US1897102A - Charge forming device - Google Patents

Description

CHARGE FORMING DEVI GE Filed April 50, 1.929

4% Mb Q9 5 e7 A22 Cay g 3% A24 54:4 (2 m Patented Feb. 14, 1933 FFEQE FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed April 30,

pipes connected with the primary carburetors,

while receiving air'when required, through an air manifold having a single air inlet for supplying air to all the secondary mining chambers.

An example of a charge forming device of this character is disclosed in the copending application of Fred E. Aseltine, Carl H. Hindi, and Vilford H. Teeter, Serial No. 288,683, filed June 27, 1928.

In the device disclosed in the above application and other earlier devices of similar character, various means have been provided to control the proportions of air and fuel in the mixture under various operating conditions for the purpose of supplying to the engine amixture having the desired proportions to properly operate the engine under any operating conditions. Among these proportioning devices are certain structures for regulating the mixture proportions by controlling the admission of air to the carburetor, and it is the primary purpose and object of the present invention to provide simple and improved means for regulating the admission of air to a carburetor whereby the des red mixture is formed therein under all operating conditions.

In earlier devices of this character, a suction operated auxiliary valve is provided which is opened as the throttle is opened to admit auxiliary air under certain operating conditions and means are provided to normally retard the opening movement of this *alve, said retarding means being controlled in its action so that it is rendered ineffective on sudden openings of the throttle which cause a relatively great increase in suction effective to open the valve, in order to permit the air valve to open freely under these conditions. The means for controlling the re- 1929. Serial No. 359,320.

tarding means such as heretofore provided, is more or less complicated in construction and it is a further more specific object of the present invention to provide a carburetor having an auxiliary air valve and means for normally retarding the opening thereof with improved and simplified means for controlling the effectiveness of said retarding means, which is positive in its action and easy to manufacture.

A still further feature of the invention resides in the provision, in a carburetor having a main air valve and an auxiliary air valve of the type described, of a retarding means normally retarding the opening movement thereof and means operated by the main air valve for controlling the effectiveness of the retarding means which controls the opening of the auxiliary air valve.

According to the present invention, these objects are accomplished by the provision of a. dash pot resisting the opening movement of the auxiliary air valve, the resistance of which is controlled by a piston mounted in an auxiliary cylinder adjacent the dash pot cylinder and having passages therethrough which, under certain circumstances permit escape of liquid from the dash pot cylinder, thus permitting substantially unretarded movement of the auxiliary valve. The passages in thepiston are normally out of re ister with the passages in the dash pot cylinder, but are adapted to be brought into registry therewith by action of the main air valve on sudden increase of suction within the carburetor in the manner fully set forth in the body of the detailed description which follows.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of'one form of the present invention is clearly shown.

In the drawing: 7

Fig. 1 is a vertical, longitudinalsection through a charge forming device in which the present invention is embodied and the intake port associated therewith.

Fig. is a transverse vertical section on the i line 2-2 of Fig. 1'. w

' Fig. '3 is a 'fragmentary,detail section on the line 3-3 of Fig. 1.;

Fig. 5 is a detailfvi w 1 f th au il y piston. g V

The device disclosed comprises a main air manifold having three outletbranchesf v p the middle branch 1'2being shown-herein'.-

Each of thesebranches communicates with one of the mtalep0rts 14of a multi-cylinder 1 engine. These outlet branches are each prop, videcl with anattaching flange l6 for secur 1 ing the manifold to the engine block inthe usual" manner, Adjacent the inlet of the manifold'is-providedf a: fl-ange .-18.to which the main carburetor unit is adapted to be at a v i teriorgends ofx primarymixture passages 64,

. i The carburetor. unit comprisesa-main hous-. f

' ing having'an attaching flange 22 adapted tached, as shown in Fig.1..

' to be secured toflange 18by screws 24." An

bers 40,"the constructionof which is briefly air..inlet horn 28..is secured'in positiontoi] register with on opening in the upper-wall of housing 20, in any suitable way. A cast '-ing 30, having certain 'dashpotchambersy and fuelpassagesformed therein, issecured by-'screwsto' the lower wallof'housing 20,

and a sheet metal fuel bowl 32is'he1d 'tight' against an annular shoulder 34onthe housing 20 by any suitable means; I Fuel is con-" ducted from a main source of supply .to the:

