DE102022101693B3 - Internal combustion engine with scavenging gas injection - Google Patents

Abstract

The invention relates to an internal combustion engine (1) with a combustion chamber (3) and a spark plug (8) for igniting a fuel/fresh gas mixture in the combustion chamber (3), with an ignition electrode (9) of the spark plug (8) in a fluidically is arranged connected to the combustion chamber (3) pre-chamber (10). It is provided that a scavenging gas introduction opening (18), through which scavenging gas supplied via a scavenging gas line (17) can be introduced into the antechamber (10), on the combustion chamber (3) in the axial direction with respect to a longitudinal center axis (13) of the spark plug (8). side facing away from the ignition electrode (9) opens into the antechamber (10).

Description

The invention relates to an internal combustion engine with a combustion chamber and a spark plug for igniting a mixture of fuel and fresh gas in the combustion chamber, with an ignition electrode of the spark plug being arranged in a prechamber fluidically connected to the combustion chamber, with a scavenging gas introduction opening through which scavenging gas is supplied via a scavenging gas line Flushing gas can be introduced into the antechamber, opens out into the antechamber on the side of the ignition electrode facing away from the combustion chamber in the axial direction with respect to a longitudinal center axis of the spark plug.

From the prior art, for example, the publication DE 100 16 558 A1 known. This describes a method for igniting very lean fuel-air mixtures with a spark-ignited prechamber spark plug arranged on the edge of the main combustion chamber of an internal combustion engine, which is connected to the main combustion chamber via overflow channels, with a small amount of additional fuel being introduced into the prechamber under valve control. Also shown is an arrangement, in particular for use in gas engines, with a prechamber surrounding a spark plug, which has preferably tangential overflow channels leading to the main combustion chamber, and with an extremely thin supply channel supplying additional fuel, via which, in particular with a solenoid valve, time-controlled under high pressure Pressurized fuel is metered during the compression stroke of the internal combustion engine.

The pamphlet DE 10 2019 209 753 A1 describes a spark plug which comprises an outer wall, a longitudinal axis, in the longitudinal direction an end on the combustion chamber side and an end facing away from the combustion chamber, the outer wall comprising a region on the combustion chamber side which is designed to be arranged in a combustion chamber, with a prechamber being arranged on the end on the combustion chamber side in which at least one ignition electrode is arranged and which has at least one opening on the combustion chamber side for passing on a mixture that has already been ignited in the antechamber into a combustion chamber. The outer wall is at least partially surrounded by a holder in the circumferential direction, with at least one flow channel for flushing the prechamber running through the holder and the outer wall in the area of the prechamber, which flow channel connects the prechamber to the area on the combustion chamber side, the flow channel for flushing the prechamber thereto is designed to be opened and closed in a cylinder head-installed state by displacement of the bracket relative to the cylinder head.

The publications are also from the prior art DE 10 2018 114 035 A1 and DE 10 2015 221 286 A1 known.

The object of the invention is to propose an internal combustion engine which has advantages over known internal combustion engines, in particular enabling particularly reliable ignition of the fuel/fresh gas mixture using the spark plug, preferably with a small space requirement or compact design.

According to the invention, this is achieved with an internal combustion engine having the features of claim 1 . It is provided that the spark plug and the antechamber are arranged at least in regions in a spark plug shaft of the internal combustion engine that has an internal thread, with the scavenging gas introduction opening being arranged in the axial direction so that they overlap the internal thread and/or the scavenging gas line is arranged so that the internal thread overlaps the scavenging gas introduction opening in terms of flow connected.

Advantageous configurations with expedient developments of the invention are specified in the dependent claims.

The internal combustion engine is used, for example, to drive a motor vehicle and to that extent to provide a drive torque aimed at driving the motor vehicle. The internal combustion engine can be part of the motor vehicle, but of course it can also be separate from it. In order to provide the drive torque, the internal combustion engine has one cylinder, but preferably has a plurality of cylinders. As far as the cylinder or the cylinders is mentioned in the context of this description, the explanations can always be transferred to each of the several cylinders or the cylinder of the internal combustion engine.

