Pre-chamber element, ignition device, and method for assembling the ignition device

Abstract

The present invention relates to an ignition device (1) including a pre-chamber element (2) having a main body (3) and a pre-chamber cover (4) forming a pre-chamber (5), the main body (3) having an opening (6) for receiving a spark plug (15) and a fastening portion (9) for placement in an assembly channel (10) in a cylinder head (11) or a cylinder head sleeve (12), and a transfer passage (7) formed on the main body (3) and / or the pre-chamber cover (4), the pre-chamber element (2) having an outlet opening (8) of the transfer passage (7) located at least partially outside a virtual three-dimensional body (23) defined by a geometric projection of a minimum cross section (13) of the assembly channel (10) along a longitudinal axis (14) of the assembly channel (10), and a method for assembling the ignition device (1) including the pre-chamber element (2) and the cylinder head sleeve (12) and / or the cylinder head (11).

Description

[Technical Field]

[0001] The present invention relates to an auxiliary chamber element for an ignition device, having a main body and an auxiliary chamber cover, wherein the main body and the auxiliary chamber cover form an auxiliary chamber, the main body has an opening for receiving a spark plug and a fastening portion for being placed in an assembly channel of a cylinder head or a cylinder head sleeve, and a transfer passage is formed in the main body and / or the auxiliary chamber cover.

[0002] Furthermore, the present invention relates to an ignition device having a pre-chamber element. Additionally, the present invention relates to a method for assembling an ignition device. [Background technology]

[0003] Pre-chamber ignition is known in practice and ensures improved combustion of lean fuel-air mixtures, for example in the case of spark-ignition engines. Purely by way of example, attention is drawn to EP-A-3453856. It describes an ignition device having a cylinder head, a spark plug and a pre-chamber element ("support element"). The pre-chamber element is mounted in an assembly channel ("seat") in the cylinder head and projects into the main combustion chamber. The auxiliary chamber element has a plurality of radially oriented transfer passages on the same side as the main combustion chamber. The spark plug is inserted into an opening in the pre-chamber element on the side facing away from the main combustion chamber and closes the pre-chamber in the pre-chamber element.

[0004] EP 2977586 A1 and US 2012 / 0103302 A1 each describe an ignition device having a pre-chamber element and a spark plug holder connected to one another. The pre-chamber element is disposed within an assembly channel in the cylinder head. The spark plug holder is designed to accommodate a fuel injector in addition to the spark plug.

[0005] The pre-chamber elements of known designs are usually mounted in the center of the main combustion chamber from the side of the cylinder head facing away from the main combustion chamber. This makes it possible to replace them without disassembling the cylinder head. In conventional configurations, the auxiliary chamber elements cannot penetrate into the main combustion chamber.

[0006] A problem with known pre-chamber elements is that the design of the transfer passage and the ignition-flame profile achieved by this means do not ensure sufficiently good ignition and combustion of the fuel-air mixture. The design freedom for the dimensions of the antechamber elements and therefore the arrangement of the transfer passages is further limited by the minimum cross section of the assembly channel, since the antechamber elements must pass through this assembly channel during assembly. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent Application Publication No. 3453856 [Patent Document 2] European Patent Application Publication No. 2977586 [Patent Document 3] US Patent Application Publication No. 2012 / 0103302 Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the invention to configure and further develop a pre-chamber element of the type mentioned at the outset in order to improve the ignition and combustion of the fuel-air mixture. Further, an ignition device and a method for assembling such an ignition device are specified. [Means for solving the problem]

[0009] The object of the invention is achieved by the features of claim 1. That is, the present invention provides an auxiliary chamber element for an ignition device, having a main body and an auxiliary chamber cover, wherein the main body and the auxiliary chamber cover form an auxiliary chamber, the main body having an opening for receiving a spark plug and a fastening portion for being placed in an assembly channel of a cylinder head or a cylinder head sleeve, and at least one transfer passage formed in the main body and / or the auxiliary chamber cover, the auxiliary chamber element being characterized in that at least one outlet opening of the at least one transfer passage is located at least partially outside an imaginary three-dimensional body defined by the geometric projection of the smallest cross section of the assembly channel along the longitudinal axis of the assembly channel.

