US1559756A - Carburetor - Google Patents

Description

) 1,559,755 w. s. KEMP v QARBURETOR F11 July 1922 3 sheets-Sheet 1 INVENTOR ATTORNEY W. E. KEMP QARBUREJTOR Nov. 3, 1925. 1,559,756-

Filed July 1. 1922' s Sheets-Shani 2 INV EN TOR A TTORNEY v Nov. 3, 1925- W. E. KEMP.

CARBURETOR Filed July 1, 1922 s shuts-Sheet s INVENTOR W1 1.. BY

ATTORNEY Patented Nov. 3, 1925.

' UNITED STA WILLIAM E. KEMP, OF NEW YORK, N. Y.

. CARBURETOB.

Application filed July 1,

To all 107mm it may concern:

Be it known that I. WILLIAM E. KEMP, a citizen'of the United States, and resident of the city of ,New Yo1-k, in the county of New York and State of New York, have invented certain new and useful Improve? ments in Carburetors, of which the following is a specification. I v

The present invention relates to improvements in carburetors and more particularly to that class in which the liquid fuel is lift-.

connected to the valve consists of a 'dia-Q phragm, one face of which is exposed to atmospheric pressure, while its other ,face is subjected to the vacuum in the'carbureting chamber, the arrangement being such that o the valve opening is in inverse proportion to the vacuum produced in the carburetiug chamber. In other words, the higher the Vacuum, the smaller the nozzle opening, and the lower the vacuum, the larger the nozzle 5 opening. In practice it has been found however, that these constructions are impracticable for variable speed e'ngines,,the reason being that, as the throttle is shifted to its closing position and approaches the end of its closingstroke, the vacuum in the carbureting chamber gradually decreases instead of increasing, as theoretically should be the case. The result of thisis that the valve controlling the nozzle automatically 45 increases the nozzle opening, whereby a too rich mixture is produced. I

- The main ob'ect of the present invention is to overcome this defect, or in other words produce a carburetor wherein the proper roportion of air and liquid hydrocarbon I 1s obtained during the entire range of the throttle movement thereof.

V A further object of the invention is to provide a carburetor in the nozzle of which 1922. Serial No. 572,235.

constantly a vacuum of predetermined degree is produced, irrespective of the changes of the vacuum in the ca'rbureting chamber.

With these and other objects inview,

which will more fully appear as the nature of the invention is better understood, the same consists'in the combination, arrangement and construction of parts hereinafter described, pointed out in the appendedclaims and illustrated in the accompanying drawings, it being understood that many changes may be made in the size and proportion of the several parts and details of construction within the scope of the appended claims, without departing from the spirit or sacrificing any of the advantages of the invention.

One of the many possible embodiments of the. invention is illustrated in the accompanyi'ng drawings. in which Figure 1 is a central vertical section taken through a carburetor constructed in accordance with the present invention; Fig. 2 is j a section taken on line 22 of Fig. 1;. Fig.

is a top plan "iew of the carburetor, Fig.v 4 is a diagram illustrating the relation between the throttle openings and vacuum in the carbureting-chamber; and Fig. 5 is a diagram of'a cam controlling the nozzle opening of the carburetor.

Referring now to the drawings, the carburetor comprises a carbureting chamber 10. in the form of a tubular body, provided with a flange 11, which abuts against the engine intake. The outer 'end of the car bureting chamber is, preferably, flared, as shown at 13 to permit of .an unrestricted flow of air into the carbureting chamber. The chamber 10 is provided intermediate its ends with a nipple 14, to which is joined, by a suitable coupling, a pipe 15, the latter leading toa fuel tank below the carburetor.

Into the nipple fits anozzle 16, extending diametrically across the carbureti-ng cham-' her. This nozzle is provided with ongitudinal'slots 17, disposed on that sideof the nozzle which faces the outlet of the carbureting chamber. The purpose of this arrangement vwill be hereinafter explained. The nozzle is provided below its slots with a restricted opening 18 with which co-operates a needle valve 19, which is disposed within the nozzle, its diameter bein smaller than the inner diameter of sai nozzle.

Outside of the carbureting chamber, the

needle valve is reduced in diameter, as shown at 20, thisreduced end being tightly fitted into a bore 21 infan exteriorly screwthreaded stem 22. With the threads of this stem mesh those of 'a sleeve 23, on the lower end of which is mounted a diaphragm 24- of any suitable construction, the

sleeve 23 bears'astar-shaped spring 28 in ed to the vacuum in the carbureting cham-,

the cylindrical extension 27, the tendency of this spring being to lift the needle valve. The under-face of the diaphragm is subjectber, the latter communicating through an opening 29 with that portion of the' cylin: drical extension 27 which is disposed below the'diaphragm. The upper face of the diaphragm, on the other hand, is exposed to atmospheric pressure. atmospheric air finding its way to the said upper face through an opening 30 in the member 26.

