JP5062071B2 - Internal combustion engine cylinder block - Google Patents

Description

  The present invention relates to a structure of a cylinder block used in an internal combustion engine such as an automobile engine.

  A cylinder block used in an internal combustion engine such as an automobile engine is provided with a water jacket (cooling water passage) for circulating cooling water pumped by a water pump. The water jacket is formed so as to surround the cylinder bore wall in order to cool the cylinder bore wall (outer wall of the cylinder bore) heated by the heat from the combustion chamber.

In the cylinder block, it is important to effectively cool the upper part of the cylinder bore wall close to the combustion chamber. Conventionally, a technique has been proposed in which a rectifying member is provided on the water jacket to guide cooling water upward in the cylinder axial direction (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 62-135842

  However, in the conventional example shown in Patent Document 1, the rectifying member is made of a member different from the cylinder bore wall, so the following points are concerned. That is, since the operation | work which attaches a baffle member to the predetermined position of a cylinder bore wall is needed, the manufacturing cost of a cylinder block will increase correspondingly. Further, there is a possibility that the position of the rectifying member with respect to the cylinder bore wall may fluctuate, and there is a concern that the flow of cooling water changes and a desired cooling performance cannot be obtained.

  The present invention has been made in view of such a problem, and can effectively cool the upper portion of the cylinder bore wall close to the combustion chamber, and is a low-cost and highly reliable internal combustion engine cylinder block. The purpose is to provide.

In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention includes a cooling water passage formed so as to surround a cylinder bore of a multi-cylinder internal combustion engine, and is configured to introduce cooling water into the cooling water passage from one end side in the cylinder row direction. In the cylinder block of the engine, the cooling water passage is provided with a plurality of protrusions for forming a cooling water flow directed upward in the cylinder axial direction, and each of the protrusions includes an exhaust-side portion of the cooling water passage and A portion provided only in the exhaust side portion of the intake side portion and provided in each cylinder excluding the cylinder arranged at the most end side in the cylinder row direction and provided with the projections of the cooling water passage Then, the depth along the cylinder axis direction of the cooling water passage is shallower and the depth becomes shallower from the upstream side to the downstream side in the flow direction of the cooling water as compared with the portion where no protrusion is provided. And Tsu, said each projection is characterized in that integrally formed on the outer wall at the same time the cylinder bore during the casting of the cylinder block.

According to the above configuration, since the cooling water introduced into the cooling water passage by the plurality of protrusions is guided upward in the cylinder axial direction, the upper part of the outer wall of the cylinder bore near the combustion chamber can be effectively cooled. it can. Further, since the plurality of protrusions are formed without special machining, the plurality of protrusions can be easily manufactured as compared with the conventional example in which the rectifying unit is configured by a separate member. The manufacturing cost of the block can be reduced. Moreover, since the plurality of protrusions are formed integrally with the cylinder block, the position of the cylinder bore with respect to the outer wall does not vary. Therefore, a stable rectifying action by the plurality of protrusions can be obtained, and a highly reliable cylinder block can be obtained.

In addition, since the plurality of protrusions are manufactured simultaneously when the cylinder block is cast, the plurality of protrusions can be easily manufactured, and the manufacturing cost of the cylinder block can be reduced.

In addition, the portion of the cooling water passage where the protrusions are provided has a shallower depth along the cylinder axis direction of the cooling water passage than the portion where the protrusions are not provided. Since the flow path area of the cooling water is reduced at the portion where each of the protrusions is provided , the flow rate of the cooling water increases as the cooling water passes through the portion . Thereby, the upper part of the outer wall of the cylinder bore close to the combustion chamber can be further effectively cooled.

