Pre-chamber spark plug for a combustion chamber of an internal combustion engine, internal combustion engine and motor vehicle

Abstract

Prechamber spark plug (10) for a combustion chamber of an internal combustion engine, with a prechamber (12) having a plurality of openings (16, B1, B2), which can be fluidically connected to the combustion chamber via the openings (16, B1, B2), via which a fuel-air mixture can be introduced from the combustion chamber into the prechamber (12), wherein the respective opening (16, B1, B2) has a respective flow cross-section (Q) through which the fuel-air mixture can flow, wherein, with reference to an imaginary plane (E) running along an imaginary axis (A) and dividing the prechamber (12) into two equal halves (H1, H2), the sum of the flow cross-sections (Q) of the openings (B1) arranged in a first of the halves (H1, H2) is greater than the sum of the flow cross-sections (Q) of the openings (B2) arranged in the second half (H2), and wherein the Openings (16) are rotationally asymmetrical around the axis (A), characterized in thatthat the flow cross-sections of at least two of the openings (16) differ from each other in terms of their shape.,

Description

The invention relates to a pre-chamber spark plug for a combustion chamber of an internal combustion engine, in particular of a motor vehicle, according to the preamble of patent claim 1.EP 2 700 796 A1 discloses a pre-combustion chamber tip of a pre-combustion chamber arrangement of an internal combustion engine. Furthermore, a pre-combustion chamber is known from US 2013 / 0 055 986 A1. DE 10 2018 117 726 A1 discloses an internal combustion engine having a spark plug which has a spark generating part. JP 2012-211 594 A discloses a pre-chamber spark plug. DE 10 2018 106 213 A1 discloses an internal combustion engine having a main combustion chamber which is arranged between a cylinder head and a piston which faces the cylinder head. Furthermore, DE 10 2018 007 093 A1 discloses a pre-chamber spark plug for a combustion chamber of an internal combustion engine.It is an object of the present invention to provide a pre-chamber spark plug for a combustion chamber of an internal combustion engine, an internal combustion engine having at least one such pre-chamber spark plug and a motor vehicle, so that particularly advantageous operation of the internal combustion engine can be realized.This object is achieved by a pre-chamber spark plug having the features of claim 1, by an internal combustion engine having the features of claim 8 and by a motor vehicle having the features of claim 10. Advantageous embodiments with expedient developments of the invention are specified in the other claims.A first aspect of the invention relates to a pre-chamber spark plug for a combustion chamber of an internal combustion engine, also referred to as an internal combustion engine, in particular for a motor vehicle. The pre-chamber spark plug has a pre-chamber with several openings, for example, designed as through openings, via which the pre-chamber is fluidically connectable or connected to the combustion chamber. For example, the respective opening is designed as a bore. In particular, the opening can run straight or straight, preferably over its complete extent. A fuel-air mixture, also referred to simply as a mixture, can be introduced from the combustion chamber into the prechamber via the respective opening. For example, at least one ignition spark can be generated in the prechamber. For this purpose, the pre-chamber spark plug comprises, for example, at least one electrode device which is arranged at least partially in the pre-chamber. By means of the electrode device, the aforementioned ignition spark can be generated in the prechamber. By means of the ignition spark, the fuel-air mixture, which has flowed into the prechamber via the openings, can be ignited or ignited and subsequently burned, so that, for example, flames or burning torches, which result from the ignition of the mixture, can flow out of the prechamber via the openings and reach the combustion chamber. As a result, the mixture remaining in the combustion chamber is ignited in the combustion chamber.The respective opening has a respective flow cross section through which the fuel-air mixture or the respective torch can flow. The respective flow cross section is thus a surface through which the mixture can flow or has a surface or a surface area and through which the mixture can flow.In order to be able to realize a particularly advantageous operation of the internal combustion engine, it is provided according to the invention that, with respect to an imaginary or virtual plane which runs along an imaginary axis and divides the prechamber into exactly two equally sized halves, first of the openings are arranged in a first of the halves and second of the openings are arranged in the second half. The axis is preferably a straight line. Furthermore, it is provided that the sum of the flow cross sections of the first openings arranged in the half is greater than the sum of the flow cross sections of the second openings arranged in the second half. For example, the openings are arranged along an imaginary or virtual circle, the imaginary or virtual center point of which lies on