Pre-chamber unit

Abstract

The invention relates to a prechamber unit (1) for an internal combustion engine, comprising a prechamber body (2) forming a prechamber (3) and a nozzle cap (4) which is designed to open into a combustion chamber (5) of the internal combustion engine. The pre-chamber (3) is fluidically connected by a central connecting channel (9) and by at least one first nozzle channel (7) having a first orifice (10) in the nozzle cap (4) and by at least one second nozzle channel (8) having a second orifice (11) in the nozzle cap (4), the nozzle channels (7, 8) branching off from the connecting channel (9), the precombustion chamber unit (1) has a longitudinal axis (9a) and is arranged on different sides of a high plane (s) of the precombustion chamber unit (1) extending through the longitudinal axis (9a) of the connecting channel (9), and the spark plug (13) opens into the precombustion chamber (3). In order to achieve a stable ignition in the pre-chamber (3) and a rapid flame propagation into the combustion chamber (5), a first nozzle cap angle (oi) of the first orifice (10) and a second nozzle cap angle (02) of the second orifice (11) and / or a first orifice surface angle ([beta] i) of the first orifice (10) and a second orifice surface angle ([beta] z) of the second orifice (11) are designed differently, the nozzle cap (4) is asymmetrically shaped with respect to the high plane (s).

Description

[0001] This invention relates to a pre-combustion chamber unit for an internal combustion engine, comprising a pre-combustion chamber body forming a pre-combustion chamber, the pre-combustion chamber body having a nozzle cap configured to lead to a combustion chamber of the internal combustion engine, wherein the pre-combustion chamber is flowably connected via a central connecting channel and at least one first nozzle channel having a first orifice in the nozzle cap and at least one second nozzle channel having a second orifice in the nozzle cap, wherein the nozzle channels branch from the connecting channel and are arranged on different sides of a high plane extending through the longitudinal axis of the connecting channel of the pre-combustion chamber unit, wherein a spark plug leads to the pre-combustion chamber. Furthermore, this invention relates to a method of manufacturing such a pre-combustion chamber unit and an internal combustion engine having such a pre-combustion chamber unit.

[0002] A pre-combustion chamber unit for an internal combustion engine is known from EP 3 431 745 A1. The pre-combustion chamber of the pre-combustion chamber unit is connected via a central connecting hole and a nozzle channel having an orifice in a symmetrically formed nozzle cap, originating from the connecting hole.

[0003] DE 2017 009 235A1 and DE 2017 009 228A1 each disclose a pre-combustion chamber spark plug with an inlet opening having different inclinations. The inclination of the inlet opening relative to the axis of the pre-combustion chamber significantly affects the flow to the spark plug.

[0004] US2018 / 0230895 A1 discloses a pre-combustion chamber spark plug in which the inclination of the connection opening is designed to allow flow to more easily enter on the intake side.

[0005] US 4,646,695 A discloses a pre-combustion chamber spark plug with its inlet channel specially shaped to achieve swirl.

[0006] EP 3 536 923 A1 discloses a pre-combustion chamber leading to the main combustion chamber of an internal combustion engine, the pre-combustion chamber being formed by a pre-combustion chamber body. A spark plug is inserted into the pre-combustion chamber. The pre-combustion chamber body has a nozzle cap. The pre-combustion chamber is connected to orifices in the nozzle cap via a central connecting channel and nozzle channels. In all embodiments of EP 3 536 923 A1, a nozzle cap with a rotationally symmetrical external profile is shown. To advantageously influence the mid-flame torch (Brennfackel) entering the main combustion chamber, the distances between the pre-combustion chamber axis and the orifices of at least two nozzle channels are set to different sizes.

[0007] The combustion system of an internal combustion engine is typically designed and configured in terms of mixture, flow rate, turbulence, and exhaust gas recirculation to ensure that optimal conditions dominate at the spark plug, thereby guaranteeing a stable ignition spark and rapid early flame propagation. In the case of a pre-combustion chamber with a spark plug, the construction of the pre-combustion chamber, the flow connection (fluid communication) between the main combustion chamber and the pre-combustion chamber, and the manner in which the flow enters the pre-combustion chamber are crucial for achieving a stable ignition spark and rapid early flame propagation.

[0008] The objective of this invention is to achieve stable ignition in the pre-combustion chamber and rapid flame propagation into the combustion chamber.

