US3125078A

US3125078A - Fuel supply system

Info

Publication number: US3125078A
Authority: US
Publication date: 1964-03-17
Anticipated expiration: 1981-03-17

Description

March 17, 1964 N. M. REINERS 3,125,078

FUEL SUPPLY SYSTEM I Filed Jan. 16. 1961 2 sheets-shed 1 2-; m n n W n 6.3T

mmvrgx United States Patent 3,125,078 FUEL SUPPLY SYSTEM Neville M. Reiners, Qolumbus, Ind, assignor to Cummins Engine Company, lino, Columbus, Ind, a corporation of Indiana Filed Jan. 16, 1961, Ser. No. 82,781 4 Claims. (Cl. 123-32) This invention relates generally to a fuel supply system for a multi-cylinder internal combustion engine, and more particularly to a novel fuel supply arrangement for a diesel engine of the foregoing type.

Accordingly, it is the general object of the invention to provide a novel fuel supply arrangement for an internal combustion engine, which is of simplified construction.

A more particular object is to provide a novel fuel supply arrangement for supplying dual to the injectors of a multi-cylinder diesel-type internal combustion engine, which eliminates the necessity of external supply' and return lines with branch lines connected to each injector.

Still another object is to provide a novel fuel supply arrangement of the foregoing character which eliminates the necessity of connecting and disconnecting fuel lines to each injector during installation and removal thereof.

A more specific object is to provide a novel fuel supply arrangement tor supplying fuel to the injectors of a multicylinder diesel-type internal combustion engine having the injectors thereof mounted in the cylinder head of the engine which permits connection of the fuel supply and return lines to the injectors to either end of the cylinder head or both ends thereof.

Still another object is to provide a novel fuel supply and injector arrangement for supplying fuel to the injectors of a diesel-type multi-cylinder internal combustion engine which permits of a reduction in cost of the engine.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a side elevational view on a reduced scale of an internal combustion engine of the diesel-type, incorporating a fuel supply arrangement embodying the features of the present invention;

FIG. 2 is an enlarged liragrnentary plan view of a portion of the cylinder head of the engine illustrated in FIG. 1;

FIG. 3 is an enlarged transverse sectional view, with some parts in elevation, taken along the line 33 of FIG. 2;

FIG. 4 is a fragmentary horizontal sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged longitudinal sectional view taken along the line 55 of FIG. 4; and

FIG. 6 is a view similar to FIG. 5 taken along the line 6-6 of FIG. 4.

Briefly described, the present invention contemplates a novel fuel supply system for supplying fuel to the injectors of a diesel-type multi-cylinder internal combustion engine, the injectors being mounted in the cylinder head of the engine and each having a nozzle at the lower end thereof communicating with a cylinder of the engine for injecting metered quantities of fuel therein. Each injector may have the construction disclosed in the Reiners Patent No. 2,727,498, issued December 20, 1955. Such an injector has an elongated body and includes a fuel duct or passage therein for receiving a circulating how of fuel therethrough. A fuel chamber is provided in the body adjacent the nozzle into which metered quantifies of fuel are directed for injection into the cylinder. Fuel is metered into the chamber from the circulating flow through an interconnecting metering orifice during a portion of each stroke of a reciprocably mounted injector plunger in the injector body and movable in timed rela- 3,125,078 Patented Mar. 17., 1964 2 tion with the speed of the engine, the plunger also serving to inject the fuel from the chamber through the nozzle and into the cylinder. Fuel is delivered under pressure to one end of the iiuel duct of each injector from a fuel supply unit or source, and excess amounts of fuel are discharged from the other end of each injector duct for return to the unit by means of the novel fuel supply arrangement of the present invention. The fuel supply arrangement to be hereinafter described, eliminates the usual external supply and return lines, and associated lbranch lines which are connected to each injector. According to the present invention, such lines are formed internally of the cylinder head of the engine so as to communicate with each end of the fuel duct in each injector when the injectors are mounted in the head. Such arrangement permits greater flexibility in the connections of the fuel supply and return lines from the fuel supply unit to the cylinder head of the engine in that the lines can be connected to either end of the head with the other ends being plugged, thereby providing a greater latitude in the mounting of the engine and its related accessories.

In FIGS. 1 and 2, a typical diesel-type internal combustion engine is illustrated, which incorporates a fuel supply arrangement embodying the features of the present invention. The engine is conventional to the extent that it includes a cylinder block 11, cylinder head 12, and a valve cover 13. In the present instance, the engine is of the six-cylinder in-line overhead valve type. It will be understood, however, that the instant fuel supply arrangement is also applicable to engines of other numbers of cylinders and to engines of other than the in-line type.

