US1915852A - Carburetor - Google Patents

Description

June 27, 1933'. G. R. mcisdu 1,915,852

GARBURETOR Filed April 24. 1930 Pie, 4

INVENTOR GEORGE R. ERICSON ATTORNEY A 1 body casting having Patented June 27, 1933 GEORGE R. ERICSON, OF ST. LOUIS,

CORPORATION,

OF ST. LOUIS, MISSOURI, A

MISSOURI, ASSIGNORYTO CARTER CAR BURETOR CORPORATION OF DELAWARE CABBURETOR Application filed April 24, 1930. Serial No. 446,899.

This invention relates to carburetors and more particularly to thermostatic controlling I devices for carburetors. This application is a continuation in part of my application #358,700 filed April 27th, 1929 which has resulted in Patent #1,872,708 granted Au-v gust 23rd, 1932. It is an object of the invention to provide a simple andeasily manufactured thermostatic controlling device for varying the mixture ratio of fuel and air with the temperature. I

It is a further object of. the invention to produce a device of the above described character which will remain constant over a long period of operation. v

It is a further object of this invention to provide a thermostatic controlling device of the above described character in-which the thermally. operated element is heat treated to eliminate strains in the metal and to provide a thermal element of such construction-- to permit the heat treatwithout distortion forcibly brought The and arrangement as ment of the element caused. by the ends being together during the heat treatment.

invention will be better understood upon ref-- erence to the accompanying drawing in which corresponding reference numerals represent corresponding parts throughout.

Referring to the drawing:

Figure 1 shows a vertical, sectional view of a carburetor embodying this invention,

' Figure 2 shows an end view of a thermostatic control element of a carburetor according to this invention.

Figure 3 shows a longitudinal sectional view of the parts shown in Figure 2.

Figure 4 shows an end view of the device shown in Figures 2 and 3 taken from the end op osite to that shown in Figure 2.

The reference numeral 1 indicates a main 'an air horn or air inlet 2 therein. This air horn leads into an air chamber 3 which discharges through a venturi 4 formed in a second body member extending from the which is attached to the first body member by suitable screws 6. The body member 5 is provided with a flange 7 by means of which it is attached to the inlet manifold. of an internal combustion engine in the usual manner.

A throttle valve 8 mounted on a suitable shaft 9 is provided for controlling the outlet of the carburetor. The body member 1 is provided with a downward extension 10 surrounded by an annularseat 11, a cup-shaped bowl 12 is seated at its rim on the annular seat 11 and retained in position by a nut 13 which is threaded into the lower end of the extension 10.

Fuel is supplied to the bowl by any suitable means, such as an engine driven pump or a vacuum tank, and it is maintained in the bowl at substantially thelevel A-A by a conventional float mechanism 14:. The inlet connection and the float valve are not shown, these being so well known in the art that no further description is necessary.

A standpipe 15 is threaded into the lower portion of the air chamber as shown. Ports 16 are provided in the lower portion of the standpipe to receive air from the air chamber 3. A restricted throat 17 is formed in the standpipe above the entrance of the air inlet'for the purpose ofincreasing the air speed at that point porization of the fuel. An air bleed 18 is drilled in the lower portion of the standpipe and communicates with the well 19 formed in the extension 10 of thebody member 1. The well 19 is provided with screw threads 20 at its lower-portion to receive the corre sponding threads of the nut 13 and also to receive the threads of a nozzle 21 which is mounted concentrically with the well 19 lower portion of this well to the restricted portion 17 of the standpipe.

Accelerating holes 22 are provided for the nozzle and form a communication between the well 19 andthe interior of the nozzle. Fuel is supplied to the well 19 and to the interior of the nozzle through suitable passages 22 and 23, respectively, communication between the well and nozzle to insure thorough r. I

which form i responding to Excellent vaporization of the gasoline is acsired to and the space between the nozzle and the end of the nut 13, as indicated at 24.

