DE10129308C1 - Fuel feed device for 2-stroke diesel engine used for e.g., for a ships drive, has at least one valve closure of fuel injection valves for each engine cylinder de-activated at partial load by associated control piston - Google Patents

Abstract

The fuel feed device has several fuel injection valves for each engine cylinder, each having at least one flow channel (18) leading to a jet bore, passing through a spring-loaded valve closure (35), raised from its valve seat (38) when a given fuel pressure is reached. At least one valve closure is pressed against the valve seat via an associated control piston (46), providing a force which is greater than the fuel pressure force at the normal opening pressure and less than the fuel pressure force at the maximum permissible fuel pressure.

Description

The invention relates to a device for supplying fuel to Internal combustion engines, especially two-stroke large diesel engines, with the Cylinder-associated injection valves, preferably with each several injectors per cylinder, the injectors each at least one leading to a nozzle bore arrangement, to one pressure line to which fuel can be applied by means of a pressure source connectable flow channel having at least one under the action of a spring pressed against a seat and by the Fuel on reaching a predetermined pressure from the assigned one Seat removable locking body interspersed.

A device of this type is known from EP 0744 007 B1 by the applicant known. In this known arrangement, passivation is individual Injectors not possible. Therefore, even at partial load, they are all Injectors activated. This leads to one with smaller loads comparatively low injection pressure and accordingly to one poor atomization and combustion of the fuel. The consequence of which are not only an unstable run, but also undesirable Deposits of combustion residues that lead to an increased Can cause wear. Arrangements of the known type have been found therefore not reliable enough.  

DE 36 01 462 A1 also shows a fuel injection device, two in the fuel line to the injector separate, each via an electro-hydraulic control element controlled needle valves are arranged. This requires a complex Construction with a large space requirement. Also the injector cannot be switched off.

Proceeding from this, it is therefore the object of the present invention a device of the type mentioned with simple and to improve cost-effective means so that at least part of the existing injection valves optionally at least for a short time is passivable.

This object is achieved in that at least one Closing body penetrated by the flow channel of at least one part of the existing injection valves by means of an associated one Control piston can be pressed against the respectively assigned seat, the force exerted by the control piston on the closing body to hold the Injectors in permanent closed position larger than that of Fuel pressure exerted on the closing body during part-load operation and less than one from the maximum allowable fuel pressure on the Closing body is exerted force.

Here it is advantageously possible to apply pressure of the control piston to the closing body in contact with the assigned seat hold and thus block a flow in the flow channel, so that there is no injection. It is therefore advantageous possible to passivate part of the injection valves at partial load, so that a comparatively high one on the remaining injection valves Injection pressure and thus a good atomization of the fuel is achieved becomes what leads to good combustion and suppression of leads to undesirable deposits. Under partial load operation is the with to understand the load range beginning with the no-load load.  

With the invention Measures can therefore be taken to the disadvantages of completely avoid known arrangements. By the fact that from Control piston force exerted on the associated closing body smaller than one of the maximum permissible fuel pressure on the closing body exerted force, it is also ensured that a mechanical Breakage of a component as a result of an impermissible increase in pressure in the Fuel system is avoided, which is beneficial to the Operational safety affects. If the control piston is not included The pressure medium is acted upon, the inventive works Injection valve like a conventional injection valve. This is  ensures that even if the control piston fails assigned exposure device no risk of explosion consists. The measures according to the invention thus ensure high reliability and security. Another advantage is there too see that the device according to the invention can also be used for this can vary the opening pressure of the closing body. The Measures according to the invention therefore also offer a high level Versatility.

Advantageous refinements and practical training of overriding measures are specified in the subclaims. So can the control piston advantageously by means of a hydraulic Pressure medium can be acted upon, the application being expedient by means of a load-dependent controllable by a control device Valve can be switched on and off. These measures result in a very simple design and high functional reliability. Surrender at the same time very short dead times in an advantageous manner. With diesel engines can Diesel oil should be used as a hydraulic pressure medium. This ensures that in the event of a leak Hydraulic fluid mixing with the fuel is harmless is.