The cylinder is preferably configured in a cylinder crankcase of the internal combustion engine. A piston is arranged in the cylinder and is drivingly coupled to a crankshaft of the internal combustion engine, in particular via at least one connecting rod. The piston delimits the combustion chamber together with a cylinder wall of the cylinder and a cylinder roof of the cylinder. The cylinder wall is formed in particular by the cylinder crankcase. The cylinder roof is preferably on a cylinder head of the internal combustion engine, which is on the cylinder circuit housing is attached. In this respect, the cylinder head closes off the cylinder on the side opposite the piston. If there are several cylinders, each of these cylinders has a separate combustion chamber.

At least one intake port opens into the combustion chamber or into each combustion chamber. In addition, at least one outlet port extends from the combustion chamber or from each combustion chamber. During operation of the internal combustion engine, fresh gas or the fuel/fresh gas mixture is supplied to the combustion chamber via the at least one inlet channel. The fresh gas is to be understood in particular as fresh air, preferably from an external environment of the internal combustion engine. In addition to the fresh air, however, the fresh gas can contain exhaust gas in any proportion, provided that the internal combustion engine is designed for exhaust gas recirculation. If this is the case, exhaust gas discharged from the combustion chamber at least temporarily is fed back into the combustion chamber, namely via the at least one inlet port.

During operation of the internal combustion engine, fuel is preferably introduced into the combustion chamber by means of a fuel injector. For this purpose, the fuel injector opens, for example, into the combustion chamber or at least borders on it, namely in such a way that an injection nozzle of the fuel injector is fluidically connected to the combustion chamber or borders on it. The introduction of the fuel into the combustion chamber forms the fuel/fresh gas mixture in the combustion chamber. This is ignited by the spark plug and then burns. This produces exhaust gas, which is discharged from the combustion chamber, namely through the at least one outlet port. For this purpose, the at least one outlet channel starts from the combustion chamber.

To ignite the fuel/fresh gas mixture, the spark plug has the ignition electrode, by means of which an ignition spark can be generated at an ignition point of the spark plug. In particular, the ignition electrode interacts with at least one other ignition electrode for this purpose. The ignition electrode is in particular a center electrode through which a longitudinal center axis of the spark plug runs. The at least one further ignition electrode is preferably arranged off the longitudinal center axis, for example offset in the radial direction with respect to the ignition electrode.

The ignition electrode and in particular the ignition point are arranged in the antechamber, which is fluidically connected to the combustion chamber. To this extent, the ignition electrode or the ignition point is outside of the combustion chamber. The antechamber is to be understood as meaning a chamber which is separated from the combustion chamber by an antechamber wall, but is in fluid communication with it. For example, at least one overflow opening is designed for this purpose in the antechamber wall. There are particularly preferably several such overflow openings.

Like the combustion chamber, the antechamber is arranged in the cylinder, for example, in particular on the side of the cylinder roof facing the combustion chamber, preferably only partially or completely. However, it can also be provided that the antechamber is arranged at least partially or completely on the side of the cylinder facing away from the cylinder and in this respect outside of the cylinder. For this purpose, the antechamber is arranged, for example, in the cylinder head. The spark plug and the prechamber are preferably arranged in a spark plug well. Provision can be made for them to be completely present in the latter, or for at least the prechamber or the prechamber wall delimiting it to partially protrude from the spark plug shaft, that is to say protrude beyond the latter in the direction of the cylinder.

Fluid is at least intermittently exchanged between the combustion chamber and the antechamber via the overflow opening or the overflow openings. The fluid either flows from the combustion chamber into the antechamber or, conversely, from the antechamber into the combustion chamber. For example, provision is made for the unburned fuel/fresh gas mixture present in the combustion chamber to first flow out of the combustion chamber into the antechamber. The fuel/fresh gas mixture is then ignited in the prechamber by means of the spark plug, whereupon the ignited mixture enters the combustion chamber from the prechamber and the mixture present there also ignites.

