US2750172A

US2750172A - Suction type carburetor

Info

Publication number: US2750172A
Application number: US253876A
Authority: US
Inventors: Milford D Burrows; Stanley Z Siwek; Goldberg Harry
Original assignee: Pioneer Gen E Motor Corp
Current assignee: Pioneer Gen E Motor Corp
Priority date: 1951-10-30
Filing date: 1951-10-30
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 BURROWS ETAL 2,750,172

SUCTION TYPE CARBURETOR 2 Sheets-Sheet 1 Filed Oct. 30, 1951 In wen 07's Jfi/fard .U. Burrows QSLQWZeg Z. 523067? jfarzy fiaider g' p m WA Jzzorzzeys June 12, 1956 M, D, BURROWS ET AL 2,750,172

SUCTION TYPE CARBURETOR IIIIII41 SUCTION TYPE CARBURETOR Milford D. Burrows, Stanley Z. Siwek, and Harry Goldberg, Chicago, Ill., assignors to Pioneer Gen-E-Motor Corporation, Chicago, Ill., a corporation of Delaware Application October 30, 1951, Serial No. 253,876

4 Claims. (Cl. 261-72) This invention relates to an improvement in suction type carburetors.

The invention has as one object to effect a mixing of fuel prior to the entry of the fuel into the induction passage.

Another object is to bring about an increase in power produced per unit of fuel used.

Another object is to increase the efliciency of the carburetor at the extremes of fuel level, and to stabilize the fuel-air ratio through the range of fuel levels.

Another object is to bring about a smoother transition than has previously existed in the change from the flow of fuel for idling to the flow of fuel for power.

Another object is to cool the carburetor by causing the incoming air to pass through an extensive metal passage before entering the injection chamber and thus to absorb heat from the carburetor.

Other objects will appear from time to time throughout the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a plan view of a carburetor embodying my invention in position upon a fuel tank, the path of the air therethrough being shown by arrows and with some parts shown in dotted lines.

Figure 2 is a side elevation of my invention similarly mounted and with parts broken away.

Figure 3 is a horizontal longitudinal section taken along line 3--3 of Figure 2.

Figure 4 is a side elevation showing in detail that side of the carburetor on which the flow of fuel and air is regulated.

Figure 5 is an enlarged section taken along line 55 of Figure 4.

Figure 6 is a sectional detail taken along line 66 of Figure 5.

Figure 7 is a section taken along line 77 of Figure 4, showing the butterfly valve in the full open position.

Figure 8 is a variant form shown in section showing the valve in the idling position.

Figure 9 is a section taken on line 9-9 of Figure 8.

1 indicates generally a suction type carburetor, shown in Figures 1 and 2 as being mounted in operative position upon a fuel tank 2. The carburetor 1 may be secured to the fuel tank 2 by means of a flange 3, a boss 4, and bolts 5 passing through said flange and said boss into bolt-receiving openings in the upper surface of the fuel tank 2 as at 7.

As shown in Figures 1 and 2, the flange 3 also extends beyond the upper surface of fuel tank 2 so that bolts 8 may pass through the flange as at 9 and secure to the body at that point a downwardly extending intake manifold 10, preferably provided with a filter 10a. The intake manifold 10, which could also be integral with the carburetor body if that form were desired, preferably and for reasons appearing later in the specification, joins the underside of the body at the remote or closed end 11 of an air passage 12. The air passage12 extends,-as shown nited States Patent 0 2,750,172 Patented June 12, 1956 most clearly in Figures 1 and 3, to an area designated generally as 13 which is adjacent the mouth 14 of an having at its lower end a projection 22 and slightly above its lower end a transverse slot 23. The projection 22 pivots in a hole 24 and is secured by a bolt. 25 which is in threaded engagement with a hole slightly above the hole 24. A washer 26 rests against that part of the lever 21 which defines the slot 23, and a spring 27 extends between the head of the bolt 25 and the washer 26. The tightness of the lever 21 against the side of the carburetor may thus be adjusted, and the lever 21 may be moved to and held at any position along the travel of bolt 25 in the slot 23. A wire 29 may be used to connect an extension 30 on the upper surface 28 of the valve 19 to the governor vane of the engine (not shown). A governor spring 29a may be used extending from a suitable securing point 29b on the wire 29 to the lever 21, for the purpose of securing the desired adjustment against accidental changes due to vibrations, etc. To provide stops for the control of valve rotation, any stationary or fixed member such as abutment 31 on the carburetor body 1 for use in conjunction with a stop 32 and the extension 30 on the valve surface, is satisfactory. A screw 33 threaded into the extension 30, as shown in Figures 1 and 4, may be used to adjust the idling position of the valve 19 by determining the point to which the abutment 31 will cause the extension 30 to be interrupted in its rotation. Vertical displacement of the valve is prevented by a retaining member 34, having a portion 35 which overlies the valve surface 28 and which is removably secured to the carburetor by the bolt 5 which passes through the boss 4 and is one of the bolts securing the carburetor to the fuel tank.

