Injector for injecting fuel

Abstract

A fuel injector having a seat plate with a passage throttle; a valve insert arranged at a first side of the seat plate; a valve guide surrounding the valve insert and adapted for slidable reception of the valve insert; a spring sheath surrounding at least a section of a jet needle arranged at a second side of the valve insert, the second side opposite the first side and the seat plate; a valve chamber fluidly connected to the passage throttle; a control chamber adapted for reception of fuel; and a line arranged in the valve insert connecting the control chamber and the valve chamber to one another, wherein the line is closeable by placement of the valve insert onto the spring sheath.

Claims

1. An injector for injecting fuel comprising: a seat plate having a passage throttle; a valve insert that is arranged at one of the areal sides of the seat plate; a valve guide for the slidable reception of the valve insert; a jet needle that is arranged at the side of the valve insert disposed opposite the seat plate; a spring sheath that surrounds a section of the jet needle; a valve chamber for the reception of fuel, wherein the valve chamber is bounded by the seat plate, the valve guide, and the valve insert and extends up to the passage throttle of the seat plate; a control chamber for the reception of fuel, wherein the control chamber is bounded by the valve insert, the valve guide, the spring sheath, and the jet needle; and a line that connects the control chamber and the valve chamber to one another, wherein the line is arranged in the valve insert, and the line is closed by a placement of the valve insert onto the spring sheath.

2. An injector in accordance with claim 1, wherein the spring sheath substantially has a blind hole type cutout for the reception of the jet needle and has at least one connection line to fluidically connect the interior of the blind hole type cutout in which the jet needle is arranged to a side of the valve insert facing the spring sheath.

3. An injector in accordance with claim 1, wherein the spring sheath has a placement surface for the placement of the valve insert that, on a placement of the valve insert, closes the line in interaction with a contact surface of the valve insert surrounding an opening of the line.

4. An injector in accordance with claim 2, wherein the spring sheath has a surface that faces the valve insert, that is substantially planar, and that preferably is only interrupted by the at least one connection line into the interior of the spring sheath.

5. An injector in accordance with claim 1, wherein the placement of the valve insert on the spring sheath takes place in a plane perpendicular to the axis of rotation of the jet needle.

6. An injector in accordance with claim 1, wherein the control chamber comprises two regions or two regions that are only connected to one another by at least one connection line extending in the spring sheath.

7. An injector in accordance with claim 2, wherein the at least one connection line is a bore that preferably extends in parallel with the longitudinal direction of the jet needle.

8. An injector in accordance with claim 1, wherein a region for the placement of the valve insert on the spring sheath is a flat seal that closes the line extending in the valve insert in a placed state of the valve insert on the spring sheath.

9. An injector in accordance with claim 3, wherein the valve insert has a projecting step at the side facing the spring sheath and the opening of the line is arranged in its surface.

10. An injector in accordance with claim 9, wherein the projecting step is a step-like elevation with respect to the remaining side of the valve insert facing the spring sheath so that the contact surface is reduced on a placement on the spring sheath.

11. An injector in accordance with the invention, wherein the valve opening has at least one feed line for high pressure fuel whose connection in the control chamber is open on a placement of the valve insert on the spring sheath and is closed in a state raised therefrom.

12. An injector in accordance with claim 1, wherein the valve insert is formed in mushroom shape.

13. An injector in accordance with claim 1, wherein the line is a discharge throttle for fuel from the control chamber into the valve chamber.

14. An injector in accordance with claim 1, wherein the valve insert is rotationally symmetrical about a bore axis of the line.

15. An injector in accordance with claim 1, wherein the spring sheath is rotationally symmetrical about the axis of rotation of the jet needle.

16. A fuel injector comprising: a seat plate having a passage throttle; a valve insert arranged at a first side of the seat plate; a valve guide surrounding the valve insert and adapted for slidable reception of the valve insert; a spring sheath surrounding at least a section of a jet needle arranged at a second side of the valve insert, the second side opposite the first side and the seat plate; a valve chamber fluidly connected to the passage throttle; a control chamber adapted for reception of fuel; and a line arranged in the valve insert connecting the control chamber and the valve chamber to one another, wherein the line is closeable by placement of the valve insert onto the spring sheath.

17. The injector of claim 16, wherein the valve chamber is bounded by the seat plate, the valve guide, and the valve insert and extends to the passage throttle of the seat plate.

