Pre-chamber ignition device for internal combustion engine, in particular of motor vehicle, and internal combustion engine, in particular for motor vehicle

Abstract

The invention relates to a pre-chamber ignition device (7) for an internal combustion engine (1), comprising: a pre-chamber (8); a plurality of overflow openings (9), via which the pre-chamber (8) is fluidically connected to a combustion chamber (2) of the internal combustion engine (1), and at least part of a mixture comprising fuel and air can be introduced from the combustion chamber (2) into the pre-chamber (8); and a spark plug (10) having an ignition electrode (11), by means of which at least one ignition spark can be generated in the pre-chamber (8) between the ignition electrode (11) and a corresponding ground electrode (12) for igniting the part introduced into the pre-chamber (8) via an overflow opening (9), a spark plug (10) having an ignition electrode (11) and a ground electrode (12) are configured as structurally separated members.

Description

Technical Field

[0001] The invention relates to a pre-chamber ignition device for an internal combustion engine, in particular for a motor vehicle, according to the preamble of claim 1. The invention also relates to an internal combustion engine, in particular for a motor vehicle, comprising at least one such pre-chamber ignition device. Background Art

[0002] DE102016206992A1 discloses a pre-chamber spark plug comprising a housing, an ignition electrode, and a ground electrode. US8839762B1 discloses a system for igniting a mixture in an internal combustion engine. DE102018008093A1 discloses a pre-chamber spark plug for a combustion chamber of an internal combustion engine. Furthermore, DE102020106397A1 discloses a reciprocating piston internal combustion engine with external ignition, comprising a pre-chamber ignition system. Summary of the Invention

[0003] The object of the present invention is to provide a pre-chamber ignition device for an internal combustion engine, in particular for an internal combustion engine of a motor vehicle, and an internal combustion engine, in particular for a motor vehicle, in which unfavorable combustion can be avoided.

[0004] According to the invention, this object is achieved by a pre-chamber ignition device having the features of claim 1 and by an internal combustion engine having the features of claim 15. Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0005] A first aspect of the present invention relates to a pre-chamber ignition device for an internal combustion engine, in particular an internal combustion engine of a motor vehicle, also referred to as a pre-chamber ignition system. This means that the internal combustion engine comprises the pre-chamber ignition device in its fully manufactured state. Furthermore, it is provided, for example, that the motor vehicle, also referred to as a vehicle and designed, for example, as an automobile, in particular a sedan, comprises the internal combustion engine and therefore the pre-chamber ignition device and can be driven by means of the internal combustion engine. Particularly preferably, the internal combustion engine is designed as a reciprocating piston internal combustion engine, and therefore as a reciprocating piston motor. The internal combustion engine is also referred to as an internal combustion motor or motor. The pre-chamber ignition device comprises a pre-chamber and a plurality of overflow openings, in particular designed as through-holes. The pre-chamber is connected or can be connected in a flow-conducting manner to the combustion chamber of the internal combustion engine, also referred to as the main combustion chamber, via these overflow openings. At least a portion of the fuel-air mixture (which is in particular initially received or can be received in the main combustion chamber and is also referred to simply as a mixture) can be introduced from the combustion chamber into the precombustion chamber via these overflow openings, wherein the mixture comprises, in particular, liquid fuel and air. The mixture may also include at least one other component, such as recycled exhaust gas. This means that the internal combustion engine, in its fully manufactured state, comprises the combustion chamber and a precombustion chamber ignition device assigned to the combustion chamber, the precombustion chamber of which is connected to the combustion chamber in a fluid-conducting manner via the overflow openings and, for example, is otherwise fluidically separated from the combustion chamber. In other words, it is preferably provided that each overflow opening constitutes or is the only fluid-conducting connection between the main combustion chamber and the precombustion chamber. On the one hand, these overflow openings, in particular at one end, open into the precombustion chamber. On the other hand, in particular at the other end, these overflow openings open into the environment of the precombustion chamber device. In the fully assembled state of the internal combustion engine, the environment is the main combustion chamber, so that in the fully assembled state of the internal combustion engine, the overflow opening opens into the combustion chamber (main combustion chamber) on the other hand—particularly at the other end. Thus, in the fully assembled state of the internal combustion engine, the precombustion chamber is fluidically connected to the combustion chamber via the overflow opening and is preferably otherwise fluidically isolated from the combustion chamber. The precombustion chamber, and therefore the precombustion chamber ignition device, is particularly designed to carry out precombustion chamber ignition, particularly during combustion operation of the internal combustion engine and particularly preferably within a corresponding working cycle of the internal combustion engine. In particular, it is provided that, apart from the corresponding fluid-conducting connection between the precombustion chamber and the combustion chamber formed by the corresponding overflow opening, the precombustion chamber is completely fluidically isolated from the combustion chamber. In the fully assembled state of the internal combustion engine, the combustion chamber is, for example, partially bounded by a piston and, for example, partially by a cylinder in which the piston can be movably received, particularly translationally.For example, particularly within a corresponding working cycle of the internal combustion engine, the aforementioned mixture is formed in the combustion chamber and / or introduced into the combustion chamber, such that, particularly within a corresponding working cycle of the internal combustion engine, the mixture is initially received in the combustion chamber. At least the aforementioned portion of the mixture flows from the combustion chamber (main combustion chamber) through the transfer opening and thus into the precombustion chamber via the transfer opening, particularly when the piston moves toward or reaches its top dead center, such that, particularly within a corresponding working cycle, at least the aforementioned portion of the mixture is introduced from the main combustion chamber into the precombustion chamber via the transfer opening. The portion of the mixture that flows through the transfer opening and thus flows from the combustion chamber into the precombustion chamber via the transfer opening is also referred to as the first portion of the mixture. In particular, it is conceivable that, particularly during the piston's travel toward or at its top dead center, the piston conveys at least the first portion of the mixture from the main combustion chamber through the transfer opening and thus into the precombustion chamber, such that at least the first portion of the mixture is introduced into the precombustion chamber. In this case, it is in particular conceivable that a second portion of the mixture remains in the main combustion chamber and therefore in particular outside the pre-combustion chamber.

