JP2007127066A - Cooling structure and water passage forming member for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure for an internal combustion engine efficiently cooling a part between cylinder bores without a large scale design change of a conventional cylinder block, and a channel forming member for providing the structure for a multiple cylinder engine provided with a cooling water passage between cylinder bores. <P>SOLUTION: A post-fit water guide 12 is applied to a water jacket 6 formed in the cylinder block, and relatively high speed cooling water flow heading upward (toward a combustion chamber side from a crank shaft side along a cylinder axial direction) is formed in a Siamese jacket region B of a water jacket 6 to increase cooling performance of a Siamese part upper end part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure for cooling an internal combustion engine such as an automobile engine with cooling water and a water channel forming member disposed in a cooling water passage (hereinafter referred to as a water jacket) in order to obtain the structure. In particular, the present invention relates to measures for efficiently cooling an internal combustion engine.

  Conventionally, in a multi-cylinder engine used for automobiles, etc., cylinder bores adjacent to each other in a cylinder block are connected in order to reduce the size and weight and shorten the overall length (length in the cylinder row direction). The so-called “Siamese structure” is known.

  The cylinder block having this siamese structure has a short dimension between the cylinder bores (the area where adjacent cylinder bores are closest to each other, hereinafter referred to as “siamese part”). There is no passage. For this reason, in particular, there is a concern about the temperature rise in the siamese portion. In particular, in the siamese portion around the upper end of the cylinder block that directly receives heat from the combustion chamber, the temperature becomes considerably high.

  In the case of a cylinder block made of aluminum alloy, which is becoming popular in recent years, there is a possibility that the material strength cannot be sufficiently obtained when the temperature exceeds 200 ° C. However, when a siamese structure is adopted for this aluminum alloy cylinder block, There is a possibility that the upper end of the siamese portion may exceed 200 ° C., and there is a concern that thermal distortion may occur due to a temperature difference from the surroundings. When this thermal distortion occurs, the roundness of the cylinder bore deteriorates, and lubricating oil flows into the combustion chamber from the gap between the piston ring and the inner wall of the cylinder (the inner surface of the cylinder liner), resulting in increased oil consumption or blow-by gas. This leads to a problem such as a large increase in the amount of. FIG. 13 shows an example of the temperature distribution around the siamese portion (temperature distribution in a cross section perpendicular to the cylinder row direction) when an engine using a cylinder block having a siamese structure is operated. FIG. 14 shows an example of the flow velocity distribution in the water jacket of the same portion when the coolant is circulated along the cylinder row direction. As apparent from FIG. 13, the upper end of the siamese portion reaches nearly 200 ° C., and there is a concern about deterioration of material strength and thermal distortion in this portion. The cooling performance of the cylinder block depends on the flow rate of the cooling water in the water jacket. As can be seen from FIG. 14, the flow rate of the cooling water is low in the vicinity of the upper end portion of the cylinder block. This is one of the factors that cannot provide sufficient cooling.

In view of this point, the following Patent Document 1 and Patent Document 2 have been proposed. In Patent Document 1, both ends of a plate kelen cast so as to cross the siamese part are projected into the water jacket, and a water passage hole penetrating in the horizontal direction is formed in a portion close to the siamese part in the projected part. A configuration is disclosed. In other words, the cooling water is introduced into the vicinity of the siamese portion by guiding the cooling water to the water passage hole, thereby improving the cooling efficiency of the siamese portion. Patent Document 2 discloses a configuration in which a cooling water passage that is independent of the water jacket and extends in the cylinder central axis direction (vertical direction) is integrally formed in the constricted portion of the siamese portion.
Japanese Utility Model Publication No. 6-83940 Japanese Patent Laid-Open No. 4-43845

  However, in the configuration disclosed in Patent Document 1, the total length of the cylinder block is increased by the thickness dimension of the plate kelen interposed between the cylinder bores (for example, in the case of an in-line 6-cylinder engine, the total length of the cylinder block is 5 times longer than the thickness of keren), the original purpose of the Siamese structure cannot be achieved.

