US 2668698 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
1954 E. c. ROLLINS 2,668,698
CARBURETOR Filed Jan. 23, 1952 2 She'ets-Sheet 2 INVENTOR. [vii/v: 6 fuzz/m5 Patented Feb. 9, 1954 UNITED STATES OFFICE 8 Claims.
This invention relates to carburetors, and is particularly concerned with carburetors for internal combustion engines.
Throughout the history of the development of the internal combustion engine, the problems of carburetion whereby liquid fuel is mixed with the combustion supporting air have been of paramount importance. Numerous ingenious devices have been proposed for solving various of the problems; some deal with throttling as a means of controlling the amount of air and gas mixture supplied to the combustion chamber; others are directed to the control of the proportionate ratio of fuel to air; while a preponderance of the development work has been concerned with the intermingling of fuel and air in such manner as to deliver the resultant mixture in the most desirable form for rapid combustion. In most carburetors all three of these problems, together with others of less prominence, are dealt with collectively in an effort to produce a single instrumentality, where various elements combine to provide an improved overall eiiiciency and effectiveness.
The present invention provides a carburetor of this latter type, wherein the throttling means, together with air flow through the carburetor responding to variations in the throttle adjustment, acts to vary the proportion of fuel to air in a manner designed to meet the varying demands of the engine in a novel and improved manner. The present structure also provides novel and improved means for the delivery of fuel to the air stream to intimately combine therewith and develop a mixture of enhanced burning qualities. In the present invention these and other factors are dealt with collectively and in such manner as to provide improved efiiciency in each individual respect without sacrifice of efiiciency in a companion aspect of the total ro le It is, therefore, among the primary objects of the present invention to provide a novel and improved carburetor by Which fuel and air are intimately mixed and controlled as to proportion as well as to total delivery of the mixture to an engine.
iviore specifically, it is among the primary objects of the present invention to provide a novel and improved carburetor having a readily controllable and engine responsive fuel, and air mixing means whereby fuel is delivered to air in a finely divided or atomized state to be intimately mixed therewith.
A further specific object of the present invention is to provide a novel and improved carburetor having rotary jet means whereby fuel is sprayed into a moving air stream as a swirling film of atomized liquid.
Another object of the present invention is to provide a self-actuating rotary means for delivering fuel to the air stream of a carburetor.
It is also among the objects of the present invention to provide controllable engine responsive means selectively operable to elect one or a combination of fuel supply means for entraining liquid fuel in an air stream.
Numerous other objects'and features of the present invention will be apparent from the 'following specification when taken in conjunction with the accompanying drawings wherein:
Fig. 1 is a vertical, central section through one preferred form of the present invention.
Fig. 2 is an enlarged detail section through the rotor of Fig. 1.
Fig. 3 is a top plan view, looking into the air horn of the device of Figs. 1 and 2.
In general terms, the present invention may be defined as comprising a carburetor having a central air horn, an annular float-controlled fuel chamber surrounding the horn, and a central air-driven rotary fuel-delivering jet arrangement for delivering fuel in an atomized condition to the flowing air stream to be intimately combined therewith. The invention also embraces a novel and improved means for the delivery of fuel to the air in automatically varying proportions commensurate with the varying requirements of the engine as its speed and load increases and decreases. The invention also embraces means whereby fuel is admitted to the air stream independently of the rotary jet and means for supplying emergency additional increments of fuel for sudden acceleration. A throttling system is incorporated with the above features, the whole being so combined and related as to provide cooperation and interaction to the end that a sensitive and highly responsive carburetor is provided, having a maximum efiiciency over a broad range of operating conditions.
Referring more particularly to the drawings, the structure of the present invention comprises an upper housing member In and a lower housing member ll, jointly forming a central air passage I2 constituting an air horn and an annular surrounding fuel chamber 13. Below the lower housing member I I there is provided a throttle housing member 14, preferably spaced from the lower housing member II by a heat block l5. As indicated at [6 suitable gaskets are provided between the upperand lower housing members and on either side of the heat block I5. Suitable securing screws I! are provided for retaining the parts in assembled relation. Liquid fuel, such as gasoline, is supplied to the carburetor from a connection 20 under the control of a valve 2| actuated by a float 22 in such manner as to maintain a constant fuel level within the annular fuel chamber 3.
