Gas injector with solenoid actuator

Abstract

The present invention relates to a gas injector (1) comprising a solenoid actuator (2) having a coil (21) and an armature (22), a closing element (3) mechanically connected to the armature (22) and configured to open and close a through-opening (4), a return element (5) that returns the closing element (3) to a closed state after the opening process, and a sleeve (6) that is closed on the circumferential side and configured to house the closing element (3) together with the armature (22) and the return element (5). In this case, the coil (21) is located radially outward of the sleeve (6).

Description

Technical Field

[0001] The present invention relates to a gas injector, particularly a gas injector configured to directly inject gaseous fuel into the combustion chamber of an internal combustion engine.

[0002] Prior Art Gas injectors are known in the prior art in various different configurations. Based on the cost advantages and high availability of gaseous fuels, this type of gaseous fuel has become increasingly preferred in recent years. However, gaseous media make it difficult to seal the gas injector against the outside. In particular, the use of highly volatile hydrogen makes it difficult to seal the gas injector. Furthermore, hydrogen embrittles metals by mixing with them, resulting in premature material fatigue. At the same time, gas injectors require a very dynamic actuator that enables the injection of a large and precise volume of gaseous medium. This requires a high magnetic force acting on the armature. However, the control of the gas injector is significantly deteriorated by the seal that prevents leakage.

[0003] Disclosure of the Invention In contrast, the gas injector according to the present invention having the features of claim 1 has the advantage of enabling reliable sealing of the gas to be injected from the surroundings. Furthermore, at the same time, this gas injector enables a rapid and powerful opening and closing process. This is made possible by the gas injector having a solenoid actuator having a coil and an armature, according to the present invention. Furthermore, the gas injector has a closing element mechanically connected to the armature and configured to open and close a through-opening. In this case, a return element, in particular a spring, keeps the closing element closed by a return force. The coil generates a magnetic field, and this magnetic field applies a magnetic force to the armature. This magnetic force causes the armature to overcome the return force and open the closing element, thereby allowing gas to be injected through the through-opening. The gas injector further has a sleeve that is closed on the circumferential side. In this case, at least the closing element, armature and return element are arranged inside the sleeve. The coil of the solenoid actuator is mounted outside the sleeve. Thus, the sleeve allows for a simple and reliable seal of the gas injector against leaking gas. At the same time, the thin sleeve allows for dynamic control of the closing element by the solenoid actuator's coil. Furthermore, the sleeve protects components of the gas injector, such as the coil, from hydrogen embrittlement.

[0004] The dependent claims illustrate preferred improved forms of the present invention.

[0005] Preferably, the sleeve extends over the entire axial length of the gas injector. In this case, in particular, one axial end of the gas injector forms the injection end, and the other end of the gas injector forms the connection end. Thus, the gas flows along the entire length of the gas injector inside the sleeve, which is closed on the circumferential side, so that gas leakage to the side is effectively prevented.

[0006] More preferably, the gas injector has annular first and second pole disks, each having an L-shaped cross-section. These pole disks are separated from each other by an intermediate region and spaced A apart, and are arranged coaxially. This arrangement results in a U-shaped cross-section of both pole disks that opens radially outward. In this case, the U-shape has a gap space A apart. The coil windings extend inside this U-shaped cross-section. The pole disks are configured to guide the magnetic field generated by the coil and concentrate it in the gap between the first and second pole disks. The sleeve may have low magnetic permeability, weakening the transmission of the magnetic field, thereby reducing the magnetic field strength acting on the armature. Alternatively, the sleeve may be made of a ferromagnetic material with, for example, very high magnetic permeability, thereby deflecting the lines of force to pass alongside the armature, and reducing the magnetic field strength in the armature. However, by concentrating the lines of force with the pole disks, a sufficiently large magnetic force acts on the armature despite the sleeve sealing the space between the coil and the armature, allowing the armature to guide the magnetic field so that it can dynamically open and close the gas injector. Preferably, the first pole disk and the second pole disk have the same inner diameter, which corresponds to the outer diameter of the sleeve.

