EP1431567B1 - Fuel injection valve for internal combustion engines - Google Patents

Abstract

The fuel injection valve has a housing with a high pressure inlet for fuel, a spring-loaded injection valve element (22), a dual action control piston (60) bounding a high pressure chamber (20) on one side and a control chamber (62) on the other side, a control body (72) bounding the control chamber and valve element in the form of a plate-shaped tongue that is fixed at one end.

Description

The present invention relates to a fuel injection valve for intermittent fuel injection into the combustion chamber of an internal combustion engine having the features in the preamble of claim 1.

A fuel injection valve having the features in the preamble of claim 1, is in the EP-A-0 426 205 and in the EP-A-0 228 578 disclosed. In this fuel injection valve, a control chamber is peripherally from a housing of the fuel injection valve and, viewed in the axial direction, on the one hand by a double-acting control piston of an injection valve member and on the other hand by an intermediate valve body which leaves an annular gap between itself and the housing, and a ring gap bounding the control body, the housing is fixed, limited. Between the control piston and the intermediate valve body, a compression spring is arranged. In the axial direction passes through the intermediate valve body through a stepped bore, which exerts a throttle effect. In extension of this bore extends through the control body through another bore, which is connectable by means of an electromagnetically operated pilot valve with a low-pressure chamber and separated from this. In this axially extending bore in the control body opens a further bore, which is in communication with a circumferential annular groove in the control body, which in turn is connected to the high pressure inlet of the fuel injection valve. From this annular groove extend a plurality of bores to the intermediate valve body facing end face of the control body.

These bores are closed by the valve body abutting the control body of this.

In another fuel injection valve, which in the EP-A-0 675 281 and US-A-5,655,716 is disclosed, a control piston of a nozzle needle projects into a control chamber. Above this control piston, a valve is arranged, the coaxially extending to the control piston valve body is laterally sealingly guided in the valve housing. The valve body projects with the one, the control piston facing end face in the control chamber and the other end in a communicating with a drain line via a control valve auxiliary chamber which is connected to the control chamber via a valve body passing through the throttle bore. This throttle bore and thus the control chamber are connected via a transverse further throttle bore in the valve body permanently connected to the high pressure part of the fuel injection valve. A connected to the high-pressure part around the valve body extending annular chamber is bounded above by a valve seat cooperating with the valve seat. In the closed position of the nozzle needle, the control piston to the valve body at a distance, while in the open position of the nozzle needle, the control piston abuts against the lower end face of the valve body. Immediately after the closure of the control valve, a pressure build-up initially takes place in the additional chamber through the transverse throttle bore, as a result of which the valve body moves against the control piston and thus causes an independent opening of the valve seat. Through this opening flows an additional influx of the high-pressure control medium into the additional chamber, whereby the nozzle needle is brought from the valve body at an increased speed in the closed position.

After the closed position is reached, the valve body is due to the pressure build-up in the control chamber and with spring force support moved back up until it rests against the valve seat.

The older one EP-A-1 118 765 discloses a fuel injector for internal combustion engines, the needle-like injection valve member has a stepped control piston which engages in a force acting as a closing spring for the injection valve compression spring sleeve. On the side facing away from the spring, the sleeve is supported on a control body, which is fixedly arranged in a housing of the fuel injection valve. The sleeve has an extension formed by a shoulder. In this extension, a sleeve-shaped valve body is arranged, wherein between this and the sleeve, a gap is present. The valve body interacts with its axial end faces on the one hand with the shoulder and on the other hand with the control body, wherein the length of the valve body is slightly smaller than the distance between the shoulder and the control body, so that the valve body in the axial direction by a small stroke hin- and can move. The smaller diameter part of the control piston is guided in a tight sliding fit in the valve body. Between the control body facing away from the end of the valve body and the larger diameter part of the control piston, an annular space is formed, which is connected to a inside of the housing and fed via a high pressure inlet with fuel high pressure chamber via a gap which is between the corresponding part of the sleeve and the larger diameter part of the control piston is formed. A control room is on the one hand limited by the control piston, on the other hand by the control body and the periphery of the sleeve-shaped valve body. A control passage having a constriction acting as a throttle extends through the control body from the end face delimiting the control space to the opposite end face, which delimits a low-pressure space. The control passage is connected by means of an electromagnetically actuated pilot valve with the low-pressure chamber or can be separated therefrom.

It is an object of the present invention to provide a generic fuel injection valve which is ready for a further injection process quickly.

This object is achieved by a fuel injection valve having the features of claim 1.

In addition to simplicity, the fuel injection valve according to the invention is at the same time extremely compact. It takes up little space. The properties of the fuel injection valve can be designed in a simple manner adapted to the requirements in the options provided by the injection valve according to the invention. In particular, the inventive fuel injection valve is again very quickly ready for another injection process. Due to the available damping options a very long life can be achieved. Further advantages will become apparent from the following description of the embodiments.

Preferred embodiments are specified in the dependent claims.