The air in float chamber I3 is maintained at a pressure slightly greater than the pressure in air horn |2 by means of impact tube 24, the small pressure difierential being commensurate with the velocity of the air passing through air horn.
|2. The upper end of impact tube 24 is disposed at a point lightly above the pivotal mounting 25 of choke valve 26 so that at all times such pressure is available over the fuel within the chamber I3. 7
From the chamber |3 liquid fuel is delivered through an orifice 3!! of a restrictor nipple 3| and thence through a valve body 32 to a passage 33 provided in an inwardly extending fin 34 formed in the throat portion 35 of the lower housing member Formed integrally with the upper housing member l and extending into the air horn in opposition to the fin 34 is a companion fin 36. The fins 34 and36 are provided with companion coaxial central bosses 31 and 38, respectively.
Between the bosses 31 and 38 there is mounted a jet rotor generally indicated at 39. Members 3'1 and 38 as well as their supporting fins 34 and 36 are spaced to receive the jet rotor 39 therebetween. The rotor 39 includes peripheral blades 40 extending outwardly therefrom to lie in the throat of the air horn, their outer edges being closely adjacent the walls of the horn. The blades 40 of the rotor are tilted to lie across the peripheral air passage formed between the rotor and the walls of the passage in such manner as to be driven by air passing through the horn, whereby the rotor will be revolved at a high speed, which speed is'commensurate with the rate of air flow through the carburetor. The central body 4| of the rotor is provided with radial passages 42 terminating in jet nozzles 43, the inner ends being provided with screens 44, in order to preclude plugging of the nozzles by foreign matter which may be carried by the fuel. The rotor body is mounted on a central axle 45 supported by upper and lower bearings 45 and 41. The lower bearing 41 is supported in a threaded bearing retainer 48 mounted within the boss 3'! of the fin 3 4. The upper bearing 46 is supported in a bearing member 49 carried by the boss 38 of the upper fin 35 and is biased toward the rotor 4! and against the shoulder of a threaded bearing pin by a coil spring 50, mounted on the pin and retained thereon by a nut 52. The axle 45 is provided with a central vertical bore 54 open at its upper end 55 for communication through a cooperating bore 56 in the bolt 5|. Bore 56 has transverse openings 51 registering with passages 58 and openings 59 into the throat of the air horn at. a point just above the blades of the jet rotor. The open lower end 55 of the axle 45 is in communication with a vertical passage 6| formed within the lower extension 62 of the bearing member 48.
Extension 62 is seated as indicated at 63 within. a a lower terminal well 64 at the inner end of the passage 33. Within the axle 45 there is provided a baffle 35, so arranged as to direct fuel entering from passage 33 and upwardly through the passage 6|, outwardly in the passages toward the nozzles 43. The bafile 65 is further arranged in the axle 45- so that it provides no restri tion to the passage of air to radial cross bores 42 from central bore 54, opening 55 and bores 56, 51, 58, and 5!! connecting with throat portion 35.
From the foregoing it will be seen that, when the engine is in operation to produce a suction through the air horn of the carburetor, air passing through the horn will impinge upon the blades 45 of the jet rotor to spin the rotor at high speed. The air passing through the throat portion 35 will also produce a suction at passage 59 leading to central axle bore 54 and opening 60 and thus cause fuel to be drawn through the restriction 30 of nipple 3|, past the valve 32 through passage 33, into well 64, and thence upwardly through the passage 6| of. the bearing member 48 and into the central passage 54 of the rotor 4| to be forcibly sprayed through the-jets 43. In this operation it will be noted that the suction exerted upon the fuel also causes air to be drawn upwardly with the fuel in passage 6| from vertically spaced aperture 56 in the wall of the extension 62 of the bearing 48, thus forming an air-bled jet restriction in passages 66 and 6|. This bleed air is drawn from float chamber 3, through restriction l2 and passage 70 located in boss 1| and thence through passage 59 which communicates with chamber 38, enlarged bore 67 surrounding bearing extension 62, and apertures 66. At low air velocities through the air horn fuel stands in well 6'! at a level which covers the lower apertures 55, but as the velocity and suction is increased the fuel in the well Bl is depressed, progressively opening the lower apertures to flow of bleed air and thusly providing additional restriction to the flow offuel through air-bled jet 5|. By this means the fuel air mixture ratio supplied by the carburetor is controlled in a manner suitable to the needs of the engine.
