US2422751A - Carburetor - Google Patents

Description

June 24,A 1947.y E. R. SCHNEIDER CARBURETOR Original Filed May 20, 1943 3 Sheets-Sheet l liar/uy CARBURETOR Original Filed May 20, 1943 3 Sheets-Sheet 2l June 24, 1947. ,v `lE1, R, SCHNEIDER 2,422,751

- clmunmon origi'l Filed nay 2o, 1945 s sheets-sheet s IIIIIIIII mmm;

III). A

- turi can, for any given volume gear.

Patented June 24,1941

CABBURETOR Edgar R. Schneider, St. Louis, Mo., alsignor of one-tenth to said Schneider, al trustee for 01a! H. Anderson, Sait Lake City, Utah continuation or application serial No. ss'moi, 2.

V`1llay 20, 1943.

1944, Serial N0. 518,204

This invention relates to improvements in compensating carburetors. More particularly, this invention relates to improvements in carburetors wherein the volume of air and fuel varies to compensate for variations in the load on the engine connected to the carburetor.

It is therefore an object of the present invention to provide an improved carburetor wherein the volume of air and fuel is variable.

This-invention is a continuation of the invention disclosed in my co-pending application Serial No. 487,701 entitled Multiple Venturi carburetor which was filed May 20, 1943. l v The running system of a carburetor usually consists of a Venturi tube in which a jet is positioned. This jet is positioned adjacent the section of the Venturi tube that has the smallest internal diameter, and it will emit fuel when the velocity of the air passing through the vvenvelocity of air passing through the venturi depends on the internal diameter of the Venturi tube, as well as the volume of air required by the engine, the velocity of air passing through a venof air, be increased by decreasing the diameter of the venturi. Such an increase in the velocity of air, for any given volume of air required by the engine, would cause the running system to begin to operate atmuch lower engine speeds than is now possible. For example, modern running systems may not begin to operate until the engine attains a speed corresponding to 20 or 25 miles per hour in high By reducing the diameter of the venturi, it is possible to have that running system begin to operate at a speed corresponding to 9 or 10 6 Claims. (Cl. 261-41) turi reaches a predeterminedv value. Since the m and the secondary throttle valve is open. The

miles per hour in high gear. Having the running system come into operation at such low engine speeds. is highly desirable since running systems invariably are much more eiilcient than are idling systems. Such an arrangement, therefore, permits the engine to run at a higher eiliciency for a greater percentage of the'running time, and thereby achieves a greater overall emciency. It is therefore an object of the present invention to provide a carburetor wherein the running system beginsto operate at low engine speeds.

The needsvof an engine are quite variable and they must be fully met or the engine will not give its maximum eilicieney. The best and most accurate index of the' needs of an engine are the pressures at the intake manifold of the engine.

The present invention makes use of these pres- 55 erence indicate like parts throughout the several sures to vary the volume of air and fuel provided 45 begin to operate at low engine speeds, but

50 tion vto provide a carburetor wherein the fuel is This application January l.

by the carburetor and thereby achieves the proper amount of air and fuel for each load condition..

Itis therefore an object of the present invention to provide a carburetor which provides the Proper amount of fuel and air for any given load or Y speed, and varies the volume of fuel and air commensurate with the pressures at the intake manifold of the engine.

The present 4invention is enabled to have its running system begin to operate at low speeds, to change the volume of fuel and air commensurate with the pressures at the intake of the engine and to provide for adequate air volume at all speeds by using at least two'Venturi tubes in addition to the idling system. One of these Venturi tubes is closable only by a master throttle valve, while the other is closable by the master throttle valve and a secondary throttle valve. The venturi that is closable only by the master throttle valve will provide a fuel and air mixture whenever the running system is operating, while the other venturi will provide a fuel and air mixture whenever the running system is loperating volumes of mixture provided by the two Venturi tubes will preferably be such that they can unite to give a combined volume of fuel and air that will provide the necessary power for acceleration periods. In this way, the invention can provide I0 one range of fuel-air volumes for constant velocity and even-load conditions and can supply another range of fuel-air volumes whenever a yheavy load is placed on the engine or the speed is to be increased. It is therefore an object of the present invention to provide an improved carburetor having a venturi that is closable only by a master throttle valve and a second venturi that is closable a secondary throttle. A

The use of a small, normally open primary venturi that is closable by a master throttlevalve is further desirable because it affords a high velocity of air through the open venturi. This hish velocity not only causes .the running system to it also provides better atomization of the fuel. Such high atomization is quite useful because it increases the economy and emciency of It is therefore an object of the present invenhighly atomized.

