DE10113008A1 - Solenoid valve for controlling an injection valve of an internal combustion engine - Google Patents

Abstract

The invention relates to an electromagnetic valve for controlling an injection valve of an internal combustion engine, comprising an electromagnet (29), a moving armature with an armature plate (28) and an armature pin (27); and a control valve member (25) which is moved with the armature and which interacts with a valve seat (24), for opening and closing a fuel drainage channel (17) of a control pressure chamber (14) of the injection valve (1). The armature plate (28) is mounted in such a way that under the influence of its inert mass, the armature plate can slide on the armature pin in the closing direction of the control valve member (25), in the opposite direction to the clamping force of a return spring (35) which acts on the armature plate. The inventive electromagnetic valve also comprises a hydraulic damping device with which the post-oscillation of the armature plate (28) after its dynamic displacement on the armature pin (27) can be damped. In order to simplify the assembly and reduce a disadvantageous post-oscillation process of the armature plate, the invention provides that the return spring (35) is supported on a support part (50) which is situated on the armature pin (27) and which is moved with said armature pin, by the end (62) of the return spring facing away from the armature plate (28). Said support part (50) also forms part (57) of the damping device.

Description

State of the art

The invention relates to a solenoid valve for controlling a Injection valve of an internal combustion engine according to the Oberbe handle of claim 1.

Such a, for example from DE 197 08 104 A1 The solenoid valve is used to control the fuel pressure in the Control pressure chamber of an injection valve, for example one Injector of a common rail injection system used. about the fuel pressure in the control pressure chamber becomes the movement nes valve piston controlled with an injection opening of the injection valve is opened or closed. That be Known solenoid valve has one in a housing part arranged electromagnets, a movable armature and a moved with the anchor, by a closing spring in closing direction acted upon control valve member with a Valve seat of the solenoid valve interacts and so the force controls outflow of material from the control pressure chamber. A friend The disadvantage of the solenoid valves is the so-called armature bounce len. When the magnet is switched off, the armature becomes and with it the control valve member from the closing spring of the solenoid valve accelerated toward the valve seat to fuel drain  to close the duct from the control pressure chamber. The impact the control valve member on the valve seat can be a disadvantage Swinging and / or bouncing of the control valve member on the Ven tilsitz resulting in the control of the input Spraying is affected.

In the solenoid valve known from DE 197 08 104 A1 therefore the anchor in two parts with an anchor bolt and one anchor plate slidably mounted on the anchor bolt executed so that the anchor plate when the Control valve member on the valve seat against the clamping force a return spring moved. The return spring is conveyed the anchor plate then back to its starting position at a stop on the anchor bolt. Through the two partial execution of the anchor is actually the abge braked mass and thus the kine causing the bouncing table energy of the armature hitting the valve seat reduced, however, the anchor plate after closing of the solenoid valve on the anchor bolt disadvantageously reverberate. Since a control of the solenoid valve only like which leads to a defined injection quantity if the An measures no longer swing Lich to reduce the reverberation of the anchor plate. This is particularly useful for displaying short time intervals would be between, for example, a pre and main injection required.

DE 197 08 104 A1 proposes to solve this problem beaten to use an overstroke stop, which the Path length limited by which the anchor plate on the An notch bolt can move. The overstroke is between the anchor plate and a slide guiding the anchor bolt piece arranged in the housing of the solenoid valve. at an approach of the anchor plate to the overstroke ent stands between the facing flat sides of the  Anchor plate and the overstroke stop a hydraulic damper fung space. The fuel contained in the damping chamber generates a force that counteracts the movement of the anchor plate counteracts. The reverberation of the anchor plate is therefore strong attenuated. By means of the overstroke stop, the after vibration time of the anchor plate is shortened, but the required Over travel of the anchor plate during the assembly of the Solenoid valve set in the housing of the solenoid valve the. This makes an expensive change in manufacturing procedure required, since the manufacturing facilities ent need to be retrofitted accordingly.

