Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P23/00—Other ignition
  • F02P23/04—Other physical ignition means, e.g. using laser rays
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P13/00—Sparking plugs structurally combined with other parts of internal-combustion engines

Definitions

• the invention relates to a laser spark plug according to the preamble of claim 1.
• WO 2005/066488 A1 discloses a device for igniting an internal combustion engine, which comprises an ignition laser.
• the ignition laser has at its combustion chamber end a combustion chamber window which is transmissive to the laser pulses emitted by the ignition laser.
• the combustion chamber window must withstand the high pressures and temperatures prevailing in the combustion chamber and seal the interior of the ignition laser against the combustion chamber. In this case, in particular at the combustion chamber facing surface of the combustion chamber window high
• the present invention has the advantage of making the operation of the laser spark plug more reliable.
• measures are taken according to the invention to reduce deposits on the combustion chamber window.
• the invention provides that a laser spark plug for an internal combustion engine at least one means for guiding, shaping and / or for generating laser radiation and a combustion chamber window and a housing, wherein the housing on the side opposite the center of the combustion chamber window, in particular on a
• a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber.
• the diaphragm affects the conditions to which the combustion chamber window is exposed, so that the formation of deposits on the combustion chamber window is reduced and the
• the means for guiding, shaping and / or for generating laser radiation may be, on the one hand, a solid-state laser, for example a passively Q-switched solid state laser, which is monolithic, for example.
• Devices for the optical excitation of the solid-state laser, in particular semiconductor lasers, may be included in the laser spark plug. Alternatively, it is possible to use optical devices
• Laser spark plug may occur. Also spaced from the laser spark plug arrangement of one or more solid-state laser, in particular Q-switched or
• Laser spark plug itself no laser-active element, but only jet-guiding and / or beam-shaping means, in particular lenses and / or mirrors comprises.
• the housing is also particularly the task of mechanically fixing at least one means for guiding, shaping and / or for generating laser radiation and the combustion chamber window.
• the combustion chamber window is a transparent, consisting of at least one permanently heat and radiation resistant solid, such as a glass or crystal, for example sapphire, existing component. These are in particular the in
• the invention provides that the housing its means of guiding, shaping and / or generating laser radiation
• Combustion chamber facing side of the combustion chamber window having a diaphragm.
• Combustor window is thus arranged in particular between the means for guiding, shaping and / or for the generation of laser radiation and the diaphragm.
• the diaphragm forms a combustion chamber-side end portion of the housing.
• the panel is designed as a separate component and attached to a further part of the housing, for example, welded or screwed.
• further components of the laser spark plug such as purged and / or unsprayed prechambers, are arranged on the combustion chamber side of the diaphragm.
• the diaphragm is in particular a passage, in particular exactly one passage, exhibiting structure.
• the combustion chamber facing the side of the combustion chamber window communicates with the combustion chamber and / or with one of the diaphragm upstream antechamber of the laser spark plug, in particular exclusively, through the one passage of the diaphragm.
• the passage is bounded radially to the direction of radiation by the inner contour of the diaphragm.
• the passage is moreover provided for the passage of the laser radiation guided through the means, shaped and / or generated into a combustion chamber of an internal combustion engine, into an antechamber of the combustion chamber and / or into an antechamber of the laser spark plug arranged upstream of the diaphragm.
• the invention is based on the idea that by the provision of a diaphragm, or by a suitable design of such a diaphragm, a protection of the combustion chamber window is possible, in particular protection of the combustion chamber window prevailing in a combustion chamber conditions, especially at high temperatures, high flow velocities and Media like oil ash etc.
• the inventively provided aperture on the one hand reduces the amount of precipitating on the combustion chamber window pollution in the form of particles, oil pockets, etc.
• the impulse with which, for example, the particles impinge on the surface of the combustion chamber window is reduced. Both effects ensure that deposits on the combustion chamber window are significantly reduced and that the few deposits adhere less firmly to the combustion chamber window.
• the Laser ignition device according to the invention more reliable.
• Another effect of the shutter is that the temperature of the combustion chamber window is lowered. Due to the reduced temperature, a chemical reaction of the deposits or a chemical reaction of the combustion chamber window with the deposits, as it were a burn-in of the deposits and thus a permanent damage to the combustion chamber window, avoided. Remaining deposits thus adhere less firmly to the combustion chamber window and can be easily cleaned.
• a reduction in the pressure applied to the combustion chamber window, or the pressure change rates taking place there, can also be achieved by means of a
• Shutter invention be effected, which can also result in reliability increases.
• the length of the aperture is to be understood as meaning, in particular, the length of the passage of the aperture in the jet direction.
• a longitudinal axis of the laser spark plug or a direction perpendicular to the surface of the combustion chamber window facing the combustion chamber can also be used.
• the length of the passage is further measured between the opening facing the combustion chamber (also: outlet opening) and the opening facing away from the combustion chamber (also: inlet opening) of the diaphragm.
• irregularly shaped openings are to be used in particular to determine whether there is predominantly lateral shielding of the section which is to be considered as passage. Avoiding deposits on the
• Combustion chamber window in particular by flow deflection and by reducing the temperature of the combustion chamber window, takes place at orifices whose length is 4 mm or more. Increasingly good results are achieved with screens whose minimum length is 6mm, 8mm, 10mm or 12mm. The upper limit for the length of the aperture is 25mm, 20mm or 15mm. Even longer apertures could excessively increase the length and thus the space required for the installation of a laser spark plug.
• the choice according to the invention of the length of the diaphragm in particular the provision of one of the mentioned minimum lengths and / or upper limits, is suitable for all
• the targeted choice of the length of the diaphragm is provided in a laser spark plug for an internal combustion engine, comprising at least one means for guiding, shaping and / or generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the side opposite the center of the combustion chamber window, in particular at a combustion chamber-side end of the housing, a diaphragm for passage the guided by the means, shaped and / or generated laser radiation in a combustion chamber, the diaphragm, in particular a material of the diaphragm targeted to be selected so that it has a high thermal conductivity.
• the material of the panel should also have a high wear resistance, in particular heat resistance, as can be achieved, for example, by high-alloy steels.
