阅读说明：本技术 内燃机 (Internal combustion engine ) 是由 多田博 于 2019-07-24 设计创作，主要内容包括：本发明提供一种更均匀地冷却内燃机的多个气缸的内燃机。气缸构造体具有直列配置的多个气缸。与气缸构造体的第1侧壁相对的冷却流路包括第1内侧流路和第1外侧流路。第1内侧流路配置成供注入的冷却介质中的第1冷却介质流动。第1外侧流路与第1内侧流路相比远离第1侧壁,并配置成供注入的冷却介质中的第2冷却介质流动。与气缸构造体的第2侧壁相对的冷却流路包括第2外侧流路和第2内侧流路。第2外侧流路的上游与第1外侧流路的下游连接。第2内侧流路与第2外侧流路相比靠近第2侧壁。多个连结流路将第2外侧流路与第2内侧流路之间连结,并设置于与多个缸分别相对的位置。(The invention provides an internal combustion engine which cools a plurality of cylinders of the internal combustion engine more uniformly. The cylinder structure has a plurality of cylinders arranged in series. The cooling flow path facing the 1 st side wall of the cylinder structure includes a 1 st inner flow path and a 1 st outer flow path. The 1 st inner flow path is configured to flow a 1 st cooling medium among the injected cooling media. The 1 st outer channel is located farther from the 1 st side wall than the 1 st inner channel, and is configured to allow the 2 nd cooling medium of the injected cooling media to flow. The cooling flow path facing the 2 nd side wall of the cylinder structure includes a 2 nd outer flow path and a 2 nd inner flow path. The upstream of the 2 nd outer flow path is connected to the downstream of the 1 st outer flow path. The 2 nd inner channel is closer to the 2 nd side wall than the 2 nd outer channel. The plurality of connecting passages connect the 2 nd outer passage and the 2 nd inner passage, and are provided at positions facing the plurality of cylinders, respectively.)

1. An internal combustion engine is provided with:

a cylinder structure having a plurality of cylinders arranged in series; and

a cooling flow path which is arranged around the side wall of the cylinder structure and through which a cooling medium flows,

the side walls of the cylinder structure include a 1 st side wall on one of an intake side and an exhaust side and a 2 nd side wall on the other of the intake side and the exhaust side,

the cooling flow path has:

an injection port into which the cooling medium is injected;

a 1 st inner channel facing the 1 st sidewall, having an upstream connected to the inlet, and configured to allow a 1 st cooling medium of the injected cooling media to flow;

a 1 st outer channel facing the 1 st sidewall, spaced apart from the 1 st sidewall more upstream than the 1 st inner channel, connected to the injection port, and configured to allow a 2 nd cooling medium of the injected cooling medium to flow;

a 2 nd outer channel facing the 2 nd side wall, having an upstream connected to a downstream of the 1 st outer channel, and configured to allow the 2 nd cooling medium to flow therethrough;

a 2 nd inner channel facing the 2 nd side wall and closer to the 2 nd side wall than the 2 nd outer channel; and

and a plurality of connection passages that connect the 2 nd outer passage and the 2 nd inner passage and are provided at positions facing the respective cylinders.

2. The internal combustion engine according to claim 1,

the cross-sectional areas of the plurality of connecting passages increase from the upstream to the downstream of the 2 nd outer passage.

3. The internal combustion engine according to claim 1 or 2,

the cylinder structure and the cooling flow path are disposed in the cylinder block,

the 1 st inner flow path is disposed so that the 1 st cooling medium is discharged to the outside of the cylinder block without merging with the 2 nd cooling medium.

4. An internal combustion engine according to any one of claims 1 to 3,

the cross-sectional area of the 1 st inner flow path decreases from the upstream side to the downstream side of the 1 st inner flow path.

5. The internal combustion engine according to any one of claims 1 to 4,

the cooling flow path further has an inter-cylinder flow path arranged between adjacent cylinders of the plurality of cylinders,

the inter-cylinder flow passage is connected to the 2 nd outer flow passage.

Technical Field

The present invention relates to an internal combustion engine including a cooling flow path for cooling a plurality of cylinders.

