US2506812A - Carburetor - Google Patents

Description

M y 1950 A. c. RUSSELL 2,506,812

CARBURETOR Filed Aug. 21, 1946 2 Sheets-Sheet 2 Patented May 9, 1950 UNITED STATES PATENT OFFICE Okla. ApplicationfzfiftiZtfjj No. 691,944

This invention relates to devices for use with internal combustion engines using a liquid fuel, for converting the liquid into a mist or vapor and for mixing the vapor with air in such proportions that the mixture will burn instantly when introduced to the cylinders of the engine.

The primary aim of this invention is to provide a carburetor that will mix the fuel with air under wide variations of engine speed and power; that will vaporize the mixture under all differences in temperature; that will respond immediately to a demand for greater or less speed; and that will operate efiiciently in all such respects in spite of variations in the quality of the fuel used.

One of the most important aims of this inven tion is to provide a carburetor in the nature of that disclosed in my previously issued U. S. Let- 2 herent in the engine; and the means of column-- ing the novel features of my previously disclosed devices with the improved heating structure-of my present invention.

Other aims will be made clear or become apparent during the course of the followingspecificaltioninreferring to the accompanying drawing w ere Fig. 1 is a top plan view of a carburetor made in accordance with my present invention.

Fig. 2 is a side elevational view thereof. Fig. 3 is a fragmentary sectional view taken on line III-III of Fig. 1.

ters Patent No. 2,366,056, dated December 26,

1944, but which improves on said carburetors to the extent of being appreciably more efficient, considerably less complicated and expensive to manufacture and maintain in working condition,

and capable of presenting a unit that is less bulky,

lighter in weight, and more positive in its operation in response to the requirements of the engine with which it is used.

An important aim of this invention is to provide a carburetor having means for introducing a continuous charge of heatedair to the series of passages for directing air toward the surface of the raw fuel in the mixing chamber thereof which air is in addition to the final means of combining air with the fuel mixture and supplants the compartment for heated fluid usually provided to heat the mixture prior to its passage into the engine, and thereby insuring complete carburation and causing perfect combustion within the cylinders of the engine.

A further aim of this invention is to provide a carburetor having means for introducing heated air emanating from the exhaust manifold of the engine to the surface of the fuel within'the mixing chamber for causing carburation immediately conduit It in communication with the air,out1c't,

passage i4, forming a compartment for final mix- Fig. 4 is a vertical fragmentary sectional view taken online IV-IV of Fig.1;and

Fig. 5 is an enlarged; fragmentary, detailed.

cross-sectional view taken through the mixing chamber of the carburetor per se.

A sectional casing "I, when assembled presen an air intake l2, an air outlet passage l4, and a ing prior to introduction of the mixture into the engine with which the carburetor is used. A pipe It leads from this passage H to the intake manifold of theinternal combustion engine, not herein shown.

A butterfly valve is disposed within the pipe I, and although not illustrated, it may take any 'of the conventional forms and is mounted upon an axle 22 extending exteriorly to a connection with an operating lever 24. This lever 24 is joined to a throttle accessible to the operator whereby the speed of the engine is controlled by opening and closing the butterfly 'valve. A butterfly valve 2. in passage l2 controls the amount of air entering the carburetor therethrough.

A bowl 28 forms a part of the casing 10 and receives raw 'fuel from a.-fuel pipe, not shown, inserted in opening 30. An excessive flow of fuel into the bowl 28 is prevented by a float 32 that rises to close a valve 83 as fuel reaches predetermined point in thebowl 28.

A chambered mounting :4 within the bowl as is secured to the underside of the casing "that supports the bowl 28 and a plate 36 closes the bottom thereof as is clear in Figs. 3 and 4. A series of holes 38 in the side wall of the mounting 34 place the interior of this chambered mounting into direct communication with the bowl ll.

- A fitting Ill, having an opening 42 for a conduit 44, is held in place by the mounting 34 when the carburetor is assembled. This fitting 40 is thimble-like in form and has a shouldered flange at its rim to lie between a shoulder 46 on the mounting l4 and a part of the casing III.

A nonle member 66 projects into the fitting 46 and its central bore receives the lower end of the conduit 44. This nozzle member 66 is held in place within the mounting 64 by machine screws 62 and a number of downwardly and inwardly inclined air passages 54 formed in the nozzle member 66 converge toward the axis of the air outlet passage l4 and the nozzle member 56.

It is clear therefore, as seen in Fig. 4, that the passages 64 within the nozzle member 50 place a mixing chamber 56 within nozzle 50 into communioation with the outer extremities of the male 60. The fitting 40 shrouds the nozzle member 66 to form a closed space 58 therearound which in turn receives heated air from a tubular member or pipe 60 that is fitted into an intake port 62 formed in the side wall of the fitting 46. This pipe 60 leads to any suitable source of heated air, and is preferably in communication with the exhaust manifold (not shown) of the engine with which the carburetor is used for receiving exhaust gases therefrom, and is insulated as shown to maintain the air within the pipe 60 in a heated condition until it reaches the space 58.

