US1868713A - Fuel injection system - Google Patents

Description

July 26, 1932. s, MlLLER 1,868,713

FUEL INJECTION SYSTEM Filed Nov. 18, 1929 isheets-sheet 1 INVENTOR 574M157 D MILLER ATFORNEY July 26, 1932.

S. D. MILLER FUEL INJECTION SYSTEM Filed Nov. 18, 1929 s Sheets-Sheet 2 t q ATTORNEY July 26, 1932. 1 NHLLER 1,868,713

FUEL INJECTION SYSTEM Filed Nov. 18, 1929 3 Sheets-Sheet 3 INVENTOR jmA/L KY 0, M/L 1.5;?

BY W q/ WWW ORNEY V Patented July 26, 1932 UNITED STATES STANLEY D. MILLER, OF ALAMEDA, CALIFORNIA.

FUEL INJECTION SYSTEM Application filed November 18, 1929. Serial No. 407,827;

This invention relates to improvements in fule injectors for internal combustion engines, and it has reference in particular to devices of that character designed for use with Diesel, or other types of'internal combustion' engines using heaving oil for fuel.

The principal objects of the present invention are: first, to provide for an accurate measurement of fuel charges and their delivery in a properly atomized condition especially at high engine speed; second, to provide meansfor overcoming what is known as afterdrip at the spray nozzle; third, to provide a pump, or supercharger, in connection with the injector for delivering the fuel oil to the measuring chamber under high pressure; fourth, to avoid use of spring controlled check valves andto prevent leakage, or back flow, under pressure of the injecting piston by use of a positively acting valve piston; fifth, to provide for regulating the pressure at which the fuel is delivered to the injector and means for regulating or varying the amount of the injected charges; sixth, to provide a straight line flow of oil; that'is, no back flow in the feed line incident to injection. 1

Other objects of the invention reside in the various details of construction and in the combination of parts, and in their mode of operation as will hereinafter be described.

In accomplishing these objects, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein Fig. l is an, end elevation of'an engine equipped with a fuel injector in accordance with the present invention; the engine being show-n partly in section for better illustration.

Fig. 2 is an enlarged, face view of the injector.

Fig. 3 is a sectional view, taken on line 3-3 in Fig. 2, showing the driving connections provided between the crank shaft of the engine and the camshaft of the injector, also showing the driving connection betwe n the cam shaft and fuel pump, or super; charger.

Fig 4 is a side elevation of the injector;

parts'being broken away for better illustration.

Fig. 5 is a vertical section taken substantially on the line 5-5 in Figure 4.

Fig. 6 is an enlarged sectional detail of a part of the injector mechanism.

Fig. 7 is a sectional detail of the spray nozzle.

Fig. 8 is an enlarged view showing the relationship of the cams for actuating the fuel, injection piston and the valve piston.

Referring more in detail to the several views of the drawings The fuel injector embodied by the present invention, is shown in Figure 1 in its operative connection with a certain well known type of Diesel engine that operates on tue two stroke cycle principle. It is to be understood, however, that the particular make, or type of engine, is immaterial andthat whether it operates on the two stroke or on the four stroke cycle principle is material only in so far as it concerns the use of proper gearing, or other means, for timing the action of the injector with respect to the movement of the piston of the engine. Furthermore, it is to be understood that the present fuelinjection device is not to be confined in its use to Diesel engines, but is adaptable to various other types of internal combustion engines ;.it having been here shown, and will be describedin connection with a Diesel engine for the reason that its use, apparently, for the greater part, will be in connection with such engines.

Referring to Figure 1, l designates the cylinder of the engine, 2 a piston that is reciprocable therein and which is connected by a rod 3 with a crank shaft 4 in the usual manner. The crank shaft is revolubly mounted in the crank case 5, and this is'supplorted in a base 6 to whichit is secured by suitable means, such as the bolts 7. At one side of the crank case is an opening 8 equipped with an air valve 8a, and leading upwardly from the crank case is a channel 9 that opens into the cylinder 2 through a port 10. An exhaust port 12 opens from the cylinder directly opposite the port 10 and both of these are uncovered by the piston when it reaches the bottom of its stroke. A head 15 closes the upper end of the cylinder and this has a fuel injection nozzle 16 mounted therein; fuel oil ence numeral 20.

In the above type of engine, as the piston 2 travels on its upward stroke, air is drawn into the crank case past the valve 8a, and at the same time, air is being compressed in the upper end of the cylinder. When the piston reaches the upper end of its upward stroke, the air in the cylinder has been compressed. Fuel is then injected into the hot compressed air from the spray nozzle 16, and combustion occurs, driving the piston on its down stroke. During the downard stroke, the air in the crank caseis compressed and as the piston nears the end of this stroke, the exhaust port 12 is uncovered and this is followed by uncovering of the port 10. The burned gasses escape through the exhaust port and the compressed air entering from the crank case completes the scavenging and furnishes the cylinder with air for the next compression stroke.

