Title of Invention

FUEL INJECTION DEVICE FOR INTERNAL COMBUSSTION ENGINES

Abstract

Fuel injection device for internal combustion engines Abstract A fuel injection device for internal combustion engines is proposed, in which a fuel injection valve has a tappet (21) which is to be actuated by an injection valve member, and which delimits a control space (25) which is supplied constantly with high-pressure fuel via a throttle (27) and which can be relieved via a control valve (36) and an outflow duct (129). For this purpose, the control valve (36) has a valve member (44) which is actuated by a piezoelectric device (35) in such a way that, during the opening of the outflow duct (129) , the valve member is moved towards the control space (25) . In the closed position, the valve member (44) is subjected to the pressure in the control space (125) in the closing direction. (Figure 2)

Full Text

R. 30421 05.06.96 Bo/Ru ROBERT BOSCH GMBH, 70442 Stuttgart Fuel injection device for internal combustion engines Prior art The invention proceeds from a fuel injection device for internal combustion engines according to the pre-characterizing clause of Patent Claim 1. In a fuel injection device of this type, known from 6B Patent Specification 1,320,057, the outflow duct coming from the control space opens into a collecting space which is connected, via a relief conduit leading further, to a relief space. The valve seat for the valve member of the control valve is provided at the entry of the outflow duct into this collecting space. The said valve member has a piezoelectric device as a drive and is designed as a valve member with a conical sealing surface. This valve performs the function of controlling the pressure in the control space, account being taken of the fact that, so that a piezoelectric device can work in an operationally reliable manner, it should be subjected only to pressure. In view of this, in the closed position, the piezoelectric device has acting on it the closing force transmitted by the valve seat and the resultant force which is exerted on the valve member over the cross-section of the outflow duct as a consequence of the pressure load. In this case, some of the working capacity of the piezoelectric device is wasted in the provision of the closing force. Advantages of the invention In contrast to this, the advantage of the fuel injection device according to the invention, having the characterizing features of Patent Claim 1, is that the closing force necessary for sealingly closing the control valve does not need to be applied by the piezoelectric device, but is generated by the pressure in the control space. A high actuating force to be applied by the piezoelectric device is necessary only for opening the valve, here again the piezoelectric device being sub¬jected to the set pressure in the control space. As soon as the valve has opened, the force counteracting the actuating movement of or the opening of the control valve is rapidly reduced, so that, in this case too, the piezoelectric device does not undergo any appreciable load. Thus, in the design according to the invention, the piezoelectric device actuating the control valve can be made substantially smaller and the necessary energy kept lower. When the valve member is in the closed position, it performs a self-sealing function due to the fact that, in this position, the high fuel pressure supplied via the inflow always prevails in the control space. In an advantageous development according to Patent Claim 2, the space necessary for the actuating movement of the valve member in the opening direction is reduced to the region of a recess, so that the diameter of the control piston can be kept small, this in turn having the advantage that faster speeds of the fuel injection valve member are consequently achieved, since the volume flow to be pushed out of and into the control space is lower. In an advantageous development according to Patent Claim 3, two valve seats arranged in series are provided along the course of the outflow for relieving the pressure of the control space via the outflow duct. In this case, during an actuating movement of the valve member in the direction of the control space, the valve formed by the valve member and the first valve seat is opened and the valve formed by the valve member together with the second valve seat is consequently closed. When the valve member bears with its sealing surface on the first valve seat, the pressure in the control space is built up with the effect of closing the fuel injection valve. When the injection valve is to assume the opened position, the valve member lifts off from the first valve seat in response to actuation of the piezoelectric device. In this case, according to Patent Claim 4, the valve member can dwell in an intermediate position, in which the throughflow cross-section is opened at both valve seats. In this position, the injection valve member of the fuel injection valve can assume the open position, so that fuel injection, determined by the duration of this dwell position of the valve member of the control valve, takes place. In contrast, if the piezoelectric device is activated in such a way that it can execute its full actuation stroke, then, after the opening of the cross-section at the first valve seat, the valve member of the control valve comes