The mixing chamber 56 within the nozzle 56 is joined to a lower portion of the chamber in the mounting 24 through a plug 64, having a valve 66 reciprocably and freely movable therein. This valve is,a tapered, pin-like member having a serrated head 66, and longitudinal movement of the valve 66 will feed a greater or lesser amount of fuel from the lower portion of the chamber in the mounting 34, into the mixing chamber 56.

An annular internal shoulder 16 On the nozsle member 56 is at the zone of juncture between the upper and lower portions of the mixing chamber 56. The portion of the mixing chamber 66 below this shoulder 10 is slightly greater in diameter than the portion of the mixing chamber 66 above the shoulder III.

This shoulder 16 lies directly beneath the inner ends of the air passages 54, and when heated air entering through the air passages 50 impinges upon the upper surface of the shoulder 76, a turbulence is established and the upward suction on the surface of the fuel in the mixing chamber 66, insures an entrainment of fuel particles within the heated air streaming inthrough the passages 64 and thence upwardly through the conduit l4.

The maximum movement of the valve 66 is inlever 62 with any manually manipulable instrumentality. A plunger 66 in engagement with a lateral extension 66 of the lever 62, is spring loaded and yieldably maintains the lever 62 in a position where the collar 12 (Fig. 4) is in a normal position.

A bracket cooperates with the collar 12 when choking oi' the carburetor is desired. This bracket comprises a pair of rods 66, a bridging member 62, supporting the valve 66 and an annular head or valve 64 formed to receive the annular lip of the collar 12 in creating a substantially air-tight joint.

The air outlet passage l4 of the casing II has an internal flange 66 with a diameter slightly less than the outside diameter of the valve head 64. Valve 64 is easily shifted along the internal flange 66. during the normal operation of the apparatus.

A spring loaded pin 66 extends through an opening provided in the casing i0, and the head of this pin lies against a cam face I66 on the lever 62. The function of these parts will be hereinafter definitely set forth.

Assuming the parts of the carburetor illustrated and above described to be in the position shown in the drawings, particularly Fig. 4:

The engine may be started with a rich mixture by moving the lever 62 to turn the shaft 66 and sufficient to force the head 68 against the under surface of the portion of the nozzle 50 forming the shoulder 16, unless upward suction assists the structure hereinatfer described and which is employed for motivating the valve 66. If, however, the valve 66 should be drawn upwardly into the mixing chamber 56, it will not escape because of the annular internal flange or head just dscribed. Likewise, if the head 66 of the valve 66 should strike the inside of the nozzle member 56, it will not block the movement of fuel.

A collar 12, slidable upon the fitting 46, has a pair of diametrically opposed stubs 14 to receive a yoke 16, and a notch 18 extending upwardly from the lower edge thereof provides clearance for the tubular member 66 as the collar 12 slides on the fitting 46 through the action of the yoke 16. This yoke 16 is mounted upon a shaft 66 through the casing l6 and to a point exteriorly thereof where a choke lever 62 is afllxed thereto.

A suitable fitting 64 is employed to join the thereby elevate the collar I2, valve head 64, members 66 and 62 of the bracket, and manifestly, the valve 66 to allow the mixing chamber 56 to flll with fuel. Suction created in the engine will draw this fuel mixture out through conduit l4 and thence to the cylinders of the engine through the pipe l6 and the intake manifold, not here illustrated. No air will enter the pipe ill from the air inlet l2, but as soon as the engine is started, the lever 62 will be returned to the normal position, shown in Fig. 2, to allow automatic operation.

When the lever 62 is moved, the cam I60 will force the pin 66 inwardly and into the path of travel of the valve head 94. Thus, a positive stop is established for the entire bracket, of which annular valve 64 is a part and no air can be drawn from the intake i2 because of the complete sealing-off of the air inlet i2 from the air outlet 14 by the internal flange 96, annular valve 64, and the collar 12. when the choke is released, however, the spring on the pin 66 will return the pin to the position shown in Fig. 4, and thereafter the entire bracket may reciprocafe in response to suction and flow of air from the intake l2 to the outlet l4, and thence, the pipe l6.

As the engine runs, the valve 64 is lifted from the collar 12, and air passes into the mixing conduit I6, there to meet and mingle with the fuel and heated air mixture leaving the conduit i4. As the valve 64 is lifted in response to a greater flow of air, the valve pin 66 will be forced upwardly and thereby allow a greater amount of fuel to enter the mixing chamber 56 from within the lower chambered portion of the mounting 64.

As liquid fuel flows from within the lower portion of the mounting 24, the supply is replenished confines of the flange 96, air floods in to the outlet passage l4 from the inlet l2, past both the inner and outer annular edges of the valve 94. Thus, as soon as the valve 94 passes the flange 36, the amount of air will suddenly and appreciably increase.

