US2038157A - Charge forming device - Google Patents

Description

A ril 21, 1936. F. E. ASELTINE ET AL CHARGE FORMING DEVICE Filed Sept. 22,192? 5 Sheets-Sheet 1 an W: Q

21, 1936. F. E. ASELTINE ET AL CHARGE FORMING DEVICE Filed Sept. 22

, 1927 5 Sheets-Sheet. 2

' 1936. F. E. ASELTINE ET AL CHARGE FORMING DEVICE F. E. ASELTINE ET AL CHARGE FORMING DEVICE Filed'Sept. 22, 1927 5 Sheets-Sheet 4 k um April 21, 1936.

F. E. ASELTINE El l.

CHARGE FORMING DEVICE 5 Sheets-Sheet 5 Filed Sept. 22, 1927 CML A JGQL a es/M Patented Apr. 21, 1936 UNITED STATES 2,038,157 CHARGE roamno DEVICE 'Fred E. Aseltine, Carl B. Kindi, and Wilfordll.

-Teeter,'Dayton, Ohio, assignors, by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 22, 1927, SeriaLNo. 221,373

40 Claims.

ture from a pipe connected with one of the pri-- mary carburetors and receiving air when required through one branch of an air manifold which supplies air to all of the secondary car- 15 buretors. The primary'carburetors receive their liquid fuel from a common fuel bowl in which the level is controlled by a float valve. Examples of carburetors of this nature are illustrated in the patents of W. H. Teeter, No. 1,819,526, and Fred E. Aseltine and W. H. Teeter, No;'-'-l,8.19,495. In the charge forming devices disclosed in these applications, a plurality of pricarburetors are provided, one for each intake port. The fuel mixture from such primary carburetors is conveyed to the secondary mixing chambers located adjacent the various engine intake ports where it' is mixed with additional air. In 'these devices, the throttling of the engine is effected by a single primary throttle which controls all the primary carburetors, and a single main throttle controlling the air flow through the main air manifold. These throttlesare operated from a common operating mechanism which is so arranged that the primary throttle controls the 3 5 quantity of mixture passing to the engine at speeds up to a vehicular speed of 20-25 milesper hour, after which the main air throttle begins to open and becomes the main controlling element regulating the mixture outflow.

t -I'he general objects of the devices disclosed in thematents above referred to, are first, to provide a mixture of fuel and air ving the desired fuel and air ratio under all coQtions of opera- 45 tionand to deliver equal quan I ies of this mixtrim to each cylinder of the engine under various conditions of load and speed, without requiring the heating of the fuelor fuel mixture before it is delivered to the engine intake. Various devices are provided inthe carburetors dis- ?9 closed in the above applications for controlling the flow of fuel and air under various operating conditions so as to secure a mixture'having' the desired fuel and air ratio under every possible condition of engine operation.

The charge forming device forming the subject Fig. 12 is a fragmentary section on the line I "-42 of Fi 9.

I of the present invention is similar in general.

construction 'to' those disclosed in the aforementioned patents, and the principal object of this invention is to provide improved mechanismfor controlling the proportions of fuel andair in the 5 fuel mixture and to improve and simplify the construction of the device.

One feature of the invention consists in the provision of a fuel injecting pump, operative un der certain operating conditions for injecting fuel into the ingoing air at two points both posterior and anterior to the main air inlet valve, to pro-, vide ,the rich fuel mixture necessary for acceleration at higher speed.

Another feature of the invention lies in the pro- 16 vision of improved means forretarding the opening movement of the air valve to provide an enriched mixture for acceleration at speeds below that at which the fuel injection pump is effective. I j Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawingsfwherein a preferred form" of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is awplan view ,of the present invention shown in connection with an engine cylinder head block, portions of which are shown in horizontal section.

tion.

Fig. 5 is a sectional view" on the line 55 of h Fig. 4. 7

Fig. 6, is a sectional view, on theline 6-6 of Fig. 1. Fig. 7 is an end view looking in the direction of the'arrow 'I in Fig. 4.

Fig. 8 is an end view looking in the direction of the arrow 8 in Fig. 4. a v

Fig. 9 is a sectional view on the line 9-9 of Fig. 1. I

Fig. 10 is a sectional view on the line lit-I0 of Fig. 9. v

Fig. 11 is a horizontal section on the line I l-l l of Fig. 9.

Fig. 13 is an enlarged sectional view on the line lS-II of Fig; 12. Fig. 14 is afragmentarysectional view on the 55 line ll-ll of Fig. 9.

Fig: 15 is an enlarged vertical sectional view of 'the-dashpot piston and piston rod, blow-off valve and check valve.

Fig. 16 is a diagrammatic view illustrating all of the fuel passages supplying fuel to one of the primary carburetors.

Referring to the drawings, 2|! designates an air manifold'having an inlet at 2| (see Fig. 9)

and having three branch pipes 22 each cone nected with a cylinder head intake port 23. Each intake port 23 supplies fuel to a pair of engine cylinders through cylinder valve ports 23a and buretor unit which will now be described.

