JP2008255816A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a smooth flow of fluid between the inside of a cylinder head and a crank chamber even when an internal combustion engine is inclined so that a cylinder axial line of the internal combustion engine is inclined around a cylinder row direction. <P>SOLUTION: This internal combustion engine 10 comprises communication paths 60, 80 communicating the inside of a cylinder head 26 with a crank chamber 58, and a wall 76 dividing a space of the crank chamber 58 nearer the cylinder head 26 than a journal of a crank shaft 66 into areas corresponding to cylinders. The engine has an intermediate passage 88 formed on the wall 76 to communicate with the two different communication paths 60, 80 communicated with the crank chamber 58. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine that includes a communication passage that communicates the inside of a cylinder head and a crank chamber, and through which a fluid such as air, blowby gas, or oil flows.

  Patent Document 1 discloses a cylinder block that improves the return of oil in the cylinder head into the crankcase when the cylinder row of the internal combustion engine is tilted in the vertical direction. This cylinder block has a plurality of cylinders arranged in a row, and in this cylinder block, a plurality of oil dropping holes penetrating the cylinder block in the vertical direction are provided in the vicinity of one side surface of the cylinder block in the cylinder row direction. . A passage extending in the cylinder row direction is provided in the vicinity of the one side surface of the cylinder block so that the plurality of oil dropping holes communicate with each other.

JP 2004-190524 A

  In general, a vehicle can exist not only on a flat road surface but also on an inclined road surface. Further, the internal combustion engine can be mounted on the vehicle in a tilted or straight manner. Therefore, the internal combustion engine mounted on the vehicle tilts in various directions, front, rear, left and right. However, with the cylinder block described in Patent Document 1, when the internal combustion engine is tilted so that the cylinder axis of each cylinder of the internal combustion engine is tilted around the cylinder row direction, the inside of the cylinder head through the oil drain hole is used. Cannot return oil to the crankcase.

  On the other hand, among internal combustion engines, there is an internal combustion engine provided with a ventilation passage that communicates the inside of the cylinder head and the crank chamber in order to improve the ventilation of the crank chamber. In such an internal combustion engine, it is desired that the crank chamber can be properly ventilated through the ventilation passage even when the internal combustion engine is tilted so that the cylinder axis of each cylinder is tilted around the cylinder row direction. .

  Therefore, the present invention has been devised in view of such points, and the purpose thereof is even when the internal combustion engine is tilted such that the cylinder axis of each cylinder of the internal combustion engine is tilted around the cylinder row direction. The purpose is to ensure a smooth flow of fluid between the cylinder head and the crank chamber.

  In order to achieve the above object, an internal combustion engine according to the present invention includes a communication passage that communicates the inside of a cylinder head and a crank chamber, and a space of the crank chamber that is located closer to the cylinder head than the journal of the crankshaft. An internal combustion engine comprising a wall portion divided into corresponding regions, comprising an intermediate passage formed in the wall portion so as to communicate with two different passages communicating with the crank chamber, and at least one of the two different passages Is the communication path.

  According to the above configuration, the internal combustion engine of the present invention includes the intermediate passage formed in the wall portion so as to communicate with two different passages communicating with the crank chamber, and at least one of the two different passages is the communication passage. Since it is a passage, the fluid flow through the communication passage communicating the inside of the cylinder head and the crank chamber is urged through the intermediate passage. Therefore, even when the internal combustion engine is tilted so that the cylinder axis of each cylinder of the internal combustion engine is tilted around the cylinder row direction, a smooth fluid flow is ensured between the cylinder head and the crank chamber. It becomes possible.

  In the internal combustion engine, the two different passages are two communication passages on different sides of a plane defined by two axes of cylinders located adjacent to each other so as to sandwich the wall portion where the intermediate passage is formed. Good to be. In this way, when the internal combustion engine is tilted such that the cylinder axis of each cylinder of the internal combustion engine is tilted around the cylinder row direction, the fluid in one of the two communication paths passes through the intermediate path. Thus, it is possible to flow to the other communication path.

  In the above various internal combustion engines, the intermediate passage is formed in the wall portion where the intermediate passage is formed, and communicates the two regions of the crank chamber that are adjacent to each other with the wall portion interposed therebetween. It is better to communicate with the through passage. By doing so, the communication passage that communicates with the intermediate passage communicates with the crank chamber via the intermediate passage and the through passage.

  A preferred embodiment of the present invention will be described in detail below. An embodiment is described based on a drawing.

