EP1991773B1 - Fuel injection valve for internal combustion engines - Google Patents

Description

The present invention relates to a fuel injection valve for the intermittent injection of fuel into the combustion chamber of an internal combustion engine according to the preamble of patent claim 1, which is preferably used in diesel engines.

Fuel injection valves of this type are for example from the WO 2005/019637 A1 known. Further fuel injection valves are for example in WO 02/053904 A1 . EP 0 976 924 B1 and DE 37 00 687 A1 disclosed.

In the WO 02/053904 A1 an injection valve with a piezoelectric actuator is shown, which controls an outlet of a valve chamber. The valve chamber is connected via an outlet throttle passage with a control chamber and this control chamber is connected via an inlet throttle passage with a high pressure chamber of the injection valve. By lowering the pressure in the control chamber, the end face of a control piston of the injection valve member is relieved, whereby the injection valve member can be opened and the injection of fuel can take place. To close the injection valve member at the end of the injection can be opened by the piezoelectric actuator another connected to the high-pressure chamber passage, whereby the inflow of fuel into the control chamber in addition to the intake throttle passage can also take place through the Auslassdrosseldurchlass. This solution is quite expensive, as to achieve a exact and with many injectors always same opening movement of the injection valve member, which must be the case in a series of identical injectors, first, a precise adjustment of the flow characteristics of both the inlet and the outlet throttle passage must be achieved. Second, in addition, the further passage must be selectively opened by the piezoelectric actuator to make the closing of the injection valve member at the end of the injection at least so fast that the combustion of the injection valve assigned to the engine cylinder does not suffer greatly. Since the additional inflow to realize the closing movement of the injection valve member but must flow through the Auslassdrosseldurchlass, it is throttled and the additional, opened by the actuator cross section, only used to a small extent.

When in the EP 0 976 924 B1 disclosed injector are, analogous to from the WO 02/053904 A1 known injection valve, an inlet and an outlet throttle passage with the same function and equal disadvantages present. This solution is to be preferred in that the actuator valve member simultaneously closes the additional further passage when the valve chamber is opened. This function corresponds to that of a three-way valve, so it has long been known in hydraulics. The further passage is designed as a flat seat, whereas the outlet from the valve chamber is designed as a conical seat. Because of the small stroke of the actuated by the piezo actuator valve member is created by the conical seat, the difficulty to obtain equal strokes in all injectors of a series. Furthermore, the orientation of the mushroom-shaped Valve member problematic, because the flat seat is disposed in a first intermediate plate and the conical seat in a second intermediate plate of the injection valve, wherein the valve member is guided radially in the first plate. Both intermediate plates must therefore be positioned exactly to one another, otherwise the tightness of at least one of the seats is prejudiced.

At the time of the DE 37 00 687 A1 known injection system connects during the injection of a solenoid valve in its operation a channel with a return line. Between the channel and a control chamber is designed as a plate with a throttle bore check valve. During the opening movement of the injection valve member, the control chamber can empty only via the throttle bore of the check valve plate in the channel, resulting in a controllability of the opening movement of the injection valve member. When closing the injection valve member opens the check valve plate so that the closing movement of the injection valve member can take place faster than the opening movement. Also in this injection system, the fuel flow must flow to close the injection valve member alone by a throttle, which connects the channel via an annulus with a pressure accumulator of the injection system. This throttle is tuned by small cross-section and with another throttle, which is located at the output of the channel. The opening and closing movement of the injection valve member is thus controlled by three throttle bores, which must be precisely matched.

From the WO 2005/019637 A1 and in particular Fig. 9 a fuel injection valve is known in which the opening movement of the injection valve member, analogous to in the DE 37 00 687 A1 disclosed injection valve, can be determined by designing a throttle bore. To end the injection process, the piezo actuator of a pilot valve must expand, which results in a high-pressure inlet connected to the high pressure passage is released by a control body. The released, relatively large cross section causes a large fuel flow into the control chamber and thus a particularly rapid and advantageous closing of the injection valve member. To release the control body, a transmission pin is pressed by a pilot valve pin of the actuator on the front side of the control body.

In this solution, it is unfavorable that the piezo actuator must expand during the closing process of the injection valve member. In this state, a piezo actuator is energized. Since the duration of injection is only 5% or less of the duration between two injections, the piezoactuator is almost constantly under electrical voltage. Furthermore, in this known solution, the position of the throttle bore, which determines the opening movement of the injection valve member, unfavorable, since it is located far away from the control room.

The document DE 10 2005 020 048 A1 discloses an injector having a structure for controlling a nozzle needle. A valve back pressure chamber is provided to apply a back pressure of a first valve needle. In addition, a hydraulic pressure passage is provided so as to extend through the valve back pressure chamber. A valve body is provided on a second valve needle and is driven to connect and disconnect between the hydraulic pressure passage and a fuel tank, thereby driving the first valve needle. The second valve needle is driven by a hydraulic pressure caused by an actuator.

Object of the present invention is to provide a fuel injection valve of particularly simple construction, in which both a controllability of the opening movement of the injection valve member and a rapid closing of the injection valve member can be achieved with a minimum construction cost. Furthermore, the fuel injection valve of the present invention, the realization of multiple injections can be easily achieved with a very short time interval.

While a control chamber and a valve chamber are permanently connected to each other via an exact throttle passage, an intermediate valve separates these two spaces continuously from one another. The throttle passage is disposed immediately adjacent to the control room. A passage of large cross-section, connected to the high-pressure chamber of the injection valve and leading into the control chamber, compared with the cross section of the throttle passage, is controlled by the intermediate valve. Since the cross section of the controlled by an electric actuator assembly outlet from the valve chamber can also be substantially larger than the cross section of the throttle passage, the opening movement of the injection valve member is substantially solely dependent on the cross section of the throttle passage. When closing the outlet from the valve chamber by means of the actuator assembly, the intermediate valve opens quickly and releases the passage of large cross-section connected to the high-pressure chamber, which causes a rapid termination of the injection process.

