EP1252432B1 - Directly controlled fuel injection device for a reciprocating internal combustion engine - Google Patents

Abstract

The invention relates to a fuel injection device for a reciprocating internal combustion engine, comprising a nozzle part (5) with an injection nozzle (13), said nozzle part having a pressure chamber (10) in which a nozzle needle (9) that closes the injection nozzle needle (13) is guided. Said nozzle needle can be moved into the opening position when subjected to pressure by the fuel to be injected. The pressure chamber (10) is connected to a control pan (7) by a connecting channel (6), this control part having a valve chamber (21) into which the connecting channel (6) and a high pressure channel (8) that is connected to a fuel supply (4) open, and in which a valve body (23) is guided. Said valve body (23) acts as a piston system and is held in the closing position by a valve spring and a valve seat (22). The nozzle part also comprises an actuator part (20) which is functionally connected to the valve body (23) and which when activated, moves said valve body in the opening direction and releases the through-flow from the high pressure channel (8) into the connecting channel (6).

Description

As so-called common rail systems formed fuel injectors for a reciprocating internal combustion engine with Direct fuel injection consist essentially of a Nozzle part with injector, one injector having closing nozzle needle, the pressurization through the fuel to be injected via a servo-hydraulic system is movable in the open position. The required Form is via the high-pressure part of the fuel supply, d. H. taken off the common rail. About the print preset In the common rail, the injection pressure can be influenced very flexibly and via the control of a servo valve and Thus, the nozzle needle can be injection time and injection duration also set with high flexibility.

However, if you want with the previously known systems not only the Injection amount by a corresponding control of the opening time but you also want the injection rate shapes, d. H. the injection quantity per unit time during the Opening time vary, so the stroke of the nozzle needle must be controlled become. Here, however, the hydraulic energy of the flowing fuel immediately before the injection hole of the Injection nozzle by the so-called seat throttling, the front everything occurs at a smaller needle stroke, converted into turbulence, because of the stroke-dependent changing free flow cross-section between the nozzle needle and the nozzle needle seat as Throttle acts. The resulting increased turbulence of the flowing fuel in the injection hole influenced the mixture formation, so that there is no "real" rate control results. This is in direct fuel injection, d. H. when injecting the fuel directly into the cylinder space disadvantageous. As a consequence, above-described turbulence increase is for small injection quantities, for example Injection quantities, for example, a near-jet burning the injected fuel quantity has been determined by the the course of the combustion process adversely affected becomes.

From US-A-5,526,791, DE-A-43 41 546 and DE-U-297 17 649 are Fuel injectors known, each one Valve body, which by an activated actuator is displaceable in the open position and the fuel flow releases under high pressure. If the actuator is disabled, a return spring pushes the valve body in the closed position back.

The invention is based on the object, a fuel injection device for a direct fuel injection which makes it possible during the respective injection time to vary the injection quantity, d. H. the injection rate to shape.

This object is achieved by a fuel injection device for a reciprocating internal combustion engine with a nozzle part with injection nozzle, which has a pressure chamber, in the a nozzle needle closing the injection nozzle is guided, when pressurized by the fuel to be injected is movable in the open position, wherein the pressure chamber via a connection channel with a control part in connection stands, which has a valve chamber into which the connecting channel on the one hand and one with the fuel supply connected high-pressure channel on the other hand opens and in the a valve body acting as a piston system is guided, the by a valve spring on a valve seat in the closed position is held, and with an actuator connected to the valve body is in operative connection and this when activated moved into predetermined opening positions and a corresponding Flow from the high-pressure channel into the connecting channel releases, as well as with a compensation piston of the above Pressure in the connecting channel in the opposite direction to the force effect of the actuator can be acted upon.

