engine

Abstract

To enable both of enhancement of output of an engine and enhancement of cooling efficiency of a portion on a top dead center side of a cylinder liner.SOLUTION: An engine 100 includes a cylinder block 1 having a through hole 11 and a cylinder liner 4 provided in the through hole 11. The cylinder liner 4 includes: a flange part 44 having an outer diameter larger than the through hole 11; and a first fitting part 41 and a second fitting part 42 fitted to the through hole 11. The engine also includes: a first recessed part 51C forming a first refrigerant jacket 51 in a circumferential direction between the flange part 11 and the first fitting part 41; and a second recessed part 52C forming a second refrigerant jacket 52 between the first fitting part 41 and the second fitting part 42.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an engine equipped with a cylinder liner. [Background technology]

[0002] When an engine equipped with a cylinder liner is made to have a high output, the amount of heat released to the part of the cylinder liner on the top dead center side increases. Therefore, conventionally, techniques for improving the cooling performance of the part of the cylinder liner on the top dead center side have been considered. For example, Patent Document 1 describes a cylinder liner that is a wet type cylinder liner in which a cooling liquid passage is formed around a body part fitted into a cylinder block, and in which a flange part is provided around the outer circumferential surface of a fitting part that fits into the mouth part of the cylinder block, a cooling groove is provided around the outer circumferential surface of the fitting part closer to the cooling liquid passage than the flange part, and a communication passage that communicates the cooling groove and the cooling liquid passage is formed in the fitting part, and a part of the cooling liquid flowing through the cooling liquid passage flows into the cooling groove through the communication passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-79576 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, since a part of the fitting portion exists between the cooling groove and the flange portion, it is difficult to improve the cooling performance of the flange portion. The cooling performance can also be improved by increasing the discharge pressure of the refrigerant pump to increase the flow rate of the refrigerant, but in that case, the consumption of shaft output by the refrigerant pump increases, hindering the increase in engine power.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, an object of the present invention is to achieve both higher engine output and more efficient cooling of the portion of the cylinder liner on the top dead center side. [Means for solving the problem]

[0006] In order to solve the above problems, the engine of the present invention comprises a cylinder block having a through hole and a cylinder liner provided in the through hole, the cylinder liner comprising a flange portion having an outer diameter larger than the through hole, and first and second fitting portions that fit into the through hole, a first recess that forms a first refrigerant jacket along the circumferential direction between the flange portion and the first fitting portion, and a second recess that forms a second refrigerant jacket between the first fitting portion and the second fitting portion.

[0007] An end of the first recess on the flange portion side may be connected to an end face of the flange portion on the first recess side.

[0008] The cylinder block may include a communication recess provided on an inner surface of the through hole, the communication recess forming a communication passage that connects the first refrigerant jacket and the second refrigerant jacket.

[0009] The first fitting portion may have an annular shape without discontinuities over the entire area in the circumferential direction.

[0010] The communication recess may have a flat shape with a width in the circumferential direction greater than a width in the radial direction.

[0011] The cylinder block may include a communication recess provided on an inner surface of the through hole, the communication recess forming a communication passage connecting the first refrigerant jacket and the second refrigerant jacket, and a main refrigerant passage through which the refrigerant is supplied from a refrigerant supply source directly to the first refrigerant jacket without passing through the second refrigerant jacket and the communication passage.

[0012] The engine may include a cylinder head, and the cylinder block may include a head communication passage that supplies refrigerant from the first refrigerant jacket to the cylinder head.

[0013] The cylinder block may include a communication recess provided on an inner surface of the through hole and forming a communication passage connecting the first refrigerant jacket and the second refrigerant jacket, the cylinder head may include one or more intake ports and one or more exhaust ports, the first refrigerant jacket may include an intake side path extending from the main refrigerant passage to the head communication passage via a side where the intake ports are unevenly located, and an exhaust side path extending from the main refrigerant passage to the head communication passage via a side where the exhaust ports are unevenly located, and the communication recess may be provided in each of the intake side path and the exhaust side path, and a distance from the communication passage provided in the exhaust side path to the head communication passage may be longer than a distance from the communication passage provided in the intake side path to the head communication passage. Effect of the Invention