Fig. 1

im Längsschnitt ein Brennstoffeinspritzventil;

Fig. 2

ebenfalls im Längsschnitt und bezüglich Fig. 1 vergrössert einen Teil des dort gezeigten Einspritzventils mit der Steuervorrichtung und der Elektromagnetanordnung;

Fig. 3a

einen Querschnitt durch das Einspritzventil der in Fig. 2 mit III-III bezeichnet ist;

Fig. 3b

in perspektivischer Darstellung Teile zur Abstützung der Schliessfeder des Brennstoffeinspritzventils;

Fig. 4

im Längsschnitt und bezüglich Fig. 1 und 2 vergrössert einen Teil des dort gezeigten Brennstoffeinspritzventils mit der Steuervorrichtung;

Fig. 5

in gleicher Darstellung wie Fig. 4 eine erste Ausbildungsform der erfindungsgemässen Steuervorrichtung;

Fig. 6

in gleicher Darstellung wie Fig. 4 und 5 eine zweite Ausbildungsform der erfindungsgemäss ausgebildeten Steuervorrichtung;

Fig. 7

in gleicher Darstellung wie Fig. 4, 5 und 6 eine Ausbildungsform der Steuervorrichtung für ein Einspritzventil, das anstelle eines Schieberventils ein Blattfederventil aufweist;

Fig. 8a

einen in der Fig. 7 mit VIII-VIII bezeichneten Querschnitt durch den dort gezeigten Teil des Brennstoffeininspritzventils;

Fig. 8b

in perspektivischer Darstellung die in der Steuervorrichtung gemäss den Fig. 7 und 8a verwendete Blattfeder;

Fig. 9a

in einem Schnitt entsprechend jenem der Fig. 8a eine weitere Ausbildungsform der Steuervorrichtung eines Einspritzventils mit einer Blattfeder;

Fig. 9b

in perspektivischer Darstellung das Blattfederelement beim Einspritzventil gemäss Fig. 9a; und

Fig. 10

im Längsschnitt und bezüglich Fig. 1 und 2 vergrössert einen Teil des dort gezeigten Brennstoffeinspritzventils mit der Elektromagnetanordnung.

The invention will be explained in more detail with reference to the drawing. It shows purely schematically:

Fig. 1

in longitudinal section, a fuel injection valve;

Fig. 2

also in longitudinal section and with respect Fig. 1 enlarges a part of the injection valve shown there with the control device and the solenoid assembly;

Fig. 3a

a cross section through the injection valve of in Fig. 2 designated III-III;

Fig. 3b

in perspective parts for supporting the closing spring of the fuel injection valve;

Fig. 4

in longitudinal section and in relation Fig. 1 and 2 enlarges a part of the fuel injection valve shown there with the control device;

Fig. 5

in the same representation as Fig. 4 a first embodiment of the inventive control device;

Fig. 6

in the same representation as Fig. 4 and 5 a second embodiment of the inventively designed control device;

Fig. 7

in the same representation as Fig. 4 . 5 and 6 an embodiment of the control device for an injection valve having a leaf spring valve instead of a spool valve;

Fig. 8a

one in the Fig. 7 with VIII-VIII designated cross section through the part of the there shown Eini fuel injection valve;

Fig. 8b

in a perspective view in the control device according to the Fig. 7 and 8a used leaf spring;

Fig. 9a

in a section corresponding to that of Fig. 8a another embodiment of the control device of an injection valve with a leaf spring;

Fig. 9b

in a perspective view of the leaf spring element according to the injection valve Fig. 9a ; and

Fig. 10

in longitudinal section and in relation Fig. 1 and 2 enlarges a part of the fuel injection valve shown there with the solenoid assembly.

Fig. 1 shows an axial section through a fuel injection valve 10. This comprises a tubular housing 12 to which at one end a valve seat member 14 and the other end an electromagnet assembly 16 for the electromagnetic control of the fuel injection valve 10 are attached. The housing 12 has a radially extending bore serving as a high-pressure inlet 18, through which fuel is introduced under a high pressure (200-2000 bar or more) into a housing-limited high-pressure space 20 which extends in the axial direction to the end of the valve seat element of the housing 12 extends. In this high-pressure chamber 20 is a needle-like injection valve member 22 whose axis 24 coincides with the axis of the hollow cylindrical housing 12. By means of a between the Housing 12 and the injection valve member 22 existing annular space 25, the valve seat member 14 is fluidly connected to the high pressure inlet 18. In the interior of the tubular housing 12 is further a hydraulic control device 26 for the injection valve member 22, which below in connection with the Fig. 2 and 4 will be described in more detail.

The housing 12 passes through a connection sleeve 28 with a thread flange 30 projecting in the radial direction, into which a high-pressure connecting piece 32 is threaded. How this in particular the Fig. 2 can be removed, the wall of the high-pressure connection piece 32 in the housing 12 facing end portion is conically tapered, so that the width of the end-side annular sealing surface 34 is smaller than the thickness of the wall of the high-pressure connection piece 32 at the remaining locations, resulting between the sealing surface 34 and the cooperating mating surface 36 on the housing 12 when tightening the high-pressure connection piece 32 results in a high surface pressure and thus a high-pressure-tight connection. The high-pressure inlet 18 of the housing 12 is located centrally in the counter-sealing surface 36. The connection sleeve 28 is fastened to the housing 12 by means of the high-pressure connection piece 32. In this context, it should be mentioned that the housing 12 on the outside, for the axial positioning of the connection sleeve 28, may have a shoulder. In a variant, not shown, the high-pressure connection piece 32, the conical taper on its outer side, with the same effect as in the illustrated taper on the inner wall of high-pressure connection piece 32. The high-pressure connection piece 32 can be pressed by other means than a thread on the sealing surface 34 become.

