US1812013A - Fuel feeding system for internal combustion engines - Google Patents

Description

June 30, 1931. w, zz 1,812,013

FUEL FEEDING SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed July 2. 1928 I 2 Sheets-Sheet 1 21 k j m 25 W W 7 jiadeniazi WZZZZamHU/W m I j I Am g grzzays- W. H. MUZZY June 30, 1931.

FUEL FEEDING SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed July 2, 1.928 2 Sheets-Sheet 2 m JM M Patented June 30, 1931 UNITED STATES PATENT OFFICE WILLIAM H. MUZZY, OF EVANSTON, ILLINOIS, ASSIGNOR TO STEWART-WARNER GOR- PORATION, OF CHICAGO, ILLINOIS, ACORPOBATION OF VIRGINIA FUEL FEEDING SYSTEM FOR INTERNAL COMBUSTIONIINGINES Application filed July 2, 1928. Serial No. 289,692.

The purpose of this invention is to fprovide improved means for lifting fuel rom a fuel source to a chamber from which it may be supplied to the carbureter of an internal combustion engine. It consists in the elements and features of construction shown and described as indicated in the claims.

It has heretofore been proposed to associate with a vacuum tank, provided as the primary means of pumping fuel from a fuel source for supplying the engine, and for that purpose connected for suction with the intake manifold of the engine, an additional means of producing vacuum in the vacuum chamber of thevacuum tank, an engine-operated piston pump havin its intake connected for exhausting air om the vacuum chamber. And it has also been proposed to employ such air pump as the sole means of producing the desired vacuum in the vacuum chamber. A serious objection to the employment of such piston pumpeither as an auxiliary or as the sole or princi al means for the purpose, is the difficulty 0 lubricating at the high speed at which the pump must operate if arranged to be driven directly by an engine shaft; and if speed-reducing connections are interposed, the complication and cost and short life of the speed-reducing train constitute an equally serious objection.

In the present construction these objections which pertain to a piston pump are avoided by employing a flexible diaphragm pump, and avoidin the objection to that type consisting in t e liability of the diaphragm to become cracked or otherwise ruptured from the rapid vibration to which it is subjected when arranged to be vibrated by direct connection with an engine shaft, by means of expedients which will be hereinafter more fully explained, andjparticularly by connecting such pump with the intake manifold of the engine from which the suction is primarily derived for vacuum in the vacuum tank vacuum chamber, and making the connections such that the diaphragm pump comes into service only to the extent necessary to supplement the intake manifold suction. But 1t is necessary to take into phragm pump to harmonize with these requirements of thevacuum tank, constitutes an important feature of this invention.

In the drawings: Figure 1 is a partially diagrammatic elevation showing the structure embodying this invention in the relation of the same to the engine and the vacuum tank with which the invention co-operates.

Figure 2 is a section at the line 22 on Figure 1 on an enlarged scale, being an axial section of a diaphragm pumping device which constitutes an essential feature of the invention.

Figure 3 is a detail elevation of a threeway valve and the connections.

Figures 4, 5 and 6 are sectional views of the same showing the valve at three different positions.

Figure 7 is a view similar to Figure 2 showing a different form of pump in which the pumping member is positively actuated in both directions.

For avoiding action of the diaphragm, except when and to the extent necessary to supplement the direct action of the engine intake manifold vacuum, which avoidance is a characteristic feature of the preferred form of the invention, the diaphragm is arranged to be spring-actuated for its intake or suction stroke and free from engine actuation in the direction of that stroke, being engine actuated only in the discharge or return stroke, and therefore exposed to the positive actuation of the engine only to the extent that the conditions permit the spring to react for the intake or suction stroke.

A diaphragm pump with its inlet and discharge connected respectively to the vacuum chamber of the vacuum tank, and for discharge to the atmosphere, would constitute a working structure for pumping the fuel from a low level source to the tank from which it maybe supplied by gravity to the carbureter of the engine; but it has been discovered that under conditions of low temperature, the operation of the diaphragm which is of flexible fabric, is greatly retarded or stopped; and the fabric is also subject to leaks and ruptures from continued use. And when a break occurs, the driver of the car Whose engine is served by the device, is in-serious trouble because the engine cannot be supplied with fuel. For this and other reasons the present invention comprises a flexible fabric diaphragm pump as a supplement to the usual connection of the vacuum tank vacuum chamber to the intake manifold of the engine for developing vacuum in said vacuum chamber, the diaphragm pump constituting, however, a permanent part of the fuel feeding system.