The cylinder block 11 includes the usual piston, connecting rod and crankshaft arrangement (not shown), and being of the overhead valve type, sets of valves, indicated at 14 in FIG. 2, are mounted in the cylinder head 12 and are adapted to be actuated by a camoperated valve gear arrangement, also not shown. Inasmuch as the engine is of the diesel type, a plurality of fuel injectors, indicated at 15 (FIG. 2), are also mounted in the cylinder head 12, and centrally of the sets of valves 14, of which in this instance there are two intake and two exhaust valves arranged as illustnated in the figure.

The engine also includes a fuel supply unit 16 preferably of the type disclosed and claimed in the Neville M. Reiners Patent No. 2,727,498, issued December 20, 1955. Such a unit is adapted to supply fuel under pressure to each of the injectors 15 by a supply line 17 and to return excess amounts of fuel to the unit 16 by a return line 18. The unit 16 is also adapted to vary the pressure of the fuel supplied to the injectors in accordance with a particular engine operating condition. The fuel supply unit 16 thus comprises a source of fuel under pressure for the injectors 15.

Each injector 15 has an elongated body 19* (FIGS. 3, 5 and 6), a nozzle 20 in the form of a tapered cup threaded onto the lower end thereof, and a sleeve 21 adapted to enclose the nozzle 20 and a major portion of the body 19. The sleeve 21 extends through the water passages, indicated at 22, in the head 12. The body 19 is mounted in a longitudinal bore or cavity 23 in the cylinder head 12, each cavity 23 comprising a series of concentric, varying diameter portions tor engaging complementally sized varying diameter portions of the injector body 1 9. The lower end of the cavity 23 is tapered as at 24, to provide a seat for the lower end of the injector body, indicated at 25, which is also tapered. A clamp 26 (FIGS. 2 and 3) maintains the injectors on their seats 24.

'Each injector 15 has a fuel duct or pass-age therein for receiving a circulating flow of fuel under pressure there-through from the fuel supply unit 16, metered quantities of which are cyclically injected from a chamber in the injector into the cylinder. One end of the fuel duct communicates with the supply line .17 and the other end communicates with the return line 18 to provide a circulating flow of fuel through the duct. The duct includes a supply portion, an intermediate portion, and a return portion. The supply portion includes a series of interconnected bores and passages within the injector body 19 terminating at the lower end thereof adjacent the nozzle 20 where it is connected to the intermediate portion.

In FIGS. and 6, a series of interconnected bores and passages in the body 19 are illustrated which comprise the supply, intermediate and return portions. While such bores and passages are shown in the same plane in the figures for purposes of clarity, they are actually angularly spaced from each other, as indicated in FIG. 4. Thus, in FIG. 5, the supply portion comprises two longitudinally spaced sections, namely, a first section and a second section, the sections being adapted to be connected to each other during a portion of the operating cycle of the injector. The first section comprises a transverse passage 31 in the injector body 19 (FIG. 5). The second section of the supply portion includes a second transverse passage 32 spaced longitudinally from and below the passage 31 and a longitudinally extending passage 3-4 which is connected at its upper end to the passage 32 and terminates at its lower end at a connection with the intermediate portion, indicated at 35, of the duct adjacent the lower end of the injector body 19'. Thus, when connected, the first section or transverse passage 31, the second section which includes the transverse passage 32 and longitudinal passage 34, comprise the supply portion of the fuel duct.

The intermediate portion 35 is formed between the lower end of the injector body 19 and the nozzle 20. Thus, the intermediate portion 35 comprises an annular chamber or space formed between a reduced section 37 of the injector body 19 and an internal surface of the nozzle 20. The nozzle also includes an internal surface, indicated at 38, which is tapered and provided with a plurality of radial holes or openings 39 at the remote lower end thereof which comprise discharge outlets for 261161.

In order to define a chamber within the injector nozzle 20 from which fuel is expelled into the cylinders, each injector .15 is provided with an elongated plunger 40 which is reciprocably mounted in a central longitudinal bore 41 in the body '19. The lower end, indicated at 42, of the injector plunger 40 is complementally tapered to lit the taper of the internal surface 36 of the nozzle 20 when in a full down position, as illustrated in FIG. 6. When the plunger 40 is raised, as in FIG. 5, a fuel chamber 43 is formed between the lower end 42 of the plunger and the internal surface 38 of the nozzle 20.

