JP2009257107A - Cylinder block cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block cooling structure capable of preventing the deterioration in circularity of a cylinder bore lower part when actually operating an engine, by restraining bore deformation caused when actually operating the engine, without increasing a process when processing a cylinder block. <P>SOLUTION: By forming a spacer 17 arranged in a bottom part of a water jacket 6 so as to check a flow of cooling water in the bottom part in the water jacket 6 of a phase corresponding to a bolt fastening part 10 by a head bolt 11, a cooling quantity of a cylinder bore 4 in a phase corresponding to the bolt fastening part 10 by the head bolt 11, is relatively reduced more than a cooling quantity of the cylinder bore 4 in a phase corresponding to a part except for the bolt fastening part 10 by the head bolt 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling structure for a cylinder block constituting an internal combustion engine such as an automobile engine, and more particularly to a cooling technique using a water jacket formed in the cylinder block.

  For example, in a cylinder block that constitutes an internal combustion engine such as an automobile engine, as a general configuration, a cylinder bore that is a cylindrical hole portion in which a piston is slidably housed, and a surface on which the cylinder bore opens and a cylinder And a cylinder head mounting surface (hereinafter simply referred to as “head mounting surface”) on which the head is assembled. When the cylinder head is assembled to the head mounting surface, a fastener (head bolt) such as a bolt is used. That is, the cylinder head is fastened and fixed to the cylinder block by screwing the head bolt into the head bolt hole that penetrates the cylinder head and becomes an internal thread portion provided in the cylinder block.

  A head bolt hole into which the head bolt is screwed when the cylinder head is fixed to the cylinder block is provided around the cylinder bore on the head mounting surface. Specifically, there is a configuration in which four are provided at substantially equal intervals around the cylinder bore. That is, in this case, for example, in an in-line four-cylinder engine mounted on an automobile or the like, two head bolt holes are shared between adjacent cylinder bores for four cylinder bores arranged in a line. A total of 10 head bolt holes will be provided (see FIG. 1).

In such a configuration, deformation of the cylinder bore (bore deformation) occurs when the cylinder head is assembled to the cylinder block and when the engine configured by using the cylinder block is operated, and the roundness of the cylinder bore is deteriorated. Is a problem.
These bore deformations will be specifically described with reference to FIG. FIG. 11 is a schematic diagram showing the arrangement of the bolt fastening portion with respect to the cylinder bore and the bore deformation in the vicinity of the female thread depth of the conventional head bolt hole, and (a) is a diagram showing a single product state (non-assembled state). b) is a diagram showing bore deformation during assembly, and (c) is a diagram showing bore deformation during engine operation.

  As shown in FIG. 11, as an example of arrangement of the bolt fastening portion for fixing the cylinder head to the cylinder block with respect to the cylinder bore, four bolt fastening portions 110 are provided at substantially equal intervals around the cylinder bore 104 with respect to one cylinder bore 104. There is a configuration that can be. In each bolt fastening part 110, the head bolt 111 is screwed into the head bolt hole 112 formed in the cylinder block.

  The single product state shown in FIG. 11A is a state where the cylinder head is not yet fixed by tightening the head bolt 111 screwed into the head bolt hole 112. That is, since the tightening force (fastening force) by the head bolt 111 is not applied to the cylinder block, the cylinder block 104 does not deform due to the tightening force acting, and the cylinder bore 104 does not deform. It becomes a state.

  At the time of assembly shown in FIG. 11B, the cylinder head is fastened and fixed to the cylinder block by tightening the head bolt 111. At this time, the tightening force (arrow F in FIG. 11B) by the head bolt 111 acts on the cylinder block, and this tightening force F causes the cylinder block to be deformed, resulting in bore deformation. The bore deformation (hereinafter referred to as “assembly deformation”) that occurs when the cylinder head is assembled is caused by strongly pressing the upper surface of the bore (the peripheral edge of the cylinder bore 104 on the head mounting surface) by tightening the head bolt 111.

  Therefore, the deformation is increased around the bolt that is particularly strongly pressed, and in the configuration in which the bolt fastening portions 110 are provided at approximately four intervals around the cylinder bore 104 as in this example, the bolt fastening is performed at the cylinder bore 104. Deformation in which a phase corresponding to the portion 110 (hereinafter referred to as “volt phase”) squeezes inward, in other words, deformation that bulges inward relatively occurs. As a result, as shown in FIG. 11B, the assembly deformation is such that the cylinder bore 104 that is circular in plan view becomes a particularly cruciform shape in the vicinity of the female screw depth of the head bolt hole 112 ( So-called fourth order deformation).