It will be further understood in the above operation that the capacity of the jet rotor 4| is at all times other than during cold chocking more than sufficient to deliver all fuel drawn to the radial cross bores of the rotor by the suction ex-'- erted on the fuel through passage 59 from throat portion 35. It will also be understood that any suction produced by the jet rotor on central duct 54 in excess of that produced at passage 59 will immediately cause air to be bled into the radial cross bores 42 from passage 54 and opening 55. This bleed air mixes with the fuel and air drawn upwardly through passage 6| and opening 60 and is pumped out into the throat portion 35 through jet nozzles 43, the bleed air having increased the volume to be pumped by the jet rotor until the suction of the pump is automatically in equilibrium with the suction exerted from passage 59. Thus, by the very nature of this pump bleed arrangement the excess capacity of the jet rotor cannot materially affect the quantity of fuel drawn to it and hence the fuel/air ratio delivered to the engine. This feature of the invention is of paramount importance inasmuch as rapid accelerations or decelerations of the air passing through the horn together with the inherent inertia of the jet rotor would have an undesirable affect upon the mixture ratio supplied to the engine as also would any change in rotor speed as compared to the air velocity through the carburetor as might be caused by variable bearing friction, etc.
The flow of fuel from the chamber H; to thepassage 33 is partially under automatic control by means of valve 15 and metering orifice IS in the valve body 32. Thevalve 15 is normally urged upward by a valve spring 16 surrounding its stem 1'1 and it may be urged from. its scat agamst tension of its spring 16 by anopposing spring l8 mounted upon an actuating rod 19 provided with a piston to seated within the chamber 813. The chamber 82! communicatesthrough a. duct H with an opening 83 located in the air passage below the throttle valve 84'. Thus at. high pressure difierentials the parts be in the position indicated in Figs. 1 and 2, and the valve 15 will be closed as in normal operation of themotor. At low engine; loads, as: for instance, when the throttle valve M is partially: closed, a. greater suction "is applied on the opening 83 and hence. through the port &2,- thus; maintaining the piston to with drawn in the chamber Bil. Howeven-when the throttle is opened a greater extenhwhereupon the. pressure: is relieved, the spring lilwill move the rod 19; downwardly, torch-1g the valve 1'5 from its seat against the tension of its spring; l6 so. as to permit in-flow of fuel around the. valve l5 through orifice H6; and into the passagethus increasing the rate of fuel supply in response to the pressure changes in the airpassage directly below the throttle 84,.
'Foridling operation, fuel may also, be admitted to the air passage both independently and coniunotionally with the admission of fuel throu h the: rotary jet depending upon the opening of throttle 84. For this purpose. there is provided a fuel passage 85 controlled by a threaded needle valve 86 and a spring 81 therefor, the opening 85 being just. below the. edge of the throttle when the. throttle is in closed position. There is also provided an opening 88 spaced slightly upwardly from the opening 35 and located just above the edge of the throttle when the throttle is in closed position. Both apertures 85 and 85 communicate by a duct 89 through the block I5 to a vertical duct 9c in the lower block H. The duct is provided with upper and lower restrlctors 9| and 92, respectively. Above the upper restrlctor Hi, the. duct is in communication with the restricted throat 93. of the carburetor and intermediate the. restrictors a branch port 94 leads to a fuel tube 95 which communicates with the passage 33. This arrangement is such that during idling speeds when the suction at the throttle is high as compared with the pressureatthe throat 93, fuel will be sucked up through the tube 95 and downwardly in the duct 90 to discharge from the ports 85 or 88. This idling phase of operation is such that the idling fuel drawn. through idle tube restriction 95 and through metering restriction 30 causes the fuel in passage 6.1 and central duct, 54 to be depressed below the level of radial cross'bores 42 and hence no fuel is delivered by the jet rotor 43. However, as the throttle is opened past the idle position the increased suction on the fuel in central duct 54 overcomes the depression caused by the idle fuel flow and fuel starts to deliver from the jet rotor, and for this intermediate phase of operation fuel is caused to flow from both the idle system and the main jet rotor system. At wider throttle posi l t even though the rotor may be rotating at speed.
when thaeugine: is to be accelerated as 'br'lull opening of the; throttle 824'. by actuation thereof through the .throttleroperatingi shaft um, a. jet oftuelmaybe sprayed. directly into the air. passag-e at a, point; adjacent the rotor by means-of a pump comprising a piston fill mountedupon a shaft; m2 and located within a pump well l;ll3-. The spring tilt; encircles-theshaft m to'hcld th piston normally in, upper position as. indicated and an actuating bracket Hi5 provided en a ing the. shall: 1 or and mounted on an. operating: rod b8!- audsccm'cdl asat l-Mto a 1:08 connected with thcthrottle shalt. tall... By this. arra gement, as the throttle. is opened, the rod H16 is: moved downwardly to move the piston I01; downwardly in the. piston chamber Hi3. Fuel is supplied to the chamber [83, from chamber l3. by a. duct. H0 and upwardly throu h a ball check valve 1H. When the piston. is depressedby actuation of the throttle, fuel passes; from, the chamber 183i outward'ly through a-duc-t H2, past a ball check valve H3 and to a metering jet H4 to impinge against. the blades all of the rotor. An impact tube Midis provided in the air passage of the carburetor and air is admitted .therethrough; to the. jet ell-ivicev 1M soas to mingle with the. fuel injected by the pump.
