JP2011231704A - Cylinder block for multi-cylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress or prevent the supercooling of the lower region of cylinder bores 2 in a cylinder block 1 for a multi-cylinder internal combustion engine in which a water jacket 4 is so disposed as to surround a large number of cylinder bores 2, and an introducing path 6 for coolant is connected to the bottom of a wide section 4a arranged at one end of in a cylinder array directionin the water jacket 4.SOLUTION: In a connection part between the introducing path 6 and the water jacket 4, a coolant guide means (7) is arranged for the purpose of keeping away coolant introduced from the introducing path 6 from the lower region of a cylinder bore side internal wall surface 4b (which is also called an outer wall surface of a cylinder barrel 3) of the water jacket 4 and directing the coolant to the upper region.

Description

  The present invention relates to a cylinder block of a multi-cylinder internal combustion engine. In particular, the present invention relates to a technique for controlling the flow of coolant at a coolant introduction portion of a water jacket provided in a cylinder block.

  For example, as shown in Patent Document 1, a cylinder block of a multi-cylinder internal combustion engine is provided with a water jacket for cooling a cylinder bore heated by heat from a combustion chamber. The water jacket is provided so as to surround a wall portion (cylinder barrel) that forms the cylinder bore. The water jacket is introduced with a coolant fed by a water pump installed in the internal combustion engine. The cooling liquid is, for example, an antifreeze liquid called LLC (Long Life Coolant) as generally known.

  Generally, in an internal combustion engine, a region close to the combustion chamber in the cylinder bore has the highest temperature because the combustion chamber has the highest temperature. Therefore, in order to actively cool the upper area of the cylinder bore, that is, the area close to the combustion chamber, the flow of the cooling liquid is set so that the cooling liquid introduced into the water jacket flows obliquely upward. In the water jacket, the coolant flows in a direction crossing the cylinder bore, that is, in a direction orthogonal to the central axis direction of the cylinder bore.

  Incidentally, the coolant introduction path may be connected to the lower side of the front end of the internal combustion engine, for example, in a water jacket. This is related to the installation location of the water pump for sending out the coolant. In general, the water pump is often attached to the lower side of the front end of the internal combustion engine.

Japanese Patent No. 2002-276361

  In the place where the coolant introduction path is connected to the water jacket as in the above-described conventional example, when the coolant is introduced into the water jacket from the introduction path, the coolant is connected to the cylinder bore side inner wall surface of the water jacket (the cylinder barrel). Colliding with the lower region of the outer wall (also referred to as outer wall surface), it tends to flow obliquely upward while being diffused.

  In such a case, among the many cylinder bores, the lower region tends to be excessively cooled with respect to the cylinder bore located closer to the introduction path. Therefore, temperature variation occurs in the upper and lower regions of the cylinder bore, and the variation in clearance between the upper and lower regions of the cylinder bore and the piston increases. For this reason, there is a concern that uneven wear of the cylinder bore or piston may occur, or that friction loss increases and fuel consumption of the internal combustion engine decreases.

  By the way, in order to actively cool the upper region (combustion chamber region) of the cylinder bore, for example, an insert member called a spacer may be inserted into a water jacket. In such a case, the coolant introduced from the introduction passage may flow between the lower region of the inner wall surface of the cylinder bore side of the water jacket and the insert member. The side area tends to be overcooled.

  In view of such circumstances, in the present invention, a water jacket is provided so as to surround a large number of cylinder bores, and a coolant introduction path is connected to the bottom of the wide portion provided on one end side in the cylinder bore arrangement direction in the water jacket. An object of the present invention is to suppress or prevent overcooling of a lower region of a cylinder bore in a cylinder block of a multi-cylinder internal combustion engine.

  The present invention provides a multi-cylinder internal combustion engine in which a water jacket is provided so as to surround a large number of cylinder bores, and a coolant introduction path is connected to the bottom of a wide portion provided on one end side in the cylinder bore arrangement direction in the water jacket. A cylinder block for connecting the coolant introduced from the introduction path to the upper area of the water jacket away from the lower area of the inner wall surface on the cylinder bore side in the connection portion of the introduction path to the water jacket The cooling liquid guide means is provided.

  In this configuration, when the coolant is introduced into the water jacket from the introduction path, the coolant does not easily collide with the lower region of the cylinder bore side inner wall surface (also referred to as the outer wall surface of the cylinder barrel) in the wide portion of the water jacket. As a result, the water jacket will flow obliquely upward.