Advantages of the invention

The solenoid valve according to the invention with the characteristic Features of claim 1 avoids that in the prior art disadvantages. The anchor can be advantageous with An anchor plate, anchor bolt, return spring and overstroke stop au Pre-assembled outside the injection valve assembly line and the required displacement of the anchor plate on the Anchor bolt outside the injector housing be put. The pre-assembled armature assembly can then then installed in the housing of the solenoid valve the. A complex conversion of the assembly line is not necessary sary. The fact that the return spring, which the An Kerplatte with a first end in its rest position against egg presses a first stop on the anchor bolt with which does not support the second end in the solenoid valve housing, but on one fixed to the anchor bolt and with the Anchor bolt moving support part will also be advantageous achieved that the return spring of the on the anchor bolt acting against the closing spring of the solenoid valve acts. The spring tension of the magnetic valve's closing spring tils can therefore be designed lower. Because the return who no longer counteracts the closing spring has the back  holfeder no longer has any influence on the dynamic behavior of the anchor bolt.

Advantageous exemplary embodiments and developments of Invention are contained in the subclaims features.

It is particularly advantageous to anchor the anchor bolt in an opening voltage in the housing of the solenoid valve arranged slidably to slide and the Anchor plate facing side of the slider with an off Take to provide in which the firmly attached to the anchor bolt placed support part is arranged, the outer contour of the Support part through a gap from the inner contour of the Ausneh mung is spaced. Through these measures it is achieved that by the approach of the support member to the inner wall of the Recess of the slide a hydraulic damping space arises and that between the support part and the recess compressed fuel the impact of the with the anchor bolt coupled control valve member on the valve seat additional dampens.

drawings

Embodiments of the invention are in the drawings are shown and are described in the following description purifies. It shows

Fig. 1 shows a cross section through the upper part of a known prior art fuel injector with a solenoid valve,

Fig. 2 shows a portion of the BE of the prior art known solenoid valve with overtravel setting disc,

Fig. 3 shows a cross section through the armature assembly with sliding piece according to a first embodiment of the invention,

Fig. 4 shows a cross section through the armature assembly with sliding piece according to a second embodiment of the invention,

Fig. 5 shows a cross section through the armature assembly with sliding piece according to a third embodiment of the invention.

Description of the embodiments

Fig. 1 shows the upper part of a known from the prior art fuel injection valve 1, which is intended for use in a fuel injection system that is equipped with a fuel high-pressure accumulator, which is supplied by a high-pressure feed pump continuously with high pressure fuel. The fuel injector 1 shown has a valve housing 4 with a longitudinal bore 5 , in which a valve piston 6 is arranged, which acts with its one end on a valve needle arranged in a nozzle body, not shown. The valve needle is arranged in a pressure chamber which is supplied with fuel under high pressure via a pressure bore 8 . During an opening stroke movement of the valve piston 6 , the valve needle is raised by the constant digging force acting on a pressure shoulder of the valve needle force high pressure in the pressure chamber against the closing force of a spring. The fuel is then injected into the combustion chamber of the internal combustion engine through an injection opening which is then connected to the pressure chamber. By lowering the Ven tilkolbens 6 , the valve needle is pressed in the closing direction in the valve seat of the injection valve and the injection process ends.