[0006] Furthermore, the pre-combustion chamber ignition device includes a spark plug, also referred to as an ignition element, by means of which at least one ignition spark can be generated in the pre-combustion chamber, and in particular within a corresponding operating cycle, for igniting the first portion introduced into the pre-combustion chamber via the overflow opening. Reference to the portion above or below is to be understood as meaning, unless otherwise stated, the first portion. Thus, particularly within a corresponding operating cycle, the mixture flowing into or introduced into the pre-combustion chamber, i.e., the first portion, is ignited, particularly by generating an ignition spark in the pre-combustion chamber by means of the spark plug. The spark plug includes an ignition electrode, particularly one ignition electrode, which is also referred to as or can be designed as an intermediate electrode. The at least one ignition spark or one ignition spark can be generated by means of the ignition electrode to ignite the portion of the mixture introduced into the pre-combustion chamber via the overflow opening between the ignition electrode and a corresponding ground electrode. It is preferably provided that the pre-combustion chamber ignition device includes the ground electrode as the sole ground electrode for generating the ignition spark. Therefore, it is preferably provided that the pre-combustion chamber ignition device has at least two electrodes, or preferably exactly two electrodes, namely an ignition electrode and a ground electrode, between which the at least one or exactly one ignition spark can be generated, in particular within a corresponding working cycle. With the aid of the ignition spark, the mixture flowing into the pre-combustion chamber and thus received therein, namely the first portion, is ignited and thus burns. The mixture ignited and then burned in the pre-combustion chamber then flows from the pre-combustion chamber through the overflow opening and back into the main combustion chamber via the overflow opening, for example in the form of a burning torch or jet flowing through the overflow opening. As the burning mixture flows from the pre-combustion chamber through the overflow opening and thus into the main combustion chamber via the overflow opening, the remaining mixture remaining in the combustion chamber, namely the aforementioned second portion, is ignited and then burns. Thus, for example, the piston is driven and thus moves toward or into its bottom dead center.

