Title of Invention	FUEL INJECTOR COMPRISING A PRESSURE-COMPENSATED CONTROL VALVE
Abstract	The invention relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine. According to the invention, an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve (2). Said control valve (2) opens or closes a connection from a control chamber (8) into a fuel return line (9) by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat. A bore (5, 45, 51) is embodied in the closing element (3; 19), a pin (6) being received in said bore. The diameter (36) of the bore (5; 45; 51) essentially corresponds to the diameter of the seat (4). Said pin (6) is supported on one side against a pressure pin (28), against a spring seat (27) or against the injector housing (17: 62).

Title of Invention

FUEL INJECTOR COMPRISING A PRESSURE-COMPENSATED CONTROL VALVE

Abstract

The invention relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine. According to the invention, an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve (2). Said control valve (2) opens or closes a connection from a control chamber (8) into a fuel return line (9) by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat. A bore (5, 45, 51) is embodied in the closing element (3; 19), a pin (6) being received in said bore. The diameter (36) of the bore (5; 45; 51) essentially corresponds to the diameter of the seat (4). Said pin (6) is supported on one side against a pressure pin (28), against a spring seat (27) or against the injector housing (17: 62).

Full Text	Technical field: The invention in general, relates to a fuel injector, and in particular, relates to a fuel injector having a pressure-compensated control valve in accordance with the preamble of independent claim 1. Background: An injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein a injection valve member is controlled through a magnetically driven control valve is known, for example, from EP-A 1612 403. With the help of this control valve, it is made possible to close/open an outlet throttle from a control chamber into the fuel return. On one side, the control chamber is limited by a control piston, with which an injection valve member is actuated, which opens or closes at least one injection orifice into the combustion chamber of the internal combustion chamber. The outlet throttle is received in a body, which is equipped with a tapered valve seat on the side facing away from the control chamber. A closing element connected to the armature of the solenoid valve can be adjusted in this valve seat. Formed on the closing element for this purpose is a flange positioned against the conical seat. The closing element moves on an axial rod. which is connected as single-piece to the body, in which the outlet throttle is embodied. To ensure that the valve closes fluid-tight, it is necessary to manufacture highly precise surfaces and to provide very accurate fitting of the closing element to the axial rod: to avoid swaying of the closing element that can lead to jamming, with which the seat is not completely closed. Summary: The present invention disclosed herein, describes an injector for injecting fuel into a combustion chamber of an internal combustion engine. The injector has an injection valve member, which opens or closes at least one injection orifice. It is controlled b\ a control valve. The control valve opens or closes a connection from a control chamber into a fuel return line by the positioning of a closing element in a seat or by the opening of said seat. The closing element has a bore, which receives a pin. The diameter of the bore corresponds to the diameter of the seat. The pin is supported on one side, against a pressure pin, or against a spring seat or against the injector housing. These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Brief description of drawings: The novel features of the subject matter are set forth in the appended claims hereto. The subject matter itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein the same numbers are used throughout the drawings to reference like features, and wherein: Figure 1 illustrates a section of an injector with a control valve with valve needle. Figure 2 illustrates an enlarged version of the valve seat according to figure 1. Figure 3 illustrates a section from an injector with a control valve, in which the valve seat is located on the armature. Figure 4 illustrates a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a second embodiment. Figure 5 illustrates a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a third embodiment, Detailed description: The invention relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve. The control valve opens or closes a connection from a control chamber into a fuel return line by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat. The seat is preferably a smooth flat seat and the closing element comprises a smooth surface adjustable in the scat. A bore is embodied in the closing element, a pin being received in the said bore. The diameter of the bore essentially corresponds to the diameter of the flat seat. Advantage of the inventive embodiment lies in the fact that, since the diameter of the bore essentially corresponds to the diameter of the flat seat, no axial compressive force will act on the closing element. In addition to being designed as a flat seat, the seat can assume any othei shape, such that essentially no axial forces act on the closing element. For this purpose, it is necessary that the closing element is annular, so that there does not exist any area on which compressive forces in the axial direction can act. In general, the control valve of the inventive injector is a pressure-compensated 2/2 solenoid valve. To actuate the control valve, any other actuator known to the expert is conceivable in place of the magnet. Thus, for example, a control valve, which is actuated with a piezo-actuator or any other actuator which allows a quick actuation, can be used. In a preferred embodiment, the closing element is a valve needle, on which the smooth surface adjustable in the seat is formed. The bore, in which the needle is received, is realised in the valve needle. The pin is preferably supported on one side against a pressure pin or the injector housing. Thus the fuel pressure acting on the pin is passed over to the injector housing or to the pressure pin. Thereby, the pressure pin is preferably located in such a way that it can be braced to the housing. Within the bore, no compressive force in the axial direction acts on the valve needle. Here, the pin serves only to absorb the pressure. The valve needle is guided into a smooth armature guide. For this, the armature guide encloses the valve needle on its outer periphery. Advantage of this arrangement is that the guide of the valve needle is not required to simultaneously serve as a sealing element, furthermore, since the valve needle on its outer periphery is lead into the armature, a large dimensioning of the guide diameter is possible. The guide manufacture is therefore simplified. Another advantage of the guide of the valve needle on its outer periphery is that the sealing of the outlet throttle is decoupled from the guide of the valve needle. The sealing not only happens through the flat seat but also through a scaling gap. which is present between the bore and the pin; where as the guide of the valve needle is on its outer periphery, where no sealing is required against the fuel lying below the system pressure. Particularly, small sealing gap diameter is necessary at higher fuel pressures to reduce leakage occurring. Since the guide must be smoothened for a sufficiently accurate guide of the valve needle, minimum possible diameter is provided by the working tools here. By separating the valve needle guide from the sealing against the fuel, the sealing diameter can be made considerably smaller when compared to the diameter of the smoothened guide. Hereby, the leakage flow against a guide, which simultaneously