The main carburetor unit comprises a. housing 30, in the form of a single casting, which is attached to the flange 25 by screws 3|. The housing 30 provides an air chamber 32, the admission of air to which is controlled by an air valve 33 which is normally closed by a spring 34 against the valve seat 35 provided by an air born 36. The member 36 is attached to the member 30 by screws 31. For convenience in manufacture the member 30 is provided with an opening 38 which is closed by a plate 38. Thebottom wall 40 of the chamber 32 is provided with a large opening 4| to allow passage of air from the .chamber 32 to a chamber 42 from which air is supplied to the primary carburetors to be described. The air chamber 32 is connected with the air manifold inlet 2| by a passage 43' controlled by an air throttle valve 44 mounted on a shaft 45 which is supported as shown in Fig. 10 by the side walls of the chamber 30.

Referring-to Figs. 9 to 15 inclusive, there are as many primary carburetors as there are cylinder head ports, for example, three for a sixcylinder engine as disclosed. Each primary carburetor is provided by fuel-mixture passage or mixing chamber 50 into which there extends an upwardly projectjng fuel nozzle 5| provided with a metering orifice 52, open at its upper end and engine intake ports.

'to eliminate eddies in the primary carburetors.

The passages 56 are separated at their en trances. by. relatively thin partitions 58 which tend to prevent the interference of one carburetor with another. The connection of the air inletsof the primary carburetors with the air chamber 42 tends to "equalize the distribution of fuel to the This connection is believed The presence of eddies 'in'the primary carburetors would interfere with equal distribution since the eddiesare not constant in effect but are erratic. This-connecti n also tends to equalize the depression applied to all three carburetors, which might otherwise be unequal due to differences in the length ofthe primary tubes.

During the. choking of the carburetor when the air valve.33 is held closed, air is admitted to the air chamber 42 through small holes I in the bottom wall of .the chamber 42 in order to carry the liquid fuel .to' the engine for starting purposes. During the engine operation most of provided with small holes 53 adjacent the bottom of the passage 50. The fuel issues only from the holes 53 at idling and low speeds and light load; and abovelO to 15 miles per hour at light load for example, the fuel issues from the top of the nozzle 5|. At idling or low speed, light load, the depression at any nozzle 5| is insuflicient to lift the fuel through the outlet at the top of the nozzle, but does lift the fuel to a point intermediate the orifices 53 and top of the nozzle which establishes a gravity head at the said orifices 53, and causes the fuel to flow therefrom under the influence of such gravity head. The three primary carburetor passages 50 are arranged closely together in a horizontal'row as shown in Figs. 10, 11 and 12 so that they may be the air for the primary carburetors is admitted to the chamber 42 from the main air chamber 32; therefore it is apparent that the sub-atmospheric pressure at the fuel nozzles 5| will be substantially the same as in the main air chamber 32, up to a certain engine speed which in this carburetor is a speed corresponding to a vehicular speed of 20-25 miles per hour on a level. At higher speeds the velocity head becomes effective on the primary jets to form a super rich mixture, and is compensated for by opening the air valve to admit additional air as later described.

The bottom wall of the housing 30 supports a block 6 providing a distributing canal or manifold 62 having an entrance at 63 and a plurality of outlets 64, one for each fuel nozzle 5|. The block 6 in turnsupports a fuel metering block 65 which projects downwardly into the float bowl and provides a passage 66 into which fuel is normally metered through I an orifice 61 provided by a metering bushing 68. As fuel passes upwardly to the passage 66 it must normally all pass through a metering orifice 69 in a flow operated valve 10', and thence past a check valve disc 1| normally'resting upon a seat 12 and limited in its upward movement by stops 13. Above certain engine speeds, the velocity of theflow of liquid through the passage 66 is suflicient to raise thefiowcontrol valve 10 from its seat 1450 that fuel may fiow' also around the valve through passages l5, shown'more particularly in Fig. 13, as well as through the metering passage 69. Under certain vertically slidable' within a recess 84 provided by" the housing 36. A spring 85in this recess urges the valve 82 into closed position. The valve 82 is lifted by connections from the primary throttle .55 after a certain movement of the latter, such valve operating connections being more fully described hereinafter.

The liquid fuel which is supplied to all of the primary carburetors through the holes 61 and 8| is contained in a fuel bowl 98 suspended from" a frame FBI attached by screws 82 to a flange 33 provided by the member 30. Liquid fuel is admitted tothe bowl through a passage 94 provided in the frame 9| as shown in Fig. 6. This passage has an enlarged screen chamber 95 containing a fine mesh screen 96 supported by a fit- 'ting 91. having a tapped hole 98 for receiving a passage 04 extending brackets I06 integral with the frame "t eous SI-and an extension I 09 of the lever I limits counterclockwise movement of the lever and therefore retains the valve I03 within the valve seat member IOI when the float I06 falls.

The primary mixing chambers are formed in what may be termed a distributor block'A, which cast integrally as part of the housing 30, said block A projecting downwardly from the partition 60 as indicated in Fig. 9. Referring to Fig. 11, the center one of the primary nixing chambers 50 is in direct communication with a primary mixture tube IIO extending into the central branch 22 of the manifold 20; and each of the other carburetor passages 50 is. provided within the block A with. a right angle bend leading into a primary mixture pipe III having one end attached to the block A- and the other'end attached to a flange ,2 which is attached by screws II3 as shown in Figs. 1, 4 and,5

to the, air manifold 20 at a point in alignment with one of its end branches 22. This connection places the outlet end of each pipe III in direct communication with a primary mixture I pipe H0, extending through each of the end-branches '22fias shown in Fig. 5. Each engine intake port 21 provides a secondary carburetor in which the primary mixture issuing from the pipe) I I0, may

,be mixed with air issuing from each branch of the air manifold. It has been found advan- 1 to provide each engine intake port 23 with abushing Ill providing a Venturi passage .II 5 This passage has been found to increase the velocity of the primary mixture flowing through the tube H0 and oeleration of the engine.

therefore aids in ace The venturi also a sists in mixing the primary fuel mixture w'ith'the air inthe secondary carburetor. Other flow acceleratingmeans may be'substituted for the venturi if desired.

