US1858848A - Charge forming device - Google Patents

Description

May 17, 1932. F. E. ASELTINE CHARGE FORMING DEVICE Filed Nov. 2, 1929 2 Sheets-Sheet 1 v May 17, 1932. F. E. ASELTINE CHARGE FORMING DEVICE Filed Nov. 2, 1929 2 Sheets-Sheet 2 I E'PJZ Aka/i125 v'wshm 05%;-

Patented. May 17, 1932 UNITED STA TES PATENT OFFICE ram) E. ASELTINE, or DAYTON, OHIO, assrenonao DELCO raonuors CORPORATTON,

OF DAYTON, OHIO, A CORPORATION .OF DELAWARE CHARGE FORMING nnvron Application filed November 2, 1929. Serial No. 404,323.

This inventionrelates to charge forming devices for internal combustion engines and most particularly to that type of charge sition.

forming devices which comprisesa plurality of primary carburetors each of which is adapted to deliver a primary mixture offuel and air to one ofa plurality of secondary carburetors located adjacent the engine intake ports and in which additional air is mixed with the primary mixturebefore the latter enters the engine cylinders under certain operating conditions.

An example of a charge forming device of this type is disclosed in the application of Fred E. Aseltine, Wilford H. Teeter, Carl H. Kindl and F. D. F unston, Serial Number 370,179, filed May 13, 1929.

It is the general object of the present invention to provide" means for securing im- .substantially immediately after the throttle has been moved to substantially closed po- This general object is accomplished according to the present invention by the provision of means for supplying additional fuel to the primary mixture passages during the closing movement of the throttle. This fuel is drawn into the mixture passages as the throttle is closed .and since the velocity of flow through said passages is very slow when the throttle is substantially closed it will require an appreciable time for such fuel to be drawn out of the mixture passages, and most of it will remain in said passages between the point where it is admitted thereto and the outlet ends thereof until the throttle is again opened so that'it is then immediately available and is carried -into the engine intake ports practically simultaneously. with the opening of the throttle. 7

Further, objects and advantages of the present invention will be apparent from the following'description, reference being had to nism.

In the drawings: Fig. 1 is a vertical longitudinal section through a charge forming device embodying the present invention.

Fig. 2 is a side elevation of the carburetor unit forming part of the charge forming device, partly broken away to show certain parts in section and having a .cover plate removed to show the valve operating mecha- Fig. 3 is 'a rear elevation of the carburetor unit partly in section.

Figs. 4: and 5 are horizontal sections on the I lines 44 and 55 of Fig. I.

The device'comprises a main air manifold 10 having three outlet branches, the middle these branches communicates with one of the ports of a multicylinder en ine and each is provided with an attaching ange 14 which is adapted to be secured to the engine block in the usual way, while adjacent the inlet of the manifold is a flange 16 to which the main carburetor unit, hereinafter described, is adapted to be secured, as shown in Fig. 1.-

.branch 12, being shown herein. Each of,

The main carburetor unit comprises a main housing 18 in the form of a single casting hav ng a flange 20 adapted, to be secured to the flange 16 by screws 22. A valve controlled air inlet coupling 24 is secured in position in an opening in the top of the housing 18 by screws 26, or in any other suitable manner. A casting 28, having certain fuel passages formed therein, is secured by screws 30 to the bottom of the main housing and a sheet metal fuel bowl 32 is held tight agamst an annular shoulder 34 on the bottom of the main housing by a screw 36 screwed into the I casting 28, suitable gaskets being provided wherever necessary to prevent leakage of the fuel. A fuel conduit, which is not shown herein,.supplies fuel to'the fuel bowl and a float 38 operates to maintaina substantially constant level of fuelin the bowl in the usual manner.

