US1831376A - Carburetor - Google Patents

Description

Nov; 10,1931. 0. c. BERRY ET AL CARBURETOR 1 y a M d e 1..

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......1 Nov. 10, 1931 UNITED STATES PATENT OFFICE OTIO CARTER BERRY AIiID HOWARD W. .IJNKERT, 0]! INDIANAPOIJS, INDIANA, AS-

BIGHOBS TO THE WHEELEB-SCHEBLER CARBURETOB CO1, 01' INDIANAPOL'IS, INDIANA, A CORPORATION OF INDIANA CARBURE'IOE y time filed May 15,1923. semi im eaami.

This carburetor is an improvement'on'the carburetor invented b one of the present ap effective to damp out all fluttering, it tends to prevent a vigorous acceleration immediateafter coasting, for] the reason that it .1 fbrces the air-valve to openso slowly. It i go is therefore one of the objects of this invention to obviate-this difficulty.

(2) .As is also pointed out in the previous application, when the throttle of a carburetor is suddenly opened widen-at least a portion zs'of the gasoline will lag behindztheair in its passage through the intake .manifold of an engine, and this willresult in a temporarily impoverished mixture at the engine cylinder, often being'accompanied by 'atem- 30 porary lack of power or even by the stalling of the engine. This period of impoverish mentis very-short in its duration, however, and may be overcomebysupplying a temporarily enriched mixture at the carburetor. 35 It is also true that during periods of deceleration the liquid fuel flows to the cylinders in amounts in excess of the requirements, tending to cause the engine to load. Supplying extra fuel too rapidly during acceleration or supplying it for too long a time will produce inferior results during acceleration, but willbe especially bad in its effects when the ac-' coloration is inunediately followed by a deof this invention to'obvi-ate, these, difiiculties by accurately adjusting the amount of extra gasoline to the requirements of the engine,-

both as-to the rate of delivering it and the 60 length'of time during which it is delivered.v

When this dashlet 3 a passageway 4 .s r ted a'r-valve .mleration. It is therefore the second ob1ect p mg Sea 1 follows 1 Further objects of this invention are as (3) To furnisha well atomized mixture'of I I proper richness through a very wide rangeof rates of flow of the air through the carburetor.

(4) To furnish'the-engine with a leanand 5 part throttle.-

(5 To furnish the engine with such a mixture astoproduce maximum power when the I throttle is wide open.

(6)' To providea means that can be operated from-the drivers seat to enrich the mixture throughout the range for startin and for graduall reducing the amount 0 ing up. 5

such enrichment uring the period of warmeconomical mixture when it is runningat The accompanying drawings illustrate our" 1 invention, and show a preferred embodiment thereof. In such drawings: Fig. 1 is a plan view of a carburetor embodyin our inven-.

tion; Fig. 2 is a vertical,'long1tudinalsection thereof, taken on the line 2-2 of Fig.1; Fig. 3 is a transverse vertical section on the line 3-3 of Fi 1,; Fig. dis a partial eleva- 1 tion, showing t e control levers and adjustments; Fig. 5 shows the dash-pot piston in its normal position; Fig. 6 shows the action of this piston with a he'a ig. 8 is a planvi'ew Our carburetorhas a main bod 1 and-a the fixed-air passagewaiy,

1g. 3), an a venturi 5, plcking up and atomizmg the gasoline at the end of a gasoline jet'or nozzle 6 (Fig. 3) and, when this passageway is not large V suction suddenly apf fplied to the air-valve; i 7 is a plan view of the dash pot piston; and% of the dash-pot piston-washer.

enough, by a variable auxiliary-air passageway 8 (Fig.2) having at its entrances.-

pressed to allow'such' air to enter-through the auxiliary-air passageway 8- as is required.

