US1325688A - Thomas w - Google Patents

Description

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CARBURETER.

APPLICATION FILED D CT. i6 191?.

1,3,fi v Patented Dec. 28, 1919.

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Specification t Letters Patent.

Patented nee. 2s, iota.

Application filed October 1.6, 1917. Serial no. 196,943.

To all whom it may concern:

Be it known that I, THOMAS W. Born, a a citizen of the United States, anda resident of Stoneham, county of Middlesex, and State of Massachusetts, have invented an Improvement in Carbureters, of which the following is a specification.

This invention relates to that class of carbureters known as suction teed carburetors, or. those in which the liquid ruel is lifted from a low level tank to the oarbureter by the suction action of the engine, or motor.

While various types of carburetors of this class have been produced, they are, so far as I am aware, objectionable in that they involve the use of automatic valves, such "as float and check valves, auxiliary tanks and other devices, all of which add materially to the cost of manufacture, and some of which require careful adjustment, and are liable to get out oi. order or require frequent readjustment. Moreover, these devices are, so far as I am aware, adapted to position only, i. a, the upright position, and are practically inoperative in any' other position.

The object of my invention is to produce a suction feed carbureter which is adapted for practically all conditions of use which may he demanded, which will effectively mix the liquid'fuel with the air, and apdesired relative proportion of air and vaporized iuel under all variations in thethrottle opening, so that high efiiciency may be secured, and, further, to produce a carbureter which is oi. such simple construction that it may be made at a relatively small expense and which makes unnecessary the employment of automatic valves, such as float valves and check valves.

1 accomplish these objects by the means shown in the accompanying drawing in which 7 'Figure l is a plan view of a carbureter" embodying my lnvention.

Fig. 2 1s a sectional view, at line 22 of Fig. 1.

Fig. 3 is a device.

Fig. i is a sectional view at line 4-4: of Fig. 2. v

i Fig; 5 is'a side view, and

Fig. ncctions.

.ment being preferable, count oi convenience in I versely, in such aposition p 11 and is provided view of the suction end of the extends through 6 is a view showingthe tank con As shown in the drawing, the carburetor casing is composed of two tubular SGCtlOHf-l 8 and, 10 which are provided with abutting flanges connectedby screws 9,'this arrangeprincipally, on acassemblin the purposes of the invention, t e casing members 8 and 10 will be considered as a single casing, one end of which, (the outer end of member 10) is designed to be connected to the engine or motor, end of which is open to the atmosphere.

and the other i but, tor

According to my invention an aperture 11 is bored entirely through the casing, transthat the center passage throughthe casing at right angles, and also lies in the plane of contact of the casing members 8 and 10.

A plug 12 is threaded into said aperture tral passage 14, the outer end of which is chambered and threaded to receive the end of the supply pipe 16, which is connected thereto, and is extended downward to the bottom portion ofa vented low level supply tank 'l8,to which it is also connected, as indicated in Fig. 6. The inner end of said plug is tapered or flared to provide a seat for a needle valve 20, as hereinafter described.

A tube 22 is closely fitted and rotatably and slidably mounted in the aperture 11, said tube being arranged to extend across the passageway through the casing,,so that its ends bear at opposite sides of said passageway. The opposite end from the plug 12 is rigidly connected to a tube 24, the latter being inserted therein so that the end oi the tube 22 may act as a shoulder. The tube 24 is slidably and rotaof said tube 22,

with a longitudinal cen-p tably'movable in the bore of a plug 26,

formed by the adjacent endof tube 22. A

cap nut 30 is threaded on the outer end of the tube 24 and the stem of the needle valve and is threaded in said nut and in the outer end of the tube 24',

' so that, by rotating the necdleyalveby its handle 21, its position with relatiomtoits seat in the end of the plug l21nay1bo varied. The screw threads between the nut SO adjusted.

and the exterior of the. tube 2& have a different pitch than those between'the shank of the needle valve and .the nut and the iiiterior of said tube, so' that, to adjust the needle valve, it is necessary to hold the nut from turning in a position in which the needle valve may be turned freely to the desired point. When this has been done the nut is released, and the needle valve is turned in slightly, immediately causing the threads to j am, so that the needle valve will be securely locked against becominig unscrewed or moved out of the position to which it was I A cam 32 is rigidly secured on the tube 24:, between the nut and the outer end of plug 26, and correspondingly inclined faces [are formed on the adjacent sides of said cam and plug, so that, whenthe cam is r0- tated from its initial position, shown in Fig. 4, the needle valve will be drawn away from its seat. An arm 34 is formed integral with.

the cam 32, to which the throttle operating means isconnect'ed.

A throttle valve 36, of the butterfly type,

is rigidly mounted on the tube 22, within the casing passage, and an annular, internalrib 38 is formed within said passage, which substantially reducesorconstricts the area thereof at this point and the opposite sides of which provide seats for the opposite portions of the throttle valve. It will be ap parent'that, when the tubes 22 and 24 are rotated by arm 34-, the valve 36 will be opened orclosed.