In both embodiments of the invention shown, a pipe from the intake manifold of the engine is connected to the discharge port of the diaphragm pump, and the intake of the diaphragm pump is connected by a pipe with the vacuum chamber of the vacuum tank, and thus the two sources of suction, viz, the engine intake manifold and the pump, are connected in series for developing vacuum in the vacuum chamber of the vacuum tank. One result of this order of connection 'is that the vacuum produced by the pump is added to or boosted by that of the manifold, and at the same time the natural action of the pump is assisted, because the'air is drawn in more quickly through the intake and discharged more quickly from the discharge port than it would be by the action of the pump alone. The resulting vacuum in the pipe line leading to the vacuum chamber of the tank is always higher than that which would be derived from the manifold alone.

A second result is that the air discharged from the discharge port of the pump to the engine intake manifold is heavily laden with gas drawn from the vacuum chamber of the vacuum tank; and this gas being discharged into the engine manifold, is fed into and used in the engine.

During the normal operation of a system including a diaphragm pump of the type shown in Figure 2, viz., having the dia phragm spring-actuated in the direction for intake or suction, at normal engine speed the vacuum which is produced and maintained in the engine intake equals orcxceeds the vacuum which the reaction of the diaphragm-retracting spring is capable of producing in the pump chamber by the retraction of the diaphragm in its suction or fuel lifting stroke; and in consequence, at 1 that stage of engine suction the diaphragm is held at the limit of its feeding stroke,

causing the spring which is provided for retracting it to be as fully compressed as it can be by the engine cam at the climax of the active phase of the cam cycle; and so long as the engine suction is of this degree, the diaphragm remains at the limit of its feeding stroke holding the spring compressed and the diaphragm stem or other operating connection retracted from the cam shaft to the limit' of the sweep of the cam, which accordingly rotates idly so far as any actuation of the diaphragm is concerned; and the intake and discharge valves of the pump both opening the direction for fluid movement through the pump chamber, the pump chamber becomes a mere path for the transmission of the vacuum .from the engine intake manifold to the vacuum chamber of the tank.

If, however, with this type of pump the vacuum in the intake manifold at any time falls below the degree suflicient to condition the spring for reaction on the diaphragm, said spring will immediately react and give the diaphragm its suction stroke for produc ing vacuum in the vacuum chamber of the vacuum tank; and thus the vibratory action of the diaphragm will continue to some extent as long as the vacuum in the intake manifold is less than sufficient to hold the spring thus fully conditioned for said reaction.

If the manifold vacuum thus remains low or continues to decline, as it does at high engine speed, the pump takes up the work automatically as the manifold vacuum fails.

If the manifold vacuum should entirely disappear, the pump diaphragm will be found making its full stroke and the diaphragm pump will be substantially doing the full work of providing the necessary degree of vacuum in the vacuum chamber of the vacuum tank. As the manifold vacuum rises, the pump gradually reduces its operation, the diaphragm being held flexed in the direction for holding the spring compressed wholly or partly, so that the diaphragm is actuated by the engine, only for a portion of its normal stroke in each rotation of the engine shaft.

The diaphragm of the pump is thus called into operation only at certain periods, and for this reason the flexible fabric of which it is composed has greatly extended life fuel from the fuel source, which may be understood to be the usual low level tank at the rear of the car, not shown. 3 is a pipe which constitutes the suction connection to the vacuum chamber of the vacuum tank, said pipe leading from the inlet port, 12, of the diaphragm pump shown in Figure 2; 4 is the pipe by which the fuel is delivered from the reserve chamber of the vacuum tank to the carburetor shown at 5.

6 represents the intake manifold of the engine; 7 and 8 are members of the pipe leading to the intake manifold from the discharge, 9, of the diaphragm pump. 10 is a three-way valve interposed between the pipe members, 7 and 8, having for the purpose hereinafter explained, one way con nected by a pipe, 11, hereinafter referred to as the pump by-pass pipe, with a pipe, 3, with which it makes connection .by a T-fltting, 11*, a check valve fitting, 11 being interposed in the by-pass pipe, 11, for the hereinafter explained purpose.

Referring to Figure 2 in detail, the diaphragm pump chamber comprises the two members, 20 and 21, which are clamped together by bolts, 33, clamping between their marginal flanges the flexible diaphragm, 19, which has its central area clamped between two disks, 41, which are thus clamped to the diaphragm by a nut on the end of the diaphragm stem, 22, which extends throu h a guide bearing boss, 20 which projects rom the casing member, 20. Said casing member has a cylindrical extension, 26, terminating in a flange, 23, by which the pump casing is mounted upon the engine casing indicated at 50, having an aperture, 51, registering with the cavity of the cylindrical boss, 26, which is provided for housing the diaphragm-actuating spring, 24, having a cap, 29, at its outer end through which the headed stem, 22, of the diaphragm is inserted for entering the guide bearing, 20, and being connected with the diaphragm as mentioned above.