In a preferred further embodiment of the present invention, acting as a 2/3 way valve flat seat valve member is used, which can perform a certain, small stroke in a second intermediate plate in the valve chamber. In a preferred embodiment, the flat seat valve member has two flat seats. In the de-energized state of a piezoactuator advantageously used to actuate the flat seat valve member, the flat seat valve member closes with a first valve seat, a connection between the valve chamber and the low-pressure fuel return from and at the same time releases a located in a first intermediate plate, connected to the high-pressure inlet high pressure passage of relatively large, unthrottled cross section. The passage cross section between the flat seat valve member and the high pressure inlet, ie the valve seat, is dependent on the distance, thus the stroke of the flat seat valve member and usually represents a narrower passage than that of the high pressure passage.

In the energized state of the piezo actuator, when it expands, the flat seat valve member is pressed against the high pressure passage and closes the valve passage with its valve seat, at the same time the low pressure outlet is released. A second connecting channel of relatively large cross-section in the first intermediate plate connects the control chamber with the valve chamber.

Terms such as "relatively large cross section" or "cross section greater than" and the like refer to the cross section of the said throttle passage and such cross sections are preferably at least twice, but usually 5 or 10 times larger or even larger than the cross section of the throttle passage.

Particularly preferred embodiments are defined in the further claims.

Fig. 1:

einen Längsschnitt eines Brennstoffeinspritzventils gemäss der vorliegenden Erfindung;

Fig. 2:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt des erfindungsgemässen Brennstoffeinspritzventils von Fig. 1 mit dessen Steuervorrichtung zur Steuerung der Öffnungs- und raschen Schliessbewegung des Einspritzventilgliedes;

Fig. 3:

ein Diagramm mit den Verläufen der Bewegungen des Aktuatorventilgliedes und des Einspritzventilgliedes des Brennstoffeinspritzventils während eines Einspritzvorgangs mit stufenförmiger Öffnungsbewegung des Einspritzventilgliedes;

Fig. 4:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer ersten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils von Fig. 1;

Fig. 5:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer zweiten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils von Fig. 1;

Fig. 6:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer dritten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils der vorliegenden Erfindung;

Fig. 7:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer vierten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils der vorliegenden Erfindung;

Fig. 8:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer fünften alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils der vorliegenden Erfindung;

Fig. 9:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer sechsten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils der vorliegenden Erfindung;

Fig. 10:

im Längsschnitt und in vergrösserter Darstellung einen partiellen Schnitt einer siebten alternativen Konstruktionsvariante der Steuervorrichtung des Brennstoffeinspritzventils der vorliegenden Erfindung;

Fig. 11:

in gleicher Darstellung wir Fig. 8 eine alternative Ausführungsform zur dort gezeigten Variante;

Fig. 12:

in perspektivischer Draufsicht einen Zwischenkörper der Ausführungsform gemäss Fig. 11; und

Fig. 13:

in perspektivischer Untersicht den Zwischenkörper.

The above and other advantages of the present invention will become more apparent from the preferred embodiments which are illustrated in the drawings and described below. It shows purely schematically:

Fig. 1:

a longitudinal section of a fuel injection valve according to the present invention;

Fig. 2:

in a longitudinal section and in an enlarged view a partial section of the inventive fuel injection valve of Fig. 1 with its control device for controlling the opening and rapid closing movement of the injection valve member;

3:

a diagram with the progressions of the movements of the Aktuatorventilgliedes and the injection valve member of the fuel injection valve during an injection process with a stepped opening movement of the injection valve member;

4:

in a longitudinal section and in an enlarged view a partial section of a first alternative design variant of the control device of the fuel injection valve of Fig. 1 ;

Fig. 5:

in a longitudinal section and in an enlarged view of a partial section of a second alternative design variant of the control device of the fuel injection valve of Fig. 1 ;

Fig. 6:

a longitudinal section and in enlarged view a partial section of a third alternative design variant of the control device of the fuel injection valve of the present invention;

Fig. 7:

in longitudinal section and in enlarged scale a partial section of a fourth alternative design variant of the control device of the fuel injection valve of the present invention;

Fig. 8:

in longitudinal section and in enlarged scale a partial section of a fifth alternative design variant of the control device of the fuel injection valve of the present invention;

Fig. 9:

in a longitudinal section and in an enlarged view a partial section of a sixth alternative design variant of the control device of the fuel injection valve of the present invention;

Fig. 10:

in longitudinal section and in enlarged scale a partial section of a seventh alternative design variant of the control device of the fuel injection valve of the present invention;

Fig. 11:

in the same representation we Fig. 8 an alternative embodiment to the variant shown there;

Fig. 12:

in perspective plan view an intermediate body of the embodiment according to Fig. 11 ; and

Fig. 13:

in perspective bottom view the intermediate body.

FIG. 1 shows a fuel injection valve 1, which is intended for the intermittent injection of fuel into the combustion chamber of an internal combustion engine. It has an elongate, circular cylindrical and stepped housing 6, the housing axis is denoted by 8. The housing 6 consists of a housing body 10, a first intermediate plate 12, a second intermediate plate 14 and a nozzle body 16. The first intermediate plate 12 and the second intermediate plate 14 form an intermediate part 17. The intermediate plates 12 and 14 and the nozzle body 16 are provided with a Union nut formed clamping nut 18 in a tight manner against each other and clamped together against a lower surface 10 a of the housing body 10. The first intermediate plate 12 rests against the nozzle body 16 and the second intermediate plate 14 on the housing body 10.

A designed as a high-pressure supply hole high-pressure fuel inlet 20 of the fuel injection valve 1 is connected in a known manner with a fuel feed, which the fuel injector 1 fuel at very high pressure, for example, up to 1800 bar or higher, supplies. The high-pressure fuel inlet 20 opens laterally into the housing body 10, but could also be made more or less parallel to the housing axis 8 from above in the housing body 10. In the high-pressure fuel inlet 20 opens a longitudinal bore 22, which is also made in the housing body 10 and the other end opens into the lower surface 10 a of the housing body 10.