A cross connection 25 supplies fuel to the lower end of the idling tube 26 and the fuel enters this tube through the small port 27, as shown. Conventional air bleeds 28 are provided in the idle tube above the fuel level, and the upper end of the tube is connected to a bore 28 in the body member 5. From this bore the fuel passes to an outlet port 29 in the side of the outlet passageway 30 of the carburetor. This port is formed at the the point where the throttle valve closes against the side of the passageway and when the/throttle is slightly open, as it is when adjusted for proper idling, at least a portion ofthe port 29 is in communication with the mixing conduit at a point posterior to the throttle. In this manner a suction connection from a point posterior to the throttle is provided for admitting the idling fuel and for affecting the valve 42. When the engine is operating under its own power but at low speeds, for instance, with the throttle one-' eighth open, the port 29 would be fully exposed to the suction above the throttle and that suction will be very high,

perhaps cor- 7 or 8pounds per square inch.

cordingly obtained, and it is therefore desirable to lean out the mixture to a certain extent. The suction connection comprising port 29, passages 28, 33, and 36 transmit the suction from above the throttle to the valve 42 causing it to close or partly close, and thereby lean out the mixture.

body member 32 is threaded Jet nozzle 32 comprises a large passageway 33 calibrated to meterthe maximum quantity of fuel which it is depass through the carburetor under low temperature conditions threaded bore 34 which receives the screw threaded ends of a second body member 35 having a longitudinal bore 36 of comparatlvely large diameter so that it does not form a restriction or calibration, brated longitudinal bore 37 of considerably smaller diameter than the bore 36, a transverse bore 38 of larger diameter than the bore 37 is drilled in the body member 35 and pro vides the main communication between the bore 36 and the fuel in the bowl.

A bracket 39 having a perforation 40 is attached to the two bodymembers by screwing them together, the perforation 4O surrounding the threaded end of the body member 35. The bracket is bent into a U shape at the end opposite the perforation 40 to provide a parallel short leg 41 to which may be attached the thermallyoperated controlling member 42. This control member is formed of a straight flat piece of the usual bi-metallic fuel is then metered at and a small cali-' thermostatic material, the more expansible also be readily engaged by a wrench.

he passageway 38 is so calibrated that when the temperature 1 is reasonably high, say, above degrees Fahrenheit, in the fuel bowl of the carburetor, the combined resistance offered by the passageways 22, 23, and 38 regulate the flow of fuel to give a proper mixture for operating under high temperature conditions. It will be understood that the control member42 moves to the left of the Figure 3 and closes when the temperature is in excess of approximately 70 degrees Fahrenheit, thereby closing the opening 37 and causing all the fuel for the carburetor to flow through the passageway 38. When the temperature falls below '70 degrees Fahrenheit in the fuel bowl, the member 42 moves to the right, openin the passageway 37, thereby enriching the uel mixture by t e capacity of the passage 37 which is approximately one-eighth of that of the passage 38. The the passage 33 and at the passages 22 and 23.

feature of this invention is that the thermostatic metal is made comparatively short, but very thin, and flexible by mechanical force as well as by changes in temperature, and this has a very important object in this invention, in addition to securing the great cheapness and sim licity of construction which are also obtainable with this dev1ce.

In cold weather, when the automobile to which the carburetor is attached, is operated continuously at low speed, the fuel in the carburetor bowl will reach a temperature of ap proximately 7 0 degrees or more without very great delay; for instance, when the outside temperature is zero, the carburetor bowl will probably attain a temperature of 70 degrees within about three to five miles, but if the car is driven at high speed, for instance, in excess of 40 miles an hour, the rate of fuel flowinginto the bowl is so rapid that the temperature existing in the bowl is likely to approach that existing in the fuel tank and not that of the engine. The fuel tank is ordinarily mounted at the rear end of the car and is very likely to be cold, and the rate of heat conduction down through the body of the carburetorbeing substantially constant, a rapid lowering of the temperature in the bowl is experienced, with the result that one would expect the thermostat to open up and give an undesirably rich mixture while drivspeeds of miles an ing the car at high speed in cold weather. This difliculty is overcome in my device by. the following construction:

The thermally controlled element 42 is made very thin, say, in the order of .017 of an inch in total thickness of the two metals, and the length and width are so selected with respect to thesuction of the carburetor that the suction at the end of the bore 37 at speeds above 40 miles an hour will bend the member 42 into contact with the face of the member 35, closing the bore 37. By reason of the fact that at speeds of 40 miles an hour or more, the fuel is thoroughly vaporized by the comparatively high air speed, it is entirely unnecessary at high speeds to supply additional fuel even. if the temperature is low. This condition is also partly due to the fact that the temperature in the bowl at hour or more is likely tolpe much lower than that of the engine itse A choke cone 44 is slidably mounted on the standpipe 15 and is operable by a yoke 45 mounted on an arm 46 for the purpose of restricting or cutting off the annular passage 47 between the upper end of the standpipe 1'5 and the throat of the venturi 4. This arrangement is used for starting or for extreme cold weather conditions, as desired.

