the movement of the throttle whereby memos tion when the throttle is in its intermediate moved to its closed position regardless of range and isdisposed in its full flow posithe position of the throttle. 10 tion when the throttle is nearly closed and in In witness whereof, I hereunto subscribe its ,high range, a choker valve in. said air my name this 6th day of August A. D. 1919.

inlet, and means operatively connecting said FRANK 6.1MOCK. first named valve and said choker valve Witnesses: whereby the former is disposed in its full BERTRAM WM. COLTMAN,

flow position when the choker valve is JULIUS MILLER.

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