US1443343A

US1443343A - Carburetor

Info

Publication number: US1443343A
Application number: US256794A
Authority: US
Inventors: Milford G Chandler
Original assignee: CURTIS B CAMP
Current assignee: CURTIS B CAMP
Priority date: 1918-10-04
Filing date: 1918-10-04
Publication date: 1923-01-30
Anticipated expiration: 1940-01-30

Description

M. G. CHANDLER.

CARBuREToR'. F1 LED OcT. 4, 1918.

2 SHEETS'SHEET I Jan. 30, 1923. 1,443,343

M. G. CHANDLER.

CARBURETOR. FILED 001'. 4, 1918. 2 SHEETSSHEET 2 Patented Ian, 30, I923.

, insane QFFICEO- MILFORD G. CHANDLER, OI CHICAGO, ILLINOIS, ASSIGNOR, BY'MESNE ASSIGNMENTS,

TO LYNN A. WILLIAMS, OI EVANSTON, ILLINOIS, AND CURTIS B. CAMP, OI CHI- CAGO, ILLINOIS, JOINT TRUSTEES.

CARBUEIIIOR.

Application filed @ctober t, 1913. Serial No. 256,794.

To all whom it may concern:

Be it known that I, MILFORD G. CHANDLER, a citizen of the United States, residing at Chicago, in the county of (00k and State of Illinois, have invented a certain new and useful Improvement in Carburetors, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to carburetors of the suction type wherein the fuel is lifted from a low level supply tank to the carburetor body by the suction of the suction producing means for the carburetor.

In my Patent No. 1,370,949, dated March 8, 1921, I have disclosed one means by which a greater suction is made available for lifting fuel to the carburetor than that which exists in the mixing chamber of the carburetor and in the intake manifold of the engine. In said patent, I have fully set forth the reasons why advantages are derived from the provision of'means for enhancing the manifold suction for fuellifting purposes, and the reasons therein set forth apply equally well to the carburetor of my present invention which is a modification of and an improvement upon the carburetor of my patent above identified.

In accordance with my her ein described invention, I provide an auxiliary Venturi tube leading from the external atmosphere into a region of depression within the carburetor, the only function of which Venturi tube is to maintain a fuel lifting suction upon the surface of the fuel in the carburetor reservoir, a second or nozzle Venturi tube be ing provided for delivery of fuel into the body of the carburetor, this second Venturi tube likewise leading from atmosphere into a region of depression within the carburetor, but having its delivery end located in a region within suction is enhanced by the How of air through a large Venturi tube forming the main passageway for air to the engine.

In order that the suction produced in the fueh reservoir may be sufficient to lift fuel from the low level supply tank to the car; buretor, even under the adverse conditions of a nearly closed throttle, the combined areas of all of the air passageways into the body of the carburetor, under the conditions the carburetor wherein the- It has been found that the discharge of fuel into the nozzle Venturi tube greatly decreases what may be termed as the suction efficiency of the nozzle Venturi tube, and that the greater the amount of fuel delivered to the throat of the nozzle Venturi tube, the more nearly the suction at the throat appreaches the suction at the discharge end of this tube For thisreason, it has been found important that the nozzle Venturi tube discharge into the carburetor body at a region in which the suction increases with the flow of air'through the carburetor, while it is also important that the suction producing Venturi tube discharge into the carburetor body at. aregion in which the. suction does not materiall flow of air. fly this means and by the provision of an impinging opening for the discharge end of the suction Venturi tube, I am able to maintain a substantially constant suction within the fuel reservoir for lifting fuel, while the suction on the discharge end of the nozzle Venturi tube is caused to increase with the increased flow of air through the carburetor in such proportions as to provide a proper mixture of fuel and air through the entire range of the engine from its lowest to its highest demands.

A still further feature of my invention is the provision of a duct adjustable in size leadingfrom a point on the engine side of the main carburetor throttle to openings at an intermediate point along the suction Venturi tube, this passage providing means for securing a slightly higher draft through the suction Venturi tube than would otherwise obtain when the engine is idling, thus providing a convenient means for adjusting the mixture of fuel and air for idling conditions of the motor. This is of importance because the amount of air which is admitted to the intake manifold of an internal increase with the increased combustion engine around the stems of the intakevalves varies as the valve stems and their guides become worn. The amount of air which is delivered around the valve stems is so small that it does not materially affect the mixture of fuel and air for any other speed than idling, but since the suction in the intake manifold is highest at idling and the quantity of mixture used by the'engine is the least, the 'efi'ect of-the leakage around the valve stems becomes a real factor in adjustment for pro or idling conditions.

