US2899184A - Carburetor fuel nozzle construction - Google Patents

Description

Aug. l1, 1959 E. oLsoN cARBUREToR FUEL NozzLE CONSTRUCTION Filed Aug. 1, 1957 wir IN VEN TOR. P9/vez a/z riz-'P ATTORNEY ite States Patent CARBURETOR FUEL NOZZLE CONSTRUCTION Elmer Olson, Rochester, N.Y., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August f1, 1957, Serial No. 675,721

Claims. (Cl. 261-41) The present invention relates to a charge forming device for an internal combustion engine and more particularly a fuel cluster assembly therefor.

In a carburetor utilizing an air actuated throttle anteriorly of a mechanically actuated secondary throttle the flow of fuel is undesirably delayed by the introduction of fuel into the induction passage at a point anteriorly of the air actuated throttle. A carburetor of this type is shown in copending application Serial No. 257,578, Braun, filed November 2l, 1951, now abandoned. In the previous type of fuel supply systems as illustrated in the aforenoted application, when the pressure differential across the air actuated throttle reaches a suiciently high value to begin opening said throttle the flow of fuel through the secondary nozzle and cluster is delayed due to the initially small air ow through the fuel booster venturi. As a result of the fuel ow delay the fuel-air mixture is momentarily leaned out with a consequent fall-olf in engine power output.

lt is the purpose of the present invention to provide a novel fuel cluster arrangement in which the fuel supplied to the induction passage is more closely responsive to engine demand as reflected by the opening movement of the air actuated throttle. In the present device a fuel cluster arrangement is provided which insures that manifold vacuum will act on the fuel nozzle to insure immediate fuel ow as the air actuated throttle opens.

More specifically it is an object of the present invention to provide an air tube or cluster disposed in the induction passage and which tube is in communication with the fuel nozzle and further which tube is adapted to project into the induction passage space between a mechanical and an air actuated throttle to insure that said tube is exposed to manifold vacuum at any time the mechanical throttle is open.

The details of the present invention as well as other objects and advantages are set forth in the description which follows.

In the drawing:

Figure l shows a partially sectioned carburetor embodying the present invention;

Figure 2 represents a modified form of the present invention; and

Figure 3 illustrates an air actuated throttle adapted for use with the present invention.

A carburetor is shown generally at 10 and, except as will be hereinafter specifically pointed out, is adapted to function in substantially the same manner as the aforenoted Braun carburetor. The present carburetor will be described only in sufficient detail to provide a proper understanding of the operation of the instant invention.

A primary induction passage is shown at 12 and includes a throttle valve 14 disposed therein. A choke valve 16 is likewise disposed in the primary induction passage. A secondary induction passage 18 includes a throttle valve 20 and an air ow actuated throttle 21 anteriorly thereof. The throttles 14 and 20 are coupled for mechanical operation and cooperate in the manner set forth in the copending Braun application.

,In Figure 1 a fuel cluster is shown generally at 22 and includes a secondary or fuel booster venturi 24, an air passage 26 communicating at one end with the venturi 24 and having an atmospheric opening 28 at its other end. A secondary fuel nozzle 3) is supported from the fuel cluster 22 and extends within the secondary fuel well 32. Under high power output conditions, e.g. the secondary throttles 20 and 21 open, the air ilow through the secondary or booster venturi 24 will draw air across the beveled edge 34 of the secondary fuel nozzle 30 projecting within the air passage 26 thereby aspirating fuel into the secondary induction passage 18.

When the pressure differential across the unbalanced throttle 21 just reaches a value sufficient to begin opening the secondary throttle, however, there is insuiicient air ow through the booster venturi 24 to insure adequate fuel flow into the induction passage 18. As a result the combustible charge is inappropriately leaned out. To correct this situation, a tube 35 is disposed within induction passage 18 and is dependingly supported from the fuel cluster 22. Tube 34 communicates with the air passage 26 intermediate the atmospheric opening 28 and the booster venturi 24. The other end of the tube 34 projects through an opening 36 formed in the air actuated throttle 21 and terminates posteriorly of the throttle when the latter is in a closed position. in this way as the mechanically operated secondary throttle 20 opens the lower end of tube 34 will be exposed to manifold vacuum insuring immediate fuel iiow through the secondary fuel cluster 22 as soon as the air actuated throttle 21 begins to open. Accordingly, the leaning of the fuel-air mixture previously experienced during the initial opening of the air actuated throttle is avoided in the present device. As soon as the air ow past the air actuated throttle 21 reaches a suiciently high value the secondary venturi 24 will begin to function in the normal manner to supply the requisite quantities of fuel to the induction passage 1S.