acts as a sealing surface, will be reduced. In another embodiment, the control valve is a solenoid valve, wherein the smooth surface is formed on the armature of the solenoid valve, the said smooth surface can be positioned in the flat seat to open or close the connection from the outlet throttle into the fuel return line. Advantage of this embodiment is that an additional valve needle can be omitted. Through this, less number of high-precise manufactured components will be required through which costs can be reduced. Another advantage is that only the armature mass needs to be moved enabling quick switching. In an embodiment, the armature with a projection is guided into an armature guide. which is formed on a valve piece and encloses the armature. The bore is embodied in the projection into which the pin is guided, this pin absorbs the effective compressive force in the axial direction and transfers it to the housing. Even in this embodiment form, the bore in the projection of the armature only serves to seal the outlet throttle against the fuel lying below the system pressure, through the pin received in the bore, and to absorb the compressive pressure. The guide is decoupled from the sealing function and is on the outer periphery of the projection on the armature. Another advantage of this embodiment is that since the guide is large dimensioned on its outer periphery, it is easy to manufacture it. In another embodiment, the pin that is received in the bore is a guide pin and the bore is embodied in the armature. Even in this embodiment, the smooth surface, which is positioned in the flat seat, is formed on the armature. Through the guide of the armature on the guide pin, it is possible to design the armature with a shorter guide length, thus to make a compact injector. In addition, only a precise fit is required in this case, since an additional guide is omitted. The guide pin simultaneously serves to absorb the compressive force acting in the axial direction. In this way it is ensured that the armature is pressure-compensated. In another embodiment, the armature is guided into the inner magnetic core with a guide on its outer periphery. The smooth surface, which can be adjusted in the smooth Hat seat to close or open the outlet throttle, is formed on the armature. The bore in which the pin is received is embodied in the guide, wherein the said pin absorbs the effective compressive force in the axial direction. A valve needle is not required in this embodiment also, as the armature acts as closing element. In addition, the guiding function is decoupled from the sealing function since the armature is lead into the inner magnetic core. Simultaneously, it is possible to build a compact injector, since additional guide length between the magnet and valve piece is not necessary. Figure 1 shows a section from a fuel injector with a control valve, in which a valve seat is designed as smooth surface on a valve needle. An inventive fuel injector 1 comprising a control valve 2 designed as 2/2 solenoid valve. With the control valve 2 illustrated here, the hydraulic forces are minimised through a pressure-compensation. Through this the spring force can be reduced at simultaneously low lift and large cross-sectional area. Through this, shorter switching times and better dynamic response are possible when compared to the valves known from the state-of-art. This is achieved by a bore 5 embodied in a valve needle 3. the said valve needle adjustable in a seat 4. A pin 6 is received in the bore 5. In order that no effective compressive forces in the axial direction act on the valve needle 3. the diameter of the bore 5 is essentially same as the diameter of the seat 4. An outlet throttle 7 can open or close through the seat 4; through the said outlet throttle, fuel from a control chamber 8 can be drained into a low pressure area not illustrated here through a fuel return line 9. The control chamber 8 is limited by a control piston 10 on one side. An injection valve member not represented here can be actuated through the control piston 10, wherein the said injection valve member opens or closes at least one injection orifice in a combustion chamber of an internal combustion engine. The control piston 10 is guided into a bore 1 I in a valve piece 12. Through an inlet throttle 13, fuel from annular space 14 surrounding the valve piece 12 can flow into the control chamber 8. Fhe fuel reaches into the annular space 14 from a fuel inlet 15, through a fuel channel (not represented here), fhe fuel inlet 15 is connected to a high-pressure accumulator (also not represented here), in which fuel lying under system pressure is accumulated. The valve piece 12 is screwed into an injector body 17 using a valve retaining screw 16. I'he control valve 2 is actuated by a magnet 18 realised as electro-magnet. As soon as the magnet 18 is energised, magnetic field is developed which acts on an armature 19. A bore 20, in which the valve needle 3 is guided, is embodied in the armature 19. A sleeve 21 is attached to the armature 19. The sleeve 21 serves as a guide for the valve needle 3. A collar on the sleeve 21 adjusts the valve lift, wherein the said collar is located on a disc 38 which again is located on the valve piece 12. fhe group comprising the collar on the sleeve 21, the disc 38 and the valve piece is fastened to the valve retaining screw. The valve lift is determined by the thickness of the disc 38. For limiting the lift, the extension 22 of the valve needle 3 strikes against an end face 23 of the sleeve 21. Fhe armature 19 is received in an armature chamber 24, into which fuel from the control chamber 8 flows when the control valve 2 is opened. From the armature chambe. 24, the fuel reaches into a spring seat 27 in the fuel return line 9. through a spring chamber 25 and a bore 26. On the side opposite to the control chamber 8, the pin 6 is supported against a pressure pin 28. The effective compressive force on the pin 6 is transferred to the pressure pin 28. On the side opposite to the pin 6, the pressure pin 28 is supported against a spring scat 27. With this, the compressive force is transferred further on to the spring seat 27. The spring seat 27 is again braced to a drain nozzle 29, to which the injector housing is connected. With this, the compressive force transferred from the pin 6 to the spring seat 27 via the pressure pin 28 is transferred on to the drain nozzle 29 and with it to the housing. No compressive force in axial direction acts on the valve needle 3, in the bore 5 of which the pin 6 and the pressure pin 28 are received. To position the valve needle 3 in its seat 4. a spring element 30 is received in the spring chamber 25, which positions the valve needle 3 in its seat when the magnet 18 is not energised. For this purpose, the spring element 30 is preferably a spiral spring realised as compression spring. On one side this is supported against the valve needle 3 and on the other side against the spring seat 27. Here, the spring element 30 encloses a journal 3 I formed on the spring seat 27 and the pressure pin 28. The magnet 18 is energised to start the injection. With this, a magnetic Held is developed, with which the armature 19 is pulled in the direction of the magnet 18. The armature 19 acts on a ring 32, which engages with the valve needle 3 in a groove 33. With this, the valve needle 3 together with the armature 19 moves in the direction of the magnet 18. Thereby, the valve needle 3 is guided into the sleeve 21. The movement of opening is completed, as soon as the valve needle 3 with the extension 22 strikes the end face 23 of the sleeve 21. From the control chamber 8, fuel lying under system pressure can drain off via the outlet throttle 7, via the armature chamber 24, via the spring chamber 25 and via the fuel return line 9. The pressure in the control chamber 8 reduces. With this, the control piston 10 ceases to be pressure-compensated and moves into the control chamber 8. This results in a movement