Cooling structure of internal combustion engine

Abstract

A cooling structure for an internal combustion engine, comprising: a water jacket that surrounds the periphery of the bore diameter of the internal combustion engine and is formed inside the cylinder block and the cylinder head; a spacer disposed inside the water jacket; and a first inlet that introduces a refrigerant into the water jacket on the cylinder block side. The spacer has a weir portion on the cylinder head side of the first inlet and ribs erected on the weir portion.

Description

Technical Field

[0001] The present invention relates to a cooling structure for an internal combustion engine in which a water jacket is formed inside a cylinder block and a cylinder head. Background Art

[0002] Conventionally, a known technique is to insert a spacer into the water jacket formed around the cylinder bore of an internal combustion engine to control the flow of a refrigerant (e.g., engine coolant). For example, a cooling structure has been proposed that adjusts the flow direction and flow rate of the refrigerant in the water jacket using a spacer and cools a plurality of cylinder bores uniformly (see Patent Documents 1 and 2).

[0003] Patent Documents

[0004] [Patent Document 1] Japanese Patent No. 6315022

[0005] [Patent Document 2] Japanese Patent No. 6052134 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] On the one hand, depending on the position of the inlet for introducing the refrigerant into the water jacket and the shape of the water jacket, the flow of the refrigerant may deviate. For example, most of the refrigerant introduced into the water jacket on the cylinder block side may flow directly out to the cylinder head side, which may reduce the cooling efficiency of the cylinder bore.

[0008] One object of the present case is to provide a cooling structure for an internal combustion engine that is designed to address the above problems and can improve the cooling efficiency of the refrigerant with a simple structure. It should be noted that, without being limited to this object, the functions and effects derived from the respective structures shown in the "Embodiments" described later, which are functions and effects that cannot be obtained in the prior art, can also be regarded as other objects of the present case.

[0009] Technical Means for Solving the Problem

[0010] The disclosed cooling structure for an internal combustion engine includes: a water jacket that surrounds the cylinder bore of the internal combustion engine and is formed inside the cylinder block and the cylinder head; a spacer that is disposed inside the water jacket; and a first inlet that introduces the refrigerant into the water jacket on the cylinder block side. The spacer is provided with a weir portion on the cylinder head side of the first inlet and ribs erected on the weir portion.

[0011] Advantageous Effects of the Invention

[0012] According to the disclosed cooling structure for an internal combustion engine, the cooling efficiency of the refrigerant can be improved with a simple structure. Brief Description of the Drawings

[0013] Figure 1It is an exploded perspective view of an internal combustion engine to which a cooling structure is applied as an embodiment.

[0014] Figure 2 It is Figure 1 a top view of the spacer shown.

[0015] Figure 3 It is a schematic view that magnifies and shows Figure 2 the main part of the spacer shown.

[0016] Figure 4 It is Figure 1 a perspective view of the spacer shown.

[0017] Figure 5 It is Figure 1 a perspective view of the spacer shown.

[0018]

Symbol Explanation

[0019] 1: Internal combustion engine

[0020] 2: Cylinder block

[0021] 2a: Top surface

[0022] 3: Cylinder head

[0023] 4: Bore diameter

[0024] 5: Ceiling surface part

[0025] 6: Water jacket

[0026] 7: Water jacket

[0027] 8: Gasket

[0028] 9: Inlet part

[0029] 10: Spacer

[0030] 11: Exhaust side spacer

[0031] 12: Intake side spacer

[0032] 13: Weir part

[0033] 14: Rib

[0034] 15: Wall part

[0035] 16: Platform part

[0036] 21: First inlet

[0037] 22: Second inlet

[0038] 31: Through hole

[0039] 32: Communication hole Detailed Implementation Manner

[0040] [1. Constitution]

[0041] Figure 1 It is a schematic exploded perspective view for explaining the constitution of an internal combustion engine 1 to which a cooling structure is applied as an example. The internal combustion engine 1 is an engine such as a gasoline engine or a diesel engine (in this example, a four-cylinder engine), and is installed in the engine compartment of a vehicle.

[0042] The internal combustion engine 1 includes a cylinder block 2 and a cylinder head 3 fixed to the cylinder block 2. A plurality of (in this example, 4) cylindrical bores 4 with combustion chambers inside are formed side by side on the cylinder block 2. A ceiling surface portion 5 that constitutes the upper surface of the combustion chamber is formed on the cylinder head 3. The shape of the bore 4 is, for example, cylindrical, and the shape of the ceiling surface portion 5 is, for example, conical. An intake port and an exhaust port (not shown) are connected to the ceiling surface portion 5. A gasket 8 is sandwiched between the cylinder block 2 and the cylinder head 3.