Background

Patent document 1 discloses a structure of a water jacket of an internal combustion engine. The cooling water in the water jacket flows along the plurality of cylinders in sequence. The upstream portion of the water jacket is separated into an upper flow path and a lower flow path. The upper cooling water flowing through the upper flow path directly cools the outer walls of the plurality of cylinders. On the other hand, the lower cooling water flowing through the lower flow path does not contact the outer walls of the plurality of cylinders. Therefore, the temperature rise of the lower cooling water can be suppressed. The lower cooling water is guided to the upper flow path by the upper guide member, and merges with the upper cooling water. This enables the plurality of cylinders to be sufficiently cooled even in the downstream portion of the water jacket.

Disclosure of Invention

Problems to be solved by the invention

According to the technique disclosed in patent document 1, the temperature of the cooling water in the water jacket (cooling flow path) increases from upstream to downstream. That is, the cooling performance decreases from upstream toward downstream. Since the lower cooling water and the upper cooling water are merged, the cooling performance is temporarily recovered, but the cooling performance is not reduced as it goes downstream. When the cooling performance decreases toward the downstream, the cooling effect on the plurality of cylinders becomes uneven. This causes temperature deviation among a plurality of cylinders, and is therefore not preferable.

An object of the present invention is to provide a technique for cooling a plurality of cylinders more uniformly in an internal combustion engine provided with a cooling flow path for cooling the plurality of cylinders.

Means for solving the problems

Viewpoint 1 provides an internal combustion engine.

The internal combustion engine is provided with:

a cylinder structure having a plurality of cylinders arranged in series; and

and a cooling flow path that is disposed around the side wall of the cylinder structure and through which a cooling medium flows.

The side walls of the cylinder structure include a 1 st side wall on one of an intake side and an exhaust side and a 2 nd side wall on the other of the intake side and the exhaust side.

The cooling flow path has:

an injection port into which the cooling medium is injected;

a 1 st inner channel facing the 1 st sidewall, having an upstream connected to the inlet, and configured to allow a 1 st cooling medium of the injected cooling media to flow;

a 1 st outer channel facing the 1 st sidewall, spaced apart from the 1 st sidewall more upstream than the 1 st inner channel, connected to the injection port, and configured to allow a 2 nd cooling medium of the injected cooling medium to flow;

a 2 nd outer channel facing the 2 nd side wall, having an upstream connected to a downstream of the 1 st outer channel, and configured to allow the 2 nd cooling medium to flow therethrough;

a 2 nd inner channel facing the 2 nd side wall and closer to the 2 nd side wall than the 2 nd outer channel; and

and a plurality of connection passages that connect the 2 nd outer passage and the 2 nd inner passage and are provided at positions facing the respective cylinders.

The viewpoint 2 has the following features in addition to the viewpoint 1.

The cross-sectional areas of the plurality of connecting passages increase from the upstream to the downstream of the 2 nd outer passage.

The aspect 3 has the following features in addition to the aspect 1 or 2.

The cylinder structure and the cooling flow path are disposed in the cylinder block.

The 1 st inner flow path is disposed so that the 1 st cooling medium is discharged to the outside of the cylinder block without merging with the 2 nd cooling medium.

The 4 th aspect has the following features in addition to any one of the 1 st to 3 rd aspects.

The cross-sectional area of the 1 st inner flow path decreases from the upstream side to the downstream side of the 1 st inner flow path.

The aspect 5 has the following features in addition to any one of the aspects 1 to 4.

The cooling flow path further includes an inter-cylinder flow path arranged between adjacent cylinders of the plurality of cylinders.

The inter-cylinder flow passage is connected to the 2 nd outer flow passage.

Effects of the invention

According to the 1 st aspect, the cooling flow path facing the 1 st side wall of the cylinder structure includes the 1 st inner flow path and the 1 st outer flow path. The 1 st side wall side cylinder structure is efficiently cooled by the 1 st cooling medium flowing through the 1 st inner flow path. On the other hand, since the 1 st outer channel is separated from the 1 st side wall as compared with the 1 st inner channel, the cooling performance of the 2 nd cooling medium flowing through the 1 st outer channel is maintained without being lowered.

