WO2010088781A1

WO2010088781A1 - Fuel injection valve for internal combustion engines

Info

Publication number: WO2010088781A1
Application number: PCT/CH2010/000016
Authority: WO
Inventors: Marco Ganser
Original assignee: Ganser-Hydromag Ag
Priority date: 2009-02-09
Filing date: 2010-01-22
Publication date: 2010-08-12
Also published as: EP2394049B1; EP2394049A1; CH700396A1

Abstract

The control apparatus (88) of a fuel injection valve comprises a mushroom-shaped intermediate valve member (56), which is guided in an intermediate element (94) with a sliding fit (94''). Together with a guide sleeve (78) and the lower surface of the intermediate element (94), the injection valve member (28), which has a control plunger (28'), for opening and closing injection openings so as to implement intermittent injection processes defines a control space (54). An outlet element (114) is located between the intermediate element (94) and the housing body (116) and delimits a valve space (70), which is hydraulically connected to the face of the stem (58) of the mushroom-shaped intermediate valve member (56). The intermediate valve member comprises a stem (58), which is guided in the intermediate element (94) with a sliding fit, and a head (60), which rests with the sealing surface (61) thereof at least partially against a surface (57) of an intermediate valve seat (59) configured on the intermediate element (94) in the closed position of the intermediate valve member (56) in order to separate the high pressure inlet (96) from the control space (54), wherein the sealing surface (61) of the head (60) and the surface (57) of the intermediate valve seat (59) are designed such that they create a throttled fluid connection between the high pressure inlet (96) and the sliding fit in the closed position of the intermediate valve (56').

Description

FUEL INJECTION VALVE FOR COMBUSTION MACHINES

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 known, for example, from WO 2007/098621 A1 of the Applicant. Such fuel injectors have a simple structure 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. In this case, the realization of multiple injections with very short time intervals is possible in such a fuel injection valve. While the control chamber and the valve chamber are permanently connected to one another via an exact throttle passage, the intermediate valve, moreover, permanently separates these two chambers from one another. The throttle passage is disposed immediately adjacent to the control room. The connected to the high-pressure chamber of the injection valve, leading into the control chamber high-pressure admitting large cross section, 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 arrangement 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 in - 9 -

essentially alone from the cross section of

Throttle passage dependent. When closing the spout from the valve chamber by means of the actuator assembly, the intermediate valve opens quickly and gives the connected to the high-pressure chamber passage of large

Cross section free, causing a rapid termination of the injection process.

The embodiment variants of the fuel injection valve shown in WO 2007/098621 in the local FIGS. 1 to 7 show the receptacle of the shaft of the intermediate valve member in a close sliding fit, which is formed in the intermediate part. A close sliding fit is absolutely necessary in order to provide sufficient separation between the high-pressure admission valve and the valve space open to the low-pressure fuel outlet, even in the open position of the intermediate valve, except for negligible leakage for the function of the injection valve. This tight sliding fit requires very precisely manufactured components, in particular the shaft of the intermediate valve member and the bore receiving the shaft must be made in the intermediate part with very small tolerances in the range of a few micrometers, whereby the production of these components of the fuel injection valve is expensive.

A sliding fit with a tolerance of up to several hundredths of a millimeter between the shank of the intermediate valve member and the bore in the intermediate part can be achieved according to the alternative embodiment in FIG. 8 of WO 2007/098621 if the high-pressure admission in the closed position of the intermediate valve through the sealing surface of the head the intermediate valve member is closed and thus the flow of Hσchdruckzulass to the valve chamber is completely interrupted. In this case, the sealing surface of the head lies flat against the surface of the intermediate valve seat.

However, it has been shown that the complete closure of the high-pressure admission and thus the surface contact between the sealing surface of the head and the surface of the intermediate valve seat act high adhesion forces, which the reopening of the intermediate valve for

Completing the injection process complicate, in particular, the temporal precision of the termination of the

Injection process can be deteriorated.

The object of the invention is therefore to develop a generic fuel injector such that the above disadvantages can be avoided, with a sliding fit with larger tolerances should be made possible for cost reasons.

To achieve this object, it is proposed that the sealing surface of the head and the surface of the intermediate valve seat are designed such that they produce a throttled fluid connection between the high-pressure admission and the sliding fit in the closed position of the intermediate valve.

