US1590244A - Fuel pump for internal-combustion engines - Google Patents

Description

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2 Sheets-Sheet 2 INVENTOR June 29 1926.

L..|L.LMER FUEL PUMP FOR INTERNAL coMBusTIoN ENGINES Filed Oct. 29, 1925 mb, yx. www E .o .sum dmv 0%". E www@ @mm \\Qmv N smv. mf w@ .w W. Q N MN. Nk NWN mum @QW v QQ* GR, H

Ns Po E@ @n QR, MH e@ Patented June 29, 1926.`

- UNITED STATES LOUIS ILLMER, OF CORTLAND, NEW YORK.

FUEL PUMP FOR INTERNAL-COMBUSTION ENGINES.

Application led ctober 29, 1925. Serial No. 65,642.

My invention relates particularly liquid fuel pumps for direct injection engines and closedl for the p u'rpose of cutting olf the fuel injection. While the engine is running, the

more especially such as serve multicylinder\\rail system is at all times maintained under oil engines. A primary object is to provide an engine accessory of this character that ,will maintain an exceptionally high velocity through a jet or spray nozzle regardless of the engine speed or load and without need i of compressed air for fuel injection purposes.

This object is in part attainedA by the use of an elastic impulsion drive for the pump plunger capable of accelerating the plunger at the time of fuel injection and serving to break up the liquid into a finely atomized state so as to allow of rapidly and perfectly mixing such pulverized fuel with all the available combustion air.

i A further object consists in devising pressure relief means whereby the initial fuel pressure behind such injection nozzlesmay be carried close up to the safe capacity of conventional high pressure feed lines under full load conditions and without having to exceed this pressure limit under partial engine loads. Furthermore, this im roved fuel pump may be operated upona xed stroke basis with a. gross delivery considerably in excess of act-ual engine fuel requirements, the surplus fuel being bypassed through said relief valve and indirectly regulated in accordance with the eective timing given to my injection nozzle control devices. l

The present disclosurespresent an improved mode of operation upon the type of impulsion pump set forth in my prior Patent No. 1,527,139 granted Feb. 17, 1925, and is distinguished therefrom in its broader aspects by the use of an intermediate rail line distributing system through which .fuel is delivered to the engine cylinders in a novel manner. In the present instance, the pump chamber is equipt 'with a dischargevalve of the conventional check type which delivers ino the receiving end of its rail line. The remote delivery 'end of this rail line is commanded 'by positive control means which preferably comprise a set of timing land c'utoff valves disposed in tandem, each independently operated by a suitable actuating gear. The opening of one such control valve serves to time the yfuel injection into the engine cylinder while the other is regulatably relatively high pressure and the pump chamber is equipt with aj bleeder or relief valve adapted to bypass all surplus fuel as soon as the rail line reaches a predetermined pressure.

As an outstanding feature of the present lnvention, the fuel pump proper may readily be located at the aft end of la long multicylinder marine engine while the rail lines may run some considerable distance forward, and this pump will still be capable of adequately serving the more remote engine .cylinders without suffering from permcious effects which usually result when attempting to transmit timed plunger impulses through relatively long fuel feed lines, es-

pecially so where the nozzle line is periodically droppedto atmos heric pressure between successive pump elivery strokes.

In order to meet such conditions to the best advantage, the plunger of my fuel pump is preferably provided with an impultion drive which is made to work in conjunction with the plunger displacement produced by its rigid actuating gear, tb the Vend that the -pump delivery is in part made up by the impulsion kick7 displacement and 1n partby the increment of plunger movement imparted by the actuating gear.

As used in-connection with a directly reversible oil engine, the plunger drive eccentric serving to reciprocate the rigid actuating member of my pump, is preferably set 1n an approximate quadrature relation to the engine crank which this pump serves. The impulsion' drive then superimposes an 'augmented movement over that which the actuatin gear alone is capable of imp-arting t0 the p unger during the injection period.

In the present system of fuel injection, all pump va ves remain closed during the initial portion of each discharge stroke of the plunger actuating gear,land during this time impulsion energy is stored within the resilient plunger drive and a high 'ressure set up within the pump chamber. stored behind the plunger is subsequently released by suitable control means which then allows fuel to be rapidly sent forth into the engine cylinder. The impulsion drive uch energy ion greatly accelerates the relatively slow movement 1mparted to the plunger by the actuating gear and maintains a more nearly uniform velocity through thes ray nozzle dur- Iing the fuel injection period), and especially so at slower than full engine speed.

A still further object of the present invention is to provide means for cross-connecting and suitably controllin a set of the de- ',scribed pumps so that t ey may be utilized [for delivering fuel to the respective power cylinders in both the forward and the reverse running directions of a multicylinder oil engine, all without need of a reverse clutch or other drive shifting means for the pump or engine shafts.

The present invention also includes certain other co-ordination in the pipe line connections and comprises various additional features of structure and organization, all of which will be pointed out hereinafter.

Reference is had to the accompanying two sheets of drawings which illustrate an example -of a 'specific embodiment of my invention; like characters of reference indicate like parts in the several views, and in which drawings:

Fig. 1, is an elevational side view of a twin plunger fuel pumg'showing the assembly of parts require to feed a set of cross-connected rail lines.

Fig. 2, shows an elevational view of the assembled pump as taken in section along line 1"-1 of Fig. 1. I

Fig. 3, is a top or plan'view of F1g. 14.

Fig. 4, represents an elevational side view of the upper portion of twin power cyl1nders for a vertical oil engine showing the disposition of the control means which command the discharge ends of my plural rail feed lines, and also a diagrammatic representation of the oppositely disposed crank pin setting used for reciprocating the respective power pistons.

Fig. 5, is an elevational end view of Fi 4.

Fig. 6, shows a sectional block detai of one of my control means which commandsthe fuel delivery from one rail line to its injection nozzle as taken along line VI-VI of Fig. 5.

Fig. 7 is an enlargement of certain link details indicated in Fig. 5 and at the same time represents an elevational end view of Fig. 6 to illustrate the type of'toggle linkage that may be used for actuating one of my tandem control valves.