In order to provide an inlet to the chamber '43 from the intermediate portion 35, a small transverse bore or metering orifice 44 (FIG. 6), is provided in the injector body 19 for controlling the amount of fuel entering the chamber 43. The quantity of fuel entering the chamber 46 depends upon the pressure of the fuel at the orifice 4 4 and the time that the orifice is open. Opening and closing of the orifice 44 is controlled by movement of the plunger 40 in its bore 41. When in a full down position, the tapered lower end 42 of the plunger completely fills the chamber 43 to reduce the volume thereof to zero (FIG. 6). The metering orifice 44 is spaced slightly above the tapered portion of the chamber 4-3 and opens into the plunger bore 41 so as to be opened by the full diameter portion of the plunger 40 during a portion of the stroke thereof.

To open the supply portion of the fuel passage through the injector and connect the two sections thereof, the transverse passages 31 and 32 extend inwardly to the plunger bore 4 1. To connect the passages 31 and 32, the plunger 4-0 is provided with a reduced diameter portion 47 defining an annular space 48 within the bore 41. The reduced portion 4-7 is located on the plunger 40 such that when the lower end 42 of the plunger is seated against the surface 38 of the nozzle 20, the first section or passage 31 is closed by the body of the plunger 40. When the plunger 40 is moved upwardly, the reduced portion 47 moves opposite the passage 31 to open the latter to the annular space 48. The length of the reduced portion 47 is such that when the passage 31 is connected to the space 48, the passage 32 of the second section is also connected. Thus, the space 48 constitutes a part of the supply portion of the fuel duct. The arrangement of the transverse passages 31 and 32 and the metering orifice 44 is such that the supply portion is opened before the metering orifice 44 is open and remains open for a period after the metering orifice closes. A flow of fuel is thus established through the duct to assist in purging air and gases from the duct before fuel is metered through the orifice 44 into the chamber 46.

The return portion of the duct through the injector 15 is illustrated in FIG. 6 and comprises a second longitudinal passage 51 in the injector body 19, the passage 51 extends upwardly from the chamber or intermediate portion 3 5 and is enlarged as at 52 at a distance from the intermediate portion. The portion 52 is intersected by a short transverse passage 54 extending inwardly through the body 119. To maintain pressure in the intermediate portion 35 and hence at the metering orifice 44, a restriction is provided in the return portion of the fuel duct. Such restriction in this instance comprises a plug 56 having a small axial hole 57 therethrough, the plug 56 being mounted in a counterbore 58 at the lower end of the passage 51.

With the foregoing construction, it will be apparent that accurately metered quantities of fuel will be injected into the cylinder of the engine during each stroke of the plunger 46, depending upon the pressure at the metering orifice 44 which is controlled by the fuel supply unit 16, and the time the passage 31 is open. Such pressure is varied in accordance with the operating condition of the engine and its fuel requirements.

In order to connect the supply and return lines .17 and 18 to the supply and return portions of each injector duct, separate branch lines to each portion of each injector have heretofore been employed, the branch lines in turn being connected to common fuel supply and return lines or rails. Each rail is connected to the supply and return lines 17 and '18 leading to the fuel supply unit 16. With such an arrangement, it is necessary to connect and disconnect the branch lines to each injector in order to effect an installation or removal of the injectors from the engine. Such a procedure is time consuming and, because of the presence of the branch lines and the common rails, the total cost of the engine is increased.

The present invention overcomes each of these disadvantages in that it eliminates both the individual branch lines to each injector as well as the common supply and return rails. Moreover, the present fuel supply arrangement penmits of a greater flexibility in the manner in which the fuel supply and return lines may be connected to the engine and thus to each injector 15.

Thus, according to the present invention, the cylinder head i1 2 is provided with a fuel supply passage within the head for delivering fuel from the supply line 117 to the supply portion of each injector, and a return passage for returning discharged or excess amounts of fuel from the return portion of the injectors to the return line 18. In the present instance, the supply and return passages'comprise a pair of longitudinal bores 61 and 6-2 (FIG. 3), respectively, which extend between the front and rear ends, 63 and 64, respectively, of the cylinder head 12. The

bores

61 and 62 are arranged so as to intersect the cavities 23 in which the injectors 15 are mounted, and

are spaced vertically such that the lower bore 61 is in general horizontal alignment with the end or inlet 31 of the supply portion of each injector and the upper bore 62 is in horizontal alignment with the end or cutlet 54 of the return portion of each injector. The ends of the

bores

61 and 62 are threaded to receive either plugs (not shown) or pipe fittings 66, which serve to connect the supply and return

lines

17 and 18 to the

bores

61 and 62, respectively; As illustrated in FIGS. 1 and 3, both the supply and return

lines

17 and 18 are connected to the open ends of the

bores

61 and 62 at the front end 63 of the cylinder head. However, because the bores 61 and '62 extend completely through the head '12, the

lines

17 and 18 could also be connected to the rear end 64 of the cylinder head, or the lines could be alternately connected to the front end 63 and rear end 64 of the cylinder head 12. In each case, the opposite open ends of the bores '61 and 62 are closed by plugs.