• the material of the entire aperture can be uniform with that of the entire housing and have a high thermal conductivity. But it is also possible to form only the entire diaphragm of a material having a high thermal conductivity, while other components of the housing another, especially lower,
• brass and nickel and copper and alloys of brass and nickel as well as copper alloys come into consideration, for internal, as it were designed as "souls", parts of the aperture especially copper.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the means
• the cooling channel is provided in particular for the flow through with a cooling medium, for example a cooling liquid.
• a cooling medium for example a cooling liquid.
• the provision of several cooling channels and / or a cooling channel diameter of 1 mm 2 or more and / or 5 mm 2 or less is preferable.
• Such a cooling channel is in itself already suitable for reducing the temperature of the combustion chamber window.
• the heat from the aperture can be particularly well supplied to the cooling channel and thus dissipate from the aperture.
• Both the specific choice of the length of the aperture, as well as the specific choice of material and / or the provision of cooling channels are suitable alone, but especially in cooperation, to effect the reduction of the temperature of the combustion chamber window, in particular combinations of a specified, the length the feature concerned with a given, the heat conduction of the panel relevant feature in terms of the prevention of deposits on the combustion chamber window and thus in terms of the reliability of the laser spark plug are advantageous.
• the reduction in the temperature of sealing points arranged in the region of the combustion chamber window also improves the reliability of the laser spark plug.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or Generation of laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the opposite side of the center of the combustion chamber window, in particular at a combustion chamber end of the housing, a diaphragm for the passage of the guided, guided and / or generated laser radiation by the means in a Has combustion chamber, the combustion chamber window on the combustion chamber side upstream of a communicating with the interior of the aperture gap is provided, the height is deliberately selected low.
• a gap is to be understood as meaning, in particular, a spatial region which is bounded axially on both sides, in particular on one side by the combustion chamber window and the diaphragm, and radially on the outside, in particular by the housing, and communicates with the interior of the diaphragm via its radial inner side.
• the gap is thus formed between the diaphragm and the combustion chamber window. Under the height of the gap, in particular, the distance between the gap axially limiting surfaces to understand. For irregular geometries, it is important to consider whether an axial
• this embodiment of the invention is based on the finding that the temperature of a hot plug penetrating into the gap according to the invention is hot
• Laser radiation with intensities, as they usually occur in the region of the combustion chamber window, can be reliably ablated, so that in sum from the soot formation occurring in the gap only a moderate impairment of the transparency of the
• the total resulting avoidance of deposits on the combustion chamber window occurs for gap heights which are not more than 1 mm, not more than 0.5 mm, not more than 0.3 mm or not more than 0.1 mm.
• the lower limit for the height of the gap is 0.05 mm and 0.08 mm. In too flat columns, not enough soot can be formed. It is also advantageous to directly advance the gap to the combustion chamber window and / or to choose the base area of the gap to be ring-shaped or sickle-shaped.
• the surface area of the base area of the gap (hereinafter referred to as "gap cross-section") is preferably chosen to be sufficiently large so that the amount of gas entering is sufficient for adequate soot formation one
• Has inlet cross-section of the aperture and the gap cross-section is at least 10% of the inlet cross section, at least 30% of the inlet cross section or at least 50% of the inlet cross section or at least twice as large as the inlet cross section or at least four times as large as the inlet cross section.
• As upper limits are gap cross sections into consideration, which are 25 times as large as the inlet cross section, in particular 10 times as large as the inlet cross section, since the laser spark plug would otherwise be excessively large.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the opposite side of the center of the combustion chamber window, in particular on a
• a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber, the combustion chamber window upstream of the combustion chamber side with the interior of the diaphragm
• communicating gap is provided to selectively select the height of the gap so that soot formation is completely or at least largely avoided.
• the height of the gap it is advantageous to choose the height of the gap not less than 0.3 mm, in particular not less than 1 mm. It is particularly safe to avoid soot formation if the gap is even higher, for example at least 2 mm or at least 3 mm high.
• the provision of a small gap cross-section compared to the inlet cross-section of the aperture is also favorable; in particular, it is advantageous that the gap cross-section is at most 100%, in particular at most 40%, preferably at most 20% of the inlet cross-section of the aperture.
• the combustion chamber-side end of the housing a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber, the aperture on its side facing away from the combustion chamber window side a small
• Opening cross-section also: "outlet cross-section" has.
• the outlet cross section of the diaphragm is in particular the open combustion chamber side
• the smallness of the outlet cross-section of the diaphragm results in the advantageous effect that the combustion chamber window shields the conditions prevailing in the combustion chamber, in particular from high temperature, from rapid pressure fluctuations, high flow velocity and / or particles of oil pockets, soot and
• the specific choice of the length of the aperture, the targeted choice of material and / or the provision of cooling channels are each already alone or in combinations with each other already suitable to reduce the temperature of the combustion chamber window, so that a "burning" of pollution on the combustion chamber window is reduced and thus the
• a gap upstream of the combustion chamber window on the combustion chamber side By providing a gap upstream of the combustion chamber window on the combustion chamber side, a similar effect can be achieved in the manner described above, and if these measures are combined with the provision of a small outlet cross section of the diaphragm, the overall effect is that on the one hand On the other hand, the combustion chamber window is also less resistant to contamination by these remaining particles, and the reliability of the laser spark plug can be significantly increased in this way.
• Advantageous embodiments additionally or alternatively to the specific choice of the length of the diaphragm and additionally or alternatively to the provision of a high
• a laser spark plug for an internal combustion engine comprises at least one means for guiding, shaping and / or generating laser radiation and a combustion chamber window and a housing , wherein the housing on the opposite side of the middle of
• Combustor window in particular at a combustion chamber end of the housing, an aperture, in particular a cylindrical aperture, for the passage of the guided, guided and / or generated by the means laser radiation in a combustion chamber, wherein the length of the aperture is L and the outlet cross-section of the aperture Q B A is where 1 ⁇ L / (4Q BA / 7t) / 2 ⁇ 10.