fuel bowllthrougha conduit not shown herein-, .and the .fiow fuel to. the bowl is controlledby a floatll36', operating in theusual manner to maintain a substantially constant, level of 'fuel therein. 1 1*" Fuelilows from bowl 32itoi gof primary fuel-'n'ozzlesSS, one of whlch islodated: ineach of the primary mixing. chamdescribed hereinafter. The fuelconduitbetween thefuel bowl and'the nozzles comprises a vertical fuel passage 42 communicating at its'upper end with ahorizontalfuel canal/i4,

the above mentioned application. 7

; Fuel is lifted some. fi elibo'wl through the above described fuelpassages and nozzles 38 to thei niXing chambers 'by'thesuction therein, Closingmovemeiits" of the throttle cause a reduction in mixi'ngchamber suction,

which might permit the" fuel column were sufficiently to cause a temporary fuel ste ing of theengine' unless means were provided to prevent it. For this purpose a checkvalve' 54 is provided in an enlargedchamber 56 at the junction ofchannels 42 and 44,-

sages.)

fold a 'tionary guidesleeve 84, fixed in the' housing reduction of'mixing chamber suction seats on, the bottom of its chamber, preventing downward jflow of the fuel.

Each primary fuel nozzle isprovided with .a main fuel outlet-58 in'thetop of the nozzle and asecondary-fuel outletocomprisin'g two orificesI60 and-62 in the vertical wall of the I nozzle near the bottom of the-mixing chamber. At.relatively'highspeeds the mixing chamber suction isen'ough to lift-fuel from the -im ainioutletj'as well as from orifices 60 and 62. .At idling, or low speed operation under load, however, the suction is suflicient to lift fuel onlyj to some point between the top of thenozzle and orifices 60 and 62, fuel flowing from theseorific'es-by action'of grav mixing chambers comprise the'enlarged air-*- which are parallel-to. eachv other and-closetof n gether as indicated inthe drawing. 2 When the carburetor attached- .to the "manifold,

these passages register wi henance which convey the .priznary mixture to thesecondary {mixing chambers, as fully disclosed in the copending applicationreferredto. Restrio. tions 66 separate the primary mixing chambers from the remainder ofthemixture pas- Y across all the primarymi x ture passages con ftrols the Iflow therethrough; and is provided T V H '95" Aesingle throttle ValVejBS, which-extends loo 'in'g: application and which forms no-part of. i.

the present invention. The,middle primary;

mixture passagezconnectsrwithra tube-.72, fixedfm 'themanifoldbranchr12, which conveys the primary mixture, to the--secondary mixing ch mber in thatbranch of the ma n- Substantially all the air entering the car-i buretor flows through the air, horn 28, controlled by a main air valve .74, normally :held against a seat;7()'- by a spring T8received between the valve and aflange 80' projecting from a sleeve 82 slidably mounted'on a staa 20, and serving as a guidejsleeve-for, the "stem 86 to which the'air valveg-is'secured. n

' When it isdesir'edjto choke theicarburetor to start the engine, theflange is adaptedto be lifted by an arm 88, as described in the above copendingapplicaiton, until the upper 7 end ofsleeve 82 engages 'thevalve to hold it against its seat. Sufiicient'air'tO carry the starting fuel from the; nozzles to'the intake po'rtsis admitted through an elongaed slot 90 Qrmed in a plate 92 secured to the housing, 2O,assh0wn in Fig.1.

Theva lve74 admitsair to amainair chainber 94v from which air flows to the, primary I m x ur Pass s thr ugh an erifi e; 6" in the floor of the air chamber and to the secondary mixing chambers through a passage 98, which connects with the inlet of the manifold 10. A manually operable throttle 100 and a suction operated valve 102, secured to shafts 101 and 103 respectively, control the flow of air through passage 98 and the operating connections for said valves are fully disclosed in the above mentioned application.

On opening of either throttle 68 or 100, the suction in the air chamber 94 is increased and the air valve is opened against the tension of its spring to admit additional and increase the quantity of mixture supplied to the engine. The opening of the valve must be retarded to some extent, however, to prevent admission of sufiicient air to lean the mixture. A dash pot is pro ided to ac complish this result and to prevent fluttering of the valve comprising a cylinder 106 forming part of the casting and a piston 108 secured to the valve stem 82 by any conventional means such as a nut 110 threaded thereon.

The lower end of the dash pot cylinder is closed by a solid plug 112 screwed into the cylinder and passage 114-, leading from the dash pot cylinder to a small auxiliary cylinder 116, formed in the casting 30 adjacent the said dash pot cylinder, allows escape of fuel from the dash pot cylinder on ddwnward movement of the piston in the manner set forth in detail hereinafter.