The cooling flow path facing the 2 nd side wall of the cylinder structure includes a 2 nd inner flow path and a 2 nd outer flow path. The upstream of the 2 nd outer flow path is connected to the downstream of the 1 st outer flow path. Therefore, the 2 nd cooling medium having high cooling performance flows from the 1 st outer flow path into the 2 nd outer flow path. The 2 nd outer channel is located farther from the 2 nd side wall than the 2 nd inner channel. Therefore, the high cooling performance of the 2 nd cooling medium can be maintained also in the 2 nd outer flow path.

The connecting channel connects the 2 nd inner channel and the 2 nd outer channel. The 2 nd cooling medium in the 2 nd outer flow path is supplied to the 2 nd inner flow path through the connection flow path. The cylinder structure on the 2 nd side wall side is also efficiently cooled by the 2 nd cooling medium having high cooling performance.

The plurality of connecting flow paths are provided at positions facing the plurality of cylinders of the cylinder structure, respectively. Therefore, the 2 nd cooling medium is supplied in parallel to the 2 nd inner flow path at the position of each of the plurality of cylinders through each of the plurality of connecting flow paths. This enables the plurality of cylinders to be cooled more uniformly than in the case where the 2 nd cooling medium flows along the plurality of cylinders in sequence in the 2 nd inner flow path. As a result, temperature variation among the plurality of cylinders can be suppressed.

According to the 2 nd aspect, the cross-sectional areas of the plurality of connected channels increase from the upstream side to the downstream side of the 2 nd outer channel. On the other hand, the pressure of the 2 nd cooling medium in the 2 nd outer flow path decreases from upstream toward downstream. Therefore, the flow rate of the 2 nd cooling medium passing through each of the plurality of connecting passages is equalized, and the plurality of cylinders can be cooled more uniformly.

According to the 3 rd aspect, the 1 st inner flow path is arranged such that the 1 st cooling medium is discharged to the outside of the cylinder block without merging with the 2 nd cooling medium. Since the 1 st cooling medium whose cooling performance has been reduced does not merge with the 2 nd cooling medium, a reduction in the cooling performance of the 2 nd cooling medium can be suppressed.

According to the 4 th aspect, the cross-sectional area of the 1 st inner flow path becomes smaller from the upstream side toward the downstream side of the 1 st inner flow path. Thus, the flow velocity of the 1 st cooling medium increases from the upstream side to the downstream side of the 1 st inner channel. On the other hand, the temperature of the 1 st cooling medium increases from the upstream side to the downstream side of the 1 st inner channel. The increase in cooling performance due to the increase in flow rate eliminates the decrease in cooling performance due to the increase in temperature. This enables the plurality of cylinders to be cooled more uniformly on the 1 st sidewall side.

According to the 5 th aspect, the inter-cylinder flow path arranged between the adjacent cylinders is connected to the 2 nd outer flow path. Thereby, the 2 nd cooling medium having high cooling performance is supplied from the 2 nd outer flow passage to the inter-cylinder flow passage. The portion between the adjacent cylinders is efficiently cooled by the 2 nd cooling medium having high cooling performance.

Drawings

Fig. 1 is a schematic diagram showing the structure of an internal combustion engine according to embodiment 1 of the present invention.

Fig. 2 is a schematic diagram for explaining a cylinder structure and a cooling flow passage according to embodiment 1 of the present invention.

Fig. 3 is a schematic view of a side wall of a cylinder structure for explaining embodiment 1 of the present invention.

Fig. 4 is a schematic diagram for explaining the structure of the cooling flow path on the 1 st side wall side of the cylinder structure according to embodiment 1 of the present invention.

Fig. 5 is a sectional view for explaining the structure of the cooling flow path on the 1 st side wall side of the cylinder structure according to embodiment 1 of the present invention.

Fig. 6 is a schematic diagram for explaining the structure of the cooling flow path on the 2 nd side wall side of the cylinder structure according to embodiment 1 of the present invention.

Fig. 7 is a sectional view for explaining the structure of the cooling flow path on the 2 nd side wall side of the cylinder structure according to embodiment 1 of the present invention.

Fig. 8 is a sectional view for explaining the structure of the cooling flow path on the 2 nd side wall side of the cylinder structure according to embodiment 1 of the present invention.