In principle, the antechamber can have any desired configuration. For example, the antechamber can be part of the spark plug and this can accordingly be in the form of an antechamber spark plug. However, it can also be provided that the antechamber is configured on or in the cylinder roof, preferably by the cylinder head, or that it is formed by a separate component. In these cases, the spark plug protrudes into the antechamber, so that its ignition electrode or ignition point is in the antechamber. The use of the antechamber has advantages above all when the internal combustion engine is under high load, in particular a particularly high level of efficiency is achieved there.

However, a change in the fluid in the antechamber is based solely on passive effects during the introduction of the fresh gas into the combustion chamber and/or during the discharge of the exhaust gas from the combustion chamber. For this reason, to further increase the efficiency of the internal combustion engine, the antechamber should be actively flushed with the flushing gas. The scavenging preferably takes place after the mixture present in the prechamber and the combustion chamber has been ignited, in particular during or after the discharge of the exhaust gas from the combustion chamber, and before the subsequent provision of the fuel/fresh gas mixture for ignition in the prechamber, in particular before introduction of the fuel into the combustion chamber. Fresh gas, in particular fresh air, is preferably used as the flushing gas. However, it can also be provided that the flushing gas is a mixture of fuel and fresh gas.

The scavenging gas introduction opening, which is fluidically connected to the scavenging gas line, is present for introducing the scavenging gas into the antechamber. In terms of flow, the scavenging gas line is connected to the antechamber via the scavenging gas introduction opening, so that scavenging gas supplied through the scavenging gas line passes through the scavenging gas introduction opening into the antechamber. In order to enable a particularly effective scavenging of the prechamber, in particular scavenging of the ignition area, the scavenging gas introduction opening opens into the prechamber on that side of the ignition electrode which faces away from the combustion chamber—seen in the axial direction with respect to the longitudinal central axis of the spark plug.

This means in particular that—again seen in the axial direction with respect to the longitudinal center axis—the scavenging gas introduction opening opens into the antechamber on the side of the ignition electrode facing away from the overflow opening or the overflow openings. This allows the flushing gas to flow past the ignition electrode during flushing and in particular to flow through the ignition area. Consequently, in terms of flow, the ignition electrode or the ignition area lies between the flushing gas introduction opening or the point at which it flows into the antechamber and the overflow opening or the overflow openings. By flushing the antechamber, any exhaust gas that may still be present in it is discharged from it, so that a particularly easily ignitable mixture is then made available in it. This improves the efficiency of the internal combustion engine.

A further development of the invention provides that an insulator protruding into the prechamber extends from a base body of the spark plug and carries the ignition electrode on its side facing away from the base body, with the flushing gas introduction opening being at a distance from the ignition electrode and overlapping the insulator in the antechamber opens. To this extent, the spark plug has at least the base body, the insulator and the ignition electrode. The ignition electrode is connected to the base body via the insulator, preferably exclusively via the insulator. In the radial direction, the insulator preferably has consistently smaller dimensions than the base body. In particular, the greatest diameter of the insulator over the extent of the insulator in the axial direction is smaller than the greatest diameter of the base body over its extent in the axial direction. In particular, this means that a spark plug shaft in which the spark plug is arranged is completely filled by the spark plug in the radial direction, whereas the insulator and the ignition electrode only take up part of the cross section of the spark plug shaft.

The scavenging gas introduction opening opens into the antechamber at a distance from the ignition electrode, namely on its side facing away from the combustion chamber or the overflow opening or the overflow openings. In addition, viewed in the axial direction with respect to the longitudinal center axis, the opening takes place in the area of the insulator, ie in overlap with the insulator. This leads to the flushing gas flowing around the insulator, so that the area of the antechamber around the insulator is also effectively flushed with the flushing gas and any exhaust gas still present there is effectively discharged.

The invention provides that the spark plug and the prechamber are arranged at least in regions in a spark plug shaft of the internal combustion engine that has an internal thread, with the scavenging gas introduction opening being arranged in the axial direction so as to overlap the internal thread and/or the scavenging gas line to overlap the internal thread on the scavenging gas introduction opening is fluidically connected. The spark plug shaft is used to accommodate the spark plug and the prechamber. In this respect, the spark plug shaft opens into the combustion chamber or the cylinder on one side.

