US1582187A - Carburetor for internal-combustion engines - Google Patents

Description

April 27 1926.

M. C. MORRIS CARBURETOR FOR INTERNAL COMBLfSTION ENGINES Filed Oct. 14. 1925 Patented Apr. 27, 1926.

MAX oYnIL MennIs, or WESTMINSTER, Lennon, ENGLAND.

oannnnnron son IN'rnBNAL-GQMiBnSTiON ENGINES.

Application filed Getoh'er 14, 1925. Serial No.62,41 5

To all whom it may concern: I

Be it known. that I, MAX OYRIL Monnis, a subject of the King of Great Britain, residing at lVestmin-ster, in the county of Lon don, llngland, have invented certain new and useful Improvements in Carburetors for Internal-Combustion Engines, of Whichthe following is a specification.

Tl'iepresent invention relates to earburetors for internal combustion engines and more especially to such as are intended for use in connection with motor road "vehicles. I

The principal object of the present invention is to provide a carburetor which affords the following combination of features, namely, which is of simple and robust eonstruetion, which does not involve any complicated or delicate elements giving rise to di liiculty and expense in manufacture, which are easily damaged or put out of adjustment in use, which supplies a suitable proportion of fuel and'air mixture to the engine througl'iout the full range of opening of the throttle valve without calling for any manual operation during running beyond that of opening or closingthe throttle valve, which comprises simple *IHBJLHS providing for semi-permanent adjustment of the carburetor lor dilierent fuels or engines of different sizes or diiierentengine or atind spherie conditions, and which comprises eiiicient provision for starting the engine and running it idle with thetlirottle valve in the fully closed position; A further object is to attain the latter end whilst obviating the employn'ient of a very small starting or pilot jet which as is well known is usually einployed'fer the purpose mentioned and which is subject to the disadvantage thatit easily becomes choked.

With these objects in view, the present invention comprises av carburetor which in cludes in its construction a certain combination of elements to which no claim lSlDZiC G in the present application'such combination being the subjectot claims made in my cepending application Serial No. (367602 and in addition thereto anuuniliary fuel supply nozzle which isso combined with-the known elements as to co-operate' therewith to attain two main functions, namely, to correeta defect in the mixture proportions which arises at throttleopenings in connec-' tion "with the known ci'iiiibination of elements and to :iiterd means for engine starting and.

idling with the throttle valve in the "fully closed position. 'A construction of ear re tor embracing these features and by w the objects indicated are attained is illustrated in the accompanying drawings wherein like nui'i'ierals of reference indicate like parts in the several'figur'es. I

Figure l is an upright elevation looking from left to right of Figure 2 with the up per part of theauxiliary nozzle arm broken away.

Figure 2 parts in elevation, the section being taken substantially on planes'indicated by the stepped line 2 2 of Figure 1" and Figure 3 and at right angles to-the axis of the main passage throughthe carburetor.

Figure 3 is a vertical section on'thelin'e 3 3 of Figure 2. i I

Figure 4 is a fragmentary vertical section on the line P-4-Of'FigureBJ Figure 5 isa fragmentary upright sec tional view of a similar nature to Figure 2- and illustrating an alternative means for o controllingthe flow of fuel from the'a'uiiil iary nozzle. I v Figure 6 is a side elevation looking from left to right of Figure 5 with the auxiliary nozzle removed. I V Figure 7 is a section entire line of Figureli. p Figure 8 is a detail view showing alternative means for adjusting the position of the auxiliary nozzle towards or from theaxial line o'f the throttle plunger, v

Figure 9 is a detail view showing a re striction in the grooveon the throttle 11 ];u1'1ger. I i