Fig. 9 is a sectional view for explaining the structure of the cooling flow path according to embodiment 2 of the present invention.

Fig. 10 is a schematic diagram for explaining the structure of the cooling flow path according to embodiment 3 of the present invention.

Detailed Description

Embodiments of the present invention will be described with reference to the accompanying drawings.

1. Embodiment 1

1-1. schematic structure

Fig. 1 is a schematic diagram showing the structure of an internal combustion engine 1 according to embodiment 1. The internal combustion engine 1 includes a cylinder 10 and a cooling flow path 100 for cooling the cylinder 10.

A cylinder 10 (combustion chamber) is formed in the cylinder block 20. More specifically, a cylindrical cylinder liner 21 (cylinder bore) forms the inner surface of the cylinder 10. The piston 30 is disposed so as to reciprocate in the axial direction of the cylinder 10. The upper surface of the piston 30 forms the bottom surface of the cylinder 10. A cylinder head 40 is provided on the cylinder block 20. The bottom surface of the cylinder head 40 forms the upper surface of the cylinder 10.

The intake port 50 supplies intake gas to the cylinder 10. The exhaust port 60 discharges exhaust gas from the cylinder 10. The intake port 50 and the exhaust port 60 are formed in the cylinder head 40. An intake valve 51 is provided in an opening portion of the intake port 50 with respect to the cylinder 10. An exhaust valve 61 is provided in an opening portion of the exhaust port 60 with respect to the cylinder 10.

A cooling flow path 100 (water jacket) is formed around the cylinder 10 in the cylinder block 20. A cooling medium (e.g., cooling water) flows through the cooling flow path 100, thereby cooling the cylinder 10.

Fig. 2 is a schematic diagram for explaining the cylinder structure 10X and the cooling flow path 100 according to the present embodiment. The cylinder structure 10X is an assembly of a plurality of cylinders 10-i (i is an integer of 2 or more). In the example shown in FIG. 2, the cylinder structure 10X has a plurality of cylinders 10-1 to 10-3. These plurality of cylinders 10-i are arranged in series in one direction.

In the following description, the "X direction" is a direction in which the plurality of cylinders 10-i are arranged. The "Z direction" is the moving direction of the piston 30. The X direction is orthogonal to the Z direction. The "Y direction" is a direction orthogonal to the X direction and the Z direction. The "upward direction" is a direction in which the piston 30 rises, i.e., a direction from the cylinder block 20 toward the cylinder head 40. The "lower direction" is a direction opposite to the upper direction.

As shown in fig. 2, the cylinder block 20 includes a cylinder structure 10X and a cooling flow path 100. The cooling flow path 100 is disposed around the side wall of the cylinder structure 10X. The cooling medium flows through the cooling flow path 100, thereby cooling the cylinder structure 10X (the plurality of cylinders 10-i).

The structure (configuration) of the cooling flow path 100 can be adjusted by using the water jacket spacer 200 shown in fig. 2. Specifically, the water jacket spacer 200 is inserted into the cooling flow path 100 when the internal combustion engine 1 is assembled. Thereby, the cooling flow path 100 having a desired structure is obtained.

The structure of the cooling flow path 100 of the present embodiment will be described in detail below.

1-2. Structure of Cooling flow Path

To explain the structure of the cooling flow path 100, first, the side wall of the cylinder structure 10X is explained with reference to fig. 3. The side walls of the cylinder structure 10X include a 1 st side wall 11 and a 2 nd side wall 12. The 1 st side wall 11 is a side wall on one of the intake side (intake port 50 side) and the exhaust side (exhaust port 60 side). The 2 nd side wall 12 is the side wall on the other of the intake side and the exhaust side. In the example shown in fig. 3, the 1 st side wall 11 is a side wall on the exhaust side, and the 2 nd side wall 12 is a side wall on the intake side.

Fig. 4 and 5 are a schematic diagram and a cross-sectional view, respectively, for explaining the structure of the cooling channel 100 on the 1 st side wall 11 side. The cooling channel 100 on the 1 st side wall 11 side includes a "1 st inner channel 110A" and a "1 st outer channel 110B". The 1 st inner channel 110A and the 1 st outer channel 110B are both opposed to the 1 st side wall 11.