The longitudinal bore 22 diametrically opposite and on a Aktuatorachse 8 ', the desachsiert with respect to the Housing axis 8 is, there is an actuator 24, which is preferably designed as a piezoelectric actuator 26 and could alternatively be designed as Elektromagnetaktuator.

In a high pressure chamber 42 of the nozzle body 16 are a needle-shaped injection valve member 28, a support sleeve 30, a washer 32, a compression spring 34 and a guide sleeve 36. About the washer and support sleeve 30, the compression spring 34 is supported on the injection valve member 28.

A bore 38 through the second intermediate plate 14 and a bore 40 through the first intermediate plate 12 connect the longitudinal bore 22 with the high pressure chamber 42. This high pressure chamber 42 extends from the intermediate plates 12, 14 facing end face 16b of the nozzle body 16 to an injection valve seat 44th Downstream of the injection valve seat 44, the nozzle body injection openings 44 'on. The injection valve member 28 has a radial guide 46 with the nozzle body 16, which is interrupted by abutment surfaces 48 of the injection valve member 28 for hydraulically virtually resistant supply of high-pressure fuel to the injection valve seat 44.

In the first and second intermediate plates 12 and 14 is a hydraulic control device 52 for controlling the opening and the rapid closing movements of the injection valve member 28 during the injection process. The control device 52 of the fuel injection valve 1 will be described in detail in connection with FIG FIG. 2 shown and described. A low-pressure fuel return 50 relieves fuel to Control of the movements of the injection valve member and leads this fuel away from the fuel injection valve. 1

In the description of the in the Figures 2 - 8 In the embodiments shown, the same reference numerals are used for the corresponding parts as used in connection with the description of FIG FIG. 1 Further, in the following, only the differences to in the FIG. 1 shown fuel injector 1 or already previously described embodiments set forth.

FIG. 2 shows in longitudinal section and in an enlarged view a part of the inventive fuel injection valve 1 of FIG. 1 with its control device 52 for controlling the opening and rapid closing movement of the injection valve member as presented in the pause time between two injection events.

A control piston 28 'of the injection valve member 28 is radially guided in a close sliding fit in the guide sleeve 36 and axially displaceably mounted. It limits together with the guide sleeve 36, the end face 36b of the spring 34 is pressed against a lower surface 12a of the first intermediate plate 12 sealing and resting in abutment, a control chamber 54. A shaft 58 of a standing on his head 60 mushroom-shaped intermediate valve member 56 engages a, in the axial direction, through opening of the first intermediate plate 12 and is guided at this with a tight sliding fit 58 '. The head 60 of the intermediate valve member 56 is slidable in the axial direction, in a recess 62 of the Guide sleeve 36. The recess 62 is hydraulically permanently connected by means of radial passages 56 "in the head 60 with the control chamber 54 and thus part of the control chamber 54. The head 60 is supported by a small compression spring 66 resting on a lower surface 14a of the second intermediate plate 14 pressed against a shoulder 64 of the guide sleeve 36.

A precise throttle passage 68 of the intermediate valve member 56 permanently connects the control chamber 54 with a valve chamber 70 in the second intermediate plate 14; a recess extending through the second intermediate plate 14 and delimited by the first intermediate plate 12 and the housing body 10 forms the valve space 70. The valve space 70 is hydraulically connected via a passage 70 'to the back of the intermediate valve member 56; the small space in the through opening of the first intermediate plate 12 on the back of the intermediate valve member 56 thus forms a hydraulic part of the valve chamber 70. The throttle passage 68 is located according to Fig. 2 directly adjacent to the control chamber 54, could alternatively be sunk along the axially extending through the intermediate valve member 56, hydraulic connection bore or at the other end of this communication bore in the shaft 58, which has no effect on the function of the fuel injection valve 1.

In the valve chamber 70 there is actuated by the piezo actuator 26 Aktuatorventilglied 72, which bears in its closed position, with its conical sealing surface, sealingly formed on a housing body 10, annular valve seat DS. The valve seat DS is formed by the mouth of a housing body 10 in the housing Outlet passage 73 formed; this exhaust passage 73 leads to the low pressure fuel return 50. An actuator valve member spring 74 exerts a constant but small spring force in the direction of the valve seat DS toward the actuator valve member 72, as compared to the fuel pressure force.

A bore 76 of relatively large cross section in the first intermediate plate 12 connects the control chamber 54, via a lateral passage in the second intermediate plate 14, with the bore 38. When the intermediate valve 56 'is closed, this connection is interrupted, in its open position, the intermediate valve 56 The lateral passage may alternatively be made in the first intermediate plate 12.

The dimensions of the above-mentioned outlet passage, the bore orifice of the throttle passage are, for example, 0.20 mm for the throttle passage 68, 0.80 mm for the bore 76 and 1.3 mm for the valve seat DS of the Aktuatorventilgliedes 72 at a full opening stroke of the Aktuatorventilgliedes 72 of about 0.025 mm. The latter corresponds to an outlet throttle passage 73 corresponding to a bore of approximately 0.36 mm diameter, all of which are indicative only. The above data show that the sole essential control cross section, which is decisive for the opening movement of the injection valve member 28 when the actuator valve member 72 is open, is represented by the throttle passage 68.

