DE102021120984B3 - Crankcase for an internal combustion engine - Google Patents

Abstract

The invention relates to a crankcase (1) for an internal combustion engine (2), having at least one cylinder (3) with a cylinder center (4) and with a running surface (5) for a piston (6); and- at least one cooling jacket (7) for cooling the running surface (5) of the cylinder (3), the cooling jacket (7) comprising:- at least one annular channel (8,9,10), of which around the cylinder center (4). circulation path (11) is formed, and at least one branch duct (12,13) aligned transversely to the annular duct (8,9,10) and having a central region (14), the annular duct (8,9,10) being operated with coolant can be supplied, and wherein the ring channel (8,9,10) and the branch channel (12,13) are connected to one another by means of a bulge (15). The crankcase (1) is primarily characterized in that the bulge (15) is arranged in relation to the branch duct (12,13) in such a way that between: - the central area (14) of the branch duct (12,13) and- a ring section (16,17) of the ring channel (8,9,10) with a circumferential distance of at least 30° of the circular path (11) to the central area (14) of the branch channel (12,13) a free line of sight (18) is formed. With the crankcase proposed here, a cleaning nozzle for removing material from a lost core can be placed in such a way that the cleaning liquid can penetrate deep into an annular channel and cleaning is thus simplified.

Description

The invention relates to a crankcase for an internal combustion engine, an internal combustion engine with such a crankcase, a mold for such a crankcase, and a cleaning method for such a crankcase.

It is known from the prior art to cool the running surfaces (possibly part of separate liners) of a cylinder of an internal combustion engine in a crankcase. In this case, a plurality of ring channels are provided, which are set up for conducting a coolant and are arranged in the crankcase as closely as possible to the running surface and surround the running surface. The crankcase is made by casting, for example from aluminium. Such a ring channel must be created with a lost (e.g. sand or salt) core. The lost core is removed again after the casting process. It must be ensured that no core residues remain in the ring channel, otherwise the hydraulic cross section of the ring channel is reduced and/or the coolant is contaminated and the mechanical parts in the cooling circuit (e.g. pump and/or valves) can be damaged. This is currently ensured with shaking and rinsing and, if necessary, with ultrasonic cleaning, as well as with a subsequent test step.

From the DE 10 2019 110 566 A1 a crankcase and a method for its production are known, wherein the crankcase has cylinder running paths for pistons, and the crankcase has cooling jackets adjacent to the cylinder running paths, in top dead center areas of the pistons, with the respective cooling jacket having a coolant inlet and a coolant outlet, and the respective cooling jacket in a plurality of circumferential cooling channels is divided. According to paragraph [0019], the coolant inlet of the cooling jacket is arranged diametrically to the coolant outlet of the cooling jacket

From the JP H04-295 164A a cooling device for an internal combustion engine is known, in which two connecting channels 22, 23 are connected to a plurality of annular grooves 11. At least one intermediate piece 34 is introduced into these connecting channels 22, 23, a coolant being throttled and a flow rate of the coolant to an upper part of the combustion chamber being increased by means of the differently sized openings 34b introduced into the intermediate piece 34.

From the DE 10 2019 112 918 B3 core is known for use in the production of a crankcase by casting. According to the summary, the core has a first core part 2 with core webs 3 for the formation of the respective cooling jacket having the cooling channels and a support structure 4 for the first core part 2 . With such a core, it is provided that the support structure 4 has a plurality of second core parts 5, which are connected to the first core part 2 in the area of its core webs 3, and the support structure 4 has a third core part 6, which is spaced apart from the first core part 2 with the second core parts 5 is connected.

Furthermore, from the DE 10 2016 125 619 A1 a cylinder housing and a method for producing a cylinder housing and a casting core are known, with the cylinders 12 being surrounded on the circumference by a cooling jacket, in which the cooling jackets are divided into a plurality of closed, circumferential cooling channels 42 and in which a coolant inlet 44 is provided in at least one of the cooling jackets and a coolant outlet 46 opens into at least one of the cooling jackets. The cooling channels 42 are fluidically connected to one another between the cylinders 12 .

Proceeding from this, the object of the present invention is to at least partially overcome the disadvantages known from the prior art. The features according to the invention result from the independent claims, for which advantageous configurations are shown in the dependent claims. The features of the claims can be combined in any technically meaningful way, whereby the explanations from the following description and features from the figures can also be used for this purpose, which include additional configurations of the invention.

• - zumindest einen Zylinder mit einem Zylinderzentrum und mit einer Lauffläche für einen Kolben; und
• - zumindest einen Kühlmantel zum Kühlen der Lauffläche des Zylinders, wobei der Kühlmantel umfasst:
  • - zumindest einen Ringkanal mit einem hydraulischen Durchmesser, von welchem um das Zylinderzentrum ein Umlaufweg gebildet ist, und
  • - zumindest einen zu dem Ringkanal quer ausgerichteten Stichkanal mit einem Zentrumsbereich und mit jeweils einem hydraulischen Durchmesser,

wobei der Ringkanal im Betrieb mit Kühlmittel versorgbar ist,
wobei der Ringkanal und der Stichkanal mittels einer Ausbuchtung miteinander verbunden sind, und
wobei der hydraulische Durchmesser des Ringkanals kleiner als 35% des hydraulischen Durchmessers des Stichkanals ist.The invention relates to a crankcase for an internal combustion engine

• - At least one cylinder with a cylinder center and with a running surface for a piston; and
• - at least one cooling jacket for cooling the running surface of the cylinder, the cooling jacket comprising:
  • - at least one annular channel with a hydraulic diameter, from which a circulation path is formed around the center of the cylinder, and
  • - at least one branch channel aligned transversely to the annular channel with a central area and each with a hydraulic diameter,

wherein the ring channel can be supplied with coolant during operation,
wherein the ring channel and the branch channel are connected to one another by means of a bulge, and
wherein the hydraulic diameter of the ring canal is less than 35% of the hydraulic diameter of the branch canal.

• - dem Zentrumsbereich des Stichkanals und
• - einem Ringabschnitt des Ringkanals mit einem Umlaufabstand von mindestens 30° des Umlaufwegs zu dem Zentrumsbereich des Stichkanals eine freie Sichtlinie gebildet ist.

The main feature of the crankcase is that the bulge is arranged in relation to the branch channel in such a way that between:

• - the central area of the branch canal and
• - A clear line of sight is formed in a ring section of the ring channel with a circumferential distance of at least 30° of the circumferential path to the central region of the branch channel.

Unless explicitly stated otherwise, ordinal numbers used in the description above and below only serve to clearly distinguish them and do not reflect any order or ranking of the designated components. An ordinal number greater than one does not mean that another such component must necessarily be present.

The crankcase proposed here is, for example, identical in terms of its function to a conventional crankcase, and preferably compatible with an otherwise conventional internal combustion engine in terms of its size and connections. The crankcase is primarily formed by means of a casting mold which (apart from the special features mentioned here) is preferably designed and usable in a conventional manner and/or is designed, for example, as explained in more detail below. The crankcase preferably includes what is known as performance cooling for the running surface of the relevant cylinder. The tread is concentric with the cylinder center and extends parallel to the cylinder center. For this purpose, the crankcase comprises one or a plurality of cylinders for a corresponding number of pistons, which move up and down in the corresponding cylinder during a work step during operation. A running surface is created in the cylinder with suitable surface properties (e.g. roughness and flatness) for a well-sealed operation. In one embodiment, the running surface is formed by a liner inserted into the cylinder. The running surface is preferably formed in one piece with the rest of the crankcase.

