JP2007278228A - Internal combustion engine - Google Patents

Abstract

An internal combustion engine capable of improving the oil discharging ability from an oil discharge hole even when the size of a piston is not changed.
An internal combustion engine includes a bottomed cylindrical piston 10, an oil ring groove 14 formed on an outer peripheral surface of the piston 10 and fitted with an oil ring 24, and one end portion of the oil ring groove 14 being opened. An oil drain hole 15 whose other end is opened on the inner wall of the piston 10 and a connecting rod 30 for drivingly connecting the piston 10 and the crankshaft 50 are provided. The internal combustion engine includes a pump 40 that is driven based on the relative displacement between the piston 10 and the connecting rod 30 and sucks oil discharged from the oil discharge hole 15.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine.

  A bottomed cylindrical piston is disposed in a cylinder of the internal combustion engine so as to be capable of reciprocating in the cylinder axial direction. FIG. 7 is a partial cross-sectional view of the internal combustion engine centered on the piston. As shown in FIG. 7, a first pressure ring groove 12, a second pressure ring groove 13, and an oil ring groove 14 are formed in order from the piston top surface 11 side on the outer peripheral surface of the piston 10. A first pressure ring 22 and a second pressure ring 23 are mounted in the first pressure ring groove 12 and the second pressure ring groove 13, respectively. These pressure rings (the first pressure ring 22 and the second pressure ring 23) have a function of performing an airtight seal between the outer peripheral surface of the piston 10 and the cylinder inner wall 1, and the air-fuel mixture, combustion gas, And the exhaust gas is prevented from leaking to the crankcase side.

  On the other hand, an oil ring 24 is mounted in the oil ring groove 14. The oil ring 24 has a function of supplying an appropriate amount of oil for lubrication to the pressure rings (the first pressure ring 22 and the second pressure ring 23) and scraping off excess oil remaining on the cylinder inner wall 1. And suppresses the oil from flowing into the combustion chamber. An oil drain hole 15 is formed in the oil ring groove 14, and an oil ring groove side opening 15 </ b> A that is one end of the oil drain hole 15 opens into the oil ring groove 14 and is the other end in the piston. A circumferential surface side opening 15 </ b> B opens in the inner wall of the piston 10. A part of the oil scraped off by the oil ring 24 flows out to the inner wall of the piston 10 through the oil ring groove 14 and the oil drain hole 15 and then drops to the oil pan in the crankcase.

  Incidentally, the diameter of the oil ring 24 and the width in the cylinder axial direction are set in accordance with the size of the piston 10. For this reason, the oil ring 24 and the oil ring groove 14 cannot be made larger than necessary, and accordingly, the size of the oil drain hole 15 is also limited. In addition, since such oil drain holes 15 need to be formed avoiding the portion of the piston boss 18 to which the piston pin 19 is attached, the number and formation positions thereof are also limited. For these reasons, in the conventional oil drain hole 15, the oil discharge capacity cannot be improved, and the oil that cannot be discharged stays in the oil ring groove 14. For this reason, the oil pressure in the oil ring groove 14 increases, and part of the oil leaks from between the oil ring 24, the oil ring groove 14, and the cylinder inner wall 1 and flows into the combustion chamber. As a result, not only the oil consumption increases, but the oil flowing into the combustion chamber may burn with the fuel, which may deteriorate the exhaust properties.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine capable of improving the oil discharging ability from the oil discharging hole even when the size of the piston is not changed. It is in.

Hereinafter, means for solving the above-described object and its operation and effects will be described.
According to the first aspect of the present invention, a bottomed cylindrical piston, an oil ring groove formed on an outer peripheral surface of the piston and fitted with an oil ring, one end portion of the oil ring groove being opened, and the piston In the internal combustion engine comprising an oil drain hole whose other end is opened on the inner wall of the cylinder and a connecting rod for drivingly connecting the piston and the crankshaft, the internal combustion engine is driven based on a relative displacement between the piston and the connecting rod, The gist of the invention is to provide a pump for sucking oil discharged from the oil holes.

  According to the above configuration, the pump is driven based on the relative displacement between the piston and the connecting rod and sucks oil from the oil drain hole. For this reason, even if the oil discharge capability of the oil discharge hole itself is low, the oil in the oil discharge hole is forcibly sucked by the pump. As a result, even when the size of the piston is not changed, the oil discharging ability from the oil discharging hole can be improved.