[0009] According to the present invention, this is achieved in the following way:

[0010] - The angle of the first nozzle cap at the first orifice and the angle of the second nozzle cap at the second orifice, and / or

[0011] - The first orifice surface angle of the first orifice and the second orifice surface angle of the second orifice are constructed differently, wherein,

[0012] The first nozzle cap angle is defined as the angle between the longitudinal axis of the connecting channel and the tangent on the surface of the first nozzle cap adjacent to (closely adjacent to) the first orifice. Preferably, the surface of the first nozzle cap is adjacent to (closely adjacent to) the first orifice at a first distance of 1.5 times the diameter of the first nozzle channel from the first central axis of the first nozzle channel, and particularly preferably in the direction toward the end of the nozzle cap. The second nozzle cap angle is defined as the angle between the longitudinal axis of the connecting channel and the tangent on the surface of the second nozzle cap adjacent to (closely adjacent to) the second orifice. Preferably, the surface of the second nozzle cap is adjacent to (closely adjacent to) the second orifice at a second distance of 1.5 times the diameter of the second nozzle channel from the second central axis of the second nozzle channel, and particularly preferably in the direction toward the end of the nozzle cap.

[0013] The first orifice surface angle is defined as the angle between the longitudinal axis of the connecting channel and the first orifice surface or the tangent at the first orifice surface, and the second orifice surface angle is defined as the angle between the longitudinal axis of the connecting channel and the second orifice surface or the tangent at the second orifice surface.

[0014] The nozzle cap is asymmetrically shaped relative to the high plane.

[0015] Unlike EP 3 536 923 A1, in the pre-combustion chamber unit according to the invention, the nozzle cap has an asymmetrically shaped external profile.

[0016] In a simple embodiment of the invention, the nozzle cap surface of at least one orifice adjacent to (connected to) the nozzle channel is processed by material removal or material addition.

[0017] One embodiment of the invention specifies that the nozzle cap is asymmetrically formed by a process of material removal or material addition.

[0018] Particularly advantageous is that the first nozzle cap angle is greater than the second nozzle cap angle, wherein, preferably, the first nozzle cap angle is at least 10° greater than the second nozzle cap angle, and particularly preferably at least 20° greater. The first nozzle cap angle may be at least about 30°, preferably at least about 40°, and / or the second nozzle cap angle may be less than about 45°, preferably a maximum of 30°.

[0019] According to one embodiment of the invention, it may be alternatively or additionally specified that the first orifice surface angle is greater than the second orifice surface angle, wherein preferably the first orifice surface angle is at least 10° greater than the second orifice surface angle, particularly preferably at least 20° greater. Advantageously, the first orifice surface angle is at least about 30°, preferably at least about 40°, and the second orifice surface angle is less than about 45°, preferably at most 30°.

[0020] Different angles result in asymmetrical inflow into the pre-combustion chamber.

[0021] By varying the nozzle cap angle and / or the orifice surface angle, flow separation occurs on the side of the second nozzle channel facing the nozzle cap end in the case of inflow entering the first nozzle channel, resulting in flow throttling.

[0022] By using a larger first nozzle cap angle or a larger first orifice surface angle in the region of the first orifice, a throttling effect is achieved within the first nozzle channel as the gas inflow reaches the first nozzle channel from the combustion chamber, thereby reducing the flow rate. Conversely, a smaller nozzle cap angle or a smaller orifice surface angle in the region of the second orifice allows for unthrottled flow through the second nozzle channel. Due to the uneven inflow from the first and second nozzle channels into the connecting channel, asymmetrical flow is generated on the side of the high plane facing the second nozzle channel. This asymmetrical flow continues into the pre-combustion chamber. Therefore, an asymmetrical flow pattern is formed upon entering the pre-combustion chamber, where tumble is created. The tumble flow passes from the first nozzle channel side through the top wall of the pre-combustion chamber to the second nozzle channel side.

[0023] In this way, tumble flow is induced in the pre-combustion chamber within at least one operating range around a rotation axis that is parallel to, and preferably located within, the high plane.

[0024] Experiments have shown that, in the case of a pre-combustion chamber with a spark plug, the shape of the pre-combustion chamber, the flow connection between the main combustion chamber and the pre-combustion chamber, and the manner of flow entering the pre-combustion chamber are crucial for achieving a stable ignition spark and rapid early flame propagation. It has been demonstrated that optimal results can be obtained if tumble is generated in the pre-combustion chamber, particularly during the compression stroke prior to ignition, through asymmetric inflow into the pre-combustion chamber. Preferably, the asymmetric inflow is generated by manufacturing or processing at least one first nozzle cap surface adjacent to (closely adjacent to) at least one first orifice of the nozzle channel through material removal or material addition. This generates stable flow and sufficient turbulence at the spark plug and throughout the pre-combustion chamber, as well as the formation of a combustible mixture.

