US2384011A - Fuel injection apparatus - Google Patents

Description

. Sept- 4,1945- A.-'r..BREMsER FUEL INJECTIQN APPARATUS ,Filed April 1:1942

Patented Sept. 4, 1945 Albert T. Bremser, Sidney, N. Bendix Aviation Corporation, a corporation of Delaware assignor to South Bend, Ind.,

Application April 1, 1 942, Serial No. 437,154

20 Claims. 'I'his invention relates to fuel injection apparatus and more particularly to means for delivering fuel 'under pressure to the cylinders of a solid fuel injection engine.

One of the objects of the present invention is to provide novel apparatus of the above character whereby the fluid pressure of the fuel in the delivery line is relieved after each injection of fuel into the engine cylinder.

Another object of the invention is to provide a novel fuel injection pump including a novel delivery valve whereby pressure surges in the delivery line betweenthe pump and the engine cylinder are effectively damped or substantially eliminated.

A further object is to provide a. novel fuel pump adapted to provide supply line relief for the pressure in the deliveryline after the injection stroke Without danger of introducing air pockets or creating a, suction in said delivery line.

held in end to end engagement by a combination gland nut and casing member I3, the latter having threaded engagement with the upper, inner end of casing I0. Slidably mounted for reciprocating movement in cylinder II is a piston or plunger I4, which is preferably actuated and controlled in any suitable and well-known manner, such as shown in Bremser Patent No. 2,265,

997. To adjust the angular .position of said piston relative to said cylinder, a rack and pinion mechanism of well-known construction is prefer,- ably provided, only rack I5 of said mechanism being shown in the drawing.

, Extending radially through the wall of cylinder II is4 a fuel inlet or suction port I6 which connects the bore of said cylinderwith an annual Still another object is to provide a novel fuel injection pump adapted for feeding fuel to an ine jection nozzle of the open type so as to obviate any dribbling of fuel from said nozzle after the injection stroke of the pump.

A still further object of the invention is to provide a. novel apparatus of the above nature in which the pressure in the delivery line is relieved by timely communication of the latter with the .fuel supply or by-pass line.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not intended as a denition of the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

In the drawing, wherein like reference characters refer to like parts throughout the several views, e

Fig. l is a side elevation, partly in section and with parts broken away, of one form of fuel injection Vpump and delivery valve embodying the present invention; and,

Fig. 2 is a'. similar view of the invention with broken away.

One embodiment of the present invention is illustrated in Fig. 1, by way of example, in the form of a fuel injectionpump comprising a me-I tallic casing I0, in the central bore of which a cylinder II and adelivery valve adapter I2 are of another embodiment the l'ower end thereof channel I'I provided in casing III, said channel communicating with the fuel supply source (not shown) through anv inlet passage I8. Disposed beneath port I6 and extending radially through the wall off said cylinder is a relief or by-pass port I9 which also connects with channel II. The latter is preferably formed in a hard metal sleeve or insert 20 around-which casing I0 may be cast, said sleeve, as shown, 4being provided with a baille 2| extending for at least a portion of its periphery to separate the channel portions connecting with ports I6 and I9.

To control the fuel ilow from the pressure chamber which is formed in the upper end of cylinder II lbetween piston I4 and adapter I2, a novel delivery valve comprising a stem 22 and a head 23 is slidably mounted for reciprocating movement in the central bore of said adapter.

In the closed position thereof, valve 22, 23 has the reduced lower end of stem 22 in fluid-tight engagement with an internally extending shoulder or seat 214 in the lower end of said adapter. As shown, the engaging surfaces of said shoulder and stem are conical in shape but a flat or other type' valve seat may .be employed. A second fluid seal is obtained at the upper end of valve 22, 23 by engagement of cylindrical portion or retraction collar 25 of stem 22 with the wall of the adapter bore. A plurality of axial utes 26 are h preferably formed in the periphery of said valve stem to .provide fuel passages from the lower end of said stem to the cylindrical portion 25. A spring 21 is contained in member I3 and engages head 23 ofsaid valve to urge the latter in the direction of seat 24, said spring being guided by a, member 28 which also serves to limit the upward movement of said valve. The upper end of member I3 is adapted to have a delivery conduit (not shown) connected thereto at 29, said conduit pressure built up above the piston and fuel flowsv past seat 24, along flutes 26 into the delivery line and thence to the delivegy nozzle at the engine cylinder. To cut off the fuel injection during the upward or pressure stroke of plunger I4 at a desired point in the stroke, a helical groove 3D is provided in the wall of said plunger for cooperation in a well-known manner with by-pass port I9, said groove being connected to they pressure chamber of the pump by an axial passage 3| and a transverse passage 32. The latter extends diametrically through said plunger and has one end thereof connecting with groove 30 and the other end with a second helical groove 33 which is similar to groove 30, said grooves being symmetrically disposed in respect to the axis of said plunger.