  Specifically, as described in claim 2, the pump includes a housing connected to one of the piston and the connecting rod, and a suction piston connected to the other of the pump and capable of reciprocating in the housing. Such a configuration can be adopted. According to this configuration, a pump driven based on the relative displacement between the piston and the connecting rod can be easily realized.

  According to a third aspect of the present invention, in the internal combustion engine according to the second aspect of the invention, the housing is centered on a connection portion between the piston and one of the connecting rods in a rotation plane on which the connecting rod rotates. The gist of the invention is that the suction piston is pivotably connected, and the suction piston is pivotally connected around the connecting portion between the piston and the other of the connecting rod in the rotation plane.

  According to the above configuration, the housing is connected so as to be rotatable around the connecting portion between the piston and one of the connecting rods in the rotating surface where the connecting rod rotates, and the suction piston is connected in the rotating surface. The piston and the connecting rod are connected so as to be rotatable around the connecting portion with the other. Thereby, the change in the inclination of the housing and the suction piston and the piston and the connecting rod of the internal combustion engine can be absorbed by the rotation of the connecting portion.

  According to a fourth aspect of the present invention, in the internal combustion engine according to the second or third aspect, the pump allows oil to flow from the oil drain hole into the housing and the oil drain hole from the housing. The gist of the present invention is that it includes a backflow control valve that suppresses the outflow of oil into the housing and a discharge valve that discharges oil inside the housing to the outside of the housing.

  According to the above configuration, the pump permits the oil flow from the oil drain hole to the inside of the housing and the back flow suppression valve that suppresses the oil flow from the inside of the housing to the oil drain hole and the oil inside the housing to be the same. And a discharge valve for discharging to the outside of the housing. For this reason, in the compression stroke of the suction piston, the oil in the housing can be prevented from returning again to the oil drain hole, and the sucked oil can be discharged to the outside of the housing.

The gist of the invention according to claim 5 is that, in the internal combustion engine according to claim 4, the exhaust valve is disposed at a position facing the top surface of the piston.
According to the above configuration, since the discharge valve is disposed at a position facing the top surface of the piston, oil discharged to the outside from the discharge valve is supplied to the piston top surface, and cooling of the piston top surface is performed. Performance can be improved.

<First Embodiment>
Hereinafter, a first embodiment of an internal combustion engine according to the present invention will be described with reference to FIGS. In the present embodiment, the same components as those of the conventional internal combustion engine described above are denoted by the same reference numerals, and the description thereof is omitted. Below, it demonstrates centering on difference with the conventional internal combustion engine.

FIG. 1 is a partial cross-sectional view of an internal combustion engine centered on a piston.
As shown in FIG. 1, the internal combustion engine includes a connecting rod 30 that drives and connects the piston 10 and the crankshaft 50.

The connecting rod 30 includes a connecting rod 31, a small end portion 32, and a large end portion 33.
A substantially cylindrical small end portion 32 is formed at one end of the connecting rod 31 on the piston 10 side. By connecting the central axis of the small end portion 32 and the central axis of the piston boss 18 and inserting the piston pin 19 into the small end portion 32 and the piston boss 18, the connecting rod 30 is moved to the piston. 10 is connected.

  A large end 33 having a substantially cylindrical shape and a larger diameter than the small end 32 is formed at the other end of the connecting rod 31 on the crankshaft 50 side. The large end portion 33 is divided into an upper large end portion 33A formed integrally with the connecting rod 31 and the small end portion 32, and a lower large end portion 33B forming other portions. The connecting portion of the crankshaft 50 is sandwiched between the inner peripheral surface of the upper large end portion 33A and the inner peripheral surface of the lower large end portion 33B, and the upper large end portion 33A and the lower large end portion 33B are connected to the bolt 34. The connecting rod 30 is connected to the crankshaft 50 by fastening with the nut 35.