  FIG. 1 conceptually shows an internal combustion engine system to which an embodiment according to the present invention is applied. The internal combustion engine 10 is an inline 4-cylinder internal combustion engine.

  As shown in FIG. 1, an engine body 12 of the internal combustion engine 10 includes a cylinder block 18 that defines a cylinder 16 in which a piston 14 reciprocates, a crankcase 20 provided below the cylinder block 18, An oil pan 22 attached to the lower side of the crankcase 20, a cylinder head 26 attached to the upper side of the cylinder block 18 to define the combustion chamber 24 together with the cylinder block 18 and the piston 14, and attached to the upper side of the cylinder head 26. And a cylinder head cover 27. The intake passage 28 of the internal combustion engine 10 is defined by an air cleaner 30, an intake pipe 32, a surge tank 34, an intake manifold 36, and an intake port 38 formed in the cylinder head 26. The outlet that is the downstream end of the intake port 38 is opened and closed by the intake valve 40. An electronically controlled throttle valve 42 is provided between the air cleaner 30 and the surge tank 34 in the intake passage 28. On the other hand, the exhaust passage 44 of the internal combustion engine 10 is defined by an exhaust port 46, an exhaust manifold, a catalyst, and an exhaust pipe connected to each other. However, FIG. 1 shows only a part of the exhaust port 46 formed in the cylinder head 26 among them. An inlet that is an upstream end of the exhaust port 46 is opened and closed by an exhaust valve 48.

  The amount of intake air supplied to the internal combustion engine 10 is adjusted by the throttle valve 42. The intake air whose amount has been adjusted is supplied from the intake valve 40 to the combustion chamber 24 through the intake passage 28. A mixed gas (air mixture) formed by mixing the intake air and the fuel supplied from a fuel injection valve (not shown) is combusted in the combustion chamber 24. The combustion gas is discharged to the exhaust passage 44 through the exhaust valve 48.

  The internal combustion engine 10 is further provided with a blow-by gas reduction (PCV: Positive Clankcase Ventilation) device 50. The PCV device 50 includes a first PCV passage 52 that is defined by a first communication pipe so as to communicate the inside of the intake passage 28 downstream of the throttle valve 42 and the inside of the cylinder head 26, the inside of the intake passage 28, The second PCV passage 54 defined by the second communication pipe so as to communicate the upstream side of the throttle valve 42 and the inside of the cylinder head 26 and the electronically controlled PCV valve 56 for adjusting the communication state of the first PCV passage 52. With.

  Here, the blow-by gas is a mixed gas that leaks into the crank chamber 58 from the gap between the piston ring and the cylinder 16. Since this blow-by gas contains a large amount of hydrocarbons and moisture and is strongly acidic, if it is too much, it will cause deterioration of engine oil and rust inside the engine. Further, since the blow-by gas contains hydrocarbons, it is not good for the environment to release the blow-by gas to the atmosphere as it is. Therefore, the blow-by gas is forcibly returned to the intake passage 28 using the negative pressure of the intake manifold 36 through the first PCV passage 52 during the light load operation. On the other hand, during high load operation, blow-by gas is forcibly returned to the intake passage 28 through the first PCV passage 52 and the second PCV passage 54 using the negative pressure of the intake manifold 36 in the same manner. An example of the flow of blow-by gas and fresh air during light load operation is indicated by arrows in FIG. In FIG. 1, black arrows indicate the flow of blow-by gas, white arrows indicate the flow of fresh air, and hatched arrows indicate the flow of oil.

  A ventilation passage 60 used to recirculate such blow-by gas from the crank chamber 58 into the cylinder head 26 and the like generated when the mixed gas leaks from the gap between the piston ring and the cylinder 16 to the crank chamber 58 is provided in the cylinder block. 18 is formed. 2 is a perspective view of the cylinder block 18, FIG. 3 is a top view of the block main body 62 of the cylinder block 18, FIG. 4 is a bottom view of the block main body 62, and FIG. FIG. 5 is a sectional view taken along the line AA, and FIG. 6 conceptually shows a sectional view taken along the line BB of FIG. 3 of the block body.