The operation of the fuel injection valve 1 is as follows: the piezoelectric actuator 26 is energized, this expands and opens by means of movement of the Actuator valve member 72 down the valve seat DS and thus the outlet passage 73. This position of the Aktuatorventilgliedes 72 is in Fig. 2 shown with dashed line. The fuel pressure in the valve chamber 70 drops rapidly. Thereby, the mushroom-shaped intermediate valve member 56 is moved away from its abutment on the shoulder 64 in the upward direction. Since the intermediate valve 56 'is still open, fuel from the bore 76 flows into the control chamber 54 until the intermediate valve 56 is closed, which happens when the flat top of the head 60 abuts the lower surface 12a. At this time, the pressure in the control chamber 54 has dropped little. Also, because of the tight sliding fit 58 ', which causes a, except for a small and for the separation function insignificant leakage, constantly existing hydraulic separation between the control chamber 54 and the valve chamber 70, only very little fuel in the valve chamber 70 reach where the pressure already dropped sharply at this time. Now - with the intermediate valve 56 closed - the pressure in the control chamber 54, because of fuel discharge through the throttle passage 68, drop more. This causes the injector member 28 to move away from the injector seat 44, allowing fuel to flow under high pressure from the high pressure chamber 42 to the injector ports 44 'via the injector seat 44 and begin the injection process. When the piezoactuator 26 is completely de-energized, the actuator valve member 72 closes the outlet passage 73 by moving it upwardly. As a result, a rapid pressure equalization takes place between the control chamber 54 and the valve chamber 70, which causes the intermediate valve member 56 of the system pressure in a, connected to the bore 76, around the shaft 58th around-running and towards the head 60 open groove 76 'and in a small proportion by the force of the spring 66 moves down again and the intermediate valve seat 56' opens again. The injection valve member 28 is now moved rapidly in the direction of the injection valve seat 44 until the injection process is interrupted. For the realization of separate pre- or post-injections with a main injection between them and with very short time intervals between the individual injections, the intermediate valve member 56 can be moved by re-energizing the Piezoaktuators 26 during the closing movement of the injection valve member 28 again in the closing direction of the intermediate valve 56 'because the control chamber 54 and the distribution chamber 70, due to the sliding mount 58, are hydraulically practically separated. The subsequent injection may be immediately adjacent to the end of the previous one, and the distance between the individual separate injections may be virtually reduced to zero.

Since the switchable cross-section of the intermediate valve 56 'is substantially larger than that of the throttle passage 68, this inventive control device 52 for controlling both small fuel injectors 1, such as for applications in passenger or truck engines, as well as much larger fuel injection valves, for example in locomotives, earthmoving machinery, power plants and ships.

FIG. 3 shows the course of the movement of the injection valve member 28 in the event that the Aktuatorventilglied 72 during periods of not separate, but graduated injection operation, occupying a position between its maximum open and its closed position. The timing of this actuator valve member stroke, labeled "AH", is in the upper diagram of FIG Fig. 3 represented as AH (t) so that movement of the Aktuatorventilgliedes in the downward direction (as shown by Fig. 2 ) opens or further opens the outlet passage 73. The temporal Einspritzventilgliedhubverlauf is referred to as EH (t). The scales of AH and EH are different because, as already mentioned, the full opening stroke of the Aktuatorventilgliedes 72 is of the order of 0.025 mm and the full opening stroke EH of the injection valve member, depending on the engine size of a specific application, between 0.20 mm to about 1.0 mm is.

At time t1, the piezoactuator 26 is energized and the actuator valve member 72 opens, so that the opening movement of the injection valve member 28 begins at t2. Between t2 and t3, the injection valve member 28 opens quickly but only travels a short distance, as the energization of the piezo actuator 26 is withdrawn and thus the actuator valve member 72 reduces the opening stroke to such an extent that the remaining outlet passage cross-section also acts as a throttle. As a result, the opening speed of the injection valve member is kept greatly reduced until the piezoelectric actuator is fully energized again and the full speed of the opening stroke is restored, which is the case at t4. The injection valve member 28 then opens again quickly up to t5 and its opening is controlled by the throttle passage 68. It is thus possible to realize a stepped injection course.

The course shown of EH (t) after the time t5 arises when the injection valve member 28 has no mechanical stroke stop or even during a Volllasteinspritzvorgangs reached no mechanical stroke stop. This is thus an alternative possibility, which works without a mechanical stroke stop. It is possible by further reduction of Aktuatorventilgliedhubes, analogously as between t3 and t4, the opening speed of the injection valve member 28, starting from the present at t5 stroke EH, which corresponds to a full opening stroke of a fuel injection valve with mechanical stroke stop to reduce again. This makes it possible to keep the maximum value of the stroke EH before the beginning of the closing process of the injection valve member 28 even within limits when the injection process takes a long time. This condition occurs especially with fuel injection valves for large diesel engines.

At time t6, the actuator valve member 72 is in the closed position. Thus, between the time t6 and t7, the injection valve member 28 closes and the stroke EH (t) rapidly approaches zero. If the piezoactuator 26 is briefly energized again before the injection valve member 28 reaches the injection valve seat 44, its impact velocity on the injection valve seat 44 can be reduced to such an extent that a low seat load and, if this is a critical condition, a longer service life of the injection valve seat 44 can be achieved , The courses of AH (t) and EH (t) · for this case are shown in dashed lines.

FIG. 4 shows in longitudinal section and in enlarged view a partial section of a first alternative design variant of the control device 52 'of the fuel injection valve 1. The mushroom-shaped intermediate valve member 56 is completely recessed in the first intermediate plate 12 and forms, together with the first intermediate plate 12, an intermediate valve 56' with a conical seat. The remote from the end face 36b of the guide sleeve 36 shoulder 64 of Fig. 2 eliminated. The guide sleeve 78 of Fig. 4 has a flat end surface 78b, which both together with the lower surface 12a of the first intermediate plate 12, the control chamber 54 seals radially against the high-pressure chamber 42 and forms the stop for the head 60 of the intermediate valve member 56. The bore 76 opens directly into the bore 40. Thus, the intermediate valve member 56 and the first intermediate plate 12 form a structural unit with a coordinated stroke of the intermediate valve member 56. Alternatively, these, the intermediate part 17 forming two intermediate plates 12 and 14 could also consist of a single workpiece, which in the Fig. 1 and 2 could also be realized.