  By being connected in this way, the piston 10 and the connecting rod 30 are displaced in accordance with the operation of the internal combustion engine. When the connecting rod 30 is viewed from the piston 10, the connecting rod 30 rotates around the piston pin 19. It will be displaced relatively by moving. Here, the rotation surface of the connecting rod 30 is the paper surface of FIG. 1 (hereinafter referred to as the rotation surface S). On the rotating surface S, the distance L between the inner peripheral surface of the piston skirt portion 16 that forms the skirt side portion of the piston 10 and the inner peripheral surface of the connecting rod 31 of the connecting rod 30 is determined by the operation of the internal combustion engine. As a result, it changes periodically.

  A pump 40 is disposed between the inner peripheral surface of the piston skirt portion 16 and the connecting rod 31. As will be described in detail below, the pump 40 is driven based on the relative displacement between the piston 10 and the connecting rod 30 and has a function of sucking oil discharged from the oil discharge hole 15.

FIG. 2 is a partial cross-sectional view of the internal combustion engine which is shown enlarged with the pump 40 as the center.
As shown in FIG. 2, the pump 40 includes a housing 41, a suction piston 42, and an introduction pipe 43.

  The housing 41 includes a bottomed cylindrical housing main body 41A and a first connecting shaft 41B. The housing main body 41A and the first connecting shaft 41B have their center axes positioned on the rotation surface S. It is arranged.

  In the housing main body 41A, one end of the first connecting shaft 41B is connected to the bottom surface (left surface in FIG. 2) facing the connecting rod 31. On the other hand, in the housing main body 41A, a through-hole 41C for enabling movement of a suction piston 42 described later in the housing main body 41A is formed on the bottom surface (the right surface in FIG. 2) facing the piston skirt portion 16. .

  In the housing main body 41A, an introduction hole 41D for introducing oil from the oil drain hole 15 into the housing main body 41A through an introduction pipe 43 described later passes through a portion facing the piston top surface 11 (upper portion in FIG. 2). Is formed. On the outer peripheral surface of the housing main body 41A, a lip-shaped introduction port 41E to which one end of the introduction pipe 43 is connected is formed around the introduction hole 41D. On the other hand, in the housing main body 41A, a portion (the lower portion in FIG. 2) facing the crankshaft 50 is formed with a discharge hole 41F for discharging oil from the inside of the housing main body 41A to the outside.

  A substantially annular first connection ring 41G is formed at the other end of the first connection shaft 41B. A portion of the connection rod 31 facing the housing body 41A (the right portion in FIG. 2) has a recess 36A and a first connection ring 41G. One connecting pin 36B is formed. Here, the axis of the first connecting pin 36B is perpendicular to the rotation surface S. When the first connection ring 41G engages with the first connection pin 36B, the first connection ring 41G, that is, the housing 41 including the first connection ring 41G can rotate about the first connection pin 36B on the rotation surface S. It has become. In the present embodiment, the first connecting ring 41G and the first connecting pin 36B constitute a connecting portion between the housing 41 and the connecting rod 30.

  The suction piston 42 includes a substantially disc-shaped piston main body 42A and a second connecting shaft 42B. The piston main body 42A and the second connecting shaft 42B have their center axes positioned on the rotation surface S. It is arranged like this.

  The piston main body 42A has an outer diameter slightly smaller than the inner diameter of the housing main body 41A, and is disposed in the housing main body 41A so as to reciprocate in the central axis direction. A pump chamber P is formed by the bottom surface (left surface in FIG. 2) on the connecting rod 30 side and the inner peripheral surface of the housing main body 41A in the piston main body 42A.

In the piston main body 42A, one end of the second coupling shaft 42B is connected to the bottom surface (the right surface in FIG. 1) on the piston skirt portion 16 side.
A substantially annular second connection ring 42F is formed at the other end of the second connection shaft 42B, and a recess 17A and a second connection pin 17B are formed in the inner portion of the piston skirt portion 16. Here, the axis of the second connecting pin 17B is perpendicular to the rotation surface S. Then, when the second connection ring 42F is engaged with the second connection pin 17B, the second connection ring 42F, that is, the suction piston 42 including the second connection ring 42F rotates around the second connection pin 17B on the rotation surface S. It is possible to move. In the present embodiment, the second connecting ring 42F and the second connecting pin 17B constitute a connecting portion between the suction piston 42 and the piston 10.