• the size (4Q BA / 7t) 1 represents the
• a small outlet cross-section of the diaphragm provided that in a laser spark plug for an internal combustion engine, comprising at least one means for guiding, shaping and / or for generating laser radiation, further comprising Brennraumten and a housing, wherein the housing on the opposite side of the center of the combustion chamber window, in particular on a
• the combustion chamber-side end of the housing a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber, the inner contour of the diaphragm in a region of both the combustion chamber
• an edge of the inner contour of the diaphragm is to be understood as meaning, in particular, a geometric object, in particular a line, against which different areas of the inner contour of the diaphragm meet at an angle different from zero.
• a region of the inner contour of the diaphragm which is spaced both from the end of the diaphragm facing the combustion chamber and from the end of the diaphragm facing away from the combustion chamber is to be understood as meaning a central region of the inner contour of the diaphragm, in particular an area which, with respect to the longitudinal extent the aperture is centered.
• a region is in the center of the longitudinal extent of the diaphragm, in particular when it is arranged between a front fifth and a rear fifth of the diaphragm, in particular between a front quarter and a rear quarter of the diaphragm, or is arranged in a central third of the diaphragm ,
• An inner contour which has an edge in a region is to be understood as meaning that at least parts of the edge are arranged in this region, wherein it is also possible for the edge to be arranged in but also outside this region.
• Flow in the aperture represents.
• turbulence of the gas flowing into the orifice or of the gas flowing in the orifice can occur.
• the disorder in particular as a result of turbulence, is the
• a plurality of edges are two or more edges, in particular more than two edges. Particularly effective is the arrangement of one edge or a plurality of edges, when it faces the combustion chamber solid at least along parts of the edge and / or the combustion chamber window unobstructed, ie without parts of the diaphragm between the parts of the edge and the parts of the
• Combustor windows are arranged.
• the edge is particularly suitable, a disturbance or a turbulence in the parts of the in the aperture
• a particularly advantageous arrangement of the edge or the plurality of edges is such that it comes to the formation of steps by the arrangement of the edge or by the arrangement of the plurality of edges and / or that the inner contour of the aperture at least partially in the direction of the combustion chamber facing end gradually tapered.
• at least two, in particular at least three, preferably at least four stages may be provided.
• at least one further stage, in particular a plurality of further stages can be provided, at which the panel tapers in the direction of its end facing away from the combustion chamber.
• a step of the inner contour is understood in particular to mean an arrangement of at least three partial surfaces of the inner contour, one of the partial surfaces being arranged in the longitudinal direction of the inner contour between the two other partial surfaces and the radial inclination of the one partial surface being related to the radial inclinations of all three partial surfaces extremal is.
• the partial surfaces may in particular have an annular shape, but other geometries are possible in principle.
• the steps are formed almost at right angles (88 ° -92 °), in particular at right angles, ie in particular, the two partial surfaces extend parallel to a longitudinal axis of the laser spark plug, while one partial surface is oriented perpendicular thereto.
• a plurality of such stages for example, more than three or more than seven may be provided.
• steps that consist of surfaces that always or partially at obtuse angles or always or partially at acute angles, but preferably not in angles more than 25 °, collide, are conceivable and advantageous in each case in different ways. Combinations of stages of the mentioned types are in principle possible in a diaphragm.
• Provision of at least one edge in an area, both from the Combustion chamber facing the end of the aperture as well as from the combustion chamber remote from the end of the aperture is spaced, each of which makes it possible to reduce the number of particles that impinge on the combustion chamber window. If both measures are combined with each other, the synergetic effect that results from the small one results
• Outlet cross-section of the aperture spatially concentrated flow in the aperture particularly targeted disturbing by suitable edges can swirl.
• exit cross-sections of 78 mm 2 or less, in particular 19 mm 2 or less, preferably 7 mm 2 or less, particularly preferably 2 mm 2 or less, these exit diameters are each advantageously advantageously provided with a step-shaped
• Inner contour of the aperture can be combined, in particular with a stepped inner contour of the aperture, which has a plurality of stages, in particular of
• Laser spark plug for an internal combustion engine comprising at least one guiding means, Forming and / or for generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the means
• a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber, the diaphragm having an end facing the combustion chamber and an end facing away from the combustion chamber, the inner contour of the diaphragm in a region which is spaced from both the combustion chamber facing the end of the aperture and the combustion chamber facing away from the end of the aperture, having an extreme cross-section.
• the inner contour of a diaphragm is in particular a cross-section to understand, with respect to its surface area and with respect to the
• Longitudinal direction of the laser spark plug represents a local maximum, that is, in particular, is reduced in both longitudinal directions, or represents a local minimum, that is, in particular, increases in both longitudinal directions.
• the extreme cross-section of the diaphragm in a region which is spaced both from the end of the diaphragm facing the combustion chamber and from the end of the diaphragm facing away from the combustion chamber can be expressed in particular in that there is a cross section of the diaphragm which is larger than the diaphragm Inlet cross-section of the aperture and is greater than the outlet cross-section of the aperture, or that there is a cross-section of the aperture, which is smaller than the inlet cross-section of the aperture and smaller than the outlet cross-section of the aperture.
• the cross-section is a cross-section that lies in a plane that is parallel to a plane in which the outlet cross-section of the diaphragm is located and / or lies in a plane that is parallel to a plane in which the inlet cross-section Aperture is and / or lies parallel to a plane in which the combustion chamber facing surface of the combustion chamber window is and / or oriented perpendicular to a longitudinal axis of the laser spark plug.
• the technical effect of the measure that the inner contour of the diaphragm in an area which is spaced from both the combustion chamber facing the end of the aperture and the combustion chamber facing away from the end of the aperture, has an extreme cross section, is that the area extremalen Cross-section represents a starting point for a disturbance of the influx of gases into the diaphragm or a disturbance of the flow in the diaphragm.
• the area extremalen Cross-section represents a starting point for a disturbance of the influx of gases into the diaphragm or a disturbance of the flow in the diaphragm.
• turbulence of the exhaust gas flowing into the diaphragm or the flow in the diaphragm can occur.
• Aperture has an inlet cross section at its end facing the combustion chamber and at its end facing the combustion chamber has an outlet cross section and that the extremal cross section either at least 10%, in particular at least 20%, preferably at least 30%, smaller than the inlet cross section and at least 10%, in particular at least 20%, preferably at least 30%, is smaller than the outlet cross section or at least 10%, in particular at least 20%, preferably at least 30%, greater than inlet cross section and at least 10%, in particular at least 20%, preferably at least 30%, greater than the outlet cross-section is.