Novel means are provided for relieving the pressure and eliminating pressure surges in the delivery line after fuel injectioncut-off and, as shown, said means comprise a central relief passage 3-4 extending through valve head 23 to communicate with a central recess 35 of enlarged diameter in valve stem 24, said head being threadedly secured in the upper end of said recess. A check valve 36, preferably of lthe ball and spring type, is disposed in recess 35 to prevent fuel ow from said recess 'through passage 34, i. e., 4in the direction of the delivery line, the lower portion of said recess having a decreased diameter to provide a shoulder 31 for supporting the spring -cf said valve. A plurality of radial passages 38 connect recess 35 to an annular groove 39 provided in the internal wall of adapter |2 above seat 24. Groove 39 communicates with an annular groove 4| inthe base of said adapter by means of a plurality of connecting passages 42, the latter groove being in turn connected by an axially extending passage 4 3 in the wall of cylinder II to a relief port 44 which is coaxial with and disposed diametrically opposite by-pass port I9 to connect with the bore of said cylinder. The outlet of port 44 is similar in Shape to that of port I9 so that said ports are simultaneously connected to and disconnected from each other and the pressure cham-her of the pump by helices 30 and 33, respectively, during the piston stroke.

In operation, the fuel pressure in the pressure chamber begins to build up during the upstroke of the piston when the edge of the latter moves past inlet port I6 to close said port. The fuel pressure acts to raise valve 22, 23 from seat 24 but no fuel flow into the delivery line occurs until portion 25 of said valve stem clears the upper edge of adapter I2. The initial upward movement of the valve eliminates any voids in the delivery line and mechanically compresses any trapped gases, thereby placing the fuel in said delivery line under asuitable pressure. When retraction collar 25 moves out of the bore of adapter I2, fuel is introduced into the delivery line from the pressure chamber and delivery 'continues until helices 30 and 33 overlap ports I9l and 44, respectively. Fuel is then by-passed through passages'3l and 32 and port I9 to the supply line and the fuel pressure in cylinder II drops to the supply line pressure, permitting spring 21 to cause valve 22, 23 to move downward into closed position. 'I'he pressure in the delivery line is relieved by the downward movement of said valve and by the flow of fuel through the system of relief passages connecting passage 34 to port 44 and thence across plunger I4, through port I9 to the fuel supply line. The relief passage system from passage 34 to port 44 acts not only to relieve the pressure in the delivery line but substantially eliminates or effectively damps the pressure surges which normally occur upon the lclosing of the delivery valve. This is of utmost importance, particularly with a nozzle of the 'open type or one adapted to operate at rela` tively low fuel injection pressures, since it prevents any dribbling of fuel into the engine cylinder after the cut-off point. It is to be noted that the relief passages are connected to the fuel supply line during portions of the upstroke and the downstroke 0f the pump plunger, i. e., during the period that helices 30 and 33 are in communication with ports I9 and 44, so that there is a suilcient opportunity for elimination of pressure surfaces. When the by-pass port is closed to the pressure chamber, i. e., during the suction part of the downstroke, the relief passages are lalso cut o. from both the supply line and the pressure chamber. yAs a result, the suction set up in the pressure chamber during this portion of the downstroke does not affect the delivery line pressure. The relief of the delivery line 'pressure in this manner without the creation therein of suction pressures materially increases the efficiency of the fuel delivery, particularly when the engine is operating at high speeds.