The spark plug shaft is particularly preferably designed as a stepped recess, so that it has a section with a smaller diameter on its side facing the combustion chamber and a section with a larger diameter on its side facing away from the combustion chamber. This creates a contact shoulder against which the spark plug and/or a prechamber wall delimiting the prechamber rests. The investment school ter prevents displacement of the spark plug or the pre-chamber wall in the direction of the combustion chamber.

To fasten the spark plug and/or the antechamber wall, the spark plug shaft has the internal thread into which the spark plug or the antechamber wall is screwed. In order to achieve the most compact configuration possible for the arrangement of spark plug and prechamber, the scavenging gas introduction opening is designed to overlap with the internal thread, as seen in the axial direction. This means that—again viewed in the axial direction—the flushing gas introduction opening opens into the antechamber in the area of the internal thread. Additionally or alternatively, the scavenging gas line is connected to the scavenging gas introduction opening so that the internal thread overlaps. This means that there is a fluidic connection between the scavenging gas line and the scavenging gas introduction opening, seen in the axial direction, in the area of the internal thread or in overlapping relationship with the internal thread. The configuration of the internal combustion engine described is distinguished by a particularly compact arrangement of the spark plug and prechamber in the axial direction.

A further development of the invention provides that the scavenging gas line opens into the spark plug shaft via a scavenging gas line opening that penetrates the internal thread and the scavenging gas introduction opening is arranged to overlap with the scavenging gas line opening, or that the scavenging gas line opens into an annular chamber that penetrates through the internal thread and encompasses the spark plug, with which the Purge gas inlet opening is overlapped. The scavenging gas line opens into the spark plug shaft, forming the scavenging gas line opening. Viewed in the axial direction, the scavenging gas line outlet opening overlaps the internal thread, ie penetrates through it.

In order to create the fluidic connection between the scavenging gas line and the scavenging gas inlet opening, the spark plug or the antechamber wall is arranged in the spark plug shaft in such a way that the scavenging gas inlet opening and the scavenging gas line orifice overlap. The flow connection between the scavenging gas line and the scavenging gas introduction opening is sealed in the axial direction by the spark plug or the antechamber wall resting against a wall delimiting the spark plug shaft or against the internal thread.

As an alternative to the scavenging gas line orifice passing through the internal thread, the spark plug is encompassed by the annular chamber. The annular chamber is to be understood as meaning an annular chamber which has the same or approximately the same dimensions in the axial direction as the flushing gas introduction opening. The dimensions of the annular chamber in the axial direction are preferably at least 50%, at least 75% or at least 100% and/or at most 150%, at most 125% or at most 100% of the dimensions of the flushing gas introduction opening in the same direction.

The annular chamber passes through the internal thread in the direction of the scavenging gas introduction opening, namely in such a way that the scavenging gas line is fluidically connected to the scavenging gas introduction opening via the annular chamber. For this purpose, the flushing gas introduction opening overlaps with the annular chamber. The annular chamber preferably overlaps the flushing gas introduction opening completely, at least in the axial direction, in order to avoid possible pressure losses. In particular, the annular chamber ensures that the flushing gas calms down before it enters the antechamber.

A further development of the invention provides that the prechamber is delimited outwards in the radial direction by a prechamber wall which extends from the spark plug or forms a prechamber insert spaced apart from the spark plug. The antechamber wall starts, for example, from the base body of the spark plug or is at least attached to it. In this case, the antechamber wall completely encloses the insulator, namely starting from the base body up to the ignition electrode. In such a configuration, the spark plug is preferably in the form of a pre-chamber spark plug, in which the pre-chamber is already integrated as a result of the arrangement of the pre-chamber wall on the base body. This enables the use of inexpensive standard components. For example, a conventional prechamber spark plug is provided and the scavenging gas introduction opening is subsequently produced in it or in the prechamber wall.

Alternatively, the antechamber wall is located at a distance from the spark plug or its base body in the axial direction. The insulator of the spark plug extending from the base body extends into the prechamber delimited by the prechamber wall, so that the ignition electrode is present in the region of the prechamber wall, in particular overlapping with it in the axial direction. The gap is formed between the spark plug and its base body to space it away from the antechamber wall.

