US1625573A - Carburetor - Google Patents

Description

a `1 G25 7 Apnl 19 1927 w. T. SIMPSON s 3 CARBURETOR Filed Oct. 2l 1920 2 Sheets-Sheet. 1

I nvetorf Mrd ggf/??? W.

April 19, 1927. W. T. SIMPSON A V 1,625,573

v CARBURETOR Filed Oct. 2l 1920 2 Sheets-Sheet 2 Innen for.'

Ward Ziinon,

Patented Apr. 19, 1927.

UNITED STATES WARD T. SIMPSON, QF ANN ARBOR, MICHIGAN, ASSIGNOR, BY ASSIGNMENTS, TO

ALBERT G. DICKINSON, OF GRAND RAPIDS, MICHIGAN.

CARBURETOR.

Application filed October 21, 1920.

One object of my invention is to provide a fuel feeding system for automobiles, motor boats and the like in which a carburetor of the vacuum feed type is employed, having capacity to draw the fuel into its fuel. chamber directly from a tank located in a lower plane than itself.

Other objects of the invention will. appear from the following description:

In the accompanying drawings:

Fig. 1 is a side view of the fuel feeding system adapted for use on automobiles or the like.

Fig. 2 is a central vertical section of the f carburetor'.

Figs. 3 and 4 are details of auxiliary valves which will operate to alter the character of the fuel mixture, i

Fig. 5 is a detail view of the fuel ejection means.

Fig. 6 is a detail view of the seam of the float.

Figs. 7, 8 and 9 show details of the throttle valve operating means.

Figs. 10 and 11 are views of means for controlling the fuel supply.

Fig. 12 is a view of a modification of means for taking care of air which may enter the fuel chamber in ways which will appear hereinafter.

In carrying out the invention I maintain a vacuum in the fuel chamber which is higher than that in the engine manifold, by means hereinafter described, but it will be understood that I do not limit my invention in all of its aspects to this difference in the vacuum.

In these drawings 1 indicates the fuel chamber, 2 the mixing chamber, 3 the fuel ejection means, the fuel inlet valve and 5 the float."

The niiixing chamber consists of a tube which is straight throughout from its air intake end 6 to its upper end 7 at the engine intake. The throttle valve consists of a collar 8 surrounding the mixing tube and movable on said tube to and from a seat provided by a ring shaped member 9 which is fixed relativ-ely to the chamber. This seat member or ring is spaced apart from but lies opposite to the inlet end of the mixing tube and the lower rounded .edge of the throttle valve seats against this when closed. Opening of the throttle valve by moving same along; the tube E2 will. allow air to enter the Serial No. MEJIA?.

intake to the mixing chamber through the space between the valve seat and the end of the mixing tube. rIhe inlet end of the mixing tube is hevelled or flared. rfhe air tube of the ejector at .its base where it joins the valve seat ringr is provided with. a stream line formation 10, which will contribute to the ready entrance of the air into the mix-- ing tube, from which point the air passes uniformly along all sides of the centrally disposed fuel ejection means and along a straight course to the engine intake. The throttle valve being arranged at the inlet end of the straight tube forming the mixving chamber is anterior to the mixing chamber and ejector and the mixing chamber is unobstructed and of full width above the ejector so that no obstruction is offered to the free flow of the mixture and as its course is straight it will not be thrown against the sides of' the tube and thus no undue frictional resist-ance to the inflowing mixture will. be offered and thus its velocity will not be reduced. The mixture will not strike upon any surface across its path upon which the fuel therein can collect or precipitate. The fuel chamber is connected at its upper part through .an upwardly inclined slightly curved passage 11 with engine intake, the outlet from this passage being the annular space 12 around the mixing chamber tube and between it and the surrounding casing. Because the mixing tube extends across the passage 11 there will be a strong suction effect produced by the mixture, rushing from the mixing chamber into the engine intake, upon the said passage 11v and the upper space within the fuel chamber resulting in a high vacuum in the said chamber to lift the fuelv directly through the ,pipe 15% from a tank 14tlo'tated below theleyel of the carburetor, with the result that the carburetor will draw its supply of fuel from this low tank without the interposition of the well lknown vvacuum system. Any prccipitation of the fuel on the walls of the engine intake will be directed back into the fuel chamber, for it will be noticed that the lower wall of the passage 11 extends around the outside of the mixing tube at 15 and be yond the same to merge into the outer wall 16. The Wall 15 thus forms the floor by which preci itat-ion will be caught to drain back into tie fuel Chamb-en The passage 11 joins the easing at an enlargement thereof liti Lezama is thence deflected inwardly towards the center of the mixing' chamber and the high velocity of the air at the said restriction makes depression in a conical. area above the air tube. This depression exerts further pull ou the fuel to draw it from the fuel pipe. At (he top of the ejector the air tube is l'nfovided with a cone 30 which reaches up into the conical area of depression, providing a thin lip so that any liquid which may lodge here can pass ydown along the side of the cone and spread out over the horizontal surface 30 to the outer edge thereof, where it will meet the high velocity air and be carried into the mining chamber. These details are shown vparticularly in Fig. 5.

