Gas injector with optimized valve housing
By optimizing the valve housing structure, the shear stress of the weld is reduced, and the problems of valve needle wear and unstable connection in the gas injector are solved, thereby achieving reliable sealing under high clamping force.
Patent Information
- Application Number
- CN202380088361.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-23
- Filing Date
- 2023-10-17
- Publication Date
- 2025-08-01
AI Technical Summary
The existing gas injectors have excessive wear problems in the guide valve needle area, and the welds are subjected to high shear stress due to the internal force path introduced by the clamping force, which affects the connection stability.
An optimized valve housing structure is designed, including a thin-walled tubular valve housing and a sleeve-shaped support, which reduces the shear stress of the weld by optimizing the force transmission path, and uses a main body, magnet can and support with the same outer diameter and wall thickness, which is supported on the cylinder head by a radial flange.
Improves the stability of the welded connections, reduces wear, and ensures the reliability and sealing of the gas injector under high clamping force.
Smart Images
Figure CN120418533A_ABST
Abstract
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a gas injector for injecting gaseous fuel, in particular hydrogen, natural gas, etc., which has very robust and durable guiding characteristics for guiding a long valve needle of a closing element of the gas injector, and a valve housing optimized in terms of force transmission. The gas injector is particularly designed for direct injection into the combustion chamber of an internal combustion engine. BACKGROUND OF THE INVENTION
[0002] Gas injectors of different configurations are known from the prior art. A series of problems in gas injectors is that, due to the gaseous medium to be injected, lubrication cannot be carried out through the medium as in, for example, fuel injectors for injecting gasoline or diesel. This results in excessive wear during operation, especially in the area for guiding the valve needle, compared to fuel injectors for liquid fuels. In addition, due to the continuous miniaturization of internal combustion engines, a compact design is usually required.
[0003] In known gas injectors, the internal "force path" introduced by the clamping force of a clamping device, such as a clamping pliers, passes through various different components of the valve housing, which are radially offset from each other, such that the welds in the connection areas of these valve housing components are subjected to high shear stresses, so that when the clamping force is, for example, 15 kN, no allowable stress in terms of the strength of the joint connection can be expected anymore. SUMMARY OF THE INVENTION
[0004] In contrast, the gas injector for injecting gaseous fuel, in particular hydrogen, according to the invention having the features of claim 1 has the advantage that, due to the internal "force path" provided in the gas injector, the welded connection is significantly less subjected to shear stress, thereby significantly improving the stability of the welded connection. Thus, for example, a clamping force in the order of 15 kN can be regarded as insignificant.
[0005] According to the invention, this is achieved in that the gas injector has a valve housing optimized in terms of force transmission. The gas injector has: a thin-walled and tubular valve housing forming a radially outer boundary (Abschluss), which radially outwardly delimits an annular space for supplying gaseous fuel in the direction of a sealing seat; and a housing component radially inwardly delimiting the annular space. According to the invention, the housing component radially inwardly delimiting the annular space consists of an inlet-side body, a magnet can, and a support body, wherein the support body is configured as a sleeve and has an outer peripheral region and a bottom region here, and the bottom region forms a radial flange, and the support body and thus the gas injector can be supported at least indirectly on the cylinder head by means of this radial flange.
[0006] The support is adapted to transmit the axial force in an optimized manner within the gas injector according to the geometric design of the present invention, and is introduced in the installed state by the clamping force of the clamping device acting on the inlet side and against the acting direction of the supporting force of the gas injector on the cylinder head.
[0007] The dependent claims show preferred embodiments of the present invention.
[0008] Particularly advantageously, the body, the magnet can, and the support have substantially the same outer diameter over the length of the annular space. Advantageously, the body, the magnet can, and the support also have substantially the same wall thickness over the length of the annular space. In this geometric design, the welds in the respective butt joints only bear pressure, thus excluding shear stress and significantly improving the stability of the welded joints.