In this case, the spark plug and the antechamber wall are preferably present as separate components, which are also installed separately from one another in the ignition candle shaft to be introduced. For example, first the antechamber wall is arranged in the spark plug well, in particular screwed into it, and only then is the spark plug. With such a configuration, there is indeed an increased assembly outlay, but no separate production of the flushing gas introduction opening is necessary, since this is already formed by the gap. Due to the use of the gap, a particularly uniform inflow of the flushing gas into the antechamber is also achieved.

A development of the invention provides that the antechamber wall has a recess on its side facing away from the antechamber in the radial direction, via which a flow connection is established between the scavenging gas line and the scavenging gas introduction opening. The recess can be in the form of a depression which only partially passes through the antechamber wall in the radial inward direction, but is open at the edge in the radial outward direction. Alternatively, the recess is in the form of an opening which extends completely through the antechamber wall in the radial direction.

In any case, the flow connection between the scavenging gas line and the scavenging gas introduction opening is established via the recess, which openings are arranged offset relative to one another in the axial direction. In particular, the scavenging gas line opens into the spark plug shaft at a distance from the scavenging gas introduction opening in the axial direction. In other words, the scavenging gas line opening is offset in the axial direction relative to the scavenging gas introduction opening.

The scavenging gas is routed in a targeted manner via the recess from the scavenging gas line opening to the scavenging gas introduction opening. The configuration of the recess as a depression is implemented in particular if the insulator is arranged at a distance from the antechamber wall in the radial direction. However, if the insulator extends in the radial direction at least in sections as far as the antechamber wall, the opening can be present since the recess is closed by the insulator on its side facing the antechamber. In any case, a streamlined routing of the flushing gas is realized.

A further development of the invention provides that a further scavenging gas introduction opening opens into the prechamber on the side of the ignition electrode facing away from the combustion chamber in the axial direction with respect to the longitudinal center axis of the spark plug, the further scavenging gas introduction opening being closed by a spark plug well wall delimiting the spark plug well in the radial direction outwards or via it the annular chamber is fluidically connected to the flushing gas line. The further purge gas introduction port is in addition to the further purge gas introduction port. For example, the scavenging gas introduction opening and the further scavenging gas introduction opening are offset in relation to one another in the circumferential direction with respect to the longitudinal central axis, in particular arranged evenly distributed. There can be only a single further scavenging gas introduction opening or else a plurality of scavenging gas introduction openings.

The further scavenging gas introduction opening or the several further scavenging gas introduction openings are configured analogously to the scavenging gas introduction opening, so that in principle reference is made to the corresponding explanations. However, the further scavenging gas introduction opening is arranged in such a way that it is closed by the spark plug shaft wall, ie it is not in flow connection with the scavenging gas line, or at most it is via the antechamber itself. In such a configuration, the further scavenging gas introduction opening enables flexible use of the spark plug, since when the spark plug is arranged in the spark plug shaft, one of the scavenging gas introduction openings, i.e. either the scavenging gas introduction opening or the further scavenging gas introduction opening, is always fluidly connected to the scavenging gas line, so that one of the scavenging gas introduction openings is always Purge gas introduction opening and another than further purge gas introduction opening.

Alternatively, it is provided that the further scavenging gas introduction opening is fluidically connected to the annular chamber in addition to the scavenging gas introduction opening. In this case, the flushing gas can flow into the antechamber in a particularly streamlined and uniform manner. Overall, the described embodiment of the internal combustion engine achieves simple assembly or a particularly streamlined flow of scavenging gas.

A development of the invention provides that the flushing gas introduction opening opens into an annular gap of the antechamber, which is delimited in the radial direction inward by the insulator and in the radial direction outward by the antechamber wall. Viewed in the axial direction, the annular gap extends from the base body of the spark plug to the ignition electrode. For example, a flow cross-sectional area of the annular gap also increases starting from the base body in the direction of the ignition electrode. However, it can also be provided that the flow cross-sectional area of the annular gap remains the same over the extent of the insulator. The introduction of the scavenging gas into the annular gap via the scavenging gas introduction opening enables a particularly effective scavenging of the antechamber, since the scavenging gas flows through it to a large extent.