• Inner contour of the diaphragm provides that the inner contour of the diaphragm has two sections, each having a frusto-conical shape, in particular in the form of a straight circular truncated cone, these two sections are preferably immediately adjacent, ie each with its larger or each with its smaller Face adjacent to each other and thus form as it were a double truncated cone. At the point where the truncated cones adjoin one another thus forms an edge which extends either along a constriction or along a bulge of the inner contour of the panel.
• Laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or for generating laser radiation, further comprising
• a diaphragm for the passage of the guided through the means, shaped and / or generated laser radiation in a combustion chamber, to deviate from a rotationally symmetrical shape of the inner contour of the diaphragm.
• bulge in particular a plurality of bulges, which are spaced in particular both from the combustion chamber facing the end of the diaphragm and from the combustion chamber remote from the end of the diaphragm are advantageous because the recess and / or the bulge a starting point for a disturbance Influence of exhaust gases in the aperture represent.
• turbulence of the gas flowing into the orifice may occur.
• the bulge and / or the recess is located in a region of the diaphragm which is spaced both from the end of the diaphragm facing the combustion chamber and from the end of the diaphragm facing away from the combustion chamber and which has an extreme cross-section.
• the provision of other inner contours of the diaphragm, in particular those which are optimized in terms of flow, for example, not sharp-edged, but rounded and / or completely or partially formed as a Laval nozzle is conceivable in principle.
• the life of the laser spark plug can be significantly increased in this way.
• the laser spark plug at least one focusing means for determining a beam shape of the laser beam passing through the aperture and the distance between the aperture and laser radiation does not exceed a maximum distance, at least along predominant parts of the inner contour of the diaphragm.
• the at least one focusing means may be a focusing optics, for example one or more lenses and / or one or more mirrors, in particular one or more mirrors each having a curved surface.
• the formation of the combustion chamber window and / or the formation of the means for guiding, shaping and / or for the generation of laser radiation as
• the focusing element is additionally or alternatively possible.
• the at least one focusing means is a beam shape through the aperture
• Operating parameter of the laser spark plug for example, a current or a temperature dependent, as the beam shape determined by the focusing means, to understand the beam shape provided by the laser spark plug when the operating parameter assumes a value that is provided for the operation of the laser spark plug.
• the beam shape The laser radiation, in particular the beam position, beam dimensions and distances between the beam and the diaphragm are understood to be in accordance with and / or in the context of the standard DIN EN ISO 11145.
• the providence that the distance between the diaphragm and laser radiation does not exceed a maximum distance, at least along predominant parts of the inner contour of the diaphragm, on the one hand is based on the knowledge that it is effective for achieving a combustion chamber window shielding effect and for reducing deposits on the combustion chamber
• Combustion chamber window along predominant parts of the inner contour of the aperture, in particular along the entire inner contour of the aperture is conducive when the passage of the aperture is designed as narrow as possible.
• this requirement is contrary to the fact that the largest possible proportion of guided through the means for guiding, shaping and / or for generating laser radiation, shaped and / or generated laser radiation should pass through the aperture, so the aperture must not be too narrow, in particular , as also manufacturing tolerances are to be considered.
• the predominant parts of the inner contour of the diaphragm may comprise 70% of the surface of the inner contour or more, 90% of the surface of the inner contour or more or even the entire inner contour.
• a diaphragm for the passage of the guided, shaped and / or generated laser radiation through the means into a combustion chamber, wherein the inner contour of the diaphragm has the shape of the lateral surface of a truncated cone, wherein the truncated cone has an opening angle ⁇ ,
• Focusing means for determining a beam divergence angle ⁇ of the laser beam passing through the aperture is provided, wherein 0 ⁇ - ⁇ ⁇ 30 °,
• the beam shape of the laser radiation in particular the beam divergence angle, beam position, beam dimensions and distances between beam and diaphragm are understood according to and / or against the background of the standard DIN EN ISO 11 145.
• the design and the effect of the focusing agent the above applies. Due to the feature that 0 ⁇ - ⁇ ⁇ 30 °, in particular 0 ⁇ - ⁇ ⁇ 30 ° results in the technical effect that an outlet cross-section of the aperture is relatively narrow, so that only a few particles can enter the interior of the aperture, itself but the aperture in their combustion chamber window facing part widens relatively strong, whereby the areal extent of the inner contour of the aperture is relatively large.
• the penetrated by the laser radiation surface of the combustion chamber window is due to the lower
• Beam divergence angle ⁇ relatively small. Overall, these surface ratios result in the majority of the few, in the aperture, from the outset
• the inner contour of the diaphragm has the shape of the lateral surface of a straight circular truncated cone, wherein the straight circular truncated cone has the opening angle ⁇ , where 0 ⁇ - ⁇ ⁇ 30 °, in particular 0 ⁇ - ⁇ ⁇ 30 °.
• the opening angle ⁇ has 90 ° or less, in particular 70 ° or less, preferably 60 ° or less, and / or that the opening angle ⁇ is 3 ° or more, in particular 10 ° or more, and or 5 ° ⁇ ⁇ - ⁇ , in particular 13 ° ⁇ - ⁇ and / or that ⁇ - ⁇ ⁇ 20 °, in particular ⁇ - ⁇ ⁇ 15 °.
• Fluid connection between an interior of the pre-chamber and a surrounding the antechamber combustion chamber allows.
• measures for influencing the flow in the areas mentioned can also be provided in devices not covered by the laser spark plug, for example by the design of the shape of the
• Combustion chamber or the piston associated with the combustion chamber or other components of the internal combustion engine is Combustion chamber or the piston associated with the combustion chamber or other components of the internal combustion engine.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the means an aperture for the passage of the guided through the means, shaped and / or generated laser radiation in an on the opposite side of the combustion chamber window
• At least one fluid passage between an interior of the prechamber and a combustion chamber surrounding the prechamber enabling overflow is provided that the at least one overflow is arranged and designed so that when flowing in a fluid through the overflow in the interior of the prechamber results in a desired fluid flow.