[0025] In one embodiment of the invention, a first nozzle channel and a connecting channel are defined to extend a first nozzle channel angle, and a second nozzle channel and a connecting channel are defined to extend a second nozzle channel angle. Preferably, the first nozzle channel angle is equal to the second nozzle channel angle, and particularly 100° to 140°, especially preferably 110° to 120°.

[0026] At least the surface of the first nozzle cap can be designed to be flat in the region of the first orifice. This enables simple material removal processes, such as cutting.

[0027] The pre-combustion chamber can be configured as a passive pre-combustion chamber, which has a spark plug but no injection device leading to it, or as an active pre-combustion chamber, which has at least one spark plug and at least one fuel injection device leading to it.

[0028] In one embodiment of the invention having an active pre-combustion chamber, the injection device is positioned on the side of the high plane opposite to the spark plug, leading into the pre-combustion chamber. Here, the spark plug and the first nozzle passage may be arranged on the same side of the high plane. In an alternative embodiment, the spark plug and the second nozzle passage are arranged on the same side of the high plane.

[0029] In embodiments with an active pre-combustion chamber, if the pre-combustion chamber has a generally mushroom-shaped shape, it is beneficial for stable ignition and rapid flame propagation. The pre-combustion chamber has a generally spherical, ellipsoidal, or disc-shaped central space following the connecting channel, and a spherical, ellipsoidal, dome-shaped, or disc-shaped top wall space between the central space and the top wall of the pre-combustion chamber. Preferably, the volume of the top wall space is larger than the volume of the central space. Particularly advantageously, the maximum diameter of the top wall space is approximately 1.5 to 2.5 times, for example, twice, the maximum diameter of the central space.

[0030] In one embodiment of the invention, the spark plug is specified to have a ground electrode and a center electrode, wherein the ground electrode is arranged transversely to the tumble flow in the pre-combustion chamber. Alternatively, the ground electrode may be specified to be designed and configured parallel to the tumble flow in the pre-combustion chamber.

[0031] For example, a pre-combustion chamber unit with an active pre-combustion chamber is suitable for spark-ignition internal combustion engines in which at least one intake passage is arranged on the intake side and at least one exhaust passage is arranged on the exhaust side, opposite to the intake side, relative to the engine height plane supported by at least two cylinder axes, wherein the spark plug is arranged on the exhaust side. Preferably, the height plane of the pre-combustion chamber coincides with the engine height plane.

[0032] The method with an active pre-combustion chamber according to the invention specifies that, during at least one compression stroke, tumble is generated in the pre-combustion chamber by an asymmetric inflow into the pre-combustion chamber, wherein the asymmetric inflow is preferably generated by manufacturing or processing, by means of material removal or material addition, at least one nozzle cap surface adjacent to at least one orifice of the nozzle channel.

[0033] According to the present invention, the pre-combustion chamber unit is manufactured by means of a method in which at least one nozzle cap surface adjacent to (immediately adjacent to) at least one orifice of the nozzle channel is processed by means of material removal or material addition.

[0034] Material removal processing is understood here as machining, especially cutting processes such as milling, turning, planing, grinding, honing, or thermal removal processes such as electrical discharge machining (EDM) or electrochemical removal processes. Material addition processing is understood, for example, as additive manufacturing methods.

[0035] The invention will now be explained in more detail with reference to the non-limiting embodiments shown in the accompanying drawings. Wherein:

[0036] Figure 1 This is a longitudinal cross-sectional view of the pre-combustion chamber unit according to the invention in a first embodiment variant;

[0037] Figure 2 for Figure 1 Details II;

[0038] Figure 3 For the pre-combustion chamber unit according to the invention, in a second embodiment variant, similar to Figure 2 Detailed view;

[0039] Figure 4 For the pre-combustion chamber unit according to the invention, in a third embodiment variant, similar to Figure 2 Detailed view;

[0040] Figure 5For the pre-combustion chamber unit according to the invention, similar in a fourth embodiment variant Figure 2 Detailed view;

[0041] Figure 6 For the pre-combustion chamber unit according to the invention, similar in a fifth embodiment variant Figure 2 Detailed view;

[0042] Figure 7 For from Figure 1 The pre-combustion chamber unit with the drawn flow path;

[0043] Figure 8 A longitudinal cross-sectional view of the pre-combustion chamber unit according to the invention in a sixth embodiment, showing the flow path; and Figure 9 This is a longitudinal cross-sectional view of the pre-combustion chamber unit according to the invention in a seventh embodiment variant, showing the flow path.