It will be noted that the construction and operation of this ejector are such that two conical areas of depression are induced over the outlet of the fuel tube 32 by the air flowineV by it at high velocity. one within the air tube and the other just above the air tube. That is to say, two such a reas of depression exist when the throttle valve 8 is at all open; only one exists when it is fully closed. The suction of these areas exerted on the fuel tube outlet when my construction is used is very much greater than is developed by any of the usual forms of fuel ejection means, as has been found by experiment and measurement, and it is at all times greatly ineXcess of any depression existing in the fuel chamber at any time. The delivery of fuel to the mixing chamber is therefore assured in ample quantity, in fact is at some points in the operation greater in volume than is desirable, and I have accordingly provided means to counterbalance or reduce the high proportion of fuel to air .in the mixture at certain times as found desirable.

For this purpose I provide, in one forni of my invention, a tube 33 extending to the l'uel conduit 32 at a downward inclination, having;` a globular formation at 33a with an air port 34, and a valve pin 35 having a shank mounted in the extension 36. This valve pin is adapted to seat against the tapered. part of the tube at 37 and it gages the size of the air inlet port.

lVhile l have referred to valve or pin 35 as a metering pin, it will be understood that this term 'is used for convenience and not be cause it controls fuel in the same way that so* called metering pins do. lt will be noticed that the larger the opening is at this valve the less fuel will be 'drawn from the fuel tube 32, instead of the greater amount, as is the case in ordinary practice. This is because the larger the amount of air which can pass into fuel conduit, the smaller will be the amount of fuel drawn from the pipe. The result is that While the outlet of the fuel pipe remains the same, the capacity of the ejectorto deliver fuel is not altered, but the quantity of fuel is reduced as desired by operating` the air metering pin 35.

The constructiol'l is such that no fuel 'vapor pockets exi st in the feed line between the fuel cl'ian'iber and the ejector in which fuel vapor may collect from the fuel and interfere with the proper feed.

i provide means for preventing air from the metering tube from being drawn back through the fuel conduit :into the body of fuel. This means consists of the ball check valve which is a rranged to move substantially horizontally, though at a slight incline, along the bottom of the chamber lf3 in which it is located, and against a stop 4G. The air would pass baci;V through the conduit at times due to the vacuum existinglr in the fuel chamber and the' check valve prevents this, and thus prevents fuel from being carried up with the air from the. top of the supply as it otherwise would, and to the intake, and thus interfere with the predetermined regulated feed of fuel which the mixture prf)portioningmeans are adapted to supply.

lt will be noticed that the tube 33 adjacent the pin is tapered from its open end inwardly. The pin is of the same diameter as the bore of the tube at the small end of the taper and the pin in closing the tube extends into the said bore at the small end of the taper, and across the inlet opening from the automatic valve 4l to cut ofi the air both through the outer end of the tube and the automatic valve, for starting purposes.

The globular formation 33 at the outer portion of the air metering tube provides a receptacle for catching any fuel which may be discharged back through the meten ing tube. This may happen on backward movement of the engine pistons.

