US2136466A - Fuel supply system - Google Patents

Description

F. Ruz

FUEL SUPPLY SYSTEM Filed March 9 1955 sheets-sheet 1 A TTORNEY,

N0v.15,193s I i Hmz 2,136,466

' FUEL SUPPLY SYSTEM Filed March 9, 1936 Shams-Sheet 2 Patented Nov. 15, 1938 UNITED sTATEs FUEL SUPPLY SYSTEM Frederick Ritz, Hamilton, Ohio, assigner to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois Application March 9, 1936, Serial No. 67,879

8 Claims.

'I'his invention relates to improvements in fuel supply systems for internal combustion engines, and more particularly to an improved, self-priming fuel supply system having particular appli- 5 cation to liquid-fuel injection engines of Diesel type, or the like.

An object of the present invention is attained in the provision of an improved positive-pressure fuel supply system for engines of the type noted,

l in which the elements forming the system are advantageouslydisposed in a 'closed-circulation arrangement which is automatic and eicient to an improved degree in its purpose to supply fuel to the injection pumps of Diesel engines and the l like, and further, to provide a fuel supply system which is self-priming.

Another object is to be found in the provision of -an improved fuel supply system of closedcirculation type, in which certain of the elements included in the system are so operatively related as to tend to prevent a backflow of fuel 4 in the system, and further, in the provision of means associated with the organization of the engine fuel injection pump, yfor utilizing the ejector and pressure wave action of the excess fuel expelled or released by the pump, in maintaining a continuous unidirectional circulation .of fuel in the closed-circulation system.

A further object may be found in the provision, in combination with an inverted fuel pump, of an improved fuel supply system for engines of the type described, characterized by a positive pressure, continuously circulated fuel flow `in a closed circuit including the engine driven fuel injection pump, the system further including a fuel return header arranged substantially above a fuel delivery header, and a device for collecting and delivering to the return 'header the fuel in excess of the requirements of the 4;) pump, together with` excess fuel released by the pump plunger on its delivery stroke; .the present improvements objectively including provisions for removing from circulation, any air bubbles and vapor particles which might collect in the inverted pump chamber.

A still further object is attained in the provision, in an improved fuel system 0f the type described, of Imeans for conveying excess fuel released by the fuel injection pump, tothe fuel "0 return conduit of the system, the means comprising a nozzle-like conduit section having a fuelreceiving port or opening therein, disposed in the path of fuel delivery to the pump and arranged adjacently opposite the pump inlet port, whereby to receive the excess fuel released through the (Cl. 12S-139) inlet port, and to deliver such fuel to the return conduit of the system. The arrangement of the nozzle-like conduit relative tothe pump inlet port, is such that the ejector and pressure wave action of the excess fuel released under con- 5 slderable force by the injection pump,l may be utilized to great advantage, in the maintenance of a continuous circulation of fuel in the supply system.

Further objects and advantages will appear l0 from the following description of parts and the. accompanying drawings, in which:

Fig. l is a diagrammatic view of the assembled fuel supply system embodying the improvements of the present invention, the system being shown l5 as applied to an engine illustrated in sectional elevation; Fig. 2 is an enlarged fragmentary sectional view of an injection pump suitable for use 'in an engine of the type described, showing in connection therewith certain details of the pres- 20 ent invention; Fig. 3- is a digrammatic view of a fuel supply header and excess fuel return header system as applied to the fuel pumps of a multicylinder engine, and Fig. 4 is an enlargedfragmentary sectional view of an injection pump suitable for use in an engine of the type described, showi'ng in connection therewith certain details of the invention as modified with respect to the generally similar showing of Fig. 2.