the imaginary or virtual axis, so that, for example, the openings are arranged successively around the axis along the circle. This can be understood in particular to mean that respective centers or geometric centers of gravity, in particular centroids, of the openings or the flow cross sections are arranged on the imaginary circle and along the circle, in particular in succession. For example, the imaginary plane divides the circle into two circle halves of equal size or into two parts of equal size or of equal length, wherein for example a first of the circle halves is arranged, in particular completely, in the first half, which is also referred to as the first chamber half, and wherein for example the second circle half is arranged, in particular completely, in the second half, of the prechamber, which is also referred to as the second chamber half.For example, the first openings arranged in the first half are arranged on the first circle half, while the second openings arranged in the second half are arranged on the second circle half. In this case, the sum of the flow cross sections of the openings arranged on the first circle half is preferably greater than the sum of the flow cross sections of the openings arranged on the second circle half.Furthermore, it is provided according to the invention that the openings are configured rotationally asymmetrical about the axis, i.e. with respect to the axis. This is to be understood in particular, for example, as meaning that the openings are arranged around the axis and thus, in the circumferential direction of the prechamber or of the prechamber spark plug running around the axis, as a whole asymmetrically, that is to say distributed non-uniformly. Alternatively or additionally, the feature that the openings are configured or formed rotationally asymmetrical around the axis can be understood to mean that at least two of the openings differ from one another in their geometry, in particular in the geometry of their respective flow cross section, and in this case have a rotationally asymmetrical sequence, in particular about the axis. This means in particular that the flow cross sections of these at least two openings differ from one another, in particular with regard to their size, i.e. area or surface area, wherein the at least two openings or preferably all openings have a rotationally asymmetrical sequence around the axis. This means in particular that the at least two openings or preferably all openings follow one another non-uniformly or unaligned around the axis, i.e. not according to a regular sequence. Furthermore, it is provided according to the invention that the flow cross sections of at least two of the openings ( 16) differ from one another with regard to their shape.The different sums of the flow cross sections can cause or configure the openings to cause a tumble-shaped flow of the fuel-air mixture flowing into the prechamber via the openings. In other words, during a fired operation of the internal combustion engine, the openings, in particular also by virtue of their arrangement and / or their number and / or their geometry and according to the invention in that the sum of the or all flow cross sections of the openings arranged in the first half is greater than the sum of the or all flow cross sections of the openings arranged in the second half, bring about an at least substantially tumble-shaped flow of the fuel-air mixture, which is also simply referred to as a mixture and flows through the opening and thus flows from the combustion chamber into the prechamber. Again in other words, the openings, which are designed, for example, as through openings, impart an at least substantially tumble-shaped and thus roller-shaped flow to the mixture flowing through the openings and thus flowing from the combustion chamber into the prechamber, which is also referred to as tumble flow, so that a particularly advantageous operation of the prechamber spark plug and thus of the internal combustion engine can be realized overall.Since the sum of the flow cross sections of the openings arranged in the first half is greater than the sum of the flow cross sections of the openings arranged in the second half, it is provided according to the invention that the openings, which are designed, for example, as bores, are designed to be rotationally asymmetrical with respect to the stated axis or about the axis. This rotationally asymmetrical configuration can comprise or contain a respective positioning and / or the flow cross section of the respective opening, which is also referred to as a cross-sectional area or has a cross-sectional area.In contrast to a rotationally symmetrical arrangement of the openings about the axis and in contrast to a rotationally symmetrical flow which possibly results therefrom and extends, for example, in a helical or ring-like manner about a main axis or a longitudinal axis of the prechamber, the tumble-shaped flow is a roller-shaped flow which is also referred to as roller flow and extends, for example, at least partially in a plane or runs in a plane in which the main axis lies. The aforementioned main axis or longitudinal axis can be the aforementioned imaginary axis.The flow in the form of a tumble, also referred to as tumble