The cooling jacket for the running surface is formed inside and integrally with the crankcase, so that the best possible heat transfer is formed, for example by means of the smallest possible wall thickness, between the cooling-effective portion of the cooling jacket and the running surface. The cooling jacket comprises at least one ring channel, preferably a plurality of ring channels. The (at least one) ring channel can be supplied via a separate supply line and/or a branch channel. Such a separate supply line is, for example, a so-called feed funnel. The ring channel is formed at least over a partial section around the running surface and thus around the center of the cylinder, for example offset radially outward concentrically or ovally. A part of the effective cooling portion of the cooling jacket is formed by the annular channel, or the effective cooling portion of the cooling jacket is formed solely by the annular channel. In one embodiment, the ring channel is formed in a plane to which the center of the cylinder is aligned perpendicularly. Alternatively, such an annular channel is inclined towards the center of the cylinder and runs, for example, in a thread-like manner around the running surface. In one embodiment, the annular portions of the annular channel are not in a mathematically constant plane over a circular path. The plane of the annular canal is therefore considered in further consideration as such a surface in which the free line of sight described further below lies.

• - der Stichkanal erstreckt sich entlang (bevorzugt parallel zu) der Erstreckung des Zylinderzentrums beziehungsweise der Zylinderachse;
• - der Stichkanal weist einen Querschnitt auf, welcher größer ist als, bevorzugt mindestens doppelt so groß ist wie, das Doppelte der Summe der Strömungsquerschnitte der Ringkanäle;
• - der Stichkanal erstreckt sich (entlang der Erstreckung des Zylinderzentrums beziehungsweise der Zylinderachse) über die gleich-gerichtete Erstreckung des zumindest einen Ringkanals;
• - der Stichkanal erstreckt sich durch das Kurbelgehäuse hindurch;
• - der Stichkanal ist unmittelbar nach dem Urformen und nach dem Entfernen des zum Bilden des Stichkanals eingesetzten Kerns nach außen offen;
• - der Stichkanal ist vor der Inbetriebnahme des Kurbelgehäuses in einer Verbrennungskraftmaschine mittels eines Dichtmittels, beispielsweise mittels eines separaten Verdrängungskörpers verschlossen, und damit nicht als Versorgungsleitung für den zumindest einen Ringkanal eingerichtet;
• - der Stichkanal ist mit seinem Querschnitt derart angeordnet, dass der gesamte Stichkanal oder zumindest sein Zentrumsbereich sich nicht mit einer (theoretischen, kontinuierlichen) Fortsetzung des zumindest einen Ringkanals überlappt, bevorzugt den zumindest einen Ringkanal tangiert;
• - mittels der Ausbuchtung der Zentrumsbereich (oder der gesamte Stichkanal) und der Ringkanal mit einem ergänzenden Volumen verbunden sind.

In one embodiment, the branch channel is designed as a through hole for screwing the crankcase in an internal combustion engine. Alternatively or additionally, in one embodiment, the branch channel has at least one of the following properties:

• - The branch channel extends along (preferably parallel to) the extension of the cylinder center or the cylinder axis;
• - The branch channel has a cross section which is greater than, preferably at least twice as large as, twice the sum of the flow cross sections of the ring channels;
• - The branch channel extends (along the extension of the cylinder center or the cylinder axis) over the same-directed extension of the at least one annular channel;
• - The branch channel extends through the crankcase;
• - The branch channel is open to the outside immediately after the primary shaping and after the removal of the core used to form the branch channel;
• - Before the crankcase is started up in an internal combustion engine, the branch channel is closed by means of a sealant, for example by means of a separate displacement body, and is therefore not set up as a supply line for the at least one annular channel;
• - the cross-section of the branch channel is arranged in such a way that the entire branch channel or at least its central area does not overlap with a (theoretical, continuous) continuation of the at least one ring channel, preferably touches the at least one ring channel;
• - by means of the bulge, the central area (or the entire branch canal) and the ring canal are connected to an additional volume.

In the embodiment proposed here, the branch channel and the ring channel are connected to one another, for example fluidly connected or, when used, separated from one another (almost or completely fluid-impermeable) by a separate displacement body (introduced later) in the branch channel.

So that core remains can be removed reliably and with little effort, it is proposed here that the cross section (in a cutting plane transverse to the cylinder center of the corresponding cylinder) of the puncture channel is arranged in such a way that a free line of sight, i.e. a straight line without intersections with the structure of the Crankcase is formed between an annular portion of the annular channel and the branch channel. The annular section in question is spaced at a circumferential distance of at least 30° [thirty degrees of 360°] from a central area of the branch duct in question via a circumferential path of the annular channel. The central area of the puncture channel is an area in the crankcase that is freely accessible from transversely, for example perpendicularly, to the plane of the annular channel and has such a sufficient cross section that a rigid endoscope with at least one viewing opening (for example a camera lens) that can be aligned in the plane of the annular channel and/or or a cleaning nozzle with at least one nozzle opening that can be aligned in the plane of the ring channel can be inserted without damage (and preferably without the need for material-reducing reworking of the branch channel after demoulding from the mold). The central area is arranged within the stub channel, but not necessarily coaxially to a center of symmetry of the stub channel. In one embodiment, the central area is arranged on the annular channel side tangentially to a cross section or to a segment of the cross section of the annular channel. In one embodiment, the central area has a point of contact or an intersection with said bulge.

The bulge is a structure that widens the ring channel at the branch channel in question towards the branch channel, with the corresponding core volume or a part of this core volume being part of the (first) core for the ring channel in question or for all ring channels in common in one embodiment. In another embodiment, the core volume for the bulge or part of this core volume is formed by the (second) core of the puncture channel. In one embodiment, the core volume for the bulge is at least in part a separate further core.

From the bulge, a local widening of the cross section is formed between the branch channel in question and the ring channel, transversely to the plane of the ring channel, with a radial extent relative to the center of the cylinder. As a result of the suitable design of the bulge, a clear line of sight is formed between the central area of the branch channel in question and from there far into the ring channel, namely by at least a 30° circular path. In one embodiment, the free line of sight is defined by a point within the central area (preferably on the outer edge of the central area) at a distance the amount of which corresponds to at least half the (hydraulic) diameter of the at least one ring channel, from a point closest to the ring channel. This closest point, from which the distance is aligned radially or perpendicular to its tangent to the central area, is preferably a point on a tangent of the central area, which is a (theoretical, continuous) continuation of the at least one annular channel closest and parallel to a tangent is spaced from this continuation at a common radius (perpendicular to both tangents) of the center region. It should be noted that the start of the circulation path is defined here at an (arbitrary, preferably inlet-side edge) point in the center area. In a view of the ring channel in a two-dimensional polar coordinate system, the ring section (or the end angle) to which the free line of sight is formed is, for example, at an absolute angle of 80° to 100° to a (any) reference line (for example an abscissa). and said point of the center region is located at (a starting angle of) about 45° to 50° absolute. In one embodiment, a rigid endoscope, which is inserted into the puncture channel as mentioned above, allows a clear view for checking the completeness of the cleaning, a possibly desired check with little effort. In one embodiment, a cleaning liquid as mentioned above can be introduced from a nozzle opening of a cleaning nozzle (inserted into the branch duct) to such an extent that core residues of the (first) core of the annular duct can be reliably removed. A cleaning liquid ejected from the nozzle opening is deep (along a circulating path) into the annular passage because of small ger deflection of the jet with little damped or undamped impulse, can be introduced. This cleaning method is preferably so reliable that a follow-up check (for example by means of an endoscope and/or ultrasound) is superfluous. In a preferred embodiment, apart from introducing cleaning liquid by means of the cleaning nozzle described above, no further measures for removing core residues from the ring channel are necessary.