Each of the protrusions is provided in each cylinder excluding the cylinder arranged at the most end side in the cylinder row direction, and the depth along the cylinder axial direction of the portion of the cooling water passage where the protrusions are provided. The depth becomes shallower from the upstream side to the downstream side in the flow direction of the cooling water. If the depth along the cylinder axis direction of the cooling water flow path provided on the upstream side in the flow direction of the cooling water is excessively reduced, the pressure loss increases, so that the flow rate of the cooling water decreases on the downstream side. According to this configuration, since the flow path area of the cooling water is gradually reduced from the upstream side to the downstream side in the flow direction of the cooling water, an increase in pressure loss can be avoided, and a desired flow velocity can be secured on the downstream side. It becomes possible.
Here, it is preferable that the cooling water introduced into the cooling water passage flows through a portion on the exhaust side of the cooling water passage and then flows through a portion on the intake side of the cooling water passage. The protrusions preferably extend from the bottom of the cooling water passage toward the top surface.

In the present invention, the protrusions are preferably formed at intermediate positions between the head bolt holes adjacent to each other in the cylinder row direction. In other words, each of the protrusions is provided at a position corresponding to the center of the cylinder bore in the cylinder row direction. The tightening axial force of the head bolt is transmitted to the outer wall of the cylinder bore through the bottom of the cooling water passage. In this case, as the depth of the cooling water passage is shallower, the tightening axial force of the head bolt is more easily transmitted to the outer wall of the cylinder bore, and as a result, the deformation of the cylinder bore increases. According to this configuration, since each of the protrusions is provided at a position relatively far from the head bolt hole, it is possible to suppress deformation of the cylinder bore due to the tightening axial force of the head bolt accompanying the shallowness of the cooling water passage. .

Moreover, in this invention, it is preferable that the upstream guide surface of the said each protrusion of the flow direction of the cooling water inclines toward the downstream of the said flow direction, so that it goes upwards. According to this configuration, since the cooling water by the guide surfaces of the respective projections are easily guided to above the cylinder axis direction, thereby improving the rectifying action of the respective projections. Thereby, the upper part of the outer wall of the cylinder bore close to the combustion chamber can be cooled more effectively.

According to the present invention, since the cooling water introduced into the cooling water passage by the plurality of protrusions is guided upward in the cylinder axial direction, the upper portion of the outer wall of the cylinder bore near the combustion chamber can be effectively cooled. it can. Further, since the plurality of protrusions are formed without special machining, the manufacturing cost of the cylinder block can be reduced. Moreover, since the plurality of protrusions are formed integrally with the cylinder block, the position of the cylinder bore with respect to the outer wall does not vary. Therefore, a stable rectifying action by the plurality of protrusions can be obtained, and a highly reliable cylinder block can be obtained.

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  In the following embodiment, an example in which the present invention is applied to a cylinder block used in an in-line four-cylinder gasoline engine for automobiles will be described.

  FIG. 1 is a plan view of each cylinder bore 11a, 11a,... Of the in-line four-cylinder engine according to the embodiment, and a cylinder block 10 showing the periphery thereof, in which a cylinder row and a water jacket (cooling water passage) 20 are shown. The arrangement state is shown (the outer edge shape of the cylinder block 10 is omitted). In FIG. 1, the leftmost cylinder is the first cylinder # 1, the right cylinder is the second cylinder # 2, the further right cylinder is the third cylinder # 3, and the rightmost cylinder is The cylinder located is designated as the fourth cylinder # 4. In FIG. 1, the lower side is the exhaust side, and the upper side is the intake side. However, the cylinder number and the form of intake and exhaust are examples, and are not limited thereto.

  The cylinder block 10 is made of, for example, an aluminum alloy, and includes a siamese cylinder barrel 12 in which four cylinder barrels 11, 11,... Arranged in series are integrally formed as shown in FIG. A cylinder head (not shown) is fastened to the top surface of the cylinder block 10 via a cylinder head gasket.

  The siamese cylinder barrel 12 is formed in a shape in which four cylindrical bodies that serve as the cylinder barrel 11 of each cylinder are continuously connected in series. Each cylinder barrel 11 is an outer wall portion of a cylinder bore 11a on which a piston slides. Each cylinder barrel 11 is integrally cast with a cast iron cylinder liner 11b constituting the inner surface of the cylinder bore 11a. The mechanical strength, wear resistance, heat resistance, etc. of the inner surface of the cylinder bore 11a with which the piston is slidably contacted. Is to be secured.