In the fuel injection device according to the invention the nozzle part designed so that when pressurized the Nozzle needle the passage cross-section to the nozzle openings as completely as possible, with intermediate positions are not provided. The control of the volume flow takes place via the valve body provided in the control part, the Hub by a corresponding control of the actuator can be varied. The valve body is in this case preferably designed as a seat valve to the tightness in the closed Condition. The actuator is here Appropriately designed so that he is in relation to his Adjusting travel proportional to the applied job energy is trained. For this purpose, in particular electrical Actuators that are voltage-proportional with respect to their travel are formed adjusting, as for example given by so-called solid state actuators are. As solid state actuators come here in particular piezoelectric Actuators but also magneto-strictive actuators into consideration. Also electromagnetically working actuators can be used. Here, the arrangement of a in its diameter correspondingly sized compensating piston advantageous, over the pressure in the connecting channel is acted upon the nozzle part and accordingly against the force of the actuator acts. This results in a so-called Pressure feedback, the good controllability of from the high pressure side in the connecting channel flowing volume flow and thus allows a good shaping of the injection rate.

It is particularly useful if in one embodiment of Valve body on a side facing away from the actuator end with a Compensating piston is provided, which exceeds the pressure in the connecting channel can be acted upon.

In an embodiment of the invention, it is provided that the control part a to the low pressure side of the fuel supply opening Relief valve has, which the connection channel is assigned, and the activation of the actuator closes. By the arrangement of such a relief valve Care is taken to ensure that immediately when putting on of the valve body in the control part on its valve seat the pressure in the connecting channel to the nozzle part degraded quickly is, so that the nozzle needle very quickly in her Closed position is performed.

In a particularly advantageous embodiment of the invention further provided that the control part has a pressure divider, the one with the high-pressure channel on the one hand and a piston system forming valve body with compensating piston on the other communicates and the over the actuator is adjustable. By the arrangement of such a pressure divider in the control section it is possible to choose the one you want Set injection pressure dynamically. Depending on the design the arrangement can be made so that depending on the type of the actuator used via the travel of the actuator or via the force of the actuator, the injection pressure before a set pressure-controlled injection nozzle.

Further features and embodiments of the invention are the Claims and the following description of exemplary embodiments refer to.

Fig. 1

ein Schaltschema einer Kraftstoffeinspritzeinrichtung,

Fig. 2

ein Ausführungsbeispiel für ein Kraftstoffeinspritzventil mit Düsenteil und Steuerteil,

Fig. 3

eine abgewandelte Ausführungsform des Steuerteils,

Fig. 4

eine weitere Abwandlung des Steuerteils,

Fig. 5

in größerem Maßstab das Detail A in Fig. 4,

Fig. 6

eine abgewandelte Ausführungsform mit einem in den Steuerteil integrierten Druckteiler,

Fig. 7

den Druckteiler gem. Fig. 6 in größerem Maßstab,

Fig. 8

eine Ausführungsform des Druckteilers mit Stützkolben,

Fig. 9

eine Ausführungsform des Druckteilers mit hydraulischem Wegübersetzer,

Fig. 10

eine Ausgestaltung der Kraftstoffeinspritzdüse mit einer Zwei-Feder-Abstützung,

Fig. 11

eine Ausführungsform der Kraftstoffeinspritzdüse mit Ausweichkolben.

The invention will be explained in more detail with reference to schematic drawings of exemplary embodiments. Show it:

Fig. 1

a schematic diagram of a fuel injection device,

Fig. 2

an embodiment of a fuel injection valve with nozzle part and control part,

Fig. 3

a modified embodiment of the control part,

Fig. 4

a further modification of the control part,

Fig. 5

on a larger scale, the detail A in Fig. 4,

Fig. 6

a modified embodiment with an integrated in the control part pressure divider,

Fig. 7

the pressure divider acc. 6 on a larger scale,

Fig. 8

an embodiment of the pressure divider with support piston,

Fig. 9

an embodiment of the pressure divider with hydraulic path translator,

Fig. 10

an embodiment of the fuel injection nozzle with a two-spring support,

Fig. 11

an embodiment of the fuel injector with bypass piston.

