US2083021A

US2083021A - Fuel feeding system

Info

Publication number: US2083021A
Application number: US704933A
Authority: US
Inventors: Carl F High
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-01-02
Filing date: 1934-01-02
Publication date: 1937-06-08
Anticipated expiration: 1954-06-08

Description

June 1937. c. F. HIGH 2,083,021

FUEL FEEDING SYSTEM Filed Jan. 2, 1934 4 Shee'ts-Sheet 1 W g A w /3\ 5 73 72 /7 June 8, 1937.

C. F. HIGH FUEL FEEDING SYSTEM 4 Sheets-Sheet 2.

Filed Jar 2, 1954 I June 8, 1937. CF. HIGH FUEL FEEDING SYSTEM Filed Jan. 2, 1954 4 Sheets-Sheet 4 Patented June 8, 1937 UNITED STATES PATENT OFFICE,

'1 Claims.

This invention relates generally to fuel feeding systems for automotive engines and more particularly to improved means for supplying fuel to a fuel injection pump.

In fuel feeding systems and more particularly those wherein a pump is utilized for injecting fuel into an engine manifold or cylinders, it is highly desirable to prevent the formation of gas in that portion of the system which supplies the fuel to the pump. By gas it is meant the bubbles o'f flashed fuel which are generated principally by heat and vacuum, although it may mean any occluded gases. When ordinary gasoline is heated, the more volatile fractions are first flashed into gas bubbles and the remainder of the fuel flashes progressively as the temperature is raised. By imposing on this gasoline even a partial vacuum, as occurs when lifting fuel from a fuel tank, the flashing occurs at a decreased temperature. Any occluded gases are also subject to flashing under these conditions. The flashed fuel floats as bubbles suspended in the body of the fuel. However, as the gaseous bubbles are lighter than the liquid gasoline, they have a tendency to rise to the surface of the liquid, where they add themselves to the gaseous space which under other conditions has sometimes been known as vapor look.

When floating bubbles are inducted into a pump they replace the liquid fuel which should have been inducted on that cycle. This results in a decreased amount of fuel being delivered by the pump for that cycle, and the amount of fuel will likely be so decreased that the charge for that cycle will be so lean that it will fail to ignite. This causes the engine to miss, and if the pump can inhale only gas, as occurs in extreme cases. the engine will stop running due to the vapor lock). In anyv event the gas bubbles must be kept from the induction side of the pump to insure smooth and efiicient operation. It is the general object of this invention to provide new and'improved means for preventing the entry of gas to the cylinders of a solid fuel injection pump.

The solution of this problem can be divided into three parts. The first part consists in preventing, as far as possible, the flashing of the fuel. The second part consists in providing logical paths for the bubbles of flashed fuel to rise to a gas collecting dome without coming into proximity with the pump inlet or inlets. The third part consists in venting the gas which accumulates in the gas dome into the vacuum of the intake manifold or into any vacuum pump. Un-

der the third part would also occur the venting of the entrapped air in the fuel line and in the fuel chamber, for example, when first starting an engine after it has stalled because of an empty fuel tank. Accordingly other objects of the in-, vention include the provision of improved means for preventing flashing of the fuel, the provision of means affording suitable paths for the bubbles of flashed fuel, so as to divert and collect the gas without letting it come into proximity with the pump inlets, and the provision of means for venting the gas and air which is collected and accumulates.

In the form of the invention chosen for purposes of disclosure the foregoing and other objects are attained in the novel construction of the, casing forming the upper portion of a multiple piston pump. Flashing of the fuel is prevented or mitigated by maintaining the fuel as cool as possible, and primarily by coringout the pump casing so that air can circulate freely below the fuel chamber for cooling purposes. By limiting to the extreme the metal between the oil heated drive compartment of the pump and the fuel reservoir, an effective choke is provided to the conduction of heat through this metal.