[0044] In the accompanying drawings, the same parts are indicated by the same reference numerals.

[0045] These figures illustrate a pre-combustion chamber unit 1 for a spark-ignition internal combustion engine having one or more cylinders, in an installed state. The pre-combustion chamber unit 1 has a pre-combustion chamber body 2, which, for example, forms an active pre-combustion chamber 3. The pre-combustion chamber unit 1 is fastened to the cylinder head ZK of the internal combustion engine and enters the combustion chamber 5 of the internal combustion engine cylinder at the lower first end 1a of the pre-combustion chamber unit 1 via a nozzle cap 4. The nozzle cap 4, extending tapered toward the nozzle cap end 6, has an even or odd number of nozzle channels 7, 8 formed by drilling.

[0046] The pre-combustion chamber 3 is fluidly connected via a central connecting channel 9 and at least one first nozzle channel 7 having a first orifice 10 in the nozzle cap 4 and at least one second nozzle channel 8 having a second orifice 11 in the nozzle cap 4. The first nozzle channel 7 and the second nozzle channel 8 branch off from the connecting channel 9 and are arranged on different sides of the high plane ε extending through the longitudinal axis 9a of the connecting channel 9 of the pre-combustion chamber unit 1. In the region of the pre-combustion chamber top wall 12, the spark plug 13 enters the pre-combustion chamber 3 on one side of the high plane ε, which is located at the upper second end 1b of the pre-combustion chamber unit 1 facing away from the nozzle cap 4. Reference numeral 13b indicates the central electrode arranged in the region of the spark plug's longitudinal axis 13a, and reference numeral 13c indicates the hook-shaped ground electrode.

[0047] For example, by removing material from the nozzle cap surfaces 14 and 15 of the orifices 10 and 11 of the adjacent (closely adjacent) transmission channels 7 and 8, optimal conditions in the pre-combustion chamber 3 can be ensured, thereby guaranteeing a stable ignition spark and rapid early flame propagation.

[0048] The type of processing depends on the shape of the pre-combustion chamber 3 and the components it contains, such as the spark plug 13 and the fuel injection device 16. The type of flow required depends on the injection strategy.

[0049] The machining of nozzle cap surfaces 14 and 15 can be used to adjust the flow rate through each nozzle channel 7 and 8, for example, by throttling the flow rate through the machining to generate a stronger flow S on one side of the pre-combustion chamber 3, thereby achieving a defined flow pattern, such as tumble flow S, in the pre-combustion chamber 3. The rotation direction and center position of the tumble flow W can also be controlled. The intensity of the flow is indicated by arrow S in the attached figures.

[0050] The intensity of the throttling depends on the intensity of the required charge motion and the desired position of the rotation axis M of the tumble flow W.

[0051] Figure 1 , Figure 7 , Figure 8 , Figure 9 The pre-combustion chamber unit 1, which has an active pre-combustion chamber 3, is shown. Here, in addition to the spark plug 13, a fuel injection device 16 also enters the pre-combustion chamber 3 in the region of the top wall 12 of the pre-combustion chamber, wherein the spark plug 13 and the fuel injection device 16 are located on different sides of the high plane ε. Reference numeral 16a indicates the longitudinal axis of the fuel injection device.

[0052] In the illustrated embodiment, the nozzle cap 4 is shaped asymmetrically with respect to the high plane ε by means of material removal or material addition, and thus has an asymmetrical profile. For example, the nozzle cap 4 may have a prismatic shape. The tip of the nozzle cap 4, i.e., the nozzle cap end 6, may be flat, which is indicated by reference numeral 17.

[0053] Facing the nozzle cap end 6, the first orifice 10 of the first nozzle channel 7 is tightly connected to the first nozzle cap surface 14, and facing the nozzle cap end 6, the second orifice 11 of the second nozzle channel 8 is tightly connected to the second nozzle cap surface 15. A first nozzle cap angle α1 is designed and constructed between the longitudinal axis 9a of the connecting channel 9 and the first nozzle cap surface 14, and a second nozzle cap angle α2 is designed and constructed between the longitudinal axis 9a of the connecting channel 9 and the second nozzle cap surface 15, wherein the second nozzle cap angle α2 is smaller than the first nozzle cap angle α1.

