US1838137A - Direct fuel feeding system - Google Patents

Description

Dec. 29, 1931. w. EDWARDS 1,838,137

DIRECT FUEL FEEDING SYSTEM Filed 001:. 3, 1928 2 Sheets-Sheet 1 j/f/"ZAM @WWQMMF Dec. 29, 1931. w EDWARDS 1,838,137

DIRECT FUEL FEEDING SYSTEM Filed Oct. 3,. 1928 2 Sheets-Sheet 2 35 35 Zfizfiaxs I fwyev zzar WMM E z/zzzlmdzza ms Patented Dec. 29, 1931 UNITED STATES WILLIAM .A. EDWARDS, OF CHICAGO, ILLINOIS DIRECT FUEL FEEDING SYSTEM Application filed October 3, 1928.

The purpose of this invention is to provide a fuel feeding system foran internal combustion engine of an automobile or other engine operated vehicle, by which the fuel may be fed to the engine by engine suction directly from a main fuel tank which may be carried in the usually preferred position at the rear end of thevehicle or at other position relatively distant of the engine. It consists in lo the elements and features of construction shown and described as indicated in the claims.

In the drawings:

Figure 1 is a partly sectional diagrammatic View showing the relative positions on the vehicle and with respect to the engine of the several parts of the fuel feeding system embodying the invention.

Figure 2 is a detail elevation on an enlarged scale of the parts of the system which are located on and adjacent to the engine body.

Figure 3 is a section at the line 33 on F igure 2.

Figure 4; is a section at the line 4-4 on Fig- 2 ure 1.

Figure 5 is a vertical fore-and-aft section through the main fuel supply tank shown in Figure 1 as carried at the rear of the vehicle, section being made at a plane cutting through the center of aprimary fuel mixture forming apparatus which is located in said main fuel tank.

Upon considering the drawings in a comprehensive manner it will be seen that there is mounted on the engine a construction of the nature of a mixing chamber having the air inlet controlled by an air valve which is normally seated by a spring and adapted to be 4.0 opened by engine suction.

This structure comprises a fuel mixture passage leading to the. engine intake, said structure being mounted on the intake manifold and arranged for connection with a .pri-

mary fuel mixture pipe discharging in the air stream flowing to the intake manifold when the air valve mentioned is opened by engine suction. This engine-supported part of the structure comprises also a dash pot hav- 5o ing a plunger connected by a lever with the Serial No. 309,942.

air valve for slowing down both the opening and closing movements of that valve.

It will vbe noted that the primary fuel mixture pipe leads to the engine for delivering primary fuel mixture into the air stream, as stated, from a'primary fuel-mixture-forming apparatus which is located in the main fuel tank at the rear of the vehicle, said fuel mixture forming apparatus comprising a governed level fuel chamber of the character of a common carbureter float bowl, which derives fuel by gravity flow from the main fuel tank within which said fuel chamber is located.

It will be further noted that the expedient by which this fuel mixture forming apparatus is positioned within the main fuel tank consists in providing a cylindrical casing which is intruded in the main fuel tank from above the same through an aperture provided for that purpose, said casing being closed at both bottom and top, the top closure member being outside the main fuel tank, and the lower end portion of said casing constituting the governed level fuel chamber, which derives fuel through a bottom opening by gravity. from the main tank. And it will be noted that the primary fuel mixture conduit consists of a pipe which leads into said casing through the top and extends down into proximity to the governed level of the governed level fuel chamber, and thence up to the top of the casing from which it emerges for extending forward to the engine.

And it will be noted also that for discharge of fuel into this primary fuel mixture pipe there are provided two ducts leading from the governed level chamber, one of which extends up through the top of the casing, and is reflexed for discharging downwardly into the downwardly leading limb of the pipe, which thereby becomes a fuel mixture pipe, the other of said ducts projecting for discharge of' fuel into said pipe at the lower end of the upwardly extending limb of said pri- 5 mary f-uel mixture pipe.