A plurality of angular primary mixture passages, indicated in their entirety by the reference character 40'and hereinafter more fully described, are provided in the lower part of the main housing. Communicating the fuel will flow from with the vertical portion of these mixture passages through orifices 42 are three chamers 44 which, for convenience, are desi nated fuel supply chambers. Fuel is a mitted directly tothese chambers by nozzles 46 and is mixed therein with a small quantity of air admitted thereto by a slot 48, formed in a partition separating the fuel supply chambers from a main air chamber to be more fully described.- later. This mixture of fuel and air flows from the fuel supply chambers through the orifices 42 to the primary mixture passages. 7

Fuel is supplied to the nozzles 46 through a vertical fuel passage 50 formed in the casting 28 and communicating at its upper end with a horizontal channel 52 which communicates directly with all of the nozzles-46, while at its lower end the passage 50 connects with a horizontal passage 54 which, in turn, communicates with the interior of the float bowl 32 and is provided with a calibrated metering plug 56 having a fixed orifice therein, as shown in Figs. 3 and 5. each of the fuel nozzles 46 is provided with a restricted metering orifice 58 as illustrated in Fig. 1.

Each nozzle is provided with a main fuel outlet 60 in its top and a secondary fuel outlet comprising two orifices .62 and 64 formed in the vertical wall of the nozzle adjacent the bottom of the fuel supply chamber. At

relatively high speeds the'suction within the fuel sup ly chambers is sufficient to effect a flow of uel from the main orifice 60 in the top of each of the nozzles, but during idling, or low speed operation under load, the suction communicated to the nozzles is suflicient to lift the fuel only to some point intermediate the main fuel inlet 60 and the secondary fuel feeding orifices 62 and 64, at which time the latter by the action of gravity.

The prlmary mixture passages-are controlled by a single throttle valve 66 which extends across all of the assages, is provided with grooves 68 which register with said passages, and is operated by means more fully described later. The primary mixture passa es register with conduits for conveymg t e primary mixture to the secondary mixing chambers. when the device is assembled. These conduits comprise tubes cast 1n posltlon in the manifold during the casting of the latter as fully shown and described in' the above copendmg application. Only the tube 69 for conveying primary mixture to the secondary mixing chamber formed in the middle branch of the manifold is shownherein, sincethese tubes, of themselves, form no part of the present invention and their specific construction is entirely immaterial thereto,

All of the fuel supply chambers 44 communieate with acha'mber 70 which may be termed a primary air chamber. The champassages by a vertical partition 76, which is a formed as an integral part of the main housing and ported. The fuel supply chambers 44 are separated from each other by vertical partitions 7 8 which arealso integral with the main housing.

All of the air supplied to the carburetor is admitted through the air inlet coupling 24 and is controlled by a valve 80 normally held against its seat 82 by a spring 84 received between the valve and a flange 86 projecting from a sleeve 88 slidably mounted on a fixed sleeve 90 which guides the stem 92 to which the air valve is secured. Under normal operating conditions the sleeve 88 occupies the osition shown in Fig. 1, but may be lifted y the choke lever 94 until it enga es the valve 80 to hold said valve closed for the purpose of aiding in starting the engine. The choke mechanism forms no part of the present invention and will not be more fully described herein, but is completely described in the above mentioned earlier application.

The valve 80 admits air directly to the main air chamber 74, which supplies air to the primary air chamber as above set forth, and also to the secondary mixing chambers in the manifold by means of a secondary air passage 96, controlled by a manually operable valve 98, secured to a shaft 100 rotatably mounted in the main housing, and a suction operated valve 102, secured to a shaft 104 which is also rotatably mounted in the housing 18. The operating mechanism for these valves will be described hereinafter. In addition to the air supplied to the chamber 70 and that supplied to the secondary mixing chambers as above disclosed, the main air chamber also communicates directly with the vertical portions of the primary mixture passage and supplies air thereto.