During choking of the carburetor for cold start,- ing of the engine, the choke valve 26 is rotated either manually or by automatic means to a completely closed position. in air horn |2 With the valve thus closed engine suction is exerted direct ly upon idling jets 8.5 and $8., jet rotor nozzles pass es-59.. and accelerating pump nozzle H4, causinga comparatively large volume of. fuel together with a small volume of air supplied through, choke. valve bleed opening 2'! to be supplied to. the engine. In this choking operation it is important to notethat the jet nozzles 4.3 are too restricted to supply sufficient. choking, fuel and. that such fuel. mustlbe. obtained from other openings; firstly, since insufficient airis. admit.- ted to rotate the jet rotor M it is possible for fuel to be delivered past the. block 65-, and thence through. passages 54 55,, 56, 51, 58 and 59 to the air passage 35, secondly, inasmuch as impact tube H5 is located upon the engine suction side of choke valve 26 it is possible for thisv suction to be fully exerted upon acceleratingnozzle I I4 and fuel is. supplied from air passage 35 b this nozzlc from float chamber 13,, through passage H0,
check valve Hl, chamber 103, passa e H2, and check valve H3. When the engine starts to. fire the choke valve is. partially opened permitting increased air flow through the air passage of the carburetor, thus causing rapid rotation of rotor M and terminating fuel delivery from passage 59. This increased air velocity also causes air to flow through impact tube. H5, thus re ucin the. suction on accelerating .jet H4. until no l isdclivered iromthis source other than. by action of pump 19!. 'Whcn the engine is fully warmed up the. choke. valve 26 is completely open and the carburetor functions as. described below.
In the normal operation of the device, it will be notedthat-with the throttle valve closed, fuel is admitted for idling speeds of the enginethrough the apertures and/or. .The former; being located below the edgeof. the throttle. will deliver fuel when the throttle. is. fully. closed while the upper apcrtureor port 88: deliver fuel for idling speeds when the throttle is parti lly opened. -When. thelthrottlc is further opened.
the increased suction at the jet rotor 4| causes fuel to be delivered from this jet in conjunction with the fuel delivered by the idle apertures 85 and 88 until at still wider throttle positions the suction in passage 33 exerted from throat portion 35 is greater than that available at the idle tube 95 and all fuel is delivered by the jet rotor and none by the idle system. At intermediate and moderately low speeds, beyond idling speed,
- suction in the carburetor acts through the port 83 and the duct 82, holding the piston 80 upwardly against the tension of the spring 18, thus maintaining the valve I5 closed and restricting the passage of fuel to the rotor to that entering by means of the restrictor 30. At all speeds, however, with the throttle wide or nearly wide open, pressure diminishes at the port 83 and thence the spring 18 will act to move the piston 89 downwardly to unseat the valve 75, permitting a greater flow of fuel to the rotor through the passage 33. As before noted, when the accelerator is operated to suddenly open the throttle 34, the
action will cause a downward motion of the pump Hll in such manner as to inject a spurt of gasoline through the jet I M against the rotors to be atomized by such impact and delivered as a temporary increase of fuel.
Throughout the operation of the engine above idling speeds, it will be seen that air passage will maintain a high rate of revolution of the jet rotor and, as the result of such rotation, fuel is thrown at high velocity outwardly by centrifugal force to be atomized by the jets 43 and to be intimately mingled with the air stream by virtue of such rapid injection and by virtue of the agitating effect by the blades of the rotor. Hence, in such operation an intimately mixed atomized fuel is delivered to the air stream to form a highly volatile mixture admirably suited for combustion in the engine cylinders. In view of the balancing of the air pressures by the various connections referred to, it will be seen that the carburetor is automatic throughout the entire range of its operation and provides fuel supply for idling, such supply being automatically terminated and substituted by a different type of supply when the engine operates at higher speeds. It will further be noted that by means of the valve 15, as the throttle is fully opened, the valve will open to deliver a richer mixture in response to higher engine loads.