  A block outer wall portion 13 is disposed on the outer peripheral side of the siamese cylinder barrel 12. The block outer wall portion 13 is formed to face the siamese cylinder barrel 12 with a predetermined interval. A water jacket 20 is formed by the outer wall surface of the siamese cylinder barrel 12 and the inner wall surface of the block outer wall portion 13.

  The water jacket 20 is provided so as to surround the periphery of the Siamese cylinder barrel 12 (four cylinder barrels 11, 11,...). The water jacket 20 is opened to a deck surface that is an assembly surface (head placement surface) of the cylinder head. That is, the cylinder block 10 is configured as an open deck type. And the rectification | straightening part 22,22, ... in which the depth D (distance from a top surface to a bottom face) along a cylinder axial direction is shallow is provided in several places of the water jacket 20. As shown in FIG. Details of the rectifying unit 22 of the water jacket 20 will be described later.

  Cooling for introducing cooling water from a water pump (not shown) into the water jacket 20 on one end side (the left end side in FIG. 1) of the block outer wall portion 13 in the cylinder row direction, that is, in the vicinity of the first cylinder # 1. A water inlet 16 is formed. In this embodiment, the cooling water inlet 16 is provided in the lower part of the block outer wall part 13 (refer FIG. 2). Further, the cooling water inlet 16 is provided in a portion near the exhaust side of the block outer wall portion 13.

  In FIG. 1, the main flow (flow in the horizontal direction) of the cooling water in the water jacket 20 when viewed from above is indicated by arrows. Specifically, the cooling water flowing in from the cooling water inlet 16 is supplied to the cooling water introduction part 21 of the water jacket 20 provided in the vicinity of the cooling water inlet 16. The cooling water introduction portion 21 has a shape in which an exhaust side portion is expanded outward on one end side of the water jacket 20.

  The cooling water introduced into the cooling water introducing portion 21 of the water jacket 20 is arranged on the one side (the exhaust side which is the lower side in FIG. 1) of the siamese cylinder barrel 12 along the arrangement direction of the cylinder barrels 11 as the first cylinder #. From 1 to the fourth cylinder # 4. Next, after the flow direction of the cooling water is reversed along the outer periphery of the fourth cylinder # 4, the other side of the siamese cylinder barrel 12 is again formed along the arrangement direction of the cylinder barrels 11 (in FIG. 1). The upper intake side) flows toward the first cylinder # 1. The cooling water that has returned to the periphery of the first cylinder # 1 is then discharged from the cooling water outlet 18 disposed in the vicinity of the first cylinder # 1 toward the cylinder head. The cooling water outlets 18 are formed in the cylinder head gasket and the cylinder head, respectively, so that the cooling water can flow from the cylinder block 10 to the cylinder head.

  Moreover, head bolt holes 17, 17,... For tightening a head bolt for assembling the cylinder head integrally are formed at a plurality of locations on the block outer wall portion 13. Four head bolt holes 17 are arranged around each cylinder barrel 11 (each cylinder bore 11a). A total of ten head bolt holes 17, 17,... Are provided for the four cylinder bores 11a, 11a,. In this case, the head bolt hole 17 is disposed at a substantially symmetrical position on the intake side and the exhaust side. Two head bolt holes 17 are disposed at both ends in the cylinder row direction, and two are disposed between adjacent cylinder bores 11a and 11a (between bores). Thus, the head bolt hole 17 is provided at a position corresponding to the end of the cylinder bore 11a in the cylinder row direction, but is not provided at a position corresponding to the center (bore center) of the cylinder bore 11a. .

  Next, the rectifying unit 22 of the water jacket 20 which is a feature of this embodiment will be described in detail.

  FIG. 2 is a diagram showing the inside of the cylinder block 10 as viewed from the X2 direction in FIG. 1 and shows the shape of the water jacket 20 (the block outer wall portion 13 disposed on the front side of the water jacket 20 is omitted). is doing). 3 is a sectional view taken along line X3-X3 in FIG. 1, FIG. 4 is a sectional view taken along line X4-X4 in FIG. 1, and FIG. 5 is a sectional view taken along line X5-X5 in FIG. 6 is a cross-sectional view taken along line X6-X6 in FIG.

