Fuel injector with valve seat orifice plate having valve seat and drain and re-pressurization orifices

Abstract

A fuel injector includes an injector housing, an outlet check valve, an injection control valve assembly, and a valve seat orifice plate that integrates a valve seat and various orifices for outlet check valve control. In the valve seat orifice plate, a drain orifice extends between a valve seat surface and a check valve control chamber formed between a closing hydraulic surface of the outlet check valve and the valve seat orifice plate. First and second re-pressurization orifices extend between an outer surface of the valve seat orifice plate and the check valve control chamber.

Description

Technical Field

[0001] The present invention generally relates to a fuel injector for an internal combustion engine, and more specifically to a valve seat orifice plate that integrates a valve seat and discharge and repressurization orifices in a single component. Background Technology

[0002] Many modern internal combustion engines, especially compression-ignition engines, employ highly sophisticated electronically controlled fuel systems that include fuel injectors with direct-acting outlet check valves. Direct-acting outlet check valves typically include a shut-off hydraulic surface exposed to fluid pressure in the control chamber. Pressure in the control chamber is released to initiate an injection event and restored to the control chamber to terminate fuel injection. Various orifices are typically used in the orifice plate to control or assist in controlling pressure changes in the control chamber for optimal actuation of the outlet check valve. Control valves are used to selectively connect the control chamber to a lower pressure.

[0003] Over the years, engineers have experimented with various arrangements and sizes of orifices in orifice plates in numerous ways. In one known system, pressurized fuel is supplied to the control chamber through a so-called "Z-hole" in the orifice plate, and connected to low pressure through a so-called "A-hole" in a component separate from the orifice plate. In some systems, an "F-hole" is used in conjunction with the Z-hole to aid in repressurization of the control chamber. By varying the purpose, arrangement, and geometry of the various orifices, a wide range of different operating and performance characteristics can be obtained. U.S. Patent No. 8,448,878 to Ibrahim et al. relates to a fuel injector with a needle control system comprising F, A, Z, and E orifices. The disclosure by Ibrahim et al. presents a common rail fuel injector employing various orifices and teaches the different performance characteristics achievable by adjusting their respective dimensions. Summary of the Invention

[0004] In one aspect, a fuel injector includes an injector housing defining a longitudinal axis and having a fuel inlet, a fuel discharge outlet, a nozzle chamber fluidly connected to the fuel inlet, and a plurality of nozzle outlets formed therein. The fuel injector also includes an outlet check valve movable from a closed position blocking the plurality of nozzle outlets from the nozzle chamber to an open position, and having a closing hydraulic surface. The fuel injector further includes a valve seat orifice plate including a first axial side having a valve seat surface, a second axial side, and an outer surface axially between the first and second axial sides and exposed to fluid pressure from the fuel inlet. The valve seat orifice plate further includes a discharge orifice extending between the valve seat surface and a check valve control chamber formed between the closing hydraulic surface and the second axial side, and a first repressurization orifice and a second repressurization orifice each extending between the outer surface and the check valve control chamber. The fuel injector further includes an injection control valve assembly having an electric actuator, an armature, and an injection control valve movable from a closed position contacting the valve seat surface to an open position fluidly connecting the discharge orifice to the fuel discharge outlet.

[0005] On the other hand, the valve seat orifice plate for a fuel injector includes a valve seat body defining a central axis, which includes a centrally positioned discharge orifice extending between a first axial side and a second axial side of the valve seat body. The valve seat body further includes a valve seat surface formed on the first axial side and extending circumferentially around the central axis and radially outward from the centrally positioned discharge orifice; a plurality of flow grooves circumferentially distributed around the central axis and extending radially outward from the valve seat surface. The valve seat body further includes a shaped sealing surface formed on the first axial side and extending circumferentially around the central axis at radially outward locations of the plurality of flow grooves; an outer surface extending between the first and second axial sides; and a flat check valve facing surface formed on the second axial side and configured to form the wetting wall of a check valve control chamber in the fuel injector. The valve seat body further includes a repressurization orifice extending between the outer surface and the flat check valve facing surface and positioned for refilling the check valve control chamber.

