Spacer

Abstract

To provide a spacer which reduces unevenness in cooling performance due to the influence of dimensional unevenness of a cooling water flow passage.SOLUTION: A spacer 10 is arranged in a cooling water flow passage 3 provided in a state of surrounding a plurality of cylinder bores 2 in a cylinder block 1 of an internal combustion engine A, and restricts the flow of cooling water. The spacer includes: a body part 11 formed so as to be along the shape of the cooling water flow passage of the plurality of cylinder bores adjacent to each other; a lateral rib 12 protruding toward the cylinder bore side in the body part, formed along the flow direction of the cooling water flow passage, and for partitioning the cooling water flow passage vertically; a protrusion part 13 provided above the lateral rib, and coming into contact with a cylinder bore side wall 3c of the cooling water flow passage; and pressing means 15 for pressing the body part to the cylinder bore side, and bringing the lateral rib into contact with the cylinder bore side wall. The pressing means is provided on an opposite-to-cylinder bore surface 11b which is a surface on the opposite side from an opposing surface 11a with the cylinder bore in the body part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a spacer that is disposed in a cooling water flow path provided so as to surround a plurality of cylinder bores in a cylinder block of an internal combustion engine and regulates the flow of cooling water.

Background Art

[0002] In a cooling water flow path provided so as to surround a plurality of cylinder bores in a cylinder block of an internal combustion engine, a spacer for regulating the flow rate, flow velocity, etc. of the flowing cooling water is inserted and disposed from an opening at the upper part of the cooling water flow path. In Patent Documents 1 and 2 below, while suppressing overcooling of the cylinder bores by the cooling water by the spacer disposed in the cooling water flow path, cooling water is guided to the upper part of the portion (between the cylinder bores) between adjacent cylinder bores that tend to become hot.

[0003] Patent Document 1 discloses a stopper piece and a guide rib for guiding cooling water to a communication port provided to penetrate in the thickness direction, and a spacer provided on the surface opposite to the cylinder bore. In Patent Document 1, the communication port of the spacer communicates with a cooling water passage provided between the cylinder bores, and the cooling water is guided to the cooling water passage by the spacer, so that the space between the cylinder bores can be cooled.

[0004] Further, Patent Document 2 discloses a spacer having a cooling water passage port penetrating in the thickness direction of the spacer, and a guide wall and an inclined wall provided on the surface of the spacer opposite to the cylinder bore so that cooling water flows into the cooling water passage port. In Patent Document 2, the cooling water flowing in from the cooling water passage port can cool the upper parts of the space between the cylinder bores and the cylinder bore walls in the vicinity thereof.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] Incidentally, the cooling water channels formed in the cylinder block tend to have greater dimensional variations compared to spacers due to machining precision, and individual differences in channel width are likely to occur. Therefore, if the channel width in the upper part of the cooling water channel between the cylinder bores increases, the cooling water velocity decreases, and the cooling performance in the upper part between the cylinder bores decreases. Conversely, if the channel width in the upper part of the cooling water channel between the cylinder bores decreases, the cooling water velocity increases, and the cooling performance in the upper part between the cylinder bores increases. In this way, variations in the dimensional variations of the cooling water channels in the cylinder block result in variations in the cooling performance between the cylinder bores from one cylinder block to another.

[0007] This invention has been made in view of the above circumstances, and aims to provide a spacer that reduces variations in cooling performance caused by variations in the dimensions of the cooling water flow path. [Means for solving the problem]

[0008] To achieve the above objective, the spacer of the present invention is a spacer that is placed in a cooling water passage provided in the cylinder block of an internal combustion engine so as to surround a plurality of cylinder bores and restricts the flow of cooling water, comprising: a main body portion formed to conform to the shape of the cooling water passage of a plurality of adjacent cylinder bores; transverse ribs protruding toward the cylinder bore side from the main body portion and formed along the flow direction of the cooling water passage to divide the cooling water passage vertically; a convex portion provided above the transverse rib and in contact with the cylinder bore side wall of the cooling water passage; and a pressing means that presses the main body portion toward the cylinder bore side to bring the transverse rib and the cylinder bore side wall into contact, wherein the pressing means is provided on the anti-cylinder bore surface of the main body portion, which is the surface opposite to the surface facing the cylinder bore. Furthermore, it is provided at a position that overlaps with the protrusion in the thickness direction of the main body. It is characterized by the following:

[0009] Furthermore, in order to achieve the above objective, another spacer of the present invention is a spacer that is placed in a cooling water passage provided in a cylinder block of an internal combustion engine so as to surround a plurality of cylinder bores and restricts the flow of cooling water, comprising: a main body portion formed to conform to the shape of the cooling water passage of a plurality of adjacent cylinder bores; transverse ribs protruding toward the cylinder bore side from the main body portion and formed along the flow direction of the cooling water passage to divide the cooling water passage vertically; a convex portion provided above the transverse rib and in contact with the cylinder bore side wall of the cooling water passage; and a pressing means that presses the main body portion toward the cylinder bore side to bring the transverse rib and the cylinder bore side wall into contact, wherein the pressing means is provided on the anti-cylinder bore surface of the main body portion, which is the surface opposite to the surface facing the cylinder bore. The aforementioned protrusions are provided between the plurality of cylinder bores. It is characterized by being present.

[0010] Furthermore, the spacer may have vertical ribs that approach or contact the side wall of the cylinder bore of the cooling water passage when the pressing means presses the main body toward the cylinder bore, and these vertical ribs may be provided below the horizontal ribs on the main body.

[0011] Furthermore, in the above-described spacer, the longitudinal ribs may be provided in the cooling water passages between the plurality of cylinder bores, and the pressing means may be provided on the surface opposite the cylinder bore and at a position overlapping with the longitudinal ribs in the thickness direction of the main body.

[0012] Furthermore, in the above-mentioned spacer, the pressing means may be provided on the surface opposite the cylinder bore and at a position that overlaps with the protrusion in the thickness direction of the main body.

[0013] Furthermore, in the above-mentioned spacer, the protrusion may guide the cooling water into a flow hole provided between the plurality of cylinder bores in the flow direction of the cooling water passage.

