GB1581977A - Device for dispensing fuel to a combustion engine - Google Patents

Description

(54) DEVICE FOR DISPENSING FUEL TO A COMBUSTION ENGINE (71) We, HOLEC N.V., of No. 93, Stationsplein, Hoog Catharijne (Gode baldkwartier, Kant. van Duvenborch, Nivo 3), Utrecht, the Netherlands, a Body Corporate, organized and existing under the Laws of the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: The invention relates to a device for dispensing fuel to at least one atomizer of a combustion engine, in which a pump chamber arranged in a pump housing and associated with at least one fuel pump has a displacement volume adjustable by control means, communicates through an inlet valve with a fuel supply and through a fuel outlet with the atomizer of the combustion engine and is bounded by at least one displacer body driven so as to reciprocate.

Such a device is known. The displacer body thereof is formed by a cup-shaped piston of a synthetic resin, which does not provide a satisfactory sealing relationship with the cylindrical bore of the pump chamber at a low temperature, since at a low temperature the synthetic resin has strongly shrunk and at a low temperature the synthetic resin is too rigid to be sufficiently deformable under the action of the fuel pressure to get into sealing relationship with the cylindrical bore.

The invention has for its object to provide a satisfactory sealing relationship of the displacer body with respect to the pump chamber, even at a low temperature. For this purpose the displacer body is formed by a plunger which is sealed on its cylindrical outer surface with respect to the cylindrical pump chamber by means of a stationary, elastic sealing ring of a synthetic resin surrounding the cylindrical outer surface of the plunger. In this device the sealing ring surrounding the pump plunger will be drastically shrunk in the cold state so that the sealing relationship with the pump plunger will be satisfactory.

At a high temperature the sealing ring expands slightly more than the plunger, it is true, but in this case the material of the sealing ring has such a flexibility that under the action of the fuel pressure it deforms to an extent such that it will sealingly engage the plunger intimately. This defof- mation is usually ensured by providing the sealing ring with an annular tag engaging the outer surface.

In accordance with the invention there is provided a device for dispensing fuel to at least one atomizer of a combustion engine, in which a pump chamber arranged in a pump housing and associated with at least one fuel pump has a displacement volume adjustable by control-means, communicates, in use, through an inlet valve with a fuel supply and through a fuel outlet with the atomizer of the combustion engine and is bounded by at least one displacer body driven so as to reciprocate, characterised in that the displacer body is formed by a plunger which is sealed on its cylindrical outer surface with respect to the cylindrical pump chamber by means of a stationary, elastic sealing ring of a synthetic resin surrounding the cylindrical outer surface of the plunger.

The above-mentioned and further features of the device embodying the invention will be described more fully hereinafter with reference to a drawing.

In the drawing: Fig. 1 is a plan view partly broken away of a preferred embodiment of a device in accordance with the invention Fig. 2 is a sectional view taken on the line II-II in Fig. 1, Fig. 3 a sectional view taken on the line III-III in Fig. 1, the device being connected with a combustion engine, Fig. 4 shows an electric circuit diagram for the device of Fig. 1, Fig. 5 is an enlarged sectional view of detail V of Fig. 1, Fig. 6 is a diminished, exploded, perspective view of the component parts of Fig. 5, Fig. 7 is an enlarged sectional view taken on the line VII-VII in Fig. 1, Fig. 8 shows on an enlarged scale detail VIII of Fig. 7 in the disengaged state, Fig. 9 shows perspective views of details IX, X and XI of Fig. 7, Fig. 10 is a perspective view of a spraycasting mould for the manufacture of detail XI of Fig. 7, Fig. 11 shows a detail corresponding with Fig. 5 of a further embodiment of a device in accordance with the invention, Fig. 12 shows on an enlarged scale a preferred variant of detail XII of Fig. 7, Figs. 13 and 14 show on an enlarged scale a further detail XIII of Fig. 3, Fig. 15 is a plan view of Fig. 14, and Fig. 16 is a basic diagram for Fig. 14.