In one embodiment, the branch channel is arranged directly adjacent (with a point of contact, ie tangentially) to the cross section of the ring channel or the cross section of the branch channel overlaps with the cross section of the ring channel. In this embodiment, the bulge is then formed purely as a transition channel between the ring channel and the relevant branch channel.

Furthermore, it should be pointed out that the ring channel is not necessarily, but only preferably, designed to be circumferential. Alternatively, the annular duct is only part of a closed ring or is composed of a plurality of such parts, for example four parts, with a supply line and/or the branch duct forming the inlet or outlet for the coolant for the respective annular duct . In an advantageous embodiment, a supply line is provided between two branch ducts (or at the end of the annular duct in the case of a non-circular embodiment of the annular duct) as an outlet or inlet for the coolant. For example, with four evenly distributed branch ducts, such a supply line is arranged centrally between two branch ducts, for example at exactly or approximately 45° [forty-five degrees of 360°] of the circulation path of the ring duct if the circumferential spacing of the branch ducts is exactly or approximately 90°.

It is further proposed here that the hydraulic diameter of the ring channel is less than 35%, preferably less than 25%, of the hydraulic diameter of the branch channel.

In this embodiment, a ring channel with a particularly small hydraulic (second) diameter can be executed, whereby an efficient and cost-effective cleaning process (as described above and/or below, for example) can still be used to ensure that core residues of the lost (first) core are removed from the relevant Ring channel sufficiently, preferably completely, are removable. The smaller the hydraulic (second) diameter of the annular channel, the greater the heat transfer efficiency. The opposing flow resistance is low or even negligible with the usual dimensions compared to this effect with water or a water-antifreeze mixture as the coolant. Such a hydraulic diameter of the ring channel is, for example, less than 7 mm [seven millimeters], preferably less than 5 mm.

• - zumindest einen Zylinder mit einem Zylinderzentrum und mit einer Lauffläche für einen Kolben; und
• - zumindest einen Kühlmantel zum Kühlen der Lauffläche des Zylinders, wobei der Kühlmantel umfasst:
  • - zumindest einen Ringkanal, von welchem um das Zylinderzentrum ein Umlaufweg gebildet ist, und
  • - zumindest einen zu dem Ringkanal quer ausgerichteten Stichkanal mit einem Zentrumsbereich,
  wobei der Ringkanal im Betrieb mit Kühlmittel versorgbar ist, wobei der Ringkanal und der Stichkanal mittels einer Ausbuchtung miteinander verbunden sind, und wobei die Ausbuchtung in relativer Anordnung zu dem Stichkanal derart ausgeführt ist, dass zwischen:
  • - dem Zentrumsbereich des Stichkanals und
  • - einem Ringabschnitt des Ringkanals mit einem Umlaufabstand von mindestens 30° des Umlaufwegs zu dem Zentrumsbereich des Stichkanals eine freie Sichtlinie gebildet ist.

According to a further aspect, a crankcase for an internal combustion engine is proposed, comprising

• - At least one cylinder with a cylinder center and with a running surface for a piston; and
• - at least one cooling jacket for cooling the running surface of the cylinder, the cooling jacket comprising:
  • - at least one ring channel, from which a circulation path is formed around the center of the cylinder, and
  • - at least one branch channel aligned transversely to the ring channel with a central area,
  wherein the ring channel can be supplied with coolant during operation, wherein the ring channel and the branch channel are connected to one another by means of a bulge, and wherein the bulge is designed in relation to the branch channel in such a way that between:
  • - the central area of the branch canal and
  • - A clear line of sight is formed in a ring section of the ring channel with a circumferential distance of at least 30° of the circumferential path to the central region of the branch channel.

The main feature of the crankcase is that a transition channel is formed by the bulge between the branch channel and the ring channel,
wherein the transition fillet has a fillet radius equal to or less than three times the hydraulic diameter of the stub channel.

A transition valley is a smooth transition between the cross-section of the relevant branch canal and the cross-section of the annular canal. Such a smooth transition is preferably rounded, otherwise approximated to a rounding. Such a rounding has a fillet radius which is not necessarily constant. In a non-constant embodiment of the throat radius, the maximum section radius is referred to as the throat radius. The throat radius is very small according to this proposal, while at the same time due to the partial relative position of the branch channel to the ring channel, a low flow resistance and a free line of sight (for example, for a direct injection of a cleaning liquid) from the branch channel into the ring channel is made possible. As is generally defined, the hydraulic diameter is a theoretical subset circle of a cross-section of any shape, with the help of which the flow-mechanical behavior can be determined with the usual calculation models. In this case, for example, flow resistances and dead water zones caused by corners in the cross section are at least approximately taken into account.

• - zumindest einen Zylinder mit einem Zylinderzentrum mit einer Lauffläche für einen Kolben; und
• - zumindest einen Kühlmantel zum Kühlen der Lauffläche des Zylinders, wobei der Kühlmantel umfasst:
  • - zumindest einen Ringkanal mit einem hydraulischen Durchmesser, von welchem um das Zylinderzentrum ein Umlaufweg gebildet ist, und
  • - zumindest einen zu dem Ringkanal quer ausgerichteten Stichkanal mit einem Zentrumsbereich und mit jeweils einem hydraulischen Durchmesser,

wobei der Ringkanal im Betrieb mit Kühlmittel versorgbar ist, und wobei in den Zentrumsbereich des Stichkanals eine Reinigungsdüse mit zumindest einer in die Ebene des Ringkanals ausrichtbaren Düsenöffnung einführbar ist, und wobei:

• - der hydraulische Durchmesser des Ringkanals kleiner als 35% des hydraulischen Durchmessers des Stichkanals ist, und/oder
• - zwischen dem Stichkanal und dem Ringkanal von der Ausbuchtung eine Übergangskehle gebildet ist, wobei die Übergangskehle einen Kehlenradius aufweist, welcher gleich dem oder kleiner als dreimal der hydraulische Durchmesser des Stichkanals ist..

In other words, a crankcase for an internal combustion engine is proposed, comprising

• - At least one cylinder with a cylinder center with a running surface for a piston; and
• - at least one cooling jacket for cooling the running surface of the cylinder, the cooling jacket comprising:
  • - at least one annular channel with a hydraulic diameter, from which a circulation path is formed around the center of the cylinder, and
  • - at least one branch channel aligned transversely to the annular channel with a central area and each with a hydraulic diameter,

wherein the ring channel can be supplied with coolant during operation, and wherein a cleaning nozzle with at least one nozzle opening that can be aligned in the plane of the ring channel can be inserted into the central area of the branch channel, and wherein:

• - the hydraulic diameter of the annular canal is less than 35% of the hydraulic diameter of the branch canal, and/or
• - a transition groove is formed between the branch canal and the annular canal by the bulge, the transition groove having a groove radius which is equal to or less than three times the hydraulic diameter of the branch canal.

