US2036431A - Carburetor - Google Patents

Description

AWM 79, l% AG. A. MUNcl-l ET Al.

CARBURETOR Filed Mal/wh 14, 1934 2 Sheets-Sheet l Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE CARBURETOR George A. Munch and Joseph W. Boniec, Chicago, Ill.

Our invention relates to carburetors or charge forming devices and has for an object the provision of a device which may be employed in connection with the well-known internal 4combustion engine used in the modern automobile.

A more specic object is the provision of a device which eliminates the use of the ordinary carburetor float and the diiculties in maintenance and operation which the floats ordinarily entail.

A further object is the provision of a device in which the admission of hydro-carbon fuel into the intake manifold may be regulated directly by the operator by positively and controllably increasing or decreasing the size of the fuel intake opening. Preferably our device is so made that the said fuel intake opening and the well-known butterfly valve may be simultaneously opened and likewise simultaneously closed by the operator. By such an arrangement it can be seen that when the motor is being operated at high speed with the butterfly valve approaching a wide open position a larger amount of fuel is admitted for mixture with the air because the size of the fuel intake opening has been enlarged in proportion to the opening of the butterfly valve. Likewise when the motor is being operated at a low speed a smaller amount of fuel is required and as the butterfly valve approaches the closed position the fuel intake opening is simultaneously made smaller. Economy of operation thus results because only the required amount of fuel is supplied for mixture with a given amount of air.

Another object is the provision of a carburetor which will make for smoother operation of the engine and will also enable the engine to accelerate much more rapidly because a proper and sufficient amount of fuel is being supplied by the carburetor at all times.

Another object is the provision of a device in which all openings to the atmosphere will be closed and held in closed position when the operation of the engine ceases. Such an arrangement increases the safety factor of the engine because if an accident should occur and result in overturning the automobile no fuel can escape from the carburetor-while the engine is still operating this danger does not exist and when the operation of the engine stops our carburetor becomes entirely closed and no fuel can escape onto the hot engine or igniting wires. It is of course well known that the carburetors now employed do permit the escape of fuel therefrom in case the automobile is overturnedthis is true regardless of whether the engine continues operation for a short period of time or whether it stops.

Another object of our invention is to provide a carburetor which may be employed as a down draft carburetor or as an up draft carburetor. The elimination of the float aids in accomplishing this object without the employment of highly complicated mechanism.

Another object is the provision of a device of the character described which has few working parts, may be made cheaply, and thus will be efficient and economical in operation.

A further and highly important object is the provision of a carburetor which may be employed with the modern fuel pump and which may take advantage of the fact that the fuel in the fuel line between the fuel pump and the carburetor is under almost constant pressure of the fuel pressure spring. In our device the pressure of the fuel pressure spring is utilized to H cause a spray of fuel into the intake manifold under pressure instead of under vacuum as is the case with the ordinary carburetors now used. It is well known that much difficulty is ployed to effect an even more complete mixture 3 of fuel and air than might be secured without its use. This agitator employs the suction of a carburetor for causing the movement of the working parts.

Other objects will appear hereinafter.

Our invention may be best understood by reference to the accompanying drawings, in which:

Fig. l is an elevational view of our device in position to: be used as a down draft carburetor;

Fig. 2 is an elevational view of the device turned ninety degrees from the position shown in Fig. 1;

Fig. 3 is a top plan view of the device taken from the position shown in Fig. l;

Fig. 4 is a detail view of the agitator which may be employed inl the lower barrel of our device;

Fig. 5 is a longitudinal sectional view taken substantially on the line 5--5 of Fig. 3;

Fig. 6 is a view similar to Fig. 5, except that the carburetor is in a wide open stage of operation;

Fig. 7 is al sectional view taken substantially on the line -'I of Fig. 5;

Fig. 8 is a sectional view taken substantially on the line 3 8 of Fig. 6; and

Fig. 9 is a detail view in section of a breather check valve which may be introduced in the fuel feeding system between the fuel intake line of the carburetor and the outlet of the fuel supplying device or fuel pump.