Fig. 8, represents a similar view of the other end of Fig. 6 and shows the linkage used for the other of my tandem control valves.

Fig. 9, is a fra mental sectional detail of a spray nozzle p ug of the open type disposed in the top of the power cylinder, as taken along line lX-IX of Fi 4:.

Figs. 10A and 10B are valve dlagrams pertaining to said control means and succinctly illustrate the underlying principlev by means of which either one of said tandem valves carrying a split bearing 11", 1 b and 11,`

for mounting the pump drive shaft 12. vSaid shaft is intended to be positively driven off the engine crank shaft and mounted thereon are two eccentrics or crank throws 13l and 13", 'set in opposition to each other such that Fig. 2 may be taken to represent a sectional 'view through either the line I- or the line I-Ih except that lin the last named section, the plunger would at that instant be moving downward instead of u ward when the eccentric 13b is rotating in t e direction of the arrow shown in Fig. 2.

The' eccentric straps 14'L and 14" engage respectively with the wrist pins 15and 15 and preferably serve to impart a fixed stroke reciprocating movement to the respective spring casings 16* and 16". are slidably mounted in the adjacent guide bores 17l and 17 b respectively and each casing serves to independently actuate the plunger 29* or 29b as mounted in separate pump blocks.

The tubular or bored casin 16l encloses and slidably mounts a hol ow stem or plunger drive member 18'L and this is provided with an outwardly disposed drive -flange 19 and also with a recessed internal collar flange 20. The lower end of the bored casing 16 is partially inturned to constitute a bottom flange 21'* and fitted thereto by means of bolts 22'l is a fork flange 23l which carries the wrist pin 15. The fork flange 23* may be centered within the opening vof the bottom flange 21 and provided with an extension iece 24l serving as a stop 'for limiting the ree downward travel of the drive flange 19a. The upper end of the bored casing 16a is internally threaded and fitted with an annular casing nut 25a having an externally threaded tang 26. Said nut forms a guide about the Stem 18L while the drive flange 19* and said stem are intended to travel back'and' forth within the casing bore as a unit.

Thrusting between the flange 19 and the bottom caslng flange 21, is a nest of relatively powerful primary springs 27 and 27" of which the larger one is centered by These casings the casing bore. Mounted abovethe drive flange 198L and thrusting against the casing nut 25, is a single `secondary spring 28 whose outside diameter is somewhat smaller than that of the lower primary spring 2T to provide clearance room for the circumscribing nut tangl 26a. It will be seen that said secondary spring is set to act in opposition to said nested primaryv springs.

These opposed drive springs are intended to be forced into place under a considera-ble initial tension so that the drive flange 19 is normally made to assume the relatively fixed balanced posit-ion with respect to the casing abutments as is indicated by dotted lines in Fig. 2. lVhen, however, the plunger 29Ja Works against a high chamber pressure and becomes fully loaded on its upward stroke, this will cause the drive flange 19a to assume its extreme lower or full lined position shown in Fig. 2..

The reciprocating parts 13a, 14a, 15a and including the various members that are secured to the casing 16a, serve as the rigid actuating gear of this impulsion fuel pump, While the intermediate resiliently mounted members with their springs such as 18, 19, 20a, 27 and 28a serve as the impulsion drive for the pump plunger 29a.

The extent to which the drive flange 19a may normally be displaced out'of its balanced position With respect to the casing, is designated by the distance K. lVhen this flange is thus fully displaced, the primary springs will then b'e carrying substantially their maximum expected plunger load, While the secondary spring Will be almost Wholly expanded although it is intended to still retain a small portion of its initial counter thrust.

The pump block 3()a which is independent of but similar to the complementary block 30", is preferably securely Jfastened to its guide bore 17a by means of suitable stanchions or the like. Within this block is mounted the reciprocating plunger 29a which may be sealed against leakage by the packing 31*EL and adjusted by means of the gland 32a. If preferred, the plunger may be ground or lapped into a suitable sleeve bushing secured to the block in the manner of said gland. In either case, the plunger is intended to Work reasonably free through such packing means so as not to interfere unduly with the action of the impulsion drive springs.

The. lower end of the plunger 29a may be removably secured to the recessed collar flange 2Ou by means of an intermediary foot flange 33 which is loosely fittedwith respect to the collar recess as shown. The pull-back flange 34a is provided with, a hole that surrounds the plunger and is made to hold the foot flange in place by means of bolts 35a screwed into the collar flange.

tion valve 8T and 37 respectively and a' common fuel supplyr pipe 38 feeds these suction valves preferably under slight pressure through separate block passages such as 38a and 38h.

Each of the suction valves is equipt with variable lift regulating means'and in the present instance, this comprises an oscillating governor shaft 39 mounted in the block 30*l and disposed crossn'ise of the suction valve axis. Within a suitable pocket formed under the valve stem and overhanging one end of said shaft 39a, is a toe element adapted to engage the bottom of the 'stem and variably lift the suction valve 37a off its seat for governing purposes. The respective actuated endsof the parallelly disposed shafts 39a and 39h may be interlocked by the gear sectors 39'3 and 39d Which then simultaneously lift yboth of the suction valves and the pin 39 carried by one of said sectors may be attached to the governor (not shown). In the case of marine engines, it is generally preferred to utilize the described mode of regulation for emergency cut-out purposes ratier than normally control the fuel delivery to the injection nozzles by these means.