which will be de-- In either case, the air passes through the body a v of the carburetor ast a throttle 9 and out through a mi'xture- 'scharge opening 10. The gasolineentersthefloat-bowl 2 through 11 and past a float-needle 12, and the gaso ne level is regulated by a float 13 0 eratin said float-needle. From the floatowl, t e gasoline is drawn'through the passageway 14 (Fig. 3) past a tapered needle or fuel-valve 15, and is controlled at the circular orifice formed between the top of the passageway 14 and the fuel-valve 15. It then passes through a cross-drilled hole 17 and the gasoline-nozzle 6 into the air stream in the throat of the venturi 5, and thence on through the carburetor with the air. The fuel-valve 15 has a short cylindrical section 18 by which it is guided into the orifice; and, as shown, has a considerable clearance in its guide above such cylindrical section, so that it is unnecessary that it be free from lateral swin ing.

As the rate of flow of air through t e carburetor is changed, the air and gasoline must be kept in the proper proportions. This is done by having an air-valve controlling the amount of air entering the carburetor, a fuelvalve controlling the fuel, and a proportioning-lever transmitting to the fuel-valve a definite portion of the motion of the airvalve, so that as the air-flow increases, the fuel also increases in the proper proportion. The details of this construction are as follows: To the auxiliary-air-valve 7 is fixed an arm 19 (Fig. 2) which is pivoted to one end of a proportioning-lever 20. This proportioning-lever passes through and has a close sliding fit in a supporting trunnion-block 321, which in turn is pivotally mounted on a fulcrum-pin 22 in the lower end of a pivotally adjustable fulcrum-arm 23. On the other end of the roportioning-lever is another trunnion-bloc 21, which is pivotally attached to the top of the fuel-valve 15 (Fig. 3), by a pin 24. Thus as the air-valve 7 moves, the proportioning-lever turns about the pin 22 and gives to the fuel-valve 15 a moa strainer cap 1 tion that is in proportion to that of the airvalve; and the proportioning-lever slides slightly in the trunnion-block 21 as required in this movement.

The suction causing the air to flow past the air-valve and the suction causing the fuel to flow past the fuel-valve bear substantially the same relation to each other at all rates of flow of the air through the carburetor.

6 to vary from a straight taper the shape of either the fuel-valve or the auxiliary-air passageway. We usually change the latter, as it is so much larger and there ore so much less sensitive to small changes; and use a straighttapered fuel-valve.

The method of, procedure in working out the proper shape for the inner surface of the auxiliary-air passageway is as follows: Tests are run at a large number of different rates of flow of air through the carburetor, and a record made of the weight of air and of fuel that passed during each test. From these figures the richness of the fuel to air mixture are computed for each rate of air flow. Suppose now that the mixture is found to be too rich at some particular position of the air-valve. The inner surface 25 of the auxiliary-air passageway is then hollowed out at this point until the mixture is brought to the required proportions. By this means the richness of mixture obtained at each and every flow-rate is brought to the desired point and the carburetor is made to follow the requirements of the engine with great accuracy.

The taper of the fuel-valve 15 is chosen to give the desired mixture when the fulcrumarm 23 is substantially at right angles with the proportioning-lever 20 when the auxiliary-air valve is closed, so that a small motion of the trunnion-block 21 in either direction will not materially change the position of the fuel-valve 15 and thus affect the idle adjustment. Shifting the trunnion-block 21 toward the air-valve will cause the fuel-valve to move farther for a given air-valve motion and result in an enriched mixture at all rates In order to provide a wide range of flowrate capacities, the fixed-air opening through the venturi 5 is made small, and the auxiliary air-valve 7 is made large.

The seating spring 26 of the air-valve 7 is made strong enough so that during operation the vacuum in the body of the carburetor will be sufiicient to atomize the fuel at the throat of the venturi 5, even at very low rates of air-flow. V

The low-speed adjustment is made as follows: The fuel-valve 15 (Fig. 3) has its seat in a sleeve 57,-which in turn is mounted in a threaded hole'58 in the body casting. This sleeve 57 has at its upper end a gear 59 (Fig. 2), which meshes with a worm 60 on the idle adjusting screw 61 (Fig. 3). Turning the screw 61 'will therefore screw the sleeve 57 3 up or down in the threads 58, thus raising or lowering the seat-for the fuel-valve 15, and making the idle mixture leaner or richer, respectively. 1

The enriched mixture for full power at open throttle is obtained as follows: The fulcrum-arm 23 which supports the fulcrumpin 22 is fastened to the fulcrum-arm-shaft 49. This shaft 49 passes through the body:

casting to the outside.