' Referring to these drawings 33 c is" the main casing of the carburetor provided with a horizontal "passage therethro ugh coniprisingthe air inlet 5 and the mixture outlet 6. from a float chamber ll of conventional form (indicated in dottedlines in Figure Q'only) and :withthe fuel outlet orifice 52 at its upper extremity. Tl1e main nozzle is located in a vertical well 2 formed inthe casing and hereinafter terni'ed the nozzle chamber. jl is the throttle valve" cons sting of a plunger capable of being recipro-' catedvertically' across the main passage to control I the flow therethrough, it "eing guided injits movement ey an upright bore 14- i rmed in thec asir. 1nd inwl a sliding fit.

is an upright sectional view with 1 isthe main :i uel nozzle ted away obliquely to form an inclined face 7 on the air entry side and it carries depending from its lower end a tubular shroud 3 which is open at its lower end and closed at its upper end and which, following the movements of the throttle plunger, slides loosely up and down within the nozzle chamber 2 and over the main nozzle 1. 8 is a longitudinal opening in the tubular shroud 3 on the engine side thereof. A bore 34: is provided in the casing the said bore opening into the lower part of the nozzle chamber 2 and communicating through an orifice 9 with another bore 35 which is screw threaded and provided with a screw threaded plug 11 constituting an adjustable valve controlling the effective area of orifice 9. By turning this plug in one direo tion or the other the effective area of the orifice 9 may be varied, thus providing for the admission of a variable amount of extra air through the open end 36 of the bore and the orifice 9 into the nozzle chamber 2, from whence it passes up through the spaces between the nozzle tube 1 and the shroud 3 and the wall of the nozzle chamber 2 direct into the main air stream. Another inlet orifice 10 for admitting air into the bore 34 and thence into the nozzle chamher, is provided at the top of a vertical bore 37 formed in the casing, the said bore being open to the outer air at its lower end 38 and provided also with an orifice 30 at the side. lVithin this bore is located a ball 12 which normally rests upon a pin 40 extending across the lower open end 38 of the bore 37. A groove 13 is formed on the throttle plunger which provides a small channel for passage of air through the carburetor when the throttle is in the fully closed position, this groove being so disposed as to become occluded by the wall of the guide bore 14 as soon as the throttle is slightly raised.

The combination of elements so far do scribed terms the subject of claims in my copending application hereinbefore referred to and no claim is made in the present appli cation to this combination of elements per Se. The construction described it will be observeth provides avery simple and robust structure which is free from complicated and delicate details. The functions associated with the construction sofa]: described are briefly as follows. At small throttle openings the ratio of the air speed over the top of the main nozzle 1 and nozzle chamher 2, to the volume of air passingis high, due to the restriction of the passage at this point by the throttle piston and this ratio will steadily decrease with increasing opening of the throttle so that a steady gradient of correction is applied to counteract the disproportionate increase of fuel with in creasing volume of air passing which occurs in a carburetor wherein a simple nozzle is located in a choke tube or main passage of fixed cross sectional area, Another effect is that throughout the range of throttle opening, the main fuel nozzle being shielded by the shroud 3 from direct impact of the entering air,' the fuel issues therefrom in an upwardly directed stream, impinges upon the upper closed end of the shroud and is then thrown down again through the opening 8 in the shroud where it is caught up in the main air stream which has had imparted to it a considerable degree of complex whirling motion due to downward deflection by the inclined face 7 of the throttle plunger and lateral deflection by the cylin drical surface of the shroud. A very thorough atomization of the fuel is thus brought about. A further effect which arises from the construction described is that at small throttle openings the annular spaces between the main fuel nozzle 1, the shroud 8 and the wall of the nozzle chamber becomes filled with a very rich. fuel-air mixture, which serves as an immediately available reserve upon which the engine can oraw when the throttling opening is increased to accelerate. At very small throttling openings, however, the velocity of air over the main nozzle and therefore the suction thereon relatively to the volume of air passing would be unduly high without some provision, made to meet this defect, and the construction described embraces two provisions for making compensation relatively to this point, Thus the suction on the main nozzle during the very smallest opening movement of the throttle plunger is reduced owing to the fact that aircan pass directly through the carbu retor by way of the channellfl formed on the throttle plunger. h'loreover, the ad1nission of air to the nozzle chamber 2 by way of orifices 39 and 10 and bore 34: provides further for reducing the relative suction on the main nozzle by the admission of air upwardly and direct into the main air stream at or in advance of the main fuel outlet. This reduction of relative suction is opera live throughout a greater degree of opening movement of the. throttle plunger but when a certain opening has been reached the increafng suction of the engine automatically draws up the hall 12 into the position shown in. dotted lines in Figures Sand 4; thus closing the orifice l0 andfrutiiug oil the supply of air therethrough. The cilectire area of the orifice 5) may be varied by turning the screw threaded plug '11 in one direction or the other. which provides for the admission of a predetermined and permanent inleak of air from outside the carburetor through the open end 36 of the bore 35 and this it will be observed is operative throughout the entire range of movement of the throttle plunger. Thusis provided a ready nieans'f-or setting one andthc same carburetor for fuels otditferent quality or for engines of differentsizes or for different atmospheric or engine conditions. Moreover adjustment of the eltectivc area of the opening 9 co-operateswith the action of the ball valve 12 in that it determines the point at which the latter operates and this eo-operation in such that the desired object is attained. Thus assuming cert-sin conditions which require a larger proportion oi air to fuel than the carburetor happens to be adjusted for, the screw threaded plug 11 will be turned so as to enlarge the ettective area of the orifice 9 thus increasing the proportion of extra air and correspond ingly increasing the degree of diminution oi relative suctionon the main nozzle. The area of the orifice being invariable the increase ot'effective urea oli'jorilice 12 will have the effect oi? delaying; the operation of the ball 12 that is to say delaying; the point of t-hrottle'opening at which the sup-- ply of air tending to reduce the flow of fuel,