of the injection valve member (not illustrated here) in the direction of the control piston 10. with which at least one injection orifice is opened and fuel flows into the combustion chamber of the internal combustion engine. Current supply to the magnet 18 is stopped to end the injection. The magnetic Held disintegrates. Therefore the armature 19 ceases to be pulled in the direction of the magnet 18. Through the spring force of the spring element 30, the valve needle 3 moves in the direction of the valve seat 4 and closes the latter. Fuel ceases to drain from the control chamber 8 via the outlet throttle 7. Fuel lying under the system pressure flows into the control chamber 8 via the inlet throttle 13 and via the annular space 14 connected with the fuel inlet 15. With this, system pressure again rises in the control chamber 8. Due to the effective compressive force on the control piston 10, it moves in the direction of the injection valve member. The injection valve member is again positioned in its seat and thereby closes at least one injection orifice. The injection is completed. Figure 2 illustrates an enlarged view of the valve seat 4. A smooth flat seat 34 is realised on the valve piece 12 to close the outlet throttle 7 tightly. Realised on the valve needle 3 is a smooth surface 35, which is positioned on the smooth flat seat 34, to close the outlet throttle 7. Since the inner diameter 36 of the smooth surface 35 corresponds to the diameter of the bore 5, no compressive force in the axiai direction acts on the valve needle 3. However, from the reasons pertaining to manufacturing, a chamfer 36 should be grinded on the valve needle 3. In this case, a minor proportion of the pressure acts on the chamfer 36 in the axial direction. To prevent fuel draining along the bore 5, via the outlet throttle 7, the pin 6 is guided into the bore 5 with tight guide play. With this, a sealing develops through a tight gap. However, the pin 6 serves only to seal the bore 5 and to ensure that no compressive force in the axial direction acts on the valve needle 3. Guide of the valve needle 3 through the pin 6 is not present. The guide of the valve needle 3 is rather in the sleeve 21. Due to the considerably large inner diameter of the sleeve 21, it is easy to manufacture this guide with the required surface quality than a corresponding guide through the bore 5. Figure 3 shows a section from a fuel injector, in which the valve seat is located on the armature of a solenoid valve. In the embodiment illustrated in the figure 3, the seat 4. with which the outlet throttle 7 can be closed or opened, is directly on a projection 40 on the armature \9. With this, no valve needle is needed to close or open the outlet throttle 7. I he projection 40 is guided into an armature guide 41, which is located on the valve piece 12. Here, the guide on the outer diameter of the projection 40 happens, so that the armature guide 41 can have correspondingly large dimension. With this, the armature guide 41 manufacturing is simplified. The armature guide 41 opens towards the outlet throttle 7 into an inner valve chamber 42.This is connected to an outer valve chamber 44 through a channel 43. A bore 45, in which the pin 6 is guided, is embodied in the projection 40. Similar to the valve needle 3 illustrated in the figure 2, a smooth surface 35 is formed on the projection 40 of the armature 19. this smooth surface will be positioned in a smooth fiat seat 34 on the valve piece 12, to close the outlet throttle 7. Thereby, the inner diameter of the bore 45 is exactly equal to the inner diameter of the smooth surface 35. Therefore no compressive force in the axial direction acts on the projection 40 and with it on the armature lc). The compressive force in the axial direction will be absorbed by the pin 6, which is supported against the pressure pin 28. The pressure pin 28 is again braced to a housing cover 46. so that the compressive force from the pin 6 will be transferred to the housing cover 46 through the pressure pin 28. The magnet 18 is energised to start the injection. With this, the armature 19 is pulled in the direction of the magnet 18. A sleeve 47 which acts as lift-stop is received into the interior of the magnet 18. The movement of the lift is ended as soon as the armature 19 strikes the sleeve 47. By the movement of the armature 19, the smooth surface 35 is lifted from the smooth flat seat 34 and so enables a connection from the outlet throttle 7 into the inner valve chamber 42. As a result, the fuel lying under the system pressure flows from the control chamber 8 into the inner valve chamber 42 via the outlet throttle 7. Phrough the channel 43, the fuel further reaches into the outer valve chamber 44 connected to a fuel return line. With this, the pressure in the control chamber 8 drops, the control piston 10 moves in the direction of the control chamber 8 and the injection valve member opens. The current supply to the magnet 18 is stopped to end the injection. The armature 19 is again moved in the direction of the control chamber 8, using a spring element 48. which is realised as a spiral compression spring in the embodiment illustrated here. With this, the smooth surface 35 formed on the projection 40 is positioned in the smooth flat seat 34. The outlet throttle 7 will be closed. Fuel lying under the system pressure flows from the annular space 14 connected to a fuel inlet via the inlet throttle 13 into the control chamber 8, till the system pressure prevails in the latter. The control piston 10 moves in the direction of the injection valve member with rise in pressure in the control chamber 8. The injection valve member is again positioned in its seat and thereby closes at least one injection orifice. The injection is completed. The spring element 48, using which the movement of the armature 19 in the direction of the control chamber 8 is supported, encloses the pressure pin 28 illustrated in this embodiment. The spring element 48 is simultaneously received in the sleeve 47. Figure 4 shows a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a second embodiment. Contrary to the embodiment illustrated in figure 3, the armature 19 in the embodiment illustrated in the figure 4 is guided on to a guide pin 50. The guide pin 50 is received in a guide gap 51. which is designed as bore in the armature 19 in the embodiment not illustrated here. The seat 4. with which the outlet throttle 7 can be closed or opened, is located on the armature 19. The valve seat 4 is preferably designed, as illustrated in figure 2, such that it has a smooth flat seal 34 on the valve piece 12 and a smooth surface 35 on the armature 19. Since the inner diameter of the smooth surface 35 on the armature 19 has the same diameter as the bore 51. which forms the guide gap with the guide pin 50, no compression force in the axial direction acts on the armature 19. It acts only on the guide pin 50. A diameter extension 52 is executed on the guide pin 50 to limit the lift 53 of the armature 19. The lift 53 of the armature 19 will be limited in that it strikes the diameter extension 52. The guide pin 50 is tightly fastened to the diameter extension 52 with a cover plate 57. which closes the solenoid valve. The connection can be for example, force-closed or form-closed. The guide pin 50 with the diameter extension 5? can also be realised as one-piece with the cover plate 57. In the embodiment illustrated here, the armature 19 and the magnet 18 are enclosed by an annular component 54. The lift 53 of the armature 19 is adjusted b> the height of the component 54 and the length of the diameter extension 52. In order that fuel can drain off into the fuel return line when the outlet throttle 7 is opened, the component 54 is preferably provided with apertures 55. The magnet 18 is energised to start the injection with the embodiment illustrated in figure 4. With this, the armature 19 is moved in the direction of the magnet 18 till it strikes the diameter extension 52. The