. For convenience in description and by way of 30 example of its application, the fuel system presently to be described is illustrated as applied to an opposed-piston type of two-cycle, solid-fuel 'injection internal combustion engine, the engine illustrated preferably being of Diesel type. 3 Referring now to the drawings, the numeral I0 designates, generally, an engine of Diesel type, having its pistons I-I and I2 arranged for operation in opposed relation, in a common cylinder I4. The engine is illustrated as being of single 40 cylinder, opposed piston type, but may be of either single or multi-cylinder type utilizing single or opposed pistons in each cylinder. The cylinder I4 is provided with suitably arranged scavenging ports I5 and exhaust ports I6. Air 45 under pressure for scavenging purposes, is delivered to the ports I5 through the conduit I8 and annular air chamber I9, while the exhaust gases and air are discharged through the ports I6 into the annular chamber 20, and through an 50 exhaust conduit 2| to the atmosphere. The lower piston I I, which controls the opening and closing of the exhaust ports I6, is operatively connected to alower crankshaft 23through the connecting rod 24, While the upper pistonV which 55 in opposed-piston engines of the type described.

The engine is provided with fuel injection pumps 28 and 29, each thereof supplying fuel under pressure as through a conduit 30, to an injection nozzle structure 3|. Each of the injection nozzles 3| is shown as disposed to deliver fuel to the combustion chamber in the cylinder through an opening 32 in the side wall thereof,

this opening being located substantially midway between the ends of the cylinder. Since the injection pumps are identical in structure, only one thereof will be described in detail, the same reference characters applying equally to the corresponding parts of both pumps. However, it is to be understood that although the engine illustrated in Fig. 1 is of a type which utilizes a pair of injection pump and nozzle organizations for each cylinder, the fuel supply system presently to be described may be applied with equal facility to engines employing but a single injection pump for each cylinder.

Each of the injection pumps, shown as disposed in an inverted position in the present example, includes a pump casing 33, a stationary sleeve 34 within the casing and a pump plunger element 35 arranged for reciprocating movement in the sleeve. The plunger is operated by a cam element 36 on an engine driven cam shaft 31 (Fig. l). The volume of fuel delivered by the pump to the injection nozzle is regulated in accordance with engine load requirements, as by the mechanism generally designated at 38 (Fig. 2), having an operative connection (not shown), with the plunger 35. The mechanism 38, which may be operated by the engine governor (not shown) and its connection to the pump plunger, is well known and forms no part'of the present invention, hence no further description thereof need be given.

Referring to Fig. 2 which illustrates in cross section the lower or operating end of the pump, the casing 33 is provided with a fuel passage 39 through a wall portion thereof, the passage having a substantial sectional area, as shown. A fuel passage 4U of smaller sectional area than that of passage 39 is formed through a wall portion of the sleeve 34, the passage communicating on its outer end, through a slightly enlarged opening or port 4|, with the casing passage 36, and on its inner end with the displacement chamber of the pump. The lower or operating end of the plunger is cut away as at 42 to provide an annular fuel pocket or chamber 43 between the plunger and the sleeve 34, the arrangement of the cut-away portion defining the pocket 43, being such that the pocket is in direct communication with the sleeve passage 40, only during the latter part of the full delivery stroke of the plunger. Briefly, during the suction stroke of the plunger, fuel from a suitable source will be drawn into the pump chamber, defined by the lower end portion of the sleeve 34, and into the pocket 43 through the port 4| and passage 40. During the first part of the pump delivery stroke such fuel will be subjected to the loading of the plunger, and as the pocket 43 comes into communication with the passage 40, any excess fuel remaining in the chamber 43 will be ejected through the passage with considerable velocity, as such excess fuel is compressed to a slight degress since confined at this time under high pressure.

A chambered fitting element 44 having chambers 46 and 41 therein, separated by a central wall or partition 48, is secured in any suitable manner (not shown) to the pump casing 33 with the chamber 46 in communication with the casing passage 39 through a connecting passage 49 in a. Wall portion of the fitting member. A nozzle-like tube or conduit section 50 having an outwardly flared end 5| dening a port 52, is arranged with the bell end 5| disposed within the passage 39, and with the port 52 in juxtaposition to and spaced from the port 4| of sleeve passage 40. The opposite end of the conduit 50 communicates with the chamber 41 in the member 44, the conduit extending through the passage 49, chamber 46 and the partition or wall 48, the conduit being by preference, supported by and secured to the wall 48. The chamber 46 in the fitting 44 is in communication with a fuel supply header 54 through the pipe connection 55, while the fitting chamber 41 is connected with a fuel return header 56 through the pipe connection 51.