In Fig. 1 is a fuel injection device in the form of a flow chart for direct injection of the fuel in the individual cylinders of a reciprocating internal combustion engine shown. The fuel injector has a fuel supply 1, essentially by a fuel tank 2, a high pressure pump 3 and a high pressure chamber 4, the so-called common rail.

Each cylinder of the reciprocating internal combustion engine is equipped with a nozzle part 5, which via a connecting channel 6, a Control part 7 and a high pressure passage 8 with the fuel supply 1 communicates. The control part 7 is also available with a motor controller not shown here in connection, by acting as the control valve Control part 7 can be controlled so that the injection time the connection between high-pressure channel 8 and connecting channel 6 is opened and the high pressure Fuel can act on the nozzle part 5. The special one Functionality will be described in more detail below.

The nozzle part 5 is essentially formed by a nozzle needle 9, which is guided in a pressure chamber 10, in which Connecting channel 6 opens. The nozzle needle 9 has a needle tip 11 on, with a corresponding seat 12 of the Injector 13 cooperates and acts as a valve. The injector 13 is provided with corresponding nozzle openings 14. On the needle tip 11 side facing away from the nozzle needle 9 provided with a piston body 15, on the one Closing spring 16 acts in the closing direction. Will about the Control part 7, the connection between the high-pressure channel 8 and Connecting channel 6 open and the pressure chamber 10 and thus the piston body 15 is pressurized, then raises the nozzle needle 9 from its valve seat 12, so that the fuel from the pressure chamber 10 through the nozzle openings 14 in the Combustion chamber of the relevant cylinder of the reciprocating internal combustion engine can emerge as a fine mist. Once on the control section 7 closed the connection to the high-pressure chamber 4 is, is on the closing spring 16, the nozzle needle 9 again pressed on its valve seat and the fuel supply stopped.

When returning the control part 7 in its closed position is a connection between the connecting channel 6 and a Low pressure channel 17 is opened, so that the pressure chamber 10th Relieves pressure and the nozzle needle quickly in her Closed position can be returned. The as injection valve acting nozzle part 5 is in the embodiment designed so that he pressurized the injector 13 completely opens and closes when pressure is released, so that according to the control via the control part 7 a Timely opening and closing of the injector ensured is. In the arrangement of two shown in FIG Closing springs 16.1 and 16.2 with different spring stiffness is to achieve that the nozzle needle 9 pressure-dependent two opening positions can take.

The closing spring 16 is arranged in a leakage space 18, the via a leakage line 19 with the low pressure line 17th is in communication, so that the accumulating in the leakage chamber 18 Leakage amounts are derived in the fuel tank 2 can.

The actuator 20 is preferably designed to be in relative to its travel proportional to the applied Job-setting energy is designed. In a training of the control part 7, for example, as a throttle valve so given the opportunity that from the high pressure channel. 8 in the connecting channel 6 effluent flow through corresponding adjustment of the opening cross-section in the control part 7 to influence. As at a pressurization designed as an injection valve nozzle part 5 in the illustrated schematic example completely opens, can via a corresponding change in the setting of the control section 7 of the nozzle part 5 supplied volume flow during the opening duration of the injection nozzle 13 can be varied.

Structure and function of the control part 7 will be described below of different embodiments explained in more detail become.

The actuator 20 is advantageous as a so-called solid state actuator educated. In this case, a piezoelectric is preferred working actuator used in relation to its travel or, because of its mechanical compliance, its adjusting force proportional to the voltage is trained. Instead of a piezoelectric actuator it is also possible to use a magnetostrictive actuator, the current-proportional adjusting with respect to its travel is trained. As such solid state actuators by a high switching speed, good controllability the Stellweges and also large Stellkräfte excel and In addition, directly or possibly via a hydraulic Stroke translation acting on the control part in the control part 7, also results in only short opening times for as Injector valve formed nozzle part 5 the possibility of targeted shaping of the injection rate, d. H. a targeted Change in during the opening time of the injector introduced into the combustion chamber of the cylinder concerned Volume flow.