Protection for the respective pump blocks against abnormal chamber pressure is afforded by the independent relief or bleeder valves 40 and 40"'` which communicate freely with their respective pump chambers as shown. The bleeder overflow or surplus fuel is preferably returned to the source of supply by means of the vent pipe 41. The particular type of controllable bleeder valve used is immaterial for present purposes but as shown in Fig. 1, this valve .essentially comprises a valve plate 42a adapted to close a relatively small relief aperture and this plate is loaded by means of a spring e5 which in turn is 'equipt With adjusting means 4st@ such .that the maximum chamber pressure and that maintained in the rail line may be conveniently regulated to suit requirements. It is emphasized however that the use of such bleeder valve performs a further important function in that it serves to bypass the surplus pump delivery and prevents any material rise over predeter mined pressure behind the fuel injection nozzle in case the fuel requirements shouldv be reduced or even wholly cut off at light. engine loads and under Which condition-e the nozzle pressure would otherwise tend to build up rapidly and greatly exceed that obtainedl under full load conditions:

fil() these twin fuel pumpsare-inade to serve re-` The pump block al is further provided with a pump delivery valve 45 preferably of the automatic' check or other type o f non-return valve openingoutwardly from its pump chamber inthe conventional manner and delivers into the end of the rail line section 46. The twin block .30" is similarly equiptv with a check valve 45" and this delivers into the intake end of its rail line sect-ion 46". When versible power cylinders whose pistons oper- -ate off oppositely disposed' engine crank i throws such as are indicated in Fig. 4,V it is then preferred to interconnect the rail lines 46 and 46" by means of a cross pipe 47 which may be arrangedne'ar the pumpV unit as shown 1n Fig. 1.

'In the present-system, the described fuel pump unit may safely be located at a considerable distance from'the power cylinders 4 which it serves. As applied -to a directly reversible marine oil engine, the pump shaft 12 may be driven off the aft end of the crank shaft through gears orlike medium (not shown) capable of maintaining the proper quadrature relation between the set of opposite pump throws 13* and 13" andthe set of similarly disposed engine cranks.

mote end portions of the respective rail line sections designated as 46" and 46" in Figs.

v4 to 8, these lines preferably connect inte the bottom of the respective control bodies 48 and 48" as shown. One complete body withl .the necessary actuating mechanism 1s rovided for each of the twin power cyliners 49" and 49", andout of the top of said bodies, short feed pipes such as 50* or 50" respectively lead'to the nozzle plugs 51'* and 51". As disclosed in Fig. 9, the injection nozzle tit or aperture 52" is preferably but not necessarily of the conventional open type adapted to impinge against the piston crown and this tit maybe mounted in the plug 51' and provided with a non-return valve 53a to prevent the .cylinder compression from blowing back into the feed ipe 50".

Since the structure of both t e control bodies 48l and 48" ma, be identical, the detailed description will e confined to the latter. It will be observed that the body 48" preferably comprises two interconnected but separable superimposed 'sections havingl mounted ltherein a spring closed top control valve 54" and a s ring closed bottom control valve 55" wliic are disposed in tandem relation along acontinuation of the rail line 46", each such valve being inverted to open inwardly against existing rail line pressure such that when either of said valves is Vseated, no fuel can flow-through the control bod 48".

Tlie uppermost of said body sections may intake Referring now in detail to the control' means which commandV the discharge or re carriesthe spindle arm 58 which is oscillated `in unison with the corresponding power piston movements by means of a suitable intermediary linkage. The lower body section is likewise provided with an actuating spindle bhaving a li means 57" which engages the stem end o the lower valve 55" in a manner identical with that described except that this spindle and its arm 58" is now dis osedto extend out vof the opposite side wal of the lower body section and this arm is osci'llated by an independent toggle linkage.

As shown in Fig. 4, a horizontal camshaft 59 is transversely disposed alongside the various (power cylinders and said shaft is intende to be directly driven from the engine crankshaft by means of suitable gearing such as 60 or the like. Said camshaft carries two eccentrics 61l and 6l" for each of said power cylinders and these respectively impart reciprocating movement to`the set of h slides 62* and 62" which in turn are made to actuate the linkages used for oscillating the respective spindle arms 58" and 58". Each Set of eccentrics such as 61* and 61", is preferably mounted in ya quadrature relation upon the camshaft 59 and made to straddle,

the corresponding engine crank position which they serve, that is to say, when any particular power piston reaches its dead center, one of said eccentrics will already have passed its upper dead center position while the complementary eccentric will still lag behind its up er dead center position, it being preferre to operate the topmost valve off said lagging eccentric when the engine is running rection.

Instead of using a single control valve to admitfuel to the engine cylinder and at thesame time variabl closing this same valve in accordance to tiie fuel requirements, it is preferred in the present invention to in a forward or ahead di- `separate these functions and perform same by means of two distinct valves, one of which admits fuel from the rail line to the engine cylinder while the other valve cuts it off. This arrangement permits of a more -rapidout-off without excessive wire drawing and otherwise improves the fuel control.

The underlying mode of operation as applied to said tandem valves is best made clear by means of the valve diagrams shown in Figs.10^ and l0". Referring first to the madera forward running diagram Fig. 10A, the point C represents the inner or top dead center position of the engine crank throw, i. e., the point of maximum compression 1n the power cylinder. The leftward crosshatching marked L shows the preferred setting-given to the lower or bottom valve 55" which in this instance servesas the fuel cut-off valve while the rightward crosshatching marked U shows `the preferred setting given to the Upper or top valve 54". Accordingly, the valveeo" is first made to positively open against rail line pressure .at a point A and to close at the point B while the lagging valve 54" is made to open at D and to close at E. Between the points l) and B the respective valve openings will overlap and at the pointD fuel will-therefore begin to be sent forth vin the englne cylinder and out of the remote end of this par ticular rail line. At this instant, the lower valve 55" will already have passed its maximum lift and will be dropping toward its seat and finally reaching its seat at the point B, whereupon the fuel is cut-ofi' from Jche cylinder although said upper valve does not seat until the point E is reached. Hence between the points A to D also B to E, only one of the tandem valves will be open but no fuel can then pass through the valve body, while between the polnts E to A neither valve is open, thus doubly sealing the rail line against leakage into theY engine cylinder.

The fuel injection period is determined by the points D to B as shown b the double cross-hatched diagram area an during this time, fuel may freely pass through the control block. ln order to regulate the fuel delivery into the engine cylinder, suitable means may be provided for changing the period D to B during which both of said tandem valves remain open together. For forward running of the engine, this may readily be brought about by lifting lthelower valve 55tl to a lesser extent which would result in opening this cut-ofi' valve at a later point such as A and in closing same at an earlier point as B', thus restricting the injection period to D-B and allowing a much small quantity of fuel to pass out of the remote end of the rail line and upon such control closure, any surplus pump delivery will thereupon be discharged through the bleeder valve. It is preferred to variably control the lift of only one of said tandem valves at a time in order to maintain a fixed fuel injection lead D--C with respect to the power piston dead center C.