cut oil. This conforms to the assumed requirement of increased air proportion throughout the whole range of throttle opening. a i

It follows from the construction so far described however that as the throttle valve l is raised and with it the shroud 3 the obstruction offered by the latter to the pa; sage of air from the nozzle chamber 2 into the main air stream is progressively reduced, and when the throttle valve is nearly in the fully open position this has an appreciable efliec-t in admitting a greater proportion of extra air than would otherwise he the case and thus causing a falling oil of the relative suction 0n the main fuel orifice and con sequent reduction in the proportion of fuel which'is not desired at this point.

It is the object of the present invention to remove this defect and, as hereinbetore stated to adapt the carburetor at the same time for engine sterting'nnd idling with the throttle valve in the fully closed position. I This double object is attained by the provision of a secondary or auxiliary fuel nozzle which is adapted to deliver tucl through the casing and in-to the carburetor at a; point which coincides with the posit-ion occupied by the channel 13-wl1en the throttle valve is in the fully closed posit-ion. This auxilia'y nozzle may be adapted to deliver the fuel through the casing without any provision for admission of air at this point, or it may be arranged to protrude into an orifice large in relation vto the size of the auxiliary nozzle so that air can enter around it, or means may be provided for admitting eirrthrough independent orifices in theorising in the. immediate vicinity of the auxiliary nozzle. "lhc amount of fuel El;(ll'i)ltt(l by the auxiliaryqnozzle may be varied by varying the amount or air ad mitted at or in its iu'in'iediate vicinity,

which may be effected for exain le by varying the position of the nozzle towards or from the, axial line oi the throttle valve or by varying the position which the auxiliary nozzle occupies within the bounding wall of a relatively large orifice in the curing when such is provided.