[0006] In another aspect, a method of operating a fuel injector includes moving a control valve in an electrically actuated control valve assembly in the fuel injector from a closed position in contact with a valve seat orifice plate to an open position. The method further includes, based on the movement of the control valve to the open position, fluidly connecting a check valve control chamber in the fuel injector to a fuel discharge outlet of the fuel injector via a discharge orifice extending through the valve seat orifice plate. The method further includes, based on the fluid connection between the check valve control chamber and the fuel discharge outlet, moving an outlet check valve in the fuel injector from a closed position to an open position to inject fuel from a nozzle outlet, wherein in the open position, the nozzle outlet in the fuel injector is fluidly connected to a nozzle chamber. The method also includes returning the control valve to a closed position, returning the outlet check valve to a closed position, and repressurizing the control chamber using fuel flow through a first repressurization orifice and a second repressurization orifice, each extending between an outer surface of the valve seat orifice plate and the check valve control chamber. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of an internal combustion engine system according to one embodiment;

[0008] Figure 2 This is a cross-sectional side view of a fuel injector according to one embodiment;

[0009] Figure 3 This is a schematic diagram of a valve seat orifice plate and an injection control valve according to one embodiment;

[0010] Figure 4 Is it through Figure 2 A cross-sectional view of a portion of the fuel injector;

[0011] Figure 5 This is a schematic diagram of a valve seat orifice plate according to one embodiment;

[0012] Figure 6 Is it through Figure 5 A schematic cross-sectional view of a portion of the valve seat orifice plate;

[0013] Figure 7 This is a side view of a cross section through a portion of a fuel injector including a valve seat orifice plate according to another embodiment;

[0014] Figure 8 This is a schematic diagram of a valve seat orifice plate according to another embodiment;

[0015] Figure 9 Is it through Figure 8 A schematic cross-sectional view of a portion of the valve seat orifice plate;

[0016] Figure 10 This is a side view of a cross-section through a portion of a fuel injector including a valve seat orifice plate according to yet another embodiment;

[0017] Figure 11 yes Figure 10 A schematic diagram of the valve seat orifice plate;

[0018] Figure 12 Is it through Figure 11 A schematic cross-sectional view of a portion of the valve seat orifice plate;

[0019] Figure 13 This is a schematic diagram of a valve seat orifice plate according to yet another embodiment;

[0020] Figure 14 yes Figure 13 A schematic outline view of a portion of the valve seat orifice plate; and

[0021] Figure 15 This is a comparison diagram of a portion of the fuel injector according to the present invention with a known fuel injector design. Detailed Implementation

[0022] See Figure 1 The diagram illustrates an internal combustion engine system 10 according to one embodiment. The internal combustion engine system 10 includes an engine housing 12 in which a plurality of combustion cylinders 14 are formed. The engine housing 12 may include any number of cylinders in any suitable arrangement. The engine system 10 also includes a fuel system 16 having a fuel tank 18, a low-pressure pump 20, a high-pressure pump 22, and a pressurized fuel reservoir 24. A pressure sensor 26 may be coupled to the pressurized fuel reservoir 24. A pressure relief valve 28 is provided to limit excess fuel pressure and return discharged fuel to the fuel tank 18. The fuel system 16 also includes a plurality of fuel injectors 30. Each fuel injector 30 may be coupled to the pressurized fuel reservoir 24 via a fuel supply line 32 (such as a so-called bushing connector or any other suitable supply line). The pressurized fuel reservoir 24 may include a single integral fuel reservoir connected to all fuel injectors 30, or multiple separate pressurized fuel reservoirs or accumulators, each coupled to one or more fuel injectors 30. The fuel injector 30 may be similar or identical, and each includes an outlet check valve 46, an electrically actuated control valve assembly 60, and a valve seat orifice plate 70, the characteristics and functions of which will become clearer from the following description. The engine system 10 also includes an electronic control unit 33, such as an engine control unit or a dedicated fuel supply control unit, which communicates with the high-pressure pump 22, pressure sensor 26, and fuel injector 30 for purposes that will be understood by those skilled in the art of fuel systems.