In considering the present invention, it will, of course, be understood that the invention is not limited to the specific structural details here shown but that numerous changes, modifications and the full use of equivalents may be resorted to in the practice of the invention without departing from the spirit or scope thereof as set forth in the appended claims.
Having thus described my invention, what I claim and desire to obtain by Letters Patent is:
l. A carburetor comprising: an air, horn provided intermediate its ends with a Venturi constriction; a vaned air motor having a hollow central hub mounted within said Venturi constriction, the overall diameter of said air motor being substantially equal to the inner diameter of said Venturi constriction; and outwardly extending fuel jets mounted in said hollow central hub between the vanes of said motor. ,2. A carburetor comprising: an air horn provided intermediate'its ends with a Venturi con=- striction; a throttle valve mounted in said horn adjacent its outlet end; a constant level fuel chamber supported by said air horn; a vaned air motor mounted in said Venturi constriction 00- axially therewith, the outer diameter of said air motor being substantially equal to the inner diameter of said Venturi constriction; radially extending fuel jets carried by said air motor; and means for establishing communication between said fuel chamber and said fuel jets whereby fuel delivered to said jets is discharged into said air horn.
3. A carburetor comprising: an air horn provided intermediate its ends with a Venturi constriction; a throttle valve mounted in said horn adjacent its outlet end; a constant level fuel chamber supported by said air horn; a vaned air motor mounted in said Venturi constriction coaxially therewith, the outer diameter of said air motor being substantially equal to the inner diameter of said Venturi constriction; radially extending fuel jets carried by said air motor; and means for delivering fuel from said fuel chamber to said fuel jets, said means being responsive t the fiow of air through said air horn.
4. A carburetor comprising: an air horn pro vided intermediate its ends with a Venturi constriction; a vaned air motor having a hollow cen tral hub mounted within said Venturi constriction, the overall diameter of said air motor being substantially equal to the inner diameter of said Venturi constriction; and a fuel conduit leading from said fuel chamber to said fuel jets; said conduit containing a fuel restriction effective during engine part loads and a valve controlled fuel restriction effective during engine full loads, said valve being responsive to a decrease in suction in said air horn at a point rearwardly of said throttle valve, whereby said part load restriction and said full load restriction conjointly act to control the flow of fuel from said fuel chamber to said fuel jets for engine full load operation.
5. A carburetor comprising: an air horn provided intermediate its ends with a Venturi constriction; a constant level fuel chamber mounted on said air horn; a vaned air motor mounted in said Venturi constriction, the outer diameter of said motor being substantially equal to the inner diameter of said Venturi constriction; a fuel centrifuge carried by said motor; and means for delivering fuel from said fuel chamber to said centrifuge.
6. A carburetor comprising: an air horn provided intermediate its ends with a Venturi constriction; an air motor mounted in said air horn adjacent said Venturi constriction; a fuel centrifuge carried by said motor for discharging fuel 4 into said horn; a constant level fuel chamber mounted on said air horn; means for delivering fuel from said fuel chamber to said fuel centrifuge; and means for establishing communication between the interior of said fuel centrifuge and a point within the air intake of said air horn.
'7. A carburetor comprising: an air horn formed intermediate its ends with a Venturi constriction; an air motor driven fuel centrifuge mounted within said Venturi constriction; a constant level fuel chamber mounted on said air horn opposite said Venturi constriction; a conduit communicating between said fuel chamber and the one end of said centrifuge and an air duct communicating between the intake side of said air horn and the opposite end of said centrifuge, said air duct, centrifuge and conduit being under the influence of the suction within the intake end of said air horn.
8. A carburetor comprising: an air horn provided intermediate its ends with a Venturi con-' striction; a throttle valve mounted in said horn adjacent its outlet end; a constant level fuel chamber supported by said air horn; a vaned air motor mounted in said Venturi constriction co axially therewith, the outer diameter of said air motor being substantially equal to the inner diameter of said Venturi constriction; radially extending fuel jets carried by said air motor; a fuel conduit leading from said fuel chamber to said fuel jets, said conduit containing a fuel restriction and an air bled fuel retriction serially acting to control the flow of fuel from said fuel chamber to said fuel jets in response to the passage to air through said air horn.
EUGENE C. ROLLINS.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Hippel Sept. 7, 1915 McClelland Apr. 13, 1926 Henkle Aug. 24, 1926 Skaer Aug. 20, 1929 Haddock Jan. 9, 1940 Ericson Mar. 30, 1943 Jones May 7, 1946 FOREIGN PATENTS Country Date Great Britain July 8, 1920