[0014] According to the present invention, it is possible to achieve both high engine output and high efficiency cooling of the portion of the cylinder liner on the top dead center side. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of an engine according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of an engine according to an embodiment of the present invention. [Diagram 3] 1 is a side view showing a coolant flowing inside an engine according to an embodiment of the present invention; [Figure 4] 1 is a perspective view showing a refrigerant flowing inside an engine according to an embodiment of the present invention; [Diagram 5] 1 is a perspective view showing a refrigerant flowing inside an engine according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an engine 100 according to an embodiment of the present invention will be described with reference to the drawings.

[0017] First, the overall configuration of the engine 100 will be described. Figures 1 and 2 are cross-sectional views of the engine 100. Of these, Figure 1 shows a cross-section taken along line II in Figure 2, and Figure 2 shows a cross-section taken along line II-II in Figure 1. In Figure 2, the piston 6 is omitted from illustration. In this embodiment, for convenience, an example is shown in which the cylinder head 8 is located above the cylinder block 1, but the engine 100 may be used in any position.

[0018] The engine 100 includes a cylinder block 1, a cylinder liner 4, a piston 6, a connecting rod 7, and a cylinder head 8.

[0019] The cylinder block 1 has a through hole 11 that penetrates in the vertical direction. The cross section of the through hole 11 when viewed from the vertical direction is circular. A top deck 13, which is the upper end portion of the cylinder block 1, is formed flat. A crankcase (not shown) that houses a crankshaft is provided at the lower portion of the cylinder block 1. A plurality of bolt holes 16 with female threads are provided circumferentially around the through hole 11.

[0020] The cylinder liner 4 includes a cylindrical portion 43 formed in a cylindrical shape, and a flange portion 44 formed on the upper end of the cylindrical portion 43 and having an outer diameter larger than that of the cylindrical portion 43. The cylindrical portion 43 is inserted into the through hole 11, and the lower surface of the flange portion 44 contacts the top deck 13.

[0021] The piston 6 is housed inside the cylinder liner 4. A concave combustion chamber 61 is provided at the upper end of the piston 6. A plurality of ring grooves 64 are provided along the circumferential direction on the outer circumferential surface of the piston 6, and a piston ring 63 is provided in each ring groove 64. A scraper ring 45 is provided at the inner upper end of the cylindrical portion 43 of the cylinder liner 4. The scraper ring 45 is provided above the uppermost piston ring 63 when the piston 6 is located at the top dead center.

[0022] The small end of the connecting rod 7 is connected to the piston 6 via a piston pin 62. The big end of the connecting rod 7 is connected to the crankshaft via a crank pin (not shown).

[0023] A head recess 85, which is a circular recess, is provided on the underside of the cylinder head 8. The inner diameter of the head recess 85 is equal to the outer diameter of the flange portion 44 of the cylinder liner 4. The depth of the head recess 85 is equal to the thickness of the flange portion 44 in the vertical direction. The flange portion 44 is accommodated in the head recess 85. The cylinder head 8 has bolt holes corresponding to the bolt holes 16 of the cylinder block 1, and is fixed to the cylinder block 1 using bolts (not shown). A gasket 14 is provided between the top deck 13 and the underside of the cylinder head 8, outside the flange portion 44.

[0024] The cylinder head 8 is provided with an injector 83 that injects fuel. The injector 83 is provided at a position corresponding to the center of the piston 6. The injection port of the injector 83 is exposed from the bottom surface of the cylinder head 8. One or more air intake ports 81 and one or more exhaust ports 82 are provided around the injector 83. In this example, two air intake ports 81 and two exhaust ports 82 are provided. The two air intake ports 81 are adjacent to each other in the circumferential direction. The two exhaust ports 82 are also adjacent to each other in the circumferential direction. The air intake port 81 and the exhaust port 82 are provided with an air intake valve 81V and an exhaust valve 82V, respectively.

[0025] Next, a configuration for cooling engine 100 will be described (see Figs. 1 to 5). Fig. 3 is a side view showing the refrigerant flowing inside engine 100. Figs. 4 and 5 are perspective views showing the refrigerant flowing inside engine 100. In other words, Figs. 3 to 5 are virtual views of the surface of a passage through which the refrigerant flows, viewed from outside the passage.