The slot 48 admitting air to the fuel supply chambers is considerably larger than the total area of the three orifices 42 which connect the fuel chambers with the primary mixture passages. Becaus of this difference in area of the air inlet and outlet to the fuel supply'chambers, it is obvious that the. flow of air through these chambers, must necessarily be at low velocity under all operating conditions and at all engine speeds. For this reason there is substantially no velocity head created at the fuel nozzles under any operating conditions, the reason being more fully set forth in the earlier applications above referred to,;and the suction which is effective to cause a flow of fuel from the nozzles is substantially the static suction on which the partition 72 is sup-,

of the air chamber by the primary throttle after the primary main air valve spring.

During operation at all engine speeds be eel low a certain predetermined sp for example, that correspondin the mixture conveyed through the primary mixture conduits is suiiicient to provide the l proper quantity of fuel charge and is 'con-.

veyed to the engine without mixture with additional air in the secondary mixing chambers. At higher engine eeds than this, however, the valves contr l hng thesecondary air passage are opened torincrease the quantity of mixture supplied to the engine. Themanually operable valve 98 is operated throttle has made a certain amount of independent movement and the valve 102 is opened by the en-"ne suction substantially simultaneouslywit the opening of the valve 98. To operate these valves an operating plate 106 is secured to one end of the throttle,

in the manner disclosed in the above ap' lication, and is pivotally connected by a link 108 to an arm 110 which is secured to the shaft 100 of the valve '98. normally held in the position shown in Fig. 2 with the valves, 98. closed and during the first partof the opening movement of the throttle the point of connection of thelink 108 with the plate 106 moves substantially in the are of a; circle, of-connection between the link 108 and the arm 110, so that the arm 110remains stationary. After this amount of movement of the primary throttle further movement thereof will move the arm'1'10 and open the valve 98. --Because of a slight tendency of the parts to bind, the link 108 is connected to the arm 110 by means of a in. 112 projecting from saidarm and exten in is normally y means-of a ap lication.

' enever the 'valve 98is 'opened', the en 'suction opens the valve 102 "and the gins open ng movement'of this'valve is" retarded;

by a dashpot comprising afcylinderand cooperating piston (not shown 1 herein) but which is connected by a link 110 to an arm 115 secured to'oneend of the shaftf104. On closp lhvlotally mounted on theoperating plate 106.

rejecting from 'sarm engages apin'120. p

to effect return link 116 and the arm is move of the suction operated valve'to'normal posi-i tionby the spring 122,-onejend of whichjis connected to an ear 124 prqjectmg from the arm 118 while the other end is secured to the mainhousing as shown in Fig. 2.- This valve pp'erating mechanism 'constitutes nof art of e present invention, and: for amore etailed determined by the to a vehicular speed of 20-25 miles per our on the level,-

The parts are the center of which is the point ing" through a short slot.

' (not shown) in the link. The held in one end of the slot spring 114 as fully described the earlier.

meeting with a vertial to 'a fuelwell 152 formed mg movements of the-valve"88'thesuction 1 operated valve, 102 is closed. by'an' arm 118] sage 154 communicates with'the oiiter description thereof reference may be had to the application herein referred to in which the .valve operating mechanism is the same as disclosed herein. 1

. On opening movement of the throttle, suctionv in the main air chamber is increased and the main air valve is opened to permit an increased flow of air past the valve. It

has been found necessary to retard the openand the dashpot may be of any conventional form so far as the present invention is concernecl.

to rovid e tem orarily, a somewhat enric ed m xture in or er to prop erlyjoperate the engine during the accelera- 7; 0n opening of the throttle it has also been found necessar tion period for reasons which are well known to those skilled in this art. For this a fuel ump has beenprovided whic is operated y the primary throttle and comprises closed at its lower end by a plate 136 secured by screws 138 to the; bottom of said casting:

pump piston 140 .is received within the cylinder and is pivotally connected to an operating link or rod 142, pivot'ally connected by pin-144 to the operating plate 106, which issecured as hereinbefore escribed to the primary throttle; Onopening movements of the'throttle the member 106 is moved in a urpose 'a cylinder 134 formed in the casting 28 and Y clockwise direction and thepiston 140 is depressed, 'while on' closing movements of the throttle the piston is returned to the position shown in Fig. 2by a spring 146,rec eived in- ,tjhe cylinder- 134 betw the Piston. and the 'plat'e 138. a

v The fuel delivery passage from the pump comprisesjahorihontal passage Z1148 commu g' in the upperpalft passage. 150.1leading of thebas'ting 28: A m-slay of horizontal pasages' 154 connect t e bottom of this .well

with v rflow amber,1'56which iscon."