The. operating connections for the primary throttle valve 55 and the air throttle valve 44 opi ated. in

.will'now be described. It has been found desirable under part load conditions and for speed up to a'certain amount, for example, to an engine speed'co'rresponding to "a'vehicle speed of 20-25 miles per hour to supply all of the engine fuel mixtureby the primary carburetors only and above such certain speed to gradually open the air throttle 44 so that more air will be added to primary mixture in the secondary carburetors in-order that the fuel mixture will not become too rich during higher speeds. Accordingly, the throttlesv areso coordinated that the air throttle not be opened until the primary throttle "has been opened to a certain extent from its idling position shown in Fig. 9. As shown in Figs. Ilf'a'nd' 9, the primary throttle shaft 58 carries the main operating lever I20 having an aperture I2I for; receiving a control rod I20a which may be ing'eolumn of the vehicle propeliedby the en- 'gine. The lever I20 is pivotally'connected by screw I22 with a link I23 provided with a slot the usual-manner by an accelerator pejdal'or by a lever located at the top of the steer-,

I26 for receiving a stud screw I25 threaded in the free end of a lever 126 which is clamped in adjusted position around the air valve shaft 45 by a screw I21. A spring I28 connects the stud I25 with an ear I29 at the upper end of the link I23. Two ears I30 integral with the link I23 and formed by punching them from the main body of the link are provided with aligned tapped holes for receiving a screw I3I which may engage the stud I25. In Fig. 8, the levers I20 and I26 are in normal position corresponding respectively to the idle position of the throttle 55 and the closed position of the throttle 44 as shown in Fig. 9. The lever I20 is maintained in the desired position by its connection with the control rod I20a. The spring I26 tends to move the lever I26 clockwise and hence maintains the valve 44 in closed position. When the lever I20 is moved counterclockwise to open the primary throttle, the upper end of the slot I24 engages the stud I25, thereby causing the valve 44 to be opened after the valve 55 has been opened a certain amount. Further counterclockwise movement of the lever I20 as viewed in Fig. 8 will cause both .valves to move toward open position and their movement in this direction is limited by the engagement of the lever I26 with a stop l32. As

the lever I20 is moved clockwise to close the valve 55, the valve 44 will be moved into closed position through the connection including the link I23, the spring I28 and the lever I26. After the valve 64 has been closed the lever I20 may be moved in a clockwise direction until the screw I3I engages the stud I25. Since the valve 44 can not move any further in a clockwise direction from its closed position shown in Fig. 9, the valve 55 cannot be moved any further into closed position after the screw I3I engages the stud I25.

Therefore by turning the screw the idle position of the throttle 55 can be adjusted.

When the engine is running idle, the air throttle 44 will be closed, the primary valve 55 will be in idling position as shown in Fig. 9, and the automatic air valve 33 will be slightly open. As the throttle 55 is opened to increase the speed "of the engine, the depression in chamber 32 below the air valve will increase and the opening of the air valve 33 will increase automatically to admit air to the primary carburetor so that the required engine power will be obtained. Below a certain engine speed corresponding to a vehicle speed. of 20,-25 miles per hour, for example,

air valve 46 will remain closed so that all of the engine fuel mixture will be supplied through the primary mixture tubes I'l 0 by the primary carburetors. At aprimary throttle position of about 2025 miles per hour vehicle speed on a level road for example, the air throttle 44 will begin to open so that part of the air admitted by the valve 33 will be supplied by the air manifold to the secondary carburetor in order that the fuel' mixture will not be too rich for good performance and economy when on part load at intermediate speeds.

As has been stated previously, under engine operating conditions producing relatively high suction at the primary nozzles5l and consequent- 1y relatively high velocity of the flow of fuel through the passage 66, the metering valve I0 will be lifted to permit the passage of a greater amount of. fuel to the distributing canal 62. Normally this valve remains seated ,to keep the mixture lean below a certain medium speed, for example a vehicle speed of 30 miles per hour, when the vehicle isrunning on the level; or

under a certain lower speed under full load conditions.

The check valve 1I prevents the dropping of the column of liquid located above the level of the 5 -seat 12 in passage 66 down to the level of the fuel in bowl 90 when the engine speed-is suddenly reduced producing a consequent reduction in depression at the nozzles and velocity of fuel flow. Thus the valve 1| prevents starving the engine for a period, so that the engine will operate smoothly upon a sudden reduction in speed.