Fuel is introduced into the carburetor by means of fuel pipe 36 which extends downwardly into fuel tank 2 and which preferably has at its lower end a strainer element 37 and ball-check 38. As best illustrated in Figures 5 and 8, the fuel pipe introduces fuel into a fuel-receiving chamber 39, whence the fuel passes through a restricted opening 40 in separating member 41 into a fueland airmixing chamber 42. This form is a convenient form, since a plug 48 is easily applied and may be removed for inspection. An alternative would be simply to have the fuel pipe 36 lead directly to the member, such as 41, which contains the opening 40 that leads into the mixing chamber 42. This latter, or mixing chamber, communicates with the valve 19 and the induction passage 15 by an orifice 43 or preferably by

orifices

43 and 44, the smaller orifice 43 being for the admission of fuel into the induction chamber for idling, the larger orifice 44 for power.

In order to effect the introduction of air into the mixing chamber 42, we provide a bleed from air passage 12. Such a bleed is most conveniently provided by running a channel 45 along the flat inner or bottom surface of the carburetor bodysuch surface being generally designated as 46 and being on a plane with the under surface of the flange 3-from air passage 12 to a point from which a small air bleed hole 47 may easily be extended into the mixing chamber 42. This channel 45 is shown in dotted lines in the horizontal longitudinal section of Figure 3 and is shown in section in Figure 6. The location of the origin of the bleed hole 47 is shown in Figure 3; its course from channel 45 is shown in dotted lines in Figure 4; it is shown in section in Figure 6; and its point of entry into mixing chamber 42 is indicated in Figures and 6. Any suitable means, such as a removable plug 48 in threaded engagement with the inner walls of the housing portion 49, may be used to seal the fuel-receiving chamber 39.

, The carburetor assembly is secured to an engine cylinder 50 by means of a flange 51 provided at the outlet end of induction passage 15 'and through holes 52 through which bolts 53 may 'pass to engage the engine cylinder.

In the operation of the carburetor, fuel from the tank 2 is drawn upwardly through the fuel pipe 36, while air is sucked upwardly into the intake manifold 10. As stated previously, the air is preferably introduced by intake manifold 10 to the air passage 12 at the remote or closed end 11 thereof. Introduction of the air at this point accomplishes two desirable purposes. It provides for a long travel of air within the carburetor prior to the airs mixture with the fuel. This travel of the air through air passage 12 provides for cooling of the carburetor since the air in its course through the passage 12 will absorb heat given off to the carburetor from the engine. Secondly, the introduction of intake air at this point renders easy and convenient the bleeding off of a part thereof into channel 45 and air bleed hole 47 as previously discussed. It is, ofcourse, true that the air bleed could enter the mixing chamber 42 directly-from the atmosphere, or from any outside source, as through an orifice 47 (a) such as that shown in Figures 8 and 9. The only real disadvantage to introducing air by an orifice such as the direct atmosphere-to-mixing-chamber orifice 47(w) is that such air is unfiltered, or at least is not as conveniently filtered as is air taken in originally through a filtered intake, as 10 and 10(a). There is, however, no reason why, aside from impurities in the air, a direct orifice such as 47 (a) cannot be just as efiicient for fuel-air mixing purposes as can an air bleed taken'olf the main air passage 12.

Let it be assumed that the choke 16 is at least partially open. In that case the intake air, minus the small portion thereof which is bled off into the mixing chamber in the manner hereinbefore set forth, turns at portion 13 and enters induction passage 15. Let it also be assumed that the valve 19 is full open, or at least open past the power orifice 44 if both a power and a separate idling orifice are used. In such a case the air continues through the induction passage and on into the engine cylinder. While passing through the valve the air creates the suction which causes the fuel to be drawn through the orifice or orifices communicating between mixing chamber 42 and the induction passage 15. What we shall refer to as the bled air, which enters the mixing chamber 42 through a restricted opening, causes mixing of air and gas in the mixing chamber. As each droplet of fuel passes through the orifice 40 and into the mixing chamber 42, it is caught in turbulent air. The size of the units of fuel introduced through the orifice 40 is immediately reduced by this turbulence, and as the fuel continues to be introduced into this turbulent air within the mixing chamber, a vapor is formed with the result that no raw fuel, completely unmixed with air, drips into the valve 19 through

orifice

43 or 44.

Experience has shown that even in the absence of a mixing chamber such as is disclosed herein, some air space must be provided between the outlet orifice in what we have termed fuel-receiving chamber 39 and the orifice or orifices leading into the induction chamber. Otherwise there is too much surface tension to allow for an even How of fuel into the induction chamber. In all cases in which some air space at this point is present, if a needle valve or metering pin is used, some raw fuel will drip into such chamber or air space about the needle or pin and will in turn be drawn outinto the induction passage in excessively large drops. Similarly, when no such valve means of adjusting fuel flow into the preinduction air space is used, raw fuel is sucked through an orifice such as 40 and passes through and out of the non-turbulent air space unmixed. This difficulty and the attendant engine inefficiency are to a very great degree eliminated by the air bleed structure disclosed herein, which results in the formation of a passage of air which is constantly and rapidly moving through the mixing chamber and which enters that chamber from an angle different from the angle of entry of the fuel, and which thereby collides with the fuel and causes the fuel particles to be broken up while they are still within and passing through the mixing chamber.