It is a further object to provide an improved pump casing having a fuel chamber in the upper portion thereof and constructed so that air may be circulatedfreely below and around the fuel chamber so as to cool the chamber, together with connections between the pump head or upper portion of the casing in which the fuel chamber is formed, and the lowerportion of the pump casing containing the pump operating mechanism and heated oil, which are of limited sec Other objects will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in

which: i

Fig. 1 is a longitudinal sectional view approximately along the line l-l of Fig. 6.

Fig. 1a is a detail view of a pump piston. Fig. 2 is a fragmentary elevational view. Fig. 3 is a section along the line 3-3 of Figs.

1 and 2.

Fig. 4 is a section along the line 6-4 of Figs. 1 and 5.

Fig. 5 is a section along the line 5--5 of Fig. 6.

Fig. 6 is a section along the line 6-8 of Fig. 5.

5 Fig. 7 is a section along the line 1-1 of Fig. 5.

Fig. 8 is a section along the line 8-8 of Fig. 5.

For purposes of disclosure I have illustrated in the drawings and shall hereinafter describe in detail a preferred embodiment of the invention,

10 with the understanding that I do not intend to limit the invention to the particular construction and arrangement shown, it being contemplated that various changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

Inthe form illustrated in the drawings, the invention is embodied in a multiple cylinder fuel injection pump, and more particularly in the upper portion of the casing of the pump. The pumping mechanism may be of any desired or preferred form, the pump illustrated comprising a casing having a body portion or member ID, a bottom member ii and a top portion or head I 2, the member ii and head i2 being secured to the body member ill by means of screw devices ii' and i2 respectively. The body member has a plurality of circumferentially spaced vertically extending cylinders l3 formed therein in which 3 pistons l4 are arranged to be reciprocated by means of a cam l5 secured to the upper end of a vertically extending drive shaft IS. The cam l5 has a face cam surface I! which acts through connecting members l8 to reciprocate the pistons and is also provided with a cam slot i9 which functions during the reciprocatory movement of the pistons to oscillate the pistons through an angle of approximately 90 about their axes for the purpose of opening and closing the inlet port to the cylinders. As shown in Fig. 1, each cyl- 0 inder is provided with an inlet port 22 connected at one end with the cylinder at a point below the upper end thereof, and connected at the other end with the lower portion of the fuel chamber by a common metering orifice 23. Recesses 24 extending longitudinally in the periphery of the pistons adjacent the closed end of the cylinders are moved into alinement with the supply ports 22 during the intake strokes of the pistons, as shown in the left-hand portion of Fig. 1, the pistons being rotated approximately 90 to the position shown in the right-hand portion of Fig. 1 during the compression stroke. Individual exhaust or discharge ports 25 are pro- 55 vided for the cylinders as illustrated most clearly in Fig. 3. As shown in the drawings the cylinders i3 are bored entirely through the casing member ID to facilitate manufacture, the upper ends of the bores being filled by means of plugs 60 2B. 'I'he'fiow of fuel through the orifice 23 is governed by means of an adjustable metering valve 23'.