Again Fig. 1 removable, the valve seat member 14 is fixed in a known manner by means of a union nut 38 on the housing 12. From the cone-shaped free outer end face 40 of the valve seat member 14 forth run in a known manner injection nozzle holes 42, which open into the high-pressure chamber 20. A likewise conically shaped inner end face of the valve seat member 14 is formed as a valve seat 44 and intended to cooperate with the counter-shaped end portion of the injection valve member 22. When the injection valve member 22 is in the closed position, this end region separates the injection nozzle holes 42 from the high-pressure chamber or connects them to that when it is lifted from the valve seat 44 in the injection position.

Like this the Fig. 2 and 4 across from Fig. 1 enlarged show, the injection valve member 22 is biased by means of a closing spring designed as a compression spring 46 in the closing direction. The shaft 48 of the injection valve member 22 has a shoulder 50 on which support two Halbstützflansche 52 - see Fig. 3b - In the assembled state of a first ring 54 includes and held together. The one end of the closing spring 46 is supported on this first ring 54. The other end is supported on a second ring 54 ', which sits on a slot having a one-piece support flange 56. This is in turn on the front side of a substantially hollow cylindrical sleeve 58, which will be described in more detail in connection with the control device 26. The part of the injection valve member 22 slightly tapered in diameter following the shoulder 50 passes through the support flange 56 with clear play, while the Halbstützflansche 52 sit practically spielfei on the injection valve member 22 in a preferred manner. Since the wall of the sleeve-shaped part of the Halbstützflansche 52 may be formed thin, it is possible to form the closing spring 46 in the inner diameter very slim; this may correspond approximately to the outer diameter of the injection valve member 22 below the shoulder 50. Further, the sleeves 54,54 'can be used for the compensation or the compensation of length deviations. By selecting from sleeves 54,54 'different thickness, the force of manufacturing tolerances subject closing spring 46 a series of fuel injection valves can always be kept the same.

The control device 26 is based on Fig. 4 described. It can be seen that the injection valve member 22 in its end remote from the valve seat member 14 has a double-acting control piston 60 which is in the sleeve 58 in a close sliding fit - ie with a clearance of about 1 to 10 microns - out. The control piston 60 limits on the one hand the high-pressure chamber 20 and on the other hand a control chamber 62 which is peripherally bounded by the sleeve 58. In the sleeve 58, a slide valve body 64 of a slide valve 66 is further arranged in a close sliding fit and guided freely movable in the direction of the axis 24. A first end face 68 facing the injection valve member 22 likewise delimits the control chamber 62. A second end face 68 'facing away from the first end face 68 is designed as a sealing surface and intended to bear in a sealing position of the slide valve body 64 in a sealing manner on a front side of a control body 72 designed as a slide valve seat 70 , which is fixedly arranged in the housing 12, for example by means of a shrink connection.

With respect to the axis 24 arranged eccentrically, extends from the first end face 68 to the second end face 68 'through the slide valve body 64 therethrough a throttle passage 74. On the second end face 68' is in the slide valve body 64, a hydraulic connection 76 except that of the this side conically widened mouth the throttle passage 74 extends in the radial direction to the axis 24 and beyond. However, the connection 76 is enclosed on all sides by a protruding edge. The hydraulic connection 76 is advantageously designed in such a way that the recessed surface has a certain dimension in order to achieve an optimal response of the slide valve 66 for ending the injection process.

In a variant, not shown, the throttle passage 74 is arranged on the axis 24. In this case, the hydraulic connection 76 is omitted.

In the control chamber 62 designed as a compression spring spring element 78 is arranged, which is supported on the one hand on the control piston 60 and on the other hand on the slide valve body 64. The spring element engages around a central projection 80 of the control piston 60 and the force generated by it is substantially smaller than that of the closing spring 46th

The control body 72 has a control passage 82 extending coaxially with the axis 24 and having an orifice restriction 82 'in an end region facing away from the slide valve body 64. The hydraulic connection 76 connects the control passage 82 with the throttle passage 74, even when the slide valve body 64 sealingly abuts the control body 74. The sleeve 58 is supported on the front side on Control body 72 from; in their the control body 72 facing the end region on the radially inner side a circumferential recess 84 is present, which forms an annular groove with this in sealing position befindendem slide valve body 64, which via a slot 86 in the sleeve 58 and extending through at least one in the axial direction Flow gap 88 which is formed between the inner wall of the housing 12 and a flattening on the outside of the sleeve 58 is connected to the high-pressure chamber 20. As a result, a gap 89, which forms when the slide valve body 64 moves away from the control body 72, is connected to the high-pressure chamber 20, and the entire second end face 68 'of the slide valve body 64 is subjected to high pressure. The control body 72 has an inclined surface 90, from which a throttle inlet 92 leads into the control passage 82 in order to connect it permanently to the high pressure space 20. The throttle inlet 92 opens into the control passage 82 between the throttle restriction 82 'and the spool valve seat 70. An orifice arranged at 90 ° to the axis 24 with a ground surface in the control body or an annular groove on the control body could also be used. The cross-sections of the recess 84, the slot 86 and the flow gap 88 are designed substantially larger than the cross sections of the throttle passage 74, the throttle restriction 82 'and the throttle passage 92, so that no appreciable throttling arise, and the pressure in the recess 84, in the slot 86 and in the flow gap 88 is substantially the same as that in the high pressure inlet 18 and the high pressure chamber 20th