As can be seen in Fig. 1, the valve piston 6 is at its end facing away from the valve needle in a Zylin derbohrung 11 , which is inserted in a valve piece 12 which is inserted into the valve housing 4 . In the cylinder bore 11 , the end face 13 of the valve piston 6 includes a control pressure chamber 14 which is connected to a high-pressure fuel connection via an inlet channel. The inlet channel is formed in three parts. A radially through the wall of the valve member 12 leading bore, the inner walls of which form part of their length an inlet throttle 15 , is constantly connected to an annular space 16 surrounding the valve piece, the annular space in turn via a fuel filter inserted into the inlet channel in constant Connected to the high-pressure fuel connection of a connecting piece 9 which can be screwed into the valve housing 4 . The annular space 16 is sealed off from the longitudinal bore 5 by a sealing ring 39 . The control pressure chamber 14 is exposed to the high fuel pressure prevailing in the high-pressure fuel reservoir via the inlet throttle 15 . Coaxially to the valve piston 6 branches off from the control pressure chamber 14 from a running in the valve piece 12 tion, which forms a provided with an outlet throttle 18 fuel outlet channel 17 , which opens into a relief chamber 19 , which is connected to a fuel low pressure connection 10 , which in turn is not in further shown is connected to a fuel return of an injection valve 1 . The exit of the fuel drainage channel 17 from the valve piece 12 takes place in the loading area of a conically countersunk part 21 of the outer end face of the valve piece 12 . The valve piece 12 is firmly clamped to the valve housing 4 in a flange region 22 by means of a screw member 23 .

In the conical part 21 , a valve seat 24 is ausgebil det, with which a control valve member 25 of a solenoid valve 30 which controls the injection valve cooperates. The control valve member 25 is coupled to a two-part armature in the form of an anchor bolt 27 and an anchor plate 28 , which armature interacts with an electromagnet 29 of the solenoid valve 30 . The solenoid valve 30 further comprises a housing part 60 which accommodates the electromagnet and which is firmly connected to the valve housing 4 via screwable connecting means 7 . In the known solenoid valve, the anchor plate 28 is dynamically displaceably mounted on the anchor bolt 27 under the action of its inert mass against the pre-tensioning force of a return spring 35 and is pressed by this return means which, in the idle state, is pressed against a disk 26 fixed on the anchor bolt. With its other end, the return spring 35 is fixed to the housing on a flange 32 of an anchor bolt 27 leading slide 34 which is clamped with the flange between a spacer 38 placed on the valve piece 12 and the screw member 23 in the valve housing. The anchor bolt with 27 him the armature disc 28 and coupled to the anchor bolt control valve member 25 are constantly beat, so that the control valve member 25 normally rests by itself fixed to the housing supporting the closing spring 31 in the closing direction beauf in the closed position on the valve seat 24th When the electromagnet is excited, the armature plate 28 is attracted by the electromagnet and the drain channel 17 is opened towards the relief chamber 19 . Between the control valve member 25 and the armature plate 28 there is an annular shoulder 33 on the armature bolt 27 which strikes the flange 32 when the electromagnet is excited and thus limits the opening stroke of the control valve member 25 . To set the opening stroke between the flange's 32 and the valve piece 12 arranged Di punch plate 38th In other known solenoid valves, the opening stroke of the control valve member 25 is set by a rule between the armature plate 28 and the electromagnet 29 angeord net stop element.

The opening and closing of the injection valve is controlled by the solenoid valve 30 as described below. The anchor bolt 27 is constantly urged by the closing spring 31 in the closing direction, so that the control valve member 25 abuts when the electromagnet is not excited in the closed position on the valve seat 24 and the control pressure chamber 14 to Entla stungsseite 19 towards is closed so that there very quickly via the inlet channel of the builds up high pressure, which is also present in the high-pressure fuel accumulator. Over the surface of the end face 13 , the pressure in the control pressure chamber 14 generates a closing force on the valve piston 6 and the valve needle connected therewith which is greater than the forces acting on the other hand in the opening direction as a result of the high pressure present. If the control pressure chamber 14 is opened by opening the solenoid valve towards the relief side 19 , the pressure in the small volume of the control pressure chamber 14 builds up very quickly, since it is decoupled from the high pressure side via the inlet throttle 15 . In consequence, the force acting on the valve needle in the opening direction outweighs the high fuel pressure pending on the valve needle, so that the valve needle moves upward and the at least one injection opening is opened for injection. However, if the solenoid valve 30 closes the fuel outlet channel 17 , the pressure in the control pressure chamber 14 can be re-built up by the fuel flowing through the inlet channel 15 , so that the original closing force is present and the valve needle of the fuel injection valve closes.