flow, positively influences the combustion in the prechamber in a plurality of ways, as a result of which a particularly large working range can be realized in the prechamber. Firstly, there is better scavenging of the residual gas in the region of the spark plug gap, resulting in more stable ignition. In comparison with conventional spark plugs, there is a more favorable convection of the initial flame kernel in the direction of the openings, which are also referred to as nozzles or are designed as nozzles. By means of better scavenging and by means of the more favorable convection, a more combustion-favorable configuration of the electrode device of the spark plug, which is also simply referred to as an electrode, can be achieved, in particular with regard to a smaller penetration depth of the electrode, which is designed as a ground electrode, for example. This results in a lower surface area, which in turn results in lower wall heat losses. This allows the tendency for pre-ignition to be reduced in comparison with conventional pre-chamber spark plugs.The aforementioned respective flow cross section is to be understood in particular as the respective smallest or smallest flow cross section or opening cross section of the respective opening through which the mixture can flow. In conventional pre-chamber spark plugs, the openings, in particular because of their rotationally symmetrical arrangement, bring about an at least substantially rotationally symmetrical flow of the mixture flowing through the opening and thus flowing from the combustion chamber into the pre-chamber. A disadvantage here is that the initial flame kernel is not connected or is connected away from the openings, also referred to as prechamber nozzles.In order to ensure sufficiently low residual gas contents in the region of the spark plug gap in conventional pre-chamber spark plugs, a long electrode must be used which projects deeply into the pre-chamber. This results in a cracked surface in the pre-chamber and a large damage volume. The aforementioned problems and disadvantages can be avoided in the pre-chamber spark plug according to the invention.The combustion in the pre-chamber is stabilized and improved by the tumble flow. This increases the working area of the pre-chamber, so that a more stable ignition at idle and a lower risk of pre-ignition at full load can be realized. Furthermore, the better combustion results in a greater increase in pressure in the prechamber and consequently a deeper torch penetration depth into the combustion chamber. This also improves the combustion in the combustion chamber, also referred to as the main combustion chamber. The torch penetration depth is understood to mean a distance, a path or a depth that the respective torch penetrates into the prechamber. As described above, the respective torch results from the mixture in the pre-chamber being ignited and subsequently burned.Further findings on which the invention is based are that prechamber spark plugs can be differentiated according to the flow structure in the prechamber. In this case, it is possible to distinguish, for example, between structureless (chaotic) flow shapes in the prechamber and rotationally symmetrical flow shapes, in particular according to the prior art. The flow structure is determined by a corresponding arrangement and configuration of the openings. The arrangement or configuration of the openings is rotationally symmetrical about the aforementioned axis, which is for example one or the main axis of the prechamber, for rotationally symmetrical flow structures according to the prior art. In contrast to such a rotationally symmetrical configuration of the openings, according to the invention, a rotationally asymmetrical configuration of the openings with respect to the axis is provided, so that the tumble-shaped flow of the mixture is effected or can be effected. In order to be able to realize particularly advantageous flow conditions in the prechamber and thus a particularly operation, it is provided in an embodiment of the invention that the axis runs in the direction of longitudinal extent of the prechamber. In other words, the axis and thus the plane in which the axis extends run parallel to the direction of longitudinal extent of the prechamber or coincide with the direction of longitudinal extent of the prechamber.A further embodiment is characterized in that the prechamber is designed to be rotationally symmetrical with respect to the axis, whereby particularly advantageous flow conditions and thus particularly advantageous operation can be ensured.A further embodiment is distinguished in that the or all flow cross sections of the openings arranged in the first half are larger than the or all flow cross sections of the openings arranged in the second half. As a result, particularly advantageous flow conditions and thus particularly advantageous operation can be ensured.In a particularly advantageous embodiment of the invention, it is provided that a or the number of or all the openings arranged in the first half is greater than a or the number of or all the openings arranged in the second half. As a result, an advantageously tumble-shaped flow can be realized in a particularly advantageous manner, so that a particularly advantageous