US2868522A

US2868522A - Carburetor

Info

Publication number: US2868522A
Application number: US678929A
Authority: US
Inventors: William E O'neil
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-08-19
Filing date: 1957-08-19
Publication date: 1959-01-13
Anticipated expiration: 1976-01-13

Description

Jan. 13,r 1959 `w. E. o'NEl'L CARBURETOR Filed Aug. 19, 1957 I?? vente?" Milka/M ez'Z lll/1711111111 `auxiliary chamber or casing.

United States Patent O My `invention is` concerned with carburetors and is a new and improved carburetor `constructed and arranged to `operate more eciently `and is specifically aimed at eliminating or reducing llattspots during acceleration Aandvarious other features.

A` primary object of my invention is a new and improved carburetor which will momentarily supply a rich "mixture during acceleration.

Another objectsis a carburetor that does away with an accelerating pump.

Another.. object is a carburetor which automatically provides a` momentary rich or chemically correct mixture duringl acceleration to eliminate flat spots and slow acceleration. v

Another object is a carburetor with a controllable venturr arranged automatically to eliminate ilat` spots by supplying a richer chemically correct mixture. l

Another object is a carburetor of the above type constructed for proper idling;`

Another object is a carburetor of an auxiliary choke.

Other objects will appear from time to time in the ensuingspecication and drawings in which:

Figure Il is a vertical section of my carburetor with all ofthe parts in their lowerrnost orinoperative positions;

Figure`2 is` atsection along line 2 2 of Figure` l; gigure 3 is atsection` taken along line 3 3 of Figure 1; .an

t Figure 4 is an enlarged longitudinal section of the metering pin.

A generally cylindrical casing, as indicated generally at 10, at its lowerV end has an auxiliary'or inlet casing 12 the above type with `andoat'vits upper end a top'1cap or the like 14. t The `auxiliary chamber or casing 12 has a suitable inlet 16 and the main casing or housing is provided with a suitable outlet` 1S which` may be connected' to an internal combustion engine of any suitable type. For example, itimight be connected through a suitably heated gooseneck or the like. Theoutlet may be provided with` the usual throttle valve; indicated generally at 26.

A lloatchamber, indicated generally at 22, to` one side of thermain" upright casingL or housing, is provided with auf extension or projection 24" which, on its upper surface, properly seats and engages the maincasing, as at 26, and onuits lower surface is properly fitted into or otherwise connected to theauxiliary casing, as at 28. The details of these connections are unimportant. For example, in Figure l, themain casing 10 is provided with an outstanding flange which mates' with .a corresponding flange on the float chamber projection. The lower portion of the float chamber projection extends into and seals the These parts are conventional and' in themselves Vare not important `to this invention.. t

A fuel supply communicates with the float chamber through a suitable connection or pipe 30, the joint being providedwith a-suitable strainer or the like 32, if desired.

" Felrises through aV suitable passage 34 in a conventional 2,868,522 Patented Jan. 1s, 1959 ICC `fitting 36 which" threads' or otherwise connects with' the bottom" of the lloat'll chamber. A suitable oat 38"co`n trolling a valve element 40 is provided to` open and close the passage 34` leading into ,the float chamber in accordance' with the height of the ,fuel in the lloat chamber. A Asuitable passage"42 with a lateral extension orbranch 44 may be provided.l in the tloatjchamber projection to supply fuel from `the `o`at chamber to the carburetor casing proper. j

The outer end ofthe float chamber extension or projection is provided with a threaded bore as .at 46. Screwed into the `bore `and rising upwardly into the casing is a stationary fuel nozzle 48. Around and slidably mounted on the fuel nozzle isi a cone-shaped element or cone 50 which,` in its `lowermost position,.engages` a` suitable seat 52 on the float chamber extension or base. j An air valve `5.4 is slidably disposed"in` the bore or passage` through the casing" and includes alower ring 56 or the like antifa' plurality of arms or struts-58 rising up-` wardly to an upperpiston4 `6l). The upper piston is disposed j generally in thelupper part ofthe casing, as shown in `Figure l, generally above the outlet 18. The lower ring` 56, struts 53, and upper piston 60 may be integral and move as a unit.` The air valve may be prevented from. rotating inthe casing by a suitable key 62.

A metering pin 64A is` carried by the upper piston 69, as `bya\pin.66,` and projects down into a bore 68. in the fuel nozzle 48. It. will be observed that the bore 68 of the fuel nozzle communicates with the passage 44 in the float chamber extension so that fuel will rise to a certain predetermined level in the bore 68 in accordance with the level maintained `in the` oat chamber by 'the oat. 'Ifhe metering pin is provided with a plurality of longitudinal grooves or` channels 70,which are preferably tapered, so that` in accordance` with` the suction or vacuum communicated to ther casing `or housing by the engine, more orless fuel may be drawn through these grooves into the moving air stream.