[0007] The axial ends of the first and / or second pole disks preferably have outward-facing chamfers. The chamfers further concentrate the magnetic field and the armature in the direction of the flattened ends of the pole disks. Thus, the magnetic field strength acting on the armature is further increased, resulting in improved dynamic switching of the gas injector.

[0008] More preferably, in the open and / or closed states, one axial end of the armature is positioned in an intermediate region between the first and second pole disks. When either the upper or lower axial end of the armature is located in the intermediate region, the magnetic field generated by the coil and concentrated by the pole disks applies a greater axial force to the armature than would be possible if neither axial end were located between the pole disks. Thus, by positioning one axial end of the armature, improved dynamics of the closing element are obtained.

[0009] Preferably, the gas injector has an axial stopper, which is made of a material having particularly high magnetic permeability and forms an axial extension of the armature. In this case, a gap exists between the closed armature and the axial stopper, and the height of this gap defines the maximum opening stroke H of the armature. The gap forms an increased magnetic resistance. Therefore, the magnetic field of the coil generates a reluctance force on the armature in the direction of the axial stopper.

[0010] Preferably, the axial distance A between the first and second pole disks is greater than the maximum opening stroke H of the armature. Therefore, it can be ensured that the axial end of the armature is always located in the intermediate region between the pole disks, and that the actuator can apply the maximum opening force to the closing element.

[0011] In a further preferred configuration of the present invention, the sleeve has a first thickness W1 in the intermediate region, which is thinner than a second thickness W2 in the axial height of the first and / or second pole disks. Thus, the sleeve is thinner in the intermediate region than in the surrounding region. By thinning the sleeve in the intermediate region, the sleeve has a reduced shielding effect on the magnetic field lines concentrated in the intermediate region by the pole disks. Thus, the local reduction in thickness can increase the magnetic field strength in the region of the armature, resulting in a faster and more powerful opening and closing process.

[0012] More preferably, the sleeve is made of a metallic material. Since metallic materials have slight permeability to gases, a metallic sleeve ensures a secure seal of the gas to the surroundings with less material required. Furthermore, metallic materials are easy to process and have good mechanical and thermal properties.

[0013] In a further preferred configuration of the present invention, the sleeve is made of a ferromagnetic material, particularly a soft magnetic material. Since the ferromagnetic material has high magnetic permeability, the magnetic field is deflected along the sleeve. The magnetic field is concentrated by the magnetic pole disk, so that despite the deflection of the magnetic field, a sufficiently strong magnetic field exists in the region of the armature to dynamically manipulate the armature.

[0014] Preferably, the armature is a rotationally symmetrical object with a through-hole. The through-hole allows for efficient gas guidance through the gas injector and minimal pressure loss, enabling a large injection volume in a short time. The rotationally symmetrical shape with a through-hole means that more material is present radially outward from the axis of rotation, i.e., closer to the coil, so the magnetic field generated by the coil can act directly on the armature, generating a higher force.

[0015] More preferably, the gas injector is configured to inject hydrogen.

[0016] The present invention further relates to a gas internal combustion engine comprising at least one gas injector according to the present invention, wherein the gas injector directly injects a gaseous medium into the combustion chamber of the gas internal combustion engine.

[0017] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic cross-sectional view showing a gas injector according to a preferred embodiment of the present invention. [Figure 2] This is a schematic enlarged partial cross-sectional view showing the gas injector shown in Figure 1.

[0019] Embodiments of the present invention A gas injector 1 according to a preferred embodiment of the present invention will be described in detail below with reference to Figures 1 and 2.

[0020] As can be seen from Figure 1, the gas injector 1 has a sleeve 6 that is closed on the circumferential side. The sleeve 6 extends along the entire length of the gas injector, from the injection end 61 to the connection end 62. The sleeve is rotationally symmetric about axis XX.

