Fuel injector with internal leakage passage to injector drain

Abstract

A fuel injector body includes a body comprising an at least partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction. A first counterbore and a first cavity extend from a first end toward a second end, and an outer interface portion includes a sealing surface axially disposed between the first end and a shoulder. The first cavity defines a floor surface and an outer peripheral surface, and the body further includes a leakage passage extending from the floor surface, the leakage passage being in communication with the first cavity.

Description

Technical Field

[0001] This invention generally relates to fuel injectors using a fuel injector body with a solenoid assembly, which can be damaged due to leakage at the interface between the nozzle and the fuel injector body. More specifically, this invention relates to fuel injectors having features for reducing the risk of leakage and potential damage to the solenoid assembly or other components of the fuel injector. Background Technology

[0002] Fuel injectors are used in internal combustion engines to inject fuel into the combustion chamber before the air / fuel mixture is ignited. These fuel injectors are typically manufactured as assemblies of multiple components to aid in their production and repair. For example, fuel injector assemblies are usually assembled using nozzles that interface with the fuel injector body. A connector may be located between the nozzle and the fuel injector body, through which high-pressure fuel can leak.

[0003] To avoid the need for face seals at the interface, which introduces component stacking uncertainties, this uncertainty can lead to leaks. Furthermore, machining such face seal features can be expensive. Any remedies for these problems can be constrained as "direct replacement" solutions. That is, fuel injector assemblies with such solutions may need to operate in existing engines by fitting into existing housings.

[0004] Furthermore, these fuel injector assemblies can employ solenoid assemblies that actuate fuel injection. In some current designs, when problems occur in the nozzle (such as components becoming stuck), an effective path for high-pressure fuel flow to the drain pipe is not provided. This can lead to fuel contamination entering the engine oil. Additionally, damage to the solenoid assembly or other components of the fuel injector may also occur.

[0005] Similarly, remedies for these problems can be constrained to make the solution a "direct replacement" solution. Summary of the Invention

[0006] A fuel injector body is provided for use with a fuel injector according to an embodiment of the invention. The fuel injector body may include a body comprising at least a partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction; a first end axially disposed along the longitudinal axis; a second end axially disposed along the longitudinal axis; a first countersunk hole and a first cavity extending from the first end toward the second end; and an external interface portion including a sealing surface axially disposed between the first end and a shoulder. The first cavity may define a bottom surface and an outer peripheral surface, and the body may further include a leakage passage extending from the bottom surface, the leakage passage communicating with the first cavity.

[0007] A fuel injector body is provided for use with a fuel injector according to another embodiment of the invention. The fuel injector body may include a body comprising at least a partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction. A first end may be axially disposed along the longitudinal axis, and a second end may be axially disposed along the longitudinal axis. A first countersunk hole and a first cavity may extend from the first end toward the second end, and an externally projecting attachment portion may include a sealing surface axially disposed between the first end and a shoulder. The first cavity may define a bottom surface and an outer peripheral surface, and the body further includes a leakage channel extending from the bottom surface, and the outer peripheral surface may define a cavity diameter, and the sealing surface may define a sealing surface diameter. The ratio of the sealing surface diameter to the cavity diameter may be in the range of 0.3 to 4.4.

[0008] A fuel injector assembly according to an embodiment of the present invention is provided. The assembly may include a fuel injector component defining a pressurized fuel chamber, a check valve assembly in fluid communication with the pressurized fuel chamber, and a fuel injector body comprising at least a partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction, a first end disposed along the longitudinal axis, a second end disposed along the longitudinal axis, and further defining a first countersunk hole and a first cavity, the first cavity extending longitudinally from the first end toward the second end and terminating nearby thereon. A nozzle may define a first longitudinal end, a second longitudinal end disposed longitudinally adjacent to the first end of the fuel injector body, a second countersunk hole, and a second cavity extending longitudinally from the second longitudinal end toward the first longitudinal end. The first end of the fuel injector body may be disposed in the second countersunk hole and the second cavity of the nozzle, thereby forming an interface region with the nozzle and the seam between the fuel injector body and the nozzle. The fuel injector body may further define a supply passage communicating with the pressurized fuel chamber and a leakage passage extending from the first cavity. Attached Figure Description

[0009] Figure 1 This is a perspective view of an engine employing various embodiments of the fuel injector of the present invention.