To permit of an adjustment of the fuel valve there is fixed to the stem 22 'a disk 31, having notches 32 in diametrically opposite portions thereof. In these notches are seated prongs 33, fixed to a spindle 34, the latter; being rotatably mounted upon a cover 35, which closes the cylindrical extension 27 of the carbureting chamber. The

free end of the spindle 34 carries'an arm 36 for connection with an operating rod,

which permits the needle valve to be adjusted "from a distant point. A'spring 37, coiled around the spindle 34, is interposed between the cover 35 and arm 36, its pur-- pose being to hold the needle valve in any adjusted position in relation to the sleeve 23. In front of the needle valve is located a butterfly throttle 38, the spindle 39 of which extends in parallel relation to the needle valve, alever'40, fixed to the lower end of the spindle 39 and having its other end connected with an actuating rod, not shown, being provided for operating the throttle.

To the upper end of the spindle 39 is rigidly attached a cam 41, co-operating with an arm 42, which is riveted or otherwise attached to a blade spring 43, the latter being clamped to the cylindrical extension 27.

Against the lower end of theupwardly bent portion projecting,

overcome the pressure exerted by the spring 28, for a purpose hereinafter to be explained.

- From an inspection of the drawings it appears that the only restriction or obstruc tion to the flow of air through the carbureting chamber is by the throttle. It also ap-, pears that there is no restriction in the car bureting chamber between the nozzle and the engine, or in other words there is no 0bstruction placed in the path of the fuel. Due to this construction, the highest vacuum or .lowest pressure point in the carbureting chamber is immediately in rear of the throttle. The nozzle, on the other hand, is within the range of the highest vacuum or lowest pressure point.

In. order to understand the operation of the elements so far described, reference is first made tothe diagram shown in Fig. 4 of the drawings In this figure the, line .A-X represents the axis of abscissae, and the line A--Y "the axis of ordinates, the

abscissa: representing the throttle openings l vacuum in the carbureting chamber, said vacuum increasing gradually to the point I at which the throttle is about 20 from its closing position. Then. there is a turn in this curve, the vacuum gradually decreasing when the throttle is fully closed. Theoreti rally there should be no turn in the vacuum curve, as the vacuum should be the highest in the carbureting chamber when the throttie is' fully closed. If, therefore, the needle valve were controlled by the vacuum in the Jim carbure'ting chamber, it would gradually close the discharge opening of the fuel conduit as the vacuum in the carbureting chamber increases up to a point in the closing movement of the throttle corresponding to the point I in the vacuum curve A(). At this point the valve would then gradually increase the discharge opening of the fuel conduit and would thus, during a turn of 20 at the end of the closing movement of the throttle, produce an over-rich mixture.-

ln order to prevent this, a connection is made between the throttle and needle valve, as above described, the cam 41, shown diagrammatically in.Fig.-5 of the drawings, being so constructed that the spring-pressed arm 42 cannot act on the sleeve-45 until it reaches. the point C (Fig. 5) of the cam, the

cam face between the points C and C being so constructed that it holds the spring- "Ind pressed arm 42 in an elevated position. From the point C to the point C the cam face gradually slants, permitting the spring pressed arm 42 to act on the sleeve 45', and thus on the diaphragm 24, the result being that during. the last 20 of the closing movement 'of the throttle the needle valve '19 gradually obstructs the discharge opening,

of the liquid fuel conduit, mixture is provided. v v

Bearing these facts in mind, it will be found that the operation of the carburetor is whereby a proper as follows: The suction of the engine lifts,

liquid fuel from thetank against the 'force of gravity into the nozzle, and the, air, which is caused to flow in a confined stream through the carbureting'chamber' past the discharge end of the nozzle, entrains and vaporizes the liquid fuel, the'resultlng combustiblemixture being drawn into the cylinder. A lifting of the fuel is made possible by the fact that the nozzle is subject to the highest vacuum created by the 'siictiomof' the piston, irrespective of'the speed of and load to the engine. The slots 17 are disposed in that side of the nozzle 16 which faces the outlet opening ofthe carbureting chamber, to produce a homogeneous mix-' ture of air and cdmbustible;-gas, the,liquid fuel being discharged at rightangles to the flow of the air through the carbureting chamber and the air not striking directly the liquid within thenozzle. By reason of this construction, the sensibility of the needle valve is eliminated to a great extent.

Another purpose of disposing the slots in -the manner above stated is to produce a higher vacuum within the nozzle. (By reason i of this higher vacuum a faster nozzle dis-1 charge 'is induced, thereby causing finer chamber. Each charge is therefore of the. same quality with a given throttle opening,

resulting in an even running of the en- In a s ngle cylinder engine,' when the throttle is'shifted, during the suction stroke of the piston inthe cylinder, within a range ofbet'ween 20 and toward closing positiom'theneedle valve is lowered, because the; vacuum in the carbureting chamber acts upon the underface of the dia hragm 24. The opening 18 in thenozzleis t us'restricted, the degree of restriction depending upon the" vacuum in the'said chamber. Immedi- 'ately after the suction stroke, the needle valve returns to its normal position under the action of the spring 28. The lowering of the needle valve is due to the difference,

of pressure on the underface and the upperface of the diaphragm 24. The purpose of.

