US1787534A - Carburetor - Google Patents

Description

Patented Jan. 6, y1931 ,UNITED STATES PATENT 1 om@ j I oIIAnLEs'II. meer Ann FREDERICK rUItDY, ory FLIN'I, MICHIGAN, AssIGNons rro MARVEL CABBURETER coivIrANY, or FLINT, ,IvIIorIIeAN, ,A CORPORATION or ILLINOIS y cAnBUnETon Application mea september? r2, reas. sei-iai no. 305,523.

This invention relates to improvements Vin carburetors of the character used for furnishing explosive mixtures to( internal combustion engines. v j l The primary object 4of the invention' is toV furnish'a carburetor of the` Venturi throat type With adjustablemeansfor creating va` riable depression communicating With the fuel feeding device or devices. f A

Another objectof the invention'is to provide a carburetor `Venturi throat having an opening inits entrance lip, and a ported rotatable' member cooperating vvithl said opening to create a depression in a chamber or passageway communicating with the fuel feeding device or devices; said ported member being adjustable for varying the degree of vacuum.

It has heretofore been proposed to provide a carburetor With a plurality of fuel feeding passagevvays, one communicating with the mixture conduit, posterior to the throttle valve, and the other formed by the main noz` zle 'of the carburetor. Such passagevvays communicating with an opening in the entrance lip of the Venturi tube or throat', and

consequently When the throttle is moving toward open position, the velocity of tlieair ilotvingthrough the venturi Will be increased,

with the result that the vacuum created through thevopening inthe entering lip of the venturi will be increased, to retard the flow of fuel-through said'passagevvaysQp-l'n such construction', a relatively small stream of fuel is discharged into the mixture pasvsagevvay above the throttle, which dischargeV is variable With relation to the position of the throttle,but does not cease altogether in 40 any positionr 0f the"thr `j ttle..v This stream is mingled with that of the main nozzle vvhen the'v throttle is open to any'eXtent, andv itdimini-shes as the discharge of the main nozzle increases; being AInodiiiedin its eXtent by a slightly sub-atmospheric pressure in a chamber communicating with the vstream passage- Way; this sub-atmospheric pressure being due to theposition of the opening or port in the entering lip of the Venturi sleeve,"and its iniuence being greater as or vacuum in chambersH the velocity of the air enteringv the Venturi sleeve is increased. It 1s a further object ofv this invention Vto improve carburetors of the last mentioned type by elongating the port in' the entrance lip of the venturi, and extending a rotatable sleeve vWith a smaller port therein, yinto the venturi, in lsuch a Way that the sleeve forms aportion of the surface ofthe entering lip ofthe venturi', As the ported sleeve may be turned for adjustment purposes, the port of the latter may be shifted toward 'or away from the lovver edge of the venturi7 and in this Way, the suctionsexerted through the' ported sleeve may be varied. f l Y A. further object is to furnish a construction of this character in which the radius of the entering lip of the venturiV is the same as the radius of the Aported tube, whereby the tube in shifting aroundfthe lip radius, may place its port invarious angular positionsto influencetheoperating depression.

With the above objects and vvith other objects in vievv Which Will appear as the descrip* tion proceeds, the invention consists in the novel features hereinafter described in detail, illustrated in the accompanying drawing, and more particularly pointed out in the appended claims.

Referring to the drawing,`

Figljis a vertical sectional vievv of an embodiment of a carburetor devised especially to'facilitate the disclosure of the invention, and showing the relative fuel levels in the various nozzles or stand pipes, When the throttle is in fully closed position.

Fig. 2 is a horizontal sectional view, on line 2`2 of Fig. 1.'

Fig. 3 is an elevation, partly in vertical section, of a detail, indicating the manner ofy placing the adjustable port of the venturi in communication with the chambers to be subjected to sub-atmospheric pressure.

Fig. lis a vertical sectional View, taken on taken ylinel--l of Fig. 3.

Whilethe invention has been illustrated in 'connection With a carburetor of a particular type, it Will be obvious Vthat it may be embodied in carburetors of various types, or in any rcaburetor Where it is desired to utilize the velocity of air flowing through a venturi to create'variable sub-atmospheric pressure in a chamber. for modifying or controlling the i V`iiow of fuel or the like.

. In thedrawing, it'will be noted that the fuel is fed from any suitable float tank 1, directly` to a tube 2, having,a-nozzle'g3,gthrough which 'a fine stream is fed into an Vannular chamber 4, the outlet 5 Iof which is controlled by a needlevalve 6. vThis fuel constantly flows through a duct 7, under suction iniiuence exerted in the carburetor outlet 8. The

duct 7 opens intothis passageway or outlet,

y posterior tol the throttle valve 9, and conse- 15, and an auxiliary nozzle 16 u quently, fuel will be continuously fed through 2 and 7, due to suction from the engine.