Referring to the drawings for describing the construction in detail :-The engine body is indicated at A, with the intake manifold at A The main fuel tank is shown at B at the rear of the vehicle. C represents the engine exhaust pipe, in which the muffler is shown at C A construction of the nature of a pipe fitting formed for mounting on the engine body for communication with the intake manifold is shown comprising apart, 20, hereinafter referred to as the final fuel mixture conduit, which is in Venturi form having its flaring entrance member, 20 bell-shaped, to form what is hereinafter referred to as a bell mouth, said fitting being extended from said bell mouth to form an air inlet chamber, 22, having an air valve, 24, held normally seated by a spring, 25, coiled around the stem, 26, of said valve, and reacting against a threaded sleeve, 27, which is screwed into the back or under side of the air chamber at a boss, 22 provided for that purpose, the stem of the valve being extended through the sleeve, and said sleeve being adjustable at its mounting in the boss for adjusting the tension of the spring to adapt the valve to begin to open at a predetermined degree of engine suction, and to open proportionately to the increase of suction bevond said predetermined degree. ldounted adjacent to the fitting in fixed position with respect thereto, there is provided a dash pot chamber, 28, having its plunger, 29, connected by a lever, 30, with the air valve stem, 26, so that the dash pot resistance operates to oppose and slow down the movement of the air valve either in opening or closing.

Within the bell mouth, 20, of the Venturi portion, 20, of the fitting, there is fixedly positioned a tapered approximately conical air discharge terminal, 21, which fits at its wider end tightly in the bell mouth entrance, its narrower end, which may be referred to as the air nozzle or jet end, standing concentrically in the venturi proximate to the constriction thereof annularly spaced from the inner wall of the venturi at that point.

The bell mouth form of the entrance end of the venturi, in conjunction with the conically tapered, and also as shown, slightly exteriorly concave-form of the air nozzle, 21, creates a cavity within said bell mouth and around the air nozzle, into which the primary fuel mixture is discharged by the primary fuel mixture pipe, 50, which is connected at one side of the bell mouth, as seen at 52.

Referring to the construction of the primary fuel mixture forming apparatus and main fuel tank, as shown in Figure 5, it will be noted that the pipe which becomes the primary fuel mixture pipe at its extent through the primary fuel mixture forming apparatus, has its inlet, as shown at 30, at a point forward of the muflier, C through which said pipe extends, as indicated in dotted line in Figure 1, continuing from the rear end of the muffler rearward past the under side of the main fuel tank, B, behind which said pipe extends upwardly, and thence forwardly for connection, as shown at 35, with the upper end cap, 41, of the tubular casing, 40, which, as above mentioned, isintruded down through the top of the fuel tank, B, where an opening furnished with a flanged collar, 40, is provided for admitting said casing and seating its cap, 41.

The bottom cap, 42, of the casing has an inlet port, 43, controlled by a valve, 44, whose stem extends up into the casing and is connected with afloat, 44", which governs the level to which the liquid entering by gravity from the main fuel tank into the casing can rise in the casing; whereby the casing at its lower part becomes a governed level fuel chamber. From the aperture in the cap, 41, at which the pipe, 30, is connected, as seen at 35 said aperture extending in angular form and opening downwardly from the cap, there is connected a pipe member, 32, constituting a down limb of the conduit of which the pipe, 30, is the initial part. Said pipe, 32, extends downwardly approximately to the governed liquid level above the float, 45, and is there flexed to extend horizontally above the float a short distance, and connected by an elbow fitting, 33, with an upwardly extending limit, 34, which extends in spiral form up through the casing, 40, and is connected at its upper end at an aperture, 36, through the cap plate, 41, and opening forwardly and horizontally for connection with a pipe member, 38, which constitutes a continuation of the primary fuel mixture conduit and leads forwardly to the structure above described mounted at the engine intake manifold, where said pipe is connected, as above pointed out, at the aperture, 52, for discharging into the air stream entering the engine past the air valve, 24, through the air chamber, 22.