  In addition, in the thing of this patent document 1, since cooling water flows in a cylinder row direction (horizontal direction), the cooling performance around the upper end part of a specific cylinder will be inferior. More specifically, for example, in the case of an in-line four-cylinder engine, the cooling water from the radiator flows in the horizontal direction in the water jacket from the first cylinder to the fourth cylinder. At this time, cooling water having a relatively low temperature flows around the upper end portion of the siamese portion between the first cylinder and the second cylinder. The temperature of the cooling water and the temperature of the siamese portion Since the difference is large, the siamese portion is efficiently cooled. The cooling water that has cooled the periphery of the upper end portion of the siamese portion flows in the horizontal direction as it is, and after cooling the periphery of the upper end portion of the siamese portion between the second cylinder and the third cylinder, It flows into the vicinity of the upper end portion of the siamese portion between the fourth cylinder. At this time, the cooling water has already reached a considerably high temperature, and the difference between the temperature of the cooling water and the temperature of the siamese part (the siamese part between the third and fourth cylinders) is extremely small. It has become. For this reason, it becomes difficult to sufficiently cool the vicinity of the upper end portion of the siamese portion between the third cylinder and the fourth cylinder.

  On the other hand, in the one disclosed in Patent Document 2, since the above-described plate keren and water channel do not exist between the cylinder bores, the overall length of the cylinder block can be shortened, but only for the siamese portion independent of the water jacket. It is necessary to form a new cooling water passage inside the cylinder block. In other words, it is necessary to integrally form two independent coolant passages in the cylinder block. For this reason, it is necessary to make a significant design change with respect to the conventional cylinder block, which is not practical.

  The present invention has been made in view of such a point, and the object of the present invention is to make a significant design change to a conventional cylinder block for a multi-cylinder engine that does not have a cooling water passage between the cylinder bores. An object of the present invention is to provide a cooling structure for an internal combustion engine capable of efficiently cooling between cylinder bores without being required, and a water channel forming member for obtaining the structure.

-Principle of solving the problem-
The solution principle of the present invention devised to achieve the above object is to apply a water channel forming member that is retrofitted to a water jacket (cooling water passage) formed in the cylinder block to cool the vicinity of the siamese portion. A relatively high-speed cooling water flow is formed in the water passage upward (from the crankshaft side to the combustion chamber side along the cylinder axis direction) to improve the cooling performance for the upper end portion of the siamese portion. .

-Solution-
Specifically, the present invention relates to an internal combustion engine that cools a cylinder by flowing cooling water along a cylinder row direction with respect to a cooling water passage formed so as to surround an outer periphery of a cylinder barrel of a cylinder block having a siamese structure. A cooling structure is assumed. With respect to the cooling structure of the internal combustion engine, a water channel forming member is disposed in a cooling water passage in the vicinity of the siamese portion, which is a boundary portion between adjacent cylinder bores. Then, by these water channel forming members, the cooling water passage near the siamese portion is divided into an inner passage on the siamese portion side and an outer passage on the cylinder block outer wall side, and the cooling water that has flowed into the cooling water passage near the siamese portion Is introduced into the inner passage and is circulated along the inner passage from the crankshaft side in the cylinder axial direction toward the combustion chamber side.

  With this specific matter, when the cooling water flowing in the cooling water passage along the cylinder row direction reaches the vicinity of each siamese portion, a part thereof flows into the inner passage that is partitioned by the water passage forming member. Since this inner passage is a part of the cooling water passage in the vicinity of the siamese portion (isolated from the outer passage), the flow passage area is relatively small, and the flow rate of the cooling water flowing into this inner passage is high. The cooling water is circulated from the crankshaft side (position away from the combustion chamber) toward the combustion chamber side in the cylinder axial direction. For this reason, comparatively low temperature cooling water is flowed toward the combustion chamber side (high temperature part) in the vicinity of the siamese part, and the siamese part can be effectively cooled. In addition, since the cooling water can flow at a high flow rate in the inner passage as described above, the cooling effect of the siamese portion can be further enhanced. As described above, according to the present solution, the cooling water passage crossing the siamese portion is not formed, and the relatively low temperature cooling water flowing in the vicinity of the lower end of the cooling water passage is passed through the upper end of the siamese portion. Therefore, the upper end portion (combustion chamber side) of the cylinder block can be efficiently cooled while shortening the overall length of the cylinder block.

