EP2325453B1 - Cooling system - Google Patents

Description

The invention relates to an internal combustion engine having the features of the preamble of claim 1, wherein the internal combustion engine has a coolant circuit which is divided into a cylinder block side coolant region and a cylinder head side coolant region. The cylinder-head-side coolant region may be divided into an outlet-side cooling region and an inlet-side cooling region, wherein a coolant flow in the respective coolant or coolant region is separately controllable.

The US 5,558,048 discloses an internal combustion engine having a coolant circuit split into a cylinder block side coolant region and a cylinder head side coolant region, the cylinder block having at least one cylinder block land in which a cooling slot is disposed, with a spout disposed in the cylinder head that communicates with the cylinder head side coolant region communicates. The cooling slot is circular. Also the summary of JP 5 141307 A discloses a cooling slot.

The EP 1 375 857 A discloses a cooling device for an internal combustion engine. The cooling device has a plurality of cooling cells in a cylinder head, which are separated from each other and can be traversed by a cooling liquid. The cooling device further comprises at least first and second means for controlling the flow rate, the means being connected to at least one first cooling cell of the cylinder head and to at least one second cooling cell of the cylinder head. The first and second means are capable of controlling the amount of cooling liquid flowing through each first cooling cell and every second cooling cell, respectively.

The DE 10 2005 033 338 A1 relates to an internal combustion engine having a cylinder housing with a plurality of juxtaposed cylinders and a cylinder head. The cylinder head closes off the cylinder housing on a cover surface, a cylinder head gasket being arranged between these two components. In each case, right and left of the row of cylinders, a first main liquid space is arranged, which is the cooling of the cylinder and the Coolant transport is used. Between the two sides of the first main liquid space a first cooling liquid gap is arranged at or near the top surface of the cylinder housing as a flow connection, which extends in a land area between two cylinders. By a second cooling liquid gap above the cylinder head gasket in the cylinder head, which is executed corresponding to the first cooling liquid gap and connected via at least one opening with this, the cooling in the region of the cylinder land and the cylinder head gasket should be substantially improved. Here, the second cooling liquid gap is in flow communication with a main liquid space in the cylinder head.

The EP 0 197 365 A2 discloses a device for the technical production of a cooling device of webs between adjacent, extremely closely cogged cylinders of a cylinder block of an internal combustion engine, the cylinder walls are surrounded on both longitudinal sides and end faces of the cylinder block of a cooling water jacket, with a core for forming the cooling water jacket. There are separate cores for the formation of cooling water channels provided in the webs, which bridge the height of the cylinder combustion chamber, the two opposite longitudinal sides of the sheath core and are either fitted at both ends or fixed in an upper sole core.

The EP 1 217 198 B1 is concerned with a cooling system for cooling a cylinder web, wherein at least one water channel extends exclusively on one side of a vertical axis through the center of the cylinder web.

It is known to allow the engine block and the cylinder head of the internal combustion engine to flow separately from each other with a coolant of a coolant circuit. In this way, the cylinder head, which is thermally coupled primarily by the combustion chamber and channel walls with the combustion air, and the engine block, which is thermally coupled above all with the friction points, can be cooled differently. By a so-called "split-cooling system" (separate coolant circuit) to be achieved that in the warm-up phase of the engine, the cylinder head is cooled, the engine block first not yet to be cooled, so that the engine block can be performed faster to the required operating temperature.

The EP 1 698 770 A1 deals with the split-cooling system, not only cylinder block and cylinder head are controlled separately by coolant technology, but also the cylinder head is divided into separate cooling areas. This is advantageous in that a well controllable and optimized heat balance, in particular of the cylinder head, is achieved, the warm-up behavior of the internal combustion engine being decisively improved.

The invention has for its object to provide an internal combustion engine of the type mentioned above, the cooling or warm-up behavior is further improved by simple means.

According to the invention the object is achieved by an internal combustion engine having the features of claim 1.

It is advantageous if in the at least one cylinder block web of the cylinder block, a cooling slot is arranged, wherein in the cylinder head a crossing is arranged and, wherein in the cylinder head an outlet is arranged, which is in communication with the cylinder head side coolant area, wherein the block water jacket on the passage with the Cooling slot is in communication, which is in communication with the outlet and, wherein coolant from the block water jacket over the passage into the cooling slot and from here via the outlet in the cylinder head side coolant region is feasible.