When only the primary throttle 55 is open all of the liquid fuel is metered through the orifice 61 in order to keep the mixture lean for rela- 15 tively low speed and light load operation or part throttle positions. For higher speed or greater load requiring the opening of the air throttle 44,

it is'desirable to meter more fuel into the passage 66. Therefore the valve 82 is caused to begin to lift as the valve 44 starts to open by means comprising a cam I40 attached to the shaft 56 and engageable with a lever I having a notched ear I42 for receiving a portion of the stem of valve 82 as shown in Figs. 7 and 12. The lever I4I is pivoted upon a screw I43 attached to a side wall of the housing 30. The frame 9| and the fuel bowl 90 project laterally beyond this housing so that the valve 82 may extend directly downwardly into the fuel bowl. It is apparent from Fig, 7"that after the cam I has been moved in a clockwise direction as viewed in Fig. '7 a certain amount. corresponding to an opening movement of the valve 55 as viewed in Fig. 9, the cam I40 will move the lever 85 MI in a clockwise direction as viewed in Fig. 7 in order to cause it to lift the valve 82. As the throttle 55 is moved toward closed position, the cam I40 will move away from the lever I to permit the spring 85to close the valve 82. The 40 opening of this valve begins at about 20 miles per hour, vehicle speed, for example, and continues during a considerable movement of the throttle. For example, the vehicle speed may be about 50 miles per hour when running on a level road before the valve 82 is entirely open.

The control of the air valve 33 for the purpose of choking the carburetor for priming the engine when starting will now be described. The air valve 33 is supported by a valve stem I which 50 is supported for vertical movement by a guide I5I screwed into the Wall of the housing 30 .,and extending at its lower end through a. hole in the bottom wall of the chamber 42. The guide I5I is provided with a shoulder I52 for limiting the downward movement of a sleeve I53 which is slidable upon the exterior of the guide I5I The spring 34 is located between the valve 33 ;and a grooved collar or spring seat I54 provided by the sleeve I53. Except when the carburetor is choked for starting the engine the sleeve remains in the position shown .in Fig. 9 against the shoulder I52. When it is desired to chokethe engine, the sleeve I53 is moved upwardly to increase the compression of the spring 34 so that 5 the valve 33 will be held closed and all the air for the/primary carburetors will be taken in through theopening 60 and a very rich mix-. ture will be produced due to the high depression at the fuel nozzles 5|. The sleeve I53 is m moved upwardly by a bifurcated lever I55 carrying studs I56 which are received by the grooved collar I54. The lever I55 is attached to a shaft I I51 provided upon the exterior of the housing 30 with the'lever arm I58 having a hole I56 for receiving a carburetor choke rod I58a. The spring 34 will return the lever I58 to the position shown in Fig. 4 against the end of an adjustable stop screw I60 after the choke rod I58a has been released. The stop screw I60 is-screwed into a clamp bracket I5I integral with the part 36 and is'clamped in any desired position ofadjustment by a clamp screw I62.

To prevent the fluttering of the air valve 33 and to retard itsmovement toward open position for purposes of acceleration, a dashpot is provided, including a. cylinder I10 located within 1 the fuel bowl 90 and cooperating with a piston I1I which is slidable upon a. piston rod I12 connected by a pin I13 with the lower end of the valve rod- I50. The piston rod I12 is provided withfa flange I14 having an annular bead I15 which functions as a valve'seat, the valve being provided by the bottom of the piston "I. A spring I16 confined betweenthe piston and a nut I11 screwed to the piston rod I12 tends to maintain the piston in contact with the valve v seat I15. The bottom of the piston is provided with ports I18 communicating with an annular space I18 between the bottom of the piston and the flange I14. The piston HI and the flange I14 provide a blow-oil valve, the operation of which will be described later. The flange I14 isprovided with ports I80 which m'ay b e closed m check valve disc I8I which is guided for vertical movement uponan extension I82 of the p ston rod I12. adjacent the flange I14 by a washer I83 attached to the lower end of the piston rod I12. Fuel is admitted to the cylinder I10 from the main fuel chamber 00 through a hole I in the, cylinder The .check valve disc I8I is held wall. The dashpot cylinder is provided with a by-pass pipe as shown in Fig. 12, for the purpose of producing a variable retarding eflect in accordance with the position of the piston I1I reintive to the cylinder I10. The by-pass pipe normally has its upper end closed by the dashpot piston when the air valve is closed. As the piston descendson opening movement of the air valve the said upper end of the by-pass is uncovered by thepiston, thus relieving the dashpot action and allowing the piston to, descend without material resistance after the by-pass is entirely uncovered.

While the engine is idling, the air valve 33 is opened but slightly because the depression in the chamber 32 is low. If the throttles are opened, as when accelerating the vehicle, thedepression increases, and the valve 33 tends to open quickly but its motion is retarded by the dashpot since the check valve I8I closes the holes I in the flange I14, requiring the liquid in the cylinder 0 all to leak around the piston "I. This damping effect persists relatively undimiuished until the by-pass I81 begins to be uncovered b the piston, during whichinterval, a richer mixture will be supplied to the engine for purpose of acceleration. Because of the greater inertia of the fuel, if the air valve were allowed to freely open on opening movements of the throttles, the increase in air "flow would take place much more rapidly than the increase in fuelv flow, which would result for a time in a weakening of the fuel m xture, until the effect of inertia was overcome. By retarding the opening of the air valve this increase in air flow can be prevented and by retarding the valve opening sufficiently this'weakening of the mixture can not only be prevented, but a mixture richer in the fuel content may be provided for purposes of acceleration.

The damping graduallydiminishes as the bypass I" is being uncovered to allow the valve 23 to open rapidly and supply air to the engine tolgive the required power as the fuel allow and engine-speed increase. The relation of the bymatically according to the position of the priless damping of the air valve would be-re-.

throttle 55. The greater the initial opening of the throttle 55 at the time it is suddenly opened further to accelerate, the less will be the, damping action. This variatiom is present bee quiredwhenmoving from a 20 to a 25 mile perhour'throttle position than from a 10 to a 25 mile per-hour position, assuming that the grade of the road is substantially the same under both fuel into the ingoing air stream. This tube is chiiditions.

