US1999334A - Carburetor - Google Patents

Description

M. MALLORY priu so, 1935.

CARBURETOR 2 Sheets-Sheet 1 Filed April 28, 1954 n QW; www

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M. MALLORY April 30, 1935.,

GARBURETOR 2 Sheets-Sheet 2 Filed April 28, 1954 ll A s@ Patented pr. 30,I 1935 1.999.334 cAaBUaEToa Marion Mallor Mallory Research Company,

y, Detroit, Mich., assignor to The Toledo, Ohio, a.

corporation of Delaware Application April 28, 1934, Serial No. 722,977

. 10 Claims. This invention relates to a carburetor, provided with a choke valve, and is in the nature of an improvement over the disclosure in my earlier application, Serial No. 702,051, filed December 12, 5 1933. The opening of the choke valve is controlled in part by suction from the intake manifold and in part by the velocity of the air passing through the carburetor.

present form, comprises two oppositel y opening valves with fuel nozzles therein, so that the fuel is always discharged toward the cent the intake passage. air flow and consequently the highest er line of The greatest restriction of velocity is directly across the fuel nozzles. The fuel is therefore atomized as it is drawn through the venturi or throttle. After leaving the nozzles, the atomized fuel does not subsequently strike any wall,

as is the case with other carburetors, but passes directly into the center oi' tively high vacuum, which atomization.

The preferred form or" a region of tends to p comparaerfect the the invention will now be described more in detail in connection with the accompanying drawings, in which Figure i is a vertical section taken centrally of the intake passageway, with the choke valve closed.

Figure 2 is a central vertical section taken at right angles to the the choke valve open.

plane oi Figure l, showing Figure 3 is a plan view of the carburetorv Figure i is a section taken on the line lv-3 of Figure 2.

Figure 5 is a detail view Figure 6 is a plan view of and connections.

of the throttle control. the throttle valves The invention is herein shown as applied to a down draft carburetor having a chamb er i@ with an air inlet it, within which is an annular seat i i for the choke valve lil. to be opened by suction The valve i is adapted from the intatte manifold, to which the lower end of the intatte passageway iti is adapted to be connected.

For this purpose, the chamber t@ is formed with a web i5 from which a hollow stem it extends upwardii! and constitutes a bearing on which the valve i3 is reciprocably mounted. The valve G3i internally with a suction chamber ill a is formed nd alight spring it within the chamber il urges the valve toward its seat i2. A tube I9 connects the chamber il with the intake pasageway M. A cam or eccentric 20 is secured to a spindle 2i extending horizontally across the air intake Il and the 5 spindle 2| is adapted to be rocked by any known means, either manual or automatic, to hold the choke valve i3 positively open or partly open whenever the motor is warm enough to take a leaner mixture.

At one side of the intake passageway it, there is a bowl 22, within which the liquid gasolene is maintained at a substantially constant level by the usual float 23 and needle valve it controlling the inlet to the bowl. l5

The throttle comprises two valves 25 mounted on parallel horizontal spindles 26, which are con nected to each other at one end by intermeshing gear segments 2l, so that they rock in opposite directions in their opening and closing movements. The valves 25 are balanced so that the vacuum on one side does not tend to hold them open. The walls of the intake passageway conn form to the paths described by the outer edges of the valves 25, as shown at 2t, so that all of the fuel which is drawn into the manifold passes beEL tween the valves along the center line oi the passageway. f

As the air is drawn through the chamber it and the passageway it, gasolene is drawn' into the air stream from the bowl 22. For this purpose, each spindle '26 has a depending tubular fuel inlet nozzle or dipper 2t extending below the liquid level in the bowl 22. The fuel passes from the nozzles or dippers 29 longitudinally ofthe respective spindles 26, which are also tubular, and through bores 30 in the valves 25, whence it is discharged into the air stream which passes downwardly through the chamber ill when the throttle is open. 40

One of the valves 25 has a jet orice 3i near its tip and another orifice 32 at its center. The orifice i2 acts as an air bleed to the jet orice 3i when the throttle is opened to a small extent, thus causing more fuel to be discharged, but as the throttle is opened wider, the increased air ow is more directly across the orice i2 and the latter ceases to be an air bleed. If the throttle is opened still wider, fuel is discharged from the orifice 32, as well as from the orice The orif- 50 ces 3i and 32 are so restricted that the mixture will be suciently lean during the rst stages or throttle opening. The other valve 25 has a larger opening i3 at its center which comes into operation only when the throttle is fully open or nearly so, because it is pointed upward and there will be no vacuum created in it until it is turned into the air stream substantially at a right angle thereto. The orifice 43, therefore, plays the role of a power jet.

An idling well 33 is formed in the wall of the passageway I4 and has an outlet 34 and bleed 35.

In the present construction, the throttle valve itself constitutes a venturi. In other words, with the choke valve I3 open, the opening between the valves 25 is the most restricted part of the intake passageway and consequently the air iiow at this point attains its highest velocity. This not only draws gasolene from the bowl but completely atomizes it. The atomized fuel mixture then passes downwardly along the central line of the passageway directly into a region of high vacuum without striking any cold or hard surface, which would tend to condense it again.

In fuel feeding devices, as heretofore used, the volume of the fuel charge is usually controlled by a throttle valve having a single vane which defiects the fuel mixture against the side of the passageway. Thus the fuel, if it has become atomized in the mixing chamber, tends to condense in drops, to be again atomizedat it enters the region of high vacuum in the intake manifold. In the present construction, howev'er, the initial atomization, which is more complete than in the usual carburetor, is retained in full and is further promotedby the projection of the stream directly into the center of the high vacuum in the intake manifold.