[0009] Preferably, the support is supported on the sealing gasket placed on the cylinder head by means of its radial flange. In order to transmit and conduct away the clamping force as best as possible and to avoid deformation or distortion of the valve housing, the radial flange of the support should have an axial wall thickness of at least 2.5 mm.
[0010] Further preferably, the gas injector has a conical seat or a ball-conical seat. Preferably, the closing element includes a sealing gasket at the end pointing towards the combustion chamber, and the sealing gasket releases one or more through openings on the sealing seat. The gas injector is preferably configured as an outward-opening injector. Thereby, a sealing seat can be provided which is perpendicular to the longitudinal direction of the gas injector in a plane.
[0011] Preferably, oil, especially synthetic oil, is used as the lubricant. Alternatively, liquid fuel, especially diesel or gasoline, is used. Further alternatively, grease is used as the lubricant. Description of the Drawings
[0012] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the drawings:
[0013] Figure 1 A schematic cross-sectional view of a gas injector according to a known embodiment is shown; and
[0014] Figure 2 A schematic cross-sectional view of a gas injector according to an embodiment of the present invention is shown. Detailed Description of the Embodiment
[0015] Below, with reference to Figure 1 and Figure 2 a gas injector 1 according to a preferred embodiment of the present invention will be described in detail. Wherein, Figure 1The gas injector 1 with a known basic structure is shown. For a better understanding of the present invention, the basic structure of the gas injector 1 is described at this injector, such that the important aspects of the present invention according to the embodiment of the gas injector 1 according to Figure 2 become particularly apparent compared to known solutions.
[0016] As Figure 1 shown, the gas injector 1 for introducing gaseous fuel includes an electromagnetic actuator 2, which moves the outwardly opening closing element 3 from the closed state to the open state. Figure 1 The closed state of the gas injector is shown here.
[0017] The electromagnetic actuator 2 includes an armature 20, which is connected to the closing element 3 by means of an armature stud 24. In addition, the electromagnetic actuator 2 also includes an inner pole 21, a coil 22, and a magnet housing 23, which ensures the magnetic circuit of the electromagnetic actuator 2.
[0018] The gas injector 1 also includes a body 7 having a gas inlet 70 through which gaseous fuel is supplied. Here, a valve housing 8 is fixed to the body 7, and the electromagnetic actuator 2 is arranged in the valve housing. A housing sleeve 19 is attached to the valve housing 8, and a sealing seat 11 is provided on the valve seat member 93 at the free end of the housing sleeve, and the closing element 3 releases or closes the flow passage for gaseous fuel on this sealing seat.
[0019] Figure 1 The electrical connection 13 is schematically shown in
[0020] which guides through the body 7 and the valve housing 8 up to the electromagnetic actuator 2. Figure 1 The reference numeral 10 denotes a reset element for the closing element 3, which is configured in the form of a helical spring in order to reset the closing element to the closed state shown in
[0021] Figure 1 The gas flow is also shown in Figure 1 as the gas path 14 through the gas injector 1. Here, the gas flow starts from the gas inlet 70 and is then redirected and guided into the annular space 80 between the valve housing 8 and the body 7. The gas flow 14 then continues to flow through the outer region of the electromagnetic actuator 2 through the downstream filter 15 up to the sealing seat 11. Accordingly, through-holes are provided in the corresponding individual components, and these through-holes
[0022] are not all shown in Figure 1 When the gas injector 1 is open, the gaseous fuel flows into the combustion chamber 100 of the internal combustion engine through the outer periphery of the electromagnetic actuator 2 and the open sealing seat 11, which is indicated by the arrow A in
[0023] The closing element 3 includes a valve needle 30 having a seating disk 30a which is arranged at the end of the closing element facing the combustion chamber. A sealing seat 11 is formed here between the seating disk 30a and the valve seat member 93 which is a cylindrical tube.