[0010] According to the present invention, the ignition and combustion characteristics are critically determined by the spatial location of the ignition flame. This pilot flame then passes through a transfer passage into the main combustion chamber where it initiates combustion. The exit opening of the transfer passage is therefore the initiation point (ignition point) of combustion within the main combustion chamber and has a decisive influence on flame propagation and the speed at which combustion occurs. Furthermore, it also affects the efficiency of the process and the formation of pollutants during combustion.

[0011] According to the invention, combustion in the main combustion chamber can be improved and accelerated in a simple manner by locating the outlet openings further outside the smallest cross section of the assembly channel. This is achieved by making the area of ​​the antechamber cover larger than the smallest cross section of the assembly channel. At this time, the auxiliary chamber element is installed from the side of the cylinder head facing the main combustion chamber. The location of the outlet opening of the transfer passage is therefore independent of the smallest cross section of the assembly channel. As a result, compared to previous solutions, one or more outlet openings can be positioned much further, at least partially outside the imaginary three-dimensional body indicated by the geometric projection of the smallest cross section of the assembly channel along the longitudinal axis of the assembly channel. This includes the case where the center point of at least one outlet opening is located outside this imaginary three-dimensional body.

[0012] The term "protrusion" in the context of the present disclosure corresponds to its meaning in geometric shapes and denotes an increase in, for example, a planar dimension of an element. In this process, a virtual three-dimensional body is created by parallel displacement of a surface along a line of theoretically arbitrary length. In this case, the surface is the smallest cross section and in this case the line is the longitudinal axis of the assembly channel. Here, the projection is of essentially unlimited length in both axial directions.

[0013] In the following, an assembly channel having a circular cross section and a central axis is considered. Therefore, claim 1 relates to an antechamber element according to the preamble, in which the maximum distance of the outlet opening of at least one transfer passage from the central axis of the assembly channel is greater than the minimum radius of the assembly channel.

[0014] The fastening portion of the main body of the sub-chamber element may then have a region with a cylindrical side surface and / or a region with a conical side surface. The cylindrical side can be the side or part of the side of a general cylinder having any base area. Furthermore, the cylinder can be a right cylinder or an oblique cylinder. In the case of an oblique cylinder, the line connecting the center points of the bases is not perpendicular to the bases. The conical side can be the side or part of the side of a cone having any base area. Like the cylinder, the cone can be a right circular cone or an oblique circular cone. In the case of this oblique cylinder, the line connecting the apex of the cone and the center point of the base is not perpendicular to the base. Furthermore, the base has a circular or oval shape. Such a shape of the fastening portion allows for various fastening possibilities and at the same time a transition area for expanding the antechamber element in the direction of the antechamber cover.

[0015] The antechamber cover may have a geometric shape that deviates from a circular shape. The elliptical cover shape makes it possible to achieve a desired spacing of the outlet openings along the first long semi-axis. At the same time, the second, shorter half-axis makes it possible to realize an antechamber element with a space-saving design.

[0016] In order to improve the ignition behavior, it may be appropriate to provide a fuel injector that projects into the pre-chamber, if necessary. To this end, additional openings may be formed in the body for receiving fuel injectors.

[0017] The auxiliary chamber element is formed by a main body and an auxiliary chamber cover. The design can be two-piece or one-piece. In the two-piece configuration, the antechamber cover may be positively and / or non-positively and / or physically connected to the main body. Welded joints are particularly suitable. One advantage of this two-piece configuration is that it allows for greater freedom in design. Another advantage of the two-piece construction is that different materials can be used for the body and the antechamber cover. The body may for example be made from a material with high thermal conductivity, in particular at least 50 W / mK, preferably at least 100 W / mK (for example a copper alloy). Alternatively or additionally, the antechamber cover is manufactured from a highly heat and chemical resistant material (eg, a nickel alloy), for example. The one-piece construction of the pre-chamber element allows for particularly simple and cost-effective production, since it makes it possible to dispense with expensive joining of individual parts. In particular, the antechamber elements can be manufactured by a forming process which is a matter of extrusion or deep drawing.