Arms 50 111 16 5 1 4) are fastened to this shaft 49 on'its outer end. The arm. 51- is'held'ag'ainst an" adjustrange of the carburetor throttle positions. The arm ing-screw 52 'in'a lu' 53 bya spring 54 (Fig. 3). ThQPOSltiOIl'O the screw '52 affects the position of the fulcrum-pin 22,and controls and fulcrum-pin 22 are moved toward-the air-valve, and in consequence .the fuel-valveis given a reater lift for a given air-valve motion, anfthe'mixture is made richer.

To obtain the rich mixture for starting a v coldengi'ne, a dash adjustment is provided which connects to the lever 50 through a wire 62 (Fig. 4).- Pulling down onthe wire 62 will turn the 'fulcru1n-arm23'to shift the trunnion-block 21 and fulcru1n-pin22 toward the airl-va lve'7 to increase the" lift of the fuel-valve to a given; opening of the air-valve, and even to cause a considerable lift ofsuch fuel-valve while the air-valve 7 is'on its seat, which results effectively in an enriched'starting mixture, asdesired.

A dash-pot 27 (Fig. '5) 'serves-to keep the air-valve from fluttering. The dash-,pot cylinder 27 lies below the fuel level of thefloat chamber 2 and is always filled with fueL- The dash-pot piston 28 is a good -fit in the cylinder 27,-an'd' is accordingly capable of ex erting a very strong damping effect on the fluctuations of the air-valve 7.

It is desirable to have the dash-potoffer less resistance to a closing thanv to an opening motion of theair-valve. This is-accomphshed by means of a disc-check-valve. The thin disc 29 lies on a shoulder on thenut- 30. Thisshoulder lies below the end-face of the nut 30, by a distance slightly. greater than.

the'thickness of the disc 29. The nut30 screws up firm ly against the drilled disc 31 shownalso in Fig. 8) Thedisc 29 is thereore free to drop below the lower face'ofthe disc-31 when the iston is rising, thus allowing fuel to flow through holes 32 in the disc 31, and-givin the'piston a comparatively fIGG'IIIOtIOII. 1 en the piston tends to 1 dc"- scend, however, disc 29 will rise and close holes 32, thus further retarding the motion 2 of the dash-pot piston.

It has already been pointed out that dashpots aspreviously constructed, wheneflt'ective 1n damping out all fluttering of the air-valve, will be too sluggish in their actionwhenr'a vigorous acceleration is desired immediately after coasting. This dash-pot obviates this difliculty. The dash-pot piston 28 is slidably mounted on the valve-stem 16,- but' is held against the disc 31'by a sp'ring 33. The fluctuations in the suction of the enginetending to cause the air-valve 7 to flutter when trunnion-block, 21

thethrottle valveil is wide open, are small i in :magnitude. The spring 33 is strong enough to resist; them completely the iston 28 to remain firmly 'in place and act like a solidly mounted piston, -'damping out all fluttering of theair-valve. J Whenthe and force car is coasting, however, the vacuum in'the intake manifold is very. high. When the throttle is kickedfopenunder thesef-condi- .tions, this high suction is transferred to the air-valve 7, causing a very strong pull inthe opening direction. Under .these conditions thespring 33 collapses as-shown in Fig. 6 a1? 5 I lowingthe' piston 28 and disc 31 to separate, and the air-valve 7 drops immediately, just as though thedash-pot were not there. v

Y The piston 28 is free to turnon the valve stem 16, while thedisc 31'is not. Itis neeessary that at least one of the. holes in the i 2 piston 28 register-withiahole in the disc 31. The disc 31 is therefore drilled with one. fewer holes than is thepiston 28, sov that: this resultis accomplished-no matterwhat-the position-of the piston.

