US2408288A - Fuel injection apparatus - Google Patents

Description

Sept. l24,V 1946. A." T. BREMsI-:R

' FUEL; INJECTION APPARATUS Y Filed Nov. 13, 1942 a an@ Patented Sept. 24, 1946 l A2,408,288 FUEL INJECTION APPARATUS Albert T. Bremser, Sidney,` N. Y., assigner to Bendix Aviation Corporation, New York, N. Y.,

a corporationof Delaware -Application November 13, 1942, Serial'No. 465,448-

NT OFFICE'.

17 Claims.

.1 a rIhis invention relates to fuel injection apparatus and more particularly to means for controlling and effecting the delivery of fuel under pressure to the cylinder ofa solid fuel injection engine.

ness of said valve.

position.

stuck in closed position.

ing thereof is effected;

pended claims.

'5 One of the objects of the present invention is Referring to Fig. l, I0 is the' head of a cylto provide a novel fuel injection apparatus of inder of a solid fuel injection engine whereon is the type wherein an injection nozzle and a fuel mounted a novel fuel injection apparatus empump are embodied in a unitary structure. 4bodying the present invention, said apparatus Another object of the invention is to provide a l()v A'being preferably of the typecombining a fuel fuel injection apparatus having a pressure conpump and a fuel injectionv nozzle in a unitary trolled nozzle valve with novel means for prostructure. The injection apparatus, in the yform tecting said apparatus and thev engine on which illustrated, comprises a main barrel or housing the same is mounted in the event of inoperativei I` secured to cylinder head I by suitable means, such as bolts IIa or a clamp (not shown), so that A further object is to provide a fuel injection the lower end thereof extendsinto a recess I2 apparatus having novel means for preventing eX- formed in said cylinder head, A nozzle holder cessive fuel delivery in the event. the nozzle valve body I3 having an external'shoulder I4 formed controlling fuel injection becomes locked in open at the upper end thereof is mounted in the lower end of housing I I and is secured in operative po- Still another objectA is to provide novel'means sition by a gland nut i5 which screws into said in the above apparatus for preventing deleterious housing andY cooperates with said shoulder, a effects other than non-delivery. of fuel when the gasket IB being preferably interposed between pressure operated nozzle valve becomes lockedor Said shoulder and said gland nut. The latter iS effective to hold nozzle body I3 in abutting seal- A still further object is to provide a uniflow ing engagement With the lower face of a disc injector, i. e., aninjeetor having an injection member I-which,` in turn, bears against the lowerl nozzle and fuel pump embodied in e, unitary end 0f@ Dumpcyllder I8, and presses a shoulstructure, with novel means for eiecting adjustder ia formed on the latter into engagement ment of the nozzle valve s0 as to coni-,rol the 30 with an internal shoulderv in the bore of housing pressure necessary toeffect fuel delivery from AS a reSullkIiOZZle bOdy I3; dSC member l1 the nozzle. A Y and pump cylinder I8 are held against axial Still another object is to provide a fuelv inmovement and in fluid-tight engagement With jed-,ion apparatus having novel actual-,lng ,means each other, the latter two elements cooperating for controlling. the stroke of the movable pumpin aV manner more fully described hereinafter. ing element of said'apparatus. j Threaded on the lower end of nozzle holder A further Objectis to, provide a fuel pump embody I3 is a sleeve nut I9 which is provided interbcdying a novel arrangement for controlling the mediate its ends with'an internal shoulder 20 for :dowof fuel therein whereby advantageous ccolsupporting engagement with the flanged upper A Y 40 end 2 l'a, of a nozzle spray or. atomizing tip 2l, said The above and further objects andnovel fea-v tip having a central'bore' or duct 2lb therein and tures of the invention will more fully appearfrom a plurality ofM radially extending orifices 2 Ic adthe following detailed description whenthe same jacent the lower end thereof. 'The nozzle tip 2i is readin connection with the accompanying projects through the lower end `of sleeve nui-I9 drawing.v lIt is to be. expressly understood, how-A into the combustion chamber of'theengine cyleverthat.the'drawingV is for the purpose of'illusinder so that vfuel can be sprayed from orifices trationenly and is not intended as a definition of Zic into said chamber. The lower end of said nut the limits of theA invention, reference' for this fits into the lower endof recess I2, and anexlatter purpose being primarily had tothe apternal shoulder 22 formed adjacent said lower Y y a n 50 end seatson a gasket 23a which is, in turn, sup- In the drawing, wherein like reference charported by an internal shoulder 2.3.in said recess. acters refer to like parts throughout the vseveral Removably mounted in nut i9 above nozzle tip l 2|isa Valve guide 24i that is centrally bored for Fig. 1 is a sectional view, withV parts broken slidably receivingV the stem or piston portion of a away and'parts shown in-elevation, of one form of (Cl. 10S-41) 2. fuel injection apparatus embodying the present invention; and,