Referring to Figure 5 there may be seen a fuel duct, 45, which leads from the lower part of the governed level fuel chamber in the bottom of the casing, 40, with horizontal deflection for entering the elbow fitting, 33, through which it extends liquid-tight, and within said elbow fitting is deflected upwardly for discharge upwardly in the up limb, 34, of the primary fuel mixture conduit. And there will be seen also leading similarly from the lower part of the governed level fuel chamber a pipe, 46, extending up in the easing, 40, and connected with a passage, 48, in the cap, 41, at the upper end of which there is provided a nozzle terminal, 49, creating a 180 bend which affords downward discharge into the upper end of the fuel mixture conduit pipe member, 32.

It will be noted that while the fuel discharge duct, 45, has its discharge directly in the lower entrance end of the up limb, 34, where said pipe is of full diameter, a different construction is provided at the discharge of the fuel duct, 46, where its return bend through the pipe, 38, to the engine.

nozzle discharges into the down limb, 32, there being formed at the entrance of said down limb a small venturi, 47, proximate to the constriction whereof, the return bend nozzle, 49, terminates for fuel discharge.

The purpose of the provision of two fuel ducts discharging in the air pipe for forming a primary fuel mixture is to adapt the construction to yield primary fuel mixture of suitably varying richness under varying conditions of engine operation. It may be understood that under engine operating conditions which developa high degree of suction at the entrance of the primary fuel.mixture pipe to the air stream, with which it is to blend to form the final fuel mixture which serves the engine, the depression at the discharge of the duct 45, in the up limb, 34, will be suiiicientto take the fuel from the duct, 45, and cause it to be suitably intermixed with the air as it passes through the spiral extent of said up limb, and thence on But that under such conditions of low engine suction, the depression in the pipe, 30, at the point'at which the fuel duct, 46, opens for discharge of fuel into the down limb, 32, in the absence of the venturi, 47,, will not be sufficient to lift the fuel from the governed level chamber through the height of the main fuel tank, 13, and cause the fuel to be discharged into said down limb, 32. And it may be understood'that upon increase of the suction, causing increase of the amount of fuel which will be taken through the duct, 45, such increase will continue in diminishing degree, as the suction continues to increase, a point being finally reached at which further increase of the suction does not ap. preciably increase the amount of fuel taken; and that at some stage in the increase of suction, the depression at the discharge of the pipe, 46, in the down limb, 32, will be sufficient to lift the fuel through the duct, 46, from the governed level chamber to said discharge point; and that the provision of the venturi, 47, at this point causes the delivery of fuel through the duct, 46, at a lower de- 50\gree of engine suction than would be the case in the absence of such a venturi. I have ascertained that the dimensions of the several parts affecting the flow capacity of the duct, 45, the flow capacity of the duct, 46', and the acceleration of the air flow by the venturi, 47 may be designed in accordance with demonstrated rules to cause the total flow of fuel through both ducts, 45, and 46, notwithstanding at part of the time fuel is flowing only through the duct, 45, and part of the time increasingly through the duct, and part -of the time gradually and increasingly through the duct, 32, to vary suitably in relation to the variation of engine suction under different running conditions, so as to cause the primary fuel mixture to be of proper for the primary fuelmixture derived through the pipe, 50, which is ample at the zone of the entrance to the pipe, 50, and diminishes in cross section toward the relatively small annular discharge. at the Venturi constriction,-

has been found of very material advantage in obtaining the desirable gradual change in the depression at that point instead of the relatively abrupt changes which are unavoidable when the form of the Venturi entrance and the air nozzle discharge thereinto are of the more common simple frusto-conical form.

