US2042770A - Carburetor - Google Patents

Description

M. E. CHANDLER CARBURETOR June 2, 1936.

Filed May 7, 1932 2 Sheets-Sheet 1 Il I INVENTOR. /17//20/7 t'. band/er a.' Q gw ATTORNEY June 2, 1936. I M. E. CHANDLER CARBURETOR Filed May '7, 1932 2 Sheets-Sheet 2 INVENToR. Mi/on E. Chand/er m27. Q

ATTORNEY Patented June 2, 1936 UNITED STATES PATENT OFFICE CARBURETOR Application May 7, 1932, Serial No. 609,931

Claims.

This invention relates to charge forming devices and more particularly to carburetors for internal combustion engines.

An object of the invention is to provide a carbu- 5 retor of simplified construction which may be manufactured at materially less cost than those heretofore produced.

A further objec of the invention is to provide a carburetor whe ein a number of parts usually lo formed separately maybe cast integral with each other.

A further object is to provide an improved economizer and acceleration pump.

Furtherobjects and advantages of the invention will be apparent from the following description taken in connection with the appended drawings in which:

Figure 1 is a view in elevation of a carburetor embodying the invention;

Figure 2 is a plan view of the same;

Figure 3 is. a longitudinal section taken on the line 3,-3 of Figure 2;

Figure 4 is a sectional view taken on the line 4-4 of Figure 2;

Figure 5 is a sectional view taken on the line 5-5 of Figure 2;

Figure 6 is a sectional view or the float mechanism taken on the line 6-6 of Figure 2;

Figure 7 is a sectional view of the acceleration Pump taken on the line 1-1 of Figure 2; and

Figure 8 is a sectional view of a modied form of nozzle and Venturi construction.

The carburetor shown in the drawings is of the down draft type (although the invention may be applied to other types) and comprises an upper body section 8 and a lower body section's, the upper section being preferably formed of an aluminum alloy or other suitable metal by die casting, while the lower body section is preferably formed of cast iron and consists essentially of a plain tube having relatively thin walls and separated from the upper section by a gasket I0 of material of low heat conductivity. The upper body section comprises the usual air horn I2 having mounted therein a choke valve I3 carried by a'shaft I4 and having a spring pressed poppet valve I5 mounted therein. An actuating arm I6 is secured to shaft I4 and is adapted to receive a control wire or other member operable from the drivers seat or operable by automatic mechanism such as is disclosed in the application of Hunt and Olson, Serial No. 575,025, tiled November 14, 1931.

The lower section 9 of the carburetor forms a `mixing chamber I8 and has the usual throttle I9 therein mounted on a shaft 20 controlling the iiow of the mixture through the mixing chamber. The lower section 9 is preferably formed of cast iron or other material of low 'heat conductivity to retard the ow of heat from the 5 intake manifold to the float chamber and main nozzle. A float chamber 2| is cast integral with the upper section 8 and houses a oat 22, which is carried by a plvoted lever 24 which controls the inlet valve 26 admitting fuel through the fuel 10 supply duct 21 to the float chamber. The float chamber is provided with a cover 28, which is removably held in place by'screws 30. Thev cover 28 may be formed of stamped sheet metal and is deformed as indicated at'32 to provideclear- 15 ance for the float. The normal fuel level in the carburetor is indicated by broken lines in Figures 3.and 5.

An outer venturi 34 and an inner venturi 36 are provided in the usualrelation and are cast 20 integral with the upper section 8, this operation being made possible by a iin or boss 38 which joins both venturis to the body section 8. 'I'he venturi 36 is provided with a nozzle formed by* a tubular member 45- seated in an inclined bore 25 in the body section 8 and discharging into the air stream axially of the venturi 36. The inclined bore extends downwardly to a point adjacent the bottom of the oat chamber, its lower end being closed by a threaded plug 48. The 30 bore is enlarged at its lower end to receive the plug and to provide a well 50 communicating by way of a port 52 with the oat chamber. The tube 45 is held in place by a meteringl plug 53 threaded in the well 50 and having a metering 35 passage communicating with the bore of tube 45. Tube 45 is cut away as indicated at 54 to provide an air-bleed passage which communicates with the bore of the tube through ports 56. An air bleed duct leads from the upper surface 40 of nn 38 to the passage 54 to provide air bleeding of the main jet through ports 56 after the motor has been in operation long enough to lower the fuel level in the passage below the level of the ports. 45

The tube 45 is cutl away circumferentially as indicated at 62 to provide communication with a vertical idling bore having a tube 64 therein formed at its upper end with a plug 66. The plug communicates with a horizontal bore 68 50 formed in a boss 10 of body section 8, and bore 68 communicates with a downwardly extending idling passage 12 which extends through sections 8 and 9 to a horizontal passage 14 discharging through idling nozzle 16 into the mixing cham- 55 ber I8 posterior to the throttle I9 when the throttle is in closed or nearly closed position. The idling passage 'I2 is ai bled by means of an idle air bleed plug TI, of suitable known contruction, designed to be supplied with air from the air horn and to introduce such air into the fuel owing through passage 12. A port I8 opens from the mixing chamber into passage I2 anterior to the throttle, and with nozzle 'I6 forms a bypass for the throttle when the latter is in its closed position. The discharge from nozzle I6 is controlled by an adjusting screw 19.

The throttle is actuated by a throttle control rod pivoted to a lever 82 which is secured to the throttle shaft 20, the closed position of the throttle being adjustably determined by a stop screw 84 threaded in a boss 86 formed on body section 9. At its opposite end the shaft 20 is provided with a lever 88 connected by a rod to a lost-motion lever formed by two overlapping members 92 and 93, both pivoted 0n a pin 94, their pivotal movement relative to each other being limited by a stop 96 formed o-n member 93. A tension spring 91 extends between projecting lugs on members 92 and 93 and tends to keep them in a position of alinement relative to each other as shown in Figure 5.