Fuel from thefloat tank, alsojlows through an orifice member 10, and by this means, in regulated quantity, enters a passageway 11, fromy which itliows throughV another orifice member 12, into a U-shaped conduit 13.. A

needle valve Aor the like 14, controls the flow to the U-shaped conduit,l and the armsof this conduit communicate with the main nozzle 5 the latter being located within achamber 17. Y

The main nozzle outlet terminates within a lVenturi sleeve 18, located in themixture passageway, as is usual in some ,typesof carburetors. v A port 19 is located in the entrance lip of the Venturi sleeve, and in a construction heretofore proposed, suchV port communicated` by a ,passageway 2O with the chamber 17, as well as with a chamber 21, in which thewtube 2 is located. Due to sucharrangethan the tube 16, vwhereby under acceleration,

when themain 'fuel nozzlebegins to draw on the auxiliary supply,it will first empty the nozzle 16, and afterwards, the well 23, 'such emptying being'brought about during the movement of the throttle from closed to fully opened position.

The present invention pertains to improvements in the means for placing the port 19 in communication with the passageway 20. In the construction heretofore proposed, there was no means for varying the :position of theA port 19 relatively to the entrance lip of the venturi, and consequently, the suction iniiuences `would always 'bethe same under given conditions. lVith the vpresent invention, the opening in the Venturi lip may be shifted in'order'that the angular position of tion :of the and, is provided at main nozzle is in-V this hole may influence the operating depression. To this end, acylindrical-bore is out through the bodyfof the carburetor, and Venturi tube 18, and the periphery of this bore coincides with the curvature of the entrancelip of the venturi. In this bore, a cylindrical sleeve 31 is placed, having a radius the same as the radius of the entrance lip of the'rventuri, so thatan intermediate p0rperiphery 4of the tube extends opening`19.l A relatively small through the aperture 32 extends through the cylindrical wall of the tube, on a line coinciding with the elongated opening 19, whereby when Vthe tube i's rotated, the aperture 32 will be shifted t0- ward orgaway'from the lower edge of the venturi. Y f

Some suitable'means mustbe provided to place the interior of the tube 31 in communication with the passageway 20, and one expedient for this i purpose is shown inthe drawing. vIt consists of a U-shapedpipe 33 having onecf its ends extending into the tube 31,`and its :other end extending into a duct 34 which communicates with 'the passageway 20;

For the purpose of shifting the tube 31, it Y is-provided with astem or shaft 35 which extends through the wall of the carburetor, its outer end with .a hand 36 that is fast on the shaft and design-ed to cooperate with 'a suitable scale formed on an indicator plate37 that is secured to one side of the carburetor in afstationaryl manner. for instance, by means of a screw 38. l

'ico

From the foregoing, it may be seen that the 'I discharge through 7 will vary as the'throttle 9-moves, but will not cease altogether in any positionY of the throttle. IVhen the throttle is fully closed, the supply through 7 will be at a maximum, butas the throttle opens, this ,supply will befdiminished. As before stated, it diminishes as .the discharge from the main nozzle increases, and it is modified inV its extent by `lightly:sub-atmospheric pressure in the ychamber 21, due to the'position of the aperture-32 in the entering lip of the Venturi sleeve. i This sub-atmospheric iniiuence is greater as the velocityof the air entering the venturi is increased, but it is f;

obviousthatsuch'iniiuence may be varied by turning the tube 31, so as to raise Vor lower the aperture 32.

Instant acceleration in the type of carburetor illustrated, is vobtained by the 'U-tube, made up of the nozzle 15, standpipe 16, and passageway 13; the fuel dischargeratebeing modified by the vdepression or sub-atmospheric 'pressurein the passageway 20,"so

thattlie higher the speed of the motor, th-e e less the additional tionpurposes. v

The well 2,3 is'for the double purpose of prolonging the accelerating charge, and for thinning out the mixture at high speeds.

discharge for Vaccelera- IDE readily understood from the foregoing Y scription when read in connection With the acoompanying drawing, and it is obvious that various changes may be made inthe details disclosed, Without departing from the spirit of the invention, asexpressed in the claims. What We claim and desire to secure by Letter-s Patent is: l. In a carburetor having a main passage- Way controlled by a throttle valve, a Venturi throat in said passa`geway,an opening in the` entrance lip of the Venturi throat, a ported member movably mounted relatively to the Venturi throat and having its port arranged to register With and opening 1n shift relatively to the the entering lip ofthe pressure, and means placing the port of the 'ported member in communication with said chamber.

2. In a carburetor, .a Venturi throat having an opening in its entrance lip, a shiftable member extending into a Wall of said throat and having a curved Wall provided With a port shiftable relatively to the opening in the entrance lip of the venturi When said member is turning, a chamber to be subjected to sub-atmospheric pressure, and means placing the chamber in communication Withsaid port.

3. In a carburetor, a Venturi throat having a curved entrance lip provided With an opening, a turnable cylindrical member extending into a Wall of the Venturi throat, and having a ported portion extending through said opening, a chamber to besub- .iected to sub-atmospheric pressure,v and means placing said chamber in communicay tion With said port.

4;. In a carburetor, a Venturi throat having a curved entrance lip provided With an opening, a cylindrical tube rotatably mounted in the Venturi throat and having a ported portion extending through said opening, the f for indicating exteriorly of the carburetor,

a chamber to be subthe position of the port, jected to sub-atmospheric pressure, and means placing said chamber in communication with the interior of said tube. v

In testimony whereof We hereunto aliix our signatures.

CHARLES H. KIRBY. FREDERICK PURDY.

venturi, achamber to be subjected to sub-atmospheric

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