The present invention further provides for a twofold use of said tandem control f" valves in that they may be alternately utilized in either the forward or reverse running of the engine and this is attained by merely reversing the functions of said upper joined to a togg and lower valves as is indicated in diagram 10B. It will be seen that in reverse running, the lower or bottom valve is now made to function as a fuel timing valve while the upu per valve serves as the 'fuel cut-od valve.

Having set forth in general terms the reversible principle that underlies fuel egress from the described rail line, further reference is now made to a specific link device that will admit of carrying out this improved method of fuel control. As shown in Fig. 7, the outer end of the upper rocker arm 58n is pivotally connected to the overhung slide pin 63" by means of a toggle link comprising a toggle arm 64" adnent link elements are reciprocated as a unit. A shift-ing gear is used for changing the relative alignment position of these toggle link elements while running; for making such adjustment, the toggle arm may be extended somewhat to provide for a guide pin 6g?) which carries one end of the guide strap 6 pivotally held or positioned by the throw arm 68", which arm swings on the fixed in 69" and is provided with a roller 70" hel in engagement with the adjusting cam 74 lo means of a tension spring such as 7 5" lor the like. A plurality of similar cams are mounted upon the throw shaft 7l which extends along the front of the various en ine cylinders and it will be seen that a set o oppositely disposed cams of this kind are provided for each cylinder and respectively mounted on each side of their control bodies such as 4:8". As shown in Figs. d and 5,0ne end of the throw shaft 71 may be equipt with a control sector 7 2 having a manipulating lever 73 to turn said shaft within prescribed limits.

As regards the contour of the cam 7d which engages the roller this may be provided with two oppositely disposed lobes, one 74a being relatively short and another somewhat longer lobe 74e", each having a rounded face about the throw shaft center and connected together 'by means of the tangential fiat face 7 4. In Fig. 7 the longer lobe 74" is set topmost while in Fig. 8 the cam setting is reversed for reasons that will appear presently. When the manipulating lever 73" is placed in its mid or horizontal position, the flat face 7 4 of the various cams is intended to assume a vertical position as shown dotted and this allows all the respective throw arms to be drawn nearest to the throw shaft 71.- Under such lever setting, the straps 67a and 67" will then pull thelr respective toggletlinks out of ali ent to the maximum extent and into thelr extreme angular positions indicatedby dotted lines in Figs. and 8 respectively. As a result, the respective spindle arms 58" and 58" will The other free end of said strap is e link 65" and such compo be drawn downward and their spindle lips l o moved away suiciently from the co-acting stems to prevent openln of the respective valves 54b and 55", notwit standing that said slides 62* and 62b may still be imparting reciprocating movement to their respective toggle links.

Assuming that the lever 73 is now placed into its intermediate forward position as shown in full lines Fig. 5, then the various cams 74 will'take the respective full-lined ositions shown in Figs. 7 and 8. The roller 0b will now have engaged the top face of the short lobe 7 4 thereby shiftingiits toggle linkage (64b and 65") into the fu -lines osition shown in Fig. 7, while the other ro er 70. will still be engaged with its tangential cam face such as 74 but will not as et be ridin upon the round top face of its onger lobe 4, all as shown in full lines Fi 8. The toggle linkage in Fig. 7 is then ma e to actuate the upper valve 54b as a fuel tuning valve and it will be observed that any continued turning of its cam inthe direction of the arrow would not shift this tog le linkage into further alignment. On t e other hand, the roller 7 0a has not yet reached the crest of the cam face 74b and hence as the lever 73 is moved. into its extreme lower dotted position, this will bring the toggle linkage shown in Fig.v 8 into closer ah nment until finally the substantially l1 alignment position is reached as shown in dotted lines. -Obviousl ,the described shifting of the toggle ll age causes a corresponding lag 1n the opening of the lower valve 55" and a roportional lead in its closing time, whicli in turn determines the point of fuel'cut-oif into the engine cylmder. 1

Hence a change in the setting of the lever 73 will correspondingly'bring about a variation in the cut-o' timin and superimpose same upon the substantia y fixed setting of the timing then bein given to the upper valve 54",-all in accor ance with the requirements previousl pointed out in connection with the valve diagram Fig. 10A. When the lever 73 is carried back into its mid osition, this will completely out off fuel rom all the cylinders while engine reversal is bein effected. Should the lever thereupon be drawn upward, it will reverse operations as far as the tandem control valves are concerned, causing the upper valve 54b to function as a cut-oft' valve while the lower valve 5 5b is then converted into a fuel timing valve in. accordance with diagram 10B.

Having described in detail the parts of a specific embodiment of my invention, the manner in which they co-operate is as follows Assuming the pump cranks to stand in position shown in Figs. 1 and 2 and the engme to be running in a forward direction as indi- `discharge stroke position marked w, the

plunger 29EL will during its preceding down stroke have sucked a charge of liquid fuel into its pump chamber through the suction p valve 37a in excess of the fu l-load engine requirements. During such suction stroke, the drive flange 19 except for plunger slip remains in substantially its dotted or balanced position with respect to the casing 16". As soon however, as the eccentric 13a has passed its lower or outer dead center position and begins to lift said casing, the resulting reversal of stroke promptly closes the automatic suction valve and the dischar e valve 45 will also remain closed for t e timeA being because of the rail being maintained at iixed pressure; as a result, the initial lifting of the casing 16 against increasing chamber ressure will cause the flange 19a to be displl) as is indicated by the letter K. Such maximum displacement of the impulsion drive parts against the combined resistance of the primary and secondary springs preferably occurs during the initial portion of each discharge stroke of the actuating gear and its function is essentially that of an hydraulic accumulator. The described disp acement ofthe drive parts, stores impulsion energy within said drive springs and it at the same time sets up a correspondingly high hydraulic pressure throughout the pump chamber passages as well as under the closed discharge valve 45.