[0043] The gasket 8 has the function of ensuring the airtightness of each cylinder and the liquid tightness of the coolant and lubricating oil. The gasket 8 is provided with a plurality of through holes 31 perforated at positions corresponding to the respective bores 4 and a plurality of communication holes 32 perforated around each through hole 31 and smaller than the through holes 31. The plurality of through holes 31 connect the bore 4 and the ceiling surface portion 5. As described below, the plurality of communication holes 32 connect the water jacket 6 provided in the cylinder block 2 and the water jacket 7 provided in the cylinder head 3.

[0044] A water jacket 6 surrounding the periphery of the bore 4 is formed on the cylinder block 2. The water jacket 6 has a shape that is open to the upper surface side of the cylinder block 2 (the side where the cylinder head 3 is arranged).

[0045] In addition, a water jacket 7 surrounding the periphery of the ceiling surface portion 5 and the intake port, exhaust port, etc. (not shown) is formed on the cylinder head 3. The water jacket 7 has a shape that is open to the lower surface side of the cylinder head 3 (the side arranged on the cylinder block 2).

[0046] A refrigerant (for example, engine coolant) circulates inside the water jackets 6 and 7, and the cylinder block 2 and the cylinder head 3 are cooled by the refrigerant. In addition, the water jacket 6 on the cylinder block 2 side is connected to the water jacket 7 on the cylinder head 3 side through a plurality of communication holes 32 perforated in the gasket 8.

[0047] As Figure 2 shown, an inlet portion 9 that is an inlet for the refrigerant of the water jacket 6 is provided on the intake side of the cylinder block 2. It should be noted that the intake side is the side where the intake port and the intake manifold are arranged when viewed from above, and is the side indicated by the symbol A in Figure 1 and Figure 2 . In addition, the exhaust side is the side where the exhaust port and the exhaust manifold are arranged when viewed from above, and is the side indicated by the symbol B in Figure 1 and Figure 2 .

[0048] The inlet portion 9 is a portion where the water jacket 6 is formed in a shape that expands in the expanding direction of the cylinder diameter 4. As Figure 2 shown, the position of the inlet portion 9 is arranged on the suction side A of the cylinder diameter 4, and the suction side A is located at the end of a plurality of arranged cylinder diameters 4.

[0049] A first inlet 21 connecting the outer circumferential surface of the cylinder block 2 and the inlet portion 9 is provided on the cylinder block 2. The first inlet 21 is a portion that serves as a passage for introducing the refrigerant into the water jacket 6 on the cylinder block 2 side. As Figure 1 shown, the position of the first inlet 21 is provided at a position spaced downward from the top surface 2a of the cylinder block 2. In addition, among the communication holes 32 perforated in the gasket 8, the communication hole 32 arranged directly above the inlet portion 9 is called a second inlet 22. The second inlet 22 is a communication hole 32 that connects the water jacket 6 on the cylinder block 2 side and the water jacket 7 on the cylinder head 3 side, and is arranged at a position overlapping the inlet portion 9 when viewed from above.

[0050] It should be noted that the second inlet 22 that connects the water jacket 6 on the cylinder block 2 side and the water jacket 7 on the cylinder head 3 side includes holes or openings other than the communication holes 32 perforated in the gasket 8. For example, a passage that connects these is formed in the cylinder block 2 and the cylinder head 3, and the joint portion of this passage is also called the second inlet 22. Therefore, the second inlet 22 is not necessarily formed on the gasket 8. In other words, the second inlet 22 may also exist in the internal combustion engine 1 without the gasket 8.

[0051] A spacer 10 as a component for controlling the flow of the refrigerant is arranged inside the water jacket 6. Figure 1 The internal combustion engine 1 shown is provided with a spacer 10 having an exhaust side spacer 11 and a suction side spacer 12. The exhaust side spacer 11 is a spacer inserted into the water jacket 6 closer to the exhaust side B than the cylinder diameter 4. The suction side spacer 12 is a spacer inserted into the water jacket 6 closer to the suction side A than the cylinder diameter 4. The approximate shapes of the exhaust side spacer 11 and the suction side spacer 12 are curved surface shapes corresponding to the internal shape of the water jacket 6, and when viewed from above, they conform to a shape in which a plurality of cylindrical surfaces are connected in a wavy shape. Figure 2 The black arrow in [] is the flow direction of the refrigerant inside the water jacket 6.