Central passage 3| may be eliminated if the pump is to be utilized with a differential pressure type nozzle, in which event, after the fuel injection cut-olf, i. e., after helices 30 and 33 overlap ports I9 and 44, the fuel is by-passed from the pump pressure chamber through channel 39, passages 42 and 43, port 44, and across the pump plunger t0 port I9 and the supply line. The valve 22 remains lifted from its seat 24 during this by-pass portion of the stroke.

Another embodiment of the invention is illustrated in Fig. 2 and the structure thereof, except for the delivery valve and the diameter of the adapter bore, is substantially similar to the above-#described embodiment. Accordingly, like parts of the two embodiments or parts thereof which differ only dimensionally are designated by like numerals. The novel delivery valve 45, shown in Fig. 2, is slidably mounted in the vbore of adapter |2 and when in closed position the lower end of said valve seats on shoulder 24 to form a Huid-tight seal. When valve 45 is raised, groove 39 communicates with the pressure chamber and the latter is, in turn, connected through a suitable fluid passageway in said valve to the delivery line. As shown, said passageway comprises a central axial recess 46 extending from the upper end of said valve to a point adjacent the lower end thereof and a plurality of radial passages 41 which` connect with said recess at one end and open into groove 39 at the other end.

In operation, when plunger I4 covers inlet port I6 on the upstroke to begin fuel pumping, valve 45 is raised and connects the pressure chamber to groove 39 and, therefore,'to the delivery line Which is in continuous communication with said groove through passages 46, 41. Fuel delivery then takes place until, at a later point in the plunger upstroke, helices 30 and 33 overlap ports I9 and 44, and thereby connect the pressurey chamber and groove 39 to the supply line through passage 3! and passages 42 and 43,"'respectively,`

3| is eliminated as pointed out above. When the pump plunger reaches its point of by-pass or its top dead center position, depending upon whether or not there is a passage 3l in the plunger, spring 21 closes valve Il, which seats on shoulder 2l, but ,the delivery line remains connected to the supply line through recess 46, radial passages 41 and the fuel passageway 42, 43 from groove 39 to port M. Accordingly, the pressure in the delivery line is relieved across the pump plunger. However, as in the preceding embodiment, the delivery line is not subjected to the suction created in the pressure chamber during the piston downstroke because the relief port 44 is disconnected from said chamber concurrently with by-pass port i9. I

'Ihere is thus provided novel fuel injection apparatus wherein the fuel in the delivery space between a pump and an injection nozzle is maintained at substantially the same pressure as the supply line, except during the effective portion cf the pump stroke when fuel is being delivered io the nozzle. Novel means permit relief of the pressure in the delivery line after each injection of fuel into the engine cylinder so as to substantially eliminate dribbling from the fuel nozzle without introducing air pockets or producing undue suction in the line. There is additionally provided a novel delivery line pressure relief sys :em wherein valve means act to obviate pressure surges in the line. As a result, the novel pump means is extremely effective for injecting fuel to nozzles adapted to function at low injection pressures, particularly nozzles of the open type. Moreover, at high speed operation, the novel structure of the instant invention acts to increase the volumetric eillciency of the fuel delivery pump.

Although only two embodiments of the present invention have been illustrated and described, it is to be expressly understood that the same is not limited thereto.- For example, vari- .ous changes may be made inthe design and arrangement of parts illustrated without departing' .from the spirit and scope of the invention, as will now be apparent to those skilled in the art. For a definition of the limits of the .,invention, reference is had primarily to the appended claims.

What is claimed is:

l. In a fuel injection pump, means comprising a pressure chamber and including a plunger, said plunger operating. as a bypass valve to connect said chamber to the fuel supply line during a predetermined portion of the stroke thereof, a delivery valve controlling the fuel flow from said chamber to a delivery line, and means constituting a relief passageway for connecting the delivery line to a fuel supply line during the entire by-pass portiony of the piston stroke, said lastnamed means comprising passages through said delivery valve and said plunger.