The head, 28, of the diaphragm stem, 22, serves for co-operating with the eccentric cam, 18, carried by an engine shaft, 17, within the engine casing. A. purpose of the considerably extended hollow cylindrical boss, 26, with its flange, 23, as mentioned, is to space the pump chamber, 2021, away from the engine body so as to avoid danger of overheating the diaphragm from the heat of the engine. The pump casing member, 21, has at its outer side, bosses in which respectively the inlet passage, 38, and the discharge passage, 34, are formed, terminating respectively in nipples, '12 and 9, for connection with pipes, 3 and 8, respectively, above mentioned, leading respectively to the vacuum chamber of the vacuum tank and to the intake manifold; and the same bosses accommodate respectively the inlet controlling valve, 37, and discharge controlling valve, 30, both opening for flow through the pumping chamber, 40, which is the chamber at the outer side of the diaphragm, 19, said valves being normally seated by springs, 36 and131, respectively, which are retained by plugs, 35 and 32, respectively.

One of the peculiar and important results of using the pump chamber as a passageway for the vacuum from the manifold to the vacuum chamber of the fuel pumping device is that the presence of the manifold vacuum in the pump chamber pulls all the parts connected to the diaphragm up tightand holds them so and prevents all vibration and rattling of the actuating means for the diaphragm.

Further, as the gas-laden air from the vacuum tank passes over the diaphragm, it moistens the same with gasoline and thus prevents it drying outand cracking.

Again the connection of the manifold to the discharge of the pump assists in opening the pump valves even though a very slight vacuum may be present and the pump may be working to supply an additional needed vacuum. The operation of the pump is thus assisted rather than retarded as it would be if the connection from the manifold were made with the inlet valve of the pump. If the connection were made in this manner the dominating vacuum from the manifold would tend to hold the inlet valve shut and would thus put the pump under additional stress.

If any part of the pump mechanism, such as the spring or the operating stem, were to break, the system would continue tooperate on the manifold vacuum through all the speed ranges up to about miles per hour or on hills up to the point where the throttle of the engine were almost entirely open. This is true of all accidental breakage except the diaphragm.

Should the diaphragm break, the operator adjusts the three-way cook, 13, from the position shown in Figure 4, in which pipes,

7 and 8, are in connection, by giving it a quarter turn to bring the pipes, 7 and 11, into connection and closing the pipe, 8, as seen in Figure 5. This adjustment puts the manifold directly into connection with the vacuum tank, by-passing the pump, and the engine will continue to be supplied with fuel without the aid of the pump until repairs can be made on the pump. In this adjustment, although the pump is'by-passed, as mentioned, the vacuum from the manifold has access by the pipe, 3, to the valve, 37, of the pump, and operates to hold that valve seated so that no air may leak from the punctured diaphragm to decrease the vacuum derived from the manifold.

The splash of oil from the crank case of the machine covers the stem, 22, and lubricates it. The part, 20*, is further provided.

with an aperture or oil well, 25, in which part of the splash accumulates and thus fully oils the stem at all times.

It will be understood that while I have described the preferred form of air pump as being of the diaphragm type, for the reasons stated, it will also be possible to use other forms of pumps, and I do not care to limit myself to the diaphragm type in the peculiar manner of connecting the pump, the manifold and the vacuum tank, which means the pump is practically floated on the line between the manifold and the vacuum tank. Any pump having an intake and discharge may be so connected and secure part of the advantages, at least of the presence of the manifold vacuum in the pump chamber. For instance, the connection in series enables the manifold, pump and vacuum tank to be connected for conjoint operation, and to automatically pass from manifold to pump operation without the presence of a. check valve in the line, such as is necessary when the manifold and the pump are connected to the vacuum tank in parallel instead of in series.

If connected in parallel, then the failure of the manifold vacuum would also cause the failure of the pump vacuum unless a check valve were placed in the manifold pipe connection so that it would close the manifold connection under those conditions and thus allow the pump vacuum to become effective in the vacuum tank.

It will be recognized that instead of making the connection of the two sources of suction to the vacuum tank in series, i. e., so that the manifold vacuum shall be communicated to the vacuum chamber through the pump,-the two sources may be connected in parallel by adjusting the threeway valve, as shown in Figure 6. But it will be evident that with this connection in parallel when the manifold vacuum falls below that developed by the pump, the pump would tend to draw gases from the manifold; and to prevent this is the purpose of the check valve, 11", interposed in the bypass pipe, 11, as mentioned.

A reason for making provision for connecting the two suction sources with the vacuum tank vacuum chamber in parallel, is, that when the connection is in series, it has been found that notwithstanding the tendencyof the high manifold vacuum to hold the pump diaphragm out of action so that the pump ceases for the time being to be a vacuum-producing element, the vacuum in the pipe, 3, anterior to any restriction which may be interposed between the vacuum pump and the vacuum chamber of the vacuum tank under some circumstances approximates'the sum of the manifold vacuum and the pump vacuum, and may even exceed the maximum intake manifold vacuum; and except as prevented by the restriction commonly interposed in the connection before or at the entrance to the vacuum chamber, and the relative freedom of inflow of the liquid lifted by the suction from the lower level to the vacuum chamber, the vacuum resulting in the vacuum chamher is liable to exceed the buoyant capacity of the float for breaking the suction hold on the atmosphere valve.