  The introduction pipe 43 is constituted by a so-called flexible tube that can bend flexibly when an external force acts on itself, and one end thereof is connected to the introduction port 41E. The other end of the introduction pipe 43 is connected to a lip-shaped oil discharge port 15 </ b> C that is formed around the piston inner peripheral surface side opening 15 </ b> B of the oil discharge hole 15.

  On the inner peripheral surface of the housing main body 41A, a backflow suppression valve 44 that switches the communication state between the introduction pipe 43 and the pump chamber P by opening and closing the introduction hole 41D is disposed. As the suction piston 42 moves, the backflow suppression valve 44 opens when the pressure in the pump chamber P becomes lower than the pressure in the introduction pipe 43, and the pressure in the pump chamber P becomes higher than the pressure in the introduction pipe 43. It is a pressure-sensitive valve that closes when high. The backflow suppression valve 44 has a function of allowing oil to flow into the pump chamber P from the oil drain hole 15 and suppressing oil outflow from the housing main body 41 </ b> A into the introduction pipe 43 and the oil drain hole 15.

  On the outer peripheral surface of the housing main body 41A, a discharge valve 45 that switches the communication state between the outside of the housing main body 41A and the pump chamber P by opening and closing the discharge hole 41F is disposed. The discharge valve 45 is opened when the pressure in the pump chamber P becomes higher than the pressure outside the housing body 41A as the suction piston 42 moves, and the pressure inside the pump chamber P is higher than the pressure outside the housing body 41A. It is a pressure-sensitive valve that closes when low. The discharge valve 45 has a function of discharging oil in the housing main body 41A to the outside of the housing main body 41A.

Next, the operation of the internal combustion engine of the present embodiment will be described with reference to FIG.
FIG. 3 is a partial cross-sectional view of the internal combustion engine which is shown enlarged with the pump 40 as the center. FIG. 3A shows the state of the internal combustion engine in the stroke in which the suction piston 42 moves in the direction in which the volume of the pump chamber P increases, that is, in the expansion stroke of the pump chamber P. FIG. These show the state of the internal combustion engine in the stroke in which the suction piston 42 moves in the direction in which the volume of the pump chamber P decreases, that is, the compression stroke in the pump chamber P.

  When the connecting rod 30 rotates in a direction away from the suction piston 42, the piston main body 42A is relatively displaced in the A direction with respect to the housing main body 41A as shown in FIG. As a result, the volume of the pump chamber P increases and the pressure in the pump chamber P decreases. At this time, when the pressure in the pump chamber P becomes lower than the pressure in the introduction pipe 43 and the oil drain hole 15, the backflow suppression valve 44 is changed from the closed state to the open state, and the oil inside the oil drain hole 15 is Is introduced into the pump chamber P through the introduction pipe 43. At this time, since the discharge valve 45 is closed, the introduced oil is stored in the pump chamber P.

On the other hand, when the connecting rod 30 rotates in a direction approaching the suction piston 42, the piston main body 42A moves in the B direction with respect to the housing main body 41A, as shown in FIG. As a result, the volume of the pump chamber P is reduced and the pressure in the pump chamber P is increased. At this time, since the backflow suppression valve 44 changes from the open state to the closed state, the oil inside the oil drain hole 15 is not introduced into the pump chamber P through the introduction pipe 43. At this time, since the discharge valve 45 is opened, the introduced oil is discharged to the outside of the pump chamber P, that is, to the oil pan in the crankcase.
<Effect of embodiment>
According to the embodiment described above, the following effects can be obtained.

  (1) A pump 40 that is driven based on the relative displacement between the piston 10 and the connecting rod 30 and sucks oil from the oil drain hole 15 is provided. For this reason, even if the oil discharge capability of the oil discharge hole 15 itself is low, the oil in the oil discharge hole 15 is forcibly sucked by the pump 40. As a result, even if the size of the piston 10 is not changed, the oil discharging ability from the oil discharging hole 15 can be improved.

  (2) The pump 40 includes a housing 41 that is connected to the connecting rod 30 and a suction piston 42 that is connected to the piston 10 and can reciprocate within the housing 41. According to this configuration, the pump 40 driven based on the relative displacement between the piston 10 and the connecting rod 30 can be easily realized.