While it is possible in principle, the nozzle part 5 and the Use control part 7 as separate units, is in Fig. 2 shows an embodiment shown in the nozzle part. 5 and control part 7 with actuator 20 designed as a unit are. The description of this embodiment is also the above-indicated specifics in the training to remove the control part 7. For already described components Reference numerals used in FIG. 1 are also shown in FIG. 2 taken over, so that reference can be made.

As can be seen from Fig. 2, there is the overall arrangement from a carrier body constructed in several parts for reasons of production, by a coaxial assignment of nozzle part 5, Control part 7 and actuator 20 is marked.

The control part 7 has a valve arrangement 21.0 with a Valve chamber 21.1, in the high-pressure channel 8 on the one hand and the connecting channel 6 on the other side. The valve room 21.1 is provided with a valve seat 22 to which a formed as a piston system valve body 23 via a valve spring 24 held with its valve member 23.1 in the closed position is, so that the high pressure passage 8 with respect to the connecting channel 6 is locked. The for the valve spring 24th required space is connected to the leakage line 19. The sections 23.1, 23.2, 23.3 and 23.4 have here partly different diameters.

On the side facing away from the valve spring 24 acts on the Valve body 23 of the actuator 20, which in the illustrated here Embodiment as a piezoelectric actuator is trained. The piezoelectric actuator 20 is in essentially formed by a stack of piezoelectric Body 20.1, with a not shown here, controllable Voltage source are connected and the one end supported on a housing part 20.2 and the other end on a Act transfer piston 20.3. The transmission piston 20.3 is associated with a hydraulic chamber 20.4, which in itself known manner with a liquid, here with fuel, is filled.

Control part side, the hydraulic chamber 20.4 is a pressure piston 23.1 associated with the valve body 23 in connection stands. If the piezoelectric body 20.1 with a voltage is applied, then the transfer piston 20.3 in Direction advanced to the hydraulic chamber 20.4 and then is under the action of contained in the hydraulic chamber 20.4 Fluid also the pressure piston 23.1 moved. Thereby, that the pressure piston 23.1 has a smaller diameter as the transmission piston 20.3, this results in a Stroke translation, d. H. according to the diameter ratio the valve body 23 via a relative to the voltage proportional Extension of the piezoelectric body 20.1 moved accordingly longer way.

The change in length of the piezoelectric body 20.1 takes place voltage proportional, so that according to the applied Voltage of the valve body 23 with its valve member 23.1 From the valve seat 22 lifts and thus a corresponding Flow cross-section releases, so that from the high-pressure channel 8 in the connecting channel 6 a throttling between the valve seat 22 and valve part 23.1 corresponding volume flow can pass, which then raises the nozzle needle 9 and the Injector 13 releases. According to the valve part 23.1 approved opening cross section and according to the Duration of opening then enters fuel through the nozzle openings 14 in the combustion chamber of the cylinder in question. Becomes reset the voltage on the piezoelectric body 20.1, is the valve member 23.1 on the valve seat via the valve spring 24 22 pressed and thus inhibited the fuel supply.

At the nozzle-side end of the valve body 23 is a compensation piston 25 arranged, the smaller diameter has as the valve member 23.2. The compensation piston 25 can, as shown, connected to the valve body or be separated from the valve body. This compensation piston 25th is through a branch line 26 of the connection channel 6 through the pressure prevailing in the connecting channel 6 pressure applied. This results in a force feedback via the pressure in Closing direction of the valve body 23, ie against the force of the actuator 20. This causes the valve body 23 not exclusively by the valve spring 24 against the force of the actuator 20 acts, but by the force feedback it is ensured that the valve body 23 during its longitudinal movement both in the opening direction as well as in the closing direction without play and without delay every change in length of the actuator adapts and thus a Energy-dependent in the case of a piezoelectric actuator voltage dependent, length change exactly to the movement of the Valve body 23 can be transferred. oscillatory movements are suppressed. By the vote of the different, exposed to the pressurization diameter or Surfaces, so the diameter of the guide parts 23.3 and 23.4 of the valve body and the diameter of the compensating piston 25, the degree of force feedback can be dimensioned. With a large degree of feedback, the controllability becomes better, but requires stronger actuators.