The 1 st inner channel 110A is separated from the 1 st outer channel 110B in the Z direction. More specifically, the 1 st inner flow path 110A is disposed on the upper side, and the 1 st outer flow path 110B is disposed on the lower side. In order to perform such flow passage separation, the water jacket spacer 200 may also have a 1 st separating member 210 as shown in fig. 5. The 1 st separating member 210 is interposed between the 1 st side wall 11 and the cylinder block 20, and divides the cooling passage 100 on the 1 st side wall 11 side into a 1 st inner passage 110A and a 1 st outer passage 110B.

As shown in fig. 5, the 1 st outer channel 110B is separated from the 1 st side wall 11 as compared with the 1 st inner channel 110A. In contrast, the 1 st inner channel 110A is closer to the 1 st side wall 11 than the 1 st outer channel 110B. For example, the 1 st inner channel 110A contacts the 1 st sidewall 11, and the 1 st outer channel 110B does not contact the 1 st sidewall 11. In order to form such a 1 st outer side flow passage 110B, the water jacket spacer 200 may also have a 1 st spacing member 215 shown in fig. 5. The 1 st spacing member 215 is formed to be in contact with the 1 st sidewall 11. The 1 st outer channel 110B separated from the 1 st side wall 11 is formed by the 1 st partition member 215.

The cooling flow path 100 has an inlet (inlet)101 (see fig. 4) into which a cooling medium C (cooling water, for example) is injected. The injection port 101 is connected to the upstream of both the 1 st inner channel 110A and the 1 st outer channel 110B. The cooling medium C injected into the cooling channel 100 through the injection port 101 is distributed to the 1 st inner channel 110A and the 1 st outer channel 110B. The cooling medium C distributed to the 1 st inner channel 110A is hereinafter referred to as "1 st cooling medium CA". On the other hand, the cooling medium C distributed to the 1 st outer channel 110B is hereinafter referred to as "2 nd cooling medium CB".

The 1 st cooling medium CA flows through the 1 st inner channel 110A. The direction from the upstream to the downstream of the 1 st inner passage 110A is the direction from the cylinder 10-1 to the cylinder 10-3, and the main component thereof is the X direction. In other words, the 1 st inner channel 110A is arranged such that the 1 st cooling medium CA flows sequentially along the plurality of cylinders 10-1, 10-2, and 10-3.

The 1 st inner flow path 110A is disposed so that the 1 st cooling medium CA is discharged to the outside of the cylinder block 20 without merging with the 2 nd cooling medium CB. For example, as shown in fig. 4, the downstream of the 1 st inner channel 110A is connected to an outlet (outlet) 102. The discharge port 102 is connected to the outside of the cylinder block 20, typically the cylinder head 40. The water jacket spacer 200 may also have a partition member 202 shown in fig. 4. The partition member 202 is located downstream of the 1 st inner channel 110A, and prevents the 1 st cooling medium CA from spreading toward the 2 nd side wall 12.

The 1 st cooling medium CA flowing through the 1 st inner channel 110A effectively cools the 1 st side wall 11 side cylinder structure 10X. In particular, the temperature of the upper portion of the cylinder structure 10X (cylinder 10) is high, and such high-temperature portion is efficiently cooled by the 1 st cooling medium CA. The temperature of the 1 st cooling medium CA increases as it goes downstream of the 1 st inner channel 110A. The 1 st cooling medium CA having a lowered cooling performance is discharged to the outside of the cylinder block 20 through the discharge port 102 without merging with the 2 nd cooling medium CB.

On the other hand, the 2 nd cooling medium CB flows through the 1 st outer flow path 110B. The direction from the upstream toward the downstream of the 1 st outer flow path 110B is the direction from the cylinder 10-1 toward the cylinder 10-3, and the main component thereof is the X direction. In other words, the 1 st outer flow path 110B is arranged such that the 2 nd cooling medium CB flows sequentially along the plurality of cylinders 10-1, 10-2, and 10-3.