In addition, the embodiment according to Fig. 4 a piston member 80 on. This arrangement could also be in the variant of Fig. 2 be used. On the other hand, the variant of Fig. 4 be realized without this piston element 80. The piston element 80 is guided with a relatively narrow sliding fit 80 'in a blind hole-like recess in the first intermediate plate 12. A small compression spring 82 constantly pushes the piston member 80 to the underside of the Aktuatorventilgliedes 72 at. A space 84 in which the compression spring 82 is located and which is delimited by the underside of the piston element 80, is continuously hydraulically connected by means of a passage 86 with the recess 62 and the passages 56 "in the head 60 of the intermediate valve member 56 with the control chamber 54.

The operation of the arrangement of the intermediate valve member 56 with conical valve seat is analogous to that of FIG. 2 , The function of the piston element 80 is as follows: If the actuator valve member 72 is pressed down by the piezoactuator 26, the piston element 80 makes this movement. As a result, the piston member 80 increases the volume of the valve chamber 70 and at the same time reduces by its pumping action the volume of the space 84. Both cause a faster closure of the intermediate valve 56 ', since the intermediate valve member 56 is caused to move upwards more rapidly. Conversely, when the actuator valve member 72 moves upwardly, the piston member 80 causes an increase in the volume of the space 84 and at the same time a pumping action in the valve chamber 70. This causes a faster response of the intermediate valve member 56 when opening the intermediate valve 56 '. The piston member 80 thus supports a particularly rapid response of the intermediate valve member 56th

FIG. 5 shows in longitudinal section and in an enlarged view a partial section of a second alternative design variant of the control device 52 "of the fuel injection valve of FIG. 1 , The second intermediate plate 106 has no valve space, but only an outlet passage 110, which via a Passage 108 in the first intermediate plate 104, which the intermediate part 17 forming intermediate plates 104 and 106, in turn, could be realized as a single workpiece, is hydraulically connected to the back of the shaft 58 of the intermediate valve member 56. Alternatively, the passage 108 could also be made in the second intermediate plate 106. The valve space 70 of Fig. 5 is of particularly small volume content. The cross section of the outlet passage 110 may be substantially larger than the cross section of the throttle passage 68. The actuator shaft 112 is locked in the in FIG. 5 shown position the outlet side of the outlet passage 110 so that no injection can take place. When the actuator shaft 112 is moved upwardly, the fuel pressure in the exhaust passage 110 and the passage 108 rapidly drops, causing the fuel injection valve to move in a manner analogous to that described in US Pat Fig. 1 and 2 described, can inject. When the actuator shaft 112 is moved toward the outlet side of the exhaust passage 110 again and closed, the injection is terminated. The actuator for the actuator shaft 112 may be either a piezo actuator or an electromagnetic actuator, which attracts the actuator shaft 112 in a known manner when energized.

FIG. 6 shows in longitudinal section and in an enlarged view a partial section of a third alternative design variant of the control device 52 '"of the fuel injection valve 1. The two intermediate plates 104 and 106 of the embodiment according to Fig. 5 are replaced by a single intermediate plate 105; it forms the intermediate part 17. An outlet element 109 is located, coaxial with the desachsierten axis 8 ', in a recess of the intermediate plate 105 and is pressed by a plate spring 107 and the fuel pressure in the valve chamber 70 to the lower surface 10 a of the housing body 10, or alternatively a support member unspecified, sealing in abutment. The outlet passage 110 is located in the outlet element 109. The advantages of this variant are the use of a single intermediate plate 105 instead of two intermediate plates 104 and 106 and the fact that the outlet element 109, which is of small dimensions, is of a very wear-resistant and also expensive Material can be produced inexpensively.

Dashed line will appear in Fig. 6 an alternative shown in which a throttle passage 77 connects the bore 40 with the small valve chamber 70. This causes a very rapid opening of the intermediate valve member 56 as soon as the outlet side of the outlet passage 110 is closed.

FIG. 7 shows in longitudinal section and in an enlarged view a partial section of a fourth alternative design variant of the control device 88 of the fuel injection valve, in which the mushroom-shaped intermediate valve member 56 analogous to the FIGS. 4 . 5 or 6 is trained. The control device 88 is located in a high-pressure chamber 90, which has the same function as the high-pressure chamber 42 and is manufactured in a body 92 surrounding the high-pressure chamber 90. The body 92 could be a nozzle body 16 or a housing body 10 or also an intermediate plate, analogous or similar as in FIGS FIGS. 1 . 2 . 4 . 5 and 6 shown. In the high-pressure chamber 90 of the control piston 28 'of the injection valve member 28 projects and the compression spring 34 presses the flat surface 78b of the guide sleeve 78 in tight engagement with a lower end surface 94a of an intermediate element 94, in which the mushroom-shaped intermediate valve member 56 is guided in a close sliding fit 94 '. A bore 96 in the intermediate member 94 connects the recess 62 in which the intermediate valve member 56 is located, and a groove 96 'around the shaft 58 of the intermediate valve member 56 with a passage 98 and thus the high-pressure chamber 90. The intermediate member 94 is in place of the first intermediate plate 12 of the FIGS. 1 . 2 . 4 and 5 provided and is guided by a radially inner wall 100 of the body 92 with play on the circumference and axially aligned with the longitudinal axis 102. The outlet passage 110 is located in a disc-shaped outlet member 114, which is positioned radially analogously to the intermediate member 94 of the wall 100 with clearance. The upper side 114b of the outlet element 114 and the lower side 116a of a closing element 116, similar to the housing body 10, close off the high-pressure chamber 90 in a known manner in a pressure-tight manner. The intermediate member 94 and the outlet member 114 form the intermediate part 17. Also in the embodiment according to Fig. 7 is like that according to Fig. 5 , the volume content of the valve space 70 is very small. Same as in the embodiments according to Fig. 5 or 6 can by means of actuation of the actuator shaft 112, the end face of the shaft 58 of the intermediate valve member 56 for the realization of intermittent diesel injections druckent- and be charged. The solution of Fig. 7 is advantageous if the control device 88 is installed to save space in a bore on the axis 102 of the fuel injection valve and is dispensed with the intermediate plates 12, 14, 104, 105 and 106 of the preceding figures.