[0007] To prevent unfavorable, undesirable ignition and combustion of the mixture and thus ensure particularly favorable operation, in particular combustion, of the internal combustion engine, the present invention provides for the spark plug with the ignition electrode and the ground electrode to be constructed as structurally separate components. Preferably, the spark plug itself—that is, considered separately—has an ignition electrode but no corresponding ground electrode. The feature "the spark plug and the ground electrode are constructed as structurally separate components" should be understood as follows: when discussing these components above and below, this means that, unless otherwise stated, they are the spark plug and the ground electrode, so that, for example, the spark plug is the first component and the ground electrode is the second component. In the fully assembled state of the internal combustion engine with the pre-chamber ignition system, the first and second components, namely the spark plug and the ground electrode, are, for example, mounted on a third component of the internal combustion engine, in particular such that the first and second components are fixed to the third component. Here, for example, the first and second components are mounted or fixed to a third component in such a manner that relative movement between the first and third components, as well as relative movement between the second and third components, and between the first and second components, is prohibited. For example, the third component is a cylinder head of an internal combustion engine. For example, the cylinder head forms a combustion chamber dome associated with the combustion chamber, which partially defines the combustion chamber. Here, the piston is movable, for example, translationally, within the cylinder and relative to the combustion chamber. Because the spark plug and the ignition electrode are now designed as structurally separate components, the spark plug can be detached, or loosened, from the third component and moved away from the third component independently of the second component, i.e., while the second component remains mounted on the third component, in particular, the second component remains mounted on the third component in such a manner that relative movement between the third and second components is prohibited. Furthermore, for example, it is possible, in particular in a method for producing an internal combustion engine, to initially mount the second component independently of the first component, in particular to fix it, on the third component, in particular to prevent relative movement between the second and third components, while the first component is not (yet) mounted on the third component and is therefore still loose and spaced apart from the third component. The first component may, for example, only be mounted, in particular to fix it, on the third component after the second component has been completely mounted on the third component, in particular to prevent relative movement between the first and third components.In other words, the ground electrode is not a component of the spark plug, so that the ground electrode is not installed on the third component without or without the need for installing the spark plug on the third component, and / or the spark plug is not installed on the third component without or without the need for installing the ground electrode on the third component, and / or the spark plug is not removed from the third component without or without the need for removing the ground electrode from the third component. Thus, the spark plug can be removed from the third component without the ground electrode being removed from the third component, i.e., while the ground electrode remains installed on the third component. Due to this structural separation of the spark plug and the ground electrode, excessive heating of the ground electrode can be avoided, particularly during combustion operation of the internal combustion engine, thereby preventing undesirable, unintended ignition and / or combustion of the mixture. The present invention is based, in particular, on the recognition that, because the mixture flows from the combustion chamber through the overflow opening, particularly within a corresponding working cycle, and thus flows into the precombustion chamber via the overflow opening, particularly by being transported or conveyed into the precombustion chamber via the overflow opening by means of a piston, the precombustion chamber is a so-called passive precombustion chamber. In order to achieve particularly high power, especially specific power, for internal combustion engines, such as gasoline engines, a particularly large precombustion chamber volume is desirable, so that, for example, the precombustion chamber volume is at least 0.2% of the engine's displacement. Because the precombustion chamber of the precombustion chamber ignition device according to the present invention is a passive precombustion chamber, it is one that is flushed with the mixture, also known as combustion gas, only on the combustion chamber side. Such a passive precombustion chamber can lead to advantageously fast combustion in the main combustion chamber, especially in gasoline engines. This is achieved by igniting the mixture within the precombustion chamber, also known as pre-ignition, using a torch, also known as a torch jet, which flows at high speed through the overflow opening and thus flows from the precombustion chamber into the combustion chamber via the overflow opening, generating multiple combustion points in the combustion chamber. Compared to conventional solutions, combustion in the main combustion chamber can proceed more than twice as fast. This significantly reduces the pre-ignition requirement. Consequently, high power density can be achieved without using a substoichiometric combustion air ratio (enrichment). To keep the combustion duration advantageously short and, in particular, to such an extent that enrichment can be avoided, a large-volume pre-chamber, such as the pre-chamber of the pre-chamber ignition device according to the present invention, can be used in internal combustion engines with high power density, particularly those designed as gasoline engines. However, single-piece spark plugs, also known as pre-chamber spark plugs, or conventional spark plugs in combination with a separate pre-chamber, are prone to premature ignition or incandescent ignition, particularly at high pre-chamber volumes, due to the high temperatures of the components of the pre-chamber spark plug or conventional spark plug. It has been found that, in particular, the ground electrode of conventional spark plugs or pre-chamber spark plugs, in combination with high pre-chamber volumes, tends to overheat. Furthermore, the pre-chamber volume of single-piece pre-chamber spark plugs is not only thermally limited but also limited by the combustion chamber in the cylinder head.In conventional spark plugs and conventional pre-chamber spark plugs, the ground electrode is a fixed component of the spark plug or pre-chamber spark plug, so that the conventional pre-chamber spark plug or spark plug is an inseparable structural unit with the ignition electrode and the ground electrode, which are designed as center electrodes, for example.

[0008] Because the spark plug and ground electrode are structurally separated according to the present invention, excessive heating of the ground electrode can be avoided. Undesirable pre-ignition and hot ignition can thus be prevented, ensuring effective and efficient operation of the internal combustion engine. In particular, the structural separation of the spark plug and ground electrode, or vice versa, allows the ground electrode to be constructed particularly robustly and thus have a particularly high mass, resulting in a higher thermal capacity than conventional solutions. This reduces the maximum temperature of the ground electrode during the combustion cycle compared to conventional solutions. Furthermore, a particularly advantageous, large-area connection of the ground electrode to a third component, particularly the cylinder head, can be achieved, for example, resulting in improved heat conduction compared to conventional solutions. This means that heat can be better transferred or dissipated from the ground electrode to the third component than with conventional solutions, preventing excessive ground electrode temperatures.

[0009] In order to be able to avoid unwanted ignition and combustion and thus to ensure particularly advantageous operation of the internal combustion engine, it is provided in one embodiment of the present invention that the pre-combustion chamber ignition device has a housing element which is constructed separately from the spark plug and separately from the ground electrode and preferably also separately from the third component, and in which the spark plug is at least partially, in particular at least mainly and therefore at least more than half, accommodated, i.e. arranged.

[0010] It has proven particularly advantageous to support the ground electrode directly on the housing element and, therefore, in particular, to bear directly against the housing, thereby enabling particularly advantageous heat dissipation from the ground electrode. In addition to the direct support of the ground electrode on the housing element, a direct connection between the ground electrode and the housing element is prohibited, such that the ground electrode is not directly connected to the housing element. This allows, for example, a particularly advantageous, in particular structural, separation of the spark plug from the ground electrode, or vice versa, so that excessively high ground electrode temperatures can be avoided.

[0011] In order to advantageously design the spark plug and the ground electrode as structurally separate components and, on the other hand, to enable simple and therefore time- and cost-effective manufacture of the internal combustion engine, another embodiment of the present invention provides that the ground electrode is directly connected to the housing element. In the fully manufactured state of the internal combustion engine, for example, the housing element is mounted, in particular directly, on a third component, in particular such that relative movement between the housing element and the third component is prohibited. For example, the housing element is directly connected to the third component, in particular such that the housing element is directly screwed to the third component. For example, since the ground electrode is directly connected to the housing element, for example, mounting the housing element on the third component is accompanied by mounting the ground electrode on the third component, or vice versa, the internal combustion engine can be manufactured in a time- and cost-effective manner. Furthermore, this makes it particularly advantageous to transfer heat from the ground electrode to the housing element, for example, from the housing element to the third component, thereby preventing excessive temperatures in the ground electrode.