The system for supplying fuel to the injection pumps will now be described. In the first instance, fuel is supplied to the header 54 of each pump from a suitable storage tank 58 which may be located either remotely from or relatively near the engine mounting. A feed pipe or conduit 59 extends from substantially the lower or bottom portion of the tank, to a fuel supply pump 6D, whence the fuel is forced by the operation of the pump, through a conduit 6| having fuel filters 62 in circuit therewith, to a T-connection 63, and pipe or conduit 64 to a T-connection 65 from which extend branch conduits 66 and 61 to the supply headers 54 of the injection pumps 28 and 29, respectively. The return circuit for the fuel in excess of that utilized by the injection pumps, includes a conduit 68 connected to the return headers 56, as through the branches 69 and 69A, and leading to a completely enclosed, fuel-receiving tank 10 which may be and by preference is mounted upon the upper crank case 1| of the engine IIJ. A conduit 12 extends from the bottom portion of the tank 10 to a circulating pump 14, the pump being connected on its discharge end to the T-connection 63, as through a conduit 15. Thus a closed-circuit, fuel supply system is established, the circulating pump 14 drawing fuel from the tank 10 through the conduit 12 and delivering such fuel under pressure to the fuel supply headers 54 through the conduit 15, T-connection 63, conduit 64 and branches 66 and 61. A portion of the fuel so delivered is extracted by the injection pumps for consumption by the engine, and the excess thereof is returned to the tank 1|] through the return headers 56 and conduit 68. The closed circulation system is constantly replenished with fresh, filtered fuelby the supply pump 60 in forcing fuel from the supply tank 58, through the filters 62 to the T-connection 63 and thence into the system. The self-priming feature characterizing the present system is a result of the elevated fuel tank 16, the continuous infiow of fresh, filtered fuel to the closed circulatory system, as effected by the fuel pump 60, and the pressure wave created by the ejection of excess fuel from the injection pumps into the fuel return head- .ers 56, the combined function of which, once the fuel flow is initiated, tends to maintain the flow in a manner which will be apparent from the description.

The pumps 6l) and 14 may be separately driven by any suitable means (not shown), or they may be included as accessories or adjuncts of the engine organization l and hence driven thereby. With regard to'the filters 62,. it is desirable to connect at least two in the fuel supply line, to provide for an uninterrupted filtering of the fresh fueldelivered to the system, as such provision will permit one thereof to be in operation while the other is being cleaned or repaired.

As a means for removing or entrapping any air bubbles, emulsions, sludges and vapor particles collecting in the fuel circulation system,

`a vent valve 16 of suitable type such as a spring loaded, ball valve as illustrated in Fig. 1, is provided near the upper end, of the fuel-receiving tank 10. The valve 16 is connected by a vent duct 18 with the upper portion of the main supply tank 58, whence the bubbles and vapor particles delivered thereto may pass to the atmosphere through the vent 15 in the tank 58. In the closed fuel supply system shown and described, all air bubbles` emulsions, sludges and vapor particles will ultimately collect in the tank lll, and since the tank 'ill is mounted on the upper crankcase of the engine, the natural vib-rations'of the engine structure during engine operation, will be transmitted directly to the tank lll, hence `the fuel in tank 'it will be agitated to an extent that all air bubbles and vapor particles accumulating therein Will collect in the upper or top portion of the tank. When the volume of air bubbles, emulsions, sludges and vapor particles collecting in the upper portion of tank 'l'll is enough. to create sufficient pressure to open the vent-valve it, all foreign matter including the emulsions and sludges Will be ejected into tank t and the air and vapor will be vented to atmosphere in the manner described. linv order to prevent an undesirable degree of turbulence, there is pron vided in the tank lli, a baffle lill, located opposite the outlet of conduit (it.