Alternatively, the intermediate member 94 and the outlet member 114 could be made together in one piece. Analogous to Fig. 6 Alternatively, the throttle passage 77 connects the high-pressure chamber 90 with the valve chamber 70, which is shown in dashed lines and has the same effect as in Fig. 6 ,

Furthermore, the construction of FIG. 7 a mechanical stroke stop 79 for the end face of the control piston 28 'of the injection valve member 28 in the form of an integral with the guide sleeve 78 and projecting wall which projects into the control chamber 54 and is provided with a central passage 79 b, which the control chamber 54 with the recess 62nd connects hydraulically. This or an embodiment corresponding in its function could also be used in the embodiments according to the other figures. Conversely, the in Fig. 7 embodiment shown also be executed without mechanical stroke stop 79.

In an alternative variant, not shown, the solutions of Fig. 5 and Fig. 7 be combined in such a way that all elements of Fig. 7 except the disc-shaped outlet member 114 are located in the high pressure space 90 on the longitudinal axis 102, but the outlet passage 110 is in one, the second intermediate plate 106 of Fig. 5 similar intermediate plate on the desachsierten actuator axis 8 'is located. A passage 108 of Fig. 5 equivalent passage must then run in this intermediate plate so that it does not establish a hydraulic connection to the high-pressure chamber 90 on its course from the end face of the shaft 58 of the intermediate valve member 56 to the outlet passage 110. This is the case when the passage is for example as oblique hole is performed in this intermediate plate. The intermediate plate will then be thicker than in Fig. 5 shown in order to accommodate the oblique inside passage of the passage can.

FIG. 8 shows in longitudinal section and in an enlarged view a partial section of a fifth alternative design variant of the control device 88 of the fuel injection valve, that of Fig. 7 is similar. The mushroom-shaped intermediate valve member 56 has as in Fig. 2 shown a flat seat. However, there is no groove 76 'in the intermediate element 94 available. Two opposing holes 96 in the intermediate member 94 (it could also be a bore 96 or more than two holes 96) form with its open inlet into the recess 62 together with the intermediate valve member 56, the intermediate valve 56 '. When the intermediate valve member 56, for allowing intermittent injections, closes the bores 96, this construction, in addition to the passage in the recess 62, also closes the passage to the sliding fit 94 "of the stem 58 with the intermediate member 94. This sliding fit 94" is now allowed, if desired, may be made less accurate than those of the previous design variants, and their play may be, instead of typically 2 to 6 micrometers, a close sliding fit as in the embodiments of FIGS Fig. 1 to 7 , up to 50 microns. With a clearance of 50 microns in the injection process, the leakage from the groove 76 '( Fig. 2 ) or the corresponding position of the preceding figures in the valve chamber 70 very large, which with the variant of Fig. 8 does not occur, because in addition to the closing of the holes 96, by means of the intermediate valve 56 ', and the sliding fit 94 "from the high-pressure chamber 90th is separated. However, even with this variant, the sliding fit 94 "must bring about at least one hydraulic separation point which produces a sufficient pressure difference so that the intermediate valve member 56 very quickly closes the bores 96 after actuation of the actuator arrangement 24. Otherwise, the outlet of the bores 96 can enter the recess 62 may be widened circumferentially around the axis 102 to obtain a larger small stroke flow area of the intermediate valve member 56. A kidney-shaped extension or groove extending circumferentially of the recess 62 and sliding fit 94 "and from a flat seat is then obtained is surrounded. Furthermore, the control device 88 of FIG. 8 unlike those of the preceding figures, no compression spring 66, which may also be realized in the previous embodiments. The intermediate valve member 56 is then controlled solely by hydraulic forces.

With 94b an alternative separation point between the guide sleeve 78 and the intermediate element 94 is sketched with a dashed line. Alternatively, the intermediate member 94 and the outlet member 114 could be made in one piece.

FIG. 9 shows in longitudinal section and in enlarged view a partial section of a sixth alternative design variant of a control device 140 of the fuel injection valve of the present invention.

In the second intermediate plate 14 is a acting as a 2/3 way valve, pill-like flat seat valve member 120 which of a valve pin 122, for example can be actuated by a piezo actuator, can be moved. The flat seated valve member 120 may perform a specific small stroke in the second intermediate plate 14, between the housing body 10 and the first intermediate plate 12. In a preferred embodiment, the flat seat valve member 120 has two flat seats, because it is thus particularly easy to obtain the particular small stroke by the difference in the thickness of the second intermediate plate 14 and the thickness of the flat seat valve member 120. In the de-energized state of the piezo actuator 26, the flat seat valve member with a first valve seat 124 closes the connection between the valve chamber 70 and the low-pressure fuel return 50 (see Fig. 1 ) and at the same time releases a high-pressure channel 126, which is located in the first intermediate plate 12 and is connected to the high-pressure chamber 42, from a relatively large, unthrottled cross-section. The passage cross section between the flat seat valve member 120 and the first intermediate plate 12, ie the second valve seat 128, in the shown position of the flat seat valve member 120, releases a substantially larger cross section with respect to the throttle passage 68 of an intermediate plate 132 forming a check valve 130. This can be achieved by the high-pressure passage 126 itself defining a sufficiently large circumferential seat cross-section with the valve seat 128, but an extension of the high-pressure passage 126 could also be formed in the region of the valve seat 128, of whatever geometric shape, to create a lateral surface on the valve seat 128, which is substantially larger than the passage of the throttle passage 68.

The lateral passage 70 'and a central passage bore 138 in the first intermediate plate 12 of relatively large cross-section connect the valve space 70 to the throttle passage 68 in the intermediate plate 132, which has lateral recesses 136 and pressed by a compression spring 134 to the lower surface 12 a of the first intermediate plate 12 becomes. During the opening movement of the injection valve member 28, the position of the intermediate pad 132 is as in FIG Fig. 9 shown. As shown in dashed lines, the passage bore 138 could also be arranged obliquely, so that the passage 70 'can be omitted.