• the at least one overflow channel has a cross section which is not larger, in particular smaller, than the one
• the at least one overflow channel has a cross section QÜ which is not larger, in particular smaller than a maximum cross section, the maximum cross section being 10 mm 2 , 6 mm 2 , 4 mm 2 , 2 mm 2 or 1 mm 2 can be.
• Overflow channels LQ high compared to a cross section Qu of at least one Overflow channel is, in particular according to LQ> (Qü / ⁇ ) 172 ,> (16 * 0. ⁇ / ⁇ ) 1/2 or Lo> (36 * ⁇ / ⁇ ) 1/2 .
• the targeted influencing of the fluid flowing into the prechamber results in a reduction of the deposits on the combustion chamber window and thus an improvement in the reliability of the laser spark plug.
• Be considered combustion chamber window lying cylindrical or towards the combustion chamber tapered region of the laser spark plug while under the pre-chamber in particular a combustion chamber side of the diaphragm arranged region of the laser spark plug can be considered, in particular at least partially has a relation to the entire aperture or the outlet opening of the aperture enlarged cross-section.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the opposite side of the center of the combustion chamber window, a diaphragm for the passage provided by the means guided, shaped and / or generated laser radiation in an arranged at the combustion chamber end of the housing antechamber, wherein at least one fluid connection between an interior of the pre-chamber and the combustion chamber surrounding the combustion chamber enabling Studentsströmkanal is provided that the at least one overflow arranged and is formed so that when a fluid flows through the overflow into the interior of the pre-chamber, a fluid flow results in the interior at a finite minimum angle, in particular measured to the longitudinal axis of the laser spark plug the aperture occurs.
• Minimum angle ⁇ in particular measured to the longitudinal axis of the laser spark plug, enters the interior of the diaphragm, on the one hand results in the effect that the inflowing fluid is directed to the inner contour of the diaphragm and stored particles contained in the fluid there.
• the number of particles reaching the combustion chamber window can thus be reduced, the deposits on the combustion chamber window are reduced and the reliability of the laser spark plug is increased.
• the described effect already occurs when the minimum angle ⁇ is 45 °, even more favorable minimum angles ⁇ are 60 ° or 75 ° or 85 °, in each case in particular measured with respect to the longitudinal axis of the laser spark plug.
• the measurement of the minimum angle is always possible also to a vertical on the entrance surface of the diaphragm and / or to a vertical on a, the combustion chamber facing surface of the combustion chamber window.
• the at least one overflow channel is arranged so that its longitudinal axis in the radial direction forms an angle with the longitudinal axis of the laser spark plug, which is less than about 25 °, preferably less than about 10 °.
• a plurality of overflow channels are provided.
• additional means are provided, through which a purge gas is blown into the prechamber, and these means are arranged in particular and are operable so that together with the fluid flowing through the overflow
• Outlet opening of the aperture is.
• the flow is formed within the antechamber as a tumble flow.
• the above-explained effect of providing the minimum angle ⁇ acts synergistically with a given minimum angle ⁇ with a particularly long diaphragm and / or with a particularly slender diaphragm, in particular a diaphragm with a small outlet cross-section QBA, through which the fluid flow enters the interior of the diaphragm because in such developments, the inner contour of the diaphragm is hit by the fluid flow particularly close to its combustion chamber end and particles are preferably deposited there on the inner contour of the diaphragm. It is preferred that the inner contour of the diaphragm is struck by the fluid flow in a half of the inner contour of the diaphragm facing the combustion chamber. Even more favorable is an impact of the fluid flow in a combustion chamber facing end portion whose length in the longitudinal direction of the inner contour 1 / n of
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or for generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the opposite side of the center of the combustion chamber window,
• a diaphragm for the passage of the guided, guided and / or generated by the means laser radiation in an arranged at the combustion chamber end of the housing antechamber, wherein at least one fluid connection between an interior of the prechamber and a surrounding the antechamber
• combustion chamber enabling overflow that the at least one overflow is arranged and designed so that when a fluid flows through the overflow into the interior of the pre-chamber, a fluid flow which has at least one vortex in the region of the aperture, which is a vortex axis which rotates a component in the direction of the longitudinal axis of the
• an area of the diaphragm upstream of the diaphragm and / or a region of the outlet opening of the diaphragm is to be understood as being under the region of the diaphragm.
• Spaces are to be understood in particular as meaning spatial regions which have structure lengths which are somewhat smaller, for example half as large or one quarter as large as a structure length of the inner contour of the diaphragm, the structural length being characterized in particular by length,
• Entry diameter and / or exit diameter of the diaphragm can be given.
• Flow channels initially results in that the fluid flow in the region of the diaphragm has a component in the direction perpendicular to the longitudinal axis LA of the laser spark plug. Furthermore, owing to the vortex, a flow deflection results locally in a direction perpendicular to the local flow velocity. Since the particles transported by the flow have a finite inertia, they only follow this flow deflection to a limited extent and tend, especially in the case of sharp flow deflection, to strike the inner contour of the diaphragm or a side wall of the antechamber. Overall, the result is that the amount of the combustion chamber window reaching particles is reduced, so that deposits on the combustion chamber window is reduced and the reliability of the laser spark plug is increased.
• the swirl axis has only one component in the direction of the longitudinal axis of the laser spark plug, it is preferred that the swirl axis is at an angle with a longitudinal axis of the laser spark plug of at most 45 °, in particular at most 20 °, preferably at most 10 °, or parallel with the longitudinal axis LA of the laser spark plug.
• the vortex axis is parallel to the longitudinal axis LA of the laser spark plug, in addition to the coaxial arrangement and a spaced arrangement of the swirl axis and the longitudinal axis LA of
• Laser spark plug favorably, in particular if the distance between the swirl axis and longitudinal axis LA of the laser spark plug is at least 2 mm, in particular at least 4 mm. The maximum distances are 6 and 10mm. The result of the spacing is a shear flow perpendicular to the outlet opening of the diaphragm and the impact of the particles on the inner contour of the diaphragm.
• the intended arrangement of the overflow channel can result, in particular, from the fact that its longitudinal axis in the tangential direction encloses an angle with the longitudinal axis of the laser spark plug which is more than approximately 10 °, preferably more than approximately 25 °.