to bear on the second valve seat, so that, in this position, the control space is once again shut off from the relief side. However, a brief relief of the control space takes place for the duration of movement from the first valve seat to the second valve seat, during which a brief injection operation becomes possible. This injection operation is utilized for preinjection. For the main injection subsequently required, the valve member can then be brought into the intermediate position between the two valve seats and, in order to terminate the main injection, can be returned onto the first valve seat again with the cooperation of the high pressure which builds up in the control space. This refinement results in an additional possibility, particularly advantageous in comparison with the designs according to Patent Claims 1 and 2, of controlling very small preinjection quantities at the lowest possible outlay. i Patent Claims 5 to 7 relate to advantageous refinements of this solution. In the development which is also advantageous, according to Patent Claim 8 the second valve seat is designed on an elastically deformable intermediate part. The advantage of this is that the necessary working capacity of the piezoelectric device as a drive for the valve member of the control valve can thereby be kept even lower. When the valve member of the control valve comes to bear on the second valve seat after the opening of the cross-section of the first valve seat, a differential pressure prevails on the elastically deformable intermediate part. On the side facing away from the control space, relief of pressure towards the relief space occurs, whilst, with the cross-section of the second valve seat closed, the high pressure prevails in the control space. As a consequence of this relationship of forces, the intermediate part can experience deformation and move in the direction of the drive side of the valve member of the control valve. This reduces the stroke which the piezoelectric device has to execute for opening the cross-section at the second valve seat, in order thereby to relieve the control space for the provision of the main injection. When the valve member lifts off from the second valve seat for this purpose, the recancellation of the one-sided exertion of force on the deformable intermediate part causes this intermediate part to return into its normal position again and consequently the relief cross-section to open rapidly. An especially advantageous refinement according to Claim 19 involves designing the tappet vicinity so as to be pressure-resistant by the advantageous high-pressure routeing of fuel to the pressure space of the fuel injection valve in the form of a longitudinal duct in the fuel injection valve. From this, the inflow duct can advantageously be introduced into the solid housing. Further advantageous refinements can be taken from the remaining Patent Claims. At the same time, particularly advantageous designs of the sealing surfaces on the valve member of the control valve are shown. Drawing 7 exemplary embodiments of the invention are illustrated in the drawing and are explained in more detail in the following description. Figure 1 shows a diagrammatic representation of a fuel injection device with its supply from a high-pressure accumulator and with a fuel injection valve of known type controlled by a control valve, Figure 2 shows a part section through a fuel injection valve according to the invention, corresponding to the detail A of Figure 1, with an illustration of the control space and of a valve member of the control valve, the said valve member being driven by a piezoelectric . device not shown any further, Figure 3 shows a second exemplary embodiment of the invention, with a control valve which has a first and a second valve seat, with a modified form of the routeing of the outflow duct, Figure 4 shows the injection valve stroke in relation to the actuating stroke of the control valve member, Figure 5 shows a third exemplary embodiment as a modification of the exemplary embodiment according to Figure 3, with a second valve seat which is designed on an elastically deformable intermediate part, in a first position of the valve member of the control valve on the first valve seat, Figure 6 shows an illustration of the control valve with the valve member located in the closed position on the second valve seat, in a modified form, having an elastically deformable intermediate part provided according to Figure 5 and an exaggerated deflection of this intermediate part in response to the differential pressure prevailing on it, Figure 7 shows an illustration of the movement profiles of the valve seat on the intermediate part and of the actuating stroke of the valve member, associated with the movement profile of the injection valve member, Figure 8 shows a fifth exemplary embodiment of the invention, with a modified design of the second valve seat and of the second sealing surface, cooperating with the latter, on the valve member. Figure 9 shows a sixth exemplary embodiment of the invention, with a multi-part valve member/ and Figure 10 shows a seventh exemplary embodiment, with an advantageous design of the valve housing and arrangement of the inflow duct in relation to the control space. Description of the exemplary embodiments A fuel injection device, by means