  Further, in the actual operation of the engine configured by using the cylinder block in which the cylinder head is assembled by the head bolt 111 as described above, in addition to the above-described assembly deformation, the engine thermal expansion, thermal distortion, etc. There is bore deformation (hereinafter referred to as “thermal deformation”) caused by a thermal load (thermal stress).

  As shown in FIG. 11C, when the engine is actually operating, the temperature of the cylinder block rises, and the cylinder bore expands in the circumferential direction as compared with the assembled shape shown by the dotted line in FIG. In FIG. 11C, the deformation at the bolt phase is indicated by an arrow P0, and the deformation at other than the bolt phase is indicated by an arrow Q0.

  The bore deformation as described above deteriorates the roundness of the cylinder bore. Deterioration of the roundness of the cylinder bore due to thermal deformation during engine operation including assembly deformation causes an increase in friction (sliding resistance) due to sliding of the piston in the cylinder bore. The increase in friction causes the output of the internal combustion engine to be limited and the fuel consumption to deteriorate.

  In other words, when a piston ring that slides against the cylinder bore is attached to the piston, when the roundness of the cylinder bore deteriorates, the portion that deforms from a perfect circle to a large diameter (expanded portion) in the cylinder bore is sealed by the piston ring. The engine oil consumption and blow-by gas increase due to leaching. Such a situation can be avoided by increasing the tension of the piston ring (the force to spread) (increasing the tension) and ensuring a minimum pressing force by the piston ring even at the part where the cylinder bore changes to a large diameter. . However, increasing the tension of the piston ring causes an increase in overall friction in the cylinder bore.

Therefore, as a technique for suppressing the bore deformation that causes the above-described problems, there is a technique described in Patent Document 1, for example.
This document discloses a method of making the thickness of the cylinder block near the head bolt screw hole thinner than other portions. That is, by thinning the vicinity of the head bolt screw hole, the cylinder bore is easily deformed to the phase of the head bolt when the head bolt is fastened, and the effect of preventing the roundness from being deteriorated due to deformation of other portions can be obtained.

Further, as a technique for uniformly adjusting the temperature of the cylinder bore, there is a technique described in Patent Document 2, for example.
This document discloses a method in which a spacer is disposed at the bottom of a water jacket formed in a cylinder block to adjust the flow of cooling water. That is, an effect of reducing the temperature difference from the upper portion where the temperature is likely to rise can be obtained by arranging the spacer in a portion where the temperature is difficult to rise compared to the upper portion, such as the bottom portion of the water jacket.

  However, the technique disclosed in Patent Document 1 requires an additional step of reducing the thickness of the cylinder block when processing the cylinder bore in the cylinder block to obtain a predetermined roundness. An increase in the number of processing steps leads to an increase in cost, which is not preferable for improving mass productivity.

Further, in the technology disclosed in Patent Document 2, a method for reducing the temperature difference in the circumferential direction of the cylinder bore is not described in detail, and the roundness of the cylinder bore is particularly low at the bottom of the water jacket where the bore deformation is large. No specific technique for obtaining the above is disclosed.
Japanese Utility Model Publication No. 5-12646 JP 2002-13440 A

  The present invention has been made in view of the above-described problems of the prior art, and the problem to be solved is that the bore deformation that occurs during engine operation is not accompanied by an increase in the number of processes when machining the cylinder block. An object of the present invention is to provide a cooling structure for a cylinder block that can be suppressed and can prevent deterioration of the roundness of the lower part of the cylinder bore during actual operation of the engine.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, a cylinder head mounting surface to which the cylinder head is fixed by a fastening member, a cylinder bore opened in a cylindrical shape on the cylinder head mounting surface, and a water formed in a groove shape around the cylinder bore A cooling structure of a cylinder block comprising a jacket, wherein a cooling amount of the cylinder bore in a phase corresponding to a fastening portion by the fastening member is in a phase corresponding to a portion other than the fastening portion by the fastening member at a bottom portion of the water jacket. A member that is relatively smaller than the cylinder bore cooling amount is provided in the water jacket.