In the lower chamben12 I `provide atthermostat, indicated generally at 72, which may include a bellows or Sylphon-tubet74having aniupper portion "lrscrewed into the bore 46` or otherwise suitably connected to the iloat chamber extension so that the top of the bello-ws Willtbe fixed. The bottom of the bellows issuitably connected by a cross piece 77, as shown iii-Figure 2, to two or more tie rods 7S which transmit the expansions and contractions of` the bellows, `responsive to changes in` ambient temperature and pressure, tothe cone. The upper ends of the tie rods are threaded into or otherwise connected .to the cone, as shown in Figure 2, and held by suitable lock nuts Sil or the like. s A metered opening 82 may be `provided in the upper piston dito vary the responsiveness `PatentsNo. 1,586,601 andt2,203,858. The general operation of a` carburetor of this nature is that vacuum is `communicated-tothe maint casin-g orhousing through the outlet 18. In response tothat vacuum the air `valve 54 tends to rise, thereby s eparatingthe lower ring or `valve, `56 from the cone 50. The upper piston 60 also rises with the air valve and carries the metering pin 64 with it. Air flows through the inlet 16, through the lower housing 12,15- tween the cone 50and ring 56, and through the main casing past the now exposed fuel groove or grooves 70 in the metering pin drawing fuel from the bore 68 of the fuel valve into the casing causing a fuel-air mixture of proper proportions which is carried throughthe outlet 18 to the engine. The degree of vacuum will varywith the load and speed of the engine. The air valve will be raised v gine.

`56 on the air valve.

lack of fuel. In other Words, they starve.

assume that an engine is idling and the throttle is thrown K 'flange and the inside o f the casing.

Y'distance of the ring 56, but it might be otherwise.

loadsor high speed, the -air valve will rise a substantial amount exposing wider portions of the grooves 70 in the metering pin thereby admitting more fuel for the en- In cold weather, the bellowsf74, which may be 4filled with a suitable temperature responsive substance, such as ether or a mixture of ether and other alcohols, contracts raising its lower portion and :also tie rods 7-8, resulting in the cone 50 rising on the fuel nozzle 48. The air valve is raised with the cone, ina manner to be set ,forth hereinbelow, so that the metering pin is also raised exposing the grooves so that more fuel is supplied than in normal operation. Therefore, in cold weather a rich mixture will be provided to the engine. As the temperature of the ambient air increases the bellows 74 will vexpand, vlowering the cone and bringing the metering pin 1back to normal.'

In cold weather, the bellows 74 intresponse to lower ambient temperatures will contract, thereby raising the cone 50 and the flange 84 relative to the housing and the ring The flange will effectively prevent the passage of air between the inner circumference of `the air valve at its lower end at the ring 56 and the periph- `ery of the base of the cone 50. This, in eiect, functions as anvauxiliary choke excluding air and increasing the amount and flow of gas into the housing so that the engine will start more readily in cold weather.

During rapid acceleration engines normally suier from For example,

immediately to three-quarter load. ,This opens the valve 20and full suction from the engine is communicated to -the inside of the casing. The air valve will quickly rise,

supplyingthe full quantity of air for that loadand speed, but the viscosity and inertia of the fuel causes a momentary lag in the fuel supply which results in a momentary lean mixture for the engine. This condition or hesitation has been conventionally referred to as a flat spot in they carburetor and is conventionally taken care of by an 'accelerating pump, which is nothing more or less than a pump to supply an additional shot of fuel to raise the lean mixture to the proper air-fuel ratio only momentarily during acceleration. After the viscosity and inertia vofthe fuel in the carburetor has been overcome and the proper air-fuel ratio mixture is being supplied by the carburetor itself, the accelerating pump is no longer necessary and does not operate.

An accelerating pump is an extra piece of equipment which involves complications and expense. It has long been the desire of manufacturers to do away with it where possible, and in carburetors of the above type, it has never successfully been mastered prior to my invention.

To accomplish this end, I provide a small flange 84 outstanding from the bottom of the cone and underlying the ring 56 on the air valve. This ange provides, in effect, a right angled shoulder or seat 86 at the bottom of the cone onto which the lower inner edge of the ring 56 rests or seats. It should be noted that an annular gap or passage 88 is provided between the outer edge of this I prefer that the ange extend out approximately one-fourth of the radial The flange is preferably integral with the cone and may be easily formed in the same machining operation as the cone,'but it might be otherwise.