These and many other objects I accomplish with the device illustrated in the accompanying drawings in which similar numerals and letters of refby a master throttle valve and" the engine.

' views. In the drawing and vaccompanying description, .la preferred form of the invention is shown and described but it is to be understood that the` drawing and accompanying description do not limit the invention and the invention is defined by the appended claims.

In the drawings in which I have shown my invention,

Figure 1 is a vertical section of the carburetor; and that section is taken along the center line of the carburetor, but the section of the partition between the two mixture passages is taken along a line spaced behind the centerline.

Figure 2 is a side elevational view of the carburetor taken ninety degrees from that shown in Figure l, and it shows the positioning of the vacuum control diaphragm.

Figure 3 is a section on line 3--3 of Figure 1.

Figure d is a vertical section through the carburetor of Figure 2.

In the drawings I have shown .the carburetor as made of a Venturi casing A, having thelower end 5 provided with a securing iiange by which it may be snecured to the intake manifold of the engine.' The Venturi casing A starts as a cylindrical chamber in which a master throttle valve 'i is ypivotally mounted and an idling jet Bil is provided. This jet can best be seen in Fig. 4 where it is shown in proximity to the master throttle valve l. Feeding this jet is a duct iii that supplies gasoline from vthe source of fuel. Adjacent jet 39 is the idle air screw d2 that is standard equipment on present-day carburetors. The chamber S then merges into an outwardly dared chamber 8 which then merges into dual Venturi `tubes formed by av dividing partition 9 that divides the chamber into air ducts a and b. A dual Venturi casting it is set in the top end of the 'casing A, which casting carries depending spaced Venturi tubes il and i2 that are adapted to be set into the dual Venturi casting iii of the casing A to form the perfectly bored and fabricated Venturi tubes for drawing the fuel from the jets into the air stream. Venturi tube il is larger in diameter than is tube I2, and the sum of the areas oi the tubes H and I2 is equal to or greater than the area of the single or multiple venturis used in present-'lay carburetors. Such an arrangement is desirable to provide an adequate iiow of air and fuel to the engine at all positions of the master throttle valve.

Each of these Venturi tubes are identical in form and they are divided by'a central partition. Within the Venturi tubes there are smaller Venturi tubes i3 and it spaced axially therein combined mixture to the desired degree.

Above these Venturi tubes and their housing, there is a. constructed air inlet connection I9 which is provided with the usual butterfly choke valve and onto the top end 0f the connection the air cleaner is usually mounted. Within the larger of the air ducts a I provide a butterfly control valve 2li mounted on the rod 2| which extends through the outside wall toa control plate 22. The inner end of the rod 2i is mounted in the partition 9 to give it rigidv support. The outer end of the rod 2| is also provided with an adjustable stop to insure against suction locking of the butteriiy in high vacuum conditions. A crank pin 23 extends from the plate 22 and a link Zt is carried on the pin 23 with the free end thereof attached to. and controlled by a ilexible diaphragm 32 carried in the diaphragm casing 25. A spring 34 biases the valve 20 to open position, but the valve will move to closed position during conditions of sub-atmosphericpressure in the cylindrical chamber The spring 3d is positioned in the horizontally disposed cylinder 33 extending to the left of the diaphragm casing in Fig. 2 of the drawing. One end of the spring 35i bears against the exible diaphragm and the other bears against the end ofthe adjusting screw 35 threaded in the screw-retaining cylinder. Adjustment of this screw is usefui in determining the pressures to which the valve 2li will be responsive. A line 2S from one side of the cylindrical chamber below the throttle valve leads to the closed side oi the vacuum control so that the suction or vacuum of the motor is utilized 'to control the butterfly valve 2E and the valve is therefore controlled commensurate with the pressure at the intake manifold not shown, that supplies the fuel for the carpresent-day carburetors. 'Volume of the mixture aiorded by the venturi i4 is adequate to operate the engine at constant velocity under light loads, 4and will give exceptionally economical performance. During periods of acceleratiomthe venof the engine.