Referring now more particularly to F ores 1-3, 15 is the auxiliary nozzle carried by an arm 1? integral with a hollow boss 42 and provided with an internal; iuel channel all. T he said boss 42 is attached to the lower purt oi the carburetorcasingby the assembly screw l3 and the fuel has access to the auxiliary nozzle through the channels and in the screw -13, the groove 47 :l" .rined upon the said screw, and the channel t l-l in the arm 1?. This auxiliary nozzle 15 protrudes into a conical hole 16 in the all of the casingwhich hole is large relatively to the size of the portion of the auxiliary nozzle which enters it. The relative positions are such that when the throttle valve is in the fully closed position, fuel issuing troni the auxiliary nozzle is delivered into the chennel 13, so that on the engine bciun'turncd, air is drawn through the carburetor by way of channel 13 and the suction produced also draws in a proportion of fuel troin the euxih iary nozzle 15 The amount of fuel delivered by the auxiliary nozzle is varied inthe form shown by adjustment of the latter towards or from the axial line of the throttle valve. This adjustment is effected by erranging that the arm 17 carrying the auxiliarynozzle 15 tends normally to press the latt-r towards the axial line of the throttle valve whilst between the arm 17 and the cosine oi"? t re calburetor a linger nut 18 is provided worl upon a screw threaded stud 19 carried by the carburetor casing: By turning the finger nut 18 the arm 17 can be sprung baclc carrying the auxiliary nozzle 15 withitso us to any the admission of air around the nozzle and consequently the suction eliect' and the proportion or fuel which is admitted therefrom. Theresilicncy ot'lhe arm 17, which is naturally of metal, permits alllthe move-- ment required the H1 :iiinuiu ol' i'iecessary inoveinent being small; in in i o supply additional air to this preliinn mixture,. :1 plate 20 working on u machined 1Q i 4 1 i nue 3k on the side Or Lie casing may be p1o vided this plate being furnished wi h e ll11-' gerlever 21, whereby it may be turned about the stud by which the said plate is pivoted to the casing. ,Theplate is: provided with a number of holesQS which may be brought into any desired de ree of coincideuce with cori pondingholcsQl (Finiijire so as to admitmore or less additional air i he recess an aperture 51 is provi as may be desired. Thus a sufficient supply of fuel and air mixture is supplied for starting the engine and running it idle, with the throttle valve in the fully closed position.

As has been previously mentioned, the channel 13 is so disposed that it may be cluded within the vertical uide way 14. during the smallest opening movement of the throttle valve. Stated otherwise, when the throttle valve is in the closed position the said channel very close to the top of the passage through the carburetor. The auxiliary nozzle being adapted to deliver fuel through the casing at this level, it will be apparent that when the throttle valve approaches the completely open position (see the dotted lines in Figure 3) the auxiliary nozzle will be uncovered and will deliver an additional supply of fuel into the carburetor which will overcome the defect hereinbefore referred to, namely, the falling oil. in the proportion of fuel which occurs at large throttle openings due to the reduced degree of obstruction oti'ered by the lower extremity of the shroud 3 to the upward p1. re of air through the nozzle chamber 2.

The provision of means for controlling the. out-flow of fuel from the auxiliary nozzle by means of variable air admission at or in the in'nnedi ate vicinity of the said nozzle has a distinct advantage in this respect, namely that without any such arrangement the orilice for supplying fuel for the purpose of starting and running the engine idle with the throttle closed would necessarily be extremely small, and very small jets are, as is well known, subject to choking by small solid impurities in the fuel and to other defects. lVith the controlling arrangement described, however, any convenient size of aux iliary jet as may be required for its intended function at full throttle opening may be employed.

Qther means for admitting a controlled supply of air in the immediate vicinity of the auxiliary nozzle appear in Figures 5, (i and T. The extremity of the auxiliary nozzle forms a working lit in a central orifice 27 made in a. shallow thiinhle which worlcs within a cylindrical recess 49 in the wall of the carburetor casii'ig. and is providea'l with a small operating lever 26; In the bottom or 1" .ed in the casing through which fuel from the nozzle may pass into the interior of the carburetor when the throttle valve is fully raised, or into the channel 12) when the said valve is {fully closed, as the case may be. The thimble 25 is also provided with an eccentrically disposed orifice 28 which, by operating the lever 26 to turn the thimble 25 in its recess 49, may be brought into any desired degree of coincidence with another orifice 29 in the casing in order to vary the air admitted immediately in advance of the auxiliary n0zzle 15 and on the engine side thereof. As an additional provision for restricting the flow of fuel from the auxiliary nozzle, the channel 13 may be contracted immediately adjacent to the said nozzle and on the engine side thereof. In the case of the arrangement shown in Figures 5, 6 and 7, for example, the portion of the said channel which extends between the point of fuel admission from the auxiliary nozzle 15 and the point of air admission through the orifice 29 may be contracted to a very small passage as shown in Figure 9.