Fig. 2 is a fragmentary view of a fuel injection apparatus having amodied arrangement for controlling fuel delivery to the injection nozzle.

needle valve 25.. The bore through said guide member terminates at the lower or inner end of the latter in a small orifice 24a which is coaxial with passage 2lb, and a conical seat 25 is provided adjacent said orifice for cooperation with the tapered lower end of needle valve 25. The latter is thus effective to control the ow of fuel from member 24 into duct 2lb and hence into the engine cylinder. Preferably, the bore in guide member 24 is enlarged immediately above valve seat 26 to provide a fuel pressure chamber 2l through which a reduced portion of valve 25 extends. Fuel supplied under pressure to chamber 2l through a suitable passage 28 in member 24 in a manner hereinafter described acts against shoulder 29 formed on the valve by the reduction in the diameter thereof, and is thus effective to lift the latter off its seat and permit the flow of fuel from said chamber through passages 24a, 2 I b and 2 lc into the engine cylinder.

Valve is normally held in seated or closed position by novel means described hereinafter which apply a yielding pressure to the valve through a pressure pin or spindle 33 that freely extends through the central bore in nozzle body i3. The lower end of spindle or rod 30 is preferably recessed for freely receiving a pin 3| formed by a reduced portion at the upper end of valve 25, Between the adjacent ends of body i3 and valve member 2li there is preferably interposed a washer member or plate 32 having a central recess therein through which pin 3l of valve 25 extends, said washer being adapted to engage the upper end of the shank of the valve to limit the upward movement of the latter. A passage 33 extending from the upper end of body I3 conneots with passage 2B in guide member 24 through an orifice 34 in plate 32. The latter may be readily replaced if it becomes worn by the constant hammering of valve 25 thereagainst.

In order to deliver fuel under pressure to chamber 2l and thence to the combustion chamber, pumping means are provided, the same being preferably contained in housing il. As shown, said means comprise a plunger 35 slidably mounted for reciprocation in the bore of cylinder I8 so that a pressure chamber is formed at the lower end of said cylinder by said bore walls, said plunger and disc member il. A passage lla in disc il connects the pressure chamber to an annular groove l'ib provided in the lower face of said disc and said groove is adapted to overlap and open into the upper end of passage 33. One or more radial fuel inlet ports 35 are provided in the wall of cylinder I8 to connect said pressure chamber with an annular fuel supply groove 3l formed in the internal wall of housing il, plunger 35 operating as a slide valve to control the flow of fuel through said ports into cylinder I8 in a manner well understood in the art. In order that fuel from a suitable source may be employed in a novel manner to cool the fuel pump, the latter is novelly constructed with a pair of fuel passages 38 disposed in opposite sides of housing Il to connect with groove 3l. Fuel is admitted from the fuel source through one of said passages and may be discharged from the other so that, by delivering a quantity of fuel to the intake passage at a rate in excess of the amount used :by the engine, a continuous circulation of fuel may be maintained through said passagesand groove 3l te cool the parts adjoining the latter.