Another advantageous measure can be that at least a group of control pistons a common, to a pressure source connected, with a preferably adjustable safety valve provided supply loop is assigned, from the to the associated spool leading branch lines in which In each case a valve controllable by means of the control device is provided is. These measures result in a particularly simple and cost-effective training of one assigned to all control pistons Pressure medium supply device with a pressure source and a safety valve to limit the pressure, so that there is also a particularly space-saving arrangement.  

The spring associated with the closing body can advantageously be on Control piston be supported. By pressurizing the The control piston changes the spring force. It is therefore up here easily possible with the help of the measures according to the invention not only the closing body completely in its closed position hold. Rather, the spring preload can be easily and thus the opening pressure of the closing body can be varied. there it is expedient to the output side, the Nozzle bore arrangement adjacent closing body.

The first, arranged in the entrance area of the injection valve Control piston assigned to the closing body can advantageously be provided by one of a shoulder of a stationary bearing protruding from Flow channel penetrated through the guide pin, the with an axial degree of freedom of movement in the closing body he intervenes. These measures result in reliable axial guidance of the closing body and the associated control piston. simultaneously This results in a very compact closing body control piston Arrangement that instead of a closing body of the known Arrangements can be used, which is a simple retrofit of the known arrangements.

Another advantageous measure can be that the Guide pin with a radial one that is open when the control piston is unloaded Circulation hole is provided with a return line communicated. The circulation hole allows ventilation of the Fuel system and a fuel circulation when switched off but the internal combustion engine is on standby, which is particularly the case with the use of heated fuel, especially heavy oil, for Avoid thermal shock and / or line clogging is an advantage.  

The control device can advantageously be designed such that when Partial load the control pistons of the injectors provided for each cylinder in a predetermined cycle alternately pressurized. This ensures that the cylinders each at partial load assigned injectors are alternately activated or passivated can. Through this alternating change between activation and Passivation is a cooling of the individual Injectors and thus a shock effect at the Re-commissioning counteracted. The same applies to coking the nozzle bores. The measures mentioned therefore lead to a Increase in operational security.

Further advantageous refinements and practical training of overriding measures are in the remaining subclaims specified and from the example description below using the Drawing can be removed more closely.

In the drawing described below:

Fig. 1 is a schematic representation of an internal combustion engine with an associated fuel supply system or

Fig. 2 is a longitudinal section through a first embodiment of an injector according to the invention,

Fig. 3 is an enlarged view of the control valve arrangement of the injector according to Fig. 2,

Fig. 4 is a schematic representation of one of the control valve assembly of all the injectors associated Druckmittelversorgungs- and control device,

Fig. 5 is a horizontal section through the connecting flange of the injection valve according to FIG. 2.

Fig. 6 is a longitudinal section through a second embodiment of an injection valve according to the invention and

Fig. 7 shows a variant for the arrangement of FIG. 4.

The indicated in Fig. 1 internal combustion engine 1, which is the two-stroke large diesel engine may be, for example a find use as a ship's drive, includes a plurality of cylinders 2, of which in Fig. 1 only one is shown. Each cylinder 2 is provided with two injection nozzles 3 , each of which is assigned a common injection pump 4 . The injection pumps 4 of all the cylinders 2 are assigned a common supply loop, which has a forward load 5 a and a return load 5 b and is provided with a tank 6 , a supply pump 7 and a pressure control valve 8 . In the pressure regulating valve 8 arranged upstream Vorlaufast 5 a of the supply loop 5 a pressure of 8 bar is provided in the example shown, in the pressure-regulating valve 8 downstream return branch 5b, a pressure of 4 bar. The fuel pumps 4 are connected on the suction side to the forward load 5 a and on the return side to the return load 5 b of the supply loop mentioned. The injection valves 3 are connected on the input side via pressure lines 9 to the fuel outputs of the associated fuel pump 4 and on the return side via return lines 10 to the return branch 5 b of the supply loop 5 .