My invention 18 illustrated in the accompanying drawings, in which- Figure 1 is a vertical section through the main body of the'carburetor; and

, Figure 2 is an elevation of the portion of the carburetor'adja-cent the engine, with the induction portion removed.

Like characters of reference refer to similar parts in each of the figures.

The body of the carburetor comprises three main castings 3, 4c, and 5, fittedtogether and forming the carbureting section,

theinduction section, and a section forming a housing for a piston operating an air valve. ast integrally with the carbureting section is the float chamber or reservoir 6,

provided internally with any suitableform of float controlled valve mechanism for maintaining the level of the fuel in the float chamber slightly. below the lowest of the fuel delivery ports 7. The float chamber 6 is sealed against atmospheric pressure. It is, however, provided with three openings, one of which passes through the revolvable member 8 which is connected with the main low level supply tank, another of which is indicated at 9 and'serves to feed fuel to the ports 7, and the third of which is indicated.

at 10 and serves as a means for creating a artial vacuum on the surface of the liquid in the float chamber for lifting fuel from the low level supply to the float chamber.

The effective size of the assage 9 is controlled by a valve 11, whic as hereinafter more fully described, regulates the fuel to the ports 7. Within the main air passage of the carbureting section 3 is the usual throttle 12,'vvhich is provided with an adjustable stop (not shown), to limit the movement towards the vertical, so that the throttle isnever closed beyond that position which will supply the engine with sufhcient explosive mixture for its lowest idling speed. Anterior to the throttle 12 is a large Venturi tube 13 and a smaller Venturi tube 14, together forming the induction passage for the major ortion of the air and mixture. The smaller e'nturi tube 14 has its anterior opening connected directly with atmosphere through the passageway 15, Whereas the anterior opening of the large Venturi tube 13 is connected with the passageway 16, which has its atmospheric communication restricted by the butterfly valve 17 The valve 17 is pivoted at 18 and is operated by a link 19, which connects with a piston 20 operating in the oylinder 21 formed by the housing 5. The piston 20 is held towards its normal position by a spring 22, which acts through the link 19 to hold the valve 17 normally in closed position. The cylinder 21 is connected through registering passages 24, 25, 26 and 27, through the castings of sections 5, stand 3, and through the wall of the large Venturi tube 13 with the air space of the carbureting section 3. This air space between the passage 27 and the throttle 12 'will hereinafter be referred to as the mixing chamber, since it is in this space that the combustible mixture of gasoline and air is formed. It is to be noted that the opening 27'is located ata point in the large Venturi tube substantially at the throat thereof, this being near the position of maximum partial vacuum in the venturi 13. The small Venturi tube 14: has its delivery opening located slightly nearer the delivery end of the Venturi tube 13than the position of the openings 27, the position of the delivery end of the nozzle Venturi tube 1 1 however, being likewise substantially in the region of maximum partial vacuum of the Venturi tube Il3.- The nozzle Venturi tube 14: is made of such a size that for the slowest idling speed of the engine, with the throttle 12 substantially closed, the air will be drawn through the opening of the nozzle venturi 14 at sufficient speed to create a partial vacuum on the ports 7 to cause a deive'ry of fuel into the nozzle venturi 14 through the ports 7, notwithstanding a partial vacuum on the fuel in the float chamber suflicie'nt for lifting fuel from the low level supply tank to the float chamber. It has been found in practice that with a construction having angles and proportions substantially as shown in the accompanying illustration apartial vacuum suficient for lifting gasoline through a, distance of forty inches will be created at the ports T when the partial vacuum in the mixing chamber of the carburetor is only sufficient for lifting gasoline fifteen inches. The nozzle Venturi tube 14 is abruptly enlarged at 30 just anterior "to the point at which the fuel enters the Venturi tube. This sudden enlargement adds greatly to the suction differential of the Venturi tube, probably for the reason that a portion of the fuel becomes actually gasified or vaporized immediately upon its deliverance into the throat of the Venturi tube 1-1. By reason of this gasification of a part of the liquid fuel the mixture tends to suddenly increase in volume within the small Venturi tube 14 and unless space is provided for it. a pressure is created which partially counteracts the vacuum which is created at the throat of the Venturi tube when no additional vapor is admitted. The depth of the llll step in the Venturi tube depends somewhat upon the volatility of the fuel used.