armature 19 is lifted from the seat 4. With this, a connection is opened from the control chamber 8 to the fuel return line via the outlet throttle 7 and the apertures 55. Fuel drains off from the control chamber 8. With this, the pressure in the control chamber 8 drops and the control piston 10 moves into the control chamber 8. Thereby, the injection valve member is lifted from its seat and opens at least one injection orifice. The current supply to the magnet 18 is stopped to end the injection. Using a spring element 56, which is preferably a spiral spring designed as a compression spring, that encloses the diameter extension 52. the armature 19 with the smooth surface 35 is positioned in the smooth flat seat 34 and thereby closes the outlet throttle 7. Fuel lying under the system pressure flows into the control chamber 8 via the fuel inlet 15 and the inlet throttle 13. The pressure in the control chamber 8 rises to the system pressure. With this, the control piston 10 moves in the direction of the injection valve member. As a result, the injection valve member is again positioned in its seat and thereby closes at least one injection orifice. Figure 5 shows a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a third embodiment. The fuel injector I illustrated in the figure 5 is differentiated from the injector illustrated in the figure 4 in that the armature 19 is not guided through a guide pin 50, but in a armature guide 60 embodied in a inner magnetic core 61. The inner magnetic core 61 in the embodiment illustrated here is designed as annular projection on upper part of the housing 62, with which the injector is connected. The inner magnetic core 61 is enclosed by the magnet 18. Simultaneously, the inner magnetic core 61 serves as lift-stop 63. to limit the lift of the armature 19. A sleeve-shaped projection 64. which is guided into the armature guide 60, is formed on the armature 19. The upper part of the housing 62 is held on to the injector body 17 using a retaining nut 65. The magnet 18 is energised to start the injection. The armature 19 moves in the direction of the magnet, with which the smooth surface 35 on the armature is lifted from the smooth flat seat 34 and thereby opens the seat 4. Fuel from the control chamber 8 can drain off into the armature chamber 24 via the outlet throttle 7. With this, the pressure in the control chamber 8 drops and the control piston 10 moves into the control chamber 8. with which the injection valve member opens at least one injection orifice. Through a channel 66, fuel flows from the armature chamber 24 into the spring chamber 25 and from there into the spring seat 27 in the fuel return line 9 via a bore 26. Current supply to the magnet 18 is stopped to end the injection. The smooth surface 25 of the armature 19 is positioned in the smooth flat seat 34 and thereby closes the outlet throttle 7 in the direction of the injection valve member. The pressure i the control chamber 8 rises again and thereby moves the control piston 10 in the direction of the injection valve member. The latter is again positioned in its seat and thereby closes at least one injection orifice. To support the movement of the armature 19, a spring element 67, preferably a spiral spring designed as a compression spring, is received into the spring chamber 25. The movement of the armature 19 in the direction of the flat seat 34 is assisted by the spring force of the spring element 67, which is supported against the sleeve shaped projection 64 on the armature 19 on one side and to the spring seat 27 on the other side. The system pressure present on the outlet throttle 7 holds the pin 6. This is supported against the spring seat 27, so that the compressive force acting on the pin 6 due to the pressure is passed over to the upper part of the housing 62 via the spring seat 27. Since the bore 5 in which the pin 6 is guided is of same diameter as the inner diameter of the smooth surface 35, no compressive force in the axial direction acts on the armature 19. Thereby, the armature 19 with the sleeve-shaped projection and the smooth surface 35 can be realised as a single-piece or as two-piece as illustrated in the figure 5. For this purpose, a component, which comprises the sleeve-shaped projection 64 and the smooth surface 35, is directly connected with a plate of an armature 19 To limit the lift, an extension 69 is formed on the component, which encloses the sleeve-shaped projection 64 and the smooth surface 35, wherein the said extension strikes the lift-stop 63 when the magnet is energised with which the seat 4 is opened. Besides the embodiment illustrated in the figures 1 to 5. where the seat 4 is designed as flat-seat, the seat can be of any shape such that essentially no axial compressive forces act on the seat. This is for example always the case when the closing element is annular. Besides the embodiments illustrated here, in which the pin (6) is supported against the pressure pin (28), which is again supported against the spring seat (27), it is also possible to support the pin (6) directly against the injector housing. It is further possible that the pin (6) or the pressure pin (28) is designed as single-piece with the injector housing. For this purpose, the pin (6) or the pressure pin (28) is also graded, that is realised in many different diameters. Other advantages of the fuel injector with a pressure-compensated control valve will become better understood from the description and claims ol' an exemplars embodiment of such a unit. The inventive fuel injector with a pressure-compensated control valve of the present subject matter is not restricted to the embodiments that are mentioned above in the description. Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined. I/we claim: 1. An injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein said injector comprises an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve (2), wherein said control valve (2) opens or closes a connection from a control chamber (8) into a fuel return line (9) by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat (4); said closing element (3. 19) has a bore (5, 45, 51). which receives a pin (6); the diameter (36) of said bore (5, 45. 51) corresponds to the diameter of said seat (4). wherein said pin (6) is supported on one side, against a pressure pin (28), or against a spring seat (27) or against the injector housing (17. 62). 2. The injector as claimed in claim 1, wherein the control valve (2) is a solenoid valve or is actuated with a piezo-actuator. 3. The injector as claimed in claim 1 or 2, wherein the closing element is a valve needle (3), on which the smooth surface is formed (35). 4. The injector as claimed in claim 3, wherein the valve needle (3) is guided into a smooth armature guide (41). 5. The injector as claimed in one of the claims 1 to 4, wherein the seat (4) is a smooth flat seat (34) and the closing element (3, 19) encloses a smooth surface (35). which is adjusted in the seat (4). 6. The injector as claimed in claim 2, wherein the closing element is an armature (19) of the solenoid valve, on which the smooth surface is formed (35). 7. The injector as claimed in claim 6. wherein the armature (19) with a projection (40) is guided into a armature guide (41). which is located on a valve piece (12) and encloses the armature (19), wherein the bore (45), in which the pin (6) is guided, is provided in the projection (40). 8. The injector as claimed in claim 6, wherein the pin (6), which is received in the bore (51) is a guide pin (50) and the bore (51) is provided in the armature (19). 9. The injector as claimed in claim 6, wherein the armature (19) with a sleeve-shaped projection (64) is guided into a armature guide (60) in the inner magnetic core (61). wherein the bore (5) is provided in the sleeve-shaped projection (64). a pin (6) being received in said bore (5). 10. The injector as claimed in claim 9, wherein the pin (6) is supported against the injector housing (62) on one side.