A development of the invention provides that the spark plug and/or the antechamber wall have an external thread which engages in the internal thread of the spark plug shaft. If the spark plug and the antechamber wall are present as a unit, ie as an antechamber spark plug, the external thread can be designed either on the spark plug or on the antechamber wall or on both. If the spark plug and the pre-chamber wall are separate elements, they each have the external thread. The spark plug or the antechamber wall is fastened in the spark plug shaft using the external thread, which for this purpose interacts with the internal thread of the spark plug shaft. As a result, a reliable attachment of the elements mentioned is realized.

The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and/or shown in the figures, can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention. The invention is therefore also to be regarded as encompassing embodiments which are not explicitly shown or explained in the description and/or the figures, but emerge from the explained embodiments or can be derived from them.

• 1 eine schematische Schnittdarstellung durch eine Brennkraftmaschine, welche eine Zündkerze und eine eine Zündelektrode der Zündkerze aufnehmende Vorkammer aufweist, sowie
• 2 schematische Darstellungen von unterschiedlichen Ausführungsformen der Zündkerze und der Vorkammer.

The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the drawing, without restricting the invention. This shows:

• 1 a schematic sectional view through an internal combustion engine, which has a spark plug and an ignition electrode of the spark plug receiving pre-chamber, and
• 2 schematic representations of different embodiments of the spark plug and the prechamber.

The 1 shows an extremely schematic representation of an internal combustion engine 1, namely a schematic sectional view through a cylinder 2 of the internal combustion engine 1. In the cylinder 2 there is a combustion chamber 3, in which gas exchange channels 4 and 5 via gas exchange valves 6 and 7 open or are connected. The gas exchange channel 4 is present as an inlet channel and the gas exchange channel 5 as an outlet channel. Correspondingly, the gas exchange valve 6 can also be referred to as an inlet valve and the gas exchange valve 7 can also be referred to as an outlet valve.

To ignite a fuel/fresh gas mixture present in combustion chamber 3 , internal combustion engine 1 has a spark plug 8 whose ignition electrode is arranged in an antechamber 10 that is connected to combustion chamber 3 via at least one overflow opening 11 . The ignition electrode 9 is present as a center electrode. In addition to ignition electrode 9, spark plug 8 has at least one further ignition electrode 12, which is arranged at a distance from ignition electrode 9 in the radial direction and/or in the axial direction with respect to a longitudinal center axis 13 of spark plug 8. Between the ignition electrode 9 and the further ignition electrode 12 there is an ignition point of the spark plug 8 at which an ignition spark for igniting the fuel/fresh gas mixture is generated at least temporarily.

The ignition electrode 9 is located on an insulator 15 which extends from a base body 16 of the spark plug 8 . Starting from the base body 16 , the insulator 15 extends in the axial direction in the direction of the combustion chamber 3 , through the antechamber 10 . It is now provided that the antechamber 10 is flushed at least temporarily with a flushing gas. The scavenging gas is supplied via a scavenging gas line 17 which is fluidically connected to the antechamber 10 via a scavenging gas introduction opening 18 . A flushing gas valve 19 is preferably arranged in the flushing gas line 17 , by means of which a volume flow or mass flow of the flushing gas through the flushing gas line 17 can be adjusted. The flushing gas valve 19 is present, for example, as a check valve or alternatively as a control valve, for example as a solenoid valve.

The 2 shows schematic representations of different embodiments of the spark plug 8 and the prechamber 10. In an upper row, a first embodiment is shown on the left, a second embodiment is shown in the middle, and a third embodiment is shown on the right. In a bottom row, a fourth embodiment is shown on the left, a fifth embodiment in the middle, and a sixth embodiment on the right, each schematically. In the first embodiment, the spark plug 8 is designed as a prechamber spark plug. Correspondingly, a direction facing away from the prechamber 10 in the radial direction outwards and in the axial direction from the spark plug 8 is delimited by a prechamber wall 20 which starts directly from the base body 16 .