  The cylinder block 18 includes a block main body 62 and a cylinder structure 64. The block main body 62 is formed including an outer wall portion 70 for accommodating the cylinder 16 of the cylinder structure 64 and a main body flange portion 72 for mounting the cylinder structure 64. Further, here, the block main body 62 is an upper crankcase that forms a space located above the crank chamber 58 for accommodating the crankshaft 66, that is, a space located closer to the cylinder head 26 than the crank journal (main shaft) of the crankshaft 66. 68 is integrally formed. The crankcase 20 may be referred to as a lower crankcase with respect to the upper crankcase 68 formed integrally with the cylinder block 18. The cylinder structure 64 includes a plurality of cylinders 16 (first cylinder 16A, second cylinder 16B, third cylinder 16C, fourth cylinder 16D) and a cylinder flange portion 74 for placing the cylinder head 26 thereon. It is integrally molded. As shown in FIG. 2, in the cylinder block 18, the block main body 62 and the cylinder structure 64 are combined with the main body flange portion 72 and the cylinder flange portion 74 being in contact with each other.

  A cylinder housing portion 75 for housing the cylinder 16 is formed in an area surrounded by the inner peripheral surface (outer wall inner peripheral surface) 70 </ b> R of the outer wall portion 70 inside the outer wall portion 70. The outer wall inner peripheral surface 70 </ b> R is formed in a shape corresponding to the outer peripheral surface of the cylinder 16.

  In a state where the cylinder structure 64 is assembled to the block main body 62, the outer peripheral surface 70R of the outer wall and the outer peripheral surface of the cylinder 16 face each other with a predetermined interval. In the cylinder housing portion 75, a space formed between the outer peripheral surface 70R of the outer wall portion and the outer peripheral surface of the cylinder 16 is used as a water jacket. The outer wall portion 70 is provided with a cooling water port 70H used for inflow / outflow of the cooling water with respect to the water jacket (see FIG. 2).

  A main body deck surface 72 </ b> T for placing the cylinder flange portion 74 of the cylinder structure 64 is formed on the top of the block main body 62. The main body flange portion 72 is provided with an opening 72H of a fastening hole for inserting a bolt.

  In the upper crankcase 68, a plurality of partition walls 76 are provided at substantially equal intervals in the cylinder row direction between the side wall 74A and the side wall 74B at both ends in the cylinder row direction. Here, since the internal combustion engine 10 is an in-line four-cylinder internal combustion engine, there are provided three partition walls including a first partition wall 76A, a second partition wall 76B, and a third partition wall 76C (see FIG. 3).

  Bearing portions 78 for rotatably supporting a crank journal (hereinafter referred to as a journal) of the crankshaft 66 are formed on the side walls 74A, 74B and the partition walls 76A, 76B, 76C. The crankshaft 66 is assembled to the block body 18 by the journal being supported through a crank cap (not shown) from a direction facing the inner peripheral surface of the bearing portion 78.

  The upper crank chamber 59U, which is the upper space (space) of the crank chamber 58 located on the cylinder head 26 side with respect to the journal of the crankshaft 66, is a partition wall 76A located above the journal of the crankshaft 66, that is, on the cylinder head 26 side. , 76B and 76C are divided into four regions corresponding to each cylinder 16 in the cylinder row direction. Here, of the four regions, a region formed at a position corresponding to the first cylinder 16A is a first crank chamber 59A, and a region formed at a position corresponding to the second cylinder 16B is a second crank chamber 59B. An area formed at a position corresponding to the third cylinder 16C is referred to as a third crank compartment 59C, and an area formed at a position corresponding to the fourth cylinder 16D is referred to as a fourth crank compartment 59D. In short, the first crank compartment 59A is defined between the side wall 74A of the upper crankcase 68 and the first partition wall 76A. The second crank compartment 59B is defined between the first partition wall 76A and the second partition wall 76B. The third crank compartment 59C is defined between the second partition wall 76B and the third partition wall 76C. Furthermore, the fourth crank compartment 59D is defined between the third partition wall 76C and the side wall 74B.

  A plurality of the ventilation passages 60 are formed in the vertical direction so as to penetrate the cylinder block 18. Here, three ventilation passages 60 extending substantially in the cylinder axis direction are provided in the block main body 62, and each of them penetrates the first partition wall 76A, the second partition wall 76B, or the third partition wall 76C. Each of these three ventilation passages 60 communicates between the crank chamber 58 and the cylinder head 26. More precisely, each of the ventilation passages 60 communicates with the space formed above the cylinder block 18 by the crank chamber 58 and the cylinder head 26 and the cylinder head cover 27. In order to prevent oil from flowing into the ventilation passage 60, the ventilation passage 60 has an upper end formed so as to extend into the space inside the cylinder head 26. These ventilation passages 60 are arranged in parallel to one side of a plane in which all of the cylinder axis ca that is the central axis of each of the four cylinders 16 are substantially included. In the present embodiment, the ventilation passages 60 are arranged in the vicinity of one side surface of the cylinder block 18 so as to be arranged in the cylinder row direction. In the present embodiment, the ventilation passage 60 has a rectangular cross-sectional shape, but may have various shapes such as a circle and a polygon. Such a ventilation passage 60 allows blow-by gas in the crank chamber 58 to flow into the cylinder head 26. It is also possible for fresh air, that is, air, to reach the crank chamber 58 from the cylinder head 26 through these ventilation passages 60. Therefore, the crank chamber 58 can be ventilated. As a result, the pressure of the crank chamber 58 can be adjusted.