When the solenoid valve closes, the closing spring 31 suddenly presses the anchor bolt 27 with the control valve member 25 against the valve seat 24 . A disadvantageous bouncing or reverberation of the control valve member arises in that the impact of the anchor bolt on the valve seat causes an elastic deformation thereof, which acts as an energy store, with part of the energy in turn being transferred to the control valve member, which then together with the Ankerbol zen from the valve seat 24 bounces off. The known solenoid valve shown in FIG. 1 therefore uses a two-part armature with an anchor plate 28 decoupled from the anchor bolt 27 .

In this way, it is possible to reduce the total mass impinging on the valve seat, but the anchor plate 28 can oscillate in a disadvantageous manner. For this reason, in the known solenoid valve arranged between the anchor plate 28 and the sliding sleeve 34 Überhubein adjusting disk 70 is provided, as shown in Fig. 2. The overtravel 70 limits the displacement away from the anchor plate 28 on the anchor bolt 27 to the dimension d. The reverberation of the anchor plate 28 is reduced by the over-stroke adjusting disk 70 and the anchor plate 28 returns to its initial position at the stop 26 more quickly. The spacer 38 , the slider 34 and the Überhubein adjusting disk 70 are clamped in place in the solenoid valve housing. The overtravel distance d must therefore be set in the solenoid valves known in the prior art during assembly in the solenoid valve housing over the thickness of the related overtravel adjustment disc. In some embodiments, the thickness of the overtravel adjusting disk also influences the distance of the armature plate 28 from the electromagnet 29 . This is the case if, for example, the end face of the magnetic valve housing 60 is clamped against the flange 32 . In these cases, an inner and an outer disc are used instead of the overtravel adjusting disc. The manufacture of the solenoid valve and the injection valve provided with the solenoid valve is therefore quite complex and complicated. A pre-setting of the overtravel or the displacement d of the armature plate 28 on the armature bolt 27 outside of the magnetic valve housing 60 is not possible.

Fig. 3 shows a first embodiment of the solenoid valve according to the invention. Shown is only the slider 34 and the anchor with anchor bolt 27 , anchor plate 28 and return spring 35th The same parts are seen with the same reference numerals. The armature assembly shown can be used, for example, in the solenoid valve housing 60 shown in FIG. 1. An important difference from the arrangement shown in Fig. 2 be known is that a support member 50 is provided in place of the fixed in the solenoid valve over-stroke adjusting disc, which is fixedly connected to the anchor bolt 27 . For example, a disk fixed to the anchor bolt 27 can be provided as the supporting part. In the embodiment of FIG. 3, the washer is pushed onto the anchor bolt 27 and then bolted to the anchor by, for example, welding or gluing. Other types of fastening such as shrinking on are also possible. In a preferred embodiment, the support part 50 is welded to the anchor bolt 27 on the side 59 facing away from the anchor plate. The weld seam 51 on the underside 59 of the support part 50 can be seen in FIG. 1. The return spring 35 is supported with its one end 61 on the anchor plate 28 and with its other end 62 on the side 57 of the supporting part 50 which faces the anchor plate 28 .