Under certain operating conditions where the increase in depression below the air valve is very sudden, it is not advisable to retard the opening of. the air'valve. At such time the pressure upon the liquid in the dashpot may be great enough to overcome the spring I16, whereupon the piston will be lifted from the flange I14 of the pistop red to permit escape of liquid through the holes I10 in the bottom of the piston. As soon as the piston separates from the flange I14 it will remain separated until the pressureis reheved. -Thus it is seen in the present example,

the retarding of the air valve may be relieved entirelyv if-th'e throttles-bevery suddenly opened to a certain high speed position.-

Under part load conditions and up to certain throttle; openings, the dashpot constitutes means for enriching the fuel mixture for acceleration. 1

If 'it is desired ,to accelerate to higher speeds a substantial opening of the air throttween to prevent leakage. This assembly is secured by screws I84 to a boss I95 projecting up- 1 magnum the main housing. Means are provided to establish communication between the mainait passage 43 and the interior of the bellr ws'mi, such means comprising a passage I98 in tnewan of the housing 30 and a passage-I91 are. I98 screwed into arecess in-the of. bushing I98. ,The rod and guide sleeve boss kids, a check valve m is received in the above-mentioned recess between the end of the pagfiage I96 and the lower end of the bushing I90,-

val-ve having a small oriflce2li0 formed therein for a purpose hereinafter more fully set ceived'within a guide sleeve 203 having a flange at its lower end which fits tightly in a hole formed in the center of plate I92 and rests on he'ep the bellows vertical during its expanding [and collapsing movements. A spring 205 surrounding the rod and guide sleeve normally keeps theb llowsexpanded as shown inFig- 9.

1'.'uel is delivered to the space in housing ISI' outside the bellows through a pipe 200, the lower end of which extends below the fuel level in the fuel chamber 90. The upper end of this pipe is Two fuel delivery pipes 2I2 and 2I2a conduct fuel from the fuel spaceoutside the bellows I90 to deliver fuel to the main air intake passage at two different points. The pipe 2I2 is connected at its other end to a fitting 2 I3 secured by screws 2 to the air intake horn 36. This flttinghas va fuel passage- 2 I5 therein which forms a means of communication between thepipe 2 I2 and a short tube 2I6 extending into the air horn to deliver secured in the wall of the air horn in any desirable manner. A check valve 2I1 is received in a chamber 2I8 on the wall of the housing I9I, and controls flow through the pipe 2I2. The pipe 2I2a is connected at its outlet end in a hole in the housing 30 immediately anterior to the main air throttle 44, as shown in Fig. 9. This pipe is received at itsintake end in arecess formed in a 220 and a chamber 224 formed in the projecting portion of housing IQI and communicating with thedelivery pipe 2 I2a. A valve 225 is received in the chamber 224 and controls flow of fuel from passage 223 to the chamber. This valve projects through a plug -221 closing the chamber 224 and has a collar 228 secured by a set screw 229 to its upper end. An operating wire 230 is fixed to the collar and is bent horizontallyand downwardly in such a manner that its lower end engages the upper surface of the primary throttle operating lever to be operated thereby in a manner later 1 described.

' The above described pumping mechanism op 'erates in the following manner, reference being had-to the diagrammatic view in Fig. 16. At all times when the main air throttle 44 is closed or v nearly closed the high manifold vacuum main,- tained at points posterior to said throttle is communicated to the interior of the bellows I00 through the suction passage I96. This high vac-" uum collapsesthe bellows until" the depending rod 202 engages-bushing I98, creates a vacuum in the space around the bellows in housing Ni and such space. If the valve 44- is suddenly opened draws fuel through the supply pipe 208 to fill I the manifold vacuum'is reduced, the bellows ex- I pands and forces fuel out through the delivery pipe 2I2 and passage 22I. The fuel passing through pipe 2I2 is delivered directly and immediately to theingoing air stream through the tube 2I8. The valve 225, however, is closed on opening movements of; the-valve 44, since-the valve operatingstem 230 engages the upper side of throttle operating lever I20 and is permitted to drop to seat the valve as said lever moves coun terclockwise to open the throttles. Therefore on expanding of the bellows fuel is forced into the well and is retained there until the throttle lever I20'is raised to close the throttle'when said lever will lift the operating wire 230 unseating valve 225 and permitting fuel to flow from the well opened to increase the engine speed,when such fuel will be immediately drawn into the secondary mixing-chambers to enrich the fuel mixture,

for acceleration. This fuel travels a lesser distance than that injected into the air intake above the air valve, and passes immediately into an area of high vacuum where it is at least partially considerable number of moving parts, with con-.

sequent reduction in cost of. manufacture. Moreover, it is obvious that by providing two supplies of additional fuel for acceleration, which are successively drawn into the secondary mixing chambers, the pump disclosed herein is effective to enrich the mixture over a longer period of time than the pump employed in the earlier applications above referred to. In this device the dashpot is effective to take care of acceleration at all speeds'up to that speed at which the main air throttle starts to open, after which fuel is provided by the suction operated pump and by manual operation of the fuel valve 82 to enrich the mixture for acceleration at speeds above that at which throttle l4 begins to-open.