18. The injector of claim 16, wherein the control chamber is bounded by the valve insert, the valve guide, the spring sheath, and the jet needle.

19. The injector of claim 16, wherein the spring sheath comprises a blind hole sized to receive the at least one section of the jet needle, and wherein the spring sheath comprises at least one connection line adapted to fluidically connect the interior of the blind hole in which the jet needle is arranged to the second side of the valve insert facing the spring sheath.

20. The injector of claim 16, wherein the spring sheath has a placement surface for the placement of the valve insert that, on a placement of the valve insert, closes the line in interaction with a contact surface of the valve insert surrounding an opening of the line.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further details, features, and advantages of the described embodiments will be explained with reference to the following description of the Figures.

(2) FIG. 1 shows a sectional view of an injector for fuel injection;

(3) FIGS. 2A-D show an enlarged detail around the seat plate of the injector in different states of an injector cycle;

(4) FIGS. 3A-B show an enlarged detail around the seat plate of an injector in accordance with the invention described embodiments from different view sides;

(5) FIGS. 4A-E show an enlarged detail around the seat plate of the injector in accordance with the described embodiments in different states of the injector cycle;

(6) FIG. 5 shows a simulation result for the injection rate of the injector in accordance with the invention described embodiments in comparison with a conventional injector; and

(7) FIG. 6 shows a further simulation result for the injection rate of the injector in accordance with the invention in comparison with a conventional injector.

(8) Similar reference numerals may have been used in different figures to denote similar components. FIG. 1 is shown approximately to scale, according to some embodiments. FIGS. 1, 3A-B, and 4A-E are shown with components in proportional size with one another, according to some embodiments.

DETAILED DESCRIPTION

(9) FIG. 1 shows a sectional view of an injector for injecting fuel.

(10) The injector 1 here comprises a housing 22 that is provided with a closure cap 31 at the end remote from the nozzle 24. The electric connections 18 for controlling the injector 1 extend out of the closure cap 31. The connections 18 are connected to an electromagnet 19 that raises the armature 11 out of the sealing position of the passage throttle of the seat plate 2 against the spring force of the compression spring 21 in the energized state. The compression spring 21 here contacts a shim 20 at its end remote from the armature 11. The armature 11 is here surrounded by the armature guide 29 at which a pressure screw 30 is adjacent.

(11) The region above the seat plate 2, that extends, starting from the passage throttle of the seat plate 2, toward the armature 11 is here the low pressure region of the injector 1. The high pressure region of the injector 1 extends, starting from the throttle bore of the seat plate 2, toward the nozzle 24.

(12) The valve guide 5 and the valve insert 4 received therein are adjacent to the side of the seat plate 2 opposite the armature 11. The compression spring 27 that serves to urge the jet needle 6 into its closed position via a shim 26 placed on a protrusion of the jet needle 6 engages at the adjoining spring sheath 28, The nozzle clamping nut 25 and the sealing washer 23 complete the design of the injector 1.

(13) FIGS. 2A-D show an enlarged representation of an injector in the region around its seat plate 2. It must be noted here that these Figures do not have the characterizing feature of the present described embodiments. For better understanding, force arrows and flow arrows for the path of the fuel are drawn in the Figures.

(14) FIG. 2A shows a state in which the pilot valve (that is the armature 11 and the passage throttle 3) is closed and no injection takes place. In that starting state, the same pressure relationships are present both in the valve chamber 7 and in the control chamber 8 due to the inflow of fuel of high pressure via the feed throttle 13. The fuel flowing into the valve chamber 7 via the feed throttle 13 is here also conducted into the control chamber 8 via the first line 9.

(15) In the deenergized state of the electromagnet 19, the bore 3 of the seat plate 2 is closed by the armature 11 with the aid of the preload of the compression spring 21. The armature 11 here separates the high pressure region from the low pressure region. The armature 11 is attracted and the bore 3 in the seat plate 2 is released by the control of the electromagnet 19. The pressure beneath the seat plate 2 is thus lowered and the valve insert 4 is drawn toward the lower edge of the valve guide 5.

(16) FIG. 2B now shows a state in which the pilot valve is open, that is the armature 11 is raised from the passage bore 3. An injection of fuel by means of the injector thereby takes place.

(17) The fuel flows into the low pressure region of the injector 1 through the discharge throttle 9 (also: first line 9) in the valve guide 5 due to the pressure difference that is present. The pressure in the control chamber 8 above the jet needle 6 is thereby reduced. The needle 6 is raised from the nozzle seat and the injection begins due to the pressure drop that is thus created between the jet needle head and the jet needle body.