[0024] The closing element 3 further includes a first needle guide 31, a second needle guide 32 and a third needle guide 33. These three needle guides 31, 32, 33 are integrally or multi - piece constructed with the valve needle 30.
[0025] The closing element 3 further includes a disk 34 which is arranged in the axial direction X - X between the second needle guide 32 and the third needle guide 33.
[0026] The gas injector 1 further includes a closed lubricant chamber 4. The closed lubricant chamber 4 is completely or partially filled with a liquid lubricant, such as oil.
[0027] As Figure 1 shown, the lubricant chamber 4 is defined by a first flexible sealing element 51, an inner pole 21, a magnet housing 23, a guide body 18 and a second flexible sealing element 52. The first and second flexible sealing elements 51, 52 are each constructed as a folded tube or bellows.
[0028] It should be noted that, instead of bellows, the flexible sealing elements 51, 52 can also be diaphragms, hoses, etc.
[0029] As Figure 1 further shown, the second flexible sealing element 52 is fixed, for example, by a welded connection on the energy storage spring disk 41. In addition, the gas injector 1 includes an energy storage compression spring 40 which is supported on the body 7 and pre - loads the second flexible sealing element 52 via the energy storage spring disk 41. A connection hole 18a is provided in the guide body 18 such that the lubricant located in the lubricant chamber 4 is also in the region within the second flexible sealing element 52.
[0030] The first flexible sealing element 51 is directly fixed on the disk 34 on the closing element 3 and is connected to the guide sleeve 9 at the other end. The third needle guide 33 is guided within the guide sleeve 9.
[0031] Thus, the lubricant chamber 4 has two flexible sealing elements 51, 52 and an energy storage compression spring 40. The energy storage compression spring 40 exerts a certain pre - load force, such as 1×10 5A pressure Pa is applied to the lubricant located in the lubricant chamber. If during the opening process the lubricant is squeezed due to the stroke of the closing element 3 or also due to the thermal expansion or cooling of the lubricant, the overpressure / negative pressure that may occur in the interior of the lubricant chamber 4 can be balanced by the offset at the second flexible sealing element 52 in combination with the contraction of the energy storage compression spring 40. Thus, the flexible sealing element 51 is able not to apply unwanted forces acting via the bellows working surface to the closing element 3.
[0032] An armature stud 24 is also arranged in the closed lubricant chamber 4, and an armature 20 is fixed thereto. Since the lubricant chamber 4 is filled with a lubricant, such as an oil or a grease having a viscosity comparable to that of gasoline or diesel, continuous lubrication of the armature 20 is obtained. Thereby, the problem regarding the lack of lubrication of moving parts that occurs in the case of gaseous fuels in the prior art is solved.
[0033] Herein, a third needle guide 33 is also arranged in the lubricant chamber 4. For example, the third needle guide 33 is guided inside the guide sleeve 9. A return element 10 is also arranged inside the guide sleeve 9, and it is supported on the shoulder 9a of the guide sleeve 9 and on the third needle guide 33. Thus, the third needle guide 33 has two functions: namely, one is the guiding of the valve needle 30, and the other is the support of the return element 10. Herein, through-holes 33a are respectively provided in the third needle guide 33, so that the lubricant located in the lubricant chamber 4 can pass through these through-holes.
[0034] The guide sleeve 9 is connected to the first flexible sealing element 51, for example, by means of a welded connection.
[0035] Since the third needle guide 33 is arranged in the lubricant chamber 4, sufficient lubrication exists in all operating conditions of the gas injector herein, so that no wear occurs on the third needle guide during operation. In contrast, the first needle guide 31 and the second needle guide 32 are arranged in the gas path 14.
[0036] Overall, the gas injector 1 is constructed very slenderly, and during operation, no lateral force may be applied to the valve needle 30 due to the tipping moment of the return element 10 or the first flexible sealing element 51, thus ensuring that the gas injector can always be sealed in all operating conditions and can be reliably reset to the closed sealing state again even after being opened. Therefore, the wear on the needle guide can also be neglected.
