US2310739A - Fuel supply and carbureting system for internal combustion engines - Google Patents

Description

Feb. 9, 1943. J LANG FUEL SUPPLY AND CARBURETING SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed June 27, 1940.

Patented Feb. 9, 1943 FUEL SUP?LY AND OARBURETING SYSTEM FOR ENTERNAL COMUSTION ENGINES Joseph C. Lang, Pittsburgh, Pa, assignor to Bocjl Corporation, Pittsburgh, Pa., a corporation of Belaware Application June 27, 1940, Serial No. 342,742

6 -Claims. (Cl. 261-21) This invention relates to .the fuel supply and carburetlng system of an internal combustion engine and is particularly designed for use in a carbureting system wherein fuel is supplied to a wick device from which it is evaporated by the stream of combustion air passing to the engine, the air thereafter being carbureted in a conventional carburetor. The present application is a continuation in part of my copending application Serial No. 285,298, filed July 19, 1989,

now issued as United States Patent No. 2,262,013, granted November 11, 1941.

In a copending application of Emery E. Phillips, Serial No. 211,090, flled May 31, 1938, there is disclosed a charge-forming device for internal combustion engines comprising an auxiliary carbureting unit in advance of the main carbureting unit, the auxiliary carbureting unit being provided with a curtain of absorbent material through which the air flows in passing to the main carburetor. This curtain of absorbent material is supplied with fuel so that .the air in passing through the curtain, vaporizes some of the fuel before it flows to the main carburetor. In my said application Serial No. 285,298 of which the present application is a continuation in part, I have claimed an improvement in the auxiliary carbureting device per se. In the auxiliary carbureting device disclosed and claimed in my said application'Serial No. 285,298, the absorbent material is wrapped about and carried by looped pipe which is perforated, the arrangement being such that fuel may be continuously supplied to one end of the looped pipe and continuously discharged from the other, some of the fuel in flowing through the pipe escaping through the openings in it onto the wick. I have discovered that by connecting the looped pipe, such as that used in the vaporizer of my said application, around the fuel pump of an internal combustion engine and a conventional carburetor into a branch pipe leading from the circuit in which the loop is included, it is not only possible .to supply both the booster and the carburetor with fuel from the pump at the same time, but that the system eliminates certain difliculties inherent in fuel supply stems using a pump. The present invention especially eliminates the formation of what is known as a vapor lock" in the fuel system.

My invention may be readily understood by reference to the accompanying drawing which illustrates certain preferred embodiments thereof and in which Fig. 1 of the drawing discloses more or less schematically an internal combustion engine with its carburetor and fuel pump and fuel supply tank and the auxiliary carbureting device, the latter being shown in a somewhat diagrammatic fashion with the fluid coil in perspective and other parts in section, the same being on the air intake of the conventional carburetor; and

Fig. 2 is a fragmentary showing of a modiflcation.

Referring to the drawing, A designates an internal combustion engine having a downdraft carburetor B which delivers the carbureted charge of fuel and air to .the engine through a manifold C, this arrangement being a conventional arrangement now commonly used on motor cars. The carburetor B is supplied with an upwardly extending air duct D. At the top of this air duct is mounted the auxiliary carbureting'device or auxiliary carbureting device designated generally as E.

The unit E comprises a bottom pan 2 preferably formed of sheet metal having an annular trough-like portion 3 therein. The pan 2 is provided with a centrally positioned cone portion 4 terminating in a cylindrical flange 5, the

I flange 5 being for attaching the device to the air duct D at the top of the carburetor. Within the cone i there is illustrated a spider 6 which supports a central pin or bolt 1 .that extends upwardly through the top of the device as shown.

Around the rim of the bottom pan 2 is an annular flange 2a.

Setting on the bottom pan 2 and fitted within the flange 2a is a cylindrical shell 8 having a number of windows or openings 9 formed therein, this series of windows extending entirely around the device and providing a large total of open area through which air can flow to the interior of the shell. Fitted over the top of the shell 8 is a cover member l0 having a flange Ilia that fits about the top of the shell and having a shoulder portion Illb against which the top of the cylindrical shell abuts. It is provided with an upwardly ofiset portion Ii and a flat top 52. The bolt 1 passes through the top I2, and a wing nut l3 threaded onto this bolt serves to tightly hold the bottom pan, the shell 8, and the cover member III in assembled relation. The structure may be readily dis-assembled upon removal of the wing nut l3.