Full Text

Technical field:
The invention in general, relates to a fuel injector, and in particular, relates to a fuel injector having a pressure-compensated control valve in accordance with the preamble of independent claim 1.
Background:
An injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein a injection valve member is controlled through a magnetically driven control valve is known, for example, from EP-A 1612 403. With the help of this control valve, it is made possible to close/open an outlet throttle from a control chamber into the fuel return. On one side, the control chamber is limited by a control piston, with which an injection valve member is actuated, which opens or closes at least one injection orifice into the combustion chamber of the internal combustion chamber. The outlet throttle is received in a body, which is equipped with a tapered valve seat on the side facing away from the control chamber. A closing element connected to the armature of the solenoid valve can be adjusted in this valve seat. Formed on the closing element for this purpose is a flange positioned against the conical seat. The closing element moves on an axial rod. which is connected as single-piece to the body, in which the outlet throttle is embodied. To ensure that the valve closes fluid-tight, it is necessary to manufacture highly precise surfaces and to provide very accurate fitting of the closing element to the axial rod: to avoid swaying of the closing element that can lead to jamming, with which the seat is not completely closed.
Summary:
The present invention disclosed herein, describes an injector for injecting fuel into a combustion chamber of an internal combustion engine. The injector has an injection valve member, which opens or closes at least one injection orifice. It is controlled b\ a control valve. The control valve opens or closes a connection from a control chamber into a fuel return line by the positioning of a closing element in a seat or by the opening of said seat. The closing element has a bore, which receives a pin. The diameter of the bore corresponds to the diameter of the seat. The pin is supported on one side, against a pressure pin, or against a spring seat or against the injector housing.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended
claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Brief description of drawings:
The novel features of the subject matter are set forth in the appended claims hereto. The subject matter itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein the same numbers are used throughout the drawings to reference like features, and wherein:
Figure 1 illustrates a section of an injector with a control valve with valve needle.
Figure 2 illustrates an enlarged version of the valve seat according to figure 1.
Figure 3 illustrates a section from an injector with a control valve, in which the valve seat is located on the armature.
Figure 4 illustrates a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a second embodiment.
Figure 5 illustrates a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a third embodiment,
Detailed description:
The invention relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve. The control valve opens or closes a connection from a control chamber into a fuel return line by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat. The seat is preferably a smooth flat seat and the closing element comprises a smooth surface adjustable in the scat. A bore is embodied in the closing element, a pin being received in the said bore. The diameter of the bore essentially corresponds to the diameter of the flat seat. Advantage of the inventive embodiment lies in the fact that, since the diameter of the bore essentially corresponds to the diameter of the flat seat, no axial compressive force will act on the closing element. In addition to being designed as a flat seat, the seat can assume any othei shape, such that essentially no axial forces act on the closing element. For this purpose, it
is necessary that the closing element is annular, so that there does not exist any area on which compressive forces in the axial direction can act.
In general, the control valve of the inventive injector is a pressure-compensated 2/2 solenoid valve. To actuate the control valve, any other actuator known to the expert is conceivable in place of the magnet. Thus, for example, a control valve, which is actuated with a piezo-actuator or any other actuator which allows a quick actuation, can be used.
In a preferred embodiment, the closing element is a valve needle, on which the smooth surface adjustable in the seat is formed. The bore, in which the needle is received, is realised in the valve needle. The pin is preferably supported on one side against a pressure pin or the injector housing. Thus the fuel pressure acting on the pin is passed over to the injector housing or to the pressure pin. Thereby, the pressure pin is preferably located in such a way that it can be braced to the housing. Within the bore, no compressive force in the axial direction acts on the valve needle. Here, the pin serves only to absorb the pressure. The valve needle is guided into a smooth armature guide. For this, the armature guide encloses the valve needle on its outer periphery. Advantage of this arrangement is that the guide of the valve needle is not required to simultaneously serve as a sealing element, furthermore, since the valve needle on its outer periphery is lead into the armature, a large dimensioning of the guide diameter is possible. The guide manufacture is therefore simplified. Another advantage of the guide of the valve needle on its outer periphery is that the sealing of the outlet throttle is decoupled from the guide of the valve needle. The sealing not only happens through the flat seat but also through a scaling gap. which is present between the bore and the pin; where as the guide of the valve needle is on its outer periphery, where no sealing is required against the fuel lying below the system pressure. Particularly, small sealing gap diameter is necessary at higher fuel pressures to reduce leakage occurring. Since the guide must be smoothened for a sufficiently accurate guide of the valve needle, minimum possible diameter is provided by the working tools here. By separating the valve needle guide from the sealing against the fuel, the sealing diameter can be made considerably smaller when compared to the diameter of the smoothened guide. Hereby, the leakage flow against a guide, which simultaneously acts as a sealing surface, will be reduced.
In another embodiment, the control valve is a solenoid valve, wherein the smooth surface is formed on the armature of the solenoid valve, the said smooth surface can be positioned in the flat seat to open or close the connection from the outlet throttle into the fuel return line. Advantage of this embodiment is that an additional valve needle can be
omitted. Through this, less number of high-precise manufactured components will be required through which costs can be reduced. Another advantage is that only the armature mass needs to be moved enabling quick switching.
In an embodiment, the armature with a projection is guided into an armature guide. which is formed on a valve piece and encloses the armature. The bore is embodied in the projection into which the pin is guided, this pin absorbs the effective compressive force in the axial direction and transfers it to the housing. Even in this embodiment form, the bore in the projection of the armature only serves to seal the outlet throttle against the fuel lying below the system pressure, through the pin received in the bore, and to absorb the compressive pressure. The guide is decoupled from the sealing function and is on the outer periphery of the projection on the armature. Another advantage of this embodiment is that since the guide is large dimensioned on its outer periphery, it is easy to manufacture it.
In another embodiment, the pin that is received in the bore is a guide pin and the bore is embodied in the armature. Even in this embodiment, the smooth surface, which is positioned in the flat seat, is formed on the armature. Through the guide of the armature on the guide pin, it is possible to design the armature with a shorter guide length, thus to make a compact injector. In addition, only a precise fit is required in this case, since an additional guide is omitted. The guide pin simultaneously serves to absorb the compressive force acting in the axial direction. In this way it is ensured that the armature is pressure-compensated.
In another embodiment, the armature is guided into the inner magnetic core with a guide on its outer periphery. The smooth surface, which can be adjusted in the smooth Hat seat to close or open the outlet throttle, is formed on the armature. The bore in which the pin is received is embodied in the guide, wherein the said pin absorbs the effective compressive force in the axial direction. A valve needle is not required in this embodiment also, as the armature acts as closing element. In addition, the guiding function is decoupled from the sealing function since the armature is lead into the inner magnetic core. Simultaneously, it is possible to build a compact injector, since additional guide length between the magnet and valve piece is not necessary.
Figure 1 shows a section from a fuel injector with a control valve, in which a valve seat is designed as smooth surface on a valve needle.