  As a result, among the many cylinder bores, particularly on the cylinder bore closer to the introduction path, the lower region (crankshaft closer region) that is relatively difficult to raise the temperature on the cylinder bore side inner wall surface of the water jacket is less likely to be excessively cooled. The upper region where the temperature rises most easily (combustion chamber region) is cooled efficiently.

  Thus, according to the said structure, it becomes possible to cool an upper area | region efficiently, suppressing or preventing the overcooling of a lower area | region in the cylinder bore side inner wall surface of a water jacket.

  As a result, temperature variations in the upper and lower regions of the cylinder bore can be reduced, and therefore, variations in clearance between the upper and lower regions of the cylinder bore and the piston can be reduced. As a result, uneven wear of the cylinder bore and piston can be suppressed or prevented, and friction loss can be reduced, which is advantageous in improving the fuel efficiency of the internal combustion engine.

  Preferably, the width of the introduction path is set smaller than the bottom width of the wide portion, and the introduction path is connected to the bottom of the wide portion of the water jacket in a state of being offset toward the cylinder bore side. In the introduction path, the inner wall surface on the cylinder bore side is offset from the cylinder bore side inner wall surface of the water jacket, and the corner portion of the part where the cylinder bore side inner wall surface of the introduction path intersects the bottom wall surface of the water jacket is formed. The coolant guide means is configured by setting the radius of curvature to be smaller than the offset dimension while making the shape round.

  Here, the connection portion of the introduction path with respect to the water jacket and the configuration of the coolant guide means are specified. According to this specification, immediately after the coolant is introduced into the water jacket from the introduction path, the coolant is less likely to collide with the lower region of the inner wall surface of the cylinder bore in the wide portion of the water jacket, and the water jacket is inclined upward. It becomes clear that it will be in a form that is washed away.

  Preferably, the width of the introduction path is set smaller than the bottom width of the wide portion, and the introduction path is connected to the bottom of the wide portion of the water jacket in a state of being offset toward the cylinder bore side. In the introduction path, the inner wall surface on the cylinder bore side is offset from the cylinder bore side inner wall surface of the water jacket, and the corner portion of the part where the cylinder bore side inner wall surface of the introduction path intersects the bottom wall surface of the water jacket is formed. The coolant guide means is configured by forming a convex shape protruding upward.

  Here, the connection portion of the introduction path with respect to the water jacket and the configuration of the coolant guide means are specified. According to this specification, immediately after the coolant is introduced into the water jacket from the introduction path, the coolant is less likely to collide with the lower region of the inner wall surface of the cylinder bore in the wide portion of the water jacket, and the water jacket is inclined upward. It becomes clear that it will be in a form that is washed away.

  Preferably, the insert member is inserted into the water jacket in a state of being brought close to the inner wall surface so as to cover a region excluding the region close to the combustion chamber on the cylinder bore side inner wall surface.

  In this configuration, the insert member makes it easier for the coolant introduced into the water jacket from the introduction path to collide with the upper region on the cylinder bore side inner wall surface, and less likely to collide with the lower region from the intermediate region on the cylinder bore side inner wall surface. is doing. This makes it possible to efficiently cool the upper region where the temperature rises most easily in the cylinder bore and makes it difficult to excessively cool the lower region where the temperature rise is relatively difficult.

  Preferably, a corner of the portion where the inner wall surface on the back side located in the back of the cylinder bore arrangement direction in the introduction path intersects the bottom wall surface of the water jacket is rounded, and the radius of curvature of the round is the offset Set smaller than the dimension.

  In this configuration, the rising angle when the coolant introduced into the water jacket from the introduction path flows obliquely upward is as large as possible.

  The present invention provides a multi-cylinder internal combustion engine in which a water jacket is provided so as to surround a large number of cylinder bores, and a coolant introduction path is connected to the bottom of a wide portion provided on one end side in the cylinder bore arrangement direction in the water jacket. In the cylinder block, the way in which the coolant flows in the coolant introduction portion of the water jacket is devised, so that it is possible to suppress or prevent the lower region of the cylinder bore from being overcooled.

1 is a perspective view showing an embodiment of a cylinder block of a multi-cylinder internal combustion engine according to the present invention. It is a side view which shows typically the arrangement | positioning relationship between the water pump and water jacket of the cylinder block of FIG. It is a top view of the cylinder block of FIG. FIG. 4 is a cross sectional view taken along line (4)-(4) in FIG. 3. FIG. 5 is a perspective view of only the water jacket shown in FIGS. 1 to 4. It is the figure which looked at the introduction path from the direction of arrow (6) in FIG. It is the figure which looked at the introduction path from the direction of arrow (7) in FIG. FIG. 5 is a view corresponding to FIG. 4 in another embodiment of the cylinder block of the multi-cylinder internal combustion engine according to the present invention. FIG. 5 is a view corresponding to FIG. 4 in another embodiment of the cylinder block of the multi-cylinder internal combustion engine according to the present invention. FIG. 9 is a view corresponding to FIG. 8 in another embodiment of the cylinder block of the multi-cylinder internal combustion engine according to the present invention. It is a comparative example of this invention, and is a figure corresponding to FIG.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  1 to 7 show an embodiment of the present invention. In this embodiment, a water-cooled in-line four-cylinder internal combustion engine (engine) is taken as an example. The cylinder block 1 shown in the figure has a structure without a cylinder liner.