The injection valves 3 can be fixed on the cylinder head of the respectively assigned cylinder 2 . For this purpose, as best seen in FIG. 2, the injection valves 3 are provided with a flange 11 at the upper end. On the one hand, this is provided with a threaded pin 12 for connecting the associated pressure line 9 . On the opposite side, the flange 11 is provided with a threaded collar 13 , to which an outer nozzle tube 15 can be fixed by means of a union nut 14 , which carries a downwardly projecting nozzle body 16 , which is provided with injection bores 17 , which as a whole have 18 designated flow channel with the connectable to the threaded pin 12 pressure line 9 in terms of flow.

The parts which follow one another in the flow direction, from the threaded pin 12 to the nozzle body 16, are provided with suitable recesses for forming the flow channel 18 .

Accordingly, the flow channel 18 passes through the flange 11 together with the threaded pin 12 , then a control valve arrangement arranged inside the casing tube 15 , designated as a whole by 19, then an intermediate piece 20 , then a closing device arranged in front of the nozzle body 16 , designated as a whole by 21, and then opens into a central bore of the nozzle body 16 , from which the injection bores 17 extend.

In the example on which FIG. 2 is based, the intermediate piece 20 is provided with a fixed upper spring plate and a movable lower spring plate 22 , 23 for a valve spring 24 which is assigned to the locking device 21 and is designed as a coil spring. The closing device 21 contains a closing body 25 which is supported on the movable spring plate 23 provided with a support shoulder for this purpose and which is guided in a central bore of a seat part 26 accommodated in the casing tube 15 , to which the nozzle body 16 connects. The closing body 25 has a front pin 27 which is tapered with respect to its guide surfaces and which is provided with a conical sealing surface which can be brought into contact with an associated seat surface 28 of the seat part 26 . The pin 27 carries a front grooved in the axial direction of the projection, which engages through the fitting on the nozzle body 16 portion of the seat member 26 and projects into the central bore of the nozzle body sixteenth The seat part 26 is on the one hand supported on the nozzle body 16 and the other hand to a subsequent to the intermediate piece 20 extension piece 29, provided with an axial degree of freedom of a to the flow channel 18 associated, axial blind bore 30 of the closing member 25 engaging pin with one and the above-mentioned bearing base part comprises is.

Due to its smaller diameter, the pin 27 of the closing body 25 which can be brought into engagement with the seat surface 28 is surrounded by an annular space 31 which is connected to the central blind hole 30 by oblique bores 32 . As soon as fuel with sufficient pressure is present in the annular space 31 , the closing body 25 is thereby raised against the action of the valve spring 24 , as a result of which its sealing surface is lifted from the associated seat surface 28 and the flow path from the annular space 31 to the injection bores 17 is released, so that an injection he follows.

The control valve arrangement 19 is constructed similarly to the closing device 21 described above. The control valve arrangement 19 , as can best be seen from FIG. 3, also contains a closing body 35 , which is guided in a central bore of an associated seat part 36 and has a front pin 37 , which contains a circumferential, conical sealing surface which engages an associated seat surface 38 surrounding a lower outlet bore of the seat part 36 can be brought. The seat part 36 , as can be seen from FIG. 2, is supported with its lower end on the intermediate piece 20 and lies with the upper end of a rear collar 40 on a bearing piece 39 which, as FIG. 2 further shows, in an associated recess of the flange 11 is used. The bearing piece 39 is provided with a downwardly projecting guide pin 41 which, with an axial degree of freedom of displacement, engages in a central blind bore 42 of the closing body 35 which belongs to the flow channel 18 and on which the lower end of a spring 45 designed as a compression spring is supported. The blind bore 42 is connected by oblique bores 43 to an annular space 44 surrounding the pin 37 . Here too, the closing body 35 can therefore be raised by the fuel under pressure in the annular space 44 against the action of the spring 45 assigned to the closing body 35 .