[0054] The first nozzle cap angle α1 is defined as the angle between the longitudinal axis 9a of the connecting channel 9 and the first nozzle cap surface 14 adjacent to (closely adjacent to) the first orifice 10, or the tangent at the first nozzle cap surface 14, which, for example, is adjacent to the first orifice 10 within a first distance a1 corresponding to 1.5 times the diameter d1 of the first nozzle channel 7, from the first central axis 7a of the first nozzle channel 7. The first nozzle cap surface 14 extends from the first nozzle channel 7, for example, toward the nozzle cap end 6.

[0055] The second nozzle cap angle α2 is defined as the angle between the longitudinal axis 9a of the connecting channel 9 and the second nozzle cap surface 15 adjacent to (closely adjacent to) the second orifice 10, or the tangent at the second nozzle cap surface 15. The second nozzle cap surface 15 is adjacent to the second orifice 10, for example, within a second distance a2 corresponding to 1.5 times the diameter d2 of the second nozzle channel 8 from the second central axis 8a of the second nozzle channel 8. The second nozzle cap surface 15 extends from the second nozzle channel 8, for example, toward the nozzle cap end 6.

[0056] The first nozzle cap angle α1 is particularly larger than the second nozzle cap angle α2 by at least 10°, and advantageously by at least 20°.

[0057] For example, the first nozzle cap angle α1 is at least about 30°, and particularly at least about 40°. For example, the second nozzle cap angle α2 is less than about 45°, and preferably at most 30°.

[0058] Alternatively or additionally, apart from the difference between the first nozzle cap angle α1 and the second nozzle cap angle α2, it may be specified that the first orifice surface angle β1 of the first orifice 10 and the second orifice surface angle β2 of the second orifice 11 are different.

[0059] The first orifice surface angle β1 is defined as the angle between the longitudinal axis 9a of the connecting channel 9 and the first orifice surface 10a of the first orifice 10, or between the first orifice surface 10a and the tangent at the first orifice surface 10a. The second orifice surface angle β2 is defined as the angle between the longitudinal axis 9a of the connecting channel 9 and the second orifice surface 11a of the second orifice 11, or between the second orifice surface 11a and the tangent at the second orifice surface 11a.

[0060] The first orifice surface 10a is formed by the intersection line of the first nozzle channel 7 and the first nozzle cap surface 14, and the second orifice surface 11a is formed by the intersection line of the second nozzle channel 8 and the second nozzle cap surface 15.

[0061] The first orifice surface angle β1 is greater than the second orifice surface angle β2, and the first orifice surface angle β1 is preferably at least 10° greater, and more preferably at least 20° greater.

[0062] In the illustrated embodiment, the second nozzle cap angle α2 and the second orifice surface angle β2 are configured to be equal. However, the second nozzle cap angle α2 and the second orifice surface angle β2 can also be configured to be different.

[0063] Figure 2 and Figure 5 An embodiment of the invention is shown, wherein the first nozzle cap angle α1 and the second orifice surface angle β1 are respectively configured to be equal. Figure 2In this configuration, the first orifice surface 10a and the nozzle cap surface 14 are only on one side of the orifice 10, i.e., on... Figure 2 Unlike the first nozzle channel 7, which is machined below the first nozzle channel 7, in Figure 5 In the process, the nozzle cap surface 14 is processed by material removal on both sides of the first nozzle channel 7.

[0064] Figure 3 An embodiment of the invention is shown in which the first orifice surface 10a is not machined, and only the nozzle cap surface 14 below the orifice 10 is machined, that is, only on the side of the first nozzle channel 7 facing the nozzle cap end 6 is machined.

[0065] exist Figure 4 and Figure 6 In the illustrated embodiment, both the first nozzle cap surface 14 and the first orifice surface 10a are machined, wherein the first nozzle cap angle α1 and the first orifice surface angle β1 are constructed differently, thus forming a step between the first orifice surface 10a and the first nozzle cap surface 14. Figure 4 In the process, the first orifice surface angle β1 and the second orifice surface angle β2 are configured to be equal, while... Figure 6 The opposite of the middle is different.

[0066] The first central axis 7a of the first nozzle channel 7 and the longitudinal axis 9a of the connecting channel 9 form a first nozzle channel angle γ1, and the second central axis 8a of the second nozzle channel 8 and the longitudinal axis 9a of the connecting channel 9 form a second nozzle channel angle γ2. Here, the first nozzle channel angle γ1 and the second nozzle channel angle γ2 are configured to be equal. In this embodiment, the first nozzle channel 7 and the second nozzle channel 8 are configured symmetrically with respect to the high plane ε of the pre-combustion chamber unit 1. The first nozzle channel angle γ1 or the second nozzle channel angle γ2 can be between 100° and 140°, for example, 110° to 120°.