The check valve I89 with the small orifice 20!] therein is provided for the purpose of. preventing -.too sudden expansion of the bellows and consequently too rapid pumping of fuel to the mixture passage. On increase of pressure posterior to the valve 44 on opening movements thereof such pressure is communicated to the interior of the bellows rather slowly through the small hole 200 necessitating a rather gradual expansion of the bellows. v While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood. that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A charge forming device for internal com-' bustion engines having, in combination, a mixsupplying additional fuel to said air passage between the intake port and the throttle valve on closing movement of said throttle,

2. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, a main.

air intake port, an air passage receiving air from said main air intake port, a throttle valve therein, a fuel reservoir for supplying additional fuel to the 'air passage for acceleration, afuel pump operable on opening movement of fl cthrottle to directly inject fuel into the air intake port and fill the said fuel reservoir and a valve for controlling the flow of fuel from said reservoir.

3. A charge forming device for' internal comi 2,038,157 of the passage 43 until the valve (4 is again bustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, an air passage having a main air intake, a throttle valve therein, a fuel reservoir for supplying additional fuel for acceleration, a fuel pump operable on opening movement of the throttle to directly inject fuel into the air intake port and fill the said fuel reservoir, a valve for controlling the flow of fuel from said reservoir, and means for opening said valve as the throttle is closed.

4. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets thereforan air passage having a main air intake, a throttle valve therein, a fuel reservoir for supplying additional fuel for acceleration, a fuel pump operable on opening movement of the throttle to directly inject fuel into the air intake port and fill the said fuel reservoir, a fuel conduit extending from the said reservoir to the air intake passage at a point between the air intake port and the throttle valve, a valve for controlling said passa e and means for opening said valve as the throttle is closed.

5. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, an air pass sage having a main air intake, a throttle valve therein, means for injecting additional fuel for acceleration directly into the ingoing air on opening movement of the throttle and means for admitting other fuel for acceleration to the interior of the air passage adjacent and anterior to the throttle on closing movement thereof, whereby such fuel is available to enrich the mixture the instant said throttle valve starts to open.

6. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and airinlets therefor, a throttle valve,- an air passage having a main air intake port, a valve therein, a dash pot for retarding the opening movement of said valve to provide additional fuel for enriching the mixture on acceleration at low speeds, and a suction operated pump for supplying additional fuel to enrich the mixture on acceleration at high speeds, said pump comprising a chamber and two fuel delivery passages connecting said chamber and the main intake passage at two separated points ing chamber, fuel and airinlets therefor, a throttle valve, an air passage having a main air intake port, a valve therein, a dash pot for retarding the opening movement of said valve to provide additional fuel for enriching the mixture on acceleration at low speeds, and a suction operated pump for supplying additional fuel to enrich the mixture on acceleration at high speeds, said pump comprising a chamber and two fuel delivery passages connecting saidchamber and the main intake, one of said passages terminating adjacent the main air valve and the other of said passages terminating. between the main air valve and the throttle valve; 4

8. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, a throttle valve, an air passage having a main air intake port, a suction operated fuel pump for supplying additional fuelto enrich the mixture on acceleration, said pump' comprising a liquid chamber, a suction passage controlling the pump and connecting with the main air passage posterior to the throttle, a plurality of delivery passages comvidingfad'ditional' fu'el t'o delivery 'n ui s n or wmch1 e liv mews-v combustion enginehaving, in combination; a

' mixing chambeni uei' and air inlets therforya main; air intake passage, 9; throttle valve therein, a suction operated fuel pump for supplyin fuel to enrich the mixture, said pump comprising a, liquid chamber akflexibie bellows therein,' 'a'* supnleme'ntary fuei reservoir; e. plurality of fuel delivery passages connectin g the liquid ohambe'rf' with fthegeir jintake] passage anterior'i to the throttle and with the tn'elreservoir, a suction passage "conneeting the" 'interio jtwq; w eyais fi e ifei h. t valve therein adapted to. be opened on e iodyo l rc q nfi nea p a point ,adj acent the main air- J, valve and; the other I of 2 which idelivers fuel to, the secondary ai passage. a; y;

135A charge formingcdevio bustiona". engines; comprising; -aarmixture passage;

secondarykir v v *main air intake porqi'a. jvalvelin "said assage" 'means for opening said {valve only under cer-f he mixtgre vduring; he acceleration ans-; 9. Pr i M icon duitmcommunicat n -5w thuth i ar therein the admission 10f "to" the 1 mixture pas ag 2 a passage receiving: airfrom '---'said taiii operating conditions, and meansiorsupplying additional tuelduring the acceleration period onlyjsaid means 'c'ompris'ng a, plurality of fuel delivery conduits, one of 'whieh delivers fuel at a. point adjacent the mainintake va1ve,and'the other'oij which; delivers fuel to the secondary air passage.

15; A charge fforming device for internall' combastion engines' eomprising" aymixturefpalssage,

* means fofsuppiying fiiel' thereto, fa; mainiair valve for cbntroliingthe' 'admission of air to the t re Pa sa Sa main ai vaiv be f= nstrueted to openfiinder' all oonditionsfofpnem tion b h thlan lin 'as q d ryfl passage acceleration" per Qq' tl ur mygbr ru i;

'nlet iadjacentuthezvvalve ithereinmn ryair p'assag'ei respectivelyanterior t chakrgeiorming device or, inte1jna,1-eomustion-zenginesjIcomprisingwa -secon qysrmi in deliver a primary mixture of fuel and air to the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary mixture passage, an air valve in said inlet controlling the flowof air therethrough, a Secondary air passage for supplying air to the secondary mixing chamber, a valve in said passage for controlling the flow therethrough, means for enriching the mixture during the acceleration period, said means comprising aplurality of fuel delivery conduits communicating with the primary air inlet adjacent the valve therein and the secondary air passage respectively, and a valve in the last named conduit normally preventing a' flow of fuel therethrough.

19. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted .to deliver a primary mixture of fuel and air to the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary mixture passage, an air valve in said inlet controlling the flow of air therethrough, a secondary air passage for supplyingair to the secondary mixing chamber, a valve in said passage for controlling the flow therethrough, means for enriching the mixture during the acceleration period, said means comprising a plurality of fuel delivery conduits communicating with the primary air inlet adjacent the valve therein and the secondary air passage respectively, a valve in the last named conduit normally preventing a flow of fuel therethrough, and means for opening the valve in the fuel delivery conduit as the valve in the secondary air passage is closed.

20. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the sage, fuel and air inlets for supplying fuel and air to the primary mixture passage, an air valve in said inlet controlling the flow of air therethrough, a secondary air passage forsupplying valve in the fuel delivery conduit. I

21. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary mixture passage, a primary throttle controlling said primary mixture passage, an air valve in said ,inlet controlling the flow of air therethrough, a

secondary air passage for supplying air to the secondary mixing chamber, a valve in said passage for controlling the flow therethrough, means 7 for enriching the mixture during the acceleration period, said means comprising a pluralit qffuel delivery conduits communicating with mary air inlet adjacent the valve-th the secondary air passage respectivel in the'last named conduit normailyp 'h' aosanw' chamber, a primary mixture passage adapted to a flow of fuel therethrough, andmeans operated by the primary throttle on its closing movement for opening the valve in the fuel delivery conduit.

22. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adaptedto deliver a primary mixture of fuel and air to the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary mixture passage, a primary throttle controlling said primary mixture passage, an air valve in said inlet controlling the flow of air therethrough, a secondary air passage for supplying air to the secondary mixing chamber, a valve in said passage for controlling the flow therethrough, means for enriching the mixture comprising a plurality of fuel delivery conduits communicating with the air inlet adjacent the valve therein and the secondary air passage respectively, and means for forcing fuel through the first named conduiton' opening movement of the throttle and enabling a flow of fuel through the second named conduit on closing movements of the throttle. 23. A charge forming device for internal com- 4 ing the mixture comprising a plurality of, fuel delivery conduits communicating with the air in? let adjacent the valve therein and the secondary air passage respectively, a fuel reservoir communicating with the conduit connecting with the secondary air passage, and a pump operative to inject fuel into the air inlet and to simultaneously supply fuel to the reservoir. 24. A chargeforming device for internal conibustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary mixture passage, a primary throttle controlling said primary mixture passage, an air valve in said inlet controlling the flow of air therethrough, a secondary air passage for supplying air to thesecondary mixing chamber,.a valve in said passage for controlling the flow therethrough, means for enriching the mixture comprising a plurality of fuel delivery conduits communicating with the air inlet adjacent the valve therein and the secondary air passagerespectively, a fuel reservoir communicating with the conduit connecting with the secondary air passage, and a pump operative on opening movement of the throttle to inject fuel into the air inlet and to simultaneously supply fuel to the reservoir. 25. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and airto the secondary mixing chamber, fuel and air inlets for supplying fuel and air to the primary -mlxture passage, a primary throttle controlling said primary mixture'pas'sage, an air valve-in said inlet controlling the flow of air therethrough, a secondary air passage for supplying .air' tothe secondary mixing chamber, a valve in said passage for con-- bustion engines comprising a secondary mixing said secondary air passage, means operated by the ing movement of the throttle to inject fuel into the air inlet and to simultaneously supply fuel to the reservoir, and means operative on closing movement of the throttle to permit fuel to flow from the reservoir into the secondary air passage.

26. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the secondary mixing chamber, a primary throttle controlling the flow through said mixture passage, fueland air inlets for supplying fuel and air to the primary mixture passage, a valve in said air inlet adapted to open under all operating conditions except idling, a secondary air passage supplying air to the secondary mixing'chamber, a valve in said passage adapted to be opened only under certain operating conditions, and means for enriching the mixture during the acceleration period, said means comprising a plurality of fuel delivery conduits .communicating with the primary air .inlet adjacent the valve .therein and the secondary air passager'espectively. V

2'7. A charge forming device for internal comchamber, a primary mixture passage adapted to deliver a primary mixture. of fuel and air to the secondary mixing chamber a primary throttle controlling the flow through said mixture .passage, fuel and air inlets for supplying fuel and. air to the primary mixture passage, a valve in said air inlet adapted to open under all operating conditions except idling, a secondary air passage supplying air to the secondary mixing chamber, a valve in said secondary air passagejmeans for opening said valve only after a predetermined opening movement of the throttle, and means for enriching the mixture during the acceleration period, said means comprising a plurality of fuel delivery conduits communicating with the primary air inlet adjacent the valve therein and the secondary air passage respectively.