this arrangement is as follows: It provides automatic means, within the range mere tioned, for regulating the dlscharge open:

ving- 18 of the fuel conduit, the valve rcstricting during the suction stroke of the piston the said discharge opening in .pro; portion, to the speed of the engine. Within this range the spring 43 does not. act upon the diaphragm, the arm 42 being held by the cam 41 in positions so as not to act upon.

the needle valve, During the movement'of the throttle from the zero to the 20 position, the cam permits the spring 43 to act upon the needle valve regardless of whether the movement of the throttle is in the, opening or closing direction. The. needle valve restricts thereby the discharge end of the fuel conduit according to the position of the throttle, or in otherwords in propor- 'tion to the vacuumin the car-bursting chamber., From the foregoing it appears that the needle valve opens in inverse proportion to the vacuum throughout the entire. range ofthe movement of the throttle, part of the movement of the needle 'valvebeing automatic and part positive. In multi-cylinder engines the moving parts of the device, due to inertia, do not follow the pulsations of the vacuum, but assume a mean position.

From the foregoing it will be seen that the liquid fuel is drawn into the carbureting chamber, instead of being forced in. Possibility of flooding the apparatus'is thusremoved, as no liquid fuel can be introduced into the same except by the suction of the engine, which at once vaporizes the liquid fuel. In case of accident or stopping of the engine, the liquid fuel in-the supply pipe 15 immediately returns by gravity into the'tank.

The point I of the curve shown in Fig.'

4 of the drawings depends onthe condition of the internal combustion engine with reference to .valves, piston and piston ring fits. In engines in which these parts are. in excellent mechanical condition the point I of the' curve is nearer the axis A--Y of ordinates-than in motors which are only in average mechanical condition. In some cases the pointI has been found to be very near the ordinate marked 10 in Fig. 4 of the drawings. In others it is at 15 and still in others at. 20, as shown inthe said figure. I

In the construction .so far described, the

vacuum in the nozzle 16 is somewhat greater than the vacuum in the carbureting cham her at approximately wide open throttle.

ner face of the valve casing.

.to the nozzle. results.

valve 48 Within a valve casing mined degree.

As this vacuum in the carburetin chamber varies during the operation of t e engine, obviously an uneven flow of liquid fuel in- In order to prevent this, an air passage 47 leads to the nozzle, said passage being controlled by a Weighted 49. The valve may be of any suit-able construction. In the case illustrated it includes a stem 50, having a pointed 'end 51, controlling the inlet to the passage 47. On the stem are provided guides 52, bearing against the in- The Weight of the valve is overcome by the suction in the nozzle 16, it being lifted from its seat whenever the suction exceeds a, predeternozzle'16 acts as an unvented nozzle until a suflicient vacuum is reached to 'unseat the valve 48. After" this, even though the vacuum in the mixing chamber may materiallyincrease, the vacuum in the nozzle will remain substantially constant, being that reuired to unseat the valve. The result of t is is that an even flow of liquid fuel is induced into the nozzle.

When starting an engine, the throttle 38 is shifted to closing position and the arm 42 lifted by the actuating rod, connected to the upwardly bent, portion 42, whereby the spring 28 lifts the needle valve, thereby permitting of a priming of the carburetor. As soon as the engine is running, the

arm 42 is released and the throttle actuated according to the requirements.

What I claim is: I

"1. A carburetor comprising a carbureting chamber, a supply nozzle therein, a

valve controlling said nozzle freely mov- 21st day of J une, A. D, 1922.

able in relation thereto, a throttle in said carbureting chamber, means connected with With this arrangement, the I said valve for automatically adjusting said nozzle in proportion 'to the ,vacuum produced in said carbureting chamber during a predetermined portion of the stroke of said throttle, and means controlled by said throttle for mechanically actuating said valve during the remainder of the stroke of said throttle. 1

2. A carburetor comprising a carbureting chamber, a supply nozzle therein, a valve controlling said nozzle freely 'movable in relation thereto, a throttle in said carbureting chamber, a diaphragm con nected with said valve under the action of the vacuum in said carbureting chamber for automatically adjusting said nozzle in proportion to the vacuum produced in said carbureting chamber during a predetermined portion of thestroke of said throttle,

and means controlled by said throttle for mechanically actuating said valve during the remainder of the stroke of said thrott e.

3. A carburetor comprising a carbureting chamber having an air inlet and a mixture outlet, a fuel nozzle dischargin in said chamber, a valve controlling said nozzle, means constantly acting to open said valve, means responsive to the depression in said carbureting chamber acting to close said valve, a throttle valve for said carbureting chamber, and a second means to close said fuel valve, held out of operation by said throttle valve during a portion of the movement thereof, and free to operate during the remainder of the movement of said throttle valve. I

Signed at New York, in the county of New York, and State of- New York, this WILLIA E, KEMP.

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