• additional means are provided, through which a purge gas is blown into the prechamber, wherein the additional means are arranged and are operable so that together with the through the
• Overflow bore inflowing fluid results in a resulting total flow that forms a vortex as discussed above. It is always preferred that the flow within the antechamber is formed as a swirl flow.
• a laser spark plug for an internal combustion engine comprising at least one means for guiding, shaping and / or for generating laser radiation, further comprising a combustion chamber window and a housing, wherein the housing on the opposite side of the center of the combustion chamber window,
• a diaphragm for the passage of the guided, guided and / or generated by the means laser radiation in a combustion chamber, that the aperture on a side facing the combustion chamber has at least one outer edge whose contour against a sharp-edged
• sharp edge reference is made to the standard DIN ISO 13715: 2000.
• an outer edge is considered sharp-edged, if only
• the outer edge of the diaphragm can in particular limit the inner contour of the diaphragm.
• the outer edge of the diaphragm can in particular also be spaced from the inner contour of the diaphragm, in particular a radially outer one
• Limiting the aperture and / or the housing represent at its combustion chamber end.
• the providence of the deviation of the contour of the outer edge inward is based on the knowledge that laser spark plugs operate in an internal combustion engine
• Deviation of the contour of the outer edge inwards areas become so high Temperature increases avoided and as a result, the occurrence of pre-ignition in the combustion chamber can be avoided.
• the diaphragm has on at least one outer edge on a side facing the combustion chamber whose contour deviates inwardly relative to a sharp-edged outer edge
• the outer edge consist of a sharp-edged outer edge by an ablation of more than 0.075 mm , in particular of 0, 1 mm or more, preferably 0, 15 mm or more apparent. 5 mm, 2 mm and 0.5 mm are considered as the upper limit for the ablation, as excessively large abradings could impair the mechanical stability of the diaphragm.
• the outer edge of the panel a
• the radius of curvature, in the case of chamfering, the depth and / or the width of the chamfer has 0.075 mm or more, in particular 0.15 mm or more.
• the radius of curvature, in the case of chamfering, the depth and / or the width of the chamfer be 5 mm or less, in particular 2 mm or less, preferably 0.5 mm or less.
• the diaphragm is designed as a separate component and is attached to a further part of the housing of the laser spark plug, in particular on a shoulder. It is preferred to ensure a good dissipation of heat from the panel, which can be done by the joint between the panel and another part of the housing good thermal conductivity, in particular by means of a large-area soldering (at least 10 mm 2 , in particular at least 20 mm 2 ) and / or waiving welds, for example by a press fit executed.
• the panel can also be screwed to the further part of the housing with a thread, wherein it is preferred is to provide a screw connection by means of a fine thread (thread pitch ⁇ 0.5 mm, in particular ⁇ 0.3 mm).
• a spark is preferably generated at least 1 mm, preferably at least 2 mm outside the diaphragm.
• the distance between spark and exit surface of the diaphragm additionally or alternatively 30 mm, 10 mm and 5 mm into consideration, otherwise the exit cross section of the aperture would have to be chosen excessively large or a sufficient focusing of the laser radiation would be difficult.
• the position of a focus of the laser radiation generated or shaped by the laser spark plug can be regarded as the position of the spark.
• combustion chamber also fixed to the laser spark plug or fixed to the laser spark plug pre-chamber includes, in particular an antechamber whose volume is less than 10 cm 3 and which has at least one overflow channel whose cross-section less than 5 mm 2 .
• Figure 1a is a schematic representation of an internal combustion engine with a
• Figure 1 b is a schematic representation of the laser ignition device of Figure 1 and
• An internal combustion engine carries in Figure 1a overall as reference numeral 10. It can be used to drive a motor vehicle, not shown.
• the internal combustion engine 10 comprises a plurality of cylinders, of which only one is designated by the reference numeral 12 in FIG.
• a combustion chamber 14 of the cylinder 12 is limited by a piston 16.
• Fuel or premixed fuel-air mixture enters the combustion chamber 14 through an injector 18, which is connected to a designated also as a rail fuel pressure accumulator 20.
• injected fuel 22 or pre-mixed fuel-air mixture is ignited by means of a laser radiation 24, the one of
• Laser spark plug 100 comprehensive ignition device 27 is emitted into the combustion chamber 14.
• the laser spark plug 100 is fed via a light guide device 28 with a light, which may be in particular pump light, which is provided by a light source 30.
• a light which may be in particular pump light, which is provided by a light source 30.
• the immediate provision of provided for the ignition light may be provided by the light source 30.
• the light source 30 is controlled by a control unit 32, which also controls the injector 18.
• the light source 30 feeds a plurality of optical fiber devices 28 for different laser spark plugs 100, each of which has a cylinder 12
• the light source 30 has a plurality of individual laser light sources 340, which are connected to a pulse power supply 36.
• a "stationary" distribution of light, in particular pump light is realized on the various laser spark plugs 100, so that no optical distributors or the like are required between the light source 30 and the laser spark plugs 100.
• the light source 30 also have only one laser light source 340.
• each laser spark plug 100 is assigned exactly one light source 30 and / or exactly one laser light source 340.
• the laser spark plug 100 has, for example, a laser-active solid 44 with a passive Q-switching circuit 46, which forms an optical resonator together with a coupling-in mirror 42 and an output mirror 48.
• further optical components in particular lenses, for example for shaping the radiation supplied to the laser spark plug 100 or for expanding radiation, may be provided.
• the laser spark plug 100 By applying light generated by the light source 30, in particular pumping light, the laser spark plug 100 generates laser radiation 24 in a manner known per se, which is focused by focusing optics 52 onto an ignition point ZP located in the combustion chamber 14 (FIG.
• the components present in the housing 38 of the laser spark plug 100 are separated from the combustion chamber 14 by a combustion chamber window 58.
• Combustion chamber window 58 is sealingly connected to the housing 38.
• the seal between the housing 38 and the combustion chamber window 58 may be formed in the region of the reference numeral 60 in the form of a cohesive or frictional connection.
• the housing 38 may, as in these examples, be formed in two parts. It comprises an inner sleeve 62 and an outer sleeve 64.