I'fZZ-agr-Tn idling, at which time the throttle valve is nearly closed, the mixture may be made lean by introducing' air through the metering tube by retracting the n'ieteringpin 85. Any suitable connection may extend from the metering pin to the operators position, such as the wire or .rod 38. This air enters the fuel conduit and russes through the ejector fuel tulie and thus reduces the amount of fuel delivered by the ejector. This air added to that passing' through the air tube of the ejector from the atmosphere, and that which passes the throttle valve, will malte the mixture of proper proportions of air and fuel for idling purposes.

iSlta/rngmlfor starting the throttle valve is nearly closed and the metering pin substantially closes the air metering tube, thus substantially cutting off all inlet of air to the fuel conduit through the metering tube and thus a mixture rich in fuel will enter the mixing ehan'iber, the only air being that passing through the air tube of the ejector.

As soon as the engine is started, if idling is desirech the throttle valve being nearly closed, remains so and the metering` valve is opened tov let the. air flow into the fuel conduit'to lean the mixture therein.

For driving at wide open throttle the metering pin may be left in the same open position as for idling, because at this time the air passing through the throttle and around and along the outside of the ejector air tube, as well as through the open air tube, will produce a faster flow of mixture from the ejector, than when idling, to meet the requirements of the engine under driving` load.

If the requirements of the particular make of engine to which the carburetor is to be applied are such as to require a rich mixture for idling, T provide an automatic valvev mounted on the metering tube, the casing 39 of which is screwed onto a nipple 40 having a scat within it for the` valve member el which is normally held open by a pull spring l2 when the Vacuum in the mixing chamber is light, as when driving with wide open throttle, so that then the air may enter the metering tube through the port 43 of the automatic valve, so that a lean mixture will be produced.

lVhen idling, at which time the throttle is nearly closed and the vacuum in the mixing chamber is high, the pull of the. vacuum will close the automatic valve and the air thus being cutoff from entering the metering tube and fuel conduit, the mixture will be enriched, the adjustment of the metering pin not being changed.

In starting the tendency of this automatic supplemental valve will be to close, but as the vacuum in the carburetor is light when the engine is first turned over, this valve will not close entirely. lVhen, however, the engine has been started but is idling, with throttle nearly closed, the vacuum in the carburetor will be high and this y'alve will close andenrich the idling mixture by reducing the choking air supply lf it is desired to meet requirenients of certain engines by hayy g a leaner idling mixture than would be alfordefil by the apparatus ii'ivolving the use. of the metering valve alone, l would use the supplemental valve (Fig. l) on nipple lll), which will open dming idling against its spring pressure and lean the n'iixture and close automatically at wide open throttle and enrich the mixture.

If, through any cause, air should get into the fuel chamber and commingle with the fuel and pass up through the vacuum passage, carrying with it some of the fuel, a separation of the air from the fuel will be. effected in the passage l1 and space surrounding the mixing tube. The mixing tube itself, where it crosses the vacuum pasll, will act as a baffle against which the air and fuel will strile to induce this separating action and any fuel which is separated out will drain back into the fuel ch amber. j

The float is built up of two portions which have au airtight seam. This seam as shown in Fig. 6 is solderless. This is particularly important in combination vith the fuel chamber having its upper part connected vith the engine intake through the passage ll because in case of bach tiring the float will not be destroyed by the melting of a soldered joint.

I show in Fig. l() a modification of means for controlling the inlet of fuel through the fuel pipe by means of air acting as a choke thereon. This means acts in a manner somewhat similar to the air metering tube, before described, but it is modified in construction in that the air passes through the inlet port le controlled by a valve 44a, the air from said port passing into a chamber 44" in the ring forming the seat for the throttle valve, said ring being shown at 9". From the chamber leb a. tube, or plurality of tubes, 44 extend upwardly along the outside of the air tube of the ejector and at their upper ends these tubes are directed inwardly at a point above the upper end of the fuel tube and in a direction across the bore of the air tube. The upper tapered end of the air tube of the ejector is cut across to receive these air jet tubes. The effect of the air passing across the depression space within the air tube above the fuel tube will be to choke the discharge of the fuel in some measure, and thus metering of the fuel supply may be effected by regulating the valve 45. This air modifies the action of the air passing the restriction around the end of the fuel pipev and between it and the wall of the air tube.

Instead of the check valve between the fuel chamber and the air inlet from the air metering tube, T may employ other means for taking care of air which may pass down the fuel tube from the outlet of the metering tube.

This is shown in Fig. liavherein the lower end of the fuel pipe extends into a chamber l? which is lo Vated in the fuel chamber with its open upper end just above the fuel level.