Within the cylindrical shell or enclosure 8 is an air filter comprising concentric outer and v inner cylindrical screens l4 and It with a mass of loose filtering material l6 therebetween. This material is preferably copper scouring wool, but may be any other suitable non-combustible fibrous or porous filtering mass. The bottom edges of the screens l4 and I5 rest on the bottom pan 2 outside the trough 3, and the shoulder lob on the cover I engages the top edges of these screens. In this way the air filtering structure is maintained in position inside the cylindrical shell 8 and the pan and cover of course prevent the filtering material l6 from becoming displaced.

Spaced inwardly from the outer air filter is a second air filter and back-fire shield or screen comprising outer and inner spaced wire screens I1 and I8 between which is a mass of copper wool or other fire-resistant fibrous material, preferably metallic, l9. This inner air filter and back-fire screen is supported at its bottom on the bottom pan 2 on the portion thereof inside the trough 3 and outside the conical portion 4. The top of this inner filter and back-fire screen abuts against the top l2 of the cover member I0, and the screen is tightly confined against endwise movement between these two members. While the offset portion II prevents the inner screen from shifting radially and maintains its concentric with the outer air filter, it is important that the bottom of this back-fire screen be in tight contact with the pan 2 and that the top of this inner air filter or fire screen be tight against the lining on the top portion l2 of the cover l0 so that in the case of a back-fire in the carburetor sending a flame up through the down-draft duct into the space inside the inner air filter, this fiame cannot communicate or pass through any space either below or above the inner'air filter or back-fire screen, and as an additional guard against this, the top I 2 of the cover I0 is preferably provided with an asbestos cover 20 on the inner surface thereof. The asbestos covering 20 not only is an added guard against back-firing around the top of the inner air filter member, but has a dampening effect on sounds so as to make the structure operate more silently than where such material is not. pro- One end of the coil 26 is turned vertically downwardly and the other end 21 is also bent vertically downwardly. The two downwardly extending legs of the coils unit pass through the trough and pan 3 and the joint is soldered where these terminals of the coil pass through the pan. The coil is provided with numerous small holes at intervals therealong. Wrapped tightly about the coils 23 and 24 is a layer of fabric or wickforming material as best shown in Figure 4.

The fabric is formed of capillary fibres forming I a continuous wick about the two coils, glass wool preferably being used. Extending vertically between the two coils are vertical wick elements 29. The elements 29 are preferably formed by wrapping a continuous strand of corded wick material, preferably of glass wool, around one coil and then around the other in the manner shown in my patent above referred to to provide more or less regularly spaced strands. This is accomplished, for example, by wrapping the wick material once around the lower pipe and then extending it upwardly and wrapping it once around the upper pipe and thence back to the lower pipe, etc., this forming two series of vertically extending strands 29, one series being spaced inwardly from the other and one series being staggered with respect to the other. By forming the coils 23 and 24 in such manner that they tend to spring apart to a slight extent, this resilience may be relied upon to keep the strands 29 taut.

In operation, liquid fuel is forced into the terminal 26 and fiows first through the upper convolution of pipe and then through the lower one and discharges through the terminal 21. Some of the liquid escapes through the perforations along the length of the tubing, wetting the fabric layer 28. This in turn wets the capillary strands 29 causing the wicks to be kept continuously wet with fuel.

The fiow of air induced by the operation of the engine is drawn through the windows 9 through the outer filter where the air is broken up into very fine streams. The air then flows around and between the wicks or strands 29 and then flows through the inner filter and back-fire screen to the interior chamber of the device from 30 whence it is drawn down into the carburetor.

In order to maintain the circulation of liquid fuel through the coils as long as the engine is running, the coils are connected directly into the fuel pump system for the engine. The fuel supply line to the engine is designated 30, and 3| is the usual fuel pump. These pumps have a diaphragm which operates continuously when the engine is running. As ordinarily used, there is a flow of liquid, however, only when the carburetor float valve opens to permit the flow of fuel into the carburetor bowl, the pressure developed by the pump being of a very small order.

