US2280248A - Regulating pump - Google Patents

Description

L dill 2f April 2.1, 1942- s. MEgswlNKEL 2,280,248

REGULATING PUMP lNVEfNTORf SAMUEL MEIWINKEL ATTRNEJ/s S. MEISWINKEL REGULATING PUMP Filed Jan. 17, 19:59

Apil 21, V1942.

2 sheets-S115@ 24 INVENT' OR. AML/EL-J MEJwINKL-:L

M AML ATTO'RNEG `Patented Apr.721, 1942 n lan(iULAnING PUMP Samuel Meiswinlrel, Gaggenau, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany .Application January 17, 1939, Serial No. 251,326

i In. Germany January 22, 1938 35 claims. l (c1. 12s- 140) This invention relates to an apparatus for `limiting the maximum speed of injection internal combustion enginesv by regulating the fuel feed,

and has for itsobject to'effect in a'very simple manner andi without separate mechanical or pneumatic auxiliary equipments, a reliable and accurately operating control of the internal combustion engine for the purpose of limiting its maximum speed of rotation.

For limiting the maximum speed of `injection internal 'combustionengines by the regulation of the fuel feed, a constant factor and a variable factor are, according to the invention, brought into alternating relationship in such amanner that when the constant factor is exceeded, the fuel feed to the cylinders is reduced by the variable factor, the variable factor being a function of the speed ofrotationof the engine; The said variablefactor is determined by the quantity of fuel flowingback from the pump cylinder per unit of time andincreasing as the speed of rotation increases. The quantity of lfuel flowing `back per unit of time acts directly or indirectly on the adjustment of a slide valve controlling the feed passages, the returning fuel and the fuel fed from the tank beingjbr'ought together each from `one side of the slide valve, so that when a certain speed is attained a dynamic pressure is produced which constitutes the means for controlling thefuelfe'ed.`

For carrying out the objects of this invention, a `fuel pump with controlled commencement of feed and constant end of feed `is used so that the injection adjustment is automatically coupled with the quantitybf fuel fed,xtha`t` is, retarded ignition takes place at low load and a small quantity fed, and `advanced ignition at heavy load which approximately corresponds `to the maximum speed. The arrangement is such that the `controlling element on the one hand is underthe influence of the constant factor and on the other `hand underthe `influence of the variable factor which on exceeding the constant factor* adjusts the controlling element and throttles the fuel feed by `changingthe passage cross-sectional area. -For this `purposea controlling element `The controllingelement may consist of one or several rotary slide valves `to which the fuel from the tankws freely iromoue side but from J the other side (by-pass-fuel) through anozzle which is arranged in such a manner that,when a predetermined feed is exceeded dynamic pressure lis produced on the inlet side of the `nozzle and adjusts the controlling element. The throttling device may be constructed as a nozzle with adjustable throttling cross-section. 'I'he controlling element itself is, according to the invention, arranged as a rotatable or axially shiftable piston-shaped slide valve in the induction conduit, and has on its periphery'one or more controlling apertures or controlling edges which at the adjustment of the slide valve alter by throttling the passage cross-section of the conduit, i. e. the quantity of fuel sucked by the pump. The controlling apertures orfedgesof the slide valve are at the same time preferably constructed as peripheral tapered grooves or ports varying in depth, which control the inlet bores or channels leading to the pump.

The invention also` relates to-a device for adjusting the individual pump pistons for the purpose'of compensating inaccurate machining. A

' This independent adjustment is rendered possible, according to the invention, in that the feed pistons,each provided inan upper portion with a bevelled `edge, and which are not rotatable when running, are turned when adjusting the pump, for example on the test bench, and xed in the position which has been found to be correct, so that the necessary quantity delivered by these pistons can be very accurately controlled in each case. The adjustment is effected, for example, by means of a` toothed.r sector rigidly connected with the piston and which allows of an adjustment through a 4very small angle. Thus, the bevelled edge of each piston is adjusted relatively to the admission channels in such a manner that the commencement of feed` of the individual pistons can be accurately determined independently of each other. The pistons are secured in the determined position, for example from the exterior, by means of a set screw which locks the toothed sector and consequently the piston rigidly connected therewith.

. This adjustingdevice possesses the advantages that unavoidable inaccuracies in machining can be compensated in a simple manner when the pump is Vbeing adjusted, andthat the adjustment can be carried out in a short time from the outer side without any fitting work being necessary.