[0018] Depending on the design configuration of the engine, the assembly channel or the body arranged at least partially in the assembly channel is advantageously arranged eccentrically with respect to the pre-chamber cover. In that case, the body has, for example, a region with a flank of an oblique truncated cone. Alternatively, the antechamber cover may be arranged eccentrically relative to the body, for example having a region with a right cylindrical side and / or a conical side.

[0019] Furthermore, in order to improve ignition and combustion behavior, the center points of the at least two outlet openings lie on a common circle or a common ellipse. Such an arrangement of the outlet openings ensures an advantageous and uniform combustion in the main combustion chamber.

[0020] Furthermore, the object of the invention is achieved by an ignition device having the features of claim 9. The ignition device has an auxiliary chamber element according to any one of claims 1 to 8, and a cylinder head sleeve and / or a cylinder head, an assembly channel being formed in the cylinder head sleeve or the cylinder head, and a fastening portion of the auxiliary chamber element being arranged in the assembly channel.

[0021] According to the invention, the pre-chamber element is arranged and fastened as a single component in the assembly channel of the cylinder head. In this case, the auxiliary chamber element is installed from the side of the main combustion chamber. During maintenance work, for example changing a spark plug, the pre-chamber element can remain in the cylinder head and does not have to be removed. The auxiliary chamber element is disposed and fastened within a cylinder head sleeve, which is further disposed within the cylinder head. This allows the installation and removal of the pre-chamber elements from the side of the cylinder head facing away from the main combustion chamber. The cylinder head does not need to be removed during this process. Additionally, the cylinder head sleeve allows for easy conversion of the cylinder head to use the pre-chamber element.

[0022] The assembly channel has a minimum cross section to receive the fastener portion. The part of the assembly channel in which this fastening part is located can then be of cylindrical design, formed for example by a drilled hole. In this case, the assembly channel has its smallest cross section in this section.

[0023] The fastening portion is then further advantageously used for positively and / or non-positively and / or physically fastening the sub-chamber element in the assembly channel. For example, if the fastening part has a region with a cylindrical flank, a threaded joint or a shrink fit joint is advantageous. In the case of a threaded joint, the external threads may be located within this region and the internal threads may be located on the corresponding inner surface of the assembly channel. If the fastening part has a region with a conical flank, for example, it is advantageous to implement a conical joint. Furthermore, the antechamber elements can be fastened into the assembly channel using, for example, clamp joints.

[0024] Additionally, spark plugs and / or fuel injectors may be provided. In this case, the spark plug and / or fuel injector protrudes at least partially into the pre-chamber element through an opening provided in the body. The spark plug makes it possible to ignite the fuel-air mixture in the pre-chamber. For example, the spark plug may be a conventional type spark plug without a sub-chamber. These generally have advantages over pre-chamber spark plugs and can reduce maintenance costs. Additionally, for example, the pre-chamber element functions as the ground electrode of a suitable spark plug. Additional fuel injectors can further improve ignition.

[0025] The spark plug and / or the fuel injector are positively and / or non-positively and / or materially fastened in the pre-chamber element. For this purpose, a threaded joint is suitable. The threaded joint is releasable, allowing for easy replacement of the spark plug or fuel injector. A clamp or cone joint allows for quick assembly. Shrink fit joints are also contemplated.

[0026] The pre-chamber element or ignition device of the present invention is suitable for use in, for example, stationary gas engines. Use in non-stationary spark ignition engines is further contemplated, namely due to the ignition characteristics achieved by the placement of the transfer passage. However, use is not limited to the above-mentioned types of engines, but is also contemplated for other suitable engines.