To control the point of fuel by-pass, i. e., the termination of fuel injection, a by-pass port 39 axially spaced above ports 36 is provided in member I8 for cooperation in a manner well understood in the art, with a helical groove 40 formed in the surface of plunger 35, said groove being continuously connected to the pressure chamber of the pump by suitable passages, such as con nected axial and radial passages 4l and 42, respectively. To vary the angular relation between metering groove 40 and cut-off or by-pass port 39 and thereby vary the effective pumping stroke of the piston, suitable means for angularly adjusting plunger 35 are provided and. in the form shown, comprise a sleeve 43 loosely surrounding the upper end of cylinder I8 in the enlarged interior of the upper end of housing ll. Gear teeth 44 are formed on the lower end of sleeve 43 for cooperation with a rack member (not shown) in a manner Well-known in the art. The upper end of sleeve 43 is axially slotted at 45 for slidably receiving a cross bar 4G rigidly connected to plunger 35. Sleeve 43 seats on an internal shoulder 4l in housing Il and is held against axial movement relative to cylinder I8 by a ring member 48 which engages an external shoulder on said sleeve and is positioned against an internal shoulder 49 in housing Il, said ring member being held on the latter shoulder by a spring 5i) which constitutes an element of the plunger reciprocating means. The latter comprises a tappet cup 5i which is slidably positioned in the upper end of housing Il for engagement with the head portion of a member 52 operatively connected to cr integrally formed with the upper end of vpiston 35. Downward movement is imparted to the latter by means comprising a rocker arm or tappet lever 53 which is pivotally mounted intermediate the ends thereof on a suitable rocker support 54 fixed to the cylinder head. One end of said arm bears against the upper end of tappet cup 5! and the other end is connected by a rod 55 to a cam follower 56, the latter being in operative engagement with the cam 51 which is adapted to rock said arm and actuate plunger 35 in a novel manner to be fully described hereinafter. The downward movement of said plunger is resisted and the upward movement thereof is effected by spring 50 which has the lower end thereof seated on ring member 48 and the upper end thereof engaging a washer 58', which, in turn, engages a downwardly facing shoulder formed -by the enlarged upper end of member 52 to transmit upward forces to plunger 35.

In the conventional fuel injection nozzle, the binding or locking of the nozzle valve in either .l open or closed position, or the clogging of the fuel passages, such as orifices 2|c, may produce serious detrimental effects, particularly at highl speed operation, which eects substantially diminish the life, efficiency and capacity of the engine. To minimize these deleterious effects to the fullest extent and prevent permanent injury to the engine or fuel injection equipment as a result thereof, novel means are provided in the above-described injection apparatus to insure safe operation. The novel safety means include mechanism adapted to relieve the pressure which tends to build up in the pressure chamber when nozzle valve 25 is locked in its closed position. For the latter purpose, the upper end of the bore of nozzle holder body I3 is preferably enlarged in diameter and receives the threaded upper end portion 30a of spindle 30 on which is mounted a spring supporting member 58, the latter having an internally threaded bore 59 whereby itis adjustably screwed on the end of said spindle.

Vchamber to unseat valve member 60. vto effect a fuel by-pass from the pump pressure Vslot 66 to fuel supply groove 31.

lia-toepas "siidably mounted in the upper Tend of the' bore 'the lower surface of saiddisc to normally close a central port`6I in said disc, said port connecting Withvthe pressure chamber of pumpV I8,y 35. A spring 62 is compressed between member V5&3 and valve member and normally maintains Vthe latter in operative engagement with disc I1,

said spring also applying the `downward pressure which yieldably pressesy valve into engagement with seat 26. p