An inventive fuel injector 1 comprising a control valve 2 designed as 2/2 solenoid valve. With the control valve 2 illustrated here, the hydraulic forces are minimised through a pressure-compensation. Through this the spring force can be reduced at simultaneously
low lift and large cross-sectional area. Through this, shorter switching times and better dynamic response are possible when compared to the valves known from the state-of-art.
This is achieved by a bore 5 embodied in a valve needle 3. the said valve needle adjustable in a seat 4. A pin 6 is received in the bore 5. In order that no effective compressive forces in the axial direction act on the valve needle 3. the diameter of the bore 5 is essentially same as the diameter of the seat 4. An outlet throttle 7 can open or close through the seat 4; through the said outlet throttle, fuel from a control chamber 8 can be drained into a low pressure area not illustrated here through a fuel return line 9. The control chamber 8 is limited by a control piston 10 on one side. An injection valve member not represented here can be actuated through the control piston 10, wherein the said injection valve member opens or closes at least one injection orifice in a combustion chamber of an internal combustion engine. The control piston 10 is guided into a bore 1 I in a valve piece 12. Through an inlet throttle 13, fuel from annular space 14 surrounding the valve piece 12 can flow into the control chamber 8. Fhe fuel reaches into the annular space 14 from a fuel inlet 15, through a fuel channel (not represented here), fhe fuel inlet 15 is connected to a high-pressure accumulator (also not represented here), in which fuel lying under system pressure is accumulated.
The valve piece 12 is screwed into an injector body 17 using a valve retaining screw 16.
I'he control valve 2 is actuated by a magnet 18 realised as electro-magnet. As soon as the magnet 18 is energised, magnetic field is developed which acts on an armature 19. A bore 20, in which the valve needle 3 is guided, is embodied in the armature 19. A sleeve
21 is attached to the armature 19. The sleeve 21 serves as a guide for the valve needle 3. A collar on the sleeve 21 adjusts the valve lift, wherein the said collar is located on a disc 38 which again is located on the valve piece 12. fhe group comprising the collar on the sleeve 21, the disc 38 and the valve piece is fastened to the valve retaining screw. The valve lift is determined by the thickness of the disc 38. For limiting the lift, the extension
22 of the valve needle 3 strikes against an end face 23 of the sleeve 21.
Fhe armature 19 is received in an armature chamber 24, into which fuel from the control chamber 8 flows when the control valve 2 is opened. From the armature chambe. 24, the fuel reaches into a spring seat 27 in the fuel return line 9. through a spring chamber 25 and a bore 26.
On the side opposite to the control chamber 8, the pin 6 is supported against a pressure pin 28.
The effective compressive force on the pin 6 is transferred to the pressure pin 28. On the side opposite to the pin 6, the pressure pin 28 is supported against a spring scat 27. With this, the compressive force is transferred further on to the spring seat 27. The spring seat 27 is again braced to a drain nozzle 29, to which the injector housing is connected. With this, the compressive force transferred from the pin 6 to the spring seat 27 via the pressure pin 28 is transferred on to the drain nozzle 29 and with it to the housing. No compressive force in axial direction acts on the valve needle 3, in the bore 5 of which the pin 6 and the pressure pin 28 are received.
To position the valve needle 3 in its seat 4. a spring element 30 is received in the spring chamber 25, which positions the valve needle 3 in its seat when the magnet 18 is not energised. For this purpose, the spring element 30 is preferably a spiral spring realised as compression spring. On one side this is supported against the valve needle 3 and on the other side against the spring seat 27. Here, the spring element 30 encloses a journal 3 I formed on the spring seat 27 and the pressure pin 28.
The magnet 18 is energised to start the injection. With this, a magnetic Held is developed, with which the armature 19 is pulled in the direction of the magnet 18. The armature 19 acts on a ring 32, which engages with the valve needle 3 in a groove 33. With this, the valve needle 3 together with the armature 19 moves in the direction of the magnet 18. Thereby, the valve needle 3 is guided into the sleeve 21. The movement of opening is completed, as soon as the valve needle 3 with the extension 22 strikes the end face 23 of the sleeve 21. From the control chamber 8, fuel lying under system pressure can drain off via the outlet throttle 7, via the armature chamber 24, via the spring chamber 25 and via the fuel return line 9. The pressure in the control chamber 8 reduces. With this, the control piston 10 ceases to be pressure-compensated and moves into the control chamber 8. This results in a movement of the injection valve member (not illustrated here) in the direction of the control piston 10. with which at least one injection orifice is opened and fuel flows into the combustion chamber of the internal combustion engine.
Current supply to the magnet 18 is stopped to end the injection. The magnetic Held disintegrates. Therefore the armature 19 ceases to be pulled in the direction of the magnet 18. Through the spring force of the spring element 30, the valve needle 3 moves in the direction of the valve seat 4 and closes the latter. Fuel ceases to drain from the control chamber 8 via the outlet throttle 7. Fuel lying under the system pressure flows into the control chamber 8 via the inlet throttle 13 and via the annular space 14 connected with the fuel inlet 15. With this, system pressure again rises in the control chamber 8. Due to the
effective compressive force on the control piston 10, it moves in the direction of the injection valve member. The injection valve member is again positioned in its seat and thereby closes at least one injection orifice. The injection is completed.
Figure 2 illustrates an enlarged view of the valve seat 4.
A smooth flat seat 34 is realised on the valve piece 12 to close the outlet throttle 7 tightly. Realised on the valve needle 3 is a smooth surface 35, which is positioned on the smooth flat seat 34, to close the outlet throttle 7. Since the inner diameter 36 of the smooth surface 35 corresponds to the diameter of the bore 5, no compressive force in the axiai direction acts on the valve needle 3. However, from the reasons pertaining to manufacturing, a chamfer 36 should be grinded on the valve needle 3. In this case, a minor proportion of the pressure acts on the chamfer 36 in the axial direction. To prevent fuel draining along the bore 5, via the outlet throttle 7, the pin 6 is guided into the bore 5 with tight guide play. With this, a sealing develops through a tight gap. However, the pin 6 serves only to seal the bore 5 and to ensure that no compressive force in the axial direction acts on the valve needle 3. Guide of the valve needle 3 through the pin 6 is not present. The guide of the valve needle 3 is rather in the sleeve 21. Due to the considerably large inner diameter of the sleeve 21, it is easy to manufacture this guide with the required surface quality than a corresponding guide through the bore 5.
Figure 3 shows a section from a fuel injector, in which the valve seat is located on the armature of a solenoid valve.
In the embodiment illustrated in the figure 3, the seat 4. with which the outlet throttle 7 can be closed or opened, is directly on a projection 40 on the armature \9. With this, no valve needle is needed to close or open the outlet throttle 7. I he projection 40 is guided into an armature guide 41, which is located on the valve piece 12. Here, the guide on the outer diameter of the projection 40 happens, so that the armature guide 41 can have correspondingly large dimension. With this, the armature guide 41 manufacturing is simplified. The armature guide 41 opens towards the outlet throttle 7 into an inner valve chamber 42.This is connected to an outer valve chamber 44 through a channel 43. A bore 45, in which the pin 6 is guided, is embodied in the projection 40. Similar to the valve needle 3 illustrated in the figure 2, a smooth surface 35 is formed on the projection 40 of the armature 19. this smooth surface will be positioned in a smooth fiat seat 34 on the valve piece 12, to close the outlet throttle 7. Thereby, the inner diameter of the bore 45 is exactly equal to the inner diameter of the smooth surface 35. Therefore no compressive force in the axial direction acts on the projection 40 and with it on the armature lc). The
compressive force in the axial direction will be absorbed by the pin 6, which is supported against the pressure pin 28. The pressure pin 28 is again braced to a housing cover 46. so that the compressive force from the pin 6 will be transferred to the housing cover 46 through the pressure pin 28.