  The cylinder block 1 shown in this embodiment is provided with four cylinder bores 2 in a row in the longitudinal direction. Although not shown, each cylinder bore 2 is inserted with a piston. The cylindrical wall that forms each cylinder bore 2 is called a cylinder barrel 3. The cylinder barrel 3 is a siamese type. The siamese type cylinder barrel 3 has a shape in which cylindrical wall portions forming the cylinder bores 2 are connected in series.

  The cylinder block 1 is provided with a water jacket 4. The water jacket 4 is provided so as to surround the cylinder barrel 3. As a result, the outer wall surface of the cylinder barrel 3 is the same as the inner wall surface 4 b on the cylinder bore 2 side in the water jacket 4.

  Next, the water jacket 4 will be described in detail. As shown in FIGS. 1 and 3, the water jacket 4 is opened toward a deck surface, that is, a surface on which a cylinder head (not shown) is assembled. The cylinder block 1 provided with such a water jacket 4 is called a so-called open deck type.

  The width of the water jacket 4, that is, the width along the radial direction of the cylinder bore 2 is gradually increased from the lower side to the upper side of the cylinder bore 2 as shown in FIG. 4 in this embodiment. This widening is the draft of the mold used when the cylinder block 1 is cast.

  On the bottom wall surface 4c of the water jacket 4, on one end side in the cylinder bore arrangement direction (front end side of the cylinder block 1), as shown in FIGS. 2 and 3, a wide portion having a larger width along the radial direction of the cylinder bore 2 4a is provided, and a coolant introduction path 6 is connected to the bottom of the wide portion 4a.

  Into the introduction path 6 is introduced the coolant sent from the water pump 5 for circulating the coolant of the internal combustion engine. In this embodiment, the introduction path 6 is provided on the exhaust system installation side in the cylinder block 1.

  As shown in FIGS. 4 and 5, the width of the introduction path 6 is set smaller than the bottom width of the wide portion 4 a of the water jacket 4. As shown in FIGS. 4 and 5, the introduction path 6 is connected to the bottom wall surface 4 c of the wide portion 4 a of the water jacket 4 in a state of being offset toward the non-cylinder bore side (outside). , The inner wall surface 6a on the cylinder bore 2 side is offset from the cylinder bore side inner wall surface 4b of the water jacket 4. This offset amount is indicated by W in FIG. Furthermore, as shown in FIG. 3, when viewed from above, the introduction path 6 is connected to the upstream corrugated passage portion 4d of the two long corrugated passage portions 4d and 4e of the water jacket 4 in a straight line. As a result, the coolant is introduced straight from the introduction path 6 into the long upstream corrugated passage portion 4d of the water jacket 4 when viewed from above.

  The coolant introduced from the introduction path 6 is guided to the upper area of the wide portion 4a of the water jacket 4 away from the lower area of the cylinder bore side inner wall surface 4b at the connecting portion of the introduction path 6 to the water jacket 4. The coolant guiding means is provided.

  For example, as shown in FIGS. 4 and 7, the coolant guide means has a round shape at the side corner 7 where the cylinder bore side inner wall surface 6 a of the introduction path 6 intersects the bottom wall surface 4 c of the water jacket 4. In addition, the radius of curvature R1 of the roundness is set smaller than the offset dimension W.

  Further, for example, as shown in FIG. 6, the coolant guiding means is a corner on the back side of a portion where the back inner wall surface 6 b located in the back of the cylinder bore arrangement direction in the introduction path 6 and the bottom wall surface 4 c of the water jacket 4 intersect. 8 is formed into a round shape, and the radius of curvature R2 of the roundness is set smaller than the offset dimension W.

  Next, the flow of the coolant introduced from the introduction path 6 to the water jacket 4 in this embodiment will be described.

  When the coolant is introduced into the water jacket 4 from the introduction path 6, the outer circumference of the cylinder barrel 3 is unidirectionally traversed by the cylinder bores 2 in the water jacket 4 as indicated by the arrows in FIGS. Will flow into.