The spring 45 is supported on the one hand on the closing body 35 and on the other hand on a control piston 46 associated therewith, which is penetrated by the pin 41 of the bearing piece 39 and is surrounded by the collar 40 of the seat part 36 , so that there is an exact guidance. The spring 45 is weaker than the valve spring 24 , so that the seat part 35 is lifted off the associated seat 38 even at a lower fuel pressure and the fuel is therefore present in the area of the locking arrangement 21 .

In the closed position on which FIG. 3 is based, the sealing body 35 is supported with its sealing surface on the associated seating surface 38 of the seat part 36 and the control piston 46 with a rear piston surface on an opposite shoulder surface of the bearing piece 39 which comprises the pin 41 . The sealing body 35 and the control piston 46 are spaced apart from one another, so that a gap 47 results in the region of the opposite end faces. The pin 41 of the bearing piece 39 is provided in the area of this gap 47 with a radial bore 48 which has a comparatively small diameter and extends from the central bore of the bearing piece 39 belonging to the flow channel 18 . The radial bore 48 opens into the gap 47 and associated therewith into which the spring 45 through peripheral recesses of the closing body 35 and the control piston 46 of the annular chamber region encompassed by the collar 40 formed hole 49 of the seat part 36th The bore 49 is connected via cross bores 50 to the interior 51 of the casing tube 15 , which is connected to the associated return line 10 via a bore system 52 indicated in FIG. 2. The radial bore 48 thus communicates with the associated return line. The circulation bore 48 enables fuel circulation when the control piston 46 is raised, ie when the control piston 46 is in the position shown in FIG. 3. This enables the fuel system to be vented and prevents undesired cooling during stand-by operation.

With the aid of the control piston 46 , the associated closing body 35 can be pressed against the seat 38 against the action of the fuel present in the annular space 44 and can accordingly be held in the closed position. In this way it is possible to passivate the relevant injection valve 3 .

For this purpose, the control piston 46 can be acted upon with a pressure medium in the region of its rear piston surface facing away from the associated closing body 35 . This results in a working space delimited by this piston surface, the opposite shoulder surface of the bearing part 39 and the pin 41 of the bearing part 39 and the collar 40 of the seat part 36 . A hydraulic pressure medium which is less compressible than pneumatic pressure mediums is expediently used as the pressure medium. In diesel engines, diesel oil can expediently be used as the pressure medium, so that any leakage liquid which may escape from the work space mentioned can be absorbed by the circulating fuel without problems.

The pressure medium is provided by a provision device on which FIG. 4 is based. This contains a supply loop 54 a and a return flow 54 b comprehensive supply loop, which a tank 55 and a supply pump 56 and an adjustable pressure valve 57 are assigned. One of the number of stub lines 58 , here two stub lines 58 , provided from the number of injection valves 3 per cylinder 2 , each lead to the pressure medium inlet of one injection valve 3 of each cylinder 2 from the supply loop mentioned. For this purpose, the branch lines 58 are branched into a number of branch lines corresponding to the number of cylinders, as indicated by broken lines in FIG. 4. A controllable shut-off valve 59 is arranged in the stub lines 58 upstream of the branch. This can be an electromagnetic slide valve. The shut-off valves 59 can be controlled by means of a control device 60 containing a computer, as indicated by signal lines 61 .

The pressure which can be generated by means of the pump 56 is so high that the control piston 46 acted upon by this exerts a force on the associated closing body 35 which is greater than the force exerted by the spring 45 on the closing body 35 during normal injection operation, that is to say greater than that of Fuel force exerted on the closing body 35 at normal opening pressure. The upper limit of the force exerted on the closing body 35 is predetermined by the pressure valve 57 . This is set so that there can be no mechanical breakage of a component due to excessive fuel pressure, i.e. before the weakest component mechanically breaks, the closing body 35 is lifted off the associated seat 38 and thus the fuel system upstream from the seat 38 is relieved ,

When the control piston 46 holds the closing body 35 under load, the circulation bore 48 is covered by the control piston 46 , so that no fuel circulation takes place. This ensures that a desired, high injection pressure is achieved at the working injection valves.

