US2430801A - Fuel injection apparatus - Google Patents

Description

Nov.v 11, 1947. Axr. BREMSFR YFUELy INJECTION APPARATUS Filed Sept. 16, 1942 FIG. l

ATToRrfulzbzv Patented Nov. 1l, 1947 aantrof FUEL INJEc'rToN ArrAn'rUs Albert T. Bremser. Sidney, N. Y., assigner to Benidix Aviation Corporation, New York, N. Y., a corporation of Delaware Application September 16, 1942, Serial No. 458.528

This invention relates to fuel injection apparatus and more particularly to means for controlling and effecting the delivery of fuel under pressure to the cylinders of a solid fuel injection engine.

One of the objects of the present invention is to provide a novel fuel injection apparatus whereby pilot injection, that is the injection of a small charge of fuel just prior to the injection of the main charge to edect more eflicient burning of the latter, is efliciently achieved.

l Another object is to provide a novel fuel injection unit embodying a fuel pump and injection nozzle in a unitary structure.

A further object is to provide a novel fuel pump for obtaining pilotand main injections, which pump embodies only a single pumping member or plunger.

A. still further object is to provide a fuel injecl tion pump having a novel plunger and cylinder arrangement for effecting pilot and main injections in a definite predetermined relation to each other.

Still another object is to provide novel apparatus of the above character which is extremely compact and wherein both pilot and main injections take place successively during a continuous movement of the plunger in one direction.

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 yacecn'npanying drawings. it is to be expressly understood, how- 14 claims. (ci. 10s- 41) '2 housing l2 having a ange I3 formed intermediate the ends thereof and secured to cylinder head Ill by bolts i4 so that the lower end of said housing extends into recess II. A nozzle holder body l5 having an external shoulder i'l formed at the upper end thereof is mounted in the lower end of housing i2 and is secured in operativeposition by a gland nut it which screws into said housing and cooperates with said shoulder, a gasket it being preferably interposed between said shoulder and said gland nut. The latter is effective to hold-nozzle body i5 in abutting sealing engagement with the lower end of a. fuel pump cylinder 3l to be hereafter described.

Threaded on the lower end of body l5 is a'sleeve nut it which is provided at its lower end with an internal shoulder it for supporting engagement with the flanged upper end tia of a nozzle tip ill, said nozzle having a central bore or duct 2lb therein and a plurality of vradially extending orifices tic adjacent the lower end or tip thereof. The nozzle tip 2li projects into the combustion chamber of the engine cylinder so that fuel can be sprayed from oriiices itc into said chamber chamber. n liner'ii constitutes a portion of the ever, that the drawings are for the purpose of f illustration only and are not intended as a definition of the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

ln the drawings, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a sectional elevation view, with parts broken away, of one type of unit or uni-flow fuel injector embodying the present invention; and

Fig. 2 is a fragmentary viewl ofa modification of the plunger and cylinder arrangement of th above injector.

Referring to Fig, 1, the present invention is shown embodied in a unit injector, i. e., a unitary structure wherein a fuel pump and fuel injection nozzle are combined. Said injector is operatively positioned in the head it of a cylinder of a solid fuel injection engine, said cylinder head having a recess li therein for receiving said injector. The latter preferably comprises a main barrel or wall of recess i i where the latter extends through the cooling chamber ln cylinder head it, said liner surrounding sleeve it and being supported at its lower end by internal shoulder it.

Removably mounted in nut iii above nozzle tip it is a valve guide it that is centrallybored for slidably receiving the stem or piston portion of a needle valve 2l. The bore through said guide member terminates at the lower or inner end of the latter in a small orifice 2da which is coaxial with passage iib, and a conical seat 2Gb is provided adjacent said orifice for cooperation with the tapered lower end of needle valve 2l. The latter is thus effective to control the flow of lfuel from member 2t into duct 2lb and hence into the engine cylinder. Preferably, the lbore in member 26 is enlarged immediately above valve seat "2Gb to provide a fuel pressure chamber 28 through which a reduced portion of valve 21 extends. Fuel supplied under pressure to chamber 28 through a suitable passage 29 in member 26 in a novel manner hereinafter described acts against the shoulder formed on the valve by the reduQtiQn. in the diameter thereof, and is thus `more fully described hereinafter.