• the outer sleeve 64 has a shoulder 66 on an end facing the combustion chamber 14 (see FIG. 1a).
• sealants such as sealing rings, in particular steel sealing rings, preferably copper-coated steel sealing rings, can be used and
• a female thread is provided on the outer sleeve 64, which cooperates with a corresponding bolt thread of the inner sleeve 62.
• This thread consisting of female thread and bolt thread, is in its entirety with the
• Inner sleeve 62 is formed between the shoulder 66 and the combustion chamber window 58, a further sealing surface 72nd
• a focusing lens 52 (see Figure 1a and 1b), which generated in the laser spark plug 100 or the laser spark plug 100 fed laser radiation 24 to the ignition point ZP, the in this example corresponds to the focal point of the focusing optics 52, focused.
• a diaphragm 74 At the combustion-chamber-side end 381 of the housing 38, there is a diaphragm 74 for the passage of the laser radiation 24 into the combustion chamber 14
• the laser spark plug 100 shown in Figure 2 has a housing 38, whose combustion chamber side of the combustion chamber window 58 arranged portion is sleeve-shaped and an aperture 74 according to the invention.
• the inner contour 71 of the diaphragm 74 has, for example, the shape of a cylinder jacket whose height corresponds to the length L of the diaphragm 74.
• the length L is measured, for example, starting from the combustion chamber window 58, in the longitudinal direction of the laser spark plug and is 13 mm in this example.
• This length L of the aperture 74 is also contemplated in the other embodiments and examples of the invention.
• the diaphragm 74 is made of a material having a thermal conductivity of 60 W / (m * K) or more or even having a thermal conductivity of 80 W / (m * K) or more, for example brass, Alloy or nickel or copper or at least one of these substances.
• the entire housing 38 is made of this material in this example.
• the provision of the material only inside the panel, enclosed by other material whose thermal conductivity may be lower, for example, from a high-alloy steel, is possible. Such a variant is shown in FIG.
• remote area of the housing 38 for example by circulation of water or other cooling medium, are discharged.
• FIG. 5 shows an example of a laser spark plug, which differs from the previous ones
• a gap 82 is arranged.
• the gap 82 is delimited axially on the side facing the combustion chamber 14 by the diaphragm 74, on the side facing away from the combustion chamber 14 through the combustion chamber window 58 and outwardly through the diaphragm 74.
• the gap 82 communicates via the interior of the diaphragm 74 with an area lying in front of the diaphragm 74, for example a combustion chamber 14.
• the gap 82 in this example has the base area of a ring having an outer diameter D SA of 15 mm and an inner diameter D. S i of 6 mm, so that the gap cross-section Q s 148 mm 2 .
• the gap cross-section Q s is thus a multiple of the
• the height H s of the gap 82 in this example is 0.15 mm.
• the height of the gap is 2 mm and the gap cross-section Q s is only 20% of the inlet cross-section Q BE of the diaphragm 74, namely 0.56 mm 2 .
• FIG. 6 shows a further example of a laser spark plug 100, which differs from those illustrated above in that the diaphragm 74 has a particularly small size Outlet cross-section Q BA , which is 3 mm 2 in this example, with an outlet diameter D B A of the aperture of 2 mm.
• the length L, the aperture 74 is 12 mm in this example, so that the value of 6 results for the quotient U (4Q BA /) V2 .
• FIG. 7 a further example of a laser spark plug is shown, which differs from those shown above differs in that the inner contour of the aperture 74 in a region which of both the combustion chamber facing the end of the aperture 74 and the Distinguished combustion chamber facing away from the end of the aperture 74, at least one edge 83, in particular a plurality of edges 83, has.
• the laser spark plug 100 shown in FIG. 7 has a diaphragm 74 which has two edges 83, an inner edge and an outer edge in a central region, which together form a step 84 formed at right angles.
• steps 84 show a laser spark plug 100 having a multiplicity of edges 83 and rectangular steps 84 formed therefrom, the number of steps 84 actually represented being representative of, for example, 3, 7 or 8 stages, in particular in a central one Area of the aperture 74 are arranged. Even non-rectangular steps 84 are possible.
• steps 84 are also possible, at which the diaphragm 74 tapers in the direction of its end facing away from the combustion chamber 14.
• FIG. 9 shows an example in which such stages 84, at which the diaphragm 74 tapers in the direction of its end facing the combustion chamber 14, are upstream of the combustion chamber side.
• FIG. 10 shows a further example of a laser spark plug 100 with a diaphragm 74 whose inner contour 71 has a circumferential edge 83.
• FIGS. 1 to 15 each show a further example of a laser spark plug 100, which has an aperture 74, with the special feature that the inner contour 71 of the aperture 74 is in a region which extends from the end of the aperture 74 facing the combustion chamber 14 as well as from the combustion chamber 14 facing away from the end of the aperture 74 is spaced, having an extreme cross-section Q x .
• the laser spark plug 100 shown in FIG. 11 has an aperture 74 which has a sharp-edged constriction 85 in a central area.
• the diameter D x and thus the cross section of the aperture Q x is minimal, namely approximately half or quarter as large as respectively the inlet and the outlet cross section Q B E , QB A of the diaphragm.
• the inner contour 71 of the aperture 74 in this example in each case in the form of straight circular truncated cone coats on.
• FIG. 13 has a diaphragm 74 which has a sharp-edged bulge 86 in a central region.
• the diameter D x and thus the cross-section of the diaphragm Q x is a maximum, namely about twice to four times as large as in each case the inlet and outlet cross-section Q B E, QBA of the diaphragm.
• the inner contour 71 of the aperture 74 in this example in each case in the form of straight Kreistrgelstumpfmänteln.
• Figure 15 shows a further variant in which the aperture 74 has an undercut 87. The undercut is executed in this example as mecanicokstich and rectangular and has a maximum cross-section of the aperture Q x , which is about twice to four times as large as each of the inlet and outlet cross-section Q B E , QBA the aperture.
• FIGS. 16 and 17 a further example of a laser spark plug 100 is shown, which has a diaphragm 74, with the special feature that the diaphragm 74 has at least one outer edge 88 on the side facing the combustion chamber 14, whose contour follows a sharp-edged outer edge deviates inside.