By suitably pressurizing the control pistons 46 of the injection valves 3 , these can optionally be passivated. It is therefore possible to passivate one of the two injection valves 3 of each cylinder 2 at a low load acting on the engine 1 , which leads to what enables an exact metering of the fuel even with a comparatively low fuel requirement and a high injection pressure and thus a good one Atomization of the fuel and, as a result, good combustion is guaranteed. The computer 59 of the control device 60 therefore controls the valves 59 in such a way that only one injection valve 3 is activated below a certain partial load per cylinder 2 and the rest of the injection valve 3 is passivated. The computer of the control device 60 is accordingly provided with a suitable input 62 for signals assigned to the load. In order to obtain the most uniform possible thermal load on all the injection valves 2 and to avoid coking of the injection bores 17 even in the case of a partial load operation of the aforementioned type, the injection valves 3 of each cylinder 2 are alternately activated or passivated every two minutes. For this purpose, the program stored in the computer of the control device 60 is equipped accordingly.

As can be seen from FIG. 4, the pressure medium required for actuating the control pistons 46 is supplied via the flanges 11 of the injection valves 3 . For this purpose, the flanges 11 , as can be seen from FIG. 5, are provided with radial bores 63 , to which the branch lines 58 can be connected. In the example shown, two pair of radial bores 63 are provided, one of which can be plugged. This double arrangement of the radial bores 63 facilitates the line routing. The radial bores 63 open into a circumferential groove 64 in the region of the bore of the flange 11 assigned to the bearing body 39 . The groove 64 communicates, as can be seen in FIGS . 2 and 3, with a bore system 65 on the bearing part side leading to the work chamber assigned to the control piston 46 . The flanges 11 are also provided with a connection bore 66 assigned to the return line 10 , which communicates with the above-mentioned bore system 52 for the fuel return on the bearing part side.

In the exemplary embodiment described above, a control piston 46 is assigned to the respective upper closing body 35 of the injection valves 3 . However, it would also be conceivable, in addition or as an alternative, to also assign a suitable control piston to the lower closing body 25 for optionally holding this closing body 25 against the effect of the fuel pressure, as can be seen from FIG. 6. The basic structure of the arrangement according to FIG. 6 corresponds to the structure of the example on which FIG. 2 is based. Therefore, only the differences are described below, the same reference numerals as above being used for corresponding parts.

In the embodiment according to FIG. 6, the closing body 25 of the closing device 21 arranged upstream of the nozzle body 16 is assigned a control piston 70 . In this arrangement, the upper closing body 35 is not assigned a control piston. The closing spring assigned to the upper closing body 35 bears here against a suitable shoulder of the bearing body 39 , which has a shoulder which is encompassed by the said shoulder and engages in the closing body 35 and which can be provided with a circulation hole.

The control piston 70 assigned to the lower closing body 25 is designed here as an upper support for the valve spring 24 assigned to the closing body 25 , which is expediently designed here as a disk spring having a steep spring characteristic. The seat body 36 assigned to the upper closing body 35 is here provided with a concentric shoulder 72 which is encompassed by a shoulder 71 , the lower end of which rests on the extension piece 29 which engages in the bore of the closing body 35 and which in turn has an upper flange on the Closing body 25 associated seat part 26 abuts.

The control piston 70 contains a flange 73 which overlaps the upper end of the valve spring 24 and can be supported on the opposite shoulder 71 of the upper seat part 36 , to which a rear collar 74 engaging in a circumferential recess of the upper seat part 36 is connected, and one of which extends from the shoulder 72 of the upper seat part 36 penetrated pipe socket 75 protrudes downward, on which the valve spring 24 is received and guided and the lower end of which engages as a guide socket in the lower, movable spring plate 23 , which rests with a shoulder on the closing body 25 . The flange 73 of the control piston 70 practically forms the upper spring plate associated with the valve spring 24 , which, in contrast to the embodiment according to FIG. 2, is also movable in the axial direction.