In order to enable a better understanding of the present invention, which relates to means controlling the motion of the suction operated valve 102, the operation and function of said valve will be very briefly set forth. The purpose of this valve is to temporarily retard the flow of air through the main air passage on opening of the throttle 100 to prevent an increased supply of air reaching the secondary mixing chambers before the increased supply of heavier primary mixture, resulting from increase in suction at the jets, reaches the said mixing chamber and toincrease the pressure differential on the primary mixture tubes so as to reduce the time necessary for he primary mixture to reach the secondary mixing chambers, because of the resulting increase in velocity of flow through the said tubes. By means of a fuel pump, which is briefly described later and is fully described in the above mentioned application, additional fuel is injected into the primary mixture passages on opening movements of the throttle to form the enriched mixture necessary for accelerationand the auxiliary air valve 102 reduces the time interval required for such mixture to reach the secondary mixing chamber, while simultaneously increasing the interval required for pure air admitted through passage 98 to reach said secondary mixing chamber in the manner above described. lhe auxiliary air valve thus enables the enriched primary mixture to reach the secondary mixing chambers as soon as the increased supply of air, so that the mixture supplied the engine ports is temporarily enriched.

Under certain operating conditions it is not desirable to retard the opening of the auxlliary air valve appreciably and, further, it is not necessary to retarl the opening of said valve to the same extent at all times. According to the present invention means are provided for retarding the opening of the auxiliary air valve and means for coutrolling the efl ectiveness of said retarding means which is operative to vary the resistance offered by said retarding means under different operating conditions, and under certain predetermined COl'lCllbiOllS to substantially eliminate this resistance and permit the valve to open freely.

This retarding means comprises a da pot having a cylinder 120 in which slines piston 122 secured by a nut 12%, or in an. other desirable manner to a rod 126, pivot-all connected at its upper end to a bell cranl lever 128, pivoted at 130 on the main housin 20. The other arm of the bell crank lever 128 is connected by a pin and slot connection 132 to an arm 13% secured in any desirable 1312131- nor to the shaft 103 on which the auxiliary valve is secured. Obviously, any opening movement of the valve 102 will force the piston 122 downwardly, such movement being normally resisted by the pressure of the fuel below the piston which can normally escape only by leakage past said piston.

Under certain circumstances, it is desired to reduce the resistance offered by the above described dash pot to.the opening movement of the auxiliary air valve and, as has been indicated above, under certain operating conditions it is desirable to entirely relieve the dash pot so that the valve opens substantially freely. As an example of conditions when free opening of the valve is desirable, it may be assumed that the car, on which the carburetor is used, is coasting relatively rapidly with the clutch engaged and the throttle Valve 100 closed. Now, when the car reaches the end of the coast and the throttle is opened, it is not desirable to enrich the mixture because the engine is already running at relatively high speed and, therefore, it is not de sirable to retard the opening of the auxiliary air valve appreciably. Further, the requirements for enrichmentof the mixture are not the same when the throttle is opened through different distances or from diiferent positions, hence it is not desirable that the resistance offered by the dash pot to movement of the valve shall be always tne same.

To variably control the resistance of the dash pot for the auxiliary air valve so as to enable it to offer resistance to the opening of the valve in the manner above indicated as Y a desirable, thecylinder 120 is provided with a passage 136 through its wall whichcommunider 116 is hollow piston 140 having a series of l1oles142 in its side. wall communicating ,Withthe hollow interior of the piston. These holes are normally out oftregistry with the orifice 1-86,but are adapted to'be -brought into registry therewith by pressure of the fuel forced from the main air valve dash pot through the passagell l against the, solid bottom 144 ofthe piston 14:0. When the piston 140 is lifted so that the channel 137is in" exact registry with the passage 136," fuel is through passage 136 and orifices142,- relieving the pressure againstfthe piston 122 and permitting substantially free opening-of t -e air-valve. Obviously if'the'piston 140 isnot lifted to a position where the passage-136 is inexact registry with theg channel'137,the

flow through the passage-is to some extent restricted and the dashvpotloiferssome' resistance tothe opening-ofthevalve 102,

such-operating conditions as will'cause a'sud denand great increasein the suction effective channel138 .are'onlypartly in' register; in the dash pot will be'partially which position effective.-