  Further, an oil dropping passage (oil dropping hole) 80 is formed so as to penetrate the cylinder block 18 in the vertical direction so as to communicate the inside of the cylinder head 26 and the crank chamber 58. In the present embodiment, each oil drop passage 80 is formed in the cylinder block 18 at a position facing each ventilation passage 60. That is, each of the oil drop passages 80 is formed in a pair with one ventilation passage 60 so as to penetrate the first partition wall 76A, the second partition wall 76B, or the third partition wall 76C. These oil drop passages 80 are different from one side on which the ventilation passage 60 is disposed, which is a plane that substantially includes the cylinder axis ca, that is, a plane that substantially bisects the cylinder block 18 in a direction orthogonal to the cylinder row direction. It arrange | positions so that it may rank in a cylinder row direction on the other side. In other words, these oil drop passages 80 are arranged in the cylinder row direction in the vicinity of one side surface different from the side where the ventilation passage 60 of the cylinder block 18 is arranged. In the present embodiment, the oil drop passage 80 has a rectangular cross-sectional shape, but may have various shapes such as a circle and a polygon. These oil drop passages 80 allow oil such as engine lubricating oil that has reached the inside of the cylinder head 26 to reach the crank chamber 58 and be collected in the oil pan 22. Note that blow-by gas, air, and the like can also flow through the oil dropping passage 80.

  Each of the partition walls 76A, 76B, and 76C is formed with a hole (through passage) 82 that penetrates them in the cylinder row direction. Here, these holes are referred to as a first respiratory passage 82A, a second respiratory passage 82B, and a third respiratory passage 82C, respectively. That is, the first crank compartment 59A and the second crank compartment 59B are communicated by the first breathing passage 82A formed in the first partition wall 76A. The second crank compartment 59B and the third crank compartment 59C are communicated by a second breathing passage 82B formed in the second partition wall 76B. The third crank compartment 59C and the fourth crank compartment 59D are communicated by a third breathing passage 82C formed in the third partition wall 76C. Accordingly, the four first to fourth crank chambers 59A, 59B, 59C, 59D communicate with each other, and fluid movement between them is allowed. The movement of fluid, particularly blow-by gas or air, through the breathing passage 82 can reduce the pressure fluctuation in the crank chamber 58 and the pumping loss due to the reciprocating motion of the piston 14.

  Further, in the cylinder block 18, a passage 88 is formed in the partition wall 76 of the cylinder block 18 located above the journal of the crankshaft 66. The passage 88 is formed so as not to penetrate the cylinder block 18. The passage 88 extends in a direction intersecting with a plane defined by the two cylinder axes ca of the two cylinders 16 adjacent to each other so as to sandwich the partition wall 76 in which the passage 88 is formed. That is, in this embodiment, the passage 88 includes the cylinder axis ca and extends in a direction intersecting with a plane including an α axis parallel to the cylinder axis ca and a β axis extending in the cylinder row direction. In particular, in the present embodiment, the passage 88 is formed so as to extend in the γ-axis direction orthogonal to the α-axis and the β-axis. The passage 88 communicates with a set of ventilation passages 60 and an oil dropping passage 80 related to one arbitrary partition wall 76, and also communicates with a breathing passage 82 related to the partition wall 76. As a result, the passage 88 acts between them to facilitate the flow of air, blowby gas or oil through the ventilation passage 60, the oil drop passage 80, and the breathing passage 82. Therefore, this passage 88 is hereinafter referred to as an “intermediate passage”.