There is a pipe 32 leading from the pump to the carburetor float chamber. According to the present invention a coupling 33 is placed in the line 32 fromwhich leads a branch pipe 34 that connects through a union at 35 to the coil terminal 26. The other coil terminal 21 is provided with a union 36 to which is coupled a pipe 31, this pipe being coupled at its opposite end to a T 38 in the fluid supply line 30 leading to the pump. It will thus be seen that as long as the engine is operating, the pump 3| may continuously circulate fuel through this continuous loop or circulating system.

In some cases. as indicated in Fig. 2, it may be preferable to return the excess fuel directly to the fuel reservoir R rather than to the fuel line. This is advantageous because it permits any air which is entrapped in the fuel passing through the perforated coil to be discharged into the tank from which it can be vented. To this end I have shown a branch pipe 96 leading from the pipe 31 (not shown in Fig. 2) to the fuel reservoir R. In new car construction it may be convenient to have only a line going to the fuel tank, whereas in the equipment of existing cars it may be convenient to have the excess fuel returned directly to the line 30.

While much of the gasoline or fuel being thus circulated will stay in the circulating system, some of it will, of course, be discharged into the wick structure. It may be discharged into the wick structure at a rate greater than the rate at which it is consumed, as it is desirable to keep the wick structure quite wet. With this form of the invention, when the wicks become saturated, the excess fuel can drip from the wick structure into the annular trough! in the bottom pan 2. To exclude forei Particles that may fall down from the wick, a very fine mesh screen 81: is provided over the top of the drip trough 3. Connected to the annular trough 8 through a union 39 is a drain pipe 40 which is looped at M to form a trap, the discharge end of the pipe being connected at 42 to the return line 8?. Excess liquid supplied to the wick structure may thus be returned to the fuel circulating system, the trap 4! of course forming a seal to prevent the free induction of air into the system.

The arrangement described provides a relatively large area of wick for contact with the incoming air. The air stream is broken up into small currents by the first air filter. Practically all of the air is brought into intimate contact with some portion of the wick surface from which it evaporates fuel. The air, after picking up the fuel vapor, passes through the inner filter and back-fire screen which also diffuses the flow of air in such manner that the air is drawn into the structure substantially uniformly around the entire structure. The arrangement not only provides an efficient preliminary carbureting unit, but is an effective air cleaner as well. After the device has been used for a period of time, the cover can be removed and the two filtering elements can be lifted out and replaced, or

washed in gasoline, thus providing a filter which can be kept clean. The continuous fuel circulating system enables the wicks to be kept. abundantly wet, but no loss of fuel is occasioned even where an excess of fuel is supplied to the wicks. By providing what may be termed a shunt or looped fuel circulating system around the pump 3! and into which loop the carburetor is connected, the trouble heretofore encountered from vapor locks is eliminated. By providing a large area of wick surface and a large area of openings 9 for the inlet of air, the air does not move at two high a velocity over the wicks at any given point and the device operates to reduce the hissing or wind noise produced by the suction of the engine.