[0026] The engine 100 comprises a cylinder block 1 having a through hole 11 and a cylinder liner 4 provided in the through hole 11. The cylinder liner 4 comprises a flange portion 44 having an outer diameter larger than that of the through hole 11, and a first fitting portion 41 and a second fitting portion 42 that fit into the through hole 11. The cylinder liner 4 also comprises a first recess 51C that forms a first refrigerant jacket 51 along the circumferential direction between the flange portion 11 and the first fitting portion 41, and a second recess 52C that forms a second refrigerant jacket 52 between the first fitting portion 41 and the second fitting portion 42.

[0027] The outline of the cylinder block 1 and the cylinder liner 4 has already been described, so the following mainly describes in detail the configuration of the cylindrical portion 43 of the cylinder liner 4.

[0028] [First fitting part, second fitting part] The first fitting portion 41 and the second fitting portion 42 (see FIG. 1) have circular inner and outer peripheries in a cross section viewed from the top and bottom. In other words, the first fitting portion 41 and the second fitting portion 42 form an annular shape without discontinuities over the entire circumferential area. The first fitting portion 41 is provided on the side of the piston ring 63 when the piston 6 is located at the top dead center. The second fitting portion 42 is provided on the side near the bottom end of the piston 6 when the piston 6 is located at the top dead center. The first fitting portion 41 and the second fitting portion 42 are press-fitted into the through hole 11.

[0029] [First recess, first refrigerant jacket, first main refrigerant passage] The first recess 51C (see FIG. 1) is provided between the flange portion 44 and the first fitting portion 41. The first recess 51C is formed in an annular shape along the circumferential direction. The first refrigerant jacket 51 (see FIGS. 1 to 5) is an annular passage surrounded by the first recess 51C and the inner surface of the through hole 11.

[0030] The distribution chamber 12 is provided on the side of the cylinder block 1 (see FIGS. 3 to 5). The refrigerant is distributed from the distribution chamber 12 to each part of the engine 100 by a pump (not shown). The cylinder block 1 is provided with a first main refrigerant passage 21 (an example of a main refrigerant passage) that supplies the refrigerant from the distribution chamber 12 to a first refrigerant jacket 51. The first main refrigerant passage 21 supplies the refrigerant directly from the distribution chamber 12 to the first refrigerant jacket 51 without passing through a second refrigerant jacket 52 and a communication passage 23, which will be described later.

[0031] The first main refrigerant passage 21 penetrates from the distribution chamber 12 to a position on the inner surface of the through hole 11 corresponding to the first refrigerant jacket 51. An opening of the first main refrigerant passage 21 on the through hole 11 side is a main refrigerant inlet 21A which is an inlet of the refrigerant to the first refrigerant jacket 51. The main refrigerant inlet 21A is provided in a portion of the first refrigerant jacket 51 on the air supply port 81 side (see FIG. 2). In the example of the same figure, the main refrigerant inlet 21A is provided near the right air supply port 81 of the two air supply ports 81, but it is sufficient that the main refrigerant inlet 21A is provided at a position closer to the air supply port 81 than the exhaust port 82.

[0032] An upper end portion of the first recess 51C (an example of an end portion of the first recess 51C on the flange portion 44 side) is connected to a lower end surface of the flange portion 44 (an example of an end surface of the flange portion 44 on the first recess 51C side) (see FIG. 1). That is, there is no portion between the first recess 51C and the flange portion 44 that fits (contacts) with the through hole 11. In other words, the first refrigerant jacket 51 is continuous with the flange portion 44.

[0033] Moreover, the upper end of the first recess 51C is defined by the lower end surface of the flange portion 44. Therefore, the upper end of the first refrigerant jacket 51 has a width in the radial direction. With this configuration, the refrigerant also comes into contact with the lower end surface of the flange portion 44, improving the cooling performance of the flange portion 44.