The carrier 32, into which the nozzle Venturi tube 14 is threaded, is supported in the axis of the mixing chamber by means of the

webs

33 and 34, theweb 33 providing the walls of the conduit 9 for conveying the gasoline from the float chamber to the ports 7.

In order to maintain an enhanced partial vacuum upon the surface of the fuel in the float chamber a very small Venturi tube 35 is provided connecting between atmosphere and the region anterior to the throat of the Venturi tube 13. The throat of the venturi 35 is provided with suction openings 36, which connect through the passage 10 with the upper space of the float chamber 6 to create throat suction on the fuel for lifting purposes. The posterior end of the venturi 35 is provided with a lateral opening 37, which may be adjusted at any angle to the direction of flow of air through the entrance to the large Venturi tube 13. The impinging effect of the air as it strikes the opening 37 decreases the effectiveness of the small venturi 35, thus preventing the partial vacuum in the float chamber from unduly increasing as the vacuum in the space with which the end of the venturi 35 communicates increases with the volume of air passing through the carburetor.

It has been found that at lowspeeds, and particularly with the throttle 12 substantially closed, the mixture of gasoline andair passing through the small venturi 14 so nearly approaches a combustible mixture, that the self-regulating features of the carburetor heretofore described do not properly function and unless some provision were made to prevent such an action, the suction at the front of the nozzle Venturi tube would be so much greater than the suction at the throat of the vacuum- Venturi tube that the mixture would become too rich. This di'liiculty arises principally from the fact that the richness of the mixture of. gasoline and air in the Venturi tube 14 has dropped so low, due to the decreased velocity of air through the Venturi tube, that the Venturi tube 14 is now producing a throat suction which is enhanced over the suction at the discharge end of the Venturi tube by a greater percentage than the enhancement which occurs during larger engine demand, wherefore the automatic regulating effects heretofore described have substantially disappeared. In order to prevent overrichness of the mixture at these low speeds, it is found expedient to produce a slightly higher suction on the surface of the fuel in the float chamber. This is brought about hv means of a passage 37 communicating through ports 38, with an intermediate position along the tube of the venturi 35.

excess of the vacuum necessary for lifting the fuel. An adjusting screw 39 is provided in the passage 37, by means of which'a proper vacuum for the best idling can be secured. The greater the amount of air permitted to pass the adjustment point, the greater the vacuum created in the float chamber and the more lean the mixture delivered to the engine.

I have'found that a carburetor constructed as herein described not only regulates itself automatically-for different speeds and operating conditions, but also regulates itself for different temperatures of fuel and air. If the fuel or air, or both, are .hot when they enter the small Ventum tube let, there is a more rapid volatilization 'of the fuel than when the fuel or air or both 1 are cold. This rapid volatilization of the fuel decreases the suction differential of the small Venturi tube 14 and thus causes it to deliver a less amount of fuel, it having been determined that if the fuel and air are hot, by reason of the more perfect atomization and volatilization of the fuel, an engine' will run satisfactorily on a leaner mixture than if the fuel and air, or either of them, is cold. This latter regulation is brought about by the size of the step 30. The step 30 is made the proper size to secure the greatest suction differential from the small Venturi tube when both the fuel and air are cold. Therefore, a quantity of fuel which is proper for the best running conditions is mixed with the air when starting, and as the engine heats up and the air and .fuel become warmer, the suction differential of the Venturi tube ledecreases at substantially the correct rate to maintain a proper mixture, notwithstanding the heating of the fuel and air. By reason of my construction of the nozzle Venturi tube 14 T have found it unnecessary to provide additional adjusting devices for obtaining rich mixtures for starting, as the mixture will au- 'tornatically become leaner as the engine heats up.