[0014] Furthermore, in the above-mentioned spacer, the pressing means is made of a porous material that has the characteristic of expanding in the thickness direction from a compressed state when a predetermined external factor is applied, and may be in a compressed state before being placed in the cooling water channel. [Effects of the Invention]

[0015] Since the spacer of the present invention has the above-described configuration, it is possible to reduce variations in cooling performance due to variations in the dimensions of the cooling water flow path. [Brief explanation of the drawing]

[0016] [Figure 1]It is a schematic cross-sectional plan view schematically showing a state where a spacer according to the first embodiment is arranged in a cooling water flow path of an internal combustion engine. [Figure 2] It is a schematic perspective view schematically showing a part of the spacer, where (a) is a view explaining the side facing the cylinder bore and (b) is a view explaining the side opposite to the cylinder bore. [Figure 3] (a) is a schematic perspective view schematically showing a part of a state where the spacer is arranged in the cooling water flow path, and (b) and (c) are views schematically showing longitudinal sectional views in the arrow view along the X-X' line in FIG. 1, where (b) shows a state where the pressing means is compressed and (c) shows a state where the pressing means is restored. [Figure 4] (a) to (f) are schematic side views schematically showing a part of a modified example of the spacer in the first embodiment. [Figure 5] (a) to (f) are schematic side views schematically showing a part of a modified example of the spacer in the first embodiment. [Figure 6] (a) is a schematic perspective view schematically showing a part of a spacer according to the second embodiment, and (b) is a schematic side view of (a). [Figure 7] (a) is a schematic perspective view schematically showing a part of a state where the spacer is arranged in the cooling water flow path, and (b) and (c) are views schematically showing longitudinal sectional views corresponding to FIGS. 3(b) and (c), where (b) shows a state where the pressing means is compressed and (c) shows a state where the pressing means is restored. [Figure 8] (a) to (c) are schematic side views schematically showing a part of a modified example of the spacer in the second embodiment.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, the spacer 10 according to the present embodiment will be described with reference to the drawings. The spacer 10 according to this embodiment is disposed in a cooling water flow path 3 provided so as to surround a plurality of cylinder bores 2 in a cylinder block 1 of an internal combustion engine A, and regulates the flow of cooling water. The spacer 10 includes a main body portion 11, a horizontal rib 12, a convex portion 13, and a pressing means 15. The main body portion 11 is formed along the shape of the cooling water flow path 3 of adjacent plurality of cylinder bores 2. The horizontal rib 12 protrudes toward the cylinder bore 2 side in the main body portion 11, is formed along the flow direction of the cooling water flow path 3, and divides the cooling water flow path 3 vertically. The convex portion 13 is provided above the horizontal rib 12 and contacts the cylinder bore side wall 3c of the cooling water flow path 3. The pressing means 15 presses the main body portion 11 toward the cylinder bore 2 side to bring the horizontal rib 12 into contact with the cylinder bore side wall 3c. The pressing means 15 is provided on a surface 11b opposite to the surface 11a facing the cylinder bore 2 in the main body portion 11, which is the anti-cylinder bore surface. The following will be described in detail. Note that in some of the figures, some of the detailed reference numerals attached to other figures are omitted. Also, in this specification, based on the state where the spacer 10 is disposed in the cooling water flow path 3, the flow direction (longitudinal direction) and the depth direction (vertical direction) of each member are defined. Further, in the depth direction of the cooling water flow path 3, the opening 3e side is described as the upper side and the opposite direction as the lower side. Also, the flow direction of each member of the spacer 10 is described such that when disposed in the cooling water flow path 3, the direction approaching the cooling water discharge port 3g that is pipe-connected to a radiator (not shown) is the downstream side, and the opposite direction is the upstream side. Also, on the paper surfaces of FIGS. 4, 5, and 8, the right side is described as the downstream side in the flow direction and the left side as the upstream side in the flow direction.

[0018] <First Embodiment> The spacer 10 according to the first embodiment will be described with reference to FIGS. 1 to 3. As shown in Figure 1, the spacer 10 is positioned within the cooling water passage (water jacket) 3 of the cylinder block 1. The cylinder head 31 is positioned on the upper surface of the cylinder block 1, and the oil pan (not shown) is positioned on the lower surface of the cylinder block 1. The cylinder head 31 is integrally fastened to the cylinder block 1 such that the opening 3e of the cooling water passage 3 is closed. The cylinder block 1 constitutes an internal combustion engine A having multiple cylinders, and multiple cylinder bores (cylinders) 2 are arranged in series adjacent to each other. Multiple bolt insertion holes 1a are provided at appropriate locations on the cylinder block 1 for fastening the cylinder head 31 to the head gasket 30. A series of open-deck type groove-shaped cooling water passages 3 are formed around the multiple cylinder bores 2. Cooling water inlets 3f and cooling water outlets 3g leading to these cooling water passages 3 are also provided at appropriate locations on the cylinder block 1. The coolant outlet 3g is connected by piping to a radiator (not shown), and the outlet side of the radiator is connected by piping to the coolant inlet 3f via a water pump (not shown). This configures the system to circulate coolant (including antifreeze) between the coolant passage 3 and the radiator.

[0019] A cylinder bore wall 20 is formed between the cylinder bore 2 and the cooling water passage 3. The two wall surfaces facing each other across the cooling water passage 3 are composed of a cylinder bore side wall 3c on the cylinder bore 2 side and an anti-cylinder bore side wall 3d on the opposite side of the cylinder bore 2. The cooling water passage 3 is formed to efficiently cool the cylinder bore wall 20. The cooling water passage 3 has a plurality of arc-shaped portions 3a formed to surround the cylinder bore 2 via the cylinder bore wall 20, and a plurality of constricted portions 3b formed to be close to each other and in pairs between adjacent cylinder bores 2,2. The groove width of the constricted portions 3b is formed to be larger than the groove width of the other arc-shaped portions 3a of the cooling water passage 3. Flow holes 20a are provided in the cylinder bore wall 20 between the plurality of cylinder bores 2 in the flow direction of the cooling water passage 3. The flow hole 20a opens from the cylinder bore side wall 3c adjacent to the constricted portion 3b of the cooling water passage 3 and extends diagonally upward toward the space between the cylinder bores 2, 2 (see Figures 1, 3(b) and 3(c)). This allows the flow hole 20a to circulate the cooling water flowing through the cooling water passage 3 between the adjacent cylinder bores 2, 2. The flow hole 20a communicates with a flow hole in the cylinder head 31 (not shown).

[0020] <Spacer> As shown in Figure 1, the spacer 10 is a half-shaped spacer formed to be installed in approximately half of the left side of the cooling water channel 3 on the plane of Figure 1. The spacer 10 comprises a main body 11 made of resin material and a pressing means 15 made of a porous material fixed to the main body 11. The spacer 10 is inserted through the opening 3e of the cooling water channel 3 and assembled into the cooling water channel 3 to restrict the flow of cooling water.