The device 1 shown in Figs. 1 to 9 comprises a frame plate 3 of cast or spray-cast aluminium. Two pairs of electro-magnets 2 are firmly connected by bolts 6 between the frame plate 3 and covers 4. Each of the electro-magnets 2 comprises a core 10 of a packet of magnet blades 5 and an energizing coil 14 surrounding said core 10.

Between every pair of alternately energized magnets 2 is arranged a plate-shaped armature 18 so as to be pivotable and slightly displaceable in its direction of length in a bearing 579.

At its free end 15 each armature 18 carries a coupling member 20 with which are connected two displacer bodies 22 of two fuel pumps 32. The stroke of the dsiplacer bodies 22 is determined by adjustable control-means arranged on either side of the coupling members and consisting of two wedges 26 and 33. Each pump 32 comprises a pump chamber 29 provided in a pump housing 42 and having a fuel inlet 27 and a fuel outlet conduit 28, each leading to an atomizer 30 of a combustion engine 31. An inlet valve 39 and an outlet valve 41 are provided in a valve housing 43 to be arranged in the pump housing 42. All valve housings 43 are commonly enclosed in the pump housing 42 by means of an outlet manifold 500 made by spray casting, with which communicates each fuel outlet 501 of each fuel pump 32.

In a bridge piece 401 forming part of two pump housings 42 a nodular cast-iron cylinder 59 is provided for each pump housing 42. The pump housings 42 are pairwise arranged coaxially opposite one another, are rigidly connected by bolts 458 with the frame plate 3 and are provided with connecting nipples 502 forming part of an inlet manifold 503 and passing across the frame plate 3 into the fuel inlets 27, where they are sealed by means of O-rings 504. The inlet manifold 503 is accommodated between the frame plate 3 and a control-cylinder 73 forming part of the control-means, the fastening means of which formed by bolts 505 with toggles 506 secure, in addition, the inlet manifold 503 to the frame plate 3. The inlet manifold 503 has two connecting nipples 507 for the fuel inlet duct 107 communicating with the fuel supply pump 40 and a fuel return duct 108.This return duct 108 communicated through a high-level channel 110 with the fuel inlet 27 of the two valve housings 43. Therefore, the fuel circulates in large quantities through the device 1, the fuel supply pump 40, the ducts 508 and the fuel tank 99 so that the fuel is not excessively heated in the device 1.

The top end 509 of each valve housing 43 extend into a bore 510 of the outlet manifold 500, where it is sealed by means of an O-ring 511, which are brought into a sealing form by tightening the fastening bolts 512 and which get into a non-sealing nominal form as shown in Fig. 8 by loosening said bolts 512, the fuel pumps 32 being thus simultaneously vented.

The outlet manifold 500 is connected on one side with four fuel outlet ducts 28 communicating each with an atomizer 30 by means of a common fastening member 513 through which pass fuel outlet ducts 28 with collars 514 and O-rings 515. The fastening member 513 has a U-shaped profile and hooks by ribs 516 into grooves 517 of the outlet manifold 500.

The displacer bodies 22 are formed by a plunger 518 having a guiding end 519 engaging the pump cylinder 59 and an axially extending sealing portion 520, the cylindrical outer surface of which is in sealing relationship with the cylindrical pump chamber 29 by means of a stationary, annular tag 522 of an elastic sealing ring 521 of a synthetic resin surrounding the cylindrical outer surface of the plunger 518.

The tag 522 extends conically inwardly in the pressing direction of the plunger 518 away from a fastening ring 524 secured to the pump chamber wall 523.

At a low temperature the strongly shrunk sealing ring 521 provides a satisfactory seal and even at a high temperature, owing to the enhanced flexibility of the tag 522, a perfect seal is obtained. The sealing relationship of the plunger 518 with respect to the pump chamber 59 is particularly maintained because the free guiding end of the plunger 518 is held in a cylindrical supporting face of the pump chamber 29 and the sealing ring 521 engages the sealing portion 520 located between the two ends of the plunger 518. The plunger 518 is preferably formed by a hard-steel plunger body 525 surrounded by a cylindrically ground guiding sleeve 526, which is fastened thereto.