In the exemplary embodiment shown, the antechamber wall 20 protrudes slightly into the combustion chamber 3 . However, it can also be provided that the antechamber wall 20 is completely accommodated in a spark plug well 21 . The spark plug shaft 21 is in the form of a stepped recess, so that a contact shoulder 22 is formed is on which the spark plug 8 is supported in the axial direction in the direction of the combustion chamber 3 . The spark plug shaft 21 has an internal thread 23 which interacts with an external thread 24 of the antechamber wall 20 in order to hold the spark plug 8 in the spark plug shaft 21 .

For the fluidic connection of the antechamber 10 to the scavenging gas line 17 , the scavenging gas introduction opening 18 overlaps with a scavenging gas line orifice opening 25 which penetrates the internal thread 23 . The insulator 15 (not visible here) extends in the axial direction, starting from the base body 16 and beyond the scavenging gas introduction opening 18, so that the ignition electrode 9 is on the side of the scavenging gas introduction opening 18 facing away from the base body 16 when viewed in the axial direction. This ensures a reliable flow through large areas of the antechamber 10 .

The second embodiment is similar to the first embodiment, so that reference is made to the above explanations and only the differences are discussed below. These lie in the fact that in addition to the scavenging gas introduction opening 18 there is a further scavenging gas introduction opening 26 . This is used for flexible use of the spark plug 8 or the antechamber wall 20 , since it is not necessary to precisely set a rotational angle position so that either the scavenging gas introduction opening 18 or the further scavenging gas introduction opening 26 overlaps with the scavenging gas line 17 .

The third embodiment corresponds to the first embodiment or the second embodiment with the difference that the antechamber 10 is surrounded by an annular chamber 27 into which the flushing gas line 17 opens. The flushing gas line 17 is fluidically connected both to the flushing gas introduction opening 18 and to the further flushing gas introduction opening 26 (if present) via the annular chamber 27 . Accordingly, a uniform introduction of the flushing gas into the antechamber 10 is possible.

In principle, reference is also made to the above explanations for the fourth embodiment. The difference, for example from the first embodiment, lies in the spacing of prechamber wall 20 from base body 16 of spark plug 8, so that only insulator 15 and ignition electrode 9 of spark plug 8 overlap prechamber wall 20 or engage in prechamber 10 . As a result, a gap 28 is formed between the base body 16 and the antechamber wall 20, through which the insulator 15 passes completely in the axial direction. This gap 28 forms the scavenging gas introduction opening 18 . It overlaps the scavenging gas line opening 25 so that scavenging gas supplied through it via the scavenging gas line 17 can flow into the antechamber 10 .

The fifth embodiment in turn corresponds to the fourth embodiment, with the difference that the annular chamber 27 is present analogously to the third embodiment.

The sixth embodiment is similar to the third embodiment, so that reference is made to the corresponding explanations and only the differences are discussed below. These lie in the fact that the scavenging gas introduction opening 18 or further scavenging gas introduction openings 26 are arranged at a distance from the scavenging gas line opening 25 and/or the annular chamber 27 in the axial direction. In order to connect the scavenging gas introduction opening 18 and the at least one further scavenging gas introduction opening 26 to the scavenging gas line 17 in terms of flow, the antechamber wall 20 has a recess 29, in the exemplary embodiment shown here several recesses 29, which extend in the axial direction and the distance between the scavenging gas line opening 25 or the annular chamber 27 and the scavenging gas introduction opening 18 and the at least one further scavenging gas introduction opening 26 bridged.

In order to simultaneously ensure that spark plug 8 is reliably fastened in spark plug shaft 21, recess 29 is interrupted in the circumferential direction, i.e. it only extends over part of the circumference of spark plug 8 or prechamber wall 20.

The configuration of the internal combustion engine 1 described has the advantage that extensive scavenging of the antechamber 10 is achieved through the corresponding arrangement of the scavenging gas introduction opening 18 . At the same time, the arrangement of the spark plug 8 and prechamber 10 is kept extremely compact by introducing the flushing gas via the internal thread 23 of the spark plug shaft 21 . In addition, a conventional prechamber spark plug can be used and the scavenging gas introduction opening 18 can be subsequently introduced into it, so that production costs are kept low.