[0021] The main body 11 is made of a resin material, and is made of various synthetic resins such as thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyethylene, polypropylene, ABS, acrylic, polycarbonate, polyamide, polyacetal, polyphenylene sulfide, and polyether ether ketone. Examples of thermosetting resins include phenolic resins, epoxy resins, and polyurethane resins. The resin material may also have various additives added to it, or it may be a resin composite material containing reinforcing fibers such as carbon fiber or glass fiber.

[0022] The main body 11 is a long plate formed in a curved shape to conform to the shape of the cooling water passages 3 of the adjacent cylinder bores 2. Specifically, the main body 11 has a plurality of arc portions 110 formed to surround the plurality of cylinder bores 2 via the cylinder bore walls 20, and connecting portions 111 formed between adjacent arc portions 110 to connect the arc portions 110 to each other. In this embodiment, corresponding to a three-cylinder internal combustion engine A, the main body 11 has three arc portions 110 corresponding to the number of cylinders. The main body 11 also has integrally formed transverse ribs 12, two protrusions 13, and two longitudinal ribs 14.

[0023] On the surface 11a of the main body 11 facing the cylinder bore 2 (hereinafter referred to as "the surface 11a of the main body 11"), a plate-shaped transverse rib 12 is formed that protrudes toward the cylinder bore 2 and curves along the flow direction of the cooling water passage 3. The transverse rib 12 is formed from the upstream end to the downstream end in the flow direction of the main body 11. Furthermore, the end face 12c of the transverse rib 12 on the cylinder bore 2 side is shaped to conform to the shape of the cylinder bore side wall 3c of the cooling water passage 3. Therefore, when the main body 11 is pressed toward the cylinder bore by the pressing means 15, the end face 12c of the transverse rib 12 comes into contact with the cylinder bore side wall 3c of the cooling water passage 3. The transverse rib 12 is formed at an appropriate position in the vertical direction of the main body 11 so as to divide the cooling water passage 3 vertically when the spacer 10 is placed in the cooling water passage 3. In this embodiment, as shown in Figure 2(a), the transverse rib 12 is formed above the vertical center of the main body 11. Furthermore, as shown in Figures 3(a) to 3(c), the transverse rib 12 is formed so that when the spacer 10 is placed in the cooling water passage 3, it is below the opening 20aa of the flow hole 20a on the cooling water passage 3 side. The transverse rib 12 is formed so that when the pressing means 15 of the spacer 10 placed in the cooling water passage 3 is expanded, its width is greater than the width dimension between the anti-cylinder bore surface 11b and the anti-cylinder bore side wall 3d of the main body 11.

[0024] On the upper side of the transverse rib 12, a plate-shaped projection 13 is formed that protrudes toward the cylinder bore 2 and extends in the vertical direction. As shown in Figure 1, the projection 13 is provided between a plurality of cylinder bores 2, 2 and is formed to protrude from the surface 111a of the connecting portion 111 of the main body 11 that faces the cylinder bore 2 (hereinafter referred to as "the surface 111a of the connecting portion 111"). This projection 13 has a projection dimension that allows it to contact the cylinder bore side wall 3c of the cooling water passage 3 between the plurality of cylinder bores 2, 2 when the main body 11 is pressed toward the cylinder bore 2 by the pressing means 15. As shown in Figure 2(a), the projection 13 is formed to extend upward from the upper surface 12a of the transverse rib 12 to a dimension that does not reach the upper end portion 11c of the main body 11. The protrusion 13 is positioned close to the flow hole 20a when the spacer 10 is placed in the cooling water passage 3, and is located downstream of the adjacent flow hole 20a in the flow direction of the cooling water passage 3. As a result, the cooling water tends to accumulate around the protrusion 13, and the protrusion 13 can guide the accumulated cooling water to the flow hole 20a provided between the multiple cylinder bores 2.

[0025] Below the transverse rib 12, a plate-shaped vertical rib 14 is formed on the opposing surface 111a of the connection portion 111 in the main body portion 11, projecting toward the cylinder bore 2 and extending vertically. As shown in Figure 2(a), the vertical rib 14 is formed with dimensions that extend downward from the lower surface 12b of the transverse rib 12 to the lower end portion 11d of the main body portion 11. Furthermore, the vertical rib 14 is provided approximately at the center of the flow direction of the opposing surface 111a of the connection portion 111, and is positioned upstream of the protrusion 13 in the flow direction of the cooling water passage 3. Therefore, the protrusion 13 and the vertical rib 14 are configured not to overlap in the vertical direction. The vertical rib 14 is formed to project toward the cylinder bore 2 from the opposing surface 111a so as to contact the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 presses the main body portion 11 toward the cylinder bore 2.

[0026] A pressing means 15 made of a porous material, as described later, is provided on the anti-cylinder bore surface 11b, which is the surface opposite to the opposing surface 11a of the main body 11. More specifically, the center of the pressing means 15 in the flow direction is provided on the anti-cylinder bore surface 111b, which is the surface opposite to the opposing surface 111a of the connecting portion 111, which is part of the main body 11. The ends of the pressing means 15 in the flow direction are provided so as to reach a part of the anti-cylinder bore surface 110b, which is the surface opposite to the opposing surface 110a of the arc portion 110 with respect to the cylinder bore 2 (hereinafter referred to as "opposing surface 110a of the arc portion 110"). The pressing means 15 is provided on the anti-cylinder bore surface 111b of the connecting portion 111 at a position that overlaps with the convex portion 13 in the thickness direction of the main body 11. Furthermore, in this embodiment, as shown in Figures 2(b) and 3(b)(c), the pressing means 15 is formed with a vertical dimension that overlaps with the upper part of the vertical rib 14 and the thickness direction of the main body 11, from the upper end 11c of the main body 11. When the pressing means 15 is enlarged, the spacer 10 restricts the flow of cooling water between the anti-cylinder bore surface 11b of the main body 11 and the anti-cylinder bore side wall 3d of the cooling water passage 3, and concentrates the cooling water on the opposing surface 11a side of the main body 11.

[0027] The pressing means 15 is made of a porous material that expands in the thickness direction from a compressed state when a predetermined external factor is applied, and in this embodiment, a cellulose sponge is used. The cellulose sponge is made of natural materials consisting of cellulose derived from pulp and natural fibers (e.g., cotton) added as reinforcing fibers, and has an open-cell structure and excellent water absorption. Here, cellulose has hydrophilic groups (OH) and is known to be chemically compatible with moisture. Therefore, when the cellulose sponge is dried under pressure, hydrogen bonds form between cellulose molecules and it is maintained in a compressed state, while when exposed to moisture from this state, water molecules break the hydrogen bonds between cellulose molecules and it recovers from the compressed state. For this reason, the cellulose sponge is suitable as the pressing means 15. The pressing means 15 is in a compressed state before being placed in the cooling water channel 3. Figure 3(b) shows the pressed means 15 in its compressed state immediately after being placed in the cooling water channel 3 and before contact with the cooling water, while Figures 1 and 3(c) show the pressed means 15 in its expanded state after contact with the cooling water.