  The relationship between these four types of passages in this embodiment is summarized as follows. An intermediate passage 88 formed in any partition wall 76 communicates with two different passages 60, 80 communicating with the crank chamber 58. Each of the two different passages 60 and 80 is a communication passage that connects the inside of the cylinder head 26 and the crank chamber 58, and the passages 60 and 80 sandwich the partition wall 76 in which the intermediate passage 88 is formed. They are on different sides of the plane defined by the two cylinder axes ca of the cylinders 16 at adjacent positions. Further, such an intermediate passage 88 is formed in the partition wall 76 in which the intermediate passage 88 is formed, and a breathing passage that communicates the two regions of the crank chamber 58 that are adjacent to each other with the partition wall 76 interposed therebetween. 82.

  The flow of the fluid in the internal combustion engine 10 having the above-described configuration will be described based on the schematic diagram of FIG. FIG. 7A is a diagram schematically illustrating an example of a fluid flow when the internal combustion engine 10 is horizontally disposed. FIG. 7B shows the flow of fluid when the cylinder axis ca of each cylinder 16 of the internal combustion engine 10 is tilted around the cylinder row direction and when the oil dropping passage 80 is tilted downward. It is the figure which represented an example typically. FIG. 7C shows an example of the fluid flow when the cylinder axis ca of each cylinder 16 of the internal combustion engine 10 is tilted around the cylinder row direction and the ventilation passage 60 is tilted downward. FIG. As in FIG. 1, the black arrow in FIG. 7 represents the flow of blow-by gas, the white arrow represents the flow of fresh air, and the hatched arrow represents the flow of oil.

  According to FIG. 7A, oil flows or falls from the inside of the cylinder head 26 to the crank chamber 58 via the oil dropping passage 80 (see arrow h). In addition, blow-by gas flows from the crank chamber 58 into the cylinder head 26 through the ventilation passage 60 (see arrow i), whereas air flows from the cylinder head 26 into the crank chamber 58 through the ventilation passage 60. Flowing (see arrow j). On the other hand, the blow-by gas that reaches from any of the first to fourth crank compartments 59A to D via the breathing passage 82 reaches the intermediate passage 88 (see arrow ii), and flows from the intermediate passage 88 to the ventilation passage 60. And flows into the cylinder head 26. In this manner, a flow of fluid such as blow-by gas, air, and oil is ensured between the cylinder head 26 and the crank chamber 58.

  7B, even if the end of the oil drop passage 80 on the side of the oil pan 22 is blocked by oil due to the inclination of the internal combustion engine 10, the oil drop passage 80 The flow of blowby gas, air, etc. through the ventilation passage 60 is ensured through the intermediate passage 88. Further, similarly, as shown in FIG. 7C, even if the internal combustion engine 10 tilts and the end portion of the ventilation passage 60 on the oil pan 22 side is blocked by the oil, the oil is dropped. The flow of blowby gas, air, and the like through the passage 80 and the ventilation passage 60 is ensured through the intermediate passage 88. Therefore, even when the internal combustion engine 10 is tilted so that the cylinder axis ca of the cylinder 16 of the internal combustion engine 10 is tilted (turned) around the cylinder row direction, the above-described operation between the inside of the cylinder head 26 and the crank chamber 58 is performed. A smooth flow of fluid is ensured.

  Further, as shown in FIG. 8, the piston 14 reciprocates in the cylinder axis direction in a section D between the dotted line L1 and the dotted line L2. At this time, the oil (see arrow hh) on the inner wall surface of the cylinder 16 is scraped off to the crank chamber 58 side by the piston ring of the piston 14. A part of the oil thus scraped off can flow into the breathing passage 82 of the partition wall 76 on the lower side of the section D. Such oil reaches from the intermediate passage 88 communicating with the breathing passage 82 to the oil dropping passage 80 and / or the ventilation passage 60, preferably the oil dropping passage 80, and reaches the space in the crank chamber 58 and the oil pan 22. (See arrow h). Therefore, since it is possible to prevent all of the oil thus scraped off from being directly applied to the crankshaft 66, an increase in the ratio of bubbles contained in the oil is suppressed. Further, since oil can be reduced from splashing into the crank chamber 58 on the crankshaft 66, an increase in pressure in the crank chamber 58 is suppressed. Therefore, an increase in rotational resistance of the crankshaft 66, that is, an increase in friction is suppressed.

  In this way, even when the internal combustion engine 10 is tilted so that the cylinder axis ca of the internal combustion engine 10 is tilted around the cylinder row direction, oil and blow-by between the cylinder head 26 and the crank chamber 58 can be achieved. Since an appropriate flow of gas and air is ensured, the ventilation in the internal combustion engine 10 is improved. Therefore, generation of sludge in the oil can be reduced, and oil deterioration can be suppressed.