[0037] A braking device 6 is also arranged in the closed lubricant chamber 4. The braking device 6 includes a brake stud 60, a brake spring 61, and a damping chamber 62. The damping chamber 62 is fluidly connected to the lubricant chamber 4.
[0038] During the reset process of the gas injector to the closed initial position, the detent pin 60 and the elastic detent element 61 are in operative connection with the closing element 3. Here, during the reset process, lubricant is extruded from the damping chamber 62 into the lubricant chamber 4 to achieve additional damping when resetting the detent pin 60 in the closed state of the gas injector. The detent pin 60 is guided in the guide body 18 here.
[0039] As Figure 1 As further shown, the damping chamber 62 is constructed directly on the detent pin 60 on the side of the detent pin 60 facing away from the sealing seat 11. The damping chamber 62 is connected to the connecting hole 18a through a throttle portion 63 (which is a small hole) and is thus connected to the main region of the lubricant chamber 4. The detent spring 61 is arranged in the spring chamber 67.
[0040] The detent pin 60 has a contact surface that is in contact with the armature pin 24. Here, in the closed state, there is a first gap 101 between the detent pin 60 and the fixed armature pin guide 25. During the opening and closing processes, the armature pin guide 25 guides the armature pin 24.
[0041] As Figure 1 As further shown, the detent spring 61 is arranged between the detent pin 60 and the guide body 18. The detent pin 60 has a flange here, which is provided with a gap from the guide body 18.
[0042] In the closed state, a first gap 101 is also constructed between the contact surface of the detent pin 60 and the armature pin guide 25. Here, the first width of the first gap 101 is smaller than the second width at the second gap 102 between the armature 20 and the inner pole 21. This ensures that the stroke of the detent pin 60 pre-tensioned in the axial direction by the compression spring 61 is smaller than the stroke of the armature 20. Thus, during the blowing-in process, sufficient fluid can flow from the lubricant chamber 4 into the damping chamber 62 via the throttle portion 63.
[0043] During the closing process, the armature pin 24 impacts the contact surface of the detent pin 60. Thereby, the detent pin 60 is pressed towards the fluid located in the damping chamber 62. Due to the throttle portion 63, the fluid cannot be immediately extruded from the damping chamber 62 but is extruded slowly, so that a damping effect can be achieved during the closing process. Thereby, excessive wear on the sealing seat 11 and the armature 20 is avoided because the closing process is damped by the reset of the detent pin 60.
[0044] The damping process is also supported by the hydraulic bonding action of the brake spring 61 and the brake stud 60 on the armature stud guide 25. Here, the damping chamber 62 can prevent cavitation from occurring in the area between the abutment surfaces of the armature stud guide 25 and the brake stud 60 during the closing process. In addition, the friction of the brake stud 60 in the guide body 18 delays the reset process and also delays the mass of the moving components to be accelerated in the entire lubricant chamber, which causes the extrusion of the lubricant in the closed lubricant chamber, resulting in additional braking during the closing process.
[0045] By selecting the diameter and / or length of the throttle part 63, the damping characteristics can be individually adjusted for the corresponding gas injector 1.
[0046] Overall, therefore, the wear on the sealing seat 11 and the closing element 3 can be effectively reduced. The so-called "closing rebound" on the sealing seat 11 can also be effectively prevented.
[0047] Figure 1 The gas injector 1 shown therein is pressure-balanced. That is, the closing element 3 is connected to the guide sleeve 9 through the first flexible sealing element 51. The average diameter of the first flexible sealing element 51 implemented as a metal bellows is equal to the diameter at the sealing seat 11, and the closing element 3 is sealed at this diameter. Thus, no extrusion force acts on the closing element 3, so that the magnetic force required to open the closing element can be kept very small, and in particular this magnetic force is independent of the pressure of the gaseous fuel.