'The diameter of port 6.1 is such that the area of valve member 60, which is subjected through Vsaid port to the fuel pressure inthe pump rpressure chamber, is less'than the effective area of valvev shoulder 279 which -is acted upon by the same fuel pressure. rAs a result, 'during normal '.operation, valve 25 has a greater totalu-pward force acting thereon for a given fuel pressure than the pressure on valve member 6 0 through port 6I so that the former is raised from its seat While the latter remains closed position. How.. ever, if valve 25 becomes stuck in closed position,

asufcient pressure is builtup -in the vpressure Inorder chamber in the latter event, one or more flutes or slots 63 are provided in the periphery of valve member EE which serve to connect the bore of i body I3 below said member with port 6I when said valve Amember is in open position. A radial passage 6d connects said bore to an axially extending slot 65 in the outer surface of flange I4 and said slot opens at its upper end through a Accordingly, when valve member 60 is inopen position, fuel is py-passed from the pressure chamber to the supply line or sumpy Novel means are provided for effecting adjustment of the compression of spring 62 to thereby control the fuel pressure necessary to raise valve 25 to open position. As shown, said means comprise a plurality of shims-61 located in the upper end of bore Y59 of member 58 so as to bear against -the end of threadedportion- 36a and thereby limit the extent to which the-latter can be threaded in said bore, By varying the number of shims lutilized in this manner, there is obtained an accurate control of the compression to which spring 62 is subjected. It is to'be noted that the pressure of said springen member 58`pre- 'vents the latter from unscrewing from portion a and vitiating a satisfactory adjustment once the same has been attained.

Y In order to guard'against detrimental effects of the locking Vor sticking of Valve 25 in open in broken lines in Fig. 1, ports 36 aswell as port 3.9 are closed and no fuel is admitted to the pres- `top dead ycenter position. A vmovement of the pump plunger, the piston' in 56 'holds plunger as in the desired stationaryposition. From point bto point c .of the cam surface,the remainder of the suction or up-stroke vof the plunger takes place, ports 36 being opened -duri-ng this portion -of the stroke and remaining open from points cto d when the plunger Yis in During this latter the engine cylinder is in the course ofl its compression stroke so there will be no danger of fuel being forced into the cylinder by the small pressure in the fuel supply line. At don thecam the plunger begins its power or down-stroke and reaches bottom dead center position when follower 56 engages lpoint e of the cam. Upon continued rotation of cam 51, the plunger moves upward until surface 1 -b, is again reached to complete the cycle. As a result of this novel construction of cam 51, fuel injection into the engine cylinder can take place -only during a predetermined part of the engine piston stroke even with the nozzle valve locked in Yopen position, Vso that the combustion chamber of the cylinder cannot be flooded with fuel oil.

In normal operation, when plunger is at ytop dead center position prior to the dovvn or power Y35 is closed. When-plunger 35 moves Ydownward to close inlet ports 36, the pressure lof the fuel in the pressure chamber is built up after the port closure and isV transmitted to chamber .-21, raising valve 25 and thereby permitting fuel to be yinjected into the combustion chamber of the engine cylinder through passages 2da, 2lb andr2lc. At

a further point in the down-stroke, metering groove d overlaps port 39 to connect the fuel supply line 31,l 3S with the pump pressure through passagesl 4I 'and t2 and fuel delivery is cut oif. After bottom dead center position is reached the suction stroke begins and continues until piston 35 reaches a point at which it closes ports 36 and port 39. At this point, plunger 35 comes to a standstill and remainsV stationary until a short time before fuel injection is desired. The upstroke is then resumed and the plunger completes its travel to top dead center position, filling the pump and nozzle pressure chamber with fuel at supply line pressure.

The pressure at which valve 25 opens to begin fuel injection to the combustion chamber during the power stroke of plunger'35- is readily predetermined by adjustment of the number of shims 61 inbore 55. y

If valve 25 becomes locked in closed position, the building up of fuel pressure in the pressure chamber unseats valve member andthe fuel from the pump pressure chamber is by--passed to the supply line through port 6 I, flutes 63, the bore of body I3, and passages 64, 65 and 66. If valve 25 becomes locked in open position, the delivery of fuel to the combustion chamber in excessive vsure chamber and, therefore, nonecan oW to the combustion chamber of the engine cylinder. Plunger 35 is maintained in this position by cam j 51 for a substantial portion of the period between fuel injections. To accomplish this, said cam, which rotates in the direction of the arrow, has a. circular contour for a substantial part of its peripheral. surface, i. e., betweenpoints a and b, which contour when in engagement With-followerl quantities is prevented by plunger 35 which closes ports 3-6 and 39 for a substantial period between'v y fuel injections.