of which a wide variation in fuel injection, in particular with injection times and injection quantities capable of being controlled with great accuracy, is possible along with high injection pressures and at a low outlay, is implemented by a so-called common-rail system. This provides a different type of fuel high-pressure source from that provided by the conventional fuel high-pressure injection pump. At the same time, however, the invention can be used both in this so-called common-rail system and in a fuel injection pump. The common-rail system is preferred in this case. The fuel high-pressure source provided in Figure 1 in the context of a common-rail pressure supply system is a fuel high-pressure reservoir 1 which is supplied with fuel from a fuel tank 4 by a fuel high-pressure feed pump 2. The pressure in the fuel high-pressure reservoir 1 is controlled by a pressure control valve 5, in conjunction with a pressure sensor 6, via an electrical control device 8. The latter also controls a fuel injection valve 9. In a known refinement, the fuel injection valve 9 has a valve housing 11 which, at one end, which is intended to be installed on the internal combustion engine, possesses injection ports 12, of which the exit out of the interior of the fuel injection valve is controlled by an injection valve member 14. The latter is designed, in the example cited, as an elongate valve needle which, at one end, possesses a sealing surface 15 cooperating with an inner valve seat. The valve needle is located inside a pressure space 16 within the valve housing, the said pressure space being connected to the fuel high-pressure reservoir 1 by means of a pressure conduit 17. Arranged in a part of enlarged diameter of this pressure space is a com¬pression spring 19 which is clamped axially between a valve plate 20 and the valve housing and which loads the injection valve member 14 in the closing direction. Provided coaxially relative to the compression spring is a tappet 21 which, on the one hand, bears on the valve plate 20 and, on the other hand, penetrates into a guide bore 22 and there, with its end face 23 which forms a moveable wall, encloses a control space 25 relative to the closed end of the guide bore. There opens into this control space an inflow duct 26, in which a throttle 27 is arranged and which, starting from the pressure space 16, always supplies fuel at a high pressure into the control space 25 via the throttle 27. An outflow duct 29 leads off from the control space 25 coaxially relative to the tappet 21 from the end face located opposite the latter and opens into a relief space 30 within the valve housing 11, this relief space leading, via a relief conduit 31 leading further, to a receptive relief space 32 which, for example, may be the fuel tank 4. In this known injection valve, the opening of the outflow duct 29 into the relief space 30 is controlled by a valve member 34 of a control valve 36 which is designed as a seat valve, this valve member being capable of being brought into the closed position or the open position by means of a piezoelectric device 35. The known fuel injection device works as follows: By means of the fuel high-pressure pump 2, preferably driven synchronously with the internal combustion engine, fuel is conveyed out of the fuel tank 4 into the high- pressure reservoir x, cne pressure oz wmcn is sec ac a preferably constant value via the pressure control valve 5 in conjunction with the pressure sensor 6. This value can also be changed, as required. The fuel available from this fuel high-pressure reservoir supplies a plurality of fuel injection valves of the type described. As long as the valve member 34 of the control valve 3 6 is in the closed position shown, this high pressure is also maintained in the control space 25 owing to the high fuel pressure supplied via the pressure conduit 17 and then applies a closing force, in addition to the compression spring 19, to the valve member 14 via the moveable wall 23, so that the injection valve member 14 is brought into the closed position and remains in this position. However, when the control valve 36 is opened, the control space 25 can be relieved via the outflow duct 29. Since the pressure falls in the control space, the closing force of the compression spring 19 is no longer sufficient to keep the injection valve member 14 in the closed position counter to the high fuel pressure applied to a pressure surface 41 of the valve member, so that the injection valve member changes to the open position. In contrast, when the valve member 34 of the control valve 3 6 closes the outflow duct 29 again, the high fuel pressure occurs immediately again in the control space 25 and then brings the injection valve 14 into the closed position again, fuel injection thereby being terminated. To improve the mode of operation of this known fuel injection device, then, the control valve has been improved according to the invention. The particular features by which the invention is implemented can be taken from the following figures. Figure 2 shows a detail of a fuel injection valve of the basic type shown in Figure 1, Figure 2 corresponding to a detail A on this fuel injection valve. There too, once again, the end face 23 is designed as a moveable wall on the tappet 21 enclosing the control space 25. The inflow duct 26 with