[0023] See also Figure 2The diagram shows additional features of one of the fuel injectors 30 in more detail. Each fuel injector 30 (referred to as the singular below) includes an injector housing 34 defining a longitudinal axis 36 and forming therein a pressurized fuel inlet 38, a fuel discharge outlet 40, a nozzle chamber 42 fluidly connected to the fuel inlet 38, and a plurality of nozzle outlets 44. The fuel injector 30 also includes an outlet check valve 46 as described above, which is movable from a closed position blocking the nozzle outlets 44 of the nozzle chamber 42 to an open position. The outlet check valve 46 includes a closing hydraulic surface 72. Figure 2 Additional features of the fuel injector 30 are also shown, including a nozzle housing 48 having a tip 50 with a nozzle outlet 44 formed therein, a first stack 52 and a second stack 54 sandwiched between an injector body 59 attached to the nozzle housing 48 and the tip 50. An outlet check valve 46 is guided by a guide sleeve 56 positioned in the stack 54 and biased toward its closed position by a bias spring 58. A fuel filter 68 filters fuel from a associated fuel supply line 32 supplied to the fuel inlet 38. A fuel discharge outlet 40 may be fluidly connected between and within the components of the injector housing 34 to be fluidly connected to a low-pressure source inside or outside the fuel injector 30. The fuel injector 30 also includes an injection control valve assembly 60 having an electric actuator 62 such as a solenoid, an armature 64 and an injection control valve 66. In the illustrated embodiment, a lever 67 separate from the control valve 66 is attached to the armature 64. The control valve 66 is movable from a closed position in contact with the valve seat orifice plate 70 to an open position, thereby changing the fluid pressure in the check valve control chamber 74 in a manner further discussed herein.

[0024] See also Figure 3 and 4The valve seat orifice plate 70 includes a valve seat body 76 defining a central axis 78. When used in a fuel injector 30, the central axis 78 may be collinear with the longitudinal axis 36. Descriptions of features of the valve seat body 76 or valve seat orifice plate 70 herein should be understood to refer to any of these features. The valve seat body 76 includes a discharge orifice 80, typically located at the center of the valve seat body 76 and extending between a first axial side 82 and a second axial side 84 of the valve seat body 76. The valve seat body 76 also includes a valve seat surface 86 formed on the first axial side 82. The valve seat surface 86 extends circumferentially around the central axis 78 and extends radially outward from the centrally located discharge orifice 80. A plurality of flow grooves 88 are also formed in the valve seat body 76, circumferentially distributed around the central axis 78, and each flow groove extends radially outward from the valve seat surface 86. In the illustrated embodiment, the flow grooves 88 are relatively deeper radially inward and adjacent to the valve seat surface 86, and relatively shallower radially outward. The valve seat body 76 further includes a shaped sealing surface 90 formed on the first axial side 82. When used in the fuel injector 30, the shaped sealing surface 90 abuts against the injector body 59 and provides a fluid seal, or substantially a fluid seal. The shaped sealing surface 90 extends circumferentially around the central axis 78 at a radially outward location of the flow groove 88. In the illustrated embodiment, the flow groove 88 may also extend outward, thereby interrupting the circumferential profile of the shaped sealing surface 90. The shaped sealing surface 90 may be spherical in some embodiments, but in others it may be conical or have a non-spherical curved shape. The valve seat body 76 also includes an outer surface 92 axially located between the first axial side 82 and the second axial side 84, and typically extends from the first axial side 82 to the second axial side 84, facing radially outward. The outer surface 92 may be formed having two cylindrical surface segments alternating with two flat surface segments, such as... Figure 5 As shown, however, the invention is not limited thereto. The valve seat body 76 also includes a flat check valve facing surface 94, which is configured to form the wetting wall of the check valve control chamber 74 when used with the fuel injector 30 installed. The flat check valve facing surface 94 is formed on the second axial side 84 and can be positioned to contact the sleeve 56.

[0025] See also Figure 5 and 6In addition to the discharge port 80, the valve seat body 76 further includes a first repressurization port 96 and a second repressurization port 98. The first repressurization port 96 and the second repressurization port 98 each extend between the outer surface 92 and the check valve control chamber 74, and can also be understood as extending between the outer surface 92 and the flat check valve facing surface 94. The first repressurization port 96 and the second repressurization surface 98 can be positioned relative to the central axis 78 in radially outward and radially inward positions, respectively, to refill the check valve control chamber 74. It has been found that refilling the check valve control chamber 74 from both positions at or after the end of a fuel injection event can provide certain advantages in promoting a “hovering” of the outlet check valve 46 just adjacent to the valve seat orifice plate 70 rather than forming a hard stop, and in raising the outlet check valve 46 away from contacting the valve seat orifice plate 70 if a hard stop occurs.