The device 1 comprises two coupling members 20 and the displacer bodies 22 of each pair of fuel pumps 32 are coupled with one another by means of a coupling member 20. Each coupling member 20 is connected by means of an elastic coupling 66 with an armature 18. The displacement volume of each fuel pump 32 is determined by the stroke of the coupling member 20, which reciprocates by a spherical arm 79 between the wedges 26 and 33.

Two housing blocks 69 consist each of two joined pump housings 42, between which are disposed wedges 26 and 33, which serve as common control-means for each of the pumps 32. A satisfactory seal of the plungers 518 is maintained since the guiding ends 519 of the plungers 518 moving in the cylinders 50 absorb the tilting forces produced when the arm 79 strikes a wedge 26 or 33 beyond the axis 85 of the cylinder 59.

In order to accurately align the cylinder bores of the pairwise coaxially opposite pumps 32 hard steel cylinders 59 are arranged in coaxial, short bores 400 of a U-shaped bridge piece 401.

The manufacture and mounting are carried out as follows.

First a long, continuous bore is bored and reamed in a metal body. Then a recess 404 is milled to form a U-shaped bridge piece 401 with two separate, accurately aligned, short bores 400. The bore 410 of the coupling piece 20 is separately reamed and subsequently with the interposition of an elastic coupling 66 the coupling member 20 is fastened by means of a pin 424 to an armature 18. In order to facilitate mounting each bore 400 is provided with a slot 527 having a width b1 exceeding the diameter b2 of the plunger 518. Then the coupling member 20 with the plungers 518 fastened thereto is passed through the slots 527 into the bridge piece 401. Then the cylinders 59 are inserted with a narrow fit into the bores 400 and passed around the guiding ends 519 of the plungers 518 previously coated with adhesive sold under the Registered Trade Mark "Araldite".The guiding ends 519 are then engaged with sliding fit in the cylinders 59 so that the coupling member 20 is accurately aligned. Only then the bridge piece 401 is glued by glue 438, for example, Araldite, to the pump housings 42, which are secured by means of bolts to the frame plate 3. Since owing to the use of the bridge piece 401 the relative dispositions of the pump housings 42 are not of importance, the pump housings 42 can be simply fastened to the frame plate 3 and may be made at low cost for example from spray-cast aluminium Or synthetic resin.

The pump chamber 29 comprises a pump compartment 532 protected from dirt by a filter 531 and accommodating the plunger 51S and a valve compartment 534 communicating with the former and protected from dirt by a further filter 533 and limited by the inlet valve 39 and the outlet valve 41 in the valve housing 43 so that the sensitive parts of the pump 32 are protected.

Each pump cylinder 59 is sealed by means of an O-ring 535 with respect to the pump housing 42.

The wedge 26 is driven by a heavy piston 80 of a control-cylinder 73 communicating downstream of an air inlet valve 113 with the air inlet manifold 72 of the combustion engine 31. Outside the control-cylinder 73, at the end remote from the wedge 26, a switch 82 is adjustable in an axial direction and actuated by a hat-like cup spring 166 of the piston 80. The switch 82 cuts off the pumps 32 at a drop below a given pressure in the inlet manifold 72. The reset spring 167 bears through the hat-like cup spring 166 and a ball 168 contained therein on the piston 80. The air chamber 528 of the control-cylinder 73 communicates through a conduit 529 with the filter 530 of the air inlet manifold 72.The controlmeans for adjusting the displacement volume of the pump chambers 29 comprise, apart from the wedge 26, with the control-cylinder 73, a wedge 33 having a control-pressure chamber 536 communicating with the inlet manifold 72 of the combustion engine 31 through an opened valve 537, which is only opened upon a release of the gas pedal 538 controlling the combustion engine 31 in order to reduce the quantity of fuel pumped round by the fuel pumps 32. When the gas pedal 538 is actuated, a cable 560 draws the valve member 561 against the action of the spring 562 down into a closing position so that leakage air can fill out the control-pressure chamber 536. The control-pressure chamber 536 is bounded by a diaphragm 539, which is urged upwards by a spring 540 and which is connected with a sleeve 541.The wedge 33 bears via a collar 542 of a two- position mechanism 543 on the lower edge 544 of the sleeve 541. The wedge 33 is arranged around a rod 545 with a shoulder 546. A spring 547, supported from the shoulder 546, urges the wedge 33 downwards against a nut 548. The shoulder 546 is axially displaceable in the collar 542, whilst a ball 549 moves in an external, cardiform groove 550 of the shoulder 546 and in an internal annular groove 551 of the collar 542. This two-positioa.mecha- nism 543 is adjusted by means of a manually operated control-knob 553 through a cable 552, which engages the top end n the rod 545. By means of the-knob 553 the level correction is performed in order to reduce the quantity of fuel only at a very high level. Fig. 3 indicates the level-corrected position.In the normal, non-operative position the ball 549 is located beneath a cardiform groove 550. The controlmeans of the wedge 33 are accommodated in the outlet manifold 500.