  Since the intermediate passage 88 is provided in the wall portion that is the partition wall 76 of the internal combustion engine 10, the provision of the intermediate passage 88 does not increase the size of the internal combustion engine 10. Therefore, by providing the intermediate passage 88, the internal combustion engine 10 does not become heavy.

  In the above embodiment, the intermediate passage 88 extends in a direction perpendicular to the cylinder axis ca and the cylinder row direction. However, the intermediate passage 88 is inclined, that is, slanted so that the end of the intermediate passage 88 on the oil drain passage 80 side is located lower than the end of the ventilation passage 60 side, that is, on the oil pan 22 side. Preferably it is formed. In this way, for example, oil that reaches the intermediate passage 88 via the breathing passage 82 can flow to the oil dropping passage 80.

  In the above-described embodiment, the intermediate passage 88 is provided so as to communicate with the ventilation passage 60, the oil dropping passage 80, and the breathing passage 82, but may not be provided so as to communicate with these three passages. For example, the intermediate passage 88 may be formed so as to communicate with only one ventilation passage 60 and one oil dropping passage 80. Alternatively, the intermediate passage 88 may be formed so as to communicate with the ventilation passage 60 or the oil dropping passage 80 and the breathing passage 82. That is, the intermediate passage 88 communicates with two or more passages made of one kind selected from the ventilation passage 60, the oil dropping passage 80, and the breathing passage 82, or is selected from them. Further, the partition wall 76 on the journal of the crankshaft 66 of the internal combustion engine 10 may be formed in a direction different from the cylinder row direction so as to communicate two or more kinds of passages.

  Moreover, in the said embodiment, although the one intermediate channel 88 was provided in one partition, ie, a wall part, you may provide two or more. That is, it is preferable that at least one intermediate passage is formed in such one wall portion.

  Moreover, although the internal combustion engine of the said embodiment was a wet sump type internal combustion engine, the internal combustion engine to which this invention is applied may be a dry sump type internal combustion engine. In the wet sump type internal combustion engine, the oil accumulated in the oil pan is directly supplied to the sliding portion by an oil pump (not shown), whereas in the dry sump type internal combustion engine, the oil is collected from the oil pan to the reservoir tank by the recovery pump. Is temporarily recovered, and oil is supplied from the reservoir tank to the sliding portion or the like by a supply pump. Therefore, when the present invention is applied to a dry sump type internal combustion engine, the increase in bubbles in the oil is reduced as described above, so that the oil is recovered and supplied appropriately using both oil pumps.

  The intermediate passage 88 formed in the partition wall 76 located on the cylinder head side with respect to the journal of the crankshaft 66 of the above embodiment can be formed by a core when the block main body 62 is formed. Alternatively, the intermediate passage 88 can be formed by machining.

Although the present invention has been described with a certain degree of concreteness, various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention described in the claims. Must be understood. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

1 is a conceptual diagram of an internal combustion engine system to which an embodiment of the present invention is applied. It is a perspective view of the cylinder block of the internal combustion engine of an embodiment. It is a top view of the block main body of the cylinder block of FIG. It is a bottom view of the block main body of the cylinder block of FIG. FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. FIG. 4 is a schematic cross-sectional view taken along line BB in FIG. 3. It is a schematic diagram for demonstrating an example of the flow of the fluid in embodiment. It is a mimetic diagram for explaining an example of a flow of oil in an embodiment.

Explanation of symbols

10 Internal combustion engine 58 Crank chamber 60 Ventilation passage 80 Oil drop passage 88 Intermediate passage

Claims (3)

In the internal combustion engine comprising a communication path that communicates the inside of the cylinder head and the crank chamber, and a wall portion that divides the space of the crank chamber located on the cylinder head side with respect to the journal of the crankshaft into regions corresponding to the cylinders,
An intermediate passage formed in the wall so as to communicate with two different passages communicating with the crank chamber;
An internal combustion engine, wherein at least one of the two different passages is the communication passage.   The two different passages are the two communication passages on different sides of a plane defined by two axes of cylinders adjacent to each other so as to sandwich the wall portion where the intermediate passage is formed. The internal combustion engine according to claim 1.   The intermediate passage is formed in the wall portion in which the intermediate passage is formed, and communicates with a through passage that communicates the two regions of the crank chamber that are adjacent to each other with the wall portion interposed therebetween. The internal combustion engine according to claim 1, wherein

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