• - der betreffenden eingeführten Düsenöffnung und
• - einem Ringabschnitt des Ringkanals mit einem Umlaufabstand von mindestens 30° des Umlaufwegs zu der betreffenden eingeführten Düsenöffnung eine freie Sichtlinie gebildet ist.

At least one of the nozzle openings of a cleaning nozzle inserted into the central area of the branch channel can be aligned in the branch channel in such a way that between:

• - the nozzle orifice introduced in question and
• - A free line of sight is formed in a ring section of the ring channel with a circumferential distance of at least 30° of the circulation path to the relevant introduced nozzle opening.

The crankcase proposed here is, for example, (virtually) identical to the crankcase described above, with a bulge only preferably being formed. Reference is made to the definitions given above, insofar as they apply here, and the features and explanations given here apply at least to a preferred embodiment according to the preceding description.

In this embodiment of the crankcase, the center area of the branch duct is an area that is freely accessible from across, for example perpendicularly, to the plane of the ring duct and has such a sufficient cross section that a cleaning nozzle with at least one nozzle opening that can be aligned in the plane of the ring duct can be used without damage (and preferably without the required material-reducing rework of the puncture channel after demoulding from the mold) can be introduced. The central area is arranged within the stub channel, but not necessarily coaxially to a center of symmetry of the stub channel. In one embodiment, the central area is arranged on the annular channel side tangentially to a cross section or to a segment of the cross section of the annular channel. In one embodiment, the center region has a point of contact or intersection with the optional bulge.

As a result of the suitable arrangement of the central area relative to the branch channel in question, a clear line of sight is formed from there far into the ring channel, namely by at least a 30° circular path. In the case of a completely circumferential ring channel and a plurality of branch channels, the circumferential distance corresponds to slightly less than, exactly or more than half the respective circumferential distance between two branch channels, between which the relevant (part of) the ring channel(s) is arranged. For example, with four evenly distributed branch channels (for example arranged with a 90° circumferential spacing), the free line of sight in an advantageous embodiment extends up to, for example, a 40° circumferential path, or even a 50° circumferential path, or more. It should be noted that the start of the circulation path is defined here as the nozzle opening. In a view of the ring channel in a two-dimensional polar coordinate system, the ring section (or the end angle) to which the free line of sight is formed is, for example, at an absolute angle of 80° to 100° to a (any) reference line (for example an abscissa). and the nozzle opening at (a starting angle of) about 45° to 50° absolute. A cleaning liquid can thus be introduced from a nozzle opening of a cleaning nozzle (inserted into the branch duct) to such an extent that core residues of the (first) core of the annular duct can be reliably removed. One from the The cleaning fluid sprayed out from the nozzle opening can be introduced deep (along a circulation path) into the ring channel and, because of the low deflection of the nozzle jet, with little damped or undamped impulse. In one embodiment, as explained above, a rigid endoscope can be used with the advantages described above. This cleaning method is preferably so reliable that a follow-up check is not necessary. In a preferred embodiment, further measures for removing core residues from the ring channel are not necessary.

• - zumindest einen Zylinder mit einem Zylinderzentrum mit einer Lauffläche für einen Kolben; und
• - zumindest einen Kühlmantel zum Kühlen der Lauffläche des Zylinders, wobei der Kühlmantel umfasst:
  • - zumindest einen Ringkanal mit einem hydraulischen Durchmesser, von welchem um das Zylinderzentrum ein Umlaufweg gebildet ist, und
  • - eine Mehrzahl von zu dem Ringkanal quer ausgerichteten Stichkanälen mit jeweils einem Zentrumsbereich und mit jeweils einem hydraulischen Durchmesser,

wobei der Ringkanal im Betrieb mit Kühlmittel versorgbar ist, wobei der Ringkanal einen ersten Ringabschnitt aufweist, von welchem von einem ersten Startwinkel der relativen Lage eines ersten der Stichkanäle aus bis zu einem ersten Endwinkel bei einem Scheitelbereich des Ringkanals eine ringwärts gekrümmte Kurvenbahn gebildet ist,
wobei der Ringkanal einen zweiten Ringabschnitt aufweist, von welchem von einem zweiten Startwinkel der relativen Lage eines zweiten der Stichkanäle aus bis zu einem zweiten Endwinkel bei dem Scheitelbereich des Ringkanals ebenfalls eine ringwärts gekrümmte Kurvenbahn gebildet ist, und
wobei der erste Ringabschnitts und der zweiten Ringabschnitts mittels des Scheitelbereichs miteinander verbunden sind und wobei:

• - der hydraulische Durchmesser des Ringkanals kleiner als 35% des hydraulischen Durchmessers des Stichkanals ist, und/oder
• - zwischen dem Stichkanal und dem Ringkanal von der Ausbuchtung eine Übergangskehle gebildet ist, wobei die Übergangskehle einen Kehlenradius aufweist, welcher gleich dem oder kleiner als dreimal der hydraulische Durchmesser des Stichkanals ist.

In other words, a crankcase for an internal combustion engine is proposed, comprising

• - At least one cylinder with a cylinder center with a running surface for a piston; and
• - at least one cooling jacket for cooling the running surface of the cylinder, the cooling jacket comprising:
  • - at least one annular channel with a hydraulic diameter, from which a circulation path is formed around the center of the cylinder, and
  • - a plurality of branch channels aligned transversely to the ring channel, each with a central area and each with a hydraulic diameter,

wherein the annular duct can be supplied with coolant during operation, wherein the annular duct has a first annular section, from which an annularly curved curved path is formed from a first starting angle of the relative position of a first of the branch ducts to a first end angle at an apex area of the annular duct,
wherein the ring channel has a second ring section, from which a curved path likewise curved in the ring direction is formed from a second starting angle of the relative position of a second of the branch channels up to a second end angle at the apex area of the ring channel, and
wherein the first ring portion and the second ring portion are connected to each other by means of the apex region and wherein:

• - the hydraulic diameter of the annular canal is less than 35% of the hydraulic diameter of the branch canal, and/or
• - Between the branch channel and the ring channel, a transition groove is formed by the bulge, the transition groove having a groove radius which is equal to or less than three times the hydraulic diameter of the branch channel.

A clear line of sight is formed between the respective branch channel and the apex area of the respective annular section of the annular channel.

The crankcase proposed here is, for example, (virtually) identical to the crankcase described above, with a bulge only preferably being formed. Reference is made to the definitions given above, insofar as they apply here, and the features and explanations given here apply at least to a preferred embodiment according to the preceding description.