In the manufacture of the armature assembly, the anchor plate 28 is first pushed onto the anchor bolt 27 until the anchor plate strikes a head 55 of the anchor bolt. The head 55 replaces the sickle disk 26 in FIGS. 1 and 2 and, like this, serves as a stop for the anchor plate. Subsequently, the return spring 35 is pushed over the guide stub 65 of the anchor plate 28 until it rests with the end 61 on the kerplatte. Finally, the disk-shaped support member 50 is pushed so far onto the anchor bolt 27 that the required overtravel distance d remains between the mutually facing sides 57 and 58 of the support member 50 and the guide stub 65 . Finally, the support part 50 is fixed in this position on the anchor bolt 27 . The existing from anchor bolt 27 , anchor plate 28 , return spring 35 and support member 50 anchor assembly is then inserted into the slider 34 . The anchor bolt 27 is inserted into a central bore 68 of the slider 34 . The slider 34 can already be clamped with the flange 36 in the housing 60 of the solenoid valve. As can also be seen in FIG. 3, deviating from the known arrangement shown in FIG. 2, no annular shoulder 33 is provided, which limits the opening stroke of the anchor bolt by a stop on the slide piece 34 . Instead, the opening stroke is limited by a stop of the armature bolt head 55 on the electromagnet or a projection of the electromagnet. This is necessary so that the anchor bolt 27 in FIG. 3 can be inserted into the slider 34 from above. As can also be seen in FIG. 3, the side of the sliding piece 34 facing the supporting part 50 has a recess 52 into which the supporting part engages.

As already described in detail above, the lower end 67 of the armature pin 27 acts on the control valve member 25 in a built state, which is pressed against the valve seat 24 by the closing force of the spring 31 when the electromagnet is not energized. In this position, the side 59 of the support part 50 facing away from the anchor plate 28 and the weld seam 51 are spaced apart from the inner wall of the recess 52 by a gap. By this measure, when the solenoid valve is closed, the abutment of the support part 50 moved with the anchor bolt on the inner wall of the recess 52 is prevented, since such abutment could result in the control valve member 25 on the valve seat 24 not reaching the system. The recess 52 is therefore designed in such a way that it can also accommodate the weld seam 51 and is always at a distance from it.

As can also be seen in Fig. 3, is created by the approach of the bottom 59 of the support member 50 to the inner wall of the cylindrical recess 52 of the slider 34 when closing the solenoid valve, a hydraulic damping space.

The fuel compressed between the support member 50 and the recess 52 , which can only escape laterally through the gap, advantageously dampens the impact of the anchor bolt 27 and the control valve member 25 coupled thereto on the valve seat 24 .

As soon as the anchor bolt 27 and the control valve member 25 have come to rest on the valve seat 24 , the Ankerplat te 28 slides due to its inert mass against the resilience of the return spring 35 on the anchor bolt down. Between the support member 50 facing toward lower face 58 of the armature plate 28 and the anchor plate 28 facing side 57 of the not moving at that moment, the support member 50 is formed due to the approach of the armature plate 28 of a further hydraulic damping chamber. The ent held in the gap between the anchor plate 28 and the support member 50 brings a counterforce, which counteracts the loading movement of the anchor plate. The compensatory movement of the armature plate 28 is therefore limited by the position of the support part on the anchor bolt 27 , which leads to a movement reversal after previous damping and thus leads to a reduction in the ringing process.

FIG. 4 shows a further exemplary embodiment of the invention, which differs from the exemplary embodiment shown in FIG. 3 in that the supporting part 50 is positively fixed on the anchor bolt 27 . The support member 50 is formed in this embodiment as a sickle disk with an open NEN recess 56 which is pushed laterally with the open end onto the anchor bolt. The Ankerbol zen 27 has a circumferential groove 54 , in which the inner contour of the recess 56 of the sickle plate 50 engages in a form-fitting manner. The on the anchor bolt pushed sickle be 50 is secured perpendicular to the anchor bolt through the recess 52 of the slider 34 in position. The path length by which the anchor bolt is moved in the axial direction when opening and closing the Magnetven valve is significantly smaller than the depth of the recess 52 , so that the sickle disk 50 cannot accidentally slip out of its position on the anchor bolt 27 .