In order to provide for a flow of fuel between adjacent injectors, each injector body :19 is provided with a pair of

circumferential grooves

71 and 72, the groove 71 being in alignment with the inlet 31 and the groove 72 being in alignment with the outlet 54. The recesses '71 and 72 thus provide continuations of the

bores

61 and 62 and are sufficiently deep so as not to retrict the fuel flow between radjacent injectors. In addition, the groove 71, may be so formed to receive a screen 73 and retainer 74 for preventing the entry of foreign particles into the fuel duct passages of the injector. No screen is, of course, necessary around the outlet 54.

In order to equalize or balance the flow of fuel entering the supply portion of each injector duct, a restriction may be provided in the transverse passage 31 of each injector 15. Such restriction in this instance comprises a plug 76 having an axial bore 77 therethrough, the plug 76 being seated in the outer end of the passage 31. The plug 76 in each injector thus serves to equalize the efiects of pressure variations in the bore 61. In addition, the plugs 76 may be replaced with others having a different size opening 77 to compensate for variations in the metering action of a particular injector.

Thus, the fuel supply system of the present invention is effective to permit the

fuel lines

17 and 18 from the fuel supply unit 16 to be connected to the engine in a Variety of locations and arrangements such as are necessitated by a particular installation. Equally important is the fact that the present arrangement also eliminates the necessity of the usual supply and return branch lines and rails which are connected to the individual injectors and the supply and return lines of the fuel supply unit. Moreover, the necessity for rotatably indexing the injectors in their respective bores is also eliminated because of the

grooves

71 and 72 around the inlets 31 and outlets 54.

I claim:

1. The combination of a cylinder head for an internal combustion engine having a plurality of cylinders and having a plurality of fuel injectors mounted in said cylinder head for supplying fuel to the respective cylinders, said cylinder head being provided with a fuel supply bore and a fuel discharge bore formed longitudinally therein and said bores being spaced from each other and each extending from an opening formed at one end of said cylinder head, said openings defining ports adapted to be connected respectively to a fuel supply line and a fuel discharge line, said fuel injectors each having a circumferential inlet groove formed therein, said inlet groove being aligned with and communicating with said fuel supply bore at longitudinally spaced points along the length thereof intermediate the ends of said cylinder head, each of said fuel injectors having a circumferential outlet groove formed therein, said outlet groove being aligned with and communicating with said fuel discharge bore at longitudinally spaced points along the length thereof intermediate the ends of said cylinder head, said circumferential inlet and outlet grooves each forming a continuation of the flow path provided by said bores and permitting the free flow of fuel around the respective injectors between points in the respective bores on either side of said injectors.

2. The combination of a cylinder head for an internal combustion engine having a plurality of cylinders and having a plurality of fuel injectors mounted in said cylinder head for supplying fuel to the respective cylinders, said cylinder head being provided with a longitudinal fuel supply bore and a longitudinal fuel discharge bore spaced therefrom, each of said longitudinal bores extending entirely through said cylinder head between corresponding end openings provided in the opposite ends of said cylinder head, said fuel supply bore communicat ing with the inlets of said injectors at spaced points between the respective end openings thereof, said fuel discharge bore communicating with the outlets of said injectors at spaced points between the respective end openings thereof, a fuel supply line selectively connected in the opening at one end of said fuel supply bore for supplying fuel to said injectors, a fuel discharge line selectively connected in the opening at one end of said fuel discharge bore, and plug means secured in the other ends of said bores, each of said injectors being provided with a circumferential inlet groove aligned with and communicating with said fuel supply bore and also being provided with a circumferential discharge groove aligned with and communicating with said fuel discharge bore, said grooves in said injectors forming continuations of the flow paths provided by said bores for the free flow of fuel around the respective injectors.

3. The combination of claim 1, wherein each of said injectors includes an inner chamber and wherein each of said circumferential inlet grooves communicates with the inner chamber of the respective injector through a duct provided with a removable restriction having a pre-selected flow capacity for equalizing fuel flow to the respective injectors.

4. The combination of claim 3, wherein each circumferential groove connected with said fuel supply bore is provided at the bottom thereof with an annular screen overlying the adjacent end of said duct.

References Cited in the file of this patent UNITED STATES PATENTS 1,589,982 Muller June 22, 1926 2,612,884 Reggio Oct. 7, 1952 FOREIGN PATENTS 258,175 Germany Mar. 31, 1913 1,006,542 France June 23, 1952