Preferably, the sealing surface of the head and the surface of the intermediate valve seat are aligned with each other, preferably inclined to each other that they rest in the closed position of the intermediate valve radially outside sealingly and radially inwardly an axially increasing throttle gap form for the throttling of the high pressure zulass Valve space down. Since the sealing surfaces are circular around the Valve axis are shaped, comes theirs _. Inclination due to their different conicity.

By a . Such a configuration of the corresponding surfaces of the head and the intermediate valve seat, a throttling of the high-pressure admission can be achieved, which is so strong that the still possible flow between the high pressure admittance and the valve chamber does not affect the remaining function of the fuel injection valve. The throttling achieved directly at the mouth of the high-pressure admission is so strong that the sliding fit between the shaft and the intermediate part can have relatively large tolerances, in particular in the range of one hundredth of a millimeter. Thus, the intermediate valve member, in particular its shaft, and the intermediate part, in particular its bore receiving the shaft, can be manufactured with greater tolerances, which leads to cost savings.

The preferably formed between the two sealing surfaces of the head and the intermediate valve seat throttle gap leads to an avoidance or at least a strong reduction of adhesion forces between these sealing surfaces, since ^' they rest in the closed position of the intermediate valve only along the circumference of the head together and a circumferential ring seal form, whereby a flat contact between them is avoided. Thus, a precise control of the termination of the injection process by opening the intermediate valve is made possible, since at the beginning of the opening of the intermediate valve member no adhesion forces are to be overcome. In addition to a preferred mutually inclined configuration of the sealing surfaces of the head and the intermediate valve seat in the form of cones of different conicity, it is also conceivable that at least one of these surfaces is curved, wherein the surface then forms a kind of dome. However, the curvature need not necessarily be part of a circular arc, but may also be part of any conic section, in particular also be designed parabolic. In such an embodiment, a throttle gap with at least one curved interface (sealing surface) is formed between the sealing surfaces. If both surfaces are curved in the same direction, one of the sealing surfaces has a smaller radius of curvature than the other, so that the radially inwardly widening throttle gap can be formed. Of course, two mutually convex curves could be provided between which the throttle gap is executed.

While the control chamber and the valve chamber are permanently connected to one another via an exact throttle passage, the intermediate valve, moreover, permanently separates these two chambers 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 the 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 essentially solely dependent on the cross section of the throttle passage. At the Sqhliessen the outlet from the valve chamber by means of the actuator assembly opens the intermediate valve quickly and releases the connected to the high-pressure chamber, previously throttled by the throttle gap high-pressure outlet of large cross-section, causing a quick termination of the injection process.

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 as large, 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.

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

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

Fig 2.:., In longitudinal section and in an enlarged view of a partial section of the ^• present invention, the fuel injection valve of Figure 1 with the control device for controlling the opening and closing movement of the ^• rapid injection valve member;

Fig. 3: a longitudinal section and an enlarged view of a partial section of a first alternative design variant of the control device of the fuel injection valve of Fig. 1;

4 shows a longitudinal section and in an enlarged view a partial section of a second alternative design variant of

Control device of the fuel injection valve of Fig. 1;

Fig. 5: in longitudinal section and in strong, enlarged. Representation of a partial section of the

Control device of Fig. 4;

6 shows a longitudinal section and a greatly enlarged view of a partial section of a construction variant of the control device of FIG. 5;

7 shows a longitudinal section and in an even more enlarged view a partial section in the region of a throttle gap of the control device of FIG. 5.

Figure 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 nut trained 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 injector 1 is connected in a known manner to a fuel supply which supplies fuel to fuel injector 1 under very high pressure, for example up to 1800 bar or higher. 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 ', which is desachsiert relative to the housing axis 8, there is an actuator 24, which is either, as shown, designed as a piezo actuator 26 or alternatively 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 is shown and described in detail in connection with FIG. A low pressure fuel return 50 relieves fuel to control the movements of the injector member and directs this fuel away from the fuel injector 1.

In the description of the embodiments of the fuel valve shown in FIGS. 2-4, the same reference numerals are used for the corresponding parts as in connection with the description of the fuel injection valve 1 shown in FIG. 1. Further, only the differences from FIG 1 shown fuel injector 1 and already described above embodiments.