It will be noted that in the present construction, as the throttle is opened, the jet orifices are swung downwardly, so that there is an increased iiow of gasolene from the bowl 22 in proper proportion to the increased flow of air. Thus the fuel mixture is regulated by the throttle without the use of metering valves.

When the choke valve I3 is used, if the engine is operating at low speed and is suddenly accelerated, the pressure within the lower end of the passageway I4 will rise, permitting the choke valve to move toward closed position. This maintains a degree of vacuum in the manifold, which will not only suck out more gasolene from the bowl but will at the same time promote its atomization.

I have found, however, that if the spring I8 alone is used in controlling the valve I3 and is made strong enough to choke the engine sulficiently for starting, it will be too stiff when the engine is running normally; that is, when the engine is accelerated and the vacuum decreases, ythe valve will close up too much and over-choke the engine. I have therefore provided a weaker auxiliary spring 44 mounted in a cup 45 at the top of the valve I3. This spring 44 opposes the spring I8, when the cam 20 is moved to partially or wholly open the choke, thus preventing the Valve I3 from over-choking the engine on aceeleration. When the cam 20 is moved to choke the engine, however, the spring 44 is released.

In connection with this carburetor, I prefer to use the throttle control device shown in Figure 5. In this device, the throttle lever 36 is secured to one of the spindles 26 and is connected to a piston 31 which operates in a dash pot 38. In closing the throttle, the manually operated rod 39 engages the lever 36 and a check valve 40 in the end of the dash pot allows the piston to move freely therein, but in moving the rod 39 to open the throttle, it merely releases the lever 36. The throttle is then slowly opened by the air passing therethrough. 'I'his opening will be facilitated if the valves 25 are unbalanced, with the greater area at the inner side of the axis. During this gradual opening movement of the throttle, the piston 31 gradually travels toward the open end of the dash pot, while air bleeds into the dash pot through the bleed hole 42. Thus it is impossible to stall the engine by opening the throttle too suddenly.

From the foregoing description, it will be seen that I have provided a fuel supply device in which the throttle itself constitutes a venturi and the gasolene is fed from the bowl through the throttle directly into the venturi, so that the highest air velocity is directly across the fuel jet nozzles, thereby insuring the best possible atomization. There is no' throttle between the venturi and the intake manifold for the atomized fuel to strike against and to become again condensed, as is the case with the usual carburetors. All of the air, as well as the fuel, is directed by the throttle toward the center line of the passageway and immediately into the region of highest vacuum.

While I have illustrated and described the specific form of the invention which at present seems most desirable, it is apparent that many of the details thereof may be considerably modified without departing from the scope of the appended claims.

I claim:

1. In a carburetor, a fuel passageway, a throttle therein constituting a venturi, and means for discharging fuel in intersecting jets along the center line of said venturi, the angle between the jets being adjustable in synchronism with the adjustment of the throttle opening.

2. In a carburetor, a fuel bowl, an intake passageway, a throttle valve plvotally mounted in said passageway, a fuel jet nozzle in the throttle valve and connected with the bowl and discharging into said passageway at a point higher than the normal level of liquid ln the bowl, the nozzle outlet being on the side of the valve axis which moves downwardly as the valve opens.

3. In a carburetor, a.passageway having a variable venturi, a fuel inlet nozzle opening into the narrowest part of the venturi and means for lowering the fuel inlet nozzle as the capacity of the venturi is increased.

4. The combination with a fuel mixture passageway, of interconnected throttle valves therefor adapted to open said passageway, a lever connected to the axis of one of said valves, a rod movable in one direction to engage the lever and close the valves and movable in the opposite direction to release the lever, the opening movement of the valves being completed by the velocity of the mixture stream passing therethrough.

5. The combination with a fuel mixture passageway, of interconnected throttle valves therefor adapted to open said passageway, a lever connected to the axis of one of said valves, a rod movable in one direction to engage the lever and close the valves and movable in the opposite direction to release the lever, the opening movement of the valves being completed by the velocity of the mixture stream passing between them, and a dash pot, with a bleed, connected to said lever.

6. 'Ihe combination with a fuel mixture passageway, of throttle valves therein adapted to open at the center of the passageway, one of said valves having a fuel duct with small orlilces at 1,999,384 v the inner edge and at the axis of the valve respectively, the other valve' having a fuel duct with a single larger orice located at the axis of the valve.

7. The combination with a fuel mixture passageway having an air inlet formed with an annular valve seat, of a reciprocable choke valve c0- operating with said seat and adapted to be opened by suction through said passageway, a spring opposing the opening of said valve, a second spring, and means for setting said second spring to oppose the rst mentioned spring when a full choke is not desired.

8. The combination with a fuel mixture passageway having an air inlet formed with an annular valve seat, of a reciprocable choke valve cooperating with said seat and adapted to be opened by suction through said passageway, a spring opposing the opening of said valve, a second spring normally idle when full choke is desired, and manually operable means to set said second spring to exert different degrees of opposition to the rst mentioned spring as circumstances require.

9. 'I'he combination with a fuel mixture passageway having an air inlet formed with an annular valve seat, of a reciprocable choke valve cooperating with said seat and adapted to be opened by suction through said passageway, a spring opposing the opening of said valve, a second spring normally idle when full choke is desired, and a manually operable cam directly engageable with said valve to positively open it when choking is not desired.

l0. In a carburetor, an intake passageway having an air inlet, two throttle valve members within the passageway with a variable opening between themand fuel jets discharging in converging lines toward the center of the air stream directly between said valves.

MARION MALLORY.

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