The shapes of the outlet manifold 500 and of the inlet manifold 503 are shown in detail in Fig. 9. The inlet manifold 503 has a recess 570 on the top side, which communicates with a nipple 571, which is connected through a conduit 572 with the inlet manifold 72 downstream of the choke valve 113. From the recess 570 the vacuum condition of the inlet manifold 72 is transferred through the aperture 574 and the filter 573 to above the piston 80 of the cylinder 73.

Fig. 10 illustrates that the inlet manifold 503 can be readily manufactured by means of a mould 580 by a spray-casting process. The mould 580 comprises an upper mould 581 and a lower mould 583 and two cores 582. In a similar manner the outlet manifold 500 can be manufactured.

Each electrrrmagnet 2 is energized by means of a circuitry shown in Fig. 4. An input K: receives a control-pulse from the pulse producer 34, which is coupled with a cam shaft 163 of the engine 31. The pulse producer 34 has a rotating contact 155, which comes alternately into contact with one of the four contacts 16 for energizing the electromagnets 2 in order of succession. Each of said four contacts 16 is connected to an input terminal K3 of one of four circuits 170. In this way an atomizer 30 injects the fuel required for each cylinder during each cycle of the combustion engine 31 at the correct instant.The order of succession of energization of the electromagnets 2 is chosen so that during each cycle each of the wedges 26 and 33 is instantaneously released from a coupling member 20 so that they can each be displaced with a slight force. Between the accumulator 35 and the contact 155 is arranged the switch 82 so that, when the switch 82 is switched off, no control-pulses are produced.

The device shown in Fig. 11 is distinguished as follows from that of Fig. 5. The sealing ring 554 has a U-shaped profile of elastic material, for example, rubber and preferably a synthetic resin, whilst inside a metal circlip 55s is arranged, which urges the two tags 556 away from one another in order to bring them into sealing relationship with a ring 557, in which the sealing ring 554 is arranged. The sealing ring 554 bears in an axial direction on a collar 558 of the ring 557, which is accommodated with pressing fit in the bridge piece 401. A nodular cast-iron ring 559 is arranged with pressing fit, in which ring is guided the sealing end 520 of the plunger 518.

As shown in Fig. 12 the fuel outlet duct 28 formed by a hose enveloped in a metal tissue 563, is slipped onto the grooved end 565 of a nipple 564, which is subseqently enclosed with its collar 566 in an annular chamber 567 of the outlet manifold 500, it being sealed by means of an O-ring 568.

The fuel outlet duct 28 is narrowly enclosed in a bore 569 of the fastening member 513 so that the elastic material pressed into the grooves 575 of the nipple 564 cannot get out of them.

The variant XIII shown in Fig. 13 for the adjustment of the wedge 33 of Fig. 3 comprises a control-pressure chamber 536 which communicates with the inlet manifold 72, but which is better sealed than in Fig. 3 against the open air, since the diaphragm 539 is held in a fairly long sleeve 577, which is arranged with an axial, fairly long, narrow sliding fit in a stationary ring 584 and is protected from penetrating dirt by a felt ring 585. The adjustment of the fuel displacement during idling is performed by turning the control-knob 586, as a result of which a sleeve 587 engaging internal screwthread 588 of the sleeve 577 together with the wedge 33 is axially displaced. The sleeve 587 comprises again a two-position mechanism 543 of the abovementioned kind.