3 effective to lift the latter off its seat and permit the flow of fuel from said chamber through passages 26a, 2lb and 2Ic into the engine cylinder.

Valve 21 is normally held in seated or closed positionby suitable means comprising resilient means, such as a coil spring 30, which applies yielding pressure to the valve through a pressure pin or spindle 3i that freely extends through the central bore in body I5. The lower end of spindle or rod 3| is preferably recessed for freely receiving a pin 21a formed by a reduced portion at the upper end of valve 21. A collar 32 may be formed near the upper end of the valve spindle to serve as a seat for one end of spring 30. The other end of the spring engages the inner end of a plug nut or screw 33 which is threaded or otherwise suitably secured in the upper end of the bore in nozzlevbody I5. said bore being'of enlarged diameter at its upper end to receive spring 30 and said plug screw.

Between the adjacent ends of body I and valve member 26 there is preferably interposed a washer member or plate 34 having a central 35 extending from the upper end of body I5 connects with passage 29 in guide member 26 through an oriilce 36 in plate 34. The latter may be readily replaced if it becomes worn byl theconstant hammering of valve 21 thereagainst.

In order Ilto deliver fuel under pressure in a novel manner to chamber 28 and thence to the combustion chamber of the engine cylinder, novel pumping means are embodied in the injector unit. In the form illustrated, said means comprise a pump cylinder 31 mounted in the bore of housing I2 on the upper end of body I5 and having an external shoulder 38 thereon in engagement with a shoulder in said bore, whereby said cylinder is rigidly secured against axial movement by gland nut I6. Suitable means, such as. a set screw (not shown), may also be provided for holding said cylinder against rotary movement. One or more fuel inlet ports 39 ex tend radially through the wall of cylinder 31 adjacent the lower end thereof and connect with Tan internal annular groove 40 in housing I2 which, in turn, communicates with the fuel supply line through passages 4i. A pair of axially spaced by-pass or metering ports 42 and 43 are also provided in the Wall of cylinder 31 to connect the interior thereof with groove 40. There is mounted in the cylinder bore for reciprocating 42 and thereby7 vary the effective pumping stroke of the piston, suitable means for angularly ad*- justing plunger 44 are provided and, in the form shown, comprise a sleeve, 48 loosely surrounding the upper end of cylinder 31 in the enlarged interior of the upper end of housing I2. Gear teeth '49 are formed on the lower end of sleeve 48 for cooperation with a rack member (not shown) in a manner well-known in the art. The upper end of sleeve 48 is axially slotted at 53 for slida'bly receiving a cross bar 5I rigidly connectedto plunger 44. Sleeve 48 seats on an internal shoulder 53 in housing I2 and is held against axial movement relativeI to cylinder 31 by a ring member 52 which engages an external shoulder on said sleeve and is positioned against an internal shoulder 53a in housing I2, said ring member being held on the latter shoulder` by a spring 54 which constitutes an element of the plunger reciprocating means. The latter comprises a tappet cup 55 which is slldably positioned in the upper end of housing I2 for engagement with an enlarged head portion 56a of a member 56 operatively connectedtoaoretn` tegrally formed with the upper end of piston 44. The latter may be moved downwardly by a cam actuated tappet lever (not shown) or other suitable means which is adapted to engage the closed end of tappet cup 29 in a manner well understood in the art. The downward movement of said plunger is.. resisted and the upward movement thereof is effected by spring 54 which has thelower end thereof seated on ring member 52 I' and the upper end thereof engaging a washer movement therein a plunger 44 cooperating with said inlet and by-pass ports as a slide valve to ycontrol the flow of fuel therethroughin a manner A pressure chamber is thus formed in cylinder 31 between the lower end of plunger 44 and the upper plugged end of nozzle `body I5 and fuel conducting passage 35 opens into said chamber. By providing a passage 4I on each side of the pump, one of which communicates with a sump, a continuous circulation of fuel may be maintained through annular chamber 40 for cooling the pump.