It is to be understood that the air induction opening for this carburetor may be connected with a hot air pipe running from some of the heated parts of the engine. as 124) is customary on automobile engines. The induction section 4 of the carburetor is arranged so that it can be turned to any one of four angular positions around the axis of the carburetor mixing chamber. All of 125 the openings 26 extending into the carbureting section are screwthreaded and the induction section a is provided with two diametrically opposite screws such as 41, which will enter two of the diametrically oppoit is to be understood that certain. of the details herein illustrated may. be varied without affecting the general operation of the device as a whole, and that certain of the details are applicable to other types of carburetors than the one herein illustrated, and that therefore I do not wish to be unduly limited to the specifically illustrated structure.

I claim:

1. In a carburetor the combination with a reservoir, of a fuel delivery tube provided with a fuel delivery orifice connected by a passageway with the lower part of said reservoir, and a smaller tube of venturi shape having an orifice connected with the upper spaces of said reservoir.

2., The combination with the fuel reser voir of a carburetor, of a small Venturi tube having its outer end exposed to atmosphere and its inner end positioned at an angle to the line of flow of air through the carburotor, the inner end of said Venturi tube being provided with an impact opening facing into the stream of air, so that the higher the velocity of flow of air through the carburetor the greater the impact and conseguently the less the flow of air through said enturi tube, and a connection between the throat of said Venturi tube and the upper part of said fuel reservoir and means to: deliver fuel from the reservoir to the air passing through the carburetor.

3. In combination with the fuel reservoir of a carburetor, of a small Venturi tube for the passage of air into the body of the can buretor, a duct from the throat of said Venturi tube to the upper part of the reservoir, the inner end of said Venturi tube standing at an angle to the path of movement of air through the carburetor and being laterally cut away, said Venturi tube being rotatable so that the impinging effect of the air upon the laterally cut away portion of the Venturi tube may be increased or diminished in accordance with the rotative position of the Venturi tube and means to deliver fuel from the reservoir to the air as it passes through the carburetor.

4t. in a carburetor the combination with the body forming a main passa eway, of a Venturi tube positioned in said body and having its inner end at an angle to the line of dow of air through said passageway, said Venturi tube being laterally cut away at its inner end and being rotatably mounted so that its cut away portion can he turned more masses or less squarely into the line of flow of air to increase or decrease the effectiveness of said Venturi tube and means to deliver fuel from the reservoir to the air as it passes through the carburetor.

5'. In combinationwith the body of a carburetor, of a posterior throttle therefor, a main air passage through the body ofthe carburetor, a venturi tube extending into said passage, a fuel reservoir, a suction connection from the throatof said Venturi tube to the upper part of said fuel reservoir, a duct from a point posterior to said posterior throttle to an intermediate position along said Venturi tube, the inner end of said Venturi tube being exposed to the carburetor suction anterior to said throttleand means to deliver fuel from the reservoir to the air as it passes through the carburetor.

6. The combination with a carburetor body, of a fuel reservoir, a posterior throttle, a Venturi tube extending between the external atmosphere and the main passageway for the carburetor anterior to the said throttle, a suction connection between said Venturi tube and the upper space ot said reservoir for creating a partial vacuum in said reservoir, a suction connection between an intermediate point in said Venturi tube and a point posterior to the said throttle, whereby the passage of air through said Venturi tube will be partially efi'ected by the suction posterior to said throttle and partially edected by the suction anterior to said throttle, and means to deliver fuel from the reservoir to the air as it passes through the carburetor.

7., In a carburetor the combination with a main body portion forming the main air passageway through the carburetor, of an anterior valve and'a posterior throttle in said main passageway, a Venturi tube extending into the space between said valve and throttle and having its outer end exposed to atmospheric pressure, a fuel reservoir, a connection between a point near the th'roatot said Venturi tube and the upper space of said fuel reservoir, and a. second connection between an intermediate position in said Venturi tube and a point posterior to the posterior throttle and means to deliver fuel from the reservoir to the air as it passes through the carburetor.

8. in a carburetor the combination with a main body oortion formingthe main air passageway through the carburetor, of an anterior valve and a posterior throttle in said main passageway, a Venturi tube extending into the space between said valve and throttle and having its outer end exposed to atmospheric pressure, a fuel reservoir, a connectionbetween a point near the throat of said Venturi tube and the upper space of said fuel reservoir, and a second connection between an intermediate posi Lil llO

llfi

tion in said Venturi tube and a point posterior to the posterior throttle, and means for adjusting the opening thereof and means to deliver fuel from the reservoir to the air as it passes through the carburetor.