In a favorable embodiment, it can be provided that the cylinder-head-side coolant area is divided into an outlet-side cooling area and an inlet-side cooling area, wherein coolant from the inlet-side cooling area can be guided into an outlet housing, in which the outlet-side cooling area opens.

The invention is based on the finding that the split-colling system can be improved to the extent that the cooling system is not only divided into a cylinder block area and a cylinder head area, but the Cylinder head is further divided into an outlet-side cooling region and an inlet-side cooling region. Using skilful cooling strategy so different areas of the engine, especially in its warm-up phase can be controlled by controls. For example, a coolant flow in a first phase has a magnitude of zero, wherein in a second phase, the outlet side of the cylinder head is cooled. Only in a third phase of the cylinder block is cooled. This has proved to be practical in that the internal combustion engine can be led to the required operating temperature as quickly as possible.

Usually, the coolant flow through the cylinder block is controlled by means of a block thermostat. But flows z. B. during the warm-up phase, no coolant through the cylinder block, because the block thermostat is closed, the resulting heat, such as frictional heat, which is not dissipated, a warming example of lubricant, which is indeed desirable to improve the warm-up properties. However, the coolant can be warmed up in such a way that vapor or air bubbles form, which collect in the upper area of the cylinder block, and displace the coolant actually present there. Between the liners of the cylinder, the so-called cylinder web or cylinder block web is arranged, which separates adjacent liners from each other. For better cooling this is provided with a hole or a slot, wherein the slot is connected directly to the block water jacket. The vapor bubbles displace the coolant now just in this cooler within the web. This can cause temperature-related damage, so that the block thermostat must be opened to prevent displacement of the coolant in the upper area by replacing the coolant. With the solution according to the invention, however, it is possible to keep the block thermostat, especially in the warm-up phase of the internal combustion engine longer closed because the resulting vapor bubbles can be derived from the upper region of the cylinder block. This is advantageously achieved in that the cylinder-head-side coolant region, preferably its inlet-side cooling region is coupled to the block water jacket; because the block water jacket is about the transition in the cylinder head, the cooling slot in the cylinder web and the crossing seen in cross-section opposite arranged outlet in Cylinder head indirectly in connection with the cylinder-head side coolant region, or preferably with the inlet-side cooling region, so that a derivation of the vapor bubbles in the cylinder head can be reached, even if the block thermostat is closed. The resulting vapor bubbles are thus transported into the cylinder head, in particular in the inlet-side cooling region.

Another advantage of the invention lies in the fact that when the block thermostat is open a significantly improved cooling of the cylinder web is achievable. In this case, the coolant follows the previously described path from the block water jacket, via the crossing, the cooling slot and the outlet in the cylinder-head-side coolant region or its inlet-side cooling region. In this case, the coolant cools the cylinder head or preferably the inlet side of the cylinder head, and enters an outlet housing without having previously in contact with the coolant jacket of the outlet-side cooling region.

The coolant for cooling the outlet side flows through z. B. the upper and lower shell of the outlet side cooling region and then also enters the outlet housing, in which mixes the coolant flow from the inlet-side cooling region and from the outlet-side cooling region.

In this respect, it is advantageously provided that the block thermostat controls the coolant flow through the cylinder block, wherein the coolant flow is divided before the block thermostat at least in a partial flow, which enters the outlet side cooling region of the cylinder head side coolant region.

In a further advantageous embodiment of the block thermostat is integrated with its housing in the cylinder block, but can also be designed as a separate component. Thus, a coolant pump output is advantageously connected directly to the cylinder block. But also the outlet side or the outlet-side cooling area is connected directly to the pump outlet. Furthermore, a turbocharger can also be connected directly to the coolant pump.

Conveniently, the cooling slot is not directly, but indirectly connected via the passage with the block water jacket, the passage is carried out in a preferred embodiment quasi slot-like.

Between the cylinder head and the cylinder block, a cylinder head gasket is arranged, which advantageously has in the region of the crossing inlet and outlet openings, wherein the inlet opening is associated with the block water jacket or a corresponding mouth opening of the block water jacket, and the outlet opening of the cooling slot. Of course, it is within the meaning of the invention to provide the cylinder head gasket with an opening corresponding to the passage. Of course, also the cross-section arranged opposite to the passage arranged outlet associated with a corresponding opening in the cylinder head gasket.