  (3) The housing 41 is connected so as to be rotatable about a connecting portion with the connecting rod 30 in a rotating surface where the connecting rod 30 rotates, and the suction piston 42 is connected to the piston 10 within the rotating surface. It is connected so that rotation is possible centering on the connecting part. Thereby, the change in the inclination of the housing 41 and the suction piston 42 and the piston 10 and the connecting rod 30 of the internal combustion engine can be absorbed by the rotation of the connecting portions.

(4) The pump 40 permits the inflow of oil from the oil drain hole 15 into the housing 41 and suppresses the outflow of oil from the housing 41 to the oil drain hole 15. And a discharge valve 45 for discharging the oil to the outside of the housing 41. For this reason, in the compression stroke of the suction piston 42, it is possible to suppress the oil in the housing 41 from returning to the oil discharge hole 15 and to discharge the sucked oil to the outside of the housing 41.
Second Embodiment
Hereinafter, a second embodiment of an internal combustion engine according to the present invention will be described with reference to FIGS. 4 and 5. In the present embodiment, the housing body is different from the first embodiment in that a discharge hole is formed at a position facing the top surface of the piston.

Hereinafter, the difference from the first embodiment will be mainly described.
FIG. 4 is a partial cross-sectional view of the internal combustion engine, with the pump 140 being enlarged.
In the housing main body 141A, a portion facing the piston top surface 11 (upper portion in FIG. 4) is formed with a discharge hole 141F for discharging oil from the housing main body 141A to the outside.

  A discharge valve 145 that switches the communication state between the outside of the housing main body 141A and the pump chamber P by opening and closing the discharge hole 141F is disposed on the outer peripheral surface of the housing main body 141A. The discharge valve 145 has the same function as the discharge valve 45 in the first embodiment. Thereby, the discharge valve 145 discharges the oil in the housing main body 141A toward the outside of the housing main body 141A, that is, toward the piston top surface 11.

Next, the operation of the internal combustion engine of the present embodiment will be described with reference to FIG.
FIG. 5 is a partial cross-sectional view of the internal combustion engine, with the pump 140 centered. 5A shows the state of the internal combustion engine in the expansion stroke of the pump chamber P, and FIG. 3 (5) shows the state of the internal combustion engine in the compression stroke of the pump chamber P.

  When the connecting rod 30 rotates in a direction away from the suction piston 42, the piston main body 42A is relatively displaced in the A direction with respect to the housing main body 141A as shown in FIG. At this time, the backflow suppression valve 44 is changed from the closed state to the open state, and the oil inside the oil drainage hole 15 is introduced into the pump chamber P through the introduction pipe 43 as described in the first embodiment. is there. At this time, since the discharge valve 145 is closed, the introduced oil is stored in the pump chamber P.

On the other hand, when the connecting rod 30 rotates in a direction approaching the suction piston 42, the piston main body 42A moves in the B direction with respect to the housing main body 141A as shown in FIG. At this time, since the backflow suppression valve 44 is changed from the open state to the closed state, the oil in the oil drain hole 15 is not introduced into the pump chamber P through the introduction pipe 43 as described in the first embodiment. Just as you did. At this time, since the discharge valve 145 is opened, the introduced oil is discharged to the outside of the pump chamber P, that is, toward the piston top surface 11.
<Effect of embodiment>
According to the present embodiment described above, the following effects can be obtained in addition to the effects (1), (2), and (3) of the first embodiment.

  (1) Since the discharge valve 145 is disposed at a position facing the piston top surface 11, oil discharged to the outside from the discharge valve 145 is supplied to the piston top surface 11. Cooling performance can be improved.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the first embodiment, the discharge valve 45 is formed in a portion of the housing main body 41A that faces the crankshaft 50. In the second embodiment, the discharge valve 145 is formed in a portion of the housing main body 141A that faces the piston top surface 11. However, as long as the function of the suction piston 42 is not impaired, the position of the discharge valve may be arbitrarily changed. Moreover, oil can also be supplied with respect to the connection part of piston 10 and connecting rod 30 by changing the opening direction of a discharge valve. In this case, the oil supplied to the connecting portion acts as a lubricating oil, and the lubricating performance of the connecting portion can be improved.