operation can be realized.In order to be able to realize particularly advantageous operation in a particularly simple and reliable manner, it is provided in a further embodiment of the invention that the or all openings are circular, so that the openings have a respective diameter. In this case, it is provided in particular that the or all flow cross sections are each circular and thus have a respective or the respective diameter. In this case, it is preferably provided that the or all diameters of the openings arranged in the first half are greater than the or all diameters of the openings arranged in the second half.Finally, it has been found to be particularly advantageous if the mean value of the flow cross sections of the openings arranged in the first half is greater than the mean value of the flow cross sections of the openings arranged in the second half. The mean value is preferably to be understood as the arithmetic mean value, also referred to as arithmetic mean, which results, for example, from the sum of the flow cross sections of the openings arranged in the respective half being divided, that is to say divided, by the number of openings arranged in the respective half.A second aspect of the invention relates to an internal combustion engine for a motor vehicle, preferably designed as a reciprocating piston engine, which may preferably be designed as a motor vehicle and very preferably as a passenger vehicle or else as a commercial vehicle. The internal combustion engine has at least one combustion chamber. The combustion chamber is, for example, partially delimited by a cylinder and by a piston of the internal combustion engine which is arranged in a translationally movable manner in the cylinder, wherein the cylinder is formed or delimited, for example, by an engine housing of the internal combustion engine which is in particular designed as a crankcase or cylinder crankcase. In addition, the combustion chamber is partially delimited, for example, by a combustion chamber roof which is formed, for example, by a cylinder head which is formed separately from the engine housing and is connected to the engine housing. The internal combustion engine also has at least one pre-chamber spark plug assigned to the combustion chamber, which is arranged, for example, at least partially in the combustion chamber. The pre-chamber spark plug comprises a pre-chamber having a plurality of openings via which the pre-chamber is fluidically connected to the combustion chamber, also referred to as the main combustion chamber. A fuel-air mixture, also referred to simply as a mixture, can be introduced or flowed from the combustion chamber into the prechamber via the openings. In other words, for example, the aforementioned fuel-air mixture is formed in the combustion chamber or the fuel-air mixture is introduced into the combustion chamber. For example, fuel, in particular liquid fuel, and air are introduced into the combustion chamber. For example, the fuel is injected directly into the combustion chamber. The aforementioned mixture comprises the air and the fuel that are introduced into the combustion chamber. At least a portion of the mixture from the combustion chamber can flow through the openings and thus flow into the prechamber via the openings. In the pre-chamber, the portion of the mixture may be ignited and burned, resulting in the above-described torching. The torch can then flow out of the pre-chamber via the openings and into the main combustion chamber and ignite the remaining mixture there. The respective opening has a respective flow cross section through which the mixture or the respective torch can flow.In order to be able to realize a particularly advantageous operation, it is provided according to the invention that, with respect to an imaginary plane running along an imaginary axis and dividing the prechamber into two equally large halves, the sum of the flow cross sections of the openings arranged in a first of the halves is greater than the sum of the flow cross sections of the openings arranged in the second half. In this case, the openings are configured rotationally asymmetrical about the axis. Advantages and advantageous configurations of the first aspect of the invention are to be regarded as advantages and advantageous configurations of the second aspect and vice versa. Furthermore, it is provided according to the invention that the flow cross sections of at least two of the openings ( 16) differ from one another with regard to their shape.In order to be able to realize a particularly advantageous operation of the internal combustion engine, it is provided in one embodiment of the second aspect of the invention that the internal combustion engine is designed as a reciprocating piston engine.A third aspect of the invention relates to a motor vehicle, preferably designed as a motor vehicle, which has an internal combustion engine according to the invention according to the second aspect of the invention. The motor vehicle can be driven by means of the internal combustion engine. Advantages and advantageous configurations of the first and second aspect of the invention are to be regarded as advantages and advantageous configurations of the third aspect of the invention and vice