The flow of fuel in the supply system through groove 31 is continuous, the same entering said groove through one passage 38 andv leaving through the oppositely disposed passage 38. The amount of excess fuel circulated in this` manner may be regulated in accordance withthe need for cooling the apparatus.

A modification of the abovefdescribeduni'ow injection apparatus is shown in Fig. 2, wherein a conventional type cam actuates the plunger and novel means in the nozzle holder body guard against the deleterious effects of the locking of nozzle valve 25 in either open or closed position. As shown, the apparatus comprises a nozzle holder body 10 operatively mounted in the lower end of housing II by means of a gland nut I5, sleeve nut I9 being secured to the lower end of said body and carrying guide member 2li in which is mounted nozzle valve 25. A washer member 1I is held between the lower end of said body and the upper end of said guide member and has a central recess through which pin 3l of valve 25 extends. Body 18 is provided with upper and lower axial recesses or bores 12 and 13, respectively, which are connected to each other by a port 14. A passage 15 connects bore 12 with an annular groove 16 formed in the lower end of body 10 and said groove communicates with a groove 11 in the upper end of valve guide member 24 by means of one or more passages 18 in washer member 1I, groove 11 being in turn connected to the upper end of passage 28. Bore 13 is preferably connected by a passage or series of passages 18 to the upper end of body 10 and, accordingly, opens into fuel supply groove 31.

A delivery valve adapter unit 18 having an external flange 19a formed thereon at the upper end thereof is mounted in the upper portion of bore 12 and flange 19a is pressed tightly between a gasket 10a and the lower end of cylinder I8, said gasket fitting into an annular indentation in the upper end of body 18. The central bore of said adapter opens into the pump compression chamber and a retraction type delivery valve 80 is slidably mounted in said adapter bore to control the fuel ow from said chamber to bore 12. The upper end 85' of said delivery valve is adapted to engage a conical seat 8l in said adapter bore and a cylindrical portion 88a is formed at the lower end of said valve for fluid-tight engagement with the internal walls of adapter 19. An annular groove 88h is provided between the upper end yof portion 88a and axial flutes 88o, said flutes connecting at the upper ends thereof with a chamber 82, which is formed immediately below seat 8l by an enlargement of the adapter bore. A spring' 83 disposed between the bottom wall of bore 12 and a shoulder 88d formed on valve 80 yieldably urges the latter upward and normally maintains said valve in closed position. When a suiiicient pressure is built up in the pressure chamber of the pump I8, 35 to lift said valve from seat 8l and withdraw portion 88a from the adapter bore, the pressure chamber is open .to bore 12 and :the fuel pressure therein is transmitted .to Valve 25 through passages 15, 18' and 28. Thus, even if valve 25 is locked in open position fuel delivery to the engine cylinder can occur only when the sufficient pressure is built up in the pressure chamber to move delivery valve 80 to open position.

Novel means are also embodied in body 10 for yieldably urging valve 25 into engagement with its seat and for preventing any serious detrimental effects when said valve becomes stuck or otherwise inadvertently locked in closed position. In the illustrated embodiment, said means comprise a pressure transmitting element 84 disposed in the lower end of bore 13 and loosely mounted on the upper end of pin 3l so as to transmit downward forces to the latter. An upwardly facing shoulder 84a is formed on said element and the lower end of a spring 85 seats on said shoulder and is centered by the shank of said element, said spring being held under compression between said shoulder and a Valve mechanism in the upper end of bore 13 so that valve 25 is pressed in the direction of its seat. Said mechanism comprises a screw member or stud 81 having a flange 81a formed at the base of the head thereof for engaging the upper end of spring 85, said head serving as a centering guide for said spring. Screw member 81 is threaded into the lower end oi a valve member 88 which is slidably mounted in bore 13 and has a needle valve element 88a integrally formed with or otherwise rigidly secured to the upper end thereof. The lower end of port 14 is flared to form a conical seat which cooperates with valve element 88a to normally prevent fuel flow through said port into bore 13. A plurality of axial grooves or flutes 88h are formed in the periphery of valve member 88 to interconnect the upper and lower ends of said bore so Ithat passage 18 communicates with bore 12 when valve 88a is open.