Referring now to Fig. 5, our device comprises a main barrel IG having an inlet end II and an outlet end I2. A suction operated valve I3 is arranged to close the inlet end II and seats upon a valve seat I4 formed on the under side of an annular collar I5. Collar I5 is attached to the wall of inlet end li by screws E5. The valve 3 is provided with a guide cage I2 which comprises a plurality of longitudinally extending bars I8 which extend from the upper face of valve I3 and are joined to a ring I5 at their upper ends. Centrally of valve I3 is arranged an annular opening 2Q and boss 2I which is arranged concentrically with opening 20. Opening 28 and boss 2! are internally threaded to receive a threaded stem 22. A locknut 23 engages the threads of guide stern 22 and prevents upward movement of valve I3 on stern 22. The lower end 24 of guide stem 22 is unthreaded and extends through an annular guide opening 25 in a transversely arranged guide bar 26. The opposite end of guide stem 22 carries a clevis 27 for a purpose later to be described.

Intermediate the ends of barrel I is arranged an opening 28 through the Wall of said barrel for the admission of a jet 29 and spraying nozzle 30. The `iet tube 3l extends through the opening 28 and is attached to a member later to be described. The open end of spraying nozzle 3E) extends toward the outlet end i2 of the barrel and past the restricted end 32 of a slidably adjustable sleeve 33 having a conical bore 34.

Between the sleeve 33 and the outlet end l2 is arranged a butterfly valve or mixture throttle valve 35. A transversely extending shaft 36 supports butterfly valve and controls the actuation thereof. Exterior bosses 3l and 38 on barrel IG are provided with axially aligned annular bores so as to provide bearings for shaft 36.

Between butterfly valve 35 and the outlet end I2 we preferably arrange an agitator propeller 39 on a longitudinally arranged shaft 45 whose bearings 4I and 42 are substantially in axial alignment with the axis of barrel I2. An agitator supporting cage 43 is of sleeve-like formation and slides into the outlet end I2. A transverse bore 44 threadedly receives bearing 4I and a transverse bore 45 threadedly receives bearing 42. An enlarged opening 45 is arranged in the side wall of cage 43 for the purpose of permitting the insertion and withdrawal of agitator 35i and its shaft 40.

The exterior of outlet end I2 is threaded as at 4l' to engage the internal threads of a removable flange plate 48. The plate 48 may be provided with appropriate bolt openings wherever desired for attachment to the intake manifold.

Exteriorly of barrel III and covering `iet and nozzle opening 28 a fuel controlling inlet member or block 49 is secured to said barrel. This member may be seen in elevation in Figs. I. and 2 and may be secured to barrel I2 by screws. The inner face of block 49 is preferably made concave to t more closely to the convex exterior wall of barrel il). A gasket 5I is preferably arranged on the concave face of block 49.

Referring now to Fig. 8, a fuel inlet nipple 52 is threaded into an annular bore 53 in one of the vertical faces of block 49 and said bore communicates with a longitudinal bore 54. The outer end of nipple 52 may be threaded to receive a threaded connecting collar 55 which, upon being turned into tight engagement with the threads of nipple 52, effects a liquid-tight conduit between the interior of said nipple and fuel pipe 56 whose opposite end is connected to the outlet of any well-known fuel supplying device such as a vacuum tank or fuel pump.