Figure 2 shows a longitudinal section and in an enlarged view of a portion of the inventive fuel injection valve 1 of Figure 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, continuous opening of the first intermediate plate 12 and is guided on this with a sliding fit 58 '. The head 60 of the intermediate valve member 56 is located, displaceable in the axial direction, in a recess 62 of the guide sleeve 36. The recess 62 is connected by radial passages 56 '' in the head 60 with the control chamber 54 hydraulically permanently connected and thus part of the control chamber 54th Der Head 60 is pressed by a, on a lower surface 14a of the second intermediate plate 14 supporting, small compression spring 66 to 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 space 70 in the second intermediate plate 14; a recess extending through the second intermediate plate 14 and bounded 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 shown in FIG. 2 immediately adjacent to the control chamber 54, could alternatively sunk along the in the axial direction be made through the intermediate valve member 56, hydraulic connection bore 68a or at the other end of the connecting bore 68a 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 Piezoaktuator 26 (Fig.l) Aktuatorventilglied 72, which bears in its closed position with its conical sealing surface 72a sealingly formed on a housing body 10, annular valve seat DS. The valve seat DS is formed by the mouth of an exhaust passage 73 formed in the housing body 10; this outlet passage 73 leads to the low pressure fuel return 50 (Fig. 1). An actuator valve member spring 74 exerts a constant, but in comparison to the fuel pressure force small spring force in the direction of the valve seat DS on the Aktuatorventilglied 72.

A high pressure admission in the form of a bore 76 of relatively large cross section in the first intermediate plate 12th connects the control chamber 54, via a lateral passage 76a in the second intermediate plate 14, with the bore 38. With closed intermediate valve 56 ', this connection is interrupted, in its open position, the intermediate valve 56' is a circular cylindrical passage. The lateral passage 7βa can alternatively be made in the first intermediate plate 12.

The dimensions of the above-mentioned outlet passage 73, the bore 76 and the throttle passage 68 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 approx. 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 head 60 of the intermediate valve member 56 has a sealing surface 61 directed towards a surface 57 of the valve seat 59 formed in the intermediate member 17, in particular in the first intermediate part 12. The sealing surface 61 and the surface 57 are inclined relative to each other so that they rest in the closed position of the intermediate valve 56 'radially outside sealingly against each other and radially inwardly an axially increasing throttle gap 77 (Fig. 5-7) form for throttling of the high-pressure tap 76 toward the valve space 70, which will be explained in more detail below with reference to FIGS. 4 to 7.

The operation of the fuel injection valve 1 is as follows: the piezoactuator 26 is energized, expands and opens by movement of the Aktuatorventilgliedes 72 down the valve seat DS and thus the outlet passage 73. This position of the Aktuatorventilgliedes 72 is in Fig. 2 with a dashed line shown. 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 (high pressure admission) flows into the control chamber 54 until the intermediate valve 56 is closed, which happens when the sealing surface 61 of the head 60 against the surface 57, ie the lower Surface 12a comes to concern, the sealing surface 61 and the surface 57 only come into contact radially outward with each other and thus form a high-pressure admission 76 separating from the control chamber 54 ring seal. At this time, the pressure in the control chamber 54 has dropped little. Because of the above-indicated throttling of the high-pressure inlet 76 through the head 60 of the intermediate valve member 56 and also because of the sliding fit 58 ', which, except for a small and insignificant for the separation function leakage, continuously existing hydraulic separation point between the control chamber 54 and the valve chamber 70th causes only a very small amount of fuel from the high-pressure regulator 76 can enter the valve chamber 70, where the pressure has already fallen sharply at this time. Now. - When the intermediate valve 56 is closed - the pressure in the control chamber 54, due to fuel draining through the throttle passage 68, fall off 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 completely flows out, 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 from the system pressure in the connected to the bore 76 throttle gap 77 and in an around the shaft 58 extending around annular groove 79 and in small proportion the force of the spring 66 moves down again and opens the intermediate valve seat 56 '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. The realization of separate pre- or post-injections with a main injection in between and with very short time intervals between the individual injections, ^'the intermediate valve member 56 28 again in the closing direction of the intermediate valve 56 by re-energizing the piezoelectric actuator 26 already during the closing movement of the injection valve member' can be moved, because the control chamber 54 and the distribution chamber 70, due to the sliding fit 58 and the throttling of Hochsruckzulasses 76, are hydraulically practically separated. The subsequent injection may connect directly to the end ^'of the preceding and the distance between the individual, separate injections .can practically to zero can be shortened. 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 cars or truck engines, as well as much larger fuel injectors, which, for example, in locomotives Earthmoving machinery, power plants and ships.

