US1858573A - Carburetor - Google Patents

Description

May 17, 1932. L. J. BERKELEY CARBURETOR Filed July 12, 1929 l llnlllfi INVENfOR LAURENCE u. BERKELEY BY i ' ATTOR Y Patented May 17, 1932 LAURENCE J. BERKELEY, 0F CLEVELAND, OHIO CABIBURETOR Application filed July 12,

This invention relates to carburetors such as are employed on motor vehicles for effecting a mixture of air and liquidfuel for use in the internal combustion engine of the 5 motor vehicle.

In the usual carburetor, the conduit through which the air and fuel mixture is supplied by the carburetor to the throttle valve must have a flow area sufficient 'to provide a flow capacity as required for full or maximum load and hence the flow area of the conduit is too large for small loads or when idling. I

The usual carburetor is provided with a Venturi tube which depends upon the flow of air through a relatively small opening at a high velocity and consequently a reduced pressure to effect the flow of liquid fuel into the air current so as to provide the desired mixture of air and fuel.

If the Venturi tube and its air opening be so proportioned as to provide the correct mixture of air and fuel for a certain throttle opening, the law of operation is inherently such that for other throttle openings, the carburetor will not supply air and fuel in the desired proportion to provide the correct mixture. This variation in the mixture at difierent throttle openings has heretofore been compensated for by employing additional fuel jets, dash pot control of the air supply, and the like.

The supply of the air and fuelmixturefrom the carburetor to the engine is usually controlled by a butterfly valve, and the mixture of air and fuel, impinging on the butterfly valve as it flows to the engine, causes the atomized liquid fuel to condense into liquid globules on the surface of the valve, so that a percentage of raw liquid fuel passes to the engine with the well known undesirable rc sults.

To some extent, this condensation of liquid fuel may be compensated for by applying heat, so as to vaporize the fuel, but even then, the heating merely results in providing strata of airand vaporized fuel, which stratified mixture is not in the proper intimate re- 5 lation for complete combustion.

One object of my invention is to provide a 1929. Serial No. 377,733.

carburetor in which the above defects are overcome, by so constructing the carburetor that the final mixture of air and fuel is not obstructed in its flow to the engine, either by a throttle valve or otherwise.

Another object of my invention is to provide a carburetor in which the correct mixture of air and fuel is effected for all speeds and engine loads.

This is accomplished by providing an initial or primary air and fuel mixer of such small dimensions that for any desired slow speed of the engine, there will always be a sufficient flow of air to ensure the low pressure zone, around the fuel necessary nozzle, to

cause the mixer to function on a definite physical law changing.

which is predetermined and un- The final mixture is then made by introducing air into the initial mixture after the initial mixture passes the throttle valve, and in proportion to the speed and the load on the engine.

Other objects and advantages will appear in the following more the invention.

In the accompanying drawings; Figure 1 is detailed description of a central sectional view of a carburetor embodying my invention;

Fig. 2 an elevational view of the carburetor; Fig. 3 a plan view of the movable sleeve member of the carburetor; Fig. 4: a section on the line l-t of Fig. 3; and Fig. 5 a sectionalview of a portion of a carburetor, showing a slight modification of one feature of my invention.

As shown in the drawings, the carburetor may comprise a casing section 1 to which is secured a casing section 2 having a downwardly extending tubular member 3 in which is mounted a fuel'nozzle member 4. The usual adjustable needle valve 5 controls the flow of liquid fuel through the nozzle member 4 and enclosing the member 3 is the usual float chamber 6, which is secured to the easing section 2.

The chamber6 contains the usual float 7 for controlling the operation of the usual fuel inlet valve 8, for maintaining a supply ofliquid fuel in the float chamber, The casing section 1 is provided with an integral tubular portion 9 having at its lower end a Venturi tube section into which the end of the fuel portion 9 is a cone shaped member having a central opening which registers with the conduit 16 of the portion 9. 'Mounted' to move vertically in a cylindrical chamber 17 concentric with the tubular portion 9 is a sleeve 18 having a cylindrical portion 19 which is guided in the chamber 17 and a cylindrical portion 20 of smaller diameter, which is guided in a cylindrical portion 21 of the casing section 22. The cylindrical portions-19 and 20 are connected by a cone shaped portion 23 adapted to seat onthe member 15. Extending laterally from the casing section 1 is an additional air inlet tubular member 24 of relatively large flow area and mounted in said member on trunnions 25 is a butterfly valve 26. A link 27 connects the valve 26 with an operating stem 28, through pivot pins 29- and 30, the stem28 being guided in a bearing hub 31. p

A flexible diaphragm 32 is secured to the stem 28 at ani-ntermediate point and said diaphragm is clamped in placeby a clamping ring 33. Supported by arms 34-, integral with the ring 33 is an interiorly threaded sleeve 35, disposed concentrically of the stem 28. A threaded member 36- is screwed into the sleeve 35 and is provided with a central bore adapted to receive a coil spring 37. The stem 28 extends upwardly through anopening in the member 36 and a. collar 38, at the upper end of the stem, engages the spring 37, so that downward movement of the stem is resisted by the spring.