[0010] Figure 2 It is shown in Figure 1 A side sectional view of a single cylinder of an engine using a fuel injector.

[0011] Figure 3 This is a side sectional view of a fuel injector assembly that can use a fuel injector body with a thin-walled countersunk hole that contacts a radial seal housed in a nozzle.

[0012] Figure 4 yes Figure 3 A magnified detail of the fuel injector assembly, which more clearly shows the radial seal and thin-walled countersunk hole.

[0013] Figure 5 This is a side sectional view of a fuel injector assembly that can use a fuel injector body with an internal leakage channel connecting a low-pressure discharge groove on the outer periphery of the fuel injector body to a countersunk cavity surrounded by a nozzle. Figure 3 and Figure 5 The embodiments may be substantially the same or even identical, but are not required to be so.

[0014] Figure 6 yes Figure 5 The enlarged detail of the fuel injector assembly more clearly shows the connection between the low-pressure discharge groove on the outer periphery of the fuel injector body and the internal leakage channel of the counterbore cavity surrounded by the nozzle. Detailed Implementation

[0015] Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the drawings, the same reference numerals are used wherever possible to denote the same or similar parts. In some cases, reference numerals will be indicated in this specification, and the drawings will show reference numerals followed by letters such as 100a, 100b, or apostrophes such as 100', 100", etc. It should be understood that the use of letters or apostrophes immediately following reference numerals indicates that these features have similar shapes and functions similarly to the usual case when the geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters or apostrophes are generally not included herein, but may be shown in the drawings to indicate repetition of features discussed in this written specification.

[0016] While the applications discussed herein primarily concern common rail unit injectors, where fuel is supplied from a common source under high pressure and is not pressurized within the fuel injector, it should be understood that in other embodiments, fuel injectors using the same features described herein can be powered for injection in a different manner, such as mechanically, hydraulically, or otherwise controlled. Similarly, the type of fuel injected by the injector can vary and includes diesel fuel, gasoline, etc. Therefore, the applications of the embodiments discussed herein are applicable to a wide variety of engine types and a variety of machines driven by such engines.

[0017] For example, Figure 1 The diagram illustrates an internal combustion engine 100 that may employ various embodiments of a fuel injector assembly. The engine 100 may include an engine body 102 in which a piston (not shown) reciprocates, and a cylinder head 104 that may include various engine components for introducing fluid into orifices / combustion chambers located in the engine body 102.

[0018] Turning Figure 2The diagram shows a cross-section of a portion of an engine 100, revealing a combustion chamber 106, which may have a generally cylindrical shape defined within a cylinder bore 108 formed within the crankcase or engine block 102 of the engine 100. The combustion chamber 106 is further defined at one end by a fire-layer surface 110 of a cylinder head 104 and at the other end by a crown 111 of a piston 111a reciprocating within the bore 108 and connected to a connecting rod 124, which in turn connects to a crankshaft (not shown). A fuel injector 112 is mounted in the cylinder head 104. The injector 112 has a tip 114 that protrudes through the fire-layer surface 110 within the combustion chamber 106, allowing it to inject fuel directly into the combustion chamber 106.

[0019] During operation of engine 100, air enters combustion chamber 106 via intake passage 115 when one or more intake valves 117 (one shown) open during the intake stroke. In known configurations, high-pressure fuel is allowed to flow through nozzle openings in tip 114 to form a fuel jet entering combustion chamber 106. Each nozzle opening produces a fuel jet 118 that is generally dispersed to produce a predetermined fuel / air mixture, such as... Figure 1 and 2 The compression ignition engine shown is automatically ignited and combusted. The fuel jet 118 can be provided from the injector at an angle β between 110 and 150 degrees, but other angles may also be used. In some embodiments, a single nozzle opening may be provided, etc. After combustion, exhaust gas is discharged from the combustion chamber through exhaust duct 120 when one or more exhaust valves 122 (one shown) open during the exhaust stroke.

[0020] The uniformity and extent of fuel / air mixing in the combustion chamber are related to combustion efficiency and the amount and type of combustion byproducts formed. For example, a fuel-rich mixture that is partially present in the combustion chamber 106 due to inadequate mixing during combustion may result in higher soot emissions and lower combustion efficiency.