As seen in Figure 3, the secondary air actuated throttle 21 is suitably slotted at 36 to permit the tube 34 to project therethrough. In order not to interfere with the air flow actuation of throttle 21 the slot or opening 36 is formed in the smaller area portion of the throttle in relation to the throttle shaft axis.

A modified form of the invention is shown in Figure 2 in which a different type of fuel cluster 40 is provided. In this modification the secondary or booster venturi is eliminated and in its stead the fuel cluster is formed With a straight tube 42 extending from above the secondary fuel Well 44 to below the air actuated throttle 46 through a slot 47 therein. ln this case secondary fuel nozzle 48 is provided having a bent portion 50 which extends into the tube 42 such that the beveled end 52 of the nozzle is exposed directly to the air ow through the secondary induction passage 54. As in the modification of Figure 1 with the air actuated throttle 46 closed and the posterior mechanical throttle partially open, manifold vacuum will at all times be active on the fuel nozzle through tube 42 Ito insure immediate fuel flow upon the opening of the air actuated throttle.

In order to more effectively tailor the fuel How through tube 35, an orifice 6ft is provided in passage 26 intermediate the tube and booster venturi 24. In this Way the resultant manifold vacuum force drawing air through passage opening 28 will be greater since the bleed of atmospheric air from the induction passage end of passage 26 Will be limited by the size of orifice 60. Thus by selecting the appropriate size of oriiice 60, the quantity of fuel flow through tube 35 may be established at a rate compatable with the desired operating characteristics of a particular engine. It is, of course, apparent that the use oforice 60 will vary the respective percentages of fuel ow through booster venturi 24 as well as through tube 35. Again the desired fuel flow relationships between venturi 24 and tube 35 will be determined, at least pa'rt, by the engineoperating characteristics desired.

It is apparent that various additional structural modifications may be made in the subject fuel cluster construction within the scope of the present invention, and that forms shown are merely for illustrative purposes.

I claim:

l. A charge forming device for an internal combustion engine comprising an induction passage including a mechanically actuated throttle valve, an air flow responsive throttle valve disposed in said induction passage anteriorly of said mechanically actuated throttle, a fuel well,.first tube means projecting within said fuel well and extending within said` induction passage anteriorly of said air ow responsive throttle for supplying fuel to said induction passage in response to air ow through said passage, and second tube means disposed in said induction passage and communicating proximate one end with said first tube means, the other end of said second tube means extending within .the space between said throttles.

2L A charge forming device for an internal combustion engine comprising an induction passage including a mechanically actuated throttle valve, an air flow responsive throttle valve mounted on a shaft and disposed in said induction passage anteriorly of said mechanically actuated throttle, a slot formed in said ow responsive throttle substantially normally to the shaft axis, a fuel well, first tube means projecting within said fuel well and extending within said induction passage anteriorly of said air ow responsive throttle for supplying fuel to said induction passage in response to air flow through said passage, and second tube means disposed in said induction passage and communicating proximate one end with said first tube means, the other end of said second tube means extending through said slot and into the space between said throttles.

3. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a choke valve in said passage anteriorly of said throttle valve, a second induction passage, a mechanically actuated throttle disposed in said secondary induction passage, an unbalanced lthrottle valve disposed in said secondary induction passage anteriorly of said mechanical throttle, a fuel well, a fuel nozzle projecting within said fuel well, an air passage communicating with said fuel nozzle and projecting within said secondary induction passage anteriorly of said unbalanced throttle, said air passage and fuel nozzle being adapted to supply fuel to the secondary induction passage in response to the air ow past said unbalanced throttle, a tube disposed within said secondary induction passage and communicating at one end with said air passage, said tube extending longitudinally of said secondary induction passage and terminating at its other end posteriorly of said unbalanced throttle when the latter is closed, engine manifold vacuum being adapted to act on said tube whenever said mechanically operated throttle is at least partially open.

4. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a choke valve in said passage anteriorly of said throttle valve, a secondary induction passage, a mechanically actuated throttle disposed in said secondary induction passage, an unbalanced area flow responsive throttle valve disposed in said secondary induction passage anteriorly of said mechanical throttle, a slot formed in the smallest area portion of the flow responsive throttle, a fuel well, a fuel nozzle projecting within said fuel well, an air passage communicating with said fuel nozzle and projecting within said secondary induction passage anteriorly of said unbalanced throttle, said air passage and fuel nozzle being adapted to supply fuel to the. secondary induction passage in response .to the air tlow past said unbalanced throttle, a tube disposed within said secondary induction passage and communicating at one end with said air passage, said tube extending longitudinally of said secondary induction passage and extending through said throttle slot to terminate at its other end posteriorly of said unbalanced throttle when the latter is closed, engine manifold vacuum being adapted to act on said tube whenever said mechanically operated throttle is at least partially open.

5. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary inductionpassage, a mechanically operated throttle in said rsecondary passage, an air flow responsive throttle disposed in said secondary passage anteriorly ofsaid mechanically operated throttle, a fuel well, a fuel nozzle projecting within said fuel well, a venturi disposed in said induction passage anteriorly of said air flow responsive throttle, an air passage communieating said venturi and said nozzle whereby air flow through said venturi will cause fuel to flow through said air passage and into said induction passage in proportion to the velocity of said air ow, a tube disposed within said induction passage and communicating at one end with said air passage intermediate said venturi and said fuel nozzle, the other end of said tube extending into the space between said secondary induction passage throttles.

6. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary induction passage, a mechanically operated throttle in said secondary passage, an air ow responsive throttle disposed in said secondary passage anteriorly of said mechanically operated throttle, a slot formed in said tlow responsive throttle, a fuel well, aifuel nozzle projecting within said fuel well, a booster venturivdisposed in said induction passage anteriorly of said airflow responsive throttle, an air passage extending transversely of said induction passage and communicating said venturi and said nozzle whereby air ow through said venturi will cause fuel to flow through said air passage and into said induction passage in proportion to the v elocity of said air flow, a tube disposed within said inductlon passage and communicating at one end with said air passage intermediate said venturi and said fuel nozzle, the other end of said tube extending through said slot and into the space between said secondary induction passage throttles.

7. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary induction passage, a mechanically. operated throttle in said secondary passage, an air flow responsive throttle disposed in said secondary passage anteriorly of said mechanically operated throttle, a fuel well, a fuel nozzle projecting within said fuel well, an air tube disposed within said induction passage and extending longitudinally thereof, said air tube being open at bo-th ends and extending from a point anteriorly of said fuel well to a point posteriorly of said air flow responsive throttle when the latter is closed, said fuel nozzle including a portion extending within said air tube, the portion of said nozzle within said air tube being shaped so that the air ilow through said air tube will create an aspirating effect on said fuel nozzle to cause fuel to tlow therethrough.

8. A charge forming device for an internal 'combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary induction passage, a mechanically operated throttle in `said secondary passage, an air ow responsive throttle disposed in said secondary passage anteriorly of said mechanically operated throttle, a fuel well, a fuel nozzle projecting within said fuel well, an air tube. disposed within said induction passage and extending-longitudinally thereof, said air tube bein g open at both ends and extending from a point anteriorly of said fuel well to a point posteriorly of said air ow rcsponsive throttle when the latter is closed, said fuel nozzle including a bent portion terminating in a bevelled end portion extending within said air tube so that the air flow past said bevelled nozzle portion will create an aspirating effect on said fuel nozzle to cause fuel to flow therethrough.

9. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary induction passage, a mechanically operated throttle in said secondary passage, an air flow responsive throttle disposed in said secondary passage anteriorly of said mechanically operated throttle, a fuel well, a fuel nozzle projecting within said fuel well, a venturi disposed in said induction passage anteriorly of said air flow responsive throttle, an air passage communicating said venturi and said nozzle whereby air ow through said venturi will lcause fuel to flow through said air passage and into said induction passage in proportion to the velocity of said air ow, a tube disposed within said induction passage and communicating at one end with said air passage intermediate said venturi and said fuel nozzle, the other end of said tube extending into the space between said secondary induction passage throttles, and flow restricting means in said air passage intermediate said venturi and said tube.

10. A charge forming device for an internal combustion engine comprising a primary induction passage, a throttle valve in said passage, a secondary induction pas- 6 sage, a mechanically operated throttle in said se'condary passage, an air ow responsive throttle disposed in said secondary passage -anteriorly of said mechanically operated throttle, a fuel well, a fuel nozzle projecting within said fuel well, a venturi disposed in said induction passage anteriorly of said air flow responsive throttle, an air passage communicating said venturi and said nozzle whereby air flow through said venturi will cause fuel to flow through said air passage and into said induction passage in proportion to the velocity of said air ow, a tube disposed within said induction passage and communicating at one end with said air passage intermediate said venturi and said fuel nozzle, the other end of said tube extending into the space between said secondary induction passage throttles, and orilce means in said air passage to limit the bleed of substantially atmospheric air into said air passage through said venturi.

References Cited in the file of this patent UNITED STATES PATENTS 2,063,433 Grenat Dec. 8, 1936 2,573,093 Burson Oct. 30, 1951 2,617,638 Udale Nov. 11, 1952. 2,752,133 Egerer June 26, 1956 2,793,844 Olson May 28, 1957

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