The circumferential distance formed, over which a free line of sight is formed, is dependent on the circumferential distance between the adjacent branch channels in the embodiment shown here. The revolving distance is thus possibly formed over a less than 30° revolving path. The necessary minimum circulation distance along the circulation path of the ring channel is also dependent on the nature and shape of the apex area. In one embodiment, the apex area is only a (theoretical) point in the circulation path of the annular channel. Then the respective lines of sight intersect at this point. In one embodiment, the apex area is a (theoretical) surface section (in the relevant plane) in the circulation path of the annular channel. The two lines of sight then do not have to intersect, or at least their straight lines do not have to intersect before this straight line intersects a wall of the ring channel. In one embodiment, at least one of the apex areas is adjoined by a supply line for the annular channel in question. For example, the surface area of the apex area is defined by a shape and the dimensions of the connection of the supply line to the ring channel in question.

The ring sections extend between a respective start angle and a respective end angle, which are related to the cylinder center of the tread. The ring sections form a curved path that is curved in the ring direction, with opposing curvatures and/or kinks being possible in the course of the curved path, insofar as these do not impair the free line of sight. In a preferred embodiment, such an annular curved path is aligned parallel to the area of the running surface of the cylinder that is to be cooled. A circumferential distance, as mentioned above, for example, is, for example, the difference between the start angle and the respective end angle of the relevant ring section. These angles are referenced to an (arbitrary) reference line (e.g. an abscissa of a two-dimensional coordinate system), the reference line passing through the center of the cylinder. For example, the Reference line when viewed from above (ie axially along the cylinder center) the abscissa of a two-dimensional or cylindrical polar coordinate system. In one embodiment, the starting angle is defined as a line that forms an intersection with the center of the cylinder and with the center of symmetry of the branch channel in question. In another embodiment, the starting angle is defined with respect to a line which intersects a point of intersection with the center of the cylinder and the cross section, preferably the center area as defined above, of the relevant branch channel. With a central area for accommodating a cleaning nozzle and/or an endoscope (see above), an intersection point with the respective nozzle opening or viewing opening is formed by said line of the starting angle. The line of the end angle makes a point of contact with or intersects the apex of the relevant ring section.

It is also proposed in an advantageous embodiment of a crankcase with at least two of the aforementioned characterizing features, with the cooling jacket preferably comprising at least one ring channel running completely around the center of the cylinder,
Four branch channels are particularly preferably provided and at least two of the branch channels, preferably the four, are connected to one another by means of the annular channel running completely around the center of the cylinder.

In a preferred embodiment, a cooling ring that is closed all the way around is formed by the at least one completely encircling ring channel, with which a large cooling surface and thus in turn a very good cooling capacity can be achieved. This creates long circulation paths, which can nevertheless be cleaned sufficiently well and inexpensively with the advantageous position of the branch channel relative to the ring channel proposed here.

In a preferred embodiment, four branch channels are assigned to at least one completely surrounding ring channel, preferably all ring channels. In this way, those circulation paths relevant for the cleaning method described here can be made short from each of the branch channels, for example if the branch channels are distributed evenly over the circumference of the cylinder, they can be limited to a maximum of 50° [fifty degrees], or even 40° or less. In one embodiment, in which a plurality of ring channels are arranged along the extension of a branch channel (compare the description below), it is not mandatory but merely preferred that each of the branch channels is connected via a common ring channel (preferably all ring channels).

• - einer radial-äußeren Wandung bei dem stichkanal-seitigen Einlass des Querschnitts des Ringkanals, und
• - einer radial-inneren Wandung mit einem Umlaufabstand zu dem Zentrumsbereich des Stichkanals von mindestens 30°, bevorzugt von 40°, des Umlaufwegs.

It is also proposed in an advantageous embodiment of the crankcase that the central area of the branch channel is arranged in the cross section of the branch channel in such a way that a jet line from the central area is aligned tangentially to:

• - a radially outer wall at the branch channel-side inlet of the cross-section of the annular channel, and
• - A radially inner wall with a peripheral distance from the center area of the branch channel of at least 30°, preferably 40°, of the peripheral path.

The annular channel has a cross section which is not necessarily constant. For example, the cross section at the (branch channel-side) inlet, which adjoins the branch channel, is widened, for example by means of the bulge or a transition groove (compare below). The cross section of the annular channel is in a radial plane through which the cylinder center in the cylinder extends transversely, that is to say intersecting, preferably perpendicularly, and is thus aligned transversely to the cross section of the branch channel. The tangential course of the beam line of the center area lies radially outside of the center area. The jet line of the central area runs tangentially insofar as it does not intersect the walls of the annular channel at least at the two points mentioned (at the inlet and at the circulation path mentioned) and over the entire course between the two points mentioned. The jet line originates at any (for example edge) point in the central area of the branch channel, for example in the case of a cleaning nozzle at the respective nozzle opening or in the case of an endoscope at the respective viewing opening. In an advantageous embodiment, the beam line corresponds to the previously defined line of sight.

In a preferred embodiment, the jet line of the center region not only has a mathematical cross-section of zero, but rather a small cross-sectional extent, with a radially outer side of the (volume-having) jet line of the center region being the radially outer Wall and a radially inner side of the (volume-having) beam line of the center region is tangent to the radially inner wall. The designations of the walls of the ring channel as radially outer wall and radially inner wall are also related to the center of the cylinder.

The central area is determined, for example, by the size of a cleaning nozzle, so that a jetting direction of a nozzle opening is aligned along the jet line of the central area tet can be directed directly into the ring channel. The central area is smaller than the cross section of the branch channel, so that in this embodiment a cleaning nozzle can be introduced into the relevant branch channel with play. In one embodiment, the center area is smaller by a maximum of 25% [twenty-five percent], preferably by a maximum of 10%, compared to a circular cross section of the puncture channel or a largest central area that can be placed in the cross section of the puncture channel. The branch channel can thus be designed with a small hydraulic diameter, ie with a small space requirement, while at the same time a (relatively large) cleaning nozzle can be inserted. And with this cleaning nozzle, a large ring section of the ring channel, namely at least 30° [thirty degrees of 360°], preferably at least 40° up to 50°, of the circular path of the ring channel (starting from the relevant branch channel without deflecting the jet) can be reached. In a preferred embodiment, a jet line, i.e. in this exemplary embodiment a nozzle jet (or at least its core jet) from a cleaning nozzle, reaches the entire annular section of the annular channel between the relevant branch channel and a supply line or up to the area which can be reached from another branch channel. for example an apex area of the relevant ring section.

It is further proposed in an advantageous embodiment of the crankcase that the cooling jacket comprises a plurality of annular ducts which are offset relative to one another along the extension of the cylinder.

In this embodiment, a plurality of annular ducts are arranged offset, preferably parallel, to one another along the extension of the cylinder, and thus preferably along the extension of the branch duct, for each cylinder. In one embodiment, the ring channels are at least partially interconnected (outside the branch channel). With the plurality of annular channels, a large cooling surface area is achieved on the running surface of the cylinder, while at the same time the flow volume is small and the heat transfer efficiency is high. In a preferred embodiment, some of the, preferably all, ring ducts are connected to one another by means of a common branch duct, preferably a plurality of branch ducts, with at least one common supply line being particularly preferably provided for some, preferably all, of the ring ducts.

In one embodiment, at least two of a plurality of annular ducts are connected to one another, preferably in a streamlined manner, outside of other line connections (such as, for example, a supply line and a branch duct).

In one embodiment, a supply line is provided between two branch channels, preferably approximately in the middle along the circulation path of the annular channels and/or preferably a total of two supply lines are provided.