[0012] It has proven particularly advantageous to weld the ground electrode directly to the housing element and thus connect it, in particular by friction welding. This allows for a particularly advantageous transfer of heat from the ground electrode to the housing element and thus dissipation of heat from the ground electrode, thereby preventing excessively high temperatures of the ground electrode and thus undesirable, disadvantageous combustion and ignition of the mixture.

[0013] In another particularly advantageous embodiment of the present invention, the spark plug is screwed directly to the housing element and is thus directly connected to the housing element. Preferably, the spark plug is screwed to the housing element and is thus connected in a non-destructively detachable manner. This allows for simple and advantageous manufacture of the internal combustion engine while ensuring an advantageous structural separation between the spark plug and the ground electrode.

[0014] For example, the spark plug, in particular the housing of the spark plug, has a first thread, in particular in the form of a first external thread. For example, the housing element has a second thread corresponding to the first thread, in particular in the form of a first internal thread. It is preferably provided that the first and second threads are directly screwed together, in particular such that the first external thread is screwed directly into the first internal thread.

[0015] Another embodiment is characterized in that the pre-chamber ignition device includes a cylinder head for an internal combustion engine that is designed separately from the spark plug, the ground electrode, and the housing element. The housing element, the spark plug, and the ground electrode are each at least partially disposed within the cylinder head. For example, the ground electrode and / or the housing element may be completely disposed within the cylinder head. Heat can thus be transferred particularly advantageously from the ground electrode directly to the cylinder head and / or via the housing element, thereby preventing excessive temperatures and, therefore, unfavorable combustion and ignition of the mixture.

[0016] It has proven particularly advantageous to screw the housing element directly to the cylinder head and thus to be directly connected thereto. In particular, the housing element is screwed to the cylinder head in a non-destructive, detachable manner. This allows, on the one hand, for the internal combustion engine to be manufactured particularly time- and cost-effectively. On the other hand, heat can be particularly advantageously transferred from the housing element to the cylinder head and thus away from the ground electrode, thereby advantageously preventing excessively high ground electrode temperatures.

[0017] For example, the housing element may have a third thread, which may be in the form of a second external thread, and the cylinder head may have a fourth thread corresponding to the third thread, which may be in the form of a second internal thread. For example, the third and fourth threads may be directly screwed together, so that the housing element is directly screwed to the cylinder head. Here, for example, the second external thread is screwed directly into the second internal thread.

[0018] Preferably, provision is made for preventing direct connections between the ground electrode and the cylinder head, in particular with the exception of at least one or precisely one direct contact between the ground electrode and the cylinder head and / or with the exception of at least one or precisely one electrically conductive connection between the ground electrode and the cylinder head. This ensures a particularly advantageous structural separation between the spark plug and the ground electrode, thereby preventing excessively high temperatures of the ground electrode.

[0019] It has proven particularly advantageous for the ground electrode to be directly screwed to the cylinder head. This allows for particularly advantageous heat transfer from the ground electrode directly to the cylinder head, thereby reliably preventing excessive ground electrode temperatures. For example, a third thread, particularly designed as an external thread, extends, particularly continuously, on the housing element and the ground electrode, particularly on a first circumferential surface of the housing element and a second circumferential surface of the ground electrode. This allows both the housing element and the ground electrode to be screwed directly to the fourth thread and, therefore, directly to the cylinder head, via the third thread. This allows for a particularly advantageous mechanical and, particularly, thermal connection of both the housing element and the ground electrode to the cylinder head, enabling particularly advantageous heat transfer from the ground electrode to the cylinder head, directly to the housing element, and via the housing element to the cylinder head. This advantageously prevents excessive ground electrode temperatures.

[0020] To achieve particularly favorable combustion, another embodiment of the present invention provides that a first portion of the precombustion chamber is defined, in particular directly, by a first housing component that is designed separately from the spark plug, the ground electrode, the housing element, and preferably also separately from the third component. For example, a first subregion of the first housing component is disposed in the third component, while a second subregion of the first housing component projects into the main combustion chamber. For example, the overflow openings, in particular all overflow openings, are designed in the first housing component, in particular each completely therein, so that, for example, the respective overflow openings are designed as corresponding through-holes that extend, in particular completely through the first housing component, also referred to as through-holes. The second portion of the precombustion chamber is defined, in particular directly, by a second housing component that is designed separately from the spark plug, the ground electrode, the housing element, the first housing component, and preferably also separately from the third component. The second portion is preferably larger than the first portion. This ensures a particularly large volume of the precombustion chamber in a particularly advantageous manner, and advantageously prevents undesired combustion and ignition.

[0021] It has proven particularly advantageous to design the housing parts separately from the cylinder head. This allows particularly advantageous thermal conditions to be achieved, so that overheating points and thus disadvantageous, undesirable combustion and ignition can be avoided.

[0022] For example, the second housing part is arranged, in particular completely arranged, in the cylinder head; for example, the second housing part can be arranged, in particular completely arranged, outside the combustion chamber.

[0023] In another particularly advantageous embodiment of the present invention, the first housing component is made of a first material, and the second housing component is made of a second material different from the first material. Preferably, the first material is a metal. Alternatively or additionally, the second material can be a metal. This achieves particularly favorable thermal conditions, preventing overheating and, therefore, unintended ignition and combustion.