`The invention also relates to such a construction of the pump cylinders which enables them to be produced and machined in a particularly simple and @heap mann-er'- According to the invention, the casing having the bores and passages is made of cast-iron, preferably cast pig iron, and the cylinder bores and also the passages controlled by the piston are bored in separate rigidly inserted liners made of high grade material. The liners made for example of steel are cast, pressed or shrunk into the casing as a solid body before the different holes and passages are bored. The advantages are thus obtained that the machining is extremely simple and the position of the bores and control edges is always accurate.

Several embodiments of the invention are illustrated diagrammatically by Way of example in the accompanying drawings in which:

Fig. 1 is a section through the fuel feed pump taken on line 2--2 of Fig. 2 and viewed in the direction of the arrow;

Fig. 2 is a section on line I I of Fig. l;

Fig. 3 is a top plan view in section on line 3--3 of Fig. 2;

Fig. 4 is a sectional detail view showing an adjustable throttling nozzle;

Fig. v5 is a section through a pump cylinder with adjusting device for the feed piston;

Fig. 6 is a top plan View in section on line 4--4 of Fig. 5; and

Fig. 7 is a section through a pump cylinder with a liner.

The fuel pump Il) has an inlet passage Il and a return passage I2 which are connected the one with the other by a channel I3. Pump pistons I5 are arranged in'the cylinder bores or spaces I4 and moved by suitable cams of a cam shaft slide valve I9 in the form of a piston-shaped '1in hollow sleeve provided at one end with a nozzle or throttle opening 20 moves in the inlet passage I I. The stroke of the slide valve I9 is limited on the right by an adjustable stop screw 2i and on u the left by an adjustable stop 22. The arbitrary 5 control of the internal combustion engine is effected through the intermediary of the accelerating lever (not shown) which turns the piston I5 or the edge 23 thereof through the regulating or `adjusting device 24.

The fuel flows from a container, not illustrated, through a conduit 25 and the openings 46, that is from the side remote from the nozzle 20, to the slide Valve I9. The piston I5 controls by suitably shaped edges the admission channel I'I and the overflow channel It in such a manner that the y fuel is forced through the conduits 26 into the cylinders of the internal combustion engine, and

after having performed part of a predetermined stroke, a uniform quantity of fuel is fed through the piston bore 2'I and the recess 28 into the overflow channel I8 and thence into the return passage I2. The slide valve I9 has tapered grooves 29 and openings or bores 30 in its walls, which,

together are arranged to form ports registeringv with the channel I'I and act in such a manner that the effective cross-section of the inlet passage II leading to the cylinders I4 can be altered.

The operation of the regulator is the followings.

When the internal combustion engine and conr sequently the pump shaft I6 are running at a low` speed, a quantity of fuel corresponding to the stroke space is sucked into the cylinders I4 as the piston I5 descends and is injected into the cylinders of the internal combustion enginel i bustion engine.

through a suitable delivery passage at the correct time during the ascent of the said piston. As soon as the recess 28 reaches the overflow channel I8, the excess fuel ows back through the channels I2 and I3 into the inlet passage II from which it is again sucked into the cylinders. At the same time the spring 3l presses the slide valve I9 towards the left, so that the conical grooves 29 expose the largest passage cross-section to the cylinders I4. If the speed of the internal combustion engine increases and attains a predetermined maximum, the quantity of fuel iiowing back in a unit of time is so high that at the throttle point 20 counter pressure is produced which shifts the slide valve I9 towards the right in overcoming the force of the spring 3| and the pressure of the fuel within the passage II, and reduces the effective cross-section of the passage I I to the pistons I5 corresponding to the reduction in cr-oss-section of the tapered grooves 29. Thus, the charge in the cylinder spaces I 4 during the descent of the piston Will be reduced and a correspondingly less quantity of fuel will be injected into the cylinders of the internal com- The by-pass quantity per piston stroke remains the same at all speeds. Owing to the drop in pressure which then occurs in the by-pass conduit a slight oscillation of the regulating slide Valve I9 will take place until this valve has formed relatively the smallest possible feed cross-section of the entrance to the admission channels I'I necessary for the maximum noload speed.

Fig. 4 shows a form of construction in which the throttle 23 can be varied in cross-section by a needle 32.

