US1553041A - Carburetor - Google Patents

Description

Sept. 8, 1925,.

J. HARRIS CARBURETOR Filed May 29, 1918 2 Sheets-Sheet Sept. 8, 1925.

J. HARRIS CARBURETOR 2 Sheets-Shae.

Patented Sept. 8, 1925.

UNITED STATES PATENT OFFICE.

OARBURETOR.

Application filed May 29, 1918. Serial No. 237,218.

To all whomc't may concern:

Be it known that I, JOHN HARRIS, a citizen of the United States, residing at Lakewood, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Carburetors, of which the following is a full, clear, and exact' description, reference being had to the accompanying drawings.

This invention relates to carburetors and has for its general object to improve the exficiency of such devices. Further and more limited objects of the invention are to provide a carburetor whereby the liability of reflux condensation in the intake manifolds is overcome; to provide a carburetor with means (conveniently adjustable) which will enable the engine to function with maxi- .mum efficiency at low or intermediate speeds as well as at high speed; also to provide a carburetor having efficient and conveniently operable means for starting in cold weather. I secure the foregoing objects and other objects which will appear hereinafter in and through the construction and arrangement of parts illustrated in the drawings forming part hereof wherein Fig. 1 represents a side elevation of a carburetor constructed in accordance with my invention, showing its arrangement with reference to and the manner of connecting the same with an intake manifold; Fig. 2 is a sectional plan View corresponding substantially to the line 2-2 of Fig. 1, certain parts being broken away; Fig. 3 a vertical sectional view corresponding substantially to the line 33 of Fig. 2; Figs. 4 and 5 similar views corresponding respectively to the lines 4-4 and 55 of Fig. 1; and Fig. 6 a sectional detail through the valve controlling the supply of liquid fuel to the mixing duct.

Describing by reference characters the various parts illustrated in the drawings, '1 denotes a float-feed chamber having a supply connection 2 provided with a valve seat 3 and a valve 4 operated from the float 5 by means of a lever 6 pivoted on a shaft 7, the lever being operatively connected to the valve at one end and to the float at its opposite end, as by means of a screw 8.

Projecting from the main body of the float chamber and forming part thereof is a chamber 10, communicating with the main port 10 The outer side of the chamber 10 is preferably rounded and has therein a tubular valve casing 11, the lower end whereof forms a tight connection with the bottom wall of the chamber from which a passageway 12' extends, said passageway communicating with a conduit 13 leading into the central portion of the mixing duct of the carburetor proper, being provided with a jet orifice 12% extending upwardly and located centrally within such duct. The valve casing 11 is held to the bottom wall of the chamber 10 by means of a plate 14,

plate having a threaded boss l P-proecting upwardly therefrom, said plate and boss having a bore therethrough for the. passage of the valve 15, which slidingly fits said boss and is adapted to be seated abdve the passageway 12. Extending upwardly from the bottom-of the valve casing is an elocrligatedslitdfi, preferably about .008 inch wi e.

The valve 15 is preferably provided by I one of the branches of a cylindrical 0d of an inverted U-shape, the. valve branch 15 extending upwardly through the casing 9, the upper end of said casing being capped to provide a bearing for a helical spring 17 the lower end whereof engages 'a collar proj ection 18 on said branch. The other branch 15 of the valve rod extends downwardly parallel with the branch 15 through a guide sleeve 19 carried by the chamber 10, its lower end being shown as engaging a lever arm 20 projecting from a rock shaft 21 journaled at one side of the bottom of the mixing chamher. The plate 14 is shown as secured to the top of the chamber 10 by means of screws 14.