  By the way, as shown in FIG. 3, the introduction direction of the coolant from the introduction path 6 to the water jacket 4 is a straight line when the introduction path 6 and the long upstream corrugated passage portion 4 d of the water jacket 4 are viewed from above. Therefore, the coolant introduced into the water jacket 4 from the introduction path 6 flows straight toward the longitudinal one end of the long upstream corrugated passage portion 4d of the water jacket 4, and 2, when viewed from the side, the coolant introduced into the water jacket 4 from the introduction path 6 is below the front end side of the wide portion 4a of the water jacket 4, that is, the long upstream corrugated passage portion 4d. It begins to flow diagonally upward from the side.

  In addition, as described above, the coolant guide means (7, 8) is provided at the connecting portion between the introduction path 6 and the water jacket 4, so that the wide portion of the water jacket 4 extends from the introduction path 6. Immediately after the coolant is introduced into 4a, the coolant is less likely to collide from the lower side of the cylinder bore side inner wall surface 4b of the water jacket 4 to the middle region, and flows in a form that rapidly rises obliquely upward in the water jacket 4. It comes to be.

  As a result, among the large number of cylinder bores 2, particularly the cylinder bore 2 near the front end, that is, near the introduction path 6, the lower region (crankshaft region) of the water jacket 4 on the cylinder bore side inner wall surface 4 b becomes difficult to be excessively cooled. The upper region (combustion chamber region) is efficiently cooled.

  Incidentally, the applicant of the present application aims to improve the cooling performance of the entire upper and lower sides of the cylinder bore 2 in the development process of the present invention, and immediately after being introduced into the water jacket 4 from the introduction path 6, the coolant is supplied to the cylinder bore of the water jacket 4. It was thought that it would be possible to flow from bottom to top along the side inner wall surface 4b.

  Therefore, specifically, as shown in FIG. 11, for example, the introduction path 6 and the water jacket 4 are connected as smoothly as possible. More specifically, the side corner portion 7 where the cylinder bore side inner wall surface 6a of the introduction path 6 and the bottom wall surface 4c of the water jacket 4 intersect has a round shape, and the curvature radius R3 of this roundness is set to the offset dimension W. A larger value is set. This configuration is a comparative example of this embodiment.

  According to this comparative example, as described above, immediately after being introduced into the water jacket 4 from the introduction path 6, the coolant is moved from the bottom to the top along the cylinder bore side inner wall surface 4 b in the wide portion 4 a of the water jacket 4. It becomes possible to flow. However, in this comparative example, since the coolant introduced into the wide portion 4a of the water jacket 4 immediately collides with the lower region of the cylinder bore side inner wall surface 4b, the lower region of the cylinder bore 2 is excessively cooled. As a result, temperature variations in the upper and lower regions of the cylinder bore 2 become large. Based on this knowledge, the above-described embodiment has been proposed.

  As described above, in the embodiment to which the present invention is applied, the way in which the coolant flows in the coolant introduction portion of the water jacket 4 is devised. Therefore, among the many cylinder bores 2, the cylinder bores particularly close to the introduction path 6. 2, it is possible to efficiently cool the upper region where temperature rises most easily while suppressing or preventing overcooling of the lower region, which is relatively difficult to raise temperature.

  As a result, temperature variations in the upper and lower regions of the cylinder bore 2 can be reduced, so that variations in clearance between the upper and lower regions of the cylinder bore 2 and the piston can be reduced. As a result, uneven wear of the cylinder bore 2 and piston can be suppressed or prevented, and friction loss can be reduced, which is advantageous in improving the fuel efficiency of the internal combustion engine.

  In addition, this invention is not limited only to the said embodiment, All the deformation | transformation and application included in the range equivalent to the claim and the said range are possible. Examples are given below.

  (1) Another embodiment of the present invention is shown in FIG. In this embodiment, as the coolant guiding means when introducing the coolant from the introduction path 6 to the water jacket 4, the side of the portion where the cylinder bore side inner wall surface 6 a of the introduction path 6 intersects the bottom wall surface 4 c of the water jacket 4. The side corner portion 7 has a convex shape protruding upward, and the other configuration is the same as that of the above-described embodiment.

  In this embodiment, immediately after the coolant is introduced from the introduction path 6 to the wide portion 4a of the water jacket 4, the coolant is less likely to collide with the lower region of the cylinder bore side inner wall surface 4b of the water jacket 4. The jacket 4 is swept upward and obliquely upward. Thereby, also in this embodiment, the same effect as the above-described embodiment can be obtained.