Like this Fig. 4 and especially from Fig. 2 and 3a is apparent, on the tubular housing 12, from the side of the electromagnet assembly 16 forth, another Screwed union nut 94, which centrally has a through hole 96 with three circumferentially distributed longitudinal grooves 96 '. In the through hole 96, a valve pin 98 is slidably disposed in the axial direction and guided radially. On the control body side, the through-bore 96 has an expanding recess 97, which favors the outflow of the fuel, which is relieved during the injection from the throttle restriction 82 ', into the longitudinal grooves 96'. Instead of the longitudinal grooves 96 'and one or more holes could be used, which connect the recess 97 with the low-pressure chamber 106. In this case, the bore 96 would guide the valve pin 98 in the entire circumference radially.

The union nut 94 has a hexagon 95 ( Fig. 3a ), so that it can be tightened with the required torque. Other clamping means, not shown, are also used.

The union nut 94 holds on the one hand the control body 72, which is possibly only slightly pressed in the housing 12, against the pressure in the high-pressure chamber 20 fixed and positioned this exactly. On the other hand, the nut 94 are assigned other important functions, which are described below and in the description of Fig. 10 are explained.

With non-energized solenoid 100 of the solenoid assembly 16, the valve pin 98 is held by an armature 102 of the solenoid assembly 16 in contact with the control body 72 where it closes the control passage 82. The valve pin 98 together with the control body 72, a pilot valve 104. On the control body 72 and the housing 12 facing away from the further union nut 94 is the low-pressure chamber 106, which is fluidly connected by connecting channels 108 in the solenoid assembly 16 with a low-pressure outlet port 110. In a known manner leads from the Niederdruckauslassstutzen 110 a line back to a fuel reservoir.

The armature 102 is acted upon by the force of a spring spring 112 designed as a compression spring, which holds the valve pin 98 in contact with the control body 72 via the armature 102 when the electromagnet 102 is not energized. If the solenoid 100 is energized, this pulls the armature 102 against the force of the armature spring 112, whereby the valve pin 98 can lift off the control body 72.

The functioning of the in the Fig. 1 to 4 The form of embodiment of the fuel injection valve 10 shown is as follows: starting from the state shown in the cited figures, in which the injection valve member 22 is in the closed position and the slide valve 66 is in sealing position on the slide valve seat 70. Further, the solenoid 100 is not energized, so that the valve pin 98 closes the control passage 82. In the control chamber 62, the same pressure is present as in the high-pressure chamber 20th

An injection cycle is triggered by the energization of the solenoid 100. In this case, the armature 102 is attracted, whereby the valve pin 98 can lift off the control body 72 and thereby the control passage 74 is connected to the low-pressure chamber 106. Since the throttle restriction 82 'has a larger flow cross-section than the throttle inlet 92, the pressure in the control chamber 62 begins to decrease. The Injector valve member 22 thereby moves away from valve seat 44 and releases injector holes 42. The injection process begins. In this case, fuel is displaced from the control chamber 62 through the throttle passage 74, the hydraulic connection 76 and the control passage 82 into the low-pressure space 106. During the entire opening operation of the injection valve member 22, the spool valve body 64 remains in abutment with the control body 72. The opening stroke of the injection valve member 22 is limited by the projection 80 of the injection valve member 22 abutting the spool valve body 64 leaving the throttle passage 74 exposed. Since the narrowest flow area of the throttle passage 74 is smaller than the cross section of the throttle restriction 82 ', the opening movement of the injection valve member 22 at a given pressure and given closing spring 46 is determined mainly by the throttle passage 74.

In a variant, not shown, the throttle passage 74 is positioned, and the end face of the projection 80 is designed so that the throttle passage 74 is closed by the projection 80 towards the end of the opening stroke. This e.g. in that the throttle passage 74 is positioned on the axis 24 and the end face of the projection 80 is made sealing. Thus, the end of the opening stroke is advantageously damped and the pressure in the control chamber 62 after the end of the opening movement is not or not fully aligned with the lower pressure in the control passage 82.

To end the injection process, the solenoid 100 is de-energized. This has the consequence that the armature 102 shifts the valve pin 98 in contact with the control body 72 under the force of the armature spring 112. The low-pressure side Mouth of the control passage 82 is closed. The pressure in the control passage 82 begins to increase due to the connection through the throttle inlet 92 with the high-pressure chamber 20, due to the pressure difference on both end faces 68, 68 'of the slide valve body 64 and the corresponding effective surfaces for moving the slide valve body 64 from the sealing abutment Control body 72 leads to the formation of the gap 89. At the same time, the closing spring 46 effects a movement of the injection valve member 22 in the direction of the valve seat 44. The negative pressure in the control chamber and the high pressure on the second end face 68 'causes the slide valve body 64 moves in the manner of a tandem movement together with the injection valve member 22 until it closes the valve seat 44 and thereby terminates the injection process into the combustion chamber of the internal combustion engine.