[0024] The first material is preferably a nickel-based alloy, particularly preferably Inconel®. The second material is preferably copper or a copper alloy. In particular, for example, the second material is a copper-zirconium alloy. This allows for particularly favorable thermal conditions.

[0025] Finally, it has proven particularly advantageous if at least one third portion of the precombustion chamber, designed as a residual gas chamber, is delimited, in particular directly, by the housing element. Preferably, the third portion is smaller than the second portion and smaller than the first portion. To thereby achieve particularly favorable thermal conditions and, in particular, to avoid excessively high temperatures of the ground electrode, a further embodiment of the invention provides that at least one fourth portion of the precombustion chamber is arranged in a through-hole in the ground electrode and is thus delimited, in particular directly, by the ground electrode, the through-hole of the ground electrode opening directly into the second portion at one end and directly into the third portion at the other end. Preferably, the fourth portion is smaller than the third portion, smaller than the second portion, and preferably smaller than the first portion.

[0026] In order to be able to particularly advantageously avoid excessively high temperatures of the ground electrode, a further embodiment of the invention provides that the ground electrode is designed in a disk-shaped manner, ie, as a disk body. Here, the ground electrode is designed, for example, in a cylindrical manner on the outer circumference side.

[0027] Another embodiment is characterized in that the ground electrode has an engagement opening designed as a through-hole, which is provided, in particular, in addition to the through-hole in which the fourth part is provided, and into which an ignition electrode, for example, designed as a center electrode, engages. Thus, for example, the ground electrode can be particularly advantageously provided with a high mass, so that excessively high temperatures of the ground electrode can be advantageously avoided.

[0028] Finally, it has proven particularly advantageous if the ground electrode is sealed relative to the second housing part by means of at least one sealing device. For example, the sealing device is or includes at least one or precisely one sealing element, which is particularly designed separately from the ground electrode and the second housing part, and preferably also separately from the first housing part and the housing element, by means of which the ground electrode is sealed relative to the second housing part. For example, the sealing device, in particular the sealing element, rests on the ground electrode on one side and on the second housing part on the other side, in particular directly in each case. The sealing device, in particular the sealing element, can be designed as a solid body; for example, the sealing device, in particular the sealing element, can be made of a metallic material such as copper. It is also conceivable that the sealing device, in particular the sealing element, can be designed as a liquid seal. The sealing element can be used to achieve advantageous sealing of the precombustion chamber, allowing for particularly advantageous and efficient operation.

[0029] A second aspect of the present invention relates to an internal combustion engine, also referred to as an internal combustion motor or motor, and preferably designed as a reciprocating piston motor, i.e., a reciprocating piston internal combustion engine, which has at least one pre-chamber ignition device according to the first aspect of the present invention. The advantages and advantageous aspects of the first aspect of the present invention can be considered as advantages and advantageous aspects of the second aspect of the present invention, and vice versa. The internal combustion engine preferably has at least one or more combustion chambers, each of which is equipped with a pre-chamber ignition device according to the first aspect of the present invention, in particular, precisely one pre-chamber ignition device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further details of the present invention are obtained from the subsequent description of the preferred embodiments in conjunction with the accompanying drawings. The drawings are as follows:

[0031] Figure 1 A schematic sectional view partially shows an internal combustion engine for a motor vehicle, the internal combustion engine having a pre-chamber ignition device;

[0032] Figure 2 a schematic and cross-sectional exploded view partially showing a pre-chamber ignition device; and

[0033] Figure 3 A further schematic sectional view shows a detail of an internal combustion engine.

[0034] In the figures, identical or functionally identical elements are provided with the same reference symbols. DETAILED DESCRIPTION

[0035] Figure 1A schematic partial cross-sectional view shows an internal combustion engine 1 for a motor vehicle, also referred to simply as a vehicle. The internal combustion engine is also referred to as a motor or internal combustion engine and is designed as a reciprocating piston motor, thus a reciprocating piston internal combustion engine. This means that the motor vehicle, in its fully assembled state, comprises and can be driven by the internal combustion engine 1. The internal combustion engine 1 has at least one combustion chamber 2, which is defined in part by a cylinder 3, in part by a piston 4, and in part by a combustion chamber head 5. The cylinder 3 is formed by the cylinder housing of the internal combustion engine 1, which is designed, for example, as a cylinder crankcase. The piston 4 is arranged in a translationally movable manner in the cylinder 3 and is therefore translationally movable relative to the cylinder housing between top dead center and bottom dead center. The combustion chamber head 5 is formed by the cylinder head 6 of the internal combustion engine 1, which is separate from and connected to the cylinder housing.

[0036] The internal combustion engine 1 has a pre-chamber ignition device 7 , which can include, for example, a cylinder head 6 . Figure 2 The pre-chamber ignition device 7, also referred to as a pre-chamber system or pre-chamber device for short, is shown partially in a schematic sectional and perspective exploded view. Figure 3 The visible precombustion chamber 8 and a plurality of overflow openings 9 designed as through-holes, via which the precombustion chamber 8 is fluidically connected to the combustion chamber 2, also referred to as the main combustion chamber, of the internal combustion engine 1. The precombustion chamber 8 is fluidically connected to the combustion chamber 2 via the overflow openings 9 and is otherwise completely fluidically separated from the combustion chamber 2. A fuel-air mixture, also referred to simply as a mixture and comprising preferably liquid fuel and air, can be introduced from the combustion chamber 2 into the precombustion chamber 8 via these overflow openings 9.