[0028] As described above, when the spacer 10 is placed in the cooling water passage 3, the pressing means 15 is in a thin, compressed state before expansion. Therefore, contact with the side walls of the cooling water passage 3 (cylinder bore side wall 3c, anti-cylinder bore side wall 3d) is suppressed, making it easier to smoothly place the spacer 10 in the cooling water passage 3. When cooling water is supplied to the cooling water passage 3, the pressing means 15 comes into contact with the cooling water, absorbs water, expands, and increases in thickness. Then, as shown in Figures 1 and 3(c), the expanded pressing means 15 presses the main body 11 towards the cylinder bore 2, causing the transverse ribs 12, protrusions 13, and longitudinal ribs 14 to contact the cylinder bore side wall 3c of the cooling water passage 3. As a result, the spacer 10 can control and regulate the flow of cooling water.

[0029] In this embodiment, the spacer 10 is provided with a transverse rib 12 that protrudes toward the cylinder bore 2 side from the main body 11. When cooling water flows through the cooling water passage 3, the main body 11 is pressed toward the cylinder bore 2 side by the pressing means 15, and the end face 12c of the transverse rib 12 toward the cylinder bore 2 side comes into contact with the cylinder bore side wall 3c of the cooling water passage 3. As a result, the dimension between the main body 11 and the cylinder bore side wall 3c of the cooling water passage 3, that is, the width dimension of the transverse rib 12, becomes the effective width of the passage through which the cooling water flows.

[0030] The dimensional variation of the spacer 10 during manufacturing tends to be smaller than the dimensional variation of the cooling water passage 3 formed in the cylinder bore 2 during machining. In this embodiment, the width dimension of the transverse rib 12 becomes the effective width of the passage through which the cooling water flows. Therefore, even if there is variation in the width of the cooling water passage 3 due to individual differences in the cylinder bore 2, the dimensional variation during machining of the transverse rib 12, which has the effective passage width, is small, thus reducing the variation in cooling performance due to the dimensional variation of the cooling water passage 3.

[0031] In the spacer 10 of this embodiment, the flow of cooling water is restricted by the enlarged pressing means 15 on the side of the main body 11 opposite the cylinder bore surface 11b. Furthermore, when the pressing means 15 is enlarged, the width of the flow path between the side of the main body 11 opposite the cylinder bore surface 11b and the side wall 3d of the cooling water flow path 3 opposite the cylinder bore is smaller than the width of the flow path (width of the transverse rib 12) between the opposing surface 11a of the main body 11 and the side wall 3c of the cylinder bore of the cooling water flow path 3. As a result, the flow of cooling water is concentrated in the flow path between the opposing surface 11a of the main body 11 and the side wall 3c of the cylinder bore of the cooling water flow path 3, that is, on the side of the transverse rib 12.

[0032] Furthermore, the spacer 10 of this embodiment can divide the cooling water passage 3 vertically by a transverse rib 12 formed along the flow direction of the cooling water passage 3, thereby dividing the cooling water passage 3 vertically. A protrusion 13 is provided on the upper side of the transverse rib 12, and a vertical rib 14 is provided on the lower side. The vertical rib 14 has a vertical dimension from the lower surface 12b of the transverse rib 12 to the lower end 11d of the main body 11, and is shaped to contact the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 is restored (see Figure 3(c)). Therefore, the flow of cooling water is restricted by the vertical rib 14 on the lower side of the transverse rib 12, so the flow of cooling water can be concentrated on the upper side of the transverse rib 12, making it easier to cool the upper part of the cylinder bore 2, which tends to get hot.

[0033] In this way, the spacer 10 of this embodiment first divides the cooling water flow path 3 into a cylinder bore side (right side of the main body 11 in the plane of Figure 1) and an anti-cylinder bore side (left side of the main body 11 in the plane of Figure 1) by the main body 11. On the divided anti-cylinder bore side, the flow of cooling water is restricted by the enlarged pressing means 15 and the smaller flow path width compared to the cylinder bore side, causing the cooling water flow to concentrate on the cylinder bore side of the main body 11. On the cylinder bore side of the main body 11, the flow of cooling water is divided vertically by the transverse rib 12. Below the transverse rib 12, the flow of cooling water is restricted by the vertical rib 14, causing the cooling water flow to concentrate on the upper side of the transverse rib 12. In this way, in this embodiment, the flow of cooling water tends to concentrate in the area surrounded by the upper surface 12a of the transverse rib 12, the opposing surface 11a of the main body 11 above the upper surface 12a of the transverse rib 12, and the cylinder bore side wall 3c of the cooling water flow path 3. Therefore, the upper part of cylinder bore 2, which tends to get very hot, is more easily cooled.

[0034] Furthermore, the pressing means 15 is positioned so as to overlap with a portion of the upper side of the vertical rib 14 in the thickness direction of the main body 11. This makes it easier for the vertical rib 14 to come into contact with the cylinder bore side wall 3c of the cooling water passage 3 between the multiple cylinder bores 2 when the pressing means 15 presses the main body 11. Because the vertical rib 14 comes into contact with the cylinder bore side wall 3c of the cooling water passage 3, the water flow in the cooling water passage 3 between the multiple cylinder bores 2 is concentrated in the upper part between the cylinder bores 2,2, thereby increasing the cooling effect in the upper part between the bores and thus enhancing the knock prevention effect.

[0035] Furthermore, the protrusion 13 is formed to contact the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 is enlarged. Therefore, even when the main body 11 is pressed toward the cylinder bore 2 by the pressing means 15, the protrusion 13 contacts the cylinder bore side wall 3c, which suppresses deformation of the main body 11 by the pressing means 15 and maintains cooling performance. In addition, since the pressing means 15 is positioned to overlap with the protrusion 13 in the thickness direction of the main body 11, when the pressing means 15 presses the main body 11, the protrusion 13 is more likely to contact the cylinder bore side wall 3c of the cooling water passage 3 between the multiple cylinder bores 2 more reliably. Furthermore, as described above, the protrusion 13 can retain cooling water and guide it into the flow holes 20a provided between the multiple cylinder bores 2, so that the space between the cylinder bores 2, 2 can be cooled more efficiently. Furthermore, as shown in Figure 3(c), a gap is formed between the upper end of the protrusion 13 and the head gasket 30, so that even if coolant is retained by the protrusion 13, coolant can still flow above the protrusion 13. In addition, in this embodiment, the protrusion 13 and vertical rib 14, which are provided substantially perpendicular to the plate-shaped horizontal rib 12, make the horizontal rib 12 less prone to deformation.