[0021] Turn now Figures 3 to 6 The configuration and operation of the fuel injector assembly 200, which can be used in the engine 100 just described, according to an embodiment of the invention, will now be discussed in general.

[0022] Figure 3 In the fuel injector assembly 200, there are fuel injector body 300 defining a common rail inlet 302 and nozzle 400 including injection outlet 402.

[0023] Focus on Figure 3The fuel injector body 300, as seen in the figure, includes an exhaust outlet 304 and a low-pressure exhaust recess 322b in fluid communication with the exhaust outlet 304. The common rail inlet 302 may take the form of a tapered seat to sealably engage a sleeve fluidly connected to the common rail pressure source, but this is not mandatory. A solenoid actuator 202 (which may be an assembly) may be disposed within the injector body 300 and includes an armature 204 movable relative to the stator assembly 206. The stator assembly 206 includes pole pieces 208 flush with the air gap plane 212 and a stop pin 210 (only when...). Figure 6 (as shown in the image).

[0024] Figure 6 In this configuration, the stator assembly 206 may have virtually no empty space between the electrode 208 and the centerline (which may be the same as the longitudinal axis 306 of the fuel injector body 300, but is not required to be). Furthermore, the stop pin 210 may be surrounded by the electrode 208, but radially spaced from it, such as by a plastic filler material, which may also be used to magnetically isolate the stop pin 210 from the electrode 208.

[0025] Let's refer to each other. Figure 3 and Figure 4 The solenoid actuator 202 is operatively coupled to a check valve assembly 214, which includes a closing hydraulic surface 213 exposed to fluid pressure in a pressurized fuel chamber 215 disposed in the nozzle 400. The check valve assembly 214 is movable between a closed position (as shown) that blocks the injection outlet 402 and an open position that fluidly connects the common rail inlet 302 to the injection outlet 402. The check valve assembly 214 also includes an open hydraulic surface 216 exposed to fluid pressure in the common rail inlet 302 corresponding to the pressure in the common rail (not shown).

[0026] like Figure 4 As best shown, a control valve member 218 (e.g., a ball) may be provided, which is not attached to but is constrained between the pusher 220 and the seat 222 of the valve plate 224. The control valve member 218 is movable between a closed position (as shown) in contact with the seat 222 and an open position not in contact with the seat 222 to fluidly connect the pressurized fuel chamber 215 to the discharge outlet 304. The pusher 220 interacts with the armature 204 at one end and with the control valve member 218 at the opposite end so that the control valve member 218 moves between its closed and open positions in response to the de-energization and energization of the solenoid actuator 202, respectively.

[0027] While other configurations would fall within the scope of this invention, the pressurized fuel chamber 215 is shown as being partially defined by the sleeve 226 and the orifice 228. The bias spring 230 (see also...) Figure 3The sleeve 226 can be operably positioned to simultaneously bias the sleeve 226 into contact with the orifice 228 and to bias the check valve member 214 toward its downward closed position, as shown. Other springs 230a, 230b may be provided (see Figure 230). Figure 6 The armature 204 is biased to contact the pusher 220 with the seat 222 and to contact the pusher 220 with the armature 204.

[0028] When the fuel injector assembly 200 is in injection configuration, the common rail inlet 302 is fluidly connected (fluidly communicated) to the exhaust outlet 304 through the orifice 232 of the orifice member 228 (see Figure 4 These orifices can help to end the injection event more abruptly by connecting the pressurized fuel chamber 215 to the high pressure in the common rail inlet 302 at the end of the injection event. That is, the dimensions of these orifices 232 can be determined to affect the rate at which the needle / check valve member 214 rises from its closed position to its open position by influencing the rate at which fuel escapes through the control valve member 218 to the discharge outlet 304. These features may be omitted in other embodiments of the invention.

[0029] The operation of the fuel injector assembly 200 during the injection event will be discussed in more detail below.

[0030] See also Figure 3 and Figure 4 Embodiments of a fuel injector assembly 200 that may have features for limiting or treating leaks will now be discussed.

[0031] from Figure 3 Initially, the fuel injector assembly 200 may include fuel injector components (e.g., nozzle 400, sleeve 226) defining a pressurized fuel chamber 215 and a check valve assembly 214a in fluid communication with the pressurized fuel chamber 215. The check valve assembly 214a may be disposed in the nozzle 400 or the sleeve 226, etc.