[0037] Particularly well by Figure 1 and Figure 3 As can be seen from the preceding figures, the pre-chamber ignition device 7 includes a spark plug 10 having an ignition electrode 11, for example, configured as a center electrode. Using the ignition electrode 11, at least one ignition spark can be generated in the pre-chamber 8 between the ignition electrode 11 and a corresponding ground electrode 12, particularly within a corresponding operating cycle of the internal combustion engine 1. In particular, within a corresponding operating cycle of the internal combustion engine 1, a first portion of the mixture flows from the main combustion chamber into the pre-chamber 8 via the overflow opening 9, while a second portion of the mixture, for example, remains in the main combustion chamber (combustion chamber 2). Using the ignition spark, within a corresponding operating cycle, the portion of the mixture that has flowed into the pre-chamber 8 can be ignited and thus burned. The ignited and thus burning or combusting mixture flows through the overflow opening 9 and thus exits the pre-chamber 8 via the overflow opening 9 and flows into the main combustion chamber (combustion chamber 2), where the burning first portion of the mixture ignites the second portion of the mixture, thereby combusting. This, for example, drives the piston 4.

[0038] In order to avoid excessively high temperatures of ground electrode 12 and thus undesirable, adverse ignition and combustion of the mixture, spark plug 10 with ignition electrode 11 and ground electrode 12 are designed as structurally separate components. In this case, spark plug 10 itself—that is, considered separately—does not have its own ground electrode corresponding to ignition electrode 11.

[0039] Pre-chamber ignition device 7 includes a housing element 13 that is designed separately from spark plug 10, separate from ground electrode 12, and separate from cylinder head 6. As will be explained in more detail below, this housing element is designed as or serves as an adapter sleeve. In the exemplary embodiment shown in the figures, ground electrode 12 is designed as a disk that is cylindrical on its outer circumference and therefore circular. As will be explained in more detail below, ground electrode 12 has a plurality of, and therefore at least two, or exactly two, through-holes 14 that extend completely through ground electrode 12. Furthermore, ground electrode 12 has an engagement opening 15, provided in addition to through-holes 14 and designed as a further through-hole, that extends completely through ground electrode 12. Ignition electrode 11 engages in engagement opening 15, particularly the central engagement opening 15, of ground electrode 12. In the exemplary embodiment shown in the figures, housing element 13 is at least partially disposed in cylinder head 6, and ground electrode 12 is disposed completely in cylinder head 6. Spark plug 10 is at least partially disposed in cylinder head 6 and at least partially in housing element 13. In the exemplary embodiment shown in the figures, ground electrode 12 is directly connected to housing element 13, for example, such that ground electrode 12 is directly welded to housing element 13 by friction welding and thus connected. Alternatively, it is also conceivable that ground electrode 12 is directly supported on housing element 13, with no provision being made, i.e., prohibited, for a direct connection between ground electrode 12 and housing element 13, apart from this direct support of ground electrode 12 on housing element 13.

[0040] In the exemplary embodiment shown in the figures, spark plug 10 is screwed directly to housing element 13. To this end, spark plug 10 has a first thread 21 in the form of a first external thread, and housing element 13 has a second thread 22 in the form of a first internal thread corresponding to first thread 21. The first external thread is screwed directly into the first internal thread. In the exemplary embodiment shown in the figures, housing element 13 and ground electrode 12 form a third thread 16 in the form of a second external thread, so that third thread 16 extends, in particular, continuously over at least a portion of housing element 13 and at least a portion of ground electrode 12, and is thus formed in at least a partial region of housing element 13 and at least a partial region of ground electrode 12. In other words, housing element 13 has a first thread portion of thread 16, and ground electrode 12 has a second thread portion of thread 16, and in particular, the thread portions directly intersect and preferably are aligned. Cylinder head 6, which is designed separately from housing element 13 and ground electrode 12, has a fourth thread 17 in the form of a second internal thread corresponding to third thread 16. Third thread 16 and fourth thread 17 are directly screwed together, in particular, such that the second external thread is screwed directly into the second internal thread. Thus, both housing element 13 and ground electrode 12 are directly screwed to cylinder head 6, in particular, are directly screwed into cylinder head 6. Furthermore, as can be seen from the figures, spark plug 10, for example, can be detached from housing element 13 and cylinder head 6 and thus removed, in particular, can be unscrewed, while housing element 13 and ground electrode 12 remain screwed to cylinder head 6 and thus remain mounted on, and thus secured to, cylinder head 6. This structural separation between spark plug 10, on the one hand, and ground electrode 12, on the other, prevents excessive temperatures in ground electrode 12.