This force feedback allows, instead of a piezoelectric Actuator a simple electromagnetic Use actuator in which the force is proportional to the Energy supply is and thus also a defined admission the injection nozzle is possible.

The low-pressure channel 17, which with a partial length 17.1 in Valve body 23 continues and the low pressure passage 17 with the Connecting channel 6 connects, is with a relief valve 27, which is shown here as a simple ball valve is. As between the transfer piston 20.3 and the pressure piston 23.1 arranged in the hydraulic chamber 20.4 a tension spring 20.5 is, is in the idle state, the pressure piston 23.1 via a Tension spring 20.5 acting on the relief valve 27 as Ball pressed and this held in the closed position.

If the actuator 20 is acted upon and the valve body 23 in Opening position shifted (arrow 28), the relief valve 27 held in the closed position. When switching off the electrical voltage on the actuator 20 shortens this abruptly its length, so that due to the inertia and the im Connecting channel 6 pending injection pressure of the transmission piston 23.1 is raised by the ball and so the Passage cross section is released. This can be the In the connecting channel 6 still pending injection pressure on the Low pressure channel 17 to the fuel tank 2 down quickly degrade reduce, so that the nozzle needle 9 via the closing spring 16 is brought to the closed position in a timely manner.

By an appropriate vote of the relief valve can be achieved that the pressure in front of the nozzle is not complete is degraded, but a residual pressure remains, thereby a vapor bubble formation is avoided.

In Fig. 3 is a modified embodiment of the basis 2 described control part 7. Same Components are identified by like reference numerals. The structure of the embodiment acc. Fig. 3 corresponds substantially the structure described with reference to FIG. Of the Difference on the one hand is that the valve body 23rd is integrally formed and actuator side of the pressure piston 23.1 firmly connected to the valve body 23. The pressure piston 23.1 has a smaller diameter than the piston parts 23.2 and 23.3.

In the embodiment according to. Fig. 3 is a relief valve 27 provided a hydraulic seat valve whose piston part 27.1 presses a valve needle 27.2 on its sealing seat, so that the connecting line 6 with respect to the low-pressure channel 17th is locked. Upon actuation of the valve is on the Pressure build-up in the hydraulic chamber 20.4 the closing force of the relief valve 27 pressure proportional increases and so the relief valve 27 reliable against the injection pressure in Connecting channel 6 held in the closed position. Will the actuator set tensionless and shortens its length, then extends the pressure reduction in the hydraulic chamber 20.4 on the one hand and the still under injection pressure fuel in the connecting channel 6 off to the relief valve 27 in the short term against the force of a trained as a plate spring closing spring 27.3 to open, as well as the pressure reduction in the connecting channel 6 to ensure the low pressure channel 17.

FIG. 4 shows a further embodiment of the control part 7 shown. The structure essentially corresponds to the structure the embodiment described with reference to FIG. 3, so that can be referenced. The difference is here only in that no separate relief valve is provided, but that the valve body 23 in the area his serving as a pressure piston 23.1 end as a relief valve 27 is designed and designed for this purpose as a slide valve is. As is apparent from the enlarged view in FIG. 5 see, is serving as a pressure piston 23.1 end of the valve body 23 at its end facing the valve chamber 21 Tapered shaped or with a sloping plane or groove and in such a way that in the closed position of Valve body 23, the actuator-side end of the cone part 27.4 in a communicating with the low pressure passage 17 Annulus 27.5 projects and in this case a passage cross-section leaves free.

Once on the actuator 20, the valve body 23 in the open position (Arrow 28) is moved, the annulus 27.5 completed with respect to the valve chamber 21, so that accordingly the opening of the passage cross-section at the valve seat 22 fuel from the high pressure passage 8 in the connecting channel 6 can flow over and here the injection pressure builds.