[0034] Comparing the radial width of the first refrigerant jacket 51 between the upper and lower parts, the width of the lower part is wider than the width of the upper part. Specifically, the first recess 51C has the lower end surface of the flange part 44, a tapered part whose diameter decreases from the top to the bottom, and a curved surface whose diameter increases while curving from the lower end of the tapered part toward the outer circumferential surface of the first fitting part 41. This configuration reduces stress concentration on the first recess 51C.

[0035] [Second recess, second refrigerant jacket, second main refrigerant passage] The second recess 52C (see FIG. 1) is provided between the first fitting portion 41 and the second fitting portion 42. The second recess 52C is formed in an annular shape along the circumferential direction. The second refrigerant jacket 52 (see FIGS. 1 to 5) is an annular passage surrounded by the second recess 52C and the inner surface of the through hole 11. The vertical width of the second recess 52C is wider than the vertical width of the first recess 51C.

[0036] The through hole 11 is provided with a through hole recess 15, which is an annular recess formed along the circumferential direction, in a range corresponding to a portion below the center in the up-down direction of the second recess 52C. With this configuration, the lower part of the second refrigerant jacket 52 has a wider radial width than the upper part.

[0037] The cylinder block 1 is provided with a second main refrigerant passage 22 that supplies refrigerant from the distribution chamber 12 to the second refrigerant jacket 52. The second main refrigerant passage 22 penetrates from the distribution chamber 12 to a position on the inner surface of the through hole 11 corresponding to the second refrigerant jacket 52.

[0038] [First head passage] The cylinder block 1 is provided with a first head communication passage 31 (an example of a head communication passage) that supplies refrigerant from the first refrigerant jacket 51 to a head refrigerant jacket 84 provided in the cylinder head 8 (see Figs. 2 to 5). The first head communication passage 31 penetrates from a position on the inner surface of the through hole 11 corresponding to the first refrigerant jacket 51 to the head refrigerant jacket 84. An opening of the first head communication passage 31 on the through hole 11 side serves as a main refrigerant outlet 31B, which is an outlet for the refrigerant from the first refrigerant jacket 51. The main refrigerant outlet 31B is provided in a portion of the first refrigerant jacket 51 on the exhaust port 82 side (see Fig. 2).

[0039] Moreover, the main refrigerant outlet 31B is provided at a position facing the main refrigerant inlet 21A across the center of the through hole 11. With this configuration, the distance from the main refrigerant inlet 21A to the main refrigerant outlet 31B in the first refrigerant jacket 51 is equal between the upper path and the lower path in Fig. 2. In the example of Fig. 2, of the two upper and lower paths leading from the main refrigerant inlet 21A to the main refrigerant outlet 31B, the air supply port 81 is unevenly located along the upper path, and the air exhaust port 82 is unevenly located along the lower path. Therefore, the upper path is called the air supply side path 511, and the lower path is called the air exhaust side path 512.

[0040] [Second head connection passage] The cylinder block 1 is provided with second head communication passages 32 that supply refrigerant from the second refrigerant jacket 52 to the head refrigerant jacket 84 (see FIGS. 3 to 5). The second head communication passages 32 penetrate from a position on the inner surface of the through hole 11 corresponding to the second refrigerant jacket 52 to the head refrigerant jacket 84. In this example, four second head communication passages 32 are provided on all four sides of the through hole 11.

[0041] [Communication recess, communication passage] The cylinder block 1 is provided with a communication recess 23C that is provided on the inner surface of the through hole 11 and forms a communication passage 23 that communicates between the first refrigerant jacket 51 and the second refrigerant jacket 52 (see Figs. 2 to 5). The communication recess 23C is groove-shaped along the vertical direction. The upper end of the communication recess 23C is located above the lower end of the first refrigerant jacket 51. The lower end of the communication recess 23C is located below the upper end of the second refrigerant jacket 52. With this configuration, the communication passage 23 that communicates between the first refrigerant jacket 51 and the second refrigerant jacket 52 is formed on the cylinder block 1 side.

[0042] The communication recess 23C has a flat shape with a circumferential width greater than its radial width. The wider the circumferential width, the larger the area with which the refrigerant comes into contact with the first fitting portion 41, thereby improving the cooling performance.