The cross-sectional area of port 14 is such that the total effective fuel pressure acting downwardly on valve 88 is less than the total pressure acting upwardly on valve 25 so that in normal operation valve 88 is always closed and valve 25 is opened periodically in response to the pressure created by the pump to permit fuel delivery from bore 12 to the combustion chamber of the engine cylinder. However, in the event valve 25 becomes locked in closed position, the pressure in bore 12 will, during the effective pumping stroke of the pump plunger, cause valve 88 to open so that fuel is by-passed from said bore through port 14 to bore 13 and from the latter bore back to .the fuel supply line via passage 18.

In order to control the compression of spring and, therefore, the fuel pressure at which valve 25 will be lifted from its seat. a plurality of washer-like shims 89 are disposed between the upper face of shoulder 81a and the lower end of member 88. The axial position of screw member 81 can be accurately adjusted by varying the number of shims 89 and thus provides accurate means for regulating the pressure exerted by spring 85.

There is thus provided a novel fuel injection apparatus of the uniow type wherein a fuel pump and a fuel injector are combined in a unitary structure. The apparatus embodies novel means for insuring .against any permanent or serious deleterious results in the event the nozzle valve is bound or otherwise locked against movement either in open or closed position. Novel means are included for preventing excessive fuel delivery to the engine cylinder when the nozzle valve is in open position as well as novel means for relieving the pressure built up in the pump compression chamber when the nozzle becomes clogged or the nozzle valve remains closed during operation. There is also provided a novel arrangement whereby the nozzle valve operation can be controlled, i. e., whereby the fuel pressure at which the valve will be lifted from its seat can be accurately predetermined during assembly of lthe injector.- Additionally, the novel structure provided includes means whereby cooling of the same may be effected in a novel manner. Still another novel feature of the pump and nozzle unit provided is the location of the by-pass port above the inlet port of the pump to insure against any accumulation of air in the pump compression chamber.

Although only two embodiments of the invention have been illustrated and described. it

isV to be expressly understood that the same is not limited thereto. For4 example-,fit will now be` apparent to those skilled in'theart that other types of delivery valve units may be employed in the embodiment of Fig. 2, that insteadiof `a single spring, separate springs may be employed for normally maintaining safety valve fill or 88 and `nozzle valve 25 in closed position, :and that by-pass port 39 may be connected to any lowv pressure space other than the supplyline 3l, 38. It is to be understood also thatthe nozzle safety valves and adjusting mean-s shown in Figs. V1 and 2` for relieving the fuel vpressure in the pump pressure'chambers may bev interchanged. Various other changes mayy also be made in the design and arrangement of'parts illustrated with. out departing from the spirit and scope of the invention. For a denition of the limits ofA the invention, reference is had primarily to the ap pended claims.

What is claimed is 1. In fuel injection apparatus of the class described, pump means comprising a casing, a cyl-Y inder in said casing andy areciprocating plunger in said cylinder, said cylinder Vhaving port means controlled by said plunger and connecting the interior of the cylinder with an annular space between said casing and cylinder, said space having an inlet and an outlet independent of said ports whereby fuel may be circulated therethrough irrespective of the position of said plunger and said space being the sole connection between said inlet and outlet when said port means are closed by the plunger.

2. In fuel' injection apparatus, pump means comprising a casing, a cylinder in said casing' said cylinder and casing cooperating to form an annular space therebetween having an inlet and an outlet through said casing, and a reciprocating element in saidcylinder for controlling communication between said space and the interior of said cylinder through ports in the walls of said cylinder, said space being annular where'-r by fuel may be continuously circulated around said cylinder irrespective of the position of said element and said space being the sole connection between said inlet and outlet when said port means are closed.