[0036] <Modified form of the first embodiment> Next, modifications of the first embodiment will be described with reference to Figures 4(a) to 4(f). Figure 4 is a schematic side view illustrating modifications of the transverse rib 12, protrusion 13, and longitudinal rib 14. It does not show the entire main body 11, but rather the main parts are shown centered on one connection part 111 of the main body 11. Also, in Figure 4, the circle drawn with a dashed line indicates the opening 20aa on the cooling water flow path side of the flow hole 20a provided between the cylinder bores 2, 2. In the description of each modification, the explanation of the configuration and effects of parts common to the first embodiment shown in Figures 1 to 3 will be omitted. Note that in each modification shown in Figure 4, the pressing means 15 has substantially the same configuration as that of the first embodiment, and therefore its explanation will be omitted.

[0037] In Figure 4(a), the transverse rib 12 is formed with substantially the same configuration as in the first embodiment, but the protrusion 13 is a plate extending along the longitudinal direction of the main body 11, projecting from the upper end portion 11c of the main body 11 toward the cylinder bore 2 side. This protrusion 13 is formed around the connecting portion 111 of the main body 11 and is formed along the longitudinal direction of the main body 11 with a size that allows it to contact the cylinder bore side wall 3c in the portion adjacent to the constricted shape portion 3b. Both ends of this protrusion 13 in the flow direction are formed to reach the opposing surface 110a of the arc portion 110. In this modified example, the longitudinal rib 14 is not provided below the transverse rib 12. Therefore, in this modified example, the effect of concentrating the flow of cooling water on the upper side of the transverse rib 12 is small, and since the protrusion 13 is provided along the flow direction, the effect of guiding the flow of cooling water into the flow hole 20a is small. This protrusion 13 contacts the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 is expanded, and has the effect of suppressing deformation of the main body 11. Therefore, although the improvement in cooling performance on the upper side of the transverse rib 12 is small, it has the effect of reducing variations in cooling performance by reducing dimensional variations in the cooling water passage 3 during processing and suppressing deformation of the main body 11.

[0038] The protrusion 13 in Figure 4(b) has substantially the same configuration as the protrusion 13 in Figure 4(a). On the other hand, the transverse rib 12 is not formed at both ends in the longitudinal direction of the main body 11, but extends longitudinally from the connecting portion 111, and its longitudinal dimension is substantially the same as or slightly larger than the longitudinal dimension of the protrusion 13. Below the transverse rib 12, a vertical rib 14 is provided, which has substantially the same configuration as in the first embodiment. As a result, the flow of cooling water is restricted by the vertical rib 14, and the flow of cooling water is concentrated locally between the protrusion 13 and the transverse rib 12. As a result, even though the protrusion 13 is provided along the flow direction, the cooperation of the transverse rib 12 and the vertical rib 14 makes it easier to guide the cooling water into the flow hole 20a.

[0039] In Figure 4(c), the transverse rib 12 and the longitudinal rib 14 are formed with substantially the same configuration as in the first embodiment. The protrusion 13 includes a plate-shaped guide portion 131 and an upper plate portion 132. The guide portion 131 extends from its lower end 131a, which overlaps vertically with the longitudinal rib 14 on the upper surface 12a of the transverse rib 12, upward and inclined downstream in the flow direction of the cooling water channel 3 to the upper end 11c of the main body portion 11. The upper plate portion 132 extends from the upper end of the guide portion 131 upstream in the flow direction of the cooling water channel 3. In this modified example, the flow of cooling water below the transverse rib 12 is restricted by the longitudinal rib 14, and the flow of cooling water concentrates above the transverse rib 12. The cooling water flowing above the transverse rib 12 tends to accumulate in the space enclosed by the transverse rib 12, the guide portion 131, and the upper plate portion 132, and is easily guided into the flow hole 20a.

[0040] In Figure 4(d), the transverse ribs 12 and longitudinal ribs 14 have substantially the same configuration as in the first embodiment. On the other hand, the protrusion 13 is positioned slightly downstream in the flow direction of the cooling water passage 3 compared to the first embodiment, and is formed on the upstream side of the opposing surface 110a of the arc portion 110 located downstream of the connection portion 111. Furthermore, the protrusion 13 has a larger vertical dimension than that of the first embodiment, and is configured to extend from the upper surface 12a of the transverse rib 12 to the upper end portion 11c of the main body portion 11. When the pressing means 15 is greatly enlarged, this protrusion 13 contacts the cylinder bore side wall 3c located a little distance from between the cylinder bores 2, 2, but because it is configured to extend from the upper surface 12a of the transverse rib 12 to the upper end portion 11c of the main body portion 11, it has a greater effect of stopping and accumulating the flow of cooling water than in the first embodiment. Therefore, even if the spacer 10 in Figure 4(d) is configured such that the protrusion 13 is in contact with the cylinder bore side wall 3c at a position slightly away from the space between the cylinder bores 2, 2, the cooling water is retained and guided into the flow hole 20a, thereby providing a cooling effect on the space between the cylinder bores 2, 2.

[0041] In Figure 4(e), the transverse rib 12 and the longitudinal rib 14 have substantially the same configuration as in the first embodiment. On the other hand, the protrusion 13 has a shape that combines the protrusion 13 in Figure 4(a) and the protrusion 13 in Figure 4(d). The protrusion 13 comprises a longitudinal rib portion 133 extending from the upper surface 12a of the transverse rib 12 to the upper end portion 11c of the main body portion 11, and an upper plate portion 132 formed extending from the upper end portion of the longitudinal rib portion 133 toward the upstream side in the flow direction of the cooling water passage 3. Cooling water flowing above the transverse rib 12 tends to accumulate in the space enclosed by the transverse rib 12, the longitudinal rib portion 133, and the upper plate portion 132, and is more easily guided into the flow hole 20a.