According to the form of construction illustra-ted in Figures 5 and 6, the pump pistons I5 are pressed tightly against the cams 35 of the fuel pump shaft I6 by springs 33 which bear at one end against a spring washer 34 and at the other end against a spring Washer 35. The pistons I5 have milled faces 31 on to which the slotted toothed sectors 38 can be slipped from the side. These toothed sectors 38, which are nonrctatable on the pistons but longitudinally shiftable thereon, are fixed by suitable locking devices shown as set screws 39 from the outer side. By turning the toothed sectors 38 the bevelled edges 23 of the pistons I5 are adjusted relatively to the admission channels I'I, and consequently the quantity delivered by the individual pistons can be regulated independently the one of the other. The pistons I5 also have recesses or grooves 29 and bores 21, through which the excess fuel can flow off through the overflow channels I8 to the return passage I2. The channels I'I and I8 are closed at their outer ends by plugs 43 and 4I, respectively.

According to the example illustrated in Fig. 7, the cylinders d2 in which the pistons I5 move, are constructed as steel liners 43 which are cast, pressed or shrunk into the casing I0, for example a pig iron casing. The casing may be made of light metal and produced for example by diecasting. The liners 43 are preferably inserted in the casing as solid bodies before the different holes and passages are bored (admission channel I1, overflow-channel I8' and so forth). Thus, the machining of the liner 43 is simplified considerably, the edges of the channels I1 and I8 will be accurate and the resistant material sharp, so that the timing remains constant even after long service. It is evident that the liner d may be made not only of steel but also of brass or offother suitable material. VVThe pistons l5 `haverollers 43 `which are-pressed against the camsl3i `by springs IM.I Thesprings bear'atone 4end against spring washers 451 and `at the other endagainst the`c`asingl. i V e While thepumps described aboveand illustrated in vthe drawings are particularly `adapted foruse in providing a` limited maximum e fuel @feed to internal combustion engines, -it will be obvious vthat vin, the `broad sense such pumps are of `general application wherever `a limited maximum output of' pumped liquid is desired.` i

It will therefore be seenthat I have provided a construction which satisfies thebbjects enu-` merated above and one which constitutes a valuable advance in the art.` While'I have vshown the invention in certain physical embodiments, it isfto,` beI understood `that modifications of the structure shown maybe made by those vskilled inthis artwithout departing from my invention as expressed in `the claims which follow.

WhatI claimis: y l; Afuel pump comprising a pump casingprovided separate pump cylinder spaces, a

commonfinlet passage provided with ,channels leading to the individual "spaces, a `return pasage provided with channels leading from said spacesia fuel controlling element in the said inlet passageresponsive tothe pressure of the fuel in said returnpassage, and a tnrottlingf` device arranged between. the return passage,` and theinlet passage. i

element in both directions. e i 3. A fuel pump comprising a pump casing pro` vided with separateQpump cylinder spaces, a common inlet passage provided with channels leading tothe individual spaces, a return passage provided with channels `leadingfrom said spaces, `a piston-shaped hollow sleeve in said inlet passage having a throttle opening in the wallnof said pistonto form aconnection between the inlet and `return, passages,` said piston being subjected to the pressure of the fuel within said return passageeand said sleeve as a whole being` axially shiftable in the inlet passagev under `the actionof such` pressure, the walls, of said sleeve beingprovided With-throttle openings connecting the interior of saidsleeve with the channels leading to the cylinder spaces, and spring mean for biasing said sleeve one direction.

' 4; Fuelfeed controlling apparatus for internal combustion engines comprising, in combination, a device includinga pump cylinder space, an

inlet passage leading `to said cylinder space, a

delivery passage leading from said cylinder space, a return passageleading from said cylinder space to said' inlet passage, andthrottling means intermediate said return and inlet passages for main- A i "lo taining @the pressure of the` fuel in said return passage substantially proportionate to fthe amount of fuel flowing back to said return passage`,"and means responsive to said pressure for varying the delivery of fuel to the engine. 5L Fuelfeed `coritrollingapparatus for internal combustionengines comprising, in combination, `a device including a pump `cylinder space, a

` source of fuel supply for saidcylinder space, a

delivery passage leading from said cylinder space, a return passage leading from said cylinder space to saidv source of fuel supply,` and throttling 1 means intermediate saidr return passage and said source of fuel supply formaintaining the pressure of the fuel insuch return passage substantially proportionate to'the yamount of` fuel flowing back through said return passage, and means responsive to" said pressure for varying the delivery ofV fuel tothe engine. i