[0032] For example Figure 4 As best shown, the fuel injector body 300 can be configured to include at least a partially annular shape defining a longitudinal axis 306 (which may be a centerline), a circumferential direction 308, and a radial direction 310. The first end 312 and the second end 312a can be disposed along the longitudinal axis (see [reference]). Figure 3 The fuel injector body 300 may further define the first countersunk hole 314 and the first cavity 314a (see...). Figure 4 The first cavity 314a extends longitudinally from the first end 312 toward the second end 312a and terminates near it.

[0033] Additionally, a nozzle 400 may be provided, which defines a first longitudinal end 404 (see...).Figure 3 ) and the second longitudinal end 404a (see Figure 4 The second longitudinal end 404a is longitudinally adjacent to the first end 312 of the fuel injector body 300. The nozzle may define a second countersunk hole 406 having a second cavity 406a that extends longitudinally from the second longitudinal end 404a toward the first longitudinal end 404.

[0034] During assembly, such as Figure 4 As best shown, a first end 312 of the fuel injector body 300 may be disposed in the second countersunk hole 406 and the second cavity 406a of the nozzle 400, forming an interface region 244 with the nozzle 400 and a seam 246 between the fuel injector body 300 and the nozzle 400. In this region, the fuel injector assembly 200 may further define a radial sealing receiving groove 248 disposed longitudinally along the seam 246. The groove 248 may be formed on the fuel injector body 300 or the nozzle 400. A seal 250 is typically disposed in the radial sealing receiving groove 248 before assembly into the engine.

[0035] for Figure 4 In the embodiment shown, the second cavity 406a of the nozzle 400 includes a radially inner circumferential surface 408 defining a radially sealing receiving groove 248.

[0036] To provide a robust design, the fuel injector assembly 200 may define a minimum sealing receiver groove inner diameter 410, a minimum first cavity diameter 316 defined by a first cavity circumferential surface 315, and the ratio of the minimum sealing receiver groove inner diameter 410 to the minimum first cavity diameter may be in the range of 1.1 to 4.0.

[0037] More specifically, the fuel injector body 300 may define a radial wall thickness 318, which is radially disposed between the radial sealing receiving groove 248 and the circumferential surface 315 of the first cavity in the range of 5.0 mm to 22.0 mm.

[0038] Similarly, the nozzle 400 may define a radial outer circumferential surface 412, and a minimum radial wall thickness 414, measured radially from the radial outer circumferential surface 412 to the radial sealing receiving groove 248, in the range of 7.0 mm to 22.0 mm.

[0039] Observe more closely Figure 4 The interface region 244 shows that it includes engaging threads 252. It is conceivable that other forms of nozzle engagement or attachment to the fuel injector body, as well as other ratios and size ranges, are possible in other embodiments of the invention.

[0040] The fuel injector assembly may further include a valve plate 224 disposed in the first cavity 314a, an orifice 228 disposed in the nozzle 400 in contact with the valve plate 224, and a control valve 218 disposed in the fuel injector body 300 above the valve plate 224 and the orifice 228. Other configurations are possible in other embodiments of the invention.

[0041] like Figure 5 and 6 In some of the best-illustrated embodiments, the fuel injector body 300 may further define an exhaust passage 320 communicating with a first cavity 314a of the fuel injector body 300, and a low-pressure exhaust cavity 322.

[0042] More specifically, such as Figure 6 As best shown, the fuel injector body 300 may further define a radially outer circumferential surface 324, and the low-pressure discharge cavity 322 takes the form of a circumferential groove 322a, which is axially disposed on the upper seal 326 (see Figure 1). Figure 5 On the radial outer circumferential surface 324 between the lower seal 328 and the lower seal 328.

[0043] Focus on Figure 6 The first cavity 314a may be defined by a bottom surface 330 (e.g., a flat annular surface), and the discharge channel 320 is along a direction including a longitudinal axis 306 and a radial direction 310 (e.g., a radial direction including a longitudinal axis 306 and a radial direction 310). Figure 6 The hole (e.g., drilled using a conventional drill bit or electrical discharge machining) extends from the bottom surface 330 to the circumferential groove 322a in a plane forming an angle 332 with the longitudinal axis 306 in the cross-section. Other orientations and configurations are possible for the holes in other embodiments of the invention.