[0048] In the installed state, the gas injector 1 is received in the receiving hole of the cylinder head 45, which is only schematically shown and shown in a sectional view. To seal the gas injector 1 relative to the cylinder head 45 of the gas internal combustion engine, a high clamping force is required. Here, the clamping force F N is applied, for example, by a clamping device (not shown), especially pliers. The application of the clamping force F N is symbolically represented by the corresponding arrow. Here, the clamping force F N is introduced at the inlet-side end of the gas injector 1, specifically on the body 7 fixed in the thin-walled valve housing 8.
[0049] These clamping forces F NMost of it is transmitted to the cylinder head 45 through an internal "force path" (the direction of which is indicated by line 50). The internal force path 50 extends here through the body 7, the magnet can 54, the inner pole 21, the guide sleeve 9, the housing sleeve 19 and the valve housing 8 up to the sealing gasket 56, which is placed on the end face of the cylinder head 45, and the gas injector 1 is supported on this sealing gasket by means of a radial flange of the valve housing 8. The above-mentioned metal components of the gas injector 1 are usually sealed and fixedly connected by means of welds here. For example, welds 57, 58 and 59 are mentioned, which fixedly connect the magnet can 54 to the inner pole 21, the guide sleeve 9 to the housing sleeve 19 and the housing sleeve 19 to the valve housing 8 respectively. High shear stresses may occur just at these welds 57, 58, 59, so that in the case of the required clamping force F N For example, in the case of 15 kN, no allowable load may occur in terms of the strength of the joint connection.
[0050] The support force F N acting against the clamping force F A is also symbolically indicated by an arrow in the cylinder head 45.
[0051] Therefore, the object of the present invention is to provide an internal force path 50 and avoid welds subject to shear stress as known in the solutions as Figure 1 shown.
[0052] Figure 2 FIG. shows a schematic cross-sectional view of a gas injector 1 according to an embodiment of the present invention, in which an optimized valve housing exists according to the present invention. Advantageously, a sleeve-shaped support body 75 for transmitting axial force is provided, which is axially supported on the magnet can 54 on the one hand and fixedly connected to the housing sleeve 19 on the other hand. The sleeve-shaped magnet can 54 and the support body 75 have substantially the same outer diameter here. In addition, the wall thicknesses of the two components are also selected to be the same or very close; in any case, the wall thicknesses of the magnet can 54 and the support body 75 are greater than the wall thickness of the thin-walled valve housing 8.
[0053] Advantageously, the structure according to the present invention with the support body 75 enables the omission of the three welds 57, 58, 59 mentioned above( Figure 1 ), which are particularly subject to shear stress in known solutions of the valve housing. In this regard, for example, the required clamping force F in the range of 15 kN NIt can be more reliably transmitted through the internal force path 50. Here, the internal force path 50 now extends through the body 7, the magnet can 54, the support 75, and the housing sleeve 19 up to the sealing gasket 56, which is placed on the end face of the cylinder head 45, and the gas injector 1 is now supported on this sealing gasket by means of the radial flange 76 of the support 75. The support 75, as a sleeve-shaped component as a whole, not only has an outer peripheral region but also has a bottom region extending at right angles thereto, which forms the radial flange 76 and is penetrated (durchgriffen) by the housing sleeve 19 in its internal opening.
[0054] The thin-walled and tubular valve housing 8 still forms the radially outer boundary part of the gas injector 1. However, by using the support 75, the valve housing 8 can be implemented in a shortened manner and terminates at the axial height of the inner pole 21 on the blowing side. Here, the valve housing 8 and the support 75 still have a small overlapping length so that gas can flow from the annular space 80 between the valve housing 8 and the body 7 or the magnet can 54 or the support 75 into the interior of the gas injector 1 via the transverse hole 90 in the support 75. The fixed connection between the valve housing 8 and the support 75 can be achieved by means of a weld seam 86, which can be applied directly below the transverse hole 90 of the support 75 and is not subjected to significant loads in the internal force path 50.