, 6. Fuel feed controlling apparatus forinternal combustion engines comprising, in combination, a device including a pump cylinder space, an

inlet passage` leading thereto, a delivery passage leading therefrom, a return passageleading from said cylinder space to said inlet passage, means for establishing a pressure differential between said inlet and return passages, means responsive to said pressure differential for controlling the delivery of fuel to the engine, and spring means lfor biasing said controlling means. i

7. A fuel pump, comprising,.in combination, a pump casing including a cylinder space,` an inlet passage, a canal leading to the cylinder space, a delivery passage leading from the cylinder space, a return passage connected to thecylinder space, and a regulatingdevice for controllably interconnecting said inlet passage with said canal, said regulating device being subjected to and movable by the pressure of the fuel `in said return passage,

fand' being provided with a throttle opening interconnecting said return passage with said inlet 8. The combination according to claim 7, in which said regulating device includes a hollow sleeve having transverse bores interconnecting `said inlet passage with said canal.

9. The combination according to claim '7, in which said regulating device is in the form of an axially adjustable `slide valve.

10. The combination according to claim 7, in

which said regulating device includes a hollow sleeve closed at one end to form a piston face subljected to the pressure of the fuel in the return piston face.`

passage, said sleeve having `transverse bores interconnecting said inlet passage with said canal, said thirottle opening extending through said l1. A pump comprising., incombination, a pump casing having separate pump cylinder spaces, a common `inlet passage,` canals leading from said passage to individual cylinderspaces, a

common return passage, other canals leading from said `cylinderspaces to said return passage,

and a controlling device in said inlet passage having `throttling openings adapted to adjustably control the communication 4between said inlet passage land the` canals leading to the cylinder spaces, said device including means responsive -"to the pressure in said return passage for varying the effective `cross-section of said communicating v65 openings. i e

12. A liquid pump comprising in combination,

' a cylinder casing having at least two pump spaces and pistons in said spaces, eachpiston having a beveled control edge, meansfor adjusting each piston independently ofthe other, a com-mon inlet passage leading to said cylinder spaces, a return passage leading from saidcylinder spaces to said inlet passage, throttling means `intermediate said return and inlet passages for` maintaining the pressure of the fuel in said return "passage sub- 14. The combination according to claim 12,

in which said independent adjusting means includes a toothed sector, longitudinally shiftable upon but non-rotatably connected to each piston, and a locking device engaging the toothed sector. p

15. The combination according to claim 12, in which said independent adjusting means includes a toothed sector, longitudinally shiftable upon but non-rotatably connected to each piston, and

a set screw adjustable from without said pump casing, engaging with the teeth of the toothed sectors.

16. The combination according to claim 12, in

which said pump casing is formed from cast iron and said cylinder spaces are provided with smooth liners of another material.

17. The combination according to claim 12, in which said pump casing is formed from cast iron and said cylinder spaces are provided with steel liners.

18. The combination according to claim 4, in combination with a` pump piston in said pump cylinder space, and means for maintaining the amount of fuel returning to said return passage substantially constant per working stroke of said piston.

19. The combination according to claim 4, in combination with a pump piston in said pump cylinder space, anda control groove Xed on said piston, communicating with said cylinder space and opening and closing said return passage at a constant point of time during the stroke of the pump piston to maintain the amount of fuel returning to said return passage substantially constant per working stroke of said piston.

v20. The combination according to claim 4, in combination With a pump piston in said pump cylinder space, said piston being provided with a control edge oblique to the axis of said piston for controlling the connection between said inlet passage and said cylinder space, and with a control groove extending substantially perpendicularly to the axis of said piston for controlling the connection between said return passage and said cylinder space, and means for rotating said piston, whereby the time relationship of the control of the connection between said inlet passage and said cylinder space may be varied while that of the control of the connection between said return passage and said cylinder space remains substantially constant per working stroke of said piston.

21. The combination according to claim 4, in which said last means decreases the amount of fuel owing to the engine upon an increase of presure of the amount of return fuel.

22. In a iluid pump including at least one pump cylinder space having a piston therein, an inlet passage connected to said cylinder space, a delivery passage leading from said cylinder spa-ce, a return passage leading from said cylinder space, and regulating means in said inlet passage responsive to the pressure within said return passage for varying the amount of fluid supplied to said cylinder space.