In the operation of the improved fuel supply system herein described, the circulation pump llt maintains a continuous movement of fuel from the tank llt, through the pump, to the fuel supply header tit of each injection pump, whence the fuel flows to the fuel pump casing passage t9. A portion of the fuel so delivered will be utilized by each injection pump, in accordance with its governed demand, and the excess fuel remaining will flow from the passage lit into and through the conduit t@ to the return header 5t, whence it is returned to the tank lili. Also, any excess fuel delivered to the injection pump chamber will be released by the plunger during a portion of its operating stroke, and such fuel will be delivered to the return header tit in a` manner presently to be described. lThe supply pump tit Y may operate continuously to replenish the closed circulating -"system with fresh, filtered fuel.

A particular feature of this invention is to be found in the provision of the nozzle-like tube 5|] which is arranged with its fuel-receiving end 5l and inlet p'ort 52 slightly spaced from and located oppositely and substantially in regisr with the inlet port lll of the fuel passage t0 in the plunger-sleeve 34. The injection pumps are by preferenceI mounted in aninverted position, and each thereof effects' a pressure release of excess fuel delivered to the pump chamber, which excess fuel is ejected as a result of the operation of the pump plunger, through the passage 40, across the space intervening the outer opening or port 4| of the passage 40 and the inlet end 5I of the tube 50, through the port 52 and into the tube 50, thence through the tube to the return header 56. With the pump in an inverted position, any air bubbles, emulsions, sludges and vapor particles will tend to collect in the top portion of the fuel space in the pump plunger. However, when the excess fuel under pressure in this space is ejected at a high velocity through the sleeve passage 40 and into the tube 50, theforeign matter, bubbles and vapor particles will be carried along with and entrained by such fuel, through the return header 56 and conduit 68 to the separator tank 10. Hence it Will be readily observed that the ejector and pressure-wave action of the excess fuel so released, will not only remove foreign matter, air bubbles and vapor the excess fuel across the space between the passage tt and the inlet end 5i of the tube will tend toA prevent, in addition, any part of such excess fuel from returning to the supply header.

vThe ejector action of the excess fuel is certain circumstances, sufficient to maintain circulation of fuel in the closed circuit syste Without the use of a separate forced, circulation device, such as the pump lll. For example, if the capacity of the injection pumps be substantially in excess of injection requirements, volume of by-passed or excess liquid fuel is such. as denitely to create and maintain a circulation through the system, Without the necessity of a separate pump for this purpose. Under these conditions each injection pump serves the dual purpose of an injection, as Well as a circulating agency, the ejector orasplrating action of the element til' and associated parts serving more than adequately to maintain for the pump a plentiful supply of fresh clean liquid fuel at all times. in this case the pump "it may be disconnected from its driving means, and a shunt or ley-pass conduit connected between the conduits 712 and liti. Such a by-pass connection is shown at tt, Fig. l. A. two-'way valve tl, which may be of conventional type, is provided at the juncture of the by-pass conduit ttl and conduit l2 for connecting the by-pass in the circulation system.

. pair of fuel pumps 89 and 99 preferably arranged on opposite sides of the cylinder in a plane which is substantially at a right angle to the longitudinal axis of the engine, i. e., the engine crankshaft axis. Thus a row of fuel pumps 89 are disposed on one side of the engine, and a similar row of pumps 90 on the opposite side of the engine.

Fuel oil from the supply system described in connection with the engine of Fig. 1, is delivered through the supply pipe or conduit 9| to the T-connection 92, from which branch conduits 93 and 94 extend tothe first or right-hand pair of pumps 89 and 90 respectively. The described fuel connections correspond respectively to the connections 64, 65, 66 and 61 shown in Fig. 1. The fuel inlets of the pumps 89 are interconnected through a supply header 95, the header being supplied with fuel from they branch conduit 93. Similarly, the fuel inlets of the injection pumps 90 are interconnected through a supply header 96 which is supplied with fuel from the supply branch conduit 94. Fuel return headers 91 and 98, overlying respectively the branch supply lines 95 and 96, interconnect the outlets of the pumps 89 and 90 respectively, with both return headers connected to a common excess fuel return conduit 99 through branch conduits |00 and |0|. The latter` are connected ,respectively to the return headers 91 and 98. The connections 99, |00 and |0| of Fig. 3 correspond respectively in function, to the connections 68, 69 and 69A shown by Fig. 1.