To actuate the control piston 70 , a pressure medium can be applied to it in the area of the rear of its flange 73 . For this purpose, the upper seat body 36 is provided with a supply bore 76 which extends from its rear end face, which rests against the seat part 39 , to the shoulder 71 assigned to the flange 73 and communicates with the bore system 65 provided in the seat part 39 . A pressure medium can be applied to the surface of the flange 73 opposite the shoulder 71 , which acts as the piston surface of the control piston 70 . With a corresponding application, a working space is defined which is defined by the piston surface of the flange 73 , the shoulder 71 , the collar 74 and the pipe socket 75 .

The pressure medium supply device provided to act on the control piston 70 can correspond to the arrangement according to FIG. 4 in simple cases in which it is only a question of passivation of the lower closing device 21 at times. In a preferred embodiment, however, the pressure medium supply device can be designed such that, in addition to the possible passivation of the lower closing device 21 , the opening pressure of the lower closing body 24 can also be variably adjusted, that is to say the pressure at which the closing body 25 is lifted from its seat. is adjustable during normal operation. A suitable embodiment of the pressure medium supply device is based on FIG. 7.

The basic structure of the arrangement according to FIG. 7 corresponds to the structure of the arrangement according to FIG. 4. Therefore, only the differences are explained below, the same reference numerals being used for corresponding parts.

FIG. 7 is an embodiment based on 2 three injectors associated with each cylinder 3 in which can be activated by actuation of the actuatable by the control device 60, arranged in the supply lines 59 and shut-off valves passivated. In this respect, there is agreement with the arrangement according to FIG. 4. In addition, in the arrangement according to FIG. 7, in the area of the supply loop 54 a, b, from which the branch lines 58 assigned to the injection valves originate, a control element 77 is provided, by means of which the pressure desired in the supply loop 54 a, b can be set. The control element 77 , which can be designed as an adjustable throttle element, is expediently arranged in the return branch of the supply loop 54 a, b.

The control member 77 can also be controlled by the control device 60 , as indicated by a signal line 78 . The computer of the control device 60 is designed in such a way that in normal injection mode, that is to say in phases in which all three injection valves 3 are operating, the shut-off valves 59 can be activated such that the branch lines 58 are open and the control element 77 is activated in this way that a desired pressure is present in the supply loop 54 a, b, which is below the pressure that is required to keep the closing body 25 in a permanent closed position. Hereby is achieved that the closing body 25 are only lifted from the associated seat when the force generated by the fuel pressure on the closing body 25 exceeds the biasing of the control piston 70 pressure medium to the locking body 25 applied force.

Of course, it would also be conceivable to provide a pressure medium supply device according to FIG. 7 in connection with the arrangement according to FIG. 2 in order to be able to set the opening pressure of the upper closing bodies 35 .

Claims (16)