Note that the 1 st outer channel 110B is separated from the 1 st side wall 11 (see fig. 5) than the 1 st inner channel 110A. Although both the 1 st cooling medium CA and the 2 nd cooling medium CB flow in the vicinity of the 1 st side wall 11, the temperature of the 2 nd cooling medium CB does not rise as much as the 1 st cooling medium CA. The temperature of the 2 nd cooling medium CB flowing through the 1 st outer channel 110B is lower than the temperature of the 1 st cooling medium CA flowing through the 1 st inner channel 110A. That is, the cooling performance of the 2 nd cooling medium CB is maintained without being lowered. The 2 nd cooling medium CB having such high cooling performance is used for cooling the cylinder structure 10X on the 2 nd side wall 12 side.

Fig. 6 and 7 are a schematic diagram and a cross-sectional view, respectively, for explaining the structure of the cooling channel 100 on the 2 nd side wall 12 side. The cooling channel 100 on the 2 nd side wall 12 side includes the "2 nd inner channel 120A" and the "2 nd outer channel 120B". The 2 nd inner channel 120A and the 2 nd outer channel 120B are both opposed to the 2 nd side wall 12.

The 2 nd inner channel 120A and the 2 nd outer channel 120B are separated in the Z direction. More specifically, the 2 nd inner flow path 120A is disposed on the upper side, and the 2 nd outer flow path 120B is disposed on the lower side. In order to perform such flow passage separation, the water jacket spacer 200 may also have a 2 nd separating member 220 as shown in fig. 7. The 2 nd separating member 220 is interposed between the 2 nd side wall 12 and the cylinder block 20, and divides the cooling passage 100 on the 2 nd side wall 12 side into a 2 nd inner passage 120A and a 2 nd outer passage 120B.

As shown in fig. 7, the 2 nd outer channel 120B is separated from the 2 nd side wall 12 as compared with the 2 nd inner channel 120A. In contrast, the 2 nd inner channel 120A is closer to the 2 nd side wall 12 than the 2 nd outer channel 120B. For example, the 2 nd inner channel 120A contacts the 2 nd sidewall 12, and the 2 nd outer channel 120B does not contact the 2 nd sidewall 12. In order to form such a 2 nd outer flow passage 120B, the water jacket spacer 200 may also have a 2 nd spacing member 225 as shown in fig. 7. The 2 nd spacing member 225 is formed to be in contact with the 2 nd sidewall 12. The 2 nd outer channel 120B separated from the 2 nd side wall 12 is formed by the 2 nd partition member 225.

As shown in fig. 6, the upstream of the 2 nd outer channel 120B is connected to the downstream of the 1 st outer channel 110B. As a result, the 2 nd cooling medium CB flows from the 1 st outer channel 110B into the 2 nd outer channel 120B. The direction from the upstream toward the downstream of the 2 nd outer flow path 120B is the direction from the cylinder 10-3 toward the cylinder 10-1, and the main component thereof is the-X direction. In other words, the 2 nd outer flow path 120B is arranged such that the 2 nd cooling medium CB flows in sequence along the plurality of cylinders 10-3, 10-2, and 10-1.

The cooling channel 100 of the present embodiment further includes a "connection channel 130" that connects the 2 nd inner channel 120A and the 2 nd outer channel 120B. Fig. 8 is a sectional view of the position of the connection flow path 130. As shown in fig. 8, the connection channel 130 is implemented by, for example, a through hole penetrating the No. 2 separating member 220. The 2 nd cooling medium CB in the 2 nd outer channel 120B is supplied to the 2 nd inner channel 120A through the connecting channel 130.

As described above, the 2 nd outer channel 120B is separated from the 2 nd side wall 12 than the 2 nd inner channel 120A. Therefore, the temperature of the 2 nd cooling medium CB does not increase so much in the 2 nd outer flow path 120B, and the high cooling performance of the 2 nd cooling medium CB is maintained. The 2 nd cooling medium CB having high cooling performance is supplied to the 2 nd inner flow path 120A through the coupling flow path 130. The cylinder structure 10X on the 2 nd side wall 12 side is efficiently cooled by the 2 nd cooling medium CB having high cooling performance. In particular, the temperature of the upper portion of the cylinder structure 10X (cylinder 10) is high, and such high-temperature portion is efficiently cooled by the 2 nd cooling medium CB.