  More specific examples of the shape of the cooling water passage in the vicinity of the siamese portion include the following. That is, the region on the combustion chamber side in the cylinder axial direction in the cooling water passage in the vicinity of the siamese portion is divided into the inner passage and the outer passage by the water passage forming member, and the crank in the cylinder axial direction in the cooling water passage near the siamese portion A part of the cooling water that has flowed into the shaft side region is introduced into the inner passage and is circulated along the inner passage from the crankshaft side in the cylinder axial direction toward the combustion chamber side.

  According to this, it is possible to reliably contribute to the cooling of the upper end portion of the siamese portion with the relatively low temperature cooling water flowing in the crank side region in the cylinder axial direction in the cooling water passage in the vicinity of the siamese portion. Further, in the region on the crankshaft side, the cooling water passage is not divided and a relatively large flow passage area is secured. Therefore, in this region, the pressure loss with respect to the cooling water flow can be suppressed and the cooling water speed can be kept high.As a result, the cooling water speed flowing through the inner passage can also be increased, and the upper end portion of the siamese portion It can be cooled effectively.

  The following structure is mentioned as what specifies the flow of the cooling water after passing through the inner passage. A cylinder head is disposed above the cylinder block, and a cooling water passage formed inside the cylinder head is communicated with the inner passage. Then, the cooling water flows along the inner passage from the crankshaft side in the cylinder axial direction toward the combustion chamber side, and is then introduced into the cooling water passage of the cylinder head.

  According to this, the cooling water that has passed through the inner passage quickly flows out to the cylinder head side, and the cooling water does not stay in the combustion chamber side portion of the inner passage. For this reason, the cooling water flows from the inner passage to the cooling water passage of the cylinder head while maintaining a relatively high speed, and the siamese portion in the vicinity of the combustion chamber can be effectively cooled.

  Further, a water channel forming member disposed in the cooling water passage in order to obtain the cooling structure is also within the scope of the technical idea of the present invention. And the following are mentioned as a concrete structure of this water channel formation member.

  First, the water channel forming member is provided with a dividing portion that divides the cooling water passage in the vicinity of the siamese portion into an inner passage and an outer passage, and the wall surface located on the cylinder bore side of the inner wall surface of the water passage forming the cooling water passage And a plurality of abutting portions each abutting against a wall surface located outside the cylinder block. And the water channel formation member is arrange | positioned in the cooling water channel in the state in which the movement of the direction orthogonal to a cylinder axial direction was prevented by contact | abutting of these each part.

  Also, the water channel is formed so that the lower end of the water channel forming member abuts the bottom surface of the cooling water passage near the siamese portion, and the upper end of the water channel forming member contacts the lower surface of the gasket or cylinder head disposed above the cylinder block. The length dimension along the cylinder axial direction of the member is set.

  According to these specific matters, it becomes possible to mount the water channel forming member so as to be immovable with respect to the cooling water passage without requiring a special mounting member or mounting work, and the cross-sectional shape of each passage can be maintained. Therefore, the cooling efficiency can be improved with the stabilization of the cooling water flow.

  Furthermore, when the outer surface is covered with a material having elasticity as the structure of the water channel forming member, the water channel forming member is arranged in the cooling water channel by elastic deformation of the coating material according to the inner wall of the cooling water channel. The installation state can be stably maintained, and the water tightness at each contact portion is ensured satisfactorily, the cooling water leaks between the passages, and the cooling effect can be enhanced.

  Moreover, the following is mentioned as a structure in consideration of workability | operativity in the case of arrange | positioning a several water path formation member in a cooling water flow path. That is, a plurality of water channel forming members are integrated with each other by using this spacer for the one provided with a spacer that restricts the flow region of the cooling water in the cooling water passage by being inserted into the cooling water passage. It is to be attached. According to this, before inserting the spacer into the cooling water passage, each water channel forming member can be attached to the spacer, and simultaneously with the operation of inserting the spacer into the cooling water passage, The water channel forming member can be disposed in the cooling water passage in the vicinity of the siamese portion, and the workability is improved.