2. In a fuel injection pump, means comprising a pressure chamber and including a plunger, a deliveryvalve controlling the fuel flow from said chamber to the delivery line, and means ,constitting a relief passageway connecting with the delivery line, said plunger having passages therein adapted to concurrently connect said pressure chamber and said passageway to a region of relatively low pressure, such as a fuel supply line, during a predetermined portion of said plunger stroke, the connection between said chamber and said low pressure region being independent of said passageway. g

.valve connecting with the delivery line, andv 3. In a fuel injection pump, means comprising a pressure chamber and including a plunger,la

'delivery valve controlling the fuel ilow from said chamber to a delivery line, and means constituting a relief passageway connecting with the delivery line when said valve is closed, said plunger acting as a valve to concurrently connect said pressure chamberand said passageway to a reion of low pressure, such as a fuel supply line, the connection between said chamber and said low pressure region being independent of said passageway.

4. In apparatus of the class described, a cylinder having a by-pass port, a relief port and an inlet port, said by-pass and inlet ports connecting with a fluid supply line, a piston reciprocably mounted in said cylinder, an adapter mounted adjacent one end of said cylinder to form a pressure chamber with said piston and cylinder, a delivery valve carried by said adapter to control the fluid flow from said chamber to a delivery line, said valve havingJluid-tight engagement with said adapter'when in closed position, means comprising a relief passage from said relief port to a port in said adapter, thelatter port communicating at all times with a passage in said check valve means in said last-named passage permitting iluid to ilow from said delivery line to said relief port, said piston connecting said relief port and said pressure chamber to the supply line during a predetermined portion of the stroke thereof.

5. In apparatus of 'the class described, a cylinder having an inlet port, a by-pass port and a relief port, said by-pass port and inlet port connecting with a fuel supply line, a piston slidably mounted in said cylinder, an adapter mounted 'adjacent one end of said cylinder to form a pres- 40 sure chamber with said piston and cylinder, a

delivery valve slldably mounted in the bore of said adapter to control the fuel iiow from said chamber to a delivery line, said valve having a passage therein in constant communication with the delivery line and with a groove in said adapter. bore, said groove connecting with said pressure chamber when said valve is in open position to deliver fuel through said valve passage, and means comprising a relief passage from said groove to said relief port, said port being connected by said piston to the fuel supply line during fuel by-pass.

6. In apparatus of the class described, a cylinder having an inlet port, a by-pass port and a relief port, said' by-pass port and inlet port connecting with a fuel supply line, a piston slidably mounted in said cylinder, an adapter mounted adjacent one end of said` cylinder to form a pressure chamber with said piston and cylinder, said piston operating as a valve to control the Aflow of fuel between said chamber and said inlet and by-pass ports, a pressure-actuated delivery valve slidably mounted in the bore of said adapter to control the fuel flow from said chamber to a delivery line, said valve having an open passage therein connecting said delivery line with a groove in said adapter bore, said groove connecting with said pressure chamber when said valve is in open position, and means comprising a relief passage from said groove to said relief port, the latter being connected by said piston to said by-pass port during'fuel bypass.

'7. Ina fuel pump having a pressure chamber and an adapter, a delivery valve slida'bly mounted a relief passage in said valve communicating at v one end with the delivery line land at the other end with a relief passage in said adapter through said radially extending passage, and a checkvalve in said first-named relief passage operaiive to prevent fuel flow in the direction of the delivery line.

8. In fuel injection' apparatus, a plunger pump I adapted to receive liquid fuel from a supply line and deliver the same under pressure to a delivery line, and means having passages controlled by the pump plunger for connecting said delivery and supply lines to each other during a predetermined portion of the stroke of s aid plunger and including other passages for connecting the pressure chamber of said pump to said supply line during said portion of the plunger stroke independently of the position of said delivery valve. 9. In fuel injection apparatus, a plunger pump adapted to receive liquid fuel from a supply line and deliver the same under pressure to a delivery line, a delivery valve for controlling the connection between said pump and said delivery line, and means including a fuel passage in said delivery valve for connecting said delivery and supply lines to each other, the ow of fuel from the delivery line'to the supply line being controlled by the plunger of said pump. f

10. In fuel injection apparatus, a plunger pump adapted to receive fuel from a supply line and deliver the same under pressure to a deliv-v 13. In fuel injection apparatus, a fuel pump comprising a cylinder and a piston operable therein, said cylinder having port means through which the flow of fuel is controlled by said piston, a normally closed pressure operated delivery valve for controlling communication between the pressure chamber of said pump and a delivcry line, and means including a passage controlled by said piston for establishing communication between said delivery line and said port means and another passage for concurrently connecting said pressure' chamber with said port means immediately after the effective pumping `stroke of the plunger while said delivery valvey is in closed position.