nected fat its n perendfbyanorifice 158fiivith' F 7 an auxiliary uel reservoirF160, the function ofwhich is more fully later-1. Th f middle'passage 154- communicates "directly I 'with the middle one of.thl everticallgasg' 7 sages .162, "formed ingthe 'jfcas'ting'j 1 28.1 i middale passage 162' registers .with "a co'rreI P p e t supp middle mixture passages 40. The" u'te as sages .162, which connect with horizontal Pas ge .in the war ofgthehonsi 18, Whic is g in the casting 28.

56 valve 178 is opened by moved toward closed p0 ition,

the piston rod 142 and. is of such its ' a chamber 160 while a part of the fuel delivered to the well 152 will pass through the various delivery passages into the primary mixture passages to enrich the mixture temporarily during the acceleration period.

A passage 168 as shown in Fig. 4 admits air -to the top of the fuel reservoir 160 and serves the doub e purpose of venting said reservoir and supplying air to the fuel which passes into the primary mixture passages so that an emulsion of fuel and air is delivered thereto. By admitting air in this manner, the suction communicated to the fuel delivery passage is never sufficient to draw fuel from the pump cylinder and nofuel is supplied to the mixture passages by passages 162 except on the downward stroke of the pump piston.

The auxiliary reservoir 160 is adapted to supply fuel to the primary mixture passages during closing movements of the throttle and for this purpose a delivery passa e 170 is provided, which communicates wit the reservoir at the bottom and with a bore 172 formed A plug 174 is screwed into this bore and is provided with a central passage'176 whichis normally closed by a valve 178 held in its closed position by. a spring 180 above the valve as shown in ig. 1. The plug 174 is also provided with lateral orifices 182 which communicate with the central passage 176 and with an angular passage 184, which conducts fuel from the auxil iary reservoir 160 back into the well 152 whenever the valve 178 is opened, whereby such fuel may be drawn into the primary-mixture passages through the passages 1 an arm 186 carried by the piston rod 142 on the return of the piston to normal position when the. throttle is the arm being adapted to engage the valve when the throttle is nearly closed. The arm 186 is secured bv rivets or in any other desirable manner to shape that ree end is immediately under the stem I of the valve 17 8.-

The' function and purpose of this device is substantially as follows: It has been found by experiment that where a pump such as that above described is used, there are certain operating conditions under which the pum does not supply fuel to the intake ports Sn 7 'ficiently rapidl ends of the fuel deliv It will and the engine by 62. The

' ticularly to satisfactorily o erate the engine, and or a very brief period t e engine may actually miss firing. An example of such operating conditions is on opening of the throttle to accelerate the speed 'fol lowing substantially immediately the closing of the throttle. For instance, if the driver of the vehicle on which the device is used removes his foot from the accelerator edal and applies the brake, the primary tlirottleis closed automatically and the vehicle slowed down. The fuel mixture in-the primary passages between the throttle and the engine is swept out of the'mixture conduits and into the intake ports under these conditions 'so that only a very small quantity of fuel remains in the conduits the time the throttle can be again opened. Then if the throttle be opened to increase the vehicular speed there would be a brief interval during which the engine will not receive suflicient fuel to operate properly.. It is the purpose of-the present invention to supply additionalrfuel o the mixture passages through thepassages 162 as the throttle is closed. This additional fuel is drawn into the passages between the throttle and the engine ports as the engine is slowing down and before the throttle, is again opened, and sincethe rate of flow through the conduits is relative y slow when the throttle is closed most of t is fuel will remain inthe conduits until the throttle is again opened. Then when the throttle is opened, this additional fuel is carried into the portsand by the time such fuel has been drawn out of the passages, the additional will not be an interval in which the mixture is too lean.