the throttle 27 opens laterally on the circumferential wall of the guide bore 22, in such a way that the inflow is not closed by the tappet in any of its positions. On that end face 37 of the guide bore 22 which is located opposite the end face 23 of the tappet, the outflow duct 129 leads off via a recess 38 in this end face 37. The transition from this circular-cylindrical recess 38 to the outflow duct takes place via a conical valve seat 39 which has adjoining it, first, a cylindrical interspace 40 which is coaxial relative to the tappet 21 and from which the relief duct then leads off laterally, a second throttle 42 additionally being arranged in the outflow duct 129. Together with the first throttle 27, the said second throttle determines the time behaviour of the pressure relief of the control space. A valve member 44 in a form modified in relation to the valve member 34 of the control valve 36 of Figure 1 then cooperates with the valve seat 39. The said valve member has a valve tappet 45 which is guided in a bore 43 of the valve housing 11 and which is coupled, at its other end not shown here, to the piezoelectric device 35. At its end projecting into the recess 38, this valve tappet carries a head 46, to which a conical sealing surface 47 facing the valve seat 39 is attached. In the closed position of the control valve 36, as shown, this sealing surface 47 bears on the valve seat 39, so that the fuel flowing in through the inflow duct 26 builds up in the control space 25 a high pressure which keeps the injection valve member 14 in the closed position. In this position, the head 46 is subjected to the pressure which prevails in the control space 25 and which keeps the valve member in the closed position, even without actuation by the piezoelectric device. To open the control valve, the piezoelectric device is actuated in such a way that the head 46 penetrates further into the recess 38 and opens the throughflow cross-section on the valve seat. This takes place, in the initialisation, first of all counter to the high pressure in the control space. As soon as the valve member has lifted off from the valve seat 39 a little, pressure equalization occurs on the valve member, so that relatively little opening work has to be expended at the piezoelectric device for the further opening stroke. The control space is relieved and the injection valve member 14 opens. At the same time, in the illustration shown, the tappet 21 moves upwards towards the end face 37. A chamfer 24 on the end face 23 of the tappet 21 and an annular recess 28 opposite the said chamfer and located in the end face 37 form a residual space which acts as a hydraulic stop. In the region of this residual space, a residual surface of the tappet 21 always remains exposed directly to the high fuel pressure supplied via the inflow duct 26. A throttle gap remains between the end face 23 and the end face 37 in the region between this residual space and the recess 38, the said throttle gap uncoupling the relieved recess 38 from the residual space and serving also for building up pressure in the recess 38 after the closing of the valve formed at the valve seat 39 and by the valve member 44. Introducing the inflow duct 26 into the annular recess 28 forming part of the residual space affords the appre¬ciable advantage that the inflow duct 726 shown in Figure 10 can be made obliquely relative to the axis of the tappet 721, starting from a bore 59 which serves for supplying pressure to the pressure space 16 and which is guided parallel to the axis of the injection valve. If the injection valve housing is separated at the transition to the relief space 30 (Figure 1), then the inflow duct 726 can advantageously be drilled obliquely relative to the residual space 738 from the mouth 61 of the parallel bore 59, starting from this separating plane 60. The essential advantage of this is that the solid injection valve housing is maintained around the control space 725 and no wall deformations caused by the high pressure occurring in the high-pressure inflow can adversely influence the fitting play between the guide bore 722 and tappet 721. In particular, there is no need for an annular space which is formed by a separate insert and from which the inflow duct has to conduct high-pressure fuel to the control space, as shown in EP Al-0,661,442. This provides the guidance of the tappet within an insert which is surrounded by an annular space exposed to the high pressure and which therefore separates the control space from the annular space by means of only a small wall thickness. With this refinement, the injection operations can be controlled reliably and quickly at relatively low outlay in terms of the piezoelectric device 35 actuating the control valve. Since the valve member opposes high . resistance to the piezoelectric device only at the opening moment, but thereafter these resistances become virtually 0 on account of the relief of pressure in the control space 25, the piezoelectric device needs to be designed only for this specific load. In a modification of Figure 2, according to Figure 3 the outflow duct 229 can also lead off laterally from the control space 25. Furthermore, Figure 3 also shows a further advantageous refinement of the invention, in which the valve seat, provided here in a similar way to Figure 2, is now a first