Carried by the cone shaped member 15 on pins 39 is a cone shaped baifle plate 40 having centralopening concentric with the tubular portioni), the plate being suitably spaced from the member 15,. so as to direct the flow of air to the mixture passing through the tubular portion 9. The cylindrical portions 19 and 20 of the sleeve 18 are provided with grooves41 and 42, whichpermita flow of air from the chamber 43 below the sleeve to the chamber 21 above the sleeve.-

The chamber 44 below diaphragm is connected by a tube 45 with the conduit 46 below the butterfly valve 12, so that the diaphragm 32 is subject on one side to the pressure or suction created in said :conduit.

In operation, when the throttle valve 12 is set for idling or a low engine speed, the mixing mechanismoperates like the ordinary carburetor, and produces a mixture of air and liquid fuel which passes through the conduit 46 and past the valve 12 to the intake manifold of the engine.

The primary mixing mechanism and the flow area of the conduit 46 are so designed as to provide the correct mixture of air and liquid fuel for light loads and engine speeds up to a predetermined slow engine speed.

During the above slow speed operation, the fluid pressures on opposite sides of the sleeve 18 are balanced, the addtional air valve 26 being closed, and the rooves 41 and 42 permitting equalization of pressures on opposite sides of the sleeve. The sleeve 18 is then held seated on the seat member 23 by gravity.

When the throttle valve 12 is opened wider, for an increased demand on theqengine, the fuel supply of the primary mechanism increases out of the correct proportion to the air supply, in accordance with the law governing the flow of air and. fuel.- througdi the mixing mechanism. More air must therefore be added to the mixture to maintain the correct relative proportions of air and fuel.

When the above condition obtains, the improved carburetor is so designed that the suction in conduit 46, which. acts in diaphragm chamber 44, is then sufficient to permit the atmospheric pressure acting above the diaphragnr 32, to overcome the opposing force of the spring 3? and thus cause a downward movement of the diaphragm in proportion to the suction created in the conduit 46.

The downward movement of the diaphragmv 32 causes a proportional opening of the additional air valve 26, the valve being operated through the stem 28 and the link 27. The pressure in chamber 43 below the sleeve member 18 is thus increased by flow of air past the open valve 26 to: chamber 43 and the upper side of the sleeve 18 being subject to the suction in chamber 21, the sleeve 18 will be lifted from the seat member 15,. to an extent such that a balanced condition of prersures on the sleeve is again produced.

. Additional air then flows to the column of air and fuel mixture which issues from the conduit 46, being deflected by the baflle plate 40. The additional air being supplied at an angle to the flow of the primary mixture creates a turbulence, which further breaks up the mixture issuing from the conduit 46.

Some of the additional air flows through the grooves 41 and 42 to the chamber 21 and creates an envelop of airwhich surrounds the reatomized mixture flowing up from the conduit 46 to the chamber 21, and this air envelop prevents the atomized mixture from coming in contact with'the interior walls of the member 22 and the intakemanifold of the engine, so that the fuel in the mixture is prevented fromcondensing on the walls.

The final mixture of air and liquid fuel as produced by the additional air supplied by the unseating of the sleeve 18 is unobstructed in its flow to the engine, since the throttle valve 12 is disposed in the conduit 46, so that there is no valve or obstruction on which the final mixture impinges and which would tend to cause condensation of the fuel.

If there is a further demand on the engine, the throttle valve 12 is opened wider and a greater suction is created in the conduit 46. The diaphragm 32 is thus caused to move further downwardly and open the air valve 26 wider. The increased flow of additional air then causes a greater opening movement of the sleeve 18. The turbulence due to the flow of additional air impinging on the flow of the primary mixture correspondingly increases and at the same time, the air envelop created by the fiow of additional air through the grooves 41 and 42 is maintained.

If the throttle valve 12 be quickly opened, there will be a certain amount of lag or delay before the speed of the engine increases to correspond with the increased opening of the throttle valve. It is desirable to have a richer mixture supplied to the engine during this delay period and in order to permit the temporary supply of rich mixture, I may provide means for delaying the operation of the mechanism which controls the supply of additional air.

I accomplish this result by restricting the communication through which the suction in conduit 46 is transmitted to the diaphragm chamber 44. As shown in Fig. 5, a lug 5O 7 may be provided on the interior wall of the member 24 and tube .45 connects conduit 46 with a bore 51 in the lug. The bore 51 is connected to diaphragm chamber 44 through passage 52, chamber 53, passage 54, and passage 55. Extending intochamber 53 is an adjustable needle valve 56, adapted to be adjusted so as to regulate the rate of flow from passage 52 to chamber 53.

By adjusting the needle valve 56, the creation of suction in diaphragm chamber 44 to equal that in conduit 46 may be delayed for the desired period and this delays the oporation of the diaphragm 32 and the additional air valve 26, so as to permit a temporary flow of rich mixture to the engine, before the additional air controlling mechanism acts.