[0043] The communication passage 23 is provided at least at one location in the circumferential direction. In this example, one communication passage 23 is connected to each of the air supply side passage 511 and the air exhaust side passage 512 of the first refrigerant jacket 51 in Fig. 2. Comparing the distance from the communication passage 23 to the main refrigerant outlet 31B in the air supply side passage 511 and the air exhaust side passage 512, the distance from the communication passage 23 to the main refrigerant outlet 31B in the air exhaust side passage 512 is longer than the distance from the communication passage 23 to the main refrigerant outlet 31B in the air supply side passage 511.

[0044] Here, the positional relationship between the main refrigerant inlet 21A, the main refrigerant outlet 31B, and the supply and exhaust side communication passages 23 will be described. Since the temperature of the exhaust gas is higher than that of the supply gas, more heat is released to the exhaust port 82 side than to the supply port 81 side for the cylinder liner 4. Therefore, in order to efficiently cool the cylinder liner 4, it is desirable to provide the main refrigerant inlet 21A at a position close to the supply port 81 and the main refrigerant outlet 31B at a position close to the exhaust port 82.

[0045] For example, in FIG. 2, if the main refrigerant inlet 21A is provided at a position equidistant from two air supply ports 81, and the main refrigerant outlet 31B is provided at a position equidistant from two exhaust ports 82, comparing the counterclockwise route with the clockwise route, the heat distribution from the main refrigerant inlet 21A to the main refrigerant outlet 31B is the same, so there is no need to make the distance from the communicating passage 23 to the main refrigerant outlet 31B different for the two routes.

[0046] However, in reality, due to design constraints (for example, to restrict the width of the engine 100 in the direction perpendicular to the crankshaft), the main refrigerant inlet 21A may be provided at a position that is not equidistant from the two intake ports 81, as shown in FIG. 2. As a result, the intake port 81 is unevenly located in one of the two paths (the intake side path 511 described above), and the exhaust port 82 is unevenly located in the other path (the exhaust side path 512 described above). In this case, since more heat is released in the exhaust side path 512 than in the intake side path 511, it is necessary to improve the cooling performance of the exhaust side path 512 more than that of the intake side path 511. Moreover, if the intake side path 511 is cooled too much, the gas supplied may not reach an appropriate temperature, resulting in incomplete combustion. Therefore, in this embodiment, the distance from the connecting passage 23 to the main refrigerant outlet 31B in the exhaust side path 512 is made longer than the distance from the connecting passage 23 to the main refrigerant outlet 31B in the supply side path 511, thereby improving the cooling performance of the exhaust side path 512 and suppressing overcooling of the supply side path 511.

[0047] Next, the operation of the above configuration will be described. The refrigerant that has passed through the first main refrigerant passage 21 from the distribution chamber 12 and reached the main refrigerant inlet 21A is divided and flows into the intake side passage 511 (arrow F1 in FIG. 2) and the exhaust side passage 512 (arrow F2). On the other hand, the refrigerant that has been supplied from the distribution chamber 12 to the second refrigerant jacket 52 through the second main refrigerant passage 22 cools the second recess 52C of the cylinder liner 4 and flows into the four second head communication passages 32, the intake side communication passage 23, and the exhaust side communication passage 23.

[0048] The refrigerant that flows into the second head communication passage 32 flows into the head refrigerant jacket 84 to cool the cylinder head 8, and then returns to the distribution chamber 12 through a predetermined path (not shown). The refrigerant that flows into the air intake side communication passage 23 flows along the air intake side path 511 (arrow F3) together with the refrigerant that flows into the main refrigerant inlet 21A (arrow F1), and the refrigerant that flows into the exhaust side communication passage 23 flows along the exhaust side path 512 (arrow F4) together with the refrigerant that flows into the main refrigerant inlet 21A (arrow F2). The refrigerant that flows through the air intake side path 511 and the exhaust side path 512 cools the first recess 51C of the cylinder liner 4, flows from the main refrigerant outlet 31B through the first head communication passage 31 into the head refrigerant jacket 84 to cool the cylinder head 8, and returns to the distribution chamber 12.