Thedash pot pistons 108 and 122, andithe piston 140 maybe so fitted in their respective cylinders that on very slow opening ofthe throttle, the fuel in the various cylinders will" leak past the pistons substantially as rapidly as displaced thereby, the airvalve being ineffective under these conditions to;-liftthepiston 140 as previously described. I

Upward'movement of the air valve is lim- .ited by apin'138 extending across the auxtheupward movementof piston 140 Whenthe- 1 registers fully with the -orifice136.

duit 150 extending from the dash'potcylim' der 106 to a fuel distributingcanal -152,which c0 iliary cylinder in such position (.IS ftO stop piston is in a position'wh'erie the channel 137 The fuel pump compris'esa delivery'com communicates with three fuel delivery con-,

duits 154, one of which is shown in Fig, 1. Air passages 156, one of which appearsin.

dotted lines in Fig. 1, admit air tothe dis The piston 140 is adapted to be lifted-to the position where the passage 136 and channel 7 .137 are in exact registry whenthe throttle 100 is suddenly-opened relatively wide under theeifect of said valve A charge forming device for internal combustlon engines compr sing a mixingv said canalinto the primary mixture passages,

as fully set forth in-the above mentioned 7 application. r A secondary mixing chamber is associated with each outlet branch of the manifold, one

ofsuch mixing chambersbeing shown here-- in. Each mixing chamber comprises a Venturi tube 160 clamped between themanifold and the engine block a'nd positioned so that theoutletof-the' primary mixture conduit i associated therewitht'erminates at the point of greatest suction therein. These 'Venturi' tubes constitute no part of, the present inven t1on,but function in a manner fully set forth in the above-mentioned copending application;

.- allowed to escape: from thecylinden12O Whilethe form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, ltis to be understood that chamber, fuel and" air 'f inlets therefor, a

throttle controllingtheflowof mixture there- 1" from, an auxiliary air'passage, a valve controlling flow through saidpassage and oper-"v ated by suction effectiveon said valve, meanscontrolling :the r'novc l l of Said Valve and fluid'pressure operated means e'fiec'tive un,-'

der all operatingconditions, for regulating controlling means. v

chamber, fuel and air inlets therefor, a throt tle controlling. the flow of g I mixture therefrom, an auxiliary air passage,

a valve; controlling flow "through said passage, means for resistingthe opening movementof said valve, and

fluid pressure'operated'means effectivennder all operating conditions,- forregulating the resistance offered by'said resisting means to.

the movement'of the. air valve.

8; A charge formingdevice for internal- .COIIlbllStlOIl engines comprlsing a mixing chamber, fuel and :air: inlets therefor, a throttle controlling the flow of mixture therefrom, an auxilzaryair 'passage,'a valve con-trolling Vflow through saidpassage, a'idashipot'for combustion engines comprising afymixin g chamber," a fuel inlettherefor, amain airi valve controlling admission ofair thereto, a throttle, an auxiliary airpassage,'an-auxilioperation of the auxiliary air valve [and regulating;

ary air valve therein, means controlling the means operated by'the main airvalve for reg- 1 a 5. A charge formingdevice for internal- 7 combustion engine's comprising I a 1 mixingn ulating the action of saidcontrolling means. tributing canal 152 to form therein an emulsion of fuel and air which is 1forced from' chamber, a fuel inlet therefor, a. main air valve controlling admission of air thereto, a throttle, an auxiliary air passage, an auxiliary air valve therein, means resisting the opening movement of said auxiliary air valve and means operated by the main air valve for regulating the resistance of said resisting means.

6. A charge forming device for internal combustion engines comprising a mixing chamber, a fuel inlet therefor, a main air valve controlling admission of air thereto, a throttle, an auxiliary air passage, a suction operated air valve in said air passage, means retarding the opening of said valve on increase of engine suction, and means operated by the main air valve for varying the effectiveness of said retarding means.

7. A charge forming device for internal combustion engines comprising a mixing chamber, a fuel inlet therefor, a main air valve controlling admission of air thereto, a auxiliary air passage, a suction operated air valve in said air passage, means normally retarding the opening of said auxiliary air valve and means operated by the main air valve for rendering said retarding means ineffective on opening of the throttle under certain operating conditions.

8. A charge forming device for internal combustion engines comprising a mixing chamber, a fuel inlet therefor, a main air valve controlling admission of air thereto, a throttle, an auxiliary air passage, a suction operated air valve in said air passage, means normally retarding the opening of said auxiliary air valve, and means operated by the main air valve on opening movements of the throttle to reduce the resistance of said retarding means or render said means entirely ineffective.

9. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air supply passage, a valve controlling flow of air through such passage, means for resisting the opening movements of said valve and means efiective on all opening movements of the hrottle but operable independently thereof for variably controlling the resistances to opening movements of said valve in accordance with the speed at Which the throttle is opened.

10. A charge forming device for internal combustion engines comrising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air supply passage, a valve cont-rolling flow of air through such passage, means for resisting the opening movements of said valve, a. main air valve, and means operated by said mainair valve on opening movements of the throttle for variably controlling the resistance to opening movements of said auxiliary air valve in accordance With the speed at which the throttle is opened.

11. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air supply passage, a valve controlling flow of air through such passage, means normally resistin the opening of said auxiliary air valve, controlling means operative on rapid opening of the throttle but operable independently thereof to render said resisting means ineffective and on relatively slow opening of the throttle, to render said resisting means partially inefiective.

12. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto a throttle an auxiliar air suo l V 7 7 passage, a valve controlling flow of air through such passage, means normally resisting the opening of said auxiliary air valve, controlling means operable independently of the throttle but effective on rapid opening of the throttle to render said resisting means ineffective and on relativelyslow opening of the throttle to render said resisting means partially ineffective, said controlling means being inoperativeto render said resisting means either Wholly'or partially ineffective during very slow movements of the throttle.

13. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air supply passage, a valve controlling flow of air through such passage, means operable to retard the opening movements of said air valve, means for variably controlling the effectiveness of said retarding means, and means for operating said last named means when the throttle is opened but constructed so as to operate said controlling means independently of the movement of the throttle.

14. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air. supply passage, a valve controlling flow of air through such passage, means for resisting'the opening movements of the auxiliary air valve, a main air valve operated by engine suction, and means operated by said main air valve for varying the resistance of said resisting means in accordance with the variations in suction effective on the main air valve.

15. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a throttle, an auxiliary air supply passage, a valve controlling flow of air through such passage, means for resisting the opening movements of the auxiliary air it -'vjalve, a'jmain.-air valve operated by engine 2 suction, and means operated by the mam alr t v "valve for rendering said r'eslstlngmeans 1n- ,1 j

efiectivewhen thesucti'on operating the'main r 5 air valve ;is greatly increased. 1:16. A charge forming device: for internal "combustion engines comprising a mixingjf chamber, means for supplying fuel and air --there to, 'a throttle, an auxiliary fair supply" r passage, fal Valve controlling flow of air -jthroughsuch passage, means for resisting the openmg movements ofthel auxiliary air -valve, amain air Valve operated by engine" ..suction,; and means operatedby saidmain air valve for varying the resistance ofsaid v V p resisting-means in accordaIlCe With the 'vari- I ations in section eifective on the main air.

-va1;Ve,said means being rendered partially i I "inefiective when the suction operating the "z air valve isincreased-to a lesser degree. 7 17.' A.charge forming device for internal jcombus tion engines, comprising a plurality of mixing wchambers, means forsnpplying ,fuel and air thereto, a throttle controlling V i a 2 the flovvthrough all ofsaid mixingchambers, r an ai-rvalvecontrolling the admission of air- Z 7 3 ,to said mixing chambers;meansoperable to Y I retard: vthe Opening -moven1ents or. saidair valve; means forvariablycontrollingthe re a v sistanceof said retarding Emeans, means for @Yar-iably operating saidcontrolling means-in accordance with the speed at -Which-the v.

' ;throttle is operated, said operating'means j. g forthe controlling means being constructed l 85- to operate independently of the movement 5 ofthe throttle;

{18.A charge forming device comprisingl .ajplurality of secondary; mixing chambers,

yaepluralityof primary-carburetors supply- Q 40ing a primary; mixture of i 'uel and air to;

' said secondary mixing chambers, means supf-plyin'g fuel and air thereto, a throttle, an

i -auxiliaryair passage for supplying air to said for controlling the flow of; air through said vsecondary m xing chambers under certain I OPBIZLtIDgCOIldItIODS, anauxlliarya1r valve auxiliary air passage, means operable to re- Ztard the opening movements .of said'auxila r iary airval-ve, means for variably controlling 11. z the resistance ofsald retardingmeans, means i' or variably operating .sald controlling .means in accordance with the speed at which I ,7 4 .r thethrottle is operated, said operating means Y i for the controllingmeans being constructed' 7 j i t0 operate independently of the movement of the throttles a I s 4 Init estimony whereof I hereto aflix my signature. V

' D ELASE TINEF n i; r

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