[0041] In the embodiment shown in the drawings, a first portion T1 of the precombustion chamber 8 is defined, in particular directly, by a first housing component 18. In particular, a second portion T2 of the precombustion chamber 8 is larger than the first portion T1 and is defined, in particular directly, by a second housing component 19. Preferably, housing components 18 and 19 are constructed separately and connected to each other, in particular directly. For example, housing components 18 and 19 are directly welded to each other, in particular by friction welding, and thus directly connected. Particularly preferably, housing component 18 is constructed from a first material, in particular a metallic material, and housing component 19 is constructed from a second material, in particular a metallic material, different from the first material. For example, the first material is a nickel-based alloy, such as Inconel®, and the second material is a copper alloy, in particular a copper-zirconium alloy. Housing element 13 is constructed from a third material, in particular a material different from the first material. For example, the third material corresponds to the second material or is a material different from the second material. Cylinder head 6 is constructed from a fourth material, in particular, a metallic material. The third material is preferably a metallic material. The fourth material is preferably a material different from the third material and / or the second material and / or the first material. Particularly preferably, the fourth material is aluminum or an aluminum alloy. Preferably, the third material has a first coefficient of thermal expansion, for example, and the fourth material has a second coefficient of thermal expansion. Preferably, the difference between the first and second coefficients of thermal expansion is at most 6, particularly at most 5, and particularly preferably at most 4. For example, the coefficient of thermal expansion of the fourth material is 17, for example, while the coefficient of thermal expansion of the third material is 17. This prevents excessive thermally induced relative movements and resulting stresses between the housing element 13 and the cylinder head 6.

[0042] Since the housing parts 18 and 19 are connected to one another, in particular directly to one another, the housing parts 18 and 19 form a housing lower part, which is also referred to as the lower part for short. The housing lower part is preferably connected to the cylinder head 6, in particular directly, when considered in isolation, i.e. when considering the housing lower part and the cylinder head 6 separately, in particular connected in such a way that the housing part is pressed onto the cylinder head 6, in particular pressed into the cylinder head 6. Figure 3 It can be seen that housing part 19 is completely arranged in cylinder head 6. A first part of housing part 18 is arranged in cylinder head 6, and a second part of housing part 18 is arranged outside cylinder head 6 and protrudes into the main combustion chamber. In this case, overflow openings 9, in particular all overflow openings, are arranged in the second part of housing part 18. It can be seen in particular that overflow openings 9, in particular all overflow openings, are formed in housing part 18.

[0043] Pre-chamber ignition device 7 also includes a sealing device, referred to as sealing element 20, which is designed separately from housing parts 18 and 19, separate from ground electrode 12, separate from cylinder head 6, separate from housing element 13, and also separate from spark plug 10. Sealing element 20 is currently arranged between ground electrode 12 and the lower housing part, in particular housing part 19, and is particularly arranged such that sealing element 20 supports, in particular directly supports, and therefore bears against, ground electrode 12 on the one hand, and supports, in particular directly supports, and therefore bears against, housing part 19 on the other hand. In the current embodiment, sealing element 20 is designed as a sealing ring. Ground electrode 12 is sealed relative to second housing part 19 by means of sealing element 20.

[0044] The press-fit connection between the housing lower part and cylinder head 6 creates particularly favorable heat transfer between the two parts, preventing excessive temperatures. In particular, it is conceivable for housing part 19 and / or housing part 18 to be press-fitted, in particular directly press-fitted, to cylinder head 6. For example, sealing element 20 may be formed from a metallic material, such as copper. For example, except for the provision that sealing element 20, for example, configured as a sealing ring, bears, in particular directly, on ground electrode 12 and on housing part 19, direct connections between sealing element 20 and ground electrode 12 and between sealing element 20 and housing part 19 are not provided, i.e., are not formed. Therefore, except for the provision that sealing element 20 bears, in particular directly, on ground electrode 12 and on housing part 19, sealing element 20 is not connected to ground electrode 12 or to housing part 19.

[0045] Particularly well by Figure 1 and Figure 3 As can be seen, at least two, or precisely two, third sections T3 of the precombustion chamber 8, which are formed as residual gas chambers, are bounded, in particular directly, by the housing element 13. For example, the respective volumes of the residual gas chambers may total at least 30% of the total volume of the precombustion chamber 8. For each third section T3, a corresponding fourth section T4 of the precombustion chamber 8 is disposed in a corresponding through-hole 14 of the ground electrode 12, so that the number of residual gas chambers corresponds to the number of fourth sections T4 or through-holes 14. Thus, the respective fourth section T4 is formed, in particular directly, by the ground electrode 12. The through-hole 14 of the ground electrode 12 opens directly into the third section T3 on the one hand and into the second section T2 on the other hand. This allows for a particularly large volume of the precombustion chamber 8 to be achieved in a space-saving manner, for example, a volume of precisely or at least 1000 cubic millimeters.

[0046] Because the third material and the fourth material have the same or similar coefficients of thermal expansion, heat can be transferred particularly well from housing element 13 to cylinder head 6. Furthermore, heat can be transferred particularly well from ground electrode 12 to housing element 13 and directly to cylinder head 6, enabling advantageous heat removal away from ground electrode 12. Excessive temperatures of ground electrode 12 can thus be avoided. It can also be seen that spark plug 10 is mounted or held on cylinder head 6 by means of housing element 13, so that housing element 13 is designed or serves as an adapter sleeve or adapter bushing.

[0047] The respective residual gas chamber is or comprises a respective residual gas volume in which residual gas can be accommodated. In this case, the residual gas volume can be designed to be particularly large.

[0048] By means of the ignition electrode 11, an ignition spark can be generated between the ignition electrode 11 and the ground electrode 12 at the ignition point, also referred to as the ignition location. The corresponding residual gas chamber, i.e., the corresponding residual gas volume, is arranged on the side of the ignition point facing away from the main combustion chamber and is therefore arranged above the ignition point. This arrangement of the corresponding residual gas volume above the ignition point contributes to a particularly favorable mixture formation at the ignition point, since the residual gas that is always present is concentrated there.