Carried by and preferably cast with the float feed chamber is the portion of the carburetor wherein the liquid fuel from saidchamber is mixed in varying proportions with air. 22 denotes a cyllndrical mixing duct having a permanent air supply c0nslightly below the top thereof. portion of the float chamber through a wide Secured to a flange 22 at the top of the mixing duct is a duct section 24 which in turn supports a hollow head 25 having an auxiliary air connection 26 projecting upwardly therefrom and provided with a butterfly valve 27 mounted on a shaft 28 having an operating handle 29 which may be provided with suitable connections enabling the driver to operate the same, as occasion may require, to choke the air supply when starting the motor and to thin the mixture after the motor has been started. The head 25 is provided with a diaphragm 30 extending across the bottom thereof and provided with a pair of segmental ports 31 concentric with the center of said diaphragm, each port being controlled by a flutter valve 32, each having an arm 32 journaled on a shaft 33 mounted in a lateral extension 24 of the chamber 24, each arm being yieldingly carried by a helical spring 34 one end of which bears against said arm, the opposite end bearing against the bottom of a capped nut 35 threaded onto a nipple 36 depending from the bottom of such chamber extension. By adjusting the nuts 35, the tension of the springs 34 may be varied so that the flutter valves 32 may operate under different degrees of suction, or vacuum pro duced in the mixing duct by the motor. It will be noted that the capped nuts 35 are milled, and the milled surfaces of said nuts cooperate each with a spring-pressed plunger 35 mounted in a casing 3 5 depending from the bottom of the lateral extension 24*, said plunger-s serving to retain the said nuts in any postion to which they may be adjusted. By this arrangement one of these 'valves may be adjusted to secure the proper flow of auxiliary air for low and intermediate speeds while the other may be adjusted to come into play under higher speeds and hence under higher suction or vacuum conditions in the mixing duct.

The outlet connection 37 of the mixing duct is secured to a substantially horizontal connection 38 projecting from the intake manifold 39. Within the outlet connection 37 is the throttle valve 40, which is shown as of the usual butterfly type. This valve is mounted on a shaft 41 journaled in the connection 37 and said shaft is provided with an operating handle lever 42 rigid therewith, which handle lever may be connected in the usual manner to the accelerator pedal and the quadrant lever. Projecting from the pivotal portion of said handle lever is an internally threaded boss 43 which is adapted to receive a screw 44 having at one end thereof a milled head 44 adapted to be engaged by a spring-pressed locking plunger 45 in a casing 45 also carried by said lever. Below the boss 43 is an extension 46 in which a screw 47 is threaded, said screw being adapted to engage a lug 48 projecting upwardly from the flange 37 at the base of the connection 37 and thus provide an adjustable stop for limiting the closing movement of the throttle valve.

The shaft 21. is mounted in a tubular guide 21 carried by the connection 37 and has sleeved thereon a pair of angularly disposed arms, one of said arms 49 extending beneath and in operative relation to the screw 44 and the other arm 49 being in operative relation to an adjustable stop screw 50 and to the cam end of a lever 51 which is pivoted intermediate of its ends on a pin or shaft 52 projecting outwardly from the lower end of the connection 37. The stop screw 50 is similar to the screw 44, being threaded into a boss 53 projecting from and rigidly connected to the rock shaft 21, there being a spring-pressed plunger 54 cooperating with the milled head of said screw to retain the same in adjusted position.

Depending from the central portion of the diaphragm 30, and shown as secured thereto by a screw 55 is a stem 56 having at its lower end a conical air deflector 57 which surrounds the air discharge uotlet 23 and extends below the top of such outlet, forming a narrow annular passageway about such outlet and providing means whereby the entering auxiliary air may exert an aspirating effect upon the jet orifice without danger of passing into the permanent air supply duct 23.

lVith the parts constructed and arranged as described, the operation will be as follows: In starting, the auxiliary air valve will be in closed or choked position and the valve 15 will be opened through the portion of the handle lever 51 which extends above the shaft 52 engaging the arm 49 (this operation not affecting the throttle valve lever 42) to admit a large supply of liquid fuel to the conduit 13 and the jet orifice, which is particularly desirable in cold weather. The jet orifice 13 is substantially in the same plane as the liquid level maintained in the chamber 1, being preferably about 1/64 inch above such level, so that only a slight pull or suction of thmotor is necessary in order to draw the liquid fuel from said orifice. The motor having been started with the rich mixture, the lever 51 is released and the valve 27 opened as far as desirable, and the valve 15 operated from the accelerator or quadrant lever in conjunction with the throttle valve 40, through the lever 42 and screw 44 bearing upon the arm 49. This ensures a supply of liquid fuel to the jet orifice which is proportional to the throttle valve opening. The valve 27 being opened, the auxiliary air is supplied through its duct 26, 24 and through the valves 31 in accordance with the motor speed, one of said valves being operative at low and intermediate speeds and the other operating additionally at high speeds only. The auxiliary air entering through the valves 27 and 31 passes into the mixing duct, around the conicaldefiector 57 in a particularly efiicient and aspirating relation to the jet orifice, and a mixture corresponding in proportions and quantity to the throttle opening and the engine speed is supplied through the downwardly extending connection 37 and the horizontal connection 38 to the intake manifold 39. The arrangement of the jet orifice above the intake manifold, with the connections from said orifice extending downwardly to said manifold, enables the mixture to drop by gravity into the manifold, thus practically eliminating reflux condensation of the liquid constituent of such mixture in the manifold and enabling the motor to be started witha minimum consumption of time, as Well as at a minimum speed, sincepractically no lifting effect is necessary. to be exerted by the motor upon the jet orifice in order to insure a flow of liquid fuel therefrom to the mixing duct. In practice, the rock shaft 21 will be adjusted by the adjustable stop screw 50 that the lower end of the slit 16 will be uncovered for supplying liquid fuel to the engine while idling. The manner of connecting the valve and the throttle valve enable me conveniently to vary the throw ofthe former valve with reference to the latter so as to secure the proper amount of liquid fuel to the throttle valve opening of any particular installation. By means of the screw 50, the