• the laser spark plug 100 shown in FIG. 16 has an aperture 74 with a sleeve-shaped basic shape, wherein the inner edge 89 of the inner combustion chamber side has a rounding 91.
• the fillet radius is 0.5 mm in this example.
• the rounding 91 of the outer combustion chamber side edge 90 of the sleeve is additionally or alternatively, for example, with a radius of curvature of 0.5 mm is possible.
• the laser spark plug 100 illustrated in FIG. 17 has an aperture 74 with a sleeve-shaped basic shape, the inner combustion chamber-side edge 89 of the sleeve having a chamfer 92.
• Chamfer 92 (length and width) in this example is 0.5 mm, the chamfer angle is 45 °.
• the chamfer 92 of the outer combustion chamber side edge 90 of the sleeve is additionally or alternatively, for example, with a length and width of 0.5 mm, possible. Even small and / or larger chamfer 92 are possible in principle.
• outer edges 88 can be executed whose contour deviates inwardly from a sharp-edged outer edge, for example, outer edges with an exact or approximate elliptical, parabolic or hyperbolic shape or with an irregular shape. Combinations of chamfers 92 and fillets 91 are also conceivable.
• FIGS. 18 and 19 each show a further example of a laser spark plug 100 which has an aperture 74 and which has focusing means 53, in particular focusing optics 52, for defining a beam shape of the laser radiation 24 passing through the aperture 74 (see FIG. 1B).
• the ones suggested in these examples Laser spark plugs 100 have the special feature that the shape of the diaphragm 74 is advantageously chosen with regard to the shape of the laser radiation 24 passing through it.
• the shape of the laser radiation 24 is indicated in these figures by the conical envelope lines 99 which intersect approximately at the ignition point ZP.
• the information concerning the shape of the laser radiation 24 is understood in accordance with or in the context of the standard DIN EN ISO 11 145.
• the laser spark plug 100 illustrated in FIG. 18 has an aperture 74 which, along its entire inner contour 71, is at a distance A from the one passing through it
• the illustrated laser spark plug 100 also has the property that 88% of the transmitted through the combustion chamber window 58 laser radiation 24 passes through the aperture 58 as focusable laser radiation 24, while the remaining laser radiation 24 along the inner contour 71 of the aperture 74 undergoes a deflection or absorption and for a Focusing is not available.
• the laser spark plug 100 illustrated in FIG. 19 has a diaphragm 74 whose
• Inner contour 71 has the shape of a straight circular truncated cone, the opening angle ⁇ is 45 °. The passing through the aperture laser radiation 24 is in this
• FIGS. 20 and 21 each show an example of a laser spark plug 100 which has an aperture 74 for the passage of laser radiation 24 into an antechamber 1 10 arranged at the combustion chamber end of the housing 38.
• an overflow channel 120 is provided for the fluid connection between the interior 1 1 1 of the pre-chamber 1 10 and the combustion chamber.
• the longitudinal axis KLA of the overflow channel 120 is arranged eccentrically offset with respect to the longitudinal axis LA of the laser spark plug 100.
• the longitudinal axis KLA of the overflow bore 120 and the longitudinal axis LA of the laser spark plug 100 are parallel to each other in this example, alternatively, they may also be arranged at an angle to each other in the radial and / or tangential direction.
• a vortex forms within the prechamber 110 in such a way that the fluid flow runs along the outlet opening of the diaphragm 74 substantially parallel to the outlet opening of the diaphragm 74.
• the fluid flow forming inside the orifice 74 represents, in particular, a tumble flow.
• the length L of the orifice is 5 mm and the orifice diameter D A E of the orifice is 6 mm. It is thus through the
• Overflow 120 is arranged and designed so that when flowing a fluid through the overflow 120 into the interior 1 1 1 of the prechamber 1 10 results in a fluid flow F, which at a minimum angle ⁇ , in particular measured to the longitudinal axis of the laser spark plug, of 45 °, 60 ° or 75 ° enters the interior of the aperture 74 are possible and in particular provide that a plurality of overflow 120 are provided. Additionally or alternatively, it is also possible that additional means (not shown) are provided, through which a purge gas is blown into the prechamber. It is provided in particular that these means for injecting purge gas together with the
• Overflow channel 120 cooperate in a manner that a total of one
• Overflow passage 120 into the interior 1 11 of the pre-chamber 110 results in a fluid flow F, which at a minimum angle ⁇ , in particular measured to the longitudinal axis of the
• Laser spark plug from 45 °, 60 ° or 75 ° into the interior of the aperture 74 occurs.
• FIG. 21 shows a further example of a laser spark plug 100, in part a as a partial longitudinal section along the longitudinal axis LA of the laser spark plug 100, in part b in a view in direction B in part a and in part c in a section along the line CC in part b of the figure 21.
• This laser spark plug 100 has for the fluid connection between the interior 11 1 of the pre-chamber 110 and the combustion chamber five transfer ports 120 which are offset by 72 ° to each other, symmetrically.
• Overflow holes 120 are inclined in both the radial and in the tangential direction, such that the longitudinal axes KLA of the overflow holes 120 in plan view of the
• Laser spark plug ( Figure 21 b) form a regular pentagon. Due to the arrangement and the orientation of the overflow bores 120, a vortex forms during the inflow of a fluid F into the prechamber 110, the vortex axis WB of which inside the prechamber 110 and in the region of the diaphragm 74 with the longitudinal axis LA of the laser spark plug 100
• the fluid flow forming inside the orifice 74 represents, in particular, a swirl flow.
• additional means are provided, through which a purge gas is blown into the pre-chamber 110. It is provided in particular that these means for injecting purge gas together with an overflow channel 120 or more overflow channels 120 cooperate in such a way that a total of a fluid flow is formed, so that when flowing in a fluid through the
• Overflow channel 120 or the overflow into the interior 111 of the pre-chamber 10 results in a fluid flow having a vortex, which rotates about a vortex axis WB having a component in the direction of the longitudinal axis LA of the laser spark plug 100, in particular parallel or coaxial with the longitudinal axis LA the laser spark plug 100 is.

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• Combustion & Propulsion (AREA)
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• General Engineering & Computer Science (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
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• 2010
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