The present injector 20 is timed in its operation by connection with the crank shaft of the engine as is shown in Figure 3. wherein, 21 designates a gear that is keyed on the end of the shaft 4 and 22 is a gear that meshes therewith and which is fixed on one end of a cam shaft 23 embodied in the injector mechanism. The gears 21 and 22, designed for an engine operatin on the two stroke cycle principle, WOIIldfiJB of equal diameter so that the cam shaft would rotate at the same rate as the crank shaft. For a four stroke cycle engine the gear 21 would be one-half the diameter of gear 22 and cam shaft 23 would then rotate at one-half the crank shaft speed.

The present injection mechanism,'as best shown in Figures 4 and 5, comprises a housing or frame including a base plate 25 by which it may bemounted and to which are secured spaced, upright walls 26 and 27. The cam shaft 23-extends through suitable bearings, as at 28 and 28' in the walls 26 and 27, respectively, and at its end, opposite that on which gear 22 is fixed, is keyed a gear 29 meshing with the driving gear 30 of a fuel pump, or supercharger, 31. As here shown, the pum is fixedly mounted on the base plate 25, and as an inlet connection 32 at one side with which a fuel oil supply pipe 33 connects,

and at the other side has aconnection 34 from which a discharge pipe 35 leads. This pump may be of any suitable character capable of delivering the fuel oil under high pressure into the pipe 35 for delivery to the measuring and injecting devices presently described in detail.

While the pipe 35 might in some instances lead directly to the injector mechanism, it is preferred that it be connected to a pressure control valve of any suitable type, such as at 37, for regulating the pressure of injection, and which is connected with an oil strainer as at 38; the oil strainer in turn being connected by a pipe 39 throu h a back check valve 40 with a port 41, as inl igure 5, leading into the measuring and injecting devices. The arrangement is such that, operation of the pump causes oil to be delivered under high pressure through the pipe 35 to the pressure control valve, from which it passes at a constant pressure through the strainer 38, thence through the pipe 39 and valve 40 to the measuring and injecting means.

Fixed between the spaced walls 26 and 27 in the upper portion of the frame of the injector mechanism is a block provided with parallel, vertical bores 46 and 47 within which are fitted the cylinders 48 and 49 for an injecting and measuring piston 50 and a piston valve 51, respectively. The bore 46 enters from the lower face of the block and is enlarged at its lower end for admittance of an annular shoulder 48' on the cylinders 48. A collar 52 is threaded into the enlarged end of the bore against the shoulder to retain the cylinder tightly seated. The piston 50 is slidably mounted in the cylinder 48 and it extends from the lower end of the cylinder where it is provided with a flat head 55 upon which a spring seat 56. is mounted. A coiled spring 57 encloses the lower end of the piston and cylinder and bears at its ends against the base of the block 45 and against the ring seat to urge the piston downward y.

The head 55 at the lower end of the piston rests upon the upper end of a slide 58 that is axially alined with the piston directly over the cam shaft, and is slidably contained in a bushing 58 threaded through a horizontal wall 59 overlying the cam shaft. The lower end of the slide 58 bears against the upper surface of an actuating lever 60 which extends across the cam shaft with one end pivotally mounted on a supporting pin 61 so that its opposite end portion, against which the slide rests, may move upwardly and downwardly within a plane that is perpendicular with respect to the axial line of the cam shaft. Directly underlying the lever 60 isa rocker 62 pivotally supported at one end by a supporting pin 63 and having a roller 64 mounted at its other end for rolhng contact with a cam 65, presently described in detail, that is keyed on the cam shaft 23.

The lever 60 and rocker 62 have their pivot points at opposite sides of the vertical plane of the cam shaft and the lever 60 is actuated by the rocker through the mediacy of the rounded head portion 66 at one end of a link 67 that is disposed between them, as in Figure 5. The outer end of the link has pivotal connection, as at 68, with an arm 69 fixed on a cross shaft 70 that is revolubly mounted in the side walls of the frame and provided at its outer end with an adjusting lever 71.

It'is quite apparent that, as the cam 65 revolves, the follower 62 will be actuated upwardly and downwardly accordingly. Thus, through the head 66 of link 67, lever 60 and slide 58, the injecting and measuring piston 50 will be actuated upwardly to be returned by the pressure of coiled sprin 57. It is also apparent that the length 0 the stroke of piston 50 may be varied to a more or less extent by adjustment of the link 67 which will cause its head portion 66 to be moved from or toward the swinging end of the link 60; the nearer to the end 1t is. adjusted, the shorter will be the stroke of the piston.