As a result of the flow of fuel through the throttle passage 74 in the control chamber 62 in this gradually equalizes the pressure to the pressure in the high pressure chamber 20, which causes the slide valve body 64 moves back under the force of the spring element 78 in sealing position. Now the fuel injector is ready for the next injection.

The hydraulic efficiency of this fuel injection valve 10 is very high; the controller consumes little fuel, resulting in a low flow of fuel back into the low pressure reservoir. Next plays the coaxiality of the injection valve member 22 to the spool valve 66 - compared with for example in the EP-A-1 118 765 disclosed embodiments of fuel injection valves - no matter what, for good Movement properties of both the injection valve member 22 and the slide valve body 64 leads.

Fig. 5 shows a first inventive embodiment of the control device 26. Incidentally, the fuel injection valve 10 is formed the same as in the Fig. 1 to 4 shown and described above. In the following, only the differences to that training form will be discussed. The same reference numerals are used for identical and equivalent parts.

The control piston 60 has in its, the high-pressure chamber 20 end facing a circumferential bead 114 with a stop shoulder 114 '. This is intended to cooperate with an integrally formed on the sleeve 58 counter-stop shoulder 116. For the rest, the bead 114 does not touch the sleeve 58. When the injection valve member 22 is in the closed position, the stop shoulder 114 'and the counterstop shoulder 116 are spaced from each other by a distance S ₁ . At the slide valve body 64, a further bead 118 is integrally formed, which forms a further stop shoulder 118 '. This is intended to cooperate with a formed on the sleeve 58 further counter-stop shoulder 120 together. This is formed by the axial boundary of the recess 84. When the slide valve body 64 is in the sealing position, the distance between the further stop shoulder 118 'and the further counterstop shoulder 120 is a length S ₂ . With S ₃ , the distance from the projection 80 of the injection valve 22 to the slide valve body 64 is designated with befindlichem in sealing position slide valve body 64 and befindlichem in the closed position injection valve member 22. The gaps formed by these distances S ₁ , S ₂ and S ₃ are designed so that the designated S ₁ gap is greater than that designated S ₂ and smaller than that designated S ₃ .

The slide valve body 64 has a further throttle passage 122 which extends between the first and the second end face 68, 68 'and which is closed by the slide valve seat 70 on the control body 72 when the slide valve body 64 is in the sealing position. When the slide valve body 64 is lifted off the control body 72, the further throttle passage 122 connects the control chamber 62 with the high-pressure chamber 20 in parallel with the throttle passage 74.

Next, the slide valve body 64 on the control body 72 side facing a chamfer 124, by means of which, depending on the size, the high-pressure acted upon active surface of the valve body valve 64 can be selected. The circle diameter at the outer edge of the slide valve seat 70 may thus be larger, equal to or smaller than the guide diameter of the slide valve 64 in the sleeve 58.

At the beginning of an injection operation and as long as the pilot valve 104 is opened, the further throttle passage 122 has no effect, the injection valve member 22 opens in the same way as in the embodiment according to FIG Fig. 1-4 until now the stop shoulder 114 'contacts the counter stop shoulder 116 and ends the opening process. Since S ₃ > S ₁ , the end face of the protrusion 80 does not contact the first end face 68 of the spool valve body 64. In embodiments with a stop shoulder 114 'on the injection valve member 22 and a counter stop shoulder 116 can be avoided that when opening the fuel injection valve 10, the injection valve member 22 abuts the spool valve body 64. This can extend the life.

Only when closing the pilot valve 104 and the associated lifting the slide valve body 64 from the slide valve seat 70 - in the same manner as described above - the further throttle passage 122 is released, whereby between the control chamber 62 and the high-pressure chamber 20, a more rapid pressure equalization takes place than at an embodiment without further throttle passage 122. This leads to an earlier and faster return of the slide valve body 64 in the sealing position. In other words, the fuel injection valve 10 is faster ready for another injection operation, which allows a pilot injection, a post-injection or a multiple injection with short time intervals. By dimensioning the further throttle passage 122, the return movement of the slide valve 66 can be adjusted according to the requirements.

Also, the spool valve body 64 in the embodiment of the fuel injection valve 10 according to the Fig. 1 to 4 can a further throttle passage 122 analog Fig. 5 exhibit.

A stroke limitation for the slide valve body 64 through the further stop shoulder 118 'and the further counterstop 120 also causes the slide valve body 64 to reach its sealing position again very quickly, since S ₂ <S ₁ . The tandem movement of slide valve body 64 and injection valve member 22 is released as soon as the further stop shoulder 118 ' at the other counterstop shoulder 120 comes to the plant. At the same time, by this measure, the impact of the injection valve member 22 on the valve seat 44 due to the throttled without tandem movement over the throttle passage 74 and the further throttle passage 122 refilling the control chamber 62 are damped with advantage. All these measures can be taken independently of each other in the other forms of training.

When in the Fig. 6 In the second embodiment of the fuel injection valve 10 according to the invention, the same reference numerals are used as in the embodiments described above and only the differences to those will be discussed.

