_Aug. , '1941- G. M. BICKNELL 2,252,958 CARBURETOR STRUCTURE Original Filed Aug. '7, 1936‘ 2 S?eets-Sheet 1

‘ INVENTOR. 7" ’ Geo/:98 M ?/cl-ne/L BY .

ATTORNEY. - Aug. 19,1941.» VCARBURETORGM‘BlCKNELL STRUCTURE" _ ~ 2,252,958' ~ -

Original Filed Aug. 7, 1936 2 Sheets-Sheet 2'

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, . ~ “Y ‘INVENTOR. ‘ ’ ~ > Q6098} M 5/0676”. BY'

ATTORNEY. . Patented Aug. 19, 1941 ’ 2,252,958

I UNITED STATES PATENT OFFICE

2,252,958 .

CARBURETOR STRUCTURE ' v I I George M. Biclmell, St. Louis, Mo., assignor to Carter Carburetor Corporationrst. Louis, Mo., a corporation of Delaware Substituted for abandoned application Serial No. 94,764, August 7, 1936. This application July 19, 1939, Serial No. 285,410 2 Claims. - (c1. 7261-34) This invention relates to carburetors and par celerating pump which will effectively prevent ticularly to arrangements for preventing the with the pulling over of fuel through the accelerating drawal of fuel through the accelerating pump by pump when the carburetor is operated under high