The function of the control device 140 is as follows: for injection, the actuator assembly pushes the flat seat valve member 120 from its abutment position on the first valve seat 124 to the upper surface 12b of the first intermediate plate 12 by means of the valve pin 122, thus opening the first valve seat 124 to the low pressure outlet 50 and closing it As a result, the pressure in the valve chamber 70 drops and consequently also in the control chamber 54. The injection valve member 28 can open and the opening movement is controlled by the throttle passage 68. If the first valve seat 124 is closed by the movement of the flat seat valve member 120 to terminate the injection, the second valve seat 128 opens at the same time. The fuel flow through the relatively large cross sections into the valve chamber 70 and into the passage bore 138 opens the intermediate plate by removing it from its installation is pushed away on the lower surface 12 a. Through the recesses 132 of the fuel flow enters the control chamber 54 and the injection process is completed quickly. By multiple actuation of the actuator assembly Thus, multiple injections can be realized with a very short time interval. Alternatively, the intermediate plates 12 and 14 can be integrally realized from a workpiece.

FIG. 10 shows in longitudinal section and in enlarged view a partial section of a seventh alternative design variant of the control device 142 of the fuel injection valve of the present invention, which is similar to the execution of Fig. 9 is.

The exact throttle passage 68 is located in the flat seat valve member 144 and communicates via the passage bore 146 of relatively large cross-section with the control chamber 54. In order to bridge the desachsing of the two longitudinal axes 8 and 8 ', it is advantageous if the passage bore 146 in the first intermediate plate 12, as shown, is arranged obliquely. As in Fig. 10 is shown, the throttle passage 68 must be aligned with the passage hole 146. This is ensured when the flat seat valve member 144 is not circular, but for example, has two chamfered surfaces laterally or oval or (right) is angularly aligned with an associated guide shape of the valve chamber 70 of the second intermediate plate 14 on the circumference. Alternatively, a groove 146b in the first intermediate plate 12 (shown in phantom) or in the flat seat valve member 144 could ensure the hydraulic connection with a circular shape of the flat seat valve member 144. Since the passage bore 146 and also any distance in the groove 146b are short, the effect of the changed position of the throttle passage 68 is functionally the same as if the throttle passage 68 would be geometrically connected directly to the control chamber.

Again, the intermediate plates 12 and 14 could be combined to form a workpiece.

The function of the control device 142 is analogous to that of Fig. 9 , The construction is easier because in FIG. 10 the intermediate plate 132 and the compression spring 134 are not needed.

At the in Fig. 11 shown embodiment of the fuel injection valve according to the invention, the intermediate element 94 and the outlet 114 of the in Fig. 8 shown embodiment to a single workpiece, an intermediate body 150, summarized. The intermediate part 17 forming the disc-like intermediate body 150 is held by means of the clamping nut 18 sealingly on the one hand on the nozzle body 16 and on the other hand on the housing body 10 in abutment. The Fig. 12 and 13 show the intermediate body 150 enlarged.

A downwardly open, blind hole-like recess in the intermediate body 150 forms with its circular cylindrical shell the sliding fit 58 'with the shaft 58 of the mushroom-like intermediate valve member 56 and limited with the shaft 58, the valve chamber 70. This is on the one hand via a very narrow Zulassbohrung 152 with, with The longitudinal bore 22 connected to the high-pressure inlet and, on the other hand, to the control chamber 54 via the precise throttle passage 68 in the intermediate valve member 56. Further, from the valve space 70, with respect to the longitudinal axis 102, the outlet passage 110 leads to the passage in the housing body 10, in which the actuator shaft 112 is arranged and which opens into the low-pressure return 50.

In the radial direction outside the central, blind hole-like recess extend through the intermediate body 150 through three holes 96, which are on the overhead side by a substantially V-shaped connecting groove 154 with the longitudinal bore 22 interference connected. On the lower side they open into the control chamber 54 and are closed by means of the head of the intermediate valve member 56.

Starting from the V-shaped connecting groove 154 extends through the intermediate body 150 in the axial direction of the bore 40, which opens on the underlying side in a U-shaped distribution groove 156 in the intermediate valve body 150. This provides, radially outside the guide sleeve 78, the connection to the high-pressure chamber 90 safe. By the compression spring 34, the guide sleeve 78 is held with its end face 78b on the intermediate body 150 in close contact with the guide sleeve 78 between the U-shaped distribution groove 156 and the mouth of the holes 96 abuts the intermediate body 150. In its this side end region, the guide sleeve 78, compared with the region of the close sliding fit with the control piston 28 'of the injection valve member 28, extended formed to accommodate the head of the intermediate valve member 56 with sufficient radial play.

Furthermore, the intermediate body 150 has two blind-hole-like positioning holes 158 into which positioning pins on the housing body 10 engage.

How this particular out Fig. 12 can be seen, may be hardened around the mouth of the outlet passage 110 extending, cooperating with the flat end face of the Aktuatorschafts 112, a valve seat forming annular region.

With dashed lines is in Fig. 11 in an analogous manner as described above, a variant shown where the intermediate body 150 consists of two parts which are separated from each other.

In the idle state, the actuator shaft 112 closes the outlet passage 110, the injection valve member 28 abuts the injection valve seat 44, and the intermediate valve 56 'is opened; his head abuts an inner shoulder of the guide sleeve 78. To initiate an injection process, the actuator shaft 112 is withdrawn, resulting in a pressure drop in the valve chamber 70, because the flow cross section of the outlet passage 110 is substantially greater than the sum of the flow cross sections of the throttle passage 68 and the inlet bore 152. This has the consequence that the intermediate valve 56th 'closes and the pressure in the control room 54 therefore falls very quickly. The injection valve member 28 is lifted by the pressure drop in the control chamber 54 against the action of the compression spring 34 from the injection valve seat 44. To end the injection process, the outlet passage 110 is closed by means of the actuator shaft 112. It comes very quickly to an at least approximate pressure equalization between the control chamber 54 and the valve chamber 70. Next practicing the outstanding in the holes 96 high pressure and, via the control piston 98 ', the compression spring 34 an opening force on the intermediate valve member 56, which is a very fast Closing movement of the injection valve member 28 causes. As described above, multiple injections are possible.