To control the point of main fuel by-pass, i. e., the termination of main fuel injection, a helical groove 45 is provided in the surface of plunger 44 for cooperation, in a manner well understood in the art with 'by-pass port 42, said groove being continuously connected to the pressure chamber of the pump by suitable passages, such as con- 51, which, in turn, engages a downwardly facing shoulder formed by the enlargement of head 56a to transmit upward forces to plunger 44.

Novel means are provided for effecting a primary or pilot fuel injection into the combustion chamber of the engine cylinder in a predetermined time relation to the main fuel injection during a continuous down or power stroke of plunger 44. In the form illustrated, said means comprise a by-pass or relief passage 58 provided in cylinder` 31, which passage is connected at its lower end with the pressure chamber of the pump and at the upper end thereof with a port 58a which opens into the bore of said cylinder. An axially extendingA groove 59 is provided in the surface of plunger 44 and is adapted to overlap the upper end of passage 58 at a predeter- V ,mln'cdpoint in the plunger stroke to `thereby "connect said passage with an annular peripheral groove 60 in said plunger. Pilot by-pass port 43 in cylinder 31' is axially spaced above main bypass port v42 and is adapted to connect groove 60 to inlet channel 40 for a predetermined part ol the plunger stroke.

To prevent the trapping of fuel which leaks past valve 21 to the upper end of the bore of nozzle body i5, a relief passage 6I is provided between said bore and groove 40.

In operation, when plunger 54 is at top dead center position prior to the down or power stroke thereof, the pump pressure chamber and the fuel conducting passages 35, 29, 28 are filled with fuel at supply line pressure, port 39 is open and port 58a is closed. When plunger 44 moves downward to close inlet port 39 the pressure of the fuel in the pressure chamber is built up after closure of said port and is transmitted to chamber 28, raising valve 21 and thereby permitting 7 being rendered operative upon the overlapping of one of said passages and said passage means during the plunger power stroke after the beginning of effective pumping to by-pass fuel from said chamber and thereby interrupt the eile'ctlve pumping of said plunger, said plunger thereafter disconnecting said passage means from the other of said passages during the power stroke to effect a resumption of eiective pumping.

4. In a fuel pump of the type comprising a cylinder, a plunger mounted for reciprocation in said cylinder and means constituting a main system for by-passing fuel from said cylinder,'the combination. therewith of means comprising passages in said plunger and said cylinder constituting a primary by-pass system for interrupting the effective pumping during the plunger power stroke to control the duration of a pilot delivery and the timing of the main delivery of fuel from the cylinder, the opening of 'said system being determined by the cooperation of said plunger and one passage in said cylinder and the closing of said system being effected by the closing of another passage in said cylinder by said plunger.

5. In a fuel injection pump having a compression chamber comprising a cylinder and a plunger, means for interrupting the pumping during the power stroke of the plunger to terminate e. pilot injection; said means comprising a bypass port in said cylinder, a passage in said plunger and a passage in.said cylinder communieating with the compression chamber, said plunger passage overlapping said cylinder passage to connect said compression chamber to said by-pass port to begin by-pass and said plunger passage being adapted to move out of overlapping relation vwith said by-pass port to terminate bypass and effect the beginning of main injection.

5. In a fuel injection pump having a pressure chamber comprising a cylinder and a plunger, means for interrupting the pumping during the power stroke of the plunger to terminate .pilot injection, said means comprising a by-pass port in said cylinder, a passage in said plunger and a passage in said cylinder in continuous communication with said pressure chamber, said plunger passage overlapping said cylinder passage to begin by-pass and moving out of overlapping relation with said port to terminate by-pass.