The upper portion of the body member IQ of the casing is provided with an annular recess 65 which coacts with a cavity 3i in the member l2 to form a closed fuel reservoir or chamber 32 in the head of the pump adjacent the upper ends of the cylinders. Fuel is adapted to be supplied to the chamber 32 through an intake port 33 7 (Figs. 4, 5 and 8) which may be suitably connected to the usual gasoline tank (not shown), below the fuel level in the tank, by means of a conduit 33'. Normally the fuel is inducted by means of the suction of the pump pistons. As illustrated 75 in the drawings, the fuel chamber 32, under certain conditions, may be subjected to suction produced by external means. Thus as shown most clearly in Figs. 1 and 4, a port 34 in the upper portion of the member I2 is adapted for connection to a suitable suction producing means, 5 such as the intake manifold of an engine, by means of a conduit 34'. A bushing 35 screw threaded in the member i2 forms a valve seat at its lower end for a valve 35', and also forms a valve seat at its upper-end, for a ball check valve 10 35". The valve 35' is operable by means of a float 36 carried on the free end of an arm 31, whicharm is pivoted on a horizontally extending pin 38, the lowerend of the valve 35' resting on the arm 31. In order to prevent as far as posl5 sible the flashing of fuel, it is desirable to position the fuel line from the gasoline tank to the pump so as to be as far as possible away from the heat generated by the engine and pumping mechanism. Preferably .therefore the conduit 0 33' is connected to the upper portion of the member l2 at a point which is farthest from the source of heat so as to reduce the heating of the fuel in the conduit. In addition to this, the invention provides means for cooling the portion of the pump casing or head which forms the fuel reservoir. This is accomplished in the present form of the invention by coring out the upper portion of the casing at 40 so that air can circulate freely below the fuel chamber 32. 30 The casing part ill is herein shown as having a plurality of tubular portions I0 forming the cylinders i 3, openings 4i being provided intermediate the tubular portions so as to connect with the central opening 40 beneath the fuel chamber. A further cooling advantage is obtained by limiting to the extreme the metal in the tubular portions ill so as to form a choke to the conduction of heat between the lower portion of the part ID which houses the pumping mechanism and the upper portion which forms the bottom of the fuel chamber. The openings in the casing beneath the fuel chamber for the purpose of circulating air therethrough to cool the adjacent parts, together with the heat choke formed between the lower portion of the casing and the fuel chamber, are operative to keep the fuel in the chamber cool so as to minimize flashing.

In order to insure the feeding of fuel in liquid form into the metering orifice 23, the invention not only provides means for keepingthe fuel cool in the chamber 32, but also means for preventing any bubbles of flashed fuel in the fuel chamber from reaching the orifice 23 and means for removing from the fuel chamber accumulated gas and any entrained air. In the present form of the invention, bubbles of'flashed fuel in the fuel chamber are prevented from reaching the orifice 60 23 by providing logical paths for the bubbles to reach the upper portion of the chamber or gas dome 42 rather than the metering orifice. To eliminate as far as possible bubbles which might be carried in by the incoming fuel through the 65 port 33 the incoming fuel is discharged into the fuel chamber in a horizontal direction so that any bubbles carried in the fuel are projected along the surface of the fuel rather than into it. Thus, as illustrated in Figs. 5 and 8, the incoming 70 fuel passes downwardly through a port 45 in a bushing 46 and then outwardly in a horizontal direction through a diametrically extending port 47 in the bushing, the horizontally extending port 41 being approximately in a plane with the normal fuel level in the fuel chamber 32, indicated in Figs. 1 and 5. Thus any bubbles in the incoming fuel are discharged directly into the gas dome above the fuel level.

The invention also contemplates the provision of means intermediate the inlet and the orifice 23 for preventing any gas bubbles in the incoming fuel from reaching the metering orifice. As illustrated herein, this means is in the form of a screen 50 (Figs. 1,5 and 6) which extends across the fuel chamber 32 intermediate the fuel inlet and the metering orifice. This screen is suitably secured along its bottom and side edges to the bottom and side walls of the fuel chamber, and along its upper edge is provided with a notch through which the float lever 31 extends. Gas bubbles will not readily passthrough a screen, and as the screen forms a vertical wall the bub bles on the fuel inlet side rise rather than pass through to the orifice side. In this way the screen serves as a bubble diverting or straining means. It also serves as a bafile to prevent the washing of bubbles from the movement of the vehicle in which the pump is mounted. As will be apparent from the drawings, and particularly Figs. 1 and 6, the float 36 is herein shown positioned on the orifice side of the screen so that if the screen becomes clogged with foreign matter, or due to the surface tension of the fuel, fuel will discharge over the top of the screen through the notch 5| and avoid stopping the delivery of the pump. By locating the float on the orifice or outlet side of the screen and the fuel inlet on the opposite side, if the screen becomes clogged, thefloat will drop and open valve 35 and cause fuel to rush in through the fuel inlet, the incoming fuel overflowing to the float side of the screen through the notch 5|. When sufficient fuel has reached the float side of the fuel chamber to raise the float, the external suction is cut off by the closing of valve 35'.