If the actuator 20 is de-energized, then moves the valve body 23 under the force of the closing spring 24 and the pressurization via the compensation piston 25 in the direction of the valve seat 22. In this case, then the Passage cross section at the annular space 27.5 released, so that the pressure in the connecting channel 6 can be reduced. The order is here dimensioned so that the release of the passage cross-section to the annulus 27.5 virtually simultaneously with the seating of the locking part 23.2 on the valve seat 22nd is released.

Also in the embodiment described by Fig. 3 of the Relief valve 27 can by appropriate dimensioning the pressure reduction at the injection valve are guided so that a vapor bubble formation is avoided. In the described in Fig. 4 Embodiment, this can be achieved by an additional, reached on line 17 connected pressure relief valve become.

The embodiments described with reference to FIGS. 3 and 4 the control part 7 can be used in the same way as described with reference to FIG. 2, namely as a structural unit combined with a nozzle part 5. It is also possible, as shown in the schematic diagram. Fig. 1 can be seen is, for all types of the control part 7 an arrangement to meet, in which the control part 7 separated from the nozzle part 5 is arranged. Accordingly, in the schematic Presentation acc. Fig. 1 leading to the control part 7 Branch line 26 indicated by dash-dotted lines.

In the following figures 6 to 9 is a modified Embodiment of the injection nozzle acc. Fig. 2 in the form of a Flow diagram shown, with only the functionally essential Parts are reproduced in detail. Same components are again provided with the same reference numerals, so that on the above description of the other embodiments both in terms of structure and in terms of Function can be referenced.

In the embodiment according to. Fig. 6 is the valve assembly 21.0 upstream of a so-called pressure divider 30. In Fig. 7 is on an enlarged scale an embodiment of the pressure divider 30 is shown. The pressure divider consists essentially of a piston body 31, with its upper end with the actuator 20 is in operative connection (arrow 20 in Fig. 7) and the at its lower end via a spring plate 32 a return spring 33 is supported. The piston body 31 is with a valve body 34 provided with a first valve seat 35.1 cooperates. In depressurized state of the Valve body 34 by the return spring 33 to the first Valve seat 35.1 pressed.

The valve body 34 is facing on its return spring 33 Side assigned a second valve seat 35.2, the connects the annular space 37 with the outflow space 39, and the Valve body 34 closes the more, the further he moves in Direction of the arrow 20 moves. Thus, the valve body forms 34 with the valve seats 35.1 and 35.2 a 3/2-way proportional valve with 100% negative coverage. Through this Arrangement increases the pressure in the annulus 37 approximately linear with the travel of the valve body 34 of 0 bar, when the valve body abuts against the valve seat 35.1, up to the in the line 8 prevailing pressure when the valve body to abuts the valve seat 35.2. Depending on the diameter of the Valve seat 35.2 takes place a feedback of the pressure in the annular space 37 on the actuator 20 so that an electromagnetic Actuator can be used. The valve seat 35.2 can be designed as a flat seat to meet the requirements to minimize the manufacturing accuracy.

The valve body 34 is associated with a first annular space 36, in which opens a branch 8.1 of the high-pressure line and by the closed position defined by the valve seat 35.1 is completed. The valve body 34 is in one second annular space 37 arranged, which via an overflow line 8.2 is in communication with a pressure chamber 38, the through the valve body 23 on its return spring 24th the opposite side is limited. The valve body 34 is further in the region of the return spring 33, an outflow space 39 is assigned, the via a discharge line 40 with the low-pressure channel 17 is connected.

The pressure chamber 38 is connected via a line to a pressure chamber 41 in connection, the piston part 27.1 of the relief valve 27 is assigned.

Is the valve body via a piezoelectric actuator 34 from its valve seat 35.1 by the energization given measure lifted, then flows out of the High-pressure channel 8 via the connecting line 8.1 fuel with correspondingly high pressure in the annular space 36 and flows via the connecting line 8.2 in the pressure chamber 38 via. As a result, the valve body 23 against the force of the return spring 24 shifted in proportion to the pressure, and the flow opened to the connecting channel 6 to the injection valve 5 accordingly. The prevailing in the connecting channel 6 injection pressure also acts on the spring 24 side facing the Valve body 23, the pressure-loaded surface just as large is like the pressure-loaded surface of the space 38 facing Side of the valve body. Because the force of the spring 24 in comparison is small to the applied compressive forces, opens the Valve body 23 always so far until the pressures in the space 38th and the connecting channel 6 are the same.