[0052] The exhaust side spacer 11 is formed such that its height decreases toward the upstream side of the flow direction of the refrigerant inside the water jacket 6, that is, toward the inlet portion 9 ( Figure 1 from the upper right to the lower left in []). Thus, the refrigerant easily flows toward the cylinder head 3 side (upward) of the exhaust side spacer 11. It should be noted that the downstream side of the flow direction of the refrigerant inside the water jacket 6 of the exhaust side spacer 11 ( Figure 1 the upper right side in []) is approximately the same height as the suction side spacer 12, and is set lower than the depth of the water jacket 6.

[0053] The intake-side spacer 12 is formed in a shape that enters the interior of the inlet portion 9 from the water jacket 6. As Figures 3 to 5 shown, the intake-side spacer 12 is provided with a weir portion 13, ribs 14, a wall portion 15, and a platform portion 16.

[0054] The weir portion 13 is a planar portion located closer to the cylinder head 3 side than the first inlet 21. In the present embodiment, the weir portion 13 is provided between the first inlet 21 and the second inlet 22 inside the inlet portion 9. The weir portion 13 is disposed at a position that blocks the shortest path from the first inlet 21 to the second inlet 22. By providing the weir portion 13, the refrigerant flowing in from the first inlet 21 is suppressed from directly flowing out toward the cylinder head 3 side (upward), and the outflow from the second inlet 22 is suppressed.

[0055] The weir portion 13 of the present embodiment is provided at a position lower than the height of the intake-side spacer 12, and when viewed from above, its shape is formed along the shape of the inlet portion 9. The weir portion 13 is preferably in a shape that slopes toward the cylinder head 3 side (upward) as it goes downstream in the refrigerant flow direction, and more preferably in a shape of a smooth curved surface with a gradually steeper gradient. In Figure 3 the state shown, the refrigerant flowing in from the first inlet 21 through the weir portion 13 flows along the lower surface side of the weir portion 13, and is guided leftward and upward while slowly rotating in the left rotation direction shown by the black arrow, i.e., toward the exhaust side B of the cylinder block 2.

[0056] In this way, the weir portion 13 bends the flow of the refrigerant flowing from the first inlet 21 toward the radially inner side of the cylinder bore 4 into the inlet portion 9 in the circumferential direction of the cylinder bore 4, and also bends the flow of the refrigerant in the inlet portion 9 toward the second inlet 22 side (upper surface side) in the circumferential direction of the cylinder bore 4, and has the function of circulating in the water jacket 6 on the cylinder block 2 side. Part of the refrigerant guided in the left rotation direction flows closer to the cylinder head 3 side (upward) than the spacer 10 to circulate around the cylinder bore 4 and reach the second inlet 22 side (upper surface side) of the weir portion 13.

[0057] The rib 14 is a plate-like portion erected on the surface (upper surface side) on the second inlet 22 side in the weir portion 13, and rectifies the refrigerant closer to the second inlet 22 side than the weir portion 13. Here, the flow of the refrigerant circulating around the cylinder bore 4 is as Figure 3 shown by the hollow arrow. The rib 14 is in a shape that guides the flow of this refrigerant toward the second inlet 22. In the present embodiment, the rib 14 arranges two flat plates in parallel, and the refrigerant flows into the second inlet 22 through between the two flat plates. When viewed from above, the rib 14 is in a shape that linearly extends from the second inlet 22 toward the upstream side in the refrigerant flow direction.

[0058] When viewed from above, the rib 14 of the present embodiment extends parallel to the line connecting the boundary between the water jacket 6 and the inlet portion 9 and the second inlet 22. Further, when viewed from above, the second inlet 22 is disposed between the two ribs 14. It should be noted that the rib 14 does not circulate around the cylinder diameter 4 of the surface on the second inlet 22 side of the weir portion 13 from the gap between the weir portion 13, the water jacket 6, and the inlet portion 9 to rectify the flow of the inflowing refrigerant, and also has the effect of not disturbing the refrigerant flow near the second inlet 22.

[0059] The wall portion 15 is a plate-shaped portion erected on the surface (upper surface side) on the second inlet 22 side of the weir portion 13, which prevents the refrigerant closer to the second inlet 22 side than the weir portion 13 from flowing back to the first inlet 21 side. The wall portion 15 is disposed on the upstream side closer to the inlet portion 9 than the rib 14 (the upstream side edge in the refrigerant flow direction of the weir portion 13 in the present embodiment). As shown by the hollow arrow in Figure 3 , it has the function of guiding the refrigerant that attempts to flow back from the side closer to the second inlet 22 than the weir portion 13 through the gap between the weir portion 13 and the inlet portion 9 to the first inlet 21 side in the direction along the rib 14.