For this reason in some cases, as in case the suction connection to the vacuum tank for any reason is provided with a restriction which permits exceptionally free air flow to the manifold, or in case the liquid flow from the low level fuel source is embarrassed so that the flow responds sluggishly to the suction, it may be found desirable to avoid the accumulation of manifold suction upon pump suction, as results from the connection in series, by making the connection in parallel; and this is accordingly effected by adjusting the three-way valve as seen in Figure 6, so that the air flows from the pump directly through the horizontal passage of the threeway valve at the same time that it flows through the by-pass pipe, 11, and the vertical passage of the three-way valve.

It will be recognized that if the dia-- phragm pump is actuated positively in both directions so that there is afforded no opportunity for the manifold vacuum to hold the diaphragm out of pumping action, the liability to building up excessively high vacuum in the pipe connection from the intake manifold to the vacuum tank and under certain circumstances as mentioned above, causing in the vacuum chamber such high vacuum as to defeat the ca acity of the float for breaking the suction old upon the atmosphere valve, will become a practical certainty; and accordingly when such a pump is employed, it would be most desirable to employ the connection in parallel, rather than the connection in series.

The construction of the pump having'the diaphragm positively actuated in both directions may be understood from Figure 7 without further specific description beyond pointing out that the spring for retracting the diaphragm for its suction stroke is omitted, and the diaphragm stem, 22, is engaged with the cam, 18, for positive actuation in both directions as the shaft, 17, is rotated by the engine.

I claim:

1. In combination with an internal combustion engine, a fuel feeding system comprising a vacuum pumping device having a vacuum chamber, an engine-driven pump having intake and discharge check valves, a conduit connecting the intake of the enginedriven pump with the vacuum chamber of the vacuum pumping device, a conduit connecting the discharge of the pump with the intake manifold of the en ine, whereby communication is provided mm the vacuum chamber of the vacuum pumping device through the engine-driven pump to the intake manifold of the engine, and a by-pass ipe connecting the first mentioned condult between the intake check valve and the m vacuum chamber of the vacuum pumping device with the second mentioned conduit between the discharge check valve and the manifold, and a check valve in said by-pass opening for fluid flow toward the second mentioned conduit.

2. In combination with an internal combustion engine, a fuel feeding system comprising a vacuum pumping device having a vacuum chamber, an engine driven pump, a

go conduit connecting the intake of the enginedriven pump with the vacuum chamber of the vacuum pumping device, a conduit connecting the discharge of the pump with the intake manifold of the engine, whereby communication is provided from the vacuum chamber of the vacuum pumping device through the engine-driven pump to the intake manifold of the engine,a by-pass connecting the first mentioned conduit with the second mentioned conduit, a check valve in said by-pass opening for fluid flow toward the second mentioned conduit, and a three- ,way valve at the junction of the by-pass pipe with said second mentioned conduit 88 adapted to be adjusted for flow only from the pump discharge to the intake manifold, or for flow both from the by-pass pipe and from the pump discharge towardthe intake manifold, or for flow only from the by-pass a pipe to the intake manifold.

'3. In combination with an internal combustion engine, a fuel feeding system com prising a vacuum pumping device, an air pump connected for operation by the engine and having inlet and discharge valves, a

pipe connecting the intake manifold of the engine with the discharge'port of the pump, a pipe connecting the intake of the pump with the vacuum pumping device, and means for connecting the two pipes and cutting out the pump at will. p

4. In a fuel feeding system for an internal combustion engine in combination with. an

co'nnectedthereto respectively antecedent to y the intake valve and subsequent to the discharge valve, the intake conduit being extended and connected to the vacuum chamber of the vacuum tank and the discharge conduit being extended to the intake manifold,'and a conduit member connecting said intake conduit between the intake check valve and the vacuum chamber of the vacuum tank with the discharge conduit between the discharge check valve and the intake manifold, and a check valve in said conduit member opening for flow toward the discharge conduit.

In testimony whereof, I have hereunto set 111 hand at Chicago, Illinois, this 15th day 0 June, 1928.

- WILLIAM H. MUZZY.

engine intake manifold a vacuum tank and a conduit therefrom to the intake manifold,

a. pumping device comprising a pumping chamber having separate from each other an intake passage and a discharge passage with check valves controlling said passages for inflow and discharge, and seating against reverse flow; conduits from said passages connected thereto respectively antecedent to the intake valve and subsequent to the discharge valve, said conduits being connected 6 to the first mentioned conduit at points

Images