[0021] The gas injector is operated by a solenoid actuator 2. The solenoid actuator 2 has a coil 21 and an armature 22. A closing element 3 is connected to the armature 22, and the closing element 3 is configured to open and close the through-opening 4.

[0022] The armature 22 is preferably made of a material having high magnetic permeability. The closing element 3 is released when the coil 21 is energized to generate a magnetic field. The magnetic field acts a magnetic force on the armature 22, causing the armature 22 to move axially together with the closing element 3, opening the through-opening 4. When the through-opening 4 is opened, gas flows from the end 62 on the connection side through the through-opening 4, past the armature 22 and the closing element 3, into the combustion chamber 8.

[0023] The return element 5 maintains the closing element 3 in the closed state shown in Figure 1, and after the opening process, returns the closing element 3 to the closed state again.

[0024] The armature 22, closing element 3, and return element 5 are located inside the sleeve 6 and surrounded by the flow of gas to be injected. The coil 21 of the solenoid actuator 2 is located outside the sleeve 6 and is protected from the gas. In this case, the coil 21 is wound around the sleeve 6.

[0025] The armature 22 is a rotationally symmetrical component with a through-opening, positioned coaxially with respect to the sleeve 6 and located within the sleeve 6. In this case, the outer diameter of the armature 22 is approximately equal to the inner diameter of the sleeve 6, and a clearance fit is established between the sleeve 6 and the armature 22, so that the armature 22 can move within the sleeve 6 with as little resistance as possible. The armature 22 is tapered towards the blowing end 61 and has multiple holes, so that gas can flow towards the closing element both inside and outside the armature.

[0026] A first magnetic pole disk 7a and a second magnetic pole disk 7b are positioned between the coil 21 and the sleeve 6. The first magnetic pole disk 7a is positioned towards the end 62 on the connection side, and the second magnetic pole disk 7b is positioned towards the end 61 on the blowing side. In this case, the inner diameters of the first magnetic pole disk 7a and the second magnetic pole disk 7b correspond to the outer diameter of the sleeve 6 in the overlap region.

[0027] The magnetic pole disks 7a; 7b are arranged annularly around the sleeve 6 and each have an L-shaped cross section. In this case, one side is arranged parallel to the sleeve 6 and the other side is arranged perpendicular to the sleeve 6. The ends of each of the sides of the first magnetic pole disk 7a and the second magnetic pole disk 7b that are arranged parallel to the sleeve 6 form the axial ends 73. The axial end 73 of the first magnetic pole disk 7a and the axial end 73 of the second magnetic pole disk 7b are arranged to face each other. An intermediate region 72 exists between the first magnetic pole disk 7a and the second magnetic pole disk 7b. The intermediate region 72 separates the magnetic pole disks 7a and 7b from each other by a certain interval A.

[0028] FIG. 2 shows the gas injector 1 shown in FIG. 1 in a schematic enlarged partial cross-sectional view. This partial cross-sectional view shows the intermediate region 72 together with the sleeve 6, the armature 22, the return element 5, the first magnetic pole disk 7a, the second magnetic pole disk 7b, and the coil 21.

[0029] The first magnetic pole disk 7a and the second magnetic pole disk 7b each have a radially outward chamfer 71 at their respective axial ends 73. The magnetic pole disks are preferably made of a material having high magnetic permeability such as, for example, an iron alloy. The magnetic pole disks 7a; 7b focus the lines of force of the magnetic field generated by the coil 21 and concentrate this between the axial ends 73 of the intermediate region 72.

[0030] The sleeve 6 has a reduced first wall thickness W1 between the axial ends 73 of the magnetic pole disks 7a; 7b compared to the thick second wall thickness W2 at the axial height of the first magnetic pole disk 7a and the axial height of the second magnetic pole disk 7b. The reduced first wall thickness W1 improves the permeability of the sleeve 6 to the magnetic field, so that a magnetic field strength as high as possible is generated in the region of the armature 22.