  In Claim 2, The said member is a spacer arrange | positioned in the phase corresponding to the fastening part by the said fastening member at least inside the bottom part in the said water jacket, This spacer is a fastening part by the said fastening member. Is formed so as to block the flow of cooling water at least inside the bottom of the water jacket.

  In Claim 3, The said member is a spacer arrange | positioned in the phase corresponding to other than the fastening part by the said fastening member on the outer side of the bottom part in the said water jacket, This spacer is a fastening part by the said fastening member. The flow rate of the cooling water at the bottom of the water jacket in a phase corresponding to other than that is formed to be higher than the flow rate of the cooling water at the bottom of the water jacket at a phase corresponding to the fastening portion by the fastening member. It is.

As effects of the present invention, the following effects can be obtained.
That is, according to the present invention, it is possible to suppress the deformation of the bore that occurs during engine operation without increasing the number of processes when processing the cylinder block, and to prevent the roundness of the lower portion of the cylinder bore from deteriorating during engine operation. Thus, it is possible to prevent the output of the internal combustion engine from being limited and the fuel consumption from being deteriorated.

Next, embodiments of the invention will be described.
FIG. 1 is a plan view of the entire cylinder block.
FIG. 2 is a horizontal sectional view of the bottom of the water jacket of the cylinder block according to the first embodiment of the present invention.
3A is a cross-sectional view taken along line A1-A1 in FIG. 2, and FIG. 3B is a cross-sectional view taken along line B1-B1 in FIG.
FIG. 4 is a schematic diagram showing bore deformation according to the first embodiment of the present invention.
FIG. 5 is a horizontal sectional view of the bottom of the water jacket of the cylinder block according to the second embodiment of the present invention.
6A is a cross-sectional view taken along line A2-A2 in FIG. 5, and FIG. 6B is a cross-sectional view taken along line B2-B2 in FIG.
FIG. 7 is a schematic diagram showing bore deformation according to the second embodiment of the present invention.
FIG. 8 is a horizontal sectional view of the bottom of the water jacket of the cylinder block according to the third embodiment of the present invention.
9A is a cross-sectional view taken along line A3-A3 in FIG. 8, and FIG. 9B is a cross-sectional view taken along line B3-B3 in FIG.
FIG. 10 is a schematic diagram showing bore deformation according to the third embodiment of the present invention.
FIG. 11 is a schematic diagram showing the arrangement of bolt fastening portions with respect to the cylinder bore and conventional bore deformation.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[Configuration of cylinder block 1]
First, the overall configuration of the cylinder block 1 to which the cylinder block cooling structure of the present invention is applied will be described with reference to FIGS.
The cylinder block 1 is made of aluminum as a material, and a cylinder head mounting surface (hereinafter referred to as “head mounting surface”) 3 to which the cylinder head 2 is fixed by a head bolt 11 as a fastening member, and the head mounting. A cylinder bore 4 that is opened in a cylindrical shape on the surface 3, and a water jacket 6 that is formed in a groove shape around the cylinder bore 4 via a cylinder portion 5 that is a wall-like portion surrounding the cylinder bore 4.

  The cylinder block 1 constitutes a multi-cylinder engine such as an in-line four-cylinder engine shown in FIG. 1, for example, and includes a plurality of cylinder bores 4 (four in the case of four cylinders), which have a central axis direction. They are arranged in a row so as to be parallel to each other. In the present embodiment, four cylinder bores 4 are arranged in series, but the number thereof may be three or less or five or more, and is not limited to the present embodiment.

  The head mounting surface 3 is a sealing surface formed as a flat surface on one side of the cylinder block 1, and the cylinder head 2 is assembled to the head mounting surface 3 through a gasket or the like. As shown in FIG. 2, when the cylinder head 2 is assembled to the head mounting surface 3, the head bolt 11 is used as the fastening member as described above. That is, the head bolt 11 passes through the cylinder head 2 and is screwed into the head bolt hole 12 serving as a female screw portion provided in the cylinder block 1, whereby the cylinder head 2 is fastened and fixed to the cylinder block 1.