1. Device for supplying fuel to internal combustion engines, in particular two-stroke large diesel engines, with the injectors ( 3 ) assigned to the cylinders ( 2 ), preferably with several injectors ( 3 ) per cylinder ( 2 ), the injectors ( 3 ) each having at least one to one Have nozzle bore arrangement ( 17 ) leading, to a by means of a pressure source to be pressurized fuel line ( 9 ) flow channel ( 18 ) having at least one under the action of a spring ( 24 , 45 ) against a seat ( 28 , 38 ) and by the fuel when a predetermined fuel pressure from the associated seat (28, 38) can be lifted off closing body (25, 35) passes through, characterized in that at least one of the flow channel (18) by modifying the closing body (25, 35) at least a portion of the injection valves (3) by means of of an associated control piston ( 46 , 70 ) on the respectively assigned Si tz ( 28 , 38 ) can be pressed, whereby the force exerted by the control piston ( 46 , 70 ) on the closing body ( 25 , 35 ) for holding the injection valve ( 3 ) in the permanent closed position is greater than that of the fuel pressure on the closing body ( 25 , 35 ) and less than a force exerted by the maximum permissible fuel pressure on the closing body ( 25 , 35 ). 2. Device according to claim 1, characterized in that the control piston ( 46 , 70 ) can be acted on by means of a preferably hydraulic pressure medium, wherein the action can be switched on and off by means of a valve ( 59 ) which can be controlled in a load-dependent manner by a control device ( 60 ). 3. Device according to claim 2, characterized in that in the case of diesel engines, the control piston ( 46 , 70 ) can be acted on with diesel oil as the pressure medium. 4. Device according to one of the preceding claims 2 or 3, characterized in that at least one group of control pistons (46, 70) have a common, connected to a pressure source (56) provided with a preferably adjustable safety valve (57) supply loop (54) is assigned from which branch lines ( 58 ) leading to the assigned control pistons ( 46 , 70 ), in each of which a valve ( 59 ) controllable by means of the control device ( 60 ) having an input ( 62 ) for load-dependent signals is provided. 5. Device according to one of the preceding claims 2 to 4, characterized in that the control device ( 60 ) for controlling the valves ( 59 ) contains a programmable computer. 6. Device according to one of the preceding claims 2 to 5, characterized in that the pressure piston supply device assigned to the control piston ( 70 ) is designed such that the opening pressure of the assigned closing body ( 25 ) is variably adjustable. 7. The device according to claim 6, characterized in that in the case of injection valves having a plurality of closing bodies ( 25 , 35 ) arranged one behind the other and penetrated by the flow channel ( 18 ), the opening pressure of the closing body ( 25 ) on the outlet side is variably adjustable. 8. The device according to claim 4 and 6 or 4 and 7, characterized in that in the supply loop ( 54 ) by means of the control device ( 60 ) adjustable pressure maintaining member ( 77 ) is arranged. 9. Device according to one of the preceding claims, characterized in that the closing body ( 25 , 35 ) associated, designed as a compression spring ( 24 , 45 ) is supported on the control piston ( 46 , 70 ) assigned to the closing body ( 25 , 35 ) , 10. Device according to one of the preceding claims, characterized in that the control piston ( 46 ) assigned to a first closing body ( 35 ) arranged in the input region of the injection valve ( 3 ) is guided by a guide pin ( 41 ) projecting from a shoulder of a stationary bearing piece ( 39 ). is penetrated, which engages with an axial degree of freedom in the closing body ( 35 ). 11. The device according to claim 10, characterized in that the control piston ( 46 ) is surrounded by a collar ( 40 ) of a seat part ( 36 ) containing the seat ( 38 ) associated with the closing body ( 35 ). 12. Device according to one of the preceding claims 10 or 11, characterized in that the guide pin ( 41 ) is provided with a radial circulation bore ( 48 ) which is open when the control piston ( 46 ) is relieved, and in that the interior of the control piston ( 46 ) which communicates with it. comprehensive collar ( 40 ) of the seat part ( 36 ) communicates with a return line ( 10 ). 13. The device according to one of the preceding claims 2 to 12, characterized in that the control piston ( 46 , 70 ) associated control device ( 60 ) is designed such that in internal combustion engines with several injection valves ( 3 ) per cylinder ( 2 ) at partial load Control pistons ( 46 ) can only be relieved of only a part of the injection valves ( 3 ) provided per cylinder ( 2 ) and the control pistons ( 46 ) of the remaining injection valves ( 3 ) can be pressurized. 14. The apparatus according to claim 13, characterized in that the control device ( 60 ) assigned to the control pistons ( 46 , 70 ) is designed such that the control pistons ( 46 ) of the injection valves ( 3 ) provided per cylinder ( 2 ) are at a predetermined load at partial load Alternating cycles can be pressurized and relieved. 15. The apparatus according to claim 14, characterized in that the control pistons ( 46 , 70 ) of the injection valves ( 3 ) provided for each cylinder ( 2 ) can be alternately pressurized and relieved at intervals of a maximum of two minutes. 16. The device with the structure according to one of the preceding claims, characterized in that for increasing the fuel injection pressure, the force exerted by the control piston ( 70 ) on the closing body ( 25 ) is less than the force for holding the closing body ( 25 ) in the permanent closed position is.