• - ein Kurbelgehäuse nach einer Ausführungsform gemäß der obigen Beschreibung;
• - eine Kurbelwelle;
• - eine der Anzahl der Zylinder des Kurbelgehäuses entsprechende Anzahl von mit der Kurbelwelle kraftübertragend verbundenen und auf der Lauffläche des jeweiligen Zylinders bewegbaren Kolben; und
• - einen Zylinderkopf zum Verschließen des zumindest einen Zylinders und damit Bilden einer entsprechenden Anzahl von Zylinderräumen und zur Aufnahme einer Kraftstoffeingabeeinheit und einer Zündeinheit, sowie umfassend einen Lufteinlass und einen Abgasauslass.

According to a further aspect, an internal combustion engine is proposed, having at least the following components:

• - a crankcase according to an embodiment as described above;
• - a crankshaft;
• - A number of pistons, which corresponds to the number of cylinders in the crankcase and are connected in a force-transmitting manner to the crankshaft and can be moved on the running surface of the respective cylinder; and
• - A cylinder head for closing the at least one cylinder and thus forming a corresponding number of cylinder chambers and for accommodating a fuel input unit and an ignition unit, and comprising an air inlet and an exhaust gas outlet.

The internal combustion engine preferably has a conventional functional design and can be used as a substitute for a conventional internal combustion engine. The crankshaft absorbs the torque, which is delivered as a force from the piston to the crankshaft by means of the fuel ignition in the cylinder chamber. The cylinder chamber is closed on all sides, with a cylinder-axially movable wall of the cylinder chamber being correspondingly formed by the piston. Cylinder-axially above, ie facing away from the crankshaft, the cylinder chamber is closed off by the cylinder head, with the cylinder head having a plurality of openings that are closed or can be closed during operation for each cylinder. These openings are provided with valves for the air intake (possibly enriched with fuel in the carburetor in the case of an aspirated engine) and the exhaust gas outlet, which valves are controlled, for example, via a camshaft. Furthermore, openings are provided for an ignition unit, for example a spark plug, and optionally for a fuel input unit, for example an injection valve in a direct injection engine, these preferably being permanently sealed by the respective unit itself.

The internal combustion engine proposed here has a cooling structure for the cylinders with the same or better cooling capacity while at the same time lower production costs.

In one embodiment, the cylinder head also includes at least one feed line for coolant for the cooling jacket, with this at least one feed line preferably being connected to at least one branch duct.

According to a further aspect, a crankcase casting mold according to an embodiment as described above is proposed, wherein
the hollow shape of the at least one ring channel is maintained by a lost first core,
the hollow shape of the at least one branch channel preferably being maintained by a mounted, particularly preferably lost, second core.

The mold is configured to create the crankcase described herein. The mold forms the negative of the crankcase and thus the ring channel is formed as a positive, referred to here as a hollow mold. The same applies to the branch canal. Because the necessary orientation and shape of the ring channel is unsuitable for removing the positive (that is, the first core) again, this positive must be designed as a lost (first) core. The lost core is formed, for example, from pressed, glued and/or coated sand or salt. The lost core is inserted into the (preferably repeatedly usable, i.e. permanently usable) casting mold. During the casting process, a cavity (initially filled with the lost (first) core) is then formed there in accordance with the desired ring channel. This cavity will be released once the lost first core is destroyed and deployed. The material of the lost first core is preferably reusable for a new lost first core. Despite the disadvantageous post-processing step, with the casting mold proposed here and with the cleaning method proposed here (compare the previous and following description), the ring channel can be freed from core residues easily and inexpensively.

In an advantageous embodiment, the first core is held (preferably directly) by one, preferably a plurality of, second core(s), the second core being set up to form the desired cavity for the puncture channel in question. In a preferred embodiment, the second core of a branch channel is also a lost core.

1. a. in einen Stichkanal Eintauchen einer Reinigungsdüse mit zumindest einer Düsenöffnung zum Einspritzen von einer Reinigungsflüssigkeit; und
2. b. mittels Einspritzen von Reinigungsflüssigkeit aus der Reinigungsdüse, Ausspülen von Kernresten aus zumindest dem an den betreffenden Stichkanal angrenzenden 30°-Umlaufweg des zumindest einen Ringkanals, bevorzugt zugleich aller Ringkanäle zumindest eines Zylinders.

According to a further aspect, a cleaning method for a crankcase according to an embodiment according to the above description is proposed, which
is preferably cast by means of a mold according to an embodiment as described above, wherein the cleaning process exclusively comprises the following steps:

1. a. a cleaning nozzle with at least one nozzle opening for injecting a cleaning liquid is immersed in a branch channel; and
2. b. by injecting cleaning liquid from the cleaning nozzle, rinsing out core residues from at least the 30° circulation path of the at least one ring channel, preferably all ring channels of at least one cylinder, adjacent to the branch channel in question.

The cleaning method proposed here can be carried out in a particularly simple and cost-effective manner, with the cleaning method being carried out once for each or a smaller number of branch channels in one embodiment. In a preferred embodiment, a 100% test is not necessary, but a random test during quality assurance is sufficient.

In step a. a cleaning nozzle is immersed in the (preferably exactly straight) branch channel and thus the at least one nozzle opening, preferably two nozzle openings, is transferred relative to the at least one ring channel in the cylinder-axial height and in the angular position required for efficient flushing. Simultaneously with or subsequent to the immersion, a cleaning liquid is dispensed via the at least one nozzle opening and in step b. (after step a.) injected into the ring section in question (of the ring channel connected to the branch channel). In one embodiment, a multiplicity of ring channels is treated at the same time, for example the multiplicity of ring channels that are optionally arranged offset relative to one another in the cylinder-axial direction.

In a preferred embodiment, a cleaning nozzle is immersed into a plurality of branch channels at the same time and carries out step b. out, which means that flushing out, preferably via the supply line of the annular channel in question, is particularly efficient. In one embodiment, step b. carried out at least temporarily offset from one another by the cleaning nozzles that are immersed at the same time, so that the momentum of the nozzle jets directed in opposite directions does not mutually reduce.

• 1: eine Mehrzahl von Kühlmänteln eines Kurbelgehäuses in einer Draufsicht;
• 2: ein Ausschnitt einer Gussform für ein Kurbelgehäuse in einer schematischen Ansicht;
• 3: eine Schnittansicht eines Kurbelgehäuses in einer Verbrennungskraftmaschine mit einer Kurbelwelle; und
• 4: ein Flussdiagramm für ein Reinigungsverfahren.

The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, it being noted that the Drawings are not true to size and are not suitable for defining proportions. It is presented in

• 1 : a plurality of cooling jackets of a crankcase in a plan view;
• 2 : a section of a casting mold for a crankcase in a schematic view;
• 3 1: a sectional view of a crankcase in an internal combustion engine with a crankshaft; and
• 4 : a flowchart for a purification process.

In 1 a plurality of cooling jackets 7 of a crankcase 1 is shown in a plan view and therefore only one (e.g. uppermost, first) ring channel 8 is visible here (cf 2 or 3 ). The corresponding cylinder 3 with its running surface 5 radially inside the respective cooling jacket 7 is not shown here (cf 2 or 3 ), but the corresponding cylinder center 4. The first ring channel 8 is described here as representative of further ring channels 9,10. The three (here optionally identical) cooling jackets 7 are designed separately in this embodiment. Without excluding generality and purely for the sake of clarity, most of the reference numbers are only listed for one of the three cooling jackets 7 shown, but apply to each of the cooling jackets 7.