Assuming that the engine is running with the manipulating lever 73 set in its fulllined or forward running position and that the pump end of the rail line 46 is served by the discharge valve 45 while the remote end 46a of the long rail line is connected to the control body 48 as described, and further assuming that said rail line has already been pumped up and is held under a predetermined pressure while starting the engine, then at or about the instant that the pump chamber reaches the existing rail line pressure, this will cause the automatic discharge valve 45a to lift and start fuel delivery into said rail line. Prior to this instant however, a full quota of impulsion will have been stored within the resilient plunger drive-irrespective of the engine fuel requirements and the bottom control valve such as 55 will already have been opened while the top control valve such as 54b will be just about to open, hence as soon as both of these valves are opened together, high pressure fuel will immediately rush toward the injection nozzle 52 and thus set up aiiow within the rail line. As a consequence, the rail line pressure will tend to drop somewhat and this in turn releases the energy stored aced by an amount such :Laconia behind the impulsion plunger and, allows' it to be impelled onward with respect to the normal discharge stroke movement of the actuating gear.

After sufficient fuel has been injected into the engine cylinder, the lower valve such as 55b may be made to close and thereafter the pump completes its stroke and brings the rail line back to the predetermined pressure fixed by the relief valve 40a. Any surplus delivery resulting from the small remainder or unfinished plunger stroke, drives any eX- cess fuel through the valve 40a and returns same by the pipe 38 to the supply reservoir of the pump. As soon as the end of the pump discharge stroke is reached and a reversa-l of plunger stroke occurs, the resultino` closure of the discharge valve 45a will hold back the pum ed up rail pressure and prevent it from ropping into the pump chamber, this chamber thereby being kept at low pressure and able to uno structedly draw in a new charge of fuel prior to again forcing same into the rail line as previously described.

The described mode of umping operations allows of invariably reacliing predetermined rail line pressure under all engine load conditions; it also insures of a more accurate and reliable measuring of the effective fuel delivery into the engine cylinder, the surplus fuel being regulab bypassed in accordance with the particu ar setting given to the interdependent fuel control valves. It is `further pointed out that the building up of the rail line to redetermined pressure prior to the end oft e plunger discharge stroke, represents an important feature of the present inventionA since it insures that the resilient plunger drive will always be made to store therein a substantially constant amount of energy or impulsion edort regardless of the effective fuel delivery into the engine cylinder; that is to say, the rail intake valve 4521 is not allowed to open until the plunger impulsion drive has been fully charged and hence said check valve is in effect made to function in an equivalent fashion to a positively opened vpump discharge valve as far as present purposes are concerned.

Each of the twin pumps shown in Fig. 2 is intended to function in an identical manner except that when used for reversing purposes, their opposed cranks are preferably set in said quadrature relation with respect to the similarly disposed engine cranks. By virtue of the cross-over pipe 47, the pump designated II in Fig. 4 may be made to serve the power cylinder I when running in the reverse direction while the pump I then serves the cylinder II. When running forwardly, the two rail lines may be kept entirely independent by shutting off the emergency valve 47 a which provides for increased reliability in the event of pipe line rupture or other serious defect arising in one or the other of the pump systems.

It is thought the manner in which the opened cross-over pipe is intended to function for reversing purposes will be obvious m from the previous description; briefly, the pump I is normally intended to serve the cyl?J inder I during forward running of the engine, but upon reversing the engine, the pump I will then be lagging by 180 with respect to the engine crank of cylinder I and thus assume the required phase relation for serving cylinder lli., all without need of any reverse gear for otherwise shifting the pump drive shaft. The result of opening the cross over pipe 47 is to double the pressure impulses set up in each of the rail lines and such impulses may be selectively picked up by the res ective rail control bodies and sont forth to t eir power cylinders in proper se.- quence to meet their fuel requirements.

It will be apparent that the quadrature relation between pump and engine cranks is not essential for the described operation of the rail system except when they are intended for reversing purposes. Furthermore, while the disclosures have been more particularly directed toward fuel pumps for two-stroke engines, the same underlying principles find application to four stroke engines as well, it being merely necessary to keep the pump plungers in proper phase relative to the respective power piston movements, preferably by running one pump at engine shaft speed and making this serve two cylinders alternately.

To start up the engine in either direction, starting air is thrown on by conventional means (not shown) and this will serve to pump up pressure in the rail lines in case this does not already exist because of previous runs. Then by slowly throwing the manipulating lever 73 intothe direction of running, fuel will be delivered to the engine cylinders to the extent that said lever may be shifted away from its mid or neutral position, the surplus fuel in excess of engine requirements being regulably bypassed through the relief valve, as described. The lever 73 may readily be interlocked with the movement of the centralized control lever for the engine, if so desired. The quantity or charge of fuel sent forth by the pumps into the respective engine cylinders is preferably regulated by the eut-off point as fixed by the manipulating lever. However, it may be pedient to regulate the pump delivery by other means and if preferred, this may be accomplished by resorting to a variable lift gear for changing the time of closure of the pump suction valves in the manner previously indicated.

The present improvements differ in essential particulars over competing fuel injection systems in that it provides for effective imioni pulsion or accumulator effect in connection with long rail lines and means for adequately sustaining such effect for all engine loads; an important element which leads to thc desired results resides in maintaining such lines under high ressure between p ump delivery strokes. wing to the resiliency of the liquid fuel itself and also that of the long rail lines considered as a container therefor, a considerable loss or dissipation of effective plunger displacement is involved when such charged rail line is periodically relieved of hi h pressure and needs to be again fully built up or replenished after each and every fuel injection. In the described mode of operation, the liquid fuel together with any entrained air that may li e within the long rail lines is maintained at high pressure and prevented from expanding back 1nto the pump chamber or otherwise upsetting operations while the plunger sucks in a new charge of fuel. On the other hand, as soon as the fuel delivery from the pump begins, there is no pernicious lag involved in brin ing all portions of the rail line and especial y its remote end up to maximum pressure at the very instant when it is critically needed for injection pur oses and this result is primarily effecte by means herein provided which insure charging the resilient plunger element with impulsion energy in requisite amount prior to any effective fuel delivery into the engine cylinder. In the present system both the entire rail line section and its pump chamber are already brought up to predetermined workin pressure prior to admitting any fuel to t e cylinder nozzle.