Member 93 is connected by means of a rod 98 to the plunger I 00 of an acceleration pump, the cylinder 02 of which is cast integral with the upper body section 8 and communicates with the fioat chamber through a port |03. The plunger |00 is formed with a flexible washer |04 which engages the walls of cylinder |02 in liquid tight relation, being urged thereagainst by a light coiled spring |06 seated in an annular groove formed in the plunger. On the upward stroke oi the plunger |00, fuel is supplied to the cylinder |02 through a passage |0I .which leads to the float chamber 2| and is controlled by a check valve |05 (Figure 7) The lower end or cylinder |02 is connected by a port to an acceleration nozzle II 2 which is arranged to discharge anterior to the throttle I9. An economizer valve controls the flow 0f fuel to nozzle ||2 and consists of a plug |I4 having a bore which is controlled by a valve member IIG which has an upwardly projecting stem designed to be engaged by the plunger |00. A compression spring IIB urges valve member I|6 upwardly with suiiicient force to prevent flow of fuel to nozzle I I2 except when the plunger |00 is forced downwardly, whereupon the uid pressure is exerted on member I I6 through a transverse port ||9 and is sufficient to force it from its seat and permit an accelerating charge of fuel to be discharged into the mixing chamber through nozzle IIZ. It will be seen that, with a slow opening of the throttle, members 92 and 93 will be caused by spring 91 to pivot in unison about pivot 94, causing a slow discharge of fuel through nozzle |I2, plunger |00 being moved downwardly in proportion to the movement of the throttle. If the throttle is opened rapidly, however, the member 93 will move more slowly than member 92 and will thus produce a sustained acceleration discharge, the pressure of the fuel below the plunger being suicient to force valve member I|6 from its seat to permit an acceleration charge to flow through jet I I2. If the throttle is maintained at a substantially full open position, valve member IIS is displaced by contact with plunger |00 and a steady now of fuel by gravity through jet I|2 begins and continues until the throttle is moved away from its full open position. The construction just described thus acts both as an acceleration pump and as an economizer. It will be noted that when it functions as an economizer the discharge is to a great extent independent of the suction existing within the mixture passage, since the static head at nozzle ||2 is suflicient to produce a good flow even when the suction is low, as when the engine is laboring at low speed.

In the modified form shown in Figure 8, a second iin 39 is provided to extend in alinement with fin 38 from the inner venturi 36 to the periphery of the outer venturi 34. The inner venturi 36 is provided at its upper end with a cap 40 which constitutes the main nozzle of the carburetor and which is held in position by means of a peripheral ange 42 which grips the upper end of the venturi. The cap 40 extends downwardly in the venturi and overlies a recess 43 formed therein, cooperating with the recess to form a distributing passageway for fuel discharging into the venturi through a plurality of ports 44. The recess 43 is fed by a tube 51 which is spaced from the walls of an inclined bore 46 to provide an accelerating well and air-bleed passage therearound, and the tube 51 communi'- cates with said well and passage through a plurality of ports 58. In other respects, the construction is the same as that shown in the other figures.

While the invention has been described with particular reference to certain specific embodiments thereof, it will be evident that it is capable of being embodied in other forms and that considerable modification may be made therein within the spirit of the invention as defined in the following claims.

I claim:

1.In a carburetor, a body section having an induction passage formed therein, and a. second body section comprising a portion forming a continuation of said induction passage, a venturi formed integral with said portion and telescoping within said induction passage, a second venturi positioned to discharge into the first named venturi, and a iin connecting the two venturis and formed integral therewith andfprovided with a fuel conduit discharging within the second venturi.

2. In a carburetor, a body section having an induction passage formed therein, and a second body section comprising a portion forming a continuation of said induction passage, a venturi formed integral with said portion and telescoping within said induction passage, a second venturi positioned to discharge into the first named venturi, a fuel reservoir, a. member connecting the two venturis and the fuel reservoir and formed integral therewith and provided with a fuel conduit leading from the fuel reservoir to the second venturi.

3. In a carburetor, a secondary venturi, a downwardly directed primary venturi discharging into the secondary venturi, an integral iin connecting the venturis, and an upwardly inclined nozzle in said fin having a rectilinear bore and terminating in a substantially vertical plane within said primary venturi inwardly of the inner walls thereof.

4.In a carburetor, an air tube, a main venturi and an inner venturi in said air tube, a supporting member connecting the air tube and the venturis, said air tube, venturis, and supporting member being formed integral with each other and being shaped to permit them to be formed by die-casting, said supporting member being provided with a bore terminating at the inner venturi and adapted to receive a fuel nozzle.

5. In a carburetor, a. cast iron body section having an induction passage formed therein, and a die-cast body section comprising a portion forming a continuation of said induction passage, a venturi formed integral with said portion and projecting within said induction passage, a second venturi positioned to discharge into the first-named venturi, a n connecting the two venturis and formed integral therewith, and a removable, inclined fuel nozzle projecting through and discharging within the second venturi.

MILTON E. CHANDLER..

DISCLAIMER 2,042,770.-Mlton E. Chandler, South Bend, Ind. CARBURETOR. Patent dated June 2, 1936. Disclaimer filed September 23, 1937, by the assignee, Bendix Aviation Corporation. Hereby enters 'disclaimer to claim 5 of said' patent.

[O cal Gazette November 2, 1.937.]

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