[0026] As can also be seen from the figure, the discharge port 80 includes an unrestricted inlet end 100 opening in the flat check valve face surface 94, and a restricted outlet end 102. Unrestricted flow area generally means a larger flow area compared to a relatively small and therefore more restricted flow area. The diameter of the outlet end 102 can be several times smaller than the diameter of the inlet end 100. Figure 6 It can also be seen that the valve seat body 76 further includes a countersunk hole 104 formed in the first axial side 82. In the illustrated embodiment, the outlet end 102 opens into the countersunk hole 104, and the valve seat surface 86 is flat and extends circumferentially around the countersunk hole 104. The control valve 66 may include a ball valve with a flat side, which has a flat portion 69 in contact with the valve seat surface 86 when the control valve 66 is in the closed position. Figure 6 It can also be seen that the countersunk hole 104 can be conical. The conical shape of the countersunk hole 104 can help to tightly control the diameter of the valve seat surface 86 during manufacturing and provide an optimized flow path into the flow passage 88 above and around the valve seat surface 86. In other embodiments, a countersunk hole with at least partially straight sides or a curved profile can be provided instead of a conical countersunk hole, as discussed further herein.

[0027] The first repressurization port 96 includes an unrestricted inlet end 106 opening in the outer surface 92 and a restricted outlet end 108 opening in the flat check valve facing surface 94. The second repressurization port 98 includes an unrestricted inlet end 102 opening in the outer surface 92 and a restricted outlet end 112 opening in a centrally located discharge port 80 adjacent to the flat check valve facing surface 94. Recall that the first repressurization port 96 is fluidly connected to the check valve control chamber 74 at a position radially outward relative to the longitudinal axis 78 and the central axis 36, and the second repressurization port 98 is fluidly connected to the check valve control chamber 74 at a position radially inward relative to the longitudinal axis 78 and the central axis 36.

[0028] See Figure 7 The image shows a valve seat orifice plate 170 according to another embodiment. The valve seat orifice plate 170 includes a valve seat surface 186, which is conical, unlike the flat valve seat surface of the foregoing embodiment. Figure 7 In some embodiments, the ball valve 166 is situated within a seat formed by the seat surface 186, rather than a flat-side ball valve. In some cases, as... Figure 7 The ball-cone arrangement in the design can result in the observed desired or improved flow characteristics; however, a flat seat arrangement, such as that in the foregoing embodiments, can be more robust to resist debris damage. The seat orifice plate 170 may include discharge and repressurization orifices arranged in the same or similar manner as those in the foregoing embodiments.

[0029] See now Figure 8 and 9 The diagram illustrates a valve seat orifice plate 270 according to another embodiment, which includes a valve seat surface 286 and flow channels 288 circumferentially distributed and extending radially outward around a central axis 278 of the valve seat orifice plate 270. The valve seat orifice plate 270 may include a discharge orifice 280, a first repressurization orifice 296, and a second repressurization orifice 298. The orifices 280, 296, and 298 may have the same characteristics as those described above. Figure 4-6 Implementation examples and Figure 7 The corresponding holes in the embodiments have similar or identical arrangements and configurations. From Figure 9 As can be seen, the drain hole 280 may have a restricted outlet end 302 opening toward the countersunk hole 304. The countersunk hole 304 may include a curved surface or wall 307 adjacent to the drain hole 280 and transition to the seat surface 286 via a cylindrical surface or wall 305. In the longitudinal section shown, the profile of the countersunk hole 304 can be understood as having a bathtub shape.