While I have shown means for collecting fuel which drops off the wick and which is not vaporized in the auxiliary carbureting unit and the pipe til-M for returning this excess into the fuel circulating system, it is possible by the use of a metering device at the inlet and outlet sides of the unit, and preferably at both points, to very accurately regulate the dampness of the wick and prevent any such excess. For example, by providing a manualLv adjusting metering valve 310. in the fuel return line 31, it is possible to prevent any liquid from flowing in the line 31 50 above the pipe T 42, and all of the fuel circulated by the pump and not consumed by the conventional carburetor will be forced out the openings in the coiled pipe 2|. In this case the wick will be very wet. By opening the valve 31a to its fullest extent there will be little pressure built up inside the perforated coil and the wick will be relatively dry. Intermediate stages can be determined by a proper setting of the valve 31a. Even more accurate control can be secured if there is another metering device in advance of the perforated coil. In the drawing, I have illustrated for this purpose a thermally responsive valve 86 in the line 34, but any other metering valve may be used in its place. The metering valve 88 illustrated has a valve stem 88 which is operated by a bi-metallic member 81. By proper regulation of the metering valves the reservoir or the intake side of the pumrg/ The pump will, therefore, never be working against a completely closed circuit as it is at the present time where the closing of the float valve in the carburetor completely shuts off the flow of fluid from the pump which, however, continues to operate. This churning of the fuel by the pump, together with the generation of vapors in the pipe leading from the pump to the carburetor when the temperature under the hood is quite high, gives rise to the blocking of the fuel supply to the carburetor known as a "vapor lock. Since some of the fluid is always kept in circulation through the use of the present invention, the formation of a vapor lock is avoided. At the same time the system disclosed hereinprovide means whereby both the conventional carburetor and the coil of the vaporizer are supplied with fuel as needed from a common fuel pump. The location of a metering device such as the valve 310. at the outlet side of the coil is particularly desirable in that it assures of the coil being kept sufllciently full of fuel to keep the wick wet and prevent air from being drawn into the system, whereas the provision of the metering orifice at the intake side of the coil without a valve in the outlet pipe may allow the pump to create a suction in the coil which will result in excess air being introduced into the line. By having the discharge side of the coil connected 0 directly to the reservoir instead of leading back to the fuel supply side of the pump, vapors and gases in the system are vented through the vent in the fuel tank. While I have shown and described certain preferred embodiments of my invention, it will be understood that this is by way of illustration and that various changes and modifications may be I made therein within the scope of the following claims.

I claim as my invention:

1. A fuel system for internal combustion engines comprising a carburetor having an inlet for engine combustion air, a contact device communicating with said air inlet, a fuel pump having an intake connection from a source of fuel and delivery means for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to said delivery means and its other end leading to a point in said system on the intake side of said pump, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admixture with the engine combustion air ahead of said carburetor, and means associated with said Perforated portion to establish intimate contact between said fuel and said combustion air. 7

2. A fuel system for internal combustion en- 75 gines comprising 9, carburetor having an inlet for engine combustion air, a contact device communi-V cating with said air inlet, a fuel pump having an intake connection from a source of fuel and delivery means for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to said delivery means and its other end leading to a point in said system on the intake side of said pump, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admixture with the engine combustion air ahead of said carburetor, means associated with said perforated portion to establish intimate contact between said fuel and said combustion air, and means for returning excess fuel from said contact device to a point in the system on the intake side of said pump.

3. A fuel system for internal combustion engines comprising a carburetor having an inlet for engine combustion air, a contact device communicating with said air inlet, a fuel pump having an intake connection from a source of fuel and delivery means for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to said delivery means and its other end leading to a point in said system on the intake side of said pump, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admix ture with the engine combustion air ahead of said carburetor, and wick means adjacent to said perforated portion to establish intimate contact between said fuel and said combustion air,

4. A fuel system for internal combustion engines comprising a carburetor having an inlet for engine combustion air, a contact device communicating with said air inlet, a fuel pump having an intake connection from a source of fuel and delivery means for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to said delivery means and its other end leading to a point in said system on the intake side of said pump, metering means in said loop for controlling fuel flow therethrough, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admixture with the engine combustion air r ahead of said carburetor, and means associated with said perforated portion to establish intimate contact between said fuel and said combustion air.

5. A fuel system for internal combustion engines comprising a carburetor having an inlet for engine combustion air, a contact device communicating with said air inlet, a fuel pump having an intake connection from a source of fuel and delivery means for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to said delivery means and its other end leading to a point in said system on the intake side of said pump, thermally responsive valve means in said loop for controlling fuel flow therethrough, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admixture with the engine combustion air ahead of said carburetor, and means associated with said perforated portion to establish intimate contact betweensaid fuel and said combustion air.

6. A fuel system for internal combustion engines comprising a carburetor having an inlet for engine combustion air, a contact device communicating with said air inlet, a fuel pump having an intake connection from a source of fuel and a branched delivery conduit for feeding fuel to said carburetor and said contact device simultaneously, said contact device having a tubular loop with one end connected to a branch of said conduit and its other end leading to a point in said system on the intake side of said pump, said loop having an intermediate perforated portion communicating with said air inlet for delivering fuel for admixture with the engine combustion air ahead of said carburetor, and means associated with said perforated portion to establish intimate contact between said fuel and said combustion air.

JOSEPH C. LANG.

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