  An oil pan (not shown) is attached to the cylinder block 1 on the side opposite to the head attachment surface 3. Hereinafter, in the cylinder block 1, the side on which the cylinder head 2 is assembled is referred to as “upper”, and the opposite side is referred to as “lower”. As shown in FIG. 1, one of the longitudinal directions in which the cylinder bores 4 are arranged (the upper side shown in FIG. 1) is the front direction, and one of the opposite directions (the lower side shown in FIG. 1) is the rear direction. Furthermore, in this embodiment, the left side toward the front is the thrust direction, and the right side is the anti-thrust direction. However, the thrust / anti-thrust direction may be set opposite to that of the present embodiment.

  A bolt fastening portion 10 as a fastening portion for fixing the cylinder head 2 to the cylinder block 1, that is, a head bolt hole 12 into which the head bolt 11 is screwed, is provided around the cylinder bore 4 on the head mounting surface 3. . In this embodiment, as shown in FIGS. 1 and 2, four cylinders are provided around the cylinder bore 4 at substantially equal intervals. Further, two head bolt holes 12 are shared between adjacent cylinder bores 4. That is, in this case, for example, in a cylinder block constituting an in-line four-cylinder engine, a total of ten head bolt holes 12 are provided for four cylinder bores 4 arranged in a line.

  As shown in FIGS. 3 (a) and 3 (b), a plurality of cylinder bores 4 are arranged as described above with the central axis direction as the vertical direction. A piston ring 8 is attached to the piston 7 housed in the cylinder bore 4. The piston 7 slides back and forth in the cylinder bore 4 through the piston ring 8 in the vertical direction.

  The space above the piston 7 in each cylinder bore 4 constitutes a part of a combustion chamber for burning a fuel / air mixture. The cylinder bore 4 is formed on a cylindrical surface having a predetermined roundness by a finishing process such as a honing process in order to keep the air-fuel mixture and gas generated by combustion confidential. That is, during the actual operation of the engine manufactured using the cylinder block 1, the piston 7 reciprocates and slides due to the explosion / combustion of the air-fuel mixture in the combustion chamber, whereby the piston 7 and the connecting rod (connecting rod) are interposed. The connected crankshaft (output shaft) rotates.

The water jacket 6 is a passage for the cooling water 6 a and is formed so as to surround the plurality of cylinder bores 4 when the cylinder block 1 is cast. The water jacket 6 is provided to the cylinder bore 4 via the cylinder portion 5.
The cylinder part 5 is a cylindrical wall-shaped part formed so as to surround the cylinder bore 4, and the cylindrical part is connected to the adjacent cylinder bores 4 as shown in FIG.

  That is, the water jacket 6 is formed so as to open to the head mounting surface 3 side by the outer peripheral surface of the cylinder portion 5 and the outer peripheral wall surface formed so as to oppose the water jacket 6. That is, the cylinder block 1 of this embodiment has an open deck type structure in which the water jacket 6 is opened to the head mounting surface 3 side. The water jacket 6 cools the cylinder bore 4 and the like through the cylinder portion 5.

[Example 1 of Cylinder Block Cooling Structure]
Next, the cylinder block cooling structure according to the first embodiment will be described with reference to FIGS.
In the cylinder block 1 of the present embodiment, a spacer 17 is disposed in a phase corresponding to the bolt fastening portion 10 by the head bolt 11 inside the bottom portion in the water jacket 6, and the spacer 17 is the head bolt. 11 is formed so as to prevent the flow of the cooling water 6a on the inner side of the bottom portion in the water jacket 6 in a phase corresponding to the bolt fastening portion 10.

  Here, the “phase” with respect to the circumferential shape of the cylinder bore 4 is as follows. That is, the cylinder bore 4, which is a cylindrical hole, has a circumferential shape when viewed in the central axis direction. With respect to the circumferential shape of the cylinder bore 4, an angle on the circumference around the position of the central axis is determined. This angle (angle range) is a “phase” with respect to the circumferential shape of the cylinder bore 4.

Accordingly, the phase corresponding to the bolt fastening portion 10 by the head bolt 11 with respect to the circumferential shape of the cylinder bore 4 is the center axis in the direction of the central axis in which the cylinder bore 4 has a circumferential shape as shown in FIG. The angle on the circumference centered at the position C is a predetermined angle range α1 in the direction including the bolt fastening portion 10 and the vicinity thereof from the center (position C).
The phase other than the bolt fastening portion 10 by the head bolt 11 with respect to the circumferential shape of the cylinder bore 4 means that the bolt fastening portion 10 and the vicinity thereof are located from the center (position C) as shown in FIG. This is a predetermined angle range β1 in a direction that does not include. In other words, a predetermined angular range in the front-rear direction and the thrust / anti-thrust direction with respect to the cylinder bore 4 is obtained.