The bottom of this chamber closed. It has a port t8 at its lower end admitting fuel from the fuel chamber, andthe lower end of the fuel tube gets its supply from the bottom of this chamber. Any air which comes down the fuel pipe will displace the liquid in this chamber and keep it substantially free from fuel at points above the lower end of the fuel tube, so that the air may escape up through the free space of the chamber and will strike a baflie surface at i9 on the casing above the level of the fuel, where any fuel which may be carried up will be separated from the air to fall into the body of the fuel, and thus no fuel will be carried oif through the vacuum passage to the engine manifold, the main purpose being to prevent the air from passing up through the body of fuel and carrying with it some of the fuel directly to the engine intake.

Cooperating with the elements of the earburetor above. described, including the vaeuum passage from the manifold to the fuel chamber and the float controlled inlet valve, l employ means for introducing air into the fuel supply pipe whereby the lifting of the fuel directly to the fuel chamber from a tank at a lower level is facilitated. The structure involving the mixing tube acting as a baffle across the mouth of the vacuum passage leading from the fuel chamber contributes to the use of air with a directly connected fuel chamber and supply tank, because this construction will take care of any fuel which passes oif with the air from the fuel supply in the fuel chamber through the vacuum passage. This fuel will be separated from the air by striking the baille and will run back into the body of fuel in the fuel chamber, to be drawn out through the ejector.

In carrying out this part of my invention, l provide an opening as at 55 or openings in the fuel pipe which extends down into the fuel tank so that as the fuel is drawn through this pipe air will also be drawn in and lighten the fuel column s0 that it can be lifted to the required height. This air will, of course, not be drawn in until the level of the fuel is below the opening` or openings referred to.

This air, of course, gets into the fuel chamber, passes through the body of fuel therein, and should any fuel be carried up with the air, it will be separated therefrom, particularly as it will strike against the side of the mixing tube or chamber acting as a bait-1e and this separated fuel will drain back into the fuel chamber through the said vacuum passage and will be available to be drawn through the ejector, and therefore will not alter the proportion of fuel to air by going directly to the engine.

It will be observed that an aspirating action takes place at the discl'iarge side of the annular passage l2 surrounding the milo ing tube by the velocity of the mixture pass ing from the discharge end of the mixing tube into the engine manifold, and this creates the higher depression in the fuel chamber.

lfVith my arrangement of mixing chamber without bends and with the ejector directed coaxially thereof and the annular valve, providing, when open, an annular air admission space about the base of the ejector, and uniform at all points, the flow of the air will be uniform at all points around the ejector and the anis of the mining tube, and there will be no variations in friction, and the engine intake or manifold will receive its supply uniformly to be distributed to the engine cylinders alike.

N ot only does my carburetor present 1naterial advantages from the standpoint of operation, but it has advantages from a manufacturing standpoint, by reason of its simplicity. The mixing chamber is simply a tube. The frame is provided with two openings in alignment with each other, in one of which the tube is seated, and projects therefrom, affording a guide and support for the throttle valve. The other end of the tube simply projects into the other opening, leaving an annular space l2 around it and it thus provides in a simple way an aspirating means for producing` higher depression in the fuel chamber than in the engine manifold. The valve seat and ejector support is" provided in a simple way by the ring shaped member, and this is carried by a bracket arm, forming a support or carrier also for the fuel pipe or conduit. This bracket with the ejector and valve seat and fuel conduit is removable as one unit, so that' the fuel conduit may be replaced with one of larger or smaller diameter and with an ejector to correspond, as may be necessary to suit different engines. This bracket also carries the air metering device as a part of said removable unit.

The outlet from the fuel chamber to the fuel conduit leading to the ejector is such as will prevent the collection of any vapor given od from the liquid fuel. For this purpose the wall of the fuel chamber at 50 is inclined downwardly at such an angle that at no time in traversing steep grades will there be formed a pocket at this point in which vapor given off from the fuel will collect, and by its expansion and contraction interfere with the feed of the fuel.

Tt will be clear from the foregoing description that when the depression throughout the carburetor and manifold is lat its minimum, i. e., at wide onen throttle, I maintain a high degree of vacuum in the fuel chamber to draw fuel thereinto from a low level tank. During idling the depression in the manifold and fuel chamber is high, and ample to perform this function, although the same ratio of difference in the depression between the manifold and fuel chamber does not, and need not, exist at this time, as compared with that which must exist during wide open throttle.