Another way of controlling the amount of fuel issuing from the auxiliary nozzle. 5 with a. construction similar to that shown in Figures 14-1 would by varying the position of the said jet in relation to the bounding lineof the orifice 16. Thus the arm 17 might be adjusted angularly so as to set the auxiliary nozzle towards or from that side of the opening 16 which is towards the. engine or oulct side 6 of the carburetor and the proportion of fuel admitted would be greater the nearer the nozzle were located to the engine side of the opening 16.

it is preferred, however, to control the fuel by adjusting the position of the auxiliary nozzle 15 towards or from the axial line of the throttle valve and another method of effecting this is shown in Figure 8. Here the arm 17 is provided at its upper extremity and beyond the auxiliary nozzle 15 with a fork 30 and the said arm is normally so disposed as to support the auxiliary nozzle in an extreme "position away from the axial line of the throttle valve 4-. A screw threaded stud 31 projects from the casing and between the two limbs of the fork and is provided. outside the said fork with a finger nut 32, by turning which the position of the auxiliary nozzle towards or from the axial line of the throttle valve may be adjusted. 1? making the stud 31 of such size as to fit closely between the limbs of the forlr 80, any maladjustment through angular movement of the arm 17 may be prevented.

lVhat I claim and desire to secure by Letters Patent of the United States is:--

1. In a carburetor, the combination of an air inlet, a main fuel supply, a mixture out let, a throttle plunger provided with an inclined face, and an auxiliary :fuel nozzle, said auxiliary fuel nozzle being covered by the throttle plunger when the throttle is in closed position, but adapted to be uncovered by the inclined face of the throttle when the throttle has been opened a predetermined amount.

2. In a carburetor, the combination of an air inlet, a main fuel supply, a mixture outlet, a throttle plunger provided with a channel, and an auxiliary fuel nozzle, said auxiliary fuel nozzle communicating with the channel in the throttle plunger and themixture outlet when the-throttle is in closed position, and adapted to have.said coimnunica tion cut oil when the throttle is openeda predetermined an'iount.

3. In a carburetor, the'cmnbination'of an air inlet,- a main fuel inlet, a mixtureoutlet, a throttle pl unger provided with an inclined faeeand a channel, and an auxiliary fuel nozzle communicating with-the channel 'in' the t-l iro-ttle plunger and the mixture outlet when-t e throttle is in closed position, and adapedto have said communication with are mixture outlet cut off lwhenthe throttle has been opened a predetermined amount, and reestablished when thethrottle has heen opened a still further amount.

4.111 a. carbureter, the combination of a main air inlet, a main fuel supply, a mixture outlet, a throttle plunger provided with an inclined face, and an auxiliary fuel and air inlet, said auxiliary inlet being covered by the throttle when the throttle is in closed position, but adapted to be uncovered by the inclined face of the throttle when the throttle has been opened a predetermined an'iount. I Y

5. In a carburetor, the combination of a main air inlet, a main fuel inlet, a mixture outlet, a throttle plunger provided with a chanueland an auxiliary fuel and air inlet, said auxiliary inlet communicating with the channel in the throttle plunger and the mixture outlet when the throttle is in closed position, and adapted to have said communication cut off when the throttle is opened a predetermined amount.