[0044] Next, we will refer to Figure 3 and Figure 4 This discussion concerns components such as the fuel injector body and / or nozzle, which can be supplied as replacement parts for repairing, overhauling, or modifying fuel injector assemblies.

[0045] Figure 4 The fuel injector body 300 shown may include an external interface portion 334, which includes a sealing surface 335 axially disposed between a first end 312 and a shoulder 336. More specifically, an external threaded portion 344 may be axially disposed between the sealing surface 335 and the shoulder 336.

[0046] As previously described, the first cavity 314a defines a bottom surface 330, and the outer peripheral surface 338 defines a first cavity diameter 316a. Furthermore, the sealing surface 335 may define a sealing surface diameter 340, and in some embodiments, the ratio of the sealing surface diameter 340 to the first cavity diameter 316a may range from 0.3 to 4.4. In such embodiments, the body may define a radial thickness 342 from the sealing surface 335 to the outer peripheral surface 338 ranging from 5.0 mm to 22.0 mm. This may not be the case in other embodiments of the invention.

[0047] Furthermore, in some embodiments, the first cavity 314a may define a first cavity axial depth 346 from the bottom surface 330 to the first end 312, and the ratio of the sealing surface diameter 340 to the first cavity axial depth 346 may be in the range of 0.2 to 4.4. In this case, the first cavity axial depth 346 may be in the range of 5.0 mm to 30.0 mm. In other embodiments of the invention, other configurations, dimensions, and ratios are possible.

[0048] As mentioned earlier in this article, the radially outer surface 324a can be radially outwardly disposed from the shoulder 336 defining the low-pressure discharge recess 322b (see [link]). Figure 6 The leakage channel 320a can extend from the bottom surface 330 to the low-pressure discharge recess 322b, which in turn communicates with the discharge outlet 304 (see...). Figure 5 Therefore, when a problem occurs, the high pressure can be reduced, thereby minimizing the risk of further damage to the components of the fuel injector assembly.

[0049] See Figure 3 The replacement nozzle 400 (which may be the component shown in the figure) may include a body that includes at least a portion of a stepped annular configuration defining the radial direction, the circumferential direction and the longitudinal axis, as previously described with reference to the fuel injector body 300.

[0050] The nozzle 400 may include a first longitudinal end 404 and a second longitudinal end 404a. An attachment portion 416 may be disposed at the second longitudinal end 404a, while a tip portion 418 having a spray outlet 402 may be disposed at the first longitudinal end 404.

[0051] Specifically, such as Figure 4 As best shown, the attachment portion 416 may include a fuel injector body receiving cavity 420 defining an inner circumferential surface 422 (which may include any rotating surface including conical, cylindrical, etc.), the inner circumferential surface 422 including an internal thread 424 extending from the second longitudinal end 404a, and defining a sealing receiving groove 426 axially disposed below the internal thread 424.

[0052] To provide a robust design, the attachment portion 416 may include a maximum radial wall thickness 428 (e.g., slightly above or below the sealing receiving recess 426) surrounding the circumference of the fuel injector body receiving cavity 420, and a minimum radial wall thickness 430 (e.g., at the sealing receiving recess 426) surrounding the circumference of the fuel injector body receiving cavity 420. In some embodiments, the ratio of the maximum radial wall thickness 428 to the minimum radial wall thickness 430 may be in the range of 0.12 to 17.0. In this case, the maximum radial wall thickness 428 may be in the range of 2.0 mm to 17.0 mm, while the minimum radial wall thickness 430 may be in the range of 1.0 mm to 17.0 mm. To provide a sufficient seal, the sealing receiving recess 426 may be spaced from the internal thread 424 by a minimum axial distance 432 in the range of 2.0 mm to 25.0 mm (see [link to documentation]). Figure 6 In other embodiments of the invention, other configurations, size ratios, and dimensions are possible.

[0053] Now, refer to Figure 5 and Figure 6 The discussion focuses on another embodiment of a fuel injector that provides pressure relief in the nozzle and the nozzle / fuel injector body interface.