[0027] The object of the invention is further achieved by a method for assembling an ignition device having the features of claim 14. The method for assembling an ignition device according to any one of claims 9 to 13 includes the steps of: a method step of inserting the auxiliary chamber element into the assembly channel of the cylinder head from the side of the cylinder head facing the main combustion chamber, or into the assembly channel of the cylinder head sleeve before or after inserting the cylinder head sleeve into the cylinder head; the method steps of inserting a spark plug and / or a fuel injector into the pre-chamber element; Includes:

[0028] According to the present invention, with regard to the assembly of the ignition device, the above-described design of the pre-chamber element and the assembly channel allows the pre-chamber element to be inserted into the assembly channel of the cylinder head only from the side of the cylinder head facing the main combustion chamber. Therefore, during the assembly process of the ignition device, the pre-chamber element is inserted into the assembly channel of the cylinder head. When a cylinder head sleeve is used, the sub-chamber element is inserted into the assembly channel of the cylinder head sleeve before or after the cylinder head sleeve is inserted into the cylinder head. The cylinder head sleeve is inserted into the cylinder head from the side of the cylinder head facing the main combustion chamber or from the side facing away from the main combustion chamber. Furthermore, if the ignition device has a spark plug and / or a fuel injector, these are inserted into the pre-chamber element from the side of the cylinder head facing away from the main combustion chamber.

[0029] There are various possibilities for configuring and further developing the teachings of the present invention in an advantageous manner. For this purpose, reference is made, on the one hand, to the claims following the independent claims and, on the other hand, to the following description of embodiments of the invention with reference to the drawings, in which: Further developments will also generally be described in conjunction with the description of embodiments of the invention with reference to the drawings. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to a first embodiment of the present invention; [Figure 2] 10 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to another embodiment of the present invention; FIG. [Figure 3] 10 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to another embodiment of the present invention; FIG. [Figure 4] 10 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to another embodiment of the present invention; FIG. [Figure 5] 10 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to another embodiment of the present invention; FIG. [Figure 6] 10 is a schematic cross-sectional view showing an ignition device having a sub-chamber element according to another embodiment of the present invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] FIG. 1 shows an ignition device 1 according to a first embodiment of the present invention. The ignition device 1 is disposed within an engine having a cylinder 19 , a piston 18 and an engine valve 20 . The ignition device 1 comprises a pre-chamber element 2 according to the invention, into which a spark plug 15 is inserted, and a cylinder head 11 . Here, the spark plug 15 is designed as a conventional spark plug with a wire ground electrode. However, other forms of embodiment of the spark plug 15 are possible. The pre-chamber element 2 is fixed in an assembly channel 10 in the cylinder head 11 and protrudes partially into the main combustion chamber 17 . In the ignition device 1 of the first embodiment, the sub-chamber element 2 is inserted from the side of the cylinder head 11 facing the main combustion chamber 17.

[0032] The pre-chamber element 2 comprises a body 3 having an opening 6 for receiving a spark plug 15 and a pre-chamber cover 4 . These form the sub-chamber 5. The antechamber cover 4 is connected to the main body 3 by a welded seam 21 . A radially extending transfer passage 7 having an outlet opening 8 towards the main combustion chamber 17 is arranged in the pre-chamber cover 4 .

[0033] The fastening portion 9 has an area with a cylindrical side and a circular cross section, and an area with a conical side. This conical region forms the transition from the cylindrical part of the main body 3 to the antechamber cover 4 . In this first embodiment, the fastening of the sub-chamber element 2 in the assembly channel 10 via the fastening portion 9 is performed by means of a shrink-fit joint.

[0034] The assembly channel 10 then has a minimum cross section 13 in the region of the cylindrical portion of the body 3 . An imaginary three-dimensional body 23 such as a cylinder is shown by the geometric projection of this smallest cross section 13 along the longitudinal axis 14 of the assembly channel 10 . In this first embodiment, all outlet openings 8 of the transfer passages 7 are located outside this imaginary three-dimensional body 23 .