valve seat 139 which the interspace 40 once again adjoins, the outflow duct 229 then leading off from the said interspace to the relief space via a second throttle 142. In addition to this first valve seat 139, there is now a second valve seat 49 which is arranged coaxially relative to the first valve seat 139 and opposite the latter towards the side of the control space 25. For this purpose, the outflow duct 229 has, in an intermediate region, a valve space 50, into which the, for example, spherical head 146 of the valve member 144 can penetrate. Instead of this spherical shape, it would also be perfectly possible to have a shape, as shown in Figure 2, with a conical sealing surface 47 as a first sealing surface and with a second likewise conical sealing surface 52 which is located opposite the latter and which is designated in Figure 2 by a broken reference line as a possible alternative for use in Figure 3. In Figure 3, in the case of a spherical head the first sealing surface 147 is formed towards the side of the first valve seat 139 and, opposite the first sealing surface, a second sealing surface 152 is implemented as a continuation of the spherical shape. When the valve member 144 is actuated, this second sealing surface is brought to bear on the second valve seat 49 and, in this position, after an intermediate opening of the outflow duct 229, the valve member 144 closes the latter again. Over the duration of the stroke of the valve member 144 from its position, shown in Figure 3, on the first valve seat 139 to the second valve seat 49, relief of the control space 25 takes place in such a way that the injection valve member can open briefly. When the valve member bears with its second sealing surface 152 on the second valve seat 49 again, the pressure builds up very quickly again in the control space 25 and closes the fuel injection valve. This refinement has the very appreciable advantage that, when the valve member 144 is actuated by the piezoelectric device 35, opening and reclosing of the relief conduit, with intermediate relief of the control space, can be carried out in a single movement sequence and direction of movement, thereby making it possible to implement very short relief times. This is entirely along the lines of injection interruption between preinjection and subsequent main injection. Whereas, in all known designs, to execute this operation, a first reciprocating movement of the valve member was necessary to produce preinjection and a second reciprocating movement of the valve member was necessary to determine the main injec¬tion, now both preinjection and main injection, with injection interruption, can be controlled by means of a single reciprocating movement of the valve member. In this respect, Figure 4 shows, at the top, the stroke protiie o£ the injection valve member 14 and, assigned to this, the stroke profile of the valve member 144 of the control valve over time. The upper part of the graph indicates the brief opening of the injection valve for carrying out preinjection VE, then injection interruption SU, this being followed by the opening of the injection valve for main injection HE. The lower part of the graph indicates that, starting from the initial position with 0 stroke, the valve member 144 executes a stroke, over which preinjection takes place. At the stroke he, this preinjection is terminated and the greatest deflection of the valve member 144 is also obtained. After dwelling in this end position for the time SU, the valve member 144 subsequently runs back again into an intermediate position ZS, in which the cross-sections on the two valve seats 139 and 49 are opened for the execution of main injection HE, the final return to the first valve seat 139 taking place thereafter. In this version, the valve seats 139 and 49 are preferably located coaxially one behind the other and coaxially relative to the valve tappet of the valve member 144. A seat valve is thereby produced on each of the two valve seats. To reduce the requirements placed on the piezoelectric device for the execution of the actuating movement of the valve member, in a development of the exemplary embodiment according to Figure 3 the second valve seat is arranged as a valve seat 149 on an elastically deformable intermediate part 55. This has, for example, the form of a disc which preferably consists of metal and which is clamped sealingly between two halves of the valve housing 11. It possesses coaxially relative to the tappet 21 or to the valve member 244 a passage bore 56 which connects the valve space 150 to the control space 125. The entry of the passage bore 56 into the valve space 150 is designed as a second valve seat 349, on which the second sealing surface 352 of the valve member 344 comes sealingly to bear in its maximum deflected position. The head 346 of the valve member 344 carries a conical surface as a first sealing surface 347 and a spherical surface as a second sealing surface 352, in a modification of the exemplary embodiment according to Figure 3. However, a configuration of the head 46 of Figure 2 could also be used here. On the side towards the control space 125, the elastically deformable intermediate part has an annular recess 57 which is arranged concentrically relative to the passage bore 56 and which ensures that, starting at this annular recess 57, the