For those engines utilizing but a single injection pump for each cylinder, the fuel supply system would appear substantially like that shown in Figs. 1 and 3, with the exception that the arrangement shown by Fig. 3 would include but a single row of injection pumps, say the row of pumps 89 supplied with fuel from'the branch conduit 93 and supply header 95, the excess fuel of course being returned to the circulatory system through the return header 91 and return conduit 99.

Fig. 4 illustrates in sectional elevation the lower or operating end of an injection pump, the view being similar to that of Fig. 2 but showing certain modified features in the structure thereof. The pump comprises a casing |05 having an externally bossed portion |05 on one side thereof, the boss providing a plane surface |01 to which is secured in any suitable manner (not shown) a fitting member |08. A sleeve |09, serving as a guide for the pump plunger ||0, is secured within the casing |05 and is provided with a fuel passage through a wall portion thereof. A fuel passage |2 extends laterally through a portion of the boss |06, and the sleeve |09 is so disposed within the pump casing as to effect a radial alignment of the sleeve passage with the Ipassage I2. A second fuel passage 4 is formed through the boss |06, this passage by preference being sloped upwardly and inwardly of the casing Wall. The inner end of this last passage is in communication with the passages and ||2 through a somewhat arcuately slotted passage or recess |5 formed in a peripheral portion of the sleeve |09, in the manner illustrated in Flg. 4.

The fitting member |08 carries a fuel supply header ||6 and a fuel return header ||1, the headers being mounted in suitable seat portions ||8 formed on the member, and secured thereto as by welding at ||9. The supply header ||6 communicates with the pump passage I4 through a connecting passage |20 formed in the fitting member |03. Similarly, the return header is in communication with the pump passage ||2 through a connecting passage |2| in the fitting Y member.

The closed circulatory fuel supply system described in connection with the engine of Fig. 1, supplies fuel to the header IIB, from which the fuel flows under the pressure existing in the system, through the passages |20, H4, ||5, ||2 and 2| to the return header ||1. The fuel received by the header ||1 is returned to the circulating system in the manner heretofore described. During operation of the engine, and therefore of the fuel injection pump, the pump will draw fuel from the described flow of fuel from supply header ||6 to the return header ||1, the fuel flowing through passage into the pump displacement space or chamber. Such fuel as is unused by the pump upon each delivery stroke, will be ejected through passage into the passage ||2. The momentum of the excess fuel thus ejected is normally sufficient of itself to prevent a backflow of the excess fuel into the supply header 6. In brief, the operation of the modified pump organization of Fig. 4 is similar to that described for the pump embodiment of Fig. 2.

Throughout the drawings, suitable arrows are provided to indicate the direction of fuel flow in the fuel supply system.

The presently described embodiment and improved features of this invention provides a fuel supply system which is fully automatic in its operation and is self-priming and self-venting. It is to be understood, of course, that the invention is not limited to the particular system and improved features thereof described and illustrated, but that alterations or modifications may be made in the parts, combinations and arrangements thereof without departing from the spirit and full intended scope of the invention, as defined by the appended claims.

I claim:

1. In a liquid-fuel injection system for internal combustion engines, an injection pump provided with a fuel inlet port, means forming a supply chamber communicating with said pump inlet port, a supply connection to the chamber, an outletconnection from the chamber, a tubular conduit element in said chamber, provided for conducting fuel from the supply connection to the outlet connection through said chamber independently of the pump said tubular conduit having its inlet end spaced from and in line with said pump inlet port, and conduit means connecting the supply and outlet in a continuous circulating system.