[0035] FIG. 2 shows another embodiment of an ignition device 1 according to the invention, which comprises a pre-chamber element 2, a spark plug 15 and a cylinder head 11. In this case, the pre-chamber element 2 is of one-piece design. Adjacent to the fastening portion 9 and the cylindrical region of the antechamber cover 4, the assembly channel 10 also has a circular shape. In this embodiment, the center point of the outlet opening 8 of at least one transfer passage 7 is located outside the imaginary three-dimensional body 23 indicated by the projection of the smallest cross section 13 along the longitudinal axis 14 of the assembly channel 10. In this case, the three-dimensional body 23 has a cylindrical shape with a radius a.

[0036] In other words, in this case, the distance b between the center point of the outlet opening 8 of the at least one transfer passage 7 and the central axis of the assembly channel 10 is greater than the smallest radius a of the assembly channel 10 .

[0037] Furthermore, FIG. 3 shows an ignition device 1 according to an embodiment of the invention, which comprises a pre-chamber element 2, a spark plug 15 and a cylinder head 11. The assembly channel 10 and the antechamber cover 4 in FIG. 2 have a circular shape. In this embodiment, the fastening of the antechamber element 2 in the assembly channel 10 is carried out by means of a threaded joint. The fastening part 9 has an external thread 22 in an area with a cylindrical flank. A corresponding internal thread is located in the assembly channel 10 in this area. In this embodiment too, the outlet opening 8 is located outside the virtual three-dimensional body 23 .

[0038] FIG. 4 shows another embodiment. The illustrated ignition device 1 according to the invention comprises a pre-chamber element 2, a spark plug 15 and a cylinder head 11, the pre-chamber cover 4 and the body 3 being arranged eccentrically with respect to each other. Here, the body 3 has a region with a flank of an oblique truncated cone and a flank of a right cylinder, in each case with a circular base. The auxiliary chamber cover 4 has a circular shape. Therefore, the central axis of the cylindrical portion of the main body 3 and the central axis of the sub-chamber cover 4 are arranged to be offset from each other. The region of the body 3 with the conical flanks acts as a transition region between the cylindrical portion of the body 3 and the antechamber cover 4 . The outlet opening 8 is located at least partially outside the virtual three-dimensional body 23 (in the cross-sectional view, the outlet opening 8 on the right) or is located completely outside the virtual three-dimensional body 23 (in the cross-sectional view, the outlet opening 8 on the left).

[0039] FIG. 5 shows another embodiment of the ignition device 1 according to the invention, which comprises the pre-chamber element 2 according to the invention according to FIG. 2, a cylinder head sleeve 12, a spark plug 15 and a cylinder head 11. The cylinder head sleeve 12 has an assembly channel 10 for arranging the sub-chamber element 2 and is arranged in the cylinder head 11 . The cylinder head sleeve 12 is inserted into the cylinder head 11 from the side opposite to or facing the main combustion chamber 17 . The imaginary three-dimensional body 23 is formed by the projection of the smallest cross section 13 of the assembly channel 10 , which in this case is arranged in the cylinder head sleeve 12 . The outlet opening 8 is therefore located outside the virtual three-dimensional body 23 .

[0040] FIG. 6 shows an ignition device 1 according to another embodiment of the present invention. Apart from the spark plug 15 , a fuel injector 16 is additionally arranged in the pre-chamber element 2 and projects into the pre-chamber 5 . The assembly channel 10 and the antechamber cover 4 in FIG. 2 have a circular shape. In either case, the body 3 of the pre-chamber element 2 has an opening 6 for receiving a spark plug 15 and a fuel injector 16 . In this embodiment, the outlet opening 8 is at least partially located outside the virtual three-dimensional body 23 .

[0041] To avoid repetition, attention is directed to the entire description and the appended claims for further advantageous configurations of the ignition device according to the invention.