(18) FIG. 2C shows a state in which the pilot valve is just closing, an injection of the injector 2 is, however, still present.

(19) Therefore, as soon as the energization of the electromagnet 19 is interrupted, the return spring 21 presses the armature 11 back into the flat seat on the seat plate 2 and seals the passage throttle 3. The fuel can thereby no longer escape into the low pressure region and the pressure in the valve chamber 7 above the valve insert 4 increases (due to the continuous inflow of high pressure fuel via the feed throttle 13).

(20) FIG. 2D shows a state in which the pilot valve is closed, the needle 6 closes, and the injection is thereby ended. The sectional plane shown is rotated with respect to the sectional planes of FIGS. 2A-C to be able to explain elements previously not shown.

(21) Once an equilibrium of forces is achieved via the valve insert 4, the latter is pressed downward and releases the two large diagonals of filling bores 12 (also: feed lines 12) in the valve guide 5. These bores 12 form a direct connection between the high pressure volume in the injector 1 and the control chamber 8 above the injector needle 6. The pressure in the control chamber 8 thereby increases very quickly above the needle 6, which results in a fast closing of the nozzle by the needle 6. The filling bores 12 are for the function of the injector 1 here, but offer the advantage of a very fast closing of the needle 6.

(22) FIGS. 3A-B now show a partial region of the injector 1 in accordance with the described embodiments.

(23) The closure element 11 here cooperates in a known manner with the passage throttle 3 of the seat plate 2. The valve chamber 7 is connected to the high pressure region via a feed throttle 13. The valve guide 5 adjoining the valve chamber 7 slidably receives the valve insert 4.

(24) There is also a first line 9 that can connect the valve chamber 7 to the control chamber 8. The line 9 is in this respect arranged in the valve insert 4. If the valve insert 4 is movably seated in the longitudinal direction on the flat seat 28, the line 9 is blocked. A fluidic connection of the valve chamber 7 and the control chamber 8 is then not present. The jet needle arranged in the interior of the spring sheath 14 is raised with the aid of the pressure in the control chamber 8. At least one connection line 32 through the spring sheath 14 here provides that a pressure change also moves into the interior of the spring sheath 14.

(25) FIG. 3B here shows a sectional view whose sectional plane has been rotated by 90° in comparison with the view of FIG. 3A. The feed lines 12 can now be recognized that do not have any flow communication with the control chamber 8 on an abutment of the valve guide 4 at the lower margin of the valve guide 4. If, in contrast, the valve insert 4 moves in the direction of the needle 6, a gap is produced between the lower margin of the valve guide 5 and the feed liens 13 introduce high pressure fuel into the control chamber 8. Reference numeral 17 designates the high pressure region of the fuel here.

(26) FIGS. 4A-E all show a control valve region of the injector The control valve region is assembled from the components armature 11, seat plate 2, control valve 4, 5, the spring sheath 14, and the jet needle 6.

(27) This assembly controls the opening and closing of the jet needle 6 and is thus decisive for the ensuring of the injector function and the performance of the injector 1. It is possible by this valve to determine the speed of the opening and closing of the jet needle 6 and its control times and thus to determine the injection duration and amount. It is possible due to the precise control to introduce targeted multiple injections during a cycle and to thereby provide a more complete combustion that in turn results in a reduction of pollutants.

(28) The seat plate 2 in combination with the armature 11 separates the high pressure region from the magnet/leak region. The control valve 4, 5 separates the control chamber 8 from the valve chamber 7 (also: upper control chamber). It is a three-way valve, also called a mushroom valve, and is composed of the valve guide 5 and the valve insert 4.

(29) The valve chamber 7 is delineated by the components armature 11, seat plate 2, and control valve 4, 5.

(30) The control chamber 8 is delineated by the components control valve 4, 5, spring sheath 14, and jet needle 6. It is produced from two regions that are in communication by at least one, preferably three, axial connection bores 32 in the spring sheath 14. The control chamber volume results from the two regions and from the at least one axial connection bore 32.

(31) The basic function will be explained in the following here with reference to FIGS. 4A-E.