[0049] The engine 100 according to the present embodiment described above includes the cylinder block 1 having the through hole 11 and the cylinder liner 4 provided in the through hole 11. The cylinder liner 4 includes a flange portion 44 having an outer diameter larger than that of the through hole 11, a first fitting portion 41 and a second fitting portion 42 that fit into the through hole 11, a first recess 51C that forms a first refrigerant jacket 51 along the circumferential direction between the flange portion 11 and the first fitting portion 41, and a second recess 52C that forms a second refrigerant jacket 52 between the first fitting portion 41 and the second fitting portion 42. With this configuration, the portion from the flange portion 44 to the first fitting portion 41 is cooled without consuming axial power, so that it is possible to achieve both high power output of the engine 100 and high efficiency cooling of the portion of the cylinder liner 4 on the top dead center side.

[0050] Furthermore, in the engine 100 according to this embodiment, the end of the first recess 51C on the flange portion 44 side is connected to the end face of the flange portion 44 on the first recess 51C side. With this configuration, the first refrigerant jacket 51 is expanded toward the flange portion 44 side, so that the part of the cylinder liner 4 on the top dead center side can be cooled more efficiently.

[0051] In addition, according to the engine 100 of this embodiment, the cylinder block 1 is provided with a communication recess 23C that is provided on the inner surface of the through hole 11 and forms a communication passage 23 that communicates the first refrigerant jacket 51 and the second refrigerant jacket 52. With this configuration, the refrigerant flows between the second refrigerant jacket 52 and the first refrigerant jacket 51, so that the cooling performance can be improved. When the communication recess 23C is provided in the cylinder liner 4, in order to prevent the position of the communication recess 23C from differing for each cylinder liner 4, it is necessary to align the circumferential direction of the cylinder liner 4 to a predetermined direction when assembling the cylinder liner 4. In contrast, in this embodiment, since the communication recess 23C is provided in the cylinder block 1, there is no restriction on the circumferential direction of the cylinder liner 4. Therefore, the assembling work of the cylinder liner 4 is reduced.

[0052] Furthermore, according to the engine 100 of this embodiment, the first fitting portion 41 has a circular ring shape with no discontinuous parts over the entire circumferential area, so that the thermal deformation of the cylinder liner 4 can be made uniform in the circumferential direction.

[0053] Furthermore, in the engine 100 according to this embodiment, the communication recess 23C has a flat shape with a circumferential width greater than its radial width, so that the area of ​​the first fitting portion 41 that comes into contact with the refrigerant can be increased.

[0054] Furthermore, according to the engine 100 of this embodiment, the cylinder block 1 is provided with the communication recess 23C that is provided on the inner surface of the through hole 11 and that forms the communication passage 23 that connects the first refrigerant jacket 51 and the second refrigerant jacket 52, and the first main refrigerant passage 21 that supplies refrigerant from a refrigerant supply source directly to the first refrigerant jacket 51 without passing through the second refrigerant jacket 52 and the communication passage 23, so that the flow rate of the refrigerant in the first refrigerant jacket 51 can be increased.

[0055] In addition, according to the engine 100 of this embodiment, the engine 100 is equipped with a cylinder head 8, and the cylinder block 1 is equipped with a first head connecting passage 31 that supplies refrigerant from the first refrigerant jacket 51 to the cylinder head 8, so that the refrigerant can flow smoothly to the cylinder head 8.

[0056] Moreover, according to the engine 100 of this embodiment, the cylinder block 1 includes a communication recess 23C that is provided on the inner surface of the through hole 11 and that forms a communication passage 23 that communicates the first refrigerant jacket 51 and the second refrigerant jacket 52, and a first main refrigerant passage 21 that supplies refrigerant from a refrigerant supply source directly to the first refrigerant jacket 51 without passing through the second refrigerant jacket 52 and the communication passage 23. The cylinder head 8 includes one or more intake ports 81 and one or more exhaust ports 82. The first refrigerant jacket 51 includes a first main refrigerant passage 21 that supplies refrigerant directly from a refrigerant supply source to the first refrigerant jacket 51 without passing through the second refrigerant jacket 52 and the communication passage 23. The cooling recess 23C is provided in each of the intake side path 511 and the exhaust side path 512, and the distance from the communication path 23 provided in the exhaust side path 512 to the first head communication path 31 is longer than the distance from the communication path 23 provided in the intake side path 511 to the first head communication path 31. This configuration enhances the cooling performance of the exhaust side path 512 and suppresses overcooling of the intake side path 511.