Still referring to Fig. 8, a main fuel supply valve 5I is arranged in bore 54 and is provided with a cage guide 58. A dome valve seat 59 is formed in the upper end of bore 54 and adapted to cooperate in closing bore 54 from communica- -f tion with the restricted bore E0. A coil spring spring El is arranged on the interior of valve cage 58 and adapted to urge valve 5I toward the seat 52. The lower end of spring 5I seats on a disc 52 which is carried by a threaded adjusting screw 63. A plug 64 is threaded into the lower end of bore 54 and is internally threaded for cooperation with the threads of screw 63. A locknut 65 maintains screw 63 in adjusted position. A cap 65 is threaded onto the outer end of plug 64 for the purpose of housing and protecting the exterior end of screw 63. A guide plug 61 is threaded into the upper end of restricted bore 60 and is provided with a cylindrical guide bore for a valve actuating stem 58. A cap 69 is internally threaded to cooperate with the external threads of the outer end of guide plug 68 and with appropriate packing material the cap 69 effects an air-tight connection at the point where valve stem or push rod 68 extends through cap 59. The outer end of stem G5 is provided with a U-shaped bar receiving head 'IG for a purpose later to be described.

A transverse bore 'II communicates between restricted bore 5i] and a longitudinally extending bore I2. The lower end of bore 'I2 communicates with a transversely arranged fuel metering bore 1S which is arranged at ninety degrees to transverse bore 'II.

Referring now to Fig. '7 bore 'I3 extends entirely across block Adjacent its outer end the bore 'I3 is internally threaded to receive the externally and internally threaded sleeve 'I4 and a needle valve stem 'I5is provided with a metering threaded shoulder 'IG whose external threads cooperate with the internal threads of sleeve 'I4 in moving the valve stem 'I5 inwardly and outwardly of bore A packing retaining collar 'I'I is screwed into the outer end of bore 'I3 and retains appropriate packing material in proper position to effect a liquid-tight connection around the outer end of valve stem I5. The inner end of bore 'I3 is internally threaded to receive the externally threaded jet tube 3| heretofore mentioned. Interiorly of jet tube 3! is an enlarged bore 'I3 communicating with a restricted bore I9. Between the two bores just mentioned, however, is a valve seat 25 into which the metering valve needle point ill on the needle valve stem 'I5 is moved by the action of the threaded shoulder TS. The bore 'I9 in the jet tube 3I communicates with a transverse bore 82 which ends in a longitudinal bore 83. The bore S3 supplies fuel into the spraying nozzle 3) heretofore mentioned.

On the outer end of needle valve stem l is keyed a spur gear 84. Reference will now be made to Fig. 2. A rack bar 85 is provided with a row of teeth which mesh with the teeth of spur gear 85% and when the rack bar 85 is moved vertically it causes the rotation of gear 84 and needle valve stem l5 so as to cause the closing or opening of the valve seat 8E) (shown in Fig. 7). An arm 85 is keyed to Abutterfly valve shaft Sit at one end and at its opposite end is provided with a clevice 8l' into which is pivotally arranged the lower end of rack bar t5. A screw lil retains the end of the rack bar in the clevis. Adjacent the untoothed edge of rack bar 85 is arranged a leaf spring support 39 and said support is secured to the face of block i9 by an appropriate screw. The leaf spring Sil is anchored to the support t9 and urges the teeth of rack bar 85 into mesh with the teeth of spur gear 84. An actuating arm 9i is keyed to butterfly valve shaft 35 and provided with an annular opening 92 with which the throttle rod (not shown but is the well-known rod which is actuated by the accelerator pedal of an automobile) may be connected. Adjacent the outer end of boss il@ heretofore mentioned an L- shaped stop member 93 is keyed on shaft t6. In one arm 94 of said member 93 is arranged an idling stop screw 95 which impinges upon a lug 96 arranged on the outside of barrel lll and above boss 38. The opposite member @l of stop member 93 is a stop member which limits the downward movement of arm St and consequently limits the opening of the needle valve by spur gear 84. y

On the outer end of block i9 and adjacent guide plug 6l a lever supporting bracket post 98 is threaded into a threaded bore in said block 49. The free end of post 98 is provided with a clevice @t into which is arranged one end of a lever lili! and said lever is held in place by an appropriate cotter pin. A portion of the lever itl) is arranged between the opposite jaws of clevice lll heretofore mentioned, and when said lever is moved downwardly is adapted to force valve stem 5S downwardly in order to unseat valve 5l. The opposite end of lever lili) is formed into a substantially U-shaped portion lll whose curvature is suicient to cause the outer 'end M2 of said lever to extend substantially vertically. A link i633 carries a cleve ice itt and an appropriate cotter pin retains the end H32 in clevice itil. The opposite end of link |83 is connected to clevice El and re- Ltained therein by an appropriate pin.