Moreover, where a rail line is held under( considerable pressure but is served by a conventional pump of integrally driven plunger type, this method is still deficient for the reason that this type of fuel pump is incapable of momentarily augmenting `its effective rate of fuel delivery during the injection period. Unless such a pump provides for abnormally large .gross displacement, the engine cylinder will be obliged to draw heavil upon the rail line pressure for its require surplus fuel needs in excess of the momentary effective capacity of the pump; accordingly when working with usual pump proportions of the integrall driven plunger type, a decided drop in rail pressure occurs behind the nozzle when the fuel begins to inject into the cylinder. The impulsion plunger serves to check such detrimental pressure drop and maintains a far more uniform pressure behind the nozzle which in turn promotes perfect atomization of the fuel during the entire injection period.

The high pressure rail system herein disclosed affords the further advantage over impulsion pumps heretofore devised in that fective its size of fuel delivery pipe may be made as large as may be necessary to obviate excessive flow pressure drop between the pump and its most distant power cylinder when served b long nozzle feed pipes. Where attempt is made to rapidly bri up a long nozzle pipe line of this kind rom low to a really high pressure during each pump delivery stroke, the liquid fuel content of such a pipe line must be ke t Within narrow limits otherwise much o 'the efpump displacement will be dissipated in boosting the delivery line pressure. It will be evident that this inherent lag results in a gradual rather than in the desired rapid rise of pressure at the remote end of the feed pipe and hence such methods do not provide for a properly sustained fuel pressure head behind the nozzle during the critical injection period. Where lon lines of too small a bore have to be resorted to in order to curtail such lag effects, then abnormal flow pressure drop results and the pump efficiency is vitally reduced as compared to the herein described rail line charging method.

Obviously the rail lines need not necessarily be kept divided into separate entities as escribed but under certain circumstances may be combined into a common feed pipe having appropriate branches leading to the respective engine cylinders, and it will be further understood that I do not wish to be limited to the specific embodiment set forth as an example of my devices, since variouschanges in structure and coordination of parts may be resorted to without departing from the spirit and scope of the present invention, heretofore described and more particularly defined in the appended claims.

Claims: 1. In a fuel injector system comprising vin combination, a rail-line section maintained at predetermined pressure and the discharge end whereof communicates with the com ustion chamber of an internal coml bustion engine equipt with a cylinder and a piston means to obstruct the discharge end portion of said rail-line, means adapted to intermittently deliver fuel to the receiving end of said rail-line and establish a. pressure therein, said means comprising a plunger adapted to pum surplus fuel in excess of requirements an actuating means for said plunger having a. resilient member interposed therebetween, means to remove said obstruction Ain timed relation to the piston movements, said removing means comprising means to vary the duration and extent vof said removal, relief valve means serving' to regulably bypass said surplus fuel while saidrail line is obstructed, and means adapted to hold predetermined pressure within said rail-line and behind said 'obstruction while the delivery of fuel into 'with a plurality of cylinders each having a piston therein, means to obstruct said branches, means adapted to pump surplus fuel in excess of requirements into said railline, said means including a plunger and actuating means therefor with an interposed yielding means adapted to establish pressure in said rail-line and the branches thereof, means to periodically remove said branch obstructions in timed relation to the respective piston movements, relief valve 4 means serving to re ulably bypass said surplus fuel' while said ranches are obstructed, and means adapted to hold said rail-line under predetermined pressure while said branches are obstructed, said last named means being reopened upon storing within said interposed yielding means a substantially constant plunger impulsion effort irrespective of the fuel bypassed through said relief valve.

3. A fuel injector comprising in combination, a distributing system having interconnecting plural-rail-lines the respective discharge ends whereof deliver fuel to the combustion chambers of diderent power cylinders each having a piston therein, means to obstruct the discharge end portions of each of said rail-lines, means to deliver fuel to said rail system including yielding means adapted to periodically establish a predetermined pressure in said rail system, means to remove said obstruction in timed relation to the piston movements, and means adapted to hold said -rail system under pressure while said rail lines are obstructed and the delivery of fuel into said rail-line is inter'- mitted.

4l. ln a fuel pump for internal combustion engines of the injection type, said pump being adapted to deliver surplus fuel in excess of requirements and comprising a reciprocating actuating part and a driven plunger part, an impulsion drive interposed between said parts, means for storing en ergy within said drive which energy is brought up to a substantially constant amount during each discharge stroke of the pump regardless of engine load conditions, a non-return discharge valve for the pump, a rail-line leading from said valve to the injection nozzle of the engine cylinder, said rail being held under pressure by said valve with respectfto the pum chamber during the plungerl suction stro e, control means commanding the remote cylinder end of said rail adapted to release said energy and allow of impelling the plunger part onward during the period of fuel injection into said cylinder, and relief valve means serving to tix said rail-line pressure and to regulably bypass saidsurplus fuel'.

5. In an internal combustion engine. in which liquid fuel is injected into the power cylinder, a fuel injector means adapted to deliver surplus fuel in excess of engine requirements and comprising a plunger part and an actuating means therefor having a resilient drive member interposed therebetween, a conduit means establishing commu` nication between said injector means and the power cylinder, a non-.return valve commanding the receiving end of said conduit, means for periodically storing impulsionenergy behind said plunger part, said ener being kept substantially` constant from stroke to stroke regardless of change in engine fuel requirements undervariable load conditions, control means for said conduit interposed between said check valve and the cylinder, said means being adapted to release said energy and allow of impelling the plunger onward while said injector is delivering fuel into the engine cylinder, means tocut od' said cylinder delivery, `said check valve thereupon serving to hold pressure within said conduit between the successive delivery periods of the fuel injector,

and relief valve means serving to llimit said rail-line to predetermined pressure and to regulably bypass said surplus fuel-during said cut-od' period. l