[0067] For example, the first nozzle cap surface 14 and / or the second nozzle cap surface 15 are manufactured by material removal, such as machining, and may be configured to be flat, for example. Alternatively or additionally, in addition to material removal, material addition is also possible.

[0068] The processing type depends in principle on the shape of the pre-combustion chamber 3 and the components contained therein, spark plug 13 and / or fuel injection device 16. The required flow type depends on the injection strategy and the type of pre-combustion chamber 3, i.e., a passive pre-combustion chamber 3 without injection into the pre-combustion chamber 3 or an active pre-combustion chamber 3 with injection.

[0069] In the illustrated embodiments, the pre-combustion chamber 3 excluding the connecting channel 9 has a generally mushroom-shaped shape, or the pre-combustion chamber 3 including the connecting channel 9 has a generally lantern-shaped shape. The actual pre-combustion chamber 3 here has a generally spherical, ellipsoidal, or disc-shaped central space 3a following the connecting channel 9, and a spherical, ellipsoidal, dome-shaped, or disc-shaped top wall space 3b between the central space 3a and the pre-combustion chamber top wall 12, wherein the volume of the top wall space 3b is larger than the volume of the central space 3a. The maximum diameter D2 of the top wall space 3b is approximately 1.5 to 2.5 times, for example, twice, the maximum diameter D1 of the central space 3a. The sidewall 3c of the pre-combustion chamber 3 is constructed substantially parallel to the longitudinal axis 9a at the transition from the central space 3a to the top wall space 3b, for example, constructed as a cylinder. At the transition between the sidewall 3c and the top wall space 3b, at least one flow separation edge 3d can be designed to be constructed for the flow S flowing in the direction toward the pre-combustion chamber top wall 12. Figure 1 ).

[0070] The machining of nozzle cap 6 and nozzle cap surfaces 14, 15 can be used to specifically design different flow rates through each nozzle channel 7, 8, especially on one side of the pre-combustion chamber 3, for example on the side of the first nozzle channel 7, to generate a stronger flow S and produce a defined flow pattern, such as tumble flow W. The position of the rotation axis M and the rotation direction of the tumble flow W can also be predetermined through machining.

[0071] By machining the nozzle cap surfaces 14 and 15 to form defined nozzle cap angles α1 and α2 and / or orifice surface angles β1 and β2, the second nozzle channel 8 achieves unobstructed flow at the maximum possible flow rate, and a throttling effect is formed in the first nozzle channel 7 through the first stagnation zone T1. This results in an asymmetric flow pattern with a second stagnation zone T2 in the connecting channel 9, so that the flow mainly enters the pre-combustion chamber 3 from the connecting channel 9 on the side of the second nozzle channel 8 (see...). Figures 2 to 6 ).

[0072] Figure 1 and Figure 7 One embodiment is shown, wherein the spark plug 13 is arranged on the same side as the second nozzle passage 8 relative to the high plane ε. The fuel injection device 16 is arranged on the same side as the first nozzle passage 7. The ground electrode 13c of the spark plug 13 is arranged transversely to the tumble flow W, i.e., approximately parallel to the high plane ε.

[0073] The nozzle cap 4 is machined to generate tumble flow around the hook-shaped ground electrode 13c of the spark plug 13 by throttling on the side of the second nozzle channel 8, wherein the tumble flow W rotates from the spark plug 13 toward the fuel injection device 16.

[0074] In contrast, Figure 8In the middle, the ground electrode 13c of spark plug 13 is relative to Figure 1 The implementation in the embodiment rotates 90° around the spark plug axis 13a, i.e., it is formed toward or parallel to the tumble flow W.

[0075] The nozzle cap 4 is machined to generate a strong flow toward the spark plug 13 by throttling on the same side of the pre-combustion chamber 3. Since the hook-shaped ground electrode 13c is an obstruction to the flow S, a tumble flow W is generated below the ground electrode 13c, which rotates from the spark plug 13 toward the fuel injection device 16.

[0076] Figure 9 A variant embodiment is shown in which the spark plug 13 is arranged on the same side as the first nozzle channel 7 relative to the high plane ε. The fuel injection device 16 is disposed on the same side as the second nozzle channel 8. The ground electrode 13c of the spark plug 13 is formed along or parallel to the tumble flow W. The nozzle cap 4 is machined to generate a strong flow S toward the fuel injection device 16 by throttling on the side of the second nozzle channel 8 in the pre-combustion chamber 3. Tumble flow W is generated between the fuel injection device 16 and the spark plug 13 in the pre-combustion chamber 3.