3. In apparatus of the class described, fuel pumping means for an internal combustion engine, a first valve means responsiveto pressure created by said pumping means for controlling the llow of fuel from the pressure chamber of said pumping means into an engine cylinder, a second valve means responsive to said pressure for controlling the flow of fuel from said pressure chamber to a point outside said cylinder, said first valve means being adapted to open in response to a lower pressure than said second valve means, and a single resilient means for normally holding both said valve means in closed position, said first and second valve means being in axial alignment with each other and with said pumping means.

4. In apparatus of the class described, fuel pumping means for an internal combustion engine, a rst valve'means responsive to pressure created by said pumping means for controlling the iiow of fuel from the pressure chamberl of said pumping means into an engine cylinder, a second valve means responsive to said pressure for controlling the flow of fuel from said pressure chamber to a point outside said cylinder, said first valve means being adapted to openin response to a lower pressure than saidsecond 10 valvexmeans, and common yieldable meansfor normally holding said rst andi second valve meansin closed position.

5. fuel injection apparatus for internal combustion engines, means forsubjecting aliquid fuel to pressure for forcing the same into the cylinder'of an. internal combustion engine, a first valve means'responsive-to the pressure of said'fuel for controlling `the flow of fuel into said cylinder, a second valve means responsive to the pressure of said fuel for controllingthe low of said fuel 'to ay pointfoutside said cylinder, and common means lfor yieldably biasing said first and second valve means toward closed position, the effective area of said Second valve means acted upon by said fuel pressure being less than the `corresponding area of said rst'valvemeans when both said valve means are in closed position.

6. In apparatus of the class described wherein liquid lfuel is supplied under pressure @by a fuel pump, the combination of, a valve responsive to fuel pressure created by said pump forcentrolling the flow .of fuel through an orifice, valve means for relieving the pressure in said pump when said valve fails to open in response toa predetermined maximum pressure, and common resilient means interposed between said valve and valve, means for normally holding the same in closed position.

,'7. In apparatus of the class described, a fuel pump comprising a cylinder having inlet and by-pass ports therein, a plunger in said cylinder for controlling the flow through said ports, and means for periodically reciprocating said plunger, said last-named means` being operable to cause said plunger to close said ports during at least a major portion of the interval between the beginning of successive cycles of operation of said plunger. Y

8; In fuel'injection apparatus for an internal combustion engine, pump means, means con-y nectingr the pressure chamber of said pump means to a source of fuel supply, means connecting said chamber to the cylinder of an internal combustion engine, said pump means comprising means for controlling said first-named connecting means, and means for cyclically operating said controlling means to cut ofi communication between said chamber and source during at least a major portion of the interval between the beginning of successive cycles of operation` of said controlling means.

9. In fuel injection apparatus, a cylinder, a plunger mounted for reciprocation in said cylinder and defining a pressure chamber therewith, means for supplying liquid fuel to said chamber, vmeans for delivering fuel from said chamber to a combustion chamber, said last named means including a pressure responsive control valve, and means for actuating said plunger so as to maintain said plunger stationary for a substantial portion of the duration'of each suction stroke thereof, said plunger in the stationary position thereof being effective to cut oif communication between said rst named means and the pressure chamber.

10. In fuel injection apparatus, fuel pumping means adapted to periodically apply pressure to a quantity of fuel, means comprising a delivery line from said pumping means to an engine compression chamber, a pressure responsive valve normally maintaining said delivery line closed, said valve being moved to open position by the building up of fuel pressure in said line, means comprising a by-pass passage for relieving the pressure in said delivery line, a valve responsive to the pressure of the fuel for controlling the ilofw of fuel through said passage, and common resilient means for normally holding both of said Valves in closed position, said second-named valve being moved to open position only when said first-named valve is closed and a pressure in excess of that necessary to normally open said first-named valve is built up in said delivery line.

l1. In fuel injection apparatus, a cylinder, a plunger mounted for reciprocaticn in said cylinder and defining a pressure chamber therewith, at least one fuel supply port communicating with said pressure chamber, a pressure responsive control valve adapted to regulate the fuel discharge from said chamber, and means including a cam for actuating said plunger, said cam main,- taining said plunger stationary for the greater portion of the duration of each complete stroke cycle thereof at a point in the suction stroke when said plunger closes said port.