When the engine is at rest, the master throttle valve l will be closed, and the throttle valve 2G will be open. The master throttle Valve 'l is the usual type of pedal operated throttle valve now used in most present-day carburetors and is spring biased toward closed position. The throttle valve 20 on the other hand is biased to open position by the spring 3B that is positioned and held in the horizontally disposed cylinder 33 shown in Fig. 2.

When the engine is started, the master throttle valve 'l may `still remain in closed position, but the throttle valve 2t will be moved to closed position. This closing of the valve 20 is eiected by the nexing of the pressure responsive diaphragm 32, which iiexing will cause a movement of link 26 and a consequent vrotation of plate 22 and valve 2li, The iiexing of the diaphragm 32 is the result of aldifference between the pressures on the opposed surfaces of the diaphragm. Atmospheric pressure will be exerted on one side of the diaphragm and a sub-atmospheric pressure will be exerted on one side of the diaphragm.

The sub-atmospheric pressure on the one side of' the diaphragm is obtained by placing that one side of the diaphragm in communication with the atmosphere in the portion of cylindrical chamber 6 which is adjacent the intake manifold of the engine. ',I'hisvis done by use of the conduit 26.

When the engine is idling, the pressure in the intake manifold will be considerably below atmospheric pressure and will easily overcome the'force exerted by the spring and will thereby close the valve 20. While the valve 2|) is closed, the venturi I3 will -be closed and the venturi lwill have to provide the air necessary to draw tion in force on the spring will permit the valve to open up somewhat. The valve 20 will remain open until the pressure in the intake manifold again decreases, as it will when the engine reaches a near-constant velocity. The valve 20 will again open if the throttle valve 1 is opened further, because such further opening will again increase the pressures in the intake manifold.

This arrangement is highly desirable because it opens the valve 20 and thereby increases the volume of the mixture whenever the master throttle valve I is opened further. ing of the volume of the'mixture is highly desirable because the further opening of the masterthrottle l usually occurs when the engine is to accelerate. From this it is apparent that the engine will run on the volume of mixture from venturi I4 Whenever the engine is running at constant or near-constant velocityand will be given an additional volume of mixture whenever it needs it, as it will during periods of increased load and acceleration.

In the event that it is deemed advisable to cast the casing A with the Venturi tubes as integral parts thereof rather than as inserts as shown in the drawings, applicant feels that this should be considered merely a structural detail and not of patentable moment. It will also be possible to cast a cylindrical body in the casing A and use a piston therein rather than using the plate type diaphragn shown in the other views ofthe drawings. Mention is being made of these variations and possible changes to show that such modifications have been made and are possible but are considered to be within the spirit of this invention and the scope of the appended claims.

What I claim is:

1. In a carburetor of the character described, a casing providing a single fuel mixture outlet at one end and a single air inlet at the opposite end, said mixture outlet being adapted for connection to an intake passage of an internal combustion engine, a manually operable throttle valve in said outlet, a primary mixture passage in the casing intermediate said inlet and said outlet, an auxiliary mixture passage in the casing in parallel with the first said mixture passage, a Venturi tube in each of said passages, a fuel jet operatively associated with each of said Venture tubes, a control valve in the downstream end of said auxiliary mixture passage, means normally tending to open said control valve, and a movable wall subjected on one side thereof to the pressure downstream of said manually operable throttle valve to close said control valve by predetermined engine suction.

2. In a carburetor of the character described. a casing providing a single fuel mixture outlet ai; one end and a single air inlet at the opposite end, said mixture outlet end being adapted for connection to an intake passage of an internal combustion engine, a manually operable throttle valve in said outlet, generally parallel primary and auxiliary mixture passages in said casing intermediate said inlet and outlet, a Venturi tube in each of said passages, afucl jet operatively associated with each of said Venturi tubes, ya

control valve in the discharge end ofV said auxilary mixture passage, means normally tending to open said control valve, and a. .pneumatic motor communicating with said mixture outlet by a conduit that opens directly into said mixture outlet downstream of said manually operable throttle valve to close said control valve by predetermined engine suction.