elastically deformable intermediate part can be deflected more easily, especially upwards towards the valve member 344. However, this property can also be achieved by other reductions in the thickness of the intermediate part. Figure 6 shows this situation regarding the deflection of the intermediate part, but there with reference to a valve having a head 446 of the valve member 444 which is spherical according to Figure 3. When the head 446 comes with its second sealing surface to bear on the second valve seat 349, the high pressure prevailing in the fuel high-pressure reservoir can build up in the control space 25. If the valve space 150 was exposed to the same pressure as the control space 125 in the position of the valve member 344 of Figure 5, then, in the position according to Figure 6, different pressures prevail in such a way that the elastically deformable intermediate part 55 is then deformed towards the valve member 444. This process is illustrated in Figure 7. Graph parts assigned to one another and located one above the other represent, at the top, the stroke movement of the injection valve member 14, once again with the range of preinjection VE, injection interruption SU and main injection HE. In the lower part of the graph, the curve M represents the movement of the elastic intermediate part. In an initial position hmO, the intermediate part together with the second valve seat 349 is brought into a position hml in relation to the actuating travel of the valve member 444. This commences at the end of the stroke movement of the valve member 440 when, starting from the initial position V0, the valve member comes to bear on the intermediate part in the position hmO. When this position is reached, the valve member, together with the second valve seat 349 of the intermediate part, is brought into the position hml under the effect of the differential pressure now occurring and dwells there as long as the valve member 444 bears on the second valve seat 349. Subsequently, after the valve member 444 has been lifted off from the second valve seat 349 again, the latter once again assumes its initial position hmO and, as in the graph according to Figure 4, the valve member 444 assumes an intermediate position ZS, in which the control space 125 is relieved and main injection is completed. The valve member thereafter returns to its end position VO. In the range in which the diaphragm can be deflected in the stroke direction hml, the valve member can also be deflected back, so that its stroke moves back from the original end position hmO into a common end position hml. The stroke subsequently to be executed for complete opening of the valve member 444 is thus reduced in comparison with the curve version VI, represented by broken lines, which would occur if there were no elastic deflection of the intermediate part. Since the two parts, namely the valve member 444 and the elastically deformable intermediate part 55, execute a stroke in the opening direction immediately after the lift-off from the second valve seat 349, a very rapid relief for the control space 125 for the execution of main injection is obtained here. Requirements placed on the maximum stroke of the piezoelectric device are therefore lower, since the actual closing force relative to the second valve seat 349 is accompanied by the deformation of the elastically deformable intermediate part. This is eminently advantageous, since the size of a piezoelectric drive and the amount of energy provided for this purpose increase appreciably with the size of the necessary actuating stroke. With the power of the control valve remaining the same, the stroke required can be reduced in the way shown here. Various embodiments of the valve member were reproduced above. In addition, Figure 8 shows another version with a head 546 of the valve member 544 which has a conical sealing surface 547 and 552 in each case as the first and second sealing surface. The valve seats are designed correspondingly. Lastly, it is also possible, instead of a conical second sealing surface 552, to implement a flat-seat sealing surface with a correspondingly designed second valve seat. In a development according to a sixth exemplary embodiment, the valve member 644 of Figure 9 can be of two-part design, such that it has a head 646 which carries the first sealing surface 647 and, on the side facing away from this sealing surface, has a guide surface 59, on which a second valve member 60 coupled hydraulically to the valve member 644 is guided. In the exemplary embodiment, the second valve member takes the form of a ball which cooperates with a spherical, but preferably with a conical, second valve seat 649. In the position of the valve member 644 on the first valve seat 639, as shown, the ball 60 is held in bearing contact on the valve member 644 by the pressure in the control space 625. In the event of actuation, the ball comes to bear in a guided manner on the second valve seat 649. By means of such a ball, it is advantageously possible to use a standard part to achieve a sealing fit with the valve seat. WE CLAIM; 1. A fuel injection device for internal combustion engines, having a high-pressure fuel source (1) from which fuel is supplied to a fuel injection valve (9) which has an an injection valve member for controlling injection openings (12) and a