In this respect, it is advantageously provided that the coolant enters the transition from the block water jacket from bottom to top through the cylinder head gasket, flows along the passage in the cylinder head in the direction of the cooling slot, and flows through the cylinder head gasket from top to bottom into the cooling slot. In the cooling slot, the coolant preferably flows from the passage in cross section along the cylinder block web toward the outlet, and there again from bottom to top through the cylinder head gasket into the outlet, ie into the cylinder head or into the cylinder head side coolant area.

It is expedient for the purposes of the invention that the block-side coolant region comprises web cooling channels, which are introduced into the cylinder block web, and which are preferably in communication with the block water jacket, wherein the web cooling channels are designed to taper in the direction of the cylinder head, so that balconies on the cylinder block web are formed, which are oriented towards screw pipes.

Advantageously, the web cooling channels have a first section and at least one second section, the second section, with respect to the first section, continuously tapering in its cross section except for a remaining cross section, the second section preferably tapering eccentrically. This means that the respective web cooling channel with an inner side, which is oriented in cross-section to the central axis of the cylinder block web, running in its second portion of this running away oriented, with the opposite side of the web cooling channel in both the first section and in the second section preferred runs parallel to the central axis of the web cooling channel. The web cooling channels can be designed in their second section so that the balconies are locally associated with screw pipes.

Favorable in the context of the invention is when one of the web cooling channels arranged on both sides of the central axis opens with its second section in the passage.

Another advantage of the invention is to be seen in the advantage that the coolant can be brought as close as possible to the critical thermal web portion, while in an upper region, or seen in cross-section laterally of the cylinder block web, the balconies are formed. In this respect, it is quite advantageous to make the cooling slot seen in cross-section circular section, each seen in cross section to the left and right of the quasi-circular cooling slot a security area or the balconies are formed or remain. Advantageously, optimum cooling is thus achieved both in the upper region of the cooling slot and in the lower region of the cooling slot (near cooling water). By pulling in at the bottom, the material requirements of the cylinder block are reduced, which simultaneously reduces weight and costs.

Advantageously, therefore, the cooling slot is arranged in the cylinder block web, which is covered opposite to its slot bottom of the cylinder head gasket. It is within the meaning of the invention to pour in the transition, the cooling slot, and / or the outlet either with production of the respective components, or to introduce them mechanically separately. For example, the cooling slot can be achieved by simple mechanical milling z. B. generated by means of a disc milling cutter. It is also conceivable to reduce the radius of the side milling cutter and to carry out a horizontal movement along the planned cooling slot after vertical retraction. It is also possible to use a suitable pin milling cutter instead of the side milling cutter.

The cooling slot thus has a slot opening with slot walls and the slot bottom. The slot opening is covered by the cylinder head gasket, wherein preferably each adapted to the transition and the outlet openings may be provided in the cylinder head gasket. The opposing slot walls are spaced apart from each other with the slot width and pass into the slot bottom in each case.

According to the invention it is provided that the bottom of the slot is rounded with a radius which is smaller than the slot width. In a preferred embodiment, the radius has an amount which corresponds to half the slot width. In a further preferred embodiment, the radius has an amount which corresponds to up to a quarter of the slot width. Conveniently, the cooling slot is in this case carried out with a slot tool, which has a "tip" with a correspondingly large rounding. Of course, it is possible to perform the slot bottom instead of the circular configuration parabolic. With the advantageous embodiment of the slot base a harmonious transition of the slot walls is achieved to the slot bottom, which causes a reduction of voltage peaks in the cylinder block and an increase in the component load capacity. The cooling slot is designed in a transverse direction of the internal combustion engine analogous to the embodiment in the longitudinal direction described above. This means that as large a radius as possible is selected for the geometry of the cooling slot, which is limited only by the slot width and the slot depth.