3 shows in longitudinal section and in an enlarged view a partial section of a first alternative construction 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 one outlet passage 110 which communicates via a passage 108 in the first Intermediate plate 104 is hydraulically connected to the back of the shaft 58 of the intermediate valve member 56. The intermediate portion 17 forming the intermediate plates 104 and 106 ^■ turn could be realized as a single workpiece .. Alternatively, the passage may also be made in the second intermediate plate 106 108th The valve chamber 70 of Fig. 5 is of particularly small volume content. The cross section of the exhaust passage 110 may be substantially larger than the ^" cross section of the throttle passage 68. The actuator shaft 112 blocks the outlet side of the exhaust passage 110 in the position shown in Fig. 3 so that no injection can take place as the actuator shaft 112 moves upward is the fuel pressure in the outlet passage 110 and the passage 108 drops rapidly, so that the fuel injection valve, in a manner analogous to in In connection with FIGS. 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 ^■ at, energization of the actuator shaft in a known manner 112th

FIG. 4 shows, in a longitudinal section and in an enlarged view, a partial section of a second alternative construction variant of the control device 88 of the fuel injection valve. 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 inter-valve member 56, for permitting intermittent injections, throttles the flow of hydraulic fluid through the bores 96 (high pressure bleeds) due to the formation of the throttle gap 77 between the surface 57 and the sealing surface 61 of the intermediate valve member head 60, with this construction of the intermediate valve 56 'of the passage in the recess 62 is closed, wherein the passage to the sliding fit 94''of the shaft 58 is strongly throttled with the intermediate element 94. By the tight throttling of the flow between. the high pressure passages forming bores 96 and the valve space 70, the sliding fit 94 '', if desired, can be made less accurate and their play can, instead of typically 2 to 6 microns of a close sliding fit as known in the art, up to 50 microns, so be several hundredths of a millimeter. Incidentally, this also applies to the embodiments shown in the other figures. However ^• must sliding fit 94 '' together with the throttle gap 77 cause such hydraulic separation point at least, which will produce a sufficient pressure difference, so that after actuation of the actuator assembly 24 (FIG. 1), the intermediate valve member 56 greatly slows rapidly the bores 96. Incidentally, the outlet of the bores 96 may be widened in the recess 62 on the circumference about the axis 102 in order to obtain a larger flow area with small stroke of the intermediate valve member 56. One then obtains an extension in kidney shape or a groove which extends in the circumferential direction of the recess 62 and the sliding fit 94 ' ^/ . Furthermore, the control device 88 of Figure 4, unlike those of the previous figures, no compression spring 66, which also in. can be realized in the preceding 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.

Figure 5 shows a greatly enlarged partial sectional view of the intermediate valve member 56 of Figure 4. In this enlargement and even better from the accompanying detailed view of. FIG. 7 shows that, in the illustrated closed position of the intermediate valve (during the injection process), the sealing surface 61 of the head 60 of the intermediate valve member 56 and the surface 57 of the valve seat 59 extend radially outwards contact each other and form a - line-shaped - ring seal 59a, which prevents the flow of high-pressure fuel from the Hochdruckladässen 96 into the control chamber 54 and the recess 62. The sealing surface 61 and the surface 57 are, however, formed inclined to each other or have a different conicity, so that, starting from the radially outer ring seal formed 59a of the throttle gap 77 is formed between them, the .radial inward in the axial direction is greater. The sealing surface 61 and the surface 57, which in this embodiment are both conical (in the same direction), include an acute angle, ie an angular difference α. This angle difference α is less than 2 °, preferably between 0.5 ° and 1.5 °, in particular 1 °, to produce the desired throttle effect at the high-pressure ports 96, ie to reduce the flow area in the throttle gap 77 sufficiently, so that by means of the intermediate valve member 56, the desired Control of the fuel injection valve is ensured. In contrast, the angle of the cones may be substantially greater, between 10 ° and 30 ° ^' or even greater, measured at a right angle to the housing axis 8 extending plane.