In the configuration in which four bolt fastening portions 10 are provided at substantially equal intervals around the cylinder bore 4 as in the present embodiment, the phase (angle range α1) corresponding to the bolt fastening portion 10 as described above has each cylinder bore. There will be four locations for each of the four. There are also four theoretically corresponding phases (angle range β1) other than the bolt fastening portion 10, but the water jacket 6 is not interposed between the adjacent cylinder bores 4 as shown in FIG. For this reason, the front and rear are sandwiched between the other cylinder bores 4 in the number of portions where the other cylinder bores 4 do not exist next to each other, that is, the cylinder bores 4 positioned at the front and rear ends of the cylinder block 1. In the case of the cylinder bore 4, there are two locations in the thrust direction and the anti-thrust direction.
Hereinafter, the phase (angle range α1) corresponding to the bolt fastening portion 10 by the head bolt 11 with respect to the circumferential shape of the cylinder bore 4 will be referred to as “bolt phase”, and the phase corresponding to other than the bolt fastening portion 10 (angle range β1). Is “non-volt phase”.

  The spacer 17 partially fills the space in the water jacket 6 and adjusts the area and strength with which the cooling water 6a hits the cylinder portion 5 to make the temperature of the wall of the cylinder portion 5 uniform. For example, in the vertical direction, the temperature of the upper part of the cylinder part 5 rises due to heat from the combustion chamber, so that the cooling water 6a selectively covers the upper part of the cylinder part 5 with the spacer 17 covering the lower part of the cylinder part 5. It should be cooled strongly.

  The spacer 17 is preferably formed separately from the cylinder block 1 and disposed in the water jacket 6. The reason for this is that by forming a separate body, the degree of freedom of the mold structure in casting of the cylinder block 1 is increased, the productivity is increased, and the deformation of the outer wall of the cylinder block 1 when the cylinder head 2 is fastened adversely affects the cylinder bore 4. And so on. However, the spacer 17 may be formed integrally with the cylinder block 1.

  The material of the spacer 17 is arbitrary such as metal, resin, rubber, sponge, etc., but from the viewpoint of using heat from the combustion chamber, a material with high heat insulation is desirable. From the viewpoint of preventing the deformation of the outer wall of the cylinder block 1 from affecting the cylinder bore 4 when the bolt is fastened to the cylinder head 2, it is desirable that it can be deformed and absorbed when an external force is applied. Further, from the viewpoint of easy arrangement in the water jacket 6, it is desirable that the spacers 17 are formed continuously and integrally with each other.

In this embodiment, as shown in FIGS. 2, 3 (a), and 3 (b), the spacer 17 is provided in the bolt phase portion inside the bottom of the water jacket 6.
That is, on the inner side of the bottom of the water jacket 6, a spacer 17 is disposed in the bolt phase (angle range α1) portion to reduce the flow of the cooling water 6a, whereas the non-bolt phase (angle range). Since the spacer 17 is not provided in β1), the cooling water 6a flows smoothly, so that the cooling of the cylinder part 5 in the bolt phase is suppressed and the cooling of the cylinder part 5 in the non-bolt phase is promoted. -ing

With this configuration, at the bottom of the water jacket 6, the cylinder portion 5 of the bolt phase becomes relatively high with respect to the cylinder portion 5 of the non-bolt phase, and the cylinder bore due to thermal expansion in the bolt phase. The deformation amount is larger than the cylinder bore deformation amount due to thermal expansion in the non-bolt phase.
Specifically, the cooling of the cylinder portion 5 in the bolt phase is suppressed, and the bore deformation in the non-bolt phase is performed as shown in FIG. The bore deformation P1 in the bolt phase is larger than Q1, and the deformation in the bolt phase at the time of assembly deformation can be offset. That is, it is possible to prevent the roundness of the cylinder bore 4 from being deteriorated during actual operation of the engine.