versa.Further advantages, features and details of the invention will become apparent from the following description of a preferred exemplary embodiment and with reference to the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.The drawing shows in: FIG. 1 shows a schematic and sectional side view of a pre-chamber spark plug according to the invention for a combustion chamber of an internal combustion engine of a motor vehicle; FIG. 2 shows a further schematic and sectional side view of the pre-chamber spark plug; and FIG. 3 shows a schematic view of the pre-chamber spark plug along a viewing direction denoted by B in FIG. 2.In the figures, identical or functionally identical elements are provided with identical reference symbols.FIGS. 1 and 2 each show, in a schematic and sectioned side view, a pre-chamber spark plug 10 for a combustion chamber, formed for example by a cylinder or formed as a cylinder or bounded by a cylinder, of an internal combustion engine, formed for example as a reciprocating piston engine, of a motor vehicle, in particular of a motor vehicle, such as a passenger car or commercial vehicle. The motor vehicle can be driven by means of the internal combustion engine. The pre-chamber spark plug 10 has at least or exactly one pre-chamber 12, the contour of which is designated by 14 in FIG. 1. The prechamber 12 has a plurality of openings 16, also referred to as nozzles and designed as through openings, via which the prechamber 12 is fluidically connectable or connected to the combustion chamber. In its completely produced state, the internal combustion engine has the aforementioned combustion chamber and the pre-chamber spark plug 10, so that in the completely produced state of the internal combustion engine the pre-chamber 12 is fluidically connected to the combustion chamber via the openings 16. As a result, a fuel-air mixture can flow from the combustion chamber at least partially through the openings 16 and thereby flow into the prechamber 12, so that at least a portion of the fuel-air mixture, which is also referred to simply as a mixture, can flow from the combustion chamber through the openings 16 and thus can flow or flows via the openings 16 into the prechamber 12.The pre-chamber spark plug 10 has at least one or more electrodes, wherein one of the electrodes of the pre-chamber spark plug 10 is recognizable in FIG. 1. The electrode 18 is, for example, a center electrode and is arranged at least partially in the prechamber 12. The pre-chamber spark plug 10 also has a second electrode 19, which is arranged, for example, as a ground electrode and at least partially in the pre-chamber 12. By means of the electrodes 18 and 19, at least one ignition spark can be generated in the pre-chamber 12, in particular within a respective working cycle of the internal combustion engine. By means of the ignition spark, the mixture which has flowed into the prechamber 12 and is consequently accommodated in the prechamber 12 can be ignited. Electrodes 18 and 19 define an ignition location for the ignition spark. For example, the ignition spark is generated at or in the ignition location. In other words, the ignition spark can be generated or provided at the ignition location in the prechamber 12 by means of the electrodes 18 and 19. By igniting the mixture in the pre-chamber 12, the mixture in the pre-chamber 12 is burnt. This results in burning factors which flow through the openings 16 and can therefore flow from the prechamber 12 into the combustion chamber via the openings 16. As a result, for example, the remaining mixture remaining in the combustion chamber is ignited.As can be seen, for example, from FIG. 2 using the example of one of the openings 16, the respective opening 16 or all of the openings 16 have a respective flow cross section Q through which the mixture or the respective torch can flow. The flow cross section Q is a surface or has a surface or a surface area, wherein the mixture or the torch can flow through the surface.It can be seen from FIGS. 1 and 2 that an imaginary plane E runs along an axis A which runs in the plane E. The axis A and thus the plane E extend in the direction of longitudinal extent of the prechamber 12 and thus of the prechamber spark plug 12, wherein the direction of longitudinal extent is illustrated by a double arrow 13. In other words, the axes A and the plane E run parallel to the direction of longitudinal extent of the prechamber 12 or the direction of longitudinal extent of the prechamber 12 coincides with the axis A and with the plane E. In this case, the imaginary plane E divides the prechamber 12 into exactly two identically sized halves H 1 and H 2. First of the openings 16 denoted by B 1 are now arranged in the first half H 1 and second of the openings 16 denoted by B 2 are arranged in the second half H 2. QIn order to be able to realize a particularly advantageous operation of the pre-chamber spark plug 10 and thus of the internal combustion engine overall, the sum of the flow cross sections Q of the first openings B 1 arranged in the first half H 1 is greater than the sum of the flow cross sections Q of the second openings B 2 arranged in the second half H 2.For example, the or all openings 16 of the prechamber 12 are arranged-as can be seen