[0042] In Figure 4(f), the transverse rib 12 and the longitudinal rib 14 have substantially the same configuration as in the first embodiment. On the other hand, the protrusion 13 is a plate that extends along the flow direction of the main body 11, similar to Figures 4(a) and (b). The position of this protrusion 13 in the vertical direction is different from that in Figures 4(a) and (b), and it is positioned approximately in the center between the upper end portion 11c of the main body 11 and the transverse rib 12. Furthermore, the protrusion 13 is provided such that the opening 20aa of the flow hole 20a is located approximately in the center in the vertical direction between the protrusion 13 and the transverse rib 12. In this modified example, the protrusion 13 has little effect on retaining cooling water, but when cooling water flowing above the transverse rib 12 flows between the protrusion 13 and the transverse rib 12, it is more easily guided into the flow hole 20a.

[0043] <Modified form of the pressing means 15> Next, we will explain modified shapes and positions of the pressing means 15 with reference to Figures 5(a) to 5(f). Figures 5(a) to 5(e) use modified versions of the spacer 10 in Figure 4(a), and Figure 5(f) uses modified versions of the spacer 10 in Figure 4(d). In Figures 5(a) to 5(f), the pressing means 15 is shown by a dashed line.

[0044] The spacers 10 in Figures 5(a) to 5(e) have transverse ribs 12 and protrusions 13 with substantially the same configuration as the spacer 10 in Figure 4(a). In Figure 5(a), the pressing means 15 has a flow-direction dimension that overlaps with the entire protrusion 13 and the thickness direction of the main body 11, and has a flow dimension that is slightly larger than the flow-direction dimension of the protrusion 13. Both ends of the pressing means 15 in the flow direction reach the anti-cylinder bore surface 110b of a pair of arc portions 110 adjacent to both ends of the connecting portion 111 in the flow direction. The pressing means 15 also has a vertical dimension that extends from the upper end 11c of the main body 11 to the lower surface 12b of the transverse rib 12. As a result, the pressing means 15 can reliably press the protrusion 13 and the transverse rib 12 against the cylinder bore side wall 3c adjacent to the constricted portion 3b.

[0045] Figure 5(b) shows a pressing means 15A having substantially the same configuration as the pressing means 15 in Figure 5(a), and a separate pressing means 15B provided below and spaced apart from the pressing means 15A. The pressing means 15B provided below the pressing means 15A has substantially the same dimensions in the flow direction as the pressing means 15A, and dimensions in the vertical direction such that it does not reach the pressing means 15A from the lower end 11d of the main body 11. In this way, the spacer 10 may be provided with multiple pressing means so as to overlap the main body 11 in the vertical direction.

[0046] In Figure 5(c), the pressing means 15 has substantially the same dimensions in the flow direction as the pressing means 15 in Figure 5(a), and has vertical dimensions from the upper end 11c to the lower end 11d of the main body 11. Therefore, when the pressing means 15 is large, the flow of cooling water between the anti-cylinder bore surface 11b of the main body 11 and the anti-cylinder bore side wall 3d of the cooling water passage 3 is more restricted than in the first embodiment. As a result, the effect of concentrating the flow of cooling water on the side of the main body 11 facing the cylinder bore 2 (the side on which the transverse rib 12 is provided) becomes greater.

[0047] In Figure 5(d), the dimension of the pressing means 15 in the flow direction is smaller than the dimension of the protrusion 13 in the flow direction, and it overlaps with the connecting portion 111 and the main body portion 11 in the thickness direction, but does not overlap with the arc portion 110 in the thickness direction of the main body portion 11. Furthermore, the vertical dimension of the pressing means 15 is formed to extend from the upper end portion 11c of the main body portion 11 to a position approximately midway between the transverse rib 12 and the lower end portion 11d of the main body portion 11. Therefore, when the pressing means 15 is expanded, the effect of restricting the flow of cooling water between the anti-cylinder bore surface 11b of the main body portion 11 and the anti-cylinder bore side wall 3d of the cooling water passage 3 is greater than that of the first embodiment and smaller than that of the modified example in Figure 5(c).

[0048] In Figure 5(e), the dimension of the pressing means 15 in the flow direction is larger than the dimension of the protrusion 13 in the flow direction. Also, the vertical dimension of the pressing means 15 is formed to extend from the upper end 11c of the main body 11 to a position below the lower surface 12b of the transverse rib 12. Since the area of ​​overlap between the transverse rib 12 and the main body 11 in the thickness direction is larger in the pressing means 15 than in the first embodiment, contact between the transverse rib 12 and the cylinder bore side wall 3c of the cooling water passage 3 can be made more reliable when the pressing means 15 is expanded.

[0049] The spacer 10 in Figure 5(f) has a transverse rib 12, a protrusion 13, and a longitudinal rib 14, which are substantially the same configuration as the spacer 10 in Figure 4(d). In Figure 5(f), there is a pressing means 15A and a pressing means 15B which is separate from the pressing means 15A. The pressing means 15A is provided at a position and size that overlaps with the entire protrusion 13 in the thickness direction of the main body 11. The upstream end of the pressing means 15A in the flow direction reaches the anti-cylinder bore surface 111b of the connecting portion 111, and the downstream end of the pressing means 15A reaches the anti-cylinder bore surface 110b of the arc portion 110. The upper end of the pressing means 15B is arranged so as to be in contact with the lower end of the pressing means 15A, and the downstream end of the pressing means 15A and the downstream end of the pressing means 15B are arranged so as to overlap in the vertical direction. The pressing means 15B is positioned and sized to overlap with a portion of the transverse rib 12 and the entirety of the longitudinal rib 14 in the thickness direction of the main body 11. In other words, in this modified example, the pressing means 15A and 15B are provided from the upper end 11c to the lower end 11d of the main body 11. Therefore, when the pressing means 15A and 15B are expanded, the flow of cooling water between the anti-cylinder bore surface 11b of the main body 11 and the anti-cylinder bore side wall 3d of the cooling water passage 3 is more restricted. Furthermore, since the pressing means 15B is configured to overlap with the entirety of the longitudinal rib 14 in the thickness direction of the main body 11, contact between the longitudinal rib 14 and the cylinder bore side wall 3c of the cooling water passage 3 is made more certain, and the cooling water restriction effect by the longitudinal rib 14 can be made more certain. As a result, the water flow in the cooling water passage 3 between the multiple cylinder bores 2 is concentrated in the upper part between the cylinder bores 2, 2, so the cooling effect in the upper part between the bores is increased and the knock prevention effect is greatly enhanced. In Figure 5(f), the pressing means 15A and a separate pressing means 15B are shown, but the pressing means 15A and the pressing means 15B may be formed as a single unit.