[0077] The processing also depends on the main flow in the combustion chamber 5 of the internal combustion engine. Here, as the amount of mixture forced into the nozzle channels 7 and 8 increases, the requirement for throttling effect also increases.

[0078] The pre-combustion chamber unit 1 according to the invention is suitable for a spark-ignition internal combustion engine, wherein at least one intake passage is arranged on the intake side, and at least one exhaust passage is arranged on the exhaust side, opposite to the intake side, relative to the engine height plane supported by at least two cylinder axes. Here, the spark plug 13 is preferably arranged on the exhaust side. The height plane ε of the pre-combustion chamber unit 1 can advantageously coincide with the engine height plane.

Claims

1. A pre-combustion chamber unit (1) for an internal combustion engine, the pre-combustion chamber unit (1) having a pre-combustion chamber body (2) forming a pre-combustion chamber (3), the pre-combustion chamber body (2) having a nozzle cap (4) configured to lead to a combustion chamber (5) of the internal combustion engine, wherein, The pre-combustion chamber (3) is fluidly connected via a central connecting channel (9) and at least one first nozzle channel (7) having a first orifice (10) in the nozzle cap (4) and at least one second nozzle channel (8) having a second orifice (11) in the nozzle cap (4), wherein the nozzle channels (7, 8) branch off from the connecting channel (9) and are located on different sides of the high plane (ε) of the longitudinal axis (9a) extending through the connecting channel (9) of the pre-combustion chamber unit (1), wherein a spark plug (13) is introduced into the pre-combustion chamber (3), characterized in that, - The first nozzle cap angle (α1) of the first orifice (10) and the second nozzle cap angle (α2) of the second orifice (11) and / or - The first orifice surface angle (β1) of the first orifice (10) and the second orifice surface angle (β2) of the second orifice (11) are constructed differently. Wherein, the first nozzle cap angle (α1) is defined as the angle between the longitudinal axis (9a) of the connecting channel (9) and the first nozzle cap surface (14) adjacent to the first orifice (10) or the tangent at the first nozzle cap surface (14). The first nozzle cap surface (14) is preferably located within a first distance (a1) of 1.5 times the diameter (d1) of the first nozzle channel (7) from the first central axis (7a) of the first nozzle channel (7), and particularly preferably adjacent to the first nozzle cap surface (14) of the first orifice (10) in the direction toward the nozzle cap end (6). Furthermore, the second nozzle cap angle (α2) is defined as the angle between the longitudinal axis (9a) of the connecting channel (9) and the second nozzle cap surface (15) adjacent to the second orifice (10) or the tangent at the second nozzle cap surface (15), wherein the second nozzle cap surface (15) is preferably located within a second distance (a2) from the second central axis (8a) of the second nozzle channel (8) equivalent to 1.5 times the diameter (d2) of the second nozzle channel (8), and particularly preferably adjacent to the second nozzle cap surface (15) of the second orifice (10) in the direction toward the nozzle cap end (6). The first orifice surface angle (β1) is defined as the angle between the longitudinal axis (9a) of the connecting channel (9) and the first orifice surface (10a) of the first orifice (10) or the tangent at the first orifice surface (10a) of the first orifice (10), and the second orifice surface angle (β2) is defined as the angle between the longitudinal axis (9a) of the connecting channel (9) and the second orifice surface (11a) of the second orifice (11) or the tangent at the second orifice surface (11a) of the second orifice (11). The nozzle cap (4) is asymmetrically shaped relative to the high plane (ε).

2. The pre-combustion chamber unit (1) according to claim 1, characterized in that, The first nozzle cap angle (α1) is greater than the second nozzle cap angle (α2), wherein, preferably, the first nozzle cap angle (α1) is at least 10° greater than the second nozzle cap angle (α2), and particularly preferably at least 20° greater.

3. The pre-combustion chamber unit (1) according to claim 1 or 2, characterized in that, The first nozzle cap angle (α1) is at least about 30°, preferably at least about 40°, and / or the second nozzle cap angle (α2) is less than about 45°, preferably at most 30°.

4. The pre-combustion chamber unit (1) according to any one of claims 1 to 3, characterized in that, The first orifice surface angle (β1) is greater than the second orifice surface angle (β2), wherein, preferably, the first orifice surface angle (β1) is at least 10° greater than the second orifice surface angle (β2), and particularly preferably at least 20° greater.