By my construction the natural minimum depression in the engine manifold and carburetor fuel chamber, for example, at open throttle at low revolutions, is wholly vretained and in addition I employ means that will create a still greater depression than the natural minimum, by creating an ejector force at the vacuum connection above the ejector.

The float, the inlet valve, the housing for the valve, the support and pivotal mounting for the float and the inlet nipple, are combined as a unit capable of removal or replacement as such, and capable of being assembled and tested before mounting it on the frame of the carburetor. The opening through the ywall of the carburetor is large enough to take in this float.

The globular formation 33 at the outer port-ion of the air metering tube provides a receptacle for catching any oil which may be discharged back through the metering tube. This may happen on backward movement ef the engine pistons. j

Having thus described -my invention, what I claim is l. A fuel supply system for internal combustion engines, comprising a fuel chamber to receive fuel from a lower level tank, a float valve controlling said supply, a mixing lchamber in communication at one end with the 'engine intake, a fuel ejector extending into the other `end of the mixing chamber and connected with the fuel chamber, said fuel chamber having communication above its fuel level with Vthe engine intake to be subjected to the vacuum depression of Vthe engine intake, a valve seat arranged opposite and spaced apart from the the end of the mixing chamber vwhere the ejector is located to leave an annular air inlet space, and a sleeve valve movable in relation to said mixing chamber from its closed position against said seat, said ejector, mixing chamber, engine intake, and valve-'being axially in line, and the -air Itube of said ejector having an outwardly flaring Lipper end to make a restricted space between itself and the mixing chamber wall, in order to give greater velocity to the secondary air, thus intensifying the degree of vacuum induced by same over the fuel tube, substantially as described.

2. In combination in a vacuum feed carburetor, an air-tight fuel chamber connected with 'a 'low level tank and having a suction passage leading from above its fuel level to the engine intake and whose axis is substantially perpendicular to that of ythe intake vat their juncture to subject the fuel chamber to the suction of the engine to draw fuel into the fuel chamber, a float valve in the fuel chamber, a mixing chamber directed 'to the engine intake and extending beyond the substantially horizontal opening of the suction passage so that the effect of pulsations existing in lthe suction passage on the stream of mixture moving through the mixing chamber to the intake will be balanced as regards said stream of mixture, and an .ejector directed axially of the mixing chamber and having its upper end below said suction passage.

In combination in a carburetor, a mixing chamber, a fuel ejector comprising an air tube flared at its upper end, open at its lower end to atmosphere, and `'extending' axially of the mixing chamber, said air tube having 'a flared tip and together with the wall of the mixing chamber defining a restriction in the mixing chamber adjacent said flared tip, and a fuel pipe within and below the upper end of the air tube having a flared upper end forming between itself and the wall of the air tube a restriction, said restrictions inducing higher velocity of air `at the poi-nts where they are located and consequently a greater degree of vacuum over the end of the fuel pipe, and a valve for controlling 4the air to the space between the mixing chamber wall and `the air tube, and a fuel chamber subject to the depression in the manifold.

4l. In combination in a carburetor, a mixing chamber, an air tube extending into the same, a member arranged opposite and spaced apart from the intake of the mixing chamber, said member constituting a seat for an annular valve which controls the admission of air into the mixing chamber between said member and the end of the mixing chamber, said air tube opening to an air supply through said member, a fuel pipe extending into `the fair tube terminating below the top of the same and flared-outwardly to provide a restriction of 'the passage lof air between itself and the wall of the air tube, the said air tube -at its outer side being flared outwardly 4to form a restriction to the passage of air between itself and the wall of the mixing chamber, substantially as described.

5. In combination in a carburetor, a mixing chamber, an ejector comprising an air tube extending into the same, a valve seat arrangedopposite and spaced apart from the intake of the mixing chamber, an annular valve to admit air into the mixing chamber, said air tube opening to an air supply thro-ugh said seat, a fuel pipe extending into the air tube `terminating below the top of the same and flared voutwardly to provide a restriction between itself and the wall of the air tube, the said air tube at its outer side being liared outwardly to form a restriction between itself and the wall of the mixing chamber, vand producing a conical area of depression at the end of the ejector, the tip of air tube being conical to extend into said depressed area, and a substantially horizontal ledge at the base of said conical extension.