[0030] Turn now Figure 10-12 The diagram illustrates a valve seat orifice plate 470 according to yet another embodiment. The valve seat orifice plate 470 may again have discharge and repressurization orifices arranged and configured similarly or identically to those in the foregoing embodiments; however, the invention is not limited thereto. The valve seat orifice plate 470 also includes a valve seat surface 486 and flow channels 488 circumferentially distributed around the central axis 478 of the valve seat orifice plate 470. The outer surface 492 of the valve seat orifice plate 470 may be generally parallel to the central axis 478 through orientation, and the flow channels 488 may have a curved bottom or bottom profile in longitudinal section, as shown in… Figure 12The flow channel in the foregoing embodiment can have a flat bottom surface. In the valve seat orifice plate 470, the geometry of the flow channel 488 can provide manufacturing advantages because the flow channel 488 can be easily formed in the valve seat orifice plate 470 using a circular grinding disc. It can also be noted that the flow channel 488 can be cut to form at least the central portion of a square-configured valve seat surface 486, such as... Figure 11 The best example shown is...

[0031] See now Figure 13 The diagram illustrates a valve seat orifice plate 670 according to yet another embodiment. The valve seat orifice plate 670 may further include discharge and repressurization orifices configured and arranged similarly or identically to those in the foregoing embodiments. The valve seat orifice plate 670 also includes a valve seat surface 686 and flow grooves 688 circumferentially distributed and extending radially outward around a central axis 678. The valve seat orifice plate 670 further includes shaped sealing surfaces 690 extending circumferentially around the central axis 678 at radially outwardly spaced locations from the flow grooves 688.

[0032] The valve seat orifice plate 670 also includes a conical transition surface 699, which may be spherical, transitioning between the valve seat surface 686 and the formed sealing surface 690. A flow groove 688 extends radially outward from a radially inward starting position 705 of the conical transition surface 699 to a radially inward ending position 703 of the formed sealing surface 690. Contrary to some other embodiments described herein, the formed sealing surface 690 may be a continuous surface uninterrupted by the flow groove. See also... Figure 14 The inner circle is shown at 705, and the location where the valve seat surface 686 intersects the conical transition surface 699 is generally marked. The outer circle 707 is defined at the location where the conical transition surface 699 intersects the shaped sealing surface 690. The shaped sealing surface 690 may be a ground spherical surface and, as described above, may be circumferentially continuous around the central axis 678. Angle 700 is defined between the central axis 678 and the conical transition surface 705, and in one embodiment may be approximately 75°.

[0033] Industrial applicability

[0034] See the accompanying drawings for general information, but especially see... Figure 2-6In this embodiment, during operation of the internal combustion engine system 10, the fuel injector 30 is operated to inject liquid fuel, such as diesel fraction fuel, into the associated combustion cylinder 30 once or multiple times during a conventional four-stroke engine cycle. Operating the fuel injector 30 to perform injection involves moving the control valve 66 in the electrically actuated control valve assembly 60 of the fuel injector 30 from a closed position in contact with the valve seat surface 86 (valve seat) of the valve seat orifice plate 70 to an open position. High-pressure fuel is supplied from the pressurized fuel reservoir 24 to the fuel injector 30 such that the high-pressure fuel resides in the nozzle chamber 42, the control chamber 74, and other locations in the fuel injector 30, including the exterior and surrounding area of ​​the valve seat orifice plate 70, before opening the outlet check valve 46. Accordingly, the outer surface 92, the shut-off hydraulic surface 72, and the check valve facing surface 94 are all exposed to the fuel pressure of the fuel inlet 38.

[0035] When control valve 66 moves away from valve seat surface 86, check valve control chamber 74 is fluidly connected to fuel discharge outlet 40 and low pressure via discharge port 80. As the pressure in control chamber 74 decreases, outlet check valve 46 moves from its closed position to an open position where nozzle outlet 44 is fluidly connected to nozzle chamber 42 to inject fuel from nozzle outlet 44. When outlet check valve 46 is raised, it will tend to retract to contact valve seat orifice plate 70, or retract to a position just separated from valve seat orifice plate 70, where outlet check valve 46 is suspended. In either case, it is generally desirable for outlet check valve 46 to have a relatively soft stop in its fully open position. Control valve 66 returns to its closed position when, for example, electric actuator 62 is de-energized and return spring pushes rod 67 down to close control valve 66. With control valve 66 now closed, pressure in control chamber 74 can rise and will act when closing hydraulic surface 72 to return outlet check valve 46 to its closed position. The repressurization control chamber 74 can occur in conjunction with fuel flow through the first repressurization port 96 and the second repressurization port 98. A first fuel flow from the first repressurization port 96 is supplied at a radially outward position, and a second fuel flow from the second repressurization port 98 is supplied at a radially inward position. As described above, the second repressurization port 98 can open to the discharge port 80, such that the second fuel flow is delivered to the control chamber 74 through the inlet end 100 of the discharge port 80.