  As shown in FIGS. 1 to 6, the water jacket 20 is formed with a plurality (three in this embodiment) of rectifying sections 22 for forming a flow of cooling water that is directed upward in the cylinder axial direction. Specifically, the rectifying unit 22 is a portion where the depth D of the water jacket 20 is shallower than the bottom portion (FIG. 3) other than the rectifying unit 22. In other words, the plurality of protrusions extend from the bottom of the water jacket 20 toward the top surface, and the flow path area of the cooling water is restricted by the protrusions.

  In this embodiment, a rectifying unit 22 is provided on the exhaust side of the water jacket 20. As described above, since the cooling water flows in the order of the exhaust side portion of the water jacket 20 → the intake side portion, the rectifying unit 22 is provided in a relatively upstream portion of the water jacket 20.

  The rectification unit 22 is provided in each cylinder except for the first cylinder # 1 located on the most end side in the cylinder row direction. In this case, one rectifier 22 is provided around each of the second, third, and fourth cylinders # 2, # 3, and # 4.

  Moreover, the rectification | straightening part 22 is provided in the position corresponding to the center of the cylinder bore 11a in a cylinder row direction. In other words, the rectifying unit 22 is provided at a position relatively far from the head bolt hole 17, more specifically, at a position intermediate between the head bolt holes 17 and 17 adjacent to each other in the cylinder row direction.

  Further, the depth D of the water jacket 20 in each of the three rectifying units 22, 22,. Specifically, the depth D of the water jacket 20 is equal to the depth D2 (FIG. 4) of the rectifying unit 22 around the second cylinder # 2 → the depth of the rectifying unit 22 around the third cylinder # 3. It becomes shallower in the order of D3 (FIG. 5) → depth D4 (FIG. 6) of the rectifying unit 22 around the fourth cylinder # 4 (D2 <D3 <D4). As described above, the depth D of the water jacket 20 in the rectifying unit 22 is gradually shallower from the upstream side to the downstream side in the flow direction of the cooling water of the water jacket 20.

  The rectifying unit 22 is manufactured as follows in the manufacturing process of the cylinder block 10. When manufacturing the cylinder block 10 by casting, the water jacket 20 is manufactured by a molding die. In this case, since the mold of the water jacket 20 is pulled upward (upward in FIG. 2 and the like) along the cylinder axis direction, a cut of the same shape as the rectifying unit 22 is formed in the lower part of the mold before casting. A notch may be formed in advance. In this way, at the time of casting, the water jacket 20 is formed at the same time as the mold is removed, and at the same time, the rectifying unit 22 is formed. And the rectification | straightening part 22 manufactured in this way is used in the state (state of a rough material) as it is.

  According to this embodiment, since the rectifying unit 22 as described above is provided in the water jacket 20, the following operational effects can be obtained in the cylinder block 10.

  In the exhaust side portion of the water jacket 20 where the rectifying unit 22 is provided, the cooling water introduced from the cooling water inlet 16 is guided by the rectifying unit 22 and goes upward in the cylinder axial direction as indicated by an arrow in FIG. A flow of cooling water is formed. Moreover, since the flow path area of the cooling water is reduced by the rectifying unit 22, the flow rate of the cooling water increases by passing through the rectifying unit 22. Thereby, the upper part of the cylinder barrel 11 (outer wall of the cylinder bore 11a) close to the combustion chamber can be effectively cooled.

  And since the depth D of the water jacket 20 in the rectification | straightening part 22 becomes so shallow that it goes downstream from the upstream of the flow direction of a cooling water, the flow of the cooling water which goes upwards in a cylinder axial direction is suppressed, suppressing a pressure loss. It can be secured. That is, if the depth along the cylinder axis direction of the rectifying unit 22 provided on the upstream side in the flow direction of the cooling water is made too shallow, the flow resistance increases and the pressure loss increases. Will fall. In this embodiment, since the flow area of the cooling water is gradually reduced from the upstream side to the downstream side in the flow direction of the cooling water, an increase in pressure loss can be avoided and a desired flow rate can be secured on the downstream side. It becomes. In this case, the cooling water whose flow velocity at the upper part of the water jacket 20 is accelerated by the rectifying unit 22 flows while maintaining the flow rate also in the intake side portion of the water jacket 20 where the rectifying unit 22 is not provided. For this reason, in this embodiment, the rectifying unit 22 is not provided in a relatively downstream portion of the water jacket 20 (in this embodiment, a portion on the intake side).