Due to the above-described function of the pressure divider 30th the injection pressure can be modulated during the injection be controlled by the actuator 20 just so far, that he the valve body 34 in a position between the two Valve seats 35.1 and 35.2 moves in the annular space 37th and thus also in the space 38 sets the pressure, as Injection pressure is desired. The pressure in the annular space 3 is also in the pressure chamber 41 on the piston body 27.1 of the relief valve 27, so that this pressure, the closing spring 27.3 in the closing direction supporting the valve body 27.2 works.

When the actuator 20 is deactivated, the valve body 34 is seated of the pressure divider 30 on its valve seat 35.1, so that the pressure chambers 41 and 38 are depressurized and thus the Valve arrangement 21.0 closes. The still in the connection channel 6 Pending pressure can be through the line 17.1 and the relief valve 27 are degraded very quickly, so that the valve spring 16, the nozzle needle 9 very quickly in the closed position brings, wherein the valve spring 27.3 is designed so that the fastest possible pressure reduction, on the other but a residual pressure remains so that vapor bubbles are formed is avoided.

The embodiment acc. Fig. 8 is with respect to the control part 7 identically constructed in the function as the above Embodiment acc. Figs. 6 and 7. The difference only consists in that the piston body 31 of the Pressure divider 30 at its the return spring 33 facing End is provided with a compensation piston 42, the over one of the overflow 8.2 branching branch line with the partial pressure can be acted upon and so a pressure feedback can be done. This allows the pressure divider 30 in the direction of the arrow via an electromagnetic actuator to press.

The modification shown in Fig. 9 corresponds substantially the above-described structure gem. Fig. 6 and 7. The control part 7 is modified only in such a way that the pressure chamber 41 of the relief valve via a throttle 43rd is directly connected to the low pressure passage 17 and the Pressure divider 30 here are designed as a 2/2-way valve can.

In the embodiment according to. 9, the pressure divider 30th not acted upon directly by the actuator 20, but via a hydraulic distance translator 43, as he is based on the embodiment of Fig. 2 and 3 is already described. about a feed line 44 will be the inevitable leakage losses balanced in the hydraulic space of the hydraulic position transmitter. The described path translation can-with all described Variants of the injection system can be combined.

In Fig. 10 is an embodiment of the injection valve with an openable in two stages nozzle needle 9 shown. The Nozzle needle 9 is supported by a first soft Closing spring 16.1 on the housing. Furthermore, a sliding body Provided 16.3, which turned away with his the nozzle needle 9 Side on a second harder closing spring 16.2 supported. The sliding body 16.3 has a support extension 16.4 on, in the closed position of the nozzle needle 9 by a small Dimension a before the end of the piston body 15 of the nozzle needle 9 ends.

Is via the connecting channel 6 of the pressure chamber 10 with a Pressure is applied, which is less than the restoring force the return spring 16.2, then the injector opens only by a stroke corresponding to the dimension a. When the pressure chamber 10 is subjected to a pressure that is greater than that Restoring force of the closing spring 16.2, then the nozzle needle 9 pushed back accordingly and the injection valve fully open.

In Fig. 11, a modification of the embodiment is gem. FIG. 10 is shown. In this embodiment, the supports Closing spring 16 on a bypass piston 16.5, on his the closing spring averted side has a pressure chamber 16.6, via a throttle 16.7 to the connecting channel. 6 connected. About this arrangement is a pressure-dependent dynamic guidance of the opening movement of the nozzle needle. 9 possible.