The arrangement of the air valve, 24, and the dash pot, 29, relatively to each other for facilitating the employment of lever connection between the two, and the employment of such connection adapted to make the plunger movement a small fraction of the valve movement, 'as by making the lever arm connected to the plunger several times the length of the lever arm connected to the valve, has been found of very substantial advantage in causing the valve-opening movement to be correctly and reliably related to the engine suction, avoiding abrupt changes in the air supply which tend to prevent uniformity in the fuel mixture because the ertia of the liquid fuel, tends to prevent it responding to abrupt changes in the air flow which produces corresponding abrupt changes in the depression at the fuel nozzle.

The spiral form of the fuel mixture pipe, 34, while operating slightly for retardment of the flow, is chiefly important by reason of the spiral movement of the current through it i which this form compels, and which causes a centrifugal action of the liquid particles more or less completely atomized, causing their impact upon the walls of the pipe. which results in deposit of the liquid, which, flowing slowly down the spiral wall, is exposed to the air current rushing past it and operating to wipe it up, with the effect of more complete atomization, the delay in view of the circumstance that the air current has been pre -heated and that the walls of the spiral pipe are corresponding heated, causing vaporization of an important percentage of the liquid fuel which would otherwise be only atomized by the action of the air current.

I claim 1. In a direct fuel feed system for motor vehicles, an internal combustion engine having an air supply passage to the engine intake,

a main fuel supply tank mounted on the vehicle remotely from the engine and a primary-fuel-mixture-forming apparatus located proximate the tank and comprisin a governed level fuel chamber, a discharge uct therefrom and a pipe into which it discharges for forming a primary mixture, said pipe leading from its'intake rearwardly into proximity to the governed level fuel chamber for receiving fuel discharge from said chamber and having its course rearwardly from the inlet to the governed level fuel chamber extending through a portion of the engine exhaust passage along the exhaust pipe and through the muflier; whereby the air current through said pipe into which the fuel is discharged is heated for vaporizing said fuel at its discharge.

2. In a direct fuel feed system for motor vehicles, an internal combustion engine having an air supply passage to the engine intake, a main fuel suppply tank mounted on the Vehicle remotely from the vehicle, a primaryfuel mixture forming apparatus located proximate the tank and comprising a governed level fuel chamber, a discharge duct therefrom and a primary fuel mixture pipe into which it discharges, said primary fuel mixture pipe having its course from its inlet rearwardly to the governed level fuel chamber extending through the mufiier and having its return course from the governed level fuel chamber extending forwardly to the engine for discharge with the air entering the air supply passage of the engine intake, and having at a part of its said return course a. heating acket connected with the engine exhaust 3. In a direct fuel feed system for motor vehicles. an internal combustion engine having an air supply passage to the engine intake, a main fuel supply tank mounted on the vehicle remotely from the engine and a primary-fuel-mixtute-forming air passage located within the tank and. comprising a governed level fuel chamber, a discharge duct therefrom and a primary fuel mixture pipe into which it'discharges, said primary fuel mixture pipe having its course from its air inlet rearwardly to thegoverned level fuel chamber leading through the muflier and having its course from its emergence, from the main tank forwardly to the engine for discharge with the air entering the air supply passage to the engine intake and having at a part of its said-return course a heating jacket connected with the engine exhaust pipe.

. cated proximate-the fuel tank comprising a '4. Ina direct fuel feeding system for mogoverned level fuel chamber arranged to derive fuel by gravity from the tank, a primary air pipe having atmosphere intake at a point governed level fuel chamber having a fuel discharge duct extending for discharge in the upwardly extending limb of the primary air pipe for producing a primary fuel mixture; whereby said primary pipe conducts preheated air to the point at which fuel is discharged thereinto for producing said primary fuel mixture, and said mixture is rendered in part vaporous at its formation and at its discharge in the main air pipe.