The mutually inclined configuration of the sealing surface 61 and the surface 57 have the advantage that between the two surfaces in the closed position of the intermediate valve no or the opening movement of the intermediate valve member 56 hardly adversely affecting adhesion forces, so that the movement of the intermediate valve member 56 down into the open position of Intermediate valves can be done with less effort and more precise. This allows even more accurate control of the intermediate valve member 56, so that the timing of the completion of the injection process can be determined highly precisely. Incidentally, the throttle gap 77 and the sliding fit 94 '' act as series-connected throttles, wherein the flow of fuel through these throttles for the correct and precise operation of the control device is negligible. Due to the strong throttle effect through the throttle gap 77, the sliding fit 94 '' can be provided with a larger tolerance in the range of a few hundredths of a millimeter.

If the smallest ^■ flow cross-section between the Hochdruckzulässeri 96 and the annular groove 79, in the throttle gap 77, is appreciably smaller than the leakage cross section in the sliding fit 94 '' is - in the closed state of the intermediate valve 56 '- the pressure in the clearance gap 77 is substantially smaller than in the Control chamber 54, which can to bending the head 60, in the manner of a plate spring, earlier, especially when the head 60 is dimensioned relatively thin. This in turn leads to a reduction of the throttle gap 77 and thus to an additional reduction of the leakage from the Hochdruckzulässen 96 in the valve chamber 70, wherein the undesirable adhesion between the intermediate part 17 and the head 60 is avoided.

As already described above in the operation of the fuel injection valve according to the embodiment of FIG. 1, the fuel flow is interrupted from the valve chamber 70 into the low-pressure fuel outlet by closing the outlet passage 110. A rapid pressure equalization then takes place between the control chamber 54 and the valve space 70. allowing the in the high pressure upcoming high pressure across the throttle gap 77 and guided around the shaft 58 around annular groove 79 effect unfolded on the intermediate valve member so that it moves under the high pressure effect down and thus the intermediate valve 56 'is opened, the high-pressure inlet 96 then again in fluid communication with the Control chamber 54 stand until the outlet drift 110 is released again to the low-pressure fuel outlet 50 (FIG. 1). The maximum opening stroke is given by the end face 78b of the sleeve 78.

Figure 6 shows an alternative embodiment of the sealing surface 61 and the surface 57 of the valve seat 59. Although the two, the throttle gap 77 forming surfaces are again inclined to each other, but the sealing surface 61 of the head 60 is now considered to be substantially horizontal

- i. to the housing axis 8 at right angles extending - flat surface formed, whereas the surface 57 is designed conical, so that between them also the throttle gap 77 forming angle difference α is formed.

Of course, the surface 57 could be substantially horizontal - at right angles to the housing axis. 8

- Run, in which case the sealing surface 61 of the head would have to fall from radially outward to radially inward in the axial direction to obtain the advantageous throttle gap 77. Furthermore, it is also conceivable that at least one of the two sealing surfaces is curved, such that, starting from the ring sealing area, it extends in an arcuate manner radially inwards.

It is also possible to form the surface 59 of the valve seat 59 and the surface 61 of the head 60 parallel to each other and radially the one or both of these surfaces outside with one ,. to limit the ring seal 59a, forming, protruding annular sealing bead, which, however, measured in the radial direction, should have a small extent to keep the Abhäsionswirkung small.

The embodiments of the sealing surface 61 and the surface 57 described with reference to FIGS. 5 to 7 can be used in all alternative embodiments of the control device of FIGS. 1 to 4

In the embodiments shown is the

Opening cross-section of the outlet passage at least two

Times as large as the cross section of the exact throttle passage 68th

Of course, ^'the characteristics of the control devices of the fuel injection valves, in particular the design of the sealing surfaces of the intermediate valve member head and of the intermediate valve seat of the present invention or in ^{individually'} other combinations than find those shown here, use can.