FIG. 5 shows a third exemplary embodiment, which shows a modification of the exemplary embodiment illustrated in FIG. 4. In this embodiment, the support member 50 is again formed as a sickle disc, which is pushed with the open end, not shown, onto a section 72 of the anchor bolt 27 . The diameter of the section 72 is made smaller than the diameter of the section of the anchor bolt 27 guided in the sliding piece 34 and delimited by a circumferential shoulder 71 thereof. The return spring 35 is supported at one end on the anchor plate 28 . With the other end, the return spring 35 presses the sickle disk 50 against the circumferential shoulder 71 formed on the anchor bolt 27 . The armature assembly can be used as a pre-assembled unit in the slider 34 , where the anchor bolt 27 is inserted into the opening 68 and the sickle plate 50 at least partially penetrates into the recess 52 . By the inner contour of the recess 52, the sickle-shaped disc is secured kerbolzen against lateral slipping of the on 50th

Claims (10)

A solenoid valve for controlling an injection valve of an internal combustion engine, comprising an electromagnet ( 29 ), a movable armature with an armature plate ( 28 ) and armature bolt ( 27 ) and a control valve member ( 25 ) which is moved with the armature and cooperates with a valve seat ( 24 ) and which opens and closing a fuel discharge channel (17) of a control pressure chamber (14) of the injection valve (1), which armature plate (28) under the action of its inert mass in the closing direction of the control valve member (25) against the biasing force of a force acting on the armature plate (28) return spring (35 ) is slidably mounted on the anchor bolt ( 27 ), and with a hydraulic damping device with which a swinging of the anchor plate ( 28 ) can be damped when it is dynamically displaced on the anchor bolt ( 27 ), characterized in that the return spring ( 35 ) with its end ( 62 ) facing away from the anchor plate ( 28 ) at an end on the A Support bolt ( 27 ) arranged and with the anchor bolt moving th supporting part ( 50 ) is supported, which supporting part ( 50 ) also forms part ( 57 ) of the damping device. 2. Solenoid valve according to claim 1, characterized in that the armature bolt ( 27 ), the armature plate ( 28 ), the return spring ( 35 ) and the support member ( 50 ) fixed to the armature bolt are inserted as a preassembled armature assembly in the solenoid valve housing ( 60 ). 3. Solenoid valve according to claim 1 or 2, characterized in that the anchor bolt ( 27 ) in an opening ( 68 ) of a in the housing ( 60 ) of the solenoid valve ( 30 ) fixedly arranged th slide ( 34 ) is slidably mounted. 4. Solenoid valve according to claim 3, characterized in that the armature plate ( 28 ) facing side of the slider ( 34 ) has a recess ( 52 ) in which the bolt on the armature ( 27 ) arranged support member ( 50 ) is arranged, wherein the outer contour of the support part ( 50 ) is spaced from the inner contour of the recess ( 52 ) by a gap. 5. Solenoid valve according to claim 4, characterized in that the fuel-filled gap between the support part ( 50 ) and the inner wall of the recess ( 52 ) forms a further damping device by means of which the control valve member ( 25 ) coupled to the anchor bolt ( 27 ) strikes ) can be damped on the valve seat ( 24 ). 6. Solenoid valve according to one of claims 1 to 5, characterized in that the supporting part ( 50 ) is disc-shaped. 7. Solenoid valve according to one of claims 1 to 6, characterized in that the supporting part ( 50 ) by welding, gluing, soldering or shrinking on the anchor bolt ( 27 ) is fixed. 8. Solenoid valve according to one of claims 1 to 5, characterized in that the supporting part ( 50 ) is designed as a sickle disk. 9. Solenoid valve according to claim 8, characterized in that the supporting part is positively fixed in a circumferential groove ( 54 ) of the anchor bolt ( 27 ). 10. Solenoid valve according to claim 4 and 8, characterized in that the sickle disc ( 50 ) is pushed laterally onto a section ( 72 ) of the anchor bolt ( 27 ) which is not guided in the slide ( 34 ) and is spring-loaded by the spring force of the return spring ( 35 ) is pressed against a shoulder ( 71 ) formed on the anchor bolt ( 27 ) and is secured in the radial direction against slipping off the anchor bolt by the inner contour of the recess ( 52 ).