The magnet 18 is energised to start the injection. With this, the armature 19 is pulled in the direction of the magnet 18. A sleeve 47 which acts as lift-stop is received into the interior of the magnet 18. The movement of the lift is ended as soon as the armature 19 strikes the sleeve 47. By the movement of the armature 19, the smooth surface 35 is lifted from the smooth flat seat 34 and so enables a connection from the outlet throttle 7 into the inner valve chamber 42. As a result, the fuel lying under the system pressure flows from the control chamber 8 into the inner valve chamber 42 via the outlet throttle 7. Phrough the channel 43, the fuel further reaches into the outer valve chamber 44 connected to a fuel return line. With this, the pressure in the control chamber 8 drops, the control piston 10 moves in the direction of the control chamber 8 and the injection valve member opens.
The current supply to the magnet 18 is stopped to end the injection. The armature 19 is again moved in the direction of the control chamber 8, using a spring element 48. which is realised as a spiral compression spring in the embodiment illustrated here. With this, the smooth surface 35 formed on the projection 40 is positioned in the smooth flat seat 34. The outlet throttle 7 will be closed. Fuel lying under the system pressure flows from the annular space 14 connected to a fuel inlet via the inlet throttle 13 into the control chamber 8, till the system pressure prevails in the latter. The control piston 10 moves in the direction of the injection valve member with rise in pressure in the control chamber 8. The injection valve member is again positioned in its seat and thereby closes at least one injection orifice. The injection is completed.
The spring element 48, using which the movement of the armature 19 in the direction of the control chamber 8 is supported, encloses the pressure pin 28 illustrated in this embodiment. The spring element 48 is simultaneously received in the sleeve 47.
Figure 4 shows a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a second embodiment.
Contrary to the embodiment illustrated in figure 3, the armature 19 in the embodiment illustrated in the figure 4 is guided on to a guide pin 50. The guide pin 50 is received in a guide gap 51. which is designed as bore in the armature 19 in the embodiment not illustrated here. The seat 4. with which the outlet throttle 7 can be closed or opened, is located on the armature 19. The valve seat 4 is preferably designed, as
illustrated in figure 2, such that it has a smooth flat seal 34 on the valve piece 12 and a smooth surface 35 on the armature 19. Since the inner diameter of the smooth surface 35 on the armature 19 has the same diameter as the bore 51. which forms the guide gap with the guide pin 50, no compression force in the axial direction acts on the armature 19. It acts only on the guide pin 50. A diameter extension 52 is executed on the guide pin 50 to limit the lift 53 of the armature 19. The lift 53 of the armature 19 will be limited in that it strikes the diameter extension 52. The guide pin 50 is tightly fastened to the diameter extension 52 with a cover plate 57. which closes the solenoid valve. The connection can be for example, force-closed or form-closed. The guide pin 50 with the diameter extension 5? can also be realised as one-piece with the cover plate 57.
In the embodiment illustrated here, the armature 19 and the magnet 18 are enclosed by an annular component 54. The lift 53 of the armature 19 is adjusted b> the height of the component 54 and the length of the diameter extension 52.
In order that fuel can drain off into the fuel return line when the outlet throttle 7 is opened, the component 54 is preferably provided with apertures 55.
The magnet 18 is energised to start the injection with the embodiment illustrated in figure 4. With this, the armature 19 is moved in the direction of the magnet 18 till it strikes the diameter extension 52. The armature 19 is lifted from the seat 4. With this, a connection is opened from the control chamber 8 to the fuel return line via the outlet throttle 7 and the apertures 55. Fuel drains off from the control chamber 8. With this, the pressure in the control chamber 8 drops and the control piston 10 moves into the control chamber 8. Thereby, the injection valve member is lifted from its seat and opens at least one injection orifice.
The current supply to the magnet 18 is stopped to end the injection. Using a spring element 56, which is preferably a spiral spring designed as a compression spring, that encloses the diameter extension 52. the armature 19 with the smooth surface 35 is positioned in the smooth flat seat 34 and thereby closes the outlet throttle 7. Fuel lying under the system pressure flows into the control chamber 8 via the fuel inlet 15 and the inlet throttle 13. The pressure in the control chamber 8 rises to the system pressure. With this, the control piston 10 moves in the direction of the injection valve member. As a result, the injection valve member is again positioned in its seat and thereby closes at least one injection orifice.
Figure 5 shows a section from a fuel injector with a control valve, in which the valve seat is located on the armature, in a third embodiment.
The fuel injector I illustrated in the figure 5 is differentiated from the injector illustrated in the figure 4 in that the armature 19 is not guided through a guide pin 50, but in a armature guide 60 embodied in a inner magnetic core 61. The inner magnetic core 61 in the embodiment illustrated here is designed as annular projection on upper part of the housing 62, with which the injector is connected. The inner magnetic core 61 is enclosed by the magnet 18. Simultaneously, the inner magnetic core 61 serves as lift-stop 63. to limit the lift of the armature 19. A sleeve-shaped projection 64. which is guided into the armature guide 60, is formed on the armature 19.
The upper part of the housing 62 is held on to the injector body 17 using a retaining nut 65.
The magnet 18 is energised to start the injection. The armature 19 moves in the direction of the magnet, with which the smooth surface 35 on the armature is lifted from the smooth flat seat 34 and thereby opens the seat 4. Fuel from the control chamber 8 can drain off into the armature chamber 24 via the outlet throttle 7. With this, the pressure in the control chamber 8 drops and the control piston 10 moves into the control chamber 8. with which the injection valve member opens at least one injection orifice. Through a channel 66, fuel flows from the armature chamber 24 into the spring chamber 25 and from there into the spring seat 27 in the fuel return line 9 via a bore 26.
Current supply to the magnet 18 is stopped to end the injection. The smooth surface 25 of the armature 19 is positioned in the smooth flat seat 34 and thereby closes the outlet throttle 7 in the direction of the injection valve member. The pressure i the control chamber 8 rises again and thereby moves the control piston 10 in the direction of the injection valve member. The latter is again positioned in its seat and thereby closes at least one injection orifice.
To support the movement of the armature 19, a spring element 67, preferably a spiral spring designed as a compression spring, is received into the spring chamber 25. The movement of the armature 19 in the direction of the flat seat 34 is assisted by the spring force of the spring element 67, which is supported against the sleeve shaped projection 64 on the armature 19 on one side and to the spring seat 27 on the other side. The system pressure present on the outlet throttle 7 holds the pin 6. This is supported against the spring seat 27, so that the compressive force acting on the pin 6 due to the pressure is passed over to the upper part of the housing 62 via the spring seat 27. Since the bore 5 in which the pin 6 is guided is of same diameter as the inner diameter of the smooth surface 35, no compressive force in the axial direction acts on the armature 19.
Thereby, the armature 19 with the sleeve-shaped projection and the smooth surface 35 can be realised as a single-piece or as two-piece as illustrated in the figure 5. For this purpose, a component, which comprises the sleeve-shaped projection 64 and the smooth surface 35, is directly connected with a plate of an armature 19 To limit the lift, an extension 69 is formed on the component, which encloses the sleeve-shaped projection 64 and the smooth surface 35, wherein the said extension strikes the lift-stop 63 when the magnet is energised with which the seat 4 is opened.
Besides the embodiment illustrated in the figures 1 to 5. where the seat 4 is designed as flat-seat, the seat can be of any shape such that essentially no axial compressive forces act on the seat. This is for example always the case when the closing element is annular.
Besides the embodiments illustrated here, in which the pin (6) is supported against the pressure pin (28), which is again supported against the spring seat (27), it is also possible to support the pin (6) directly against the injector housing. It is further possible that the pin (6) or the pressure pin (28) is designed as single-piece with the injector housing. For this purpose, the pin (6) or the pressure pin (28) is also graded, that is realised in many different diameters.
Other advantages of the fuel injector with a pressure-compensated control valve will become better understood from the description and claims ol' an exemplars embodiment of such a unit.
The inventive fuel injector with a pressure-compensated control valve of the present subject matter is not restricted to the embodiments that are mentioned above in the description.
Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.