  Furthermore, since the rectification unit 22 is formed without any special machining, the rectification unit 22 can be easily manufactured as compared with the conventional example in which the rectification unit is configured by a separate member (rectification member). The manufacturing cost of the cylinder block 10 can be reduced. In addition, in the case of the conventional example, there is a possibility that the position of another member constituting the rectification unit with respect to the cylinder barrel 11 may fluctuate, and there is a concern that the flow of cooling water changes and the desired cooling performance cannot be obtained. Is done. On the other hand, in this embodiment, since the rectification part 22 is integrally formed with the cylinder block 10, the position of the rectification part 22 with respect to the cylinder barrel 11 does not fluctuate at all. Therefore, the stable rectification effect | action by the rectification | straightening part 22 is obtained, and the cylinder block 10 with high reliability is obtained.

  Moreover, since the rectification | straightening part 22 is provided in the location comparatively distant from the head bolt hole 17, it can suppress the deformation | transformation of the cylinder bore 11a by the fastening axial force of a head bolt at the time of a cylinder head assembly | attachment. Specifically, the tightening axial force of the head bolt is transmitted to the cylinder barrel 11 serving as the outer wall of the cylinder bore 11 a through the bottom of the water jacket 20. In this case, as the depth D of the water jacket 20 is shallower, the tightening axial force of the head bolt is more easily transmitted to the cylinder barrel 11, and the deformation amount of the cylinder bore 11a is increased. In this embodiment, the rectification unit 22 is provided at an intermediate position between the head bolt holes 17 and 17 adjacent in the cylinder row direction so that the rectification unit 22 is separated from the head bolt holes 17 and 17. Thereby, since the tightening axial force of the head bolt transmitted to the cylinder barrel 11 via the rectifying unit 22 is suppressed, the deformation of the cylinder bore 11a due to the shallowing of the water jacket 20 can be suppressed.

-Other embodiments-
The embodiment of the present invention has been described above. However, the embodiment shown here is an example and can be variously modified.

  By making the guide surface 22a on the upstream side in the flow direction of the cooling water of the rectifying unit 22 into the following shape, the rectifying action by the rectifying unit 22 can be improved. That is, it is preferable that the guide surface 22a of the rectifying unit 22 has a shape that is inclined to the downstream side in the flow direction of the coolant as it goes upward in the cylinder axial direction, as shown in FIG. Specifically, the rectifying unit 22 shown in FIG. 7 has a shape that tapers toward the upper side in the cylinder axis direction, and the guide surface 22a is not parallel to the cylinder axis direction and is oblique to the cylinder axis direction. Leaning on. In this case, the inclination angle of the guide surface 22a may be set to the same angle with respect to the plurality of rectifying units 22, 22,.

  By providing such a guide surface 22a, the cooling water is easily guided upward in the cylinder axial direction, so that the rectifying action by the rectifying unit 22 can be improved. Thereby, the upper part of the cylinder barrel 11 close to the combustion chamber can be cooled more effectively. In order to manufacture the rectifying unit 22 having the guide surface 22a as described above, when the notch corresponding to the rectifying unit 22 is formed in the lower part of the mold of the water jacket 20, an inclined surface having the same inclination as the guide surface 22a is previously formed. It should be provided.

  It is good also as a structure which provides the rectification | straightening part 22 also in the part by the side of the intake air used as the comparatively downstream of the water jacket 20. FIG. In the above embodiment, the flow rate of the cooling water in the upper part of the water jacket 20 is maintained in the intake side portion of the water jacket 20, and the rectifying unit 22 is not provided in the intake side portion. However, from the viewpoint of preventing a decrease in the flow rate of the cooling water in the upper portion of the water jacket 20 in the intake side portion of the water jacket 20, it is preferable to provide the rectifying unit 22 also in the intake side portion of the water jacket 20. . In this case, the intake-side rectification unit 22 is formed so that the depth of the water jacket 20 is the same as or shallower than the exhaust-side rectification unit 22 of the fourth cylinder # 4 of the above embodiment. Is possible. Further, the intake side rectification unit 22 can be provided in each cylinder.

