US1855215A - Charge forming device - Google Patents

Description

April 26, 1932 F. E. AsELTlNE 1,855,215

CHARGE FORMING DEVICE Filed June '17; 1 929 I 5 i si rm r. Amann, or nanou, omo, Assxeu'on To mimo consonnes..

' 'or nanou,- onxo, a coneau-ron or umwancnaaes roannre mamen i I annua nea :ne 1v, im.' :um n. vf`

This invention relates to charge forming devices, more particularly to that type o chargeforming device which comprlses a pluralitl ofsecondary mixing chambers located adacent the engine intake ports, which are sup lied with a primar mixture of fuel 4 and air y a plurality of' rimary carburetorsassociated therewith an under certain operating conditions are supplied with additional are to be mixed with the primary mixture therein.

An example of a charge forming device of this character is disclosed in thecopend-4 ford Teeter, Serial No. 221,371, filed September 22, 1927.

The primary object of the present invention is to improve the means for supplying fuel andair in a device of this character, for the urpose of improving the mixture proportlonlng under certain operating conditions, ymore particularly for improving the mixture proportions during the acceleration period following opening movements of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings: Fig."1 is a vertical longitudinal section through a charge forming device according y to the present invention and an intake port with w ich it is associated.

Fig. 2 is a transverse vertical section on the llne 2-2 of Fig. Fig. 3 is a detail viefw chamber.

The device die :f f:

of the auxiliary fuei comprises a main air manifold 10 having three outlet branches, the

ing aplpllica'tion of Fred E. Aseltine and Wil" Vtween the fuel bowl middle branch 12 being shownherein. Each of these branches communicates 'withfone" of the intake ports 14 of vv'a multi-cylinderw; enf'lne. These outletbranches areeah `provided'with an attaching flange lfforsecurw v ing the manifold tothe englne 'block'in the usual manner. Ad'acent 'the finletj of vthe manifold is provide 'a flange 18m-which the main carburetor unitis adapted'to be attached,asshown in Fi .1; am The carburetor unit com risesfa main housin 20 having an 'attac 'ng flange l22 adapte to be secured to flange 18vby screws I 24. The air inlet coupling28 is secured in position to register with an opening' in` the yupper wall of the housing 20 in any suitable way and an air cleanerV may be connected thereto if desired. A casting` 30, in `which the passages conducting'fuel :fromV the fuelA bowl-to the nozzles are formed, is secured by screws to the bottom wallfof housing-120, .and asheet metal fuel bowl32 ischeld tight' .against an annular-shouldenflon'said hous.-

ing b any suitable means..`f Fuel is con ducte from a main sourcefjof supply .to the fuel bowl through. a conduit not -shown here in and the How of fuel 'tothebowl is ;co`n-` trolled by a Boat 36, operating jinthensLial manner to maintain aA substantially constant level of fuel therein... y; 2 s@ Fuel Hows from bowl 3 u; n

primary fuel noz'zles onegoffiwhich; islios cated in each of the primary mixing chain:

bers 40, the construction ai@ wh' isi-tried?? described hereinafter. T heyfue iduitfbcf Omuri s' a vertical fuel passageu42 its upper end With-a 44, which connects with 38 through orifices 4.6.` Fu f ,A l the fuel bowl to passage i2 M through a fixed metlig I high speeds additionall through an orifice 50, con in the manner set forth ticned application.

Fuel is lifted fr'ommtli' the above described fuelfp'a 38 to the mixingchmbe therein. Closing movements (if the thrc-ttie r ma in mixing chamber suction,

which permit the fuel column to drop y ,f toa temporary fuel starving @filas w. 4 r s were provided to rm. l ose a check valve54 d chamber 56 at the and 44, and on re-l Iber suction seats vvon preventing down- Waxdlowofthefnel. y

, 1 a fud'mzzle is provided with Saa uw: tu. the topof the nozzle a w.: x ry fuel nutletfcomprisingtwo 60 and 62 in 'thewertical wall ofthe near the of the mixing chamber, .At relatively lajlghspeeds the mixing fr wir on is enough lto lift fuel from the main outlet as well as from orices 60 and At idling, or low speed operation however, the suction is sufhcient no lift fuel only to some point between the top of the nozzle and orifices 60 and 62, fuel 'D romt (milices b y action of gravi nozzle is provided with a restrictp. metering orifice 63.` The primary mixing chambers comprise the enlarged anef primary mixture passages 64, are parallel to .each other and close tog as :indicated in lthe drawings. When caxlmretcr is attached to the manifold, @these mi register with conduits which Ienwey the primary mixture to the secondary mfxing= nach: as .fully disclosed in the co- ;pending application referred to. Restric- "66 separate the rimary mixing chamlbers from remainder of the mixture pasi throttle rvalve 68, which extends the primary mixture passages, concommunicates with a tube in manifold branch 12, which 72, fixed conveys chamber in that .branch of the maniy all the, .air entering the carlows through the coupling 28, conby a main air valve 7 4, normally held a seat 76 by a spring 78 received befrom a e 82 slidably mounted on a statemxy guidesleeve iti, fixed in the housing w td i" r; as a guide sleeve for the stem to the air valve 'is secured.