  In the present invention, the cooling water flowing through the cooling water passage is circulated from the crankshaft side toward the combustion chamber side along the cooling water passage in the vicinity of the siamese portion having a relatively small flow passage area. For this reason, it becomes possible to flow the cooling water having a relatively low temperature in the vicinity of the siamese portion at a high flow rate, so that the cooling effect of the siamese portion can be enhanced and the cylinder block can be cooled uniformly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case will be described in which the present invention is applied to an in-line four-cylinder gasoline engine for automobiles equipped with a cylinder block having a siamese structure.

−Cylinder block configuration−
FIG. 1 is a plan view of a cylinder block 1 showing the cylinder bores 4, 4,... Of the in-line four-cylinder engine according to the present embodiment and the periphery thereof, and the arrangement of cylinder rows and a water jacket (cooling water passage) 6 is shown. (The outer edge shape of the cylinder block 1 is omitted). FIG. 2 is a perspective view showing a water guide (water channel forming member) 12 mounted in the water jacket (cooling water passage) 6 which is a feature of the present embodiment. In the following description, the cylinder located at the left end in FIG. 1 is the first cylinder # 1, the cylinder located on the right side is the second cylinder # 2, and the cylinder located on the right side is the third cylinder # 1. The cylinder # 3 and the cylinder located at the right end will be described as the fourth cylinder # 4. Further, the lower side in FIG. 1 will be described as the intake side, and the upper side will be described as the exhaust side. The cylinder number and the form of intake and exhaust are not limited to this.

  A cylinder block 1 which is a constituent member of an in-line four-cylinder engine according to the present embodiment is made of an aluminum alloy, and as shown in FIG. 1, four cylinder barrels 2, 2,. A Siamese cylinder barrel 3 formed integrally is provided. Further, a cylinder liner 5 (see FIG. 5 which is a sectional view corresponding to the line V-V in FIG. 3) forming the inner surface of the cylinder bore 4 is cast on the inner surface of each cylinder barrel 2, 2,. It is rare.

  Moreover, the cylinder block 1 which concerns on this embodiment is comprised by the open deck type. That is, the water jacket 6 is opened to the top surface of the cylinder block 1 which is an assembly surface of the cylinder head 10 (see FIG. 3 which is a cross-sectional view taken along line III-III in FIG. 1). The water jacket 6 is formed between the outer wall of the cylinder block 1 and the siamese cylinder barrel 3 so as to surround substantially the entire circumference of the siamese cylinder barrel 3. For this reason, as shown in FIG. 1, the water jacket 6 includes a main jacket region A extending along the cylindrical surface shape that is the outer peripheral surface of each cylinder barrel 2, 2,. A siamese jacket region B formed as a constricted part (region formed by a substantially V-shaped concave part in a plan view) recessed toward the space (siamese part 20).

  Further, in the water jacket 6, a cooling water inlet passage 61 into which cooling water from the water pump is introduced is formed at one end side in the cylinder row direction (left end side in FIG. 1), that is, in the vicinity of the first cylinder # 1. Has been. And as a main flow of the cooling water in the water jacket 6, the cooling water introduced from this cooling water inlet passage 61 is one side of the Siamese cylinder barrel 3 along the arrangement direction of the cylinder barrels 2, 2,. 1 flows from the first cylinder # 1 toward the fourth cylinder # 4 (see arrow α in FIG. 1), and flows along the outer periphery of the fourth cylinder # 4. After the direction is reversed (see arrow β in FIG. 1), the other side of the siamese cylinder barrel 3 (the exhaust side which is the upper side in FIG. 1) is again arranged along the arrangement direction of the cylinder barrels 2, 2,. It flows toward the first cylinder # 1 (see arrow γ in FIG. 1). Other flows (branch flows) will be described later. Then, the cooling water that has returned to the periphery of the first cylinder # 1 is led out toward the cylinder head 10 through outlets 8 and 9 formed in the vicinity of the first cylinder # 1.

  Further, a gasket 11 (see FIG. 3) is interposed between the cylinder block 1 and the cylinder head 10. In the siamese jacket region B, a cooling water introduction hole 10a is formed in the cylinder head 10 and the gasket 11. 11a are formed, and in this Siamese jacket region B, it is possible to lead out the cooling water from the cylinder block 1 toward the cylinder head 10 (see arrow L1 in FIG. 3).