6. In combination in a carburetor of the kind described, an unrestricted passage from the discharge end of said carburetor to the constant level reservoir to subject the latter to the vacuum created by an engine in order to raise fuel to the reservoir, a. mixing chamber, an ejector directed to the mixing chamber to deliver fuel thereto from the reservoir, and means to admit air to the fuel tube of the ejector consisting of two cooperating valves of the metering pin type, the one being manually controlled, the other automatic, to assist the ejector in properly ro )ortionino the mixture of fuel and air.

by counter-balancing the effect of certain variations in the differential in pressures between the reservoir and ejector head.

7. ln combination in a carburetor, an open passage from the discharge end of said carburetor to the constant level reservoir to subject the latter' to the vacuum created by an engine in order to raise fuel to the reservoir, a mixing chamber, an ejector directed to the mixing chamber to deliver fuel thereto from the reservoior, and means consisting` of two cooperating valves, one manually controlled, the other auton'iatic, to admit air to assist the ejector in proportioning the mixture of fuel and air, substantially as described.

8. In combination in a carburetor, a fuel chamber, a mixing chamber, a fuel conduit leading from the lower part of the fuel clnimber and terminating` in a nozzle directed to the mixing chamber, a throttle valve, and metering means consisting of an air conduit connected with the fuel tube to supply air thereunto and a metering pin for regulating the opening through said metering tube, and an automatic air valve operated by the suction in the mixing chamber for controlling air to the fuel conduit, substantially as described.

9. ln combination in a carburetor, a fuel chamber, a mixing chamber, a fuel conduit leading from the lower part of the fuel chamber and terminating),- in a nozzle directed to the mixing chamber, a throttle Valve, and metering means consisting of an air conduit connected with the fuel supply tube to supply air thereunto and a metering pin for regulating the opening through said metering tube, a nipple through which air may pass to the fuel tube, and valves removably adapted to said nipple, said 'Valves being controlled automatically by the suction of the engine, substantially as described.

10. ln a carburetor, a fuel chamber, a i'nixii'ig chamber having at its outlet end a coaxial passage communicating With the engine, aI fuel ejector, and a Vacuum passage communicating said coaxial passage With the fuel chamber, the Wall of said mixing chamber acting as a baflie for said vacuum passage and to cause engine pulsations to take place parallel with the axis of the mixing` chamber, substantially as described.

ll. ln combination, Va carburetor having a fuel chamber, an ejector drawing fuel therefrom, a passage connecting the fuel chamber with the manifold of the engine whereby said fuel chamber' is subjected to the depression at the manifold and also to the pull of the ejector, a fuel tank, a pip( extending therefrom to the fuel chamber, and bailie means extending across said Vacuum passage and consisting of the mixing chamber Wall, substantially as described.r

l2. ln combination with a fuel chamber, a mixing' chamber, a passage extending yfrom the upper part of the fuel chamber and in communication with the engine intake through an annular passage surrounding the upper part of the mixing chamber, the lower Wall of said passage fitting close about the mixing tube and forming a drain surface and conducting the fuel back into the fuel chamber, substantially as described.

13. ln a carburetor of the hind described, a mixing chamber, a fuel chamber subject to the suction of the engine through a pasleading thence to the mixingchamber. the juncture of said passage with the mix ing chamber being so arranged that the :lion of mixture passing through the mixing chamber will, by aspiration, induce in the fuel chamber a higher degree of vacuum than exists in the mixing chamber to assure the supply of fuel to the fuel chamber, and means for delivering fuel into the mixing chamber.

14. ln combination in a carl'iuretor, a fuel chamber, a tubular connection extending therefrom, having aligning openings, a mixing tube seated in one opening and directed to the other opening` with an annular space between to communicate said tubular connection and fuel chamber With the engine manifold, means to direct fuel into the mixing chamber, a member arranged opposite and spaced apart from the end of the mixing tube and an annular valve operating in comiection With said member, substantially as described.

ln testimony whereof, I affix my signature.

WARD T. SIMPSGN.

Images