  As described above, the water jacket is formed at the lower portion of the cylinder bore 4 below the lower end of the head bolt 11 where the quaternary deformation during assembly and the quaternary deformation due to thermal expansion occur, that is, at the bottom of the water jacket 6. 6 is formed so as to prevent cooling of the cylinder bore 4 in the bolt phase, that is, the spacer 17 is provided on the inner side of the bottom in the water jacket 6 in the bolt phase. By arrange | positioning, it is comprised so that the cooling water 6a may not flow easily into the bottom part in the water jacket 6 in this bolt phase.

  Thereby, the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the bolt phase is smaller than the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the non-bolt phase. That is, since the temperature of the inner bottom portion of the water jacket 6 in the bolt phase is relatively higher than the temperature of the inner bottom portion of the water jacket 6 in the non-bolt phase, the deformation amount of the cylinder bore 4 due to thermal expansion in the bolt phase is This is larger than the deformation amount of the cylinder bore 4 due to thermal expansion in the non-volt phase.

  Accordingly, it is possible to suppress bore deformation that occurs during engine operation without increasing the number of processes when processing the cylinder block 1. That is, the deterioration of the fourth roundness of the bottom of the water jacket 6 of the cylinder bore 4 due to thermal deformation during actual operation of the engine is prevented, and the friction (sliding resistance) associated with the sliding of the piston 7 in the cylinder bore 4 is reduced. It is possible to prevent engine output limitations and fuel consumption deterioration.

  In the present embodiment, the spacer 17 is arranged not only on the inner side at the bottom of the water jacket 6 but also on the bottom of the water jacket 6 in a phase corresponding to the bolt fastening portion 10 by the head bolt 11. You can also. That is, the flow of the cooling water 6a having the phase corresponding to the bolt fastening portion 10 by the head bolt 11 is completely blocked.

  By configuring as described above, the spacer 17 is disposed in the portion of the bolt phase (angle range α1) inside the bottom of the water jacket 6 to prevent the flow of the cooling water 6a. Since the spacer 17 is not disposed in the non-bolt phase (angle range β1), the cooling water 6a flows, so that the cylinder portion 5 in the bolt phase is not cooled, and only the cylinder portion 5 in the non-bolt phase. Cooling takes place.

  Thus, at the bottom of the water jacket 6, the cylinder portion 5 of the bolt phase is relatively hot relative to the cylinder portion 5 of the non-bolt phase, and the cylinder bore deformation amount due to thermal expansion in the bolt phase is It can be made larger than the cylinder bore deformation amount due to thermal expansion in the non-bolt phase. That is, it is possible to more effectively prevent the roundness of the cylinder bore 4 from being deteriorated during actual operation of the engine.

[Example 2 of Cylinder Block Cooling Structure]
Next, the cylinder block cooling structure according to the second embodiment will be described with reference to FIGS. In addition, regarding each embodiment of the cylinder block cooling structure described below, portions common to the above-described embodiments are denoted by the same reference numerals and detailed description thereof is omitted.
In the cylinder block 1 of the present embodiment, a spacer 27 is disposed outside the bottom portion in the water jacket 6 at a phase corresponding to a portion other than the bolt fastening portion 10 by the head bolt 11. The flow rate of the cooling water 6a at the bottom in the water jacket 6 in a phase corresponding to a portion other than the bolt fastening portion 10 by the bolt 11 is the same as the flow rate of the cooling water 6a in the bottom in the water jacket 6 at the phase corresponding to the bolt fastening portion 10. It is formed so as to be higher than the flow rate.

Specifically, as shown in FIGS. 5 and 6A and 6B, the spacer 27 is provided only on the outside of the bottom of the water jacket 6 in the non-bolt phase portion. .
That is, on the outside of the bottom of the water jacket 6, a spacer 27 is disposed in the portion of the non-bolt phase (angle range β2), and no spacer 27 is disposed in the bolt phase (angle range α2). The path of the cooling water 6a having a non-volt phase is relatively narrower than the bolt phase. Thereby, the cooling of the cylinder part 5 of the non-bolt phase is promoted compared to the bolt phase by raising the flow rate of the cooling water 6a of the non-bolt phase from the bolt phase.