[0031] Figure 2 shows the armature 22 of the gas injector 1 in a closed state. The armature 22 has a maximum opening stroke H defined by an axial stopper 9. The axial stopper 9 is preferably made of a material with high magnetic permeability. The axial end of the armature 22 on the connection side is located between the axial ends 73 of the pole disks 7a;7b, whether in the open or closed state. The magnetic field generated by the coil 21 flows through the second pole disk 7b, then through the sleeve 6 and the armature 22. The magnetic field then bridges the gap 10 between the armature 22 and the axial stopper 9, and then flows from the axial stopper 9 through the sleeve 6 to the first pole disk 7a. Alternatively, the magnetic field may be directed in the opposite direction.

[0032] The magnetic resistance due to the gap 10 generates a reluctance force on the armature 22 in the direction of the axial stopper 9, so the gap 10 closes and the magnetic resistance decreases.

[0033] The high magnetic field strength between the magnetic pole disks 7a and 7b, along with the reduced first thickness W1, makes it possible to use a sleeve 6 made of a metallic or ferromagnetic material that significantly reduces the permeability of the magnetic field into the internal space of the sleeve 6. This is because the magnetic field strength is still large enough to dynamically manipulate the armature 22 with the closing element 3.

Claims

1. A gas injector (1), A solenoid actuator (2) having a coil (21) and an armature (22), A closing element (3) is mechanically connected to the armature (22) and configured to open and close the through opening (4), A return element (5) that returns the closing element (3) to the closed state after the opening process, A sleeve (6) that is closed on the circumferential side, and is configured to house the closing element (3) inside together with the armature (22) and the return element (5), and It has, The coil (21) is positioned radially outward of the sleeve (6). Gas injector (1).

2. The gas injector (1) according to claim 1, wherein the sleeve (6) extends over the entire axial length of the gas injector (1).

3. The gas injector (1) according to claim 1 or 2, comprising an annular first magnetic pole disk (7a) and an annular second magnetic pole disk (7b), each having an L-shaped cross-section, wherein the first magnetic pole disk (7a) and the second magnetic pole disk (7b) are separated from each other by an intermediate region (72) and are arranged coaxially with a distance (A) between them, so that the two magnetic pole disks (7a; 7b) form a U-shape that opens radially outward.

4. The gas injector (1) according to claim 3, wherein the axial end (73) of the first magnetic pole disk (7a) and / or the second magnetic pole disk (7b) has a radially outward chamfered portion (71).

5. The gas injector (1) according to claim 3 or 4, wherein, in the open and / or closed state, one axial end of the armature (22) is positioned in the intermediate region (72) between the first pole disk (7a) and the second pole disk (7b).

6. The gas injector (1) according to any one of claims 3 to 5, wherein the axial distance (A) between the first pole disk (7a) and the second pole disk (7b) is greater than the maximum opening stroke (H) of the armature (22).

7. The gas injector (1) according to any one of claims 3 to 6, wherein the sleeve (6) has a first thickness (W1) in the intermediate region (72), and the first thickness (W1) is thinner than the second thickness (W2) in the axial height of the first pole disk (7a) and / or the second pole disk (7b).

8. The gas injector (1) according to any one of claims 1 to 7, wherein the sleeve (6) is manufactured from a metal material.

9. The gas injector (1) according to any one of claims 1 to 8, wherein the sleeve (6) is ferromagnetic.

10. The gas injector (1) according to any one of claims 1 to 9, wherein the armature (22) is a rotationally symmetrical object having a through-opening along the axis of rotation (X-X).

11. The gas injector (1) according to any one of claims 1 to 10, wherein the gas injector (1) is configured to inject hydrogen.

12. A gas internal combustion engine having a gas injector (1) according to any one of claims 1 to 11, wherein the gas injector (1) directly injects into the combustion chamber (8) of the gas internal combustion engine.

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