• Verringerung der Bohrungsverzüge
• Geringere Kosten, geringeres Gewicht, geringere Bauteilbelastung, geringere
• Klopfneigung, geringerer Kraftstoffverbrauch,
• geringere Ölalterung/Verkokungen,
• Entlastung der Zylinderkopfdichtung
• einfache Herstellung
• Verbesserte Kühlung in kritischen Bauteilbereichen durch Vergrößerung der Wärme abführenden Oberfläche, bzw. kurze Wärmeleitwege
• Verbesserte Kühlung hinsichtlich der Gefahr des Ablösens von Büchse und
• Wand insbesondere bei Aluminiumblöcken, wobei bei Graugußbüchsen eine Verminderung der Gefahr des Büchsenabsinkens und ein Versagen der Kopfdichtung reduziert ist.

Furthermore, the invention advantageously achieves the following advantages, for example:

• Reduction of the bore distortion
• Lower costs, lower weight, lower component load, lower
• Knock tendency, lower fuel consumption,
• lower oil aging / coking,
• Relief of the cylinder head gasket
• simple production
• Improved cooling in critical component areas by enlarging the heat dissipating surface, or short heat conduction paths
• Improved cooling with regard to the risk of detaching the sleeve and
• Wall in particular aluminum blocks, with gray cast iron bushes a reduction in the risk of rivet sinking and failure of the head gasket is reduced.

Fig. 1

einen beispielhaften Kühlmittelkreislauf eines Verbrennungsmotors,

Fig. 2

einen Querschnitt durch den Verbrennungsmotor aus Figur 1,

Fig. 3

eine Ansicht auf eine Zylinderkopfdichtung von unten,

Fig. 4

einen Längsschnitt durch einen Zylinderblock und einen erfindungsgemäßen Kühlschlitz, und

Fig. 5

den Kühlschlitz aus Figur 4 als Einzelheit.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. Show it:

Fig. 1

an exemplary coolant circuit of an internal combustion engine,

Fig. 2

a cross section through the internal combustion engine FIG. 1 .

Fig. 3

a view of a cylinder head gasket from below,

Fig. 4

a longitudinal section through a cylinder block and a cooling slot according to the invention, and

Fig. 5

the cooling slot FIG. 4 as a detail.

In the different figures, the same parts are always provided with the same reference numerals, so that these are usually described only once.

FIG. 1 shows an internal combustion engine 1, which has a coolant circuit 2. The coolant circuit 2 is divided into a cylinder block-side coolant region 3 or cylinder block water jacket and into a cylinder head-side coolant region 4 or headwater jacket, so that a split-cooling system is formed. The cylinder-head-side coolant area 4 is further divided by way of example into an outlet-side cooling area 6 and an inlet-side cooling area 7, which of course is not intended to be limiting, wherein a coolant flow in the respective cooling or coolant area 2, 3, 4, 6, 7 is separately controllable , The in FIG. 1 Coolant circuit 2 shown by way of example will be described in more detail below.

As FIG. 2 shows, in at least one cylinder block web 8 and in a cylinder web 8 of the cylinder block 45, a cooling slot 9 is arranged, wherein in the cylinder head 44 a passage 11 is arranged. Further, an outlet 12 is arranged in the cylinder head 44, which is in communication with the cylinder-head-side coolant region 4 or preferably with the inlet-side cooling region 7. The block water jacket, or the cylinder block-side coolant area 3 is indirectly connected via the passage 11 with the cooling slot 9, wherein the cooling slot 9 is in communication with the outlet 12. The outlet 12 is arranged opposite to the passage 11 in the cross section shown. The coolant is thus from the block water jacket or the cylinder block side coolant region 3 via the passage 11 in the cooling slot 9, along the cylinder block web 8 toward the outlet 12, and from here via the outlet 12 in the cylinder head side coolant region 4 and in the inlet side cooling region 7 feasible. In this respect, the block water jacket is coupled via the transition 11 and the cooling slot 9 with the cylinder head side coolant region 4 and the inlet-side cooling region 7, or indirectly connected. In a preferred embodiment of the block water jacket is connected to a web cooling channel 57 in connection, the advantageous embodiment will be described in more detail below.

First, the coolant circuit 2 according to FIG. 1 a coolant pump 13. In the cylinder block, a block thermostat 14 is integrated, wherein before the block thermostat 14, for example, two branches 16,17 are arranged. The block thermostat 14 is z. B. executed as a wax element, which allows the coolant flow to pass only in one direction, so that a backflow of the coolant is avoided in the closed or open block thermostat in the direction of the coolant pump 13. One of the branches 16 is directly connected to a turbocharger 18, wherein an output connection 19 of the turbocharger 18 opens into a connecting line 21, which opens into a surge tank 22. The connecting line 21 is shown in dotted, and is based on a thermostat 22. However, the output connection 19 of the turbocharger 18 can also be connected directly to a coolant pump inlet 23 or a coolant return 24.