The secondary mixin chambers may consist of any form of device for straightenin and accelerating .the flow of air past theen s of the primary mixture conduits and may be of the type shown in the earlier applications above referred to.

It will be noted that for convenience this invention has been incorporated in a device having the same general construction as dis-- closed in application Serial Number 370,179

but the present invention is in no way parrelated to that specific device and may be incorporated inman y other devices of this general character.

.lVhile the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms mi ht be adopted,-allcoming within the scope 0 follow. What is claimed is. as follows:

. 1. A charge forming device for internal combustion engines com risin amixture passage, means for supp ying l and air the claims which between the throttle thereto, a throttle, and means for supplying additional fuel to the mixture passage on closing movement of the throttle.

2. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, and means operated'by the throttle for supplying additional fuel to the-mixture passage on closing movements of the throttle.

3. A charge forming device for internal combustion engines comprising a mixture passage, an air inlet therefor, a main fuel "inlet therefor, a secondary fuel inlet for said mixture passage, a throttle, and means for causing a flow of fuel from said secondary fuel inlet enclosing movement of the throt:

- combustion engines comprising a mixture tle.

4. A charge forming device for internal combustion engines comprising a mixture passage, an air inlet therefor, a main fuel inlet therefor, a normally ineifective secondary fuel inlet, a throttle, and means for rendering said secondary fuel inlet effective to supply fuel to the mixture passage on closing movement of the throttle.

5. A charge forming device for internal i said secondary fuel inlet on closing movements of said throttle. 7. A charge forming device for internal combustion engines comprising a mixture assage, an air'inlet therefor, a main fuel inlet therefor, a secondary fuel inlet therefor ineffective under alloperating conditions without movement of the throttle, and means operated by the throttle for rendering said secondary fuel inlet effective to supply fuel to the mixture passage on opening or closmg movements of the throttle.

V 8. A charge forming device for internal .combustionengines comprising a mixture passage,- fuel and air inlets therefor, a throttle, a pump operated by the throttle forsupplying additional fuel to the mixture passage on opening movements ofthe-throttle and means operated by the pump for supplying additional fuel to the mixture passage on.

closing movements of the throttle.

9. A charge forming device for internal combustion engines .comprising a mixture passage, fuel and air inlets therefor, a throtadditional fuel to the mixture tle, a pump operable on openin movements of the throttle to supply additional fuel to the mixturepassage durin the acceleration period and meansoperate by the pump onclosing movements of the throttle to suppil'y passage on eceleration.

10. A charge forming device for internal combustion engines comprising a mixture passage, fuel and air inlets therefor, a throttle, a fuel reservoir for supplying additional fuel to the mixture passage and adapted to be filled with fuel on opening movements of the throttle, and means operable enclosing movements of the throttle for rendering said reservoir effective to supply ture passage.

11. A charge forming device for internal combustion engines comprising a mixture passage, fuel and air inlets therefor, a throttle,a fuel reservoir for supplying additional fuel to the mixture passage and adapted to. be filled with fuel on opening movements of the throttle, a valve normally preventing a v flow of fuel from the reservoir to the mixfuel to the mixture passage and means operable on closing movements of the throttle for operating said valve. c e

12. A charge forming device for internal combustion engines comprising a mixture passage, fuel and air inlets therefor, a throttle, a fuel reservoir, a pump operated on opening movements of the throttle and adapted to fill said reservoir with fuel, and means operated by said pump on closing movements of the throttle for rendering said reservoir effective to supply fuel to the mixture passage.