[0054] As mentioned earlier, the fuel injector body 300 of the fuel injector assembly 200 can be disposed within the second countersunk hole 406 and the second cavity 406a of the nozzle 400, forming an interface region 244 with the nozzle 400 and a seam 246 between the fuel injector body 300 and the nozzle 400. The fuel injector body can further define a supply channel 348 communicating with the pressurized fuel chamber 215 and the common rail inlet 302 to supply fuel. Moreover, a leakage channel 320a can extend from the first cavity 314a.

[0055] like Figure 4 As best shown, the fuel injector body 300 defines a bottom surface 330 of a first cavity 314a, a leakage passage 320a may extend radially from the bottom surface 330 on one side of the longitudinal axis 306, and a supply passage 348 lies in a plane including the radial direction 310 and the longitudinal axis 306 (e.g., in...). Figure 4 In the cross section, it extends radially to the bottom surface 330 on the other side of the longitudinal axis 306.

[0056] In addition, Figure 6In this embodiment, the fuel injector body 300 may include an outer peripheral surface 339 disposed radially outward from the nozzle 400. The outer peripheral surface 339 may define a low-pressure discharge recess 322b communicating with a leakage passage 320a. A valve plate 224 may be disposed in a first cavity 314a, including an adjacent sealing surface 254 facing a bottom surface 330 of the first cavity 314a. This adjacent sealing surface 254 may define a reservoir 256 communicating with the leakage passage 320a, and a through passage 258 connecting the supply passage 348 fluidly to the pressurized fuel chamber 215 (see [link to documentation]). Figure 4 The leakage channel, through channel, and supply channel can all extend in directions inclined to the longitudinal axis and the radial direction. Furthermore, the supply channel and through channel can be inclined relative to each other (i.e., not straight relative to each other). Other configurations are possible in other embodiments of the invention.

[0057] Figure 6 In this embodiment, the leakage channel 320a may be in the form of a straight hole (e.g., cylindrical) formed in the fuel injector body 300 by machining or otherwise. Accordingly, the leakage channel 320a may define a channel diameter 350, and the first cavity 314a may define a first cavity diameter 316a (see [reference needed]). Figure 4 In some embodiments of the invention, the ratio of the first cavity diameter 316a to the channel diameter 350 can be in the range of 2.0 to 10.0. In this case, the leakage channel diameter can be in the range of 1.0 mm to 5.0 mm. In other embodiments of the invention, other ranges are possible.

[0058] Some embodiments of the fuel injector body of the present invention may also have the following features.

[0059] As previously mentioned, the fuel injector assembly 200 may further define a radial sealing receiver recess 248 along the joint 246 (see below). Figure 4 The nozzle 400 is longitudinally positioned, and the seal 250 is disposed in the radial sealing receiving groove 248. The radial sealing receiving groove may be axially positioned below the bottom surface 330 of the first cavity 314a, but this is not mandatory. In the embodiment shown in the figures, the second cavity 406a of the nozzle 400 includes a radially inner circumferential surface 422a defining the radial sealing receiving groove 248. This may not be the case in other embodiments of the invention.

[0060] Now refer to Figures 4 to 6 The discussion may provide various embodiments of the fuel injector body for replacement parts, etc., of the fuel injector assembly just described.

[0061] The fuel injector body 300 may include an external interface portion 334, which includes a sealing surface 335 axially disposed between a first end 312 and a shoulder 336. A first cavity 314a defines a bottom surface 330 and an outer peripheral surface 338, while a leakage passage 320a extends from the bottom surface 330 and communicates with the first cavity 314a.

[0062] In some embodiments, the leakage channel 320a extends in a direction inclined to the radial direction 310 and the longitudinal axis 306. In a specific embodiment, the leakage channel extends in a plane that is parallel to the radial direction and the longitudinal axis (e.g., ...). Figure 6 (in cross-section). This may not be the case in other embodiments of the invention. Figure 4 As shown, the fuel injector body 300 may further define a supply passage 348 extending into the first cavity 314a, but this is not mandatory.

[0063] In such Figure 6 In some embodiments shown, the fuel injector body 300 may include a stepped configuration comprising a side circumferential surface 324b (e.g., any surface of revolution including a conical surface, a cylindrical surface) and an external interface portion 334 spaced radially and axially away from the shoulder 336. The side circumferential surface 324b defines a low-pressure discharge recess 322b, to which a leakage passage 320a extends. More specifically, the low-pressure discharge recess 322b defines a corner 352, and the leakage passage 320a may extend to the corner 352 as shown, or to other portions of the recess, such as its bottom surface, its side surfaces, etc.