Reference List

1

internal combustion engine

2

cylinder

3

combustion chamber

4

gas exchange channel

5

gas exchange channel

6

gas exchange valve

7

gas exchange valve

8th

spark plug

9

ignition electrode

10

antechamber

11

overflow opening

12

additional ignition electrode

13

longitudinal central axis

14

ignition point

15

insulator

16

body

17

purge gas line

18

purge gas injection port

19

purge gas valve

20

antechamber wall

21

spark plug well

22

contact shoulder

23

inner thread

24

external thread

25

purge gas line orifice

26

further purge gas inlet opening

27

ring chamber

28

gap

29

recess

Claims (9)

Internal combustion engine (1) with a combustion chamber (3) and a spark plug (8) for igniting a fuel/fresh gas mixture located in the combustion chamber (3), an ignition electrode (9) of the spark plug (8) being connected in a flow-technical manner to the combustion chamber ( 3) connected to the antechamber (10), wherein a scavenging gas introduction opening (18), through which scavenging gas supplied via a scavenging gas line (17) can be introduced into the antechamber (10), is arranged in the axial direction with respect to a longitudinal center axis (13) of the spark plug (8 ) opens into the prechamber (10) on the side of the ignition electrode (9) facing away from the combustion chamber (3), characterized in that the spark plug (8) and the prechamber (10) are at least partially located in a spark plug shaft (21) having an internal thread (23) of the internal combustion engine (1), the scavenging gas introduction opening (18) being arranged in the axial direction so that they overlap the internal thread (23) and/or the scavenging gas line (17) so as to overlap the internal thread (23) to the scavenging gas introduction opening (18) in terms of flow connected. internal combustion engine claim 1 , characterized in that an insulator (15) protruding into the prechamber (10) extends from a base body (16) of the spark plug (8) and carries the ignition electrode (9) on its side facing away from the base body (16), with the axial Seen in the direction the purge gas introduction opening (18) opens into the antechamber (10) at a distance from the ignition electrode (9) and overlapping with the insulator (15). Internal combustion engine according to one of the preceding claims, characterized in that the scavenging gas line (17) opens into the spark plug shaft (21) via a scavenging gas line opening (25) which penetrates the internal thread (23) and the scavenging gas introduction opening (18) overlaps the scavenging gas line opening (25). or that the scavenging gas line (17) opens into an annular chamber (27) which extends through the internal thread (23) and surrounds the spark plug (8) and with which the scavenging gas introduction opening (18) overlaps. Internal combustion engine according to one of the preceding claims, characterized in that the pre-chamber (10) is delimited outwards in the radial direction by a pre-chamber wall (20) which starts from the spark plug (8) or forms a pre-chamber insert at a distance from the spark plug (8). internal combustion engine claim 4 , characterized in that the flushing gas introduction opening (18) is present in the antechamber wall (20) or is formed by a gap (28) present between the spark plug (8) and the antechamber wall (20). internal combustion engine claim 4 or 5 , characterized in that the antechamber wall (20) has a recess (29) on its side facing away from the antechamber (10) in the radial direction, via which a flow connection is established between the scavenging gas line (17) and the scavenging gas introduction opening (18). internal combustion engine claim 1 or 3 , characterized in that a further scavenging gas introduction opening (18) opens into the antechamber (10) on the side of the ignition electrode (9) facing away from the combustion chamber (3) in the axial direction with respect to the longitudinal center axis (13) of the spark plug (8), the further scavenging gas introduction opening (26) is closed by a spark plug shaft wall delimiting the spark plug shaft (21) outwards in the radial direction, or via the ring chamber (27) is fluidically connected to the flushing gas line (17). internal combustion engine claim 2 and 3 , characterized in that the flushing gas introduction opening (18) opens into an annular gap of the antechamber (10) which is delimited in the radial direction inward by the insulator (15) and in the radial direction outward by the antechamber wall (20). internal combustion engine claim 1 or 4 , characterized in that the spark plug (8) and/or the antechamber wall (20) have an external thread (24) which engages in the internal thread (23) of the spark plug shaft (21).

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