  The flow of the cooling water in the water jacket 20 mentioned in the above embodiment and the position of the cooling water inlet 16 are examples, and may be other than that. For example, the flow of the cooling water in the water jacket 20 may be configured such that the cooling water flows in the order of the intake side portion → the exhaust side portion. In this case, it is preferable to provide the rectifying unit 22 at a portion on the intake side that is relatively upstream of the water jacket 20. Moreover, the flow of the cooling water in the water jacket 20 may be such that the cooling water introduced from one end side in the cylinder row direction flows separately into an intake side portion and an exhaust side portion of the water jacket. . In this case, it is preferable to provide the rectification unit 22 at the intake side portion and the exhaust side portion of the water jacket 20.

  The in-line four-cylinder gasoline engine for automobiles mentioned in the above embodiment is an example, and the present invention can be applied to other multi-cylinder internal combustion engines. For example, the present invention is applicable not only to automobiles but also to engines used for other purposes. The present invention can also be applied to a diesel engine. Further, the number of cylinders and the engine type (separate type such as in-line type, V type, and horizontally opposed type) are not particularly limited. Furthermore, the present invention can be applied to a cylinder block that does not have a siamese structure. The present invention is also applicable to a closed deck structure cylinder block.

It is a top view which shows the cylinder block which concerns on embodiment. It is a figure which shows the inside of the cylinder block seen from the X2 direction in FIG. It is sectional drawing along the X3-X3 line | wire in FIG. It is sectional drawing along the X4-X4 line | wire in FIG. It is sectional drawing along the X5-X5 line | wire in FIG. It is sectional drawing along the X6-X6 line | wire in FIG. In other embodiment, it is a figure corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Cylinder barrel 11a Cylinder bore 16 Cooling water inlet 17 Head bolt hole 20 Water jacket 22 Rectification part

Claims (5)

A cooling water passage formed so as to surround the cylinder bore of the multi-cylinder internal combustion engine;
In the cylinder block of the internal combustion engine configured to introduce cooling water from one end side in the cylinder row direction into the cooling water passage,
The cooling water passage is provided with a plurality of protrusions for forming a flow of cooling water directed upward in the cylinder axial direction,
The protrusions are provided only on the exhaust side of the cooling water passage and on the exhaust side of the cooling water passage, and are provided on each cylinder except for the cylinder arranged at the most end side in the cylinder row direction. And
In the portion of the cooling water passage where the protrusions are provided, the depth along the cylinder axis direction of the cooling water passage is shallower than the portion where the protrusions are not provided, and the depth is the cooling water. It becomes shallower from the upstream side to the downstream side in the flow direction of
The cylinder block of the internal combustion engine, wherein the protrusions are integrally formed on the outer wall of the cylinder bore at the same time as the cylinder block is cast . The cylinder block of the internal combustion engine according to claim 1,
The cylinder block of an internal combustion engine, wherein the cooling water introduced into the cooling water passage flows through an exhaust side portion of the cooling water passage and then flows through an intake side portion of the cooling water passage . In the cylinder block of the internal combustion engine according to claim 1 or 2,
Each of the protrusions extends from the bottom of the cooling water passage toward the top surface . In the cylinder block of the internal combustion engine according to any one of claims 1 to 3 ,
Each said protrusion is formed in the intermediate position of the head bolt holes mutually adjacent in a cylinder row direction, The cylinder block of the internal combustion engine characterized by the above-mentioned. In the cylinder block of the internal combustion engine according to any one of claims 1 to 4 ,
The cylinder block of the internal combustion engine, wherein the guide surface on the upstream side in the flow direction of the cooling water of each of the protrusions is formed so as to be inclined toward the downstream side in the flow direction as it goes upward.

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