Referring now to Fig. 9 a nipple iil having external threads at both ends thereof may be screwed into the bore 53 of block 19. A transverse bore H36 may be arranged in nipple M35 and adapted to communicate at its inner end with the central channel lill. A plug H38 carrying a valve seat H39 and having a Valve and stem lll) may be arranged in said seat before the plug |03 is( screwed into the linternally threaded bore l. The plug itt is also provided with a longitudinally extending valve guide bore, and a coil spring l il is placed on the valve stem exteriorly of the plug m8, and an appropriate cap and locknut M2 may be used to adjust the tension of spring lll and also to retain the spring in operative relation to maintain the valve l l!! in closed position except when the vacuum in channel l'l increases to a suiicient extent to draw the valve Il@ from its seat. An appropriate cap connection H3 may be used to connect the fuel line l l l to the outer threaded end of nipple HB5. The function of valve lill is of course to admit air into the channel l'l so that between successive pulsations of the fuel pump there will be no interference with the proper operation of the carburetor; such interference might be caused in some cases by the creation of a vacuum in the fuel line between the carburetor and the fuel pump during the period of time while the diaphragm of the fuel pump is being drawn downwardly and results in the closing of the outlet valve of the fuel pump. When employing a vacuum tank fuel supplying device for raising fuel from the fuel tank the breather check valve we have described should not be employed. With some types of fuel pumps and some types of engines the breatheii, check valve may be eliminated without any detrimental effect on the operation of the carburetor.

The operation of our device will probably be apparent from the foregoing descriptionl when taken in connection with the drawings but a brief explanation will be given. When the engine is not running the various moving parts of our device assume the position shown in Figs. l and 5 and in this position it can be seen that the air inlet valve i3 is entirely closed. The only outlet to the carburetor for the supply of fuel is through the spraying jet 3l! and since the barrel is closed by the valve i3 there is no possibility of escape of fuel from the carburetor. In this position the spring Si presses against the valve 5l and forces the pin 5t outwardly so as to cause lever li to close the valve i3. Thus the spring presstue of spring El continuously acts against the suction which unseats valve i3 and is constantly in position to close the valve it. The valve i3 would be closed regardless of the fact that a butterfly valve 35 and metering valve 3l were in wide open position when the engine stopped running. When the engine is cranked, either by hand or by mechanical starter, the suction of the intake manifold immediately pulls valve i3 from its seat and allows an incoming supply of air to pass into the carburetor barrel. When this happens the valve 5l is` unseated by the pressure exerted on its top by pin F58 and there is a free passage of fuel from the fuel supplying device which may be a vacuum tank or fuel pump through bores 54, 60, ll, "i2, and l@ to the needle point iii. l'f a fuel pump is being employed any fuel following the course just dened will of course be under pressure of the fuel pressure spring and will 73, 19, 82, and 83 through the spraying jet 3l) and into position to be mixed. with the incoming air. If a vacuum tank is being employed the suction in the carburetor barrel will draw the fuel through the coursesjust defined and it will be mixed with the air upon arriving in the carburetor barrel. As it is desired to speed up the running of the engine the actuating arm 9| is forced in the direction indicated by the arrow in Fig. 2 and simultaneously causes the opening of butterfly valve 35 and needle valve Sl. Thus for an increasing supply of air there is always ready and at hand an increasing supply of fuel and of course when one is decreased the other is also. The idling adjustment of the needle point valve 8l may be effected by raising the rack bar 85 from mesh with the teeth of gear 84 and then turning the gear mentioned in the direction desired. For instance, referring to Fig. 2, turning the gear 84 in a clockwise direcbe forced into bores tion would produce a leaner idling mixture and conversely turning the gear Se in a counter clockwise direction would produce a richer idling mixture. The degree to which the buttery valve and needle valve are held open at idling speed is of course controlled by the idling adjustment screw 95 and this adjustment can be made in the well-known manner.