23. The combination according to claim 22, in which said regulating means includes a slide valve mounted for reciprocal movement in said inlet passage.

24. In a fluid pump including at least one pump cylinder space having a piston therein, an inlet passage connected to the cylinder space, a delivery passage leading from the cylinder space, a return passage leading from said cylinder space to said inlet passage, and regulating means in said inlet passage responsive to the pressure differential between said inlet and return passages for varying the amount of fluid supplied to said cylinder space, said regulating means including means intermediate said return and inlet passages having an interconnecting throttling bore for establishing a pressure differential between said inlet and return passages.

25. In a uid pump including at least one pump cylinder space having a piston therein, an inlet passage connected to the cylinder space, a delivery passage leading from the cylinder space, a return passage leading from said cylinder space to said inlet passage, and regulating means in said inlet passage movable in one direction or the other in accordance with the diierence in pressure within said inlet and return passages for varying of the amount of iiuid supplied to said cylinder space, said regulating means including means intermediate said return and inlet passages having an interconnecting throttling bore for establishing a pressure differential between said inlet and return passages.

26. The combination according to claim 25, in combination with spring means for opposing movement of said regulating means by the pressure within said return passage.

27. In a uid pump including at least one pump cylinder space having a piston therein, an inlet passage for said cylinder space, a canal in said pump, opening into said inlet passage and said cylinder space for conducting fluid to the latter from said inlet passage, a return passage leading from said cylinder space to said inlet passage, and an axially shiftable slide valve movable in one direction or the other in accordance with the difference in pressure Within said inlet and return passages for varying the ow of uid from said inlet passage to said canal. said slide Valve including means intermediate said return and inlet passages having an interconnecting throttling bore for establishing a pressure differential between said inlet and return passages.

28. In a fluid pump including at least one pump cylinder space having a piston therein, an inlet passage for said cylinder space having a canal leading to said cylinder space, a delivery passage leading from said cylinder space, a return passage leading from said cylinder space to said inlet passage, and an adjustable hollow slide valve open at one end, axially sliiftable Within said inletl passage and having a radial opening therethrough interconnecting said canal with the hollow portion of said slide valve for controlling the flow of fluid from said inlet passage to said cylinder space, said slide valve being mov able in one direction in accordance with the pressure within said return passage, said slide valve including means intermediate said return and inlet passages having an interconnecting throttling bore for establishing a pressure differential between said inlet and return passages.

29. The combination according to claim 28, in

pump cylinder space having a piston therein, an y inlet passage leading to said cylinder space and having a` controlling canal, a hollow slide valve axially shiftable within said inlet passage for varying the effective cross-sectional area of said canal, provided with an opening from its outer surface to the interior hollow portion for inter connecting the latter with said canal, and hav ing one end in communication with said inlet passage and the other end with `a throttle open ing therethrough leading from said inlet passage, a delivery passage leading from said cylinder space, and a return passage *for guiding fluid under pressure from said cylinder space against the end of the hollow slide valve provided with the throttle opening.

31.'In a fluid pump including at least one pump cylinder space havingia piston therein, an inlet passage having an opening into said cylinder space, a hollow cylindrical slide valve having a controlling bore therethrough, mounted for re-v ciprocatory movement within said inlet passage for controlling the iiow of uid through said opening,` means for moving said slide valve, and a delivery passage leading from said cylinder Vspace.

32. In a fuel pump having a cylinder space and a piston therein, an inlet passage leading to the pump cylinder space, having a controlling canal, and a second passage leading from the pump cylinder space, the combination of an axially adjustable piston-shaped regulating member in said inlet passage for varying the effective crosssection of said controlling canal, said member being directly subjected on one side to fuel pressure in the passage leading from the pump cylinder space, in such a manner that upon an in crease in pressure above a predetermined amount in said second passage, said member is moved to decrease the effective the crossmsection of said inlet passage and lessen the amount of fuel how-m ing to the pump cylinder space.

33. The combination according to claim 32, in which said second passage leading from the pump cylinder space is a return passage which, n

carries back a part of the pumped fuel into the inlet passage so that the regulating member acts under pressure of the fuel in said return passage.

the `action of the return passage pressure upon said member. Y

SAMUEL MEISWINKEL;

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