28. A charge forming device for internal com bustion engines comprising a. secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the secondary mixing-chamber, a primary throttle controlling the flow through said mixturepassage, fuel and air inlets for supplying fuel and air to the primary mixture passagea valve in said air inlet adapted to open under all operating conditions except idling, a secondary air passage supplying air to the secondary mixing chamber, a valve in primary throttle for opening; said valve after a predetermined opening movement of the throttle, and means for enriching the mixture during the acceleration period, said means comprising a plurality of fuel delivery conduits communicating with the primaryair inlet adjacent the valve therein and the secondary air passage respectively.

29. A charge forming device for internal combustion engines comprising a secondary mixing. chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to the secondarymixin'g chamber, a primary throttle controlling the flow through said'mixture passage, fuel and air inlets for supplying fueland air to the primary-mixture passage, a valve in said air inlet adapted to open under all operating condltions except idling, a secondary air passage supplying air to the secondary mixing chamber,

a valve in said secondary air passage, means op- 'erated by the primary throttle for opening said valve after a predetermined opening movement of the throttle, and means for enriching themixture during the acceleration period, said means comprising a plurality of. fuel delivery conduits communicating with the primary air inlet adjacent the valve therein and the secondary air pas-' sage respectively, means for eflecting the injection of fuel into the air inlet on opening movement of the throttle and the delivery of fuel to the secondary air passage on closing movement of said throttle. I

30. A charge forming device for internal com.- bustion engines, having, in combination a mixing chamber, fuel and air inlets therefor, a throttle, a main air intake port, anair passage receiving air from said main air intake port, a fuel reservoir adapted to supply additional fuel for acceleration, a fuel inlet receiving fuel from said reservoir and supplying fuel to said air passage, a fuel pump operable on opening movements of the throttle to directly inject fuel into the air intake port and fill said fuel reservoir, and a valve operable on closing movements of the throttle to permit a flow of fuel from the reservoir.

31. A charge forming device for internal combustion engines, having in combination a mixfor acceleration, a fuel inlet receiving fuel from said reservoir and supplying fuel to said air passage, a fuel pump operated by the throttle on opening movements thereof to directly, inject fuel into the air intake port and a valve operated by the throttle on closing movements thereof to permit a flow of fuel from the reservoir.

32. A charge forming device for internal combustion engines comprising 'a mixing chamber, fuel and airinlets therefor, a throttle, a main air intake port, an air passage receiving air from said main air intake port, a fuel reservoir adapted to V supply additional fuel to the air passage during the acceleration period, a fuel pump operable on opening movements of the throttle to directly inject into the ai'rxintake' port and to supply fuel to said fuel reservoir", and a valve operable on closing movements of the throttle to permit a flow of fuel from the reservoir to the secondary air passage.

33. A charge forming device for internal combustion engines comprising a mixing chamber,

fuel and air inlets therefor, a main air intake port, a secondary air passage for supplying secvondary air, a fuel inlet in said air passage, and a fuel pump comprising a chamber having a flexible bellows therein, and a plurality of fuel delivery conduits connecting said chamber with the air intake port and the fuel inlet in said air passage respectively. I I

34. A charge forming device for internal combustion engines comprising a mixing chamber,

flexible bellows therein, and a plurality of fueldelivery conduits connecting said chamber with the air intake port and the fuel reservoir respectively.

35. A charge forming device for internal combustion engines comprising a mixing chamber, fuel and air inlets therefor, a main air intake port, a secondary air passage for supplying secondary air, a fuel inlet in said air passage, a fuel pump comprising a chamber having a flexible bellows therein, and a plurality of fuel delivery conduits connecting said chamber with the air intake port and the fuel inlet in said air passage respectively, and means for communicating the manifoldvacuum to the bellows.

36. A charge forming device for internal combustion engines, having, in combination, a primary mixing chamber, a fuel inlet therefor, a throttle, a main air intake port, a secondary-mixing chamber to which the primary mixing chamber supplies a primary mixture of fuel and air, a secondary air passage receiving air from said main air intake port and supplying air to the secto supply additional fuel for acceleration, a delivery passage connecting the reservoir with the secondary air passage, and-a fuel pump operable on opening movements of the throttle to directly inject fuel into the air intake port and supply fuel to said fuel reservoir.

37 A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel-and air inlets therefor, a main valve and the other of said inlets delivering fuel betweenthe air valve and the throttle valve.

38. A charge forming device for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, a main air intake port, an air passage receiving air from the main air intake port, a throttle valve therein, a fuel pump for directly injecting fuel into the air intake for acceleration, a fuel reservoir for supplying additional fuel to the air passage to enrich the mixture during the acceleration period,

and a fuel passage connecting thepump with bustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, a main air intake port, an air passage receiving air from the main air intake port, a throttle valve therein, a fuel reservoir for supplying additional fuel to the air passage to enrich the mixture during the acceleration period, and a fuel pump operable on opening movement of the throttle to directly in ject fuel into the air intake port and fill the said fuel reservoir.

40. A charge formingdevice for internal combustion engines having, in combination, a mixing chamber, fuel and air inlets therefor, a main air intake port,'an air passage receiving air from said port, a throttle valve. in said air passage, means operative only temporarily for supplying additional fuel to enrich the mixture during the acceleration period, said means comprising two fuel inlets, one of said inlets delivering fuel adjacent the air intake port, and the other of said inlets delivering fuel between the air port and the throttle valve,

FRED E. ASEL'I'INE.

WILFORD H. 'I'EETER. CARL H. KINDL.

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