The function of the flange is three-fold. First, it serves to raise the air valve with the cone when the bellows 74 ,contracts in response to relatively low ambient temperatures. ,When the cone israised by thebellows, the flange 4will also pick up the ring 56 which raises the air valve and metering pin functioning to supply a rich mixture for the engine in a manner iset forth hereinabove. Second, during rapid acceleration the ange prevents thel formation of a flat spot in the carburetor. It functions in the following manner:

Assume, for the moment, that the engine is idling and is brought quickly to three-quarter load or full load. The valve 20 is thrown open and a substantially increased or possibly full vacuum is communicated to the carburetor. The air valve starts to rise quickly, which would normally create a quite wide gap or venturi between the ring 56 and the cone 50. But the outstanding flange 84 at the bottom of the cone provides a mild but effective momentary seal or restriction between the lower edge of the ring 56 and the cone. The increased Vacuum; during acceleration causes the bellows in the air stream to contract, in response to atmospheric pressure, causing the ange 84 to momentarily rise and approach or possibly go in contact with the lower edge of the ring 56, temporarily restricting the throat of the venturi. This brings about a higher velocity of the air and a lower pressure through the venturi and, therefore, freer flow of the gas. As the ring starts to rise with the air valve, the cone is drawn up with it by this seal. The vacuum, in eiect, draws up the cone through the medium of the bellows. In effect, the vacuum or pressure differential causes the cone to rise due to the seal provided by the flange 84 with the bottom of the ring 56. The vacuum will compress the bellows 74 slightly. During this short period, the metering pin will rise and the grooves 70 in the metering pin will be exposed above the upper end of the fuel valve 48 and additional fuel will yilow into the casing. In other words, the vacuumabove 'the cone 50 and ring 56 and flange 84 will not be immediately relieved because the cone tends to followfthe `ring up. This increased vacuum is communicated to the choke.

At the same time, the air ow through the housingis restricted momentarily because thefflange of the cone 50 remains in contact with the ring S6. Therefore, two factors are working against the creation of a lean mixture. First, the inertia of the fuel is partially overcome because a larger vacuum than normal is pulling it into the casing. Second, the amount of air that passes through the casing to mix with the fuel is less than normal. Thus, I provide not only avariable venturi but a controllable venturi since the momentary seal will provide momentary and instantaneous control over the air-fuel ratio during rapid acceleration to eliminate a at spot. Therefore, instead of having a momentary lean mixture, a substantially chemically correct or richer mixture will be supplied and no flat spots Will result.

The contact between the lower edge 86 of the ring and the ange at 84 is by no means an absolute seal and the sealing effect during rapid acceleration is only momentary. Nevertheless, it is during the initial part of a rapid acceleration that at spots occur, which in the past have resulted in slow acceleration, insucient power and, on occasion, misring because the mixture is too lean for ignition. But with this invention, the flat spot is overcome, the mixture resulting in the casing is more chemically correct, and under certain circumstances may be on the rich side, if desired, and an accelerating pump is no longer necessary.

A carburetor of the above type must idle properly, but priorto my invention it has proved very difficult. I solved this otherwise seemingly ditlicult problem by extending one of the channels :or grooves 70 on the metering pin, as at 90 in Figure 4. The upper end of the fuel valve 48 and the metering pin 64 are shown in their lowermost or idling positions in Figure 4. One or possibly two chan- ,nels are extended a predetermined distance X above the drawn into the casing during idling. This in combination with the mildly effective seal caused by the flange 84 on the bottom of the cone in engagement with the ring 56` the bottom of the bellows 74.` The screw may be manually adjusted so as to raise and lower the rods 78, compressing the bellows, and raising and lowering the cone. Thus, for any particular engine, the carburetor can be set for maximum eiciency'with one simple adjustment.

It should additionally be noted that `the `bellows and tlange 84, in combination, have a pump effect in that they take the place of the accelerating pump. This is to say that they function as an accelerating pump in that they restrict the air flow and increase the fuel flow.

While I have shown and described a preferred form of my invention, it should be understood that numerous additional modications, substitutions, alterations and changes may be made Without departing from the inventions fundamental theme. For example, the details of the bellows 74 are totally unimportant. The `connection between the fuel line 30 and the oat chamber 22 is also unimportant to this invention. The iioat mechanism 38 in the tloat chamber may be of `anysuitable type.` With these and other modifications and changes in mind, I wish that the invention be unrestricted, except as by the appended claims.

I claim: i

1. In a carburetor for an internal combustion engine or the like, a generally open casing having an air passage, an air intake `communicating with the casing, a Vcone element constructed to partially close the passage through thecasing, a fuel nozzle element extending through the cone, the cone and fuel nozzle being mounted for relative movement, one being iixed relative to thecasing, the

other beingrmovable, a seat in the passage xed to theV casing and constructed to accept and seat the movable element,lan air valve constructed with the cone element to substantially close the passage when the engine is `not operating and movable away from the cone element to provide a variable area orice with the cone element in response to the vacuum created when the engine is operating, a metering pin having grooves therein extending into the nozzle element and movable with the air valve to open the grooves for admitting variable quantities of j fuel, and a peripheral ange betweenithe air valve and cone elementwhich functions as a seal for momentarily preventing the admission of air between the cone element and` air valve, during rapid acceleration, so that with a given amount of fuel drawn through the grooves in the metering pin, the air supply will be momentarily reduced to provide a relatively rich mixture for the engine.

2. The structure of claim 1 in which the ange is continuous.

References Cited in the tile of this patent 2,203,858 Booty June 11, `194() Booty June 1, 192s` v