('3. In a carburetor, the combination of a main air inlet, a main fuel inlet, a mixture outlet, a throttle plunger provided with an inclined face and a channel, and an auxiliary fuel and air inlet conin'iunicating with the channel in the throttle plunger and the mixture outlet when the throttle is in closed position, and adapted to have said connnunication with the mixture outlet cut oil' when the throttle has been opened a predetermined amount, and reestablished when the throttle has been opened a still further amount. 7.

T. In a carburetor, the combination of a main air inlet, a main fuel inlet, a mixture outlet, at throttle plunger provided with an inclined face and a channel, an auxtle has been opened a predetermined amount,

and re-established when the throttle has been opened a still further amount.

8. In a carburetor, the combination of a casing, a main passage therethrough with an air'in'let at one end and afmixture outlet at-theotherend,a main fuel supp' said passage, 21 throttle valve comprising a )lun er ada ated to be reciorocated' in o l vides a relatively small passage from the air inlet side tothemixture outlet side of the "main passage when the throttle is in fully closed position, and which is closed by occlusion *ithin the wall of the guide ay' immediately the throttle plunger is sli htly j ope-nedyandhnaux ary fuel 'iiozz'lea ape ed to deliver an auxiliary supplyof fuel in to the channel when the throttle Valve is closed.

9. In a carburetor, the combination of a casing, a main passage therethrough with an air inlet at one end and a mixture outlet at theother end,a main fuel supply to said passage, a throttle valve comprising a plunger adapted to be iieciprocated in a guideway formed in the casing and across the main passage between the air inlet and the mixture outlet, thesaid plunger having a channel formed in its periphery which provides a relatively small passage from the air inlet side to the mixture outlet side of the main passage when the throttle is in fully closedpositiou, and which is closed by occlusion within the wall of the guideway innnediately the throttle plunger is slightly opened, and an auxiliary fuel nozzle adapted to deliver an auxiliary supply of fuel into the channel when the throttle valve is closed and to deliver an auxiliary supply of fuel in to the main passage when the throttle plunger has nearly reached its fully opened position.

. 10.111 a carburetor, the combination of a casing, a main passage therethrough with an air inlet at one end and a mixture outlet at the other end, a main fuel supply to said passage, a throttle valve coi'i'iprising a plunger adapted to be reciprocated in a guideway formed in the casing and across themain passage between the air inlet and the mixture outlet, said plunger having a channel formed in its periphery which provides a relatively small passage from the air inlet side to the mixture outlet side of the main passage when the throttle isin fully closed position, and which is closed by occlusion within the wall of the guideway immediately the throttle plunger is slightly opened, an auxiliary fuel nozzle adapted to deliver an auxiliary supply of fuel into the channel when the throttle valve is closed, and to deliver an auxiliary supply of fuel into the main passage when the throttle plunger has nearly reached its fully opened position, the said nozzle protruding into an opening in the side of the casing relatively large in relation to the size of said nozzle, and means for adjusting the position of the auxiliary nozzle towards or from the axial line of said throttle plunger.

' 11. In a carburetor, the combination of a casing, a main passage therethrough with an air inlet at one end and a mixture outlet at the other end, a main fuel supply to said passage, a throttle valve comprising a plunger adapted to be reciprocated in a guideway formed in the casing and across the main passage between the air inlet and the mixture outlet, the said plunger having a channel formed in its periphery which provides a relatively small passage from the air inlet side to the mixture outlet side of the main passage when the throttle is in fully closed position, and Which' is closed by occlusion within the wall or" the guideway immeditely the throttle plunger is slightly opened, an auxiliary v fuel nozzle adapted to' deliver fuel through the wall of the easing into the channel upon the throttle plunger when the latter is in fully closed position, and directly into the main passage when the said throttle has nearly reached its fully opened position, means for admitting a supply of air variable at will through the casing in the immediate vicinity of said auxiliary nozzle and means for admitting a supply of air Variable at will from outside the carburetor into the main passage at a point beyond the throttle valve and on the mixture outlet side thereof.

MAX OYRIL MORRIS.

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