The other branch 17 is connected to the outlet side cooling portion 6 of the cylinder head.

The block thermostat 14 is meaningfully required for the split-cooling system. The coolant which passes through this block thermostat 14 (arrow 26) flows through the cylinder block-side cooling region 3, enters the cylinder head, in particular the inlet-side cooling region 7, flows through the inlet-side cooling region 7, cools the inlet side 27 of the internal combustion engine 1 and passes without previously having contact with the coolant flowing in the outlet-side cooling region 6, into an outlet housing 28 (arrow 29). The coolant for cooling the outlet side 31 of the cylinder head flows through the outlet-side cooling region 6 and also enters the outlet housing 28 (arrow 32). In the outlet housing 28, both coolant streams are mixed in front of the thermostat 22. A return of the coolant can then take place, for example via a vent valve 34, an EGR cooler 36, a cabin heater 37, an oil heat exchanger 38 and main cooler 39 back to the coolant pump 13. Of course, this return should only be exemplary, with a different order or bypass lines as in FIG. 1 shown are conceivable.

For example, the thermostat 22 may also be connected, as shown, to the main radiator 39, which is connected to the coolant pump inlet 23 via a connecting line 41. It is also possible to connect the thermostat 22 via a bypass 42 with the coolant pump inlet 23. As shown, the oil heat exchanger 38 also opens into the coolant pump inlet 23. Dotted is a connection 43 from the main cooler 39 to the expansion tank 22. The thermostat 22 can be electrically controlled, or z. B. be executed as a map thermostat.

As shown, the housing of the block thermostat 14 is integrated in the cylinder block. The block thermostat 14 can also be designed as a separate component. Advantageously, the coolant pump outlet is connected directly to the cylinder block or to the cylinder block-side coolant region 3. Also, the line for supplying the exhaust side 31 of the cylinder head and also the turbocharger 18 (branch 16, 17) is connected directly to the Kühlmittepumpenaustritt. The By contrast, outlet housing 28 is exemplified as a separate component, but may still have an EGR valve with appropriate lines to supply the EGR cooler.

In particular, in a warm-up phase of the internal combustion engine 1, the block thermostat 14 can remain closed longer, since possibly forming vapor or air bubbles from the cylinder block or its upper portion via the previously described path crossing 11, cooling slot 9 and outlet 12 in the cylinder head or can be derived in the inlet-side cooling region 7. Thus, a warm-up behavior of the internal combustion engine is decidedly improved because the block thermostat 14 must be opened only when an exchange of the coolant in the cylinder block side coolant area 3 or in the water jacket is actually required.

Again FIG. 2 can be seen further, the cooling slot 9 is not directly, but indirectly connected via the passage 11 with the cylinder block side coolant area 3. The passage 11 is quasi slot-like executed.

Between the cylinder head 44 and the cylinder block 45, a cylinder head gasket 46 is arranged, which advantageously has an opening 47 adapted to the passage 11, which, as shown, has a corresponding longitudinal extent corresponding to the slot-like configuration ( FIG. 3 ). Of course, a corresponding to the outlet 12 running opening 48 opposite to the opening 47 in the cylinder head gasket 46 is provided.

In this respect, the cooling slot 9 is advantageously introduced into the cylinder block web 8 in such a way that it has no direct connection to the block water jacket or the cylinder block side coolant region 3 in the cylinder block 45. Thus, a safety area 49 or balcony 50 is advantageously formed in the transverse direction of the cooling slot 9 on both sides of the cooling slot 9. This can be performed optimally each casting technology, and should, if the cooling slot 9 is mechanically introduced, not be injured.

The coolant guide thus takes place from the block water jacket or from the cylinder block side coolant region 3 from bottom to top through the cylinder head gasket 46 through the opening 47 in the passage 11. The coolant flows along the transition 11 and from there through the opening 47 from top to bottom through the Cylinder head gasket 46 in the cooling slot 11, along this towards the outlet 12 and there again from bottom to top through the opening 48 in the cylinder head gasket 46 in the outlet 12, which is in communication with the cylinder head side cooling region 4 and with the inlet side cooling region 7 , As in FIG. 2 Of course, it is within the meaning of the invention that both (cooling slot 9/11 crossing) do not necessarily have to be aligned, but still a coolant guide in the context of the invention is possible.