[0060] The platform portion 16 is a stepped portion formed in a shape that bulges upward from the weir portion 13 on the surface (upper surface side) on the second inlet 22 side of the weir portion 13. When viewed from above, the platform portion 16 protrudes from the inlet portion 9 to the water jacket 6 on the cylinder block 2 side on the downstream side in the refrigerant flow direction from the inlet portion 9. As shown in Figure 4 , the upper surface of the platform portion 16 is formed in a flat shape and is in surface contact with the lower surface of the gasket 8. In addition, the platform portion 16 has the function of preventing the refrigerant closer to the second inlet 22 side than the weir portion 13 from flowing out again in the direction along the circumferential surface of the cylinder diameter 4, and enabling the refrigerant in the water jacket 6 on the downstream side in the refrigerant flow direction flowing through the inlet portion 9 not to flow into the side closer to the second inlet 22 than the weir portion 13. By providing the platform portion 16, the refrigerant circulating around the cylinder diameter 4 easily flows into the second inlet 22. The refrigerant flowing into the interior of the water jacket 7 on the cylinder head 3 side through the second inlet 22 is discharged to the outside of the internal combustion engine 1 through an outlet (not shown).

[0061] [2. Function and Effect]

[0062] (1) In the cooling structure of the internal combustion engine 1 described above, the weir portion 13 of the spacer 10 is disposed above the first inlet 21. By providing the weir portion 13 above the first inlet 21, it is possible to suppress the refrigerant flowing in from the first inlet 21 from directly flowing toward the cylinder head 3 side, and make it easier for the refrigerant to circulate in the water jacket 6 on the cylinder block 2 side. In addition, by having the ribs 14 erected on the weir portion 13, it is possible to straighten the flow of the refrigerant in the vicinity of the weir portion 13. Therefore, the cooling efficiency of the refrigerant can be improved with a simple structure.

[0063] (2) In the above cooling structure, a second inlet 22 that connects the water jacket 6 on the cylinder block 2 side and the water jacket 7 on the cylinder head 3 side is provided, and the weir portion 13 is disposed between the first inlet 21 and the second inlet 22. By providing the weir portion 13, it is possible to make it difficult for the refrigerant flowing in from the first inlet 21 to directly flow out from the second inlet 22, and make it easier for the refrigerant to circulate in the water jacket 6 on the cylinder block 2 side. Therefore, the cooling efficiency of the refrigerant can be improved with a simple structure. In addition, since the ribs 14 are erected on the second inlet 22 side of the weir portion 13, it is possible to straighten the refrigerant on the upper surface (the surface on the second inlet 22 side) of the weir portion 13, and the refrigerant can effectively flow through the second inlet 22 to the water jacket 7 on the cylinder head 3 side. Therefore, the cooling efficiency of the refrigerant can be improved with a simple structure.

[0064] (3) The above second inlet 22 is located on the cylinder head 3 side (above) of the weir portion 13, and the weir portion 13 is formed in a shape that guides the refrigerant flowing in from the first inlet 21 in a direction along the circumferential surface of the cylinder bore 4. In addition, the refrigerant guided by the weir portion 13 circulates along the circumferential surface of the cylinder bore 4 and flows into the cylinder head 3 side of the weir portion 13. Thereby, it is easy to make the refrigerant circulate along the circumferential surface of the cylinder bore 4, and the cooling efficiency of the refrigerant can be further improved.

[0065] (4) In addition, the surface (upper surface) on the cylinder head 3 side of the weir portion 13 is formed to be inclined toward the cylinder head side as it goes downstream in the refrigerant flow direction. Thereby, it is possible to make the refrigerant circulating around the cylinder bore 4 flow effectively and smoothly toward the second inlet 22, and the cooling efficiency can be improved. It should be noted that on the surface of the weir portion 13, not only the surface (upper surface) on the cylinder head 3 side, but also the surface (lower surface) on the cylinder block 2 side can be formed in an inclined shape. In other words, the above weir portion 13 can be formed in an inclined curved surface shape with respect to the flow of the refrigerant flowing in from the first inlet 21. Thereby, for example, in the Figure 3 state shown, it is possible to guide the refrigerant flowing in from the first inlet 21 to the upper left while slowly rotating in the left rotation direction shown by the black arrow, and the cooling efficiency of the refrigerant can be further improved.

[0066] (5) The air intake side partition 12 is provided with a wall portion 15. The wall portion 15 is provided upright on the surface of the weir portion 13 on the side of the second inlet port 22 to prevent the refrigerant on the side of the second inlet port 22 from flowing back to the side of the first inlet port 21. By providing such a wall portion, the refrigerant circulating around the cylinder bore 4 can be easily flowed in the direction along the rib 14, and the refrigerant can be guided to the vicinity of the second inlet port 22. Therefore, the cooling efficiency of the refrigerant can be improved with a simple structure.