14. In fuel injection apparatus, pump meansl comprising a cylinder and a piston operable `ltherein, said cylinder having port means in the wall thereof controlled by said piston and connected with a region of low pressure, such as a .source of fuel supply, means connecting the discharge side of said pump with a delivery line, a delivery valve for controlling flow through said connecting means, and means including a check valve controlled passage in said delivery valve and a passage controlled by said piston for establishing communication between said delivery line and said low pressure region independently of the pressure chamber of said pump means during at least a portion of the time that said delivery valve is in closed position.

15. In fuel injection apparatus, a plunger pump adapted to receive liquid fuel from a supply line and deliver the esame under pressure to a delivery line, a delivery valve for controlling flow of said fuel between said pump and delivery line, means including a passage controlled by the 40 cntly of the pressure chamber of said pump, durery line, normally closed delivery valve means I adapted to receive liquid fuel from a supply line and deliver the same to a delivery line under pressure, delivery valve means for controlling the connection between the pressure chamber of said pump and said delivery line, means including a passage in said valve means for connecting said delivery line with a relief port in the wall of the pump cylinder, and a one-way check-valve in said passage adapted to permit flow from said delivery line, said plunger being adapted to connect said relief port with said supply line during a predetermined portion of the stroke thereof.

l2. In fuel iniection apparatus, a fuel pump comprising a cylinder and a piston 'operable therein, said cylinder having inlet and by-pass ports controlled by said piston and connected to a source of fuel supply, the'discharge side of said pump being connected to a fuel delivery line, means controlling said connecting means including a resiliently closed delivery valve, and means including a passage in said valve and passages controlled bysaid plunger for connecting said delivery line to said source of fuel supply.

pump plunger for establishing communication between said delivery and supply lines independing a predetermined portion ofthe stroke of said plunger while said delivery valve is in closed po- `sition, and a one-way check-valve in said passage adapted to permit ow from said vdelivery line.

, 16. In fuel injection apparatus, a plunger pump adapted to receive liquid' fuel from a source of supply and deliver the same under pressure to a delivery line, valve means for controlling the flow of said fuel between said pump and delivery line, and means controlled by the pump plunger 4for establishing communication. between said delivery line and a region of low pressure independently of the pressure chamber of said pump during a predetermined portion of the stroke of said plunger while said valve means is in closed position, said communication establishing means including a one-way check-valve adapted to permit flow from said delivery line.

17. In a fuel injection pump, means including a reciprocable plunger forming a pressure c hamber adapted to be connected with a fuel supply line, a delivery valve controlling the flow of fuel from said chamber to a delivery line, said* plunger beingvoperable as a by-pass valve to connect said chamber to said supply line independently of said delivery valve during a predetermined portion of the pressure stroke of the plunger, and means constituting a relief passageway adapted to connect said delivery line to said supply line independently of said pressure chamber during said portion of the plunger stroke when said delivery valve is in closed position.

18. In a fuelinjection pump, means including ber adapted to be connected with a fuel supply line, a delivery valve controlling the ilow of fuel from said chamber to a delivery line, said plunger being operable as a by-pass valve toconnect said chamber to said supply line independently of said delivery valve during a predetermined portion of the pressure stroke thereof, and means constituting a relief passageway for connecting said delivery line to vntly of said pressure chamber while said chamber and supply line are in communication with each other through said by-pass connection.

19. In fuel iniection apparatus. a plunger pump adapted to receive liquid fuel from a supply line 'and deliver the same under pressure to a delivery line, valve means for controlling the connection between the pressure chamber of said said supply line independ-'l pump and said delivery line, and means including a passage controlled by the plunger of said pump for connecting said pressure chamber and 2o passage fo vwith a region of relatively low pressure. such as .said supply line, during'a predetermined portion of the stroke thereof, and a one-way check-valve in said passage adapted to permit now from said delivery line.

ALBERT T. BR.

immediately following the .closure said delivery line, means including a wall of thepump cylinder, saidl

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