In this embodiment, each cooling jacket 7 comprises four branch channels 12, 13, which are connected to one (for example at least two) annular channel 8 of the cooling jacket 7 in a uniformly distributed manner. The branch channels 12,13 extend into the plane of the page (cf 2 or 3 ). Each of the branch channels 12,13 includes a central area 14 with a radius 46 which is smaller than half of the (first) diameter 33 of the branch channel 12,13. It should be pointed out at this point that the branch channels 12, 13 (and the supply lines 47) are here purely optionally circular in shape. Said first diameter 33 therefore relates to the hydraulic diameter, which is, for example, the same size as or slightly larger than the center area 14 . In this exemplary embodiment, the ring channel 8 can be supplied with coolant during operation via supply lines 47 . For example, according to the illustration, the upper supply line 47 is an inlet and the lower supply line 47 is an outlet for a coolant. For example, all or at least one of the branch channels 12,13 are set up as a through hole for screwing the crankcase 1 in an internal combustion engine 2.

In the embodiment shown, the cooling jacket 7 includes (optionally two) supply lines 47, which are each positioned centrally in the direction of circulation (relative to the cylinder center 4) between two branch channels 12,13 for the outflow (or inflow) of the coolant. The ring channel 8 has a cross section which is not necessarily constant. The cross section is expanded at the (branch channel-side) inlet 30, which adjoins the branch channel 12, 13, by means of a bulge 15 (here optionally formed as a transition channel 31). The transition groove 31 is a smooth transition between the cross section of the branch channel 12, 13 and the cross section of the ring channel 8. Such a smooth transition is rounded in this exemplary embodiment. Here the rounding has a throat radius 32 which is somewhat smaller than a (hydraulic) first diameter 33 of the branch channel 12,13.

In the case of the cooling jacket 7 shown on the right, a central area 14 is located in the upper right branch channel 12 according to the illustration. This central area 14 corresponds, for example, to a cleaning nozzle 19 (possibly of the same size) with (optional) two nozzle openings 20,21, from which cleaning liquid 45 can be injected into the connected annular sections 16,17. Furthermore, a central area 14 of the branch channel 13 there is shown at the bottom right, which also corresponds to a cleaning nozzle 19 with (optional) a single (first) nozzle opening 20, from which cleaning liquid 45 can in turn be injected into the first annular section 16. It can be seen from the intersection of the nozzle jets from the second nozzle opening 21 of the upper right cleaning nozzle 19 and from the first nozzle opening 20 of the lower right cleaning nozzle 19 that the two annular sections 16, 17, which are flow-connected to one another via a (common) apex area 26, with the relevant branch channels 12,13 introduced cleaning nozzles 19 can be reliably freed from core residues. In the upper right central area 14 (or the cleaning nozzle 19 there), the free line of sight 18 (or the jet line 27) is drawn in from this central area 14, which (optionally) runs approximately symmetrically in the middle of the jet of the second jet opening 21. This line of sight 18 touches a radially outer wall 28 (at the branch channel-side inlet 30) and a radially inner wall 29 (at the apex area 26) of the relevant (first) ring section 16 of the ring channel 8. In the embodiment shown (optional) the radially inner wall 29 from the relevant branch channel 12 only touches with a circumferential distance of about 30° circulation path 11 of the annular channel 8 . The first starting angle 22 and the second starting angle 23 are each defined for a possible nozzle opening 20,21 and referenced to reference line 48 (which is optional). These are about ±40° here. The first end angle 24 and the second end angle 25 are approximately ±10° in relation to the (any) reference line 48 shown. This results in the circumferential distance given above as the difference between the start angle 22.23 and the respective end angle 24.25. The remaining apex area 26 between the two end angles 24, 25 (preferably in the core area, corresponding to the jet line 27, without deflection) is reached by the jet of the jet, in any case with sufficient cleaning pressure to remove existing core residues.

In 2 1 is a section of a casting mold 42 for a crankcase 1 3 shown in a schematic view. It should be noted that the components here are named after the later functions of the crankcase 1. Rather, it is the formative (inverse) elements. In this exemplary embodiment, the casting mold 42 comprises three cylinders 3 each with a cylinder center 4 , which are designed as positive in the casting mold 42 , ie core, separately or in one piece with the rest of the casting mold 42 . In this exemplary embodiment, the cylinders 3 are each surrounded by a cooling jacket 7, which here (purely symbolically) comprises three annular channels 8, 9, 10 running axially offset from the cylinder (here optionally parallel). A positive, ie (first) core 43 for the ring channels 8 , 9 , 10 is to be kept in the mold 42 . The same applies to the branch channels 12,13, for each of which a (second) core 44 is provided. Each (first) core 43 of the annular channels 8,9,10 is held by the (second) cores 44 of the branch channels 12,13 and has a predefined (second) diameter 34. Because the necessary orientation and shape of the annular channels 8,9,10 are unsuitable for non-destructive retrieval of the (first) core 43, it must be designed as a lost core. The lost first core 43 is formed, for example, from pressed, glued and/or coated sand or salt. The material of the lost core 43 is to be removed (after the casting process) from the primary crankcase 1 so that coolant can flow unhindered through the ring channels 8,9,10 and a desired cooling capacity for the cylinders 3 can be achieved. In the embodiment shown, the (second) cores 44 of the branch channels 12, 13 can be removed without being destroyed. In one embodiment, the second cores 44 are also implemented as lost cores.

In 3 a purely schematic sectional view of a crankcase 1 in an internal combustion engine 2 with a crankshaft 35 is shown. In this exemplary embodiment, a section through the internal combustion engine 2 is shown, which includes the crankcase 1 here with (optionally three) cylinders 3 each with a cylinder center 4 . In this case, the pistons 6 in the respective cylinder 3 are shown in simplified form at the same height. According to the illustration, the crankshaft 35 is positioned below the cylinders 3 . The crankshaft 35 is connected in a force-transmitting manner to the pistons 6 , which move in the cylinders 3 within and guided by the respective running surface 5 of the respective cylinder 3 . The cooling jacket 7 with (here five) ring channels 8,9,10 (compare 2 ), integrally encloses the respective cylinder 3. The cooling jackets 7 are set up with the cylinders 3 for heat exchange (by means of a coolant conducted therein). The cooling jackets 7 can each be supplied with coolant via supply lines 47 (shown in broken lines). The cylinders 3 are closed at the upper end as shown by a cylinder head 36 and together with the pistons 6 enclose a cylinder chamber 37. The cylinder head 36 comprises at least one ignition unit 39 for each cylinder 3, an air inlet 40 (with valve) and an exhaust gas outlet 41 (with Valve). This exemplary embodiment is a direct-injection engine, that is to say with a (separate) fuel input unit 38 which is set up for injecting fuel under the (piston position-dependent) pressure into the cylinder chamber 37 . The required fresh air (possibly enriched with recirculated exhaust gas) can be fed into the cylinder chamber 37 via the air inlet 40 . The air-fuel mixture burned after ignition by means of the ignition unit 39 can be displaced out of the cylinder chamber 37 via the exhaust gas outlet 41 .