' 7. In a unit injector, a fluid pressure pump and a nozzle rigidly connected together to form a rigid unit, said pump including a cylinder and a plunger slidably mounted in said cylinder to dene a pressure chamber, means including a pressure responsive valve connecting said chamber to said nozzle, and means comprising a plurality of passages in said plunger and ports in said cylinder for successively effecting pilot and main fuel deliveries from said chamber to said nozzle during each power stroke of said plunger.

8. In a unit injector, a cylinder, a plunger slidably mounted in said cylinder to degne a pressure chamber, a nozzle, means connecting said nozzle means including a passage in said plunger and a port in said cylinder which are disconnected by the plunger movement to terminate fuel by-pass, and means for eecting a second by-pass of fuel to terminate the main injection.

10. In a fuel pump, means comprising a pressure chamber, said means including a cylinder and a plunger reciprocable in said cylinder, means comprising a port in said cylinder, a passage in said plunger adapted to communicate with said port and a passage in said cylinder adapted to connect said plunger passage with said chamber for effecting a first fuel by-pass from said chamber during the plunger power stroke to terminate a rst fuel delivery from said chamber, and means comprising a port in said cylinder and a passage in said plungerfor effecting a second by-pass of the fuel from said chamber during the same plunger power stroke to terminate a second fuel delivery from said chamber.

1l. In pumping apparatus for delivering a liquid under pressure to a delivery line, means forming a pressure chamber including a cylinder and aplunger reciprocable therein, an inlet port in said cylinder adapted to be covered by said plunger for determining the beginning of the delivery of liquid to said line, and cooperating passages formed in and by said cylinder and plunger for effecting two deliveries of liquid to said line during. one continuous 'power stroke of the plunger, certain of said passages cooperating to determine the termination of'the first deliveryand others of said passages cooperating to determine the initiation of the second delivery.

12. In pumping apparatus fondelivering a liquid under pressure to a delivery line, means forming a pressure chamber including a cylinder and a plunger reciprocable therein and cooperating ports and passages formed in and by said cylinderl and plunger for effecting a temporary by-pass of liquid from said chamber to interrupt the delivery of liquid to said line for an interval during an intermediate part of each pumping stroke of said.

plunger, the beginning of said interval being determined by the movement of certain of said ports and passages into overlapping relation and the termination of said interval being determined by the movement of others of said ports and pas-r sages out of overlapping relation.

13. In apparatus of the class described, means forming a pressure chamber including a cylinder and a plunger reciprocally mounted therein, and cooperating passages formed in and by said cylinder and plunger for effecting two delivere; of a liquid from said chamber to a delivery line during each pumping stroke of said plunger, the termination of the rst delivery being determined by movement of a passage inthe plunger into overlapping relation with a passage in said cylinder and the beginning of the second delivery being determined by movement of said passage in the plunger out of overlapping relation with a different passage in said cylinder, at least one of said passages having continuous communication with said pressure chamber and at least one other of said passages being in continuous communication with a region of low pressure.

14. vIn pumping apparatus for delivering a lq- 5 uid under pressure to a delivery line, means forming a pressure chamber, said means including a cylinder and a plunger reciprocable therein, said plunger and cylinder cooperating to effect two deliveries of liquid from said chamber to said line during each pumping stroke of said plunger, the interval between said deliveries being determined by the opening of one passage in the cylinder by movement of the plunger and the subsequent closing of another passage in the cylinder by movement of said plunger, one of said passages having communication with said chamber and the other of said passages having communication with -a region of relatively low pressure.

' ALBERT T. BREMSER.

REFERENCES CITED The following references are of recom" in the me ef this patent:

UNITED STATES PATENTS Number Name Date 2,173,813 Bischof Sept. 19, 1939 1,993,759 Stockmeyer Marl i2, 1935 1,951,215 Sidney Ma. 1.934 2,306,364 Skaredoff Dec. 2i, 1942 FOREIGN PATENTS Number Country Date 375,151 Great Britain 1932 572,711 Germany 1933 679,312 France 1920

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