The variant of Fig. 14 is distinguished from that of Fig. 13 by a different setting mechanism for the wedge 33 with respect to the diaphragm 536. The sleeves 577 and 587 of Fig. 13 are united in Fig. 14 to a single, long sleeve 589. The wedge 33 bears on a nut 590, which is guarded against turning and accommodated in an elongated slot 591 in a supporting member 592, in which the wedge 33 bears on a housing block 69. By turning the rod passed through the wedge 33 the nut 590 and hence the wedge bearing on the same are displaced in an axial direction. The rod 545 bears through a bearing ring 593 on a table 594, which is rigidly secured to the sleeve 589. The spring 547 urges the wedge 33 against the nut 590. The table 594 holds a small electric motor 595, which drives via a worm 596 a worm wheel 597 rigidly secured to the rod 545 for setting the wedge 33. The starting position can be varied by drawing upwards the rod 545 by means of a pull-knob 598 against the spring 547 in order to discouple the worm 596 and the worm wheel 597 by subsequently turning the rod 545 and dropping it in a different position. The chamber 536 communicates with a low pressure in the inlet manifold 72 through a closing member 576, which is closed in normal operation but which is opened at a low number of revolutions, i.e. during idling.

For this purpose a rate counter 579 counts the pulses of the interruptor 599 with the coil 459 driven by the combustion engine 31. When the rate is lower than the value adjusted in a comparator 460, the valve 578 is moved into the open state so that the pressure in the chamber 536 is drastically reduced and the wedge 33 is urged downwards to reduce the fuel displacement.

The basic diagram of Fig. 16 shows the control of the motor 595, which can be energized through a bridge circuit of four transistors 600 and two comparators 601 for actuation in both directions. To the two comparators 601 are applied as input signals the real value signal and the desired value signal respectively derived from a real value potentiometer 602 and a desired value potentiometer 603. The real value potentiometer 602 is driven by the electric motor 595 and is coupled with the drive of the wedge 33, since a pinion 606 fastened to the rod 545 drives a larger pinion 607 having a pin 608. This pin 608 engages a cam wheel 609, which is arranged on the shaft 610 of the potentiometer 602.The desired value potentiometer 603 is set by an electric motor 611, which is controlled through an amplifier 612 and a combination network 613 by measuring members 614 consisting, for example, a thermometer measuring the combustion engine temperature, a barometer, a COmeter for assessing the CO percentage .in the exhaust gases of the combustion engine and/or a measuring member for other parameters.

WHAT WE CLAIM IS: - 1. A device for dispensing fuel to at least one atomizer of a combustion engine, in which a pump chamber arranged in a pump housing and associated with at least one fuel pump has a displacement volume adjustable by control-means, communicates, in use through an inlet valve with a fuel supply and through a fuel outlet with the atomizer of the combustion engine and is bounded by at least one displacer body driven so as to reciprocate, characterized in that the displacer body is formed by a plunger which is sealed on its cylindrical outer surface with respect to the cylindrical pump chamber by means of a stationary, elastic sealing ring of a synthetic resin surrounding the cylindrical outer surface of the plunger.

2. A device as claimed in claim 1, characterized in that the sealing ring comprises a ring of elastic material having a U-shaped profile, in which a metal circlip is arranged.

3. A device as claimed in claim 1 or 2, characterized in that the sealing ring has an annular tag engaging the outer surface.

4. A device as claimed in claim 3, characterized in that said tag extends inwardly in the pressing direction of the plunger away from fastening ring secured to the pump chamber wall.

5. A device as claimed in any one of the preceding claims, characterized in that the free end of the plunger is supported in a cylindrical supporting surface of the pump chamber and the sealing ring is in engagement with the plunger portion located between its two ends.

6. A device as claimed in any one of the preceding claims, characterized in that the plunger consists of a hard-steel plunger body and a cylindrical guiding sleeve surrounding said body and fastened thereto.

7. A device as claimed in any one of the preceding claims characterized in that the pump chamber comprises a pump compartment accommodating the displacer body and being protected from dirt by a filter and valve compartment communicating with the pump compartment, protected from dirt by a further filter and arranged in a valve housing bounded by the inlet valve and an outlet valve.