An opening 22 is formed in the side of the tube 22, at the side of the throttle valve which, when closed, faces the suction side 10 of the carbureter casing, or portion of the casing which is connected to the engine,

' said opening beingnearly as large asit is practicable to make it, extended nearly half way about the tube and lengthwise thereof,

.- throughout nearly the entire diameter of the .screen 4.0 the meshes passage portion inclosed by the inner edge of the rib 38. Said opening is covered by a of which are preferably very fine.

v The air intake end of the casing may be justed so that, when the throttle valve is closed, the needle valve will'be held in con tac't with its seat on the end of plug 12, or it is adjusted to permit a slight leakage,

sufficient to run the engine without any load,

the latter adjustment being preferable under most conditions. I As the throttle valve 36 is swung from closed position by the arm 34, the cam 32 will ride on the cam face 26 on plug 26, causing the tubes 22 and 24 (which, for the purposes of the invention, may be considered as a single continuous tube), to be moved longitudinally outward,

so that they will carry the needle valve away,

from its seat -on the end of the plu 12.

This movement will cause the valve 36 to be valve to be moved back toward its seat by the action of the spring 28 on the tube, 22. With the above described construction, when the engine is to be started,if the neepermitted past it when the throttle valve is nearly closed, it may or may not be necessary to open the throttle valve slightly be fore starting the engine, according to conditions. In any case these valves will perdle valve is adjusted so that a slight flow is r mit leakage to some extent' The air )rc'ssure in the portion ofthe carburete r casingdlrectly connected to the engine, will be immediately reduced, when the engine isturned over, so that atmospheric pressure on the surface of the fuel in the tank 18' will cause the fuel to be forced up through v the pipe 16 past the needle valve, and into the tube 22 and then through the screen 40 into the casing, to which it will be delivered in atomized form.

When the throttle valve is moved to increase the fuel supply to the engine, the needle valve will be correspondingly moved, so that, as the air is drawn past the throttle, it will be mixed with the atomized fuel, as it is discharged through the screen 10, the quantity of fuel discharged being determined by the adjustment of the needle valve.

As the fuel must pass through the screen 40 before it is delivered to the casing, all drops or globules of it will be broken up into a finely divided state, so that the air" and liquid will be thoroughly mixed, or the liquid will be effectively vaporized.

As the passage through the carburetor casing tapers, from the air inlet end to the port formed by rib 38, and then is gradually increased in size from said port, a. Venturi tube is formed thereby which inaterially augments the suction action of the engine at. the screened discharge. opening. so that the effective suction action of the engine is sufficient to cause the fuel demands of the engine to be met under all conditions,

the quantity delivered being determined by the adjustment of the needle valve.

\Vith the above described construction, not only is the volume of air drawn past the throttle valve varied accordingly to the extent to which it is opened, but the parts are so constructed that the extent to which'the needle valve is opened is also varied in coressary to produce an efiicient explosive mix ture, will be delivered to the 'carbureting chamber, in all open positions of the throttle valve. It will be obvious that thepitch of the cams and the relative sizes of the inlet and discharge ports are matters of design. For example, by varying the pitch oftthe cam at different points, the desired proportion of air and gas may be varied for different speeds, or extent ofopening of the throttle valv y All the advantages of a vacuum feed carbureter, as well as of an ordinary gravity feed carbureter, are thus secured, with the above described constructiom without many of the well known attendantdisadvantages of such devices. The present device ma es unnecessary the use of either a float valve or an air inlet check valve, both of which-re get out of order;

1. A carbureter comprising a casing having an air passage and .a liquid fuel supply passage leading thereto, a throttle valve for controlling said air passage, a stem for said valve, a needle valve extendinglongitudinally of said stein in position to control said fuel supply passage, and having a threaded connection with said stem, to permit adjustment thereof with relation to the stem, and means to cause simultaneous rotational and longitudinal'movement of said stem to move said throttle valve rotatably, to control said quire careful adjustment and are liable to air passage, and to move said-needle valve longitudinally to control said fuel supply passage in corresponding relation.

3.. A- carbureter comprisin 2. '-:A- carbureter comprising a casing hav-" ing an air passage, and'aflfuel supply passage opening to saidair passage, a throttle valve for controlling said air passage, a stem for said valve mounted for rotational and lon itudinal movementsinthe' casing, a ne e valve extending longitudinally of said stem in position to control said fuel sup ly passage, and having a threaded connection with w said stem to permit longitudinal adjustment thereof with relation to the 'stem, means to rotate said stem to control said throttle valve and means, including a cam, to, move said stem longitudinally in one direction or the other, according to the direction in which 'it is rotated, to move saidneedleyvalve in directions: to vary the fuel supply in pro portion to the extent to is varied.

ing anxair passage leading theret a tubular'stem-extendin'g transversely of said. passage and having a butterfly valve mounted thereon, =1 liquid fuel supply pipe having an alinement with said stem, a needle valve outlet opening into said casing, in axial axially disposed within said-stem in position to control the flow from said 'openlng and I having a threaded connection with said stem, to permit adJuStment thereimmeans to rotate said stem,and means, including a cam,

for moving said stem. longitudinally as'it is rotated to vary the air and fuel supply correspondingly.

In testimony whereof, I have signedmy 7 5 name to this'specification. THOMAS'W. onn.

Witness:

LOUIS H. H'ARRIMA'N.

which the airsupply I a casing haV- 69

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