Theimprovedacceleratingdevice is shown in Fig. 3. It is made as 'a'fuel-lifting mech anism-as distinguished froma pump. This distinction is an important point in the operation of the device, and willtherefore be broughtxout. clearly as the detailed description of the apparatus proceeds. *This fuel- 7 lift is preferably actuatedifrom the throttleshaft. In the f0Im Il1el8". shown, -the liftcylinder'34 is supported on'a lug 35 on'the carburetor body 1, by means of a threaded part 36. This lift-cylinder extends down into the, fuel-chamber 2. 'Thelift-piston 37 is fastened to the end of'a piston-rod 38. The piston:.is drilled toprovide holes 39. A thin check-disc 40 lies on to of the piston, and can move up to a shoulder 41 on the piston-rod- The fuel can therefore fill the lower end 3 of the lift-chamber, or lift-chamber proper, through the holes-39. A "reduced section of the lift-chamber, the part or passageway43, extends from just below the fuel level in the ,float-chamber 2, to some '.point sufficiently above suchfuel level so'that tipping the carburetor will never submerge its; upper end in practice. This 'sect-1on :1s reduce reducing the amount the piston 37 will have to .move before beginning: to deliverfuel through sufficiently restricted to interfere 1 with the the part 42 free deliver of fuel through itgin-either di rection. en the lift-piston is raised,the fuel can therefore -fiow'freely through the section 44 or measuring chamber of the liftchamber: From here it can flow throughthe cross-passage 45 into the venturi 5. The

rate at which theextra fuel is delivered. to the- 12o said cross-passage 45; but it is not 126 reduced section 43 "into'an .upperenlarged V This ring 47 is in no wise, a check-valve.

' line necessary.

I smaller, and

venturi will be determined by the size of a hole 46 .in such cross-passa e. A ring 47 has a. loose fit on the piston-r0 in the upper section 44 of the lift-chamber, and serves to keep the fuel from being ejected througha cap 36 when the lift is being used vigorously.

passageway 48; -It is therefore'possible to fill theupper section 44 witha small movement of .the throttle, and an a fuel pumped into such upper section 44v yond the required amount will pass through the overflow passageway 48 bac into the fuel ch'amber again. The total quantity, of extra fuel supplied is therefore measured in this small elevated chamber-section 44, and this quantity be determinedby the height the over- 48 is given when the carburetor is built;

. By this means it is possible to supply the full I lowing char of fuel and load of extra fuel for acceleration with a sma opening movement of the throttle without wasting fuel or causin the engine to load when thethrottle is kicked wide open.

' Thediiference' between our lift apparatus and a pump lies inthe fact that we have only a single check-valve and have a fuel liftchamber that is in continuous 'free communication fromthelift-piston to the overflow passageway 48, while a pump has two valves and twofuel chambers. In our apparatus a rapid raisingand lowering of the lift-piston will merely raise and lower the same fuel in the lift-chamber, resulting in a very small delivery of fuel from the top. In a pump, however, each stroke of the piston will deliver a definite volume of fuel. In an accelerating device this will result in the foldiiference in performance: When the throttle is openedwide and'then quickly closed with a -pump'accelerating device attached, the full charge of extra fuel for acceleration will nevertheless be added, and

a full charge of extra gasorying out of the essential idea of our inven-' tion.- It is furthermore not essential that the accelerating device be an integral vpart livered on the up-strokeof the lift-piston, and these features are shown as illustrative; I \Ve claim as our invention: r 1. In a carburetor, the combination with .a suction-actuated air-valve, of a dashdamping the motion of said air-va Va and made up of-a-dash-pot chamber, a piston-rod, a piston slidably mounted on-said piston rod, 9, stop at the end of said piston-rod, and a spring pressing said piston against said stop, 2. In a carburetor, the combination, with a suction-actuated air-valve, and an air-valve V stem; of a dash-pot for damping the motion ofsaid air-valve and made up of a dash-pot 1 chamber, a dash-pot piston having a sliding fit in said dash-pot" chamber and slidably mounted on said air-valve stem, a stop at the piston end of-said air-valve, stem,-and at spring pressing said piston against said sop.