I/we claim:
1. An injector for injecting fuel into a combustion chamber of an internal combustion engine, wherein said injector comprises an injection valve member, which opens or closes at least one injection orifice, is controlled by a control valve (2), wherein said control valve (2) opens or closes a connection from a control chamber (8) into a fuel return line (9) by the positioning of a closing element (3, 19) in a seat (4) or by the opening of said seat (4); said closing element (3. 19) has a bore (5, 45, 51). which receives a pin (6); the diameter (36) of said bore (5, 45. 51) corresponds to the diameter of said seat (4). wherein said pin (6) is supported on one side, against a pressure pin (28), or against a spring seat (27) or against the injector housing (17. 62).
2. The injector as claimed in claim 1, wherein the control valve (2) is a solenoid valve or is actuated with a piezo-actuator.
3. The injector as claimed in claim 1 or 2, wherein the closing element is a valve needle (3), on which the smooth surface is formed (35).
4. The injector as claimed in claim 3, wherein the valve needle (3) is guided into a smooth armature guide (41).
5. The injector as claimed in one of the claims 1 to 4, wherein the seat (4) is a smooth flat seat (34) and the closing element (3, 19) encloses a smooth surface (35). which is adjusted in the seat (4).
6. The injector as claimed in claim 2, wherein the closing element is an armature (19) of the solenoid valve, on which the smooth surface is formed (35).
7. The injector as claimed in claim 6. wherein the armature (19) with a projection (40) is guided into a armature guide (41). which is located on a valve piece (12) and encloses the armature (19), wherein the bore (45), in which the pin (6) is guided, is provided in the projection (40).

8. The injector as claimed in claim 6, wherein the pin (6), which is received in the bore (51) is a guide pin (50) and the bore (51) is provided in the armature (19).
9. The injector as claimed in claim 6, wherein the armature (19) with a sleeve-shaped projection (64) is guided into a armature guide (60) in the inner magnetic core (61). wherein the bore (5) is provided in the sleeve-shaped projection (64). a pin (6) being received in said bore (5).
10. The injector as claimed in claim 9, wherein the pin (6) is supported against the injector housing (62) on one side.

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Patent Number

278118

Indian Patent Application Number

10222/DELNP/2008

PG Journal Number

52/2016

Publication Date

16-Dec-2016

Grant Date

14-Dec-2016

Date of Filing

10-Dec-2008

Name of Patentee

ROBERT BOSCH GMBH

Applicant Address

POSTFACH 30 02 20, 70442 STUTTGART (DE)

Inventors:

#	Inventor's Name	Inventor's Address
1	EISENMENGER, NADJA	BURGHERRENSTRASSE 17, 70469 STUTTGART (DE)

PCT International Classification Number

F02M 47/02

PCT International Application Number

PCT/EP2007/052551

PCT International Filing date

2007-03-19

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102006021741.1	2006-05-10	Germany