[0055] Due to the geometric design with substantially the same outer diameter and substantially the same wall thickness, the two weld seams 87, 88 between the body 7 and the magnet can 54 and between the magnet can 54 and the support 75 are only subjected to pressure loads in the corresponding butt joints, so shear stresses are excluded and the stability of the welded joints is significantly improved. A clamping force FN of the order of 15 kN, for example, can be regarded as unimportant. Therefore, the housing components radially bounding the annular space 80 are composed of the body 7 on the inlet side, the magnet can 54, and the support 75.
[0056] Advantageously, the support 75 is implemented as a turned part, and preferably martensitic steel is used as the material, such as steel No. 1.4418 and steel No. 1.4305.
[0057] The support 75 should have a radial wall thickness S1 in its outer peripheral region, and for strength reasons, this wall thickness should not be less than 1 mm at any point. In contrast, the minimum axial wall thickness S2 of the radial flange 76 of the support 75 should be 2.5 mm, and the support 75 is supported on the sealing gasket 56 by means of this flange and thus indirectly on the cylinder head 45.
Claims
1. A gas injector for injecting a gaseous fuel, in particular hydrogen, having: An electromagnetic actuator (2) having an armature (20), an inner pole (21), a magnet can (54) and a coil (22); A closing element (3) having a valve needle (30), wherein, The closing element (3) releases and closes the gas path (14) at the sealing seat (11), wherein the armature (20) is operatively connected to the closing element (3); A tubular valve housing (8) which forms the radially outer boundary portion of the gas injector (1), the tubular valve housing radially bounding an annular space (80) outwardly for supplying the gaseous fuel in the direction of the sealing seat (11); A housing member radially bounding the annular space (80) inwardly; Characterized in that The housing member radially bounding the annular space (80) is composed of an inlet-side body (7), the magnet can (54) and a support (75), wherein the support (75) is configured in a sleeve shape and has an outer peripheral region and a bottom region here, and the bottom region forms a radial flange (76), and the support (75) and thus the gas injector (1) can be supported on the cylinder head (45) at least indirectly by means of the radial flange.
2. The gas injector according to claim 1, wherein The housing member radially bounding the annular space (80) is composed only of the body (7), the magnet can (54) and the support (75).
3. The gas injector according to claim 1 or 2, characterized in that, At least one transverse hole (90) is provided in the support (75), and the gaseous fuel from the annular space (80) can flow through the transverse hole into the interior of the gas injector (1).
4. The gas injector according to claim 3, characterized in that, The valve housing (8) and the support (75) are fixedly connected, in particular by means of a weld (86), below the at least one transverse hole (90).
5. The gas injector according to one of the above claims, characterized in that, The body (7), the magnet can (54) and the support (75) have substantially the same outer diameter over the length of the annular space (80).
6. The gas injector according to one of the above claims, characterized in that, The body (7), the magnet can (54) and the support (75) have substantially the same wall thickness over the length of the annular space (80).
7. The gas injector according to one of the above claims, characterized in that, The body (7) and the magnet can (54) and the magnet can (54) and the support (75) are respectively fixedly connected by means of welds (87, 88) in corresponding butt joints.
8. The gas injector according to one of the above claims, characterized in that, The support (75) is made of martensitic steel, in particular steel No. 1.4418 and steel No. 1.4305.
9. The gas injector according to one of the above claims, characterized in that, The minimum radial wall thickness (S1) in the outer peripheral region of the support (75) is 1 mm.
10. The gas injector according to one of the above claims, characterized in that, The minimum axial wall thickness (S2) of the radial flange (76) of the support (75) is 2.5 mm.
11. The gas injector according to one of the above claims, characterized in that, The support (75) is supported on a sealing gasket (56) placed on the cylinder head (45) by means of its radial flange (76).
12. The gas injector according to one of the above claims, characterized in that, The closing element (3) is an outward-opening closing element (3).