-Configuration of the water guide 12-
Next, the water guide 12 mounted in the water jacket 6 will be described. As described above, FIG. 2 is a perspective view showing the water guide 12. 4 is a plan view of the mounting portion of the water guide 12, FIG. 5 is a cross-sectional view of the position corresponding to line VV in FIG. 3, and FIG. 6 is a cross-sectional view of the position corresponding to line VI-VI in FIG. 7 is a cross-sectional view of a position corresponding to the line VII-VII in FIG.

  As shown in these drawings, the water guide 12 is mounted on each of the siamese jacket regions B, B,. Since the engine according to this embodiment has four cylinders, the water guides 12, 12,... Are mounted in a total of six Siamese jacket regions B, B,. Each of the water guides 12, 12,... And the mounting state thereof are the same. Therefore, here, one water guide 12 and its mounting location will be described as a representative.

  As shown in FIG. 2, the water guide 12 includes a main body part (divided part) 13 for partitioning a cooling water flow path in the siamese jacket region B, and a leg part 14 extending downward from the lower end of the main body part 13. And are formed integrally. The main body portion 13 and the leg portion 14 are configured such that the entire surface of a core material 13a, 14a made of metal (for example, a light metal such as aluminum) or resin is covered with rubber surface materials 13b, 14b ( (See FIG. 3). Hereinafter, the main body 13 and the leg 14 will be described.

<Main body 13>
As shown in FIGS. 2 and 4 to 6, the main body portion 13 includes a pair of upper and lower horizontal plate portions (partition portions extending in the horizontal direction) 15 having a shape substantially matching the planar shape of the Siamese jacket region B. 16 and a plate-like vertical plate portion (partition portion extending in the vertical direction) 17 extending in the vertical direction so as to connect the edges on the side of the siamese portion 20 of these plate portions 15 and 16.

  Each of the horizontal plate portions 15 and 16 has substantially the same shape, and is in contact with each part of the inner surface of the water jacket 6 constituting the Siamese jacket region B and is fitted into the Siamese jacket region B. ing. Specifically, each of the horizontal plate portions 15 and 16 includes first and second contact portions 15a, 15b, 16a, which are in contact with the outer peripheral surfaces of the cylinder barrels 2 and 2 located on both sides of the siamese jacket region B. 16b, and third abutting portions (leg portions extending in the horizontal direction from the vertical plate portion 17) 15c and 16c that abut against the side surface of the head bolt boss 18 in which the head bolt holes 18a are formed. The contact of the contact portions 15a, 15b, 15c, 16a, 16b, and 16c (contact with the outer peripheral surface of the cylinder barrels 2 and 2 and the side surface of the head bolt boss 18) prevents the water guide 12 from moving in the horizontal direction. ing.

  The vertical plate portion 17 that connects the horizontal plate portions 15 and 16 divides the siamese jacket region B into an inner passage B1 on the siamese portion 20 side and an outer passage B2 on the head bolt boss 18 side. (See FIGS. 3 and 5). In this case, the first and second end portions of the vertical plate portion 17 in the cylinder row direction and continuous with the first and second contact portions 15a, 15b, 16a, 16b of the horizontal plate portions 15, 16 are used. Since the contact portions 17a and 17b contact the outer peripheral surfaces of the cylinder barrels 2 and 2 (see FIG. 5), in the siamese jacket region B, the inner passage B1 and the outer passage B2 are completely separated from each other. It will be configured as a passage. Moreover, the upper surface of the upper plate portion 15 is in contact with the lower surface of the gasket 11 (see FIG. 3).