5. The pre-combustion chamber unit (1) according to claim 1 or 2, characterized in that, The first orifice surface angle (β1) is at least about 30°, preferably at least about 40°, and / or the second orifice surface angle (β2) is less than about 45°, preferably at most 30°.

6. The pre-combustion chamber unit (1) according to any one of claims 1 to 5, characterized in that, The first nozzle channel (7) and the connecting channel (9) extend to form a first nozzle channel angle (γ1), and the second nozzle channel (8) and the connecting channel (9) extend to form a second nozzle channel angle (γ2), wherein the first nozzle channel angle (γ1) is equal to the second nozzle channel angle (γ2), and preferably is 100° to 140°, particularly preferably 110° to 120°.

7. The pre-combustion chamber unit (1) according to any one of claims 1 to 6, characterized in that, At least the first nozzle cap surface (14) and / or the second nozzle cap surface (15) are designed to be flat.

8. The pre-combustion chamber unit (1) according to any one of claims 1 to 7, characterized in that, The spark plug (13) is inserted into the pre-combustion chamber (3) on one side of the high plane (ε).

9. The pre-combustion chamber unit (1) according to claim 8, characterized in that, On the side of the high plane (ε) opposite to the spark plug (13), the injection device (16) is introduced into the pre-combustion chamber (3) which is designed to be active.

10. The pre-combustion chamber unit (1) according to claim 8 or 9, characterized in that, The spark plug (13) and the first nozzle channel (7) are located on the same side of the high plane (ε).

11. The pre-combustion chamber unit (1) according to claim 8 or 9, characterized in that, The spark plug (13) and the second nozzle channel (8) are arranged on the same side of the high plane (ε).

12. The pre-combustion chamber unit (1) according to any one of claims 1 to 11, characterized in that, The spark plug (13) has a center electrode (13b) and a ground electrode (13c), wherein the ground electrode (13c) is arranged transversely to the tumble (W) in the pre-combustion chamber (3).

13. The pre-combustion chamber unit (1) according to any one of claims 1 to 11, characterized in that, The spark plug (13) has a center electrode (13b) and a ground electrode (13c), wherein the ground electrode (13c) is designed to be parallel to the tumble (W) in the pre-combustion chamber (3).

14. The pre-combustion chamber unit (1) according to any one of claims 1 to 13, characterized in that, The pre-combustion chamber (3) has a basic mushroom shape, wherein the pre-combustion chamber (3) has a basic spherical, ellipsoidal, or disc-shaped central space (3a) after the connecting channel (9), and a spherical, ellipsoidal, dome-shaped, or disc-shaped top wall space (3b) between the central space (3a) and the top wall (12) of the pre-combustion chamber, wherein preferably the volume of the top wall space (3b) is larger than the volume of the central space (3a).

15. The pre-combustion chamber unit (1) according to claim 14, characterized in that, The maximum diameter (D2) of the top wall space (3b) is about 1.5 to 2.5 times, in particular twice, the maximum diameter (D1) of the central space (3a).

16. The pre-combustion chamber unit (1) according to any one of claims 1 to 15, characterized in that, At least one nozzle cap surface (14, 15) of at least one orifice (10, 11) adjacent to the nozzle channel (7, 8) is manufactured by material removal or material addition.

17. The pre-combustion chamber unit (1) according to any one of claims 1 to 16, characterized in that, The nozzle cap (4) is manufactured asymmetrically relative to the high plane (ε) by material removal or material addition.

18. A method for operating an internal combustion engine having a pre-combustion chamber unit (1) according to any one of claims 1 to 17, characterized in that, During at least one compression stroke, a tumble (W) is generated in the pre-combustion chamber (3) by an asymmetric inflow into the pre-combustion chamber (3), wherein, preferably, the asymmetric inflow is generated by manufacturing or processing at least one nozzle cap surface (14, 15) of at least one orifice (10, 11) adjacent to the nozzle passages (7, 8) by material removal or material addition.

19. A spark-ignition internal combustion engine comprising a pre-combustion chamber unit according to any one of claims 1 to 18, wherein, At least one intake passage is provided on the intake side, and at least one exhaust passage is provided on the exhaust side opposite to the intake side relative to the engine high plane supported by at least two cylinder axes, characterized in that the spark plug (13) is provided on the exhaust side, wherein, preferably, the high plane (ε) of the pre-combustion chamber unit (1) coincides with the engine high plane.

Images