With a fuel injection device of the invention It is possible, even with high-speed diesel engines, in particular diesel engines for passenger cars, the under full load speeds from 4,000 to 4,500 revolutions per Minute and where high injection pressures from about 1,500 to 2,000 bar, short injection times of 1.5 milliseconds, for example by a direct control of the control part.

Claims (14)

1. A fuel injection means for an internal combustion piston engine, comprising a nozzle part (5) with an injection nozzle (13), which part has a pressure chamber (10) in which a nozzle needle (9) which closes the injection nozzle (13) is guided, which needle, when acted upon by pressure by the fuel to be injected, can be moved into the open position, the pressure chamber (10) being connected via a connecting channel (6) to a control part (7) which has a valve chamber (21) into which the connecting channel (6) on one hand and a high-pressure channel (8) connected to a fuel supply means (4) on the other hand open and in which a valve body (23) acting as a piston system is guided, which body is held in the closed position on a valve seat (22) by a valve spring (24), and comprising an actuator (20) which is in an operative connection with the valve body (23) and upon activation moves it in the opening direction and enables a flow through the high-pressure channel (8) into the connecting channel (6), and comprising a compensating piston (25; 42) which can be acted upon via the pressure in the connecting channel (6) counter to the action of force of the actuator.
2. A fuel injection means according to Claim 1, characterised in that the compensating piston which can be acted upon via the pressure in the connecting channel (6) is located on the valve body (23) on its end (25) remote from the actuator (20).
3. A fuel injection means according to Claim 1 or 2, characterised in that the connecting channel (6) is provided with a relief valve (27) which opens on the low-pressure side (17) of the fuel supply means (4) and which is closed when the actuator (20) is activated.
4. A fuel injection means according to Claims 1 to 3, characterised in that a tension spring (20.5) is arranged between the actuator (20) and the valve body (23).
5. A fuel injection means according to one of Claims 1 to 4, characterised in that the actuator (20) has a transmission piston (20.3) and the end of the valve body (23) facing the actuator (20) has a pressure piston (23.1) and that a hydraulic chamber (20.4) is arranged between the two pistons, the diameter of the pressure piston (23.1) being smaller than the diameter of the transmission piston (20.3).
6. A fuel injection means according to one of Claims 1 to 5, characterised in that the diameter of the compensating piston (25), depending on the desired force feedback, is less than, equal to or greater than the diameter of the part of the piston system of the valve body (23) which acts in the opening direction when pressure is supplied.
7. A fuel injection means according to one of Claims 1 to 5, characterised in that the actuator (20) in respect of its actuated distance is designed to be proportional to the applied actuating energy.
8. A fuel injection means according to one of Claims 1 to 7, characterised in that an electric actuator (20) is provided which in respect of its actuated distance is designed to be proportional to voltage.
9. A fuel injection means according to one of Claims 1 to 7, characterised in that an electric actuator (20) is provided which in respect of its actuated distance is designed to be proportional to current.
10. A fuel injection means according to one of Claims 1 to 9, characterised in that the control part (7) has a pressure divider (30) which is connected to the high-pressure channel (6) on one hand and to the valve body (23) forming a piston system with a pressure equalisation piston (23.1; 42) acting as a compensating piston on the other hand, which piston can be acted upon by the pressure acting in the connecting channel (6) counter to the actuator force and which is adjustable via the actuator.
11. A fuel injection means according to one of Claims 1 to 10, characterised in that the pressure divider (20) is in an operative connection with the relief valve (27).
12. A fuel injection means according to one of Claims 1 to 11, characterised in that the relief valve (27) has a valve spring (27.3) which acts in the direction of closure on a valve body (27.2), and also a piston (27.1) which can be additionally acted upon in the closing direction via the pressure divider (30).
13. A fuel injection means according to one of Claims 1 to 12, characterised in that the pressure divider (20) is in the form of a 3/2-way valve, the two valve seats of the 3/2-way valve representing the two choke points of the pressure divider.
14. A fuel injection means according to one of Claims 1 to 13, characterised in that the valve seat (35.2) of the pressure divider (20) is in the form of a flat seat.

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