In addition, as shown in FIG. 6, according to the present embodiment, a plurality of connecting passages 130-i are provided at positions respectively opposed to the plurality of cylinders 10-i. Therefore, the 2 nd cooling medium CB is supplied in parallel to the 2 nd inner passage 120A at the position of each of the plurality of cylinders 10-i through each of the plurality of link passages 130-i. This enables the plurality of cylinders 10-i to be cooled more uniformly than in the case where the 2 nd cooling medium CB flows in the 2 nd inner passage 120A sequentially along the plurality of cylinders 10-i. As a result, temperature variations among the plurality of cylinders 10-i can be suppressed.

The cooling effect on the cylinder 10-i also depends on the flow rate of the 2 nd cooling medium CB through the junction flow path 130-i. Therefore, the cooling effect on the cylinder 10-i can also be adjusted by adjusting the cross-sectional area of the connecting passage 130-i (the cross-sectional area perpendicular to the flow direction of the 2 nd cooling medium CB).

For example, the pressure of the 2 nd cooling medium CB in the 2 nd outer flow path 120B decreases from upstream toward downstream. Therefore, the cross-sectional areas of the plurality of connecting channels 130-i may be designed to increase from the upstream side to the downstream side of the 2 nd outer channel 120B. This equalizes the flow rate of the 2 nd cooling medium CB passing through each of the plurality of connecting passages 130-i, and enables the plurality of cylinders 10-i to be cooled more uniformly.

The 2 nd cooling medium CB in the 2 nd inner channel 120A is appropriately discharged through a discharge port not shown.

1-3 summary of

The cooling flow path 100 facing the 1 st side wall 11 of the cylinder structure 10X includes a 1 st inner flow path 110A and a 1 st outer flow path 110B. The 1 st cooling medium CA flowing through the 1 st inner channel 110A effectively cools the 1 st side wall 11 side cylinder structure 10X. On the other hand, since the 1 st outer channel 110B is separated from the 1 st side wall 11 as compared with the 1 st inner channel 110A, the cooling performance of the 2 nd cooling medium CB flowing through the 1 st outer channel 110B is maintained without being lowered.

The cooling flow path 100 facing the 2 nd side wall 12 of the cylinder structure 10X includes a 2 nd inner flow path 120A and a 2 nd outer flow path 120B. The upstream side of the 2 nd outer flow path 120B is connected to the downstream side of the 1 st outer flow path 110B. Therefore, the 2 nd cooling medium CB having high cooling performance flows from the 1 st outer flow path 110B into the 2 nd outer flow path 120B. The 2 nd outer channel 120B is located farther from the 2 nd side wall 12 than the 2 nd inner channel 120A. Therefore, the high cooling performance of the 2 nd cooling medium CB is maintained also in the 2 nd outer flow path 120B.

The connecting channel 130 connects the 2 nd inner channel 120A and the 2 nd outer channel 120B. The 2 nd cooling medium CB in the 2 nd outer channel 120B is supplied to the 2 nd inner channel 120A through the connecting channel 130. The cylinder structure 10X on the 2 nd side wall 12 side is also efficiently cooled by the 2 nd cooling medium CB having high cooling performance.

The plurality of connecting passages 130-i are provided at positions facing the plurality of cylinders 10-i of the cylinder structure 10X, respectively. Therefore, the 2 nd cooling medium CB is supplied in parallel to the 2 nd inner passage 120A at the position of each of the plurality of cylinders 10-i through each of the plurality of link passages 130-i. This enables the plurality of cylinders 10-i to be cooled more uniformly than in the case where the 2 nd cooling medium CB flows in the 2 nd inner passage 120A sequentially along the plurality of cylinders 10-i. As a result, temperature variations among the plurality of cylinders 10-i can be suppressed.

The cooling effect on the cylinder 10-i also depends on the flow rate of the 2 nd cooling medium CB through the junction flow path 130-i. The pressure of the 2 nd cooling medium CB in the 2 nd outer flow path 120B decreases from upstream toward downstream. Therefore, the cross-sectional area of the plurality of connecting channels 130-i may be increased from the upstream side to the downstream side of the 2 nd outer channel 120B. This equalizes the flow rate of the 2 nd cooling medium CB passing through each of the plurality of connecting passages 130-i, and enables the plurality of cylinders 10-i to be cooled more uniformly.