  In the above embodiment, a pressure-sensitive type is adopted as the backflow control valve 44 that allows oil to flow from the oil drain hole 15 into the housing 41 and suppresses oil from flowing from the housing 41 to the oil drain hole 15. However, the backflow suppression valve may be arbitrarily changed as long as it has such a function. The same applies to the discharge valve 45 that discharges the oil inside the housing 41 to the outside of the housing 41.

  In the above embodiment, the housing 41 is connected to the connecting rod 30 and the suction piston 42 is connected to the piston. On the contrary, the housing is connected to the piston 10. The suction piston may be connected to the connecting rod 30.

  In the above embodiment, the pump is arranged only on one side of the connecting rod 30 on the rotation surface S, but the number of pumps is not limited to one. For example, as shown in FIG. 6, pumps 40 and 240 may be disposed on both sides of the connecting rod 30 on the rotation surface S.

  In the above embodiment, a reciprocating pump including a housing and a suction piston is employed, but the type of the pump of the present invention is not limited to such a reciprocating pump. For example, what is necessary is just to drive based on the relative angular displacement of the piston 10 and the connecting rod 30 and to suck the oil discharged from the oil drain hole 15.

1 is a partial cross-sectional view of an internal combustion engine according to a first embodiment of the present invention. The fragmentary sectional view centering on the pump concerning the embodiment. The fragmentary sectional view which shows the effect | action of the internal combustion engine concerning the embodiment. The fragmentary sectional view centering on the pump of the internal combustion engine concerning 2nd Embodiment of this invention. The fragmentary sectional view which shows the effect | action of the internal combustion engine concerning the embodiment. The fragmentary sectional view which shows the example of a change of the internal combustion engine of this invention. The fragmentary sectional view of the conventional internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder inner wall, 10 ... Piston, 11 ... Piston top surface, 12 ... 1st pressure ring groove, 13 ... 2nd pressure ring groove, 14 ... Oil ring groove, 15 ... Oil drain hole, 15A ... Oil ring groove side opening 15B: Piston inner peripheral surface side opening, 15C: Discharge port, 16 ... Piston skirt, 17B ... Second connecting pin, 18 ... Piston boss, 19 ... Piston pin, 22 ... First pressure ring, 23 ... First 2 pressure ring, 24 ... oil ring, 30 ... connecting rod, 31 ... connecting rod, 32 ... small end, large end 33, 33A ... upper large end, 33B ... lower large end, 34 ... bolt, 35 ... Nuts, 36A ... Recess, 36B ... First connecting pin, 40, 140, 240 ... Pump, 41 ... Housing, 41A, 141A ... Housing body, 41B ... First connecting shaft, 41C ... Through hole, 4 D ... Introduction hole, 41E ... Connection port, 41F, 141F ... Discharge hole, 41G ... First connection ring, 42 ... Suction piston, 42A ... Piston body, 42B ... Second connection shaft, 42C ... Second connection ring, 43 ... Introducing pipe, 44 ... backflow control valve, 45, 145 ... discharge valve, 50 ... crankshaft.

Claims (5)

A bottomed cylindrical piston, an oil ring groove formed on the outer peripheral surface of the piston and fitted with an oil ring, one end opening in the oil ring groove and the other end opening in the inner wall of the piston In an internal combustion engine comprising an oil drainage hole and a connecting rod for drivingly connecting the piston and the crankshaft,
An internal combustion engine comprising: a pump that is driven based on a relative displacement between the piston and the connecting rod and sucks oil discharged from the oil drain hole.   The internal combustion engine according to claim 1, wherein the pump includes a housing connected to one of the piston and the connecting rod, and a suction piston connected to the other of the pumps and capable of reciprocating in the housing. The internal combustion engine according to claim 2,
The housing is connected so as to be rotatable around a connecting portion between the piston and one of the connecting rods in a rotation surface in which the connecting rod rotates.
The internal combustion engine, wherein the suction piston is rotatably connected around a connecting portion between the piston and the other of the connecting rod in the rotation surface.   The pump allows a flow of oil from the oil drain hole into the housing and suppresses the oil from flowing from the housing into the oil drain hole. The internal combustion engine according to claim 2 or 3, comprising a discharge valve for discharging to the outside. The internal combustion engine according to claim 4,
The internal combustion engine, wherein the discharge valve is disposed at a position facing the top surface of the piston.

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