particularly well from FIG. 3-along an imaginary circle K, the center point M of which lies on the imaginary axis A. The plane E divides the imaginary circle K into exactly two circle halves of equal size, for example, wherein a first of the circle halves is arranged, in particular completely, in the first half H 1 and the second circle half is arranged, for example, in particular completely, in the second half H 2. It is conceivable that the sum of the flow cross sections Q of the first openings B 1 arranged on the first circle half is greater than the sum of the flow cross sections Q of the second openings B 2 arranged on the second circle half.In the exemplary embodiment shown in the figures, the axis A runs in the direction of longitudinal extent of the prechamber 12, wherein the axis A is a main axis of the prechamber 12, or the main axis of the prechamber 12, also referred to as the longitudinal axis or the longitudinal central axis. In this case, it is preferably provided that the prechamber 12 is configured rotationally symmetrically per se with respect to the axis A.In the exemplary embodiment shown in the figures, a number of the openings B 1 arranged on or in the first half H 1 is greater than a number of the openings B 2 arranged on or in the second half H 2. Here, the number of the openings B 1 is three, while the number of the openings B 2 is two. In addition, it is preferably provided that all flow cross sections Q of all openings B 1 are larger than all flow cross sections Q of all openings B 2. In addition, it is preferably provided that the mean value of the flow cross sections Q of the openings B 1 is greater than the mean value of the flow cross sections Q of the openings B 2. In other words, it is preferably provided that the average cross section of the opening B 1 is greater than the average cross section of the opening B 2. In the exemplary embodiment shown in the figures, the or all openings are circular, so that the or all openings have a respective diameter. Here, the or all diameters of the openings B 1 are larger than the or all diameters of the openings B 2.In particular, it is provided that the number and the diameters of the openings B 1 are greater than the number and the diameters of the opening B 2. The respective opening 16 is designed as a bore in the present case. In addition, the respective opening 16 runs straight or straight over its entire extent. Due to the described configuration of the openings 16, the openings 16 are designed to bring about a tumble-shaped flow, which is illustrated by arrows in FIG. 1 and is also referred to as a roller-shaped flow or roller flow, of the mixture flowing into the prechamber 12 via the openings 16. In particular, the arrows shown in FIG. 1 illustrate a contour of the tumble-shaped flow, also referred to as flow contour.The axis A, which is embodied in the present case as a main axis, runs in a plane, also referred to as a roller plane, around whose plane normal the tumble-shaped flow runs. For example, the plane denoted by E extends perpendicularly to this plane of the roll. As a result of the tumble-shaped flow, a volume V of the prechamber 12, also referred to as damage volume, can be kept particularly low, so that a particularly large working range of the prechamber spark plug 10 can be ensured. In FIG. 2, respective axes of the respective openings 16 are denoted by 20. For example, the respective opening 16 is rotationally symmetrical with respect to its respective axis 20 and is in this case, for example, circular, such that, for example, the respective axis 20 runs in the direction of longitudinal extent of the respective opening 16. The respective axis 20 coincides with a passage direction along which the mixture can flow out of the combustion chamber through the respective opening 16 and thus flow into the prechamber 12. In addition, the respective torch resulting from the firing of the portion of the mixture in the pre-chamber 12 may flow through the respective opening 16 and thus flow from the pre-chamber 12 into the combustion chamber. In particular when the openings 16 are designed, for example, as or by cylindrical bores, the respective flow cross section Q of the respective bore, also referred to as cross section, can be characterized by its diameter. In particular, it can be seen from FIG. 3 that the openings 16 are configured rotationally asymmetrically about the axis A and are in particular arranged in this case, such that the openings are arranged distributed non-uniformly in particular about the axis A. The tumble-shaped flow is thus effected, for example, by the different flow cross sections Q and / or by a particularly different distribution of the openings 16 around the axis A and / or by the corresponding number of openings 16.The pre-chamber 12 may be divided into four quadrants by the plane E and a second plane E 2. In this case, the planes E and E 2 run perpendicular to one another, and the planes E and E 2 intersect in the axis A, which thus runs in both planes E and E 2. In addition, an electrode region EB can be seen in which the electrodes 18 and 19, in particular their free ends, are arranged in the pre-chamber 12. Preferably, the plane E2 is the aforementioned roll plane.The tumble flow has a flow center