  Since the main body 13 of the water guide 12 is disposed in the upper region of the siamese jacket region B in this way, the outer passage B2 communicates with the main jacket region A only at both ends in the cylinder row direction. . Therefore, as indicated by an arrow U in FIG. 2, the cooling water that has reached the siamese jacket region B after flowing through the upper region of the main jacket region A flows through the outer passage B2, and then the downstream main jacket region A. It is designed to flow toward

  On the other hand, the inner passage B1 is a passage extending along the cylinder axis direction, the cooling water introduction holes 11a, 10a formed in the lower region of the siamese jacket region B and in the gasket 11 and the cylinder head 10 at the upper ends. To communicate with each other. Therefore, as shown by an arrow L1 in FIG. 2, a part of the cooling water that has reached the siamese jacket region B after flowing through the lower region of the main jacket region A is directed from the lower side to the upper side. The flow then flows out through the cooling water introduction hole 11a of the gasket 11 and the cooling water introduction hole 10a of the cylinder head 10 toward the cooling water flow path in the cylinder head 10 (see arrow L1 in FIG. 3). .

<Leg 14>
2, 3 and 7, the leg portion 14 extends vertically downward from the edge on the side of the siamese portion 20 on the lower surface of the lower horizontal plate portion 16, and has a horizontal sectional shape. Is rectangular (see FIG. 7) and has a cross-sectional shape that is significantly smaller than the horizontal plate portions 15 and 16. Therefore, each side surface of the leg portion 14 is arranged in a state where it does not contact the outer peripheral surface of the cylinder barrel 2 and the side surface of the head bolt boss 18.

  Further, the lower end of the leg portion 14 is in contact with the bottom surface of the siamese jacket region B. Since the upper surface of the upper horizontal plate portion 15 is in contact with the lower surface of the gasket 11 as described above, the water guide 12 is sandwiched between the lower surface of the gasket 11 and the bottom surface of the water jacket 6 (Siamese jacket region B). It is arranged in a state where the movement in the vertical direction is prevented.

  In this way, the leg portion 14 of the water guide 12 is disposed in the lower region of the siamese jacket region B. In this part, the siamese jacket region B communicates with the main jacket region A at both ends in the cylinder row direction. is doing. That is, a part of the cooling water that has reached the siamese jacket region B after flowing through the lower region of the main jacket region A flows into the inner passage B1 as described above (see arrow L1 in FIG. 2), while the other cooling water. As shown by arrows L2 and L3 in FIG. 2, it flows in the cylinder row direction as it is and flows out toward the main jacket region A on the downstream side.

-Effect of the embodiment-
Next, the effect of this embodiment will be described while comparing the flow of cooling water in a conventional water jacket with the flow of cooling water in this embodiment. FIG. 8 is a cross-sectional view showing the periphery of a siamese portion of a conventional water jacket (a diagram corresponding to FIG. 5), and FIG. 9 is a vertical cross-sectional view showing the periphery of a siamese portion of a conventional water jacket (corresponding to FIG. 3). Figure).

  First, in the conventional water jacket a, the flow rate of the cooling water in the region I in FIGS. 8 and 9 is high. This area | region I is an area | region of the outer side of the water jacket a, and also becomes an area | region where the height position is low (the water jacket is deep). For this reason, it is difficult to cool the whole cylinder barrel b uniformly, in particular, to effectively cool the upper end portion of the cylinder barrel b close to the combustion chamber. Further, it is possible to increase the flow velocity in this portion by reducing the opening area of the water hole d formed in the gasket c (region II in FIG. 9). However, it is difficult to extend the region II having a high flow velocity to a wide range of the upper end portion of the cylinder barrel b, and even if this means is used, it is difficult to uniformly cool the entire cylinder barrel b.

  On the other hand, in the present embodiment, the cooling water can flow at a uniform and high flow rate from the lower end to the upper end of the inner passage B1 defined by the main body 13 of the water guide 12. . Moreover, this cooling water flows in the vicinity of the siamese portion 20. Furthermore, the cooling water flowing into the inner passage B1 has a relatively low temperature flowing through the lower region of the main jacket region A and the siamese jacket region B. Therefore, in particular, it is possible to effectively cool the upper end portion of the cylinder barrel 2 that is close to the combustion chamber and easily reaches a high temperature, and the entire Siamese cylinder barrel 3 can be uniformly cooled.

  In the case of this embodiment, since the horizontal cross-sectional shape of the inner passage B1 (the shape of the cross section perpendicular to the flow direction of the cooling water) is substantially uniform, the high flow rate of the cooling water in the inner passage B1. Can be stably maintained, and the entire Siamese cylinder barrel 3 can be uniformly cooled.