As a mechanical feature, the adjacent faces of the lever 60 and rocker 62 on which the head 66 slides, are grooved to provide guideways for the head, also, for the purpose of retaining an adjustment of the link made by movement of the lever 71, the latter is made to follow on an arcuate guide bar 75 that.

is fixed to the frame,and a set screw 76 is threaded into the handle portion of the lever and is adapted to be tightened against the arcuate bar to retain the lever at a set position. It is intended that the lever 71 be operatively connected with the governor of the engine usually employed so that an adjustment whereby the fuel charge is made more or less will be in accordance with faster or slower speed of the engine.

The cylinder 49 for the piston valve 51 enters from the top of the block '45, and the bore of the cylinder block is provided with a plurality of upwardly facing shoulders, as at 77, against which the cylinder is seated.

A collar 77 is threaded into the upper end of the bore against an annular flange 78 on the cylinder to hold it seated, and the feed pipe 17 leads from the upper end of this cylinder to the fuel injection nozzle 16 in the engine head, as shown in Figure 1.

The lower end of the piston valve 51 slidable in cylinder 49 is provided with a head 80 on which a spring seat 81 is mounted, and a coiled spring 82 encloses the lower end of the cylinder and bears at its ends against the block 45 and the seat 81 to urge the piston downwardly against the upper end of a slide 84 that is alined therewith, and which is slidablewithin a bushing 85 mounted in the wall 59, with its lower end bearing against a rocker lever 86.

The lever 86 extends transversely across the cam shaft'23 and is pivotally mounted on the pin 63 parallel with and adjacent the rocker 62. The outer, orswinging end of the lever 86 engages with the lower end of slide 84 and it is equipped, directly above the cam shaft, with a roller 88 adapted for rolling engagement ona cam 89 fixed on the cam shaft' 23 adjacent the cam 65. In operation, rotation of the cam 89 causes an upward and downward rocking of the lever 86 and a corresponding action of the piston valve 51 which controls both the adm.ttance of fuel charges to the measuring chamber and injector, and also the delivery to the nozzle 16, as will now be described.

Formed aboutthe upper portion of the cylinder 49 just below the flange 78, is an encircling channel or groove 90 from which a plurality of channels 91 lead radially inward into the cylinder at a point across which the upper end of the piston 51 extends. This channel 90 communicates, at one side with a passage 93 which opens into a chamber 94 communicating directly with the upper end of cylinder 48. A channel 95 leads from the passage 93 downwardly within the block and then turns laterally into an annular channel 96 which encircles the lower end portion of the cylinder 49 and from which a plurality of passages 97 lead radially inward into the cylinder. S aced above the channel 96 is a channel,98 whlch encircles the cylinder and which is in direct communication withthe port 41 from the feed pipe 39. A plurality of ports or passages 99 lead from this channel directly into the cylinder 45.

When the valve piston 51 is at the lower position of its stroke, a connection is provided between the several passages 99, and the passages 97, through' an annular by-pass 100 provided by reducing in diameter a short length of the piston. When the piston 51 moves to the upper end of its stroke it incidentally closes off the connection and tightly seals the ports 97 against any back flow from the channel 95 under pressure of injection. Leading downwardly within the upper end of the piston 51, is a bore 102 whcih, at its lower end, has a plurality of downwardly and radially directed ports 103 opening into an annular channel 104 encircling the piston,

and this channel is brought into registration gradually diminishes during the next one hundred five degrees to a shorter radius which continues at the same curvature back to the lower end of the rise 65a. The cam 89 has a rise that extends at an even curvature through approximately twenty degrees.

device would be as follows: Rotation of the crank shaft 4 of the engine, through the gears 21 and 22 causes rotation of the cam shaft 23, and this in turn, through the gears 29 and 30, causes operation of the pump 31 to deliver fuel at high pressure through the pipe 35, the pressure control valve 37, the strainer 38 and pipe 39, past the back check valve 40 and finally into the cylinder 49. Assuming the valve piston 51 to be in its lowered position, as in Figure 6, and assuming also that the piston 50 at that time is in active and in its lowered position, a charge of oil will be delivered through the by-pass 100 in the piston 51, through the ports 97, channels 96 and 93 and into the socket 94 at the upper end of the cylinder 48; then as the cam shaft continues to rotate, the rise of cam 89 rocks the lever 86 upwardly and causes the piston 51 to be raised to the position shown in Figure 5 at which it cuts off further admittance of fuel and prevents back flow. This movement also brings the channel 104 at its upper end into registration with the connecting passage 93 with the upper end of the cylinder 48. Immediately following this movement of. the piston 51 to its up per limit of travel and while it remains in this position, the rise of the cam 65 effects a quick upward movement of the piston 50 and this effects the injection of the measured charge previously admitted, through the upper end passages of the piston valve 50 and cylinder 49 and into the pipe 17 and from the nozzle 16 into the engine cylinder.