So contouring the inner face of the casing I. along which the valve head 94 passesjprevents the possibility of binding or sticking and the rigid journaling of the rods 90 as shown, will further contribute to the ease of operation.

The flow of fuel into the bowl 28 will have no effect upon the bracket because its member 92 is confined within the mounting 34 where a quiescent condition prevails insofar as the fuel is concerned.

Manifestly, the actuation of the butterfly valve within the pipe l8 by actuating the shaft 22, will draw a greater or lesser amount of air through the carburetor and as soon as this air all traverses the mixing conduit IS, the fuel mixture emanating from the conduit 44 will never fail to mingle therewith.

Gases entering the space 58 from the exhaust manifold of the engine through the pipe 50 will move through the air passages 54 to be charged with fuel within the mixing chamber 56. There are preferably a number of these passages 54, and as indicated in my prior patent,the cross-sectional area of the conduit 44 is substantially the same as the combined cross-sectional areas of the passages 54.

It is clear from the foregoing that a continuous flow of heated air is introduced along the surface of the raw fuel within the mixing chamber 56, and as suction from the engine is created in the conduit 44, this heated air will be drawn from the pipe 60 and fuel will be moved from the chamber within the fitting 34 where complete carburation takes place in the mixing chamber 56 prior to movement of the mixture upwardly in conduit 44. It is well known by those skilled in the art that air and fluid can be more effectively combined if the air is preheated, and therefore, the fuel that emanates from the top of conduit 44 is not only entirely saturated with air, but this mixture is already heated as its passes into air flowing through casing l0 from air inlet I! to air outlet I 6. This insures that the final carburation will be complete before the mixture passes' into the conduit l8 and thence to the engine.

These improvements not only eliminate the bulky and undesirable jacket that encased the pipe l8 for. heating the mixture as disclosed in my prior patent, but makes for instant and effective combustion of the mixture in the engine since carburation is not as complete when heating of the mixture occurs after the air and fuel have been brought together.

This feature is particularly important in its function when choking occurs in the manner as set forth above. Since a rich mixture is desired for starting the engine, the air entering the inclined passages 54 will more effectively mix with fuel because of its preheating. than in my former patent wherein such air originated in the inlet passage l2.

Obviously the total air requirement of the engine should be greater than the total volume of air or gas that is permitted to flow through the pipe 60 so that the automatic opening of the valve head 12 will occur as above set down, and the size of the pipe 35 be determined accordingly.

0 Since a small amount of pressure will be present in the pipe 60, heated airwill to a large extent be present in the space 58 at all times, thereby reducing the required amount of suction from the intake manifold that would otherwise be necessary, to draw this air or gas through the pipe 60.

It may be found in some instances that certain types of engines will create more pressure in the exhaust manifolds thereof than in other engines, thereby introducing all the air requirement of the engine at the space 58. Such condition would tend to effect the automatic operation of the bracket and its valve head 94 to the extent of not being actuated by suction of air from the air inlet passage l2. Therefore, a control valve I02, having an actuating lever I 04, leading to a convenient point of access by the operator, is provided to vary the size of the opening through the pipe '60. This valve I02 is of the conventional type, mounted on the pipe 60 and having means within the pipe 60 to open and close the passage therethrough whereby the total volume of air passing into the space 58 can be kept below the total air requirement of the engine.

All of the aims and objects set forth at the outset in this specification are therefore made possible through the employment of a carburetor made in accordance with the above description and as shown in the accompanying drawings. It is obvious also that my present carburetor will operate in strict accordance with the principles set forth in U. S. Letters Patent No. 2,366,056, but with greater efliciency due to the improved arrangement of parts as herein set forth.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

In a carburetor having a hollow casing provided with a primary air intake port, an outlet, a bowl for fuel to be mixed with air, and a tubular member having a mixing chamber therein disposed to receive fuel from said bowl and to convey fuel and air mixture toward said outlet into the flow of air through the casing from said primary air inlet to said outlet, the improvement of which comprises the combination of a body surrounding a portion of said tubular member adjacent the mixing chamber thereof, presenting an air flow equalizing compartment separate from the flow of primary air through the casing; a valved conduit communicating at one end thereof with said compartment for directing secondary heated air to said compartment, said tubular member having a plurality of passages therein for placing said compartment into communication with said mixing chamber and disposed to direct heated air from the compartment toward the level of fuel in said mixing chamber.

-ANDREW CRAIG RUSSELL.

' REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,319,633 Waite Oct. 21, 1919 1,448,072 Little Mar. 13, 1923 1,700,863 Titman Feb. 5, 1929' 1,722,934 Medley July 30, 1929 2,114,548 Stadlman Apr. 19, 1938 2,118,038 Brodersonf et al May 24, 1938 3,366,056 Russell Dec. 26, 19M

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