[0050] <Second Embodiment> Next, the spacer 10A according to the second embodiment will be described with reference to Figures 6 and 7. Note that the configuration and effects of parts common to the spacer 10 of the first embodiment will be omitted. Also, in this embodiment, there is no flow hole 20a between the cylinder bores 2, 2. In this embodiment, the head gasket 30 positioned above the cylinder block 1 has a flow hole 30a that penetrates vertically, located at a position that overlaps vertically with the constricted portion 3b of the cooling water passage 3, which is located between adjacent cylinder bores 2, 2. The flow hole 30a of the head gasket 30 communicates with a flow hole (not shown) in the cylinder head 31.

[0051] In the second embodiment, the configuration of the main body 11 and the transverse rib 12 is substantially the same as that of the first embodiment. As shown in Figures 6(a) and 6(b), the protrusion 13 comprises a guide portion 131 and an upper plate portion 132. The guide portion 131 is provided spaced upward from the transverse rib 12, and the lower end portion 131a of the guide portion 131 is provided in a position that overlaps with the vertical rib 14 in the vertical direction. The guide portion 131 is formed to slope upward from the lower end portion 131a toward the downstream side in the flow direction of the cooling water channel 3.

[0052] The upper plate portion 132 is a plate that protrudes from the upper end portion 11c of the main body portion 11 toward the cylinder bore 2 and extends in the flow direction. The dimensions of the upper plate portion 132 in the flow direction are slightly larger than those of the connection portion 111 of the main body portion 11 in the flow direction. The upper plate portion 132 has a notch portion 132a formed by cutting through a part of the cylinder bore 2 side in the vertical direction and cutting out in the thickness direction of the main body portion 11. As shown in Figure 7(a), this notch portion 132a is formed in a position that overlaps vertically with the flow hole 30a of the head gasket 30 when the spacer 10A is placed in the cooling water flow path 3. In the convex portion 13, the guide portion 131 and the upper plate portion 132 are formed integrally, and the downstream end face 132aa of the notch portion 132a is formed to be substantially flush with the upstream face 131b of a part of the guide portion 131 toward the cylinder bore 2. As a result, the cooling water flowing from the upstream side of the cooling water passage 3 flows along the upstream surface 131b of the guide portion 131, passes through the notch 132a of the upper plate portion 132, and is easily guided into the flow hole 30a of the head gasket 30. In addition, since a gap is formed between the protrusion 13 and the transverse rib 12, the cooling water flowing on the upper side of the cooling water passage 3 is guided into the flow hole 30a of the head gasket 30, and the cooling water that is not guided flows to the downstream side of the cooling water passage 3.

[0053] Unlike the first embodiment, the vertical ribs 14 are formed to protrude from the surface 11a of the main body 11 facing the cylinder bore 2 toward the cylinder bore 2, so as to be close enough that they do not come into contact with the side wall 3c of the cooling water passage 3 when the pressing means 15 is expanded (see Figure 7(c)). In other words, in this embodiment, the projection dimension of the vertical ribs 14 toward the cylinder bore 2 is smaller than the projection dimension of the horizontal ribs 12 toward the cylinder bore 2 (see Figures 6(a), 7(b) and 7(c)). Since the vertical ribs 14 are configured to be close enough to the side wall 3c of the cylinder bore of the cooling water passage 3 without coming into contact with it, the pressing means 15 is provided so as to overlap with the convex portion 13 in the thickness direction of the main body 11 and a part of the horizontal rib 12, but not with the vertical ribs 14 (see Figure 6(b)).

[0054] In this embodiment, similar to the spacer 10 of the first embodiment, when the spacer 10A is placed in the cooling water passage 3, the pressing means 15 is in a thin, compressed state before expansion. Therefore, it is easier to smoothly place the spacer 10A in the cooling water passage 3 by suppressing contact with the side walls of the cooling water passage 3 (cylinder bore side wall 3c, anti-cylinder bore side wall 3d) (see Figure 7(b)). When cooling water is supplied to the cooling water passage 3, the pressing means 15 comes into contact with the cooling water, absorbs water, expands, and increases in thickness (see Figure 7(c)). Then, the expanded pressing means 15 presses the main body 11 toward the cylinder bore 2, causing the transverse rib 12 and protrusion 13 to contact the cylinder bore side wall 3c of the cooling water passage 3. Furthermore, since the vertical ribs 14 are positioned close enough not to contact the cylinder bore sidewall 3c, a small gap is formed between the vertical ribs 14 and the cylinder bore sidewall 3c. However, the cooling water flowing below the horizontal ribs 12 is restricted and its flow is stagnant. As a result, the spacer 10A concentrates the flow of cooling water into the cooling water passage 3 above the horizontal ribs 12 and guides a portion of the cooling water into the flow hole 30a of the head gasket 30, allowing the upper part of the cylinder bore 2 to be cooled efficiently. In addition, the lower part of the horizontal ribs 12 can be cooled to a moderate degree.

[0055] <Modified form of the second embodiment> Next, a modified example of the spacer 10A according to the second embodiment will be described with reference to Figures 8(a) to 8(c). Note that the explanation of the configuration and effects of parts common to the second embodiment will be omitted. In the modified examples shown in Figures 8(a) to 8(c), the configuration and effects of the transverse ribs 12 and longitudinal ribs 14 are substantially the same as those of the second embodiment.

[0056] In Figure 8(a), the protrusion 13 is formed on the opposing surface 110a of the arc portion 110 and extends from the upper surface 12a of the transverse rib 12 to the upper end portion 11c of the main body portion 11. The protrusion 13 is located downstream of the flow hole 30a of the head gasket 30 in the flow direction of the cooling water passage 3. As a result, the cooling water whose flow is restricted by the protrusion 13 is more easily guided to the flow hole 30a of the head gasket 30, which is located above the spacer 10A.

[0057] In Figure 8(b), the protrusion 13 is formed on the opposing surface 110a of the arc portion 110 and includes a vertical rib portion 133 extending from the upper surface 12a of the transverse rib 12 to the upper end portion 11c of the main body portion 11, as well as a first upper plate portion 132A and a second upper plate portion 132B. The first upper plate portion 132A is formed extending upstream in the flow direction of the cooling water passage 3 from the upper end portion of the vertical rib portion 133. The second upper plate portion 132B is located upstream of the first upper plate portion 132A in the flow direction and is provided at a distance from the first upper plate portion 132A in the flow direction. A gap 134 is formed between the first upper plate portion 132A and the second upper plate portion 132B, penetrating in the vertical direction. The gap 134 is formed so as to overlap in the vertical direction with the flow hole 30a of the head gasket 30 when the spacer 10A is placed in the cooling water passage 3. Cooling water flowing from upstream tends to accumulate and be regulated in the space surrounded by the vertical rib portion 133, the first upper plate portion 132A, the second upper plate portion 132B, and the horizontal rib 12 of the protrusion portion 13. The accumulated cooling water then passes through the gap 134 between the first upper plate portion 132A and the second upper plate portion 132B and is guided into the flow hole 30a of the head gasket 30.