9. In combination in a carburetor for an internal combustion motor, a fuel reservoir adapted to be supplied with fuel by suction, an induction passage having a throttle therein, a Venturi tube having an atmospheric inlet and a discharge opening communicating with the induction passage on the engine side of the carburetor throttle, a duct between the throat of said Venturi tube and the upper part of said fuel reservoir, and means for delivering fuel. from said reservoir into the stream of air as it passes to the manifold of said motor.

10. In a carburetor for an internal combustion engine the combination of a fuel reservoir adapted to be supplied with fuel by suction, an induction passage having a throttle therein, aVenturi tube having an atmospheric inlet and a discharge opening communicating with said induction passage of said motor at a point on the engine side of said throttle, a duct extending from the throat of said Venturi tube to said reservoir for creating suction therein, manually operable means for adjusting said discharge opening from said Venturi tube, and means to deliver fuel from said reservoir to the air passing. through the carburetor to said motor.

11. In a carburetor for an internal combustion motor, the combination of a large Venturi tube through which the major portion of the air for the operation of said motor passes, a nozzle Venturi tube having a discharge port located in the region of highestsuction in said large Venturi tube,

the intake of an internal combustion motor,

the combination of a manually operable throttle for said carburetor, a large Venturi tube through which the .major portion of the air for suppl ing said motor passes,

a nozzle Venturi tu e having one end subjected to atmospheric pressure and having the other end discharging substantially at the point of highest suction in said large Venturi tube, a fuel reservoir, the throat of said nozzle Venturi tube being connected with the lower part of said fuel reservoir for delivery of fuel to the carburetor, an automatic air valve restricting the inflow of air to the induction end of said large Venturi tube, a third Venturi tube discharging into the interior of the carburetor between said auton atic air valve and thecarburetor throttle, and a connection between the throat of said third Venturi tube and the upper part of said reservoir for creating suction therein for lifting fuel thereto.

13. A device for lifting fuel and delivering it in atomized form to a stream of air for supplying an internal combustion engine with combustible mixture, including in combination an induction passage, means to create a static suction in said passage, means to create a greater suction in a part of said passage due to air velocity, a fuel reservoir, a fuel delivery Venturi tube discharging in the part of said passage in which the greater velocity suction exists and having a fuel port discharging at the region of high suction therein said port being connected by a passage with said fuel reservoir below the level of fuel therein, a second Venturi tube discharging into a region of less suction in said passage and having a port located at a region of high suction therein connectedwith said reservoir at a point above the fuel level therein for creating suction for lifting fuel to said reservoir, and means to maintain a'substan tially constant level of fuel in said reservoir.

14. In a carburetor, a chamber adapted to be connected with the intake of an internal combustion engine, three Venturi tubes discharging into said chamber, and each having a constricted portion at which a depression obtains when the pressure in said chamber is reduced, a liquid fuel reservoir, :1 assageway for liquid fuel leading from be ow the level of fuel in said reservoir to a constricted part of one of said Venturi tubes, said Venturi tube discharging into a constricted part of a second Venturi tube, a passageway leading from above the liquid fuel levelin said reservoir to a constricted part of said third Venturi tube, and an automatic valve to limit the admission of air to said second Venturi tube.

' 15. In combination with the fuel reservoir of a carburetor, of a small Venturi tube for the passage of air into the body of the tor, and means other than said Venturi tube to deliver fuel from the reservoir to the air as it passes through the carburetor.

16. In combination with the fuel reservoir of a carburetor, of a small venturishaped passageway for the passage of air into the body of the carburetor, a duct from the throat of said venturishaped passage-- way to the upper part of the reservoir, means dependent upon the suction in the body of the carburetor for automatically regulatingwhe velocity of the air stream flowing through the throat of said venturishaped passageway with respect to the velocity of the flow through the body of the carburetor, manually operable means for regulating the velocity of the-air stream flowing through the throat of said venturishaped passageway, and means other "than said venturi-shaped passageway for delivering fuel from the reservoir to the air as it passes through the carburetor.

17. In combination with the fuel-reservoir of a carburetor of a small venturishaped passageway for the passage of air into the body of the carburetor, a duct from the throat of said venturi-shaped passageway to the upper part of the reservoir,

means independently operable manually for regulating the velocity of the air stream