[0049] For example, by Figure 2 It can be seen that the number of residual gas spaces and therefore the number of through-holes 14 is 4, so that, for example, the ground electrode 12 has exactly 5 through-holes overall, namely through-holes 14 and one engagement opening 15. However, this is merely an example, although advantageous.

[0050] Reference Signs List

[0051] 1 Internal combustion engine

[0052] 2 combustion chambers

[0053] 3 cylinders

[0054] 4 pistons

[0055] 5 Combustion chamber top

[0056] 6 cylinder heads

[0057] 7 Pre-combustion chamber ignition device

[0058] 8 Precombustion chamber

[0059] 9 Overflow opening

[0060] 10 spark plugs

[0061] 11 ignition electrodes

[0062] 12 grounding electrodes

[0063] 13 housing elements

[0064] 14 through holes

[0065] 15 scarf opening

[0066] 16Third thread

[0067] 17 Fourth thread

[0068] 18 first housing component

[0069] 19 second housing component

[0070] 20 sealing elements

[0071] 21 First thread

[0072] 22 second thread

[0073] T1 Part 1

[0074] T2 Part 2

[0075] T3 Part 3

[0076] T4 Part 4

Claims

1. A pre-combustion chamber ignition device (7) for an internal combustion engine (1), comprising: a pre-combustion chamber (8); a plurality of overflow openings (9), via which the pre-combustion chamber (8) is fluidically connected to a combustion chamber (2) of the internal combustion engine (1) and at least a portion of a mixture of fuel and air can be introduced from the combustion chamber (2) into the pre-combustion chamber (8); and a spark plug (10), wherein the spark plug has an ignition electrode (11), by means of which at least one ignition spark can be generated in the pre-combustion chamber (8) between the ignition electrode (11) and a corresponding ground electrode (12) for igniting the portion introduced into the pre-combustion chamber (8) via the overflow openings (9), characterized in that A spark plug (10) having an ignition electrode (11) and a ground electrode (12) are formed as structurally separate components.

2. The pre-combustion chamber ignition device (7) according to claim 1, characterized in that A housing element (13) is configured separately from the spark plug (10) and separately from the ground electrode (12), and the spark plug (10) is at least partially accommodated in the housing element.

3. The pre-combustion chamber ignition device (7) according to claim 2, characterized in that: The ground electrode (12) is directly supported on the housing element (13), and a direct connection between the ground electrode (12) and the housing element (13) is prohibited except that the ground electrode (12) is directly supported on the housing element (13).

4. The pre-combustion chamber ignition device (7) according to claim 2, characterized in that The ground electrode (12) is directly connected to the housing element (13).

5. The pre-combustion chamber ignition device (7) according to claim 4, characterized in that: The ground electrode (12) is welded directly to the housing element (13) and is thus connected.

6. The pre-combustion chamber ignition device (7) according to any one of claims 2 to 5, characterized in that: The spark plug (11) is directly screwed to the housing element (13).

7. The pre-combustion chamber ignition device (7) according to any one of claims 2 to 6, characterized in that A cylinder head (6) for an internal combustion engine (1) is designed separately from a spark plug (11), separately from a ground electrode (12), and separately from a housing element (13), wherein the housing element (13), the spark plug (11), and the ground electrode (12) are each at least partially arranged in the cylinder head (6).

8. The pre-combustion chamber ignition device (7) according to claim 7, characterized in that: The housing element (13) is directly screwed to the cylinder head (6).

9. The pre-combustion chamber ignition device (7) according to claim 7 or 8, characterized in that: The ground electrode (12) is directly threadedly connected to the cylinder head (6).

10. The pre-combustion chamber ignition device (7) according to any one of claims 2 to 9, characterized in that A first portion (T1) of the pre-combustion chamber (8) is defined by a first housing part (18), which is configured separately from the spark plug (11), separately from the ground electrode (12), and separately from the housing element (13); and A second portion (T2) of the pre-combustion chamber (8) is defined by a second housing part (19), which is designed separately from the spark plug (11), separately from the ground electrode (12), separately from the housing element (13), and separately from the first housing part (18).

11. The pre-chamber ignition device (7) according to claim 10 as dependent on any one of claims 7 to 9, characterized in that The housing parts (18, 19) are designed separately from the cylinder head (6).

12. The pre-combustion chamber ignition device (7) according to claim 10 or 11, characterized in that: The first housing component (18) is made of a first material, and the second housing component (19) is made of a second material different from the first material.

13. The pre-combustion chamber ignition device (7) according to any one of claims 10 to 12, characterized in that At least one third portion (T3) of the pre-combustion chamber (8), which is configured as a residual gas chamber, is defined by the housing element (13); and At least one fourth portion (T4) of the pre-combustion chamber (8) is arranged in a through-hole (14) of the ground electrode (12) and is therefore defined by the ground electrode (12), the through-hole (14) of the ground electrode opening directly into the second portion (T2) at one end and directly into the third portion (T3) at the other end.

14. The pre-combustion chamber ignition device (7) according to any one of claims 10 to 13, characterized in that: The ground electrode (20) is sealed relative to the second housing part (19) by means of at least one sealing device (20).

15. An internal combustion engine (1) having at least one pre-chamber ignition device (7) according to any one of the preceding claims.

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