5. In a fuel feeding system for motor vehicle internal combustion engines, in combination with a main fuel supply tank mounted on the vehicle relatively distant from the engine, a main air supply pipe leading to the engine intake; a primazy-fuel-mixture-forming apparatus consisting of a governed level fuel chamber, a primary fuel mixture conduit terminating for delivery of a primary fuel mixture in the air stream flowing toward the engine through the main air supply pipe, and fuel discharge ducts from the governed level chamber discharging into the primary fuel mixture conduit, one near the governed level of said chamber and another at a substantial distance above said level.

6. In the construction defined in claim 5, the primary fuel mixture conduit having a Venturi constriction at the location of the higher leveldischarge into said conduit.

7. In the construction defined in claim 5, the higher level discharge being antecedent in the course of the air flow through the conduit, to the lower level discharge.

8. In the construction defined in claim 5, the higher level discharge being antecedent in the course of air flow through the conduit, to the lower level discharge, the conduit being flexed in spiral form at the upwardly extending part following said lower level discharge.

9. In a fuel feeding system for motor vehicles in combination with a main fuel supply tank, a primary-fuel-mixture-forming apparatus consisting of a governed level fuel chamber arranged to derive fuel by gravity flow from. the tank, a discharge duct therefrom and a primary fuel mixture pipe into which said ,duct discharges for forming therein a primary fuel mixture, said pipe having a portion of'its extent flexed in spiral form for promotingtheagitation and thereby the intermixture of the air and fuel flowing through said pipe.

10. In the construction defined in claim 9, the spirally formed portion being an upwardly extending portion of said primary mixture onduit. 1

11. In a fuel supply system for internal combustion engines, a primary fuel mixtureforming device comprising in combination with a fuel chamber, a fuel discharge duct leading therefrom, a pipe within which the duct terminates for discharge and mixture of the fuel with the air current through said pipe, said air pipe having a substantial portion of its length extending spirally for causing centrifugal action of the liquid particles carried by the air current, causing them to impinge on the wall of the pipe.

12. In a fuel feeding system for internal combustion engines, in combination with the engine exhaust conduit and fuel supply tank, a primary-fuel-mixture-forming apparatus located proximate to the tank and comprising a governed level fuel chamber, a discharge duct therefrom and a primary fuel mixture pipe into which'it discharges, said primary fuel mixture pipe having its course from its inlet to the governed level fuel chamber extending through the exhaust muffler and having its return course from the governed level fuel chamber extending for discharge with the air entering the air supply passage of the engine intake, and having at a part of its said return course a heating jacket connected with the engine exhaust conduit.

13. In a fuel feeding system for internal combustion engines, in combination with the engine exhaust conduit and fuel supply tank, a primary-fuel-mixture forming air passage located Within the tank and comprising a governed level fuel chamber, a discharge duct therefrom and a primary fuel mixture pipe into which it discharges, said primary fuel mixture pipe having its course from its air inlet to the governed level fuel chamber leading through the exhaust muflier, and having its course from its emergence from the main tank trending toward the engine for discharge with the air entering the air supply passage to the engine intake, and having at a part in said return course a heating jacket connected with the engine exhaust conduit.

14. In a fuel feeding system for internal combustion engines, in combination with the engine exhaust conduit and main fuel supply tank, a primary-fuel-mixture-forming apparatus located proximate the tank and comprising a governed level fuel chamber arranged to derive fuel by gravity from the tank, a primary air pipe having atmosphere intake at a point remotely forward of the tank, said pipe extending along the exhaust conduit and through the exhaust mufller to the vicinit of the fuel tank, and proximate to the liquid level of said governed level fuel chamber, said pipe thence turning upwardly and leading forwardly to the engine for discharge in the main air supply passage of the engine; the governed level fuel chamber having a fuel dischargeduct extending for discharge in the upwardly extending limb. of said primary air pipe for producing a primary fuel mixture; whereby said primary pipe conducts pre-heated air from the point at which fuel is discharged thereinto for producing said primary fuel mixture, and said mixture is rendered in part vaporous at its formation and at its discharge in the main air pipe.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois, this 29th day of September, 1928.

WILLIAM A. EDWARDS.

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