  (2) In each embodiment described above, it is possible to insert an insert member 9 called a spacer into the water jacket 4.

  For example, FIG. 9 shows a state where the insert member 9 is inserted into the water jacket 4 of the embodiment shown in FIG. Moreover, the state which inserted the insert member 9 in the water jacket 4 of embodiment shown in FIG. 8 is shown in FIG. Here, the insert member 9 is a ring-shaped sheet that is disposed on the entire circumference of the water jacket 4.

  In both the embodiment shown in FIG. 9 and FIG. 10, the insert member 9 is inserted in a state where it is brought close to the inner wall surface 4b so as to cover the lower region from the intermediate region of the cylinder bore side inner wall surface 4b. In other words, the insert member 9 is disposed so as to be exposed without covering the cylinder bore side inner wall surface 4b, that is, the region near the combustion chamber.

  In this configuration, the insert member 9 makes it easy for the coolant to collide with the upper region of the cylinder bore side inner wall surface 4b of the water jacket 4, and makes it difficult for the coolant to collide with the lower region from the intermediate region. This makes it possible to efficiently cool the upper region where the temperature rises most easily in the cylinder bore 2 and makes it difficult to excessively cool the lower region where the temperature rise is relatively difficult.

  (3) In each of the above embodiments, the back side corner portion 8 has a round shape and the curvature radius R2 of the roundness is set smaller than the offset dimension W. However, the present invention is limited to this. For example, the radius of curvature R2 of the rounded corner 8 may be set larger than the offset dimension W, and such a case is also included in the present invention.

  In this case, as soon as the cooling liquid is introduced from the introduction path 6 into the wide portion 4a of the water jacket 4, the cooling liquid flows in the water jacket 4 so as to rise gently and obliquely upward. This also makes it possible to efficiently cool the upper region where the temperature rises most easily in the cylinder bore 2 and excessively cool the lower region where the temperature rises relatively less in the cylinder bore 2 as described above. It is still possible to obtain the effect that “it can be made difficult”.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder bore 3 Cylinder barrel 4 Water jacket 4a Wide part of water jacket 4b Cylinder bore side wall surface of water jacket 4c Bottom wall surface of water jacket 5 Water pump 6 Introduction path 6a Cylinder bore side wall surface 6b of introduction path Side wall 7 Side corner 8 Back corner

Claims (5)

This is a cylinder block of a multi-cylinder internal combustion engine in which a water jacket is provided so as to surround a large number of cylinder bores, and a coolant introduction path is connected to the bottom of a wide portion provided on one end side in the cylinder bore arrangement direction in the water jacket. And
Cooling liquid guide means for guiding the cooling liquid introduced from the introduction path to the upper area away from the lower area of the inner wall surface on the cylinder bore side in the water jacket is provided at a connection portion of the introduction path with respect to the water jacket. A cylinder block of a multi-cylinder internal combustion engine, which is provided. In the cylinder block according to claim 1,
The width of the introduction path is set smaller than the bottom width of the wide portion,
The introduction path is connected to the bottom of the wide portion of the water jacket in a state of being offset toward the cylinder bore side, so that the inner wall surface on the cylinder bore side is outside the inner wall surface on the cylinder bore side of the water jacket in the introduction path. Offset
The corner of the portion where the cylinder bore side inner wall surface of the introduction path and the bottom wall surface of the water jacket intersect is rounded, and the radius of curvature of the roundness is set to be smaller than the offset dimension, whereby the coolant guide A cylinder block, characterized in that the means is configured. In the cylinder block according to claim 1,
The width of the introduction path is set smaller than the bottom width of the wide portion,
The introduction path is connected to the bottom of the wide portion of the water jacket in a state of being offset toward the cylinder bore side, so that the inner wall surface on the cylinder bore side is outside the inner wall surface on the cylinder bore side of the water jacket in the introduction path. Offset
The cooling liquid guiding means is configured by forming a convex shape protruding upward at a corner of a portion where the inner wall surface on the cylinder bore side of the introduction path and the bottom wall surface of the water jacket intersect. Cylinder block. In the cylinder block according to any one of claims 1 to 3,
A cylinder block, wherein an insert member is inserted into the water jacket so as to be close to the inner wall surface so as to cover a region excluding the region close to the combustion chamber on the inner wall surface on the cylinder bore side. In the cylinder block according to any one of claims 1 to 4,
The corner of the portion where the inner wall surface on the back side located in the cylinder bore arrangement direction in the introduction path intersects the bottom wall surface of the water jacket has a round shape, and the radius of curvature of the roundness is smaller than the offset dimension. A cylinder block characterized by being set.

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