US1534808A - Carburetor - Google Patents

Description

April 21,1925. 1,534,808

H. G. RENNER CARBURETOR Filed March 18, 1922 briefly', the

Patented Apr.. 21, `1925.

PATENTwoFFlcE.

' .'IAnoLD G. annuali, or DETROIT, MCHIGAN.

CARBURETOR.

\ appncannmea umn 18,3322. serial no. 544,765.

To all fic/wm z'tmoj/ concern: t

Be it known that I, HAROLD-G RliNNjsR; a subject of the King of Great" Britain, re sidin at Detroit, in the county of ;W ayne ATand useful Garburetor, of which the following is a specification: y

This inven len relates-to,carburetors for internal 'combustion engines, and particularly to the fuel 'feed control of such 'carburetors v The invention has for its object the prof, vision of means for effecting a temporary 1ncrease in the quantity of fuel delivered to the carburetor simultaneously with the open ing' of the throttle to accelerate the engine, and to.,automatically clfect the cutting off of such "increase within a predetermined time intervalxof action independently of a return enclosing/movement of saidthrottl. The inventi iis especially designed and adapted for a lcation to carburetors ofthe type-disclose 1n. my patent iwssuedSept. 12, 1922, No 1,428,558.` L,

The present- .invention contemplates, employment in'. connection with means controlled b the throttle. ,for adjustin a primary uel valve inthe outlet of a nel nozzle,'of a reciprocal piston .operativein'the manner of'a dash-pot in the fuel chamber ofsaid nozzlejand having` a valve stem normally seated in and closlng a secondary fuel outlet formed through said primary valve, said pistonbeing urged by a spring toward said primary valve ivn the 'opening direction thereof, but, being restrained against following said valve under abrupt or/rapid movement thereof in such direction, by the retarding action of the liquid, fuel displaced by movementof said piston vunder influence of said spring, hence a sudden opening movement of the 'primary valve willicause a momentary/or time limited opening of the secondary fuel inenting the primary jet 1n supp ying fuel.

' The duration of actidn of the secondary fuel ondary valve .stem to its seat in the needle supply will be determined by the speed of travelv of the piston in advancing the secvalve and this will bev governed b the clearance provided for the passage o the liquid fuel around the piston.

A preferred embodiment of the invention is hereinafter described and illustrated in the accompanying drawing, wherein,

,i y invention. nd tate oMichigan, have invented afnew Y buretor and 2 the air -1`n-let thereof "Fig. 1 is a vertical section longitudinally intersecting the mixing chamber and its air inlet of a carburetor embodying the present QF ig. 2 is an enlarged cross section on line 2-2 of Fig 1, showinga partially opened position, of the automatic air and fuel valves. In these views the reference, character 1 designates the mixin `ehanber'of the car- 'the same together forming `a"continuous horizontal passage. A'lap valve 3 ispivoted upon a pin 4 in the upper.` portion of said passage, and under idling conditions extends diagoi'ally across the'fpassage in the direction of the low \therethrough," as shown in full lines in Fig. 1.- The relatively small current of air which is delivered to the mixing chamber under idling kcondi-tions does not exert sufficient pressure Nupon said valve to overcome the weight thereof.k When, however, the throttle is adjusted to permit an increased flow, as when the engine is under load, the resultant air pressure rocks the valveiB upwardly through angle prolportionate to the increase of flow.. Itis preferred toform. the top of the carburetor casing with an, upward extension or domex, which will'aceommodate the valve 3 in its position of'maxix'num eleva-tion. The cen tral portion 6- of. the"v valve forms an arch extending v with ,gradually increasin height from. the pivotal extremity to the free end y chamber 7 is formed in an inte'gral, extension 7. of the carburetor casing beneath the same' and inclined at aslight angle from. the `vertical in the direction 'of flow through the mixingchamber. A piston 8 is mounted in said dash-pot chamber and is upwardly `urged by a coiled spring 9 seatl'ed in a cap 9 closing the end of said cham# bered extension, `said piston 'havingI a guide ange 10`spz'iced from the head 11 thereof, the latter having a slight clearance fromthe wall of thechamber 7, and the former having apertures 12 forthe passage of li uid past said piston'. Liquid fuel is admitte to the chamber 7 at a point between the piston extremities 10 and 11 throughl a port 13 openincr from a 4passage 1,4 leading from a float c amber 15 or other suitable source of suppl A'ball check v'alve 15 seats-,centrally withn'the piston 8, closing a' ley-pass 15b through the-head 11 when thepiston is Cil rising but lifting therefrom upon downward movement of the piston to permit the liquid below the head 11 to flow freely vthrough said b v-pass and thus relieve the piston from thc resistance such as is set up by the displacement of the liquid through the clearance around the piston head as occurs in the rising movement thereof.