2. In a liquid-fuel injection system for internal combustion engines, an injection pump of a type having a displacement capacity in excess of injection requirements, the pump including a pump chamber and a port communicating therewith, said port providing both a fuel inlet and an excess fuel outlet for said pump chamber, and a-system of conduits arranged, in-

l dependently of the pump structure, for continuously circulating a supply of fuel to and from the pump, said system including a fuel reservoir having a continuous connection with the pump through said pump port, an inlet connection and an outlet connection, each associated with the reservoir, conduit means connecting the outlet connection to the inlet connection, and means constituted by elements of said system and including a short conduit section of reduced diameter, disposed within the reservoir adjacent the pump and in the line of flow of excess fuel from said pump port, and tending to create a circulation of liquid fuel through the system.

3. In a liquid-fuel injection system for an internal combustion engine, an injection pump, a

'por particles from the system, said means-lncluding a fuel and vapor separator located on the engine and above said fuel supply reservoir and the supply tank.

4. In a liquid-fuel injection system for an internal combustion engine of multi-cylinder type, a system of fuel delivery and return conduits arranged in closed circuit relation for the continuous circulation of liquid fuel, means for supplying fuel to said system, including a fuel supply reservoir in the system, an injection pump for each cylinder of a type having a displacement capacity in excess of injection requirements, `said pumps being connected to said systemin parallel, between said fuel delivery and return conduits, and means located in the system adjacent each pump, utilizingl the expulsion of excess fuel from the pump, concurrently to promote a positive and continuous circulation of liquid in the system, and to induce a flow of fresh fuel from the system to the pump.

5. In combination with an injection pump of a type having an excess-fuel discharge port, a pump fitting formed of a lpair' of mating elements, each of said elements being provided with connecting bores forming a pair of passages through the fitting, outer portions of the `fitting being formed to receive a fuel supply conduit and a fuel return conduit located for connection respectively with said passages, a portion of the pump structure being formed to provide an arcuate recess of appreciable extent in a direction axially of the pump and adjacent the fitting, and the fitting being formed so that the passages therethrough open into said recess, the recess being in communication at one end with the excess-fuel discharge port of the pump, and a portion of the passage through the fitting to the return conduit, being in register and in substantial alignment with said port.

6. In an injection pump assembly for-engines of the type described, an injection pump-of a type having a displacement capacity in excess of injection requirements, said pump including a pump cylinder having a passage through a wall portion thereof, a sleeve in said cylinder having a fuel port therein in communication with said passage, a pump plunger operable in said sleeve, a hollow member provided with separate chambers therein, one of said chambers being in communication with said cylinder passage, a fuel supply header in communication with said lastmentioned chamber, a fuel return header in communication with the other of said chambers, and a conduit extending from said other chamber through the first said chamber and into said cylinder passage, said conduit having an open end spaced froml but aligned with the fuel port in said sleeve and adapted to receive excess fuel released by said plunger on its delivery stroke.

7. In an injection apparatus for an engine of liquid-fuel injection type, an injection pump, a fuelfeeding system including a' fuel supply tank communicating with the pump, a device connected into said system for separating. foreign matter from the fuel therein, said device comprising` a substantially closed container located above saidinjection pump and mounted on the engine so as to be subject to enginevibration to elect an agitation of the container, the container having a supply connection to its upper portion, and an outlet connection from its lower portion, means within the container tending normally tol maintain a body of liquid therein, and a vapor space above the liquid, an outlet connection from said vapor space, and a vent duct having its inlet at the last said connection and its outlet in the upper portion of said supply tank.

8. In a liquid fuel injection apparatus for internal combustion engines, aninjection pump, a fuel supply system including a supply tank communicating with said pump, a device in the fuel system tending to entrap and separate from the fuel therein, foreign matter, air and vapor particles, said device comprising a container located above said injection pump and mounted on a portion of the 'engine subjected to engine vibration to effect an agitation of the container, the container being supplied from said system by connection to an upper portion thereof, and provided With a liquid discharge `port in a lower container portion, the container being so related to the system as normally to maintain in its upper portion a space above a body of liquid therein, a vent duct extending from said space into said supply tank, and a check valve in the vent-duct adapted to eliect a permanent separation of foreign matter, air and vapor particles from said container space. y

FREDERICK RITZ.

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