The provision of the mixing chamber described herein has, in tests, demonstrated specific improvements in engine performance. When a suction type carburetor without an air bleed is adjusted for good performance and power output at a relatively high engine speed, then at lower engine speeds at no-load conditions, the fuel-air ratio is too rich for satisfactory performance. When the engine is adjusted for good idling, then at the higher engine speeds, the fuel-air ratio is too lean for satisfactory performance. The bleed hole leading into a fuel-air-mixing chamber between the fuel-receiving chamber and the orifices which discharge into the induction passage of the carburetor affects the flow of gasoline into the mixing chamber by converting the liquid gasoline to an atomized mixture. When the carburetor is adjusted for good performance at the higher engine speed the gasoline is mixed with air in the mixing chamber before being discharged through the orifices into the butterfly valve, The mixture of air and gasoline into the carburetor throat is thus atomized and made more homogeneous; and more economical and efiicient engine performance is achieved than is otherwise possible to effect.

Furthermore, in this type of carburetor, wherein fuel must be lifted before it can be used, the efliciency of the engine decreases as the fuel level lowers. This is true because as the fuel level lowers it becomes increasingly difficult to raise the smaller amount of fuel which is near the bottom of the fuel tank. Our invention does not increase the suction available and, therefore, does not cause any increased lifting, but it does cause a much better mixture of fuel and air than is possible without the air bleed, and thus each unit of fuel produces more power than it otherwise would. As a result, the loss of power which is noticeable when the fuel level is low in any suction type carburetor without our invention is to a great degree eliminated in the structure which we disclose and claim, wherein each particle of lifted fuel is broken up and mixed with air before it enters the induction passage.

Although we have shown an operative form of our invention, it will be recognized that many changes in the form, shape and arrangement of parts can be made without departing from the spirit of the invention, and our showing is, therefore, to be taken as, in a sense, diagrammatic.

We claim:

1. A fioatless suction type carburetor assembly wherein the fuel tank is below the induction passage, the induction passage being open at one end for communication with the intake port of an engine cylinder, and having an air inlet in communication with the outside air supply, said carburetor assembly including a housing portion defining a fuel and air mixing chamber adjacent said induction passage, a jet orifice opening from said fuel and air mixing chamber into said induction passage at a zone of reduced pressure, means for delivering fuel to said fuel and air mixing chamber including a depending fuel carrying conduit communicating through a restricted orifice with said fuel and air mixing chamber and extending downwardly into said fuel tank, and an air bleed passage extending from the outside air supply and through said housing portion and into said fuel and air mixing chamber, said air bleed passage being angularly arranged with respect to the axis of said restricted orifice to supply a stream of air to said chamber in a direction other than substantially parallel to the direction of entry of the fuel into said chamber.

2. A floatless suction type carburetor assembly wherein the fuel tank is below the induction passage, the in duction passage being open at one end for communication with the intake port of an engine cylinder, and having an air inlet in communication with the outside air supply, said assembly including a housing having a bore therein, said bore extending transversely to said induction passage and communicating through a jet orifice with said induction passage at a zone of reduced pressure, means dividing said bore into a fuel receiving chamber and a fuel and air mixing chamber, a restricted orifice allowing communication between said chambers, means for supplying fuel to said fuel receiving chamber comprising a depending fuel carrying conduit in communication with said fuel receiving chamber and extending downwardly into said fuel tank, said induction passage having contiguous portions providing a change in the direction of the flow of air through said induction passage from the point of connection with said air inlet, and an air bleed passage extending from said air inlet passage to said fuel and air mixing chamber, said air bleed passage being angularly arranged with respect to the axis of said restricted orifice.

3. The structure of claim 2 wherein said air bleed passage enters said fuel and air mixing chamber along an axis extending approximately at right angles to the direction of entry of fuel to said fuel and air mixing chamber.

4. The structure of claim 2 characterized by and including a housing portion having an internally threaded bore and an inner and an outer member spaced apart from each other and in threaded engagement with said bore, the inner member defining said fuel and air mixing chamber with the inner end of the bore, said inner member defining said fuel receiving chamber with said outer member and said bore.

References Cited in the file of this patent UNITED STATES PATENTS 1,707,229 Lloyd Apr. 2, 1929 2,024,419 Ball et al. Dec. 17, 1935 2,093,011 Grosz Sept. 14, 1937 2,127,444 Emerson Aug. 16, 1938 2,157,074 Ericson May 2, 1939 2,407,535 Carlson et al. Sept. 10, 1946 2,529,242 Brown et al. Nov. 7, 1950 2,590,217 Snyder et al. Mar. 25, 1952 2,618,474 Agar Nov. 18, 1952 2,627,852 Dittmer Feb. 10, 1953 2,635,861 Olson Apr. 21, 1953