that is orthogonal to the major axis (axis A) of the pre-chamber 12. The flow center is a roller axis about which the tumble flow runs in the shape of a roller. According to FIG. 3, the roller axis, also referred to as tumble flow axis, is orthogonal to the plane E 2 and runs, for example, in the plane E. In other words, the tumble flow can be defined as a flow structure in which the flow in half H 2 flows from the bores in the direction of the electrode region EB, which is also referred to as upward flow, then flows through the electrode region EB and in the first half H 1 flows from the electrode region EB in the direction of the bores, which is referred to as downward flow. As a result, the tumble flow is a structured flow shape which, however, is not rotationally symmetrical about the main axis, also referred to as the main axis of the prechamber.List of reference characters10 Pre-chamber spark plug 12 Pre-chamber 13 Double arrow 14 Contour 16 Opening 18 Electrode 19 Electrode 20 Axis A Axis B Viewing direction B 1 Opening B 2 Opening E Plane EB Electrode region E 2 Plane H 1 First half H 2 Second half M Center point Q Flow cross section

Claims

A pre-chamber spark plug (10) for a combustion chamber of an internal combustion engine, having a pre-chamber (12) which has a plurality of openings (16, B1, B2) and which can be fluidically connected to the combustion chamber via the openings (16, B1, B2), via which a fuel-air mixture can be introduced from the combustion chamber into the pre-chamber (12), wherein the respective opening (16, B1, B2) has a respective flow cross section (Q) through which the fuel-air mixture can flow, wherein, with respect to an imaginary plane (E) running along an imaginary axis (A) and dividing the pre-chamber (12) into two identically sized halves (H1, H2), the sum of the flow cross sections (Q) of the flow cross sections (Q) in a first of the halves (H1, H2), H2) openings (B1) arranged in the second half (H2) are larger than the sum of the flow cross sections (Q) of the openings (B2) arranged in the second half (H2), and wherein the openings (16) are configured rotationally asymmetrical about the axis (A), characterized in that the flow cross sections of at least two of the openings (16) differ from one another with regard to their shape.Pre-chamber spark plug (10) according to Claim 1, characterized in that the axis (20) runs in the direction of longitudinal extent (13) of the pre-chamber (12).Pre-chamber spark plug (10) according to Claim 1 or 2, characterized in that the pre-chamber (12) is designed to be rotationally symmetrical with respect to the axis (A).Pre-chamber spark plug (10) according to one of the preceding claims, characterized in that the flow cross sections (Q) of the openings (B1) arranged in the first half (H1) are larger than the flow cross sections (Q) of the openings (B2) arranged in the second half (H2).Pre-chamber spark plug (10) according to one of the preceding claims, characterized in that a number of the openings (B1) arranged in the first half (H1) is greater than a number of the openings (B2) arranged in the second half (H2).Pre-chamber spark plug (10) according to one of the preceding claims, characterized in that the openings (16, B1, B2) are circular, such that the openings (16, B1, B2) have a respective diameter, wherein the diameters of the openings (B1) arranged in the first half (H1) are greater than the diameters of the openings (B2) arranged in the second half (H2).Pre-chamber spark plug (10) according to one of the preceding claims, characterized in that the mean value of the flow cross sections (Q) of the openings (B1) arranged in the first half (H1) is greater than the mean value of the flow cross sections (Q) of the openings (B2) arranged in the second half (H2).Internal combustion engine for a motor vehicle, having at least one combustion chamber, and having a pre-chamber spark plug (10) which is assigned to the combustion chamber and has a pre-chamber (12) which has a plurality of openings (16, B1, B2) and is fluidically connected to the combustion chamber via the openings (16, B1, B2), via which a fuel-air mixture can be introduced from the combustion chamber into the pre-chamber (12), wherein the respective opening (16, B1, B2) has a respective flow cross section (Q) through which the fuel-air mixture can flow, wherein, with respect to an imaginary plane (E) which runs along an imaginary axis (A) and divides the pre-chamber (12) into two identically sized halves (H1, H2), the sum of the flow cross sections (Q) of the flow cross sections (Q) in a first of the halves (H1, H2), H2) openings (B1) arranged in the second half (H2) are larger than the sum of the flow cross sections (Q) of the openings (B2) arranged in the second half (H2), and wherein the openings (16) are configured rotationally asymmetrical about the axis (A), characterized in that the flow cross sections of at least two of the openings (16) differ from one another with regard to their shape.Internal combustion engine according to Claim 8, characterized in that the internal combustion engine is designed as a reciprocating piston engine.Motor vehicle, having an internal combustion engine according to Claim 8 or 9.

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