[0036] See now Figure 15The valve seat orifice plate 70 and other components of the fuel injector 30 are shown on the right-hand side of the figure, compared with components in a known fuel injector shown on the left-hand side of the figure. Those skilled in the art will be familiar with the terminology of orifices F, A, E, and Z. According to the invention, the discharge orifice 80 and similar orifices in other embodiments can be understood as E-orifices, while the first repressurization orifice 96 can be understood as Z-orifices, and the second repressurization orifice 98 can be understood as F-orifices. In known systems, the orifice plate 770 is provided with a discharge orifice 778, which is fluidly connected to another discharge orifice 790 formed in the second component, namely the valve seat plate 771. A fill orifice 798 is also formed in the orifice plate 770. In known systems, the control valve 766 closes and opens the discharge orifice 790. It can also be noted that the discharge orifice 775 in the orifice plate 770 is flow-restricted at the inlet end, and the discharge orifice 790 in the valve seat plate 771 is flow-restricted at the outlet end. Those skilled in the art will recognize that the discharge orifice 790 is an E-orifice and the discharge orifice 775 is an A-orifice. According to the present invention, a separate valve seat plate can be eliminated, and the A-hole is not required at all. In this way, a reduction in the number of parts and a simplification of the fuel injector compared to the known designs depicted are achieved.

[0037] This specification is for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. Therefore, those skilled in the art will understand that various modifications can be made to the currently disclosed embodiments without departing from the full and reasonable scope and spirit of the invention. Other aspects, features, and advantages will become apparent from a study of the accompanying drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more”. The term “one” or similar language is used where only one item is desired. Furthermore, as used herein, the terms “has,” “have,” “having,” etc., are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “at least partially based on”, unless otherwise explicitly stated.

Claims

1. A fuel injector, comprising: An injector housing that defines a longitudinal axis and has a fuel inlet, a fuel discharge outlet, a nozzle chamber fluidly connected to the fuel inlet, and a plurality of nozzle outlets formed therein; An outlet check valve is movable from a closed position that blocks the plurality of nozzle outlets from the nozzle chamber to an open position, and has a closing hydraulic surface; A valve seat orifice plate includes a first axial side having a valve seat surface, a second axial side, and an outer surface axially located between the first axial side and the second axial side and exposed to the fluid pressure of the fuel inlet; The valve seat orifice plate further includes a discharge hole extending between the valve seat surface and the check valve control chamber formed between the shut-off hydraulic surface and the second axial side, and a first repressurization hole and a second repressurization hole extending between the outer surface and the check valve control chamber, respectively; wherein the first repressurization hole includes an inlet end opening in the outer surface and an outlet end formed on the second axial side, and the second repressurization hole includes an inlet end opening in the outer surface and an outlet end opening toward the discharge hole; as well as An injection control valve assembly, comprising an electric actuator, an armature, and an injection control valve, is movable from a closed position in contact with the valve seat surface to an open position that fluidly connects the discharge orifice to the fuel discharge outlet; in, The discharge port includes an unrestricted inlet end opening toward the second axial side and a restricted outlet end opening toward a countersunk hole formed in the first axial side; The countersunk hole is conical, and the valve seat surface is flat and extends around the circumference of the countersunk hole. The first axial side includes a plurality of flow grooves that are circumferentially distributed around the longitudinal axis and extend radially outward from the valve seat surface; the flow grooves are relatively deeper radially inward and adjacent to the valve seat surface, and relatively shallower radially outward.

2. The fuel injector according to claim 1, wherein: The discharge port is centrally located within the valve seat orifice plate and coaxial with the longitudinal axis; the injection control valve includes a flat-side ball valve having a flat portion that contacts the surface of the valve seat.