[0064] In other embodiments, the fuel injector body 300 has an external convex attachment portion 334a, which includes a sealing surface 335 axially disposed between the first end 312 and the shoulder 336.

[0065] The outer peripheral surface 338 defines the cavity diameter 316a, the sealing surface defines the sealing surface diameter 340, and in some embodiments of the invention, the ratio of the sealing surface diameter 340 to the cavity diameter 316 can be in the range of 0.3 to 4.4.

[0066] The external convex attachment portion 334a includes an external thread 344a axially disposed between the sealing surface 335 and the shoulder 336. A wall 354 is disposed circumferentially around the first cavity 314a, defining a minimum radial wall thickness 318a and a maximum axial wall height 319 (see [reference]). Figure 5 In this case, the minimum radial wall thickness 318a can be in the range of 1.0 mm to 22.0 mm, and the maximum axial wall height 319 can be in the range of 5.0 mm to 30.0 mm.

[0067] The fuel injector body and nozzle can be made of similar materials such as steel.

[0068] Industrial applicability

[0069] In practice, nozzles, fuel injector bodies, and / or fuel injector assemblies according to any embodiment described herein may be supplied, sold, manufactured, and purchased to refurbish, retrofit, or remanufacture existing fuel injector assemblies in the art. Similarly, fuel injector assemblies may be supplied, sold, manufactured, and purchased to provide new fuel injectors including such nozzles, fuel injector bodies, or fuel injector assemblies. Fuel injector bodies, nozzles, or fuel injector assemblies may be new, refurbished, remanufactured, etc.

[0070] This invention is generally applicable to fuel injectors for common rail fuel applications. Specifically, it applies to common rail fuel injectors used in compression-ignition engines. However, other applications in other types of engines and other types of fuel injectors are also within the scope of this invention.

[0071] During operation between injection events, the fuel injector assembly 200 is in a stationary configuration, as shown. In this stationary configuration, the solenoid actuator 202 is de-energized, the armature 204 is in contact with the pusher 220, and the control valve member 218 is in its closed position, in contact with the seat 222. Furthermore, in the stationary configuration, the check valve member 214 is in its downward closed position, blocking the nozzle injection outlet 402. Also, in the stationary configuration, the pressure in the pressurized fuel chamber 215 is high, allowing the rail pressure to act on the closing hydraulic surface 213 and the opening hydraulic surface 216.

[0072] The injection event is initiated by energizing the solenoid actuator 202. When this occurs, the electrode 208 magnetically attracts the armature 204. As the armature 204 begins to move toward the stator assembly 206, the pusher 220 is raised to allow the high pressure in the pressurized fuel chamber 215 to push the control valve member 218 away from the seat 222, thereby fluidly connecting the pressurized fuel chamber 215 to the low pressure of the discharge outlet 304. The movement of the armature 204 stops when the seat contacts the stop pin 210. When the pressure in the pressurized fuel chamber 215 has sufficiently decreased, the high pressure acting on the opening hydraulic surface 216 overcomes the bias spring 230 and pushes the check valve member 214 upward to initiate the injection event. When the fuel injector is in the injection configuration, the check valve component 214 is in its upward open position, the control valve component 218 is in its open position without contacting the seat 222, and the push pin 220 contacts the stop pin 210 and the armature 204, which is located at the final air gap distance away from the stator assembly 206.

[0073] During an injection event, the pressure in the nozzle and fuel injector body may be high. The embodiments discussed herein can help prevent fuel leakage at the interface between the nozzle and fuel injector body, and / or can help provide pressure relief so that the fuel injector components are not damaged if problems such as component jamming occur. In some applications, such as common rail applications, the pressure in the high-pressure passages in the nozzle and body may be high, not only during an injection event. When the ball (which may take the form of a flat geometry to form a seat as shown in the attached figure) rises, the pressure on the top of the check valve can be vented, causing a pressure imbalance that allows the check valve ball to rise, opening the tip to the check valve seat and allowing the injection event to occur.