At times when the temperature of the entire mass of fuel in the fuel chamber is raised above the boiling point of the fuel, gas bubbles will be generated along the walls of the reservoir and throughout the body of the fuel. In order to prevent such gas bubbles from reaching the metering orifice 23, the invention provides short chamber so as to be continuously submerged in the fuel, and so that the gas bubbles will rise to the surface rather than be drawn downwardly into the orifice; If desired additional bafiles or screens may be provided surrounding the orifice in order further to prevent gas bubbles from entering therein As mentioned hereinbefore, the invention also embodies means for venting the gas bubbles which have accumulated in the upper part of the fuel chamber. In the: present form of the invention the period of venting is regulated by the float 36 operating through the lever arm 31 and the float controlled valve 35'. The exhaust port 34, as mentioned hereinbefore, is preferably connected by the conduit 34 to the intake manifold of an engine or a suitable vacuum pump. Thus when the gas accumulation in the upper portion of the fuel chamber reaches a predetermined amount, the float is depressed and the valve 35' is opened so that the manifold vacuum, operating through the conduit 34 exhausts the gas in the upper portion of the fuel chamber and creates a depression in the upper portion of the chamber, thereby causing additional fuel from the fuel supply tank to discharge into the chamber. As the fuel fills the chamber it raises the float and closes the valve 35, thus cutting off further communication with the intake manifold.

During normal operation the pump suction lifts the necessary fuel, although the float and manifold vacuum are ever present to vent out an accumulation of gas and to replace it with liquid fuel from the tank. The only time the normal operation is changed is when the engine is operating on a wide open airthrottle, for under such condition the intake manifold is operated at full atmospheric pressure. When under this condition the float drops to vent off an accumulation of gas, the pump would inhale air from the manifold and the column of fuel being lifted from the fuel tank would drop back. To provide for this contingency, however, the check valve 35" is preferably provided so as to prevent a reverse flow of air. As soon as the air throttle is partially closed so that a manifold depression is present, the normal venting procedure is re-established.

Were an engine to operate extensively on wide open throttle or on supercharge, a separate vacuum pump would be necessary to provide the vacuum for venting. In this instance, however, the vented gas is preferably returned to the fuel tank in order not to lose it.

In the preferred form of the invention, means is also provided for collecting any fuel which might leak downwardly along the pistons Hi from the upper ends of the cylinders. As illustrated in the drawings, the pistons are provided with annular peripheral grooves 60 intermediate their ends, which grooves communicate with longitudinally extending ducts 6| in the. surface of the pistons. The grooves 60 serve to collect the fuel, both liquid and gaseous, which leaks along the piston. In case the leakage is in the form of gas bubbles, it is preferably vented to the upper portion of the fuel chamber 32. Thus as illustrated most clearly in Figs. 5 and 7, a port 62 is provided in the casing part ill for each cylinder l3, each port 62 having its lower end located so as to communicate with the duct 6| during the compression stroke of the piston, the upper end of each port being preferably connected by means of a. vertical tube 63 to the gas dome 82 of the fuel chamber. Thusany fuel passing back through the return tube 63 is discharged irito the upper portion of the fuel chamber so that any bubbles in the fuel will discharge directly into the gas dome without admixture with the liquid fuel in the chamber.

In the pump illustrated in the drawings the pistons 13 are arranged to be moved downwardly by means of coiled springs 10 positioned intermediate the lower enlarged portions ll of the pistons and an opposed inner wall of the casing II). An adjustable stop plate 12 is preferably provided for limiting the downward movement of the pistons, the stop plate being adjustable vertically by means of nuts I3 and 14 threaded on a supporting post 15. The pistons are moved through their compression strokes by means of cam surface I! referred to hereinbefore. Down wardly projecting pins 'H' on the pistons extend through suitable openings in the plate 12 and the flanges on the members l8 and into engagement with the cam slot I 8, the cam slot being shaped so as to oscillate the pistons through an angle of approximately 90 as mentioned hereinbefore.