[0058] In Figure 8(c), the protrusion 13 is a plate extending in the flow direction and is formed to overlap the flow hole 30a of the head gasket 30 in the vertical direction. This protrusion 13 is formed to be located approximately at the center in the vertical direction between the upper end 11c of the main body 11 and the transverse rib 12. In the spacer 10 of Figure 8(c), the vertical rib 14 concentrates the flow of cooling water to the upper side of the transverse rib 12, but the protrusion 13 has little effect in restricting the flow of cooling water, so although its effect in guiding the cooling water to the flow hole 30a of the head gasket 30 is small, it has the effect of reducing variations in cooling performance by reducing dimensional variations in the cooling water flow path 3 during processing and suppressing deformation of the main body 11.

[0059] The spacers 10 and 10A described above are not limited to the embodiments described above, their modifications, or those shown in the illustrations. In each embodiment, the protrusion 13 may be provided between a plurality of cylinder bores 2, 2 and contact the cylinder bore side wall 3c between the cylinder bores 2, 2 when the pressing means 15 is enlarged. Alternatively, the protrusion 13 may not be provided between a plurality of cylinder bores 2, 2, but contact the cylinder bore side wall 3c at a position slightly away from the cylinder bores 2, 2 when the pressing means 15 is enlarged. Even if the protrusion 13 is provided at a position slightly away from the cylinder bores 2, 2, it will still have a cooling effect between the cylinder bores 2, 2.

[0060] In the first embodiment, the vertical ribs 14 are configured to contact the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 is expanded, but they may be configured not to contact. In the second embodiment, the vertical ribs 14 are configured not to contact the cylinder bore side wall 3c of the cooling water passage 3 when the pressing means 15 is expanded, but they may be configured to contact. Furthermore, when the vertical ribs 14 contact the cylinder bore side wall 3c of the cooling water passage 3, it is desirable that the pressing means 15 overlap at least a part of the vertical ribs 14 with the main body portion 11 in the thickness direction, but it is not limited to this. Also, if multiple protrusions 13 are provided on a single spacer 10, 10A, each protrusion 13 may have a different configuration, and the configurations of the horizontal ribs 12 and vertical ribs 14 may also differ accordingly. In spacers 10 and 10A, vertical ribs 14 are provided at the connecting portion 111 located between adjacent arc portions 110, 110 of the main body portion 11, but the spacers are not limited to this and can be provided wherever the flow of cooling water needs to be restricted. The spacers 10 and 10A are configured to allow desired restriction or guidance of the cooling water flowing through the cooling water passage 3 by water flow control, and to adequately cool the cylinder bore 2. [Explanation of Symbols]

[0061] A Internal Combustion Engine 1 Cylinder Block 2 Cylinder bore 3 Cooling water flow path 3a Arc-shaped part 3b Waist-shaped section 3c Cylinder bore side wall 3D anti-cylinder bore sidewall 10,10A Spacer 11 Main body 11a Opposite surface 11b Anti-cylinder bore surface 110 Arc section 111 Connection part 111a Opposite side 111b Anti-cylinder bore surface 12 Transverse Ribs 13 Convex part 14 vertical ribs 15, 15A, 15B Pressing means 20 Cylinder bore wall 20a Flow hole 30 Head gasket 30a Flow hole

Claims

1. A spacer that is positioned within a cooling water passage in the cylinder block of an internal combustion engine, surrounding multiple cylinder bores, and which restricts the flow of cooling water, A main body portion formed to conform to the shape of the cooling water passages of a plurality of adjacent cylinder bores, The main body portion has transverse ribs that protrude toward the cylinder bore side and are formed along the flow direction of the cooling water passage, dividing the cooling water passage vertically and horizontally. A protrusion is provided on the upper side of the transverse rib and is in contact with the side wall of the cylinder bore of the cooling water passage, The system includes a pressing means that presses the main body toward the cylinder bore to bring the transverse rib into contact with the side wall of the cylinder bore, The pressing means is provided on the anti-cylinder bore surface of the main body, which is the surface opposite to the surface facing the cylinder bore, and is provided at a position that overlaps with the protrusion in the thickness direction of the main body.

2. A spacer that is placed in a cooling water passage that surrounds a plurality of cylinder bores in the cylinder block of an internal combustion engine and restricts the flow of cooling water, A main body portion formed to conform to the shape of the cooling water passages of a plurality of adjacent cylinder bores, The main body portion has transverse ribs that protrude toward the cylinder bore side and are formed along the flow direction of the cooling water passage, dividing the cooling water passage vertically and horizontally. A protrusion is provided on the upper side of the transverse rib and is in contact with the side wall of the cylinder bore of the cooling water passage, The system includes a pressing means that presses the main body toward the cylinder bore to bring the transverse rib into contact with the side wall of the cylinder bore, The pressing means is provided on the anti-cylinder bore surface of the main body, which is the surface opposite to the surface facing the cylinder bore. The spacer is characterized in that the protrusions are provided between a plurality of cylinder bores.

3. In claim 2, When the pressing means presses the main body toward the cylinder bore, it further has longitudinal ribs that approach or contact the side wall of the cylinder bore of the cooling water passage, The spacer is characterized in that the vertical ribs are provided below the horizontal ribs in the main body.

4. In claim 3, The longitudinal ribs are provided in the cooling water passages between the plurality of cylinder bores, The pressing means is provided on the surface opposite the cylinder bore and is positioned to overlap with the longitudinal ribs in the thickness direction of the main body, characterized in that it is a spacer.

5. In any one of claims 2 to 4, The pressing means is provided on the surface opposite the cylinder bore and is positioned to overlap with the protrusion in the thickness direction of the main body, characterized in that it is a spacer.

6. In any one of claims 2 to 4, The spacer is characterized in that the protrusions guide the cooling water into flow holes provided between the plurality of cylinder bores in the flow direction of the cooling water passage.

7. In any one of claims 1 to 4, The pressing means is made of a porous material having the characteristic of expanding in the thickness direction from a compressed state when a predetermined external factor is applied, and is a spacer characterized in that it is in a compressed state before being placed in the cooling water channel.

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