8. A device as claimed in any one of the preceding claims wherein the pump chambers of at least two fuel pumps are arranged coaxially at a distance from one another, are adapted each to communicate through an inlet valve with a fuel supply and through a fuel outlet with an atomizer of the combustion engine and are bounded by a displacer body reciprocatorily driven by driving means, which are coupled with one another with the aid of a coupling member arranged between the ,two fuel pumps, the pump chambers being bounded by pump sleeves arranged in coaxial bores in the two ends of a bridge piece, one end of which is located in -the pump housing of one fuel pump and the other end of which is located in the pump housing of the other fuel pump, whilst at least one intermediate piece interconnects the two ends of the bridge piece, and wherein the coaxial bores have an axial slot for allowing the displacer bodies to pass in a radial sense during assembly.

9. A device as claimed in claim 8, characterized in that each pump cylinder is sealed by an O-ring with respect to the pump housing.

10. A device as claimed in any of the preceding claims in which each of a plurality of pump chambers arranged in a pump housing and each associated with a respective one of a plurality of fuel pumps has a displacement volume adjustable by control-means, communicates, in use, through an inlet valve with a fuel supply and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (23)

**WARNING** start of CLMS field may overlap end of DESC **. operation but which is opened at a low number of revolutions, i.e. during idling. For this purpose a rate counter 579 counts the pulses of the interruptor 599 with the coil 459 driven by the combustion engine 31. When the rate is lower than the value adjusted in a comparator 460, the valve 578 is moved into the open state so that the pressure in the chamber 536 is drastically reduced and the wedge 33 is urged downwards to reduce the fuel displacement. The basic diagram of Fig. 16 shows the control of the motor 595, which can be energized through a bridge circuit of four transistors 600 and two comparators 601 for actuation in both directions. To the two comparators 601 are applied as input signals the real value signal and the desired value signal respectively derived from a real value potentiometer 602 and a desired value potentiometer 603. The real value potentiometer 602 is driven by the electric motor 595 and is coupled with the drive of the wedge 33, since a pinion 606 fastened to the rod 545 drives a larger pinion 607 having a pin 608. This pin 608 engages a cam wheel 609, which is arranged on the shaft 610 of the potentiometer 602.The desired value potentiometer 603 is set by an electric motor 611, which is controlled through an amplifier 612 and a combination network 613 by measuring members 614 consisting, for example, a thermometer measuring the combustion engine temperature, a barometer, a COmeter for assessing the CO percentage .in the exhaust gases of the combustion engine and/or a measuring member for other parameters. WHAT WE CLAIM IS: -

1. A device for dispensing fuel to at least one atomizer of a combustion engine, in which a pump chamber arranged in a pump housing and associated with at least one fuel pump has a displacement volume adjustable by control-means, communicates, in use through an inlet valve with a fuel supply and through a fuel outlet with the atomizer of the combustion engine and is bounded by at least one displacer body driven so as to reciprocate, characterized in that the displacer body is formed by a plunger which is sealed on its cylindrical outer surface with respect to the cylindrical pump chamber by means of a stationary, elastic sealing ring of a synthetic resin surrounding the cylindrical outer surface of the plunger.

2. A device as claimed in claim 1, characterized in that the sealing ring comprises a ring of elastic material having a U-shaped profile, in which a metal circlip is arranged.

3. A device as claimed in claim 1 or 2, characterized in that the sealing ring has an annular tag engaging the outer surface.

4. A device as claimed in claim 3, characterized in that said tag extends inwardly in the pressing direction of the plunger away from fastening ring secured to the pump chamber wall.

5. A device as claimed in any one of the preceding claims, characterized in that the free end of the plunger is supported in a cylindrical supporting surface of the pump chamber and the sealing ring is in engagement with the plunger portion located between its two ends.

6. A device as claimed in any one of the preceding claims, characterized in that the plunger consists of a hard-steel plunger body and a cylindrical guiding sleeve surrounding said body and fastened thereto.

7. A device as claimed in any one of the preceding claims characterized in that the pump chamber comprises a pump compartment accommodating the displacer body and being protected from dirt by a filter and valve compartment communicating with the pump compartment, protected from dirt by a further filter and arranged in a valve housing bounded by the inlet valve and an outlet valve.