The 1 st inner flow path 110A is disposed so that the 1 st cooling medium CA is discharged to the outside of the cylinder block 20 without merging with the 2 nd cooling medium CB. Since the 1 st cooling medium CA having a lowered cooling performance does not merge with the 2 nd cooling medium CB, a lowering of the cooling performance of the 2 nd cooling medium CB can be suppressed.

2. Embodiment 2

Fig. 9 is a sectional view for explaining the structure of the cooling flow path 100 according to embodiment 2. In particular, fig. 9 shows the cross-sectional structure of the cooling channel 100 on the 1 st side wall 11 side, as in fig. 5 of embodiment 1. The description overlapping with embodiment 1 is appropriately omitted.

According to embodiment 2, the cross-sectional area of the 1 st inner channel 110A (cross-sectional area perpendicular to the flow direction of the 1 st cooling medium CA) is smaller than that of embodiment 1 shown in fig. 5. For example, the water jacket spacer 200 has a narrow member 230 as shown in fig. 9. By disposing the narrowing member 230 in the 1 st inner channel 110A, the cross-sectional area of the 1 st inner channel 110A is reduced.

Since the cross-sectional area of the 1 st inner channel 110A is reduced, the flow velocity of the 1 st cooling medium CA flowing through the 1 st inner channel 110A increases, and the cooling performance of the 1 st cooling medium CA improves. This enables the cylinder structure 10X on the 1 st side wall 11 side to be cooled more efficiently.

The temperature of the 1 st cooling medium CA increases from the upstream side to the downstream side of the 1 st inner passage 110A. In consideration of the decrease in cooling performance due to this temperature increase, the cross-sectional area of the 1 st inner flow path 110A may also become smaller from the upstream toward the downstream of the 1 st inner flow path 110A (which is equivalent to the narrowing member 230 becoming thicker from the upstream toward the downstream of the 1 st inner flow path 110A). In this case, the flow velocity of the 1 st cooling medium CA increases from the upstream of the 1 st inner channel 110A toward the downstream. The increase in cooling performance due to the increase in flow rate eliminates the decrease in cooling performance due to the increase in temperature. Therefore, the plurality of cylinders 10-i can be cooled more uniformly also on the 1 st side wall 11 side. As a result, temperature variations among the plurality of cylinders 10-i can be suppressed.

3. Embodiment 3

Fig. 10 is a schematic diagram for explaining the structure of the cooling flow path 100 according to embodiment 3. In particular, fig. 10 shows the structure of the cooling channel 100 on the 2 nd side wall 12 side, as in fig. 6 in embodiment 1. The description overlapping with embodiment 1 is appropriately omitted.

As shown in fig. 10, the cooling flow path 100 further has an inter-cylinder flow path 140 (drilling path) disposed between the adjacent cylinders 10. The inter-cylinder flow path 140 is provided to cool a portion between the adjacent cylinders 10. The inter-cylinder flow path 140 is connected to the 2 nd outer flow path 120B via a connection port 150. As a result, the 2 nd cooling medium CB having high cooling performance is supplied from the 2 nd outer flow path 120B to the inter-cylinder flow path 140. The portion between the adjacent cylinders 10 is efficiently cooled by the 2 nd cooling medium CB having high cooling performance.

In addition, embodiment 2 and embodiment 3 may be combined.

Description of the reference numerals

1 internal combustion engine

10 air cylinder

10X cylinder structure

11 st side wall

12 nd 2 nd side wall

20 cylinder block

30 piston

100 cooling flow path

101 injection port

102 discharge port

110A 1 st inner channel

110B 1 st outer channel

120A 2 nd inner channel

120B 2 nd outer flow path

130 connecting flow path

140 flow path between cylinders

150 connecting port

200 water jacket spacer

202 partition member

210 st separation member

215 No. 1 spacing member

220 nd 2 nd separating member

225 nd spacer member

230 stenosed member

CA 1 st cooling medium

CB 2 nd cooling medium