The operation of the device is as follows:

The carburetor being attached by means of flange 7 to an internal combustion engine, air enters the air inlet 2 and flows through port 16 in the base of the standpipe up past the nozzle and through the restriction 17 in the standpipe and into the main venturi or mixing chamber 4. Air from the inlet 2 also passes through the air chamber 3 and flows through the annular space 47 around the top of the standpipe. Fuel being supplied to the bowl and maintained at a constant level Av-A, the suction caused by the operation of the engine draws fuel into the passageway 38 through the bores 36, 33, 22, and 23 into the nozzle and the accelerating well 19.

Air from the air chamber flows down through the. air bleed 18 and mixes with the fuel in the nozzle and the accelerating well, passing up through the discharge outlet of the nozzle into the primary mixing chamber 48 above the restriction 17 in the standpipe. When the carburetor is operated under high temperature conditions, for instance, above degrees Fahrenheit, the thermally controlled element 42 will be bent to the left to close the end of the passageway 37 so that all the fuel must pass through the passageway 38, thereby providing a mixture which is calibrated for high temperature operation. When the temperature is low, as when starting up on a cold morning, the' thermally controlled element 42 is bent to the right as shown in Figures 1 and 3 to permit additional fuelto enter the passageway and'to ing enrich the mixture thereby in the degree of approximatel 12 percent. When the choke valve' 44 is c osed and the throttle slightly opened, as for starting at low temperature, the suction is built up at higher than normal for the same operating speed by the fact that the choke valve ,is closed preventing the relief of the suction by air entering at 47. When the engine iscranked at normal cranking speeds, say, from 40 to 100 R. P. M., the suction developed at such low speeds is not sufficient to close the valve 42 if the temperature is extremely low-for instance, zero Fahrenheit or below. However, when the enginestarts to run under its own power, the suction is substantially built up due to the increase in operating speed of the engine to anywhere from 200 to 400 R. P. M. The

high suction which will now be built up by.

the engine is communicated to the valve 42 which closes and leans out the mixture, and in this manner a member is provided for leanout the mixture as soon as the engine starts to run under its own power. When the valve 44 is opened, the suction H again decreased, and if the temperature is low and the speed not above normal, the valve 42 will again be open in response to the lowered suction. It will be noted that the port 29'is posterior to the throttle valve when that valve is slightly open and the port is also posterior to the choke valve 44, so that the suction eonveyed to the valve 42 may be responsive to movements of either the throttle or choke valve, and the claims should be construed ac cordingly. When the engine reaches normal operating temperature, heat from the engine is conducted down through the-body to the carburetor and the extension 10 to the fuel in the bowl, thereby warming the fuel in the bowl and the thermally controlled element 42 which thereupon bends to the left and closes the end of the orifice 37.

When the fuel in the main fuel tank is very cold and the car is operated at high speed, the temperature in the bowl will again fall, due to the rapid rate of flow of the cold fuel into the bowl. This, however, will not cause the thermally controlled element 42 to open the end of the passageway 37, except under extreme cold conditions, because the suction will hold the member 42 in closed position.

I claim: a

1. In a carburetor, a fuel supply device for forming a combustible mixture, temperature operated means for enriching the mixture when the temperature is low, and for leaning out the mixture when the temperature is high, said temperature enriching means being inoperative at high speeds.

2. In a suction operated spray carburetor,

threaded to deliver a richer mixture when the temperature is low, said last named means being inoperative at high suction.

In a carburetor, a thermally operated fuel controlling device comprising a flat strip of thermostatic material in the order of .017 of an inch in thickness, said strip having sufl'icient resiliency and flexibility to permit its being flexed by the suction of the carburetor as well as by change in temperature.

4. A thermally controlled device comprising two substantially parallel members joined by a cross member, one of said parallel members being formed of bi-metallic material and being entirely flat and straight, the other of said parallel members andsaid cross member being formed of a material that is substantially constant in shape under changes in temperature, a retaining device having a Wrench-receiving porn ion between the unjoined ends of said members, said wrench receiving portion having a side-port and an end-port, said side-port being open at ,all times and said end-port being controlled by the free end of the said bi-metallic material.