  Furthermore, since the cooling water that has passed through the inner passage B1 can flow out quickly to the cylinder head 10, the cooling water does not stay in the upper end portion of the inner passage B1. For this reason, the cooling water flows from the inner passage B1 to the cooling water passage of the cylinder head 10 while maintaining a relatively high speed, and the upper end portion of the cylinder barrel 2 can be effectively cooled. Become.

  The water guide 12 according to this embodiment can be fixed in position when the gasket 11 and the cylinder head 10 are assembled to the cylinder block 1 in a state where the water guide 12 is disposed in each of the siamese jacket regions B, B,. ing. For this reason, the special operation | work for fixing the water guide 12 inside the water jacket 6 is unnecessary, and workability | operativity is favorable. In addition, the cylinder block 1 does not require a special structure for mounting the water guide 12 and therefore does not require a significant design change from the conventional cylinder block.

(Modification)
Next, a modified example of the present invention will be described. In this modification, the above water guides 12, 12,... Are applied to those in which measures are taken to prevent the periphery of the lower end of the cylinder block 1 from being excessively cooled by the cooling water. . That is, as shown in FIG. 10 (perspective view of the spacer unit 30), the spacer 31 is used to fill the lower end region of the water jacket 6 and reduce the depth of the cooling water flow path. The water guides 12 ′, 12 ′,... Are attached to form the spacer unit 30, which is attached to the water jacket 6. This will be specifically described below.

  FIG. 11 is a view taken in the direction of arrow XI in FIG. 10, and FIG. 12 is a longitudinal sectional view (a view corresponding to FIG. 3) in a state where the spacer unit 30 is mounted in the water jacket 6. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member as the thing of embodiment mentioned above.

  As shown in these drawings, the spacer 31 is made of resin or metal, and has a shape that the plan view substantially matches the plan view shape of the water jacket 6. Further, the height dimension of the spacer 31 is substantially equal to the height dimension of the region where it is necessary to prevent the cylinder block 1 from being excessively cooled by preventing the cooling water from flowing in the water jacket 6. I'm doing it.

  Further, through holes 32, 32,... Penetrating in the height direction are formed at locations corresponding to the Siamese jacket region B in the spacer 31, and the legs of the water guide 12 ′ are formed inside the through holes 32. The water guides 12 ′, 12 ′,... Are integrally attached to the spacer 31 through the portion 14. As this mounting structure, a hook-shaped claw portion 14 c is formed at the lower end of the leg portion 14 of the water guide 12 ′, and the leg portion 14 of the water guide 12 ′ is inserted to a predetermined position of the through hole 32 of the spacer 31. At this time, the claw portion 14c is locked to the lower surface of the spacer 31 so that a structure for preventing the water guide 12 'from coming off can be obtained. Further, in the leg portion 14 of the water guide 12 ′ according to the present example, the portion inserted into the through hole 32 does not include the surface material (the rubber portion described above) 14b, and is composed only of the core material 14a. Yes.

  According to this modification, the water guides 12 ′, 12 ′,... Can be attached to the spacer 31 (sub-assembled state) before the spacer 31 is attached to the water jacket 6. .. Can be disposed in the siamese jacket regions B, B,... Of the water jacket 6 and the workability is good. . Further, as described above, the portion inserted into the through hole 32 in the leg portion 14 is not provided with the surface material 14b, so that the insertion resistance is reduced, and this insertion operation can be easily performed.

(Other embodiments)
In the embodiment described above, the case where the present invention is applied to an in-line four-cylinder gasoline engine for automobiles has been described. However, the present invention is not limited to automobiles but is also applied to those used for other purposes. Is possible. Further, the number of cylinders is not limited to four, and the engine type is not limited to the in-line type, but can be applied to a V type, a horizontally opposed type, and the like.

  Moreover, in the said embodiment, although the water guide 12 was made into the integrally molded product, it is good also as an assembly part formed by combining several members.