12. In apparatus embodying a fuel pump, means comprising a delivery passage adaptedto deliver fuel from said pump to a discharge orifice, a control valve actuated by the fuel pressure in said passage to open the latter for fuel discharge, a delivery valve operatively associated with said pump to control the fuel delivery to said delivery passage, a by-pass passage connected to said delivery passage at a point between said delivery and control valves, and a by-pass valve normally closing said by-pass passage, said last-named valve being moved to open position by the fuel pressure in said delivery passage when said pressure exceeds the pressure normally necessary to actuate said control valve to open position and all of said valves being co-axial with each other and with said pump.

lf3. In fuel injection apparatus embodying a fuel pump, means Comprising a delivery passage adapted to .deliver fuel from said pump to a discharge orifice, a control valve actuated in one direction by the fuel pressure in said passage to open said orifice for fuel discharge, a by-pass passage connected to the pressure Chamber of said pump, a by-pass valve normally closing said bypass passage, said by-pass valve being movable in the opposite direction to open position by the fuel pressure in the pump pressure chamber when said pressure is in excess of that necessary to move said control valve to open position, and common resilient means interposed between said valves for normally holding the same in closed position.

1li. In injection apparatus of the uniow type having a housing and pumping means in said housing including a cylinder and a plunger, a fuel supply chamber in said housing surrounding said cylinder and adapted to be connected periodically with the pressure chamber of said pumping means, and means including a pair of passages disposed on opposite sides of said housing so as to connect with said chamber for continuously circulating fuel through said chamber at a rate exceeding that necessary to feed said pumping means, said chamber being the sole connection between said pair of passages.

15. In apparatus of the class described, a fuel pump comprising a cylinder having inlet and by-pass ports therein, a plunger in said cylinder for controlling the flow through said ports, means for periodically reciprocating said plunger, said last-named means being operable to cause said plunger to close said ports during at least a major portion of the interval between the beginning of successive cycles of operation of said plunger, a first valve means responsive to pressure created by said pump means for controlling the flow of fuel from the pressure chamber of said pump means into an engine cylinder, and a second valve means responsive to said pressure for controlling the ow of fuel from said pressure chamber to a point outside said engine cylinder, said rst valve means being adapted to open in response to a lower pressure than said second valve means.

16. In fuel injection apparatus of the class described, a pump casing, a pump cylinder in said casing, a reciprocating plunger in said cylinder, a tubular nozzle holder body extending into said pump casing in axial alignment therewith, means for securing said cylinder and nozzle holder body in said pump casing, an adaptor interposed between said nozzle holder body and said cylinder, a delivery valve operable in said adaptor for controlling the flow of fuel from the pressure chamber in said cylinder to said nozzle holder body, means for supplying liquid fuel to a space in said pump casing around said cylinder, means including a by-pass valve in said nozzle holder body for connecting the interior of said nozzle holder body to said space, a control valve for controlling the flow of fuel through said nozzle holder body to a combustion space, and common resilient means interposed between said by-pass valve and said control valve for normally holding the same in closed position.

17. In fuel injection apparatus of the class described, a'fuel pump comprising a casing, a cylinder in said casing and a reciprocating plunger in said cylinder, a nozzle holder body, means for securing said nozzle holder body and said cylinder in said pump casing in axial alignment with each other, a pair of valves in said nozzle holder body adapted to be moved to open position by the fuel pressure created by said pump, one of said valves being a control valve adapted to normally control the flow of fuel to a combustion space and the other being a by-pass valve adapted to control the flow of fuel to a region of low pressure for relieving the fuel pressure in said cylinder and holder body whenever said control valve fails to open in response to a predetermined maximum pressure, and common resilient means interposed between said valves for normally holding the same in closed position.

ALBERT T. BREMSER.

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