. 3. In a carburetor, thecombination' with an air-valve, a fuel dash-pot for damping the motion of said air-valve and consisting i of the carburetor, nor that thefuelbe detfor foo

05 in adashot chamber so located as tobe filled with uel, a dash-pot piston-rod,.a dashpotpiston havin a'sliding fit in said dashpot'chamber an slidably mounted onjsaid piston-rod, a stop at the end'of said pistonrod and a spring pressing said piston against I said stop. V

4. In a carburetor, the combinationlof a suction-actuated air-valve; and a dash-pot for damping the motion of said air-valve and,

consisting in a dash-pot chamber, a piston yieldingly connected to said air-valve, and I means enabling said piston to act 'as'a solidly'mounted piston under slight impulses but to givelway readily under a heavy impulse. '5; In a carburetor, the combination of" a suction-actuated air-valve; and a dash-pot consisting in a dash-pot chamber, a 'piston yieldingly connected to said air-valve, means enabling said a piston to act as a solidly" 'mounted piston under slight'impulses but will be added-at a timewhen it is not only to give way readily under a heavy impulse, not needed, but when the engine is already predisposed to loaddue to the fact that it is decelerating. In our lift device this is not the-case, as the extra fuel raised on opening the throttleis immediately withdrawn when the throttle is closed. Furthermore, repeated 'openingand c losing of the throttle attached to a fpump will deliver an excessive amount I the eng ne while such a result willnever occur with our'apparatus.

()ur acceleratingdevice is capable ofwide variation from the-preferred for ngshown.

and meansfor allowing said piston tomo'vq for damping-themotion of said air-valve and more freely in one direction than in the other, said last named means being a checkvalve arranged to open as said air-valve closes but to close automatically as said airvalve is opening. 1

7. In a carburetor, the combination with a mixing-chamber having an air-inlet opening, a throttle, a fuel-supply chamber, an air-valve tending to close said opening, and a fuel-valve; of means for damping the motion of said air-valve consisting in a dashpot mechanism yieldingly connected to the air valve and capable of resisting small impulses but giving way disproportionately quickly under strong impulses.

8. In a carburetor, the combination of an air valve subjected to a variable tendency to be moved, and a dash pot connected to said air valve for normally damping the movement thereof. said connection including means normally maintaining a fixed relationship between the air valve and dash pot. but being yieldable to permit the air valve to move with relatively decreased dash pot retardation upon the occurence of a predetermined tendency to move the air valve.

9. In a carburetor. the combination of a suction actuated air valve and a dash pot connected to said air valve for normally damping the movements thereof. the connection between said air valve and said dash pot being normallv rigid but including means yielding at a predetermined pressure to permit the air valve to move with relatively decreased dash pot retardation upon the occurrence of a predetermined pressure acting to move the air valve.

10. In a carburetor. the combination with a mixing chamber having an air-inlet opening. a throttle. a fuel-supply chamber. an airvalve tending to close said opening. and a fuel-valve: of means for transmitting a portion of the motionv of said air-valve to said fuel-valve. and means for damping the motion of said air valve and the resultant motion of the fuel-valve consisting in a dash-pot mechanism yieldingly connected to the air valve and capable of resisting small impulses but giving way disproportionately quickly under strong impulses.

11. In a carburetor. the combination of a fuel-valve. and a dash-pot for damping the motion of said fuel-valve. said dash-pot including a piston yieldingly mounted relative to the fuel valve and arranged to act as a solidly mounted piston upon slight impulses but to give Way readily under heavy impulses.

In witness whereof, we have hereunto set our hands at Indianapolis. Indiana, this 12th day of May, A. D. one thousand nine hundred and twenty three.

OTTO CARTER BERRY. HOWARD W. LINKER-T.

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