A passage 16 primarily providing for a delivery of liquid fuel from the chamber .7 to the mixing chamber, opens into the latter beneath the free end of the air valve 3. Said passage iscontrolled by a primary fuel valve 17, which is formed with a secondary fuel feed passage 18, therethrough under control of a valve formed by the rounded upper end of a stem 19, integrally rising from the piston 8. The valve 17 is carried by the free end of a rockearm, comprising a strip of sheet metal 2O extending through the arch of the valve 3 and a leaf .spring 21 secured to the other end of said strip and attached by a screw 22 to the top face of the air inlet adjacent the mouth thereof. The connection between said spring and strip may be established by brazing, soldering, or in any other suitable manner. Said spring is stressed toiurge the rock-arm 2O upwardly, but not with sufficient force to overcome the weight of the valve 3, which acts upon the rock-arm through a block 23 apertured to engage the rock-arm and having its top rounded to bear upon a plate 24: carried by said valve. The block 23 is adjustable longitudinally of the rock-arm 2O by means of a bar 24, arranged beneath said strip and secured at one end to said block. The other end portion of said bar forms a rack 25engaged by a pinion 26 fast upon a shaft 27 adjacent the spring 21. Said shaft mayfhave an end portion (not shown) projecting exteriorly of the carburetor casing and rotatively act-uable by any suitable means. At 2S is indicated the usual throttle member controlling the outlet from the mixing chamber.

Considering now the operation of the described farburetor, it is to be understood that under idling conditions the valve 3 rests upon the floor of the passage 1, 2, and that the primary fuel valve 17 remains slightly raised from its seat allowing a flow of air and fuel through the comparatively restricted passage formed by the arch member G. When the throttle 28 is opened more or less, there is a corresponding increase in the flow of air into the mixing chamber, and under such conditions, the valve 3 is rocked upwardly by the pressure of air, as for eX- ample, to the position indicated in dash lines in Fig. 1. Such movement of the valve 3 permits the rock-arm 20-21 to likewise,

swing upwardly responsive to the effort of` the spring 21, and consequently the primary fuel valve 17 is withdrawn from the fuel passage 1G to an extent determined b v the angle through which the valve 3 and said rock-arm have been shifted. Under the up! ward effort exerted by the springn) upon the piston S and valve 19, the latter tends to follow the primary valve 17 as the latter is raised from its seat, but owing to the retarding effect of the dash-pot the valve 19 is restrained from immediately following the primary valve when the opening movement of the latter is abrupt or rapid. Consequently, under such conditions the seeondary fuel passage 18 is opened and the mixture is enriched by the supplementary delivery of fuel through said passage. lf, however, the opening movement of the primary fuel valve is gradual the retarding effect of the dash-pot will not be sufficient to prevent the secondary valve immediately following the primary valve in the opening movement of the latter, thus preventing opening of the secondary fuel passage and the issuance of fuel therfrom.

It will be noted that the functioning of the secondary fuel valve is not dependent upon the specific means disclosed for operatin the primary fuel valve, but that said secon ary valve will readily function as described in connection with an apertured fuel valve actuated by any suitable means.

What I claim is:

1. A carburetor comprising a mixing chamber, a valve controlling a primary fuel supplywto said chamber,r said valve having a passage for a secondary fuel supply, a secondary valve normally seating upon the primary control valve to close said passage, means urging said secondary valve to its seat, tending to maintain said passage closed during the opening movement of the primary val-ve, and means retarding the move ment of the secondary valve in the direction of'opening of the primary valve.

2. A carburetor comprising a mixing chamber, a valve controlling a primary liquid'fuel inlet to said chamber, said valve being formed with a secondary fuel inlet `substantially co-axial with the primary inlet, a secondary valve normally seating upon the primary valve toclose said inlet there- 115 in, a spring normally ,urging said secondary valve to its seat, tending to maintain the seeondary inlet closed during opening of the primary valve, and means retarding the increment of the secondary valve in the direction of opening of the primary valve.

3. A carburetor, comprising a mixing chamber, 'a valve controlling a primary liquid fuel inlet to said chamber, said valve being formed with a secondary liquid fuel inlet, a follower valve seating upon. the'irst mentioned valve oppositely to the direction of seat-ing of the latter and controlling said secondary fuel inlet, a spring urging said follower valve to its seat in the direction 13o of opening of the primary valve, and 'a dash. 5. In a carburetor, e casing having e, miie 20 pot retarding the seating movement of said follower valve.

el. A carburetor, comprising a' mixing chamber, a valve controlling e primary liquid fuel inlet to said chamber, said valve beingforined with e 'secondary liquid fuel inlet, u follower vulve seating upon the first mentioned vvalue oppositely to the direction. of seating of the latter und controlling said secondary inlet, e 'piston connected Ato said follower ,\f'ulve, a' liquid fuel chamber in which Suid 'piston operates as a dash pot to retard seating of the follower valve, Suid chamber communicating with said primary ing chamber, and formed with un air inlet and' e primary liquid fuelinlet to seid chunk lier, e valve controlling said air inlet respon sive to air pressure, a primary valve controlling said liquid fuel inlet, and urged to its seat by said air valve in closed position of the latter, said primary valve being formed with a secondary fuel inlet, a seo ondary fuel valve seating upon the primary valve in the direction of opening tloereoil und controlling said secondary inlet, Ineensurging said secondary valve to follow the primary valve when the latter is unseated, and means 'for rtarding such following movement of the secondary valve.

In testimony whereof I sign this specification.

HAROLD G. RENNER.

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