Claims

claims

1. Fuel injection valve (1) for the intermittent injection of fuel into the combustion chamber of an internal combustion engine, with

a housing (6) having a housing body (10) and a nozzle body (16) with an injection valve seat (44),

a high-pressure chamber (42; 90) arranged in the housing (6) and communicating with a high-pressure fuel inlet (20) and the injection valve seat (44),

an injection valve member (28), which is longitudinally adjustable in the housing (6) and cooperates with the injection valve seat (44),

a compression spring (34) on the one hand on the injection valve member (28) is supported and this with a directed towards the injection valve seat (44) closing force and on the other hand on a guide sleeve (36, 78) supported while the guide sleeve (36; ) to an intermediate part (17) presses sealingly, wherein the ■ guide sleeve (36; 78) together with a guided in the guide sleeve (36; 78) control piston (28 ') of the injection valve member (28) a control chamber (54) against the high-pressure chamber ( 42, 90),

a control device (52; 52 ^r ; 52 ''; 52 ' ¹ ', 88) for

Controlling the axial movement of the

Injection valve member (28.) by changing the

Pressure in. Control room (54), with an intermediate valve

(56 '), whose intervening schedule (56) in Open position one with the fuel high pressure inlet (20) in connection, standing high-pressure admission (76, 96) in the control chamber (54) releases and in the closed position the high-pressure admission (76, 96) in the control chamber (54) interrupts and the control chamber (54) of a Valve chamber (70) - except for a in the intermediate valve member (56) formed throttle passage (68) - separated, and

an electrically actuated actuator assembly (24) for connecting the valve space (70) to and separating the valve space (70) from a low pressure fuel return (50);

wherein the intermediate ^{valve member ■} (56) is mushroom-shaped with a guided in sliding fit in the intermediate part shaft (58) and a head (60) with its sealing surface (61) in the closed position of the intermediate valve member (56) at least partially on a surface (57). an intermediate valve seat (59) formed on the intermediate part (17) in order to separate the high-pressure admission (76, 96) from the control chamber (54),

characterized in that the sealing surface (61) of the head (60) and the surface (57) of the intermediate valve seat (59) are designed such that they in the closed position of the intermediate valve (56 ') a throttled fluid connection between the high-pressure admission (76, 96) and the Gleitpassung ^' manufacture.

2. Fuel injection valve according to claim 1, characterized in that the sealing surface (61) of the head and the surface (57) of the intermediate valve seat (59) are formed inclined to each other so that they rest in the closed position of the intermediate valve (56 ') radially outside sealingly and radially inwardly an axially increasing throttle gap (77) form for the throttling of Hochdruckzulasses toward the valve chamber (70).

3. Fuel injection valve according to claim 2, characterized in that the throttle gap (77) and the sliding fit (58 ', 94' ') - in series, the throttling of the high-pressure admission (76, 96) to the valve chamber (70) produce.

4. Fuel injection valve according to one of claims 1 to 3, characterized in that the sealing surface

(61) of the head (60) and / or the surface (57) of the intermediate valve seat (59) is or are conical.

5. Fuel injection valve according to one of claims 1 to 4, characterized in that between the sealing surface (61) of the head (60) and the surface (57) of the intermediate valve seat (59) an angular difference (α) of less than 2 °, preferably smaller or equal to 1 ° is formed.

6. Fuel injection valve according to one of claims 1 to 5, characterized in that the intermediate valve (56 ') in the open position has a substantially larger cross section than the cross section of the throttle passage (68).

7. Fuel injection valve according to one of claims 1 to ^' 6, characterized in that the intermediate valve member (56) by the force of a Compression spring (66) is constantly acted upon in the direction of the open position.

8. Fuel injection valve according to one of claims 1 to 6, characterized in that the intermediate valve member (56) is actuated exclusively by the double-acting hydraulic forces.

9. Fuel injection valve according to one of claims 1 to 8, characterized in that the actuator assembly (24) comprises an actuator valve member through which an outlet passage (73, 110) from the valve chamber (70) to the low-pressure fuel return (50) can be closed or opened ,

10. BrennistoffeiΩ.spritzΛrent.il according to claim 9, characterized in that the outlet passage (110), the

Intermediate valve member (56), the guide sleeve (78) and the injection valve member (28) on a longitudinal axis (102) of the fuel injection valve are arranged.