The control body 72 is no longer seated in the tubular housing 12, but is placed on the front side of this and centrally held by a corresponding recess in the further union nut 94 and pressed sealingly against the upper end of the tubular housing 12. Centrally and in the axial direction passes through the control body 72 through the control passage 82; However, the throttle inlet 92 is now in the slide valve body 64. It opens into the throttle passage 74 and that on the relative to the narrowest cross section of the control body 72 side facing. Next, the throttle inlet 92 communicates via the recess 84, the gap 86 and the flow gap 88 with the high-pressure chamber 20th

The Indian Fig. 6 Sliding valve body 64 shown is like that of the embodiment according to Fig. 5 is equipped with a further throttle passage 122 and a further stop shoulder 118 ', which cooperates with the further counter stop shoulder 120 on the sleeve 58.

Fig. 6 shows a further training possibility of the injection valve member 22, namely, the control piston 60 and the shaft 48 are formed as individual parts. The connection between these parts can be done for example by means of a press fit, by a close fit or by welding. The shaft 48 may also penetrate the control piston 60. In this case, the projection 80 is formed from the upper end of the shaft 48, and the control piston 60 is a sleeve with a through hole, which can be assembled with the shaft 48 as mentioned above.

The functioning of the in the Fig. 6 shown embodiment of the control device 26 is the same as that according to Fig. 5 ,

The in the Fig. 7 . 8a and 8b embodiment shown also comprises a tubular housing 12, in which the control body 72 is arranged tightly. With its end facing the control chamber 62, the sleeve 58, in which the double-acting control piston 60 of the injection valve member 22 is movably disposed in a close fit in the axial direction, now sealingly and without hydraulic connection to the high pressure chamber 20. As described above relies on the sleeve 58, on the side facing away from the control body 72, the closing spring 46 for the injection valve member 22 from. The control chamber 62 is thus bounded on the one hand by the control piston 60, peripherally by the sleeve 58 and on the other hand by the control body 72.

The control body 72 has, concentrically and in the direction of the axis 24, the control passage 82, into which the throttle inlet 92 running in the radial direction opens. This is due to an external milling 128 and the flow gap 88 between the sleeve 58 and the housing 12 connected to the high-pressure chamber 20. From the control chamber 62 facing the end face of the control body 72 extends through this to the throttle inlet 92 a bore 130. This opens into the throttle inlet 92 on the relative to the narrowest flow cross-section of the high-pressure chamber 20 side facing.

Both the control room-side mouth of the control passage 82 and those of the bore 130 are covered by a leaf spring-like tongue 132, whose shape from the Fig. 8a and 8b is recognizable. At the end facing away from the bore 130, the tongue 132 is welded to the control body 72. The weld is designated 134. The tongue 132 has a throttle passage 74 coaxial with the axis 24, which connects the control chamber 62 with the control passage 82. Again, the throttle restriction 82 'in the control passage 82 cross-sectional larger than the narrowest cross section of the throttle inlet 92 and the cross section of the throttle passage 74. The narrowest cross section 82' of the control passage 82 is connected on the outlet side with a bore 83 of slightly larger cross-section. The bore 83 is preferably relatively long, as compared to the diameter, at least 2 to 10 times as long. Thus, the flow after the narrowest cross-section 82 'again fill the full, larger cross section 83, which favors the flow through the narrowest cross section 82'. Moreover, the fuel injection valve is the same as in the Fig. 1 to 4 shown.

The control device 26 according to Fig. 7 . 8a and 8b works as follows. For the description of the operation of the fuel injection valve 10 with a control device 26 according to the Fig. 7 . 8a and 8b becomes, as in connection with the embodiments described above, starting from the idle state in which the injection valve member 22 is in the closed position and the pressure in the control chamber 62 corresponds to the pressure in the high-pressure chamber 20. The pilot valve 104 is closed by abutment of the valve pin 98 on the control body 72.

Upon excitation of the electromagnet 100 (see. Fig. 2 ), the valve pin 98 is lifted off the control body 72 as a result of the pending in the control passage 82 high pressure. The control passage 82 is thereby connected to the low pressure space 106 (see FIG Fig. 2 ) connected. The pressure in the control passage 82 decreases, whereby due to the pressure difference fuel flows through the throttle passage 74 from the control chamber 62 into the control passage 82. Once the pressure in the control chamber 62 has dropped so far that the negative pressure with respect to the pressure in the high-pressure chamber 20 is sufficient to overcome the force of the closing spring 46, the injection valve member 22 moves away from the valve seat 44, whereby the injection process begins. When de-energizing the solenoid 100, the valve pin 98 engages the control body 72 again, whereby the control passage 82 is separated from the low-pressure chamber. On the side of the tongue 32 facing away from the control chamber 62, the pressure in the control passage 82 increases, which leads to bending of the tongue 132 as a result of the widening of the control passage and the pressure in the bore 130. As a result of the release of the control passage 82 and the bore 130 now passes fuel over a larger flow cross-section in the control chamber 62, which leads to a rapid pressure increase in the control chamber 62 and for faster movement of the injection valve member 22 to the valve seat 44. By dimensioning the corresponding passages and the properties of the tongue 132, the Operating behavior of the fuel injection valve to be designed according to the requirements.