'6. ln an internal combustion engine in which liquid fuel is' periodically injected into the power cylinder, av fuel` injector means adapted'to deliver surplus fuel in excess of requirements, said injector comprising a movable plunger and an actuating means therefor having a resilient drive member interposed therebetween, a hleeder valve set to relieve at predetermined pressure and adapted to regulably bypass said surplus fuel, a conduit means establishing communication between said injector and the cylinder, a non-return valve commanding the intake end of said conduit, means for periodically storing impulsion energy behind said plunger part, control means for said conduit interposed between said nonreturn valve and the cylinder, said means being adapted to release said energy and allow of impelling the plunger onward while `said injector is delivering fuel into the en-f gine cylinder, means for cutting off the fuel delivery into` the engine` cylinder, said injexstor being adapted to continue fuel delivery and raise said conduit to predeternel mined pressure during said cut-off period whereupon said non-return valve serves to hold predetermined pressure within said conduit between successive injection periods into the power cylinder and is reopened only after a-suicient amount of impulsion energy as fixed byfull load needs has been stored behind said plunger regardless ofv change in engine fuel requirements.

7. In a multi-cylinder internal combustion engine of the injection type, a fuel pump adapted to deliver surplus fuel in excess of full-load requirements and disposed in close proximity to one end of the engine crankshaft, said pump comprising a plunger and a reciprocating gear therefor driven from said shaft end and adapted to actuate the plunger through an intermediary resilient drive means for storing impulsion energy within said drive, said energy being kept substantially constant'under all engine load conditions, a rail-line section maintained at predetermined pressure and leading from said pump to the `injection nozzle serving a distance cylinder located at the other or far end of said shaft, a check valve commanding the receiving end'of said rail serving to hold ressure therein, control means for said rail-line interposed between the check valve and said nozzle, said means being adapted to release said stored energy to impel the plunger onward and momentarily augment the rate of fuel pump delivery into the cylinder over the corresponding increment 0f movement which the reciprocating gear of itself would be capable of impartlng to the plunger, means for cutting off said cylinder delivery, and relief valve means serving to regulably bypass said surplus fuel during the delivery cut-off period.

8. In a reversible fuel pump unit serving a multi-cylinder direct injection oil engine having a pair of oppositely disposed cranks and power cylinder appurtenances therefor, said unit comprising a pair of independent pumps each provided with a chamber, a reciprocating plunger part and a gear adapted to actuate the plunger through an intermediary resilient drive, said gears serving to move the plungers in opposite directions as they approach their respective mid stroke positions. means for storing impulsion energy within each such drive, a non-return discharge valve for each of the pump chambers, a conduit interconnecting said valves and communicating with the respective injection nozzles of said pair of cylinders, said non-return valves serving to hold said conduit under pressure relative to their pump chambers during the respective plunger suction strokes, means to removably obstruct delivery of fuel from Said conduit into each of said cylinders, means for alternately removing said cylinder obstructions to release the respective plunger drives and bring about an augmented rate of fuel delivery from one pump into one of the cylinders and from the-other pump into the other cylinder, and shifting means adapted to effect a crossover in the designated pump deliveries when the engine is run in a reverse direction causing said. one pump to deliver into said other cylinder and said other pump to deliver into said one cylinder.

9. In a reversible fuel pump unit serving a multi-cylinder direct injective internal combustion engine having a pair of oppositely disposed cranks and power cylinder appurtenances therefor, said unit comprising a pair of independent pumps each provided with a chamber, a reciprocating plunger and a ear adaptedl to actuate the plunger throug an intermediary resilient drive, means for storing impulsion energy within each such drive, a non-return dischar e valve for each of the pumps, a railline eading from one 'of said valves to one power cylinder, a second rail-line leading from the other of said valves to another power cylinder, said rails while the engine runs in one direction each being independen'tly held under pressure relative to the pressure existing in their respective pump chambers during plunger suction strokes, a cross over conduit interconnecting said rail-lines serving to transfer pump delivery from 4one to the otherof said rail-lines when the engine runs in a reverse direction, and means for obstructing said crossover conduit while the engine runs in said first named direction.

10. A fuel injector adapted to deliver surplus fuel in excess of requirements and comprising in combination, a fuel conduit provided with distributing branches, the discharge ends whereof respectively communicate with the combustion chambers of an engine having a plurality of power cylinders, means for removably obstructing each of said branches, accumulator means including a yielding plunger means adapted to periodically store energy to establish pres-v cumulator is intermitted, means for removing said branch obstructions in synchronism with certain ofsaid pressure impulses to successively admit fuel into the respective power cylinders, means for cutting off the said cylinder deliveries, and a common relief valve means serving to regulably bypass said surplus fuel during the intervening cut-oft' periods.

11. A fuel injector comprising in cornbination, a fuel conduit provided with distributing branches, the discharge ends whereof respectively communicate with the combustion chambers of an enginex having a plurality of power cylinders, means for removably obstructing each of said branches, accumulator means including a yielding plunger means adapted to periodically establish pressure impulses within and deliver fuel to said conduit and branches, said impulses being appropriately timed to meet the .engine fuel injection requirements, means for charging said accumulator, means for. holding said conduit under pressure while the fuel delivery from the accumulator is intermitted, means for successively` removing certain of said branch obstructions in synchronism with certain of said pressure impulses while the engine runs in one direction, and means to change the timing of said removal means to admit of injecting in proper sequence into the aforesaid power cylinders when the engine is reversed.

12. A fuel injector adapted to deliver surplus fuel in excess of requirements and comprising in combinat-ion, a fuel conduit section relatively long in proportion to its bore and delivering to an oil engine cylinder for injection purposes, means for removably obstructing the discharge end portion of said conduit, accumulator means includin a yielding plunger means adapted to periodilcally establish high pressure impulses within and deliver fuel through said conduit, said conduit having a cross sectional area of sufficient size to obviate excessive flow pressure drop and a fuel conte-nt relatively large in proportion to the delivery capacity of said accumulator, and means for storing a substantially fixed amount of impulsion energy within said yielding plunger lmeans irrespective of the engine fuel requirements, said last named means including 'a non-return valve adapted to hold the conduit under pressure between said. impulses and to admit fuel into said conduit when the prescribed amount of impulsion energy has been stored.