8. A device as claimed in any one of the preceding claims wherein the pump chambers of at least two fuel pumps are arranged coaxially at a distance from one another, are adapted each to communicate through an inlet valve with a fuel supply and through a fuel outlet with an atomizer of the combustion engine and are bounded by a displacer body reciprocatorily driven by driving means, which are coupled with one another with the aid of a coupling member arranged between the ,two fuel pumps, the pump chambers being bounded by pump sleeves arranged in coaxial bores in the two ends of a bridge piece, one end of which is located in -the pump housing of one fuel pump and the other end of which is located in the pump housing of the other fuel pump, whilst at least one intermediate piece interconnects the two ends of the bridge piece, and wherein the coaxial bores have an axial slot for allowing the displacer bodies to pass in a radial sense during assembly.

9. A device as claimed in claim 8, characterized in that each pump cylinder is sealed by an O-ring with respect to the pump housing.

10. A device as claimed in any of the preceding claims in which each of a plurality of pump chambers arranged in a pump housing and each associated with a respective one of a plurality of fuel pumps has a displacement volume adjustable by control-means, communicates, in use, through an inlet valve with a fuel supply and

through a fuel outlet with a respective one of a plurality of atomizers of the combustion engine and is bounded by at least one displacer body reciprocatorily driven by driving means, characterized in that the fuel inlet of each fuel pump communicates with a supply member made by spray-casting and joining the pump housing of each fuel pump.

11. A device as claimed in claim 10, characterized in that the supply manifold has for each fuel pump a nipple extending across a mounting plate and being sealed by means of an O-ring with respect to the pump housing.

12. A device as claimed in claim 10 or ]1, characterized in that the supply manifold is arranged between a frame plate and a control-cylinder forming part of the control-means and in that the fastening means for the control-cylinder serve, in addition, to secure the supply manifold to the frame plate.

13. A device as claimed in any one of the preceding claims in which each of a plurality of pump chambers arranged in a pump housing and each associated with a respective one of a plurality of fuel pumps has a displacement volume adjustable by control-means, communicates, in use, through an inlet valve with a fuel supply and through a fuel outlet respective one of a plurality of atomizers of the combustion engine and is bounded by at least one displacer body reciprocatorily driven by driving means, characterized in that the fuel outlet of each fuel pump communicates with an outlet manifold made by spray casting.

14. A device as claimed in claim 13, characterized in that the outlet manifold is connected on one and the same side with a plurality of fuel outlet ducts communicating with atomizers by means of a common fastening member through which passes ducts provided with collars and O-rings.

15. A device as claimed in claim 14, characterized in that the fastening member has a U-shaped profile.

16. A device as claimed in claim 13, 14 or 15, characterized in that the outlet manifold, by means of sealing members, seals the top ends of the fuel pumps against leakage and in that by loosening screws fastening the outlet manifold to the fuel pumps the fuel pumps can be vented.

17. A device as claimed in claim 16, characterized in that each fuel pump is provided with a valve housing accommodating an inlet valve and an outlet valve, a top end of which extends into the outlet manifold and is surrounded by an O-ring.

18. A device as claimed in any one of the preceding claims characterized in that the control-means comprise at least one control-pressure chamber communicating, in use, with the inlet manifold of the combustion engine through an opened valve, which is only opened at a release of the gas pedal controlling the combustion engine in order to reduce the quantity of fuel pumped up by the pump.

19. A device as claimed in any one of the preceding claims characterized in that the control-means comprise at least one level-correction member which is remotely adjustable between a non-operative position and a correction position to be adjusted only at a high level for reducing the fuel displacement of the pump.

20. A device as claimed in any one of the preceding claims characterized in that the control-means comprise a controlled electric motor.

21. A device as claimed in claim 20, characterized in that the control-means comprise a reduction driving gear actuated by the electric motor.

22. A device as claimed in claim 20 or 21, characterized in that the control-means comprise a desired value potentiometer and a real value potentiometer driven by the electric motor and coupled with a controlmember (for example, a wedge).

23. A device for dispensing fuel to a combustion engine, substantially as hereinbefore described with reference to the accompanying drawings.