The in the Fig. 11 displayed embodiment also works without Zulassbohrung 152. Feeding the opening of the intermediate valve 56 'slightly delayed.

In the embodiments shown, the opening cross section of the outlet passage is at least twice as large as the cross section of the exact throttle passage 68.

Of course, the features of the control devices of the fuel injectors of the present invention may also be used individually or in combinations other than those shown herein, as defined in the appended claims.

Claims (16)

1. A fuel injection valve (1) for the intermittent injection of fuel into the combustion space of an internal combustion engine, with a housing (6) which has a housing body (10) and a nozzle body (16) with an injection valve seat (44), with a high-pressure space (42; 90) which is arranged in the housing (6) and which is connected to a high-pressure fuel inlet (20) and to the injection valve seat (44), with an injection valve member (28) which is arranged longitudinally adjustably in the housing (6) and which cooperates with the injection valve seat (44), with a compression spring (34) which is supported, on the one hand, on the injection valve member (28) and acts upon the latter with a closing force directed toward the injection valve seat (44) and which is supported, on the other hand, on a guide sleeve (36; 78) and at the same time presses the guide sleeve (36; 78) sealingly against an intermediate part (17), the guide sleeve (36; 78), together with a control piston (28') guided in the guide sleeve (36; 78) of the injection valve member (28), delimiting a control space (54) with respect to the high-pressure space (42; 90), and with a control device (52; 52'; 52"; 52"', 88) for controlling the axial movement of the injection valve member (28) by varying the pressure in the control space (54), with an intermediate valve (56'), the intermediate valve member (56) of which, in the open position, releases a high-pressure admission (76, 96) into the control space (54) and, in the closing position, cuts off the high-pressure admission (76, 96) and also separates the control space (54) from a valve space (70) - with the exception of a throttle passage (68) -, and an electrically actuated actuator arrangement (24) for connecting the valve space (70) to and for separating the valve space (70) from a low-pressure fuel return (50), characterized in that the intermediate valve member (56) separates the control space (54) permanently from the valve space (70) - with the exception of the throttle passage (68).
2. The fuel injection valve as claimed in claim 1, characterized in that the high-pressure admission (76, 96) is formed by a passage leading into the control space (54) and having a large cross section, as compared with the cross section of the throttle passage (68).
3. The fuel injection valve as claimed in claim 1 or 2, characterized in that the intermediate valve member (56) is of mushroom-shaped design, with its head (60) controls the high-pressure admission (76, 96) and is guided with its shank (58) with a sliding fit (58'; 94'; 94") in the intermediate part (17) and thus delimits the valve space (70).
4. The fuel injection valve as claimed in claim 3, characterized in that the sliding fit (58'; 94') is a close sliding fit.
5. The fuel injection valve as claimed in one of claims 1 to 4, characterized in that, in the open position, the intermediate valve (56') has a substantially larger cross section than the cross section of the throttle passage (68).
6. The fuel injection valve as claimed in one of claims 1 to 5, characterized in that a flat seat cooperating with the intermediate valve member (56) is formed on the intermediate part (17).
7. The fuel injection valve as claimed in one of claims 1 to 5, characterized in that a conical seat cooperating with the intermediate valve member (56) is formed on the intermediate part (17).
8. The fuel injection valve as claimed in claim 3 or 4, characterized in that, in the closing position, the intermediate valve (56') prevents the passage of fuel from the high-pressure admission (76, 96) to the sliding fit (58', 94', 94").
9. The fuel injection valve as claimed in one of claims 1 to 8, characterized in that the intermediate valve member (56) is constantly acted upon by the force of a compression spring (66) in the direction of the open position.
10. The fuel injection valve as claimed in one of claims 1 to 9, characterized in that the actuator arrangement (24) has an actuator valve member (72) which, to open the outlet passage (73), is moved into the valve space (70) and, by means of its movement, co-moves a piston element (80) which reduces the volume of the control space (54) and which is moved in the opposite direction in order to close the outlet passage (73), the piston element (80) reducing the volume of the valve space (70) by bearing constantly against the actuator valve member (72).
11. The fuel injection valve as claimed in one claims 1 to 10, characterized in that an outlet passage (110) leads away from the valve space (70) and is preferably formed in a separate outlet element (109; 114).
12. The fuel injection valve as claimed in claim 11, characterized in that the outlet passage (110), the intermediate valve member (56), the guide sleeve (78) and the injection valve member (28) are arranged on a longitudinal axis (102) of the fuel injection valve.
13. The fuel injection valve as claimed in one of claims 1 to 12, characterized in that the intermediate part (17) has a nozzle body-side first intermediate plate (12) and a housing body-side second intermediate plate (14) bearing over a large area against said first intermediate plate (12), and the valve space (70) is delimited circumferentially by the second intermediate plate (14; 106) and on the end face by the housing body (10) and the first intermediate plate (12; 104).
14. The fuel injection valve as claimed in claims 3 and 13, characterized in the sliding fit (58') is formed in the first intermediate plate (12; 104).
15. The fuel injection valve as claimed in one of claims 1 to 14, characterized in that the actuator arrangement (24) is arranged on an actuator axis (8') axially offset with respect to a longitudinal axis (8).
16. The fuel injection valve as claimed in one of claims 1 to 15, characterized in that the actuator arrangement (24) controls the fuel flow into the low-pressure fuel return (50) as a function of the stroke, and the opening movement of the injection valve member (28) takes place more slowly in the case of part stroke than in the case of the maximum stroke.

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