[0042] Finally, the above-described embodiments of the ignition device of the present invention serve merely to illustrate the teachings, but are not limiting. [Explanation of symbols]

[0043] 1...Ignition device 2. Pre-chamber element 3 Main unit 4. Antechamber cover 5...Antechamber 6 Opening 7...Transfer passage 8...Exit opening 9...Connection part 10 Assembly Channel 11 Cylinder head 12 Cylinder head sleeve 13...Minimum cross section 14 Longitudinal axis 15 Spark plug 16...fuel injector 17 Main combustion chamber 18 Piston 19 Cylinder 20 Engine valve 21 Welded seam 22 Male thread 23 Virtual 3D body

Claims

1. An ignition device (1) having a pre-chamber element (2) including a main body (3) and a pre-chamber cover (4), the main body (3) and the pre-chamber cover (4) forming a pre-chamber (5), the main body (3) having an opening (6) for receiving a spark plug (15) and a fastening portion (9) for being disposed in an assembly channel (10) in a cylinder head (11) or a cylinder head sleeve (12), and a transfer passage (7) formed in the main body (3) and / or the pre-chamber cover (4), 1. An assembly channel element according to claim 1, wherein the outlet opening (8) of said transfer passage (7) is located at least partially outside a virtual three-dimensional volume (23) that is defined by a geometric projection of a smallest cross section (13) of said assembly channel (10) along a longitudinal axis (14) of said assembly channel (10).

2. 2. The auxiliary chamber element (2) according to claim 1, characterized in that the centre point of the outlet opening (8) is located outside the virtual three-dimensional body (23).

3. 3. The sub-chamber element (2) according to claim 1 or 2, characterized in that the fastening portion (9) has a region with a cylindrical flank and / or a region with a conical flank.

4. 4. An antechamber element (2) according to any one of claims 1 to 3, characterized in that the antechamber cover (4) has a geometric shape that deviates from a circular shape, preferably has an elliptical shape.

5. 5. The pre-chamber element (2) according to any one of claims 1 to 4, characterized in that an opening (6) for receiving a fuel injector (16) is formed in the body (3).

6. 6. An antechamber element (2) according to any one of claims 1 to 5, characterized in that the main body (3) and the antechamber cover (4) are of one-piece design or that the main body (3) and the antechamber cover (4) are welded to each other and are positively and / or non-positively and / or materially connected to each other.

7. 7. An antechamber element (2) according to any one of claims 1 to 6, characterized in that the main body (3) and the antechamber cover (4) are arranged eccentrically with respect to each other.

8. 8. An auxiliary chamber element (2) according to any one of claims 1 to 7, characterized in that the centre points of at least two of said outlet openings (8) lie on a common circle or a common ellipse.

9. An ignition device (1) comprising an auxiliary chamber element (2) according to any one of claims 1 to 8 and a cylinder head sleeve (12) and / or a cylinder head (11), The assembly channel (10) is formed in the cylinder head sleeve (12) or the cylinder head (11), An ignition device (1), characterized in that the fastening portion (9) of the sub-chamber element (2) is arranged in the assembly channel (10).

10. 10. Ignition device (1) according to claim 9, characterized in that the assembly channel (10) has a minimum cross section (13) for receiving the fastening part (9).

11. 11. Ignition device (1) according to claim 9 or 10, characterized in that the fastening part (9) is used for positively and / or non-positively and / or physically fastening the sub-chamber element (2) in the assembly channel (10) by means of a threaded joint, a shrink-fit joint, a clamp joint or a conical joint.

12. Ignition device (1) according to any one of claims 9 to 11, characterized in that the spark plug (15) and / or fuel injector (16) is provided.

13. 13. The ignition device (1) according to claim 12, characterized in that the spark plug (15) and / or the fuel injector (16) are positively and / or non-positively and / or materially fastened in the pre-chamber element (2) by means of a threaded joint, a shrink-fit joint, a clamp joint or a conical joint.

14. A method for assembling the ignition device (1) according to any one of claims 9 to 13, comprising the steps of: a method step of inserting the auxiliary chamber element (2) into the assembly channel (10) of the cylinder head (11) from the side of the cylinder head (11) facing the main combustion chamber (17) or into the assembly channel (10) of the cylinder head sleeve (12) before or after inserting the cylinder head sleeve (12) into the cylinder head (11); - a method step of inserting said spark plug (15) and / or fuel injector (16) into said sub-chamber element (2); A method for assembling an ignition device (1), comprising:

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