positions of the arms 49 and 49* with refer-' ence to the arm may be varied, the screw 44 providing means whereby the throw of the rock shaft 21 (and hence of the Valve 15) may bevaried with reference to the throw of the arm 42 (and hence with reference to the movement of the valve Among the advantages which are secured in and through the use of my carburetor are the following i (a) Ease of startingparticularly in cold weather--due to the. convenience of supplying at this time an adequate amount of liquid fuel to the jet orifice, to the ease of drawing liquid from the jet orifice and a mixture of such liquid with air to the motor, and to the elimination of reflux condensation in the manifold. (b) A conveniently operable adjustable connection between the throttle valve and the liquid fuel supply valve, enabling'me to secure an adequate supnly of liquid fuel for starting purposes and thereafter to ensure an adequate supply of such fuel tional to the throttle valve opening.

(0) Conveniently operable, effective adjustable means for varying the flow of auxiliary air past the jet orifice in accord-' ance with the engine sneed.

propor- Having thus described my invention what I claim is:

1. In a carburetor, the combination of a feed chamber, a mixing duct, a conduit for liquid fuel extending from said chamber to said duct and having a jet orifice in said duct, an air supply conduit extending into said duct and having an upwardly extending discharge outlet surrounding said orifice, a valve controlling the supply of liquid fuel to the jet orifice, a throttle valve below said jet orifice, connections for operating the liquid supply valve from the throttle valve, means for operating the liquid supply valve independently of said connections, an auxiliary air supply duct communicating with the mixing duct above the jet orifice, valves controlling the supply of auxiliary air to the mixing duct in accordance with the suction or degree of vacuum therein, a conical deflector interposed between the last mentioned valves and the jet orifice and surrounding the upper end of the fixed air supply outlet, and a manually operated valve for controlling the supply of auxiliary" air to the last mentioned valves.

2. A carburetor comprising a vertically disposed mixing duct and a feed chamber, a

throttle valve positioned at the lower end of said duct, a permanent air supply conduit extending into the side of said duct and having its inner end extending upwardly, a liquid fuel conduit connecting said feed chamber with the upwardly extendin end of said air conduit, an auxiliary air evice disposed at the upper end of said mixin duct, means for regulating the amount 0 air admitted to said duct by said auxiliary air device, and a deflector positioned over the upwardly extending end ofsaid perma-' nentair conduit to prevent air from said auxiliary air device from entering said conduit. .T

- 3. A carburetor comprising a vertically disposed mixing duct and a feed chamber, a throttle valve positioned at the lower end of said duct, a permanent air connection and an auxiliary air device adapted to supply air to said duct in opposite directions, a liquid fuel conduit connecting said feedchamber and said mixing duct and ada ted to supply fuel to said duct,- the. end 0 said conduit connectin said mixing duct terminating in a jet ori ee disposed at. substantiallythe same level as the liquid level in said feed chamber, and a valve interposed in said liquid fuel conduit, said valve being so arranged as to operate in unison with said throttle valve or independent thereof. 3

' In testimony whereof, I hereuntoaflix my signature.

JOHN HARRIS.

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