With this configuration, the cylinder bore deformation amount due to thermal expansion in the bolt phase at the bottom of the water jacket 6 is larger than the cylinder bore deformation amount due to thermal expansion in the non-bolt phase.
Specifically, the cooling of the cylinder portion 5 in the non-bolt phase is promoted as compared with the cooling in the bolt phase, so that the bore deformation P2 in the bolt phase is changed in the non-bolt phase as shown in FIG. The bore deformation Q2 is reduced, and the deformation in the bolt phase at the time of assembly deformation can be canceled. That is, it is possible to prevent the roundness of the cylinder bore 4 from being deteriorated during actual operation of the engine.

  In this way, the bottom of the water jacket 6 at the bottom of the cylinder bore 4, that is, the bottom of the water jacket 6 below the lower end of the head bolt 11 in which the deformation at the time of assembly and the deformation of the bore due to thermal expansion occur remarkably. Is formed so as to promote cooling of the cylinder bore 4 in the non-bolt phase, that is, the spacer 27 is arranged at the bottom in the water jacket 6 in the non-bolt phase. Thus, the flow rate of the cooling water 6a at the bottom of the water jacket 6 in the non-bolt phase is configured to be higher than the bolt phase.

  Thereby, the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the bolt phase is smaller than the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the non-bolt phase. That is, since the temperature of the inner bottom portion of the water jacket 6 in the bolt phase is relatively higher than the temperature of the inner bottom portion of the water jacket 6 in the non-bolt phase, the deformation amount of the cylinder bore 4 due to thermal expansion in the bolt phase is This is larger than the deformation amount of the cylinder bore 4 due to thermal expansion in the non-volt phase.

  Accordingly, it is possible to suppress bore deformation that occurs during engine operation without increasing the number of processes when processing the cylinder block 1. That is, the deterioration of the roundness of the cylinder bore 4 due to thermal deformation during actual operation of the engine is prevented, and the friction (sliding resistance) due to the sliding of the piston 7 in the cylinder bore 4 is reduced, thereby limiting the output of the internal combustion engine and fuel consumption. It is possible to prevent the deterioration.

[Example 3 of Cylinder Block Cooling Structure]
Next, the cylinder block cooling structure according to the third embodiment will be described with reference to FIGS.
The cylinder block 1 of this embodiment includes a spacer 37 disposed at the bottom of the water jacket 6, and the spacer 37 has a phase corresponding to the bolt fastening portion 10 by the head bolt 11. The flow of the cooling water 6a at the bottom of the water jacket 6 is blocked at the bottom, and the flow rate of the cooling water 6a at the bottom of the water jacket 6 in a phase other than the bolt fastening 10 by the head bolt 11 is applied to the bolt fastening 10. The corresponding phase is formed so as to be relatively higher than the flow velocity of the cooling water 6 a at the bottom in the water jacket 6.

Specifically, as shown in FIGS. 8 and 9A and 9B, the bolt phase portion is in the bottom of the water jacket 6, and the non-bolt phase portion is in the water jacket 6. The spacer 37 is formed so as to be disposed outside the bottom portion.
That is, a spacer 37 is disposed in the bottom portion of the water jacket 6 at the bolt phase (angle range α3), and the spacer 37 is disposed outside the bottom portion of the water jacket 6 in the non-bolt phase (angle range β3) portion. The cooling water 6a does not flow at the bottom of the bolt phase portion, and the cooling water 6a flows at the bottom of the non-bolt phase portion. That is, at the bottom of the non-bolt phase portion, the flow rate of the cooling water 6a is configured to be relatively higher than the phase corresponding to the bolt fastening portion 10.

  As a result, the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the bolt phase becomes smaller than the cooling amount of the cylinder bore 4 in the inner bottom portion of the water jacket 6 in the non-bolt phase, and the temperature of the inner bottom portion of the water jacket 6 in the bolt phase. The temperature becomes relatively higher with respect to the temperature of the inner bottom portion of the water jacket 6 in the non-volt phase.

Accordingly, at the bottom of the water jacket 6, the cylinder bore deformation amount due to thermal expansion in the bolt phase is larger than the cylinder bore deformation amount due to thermal expansion in the non-bolt phase.
Specifically, the cooling of the cylinder part 5 in the bolt phase is not performed, and the cooling of the cylinder part 5 in the non-bolt phase is promoted, so that the bore deformation P3 in the bolt phase is further improved as shown in FIG. As it becomes larger, the bore deformation Q3 in the non-bolt phase becomes smaller, and the deformation in the bolt phase during assembly deformation can be further offset. That is, it is possible to further prevent deterioration of the roundness of the cylinder bore 4 during actual operation of the engine.