[0057] The above embodiment may be modified as follows.

[0058] In the above embodiment, an example has been shown in which the end of the first recess 51C on the flange portion 44 side is connected to the end face of the flange portion 44 on the first recess 51C side, but an annular portion that fits into the through hole 11 may be provided between the first recess 51C and the flange portion 44. That is, the configuration of "the first recess 51C that is provided between the flange portion 44 and the first fitting portion 41 along the circumferential direction of the cylindrical portion 43 and forms an annular first refrigerant jacket 51 between the flange portion 44 and the inner surface of the through hole 11" also includes a configuration in which an annular portion that fits into the through hole 11 is provided between the first recess 51C and the flange portion 44.

[0059] In addition to the configuration according to the above embodiment, one or more communication passages 23 may be added to the exhaust-side path 512. With this configuration, the cooling performance of the exhaust-side path 512 can be improved.

[0060] In the configuration according to the above embodiment, the circumferential width of the exhaust-side communication passage 23 may be greater than the circumferential width of the intake-side communication passage 23. With this configuration, the cooling performance of the exhaust-side path 512 can be improved. [Explanation of symbols]

[0061] 100 Engine 1 Cylinder block 11 Through hole 21 First main refrigerant passage (main refrigerant passage) 23 Communication path 23C Connecting recess 31 First head communication passage (head communication passage) 4 Cylinder Liner 41 First fitting part 42 Second fitting part 43 Cylindrical section 44 Flange part 44E Lower end surface of flange (end surface of flange on the first recess side) 51 First refrigerant jacket 51C First recess 51E Upper end of the first recess (the end of the first recess on the flange side) 511 Air supply side route 512 Exhaust side route 52 Second refrigerant jacket 52C Second recess 8. Cylinder head 81 Air supply port 82 Exhaust port

Claims

1. A cylinder head, A cylinder block having a through hole; a cylinder liner provided in the through hole, The cylinder liner comprises: A flange portion having an outer diameter larger than that of the through hole; a first fitting portion and a second fitting portion that fit into the through hole; a first recess that forms a first refrigerant jacket along a circumferential direction between the flange portion and the first fitting portion; a second recess that forms a second refrigerant jacket between the first fitting portion and the second fitting portion; Equipped with The cylinder block includes: a head communication passage for supplying a refrigerant from the first refrigerant jacket to the cylinder head; a communication recess provided on an inner surface of the through hole to form a communication passage that communicates the first refrigerant jacket and the second refrigerant jacket, The cylinder head includes one or more air inlets and one or more exhaust ports. The communication recess is provided on each of the air intake port side and the air exhaust port side, an engine, characterized in that a distance from the communication passage provided on the exhaust port side to the head communication passage is longer than a distance from the communication passage provided on the intake port side to the head communication passage.

2. The cylinder block includes a main refrigerant passage that supplies the refrigerant from a refrigerant supply source directly to the first refrigerant jacket without passing through the second refrigerant jacket and the communication passage, The first refrigerant jacket is an intake side path extending from the main refrigerant passage to the head communication passage via a side where the intake port is unevenly located; an exhaust side path extending from the main refrigerant passage to the head communication passage via a side where the exhaust port is unevenly located, The communication recess is provided in each of the intake side path and the exhaust side path, 2. The engine according to claim 1, wherein a distance from the communication passage provided in the exhaust-side passage to the head communication passage is longer than a distance from the communication passage provided in the intake-side passage to the head communication passage.

3. 3. The engine according to claim 1, wherein an end of the first recess on the flange side is connected to an end face of the flange on the first recess side.

4. 4. The engine according to claim 1, wherein the first fitting portion has an annular shape without discontinuities over the entire circumferential area.

5. 5. The engine according to claim 1, wherein the communication recess has a flat shape whose width in the circumferential direction is greater than its width in the radial direction.

Images