5. A thermostatic controlling device for carburetors comprising a body member having a fuel passageway therein, said passageway terminating in a seat-portion, the said passageway being enlarged and screwat its seat-portion, a U-shaped bracket having a perforation in one end thereof and seated on said seat-portion, a screw for holding said bracketin position, said screw having a longitudinal passageway therein and a transverse passageway communicating with said longitudinal pas- .sageway, the end of said longitudinal passageway being adjacent the free end of said U-shaped bracket.

6. In a carburetor, a heat-operated fuel controlling device comprising a body member having a fuel passageway therein, a seat surrounding the inlet of said fuel passageway, a U-shaped bracket mounted on said seat and having a perforation therein substantially concentric with said passageway, a screwthreaded member threaded to said body memher for holding said U-shapedbracket in po-,

s1tion,'said screw-threaded member having an opening adjacent to free end of said U, said end of said U comprising a heat responsive element.

In a carburetor, means forming a mixing conduit, a throttle valve controlling the flow of mixture through said conduit, means forming a constant level fuel supply chamber, a fuel conduit leading from said fuel supply chamber and having a main outlet into said mixing conduit'at a point anterior to said throttle, said fuel conduit having a low-speed branch discharging at one or more ports in the wallof said mixing conduit, said port or ports being located at a point adjacent "the edge of said throttle valve when it Leraeea is in closed position, said fuel conduit havin an inlet located below the fuel level in said constant level fuel chamber, and aheat operated valve for controlling said inlet.

8- In a carburetor, means forming a mixing conduit. a throttle valve controlling the flow of mixture through said conduit, means forming a constant level fuel supply chamber, a fuel conduit leading from said fuel sup- 'ply chamber and having a main outlet into main outlet and said low speed branch will be varied both by heat and by suction.

9. In a carburetor, a fuel chamber, a body member extending into said fuel chamber, a jet nozzle threaded into said body member and communicating with said fuel chamber, a bafiie carried by said body member adjacent the outer end of the jet nozzle, and a pivoted support for said baflie, the axis of said pivot being parallel to the axis of said nozzle, whereby the baffle may be turned aside to permit ready access to said jet.

10. In a carburetor, means forming a mixing conduit, a sin 1e fuel sup ly source, a connection for suppIying fuel from said source to said conduit, a calibrated passageway in said connection for metering the maximum quantity of fuel which it is desired to pass through said conduit, said connection having means to direct fuel from the same source through a plurality of paths from said source to said calibrated passageway, and a thermally operated device for controlling the passage of fuel through one of said paths.

' 11. In a carburetor, means forming a mixing conduit, a single fuel supply source, a connection for supplying fuel from said source to said conduit, a calibrated passageway in said connection for metering the maximum quantity of fuel which it is desired to pass through said conduit, said connection having means to direct fuel from the same source through a plurality of paths from said source to said calibrated passageway, said means including a calibrated flow re: stricting device in one 'of said paths, and a thermally operated device for controlling the How of fuelthrough the other of said paths. 7 12. In a carburetor, a. liquid fuel flow controlling device comprising a passageway having a pair of spaced calibrated flow restricting devices, means for causing the fluid to flow first through one of said devices, and 130 then the other, and thermally operated means for admitting or preventing the admission orifices when the temperature is low.

14. In a carburetor, means forming a mixing conduit, a fuel bowl, means for conveying fuel. from said bowl to said conduit, a metering orifice of comparatively large size in said conveying means, a metering orlfice of smallor size between saidlarge orifice and the fuel fuel bowl, conducting bowl, said small metering orifice being adapted to deliver fuel to said large metering orifice, means for by-passing fuel around said small metering orifice to said large metering orifice, and thermally operated means for controlling said by-pass, whereby fuel may be selectively metered at either of said metering orifices.

15. In a carburetor, a fuel chamber, a body member having a part extending into said fuel chamber, a jet nozzle carried by said part and communicating with said fuel chamber, a support held in position by said nozzle, a pivotally mounted heat controlled member carried by said support and held in position adjacent said nozzle thereby, said heat controlled member being adapted to be turned to OllBrSldB of said nozzle'on said pivot to :per-

mit ready access to said nozzle.

In testimony whereof I afiix my signature.

GEORGE R. ERIGSON.

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