In 4 a flow chart for a cleaning process is shown. In step a. is a cleaning nozzle 19 after 1 immersed in the branch channel 12,13 and thus the at least one nozzle opening 20,21, preferably two nozzle openings 20,21, relative to the at least one ring channel 8,9,10 in the cylinder-axial height and in the angular position required for efficient flushing brought. Simultaneously with or subsequent to the immersion, a cleaning liquid 45 is dispensed at elevated pressure via the at least one nozzle opening 20,21.

In step b. (after step a.) is injected into the respective ring section 16,17 of the ring channel 8,9,10 connected to the branch channel 12,13. In one embodiment, a plurality of annular channels 8, 9, 10 are treated at the same time, for example the plurality of annular channels 8, 9, 10, which are optionally offset in relation to one another in the axial direction of the cylinder (cf 2 ). The ring sections 16, 17 are freed from core residues by means of the injection. Optionally, steps a. and b. (Step a′. or step b′.) repeated and/or carried out several times at the same time, correspondingly often, for example, in a wide range Ren cooling jacket 7 and / or at a next branch channel 12.13.

With the crankcase proposed here, a cleaning nozzle for removing material from a lost core can be placed in such a way that the cleaning liquid can penetrate deep into an annular channel and cleaning is thus simplified.

Reference List

1

crankcase

2

internal combustion engine

3

cylinder

4

cylinder center

5

tread

6

Pistons

7

cooling jacket

8th

first ring canal

9

second ring canal

10

third ring canal

11

circulation path of the ring canals

12

first branch canal

13

second branch channel

14

center area

15

bulge

16

first ring section

17

second ring section

18

line of sight

19

cleaning nozzle

20

first nozzle opening

21

second nozzle opening

22

first starting angle

23

second starting angle

24

first end angle

25

second end angle

26

crown area

27

beam line

28

radial-outer wall

29

radial inner wall

30

branch-side inlet

31

transition throat

32

throat radius

33

(first) diameter of the branch canal

34

(second) diameter of the annular canal

35

crankshaft

36

cylinder head

37

cylinder space

38

fuel input unit

39

ignition unit

40

air intake

41

exhaust outlet

42

mold

43

(first) core of the ring canals

44

(second) core of a branch canal

45

cleaning fluid

46

Radius of the center area

47

supply line

48

reference line (abscissa)

Claims (8)

Crankcase (1) for an internal combustion engine (2), having - at least one cylinder (3) with a cylinder center (4) and with a running surface (5) for a piston (6); and - at least one cooling jacket (7) for cooling the running surface (5) of the cylinder (3), the cooling jacket (7) comprising: - at least one annular channel (8,9,10) with a hydraulic diameter (34) of which a circulation path (11) is formed around the cylinder center (4), and - at least one branch duct (12,13) aligned transversely to the annular duct (8,9,10) and having a central area (14) and a hydraulic diameter (33) , Wherein the annular channel (8,9,10) can be supplied with coolant during operation, the annular channel (8,9,10) and the branch channel (12,13) being connected to one another by means of a bulge (15), and the hydraulic Diameter (34) of the annular channel (8,9,10) is less than 35% of the hydraulic diameter (33) of the branch channel (12,13), characterized in that the bulge (15) is arranged relative to the branch channel (12, 13) is designed such that between: - the central area (14) of the branch channel (12,13) and - a ring section (16,17) of the Rin g channel (8,9,10) with a circumferential distance of at least 30° of the circulation path (11) to the central region (14) of the branch channel (12,13) a free line of sight (18) is formed. Crankcase (1) for an internal combustion engine (2), having - at least one cylinder (3) with a cylinder center (4) and with a running surface (5) for a piston (6); and - at least one cooling jacket (7) for cooling the running surface (5) of the cylinder (3), the cooling jacket (7) comprising: - at least one annular channel (8,9,10), of which around the cylinder center (4). circulation path (11) is formed, and - at least one branch duct (12,13) aligned transversely to the annular duct (8,9,10) and having a central region (14), the annular duct (8,9,10) being operated with coolant can be supplied, the ring channel (8,9,10) and the branch channel (12,13) being connected to one another by means of a bulge (15), and the bulge (15) being arranged relative to the branch channel (12,13) in such a way it is designed that between: - the central area (14) of the branch channel (12,13) and - a ring section (16,17) of the ring channel (8,9,10) with a circumferential distance of at least 30° of the circulation path (11). A clear line of sight (18) is formed in the central area (14) of the branch channel (12,13), characterized in that between the branch channel (12,13) and the ring channel (8th ,9,10) a transition groove (31) is formed by the bulge (15), the transition groove (31) having a groove radius (32) which is equal to or less than three times the hydraulic diameter (33) of the branch channel (12, 13) is. Crankcase (1) according to at least one of the preceding claims, wherein the cooling jacket (7) comprises at least one annular duct (8,9,10) running completely around the cylinder center (4), four branch ducts (12,13) being particularly preferably provided and at least two of the, preferably four, branch channels (12,13) are connected to one another by means of the ring channel (8,9,10) running completely around the cylinder center (4). Crankcase (1) according to one of the preceding claims, wherein the central area (14) of the branch channel (12,13) is arranged in the cross section of the branch channel (12,13) in such a way that a jet line (27) from the central area (14) is tangential is aligned to: - a radially outer wall (28) at the branch channel-side inlet (30) of the cross section of the annular channel (8,9,10), and - A radially inner wall (29) with a peripheral distance from the central area (14) of the branch channel (12,13) of at least 30°, preferably 40°, of the peripheral path (11). Crankcase (1) according to one of the preceding claims, wherein the hydraulic diameter (34) of the ring channel (8,9,10) is less than 25% of the hydraulic diameter (33) of the branch channel (12,13). Internal combustion engine (2), having at least the following components: - A crankcase (1) according to any one of the preceding claims; - a crankshaft (35); - A number of pistons (6) which is connected to the crankshaft (35) in a force-transmitting manner and is movable on the running surface (5) of the respective cylinder (3) and which corresponds to the number of cylinders (3) of the crankcase (1); and - a cylinder head (36) for closing the at least one cylinder (3) and thus forming a corresponding number of cylinder chambers (37) and for accommodating a fuel input unit (38) and an ignition unit (39), and comprising an air inlet (40) and a exhaust outlet (41). Casting mold (42) for a crankcase (1) according to one of claim 1 until claim 5 , wherein the hollow shape of the at least one annular channel (8,9,10) is held by a lost first core (43), wherein the hollow shape of the at least one branch channel (12,13) is preferably held by a mounted, particularly preferably lost, second core ( 44) is held available. Cleaning method for a crankcase (1) according to one of claim 1 until claim 5 , Which preferably by means of a mold (42). claim 7 is cast, the cleaning process comprising only the following steps: a. a cleaning nozzle (19) having at least one nozzle opening (20, 21) for injecting a cleaning liquid (45) is immersed in a branch channel (12, 13); and b. by injecting cleaning liquid (45) from the cleaning nozzle (19), rinsing out core residues from at least the 30° circulation path (11) of the at least one ring channel (8,9,10) adjoining the relevant branch channel (12,13), preferably at the same time all ring channels (8,9,10) of at least one cylinder (3).

Images