Again FIG. 2 can be seen further, in each case on both sides of the cylinder block web 8, based on its central axis X, a web cooling channel 57 is arranged, which, as described above with the block water jacket in combination. The respective web cooling channel 57 has two sections 58 and 59 in the illustrated drawing plane. The first section 58 extends in the illustrated plane of the drawing from bottom to top and merges into the second section 59, which is oriented in the direction of the cylinder head. The second section 59 is preferably designed to be eccentrically tapered in the illustrated embodiment, so that in each case the balconies 50 are formed on both sides of the central axis X. In the illustrated embodiment, the second portion 59 of the right in the plane of the web cooling channel 57 is guided so that it opens into the passage 11 (through the seal opening 47). The opposite second section 59 of the left in the plane of the web web cooling channel 57 is preferably guided in the direction of the cylinder head gasket 46, or covered by this.

The cooling slot 9 can be cast in the manufacture of the cylinder block 45 with. But it is also possible a mechanical introduction, as already indicated above. In the mechanical introduction of the cooling slot 9, a side milling cutter can be used, so that the cooling slot 9 is generated by simply vertical retraction. It is also conceivable, the radius of the To reduce the side milling cutter, and perform a horizontal movement along the planned cooling slot 9 after vertical retraction. Of course, a suitable pin milling cutter can be used instead of the disc milling cutter.

Again FIG. 2 can be seen, the cooling slot 9 is seen in cross-section preferably designed circular section. Advantageously, an optimal cooling of the cylinder block web 8 area of the cooling slot 9 is achieved with the illustrated embodiment. By pulling in the lower area of the material requirement of the cylinder block 45 is additionally reduced, which at the same weight and cost are reduced.

In the cylinder head 44 and in the cylinder block 45 screw pipes 51 are provided. It is possible to design the web cooling channels 57 so that the balconies 50 have local contact with the screw pipes 51.

In FIG. 5 the cooling slot 9 is off FIG. 4 as a detail in a longitudinal section, of course not shown to scale. The cooling slot 9 has a slot opening 52 with slot walls 53 and a slot bottom 54. Opposite the slot bottom 54 of the cooling slot 9 is covered by the cylinder head gasket 46, wherein in the cylinder head gasket 46 preferably the openings 47 and 48 are arranged. The opposing slot walls 53 are spaced apart from each other with the slot width 56 and pass into the slot base 54 in each case.

According to the invention, it is provided that the slot base 54 is made rounded with a radius whose magnitude is smaller than the slot width 56. In a preferred embodiment, the radius has an amount which corresponds to half the slot width 56. In a further preferred embodiment, the radius has an amount which corresponds to up to a quarter of the slot width 56. Conveniently, the cooling slot 9 is in this case carried out with a slot tool, which has a "tip" with a correspondingly large rounding. The cooling slot 9 is in a cross section of the internal combustion engine ( FIG. 2 ) executed analogously to the embodiment in the longitudinal section described above. That means, that for the geometry of the cooling slot 9 as large a radius as possible is selected, which is limited only by the slot width 56 and the slot depth.

Claims (3)

1. Internal combustion engine, which has a coolant circuit (2) which is divided into a cylinder block-side coolant region (3) and a cylinder head-side coolant region (4), the cylinder block having at least one cylinder block web (8), in which a cooling slot (9) is arranged, which is covered, opposite to its slot bottom (54), by a cylinder head gasket (46), characterized in that the cooling slot (9) has at its slot bottom (54) a radius, the amount of which is smaller than its slot width (56).
2. Internal combustion engine according to Claim 1,
   characterized in that
   the cooling slot (9) is cast in the cylinder block web (8) and/or is introduced mechanically into the cylinder block web (8).
3. Internal combustion engine according to Claim 1 or 2,
   characterized in that
   the cooling slot (9) is designed in the manner of a segment of a circle, as seen in cross section, so that safety regions (49) are formed in each case laterally with respect to the cooling slot (9).

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