1 Immediately following the injection stroke of the piston 50, there is a, quick downward,

or suction stroke of the valve piston 51 caused by the receding movement of the cam 89 and this incident to the initial movement of the piston 51 cuts off communication between the pump cylinder and delivery line to the engine and by a farther movement effects a reduction of pressure in the delivery line 17 which positively prevents any afterdrip at the nozzle orifice caused from the slowing up of the injection velocity or any leak at the seat in the injection valve. This feature is of prime importance as it prevents carbonization of the nozzle with its resultant difficulties.

As the piston 51 moves downwardly, it finally brings the passage 100 into position for the admittance of fuel to the measuring and injecting parts and thus a charge is forcibly delivered by the action of the super charging pump.

It is to be understood that the device can be easily adapted to engines operating 'on the four stroke cycle principle, simply by proper design of the cams and proper timing of the cam shaft with the engine.

It is to be understood also that changes might be made in the details of construction without departing from the spirit of the invention and for this reason it is not desired that the claims be limited only to the device as shown, but to cover it broadly commensurate with the invention.

Having thus described my invention, what I claim as new therein and desire to secure by Letters-Patent, is:

1. A fuel injector for engines of the character described adapted for'connection withv a fuel oil supply and having a delivery channel for connection with the engine, an injecting means operable to forcibly deliver fuel charges through said channel to the engine and a valve member operable by an initial movement to cut off communication between the delivery channel and injecting means and by a farther movement to effect back suction in the channel immediately following the cutting off of communication with the injecting means.

2. A fuel injector for engines of the character described having a delivery channel for connection with the engine, a cylinder having a connection for receiving charges from a fuel supply, a piston operable therein to forcibly deliver the charges received through saiddelivery channel to the engine, a second cylinder communicating with the delivery channel and a piston operable therein to cut off communication between said delivery channel and first mentioned cylinder and subsequently by'a farther movement to create back suction in said delivery channelimmediately following each injection operation.

3. A fuel injector for engines of the character described comprising a cylinder adapted to receive fuel charges from a fuel supp y a second cylinder having a delivery channe leading therefrom for connection with the engine cylinder and having a channel connection with the first cylinder, a piston op-' erable in the first cylinder to eject its charges to the engine through its connection with the second cylinder, a valve piston operable in the second cylinder, and means for actuating connection to the engine; said housing having a passage connected at one end with a fuel supply and leading through said valve cylinder to t-he measuring cylinder to supply the latter with fuel charges, a piston o erable in the measuring cylinder for the e ection of fuel charges to the engine through its channeled connection with the valve cyl-' inder, a valve piston in the valve cylinder and means for actuating the valve piston outwardly to uncover the outlet from the measuring cylinder for the injection of a charge, and for moving it inwardly after injection to cover the said outlet and to create back suction in the connection with the engine.

5. A fuel injector for engines of the character described comprising a housing, a valve cylinder in the housing having an outlet adapted for connection with the engine, a measuring cylinder having an injection passage leading into the first cylinder and communicating therethrough with the engine connection; said housing having a fuel delivery passage therein leading to said measuring cylinder and communicating through the valve cylinder with a fuel supply, a piston reci rocable in the measuring 0 linder for ejecting the charges received, a va ve piston reciprocable in the valve cylinder, means synchronized with movement of the first piston for actuating said valve piston to one position to close off connection of the fuel to create suction in the delivery con uit folv lowing each injection Priod. I Signed at Seattle, Evashington, this 8th day of October, 1929.

STANLEY D. MILLER.

delivery passage with the supply and to 0 en I communication between the measuring 0y inder and engine through the injection passage into the valve cylinder and for operating it to another position to close oif the injection passage and to open the fuel delivery passage.

8. In combination with an engine of the character described, a fuel injector nozzle associatedwith the engine 0 linder, an injector having a delivery con uit leading to said nozzle a cylinder having connection with a fuel supply device whereby fuel charges are delivered thereto under pressure, a. piston operable in the c linder to e'ect the fuel charges therefrom t rough sai delivery conduit and nozzle to the engine cylinder a second cylinder communicating with sai delivery ponduit and a piston operable therein by an initial movement to cut off communication between the delivery conduit and the first mentioned cylinder and by a farther movement to create back suction in the delivery conduit following each injection eriod. j

7. combination with an engine of the character described, a fuel injector nozzle 60 opening into the engine cylinder an injector device embodying a valve cylin er; a delivery conduit from said cylinder to said nozzle, a measuring cylinder havin an injection outlet communicating with said delivery conduit through the valve cylinder, and having

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