[0074] It should be understood that the foregoing description provides examples of the disclosed components and techniques. However, it is conceivable that other embodiments of the invention may differ in detail from the foregoing examples. All references to the invention or examples thereof are intended to refer to the specific examples discussed at that point and are not intended to imply any limitation on the scope of the invention in a more general sense. All distinguishing and derogatory language regarding certain features is intended to indicate a lack of preference for those features, but does not mean that they are entirely excluded from the scope of the invention, unless otherwise specified.

[0075] Unless otherwise stated herein, the description of the range of values ​​herein is intended only as a shorthand for individually referring to each individual value falling within that range, and each individual value is incorporated into the description as if it were described individually herein.

[0076] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and assembly methods discussed herein without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art upon consideration of the description and practice of the various embodiments disclosed herein. For example, some devices may be configured and operated differently from those described herein, and certain steps of any method may be omitted, performed in a different order than specifically mentioned, or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications may be made to certain aspects or features of the various embodiments to create further embodiments, and features and aspects of the various embodiments may be added to or replaced in other features or aspects of other embodiments to provide even more further embodiments.

[0077] Therefore, this invention includes all modifications and equivalents of the subject matter described in the appended claims as permitted by applicable law. Furthermore, unless otherwise stated herein or clearly contradicted by the context, this invention covers any combination of the foregoing elements in all possible variations.

Claims

1. A fuel injector body for use with a fuel injector, the fuel injector body comprising: The body includes at least a partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction; The first end is axially arranged along the longitudinal axis, and the second end is axially arranged along the longitudinal axis. A first countersunk hole and a first cavity extending from the first end toward the second end; and The external interface portion includes a sealing surface axially disposed between the first end and the shoulder; The first cavity defines a bottom surface and an outer peripheral surface, and the body further includes a leakage channel extending from the bottom surface, the leakage channel communicating with the first cavity; The fuel injector body includes an exhaust outlet and a low-pressure exhaust groove located on the outer periphery of the fuel injector body in fluid communication with the exhaust outlet. The leakage channel extends to the low-pressure exhaust groove in a direction inclined to the radial direction and the longitudinal axis.

2. The fuel injector body of claim 1, wherein the fuel injector body further defines a supply passage extending into the first cavity.

3. The fuel injector body according to claim 2, wherein the direction in which the leakage channel extends is in the same plane as the radial direction and the longitudinal axis.

4. The fuel injector body of claim 1, wherein the body comprises a stepped configuration including side circumferential surfaces radially spaced apart from the shoulder and the external interface portion.

5. The fuel injector body of claim 4, wherein the side circumferential surface defines the low-pressure discharge groove.

6. The fuel injector body of claim 5, wherein the low-pressure discharge recess defines a corner, and the leakage passage extends to the corner.

7. A fuel injector body for use with a fuel injector, the fuel injector body comprising: The body includes at least a partially annular configuration defining a longitudinal axis, a circumferential direction, and a radial direction; The first end is axially arranged along the longitudinal axis, and the second end is axially arranged along the longitudinal axis. A first countersunk hole and a first cavity extending from the first end toward the second end; and The external convex attachment portion includes a sealing surface axially disposed between the first end and the shoulder; The first cavity defines a bottom surface and an outer peripheral surface, and the body further includes a leakage channel extending from the bottom surface, the outer peripheral surface defines a cavity diameter, the sealing surface defines a sealing surface diameter, and the ratio of the sealing surface diameter to the cavity diameter is in the range of 0.3 to 4.

4. The leakage channel extends along a direction inclined to the radial direction and the longitudinal axis, and the fuel injector body includes an exhaust outlet and a low-pressure exhaust groove located on the outer periphery of the fuel injector body in fluid communication with the exhaust outlet, the leakage channel extending to the low-pressure exhaust groove.

8. The fuel injector body according to claim 7, wherein the external convex attachment portion includes an external thread axially disposed between the sealing surface and the shoulder.

9. The fuel injector body of claim 7, wherein the external convex attachment portion includes a wall disposed around the circumference of the first cavity, defining a minimum radial wall thickness and a maximum axial wall height.

10. The fuel injector body according to claim 9, wherein the minimum radial wall thickness is in the range of 1.0 mm to 22.0 mm, and the maximum axial wall height is in the range of 5.0 mm to 30.0 mm.

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