To adjust the improved carburetor, the throttle valve 12 is turned to its idling position and the needle valve 5 is then adjusted in the usual manner to provide the desired mixture of air and liquid fuel. 'The engine speed is then increased to a certain point by further opening the throttle valve 12 and the pressure of spring 37 is then adjusted by rotating the member 36 until the best final mixture is obtained.

Only onetrial setting is necessary, since the construction is such that if the adjustment be correct for one high speed of the engine, it will provide the correct mixture for all engine speeds and loads.

I have shown one way in which the additional air supply maybe regulated, but it will be evident that the additional air supply may be regulated in various other ways,

within the scope of my invention, such, for example, as by providing a mechanical conneotion between the air valve and the throttle valve.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope 'to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a carburetor, the combination with a primary mechanism for supplying a mixture of air and liquid fuel and a throttle valve for controlling the flow of the mixture through a conduit from said mechanism to the engine, of means for supplying additional air to the primary mixture at a point between the valve and the engine and a battle member for directing the flow of additional air across the flow of the primary mixture.

2. In a carburetor, the combination with a primary mechanismfor supplying a mixture of air and liquid fuel and a throttle valve for controlling the flow of the mixture through a conduit from said mechanism to the engine, of a movable member controlled by the opposing pressures of an additional sup ply of air and the pressure in the flow conduit between the valve and the engine for controlling communication through which additional air is supplied to the primary mixture at a point between the valve and the engine and a bafiie plate for directingthe flow of additional air against the flow of the primary mixture to facilitate the intimate mixing of the additional air with the primary mixture.

3. In a carburetor, the combination with a primary mechanism for effecting a. mix ture of air and liquid fuel, a tubular member through which the primary mixture is supplied, and a throttle valve mounted in said tubular member for controlling the supply of mixture through said member, of an outer tubular section surrounding the outlet of said tubular member and means for supplying additional air to said tubular section to form an air envelop enclosing the flow column of the primary mixture as it flows to the engine.

4. In a carburetor, the combination with a mixing mechanisms for producing a primary mixture of air and liquid fuel and a throttle valve for controlling the supply of said mixture to the engine, of an additional valve for controlling the supply of additional air to said mixture at. a point between the throttle valve and; engine and a movable abutment subject to the suction created between said mechanism and. said throttle valve for controlling the operation of said additional valve. V i

5.. In a carburetor, the combination with a mixing mechanism for producing a primary mixture of air and liquid fuel and'a throttle valve for controlling the supply of said mixture to the engine, of an additional valve for controlling, the supply of additional air to said mixture at a point between the throttle valve and the engine, a flexible diaphragm subject to the suction created between the mixing mechanism and the throttle valve for control-ling the operation of said additional valve, and a spring for opposing movement of said diaphragm by said suction.

6'. In a carburetor, the combination with a mixing mechanism for producing a mixture of air and liquid fuel and a throttle valve for controlling the supply of said mixture to the engine, of a tubular member containing said valve and through which the mixture is sup plied to the engine, an annular valve seat surengine, of atubiilair member through which the mixture is supplied to the engine, ,a-n'annularvalve seat surrounding the outlet of said tubular member, a casin 'section having cylindrical portions. of erent areas. concentrio with said tubular member, a. sleeve member having an annular valve engaging said valve seat, said valve controlling the supply of additional air onlyto said mixture, said sleeve member having cylindrical portions slida-ble in the cylindrical portions of the casing section, and means for controlling the supply of additional air to said sleeve member,

In testimony whereof I have hereunto set my hand this 29th day of June, 1929.

LAURENCE I. BERKELEY.

rounding the outlet of said tubular member.

and. an annular valve member engaging said seat and controlling the flow of additional air to said mixture at a point between the throttle and the engine.

7. In a carburetor, the combination with a mixing mechanism for producing a mixture of air and liquid fuel and a throttle valve for controlling the supply of said mixture to the 7 engine, of a tubular member through which the mixture is supplied to the engine, an annular valve seat surrounding the outlet of said tubular member, an annular valve member engaging said seat and operated by the pres sure of an additional air supply for supplying additional air to said mixture, and means subject to the suction created between the mixing mechanism and the throttle valve for supplying additional airto said valve mem- 8. In a carburetor, the combination with a mixing mechanism for producing a mixture of air and liquid fuel and a throttle valve for controlling the supply of said mixture to the engine, of a tubular member through which the mixture is supplied to the engine, an annular valve seat surrounding the outlet of said tubular member, an annular valve member engaging said seat and operated by the pressure of an additional air supply for supplying additional air to said mixture, and means operated according to the suction created between saidmixing mechanism and said throttle valve for controlling the supply of additional air to said valve member.

9. In a carburetor, the combination with a mixing mechanism for producing a mixture of air and liquid fuel'and a throttle valve for controlling the supply of said mixture to the

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