The orifice 23 preferably tapers downwardly as illustrated in Figs. 1 and 5 so that by adjusting the metering valve 23' vertically the flow of fuel through the orifice may be controlled. The

metering valve is herein carried on the lower end of a vertically movable pin 16 supported in the upper portion of the casing member I2. An annular cam member 11 is carried on the pin 16 and engages a roller 18 mounted on the casing member l2 so that by rotating the pin 16 by means of an arm IS the metering valve 23' moves vertically in accordance with the contour of the cam 11. To prevent jamming the metering valve 23 is slidably mounted on the pin 16 and is urged into its extended position by means of a coiled spring 80. The pin 16, together with the valve and the cam carried thereby, is urged upwardly by a coiled spring 8|.

In order to insure the operation of the valve by the float lever 31, the valve 35 has a head 82 at the lower end of its stem 83, the head 82 engaging the-lever 31 and being positioned intermediate the upper surface of the lever and a pair of prongs 84 (Figs. 1 and 6), bent upwardly from the lever.

An inlet 86 may be provided in the lower portion of the casing II] for connection by means of a suitable conduit to the engine oil supply, thus keeping the operating mechanism of the pump properly lubricated.

It will be readily apparent that the invention provides, first, effective means for preventing as much as possible the formation of gas bubbles in the fuel, second, logical paths for the gas bubbles, that may form, to reach the. surface of the liquid fuel without being inducted into the pump, and third, means for venting the accumulation of the gas to the intake manifold. The venting means is also effective to' vent air from the fuel line which may be present when the engine is first started, after having stopped running because of an empty fuel tank, or which might enter through small leaks in the fuel line or fuel chamber, thereby preventing an accumulation of such air which might eventually cause trouble or completely stop the engine if the air replaced the fuel.

The fuel chamber 32 is totally enclosed so that when connected in serial relation with the fuel conduit 33', the orifice 23 and ports 22 it forms a portion ofv an airtight conduit connecting the fuel supply tank with the pump cylinders. Thus during normal operation of the pump fuel is drawn into the fuel chamber by the suction of the pump pistons and the amount of fuel supplied to the cylinders is governed by means of the metering valve 23'.

I claim as my invention:

1. A liquid fuel pump for internal combustion engines having, in combination, a casing having a plurality of vertically positioned circumferentially spaced cylinders, a fuel chamber therein adjacent the upper ends of said cylinders, and external ventilating openings intermediate the cylinders and under the fuel chamber, pistons in said cylinders, operating mechanism for said pistons in the lower portion of the casing beneath said ventilating openings, a fuel inlet to said chamber adjacent the upper end thereof, means for directing incoming fuel from said inlet along the surface of the fluid in the fuel chamber so as to permit any gas bubbles in the incoming fuel to pass. directly into the upper portion of the chamber, means for conducting fuel from said chamber to the pump cylinders including an orifice positioned in the lower portion of the chamber, a screen in said chamber intermediate the inlet and orifice for diverting gas bubbles in the fuel away from the orifice toward the upper portion of the chamber, and means for venting the upper portion of the fuel chamber comprising a passage in said casing, a valve for controlling said passage, a lever in said chamber for operating said valve, and a float secured to said lever and positioned on the orifice side of said screen.

2. A liquid fuel pump for internal combustion engines having, in combination, a casing having a plurality of cylinders and a fuel chamber above said cylinders, pistons in said cylinders, a fuel inlet to said chamber, a fuel outlet from said chamber for supplying fuel to the cylinders, means for removing gas from the upper portion of said chamber, and means for collecting fuel leaking along the pistons comprising grooves communicating with the piston surfaces intermediate their ends, and means forming conduits for conducting such leakage from the grooves to the upper portion of said chamber above the fuel level.