13. combustion engines comprising a mixture passage, fuel and air inlets therefor, a throt- A charge forming device forinternal "1 O5 tle, a fuel reservoir adapted ,to supply additional fuel to the mixture passage, a valve controlling the flow of fuel from said reservoir, a pump piston operable to simultaneously supply additional fuel to the mixture passage and tofill said reservoir with fuel on its pumpingstroke, and means carried by 1 said pump piston and adapted to operate said piston is returned to normal I valve when the position.

14. A combustion :engines comprising a mixture passage, fuel and'air inlets therefor, an accelerator .well adapted to supply fuel to the charge forming device for internal mixture passage on'opemng movement of the throttle, an auxiliary fuel reservoir for supplying additional fuel to the mixture passage, said reservoir communicating with the accelerator well and adapted to receive fuel f therefrom when saidwell'is supplied fuel .to said well fuel, means for supplying th th I and on opening movement- 0 means for rendering said reservoirefiective to supply fuel tothe mixture passage on closing movement of the throttle.

- 153; A charge forming device for internal com'bhstion engines comprising a mixture passage, fuel and 'air inlets therefor, an ac-. celerator-well adapted to supply fuel to the mixture passage on opening movementof the throttle, an auxiliary fuel reservoir for passage,

. movement of the throttle,

hug the flow through said passage, means sage,

supplying additional fuel to the mixture passai reservoir'communicating with the accelerator well andadapted to receive fuel therefrom when said well is supplied with fuel, a fuel pump for supplying uel to the well on opening movement ofthe throttle and means operated bysaid pump for rendering said reservoir efiective to supply fuel to the mixture passage on closing movement of the throttle.

16. A charge forming device for internal I combustion engines comprising a mixture fuel and air inlets therefor, an accelerator well adapted to supply fuel-to the mixture passage on opening movement of the throttle, an auxiliary fuel reservoir for sup-. plying additional fuel to the mixture passage, said reservoir communicating with the accelerator well and adapted to receive fuel therefrom when saidfwell is supplied with fuel, 'a, fuel pump operated by the throttle for-supplying fuel to the well on opening and means for causin g a flow. of fuel from said reservoir through said passage to the accelerator well onv closing movements of the throttle. I

17. A charge forming device for internal combustion engines comprising amixture passage, fuel and .air inletstherefor, an accelerator. well adapted to supply fuel to the 7 mixture passage on opening movement of the throttle, an auxiliary fuel reservoir for supplying'additional fuel to the mixture pasv sage, said reservoir communicating with the accelerator well and adapted to receive fuel therefrom when said well is supplied with fuel, a fuel passage connecting the accelerator well and auxiliary reservoir, a valve controlsuppl 'ng fuel to said well on 0 ma mover n ent's of the throttle, and means fir 0 crating said valve on closing movements of said throttle.

H 18. 'A charge forming device for internal combustion engines comprising a primary mixture passage, a secondary mixing chamber into which said primary mixture passage delivers a primary mixture of fuel and air, fuel and air inlets therefor, a prima throttle controlling the flow through sai prima mixture passage, means operated b the 1'!- mar throttle for supplying additional uel to t e primary mixture passage on opening vto supply additional fuel to said mixture pass sages. I v

20. A charge forming device for internal combustion engines comprising a mixture passage, fuel and air, inlents therefor, a throttle, a fuel reservoir adapted'to supply additional fuel to the mixture passage, a

pump operated on opening movements of the throttle, a valve controlling the flow of fuel from the reservoir to the mixture passage, andmeans operated by said ump on closing movements of the throttle f r opening said valve.

21. A charge forming device for internal combustion engines com rising a mixing passage, fuel and air inlets therefor, a-

throttle, a fuel reservoir, a pump piston operable to simultaneously supplg additional fuel to the mixture passage an to fill said reservoir with fuel on its pumping stroke and operable on its return to normal position to render said reservoir efiective to supply fuel to themixture passage.

In testimony whereof I hereto aflix my signature.

FRED E. ASELTINE.

for

Ill

movements of said throttle, and means operated on closing movements of the-throttle to supply additional fuel to the primary mixture passage during deceleration.

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