".'1 fa.. 1t1s\.-..; t to choke the carburetor facilitate 4the flange is adapted to by means not shown herein but fully .wir bed in the above mentioned aplmlilthe upper end of the sleeve 82 W the vnlvc'to hold it closed. Suffi- -iow therethrough and is providedl thepnmarymixture to the secondary imam ille valve and a flange projecting cient air to carry thelstarting the nozzles to the intake ports is admitted through an elongated slot formed in a plate 92 secured to the housing 2O as shown in y 'lha couplin 28 supplies air directly to a main air cham r 94 from which it flows to the primary mixture; passages ythrough an orilice 96 in thejiloor ofthe airchamber and to the secondary mixing chambers through a I passage 98, which connects with the inletof thel manifold4 10'. /A Imanually operable 4throttle 100', secured'to a shaft 102 andoperated bythe primary throttle operating mechanism 1n a manner hereinafter briefly vde- 'opening movement, and also to prevent fluttering of the valve. The retarding means comprises a dashpot comprising a cylinder 106 formed in the casting 30, and a piston 108 clamped between a flange 110 on a coupling 112 secured to the lower end of the airv valve stem and a nut 114 screwed on the coupling. A check valve (not shown) may be provided in the bottom of the dashpot to admit fuel to the cylinder on upward movement vof the piston and prevent escape of fuelfrom the cylinder on downward movement of the piston. This dashpot is of conventional form and the structural details constitute no part of the present invention.

In order to facilitate understanding of the operation of this invention the mode of operation of the throttles will now be very briefly described. As. above stated the primary throttle operating mechanism is adapted to operate the air throttle 102 but a lost motion connection is provided in the operating connections which permits an initial opening movement of the primary throttle withoutaccompanying movement of the air throttle. after which the throttles move simultaneously. Preferably the construction is such that the primary throttle is permitted to open independently of the main throttle until the engine is running at aspeed corresponding approximately to a vehicular speed of 20-25 miles per hour on a level.

It has been found that the dashpot, in order to enrich the mixture suliicientlyy for satisfactory acceleration on all opening movements of the throttle temporarily must retard the ail'- valve so much that under some conditions the suction at the nozzles builds .291359 iaggsuchg, a? degree:that the mixture tem- '-tborichzresulting in ,loadu ,l example of condi- *ersuvhich .-,thesdashpot iseffective produc" tooirichjamixture to be suitable, ay assumedLthati the throttle is opened from aijrelativelyifelosed `position to a rela- D tiveelyswide fopen: positionV as frequently oc-` {tight joint being provided between the cham- Eber and its top 122. kThe latter is provided with an'upstanding lug 124 adapted to be atl `itached, to. thecasting 30 by a screw 126. If desired the chamber '.120 could be formed in thecastin'g 30, integral therewith. Screwed -into the-bottom `ofthe chamber 120 or ,conenacted therewithvin ,any other suitable man- :fneriis afpipe`f128,y the other end of which :lis .connected :to fthe, fuel supply passage be- ;@tweenjthe valveP52 andthe vertical passage 442as shownfinyllig. 12.- -A union or other .suitable Vcouplingmeans may beprovided in :thepipe-128to1.facilitate 'assembly of the parts. `A `suction conduit 130, which may be formedas onen piece or in two parts joined by the unionf132-, is connected at one'end to lthe upper ,partof the chamber 120, and the other fend projects through the-walll of the. )housing into the main air chamber 94. A nipplef134 ,is screwed -intojthe pipe 130 to ladmitair thereto, for-'the'purpose of controllling .the suctioncoinmunicated by such pipe Eto :the :chambers-120.1 2

The device yoperates-i11- substantially 'the followingfma-nner. .y-Itfmay be assumed that thegvehiclerisy beinigfoperated at a speed of 1'5-,20 mileszjfperhour.@If the throttles are .opened `further to increaseY the speed relativev"ly rslightly, tfonv example :to -35 miles per vboum-.the lsucti'onf-ati:the'fuel vnozzles is increaSeddungthetemporary retardation of the opening movement of the air valve, so as v,to increase'thefuelllwtolenrich the mixturev ato the.extentfrnecessaryfor smooth accelerationfliut'f` the'. suction'l does 'not increase suiliciently :tofform-'too' 'richfaV mixture. If, however-.,thethrotftle's are-*opened from a relative- .closedpoeitinf; eitherfwhen running fast 'at the end of a coast or when running slowly under load, to a relatively wide open position,