control space (26), which is delimited by a movable wall (23), which is at least indirectly connected to the injection valve member (14), and which has an inlet passage (26), which is dimensioned by means of a throttle and originates from a high-pressure source, preferably from the high-pressure fuel source (1), an outlet passage (29) with a defined maximum outlet cross section to a relief space (30), at which outlet passage a valve seat (39) being arranged at the outlet passage (128) so as to face towards the control space (26), and the piezo (35) lifting the valve member (44, 46) off the valve seat (39), counter to the pressure prevailing in the control space (26), in order to open the outlet passage (129) towards the control space (26), and the valve member (44, 46) being acted on in the closing direction by the pressure in the control space (25), and the valve member (44, 46) being acted on in the closing direction by the pressure in the control space (26), characterized in that the valve seat at the outlet passage is a first valve (139), and on the control space side of this first valve seat there is a second valve seat (49), which delimits the outlet cross section of the outlet passage (229) and is closed off by an additional, second sealing surface(152), which is moved by the valve member (144, 146) under the influence of the actuation by the piezo after the valve member (144,146) has lifted off the first valve seat (139). 2. The fuel injection device as claimed in claim 1, wherein the distance between the first valve seat (139) from the second valve seat (49) is such that, in an intermediate position of the valve member (144, 146), the outlet cross sections at both valve seats are opened. 3. The fuel injection device as claimed in claim 2, wherein the valve seats (139, 49) are arranged coaxially to one another. 4. The fuel injection device as claimed in claim 3, wherein the valve member (44, 144, 344, 444, 544, 644) has a head (46, 146, 346, 446, 546, 646) which bears at least one of the sealing surfaces (47, 52, 152, 147, 347, 352, 547, 552, 647), and is arranged at the end of a rod (45) that projects through the cross section of the outlet passage which is delimited by the first valve seat (39, 139) and, between itself and the first valve seat, defines the largest outlet cross section. 5. The fuel injection device as claimed in claim 4, wherein the second sealing surface (152) and the second valve seat (49) together form a seat valve, and the valve member (144, 146), when the seat valve is closed is acted on in the opening direction by the pressure in the control space (25). 6. The fuel injection device as claimed in claim 1, wherein the second valve seat (349) together with a connecting cross section which leads onwards to the control space (25) are formed on an intermediate part (55), which is elastically defbrmable in the region and at its edges is clamped fixedly between parts of the housing (11) of the fuel injection valve. 7. The fuel injection device as claimed in claim 6, wherein the intermediate part (55) is formed as a diaphragm. 8. The fuel injection device as claimed in claim 7, wherein the diaphragm is a metal diaphragm, the deformability of which is increased by regions of reduced diaphragm thickness, in particular by annular recesses (57) which like concentrically to the second valve seat. 9. The fuel injection device as claimed in any one of the preceding claims, wherein the maximum outlet cross section is formed by a throttle (42). t 10. The fuel injection device as claimed in any one of the preceding claims, wherein the first valve seat is designed as a conical valve seat (39, 139). 11. The fuel injection device as claimed in claim 10, wherein the second valve seat is formed as a ball seat. 12. The fuel injection device as claimed in claim 10, wherein the second valve seat (552, 649) is formed as a conical seat. 13. The fuel injection device as claimed in claim 10, wherein, the second valve seat is formed as a flat seat. 14. The fuel injection device in accordance with claim 12, in which the second sealing face is embodied on a part (60) actuated by the valve member, which part comes to rest on the valve member (644, 646) in response to the pressure in the control chamber (25). 15. The fuel injection device as claimed in claim 14, wherein, the second sealing face is formed on a ball (60) which is guided on a guide surface (59) of the valve member (644, 646). 16. The fuel injection device as claimed in claims 4 to 15, wherein the rod (45) is guided in a bore (43), which runs coaxially with respect to the valve seats and between which and the first valve seat there is delimited a space (40) through which the outlet passage (129) leads to the relief space (30, 32,4). 17. A fuel injection device for internal combustion engines, substantially as herein described with reference to the accompanying drawings.

Documents:

106-mas-1997 abstract duplicate.pdf

106-mas-1997 abstract.pdf

106-mas-1997 claims duplicate.pdf

106-mas-1997 claims.pdf

106-mas-1997 correspondence others.pdf

106-mas-1997 correspondence po.pdf

106-mas-1997 description (complete) duplicate.pdf

106-mas-1997 description (complete).pdf

106-mas-1997 drawings.pdf

106-mas-1997 form-1.pdf

106-mas-1997 form-26.pdf

106-mas-1997 form-4.pdf

106-mas-1997 form-6.pdf

106-mas-1997 petition.pdf