In the embodiment according to Fig. 7 . Fig. 8a and Fig. 8b touches the end face of the control piston 60 at the end of the opening process of the injection valve member 22, the underside of the leaf spring-like tongue 132, and holds it pressed against the underside of the control body 72. An unintentional, uncontrolled opening of the tongue 132 and consequently the bore 130 with the fuel injection valve 10 fully open is thus avoided. This solution is analogous in this respect to the solution of Fig. 1 to 4 in which the slide valve 66 is kept pressed by the projection 80. Also in the training according to Fig. 7 to 8b For example, the end face of the control piston 60 - or a protrusion thereof - may be designed such that at the end of the opening stroke the throttle passage 74 is closed, and the pressure in the control chamber 62 is not or not fully equalized to the lowest pressure in the control passage 82.

On the other hand, the control piston 60, analogous to in Fig. 5 shown, a circumferential bead which cooperates with its stop shoulder and a counter-stop shoulder to limit the stroke of the injection valve member 22 before the end face of the control piston 60 contacts the underside of the tongue 132.

The Fig. 9a and 9b show in the same representation as the Fig. 8a and 8b a section VIII-VIII according to Fig. 7 and the tongue 132 in a different embodiment. The tongue 132 is integrally formed on a retaining ring 136. The retaining ring 136 is at least at one, preferably at several points, for example at the welding points designated 134, the control body 72nd welded. The leaf spring element according to Fig. 9b can be produced in a simple manner by punching a C-shaped groove out of a circular spring steel disk. The operation of the fuel injection valve 10 with a control device 26 according to Fig. 7 but with an embodiment of the tongue 132 according to FIGS Fig. 9a and 9b , is the same as the one above Fig. 7 . 8a and 8b described.

As in particular from the Fig. 10 in conjunction with the Fig. 2 and 3a shows, the solenoid assembly 16 has a housing sleeve 138 with an integrally formed on the inside circumferential ring 140. The ring 140 defines a contact surface 142, with which it rests in the mounted state on a flat outer surface 144 of the further union nut 94. As a result, the axial position of the electromagnet assembly 16 is defined. A projecting in the axial direction over the contact surface 142 portion 143 of the housing sleeve 138 surrounds the further union nut 94, whereby the radial position of the electromagnet assembly 16 is defined. An O-ring 146 seals the low pressure space 106 from the environment. To the further union nut 94 extends around a threaded ring 148 which is supported on the one hand on a circumferential shoulder 149 of the further union nut 94 and on the other hand screwed with its internal thread 149 'with an external thread 143' on the housing sleeve 138.

On the ring 140 sits on the side facing away from the contact surface 142 an annular magnetic circuit plate 150. At this is supported in the axial direction, also designed as a ring body magnetic body 152 from which on the magnetic circuit plate 150th facing side has a circumferential axis 124 around the annular groove 154. In this is the coil 155, which via electrical coil connecting conductor 156 - in the Fig. 10 only one is shown - connected to an electrical control device. On the magnetic circuit board 150 side facing away from the magnetic body 152 is a holding body 158, which may consist of a non-magnetic material. In a circumferentially arranged circumferential groove of the holding body 158, a further O-ring 160 is inserted, which rests against the inside of the housing sleeve 138 and correspondingly sealing off the low-pressure chamber 106 from the environment. The this side end portion of the housing sleeve 138 is bent in the direction against the inside (possibly flared) and abuts against a frustoconical lateral surface portion of the holding body 158. As a result, the magnetic circuit plate 150, the magnetic body 152 and the holding body 158 are held firmly in the housing sleeve 138.

The holding body 158 protrudes in the axial direction with a stub 164 on the housing sleeve 138. In the stub 164 of the low-pressure connection stub 110 is eingindet.

The armature 102 has an anchor ring 168, which is welded to an armature shaft 166 and is arranged inside the magnetic circuit plate 150 in the radial direction, forming a narrow air gap. The armature shaft 166 is guided in a stop sleeve 170, which is supported on the magnetic body 152 in the axial direction on a support shoulder 172. The stop sleeve 170 is welded or crimped to the magnetic body 152 at 174 as shown. The stop sleeve 170 forms an axial stop for an annular shoulder 176 and 16 formed on the armature shaft 166 ensures that between the anchor ring 168 and the magnetic body 152, a gap remains free when the armature 102 is attracted by the electromagnet 100. Adjacent to the radially inner end of the magnetic circuit plate 150, this has on the side facing the magnetic body 152 a circumferential recess 178 which is connected via axially extending communication holes 180 through the magnetic circuit board 150 through always with the low-pressure chamber 106. This allows a very rapid pressure equalization between the two sides of the anchor ring 168 during the movement of the armature 102.