[0067] (6) Figure 3 As shown in FIG. 1 , when viewed from above, the rib 14 is shaped to extend linearly in the direction of flow of the refrigerant flowing along the surface (upper surface) of the weir portion 13 on the cylinder head 3 side. Figure 3 As shown, the rib 14 is shaped to extend linearly from the second introduction port 22 to the radially outer side of the second introduction port 22. Thus, the flow of the refrigerant near the second introduction port 22 can be stabilized, and the cooling efficiency of the refrigerant can be improved with a simple structure.

[0068] (7) In the above embodiment, when viewed from above, the plurality of ribs 14 are arranged in parallel at intervals. In addition, the second inlet port 22 is formed on the gasket 8 sandwiched between the cylinder body 2 and the cylinder head 3, and is arranged between the plurality of ribs 14 when viewed from above. In this way, by arranging the plurality of ribs 14 in parallel, the flow of the refrigerant can be prevented from being disturbed, thereby improving the fluidity of the refrigerant. In addition, by arranging the second inlet port 22 between the plurality of ribs 14, the refrigerant can be easily flowed to the cylinder head 3 side, which can further improve the cooling efficiency.

[0069] [3. Modifications]

[0070] The above embodiment is only an example and is not intended to exclude the application of various modifications and technologies that are not explicitly described in this embodiment. Various modifications may be made to the various components of this embodiment without departing from the scope of the present invention. In addition, selections or appropriate combinations may be made as needed. For example, in the above embodiment, an internal combustion engine 1 in which the inlet portion 9 is provided on the intake side A of the cylinder block 2 is exemplified, but the position of the inlet portion 9 is not limited thereto. In an internal combustion engine 1 in which the inlet portion 9 is provided on the exhaust side B, by providing a weir portion 13 or a rib 14 on the exhaust side spacer 11, the same functions and effects as those in the above embodiment can be achieved.

[0071] This application is based on Japanese patent application No. 2020-146595 filed on September 1, 2020, the contents of which are incorporated herein by reference.

Claims

1. A cooling structure for an internal combustion engine, characterized in that, Comprising: A water jacket that surrounds the cylinder bore of an internal combustion engine and is formed inside the cylinder block and the cylinder head; A spacer disposed inside the water jacket on the cylinder block side; An inlet portion that enlarges the water jacket in the expanding direction of the cylinder bore in the water jacket on the cylinder block side, and A first inlet port provided on the cylinder block side for introducing a refrigerant into the inlet portion, wherein the spacer has a weir portion that enters the inside of the inlet portion and is located closer to the cylinder head side than the first inlet port, and a plurality of ribs erected on the weir portion and extending along the refrigerant flow direction, The plurality of ribs are arranged in parallel.

2. The cooling structure of an internal combustion engine according to claim 1, characterized in that It comprises a second inlet port that connects the water jacket on the cylinder block side and the water jacket on the cylinder head side, The weir portion is disposed between the first inlet port and the second inlet port to prevent the refrigerant flowing in from the first inlet port from directly flowing out from the second inlet port, The ribs are erected on the surface of the weir portion on the second inlet port side to rectify the refrigerant on the second inlet port side.

3. The cooling structure of an internal combustion engine according to claim 2, characterized in that The second inlet port is located on the cylinder head side of the weir portion, The weir portion guides the refrigerant flowing in from the first inlet port in the direction of the circumferential surface along the cylinder bore, The guided refrigerant circulates on the circumferential surface of the cylinder bore and flows into the cylinder head side of the weir portion.

4. The cooling structure of an internal combustion engine according to claim 3, characterized in that The surface of the weir portion on the cylinder head side is formed to be inclined toward the cylinder head side as it goes downstream in the refrigerant flow direction.

5. The cooling structure of an internal combustion engine according to any one of claims 2 to 4, characterized in that The spacer has a wall portion erected on the surface of the weir portion on the second inlet port side to prevent the refrigerant on the second inlet port side from flowing back to the first inlet port side, The wall portion is located upstream of the ribs in the refrigerant flow direction.

6. The cooling structure of an internal combustion engine according to any one of claims 2 to 4, characterized in that When viewed from the cylinder head side, the ribs are formed in a shape that linearly extends along the flow direction of the refrigerant flowing on the cylinder head side of the weir portion.

7. The cooling structure of an internal combustion engine according to any one of claims 2 to 4, characterized in that The second inlet port is formed on a gasket sandwiched between the cylinder block and the cylinder head and is disposed between the plurality of ribs when viewed from above.

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