3. The fuel injector according to any one of claims 1 to 2, wherein: The first repressurization port is fluidly connected to the check valve control chamber at a position radially outward relative to the longitudinal axis, and the second repressurization port is fluidly connected to the check valve control chamber at a position radially inward relative to the longitudinal axis; as well as The inlet ends of the first repressurization orifice and the second repressurization orifice, which open in the outer surface, are unrestricted, while the outlet ends are restricted.

4. The fuel injector according to any one of claims 1 to 2, wherein the first axial side includes a shaped sealing surface extending circumferentially around the valve seat surface, and the fuel injector further includes an injector body component in contact with the shaped sealing surface, and a check valve sleeve that guides the outlet check valve and contacts the second axial side.

5. A valve seat orifice plate for a fuel injector, comprising: A valve seat body defining a central axis and including a centrally positioned discharge port extending between a first axial side and a second axial side of the valve seat body; the discharge port includes an unrestricted inlet end opening toward the second axial side and a restricted outlet end opening toward a countersunk hole formed in the first axial side; The valve seat body further includes a valve seat surface formed on the first axial side and extending circumferentially around the central axis and radially outward from the centrally located discharge hole, and a plurality of flow grooves distributed circumferentially around the central axis and extending radially outward from the valve seat surface; wherein the countersunk hole is conical, the valve seat surface is flat and extends circumferentially around the countersunk hole; the flow grooves are relatively deeper radially inward and adjacent to the valve seat surface, and relatively shallower radially outward; The valve seat body further includes a shaped sealing surface formed on the first axial side and extending circumferentially around the central axis at radially outward positions of the plurality of flow grooves; an outer surface extending between the first axial side and the second axial side; and a flat check valve facing surface formed on the second axial side and configured to form the wetting wall of the check valve control chamber in the fuel injector; and The valve seat body further includes a repressurization port extending between the outer surface and the flat check valve facing surface and positioned for refilling the check valve control chamber; the repressurization port includes a first repressurization port and a second repressurization port, wherein the first repressurization port includes an inlet end opening in the outer surface and an outlet end formed on the second axial side, and the second repressurization port includes an inlet end opening in the outer surface and an outlet end opening toward the discharge port.

6. The valve seat orifice plate according to claim 5, wherein: The first repressurization orifice is positioned radially outward relative to the central axis to refill the check valve control chamber, and the second repressurization orifice is positioned radially inward relative to the central axis to refill the check valve control chamber.

7. A method of operating a fuel injector, comprising: The control valve in the electrically actuated control valve assembly of the fuel injector is moved from a closed position in contact with a valve seat of a valve seat orifice plate to an open position; wherein the valve seat orifice plate includes a valve seat body defining a central axis and includes a discharge orifice extending between a first axial side and a second axial side of the valve seat body; wherein the discharge orifice includes an unrestricted inlet end opening toward the second axial side and a restricted outlet end opening toward a countersunk hole formed in the first axial side; the valve seat body further includes a valve seat surface; the countersunk hole is conical, and the valve seat surface is flat and extends circumferentially around the countersunk hole; wherein the first axial side includes a plurality of flow grooves circumferentially distributed around the central axis and extending radially outward from the valve seat surface; the flow grooves are relatively deeper radially inward and adjacent to the valve seat surface, and relatively shallower radially outward. Based on the movement of the control valve to the open position, the check valve control chamber in the fuel injector is fluidly connected to the fuel discharge outlet of the fuel injector through a discharge port extending through the valve seat orifice plate; Based on the fluid connection between the check valve control chamber and the fuel discharge outlet, the outlet check valve in the fuel injector is moved from the closed position to the open position to inject fuel from the nozzle outlet in the fuel injector. In the open position, the nozzle outlet in the fuel injector is fluidly connected to the nozzle chamber. Return the control valve to the closed position; Return the outlet check valve to the closed position; and The check valve control chamber is repressurized by fuel flow through a first repressurization port and a second repressurization port, each extending between the outer surface of the valve seat orifice plate and the check valve control chamber; wherein the first repressurization port includes an inlet end opening in the outer surface and an outlet end formed on the second axial side, and the second repressurization port includes an inlet end opening in the outer surface and an outlet end opening toward the discharge port.

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