(32) It can be seen from FIG. 4A that the armature 11 closes the throttle bore 3 of the seat plate 2 in the deenergized state of the magnet 19 and prevents an outflow of the fuel from the valve chamber 7 into the leak region 15. The valve insert 4 is located at the lower abutment and lies on the flat seal 28 on the spring sheath 14. The seat plate 2 is furthermore pressed toward the injector housing 22 and provides a radial seal between the high pressure region and the leak region and between the high pressure region 17 and the valve chamber 7 due to the high surface quality and the planarity at the contact surface. There is thus no permanent leak (Position 1).

(33) FIG. 4B shows that as soon as the magnet 19 is energized and the armature 11 is thereby raised, fuel can flow through the throttle bore 3 of the seat plate 2 out of the valve chamber 7 into the leak region 15 and thus produces a pressure drop in the valve chamber 7. A pressure difference arises between the valve chamber 7 and the control chamber 8 due to the pressure drop. As long as the valve insert 4 is at the lower abutment and the flat seat 28 on the spring sheath 14 seals, no fuel can flow onward into the valve chamber 7 via the drainage throttle 9. (Position 2).

(34) How the generated pressure difference provides that the valve insert 4 is pressed upward can be seen in FIG. 4C. If the valve insert 4 is at the upper abutment, the connection to the high pressure region 17 via the radial feed bores 12 in the valve guide 5 is sealed. Since the seal at the flat seat 28 and thus the discharge throttle 9 (also: line) is released once the valve insert 4 has moved upward, the fuel flows through the discharge throttle 9 in the valve insert 4 out of the control chamber 8 into the valve chamber 7, whereby in turn a pressure equilibrium is produced between the valve chamber 7 and the control chamber 8 (Position 3). The pressure drop in the control chamber 8 that results from this in comparison with the high pressure region 17 results in a raising of the jet needle 6, whereby the blind hole of the nozzle 24 is released and an injection of the injector 1 into the combustion chamber takes place.

(35) FIG. 4D shows the state as soon as the magnet 19 is no longer energized and the armature closes the throttle bore 3 of the seat plate 2.

(36) The pressure difference between the valve chamber 7 and the control chamber 8 is adopted due to the fuel flowing out of the high pressure region 17 via the feed throttle 13 of the valve guide 5 (Position 4).

(37) The valve insert 4 is pressed downward by the pressure buildup in the valve chamber 7 and in so doing the feed bores 12 of the valve guide 5 are released and the control chamber 8 is abruptly filled with fuel from the high pressure region 17 (Position 5, cf. FIG. 4E).

(38) As a further consequence, the same pressure level is adopted in the valve chamber 7 and in the control chamber 8 as in the high pressure region 17. The jet needle 6 is again pressed into the seat of the nozzle body by the pressure applied in the control chamber 8 and assisted by the force of the jet needle spring 21 and thus ends the injection into the combustion chamber.

(39) FIG. 5 shows the results of a simulation in comparison with a conventional injector.

(40) It can be recognized that the valve insert of the embodiment in accordance with the invention moves faster than that of conventional injectors. The graph II is here an implementation of the invention in accordance with the invention, whereas the graph I maps a conventional injector.

(41) FIG. 6 shows that with an identical control, the injector in accordance with the described embodiments responds faster, that is has a higher injection rate in mg/ms, than a conventional injector. The graph II here shows the implementation in accordance with the described embodiments; graph I a conventional injector.

(42) FIGS. 1, 2A-B, 3A-B, and 4A-E show example configurations with relative positioning of the various components. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elements shown above/below one another, at opposite sides to one another, or to the left/right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a “top” of the component and a bottommost element or point of the element may be referred to as a “bottom” of the component, in at least one example. As used herein, top/bottom, upper/lower, above/below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example.

(43) The foregoing description is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and processes shown and described herein. Accordingly, all suitable modifications and equivalents may be considered as falling within the scope of the invention as defined by the claims which follow.

REFERENCE NUMERAL LIST

(44) 1 injector 2 seat plate 3 passage throttle 4 valve insert 5 valve guide 6 jet needle 7 valve chamber 8 control chamber 9 first line 10 second line 11 closure element 12 feed line 13 feed throttle 14 spring sheath 15 leak region 16 connection bore 17 high pressure region 18 electrical connection 19 electromagnet 20 shim 21 compression spring 22 housing 23 sealing washer 24 nozzle 25 nozzle clamping nut 26 shim 27 compression spring 28 flat seat 29 armature guide 30 pressure screw 31 closure cap 32 connection line 33 step