the suction at the fuel nozzles is builtvup so greatly while the dashpotfresists the-opening I of the air valve that there is a very great increase in suction at thel fuel nozzles which' would result-in too much-enrichment of themixture causing loadingl and irregular engine operation. l The suction of the air chamber 94 is communicated to the chamber v120 and tends to draw fuel from the fuel supply passage 4leading to the nozzles, through the pipe 128 into the chamber 120 and if effective todraw fuel from the said passagewill reduce the amount of fuel Whichwould otherwise be supplied to the nozzles.- At any fixed throttle posi-- tion when the air valve is in a condition of balance the suction communicated to the chamber 120 .is not sufficient to draw fuel from the passage 42 to such. chamber. In fact, due to the admission of air through the nipple 134 the pressure in the suction passage and chamber 120 is little-less than atmospheric .under `those conditions. Moreover, the `supply of air through the nipple 134 is such that the suction within the suction passage and chamber 120 is not increased suiicientlyon opening of the throttle under. the conditions first described above to draw fuel from the passage 42, because as above set forth, the mixture enrichment is not too great under such. operating conditions. v 4

Then the throttle is opened from nearly closed positionv to relatively wide open position, however, the suction in the air chamber 94 increases enough to createA sufficient suction in chamber 120 to draw fuel into such chamberfrom the passage 42, notwithstanding the admission of air through the vent. This will cause the nozzles to deliver .a less amou'nt of fuel than would otherwise have been supplied as aresult of the temporary increase in suction at the nozzles whereby a mixture of proper proportions is supplied. y

The fuel drawn into the chamber 120 in the manner above described is retained insaid chamber only so long' as the suctioneifec# ,tive in said chamber is suiiicient to support a column o f fuel extending that much'above the normal fuel level. As soon as the suction becomes insufiicient to support such a column of fuel, the fuel in said chamber flows back into the fuel passage 42, slightly auginenting the fuel flow from the nozzle until v the column of fuel in the conduit 128 falls to the ipoint where it is balanced by the suction e ective on said column. It will be clear prevent the mixture being enriched too much at any one instant and is also effective to prothat the device above described is'eifective to'f125 long the total period of mixture enrichment. j This action is obviously beneficial when thev throttle is 'opq'enedthrough relatively'great" V operative on certain opening movements of the throttle to restrict the How of fuel from said inlet, said means comprising a suction conduit extending from the air supply chamber to the fuel passage leading to said fuel inlet.

8. A charge forming device for internal combustion engines comprising a mixture passage, a fuel inlet therefor, an air chamber for supplying air to said mixture passage, a throttle, a fuel supply passage leading to said fuel inlet, a throttle, means op.- erative on opening movem'ents of said throt tle for increasing the iow from said fuel inlet to enrich the mixture for acceleration and means for modifying the effect of said last mentioned means on certain opening movements of the throttle, and means oomprising a suction passage connecting the fuel supply passage with the intake passage at a point anterior to the throttle.v

9.'.A charge forming device for internal combustion, engines comprising a mixture passage, a fuel reservoir, a fuel inlet in said mixture passage, a fuel supply passage connecting said inlet with the fuel reservoir, a throttle, an air chamber for supplying air to said mixture passage, means operative on opening movements of the*l throttle to increase the flow from said fuel inlet in order to enrich the mixture during the acceleration period; an auxiliary fuel chamber, a consupply passage, and` means effective on certain opening movements ofthe throttle to effect a flow of fuel yfrom the lsaid 'fuel passage to said auxiliary chamber. 1

10. A charge forming device for internal combustion engines comprising a pluralityA of secondary mixing chambers, a plurality of primary mixing chambers supplying a rimary mixture of fuel and air thereto, fuel inlets therefor, an air chamber supplying air to all of the primary and secondary mixing chambers, a throttle regulating the flow from all of said primary mixing chambers, means v operative on opening movements of the throt' ,l tle for increasing the flow from said fuel of secondary mixingchambers, a pluralityof' primary mixin chambers supplying a rimary mixture o fuel and air thereto, fuel inlets for supplying fuel to said primary mixing chambers, a fuel reservoir,l a fuel supply passa connecting said fuel reservoir with said uel inlets, a throttle, an air chamber @for supplying air to al1 of said primary and secon ary mixing chambers, means operative on opening movements of the throttle to increase the flow from said fuel inlets in order to enrich the mixture during the ac celeration period and means effective on certain o ening movements of the throttle to draw uel from said passage whereby the de-` gree of'mixtur'e enrichment is reduced.

In testimony whereof I hereto aiiix my signature.

FRED E. ASELTINE.

' duit connecting said chamber with the fuel. 'l

iso

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