suction when the carburetor is passing a large‘ suction conditions. ’ , V , volume of air‘. The present application is sub Otherv objects and advantages oiv the invention stituted for-an abandoned application in the name will appear from the following description and of the same inventor, Ser. No. 94,764, ?ledv Aug. accompanying drawings referring to which: 7, 1936. ‘ Figure l is a vertical, sectional view of‘a' form Modern carburetors for automotive engines are of carburetor embodying the invention. ‘ ‘ usually provided with accelerating pumps for 10 Figure 2_ is anenlarged view of a portion of supplying additional fuel when the engine is the structure in Figure 1. being accelerated. ‘Since the carburetor is also Figure 3 is an enlarged view of the discharge provided with a main nozzle and an idling port nozzle of the accelerating pump. __l ‘j which, generally, are calibrated for supplying The carburetor shown includes. a, downdraft the entire normal requirements of the carburetor mixture conduit having an air inlet horn I, mix during constant speed operation, it is undesirable ing chamber 2, and a series of venturis 3 and I. to have the accelerating pump discharge at such A choke‘valve 5 is pivotally mountedin the air time because the additional fuel would cause the horn, and a throttle valve 6 is mountedon pivot engine to be supplied with an unduly rich mix 6a in the lower part of the mixing chamber. ,The ture. The accelerating discharge nozzle fre reference character 99- indicates an air cleaner quently is positioned so as to discharge a com or strainer which is applied to‘ the inlet end of pact jet into a part of the mixture conduit where the air horn or mixing condult'.' The interior relatively high suction prevails'at least at times, construction of the air ‘cleaner not shown as during normal operation of the carburetor, which it may be of any desiredltype but it may be‘noted suction tends to draw fuel from the accelerating 25 that the object of this device is to remove dust system. ‘ ' and dirt from the air and also to silence the flow In order to avoid such discharge from the ac of air through the carburetor so that there is . celeratlng passage due to suction, there have a certain amount or restricting died on the air been suggestions to provide an air bleed from ?ow. , » this passage as, for instance, in Henning Patent 30 A fuel bowl 1 adjacent the mixture passage No. 1,915,930 which provides an air bleed com encloses an accelerating pump cylinder 8, piston municating with the inside of the mixture con 9, and piston rod l0 controlled from the throttle duit. This arrangement has proved not wholly by means of a crank ll, link l2, and lever l3 satisfactory due to substantial depression which pivoted to‘the fuel bowl cover. The pump cylin exists even inthe' air inlet portion of the‘ car 35 der communicates through passages I4, 15, and buretor at higher speeds of operation. Such I6 with‘an inclined Ori?ce I'I leading upwardly depression, though less than that which exists in and outwardly through the wall of the mixture the high suction zone of the carburetor adjacent conduit. Ori?ce I1 is plugged at its upper end, the venturls, nevertheless seriously reduces the as at I8. I ' e?ectiveness or the bleed. This difficulty is en 40 During normal operation, fuel is fed from an? hanced by the air cleaner which is always mount other portion of the fuel bowl through calibrated ed on the air horn of an automobile carburetor Jet l8, controlled by metering rod 20, and main and restricts the entering air. Ball Patent No. nozzle 2| discharging into the throat of primary 1,358,498 provides an outside air bleed for the venturl I. ' accelerating discharge passage, but the arrange 46 Upward movement of piston '9 draws fuel ‘from ment is such that the accelerating iuel cannot be bowl 1 through a passage 22, past check ball 23 discharged in a. jet into the mixture conduit and, into passage II, and lowering of the piston forces indeed, will likely spill out through the air bleed. fuel past check ball 24 into ori?ce‘or chamber Other constructions developed for the same pur l1_ and the mixture passage through an auxiliary pose require a valve to prevent the squirting of 50 nozzle, generally indicated at 25. The general fuel into the outer atmosphere or constant level “features of the carburetor structure described chamber of the carburetor and this valve is not above are well known and, in themselves, do only expensive but frequently is notreliable. not constitute the present invention. The object of this invention is to produce an The accelerating discharge nozzle includes a _ arrangement for the discharge outlet of the ac- 65 body having a threaded upper Portion 25 mount 2,252,958 ed in orifice l1, and a tip 21 discharging into a inch. It will be understood that the length of relatively high suction :zone of the mixture con these passageways has an effect on the restriction duit adjacent venturis 3. The threaded portion presented thereby but good results were secured of the auxiliary nozzle also includes a screw with a device constructed in approximate ac driver slot 93. Intermediate its ends, nozzle 25 cordance with the scale used in Figure 2. is provided on its outer surface with an annular When the proportions indicated herein are vrecess 28 ‘separated from tip 21 by a collar 29 used, the ?ne stream squirted through the jet which substantially seals therecess from the 3| will shoot directly through the passageway port 91 of passage I1 and the- mixture conduit. 30 so that it will not be impeded by striking the Collar 29 is provided with a very narrow annulus walls thereof and the stream will not, according 29a, which, being made of brass is capable of ly, be broken into ?ne drops until it gets out into being slightly deformed to fit the exact contour the mixing conduit beyond the end of the pas of the bore 91. ' sage 30. - Extending longitudinally through the nozzle 22 ‘ The accelerating nozzle described comprises a is a boreor passage‘ 30 having a restriction 3| 15 relatively simple unit which functions satisfac intermediate ‘its ends. When the nozzle is prop torily to ‘supply partially atomized fuel to the erly assembled with the carburetor body, as shown mixture passage and to prevent pulling over of in the figures, bore 30 communicates with the at fuel from the accelerating pump by suction. Ob ' mosphere through radial passages 32, annular viously, various features of the illustrated struc recess 28, and a passageway 33 connecting ori?ce ture may be modi?ed as will occur to those skilled H. with ‘the atmosphere outside the carburetor. in the art and the exclusive use of all such modi The capacity of the vent ‘due ‘to the effective ?cations as come within the scope of the append areas ofiradial passages 32, annular recess 28 and ed claims is contemplated. the passageway 33 is preferably greater than the I claim: 1 } capacity of the bore 30 .so that substantially all ~ 1. In a carburetor, a mixture conduit having a ~ the suction applied to bore 30 from the mixture restriction forming a suction zone,‘an accelerat conduit is killed by the open vent 33 so that it ing fuel system including a pump, a passage con cannot be-e?‘ective to pull fuel through the ori?ce necting said pump with said conduit at one side - 3|. The effectiveness of the air ducts 32, 28 and of said zone including a discharge nozzle having 33 may be varied to conform with requirements its bore terminating adjacent and substantially due-to other carburetor features. . ‘in line with the mixture conduit wall for dis During operation of the accelerating pump, charging a jet of accelerating fuel across said . liquid fuel under pressure will be forced through conduit, and a suction breaking bleed passage restriction 3| in nozzle. 25 and ejected in a very intersecting the. inner end of the bore of said fine stream or jet past radial passages 32. Pas nozzle and communicating with a zone of sub sage- 30 should be made sufficiently wide and short stantially atmospheric pressure, said nozzle hav so that the jet will not strike the walls thereof. ing a restricted fuel ori?ce immediately anterior No fuel will escape outwardly through passage to said bleed passage for forming the normal 32, due to the pressure of the ?uid stream when pump discharge into a jet, the portion, of said emerging from restriction!!! and :to the angle 40 bore posterior to said bleed passage being coaxial between passages 32 and bore 30. When the with said orifice and su?iciently wide and short pump is inactive, suction communicated to bore so that said jet will be projected therethrough' '1 30 from the mixture passage will be substantially and beyond the mixture conduit wall during pump broken by air bleeding through the passages 32 operation substantially without wall friction. and aperture‘ 33, preventing drawing of fuel 2. In a carburetor, a mixture conduit surround from the accelerating system. ing a ‘high suction zone including a Venturi tube The outside vent passageway is shown open and a lesser suction zone adjacent the same, a ing downwardly into a pocket between the fuel main fuel supply system including a nozzle un bowl and mixture conduitgvbut the passageway‘ der the in?uence of said high suction zone, an may be otherwise disposed so as to open through 50 accelerating fuel supply system including a any convenient part of the carburetor body. In pump, an accelerating nozzle having a passage the arrangement shown, the vpassageway 33 is connected with said pump at one end and its substantially protected against dust and foreign other end comprising a bore opening into said matter circulating in the vicinity of the carbure lesser suction zone adjacent the conduit wall. a tor. The protection is provided, in the present suction breaking bleed passage intersecting ‘the instance, by the location of the inlet of passage‘ inner end of said bore and communicating with 33, but for greater assurance of protection from a zone of atmospheric pressure outside the mix dust. a strainer or ?lter 96 may be provided. ture conduit, and said nozzle providing a re For the convenience of those skilledin the art stricted fuel ori?ce in said fuel passage adapted who wish to use the invention, a practical em 60 to-form a liquid fuel jet immediately anterior bodiment may be dimensioned as follows: If the vto and coaxial with said bore, said bore being restricted ori?ce 3| is made not greater in area su?‘iciently wide and short so that said jet will than .000'75 (#68 drill size) then the passageway be projected through said bore and beyond the 30 may be made .00169 or #56 drill size. The conduit wall during normal operation of said two passageways 32 may be of #58 drill size so 65 pump substantially without striking the walls of as to total .00276 in area, and the passageway 33 said bore. said bleed passage being larger than may be drilled with a #42 drill which will give said ori?ce so as to substantially satisfy suction the passageway an area of .00686. All of the applied to said ori?ce from’ said mixture conduit. above areas are given in decimals of.a square, GEORGEv M. BICKNELL.‘