The armature 102 has an over the anchor ring 168 in the axial direction against the valve pin 98 projecting nose 182, which is intended to interact with the valve pin 98 together. The nose 182 has a transverse bore 184, which opens into a blind hole 186 in the armature shaft 166. The armature shaft 166 protrudes on the side facing away from the nose 182 with an end region in the axial direction via the stop sleeve 170. There, a suppository 190 is inserted into the armature shaft 166, on which on the other hand, the armature spring 112 is supported. Further transverse bores 184 'in the armature shaft 166 connect the blind bore 186 adjacent to the suppository 190 with a arranged in the holding body 158 space 192 which is fluidly connected to the Niederdruckauslassstutzen 110 and in which the armature spring 112 is supported on the holding body 158. The connecting channel 108 formed by the blind bore 186, the transverse bores 184, 184 'and the space 192 connects the low-pressure chamber 106 with the low-pressure connecting piece 110.

In the in the Fig. 2 and 10 the solenoid 100 is not energized, whereby the valve pin 98th held in contact with the control body 72 due to the force exerted by the armature spring 112 force. When the solenoid 100 is energized, the armature ring 168 is tightened together with the armature shaft 166, reducing the gap between the armature ring 168 and the magnetic body 152, causing the valve pin 98 to move away from the control body 72 in the axial direction, resulting in a Injection process leads. When the solenoid is de-energized, the armature 102 is moved in the opposite direction by the force of the armature spring 112, causing the valve pin 98 to close the throttle passage in the control body 72, thereby completing the injection process.

Due to the armature springs 112 subjected to scattering, it is necessary to calibrate the solenoid assembly 16 to achieve highly accurate injections. This is done by selecting a suitable suppository 190. For this purpose suppositories 190 are provided with different axial spacing of the surfaces with which the suppositories rest on the one hand on the armature shaft 166 and on the other hand on the armature spring 112. The contact surface 142 serves as the basis for the measuring device. In order to ensure easy replacement of the suppositories 190 during the calibration process, preferably both the largest outer diameter of the suppository 190 and the outer diameter of the spring 112 are smaller than the guide diameter of the armature shaft 166 in the stop sleeve 170.

The length of the valve pin 98 can also be selected as a function of the stroke that the armature 102 is intended to cover. The outer surface 144 serves as a basis for the measurement of the distance between this surface and the control body 72nd

The different embodiments of the inventive fuel injection valve 10 have a slim design and offer a number of ways to adapt the properties of the desired course of the injection process.

The control devices 26 according to the invention can also be used in otherwise differently constructed fuel injection valves; as well as in fuel injection valves, in which the fuel via a separate channel, and not coaxial with or on the axis 24 of the injector but laterally thereof, is supplied to the valve seat member in the housing.

The illustrated and described solenoid assembly and its attachment to the housing of the fuel injection valve can be used in different fuel injection valves.

The tubular housing may also have differently shaped, generally known means for securing an electromagnet arrangement instead of a thread.

A tubular housing with mounting options on the one hand for a valve seat member and on the other hand, a solenoid assembly and a connection sleeve with high-pressure connection piece can also be used in differently designed fuel injectors.

An injection valve member, as described above, in which the stem and the control piston are manufactured as individual parts, can be used in any fuel injection valves.

Claims (6)

1. Fuel injection valve for intermittently injecting fuel into the combustion chamber of an internal combustion engine, having a housing (12) which has a high-pressure inlet (18) for the fuel, having an injection valve member (22) which is designed for interacting with a valve seat element (14) and is arranged in a longitudinally movable manner in the housing (12) and is springloaded in the direction of the valve seat element (14), having a double-acting control piston (60) which is arranged on the injection valve member (22) and which at one side delimits a high-pressure chamber (20) flow-connected to the high-pressure inlet (18) and at the other side delimits a control chamber (62), having a control body (72) which likewise delimits the control chamber (62) and has a control passage (82) which proceeds from the control chamber (62) and is connected via a throttle inlet (92) to the high-pressure chamber (20) and can be connected by means of a pilot valve (104) to a low-pressure chamber (106), having an inflow duct (130) which connects the high-pressure chamber (20) to the control chamber (62) and has a separate aperture opening, and having a valve member which, in a closed position, closes off the inflow duct (130) and the control passage (82), which valve member has a throttle passage (74) which connects the control chamber (62) to the control passage (82), characterized in that the valve member is designed as a leafspring-like tongue (132) which is fastened at one end.
2. Fuel injection valve according to Claim 1, characterized in that the tongue is fastened to the control body (72) and bears against the latter in the rest state.
3. Fuel injection valve according to Claim 1 or 2, characterized in that the tongue (132) is integrally formed on a retaining ring (136) which surrounds it.
4. Fuel injection valve according to one of Claims 1 to 3, characterized in that the tongue (132) or the retaining ring (136) is welded to the control body (72).
5. Fuel injection valve according to one of Claims 1 to 4, characterized in that the injection valve member (22) extends through a closing spring (46) designed as a coil spring, which closing spring (46) is supported at one side on a first ring (54) which engages around half support flanges (52) seated on the injection valve member (22), and which closing spring (46) is supported at the other side by means of a single-piece second ring (54') which has a slot, is supported fixedly with respect to the housing and encompasses the injection valve member (22).
6. Fuel injection valve according to one of Claims 1 to 5, characterized in that the pilot valve (104) is actuated by means of an electromagnet arrangement (16) arranged in a housing sleeve (138), and the housing sleeve (138) has a contact surface (142) by means of which said housing sleeve (138), in the assembled state, bears against an outer surface (144) which is fixed with respect to the housing.

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