The agitator propeller 39 is caused to rotate by the suction exerted through the intake manifold and as it rotates it causes an even more complete mixture of the air and fuel. It might be thought that when our device is employed as a down draft carburetor there would be an escape of fuel into the carburetor barrel when the engine has stopped. This is not the case, however, because the closing of valve I3 by the spring pressure of spring 6l simultaneously closes valve l and the supply of fuel trapped between the valve 5l and the outlet in spraying jet 3E! has no vent opening through which to receive any air so as to permit the fuel to run out of the spraying jet. It would thus be necessary for this trapped fuel to create a vacuum somewhere between jet 30 and valve 51 in order to escape; since a vacuum cannot be thus created by trapped fuel it will not leak from jet 3D as long as valve 5l is closed. As before stated, it may be desirable with some types of engines having some types of fuel pumps to introduce a breather check valve between the fuel pump and the carburetor in order to permit smoother operation of the engine during the time when the diaphragm of the pump is being moved in the direction to draw fuel from the fuel tank into the fuel chamber of the fuel pump. Valve HD is designed for this purpose and its construction and operation have been heretofore described.

While we have shown and described our preferred form of construction we do not wish to be limited to the details herein shown but wish to avail ourselves of all modifications coming within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A carburetor comprising a mixing barrel, a main fuel supply valve, a metering valve for Variably controlling the supply of fuel, a mixture throttle valve for variably controlling the supply of mixture, an operative connection between said metering valve and said mixture throttle valve, means operable by the suction of the motor to which the carburetor is connected for opening said main fuel supply valve when said motor is in operation, a fuel supply pipe leading to said main fuel supply valve, a breather check valve for admitting air to said main supply pipe, and a suction operated agitator arranged in said mixing barrel and adapted to mix incoming fuel and air.

2. A carburetor comprising a mixing barrel, a main fuel supply valve, a metering valve for variably controlling the supply of fuel, said metering valve having a threaded stem and a gear member mounted upon stem whereby rotation of said gear serves to variably regulate the admission of fuel, a mixture throttle valve for variably controlling the supply of mixture, a rack in operative relation with said gear, an operative connection between said rack and said mixture throttle valve, and a suction operated valve connected to said main fuel supply valve for opening said main fuel supply valve when said suction operated valve is opened.

3. A carburetor comprising a mixing barrel, a main fuel supply valve, a metering valve for variably controlling the supply of fuel, said metering valve having a threaded stem and a gear member mounted upon said stem whereby rotation of said gear serves to variably regulate the admission of fuel, a mixture throttle valve for variably controlling the supply of mixture, a rack in operative relation with said gear, an operative connection between said rack and said mixture throttle valve, a suction operated valve connected to said main fuel supply valve for operating in unison, a fuel supply pipe leading to said main fuel supply valve, and a breather check valve for admitting air to said fuel supply pipe.

4. A carburetor comprising a mixing barrel, a main fuel supply valve, a metering valve for variably controlling the supply fuel for admission to said mixing barrel, said metering valve having a threaded stem and a gear member mounted upon said stem whereby rotation of said gear serves variably to regulate the admission of fuel to said mixing barrel, a mixture throttle valve for variably controlling the passage of mixture through said mixing barrel, a rack in operative relation to said gear, an operative connection between said rack and said mixture throttle valve so arranged that the opening of said mixture throttle valve will cause variable opening of said metering valve, and a suction operated agitator arranged in said mixing barrel and adapted to receive fuel and air together before the same are withdrawn from said mixing barrel.

GEORGE A. MUNCH. JOSEPH W. BONIEC.

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