3. In a carburetor o! the character described, a casing providing a fuel mixture outlet and an air inlet, said mixture outlet being adapted for connection to an intake passage of an internal combustion engine, a manually operable throttle valve in said mixture outlet, a primary and an auxiliary mixture passage in parallel relation in said casing, said mixture passages communicating said 'air inlet with said mixture outlet. a Venturi tube in each of said mixture passages, a control valve in said auxiliary mixture passage, a spring-loaded pressure-responsive diaphragm operatively connected to said control valve, and conduit means between one side of said `diaphragm and apoint in said mixture outlet downstream of said manually operable throttle valve.A

said spring-loaded pressure-responsive diaphragm biasing said control valve to open position and being operable by predetermined engine suction to close said control valve.

4. In a carburetor of the character described,- a casing providing a fuel mixture outlet and an air inlet, said outlet being adapted for connection to an intake passage of an internal combustion engine, e, manually operable throttle valve in said mixture outlet, primary and auxiliary mixture passages in .parallel relation in said casing, each of vsaid passages being in communication with said air inlet and said mixture outlet, a Venturi tube in each of said passages, a fuel jet operatively associated with each' of said Venturi tubes, a control valve in said auxiliary mixture passage. la housing secured to said casing, a pressure-responsive diaphragm in said housing and operatively connected to said control valve, a conduit between said housing and said casing that places one side of said pressure-responsive diaphragm in direct communication with said mixture outlet downstream of said manually operable throttle valve,and resilient means to bias said pressure-responsive diaphragm to valve-opening position, said resilient means and said diaphragml normally tending to maintain said control valve in open position but being operable by predetermined engine suction to close said control valve.

5. In a carburetor of the character described, a casing providing a fuel mixture outlet and an air inlet, said outlet being adapted for connection to an intake passage of an internal combustion engine, a manually operable throttle valve in said mixture outlet, primary and auxiliary mixture passages in parallel relation in said casing, each of said passages being in communication with said air inlet and said mixture outlet, a Venturi tube in each of said mixture passages, a fuel jet operatively associated with' each of said Venturi tubes, e, control valve in said auxiliary mixture passage, a movable wall operatively connected to said control valve, adjustable spring means operative to bias said movable wall into valve-opening position, and conduit means connected to said mixture outlet to place one side of said movable wall in direct communication with said mixture outlet downstream of said manually operable valve to overcome said bias and close said control valve by predetermined engine suction.

ing that is adapted for connection to an intake .passage of an internal combustion engine, a manually operable throttle Valve that is in said mixture outlet and is operable to control the flow of air-fuel mixtures through said mixture outlet, primary and auxiliary mixture passages that are spaced apart and are spaced from said mixture outlet, a Venturi tube in each of said mixture passages, a fuel `iet operatively associated with each of said Venturi tubes, the fuel jet and Venturi tube in said primary mixture passage being adapted to provide an; air and fuel mixture that can pass to the said mixture outlet of said casing, said fuel jet and Venturi tube of said auxiliary mixture passage being adapted to provide an air and fuel mixture that also can pass to the said mixture outlet of said casing, a control valve in said auxiliary mixture passage that is openable to .permit the air and fuel mixture of said auxiliary mixture passage to pass to the said mixture outlet or said casing and is closable to keeplthe air and fuel mixture of said auxiliary mixture passage from passing to the said mixture outlet of said casing, means normally tending to open said control valve, and a movable Wall subjected on one side to the pressure in said mixture outlet downstream of said manually operable throttle valve to close said control valve by predetermined engine suction, whereby the flow of air and fuel :from said primary mixture passage through the said mixture outlet of said casing is manually controlled while the ow of air and fuel from said auxiliary mixture passage through the said mixture outlet of said casing is pressure controlled as well as manually controlled.

EDGAR R. SCHNEIDER.

REFERENCES errno 'The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,614,973 Sherrick Jan. 18, 1927 1,826,202 Cole Oct. 6, 1931 2,269,930 I Ericson et ai Jan. 13, 1942 1,113,551 Greuter Oct. 13,1914 2,193,533 Kishlirie et al Mar. 12, 194,0 2,208,702 Read July 23, 1940 1,Q09,389 Ballet al May 16, 1933

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