13. In a fuel injector for an internal combustion engine having a cylinder and a piston, a conduit connecting the injector with the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means, and means to remove said obstruction in timed relation to the piston movements, fuel being admitted into the cylinder only while both of said valves arev simultaneously unclosed.

14. In a fuel injector for an internal comvadapted to selectively time the bustion engine having a cylinder and a piston, a conduit connecting the'injector with the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish ressure therein, means to obstruct said con uit, said obstruction comprising separate but interdependent valve means of which one such serves asa timing medium and the other as a cut-off `medium commanding the fuel delivery into the cylinder, and means to remove said obstructions in timed relation to the piston movements. l

15. In a fuel injector for'. an internal com-` bustion engine having a cylinder and a. piston, a conduitconnecting theinjector with the cylinder, said injector being adapted to j.

deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means of which one such serves as a timing medium and the other as a cut-olf medium, and means changing the period during which'both of said valves remain open together to regulate the fuel delivery into the cylinder.

16. ln a fuel injector for an internal com.- i

bustion engine having a cylinder and av piston, a conduit connecting the injector with the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means, actuating gear means for said valve means comprising set of toggle linkages each operated in unison with the piston movements, and constraining means adapted to shift the respective toggle linkages into or out of relative alignment and selectively time the closing or unclosing of either valve.

17.- ln a fuel injector for an internal combustion engine having a cylinder and a piston, a conduit connecting the injector with the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means, independent actuating gear means for operating each of said valves in unison with the piston movements and closing or unclosing of either valve, and manipulating lever means associated with said gears serving to cut-off fuel from the cylinder when said lever is set in a predetermined position and adapted to fix the fuel delivery into the cylinder proportionally to the extent that the lever is lshifted away from said predetermined position.

18. In a fuel injector for an internal combustion engine equipt with a plurality of power cylinders andpistons therefor, a conduit connecting the injector with each of said cylinders, said'injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit adjacent to each of said cylinders, each such cylinder obstruction comprising a set of separate but interdependent valves, an actuating gear for each setlof such valves adapted to selectively time the closing or unclosing of said interdependent valves, and manipulating means associated with said gears-adapted to adjust the timing of all valve sets simultaneously. 19. In a fuel injector for an internal com\` stem for the puipose'specitied.

bustion engine having a cylinder and a pis- 23. In a fuel pump, an intermediary imton, a conduit connecting the injector with the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means .to obstruct said conduit, said obstruction comprising separate but interdependent valve means, independent actuating means for operating each of said valves in unison with the piston movements, means adapted to selectively time the closing or unclosing of such valves when one serves as a timing medium and the other yas a cut-off medium to control the fuel delivery to the cylinder, and shifting means adapted-to reverse the functions of said valves.

20. In a fuel injector for an internal combustion engine having a cylinder and a piston, a conduit `connect-ing the injector Jvith the cylinder, said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means of which one such serves as an admission medium and the other as a cut-off medium commanding the fuel delivery into the cylinder, actuating gear means for operating said valves in unison with the piston movements, and control means associated with said gear adapted to selectively time the closing or unclosing of eithervalve, said means serving to fixedly time one such valve while the other is being variably timed.

21. In a fuel injector for an internal combustion engine having a cylinder an'd a piston, a conduit connecting the injector with the cylinder,.said injector being adapted to deliver fuel into the receiving end of said conduit and establish pressure therein, means to obstruct said conduit, said obstruction comprising separate but interdependent valve means of which one suoli serves 'as an admission medium and the other as a cut-off medium commanding the fuel delivery into the cylinder, independent actuating gear means including an eccentric for operating each of said valves in unison with the piston movements, one of said eccentrics being set to lead and the other set to lag with respect to said piston movements and serving to open one of said valves in advance of the other, and control means adapted to reverse thef'unctions of said valves.

22. In a fuel pump, an intermediary impulsion drive for the plunger comprising a reciprocating spring casing adapted to mount resilient means therein, a drive flange engaging said resilient means, said flange having a stein adapted to engage the plunger, and an intermediary foot flange for the plunger equipt with pull-back means, said foot flange being provided with lateral play to constitute a slip joint with respect to said pulsion drive for the plunger comprising a reciprocating spring casing and a drive flange slidably mounted therein, said flange having a stem member adapted to engage the plunger, a primary drive spring thrusting between said drive flange and an'abutment means formed on one end of said casing` a secondary spring thrusting between said flange and the other end of the casing, said other casing end being internally threaded and adapted to receive an annular casing nut serving as an abutment for the free end of the secondary spring and through which nut extends the stem of said drive flange. and means disposed at the unthreadpld end of the casing for reciprocating said rive.

24. In a fuel pump comprising a suction valve, a reciprocating actuating part, a driven plunger part and a resilient drive member interposed between said parts, means for storing energy within said drive subsequent `to the closure of the suction valve, control means commanding the pump delivery adapted to release said energy and allow of impelling the plunger onward to limpose an augmented rate of movement upon the plunger part, and adjusting means adapted to variably delay closure of said suction valve and regulate the delivery of said plunger.

25. In a fuel pump unit serving a multicylinder direct injection internal combustion engine, said unit comprising a plurality of pumps each provided with a suction valve, a reciprocating actuating part, a driven plunger part and a resilient drive interposed between said parts, means for storing impulsion energy behind each such plunger subsequent to the closure of their respective suction valves, control means adapted to periodically release said energy behind the respective plungers, and adjusting means adapted to simultaneously alter the closure setting of all suction valves and thereby regulating the effective delivery from said pump unit to the engine.

26. In a fuel pump comprising a suction valve, a reciprocating actuating part, a driven plunger part and a resilient drive member interposed between saidparts, means lay closure of said suction valve and break for storing impulsion energy within said the pressure behind said plunger for emerdrive subsequent to the closure of the suction `genoy cut-out purposes. 10 valve, control means commanding the pump In testimony whereof, I have herewith I delivery, by` ass means for normally reguset my hand this 27th day of October, 1925.

lating the effgctive pump delivery, and sup-l e plementary regulating means adapted to de- LOUIS ILLMER.

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