3. In a fuel injection pump comprising a plurality of piston and cylinder devices, a fuel supply chamber therefor positioned thereabove, means for removing gaseous fuel from the upper portion of the fuel supply chamber, means for collecting liquid and gaseous fuel leaking along each piston comprising an annular groove in each piston intermediate its ends, means forming conduits for conducting the liquid and gaseous fuel from said groove to said chamber above the fuel level therein.

4. In a fuel feeding system for internal combustion engines having a fuel pumping mechanism for supplying fuel to the engine under pressure, in combination, means forming a fuel supply chamber positioned above said pumping mechanism and provided with an inlet in the upper portion thereof, means including a conduit for connecting said inlet to a fuel tank, an outlet in the lower portion of said chamber for feeding fuel to the pumping mechanism, means in said chamber intermediate the inlet and outlet for preventing gas bubbles in the incoming fuel from reaching the outlet, means for venting gas from the upper portion of said chamber upon accumulation of a quantity of gas comprising a venting port in the upper portion of said chamber, a valve for controlling said port, a float operated lever for actuating said valve, and a check valve in the venting port for preventing reverse flow into the chamber through the venting port.

5. A liquid fuel pump for internal combustion engines comprising, in combination, a casing having a plurality of vertically positoned cylinders annularly arranged, a fuel chamber in the pump casing adjacent the upper ends of said cylinders, pistons in said cylinders, operating mechanism for said pistons in the lower portion of said casing, a fuel inlet to said chamber adjacent the top and at the periphery thereof, means directing the fuel entering the inlet horizontally into the chamber to avoid admixture of any bubbles chamber to the pump cylinders including an orifice positioned centrally in the bottom of said chamber so as to be spaced a substantial distance from the inlet, a generally vertically disposed screen in said chamber intermediate the inlet and the orifice for diverting gas bubbles in the fuel-away from the orifice and toward the upper portion of the chamber, and means for venting the upper portion of the fuei chamber comprising a passage opening into the top of said chamber on the inlet side of said screen, a valve controlling said passage, and a float in said chamber on the outlet side of said screen controlling said valve.

6. A liquid fuel pump for internal combustion engines comprising, in combination, a casing having a plurality of vertically positioned cylinders, a fuel chamber in the pump casing adjacent the upper ends of said cylinders, pistons in said cylinders, operating mechanism for said pistons in the lower portion of said casing, a fuel inlet to said chamber adjacent the top and at the periphery thereof to be removed from the heat of the operating mechanism, a plug threaded into said inlet having a vertical passage and an intersecting horizontal passage extending beyond the vertical passage to impart to the fuel a horizontal movement for discharge across the surface of the fuel, means for conducting fuel from said chamber to the pump cylinders including an outlet positioned in the bottom of said chamber to be spaced a substantial distance from the inlet, means for diverting gas bubbles in the fuel away from said outlet and toward the upper portion of the chamber, and means opening to the top of said chamber for venting the fuel vapor accumulated therein.

7. A liquid fuel pump for internal combustion engines comprising, in combination, a casing having a plurality of cylinders and a fuel chamber adjacent the upper ends of said cylinders, pistons in said cylinders, a fuel inlet to said chamber, a fuel outlet from said chamber for supplying fuel to the cylinders, means for venting gas from the upper portion of said chamber, and means for collecting fuel leaking along the pistons comprising a circumferential groove on each piston intermediate its ends for collecting the leakage fuel, a longitudinal groove on the piston communicating at one end with the circumferential groove, and a duct constantly in communication with the longitudinal groove throughout the working stroke of the piston and discharging into the fuel chamber above the level of fuel therein to avoid admixture of bubbles in the leakage fuel with the fuel in the chamber.

CARL F. HIGH,