  In this way, the bottom of the water jacket 6 at the bottom of the cylinder bore 4, that is, the bottom of the water jacket 6 below the lower end of the head bolt 11 in which the deformation at the time of assembly and the deformation of the bore due to thermal expansion occur remarkably. The spacer 37 is formed so as to block the flow of the cooling water 6a at the bottom of the bolt-phase water jacket 6 and to increase the flow rate of the cooling water 6a at the bottom of the non-bolt-phase water jacket 6. That is, by preventing the cooling of the cylinder bore 4 in the bolt phase and promoting the cooling of the cylinder bore 4 in the non-bolt phase, the amount of deformation of the cylinder bore 4 due to thermal expansion in the bolt phase is It becomes larger than the deformation amount of the cylinder bore 4 due to thermal expansion in the non-bolt phase.

  Therefore, it is possible to further suppress the bore deformation that occurs during engine operation without increasing the number of processes when processing the cylinder block 1. That is, the deterioration of the roundness of the cylinder bore 4 due to thermal deformation during engine operation is prevented, and the friction (sliding resistance) associated with the sliding of the piston 7 in the cylinder bore 4 is further reduced, thereby limiting the output of the internal combustion engine. This can further prevent deterioration of fuel consumption.

The top view of the whole cylinder block. The horizontal sectional view in the water jacket bottom part of the cylinder block which concerns on Example 1 of this invention. (A) is the sectional view on the A1-A1 line in FIG. 2, (b) is the sectional view on the B1-B1 line in FIG. The schematic diagram which shows the bore deformation | transformation which concerns on Example 1 of this invention. The horizontal cross section in the water jacket bottom part of the cylinder block which concerns on Example 2 of this invention. (A) is the sectional view on the A2-A2 line in FIG. 5, (b) is the sectional view on the B2-B2 line in FIG. The schematic diagram which shows the bore deformation | transformation which concerns on Example 2 of this invention. The horizontal cross section in the water jacket bottom part of the cylinder block which concerns on Example 3 of this invention. (A) is the sectional view on the A3-A3 line in FIG. 8, (b) is the sectional view on the B3-B3 line in FIG. The schematic diagram which shows the bore deformation | transformation which concerns on Example 3 of this invention. The schematic diagram which shows arrangement | positioning of the bolt fastening part with respect to a cylinder bore, and the conventional bore deformation | transformation.

Explanation of symbols

1 Cylinder block 2 Cylinder head 3 Head mounting surface (Cylinder head mounting surface)
4 Cylinder bore 5 Cylinder part 6 Water jacket 7 Piston 10 Bolt fastening part (fastening part)
11 Head bolt (fastening member)
17 Spacer

Claims (3)

A cylinder head mounting surface to which the cylinder head is fixed by a fastening member;
A cylinder bore opened in a cylindrical shape on the cylinder head mounting surface;
A water jacket formed in a groove shape around the cylinder bore;
A cooling structure for a cylinder block comprising:
At the bottom of the water jacket,
The amount of cooling of the cylinder bore in the phase corresponding to the fastening portion by the fastening member,
Than the cooling amount of the cylinder bore in the phase corresponding to other than the fastening part by the fastening member,
A relatively small member
Provided in the water jacket,
A cylinder block cooling structure characterized by the above. The member is
A spacer disposed at a phase corresponding to a fastening portion by the fastening member at least inside the bottom portion in the water jacket;
The spacer is formed to block the flow of cooling water at least inside the bottom of the water jacket in a phase corresponding to the fastening portion by the fastening member.
The cylinder block cooling structure according to claim 1, wherein: The member is
A spacer disposed outside the bottom of the water jacket and in a phase corresponding to a portion other than the fastening portion by the fastening member;
The spacer has a flow rate of cooling water at a bottom portion in the water jacket of a phase corresponding to a portion other than the fastening portion by the fastening member, and a cooling water flow rate at a bottom portion in the water jacket of a phase corresponding to the fastening portion by the fastening member. Formed to be higher than the flow rate,
The cylinder block cooling structure according to claim 1, wherein the cylinder block cooling structure is provided.

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