It is a top view of a cylinder block showing each cylinder bore of an engine concerning an embodiment, and its peripheral part. It is a perspective view which shows a water guide. It is sectional drawing along the III-III line in FIG. It is a top view of the mounting part of a water guide. It is sectional drawing of the position corresponding to the VV line in FIG. It is sectional drawing of the position corresponding to the VI-VI line in FIG. It is sectional drawing of the position corresponding to the VII-VII line in FIG. It is a cross-sectional view showing the periphery of a siamese portion of a conventional general water jacket. It is a longitudinal cross-sectional view which shows the siamese part periphery of the conventional common water jacket. It is a perspective view which shows the spacer unit in a modification. It is a XI arrow line view in FIG. It is a longitudinal cross-sectional view in the state with which the spacer unit was mounted | worn in the water jacket. It is a figure which shows an example of the temperature distribution around the siamese part in a prior art example. It is a figure which shows an example of the cooling water flow velocity distribution in the water jacket in a prior art example.

Explanation of symbols

1 Cylinder block 3 Siamese cylinder barrel 4 Cylinder bore 6 Water jacket (cooling water passage)
10 Cylinder head 11 Gasket 12 Water guide (water channel forming member)
13 Main body (divided part)
15a, 15b, 16a, 16b Contact portion 20 Siamese portion 31 Spacer B1 Inner passage B2 Outer passage

Claims (7)

In a cooling structure of an internal combustion engine that cools a cylinder by flowing cooling water along a cylinder row direction with respect to a cooling water passage formed so as to surround a cylinder barrel outer periphery of a cylinder block having a siamese structure,
A water passage forming member is provided in each of the cooling water passages in the vicinity of the siamese portion, which is a boundary portion between the cylinder bores adjacent to each other. Divided into a passage and an outer passage on the cylinder block outer wall side, a part of the cooling water flowing into the cooling water passage in the vicinity of the siamese portion is introduced into the inner passage, and the crank in the cylinder axial direction is introduced along the inner passage. A cooling structure for an internal combustion engine, wherein the cooling structure is configured to circulate from a shaft side toward a combustion chamber side. In the internal combustion engine cooling structure according to claim 1,
A region on the combustion chamber side in the cylinder axial direction of the cooling water passage near the siamese portion is divided into the inner passage and the outer passage by the water passage forming member, and the crank in the cylinder axial direction of the cooling water passage near the siamese portion is divided. A portion of the cooling water that has flowed into the shaft side region is introduced into the inner passage and is circulated along the inner passage from the crankshaft side in the cylinder axial direction toward the combustion chamber side. A cooling structure of an internal combustion engine characterized by the above. In the internal combustion engine cooling structure according to claim 1 or 2,
A cylinder head is disposed on the upper side of the cylinder block, and a cooling water passage formed inside the cylinder head communicates with the inner passage, and the cooling water passes along the inner passage along the cylinder axis. A cooling structure for an internal combustion engine, which is introduced into a cooling water passage of a cylinder head after flowing from a crankshaft side in a direction toward a combustion chamber side.   A water passage forming member used in the cooling structure for an internal combustion engine according to claim 1, 2, or 3, wherein a cooling water passage in the vicinity of the siamese portion is divided into an inner passage and an outer passage. A plurality of abutting portions that abut on the wall surface located on the cylinder bore side and the wall surface located on the outer side of the cylinder block among the inner wall surfaces of the water channel forming the passage are provided. A water channel forming member, wherein the water channel forming member is disposed in the cooling water channel in a state where movement in a direction orthogonal to the direction is prevented.   4. A water channel forming member used in a cooling structure for an internal combustion engine according to claim 1, wherein the lower end portion is disposed on the bottom surface of the cooling water passage near the siamese portion and the upper end portion is disposed on the upper side of the cylinder block. A water channel forming member characterized in that a length dimension along a cylinder axial direction is set so as to abut against a lower surface of the gasket or cylinder head. In the water channel forming member according to claim 4 or 5,
A water channel forming member characterized in that an outer surface is covered with a material having elasticity. In the water channel forming member according to claim 4, 5 or 6,
A plurality of spacers are integrally attached to a spacer that regulates the flow area of the cooling water in the cooling water passage by being inserted over substantially the entire circumference of the inside of the cooling water passage. A water channel forming member.

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